Preliminary report on the geology of the coastal plain of Georgia

. GEOLOGICAL SURVEY OF GEORGIA
S. W. McCALLIE, State Geologist
BULLETIN NO. 26
PRELIMINARY REPORT
ON THE
GEOLOGY OF THE COASTAL PLAIN
OF
GEORGIA
BY
OTTO )TEAT.CH,
Assistonf St~te Jeolog:..t of Goorgi?,
AND LLOI'"l) WILLIAM STEPHENSON
Assistant Geologist, U.S. G. S.
PREPARED IN CO-OPERATION WITH THE UNITED STATES GEOLOGICAL SURVEY UNDER THE DIRECTION OF T. WAYLAND VAUGHAN,
Geoloe:ist in Charge of Coastal Plain Investigations.
ATLANTA, GA. FOOTE & DAVIES CO.
1911

THE ADVISORY BOARD
OF THE
Geological Survey of Georgia
in the Year 1911

(Ex-Officio)

H1s ExcELLENCY, HOKE SMITH, Governor of Georgia PRESIDENT OF THE BoARD

HoN. PHILIP COOK ________________________ Secretary of State

HoN. W. J. SPEER____~--------~----- .. -- ___ ._State Treasurer

,~ ' ' \ j" , ..

-'

~ ~

HoN. W. A. WRIGB'f:, ___________________ Co111ptroller-General

HoN. THOMAS _FELDER ____________________ Attorney-General

HoN.

T.

G.

HU)!SON
'.

___________.Comm:ssioner

nf

Agriculture

HoN. M. L. BRJTTAIN _______ Commissioner of Public Schools

CONTENTS

5

TABLE Of CONTENTS

Page

Advisory Board o o o o 0

0

0

0

0

0

0

0

0

0

0

0

0

0

List of Illustrations o o o 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Letter of transmittal, Geological Survey of Georgia

3 15-18
20

Letter of transmittal, Uo So Geological Survey Physiography, by Otto Veatch 0 0 0 0 0 0 0 0

22-23 25-50

Other physiographic divisions of the State

25-27

Cumberland Plateau 0 0

25

Appalachian Valley 0 0

26

Appalachian Mountains

26

Piedmont Plateau

Coastal Plain

0

o 0

0

0

0

26 . 27-57

Fall Line hills 0

28-30

Dougherty plain 0

30-31

Altamaha upland 0

31-34

Southern lime-sink region

34-35

Okefenokee plain 0

35-36:

Satilla coastal lowland or Satilla plain

36-39

Terraces 0

0

0

0

0

39

Drainage o 0

0

0

0



0

0



0

39-41

Lakes and ponds

0

0

0

0

0

0

41-43

Fluviatile and upland swamps Okefenokee Swamp

43-49
44~49V

Other swamps o o 0 o 0 o 0 o 0

49

Springs o o 0

0

0

0



0

0

0

0

0

49-50

Elevations, by Otto Veatch 0 0 0 0 0 0 0 0

50-57

General statement of the geology of the Coastal Plain, by Otto Veatch 58-65

Divisions of Coastal Plain strata

59

Thickness 0

0

0

0



0



0

0

0

0

0

0

0

0

0

59-62

Structure 0 o o o . o o o ... 0 0 0

62

Cretaceous, by Lloyd William Stephenson

66-215

Introductory statement

66

Historical review

67-73

Lower Cretaceous

73-111

Definition

73-77

Areal distribution 0

73

Stratigraphic position

73-74

Lithologic characters 0

74-75

Strike, dip, and thickness 0

75-77

Physiographic expression

77

Paleontologic characters 0

77

Detailed sections

0

0

0

0

0

0

78-108

6

CONTENTS

Chattahoochee River . . . . . . . . . .

78-83

Region between Chattahoochee and Ocmulgee rivers

83-91

Region between Ocmulgee and Savannah rivers

91-105

Savannah River . . . . . . . . . .

. 105-106

Wells south of the belt of outcrop

. 106-108

Correlation .

. 108-111

Upper Cretaceous . .

. 111-215

Eutaw formation

. 111-149

Name . . . .

. 111-112

Definition . .

. 113-117

Areal distribution .

113

Stratigraphic position . .

113

Lithologic characters . .

. 113-115

Strike, dip, and thickness

. 115-116

Physiographic expression . .

116

Paleontologic. characters . .

. 116-117

Detailed sections (Part of formation below the Tombigbee

sand member) . . . . . . . . . . . . . . . . . . . .

. 117-131

Chattahoochee River . . . . . . . . . . . . . .

. 117-123

Region between Chattahoochee a,nd Flint rivers

. 123-131

Detailed sections (Tombigbee sand member)

. 131-140

Chattahoochee River . . . .

. 131-138

East of Chattahoochee River

. 138-140

Correlation . .

. 140-149

Ripley formation

. 149-215

Name . . . .

. 149-150

Definition . .

. 150-155

Areal distribution . .

. 150-151

Stratigraphic position

151

Lithologic characters .

. 151-153

Strike, dip, and thickness

:153-154

Physiographic expression .

154

Paleontologic characters

. 154-155

Detailed sections (Part of formation included within the

zone of Exogyra ponderosa) . . . . . . . . . . . . . . . 155-172

Chattahoochee River . . . . . . . . . . . . . . . . . 155-160

Northeast of Chattahoochee River (typical marine beds) 160-161

Region ,between Chattahoochee and Ocmulgee rivers

(Cusseta sand member) . . . . . . . . .

. 161-172

Detailed sections (Exogyra costata zone) . . . . . . . . . 172-192

Chattahoochee River (typical marine beds) . . . . . . 172-181

Region between Chattahoochee and Ocmulgee rivers

(typical marine beds) . . . . . . . . . . . . . . . . 181-192

Region between Chattahoochee and Ocmulgee rivers

(Providence sand member) . . . . . . . . . . .

. 192-200

Detailed sections (wells south of the belt of outcrop) . . . 200-204

CONTENTS

7

Correlation . . . . . . . . . . . . . . . . . . . . . . ... 204-215

Part of formation included within the zone of Exogyra

ponderosa . . . . . . . . . . . . . . . . . . . . . . . 204-210

Exogyra costata zone . . . . . . . . . . . . . . . . . 210-215

Tertiary and Quaternary, by Otto Veatch and Lloyd William Stephen-

son . . . . . . . . . . .

. 216-456

Eocene . . . . . . . . .

. 216-306

Midway formation .

. 216-226

Name . . . . .

216

Definition . . .

. 2l6-220

Stratigraphic relations

. 216-218

Lithologic characters .

218

Thickness . . . . . . .

218

Paleontologic characters

219

Areal distribution . . . .

219

Physiographic expression

. 219-220

Structure ..... .

220

Economic geology .

220

Local details. . .

. 220-226

Fort Gaines . . . .

. 220-221

Hatcher ...... .

. 221-223

Greer Cave locality

223

Preston ..... .

223

Ellaville .. . . . .

224

Montezuma .....

. 224-226

Wilcox formation

. 226-235

Name ........ .

. 226-227

Definition . . . . . . .

. 227-231

'Stratigraphic relations

. 227-228

Lithologic characters .

228

Thickness ...... .

229

Paleontologic characters

. 229-230

Areal distribution . . . .

230

Physiographic expression ..

230

Structure . . . '. . .

231

Economic geology .

231

Local details . . ..

. 231-235

Foi-t Gaines . .

. 231-234

Cuthbert .. .

234

Weston .... .

. 234-235

Plains .... .

235

Ellaville . . . .

235

Andersonville . . . .

235

Claiborne group . . .

. 235-296

McBean formation .

. 237-284

Name .....

237

8

OON'I;ENTS

Definition . . . . . . . . . . Stratigraphic relations . Lithologic characters .. . Thickness . . . . ... . Paleontologic characters Areal distribution . . . . Physiographic expression Structure . . . . ....
Local details (not including Congaree clay member) McBean Creek area, Richmond and Burke counties Savannah River, Burke County Shell Bluff . . . Demeries Ferry . Hancock Landing Blue Bluff ... Griffin Landing . Lime-kiln Bluff . Richmond County . Hephzibah .... Jefferson County .. Louisville . . . . Washington County Sandersville . . Tennille ... . Sunhill .... . Davisboro .. . Twiggs County . Dry Branch .. Gallemore ... Area west of Ocmulgee River Perry, Houston County Flint River . . . ... Chattahoochee River .. Other localities . . . .
Congaree clay member of McBean formation Local details . . .. Columbia County Grovetown .. . harlem .... . Jefferson County Wrens ..... Glascock County .. Gibson ..... . Washington County Sandersville . Chalker .....

. 237-241 . 237-238
238 239 . 239-240 . 240-241 241 241 . 242-267 . 242-243 . 243-251 . 243-248 248 . 248-249 . 249-250 250 . 250-251 251 251 . 251-253 . 251-253 . 253-255 253 254 254 255 . 255-257 . 255-256 . 256-257 . 257-267 . 258-260 . 260-262 . 262-266 . 266-267 . 267-284 269 . 269-272 . 269-271 . 271-272 272 272 . 272-274 . 272-274 . 274-276 . 274-275 276

CONTENTS
Wilkinson County Gordon . . . Lewiston ...
Twiggs County . . Pikes Peak station
Jones Comity . . Roberts station . . Griswoldville ...
Bibb County .. Economic geology of McBean formation Barnwell sand . Name ..... . Definition . . . . . . . . . .
Stratigraphic relations . . . Lithologic characters . . Thickness ........ . Paleontologic characters .. Areal distribution . . . . '. Physiographic expression Structure ... Local details . . . . . . . . Burke County . . . . . . . Storm Branch and Cox Springs Waynesboro .. Midville . . . . Boyd farm .. Stony Bluff .. Richmond County . Hephzibah .... Berzelia . . . . Jefferson County Louisville . . . Wadley .... Wilkinson County . Mcintyre ..... Twiggs County . . Dry Branch clay mines Jeffersonville ... Bibb County . . . . Browns Mountain Jackson formation .. Name ..... . Definition . . . . Stratigraphic relations Lithologic characters and thickness . Paleontologic characters . . . . . . .

9
. 276-278 . 276-277 . 277-278 . 278-279 . 278-279 . 279-283 . 279-282 . 282-283
283 . 283-284 . 285-296
285 . 285-287 . 285-286
286 286 286 287 287 287 . 287-296 . 287-290 . 287-288 . 288-289 289 . 289-290 290 . 290-291 290 . 290-291 . 291-292 . 291-292 292 293 293 . 293-295 . 293-294 . 294-295 . 295-296 296 . 296-306 296 . 296-299 . 296-297 297 . 297-298

10

CONTENTS

Areal distribution . . . . Physiographic expression Structure . . . .. Economic geology . Local details . . . . . . Calhoun County . . . Crawford County ... Rich Hill .... Houston County . Bonaire .. Perry ... . Tivola ... . Twiggs County Near Dry Branch Westlake ..... Pulaski County .. Johnson County .. Savamiah River .. Johnsons Landing . Oligocene ....... . Vicksburg formation . Name .... . Definition .. . Stratigraphic relations Lithologic characters . Thickness ...... . Paleontologic characters . Areal distribution . . . . Physiographic expression Structure . . . . . Economic geology . . Local details . . . . . . . Chattahoochee River Between Flint and Chattahoochee rivers .Cuthbert, Randolph County Blakeley, Early County . Hilton, Early County . . . Dawson, Terrell County .. Bronwood, Terrell County . Arlington, Calhoun County Colquitt, Miller County . . Andersonville, Sumter County . Americus, Sumter County . . . Exposures on and near Flint River Near Oakfield, Worth and Lee counties Albany and vicinity . . . . . . . . . Nigger Head Bend, Mitchell County .

298 298 298 . 298-299 . 299-306 299 . 299300 . 299-300 . 300-304 . 300-301 . 301-303 . 303-304 . 304-305 304 . 304-305 305 . 305-306 306 306 . 306-362 . 306-324 . 306-307 . 307-311 . 307-308 . 308309 309 . 309-310 310 310 310 311 . 311-324 31] . 311-314 311 . 311-312 312 312 312 313 313 313 314 . 314-322 . 314-316 . 316-319 319

CONTENTS
Dewitt, Mitchell County .. Newton, Baker County . . Bainbridge . . . . . . . . Brinson, Decatur County . Between Flint 'and Ocmulgee Rivers Elko, Houston County . Ocmulgee River .. Hawkinsville ..... . Oconee River . . . . . . Dublin, Laurens County . Exposures on and near Savannah River Girard and Flint Branch, Burke County Johnsons Landing ....... . Hershman Lake, Screven County Millhaven, Screven County Apalachicola group . . . . . . Chattahoochee formation .. Name ..... . Definition . . . . . . . Stratigraphic relations Lithologic characters . Thickness ...... . Paleontologic characters . Areal distribution . . . . Physiographic expression Structure ... Economic geology . Local details . . . . . . Decatur County . . . Bainbridge and vicinity . Faceville ... . Recovery ... . Wylie Landing Grady County .. Whigham ... Ocklockonee River .. Thomas County .... Original Pond and other localities Boston ......... . Other localities . . . . . . Withlacoochee River . . Allapaha River . . . . . . Rock House, Crisp County . Ocmulgee River . . . . . . Millen, Jenkins County .. Jacksonboro, Screven County

11
319 320 . 320322 322 322 322 . 322-323 . 322-323 323 323 . 323-324 323 324 324 324 . 324-362 . 324-342 324 . 325-328 325 326 326 . 326327 327 . 327-328 328 328 . 328-342 . 328334 . 328-333 . 333-334 334 334 . 334-336 . 334-336 336 . 336-339 . 336-338 338 . 339-342 . 339-340 340 340 340 341 . 341342

12

CONTENTS

Alum Bluff formation Name ..... . Definition . . . . 'Stratigraphic relations .. Lithologic characters .. . Thickness ....... . Paleontologic characters Areal distribution . . . . Physiographic expression Structure . . . . . Economic geology . . . . Local details . . . . . . . . . Bainbridge, Decatur County Climax, Decatur County . . Attapulgus, Decatur County . . . Whigham and Cairo, Grady County Ocklockonee River . . . . . . . . Thomasville and Boston, Thomas County . Withlacoochee River Allapaha River . . . . Suwanee River . . . . ,St. Mary's River . . . Ocmulgee River . Oconee River . . . . Altamaha River .. Ogeechee River . . Savannah River .
Miocene . . . . ... Marks Head marl . Name .....
Definition . . . Stratigraphic relations
Lithologic characters and thickness
Areal distribution and structure
Paleontologic characters . . . . Economic geology .
Duplin marl . . Name ....
Definition .. Stratigraphic relations . . Lithologic characters and thickness . Areal distribution and structure
Paleontologic characters .
Economic geology .
Undifferentiated Miocene . . . . .

. 342-362 . 342-343 . 343-346
343 . 343-344
345 345 . 345-346 346 346 346 . 347-362 . 347-348 . 348-349 . 349-350 . 350-351 351 . 351-352 . 352-353 . 353-354 355 356 . 356-358 . 358-359 . 359-360 360 . 361-362 . 362-379 . 363-366 363
. 363-366 363 363
364
. 364-366 366
. 366-369 366
. 366-369 366
. 366-367. 367
. 367-369
369 369

CONTENTS
Local details . . . . . . Savannah River . Hudsons Ferry Marks Head .. Porters Landing and vicinity Mount Pleasant Landing Sisters Ferry . . . . . Frying Pan Landing . . Ebenezer Landing . . . . Purisburg, South Carolina . Altamaha River ...... . Bugs Bluff and Buzzards Roost Bluff . Doctortown . . .. Glynn County . . . . . . Brunswick ..... . Livingston Plantation . Camden County .. Owens Ferry ..
Pliocene Historical review . Charlton formation Local details . St. Marys River . Stokes Ferry Hicks Bluff . . Red Bluff ... Schoolhouse Bluff _ Rand Landing . Clay Landing . . Nettles Landing Cow Ford . . . . Sawpit Landing Folkston Chalk Bluff . . Orange Bluff . Altamaha (Lafayette ?) formation . Name ...... . Definition . . . . . . . . . Stratigraphic relations Lithologic characters Thickness ..... . Paleontology and age Areal distribution . . Physiographic expression Structure ....... . Conditions of deposition

13
. 370-379 . 370-376 370-371
371 . 371-373 . 373-374 . 374-375
375 375 . 375-376 . 376-377 376 377 . 377-379 . 377-378 . 378-379 379 379 . 379-423 . 380-392 . 392-400 . 393-400 . 393-400 . 393-394 394 395 395 . 395-396 396 . 396-397 397 398 . 398-399 . 399-400 400 . 400-423 . 400-401 . 401-409 . 401-402 . 402-405 406 . 406-407 407 . 407-408 408 . 408-409

CONTENTS
Local details . . . . . . . . . . . . . Altamaha River . . . . . . . . . East and north of Altamaha River . West of Altamaha and Oconee rivers tyestern and southern localities
Pleistocene . . . . . . . Columbia group . . . . . . Okefenokee formation . . Coastal terrace deposits Local details . . . . Surficial sands . Deposits beneath the surficial sands Fluviatile terrace deposits Local details . . . . . . . Chattahoochee River Flint River . . . Ocmulgee River . Savannah River Ogeechee River Other rivers Satilla formation . . . . Coastal terrace deposits Local details . . . . Savannah, Chatham County Crescent, Mcintosh County . Glynn County ....... . Camden County, Satilla and St. Marys rivers . Fluviatile terrace deposits . . . . . Ogeechee River . . . . . . . Ocmulgee and Oconee rivers Altamaha River ... Flint River . . . . . Chattahoochee River Other rivers . . . . .
Recent. Surficial gray sands of the upland .
Local details . . . . . . . Fall Line localities . . "Wire-grass" sand hills

. 409-423 . 409-414 . 414-417 . 417-420 . 420-423 . 424-445 . 425;445 . 425-434 . 425-427 . 427-428 . 427-428
428 . 428-430 . 431-434
431 432 . 432-433 433 433 . 433-434 . 434-445 . 434-437 . 437-440 . 437-438 . 438-439 439 . 439-440 . 441-445 443 443 . 443-444 444 444 . 444-445
. 445-447 . 447-456 . 451-456 . 451-454 . 454-456

ILLUSTRATIONS

15

. ILLUSTRATIONS
PLATES
Opposite Page
Plate 1. A.-Pyles Marsh, 11 miles northwest of Brunswick, showing timber killed by the encroachment of salt water upon the land, and old stumps in the foreground
B.-Channel of Little Ocmulgee River one mile east of McRae, Telfair County . . . . . . . . . . . . . . . . . . 32
II. A.-Terrace and escarpment bordering St. Marys River (Florida side) opposite Traders Hill, Charlton County, Ga..
B.-Satilla terrace plain immediately west of New Savannah Bluff, Savannah River, Richmond County. . . . 40
III. A.~Sand hill on east side of Little Ocmulgee River, two miles northeast of Helena, Telfair County . . . . . .
B.-A lime-sink pond known as Waving Pond, seven miles northwest of Sylvester, Worth County . . . . . . . . 48
IV. A.-Interior of Big Pond, seven miles north of Baxley, Appling County . . . . . . . . . . . . . . . . . . . . .
B.-A lime-sink pond in the Chattahoochee formation, on the property of Mrs. Mitchell, six miles west of Boston, Thomas County . . . . . . . . . . . . . . . . . . . . . 56
V. Table showing the lithologic variations of the eastern Gulf Cretaceous deposits, and the age relationships of the Cretaceous deposits of Georgia to those of the remainder of the eastern Gulf region; also the correlation of the eastern Gulf Cretaceous with the Carolina and Middle Atlantic Cretaceous . . . . . . . . . . . 72
VI. A.-Clay pit at plant of the Georgia Kaolin Company, two miles southeast of Dry Branch, in Twiggs County, Ga .
B.-Exposure in cut of Columbus-Seale road, four miles southwest of Columbus, Ga., in Russell County, Ala . . 80
VII. A.-Thomas Bluff, Chattahoochee River, one mile below the mouth of Bull Creek, Muscogee County, Ga . .
B.-Exposure in cut of Columbus-Macon road, 3% miles northeast of Columbus, Ga . . . . . . . . . . . . . . 88
VIII. A.-Exposure on right bank of Chattahoochee River at Broken Arrow Bend, 101;2 miles below Columbus, Ga .
B.-Exposure in cut of Steam Mill road, 7 miles east of Columbus, Ga . . . . . . . . . . . . . . . . . . . . 96
IX. A.-Slick Bluff, Chattahoochee River, right bank, 14 miles below Columbus, Ga. . . . . . . . . . . . . . . . . . .
B.-Sandstone dike in clay of Eutaw formation at Slick Bluff . 104
X. A.-Indurated layer of fossiliferous marine sand in bed of Ochillee Creek, at Ochillee, Chattahoochee County, Ga .
B.-Exposure in cut of Columbus-Lumpkin road, 13 miles south of Columbus, Ga . . . . . . . . . . . . . . . . . 112

16

ILLUSTRATIONS

XI. A.-Bluff below Banks Landing, Chattahoochee River, 26lh miles below Columbus, Ga., left bank . . . . . . . . .
B.-Bluff at Snake Shoals, Chattahoochee River, 30 miles below Columbus, Ga., right bank . . . . . . . . . . . . . 120

XII. A.-Bluff at Blufftown, Ga., 311,4 miles below Columbus, Ga. B.-Exposure in cut of Seaboard Air Line Railway, 2lh miles northwest of Cusseta, Chattahoochee County, Ga . . . . 128

XIII. A.-Exposure in cut of Seaboard Air Line Railway, at Manta Station (Hichitee P. 0.) Chattahoochee County, Ga ..
B.-Exposure in cut of Seaboard Air Line Railway, three miles east of Cusseta, Chattahoochee County, Ga. . : . 136

XIV. A.-Exposure in gully in Buena Vista-Tazewell road, six

miles northeast of Buena Vista, Marion County, Ga..

B.-"Sand stream," one mlle north of Tazewell, Marion

County, Ga. . . . . . . . . . . . . . . . . . . .

. 160

XV. A.-Exposure on Mercers Mill Creek near Georgetown, in

Quitman County, Ga. . . . . . . . . . . . . . . .

B.-Bluff on Chattahoochee River at Eufaula, Ala. . . .

. 176

XVI. A.-The "Narrows" of Pataula Creek, nine miles north of

Fort Gaines, Clay County, Ga. . . . . . . . . . .

B.-Waterfall at upper end of the "Narrows" . . . . . .

. 184

XVII.

A.-Exposure in cut of Southern Railway, about one-third
mile north of Zenith Station, Crawford County, Ga.. B.-Cut of Atlanta, Birmingham & Atlantic Railroad, ll/s
miles north of Ideal, Macon County, Ga. . . . . . . . . 192

XVIII. A.-Gully lOJh miles northeast of Georgetown, in Stewart

County, Ga. . . . . . . . . . . . . . . . . . . . . .

B.-Cut of Central of Georgia Railway, one mile southeast

of Buena Vista, Marion County, Ga . . . . . .

. 208

XIX.

A.-Ostrea Georgiana bed at Shell Bluff, Savannah River, Burke County . . . . . . . . . . . . . . . . . . . . . .
B.-Layer of pisolitic clay bowlders near the base of the Claiborne group in a pit of the American Clay Company, Eleven Mile Post, Twiggs County . . . . . . . . . 240

XX. A.-Bed of fullers earth in Congaree clay member of McBean formation, pit of General Reduction Company,.12 miles southeast of Macon, near the Macon, Dublin, & Savannah R. R., Twiggs County . . . . . . . . . . . . . .
B.-Cut of Macon, Dublin, & Savannah R. R., 12lh miles southeast of Macon, near Pikes Peak Station, Twiggs County, showing Congaree clay member of McBean Formation . . . . . . . . . . . . . . . . . . . . . . . 272,

XXI. XXII.

A.-Exposure of limestone of the Jackson formation in a quarry near the Georgia, Southern, & Florida Ry., 1lh miles south of Tivola, Houston County . . . . . . . .
B.-Exposure of limestone of the Jackson formation in a gully at Rich Hill, five miles southeast of Roberta, Crawford County . . . . . . . . . . . . . . . . . . . . . . . . 296
A.-Masses of flint from the Vicksburg formation in bed of Flint River, eight or nine miles above Bainbridge, Decatur County . . . . . . . . . . . . . . . . . . . .
B.-Exposure of flint and limestone of the Vicksburg for-

ILLUSTRATIONS

17

mation just above Dewitt Ferry, Flint River, Mitchell County . . . . . . . . . . . . . . . . . . . . . . . . . . 312

XXIII.

A.-Sink in Chattahoochee limestone near Recovery, Decatur County . . . . . . . . . . . . . . . . . . . . . . . .
B.-Sink in Chattahoochee limestone, known as Original Pond, showing the limestone rock at edge of pond, on property of H. C. Copeland & Co., three miles west of Metcalf, Thomas County . . . . . . . . . . . . . . . 328

XXIV.

A.-iExposure of limestone of the Chattahoochee formation

at Stony Lake Bluff, Withlacoochee River, seven miles

southeast of Quitman, Brooks County . . . . . . . .

B.-Exposure of Chattahoochee limestone in bank of With-

lacoochee River, New Bridge (or Horn Bridge) three

miles below the Valdosta Southern R. R. bridge,

Lowndes County . . . . . . .

. . . . . . . 336

XXV.

A.-Exposure of partially indurated, phosphatic, calcareous sand of the Alum Bluff formation, Allapaha River. Statenville, Echols County . . . . . . . . . . . . . .
B.-Lower Sister Bluff, Altamaha River, Appling County, showing strata of the Alum Bluff and Altamaha (Lafayette?) formations . . . . . . . . . . . . . . . . 352

XXVI.

A.-Unconformity, probably between the Marks Head marl and the Duplin marl, at a wood landing just above Enochs wood landing, 67%, miles above Savannah,
Screven County . . . . . . . . . . . . . . . . . . . . B.-Exposure of Charlton formation, St. Marys River, right
bank (Florida side), Stokes' Ferry, 11 miles south of St. George, Charlton County, Ga. . . . . . . . . . . . 376

XXVII.

A.-Exposure of Charlton formation, St. Marys River, right bank (Florida side) one mile above Traders Hill, Charlton County, Ga. . . . . . . . . . . . . . . . .
B.-Exposure of Charlton formation, St. Marys River, at Atlantic Coast Line R. R. bridge (Florida side), three miles southeast of Folkston, Charlton County, Ga. . . . 392

XXVIII.

A.-Cut of Atlantic Coast Line R. R., west of Climax, Decatur County, showing strata of the Altamaha for-
mation . . . . . . . . . . . . . . . . . . . . . . . . B.-Characteristic mottling in weathered phase of the Alta-
maha formation, cut of Atlantic Coast Line R. R., west of Cairo, Grady County . . . . . . . . . . . . . . 416

XXIX.

A.-Deposit of pure white sand used in the manufacture of glass, probably belonging to the Okefenokee formation, two miles northeast of Lumber City, Telfair County . .
B.-Beards Bluff, Altamaha River, Tattnall County, showing prominent clay layer in Satilla formation . . . . . . . 440

XXX.

A.-Cut of Macon, Dublin & Savannah R. R. through a sand hill on east side of Oconee River, near DU!blin, Laurens County . . . . ........ .
B.--Exposure of residual, surficial sand in a sand pit near Howard, Taylor County . . . . . .

. 448

18

ILLUSTRATIONS

FIGURES

Page.

Fig. 1. Sketch map showing physiographic divisions of the Coastal

Plain . . . . . . . . . . . . . . . . . . .

28

Fig. 2. Profile from Macon southeast to Brunswick . .

37

Fig. "? Profile sketch from Homerville to Cumberland Island .

46

Fig. 4. Profile from Okefenokee Swamp to Kings Ferry, Florida, along line D-E, on map of Okefenolcee Swamp . . . . . . 47

Fig. o). Sketch map of the Coastal Plain of Georgia, showing relation

of drainage to geologic structure . . . . . . . .

63

Fig. 6. Sketch map of Chattahoochee River, Columbus, Ga., to Fort

Gaines, Ga. . . . . . . . . . . . . . . . . . .

79

Fig. 7. Sketch showing relation of Lower Cretaceous beds to Eutaw formation at bluff below mouth of Upatoi Creek . . . . . 83

Fig. S. Sketch showing J:elation of Cretaceous and Eocene strata at Phinizy Gully, near Grovetown, Ga. . . . . . . . . . . . 102

Fig. 9. Sketch showing the relations of Lower Cretaceous beds and the Eutaw formation to each other and to overlying
Pleistocene terrace depo&its . . . . . . . . . . . . . . . 127

Fig. 10. Section constructed from exposures in cuts of Southern

Railway, from Zenith, Ga., northward, for about three-

quarters of a mile . . . . . . . . . . . . . . . .

167

Fig. 11. Section in cut of Central of Georgia Railway, 11;!! miles

northeast of Fort Valley

168

Fig. 12. Section in cut of Central of Georgia Railway, 12 miles

northeast of Byron, Ga.

170

Fig. 13. Section in cut of Central of Georgia Railway, six miles southeast of Eufaula, Ala., in Quitman County, Ga. . . . . . . 193

MAPS

1. Map of Okefenokee Swamp and adjacent region

44

~- Geologic map of the Coastal Plain of Georgia

58

LETTER OF TRANSMITTAL
GEoLOGICAL SuRVEY oF GEORGIA, ATLANTA, November 1, 1911.
, To Hi& Excellency, HoKE SMITH, Governor and President of the Advisory Board of the Geological Survey of Georgia.
Sm: I have the honor to transmit herewith a preliminary report on the Geology of the Coastal Plain of Georgia, to be published as Bulletin No. 26 of this Survey. This report, which is the result of co-operative work between the State Geological Survey of Georgia and the United States Geological Survey, brings together in a systematic form all of the data so far collected by these surveys on the stratigraphic geology of the Coastal Plain of this State. By the aid of the information herein given it is now possible to work out to a greater advantage the various problems of economic geology which present themselves in South Georgia.
Very respectfully yours, S. W. McCALLIE, State Geologist.

I I

LETTER Of TRANSMITTAL
\VASHINGTON, June 10, 1911. PRoF. S. W. :McCALLIE,
State Geologist of Georgia, Geological Survey of Georgia, Atlanta, Ga.
SrR: I ha,e the honor to transmit herewith the mann8cript of a report entitled "The Geology of the Coastal Plain of Georgia with special reference to the stratigraphy, prepared under the direction of Thomas Wayland Vaughan, by Otto Veatch and Lloyd ~William Stephenson," in co-operation between the United States Geological Survey and the Geological Survey of Georgia.
This report results from an agreement for the study of the geology and underground 'vater resources of the Coastal Plain of Georgia, entered into by the United States Geological Survey and the Geological Survey of Georgia in 1908. According to this agreement Dr. Vaughan was to have the direction of the investigations, while each co-operating orgainzation was to contribute the services of one geologist until two reports should be completed. One report, on the Stratigraphy of the Coastal Plain of the State, it was agreed, would be published by the Geological Survey of Georgia; while the other report, on the Underground Water Resources of the Coastal Plain of the State, would be published by the United States Geological Survey. The manuscript I am transmitting to you is to be published by the Geological Survey of Georgia.
The Geological Survey of Georgia assigned for this ~work :Mr. Otto Veatch, Assistant State Geologist, while the United States Geological Survey assigned Dr. L. W. Stephenson. Dr. Vaughan has had general supervision of the investigations and he has contributed the determinations of the invertebrate fossih of the Tertiary and Quaternary formations and the inferences as to the correlation of the formations of these two systems. He has also contributed the results of his own field work, which has extended over a period from 1900 to 1910.

Dr. Stephenson is author of the section on the Cretaceous formations. ln his paleontologic studies he has had aT his disposal, in addition to his own collections, exhaustive collections made h~ Dr. Stanton in 1891 from several localities on Chattahoochee River, and a number of sma!ler collections made by other investigators in Georgia. For purposes of comparison he was alw g-in11 access to the various collections of Cretaceous fossils in the tnitell States N ationa1 ::\luseum. Dr. Stephenson ha,; also bendi tc(1 from the suggestions awl criticisms of Dr. Sta11tcm, \\hose \Yide klw\Yl("ilgt of the Cretaceons fmmas of Xorth ~'unerica amply tit~ him to pa~" judgment 011 the \York of students of lesser experience. ::\Ir. E. \\". Berry, of ,Jolms Hopkins Fnivc.rsity, has contributed lists of fost'il palnts from the Cretaceous formations of Georgia, with annotations, which have been incorporated in the report. :?\Ir. Y catch has supplied numerous unpublished notes on the Cretaceous areas of Georgia, and has also contributed orally much information of value concerning the region. :Mr. Yeatch has >nitten the chapter on the Physiography of the Coastal Plain, has furnished the list of eleYations, has 1vritten the infrodnctory chapter on the geology of the Coastal Plain, and is the senior author of the section describing the Stratigraphy of the Tertiary and Quaternary formations. Dr. Stephenson participated in the field work within this area and has aided in the preparatiou of the manuscript.
Although this report constitutes a decided advance in our knowledge of the geology of the Coastal Plain of Georgia, there is still needed a large amount of detailed investigation. This statement particularly applies to the Tertiary and Quaternary formations. The statements in the report are, in the main, conservative, as it is desired not to claim greater definiteness or precision than the available facts warrant. The mode of treatment of the subject should assist in directing the further investigations of problems concerning which the present information is inadequate.
Very respectfully, GEo. 0. SMtTH, Director .


THE
GEOLOGY OF THE COASTAL PLAIN
Of GEORGIA
PHYSIOGRAPHY
BY OTTO VEATCH
As an introduction to the study of the physiography of the Coastal Plain the other physiographic divisions of the State will be briefly described. As these other divisions and the Coastal Plain are interrelated in their physiographic history, reference to them will make clearer the account of the geology and topography of the Coastal Plain.
OTHER PHYSIOGRAPHIC DIVISIONS OF THE STATE
Following Hayes' subdivisions of the Southern Appalachian province of the United States, the subdivisions in Georgia are, beginning on the northwest: (1) Cumberland Plateau; (2) Appalachian Valley; (3) Appalachian Mountains ; (4) Piedmont Plain. The fifth physiographic division is the Coastal Plain, which, however, is within itself a separate province.
Cumberland Plateau.-The Cumberland Plateau is made up of flat-ropped mountains or tablelands of Carboniferous strata, and occupies, in Dade and Walker counties, a small area which has an elevation of 1,500 to 2,300 feet above sea level. It is represented in Georgia by Lookout, Pigeon, and Sand or Raccoon mountains. These mountains rise 700 to 1,400 feet above the valleys, and are characterized by comparatively flat tops and have steep, precipikus sides ; they owe their form to the resistant character and synclinal structure of the rock capping them.

2G

GEOLOGY 01' THE COASTAL PLAIX

Appalachian Yalley.-The Appalachian Y alley lies between the Cumberland Plateau on the west and the Appalachian ::\Iountains on the east. Considered as a whole it is a valley, since it is lower than the regions both to the east and west, but \vithin itself it is a region of parallel ridges and corresponding subordinate valleys. The ''alley is 40 to 50 miles wide, extends from the Tennessee line to the southern part of Polk County and across the State into Alabama. It is limited on the east by an abrupt scarp of semi-crystalline schists of the Appalachian Mountain area, the Cartersville fault line. The province lies within the Paleozoic area and is in a region of intensely folded limestones, sandstones, and shales. The ridg0s have a north-south direction, are generally steep-sided and owe their existence both to the structure and the resistant character of the rock composing them, while the valleys have been eroded from the softer strata. The vallevs have an elevation above sea level of 600 to 900 feet a11cl the ridg;s, 1,000 to 1,800 feet.
Appalachian Jiountains.-The Appalachian ::\[ountains area is composed mainly of the Blue Ridge, with lesser mountain groups, both to the east and west. The area occupies the northeastern part of the State; it is roughly delimited on the south by a line from Clarkesville to :Marietta, thence west to Rockmart, Polk County. The Blue Ridge enters the State in Rabun and Towns counties and loses its distinctively mountainous character in Pickens County. As contrasted with the Appalachian Valley and Cumberland Plateau, the region is one of vast1y greater rock complexity, composed of igneous rocks and highly metamorphosed sediments, that have been subjected to great orogenic movements, intense folding and faulting, and erosion since early geological periods. The topography is more rugged, and there is a greater complexity of topographic forms, irregularity of drainage form, and less dependence of ridges upon the strike of the rock. The highest elevation above sea level is about 5,000 feet, while there are a large number of "balds" or knobs which are above 4,000 feet.
P1:edmont Plain.-The Piedmont Plain lies between the Appalachian Mountains and the Coastal.Plain. This is a southward sloping plain ranging in elevation from about 1,200 to 300-400 feet above sea level. The region is one of great rock complexity 1ike that of the Appalachian ]\;fountain area, and the beds haYe been snbjected to intense folding and faulting, but the surface has been planatrd hy erosion, and \vith the exception of a few conspicuous elevations the land presents an even sky line. The streams generally conform to the slope of the plain, and have deeply trenched their courses, pro-

PHYSIOGRAPHY

27

clueing a broken, or hilly topography, in places approaching moun-

tain ruggedness, but the tops of the hills and ridges always present a

level.



COASTAL PLAIN OF GEORGIA

The Georgia Coastal Plain includes that portion of the State lying south of the Piedmont Plain. The contact between these two divisions is known as the Fall Line. This is a somewhat indefinite line which derives its name from the falls or rapids in the rivers at the places where they pass from the Piedmont crystalline rocks to the softer and less resistant rocks of the Coastal Plain. In Georgia this line extends in a northeast-southwest course from Augc1sta through Milledgeville and Macon to Columbus. The "falls" are not precipitous and are indicated by a series of rapids. There is a merging of the topography and the railway traveler in passing from one area to the other rarely recognizes the contact, which is more geological than topographical. That is, no prominent topographic fea hue separates the two regions.
The Coastal Plain has an area of about 35,000 square miles if it is considered as con:fip.ed to the area underlain by Cretaceous and later sediments, but considered purely as a physiographic division, it would perhaps include a portion of the crystalline area or represent the original extent of the Coastal Plain beds and would then have an area betv.;een 36,000 and 37,000 square miles.
Physiographically, the region is a lqw plain having a gentle southward tilt. In contrast to the other physiographic divisions of the State it has been subjected to the forces of erosion for only a comparatively short time, and its topography over the greater part of the area may be described as youthful. On the whole, the Coastal Plain is level, although there are some hilly and broken areas in the northern part; the plain is dissected in places near the Fall Line, and the topography has a sommYhat more mature aspect. The hills, however, never rise above a general level and their tops always present an even sky line. The rocks are mainly unconsolidated, sands, clays, and marls, and their structure is simple. There is consequently an absence of pronounced topographic features due to resistant varieties of rock and the folding of beds, such as characterize the Appalachian Valley and Appalachian Mountains. The plain reaches a maximum elevation of 650-700 feet between Macon and Columbus, and 500-600 feet between Macon and Augusta, and thence slopes gradually at the rate of about three or four feet per mile to sea level. About one-hal of it has an elevation of less than 300 feet, while a 1 large area near the Atlantic coast, about one-seventh of the total, i~ less than 100 feet above sea level. The streams on the whole have

28

GEOLOGY OF THE COASTAL PLAIN

not cut as deep courses as in the older divisions; tributary streams are fewer, and there are large areas, flat and undrained or but poorly drained, particularly in the southeastern part.
While the Coastal Plain may be described as a low, level plain, in comparison with the Appalachian Valley, 1\..ppalachian Mountains and Piedmont Plain, it is not entirely featureless and within itself presents topographic contrasts. , The writer has made the following physiographic divisions: (1) Fall Line hills; (2) Dougherty plain; (3) Altamaha upland; (4) Southern lime-sink region; (5) Okefenokee plain; ( 6) Satilla coastal lowland. The location and extent of these divisions may be seen by reference to the map below.

1/i 0 10 2,0 30 jO 50 MOea
Fig. 1.-Sketch map showing physiographic divisions of the Coastal Plain of Georgia.
FALL LINE HILLS
The Fall Line hills division, as the name indicates, occupies the upper portion of the Coastal Plain. The northern extent is that of the Coastal Plain sediments, or approximately the Fall Line, south of which it forms a belt 40 to 50 miles wide, entirely across the State.

PHYSIOGRAPHY

29

It can not be sharply Jefined, as on the north the topography merges i11to that of the Piedmont Plain and on the south into the level and less broken land of the Dougherty Plain and the Altamaha Upland. In this region, more than in any of the other divisions, the topogTaphic features are due to surface erosion. Stream erosion is more active on account of the greater altitude and has been in progress for a greater period of time. The region is characterized by flat-topped hills or ridges and deep g11llies or "washes." The larger streams have cut courses 200 t0 350 feet below the level of the upland plain and the northern portion of the belt is as broken as the adjacent Piedmont Plain. The region is underlain mainly by sands and clays of the Cretaceous and Eocene and their softness has been favorable for rapid erosion.
In elevation above sea level the higher land west uf the Ocmulgee River varies from approximately 350 to 700 feet; that east of the Ocmulgee, from 300 to 600 feet. The elevations of low water at Columbus, Macon, Milledgeville and Augusta are respectively: 190, 278.6, 241.29, and 98 feet.
Two types of hills are commonly recognized, the sand hills and the red hills. The sand hills are best developed in the upper part of the belt and are. conspicuous in Richmond, Crawford, Taylor, Talbot, Marion and other counties, and are really no more than flat ridges which have a notable covering of gray or brownish, superficial sand. The sand is almost pure quartz, incoherent or loose, and ''aries in thickness from three or four to twenty or thirty feet, but the average thickness over the sand hills is perhaps not more than five or six feet. This sand is probably residual from the underlying Cretaceous and Eocene formations. (Seep. 451.) The soil is poorly productive, and the tree growth is mainly stunted oak and scattered long-leaf pine.
The lower portion of the Fall Line hills belt is mainly red hills, and the gray superficial sand is less widely distributed. The soil of these hills is a bright red sand or red, sandy loam, which is residual from the underlying geological formations, chiefly the Eocene. The red hills are conspicuous in Wilkinson, Twiggs, Houston, ::\lacon, Sumter, Terrell, Randolph, and Stewart counties.
The deep gullies, also known as '~washes" and "ca,-es," which appear in this region, are worthy of note. The softness of the strata together with the high altitudes of the plain above the rivers, timber denudation, and cultivation of the laml, have been especially favoraqle for rapid erosion, and some of the deepest gullies, 100 to 175
feet, are knmvn to have formed since the settlement of the country.
Perhaps the largest aml most pictnresqne of the gnlliPs are 1osated

80

GEOLOGY OF THE COASTAL PLAIN

'vest and north of Lumpkin, Stewart County. The gullies at ProYiclence, eight miles west of Lumpkin, are 100 to 175 feet in deptli, and from 200 yards to one-fourth mile in length. The greatest width is at the head, due to the union of a number of tributary gullies, so that a plan of the upper edge would be roughly bottle-shaped or pear-shaped. A transYerse profile would be V-shaped; a longitudinal profile' would be roughly L-shaped, the horizontal line of the letter, of course, greatly exceeding in length the vertical line. That is, the head of the gully is precipitous and the gradient of the floor so low that the water wh~ch flo1vs through the gully is unable to Parry the load of sand which is 'vashecl down, and it is spread out as deltas and "sand streams." 1\n excellent illustration of a "sand stream" is shown in plate XIV, B, opposite page 160. The strata are unconsolidated sand, containing soft clay layers, and are hence, easily eroded. The recession of the gullies has been Yery rapid, and the 11eepest gully is known to have worked back 000 feet in about 30 years, and to have washed out a space of 10 or 15 acres. As much as five or eYen ten feet "cave" or slnmp at one time after very heaYy rain storms. These gullies are the most pictnresque features of the Coastal Plain, presenting cmions erosion forms, pinnacles, "islands," or blocks of strata cut off from the aclj acent land by erosion, and sharp serrated ridges, while the brigbt red and white sands and the dark green pine tops present a vivid color contrast. Similar deep washes or gullies appear in Quitman, \Yebstcr, ::\Iarion, Crawford, Houston, Twiggs, \V.ilkinson, and \Vashington counties. Tlw deep washes on the sonth side of Hich 1I ill, Crawford County, are, next to the Prm'idence gullies, perhaps the most picturesque. The famous Lyell gullies fom miles west of :Milledgeville are properly "ithin this area, although they are cut entirely in residual clay dorin'd from granite, since a few remnants of the Coastal Plain sediments appear at this locali~y. The gullies are about 50 feet deep. They were visited by Sir Charl~s Lyell in 1842, and subsequently described in his "Travels in North America."

DOUGHERTY PLAIK
This division occupies a large area in the western part of the Coastal Plain. It is characterized by very level tracts, and there are few elevations that may properly be termed hills; it is a region in which there are comparatively few small streams and b1anches and consequently one in which there is little surface erosion, the drainage being in large measure subterranean. It is further characterized by numerous lime-sinks, which form shallow depressions in otherwise level tracts. This division extends from the Chatta-

PHYSIOGRAPHY

31

hoochee to a fe11 miles ca,;t of .E'lint HiYcr, aud includes the greater part or all of the counties of Decatur, )[iller, "\Iitchell, Early, Baker, Calhoun, Dougherty, Handolph, Tenell, Lee aucl Sumter. A small strip extends eastward from the .E'lint to the Oconee, including parts of Dooly, Houston, Pula,ki, aud Laurens counties, and includes most of the area underlain by the limestones of the Vicksburg formation. 1t is rather sharply differentiated from the Altamaha Upland on the east and south, but merges into the .E'all Line hills on the north.
In elevation above sea le1el it varies from approximately 12:l feet in Decatur County to 50 feet in the southern part of Houston County. Much the greater portion of the area is less than 300 feet.
Due to the extensive underground solution of the 8oft underlying limestone, lime-sinks are very numerous and characteristic of the region. These vary in size from small, shallow depressions not more than 100 to 200 feet in diameter to those occupying several hundred acres and to chains of sinks several miles in extent. The sinks usually contain 1v~ter, forming shallow ponds or lakes, and the shallow ponds usually contain a thick growth of cypress and other trees. The amount of water in tho ponds and lakes varieB with the seasons, and during droughts tho smaller ones become dry. The recent desiccation of the sinks is also partly attributed to the removal of timber, thus permitting increased evaporation and oxidation of organie matter. Sinks are aho known to have been suddenly drained through subterranean passages.
The absence of nnmerons small tributary creeks and branches is due not so much to the newness of the land surface as to the fact that a large portion of the drainage is through subterranean streams. Most of the largo creeks flow sluggishly through wide, swampy valleys, and rarely have any considerable bluffs along their courses. Chattahoochee, .E'lint and Ocmulgee rivers have cut deep, terraced valleys 75 to 200 feet below the plain, but haYe comparatively few tributary streams.

AL'Nc}IAI-IA l:PLAXD
This area constitutes the largest physiographic division of the Coastal Plain. Its northern boundary is marked by an irregular line between \Yaynesboro, Tennille, Dublin, Cochran, and Vienna, its western edge thence lying parallel to and a few miles east of Flint River and extending to Decatur County. On the southeast it extends into Effingham, Liberty, Wayne, Pierce, Ware, and Clinch counties, and merges into the sandy pine flats of the Okefenokee Plain. It embraces most of the region popnlarly knom1 as the

32

GEOLOGY OF THE COASTAL PLAIN

"wire-grass country," and is underlain mainly by the Altamaha (Lafayette?) and Alum Bluff formations. The geology, topography, and flora of this region are of peculiar scientific interest and have been the subject of a number of papers and articles.1
The region is an upland only in comparison with the low coastal plains on the southeast and the adjacent Dougherty plain on the west, and on the whole is lower than the Fall Line Hills to the north. It varies in elevation above sea-level from about 125 to 470 feet. It reaches the highest elevation on the north and west, thence there is a gradual slope southeast. There is a steep ascent or escarpment on the west, separating it from the Flint River lowland, which is prominent enough, even in this region of low relief, to be distinguished by the observant traveler without the aid of topographic maps. For example, the rise from Camilla to Pelham, Mitchell County, over the Atlantic Coast Line Railroad is 185 feet in a distance of eight miles, and the rise from Bainbridge east to Climax is 175 feet. Arabi, Crisp County, Ashburn, Sylvester, Pelham, and Climax may be considered as marking approximately the crest of the escarpment; thence there is a decrease in elevation to the southeast.
A characteristic of the topography is lmY, rolling hills, with smooth or softened outlines, which do not rise except along the large rivers more than 40 or 50 feet above the valleys. There is an absence of any features suggesting ruggedness, yet ~t the same time the region is not a monotonous level or flat.
The soil is generally sandy and in places there is a thick mantle of loose gray sand. The area was originally covered with a wonderful forest of long-lea pine. A characteristic growth is wire-grass, Aristida stricta, a long and round-bladed, stiff grass, growing in tufts, six to eight inches high.
Streams are much more numerous than in the Dougherty Plain and the coastal flats. The Altamaha, Ocmulgee, and Oconee rivers hm-e cut valleys. 100 to 150 feet b~low the upland, and have made precipitous bluffs in a few places, but with these exceptions the valleys are shallo"w and those of the small streams mav be described "as dish-shaped, or as having low breast-like slopes. The creeks are generally sluggish and flow through broad, swampy bottoms and
1Loughridge, R. H., Tenth Census._ Yol. YI, Georgia, pp. 15 and 49. Dall, W. H., U. S. Geol. Survey, J:mll. 84, p. 81. Harper, R. M., Phytogeographical Sketch of the Altamaha Grit Region of Georgia : Annals N. Y. Acad. Sci., Yo!. XYII, pt. I, 1906. McCallie, S. W., Underground Waters of Georgia: Ga. Geol. Survey, Bull. 15, pp. 31-32. Veatch, Otto, Altamaha Formation of the Coastal Plain of Georgia: Sci., Yo!. XXVII, 1908, pp. 71-74.

GEOLOGY OF THE COASTaL PLA lll" OF GEORGI A . A. PYLES MARSH, 11 l\IILES ' OR'rHWE T OF BRUNSWICK, SHOWING TU.!REP.
KILLED BY THE ENCROACH:ME T OF ALT WATER UPON THE LAND. OLD STUMPS IN THE FOREGROUND.

PHYSIOGRAPHY

33

are char'"acterized by "clear" water, or water free from sediment, in contrast to the muddy water of the Ocmulgee, Oconee, and Altamaha. Many of the creeks and branches have their sources in flat, moist, densely wooded areas locally known as "bays," a name probably suggested by the dense growth of bay trees in these areas. The name "bay" is generally applied to upland, flat, swampy tracts in which water stands, due to imperfect drainage and dense vegetation which conserves the rainfall. These areas are really swamps but are not alluvial in character. Cluffs Bay, about seven miles west of Waycross (see map opposite page 44), is an example. The name is also applied to arms of creek and river swamps which form entrants into the dry land and are characterized by a dense growth of bay trees. The bays contain \Yater, but there is no well defined channel of a stream or "run." The water is furnished directly by rainfall and by seepage from the surrounding higher land.
In the southeastern part of the Altamaha upland, the land becomes more level, and finally merges into the moist pine flats of the Okefe-nokee plain. Throughout this part there are numerous small cypress ponds, and the valleys of the small streams become more swampy, and the streams themselves have banks not more than a foot or two high. The ponds appear to be the result of shallow depressions or slight irregularities left in the land surface after the retreat of the last sea which covered this area. (See page 42.) Along the northern and western edges of this division in Screven, wilcox, Crisp, Turner, Worth, and Decatur counties, lime-sinks were noted, due to the underground solution most probably of the Chattahoochee limestone formation.
One of the most interesting features of the Altamaha upland is the "sand hills" which border many of the creeks and rivers. These hills slope towards the streams wh~ich they border, but may be only very slightly higher, or not at all higher, than the upland back from the stream. They are made up of gray, yellow, or light brown, unconsolidated, structureless quartz sand, which in places reaches a thickness of' as much as 30 feet. These sand belts may reach a width of as much as two or three miles, parallel to the streams. It has been observed that the sand ridges are generally on the east or left sides of the streams. The only explanation of this which can be offered, and this explanation is merely tentative, is that the prevailing winds might have caused the westward slopes of the ridges to be the steeper, and that the steep slope governed the direction of the present streams by acting as a barrier. These sand deposits appear to be at higher elevations than the accumulations of loose sand on the first and second Pleistocene terraces of the large rivers. The most prominent

34

GEOLOGY OF THE COASTAL PLAIN

of the sand hills or sand belts are those on the east side of the Ohoopee River, in Tattnall County, near Reidsville; along the east side of the Cannoochee ; on the Little Ocmulgee near Helena; along Satilla River from waycross, westward; and on the east and north side of Pendleton Creek, in Emanuel and Toombs counties. At the foot of these hills are sometimes densely wooded, moist sandbeds known as "hammocks." There are in some places shallow depressions, so-called "sand hill" ponds, in these sand belts, which contain water during rainy periods. The origin of these sands is not yet well understood. They may have been formed during the Pleistocene. period, and may be of :fluviatile origin; they have doubtless been shifted and in part redeposited by wind.
In comparison with the Dougherty plain, the Altamaha upland has a rolling topography, streams are more numerous, and while there are a few lime-sinks along its borders, it is on the whole in contrast to the level lime-sink tracts of the former region. It is not so entirely featureless as the swampy tracts along the coast and is better drained. In contrast to the Fall Line hills, there is an absence of ruggedness, and the valleys are shallower and in addition there is a notable di:ffe:rence in the flora.'
SOUTHERN LDIE-sL;U( REGIOX
\
The Southern lime-sink region occupies a small area in the southern part of the State. It embraces the southeastern part of Decatur and the southern halves of Grady, Thomas, Brooks and Lowndes <>ounties and extends into Florida. This division is hilly and is characterized by lime-sinks, lakes, and ponds.
In elevation above sea level, it varies from 150 to 275 feet and the hills rise 50 to 75 feet above the valleys and in a few places as much as 100 feet. The topography is more rugged than that of the adjacent Altamaha upland and the Dougherty plain. This difference and
other characteristics of the division are due mainly to the nature of
the underlying geological formations. The lime-sinks are due to the underground solution of an upper Oliogocene limestone, the Chattahoochee formation, but this is not the surfa<;e formation and is over lain by 50 to 100 feet of sand and clay which is soft and easily eroded, and which probably accounts for the topography being more rugged than that in the western lime-sinK: region. The lakes and ponds are due to depressions caused by the underground solution of limestone or are lime-sinks which contain water. Some of the lakes are several hundred acres in area and are free from timber growth, but the smaller and shallower ponds support a thick cypress growth. Ocean
'Flcological "tndies in thi region have bPPn made by Dr. R. 1\L Harper. Annals. New York Academy of Sciences, Vol. XVII. No. 1, and other papers.

PHYSIOGRAPHY

35

Pond, in the southern part of Luwndes County, is one of the largest

ponds or lakes and has an area of about six square miles. The water-

level in these sinks varies with the seasons, and the water has been

known suddenly to disappear or to rise, due probably to the opening

or stoppage of underground passages.

.

The drainage, as in the Dougherty plain, is to some extent subter-

ranean and hence, small streams are not numerous. The rivers which

flow through the region, the Ocklockonee and Withlacoochee; flow

canal-like, through broad sand-covered terrace plains. The water of

the streams is not muddy, but is dark on account of dissolved and

suspended organic matter, while that of the lakes is clear.

The soil is in many places red, sandy clay, and loam, and the su-

perficial gray sand, characteristic of the Altamaha upland, is not so

widely distributed. The tree growth differs somewhat from that of

the wire-grass region to the north, in that along with the long-leaf

pine there is some o.ak and hiC'kor,y.

OKEFE:'iOKEE PLAIN
This division forms a narrow north-south strip 20 to 40 miles wide in the southeastern part of the Coastal Plain, and includes parts of Effingham, Bryan, Liberty, Wayne, Pierce, Camden, Ware, Charlton, Clinch, and Echols counties. On the west this division is approximately marked by a line from the northeast corner of Effingham County, southwestward to near Groveland, Bryan County, thence a few miles south of Glenville, to near Jesup, and Waycross, and is continued in the western boundary of Okefenokee Swamp. There is only a poorly defined escarpment separating this plain from the Altamaha upland and the two merge, but on the east it is separated from ll. lower coastal' terrace by an abrupt descent or escarpment, which will be mentioned later.
The Okefenokee plain is essentially a featureless, sandy flat, in which there are but few streams. It thus presents a contrast to the rolling topography and dendritic drainage of the Altamaha upland. It is dotted with small cypress and gum ponds and swamps, varying from a few acres or a few miles in extent to the immense Okefenokee Swamp. This swamp is one of the most interesting natural features of the Atlantic Coast and will be described later. The region varies in elevation above sea-level from about 60 toperhaps 125 feet and has an eastward slope of about two f~et per mile. The drainage is poor, at least 25 per cent. of the area being swampy. There are but few branches and creeks and these flow through broad, swampy flats, only slightly lower than the general level. The striking difference in the number of small streams tributary to Satilla, Altamaha, and Cannoo-

36

GEOLOGY OF THE COASTAL PLAIN

chee rivers in th~ A~tamaha upland and in the Okefenokee plain may be seen by exammatron o the map o the State. Streams have in only a few places bluffs as much as 30 or, 40 feet high. The flatness o the plain and its sw'ampy condition are due both to the newness o the land surface, since the retreat o the sea took place at a comparatively recent geological time, together with the low altitude and the :fact that the surface has a heavy covering o loose, porous ::,and, whicl1 absorbs the rainfall and hence lessens surface erosion. The streams are sluggish and with the exception o the Altamaha and Savannah, the water in them is black or coffee color rom organic matter. This region is characterized by moist, long-lea pine and saw-palmetto flats, cypress ponds, gallberry flats, and a thick growth o gums and bays in swamps.
The acts in favor o considering this plain a wave-built, marine terrace, recently raised above sea level, rather than a plain o alluviation or a plain o denudation by stream erosion are: the trend o the plain parallel to the coast and its parallelism to a lower and younger plain, (the Satilla coastal lowland or Satilla plain) which is surfaced with undisturbed beach sand and muds containing shells and other evidence o near coast deposition; this lower plain is separated rom the higher plain by an escarpment which doubtless represents former coast bluffs and there is a poorly defined escarpment on the west o the Okefenokee plain which is more or less parallel to the lower escarpment. The Okefenokee plain is covered with a uniform or homogenous deposito white incoherent sand, which is uncharacteristic o a fluviatile deposit in its structure and composition. There is no well developed drainage system and there are large undrained areas and swamps, which are most plausibly explained as being due to original, inequal ities in the land surface.

SATILLA COASTAL LOWLAND OR SATILLA PLAIN

This division is a low marine terrace plain bordering the Atlantic Ocean. It is 20 to 35 miles wide and includes parts or all o the
counties o Chatham, Bryan, Liberty, Mcintosh, Glynn, auJ Camden. (See map on page 28.) The western edge o the plain is marked by a rise or escarpment 20 to 40 feet high, which is pl'oJU1~nent
at Walthourville, Mount Pleasant, and Waynesville, and a short distance east o Folkston. This escarpment may mark a Pleistoce~o
shore line. The greater part o the plain is 15 to 25 feet above sea level, but
there are a few places which reach an elevation o about 40 feet. The

PHYSIOGRAPHY

37

plain has a slight eastward slope, somewhat difficult to estimate, but probably not more than a foot to the mile. Although it is a low, flat, poorly drained plain,

""0' '
o. <:,
~'1>

"0 '
qFall Line Macon

it presents several different topographic aspects. It ~ differs from the Okefenokee plain chiefly in its lower N

altitude, greater area of swamp and inundated land,

and in topographic forms incident to low coast land.

The western part is on the whole a sandy flat plain

containing an open growth of long-leaf pine. Orig-

inally, in the spring and summer, grass and flowers

were luxuriant in open areas, termed meadows or

"savannas."1 This plain is dotted with small cypress ponds and also contains large swamp areas, in this ~

respect resembling the higher Okefenokee plain.

~

The coast line presents a different aspect. Due to .,

c

recent submergence, the coast line is irregular and a ~ network of sea-islands, tidal rivers, sounds, estuaries, ~~ and marshes have been formed. The land terminates :~

1J r
)>
z
0

as beach on the sea-islands, and in low sand bluffs, ~ ~

not more than 10 or 15 feet above low tide, and as ~"'

marshes at the mouths of the rivers flowing into the ~

ocean. The islands are sand-covered, and some of

them exhibit sand dunes, but the dunes nowhere reach gj great magnitude. The islands form in the aggregate ~ an area of perhaps 500 to 600 square miles. The 25

1J
r
-)>
z

largest are Cumberland, Jekyl, St. Simon, Sapelo, St. ~

Catherine, Skidaway, and Tybee. They are of con- 8"

siderable historical interest and some of them are ~

noted as resorts.

~ ~

The tree growth of the coast land is characterized ;1. by the cabbage palmetto and live oaks, which are ~

more abundant than farther west.

There are two classes of swamp land, the upland

Jesup

swamp and the tidal swamp. The first is represented

by such swamps .as Buffalo Swamp in the western "~'

part of Glynn County which probably represent the :;;

sites of former shallow sounds or coastal lagoons and "'

marshes which have become land surface through up-

lift and the retreat of the sea approximately to its

present position. After this movement, however,

there was again a subsidence of the coast as is indi-

cated by drowned river courses. This subsidence

1An excellent description is given by R. H. Loughridge, Tenth Census, Vol. 6, Cotton Production, Georgia, p. 51.

.AT.L.ANTJC OCEAN

38

GEOLOGY OF THE COASTAL PLAIN

seems to be going on at present, causing the sea slowly to encroach on the land. The best proof of this is the presence of tree stumps and even dead standing trees in brackish water marshes. (See plate I, A, opposite page 32.)
Considerable areas of "tide swamp" occurs along the Savannah, Ogeechee, Altamaha, Satilla, and St. Marys rivers. This lowland bordering the rivers is partly submerged at high tide, and differs from the marsh land chiefly in that it is covered by fresh water and not salt as in the case of the marsh. Tide swamp extends up the above named rivers 10 to 20 miles above the salt marsh, and was at one time utilized in rice-growing and is still so used to a small extent.
The salt marsh reaches its greatest extent at the mouths of the rivers, but probably does not aggregate more than 150 or 200 square miles.' The marsh land is probably due in the main to submergence of the coast, although the silting up of water areas, by sediment carried down by streams, has also doubtless been a factor.
The plain is poorly drained and there are but few streams owing to the newness of the land surface and its low altitude. The streams are sluggish, and are so-called "clear water streams," except the Savannah and the Altamaha, the waters of which are yellow from suspended sediment. The waters of the other streams, however, are dark or even black from organic matter. The slight eastward slope of the plain has caused the streams to flow directly east to the ocean. An interesting effect of the slight eastward slope of this and the higher Okefenokee plain is observed in the case of the Satilla and Little Satilla rivers in Camden County. The Satilla has no tributaries at all entering from the east, and the head branches of the Little Satilla are extended to within one and one-half miles of the Satilla near Atkinson.
Recent submergence has caused a drowning of the streams and in consequence the mouths of the large rivers have been converted into estuaries and rendered navigable by sea-going vessels from 10 to 20 miles from the coast, and small streams which, so far as their lengths are concerned, are really no more than branches or creeks, have been enlarged and are styled rivers. In this latter class are such streams as Crooked River, Turtle River, and Sapelo River. There is also .a network of serpentine water-ways on the sea ishmds which are termed rivers and creeks, but are really no more than natural tidal canals.
lNo survey of the marsh land of the State has yet been made, and hence accurate figures can not be given.

PHYSIOGRAPHY

39

TERRACES
The terraces constitute an interesting physiographic subject in the study of the Coastal Plain. They are intimately connected with the Pleistocene geology and the subject demands further study with the aid of detailed topographic maps, before final conclusions can be offered.
Two1 broad terrace plains parallel to the coast are easily recognized, while the large rivers are bordered by fluviatile terraces believed to be equiYalent in age to the two coastal terrace plains. The terraces are illustrated in fig. 2 and Pl. II. The older is designated the Okefenokee plain, and the younger the Satilla plain. For the area of these plains see map on page 4.
The river terraces are best developed in the upper part of the Coastal Plain along Chattahoochee, Ocmulgee, and Savannah rivers, and are conspicuous at Columbus, Macon, and Augusta. The lower or younger terrace, also known as "second bottoms," lies 15 to 50 feet above the rivers, and is a smooth plain, varying roughly from one-half to three or four miles in width. The second terrace lies 50 to 100 feet above the rivers; it is in this plain that the lower has been cut, and it has been modified to a greater extent by erosion. The upland plain bordering the rivers is from 125 to 250 or 300 feet above river levels. The terraecs \\ill receive further mention in the chapters on Pleistocene geology.

DRAIXAGE OF THE COASTAL PLAIN
The drainage of the Coastal Plain discharges into the Atlantic Ocean and the Gulf of :Mexico. The drainage basins, according to a map by B. 1L Hall,' are: (1) Savannah Basin; (2) Ogeechee Basin;. (3) Altamaha Basin; (4) Satilla and St. Marys Basin; (5) Suwanee Basin; (6) Ocklockonee Basin; (7) Apalachicola Basin, drained by the Chattahoochee and the Flint. The first four dis.-

lit is not improbable that a third higher terrace plain exists, but sufficient proof of its existence has not been obtained to warrant posiLive statements.
water P.owers of Georgia, Geol. Survey Ga., Bull. No. 3-A, p. 16.

40

GEOLOGY 0;;' THE COASTAL PLAD.T

charge into the Atlantic and form considerably the larger drainage area; the remaining three discharge into the Gulf of .Mexico. . The rivers of the Coastal Plain fall naturally into two simple classes: ( 1) those originating in the Piedmont Plain and Appalachian Mountains and thence traversing the Coastal Plain; (2) native streams or those having their source within the Coastal plain. To the first class belong Chattahoochee, Flint, Ocmulgee, Oconee, Aitamaha, Savannah, and Ogeechee rivers, although the last throughout the greater part of its course has the aspect of a stream of the second class. The rivers of the second class are much more numerous, and the principal ones are the Little Ocmulgee, Ohoopee, Oannoochee, Satilla, St. Marys Suwanee, Allapaha, Withlacoochee, and Ocklockonee.
The rivers of the first class have greater drainage areas, carry a greatBr volume of water, have greater lengths, and have cut deeper and wider valleys. The water of these rivers is always muddy, except that of the Ogeechee, whereas the water of the streams of the second class are clear, and this fact furnishes a popular distinction"clear w.ater"' and "muddy water" streams. Especially the Ocmulgee, Oconee, Altamaha, and Savannah are bordered by broad lowlands or swamps, in which a large part of the sediment is clay, while the smaller Coastal Plain rivers of the second class have sandy banks and the low terraces bordering them are composed almost entirely of sand. The explanation is that in the one case a large amount of sediment is derived from the red clay hills of the Piedmont Plain; while in the other the streams flow through geological formations that are predominantly sand, a region where erosion is not active, many of the smaller streams having not even cut through the superficial sands.
The rivers across the Coastal Plain probably assumed their courses on a comparatively level plain, follovving the retreat of the sea from the land and extended their courses across the new land surface, so that, fo; example, the age of the Ocmulgee at the Fall Line is. much greater than the lower 20 or 30 miles of the Altamaha or that part which flows across the later Pleistocene plain. The directions of the streams are due to the initial slope of the new land surface upon which they started their courses. Thus all of the rivers have general south, southeast and east courses, since the tilting of the land surfaces has been in these directions. The rivers have not in all cases formed straight courses to the coast on account of the interposition of certain
'While the native streams of the Coastal Plain are termed "clear," the water is clear only in that it is comparatively free from suspended silt and clay. The water does not possess the transparency of clear mountain streams, but. ts pale brownish or even black from organic matter held in solution and suspension. The water of Suwanee and St. 1\larys rivers. near their source, the Okefenokee Swamp, is of almost inky blackness.

GEOLOGY OF 7'HE CO A S1'A L PLAIN Ole ObOR(}lA.

PLATE II.

A. TERRACE AND E CARPME ,,T BORDERING ST. i\1ARY RIVER (FLORIDA SIDE) OPPO ITE TRADERS HILL, CHARLTON COUNTY, GA .

B. SATILLA 'ERRACE PLAIN IM;\fEDIATELY WEST OF NEW SAVANNAH BLUFF, SAVANNAH RIVER , RICHMOND COUNTY.

PHYSIOGRAPHY

41

topographic and geologic factors. The direction of a stream might have been deflected by slight irregularities in the new land surface or upraised sea-floor, or by certain geological conditions, which it encountered in cutting down its course.
The St. Marys and Satilla rivers present a curious anomaly in the courses they have taken to reach the sea. (See map opposite page 44.) The St. Marys issues from the southern end of Okefenokee Swamp, flows south for about 15 miles, thence east for about eight miles, thence makes a right-angle turn and flows north for a distance of over 30 miles and to within four miles of the Satilla, thence flows to the Atlantic in a course slightly south of east. The Satilla has its source in the Altamaha upland and flows eastward as far as Atkinson in Wayne County, then instead of taking the most direct course to the ocean, which would be the course of the Little Satilla, it flows south for more than 20 miles, thence makes an abrupt turn and Rows east to the Atlantic. These rivers are young, dating probably from the Pleistocene, and are flowing across a newly formed land surface. Their peculiar courses are probably due to the original uneven surface of the upraised sea-floor, caused by low sand ridges or sand heaps such as are incidental to beaches and very shallow seas bordering a low sandy coast-land. The most direct course to the ocean, and the one in conformity with the general slope of the land, which the St. Marys might have taken, is through St. Johns River, Florida, but it was probably deflected to the north by a low sand ridge. There is also a sand ridge separating the St. Marys and the Satilla, which probably prevented their junction.
The almost direct south courses of the Allapaha, Withlacoochee, Little, and Ocklockonee rivers are probably due to a low, southwarddipping and flat topped arch in the upper Oligocene strata. A similar flexure probably exists along the Chattahoochee, as is indicated by the unequal drainage divide between the Flint and the Chattahoochee, the great depth to which the latter river has cut its valley, its trench-like channel and the absence of flood plain swamp, in con" trast to the other large rivers.
The general southeastward and eastward courses of the Satilla, Altamaha, Ogeechee, Savannah and other streams in the Pastern half of thP OoaRta.l Plain, is in consequence of the initial tilt of the land surfacA on which they originated. The explanation of the general insignificance and shortness of northward and westward flowing tributary streams is hence obvious.
LAKES AND PONDS
The lakes and ponds of the Coastal Plain are of three types: (1) those due to lime-sinks; (2) those caused by original shallow depres-

42

GEOLOGY OF THE COASTAL PLAIN

swns in the land surfaces after the retreat of the sea ; (3) riVer flood-plain lakes. ,

Lime-sink lakes and ponds are confined mainly to the western and

southwestern parts of the Coastal Plain, to the areas described above

as Dougherty plain and Southern lime-sink region, but there are also

lime-sinks and small ponds in Screven County, in the southern parts

of Burke, Jefferson, and Washington counties, and along the western edge of the Altamaha upland. The depressions which lakes and ponds

of this type occupy are the result of underground solution of limestone with the formation of subterranean caverns, the roofs of which

become weakened and fall in, causing depressions at the surface. The

process by which they were formed is in operation at the present

time, and sinks have formed since the settlement of these regions. They vary in size from ponds from 100 to 200 feet in diameter to

lakes of an area of as much as six square miles. The shallow ponds

often become dry and the water level in the larger and deeper ponds varies considerably with the seasons. Some attain considerable depth,

and are connected by open passages with underground channels, an

example of which is the Lime-sink, Forest Falls, eight miles north

of Whigham, Grady County. "\.. small stream flows into this sink,

which is about 90 feet deep, and disappears through an opening in the

bottom.

The most notable of the larger lakes are Ocean Pond and Long

Pond in Lowndes County, Original Pond, three miles west of :Met-

calf, and Rock Pond, near Camilla, Mitchell County.

Tlre second class represent depressions in level sandy plains.

These are usually shallow ponds of small area and most of them con-

tain a growth of cypress and gum. They are dependent upon seep-

age and become dry, with a few exceptions, in times of severe drought. They are numerous in the southeastern part of the Altamaha upland,

are typically developed on the Okefenokee plain, and also apl?ear on

the Satilla marine terrace plain 20 to 40 feet above sea level. It is

probable that these ponds for the most part occupy shallow depressions

which were present on the plains when they were first uplifted and became land surface, there, as yet, not having been sufficient subaerial

erosion to efface them. There are also a number of untimbered expanses of water in the

Okefenokee Swamp which are termed "lakes." (See map opposite

page 44.)

.

The third class represent abandoned channels of rivers and occur

in river :flood-plains. This is the type of lake so extensively devel-

oped along the lower course of the Mississippi. They are in the form

of ox-bows, or are .elongated, rarely circular; their water is usually

PHYSIOGRAPHY

43

affected by high water or overflow of the rivers along which they occur and is less clear than that of the lime-sink lakes and ponds. They may be connected with the river or their mouths may be silted up entirely, depending upon how recently they have been formed, but they are all subject to overflow during flood stages of the rivers. Hershman Lake in Screven County and Black Lake in Wilkinson County are the best examples of this type. Other lakes occur along the lower courses of the Oconee and Altamaha.

FLUVIATILE AND UPLAND SWAMPS
The fresh water swamps of considerable areas are of two types: fluviatile swamps and upland plain swamps. The latter appear along the coastal belt and owe their existence to the flatness and consequent imperfect drainage of the land surface. They are upland in that they lie at a higher level than the river swamps, and also in comparison with the river tide-swamp and the salt marshes although they may not be more than 20 feet above sea level. Okefenokee Swamp is a large upland swamp.
Nearly all of the streams of the Coastal Plain, even the small branches, are bordered by swamps. The most extensive are those bordering the large rivers of the first class. The swamp land lies only a few feet above the rivers and the frequent overflows maintain it in a swampy condition. Along the lower part of Savannah River the swamp reaches a width of five or six miles; it is densely wooded with a growth of oak, ash, cypress, gum, and pine. There are also broad swamp areas along the Ogeechee, Altamaha, Oconee, Ocmulgee, . and upper part of the Flint; the Chattahoochee forms an exception since there is scarcely any land along its course in Georgia which could be termed swamp.
The small branches, creeks, and rivers flow through broad, densely wooded lowlands, very often spreading out through the trees until it is difficult to determine just where the channel proper is located, and in places necessitating low bridges or a succession of bridges onefourth to one mile in length to effect a safe road crossing. Swamps 'of such character ar~ notable along Ogeechee River, Williamson's Swamp Creek, in Jefferson County; Commissioner's Creek, in Wilkinson County; and along the head waters of Little and Allapaha rivers in Tift, Irwin, and Berrien counties.
The amount of fluviatile or river and creek flood-plain swamp amounts to perhaps 1,000 square miles1 in the Georgia Coastal Plain.
1No complete survey of the swamp land of Georgia has been made, and the figures are only a rough estimate based on a knowledge of the approximate widths of the swamp a.long the largest rivers and creeks.

44

GEOLOGY OF THE COASTAL PLAIN

This land lies generally form two to eight feet above mean stages of water.

THE OKEFENOKEE SWAMP.

The Okefenokee Swamp is perhaps the greatest natural wonder in

the State. It lies in the southeastern part of the Coastal Plain, em-

braces parts of Ware, Charlton, and Clinch counties, and extends to

the Florida miles, and

line. It an area

has a length of of between 700

about and

40 800

msiqleus~rea

width miles.

of 30 The

swamp has been fully explored by hunters and lumbermen, but no

very extended descriptions of it have been published. The following

excellent short description is that of Dr. R. H. Loughridge," who was

one of a party that made a partial survey of the swamp in 1875:

This swamp (Okefenokee) has a width of 30 and a length of 40 miles, covering an area of about 500,000 acres. It is in reality an upland swamp, having an altitude of 120 feet above tidewater on .St. Mary's River. A sand rklge (part of the water divide of the State) 30 feet above the swamp extends along its eastern border to the South, becoming lower as it reaches the southern horseshoe bend of St. Mary's River. The swamp is highest on the northeast, and falls irregularly to the south and southwest from 12672 to 11172 feet at Ellicott's mound and on the southwestern corner.
The eastern part, 12 miles in width, is an open "prairie" or marsh, largely covered with water, in which are long rushes and water-lillies. Under its surface is a dense body of moss from four to six feet thick, the great mass of which is decayed, forming muck and peat. It is so derise that it will readily bear up a man's weight, merely sinking a little and rising for many feet around; hence the name of Okefenokee-"trembling earth." Small islands, covered with clumps of cypress, bay, and cassino, frequently occur. The
western part of the swamp is mostly covered by cypress trees and a dense growth similar to that of the small swamps outside, so tied together by bamboo briers and vines as to be impenetrable except by slow and terious cutting away with bush knives. Small open marshes, and also a number of large islands, are found throughout this region. These islands are quite level, but are slightly elevated above the swamp lands, and have a sandy soil, with an open timber growth of long-leaf pine and a very low undergrowth of sa.wpalmetto, and are similar in every respect to the mainland. Their dimensions are three or four miles by from one to two, and they are bordered by a low hammock land, on which there is a growth of magnolia, oak, etc. Hunters find deer and bear on thes3 islands. The soil or bottom of the swamp
proper seems to be but little else than white sand.

Dr. R. M. Harper has lately published a description in"which the literature and history of exploration is summarized, the geography,vegetation, etc., of the swamp are briefly set forth, and illustrations from several photographs taken in the swamp are given.
Such a phenomenon as the Okefenokee Swamp can not be passed over without offering some explanation of its existence. The following relating to its origin is quoted from Dr. Harper's paper:

Immediately east of the Okefinokee is one of the most interesting topographic features of the region, which would scarcely be noticeable but for the

'Tenth Census, Vol. VI, Cotton Production of Georgia, p. 51. 2Pop. Sci. Monthly, June, 1909.

F

L

0

R

I

D

R I DA

N

IC:O::ec::E:c5ia:::e:c::Jei:O=:::=:=====':i0:=:=:=:=:=:=:i'2iiif0 MILES
MAP OF OKEFENOKEE SWAMP AND ADJACENT REGION. BY OTTO V'EATCH.
The map has been compiled from a map of Okefenokee Swamp, by M. T. Singleton; from the map of Georgia, by A. G. Butts, published 1890; from the soil map of the
Waycross area, by the U. s. Bureau of Soils; and from notes by the author. The :ligures refer to elevations above sea-level.

PHYSIOGRAPHY

45.

general flatness of the country. It is a broad low ridge, exactly parallel with the coast and just about forty miles distant from it. This ridge has been traced by the writer from a few miles west of Jesup southward into the great bend of the St. Mary's River, and about thirty miles into Florida, where it is known as the "Trail Ridge," and happens to coincide in part with the Atlantic and Gulf divide and with the eastern boundary of Baker and Bradford Counties, though still maintaining its parellelism with the Atlantic coast. It is not an important divide in Georgia, though no streams intersect it between the St. Mary's and the Altamaha except the Satilla and Little Satilla Rivers.
At Camp Cornelia, where the old drainage ditch of the Suwanee Canal Company cuts through it, this remarkable ridge is about two miles wide and only about forty feet high; and it probably keeps practically the same dimension for many miles north and south. Its slopes are so gentle as to be scarcely noticeable to a person passing over it, but when viewed from a point a few miles away on one of the straight railroads which cross it, it stands out quite conspicuous.
"Trail Ridge, or Okefinokee Ridge, as the Georgia end of it might be called, does not belong to the class of cuestas or inland-facing escarpments which can be seen in many places in the upper half of the coastal plain, for it slopes equally on both sides and has no stream hugging its inland edge as far as known. Moreover (t is too smooth and too straight to have been formed by erosion. The same reasonable explanation of it would seem to be that it marks a comparatively recent slight flexure of the earth's crust, formed during one of the oscillations which the coastal plain experienced several times during its making. There seems to be a similar though smaller ridge about fifteen miles east of it, but so little is known about that that it could not be mapped at the present time. Mount Pleasant and Waynesville. near the boundary between Wayne and Glynn counties, are located on the latter ridge and along its summit was one of the principal ro:;tds from Savannah to East Florida a century ago, followed by Bartram and other travelers.
The internal structure of the Okefinokee Ridge is not its least interesting feature. In the big ditch at Camp Cornelia, as well as at the crossings of four railroads (three of tliem shown on the map and one a little farther north), there occurs beneath a few feet of white sand a chocolate-colored or almost black material of unknown depth known locally as "hardpan." No analysis of the hardpan is available, but when pulverized in the fingers it feels like nothing but sand. Its dark color is doubtless due to vegetable matter, -with a little cement of iron oxide or bog iron ore, which makes it so hard in the mass that dynamite was used in removing it, it is said. No recognizable organic remains were noticed in it, but a faint horizontal stratification could be detected. The aspect of the hardpan is so similar to that of the subsoil of existing salt marshes that its origin is not hard to guess.
Although this peculiar formation may not be confined to the Okefinokee Ridge, its extent is evidently limited; for in railroad cuts around Waycross and Folkston and in Camden county and elsewhere the ordinary reddish Pliocene loam can be seen near the surface, without any signs of the black hardpan. The hardpan was doubtless formed in some prehistoric swamp or marsh occupying a somewhat larger area than Okefinokee does now-perhaps the Suwanee Straight of geologists, which is supposed to have separated Florida from the mainland in Miocene times. It seems to have no effect on the vegetation above it, which is just like that of the ordinary flat pine-
barrens underlaid by the loam. Assuming the foregoing theories to be true we can now trace the probable
development of Okefinokee Swamp. When the ridge was thrown up across the shallow trough which had been suwanee Strait it naturally created a. basin behind it, which must have quickly filled with water, forming a large, shallow lake. This lake then began to fill with vegetation, as many other

46

GEOLOGY OF THE COASTAL PLAIN

shallow lakes then began in temperate regions are doing,

and gradually took on the aspect it has to-day, which will

be described more in detail below, under the head of vegetation. A glance at the map will show how the waters are darned up by the ridge, the straight eastern 'border con-

e~ o

~

'"''" ":E
1![11 g'

~~/i!i,;

trasting with the very irregular .western iborder of the sw;amp.
The notes of the writer on the geology of the region and its physiographic history differ somewhat from the views advanced in the preceding quotation.

!,'~I::i;ij'

~<.~"a,,.'l/:i:/:!1~1I,:,1I,1
:~:'1/11 ,

:1
i"f'

It is believed that the swamp lies upon a terrace plain, of probable marine origin, parallel to a lower

~>i

~.i:l
!i! surveyorsCreek

terrace plain, which lies from 15 to 40 feet above .... ); w 116

sea-level, and extends to the present coast. The @

western edge of the lower plain is marked by an es- ~
<Carpment which is prominent at Waynesville, l\lt. S

Pleasant, Folkston,

Walthourville, and a few miles east of and probably represents the shore-line of

"~ '

the latest Pleistocene sea. The next higher plain, Ci)

the Okefenokee Plain, extends parallel to the lower, S

and from the above mentioned escarpment extends 20 Q to 40 miles westward. The western extent of the ~

plain is not distinctly marked (although a good topo- ~

graphic map would probably reveal it), but it is be-

P>
1:::1

lieved that it is a line approximately from Olyo in : Effingham County, southwestward to near Groveland, ~

1120'

thence to Jesup, Offerman, and Waycross and thence ,p

:ii St!nd ridge
~: 140'

- follows the northern and western borders of Okefeno-
kee Swamp. There is a low sand ridge on the east side of the swamp, which has acted, to some extent, as a dam to the drainage from the west.

"' ~

Spani..sh Creek-

Ltule 0/sef'enokee

~ !![ ~-:,amp

~ ~~ 1:1:r satilla

The swamp does not occupy a single large depres-

> : to 11l escarpment SarUlalUver

sion or basin, since elevations show that the northern I

edge is 15 feet higher than the southeastern corner, ~

and there are also differences of elevation of the sur P'

face within the swamp. The swamp conforms, in

general to the southeastward tilt of the plain upon

which it is located. The land now occupied by the

swamp was so flat, that the rainfall was not readily

removed and hence accumulated as broad sheets of

water, which vegetation converted into swamps. The

presence of islands in the swamp which are reported

to be very similar in soil and tree growth to the dry

land adjacent, together with the fact that creek run-

ways still exist within the swamp, is v~ry suggestive

that the swamp area did not differ materially from

the land to the north and west and that the Okefeno-

kee was formed by the gradual accumulation of water and consequent aquatic vegetation. The "bays" or entrants of swamp into the dry land, along the

1"'1 Cumberland Island

courses of tributary creeks, have produced the ragged

PHYSIOGRAPHY

47

or irregular north and west boundaries and indicate the process by which the swamp has increased in area, namely by the enlargement and union of creek swamps and final obliteration of the streani channels. Should there be a period of a number of years with the precipitation even slightly above the present normal the whole area northwest of the swamp to the Atlantic Coast Line Railroad and beyond would be incorporated as a part of the Okefenokee. This area is at present formed of flat, ill-drained islands surrounded by narrow strips of swamp.
The swamp then owes its existence to the general flatness of the original land surface which has been lifted above sea level without deformation. The sand ridge on the east, although acting as a dam for a part of the drainage, was a subordinate agent in producing the swamp, as is in a measure proved by the absence of any conspicuous ridge or barriers on the south and southeast, and especially by the differences in elevations of various parts of the surface of the swamp. As for example, the elevation at the point where Cypress Creek issues on the western side is lll2 feet, while at a point half way between this and St. Marys River the elevation is 118lj2 feet, and the point where the St. Marys issues on the southeastern corner is 1111f2 feet. If the existence of the swamp depended entirely upon the barrier ridge on the east the level o:f the western margin of the swamp should be higher than the intermediate levels between the western and eastern margins. This is not true according to known elevations.

Fig. 4.-Profile from Okerenokee Swamp to Kings Ferry, Florida, along line D-E, on map of Okefenokee Swamp.
The geologic formations adjacent to the swamp are late Tertiary, Pleistocence, and Recent. The Alum Bluff formation (upper Oligo-
n cene) consisting of greenish, sandy clays, and overlain by a small
thickness of Altamaha (Lafayette and surficial sand, occurs to the north and west, and very probably underlies the swamp. As inferred from the record of a well at Waycross, it is about 300 feet in depth to a limestone formation.
The Altamaha (Lafayette'?) formation is typically exposed in cuts and excavations near Waycross, and probably also occurs east of the swamp. This formation is composed of red, argillaceous sand and sandy clay. To the east of the swamp the plain is covered by gray

48

GEOLOGY OF THE COASTAL PLAIN

and yellowish or brownish, incoherent quartz sand, varying :from two or three to 15 or 20 :feet in thickness. This sand :foitrns the sand ridge on the east side o:f the swamp. It is considered a Pleistocene deposit. Beneath the surficial sand there is a small thickness, not exceeding 40 or 50 :feet, o:f red, argillaceous sand and bluish clay, Pliocene or Pleistocene in age. Fossiliferous- beds o:f white, argillaceous limestone and greenish or drab laminated clay, probably Pliocene or Pleistocene, and older than the surficial sand, occur in the banks o:f St. Marys and Satilla rivers a :few :feet above sea level.
So :far as known, the deposits in the swamp are white sand and recent vegetable or semi-peaty accumulations. White or gray sand occurs on the edges o:f the swamp and only sand is exposed in the old drainage ditch constructed by the Suwanee Canal Company, near Trader's Hill. Fishermen and hunters report white sand in the bottoms o:f some o:f the lakes. Peaty accumulations three or :four :feet thick are reported, and these organic accumulations are known to have been fired :from nearby :forest fires during periods o:f drought.
There is no evidence in the many exposures o:f strata examined in Charlton, Ware and Camden counties, that any considerable flexures or :folds exist in this part o:f the State. The escarpment a :few miles east o:f the swamp, which suggests the limb o:f an anticlinal :fold, is believed to be a Pleistocene erosion :feature, as stated above.

TABLE OF GEOLOGIC FOR:\IATIONS NEAR OKEFENOKEE S\VAMP

Recent:

Peaty muck in the Okefenokee Swamp.

Pleistocene and Pliocene ( ?)

Satilla formation--clay terraces or flatwoods bordering St. Marys

and Satilla rivers.

Okefenokee formation-surficial white sand, and perhaps some

red sand and mud, the latter occupying the sites of ancient

estuaries or shallow bays.

Altamaha (Lafayette ?)-red, argillaceous sand, typically devel-

oped at Waycross.

Charlton formation-fossiliferous limestonE) and clay on St.

Marys River.

Miocene.

Probable occurrence at Owens Ferry, Satilla River.

Miocene strata are also known' near Jacksonville, Fla.

Oligocene (Alum Bluff).



Sandy, greenish, and drab clays of the Alum Bluff formation,

ov'-rlain by a small thickness of A,tamaha (Lafayette ?') and

surficial sand, occur on the north and west sides of the swamp.

There are numbers o:f smaller swampy areas in the Okefenokee
Plain. Some o:f these are merely broad, undrained flats, due, perhaps, to original ineq~alities in the land sur:face and are Oke:fenokees

'Matson and Clapp. Fla. Geol. Survey, Second Annual Report; 1909, P- 108.

GEOLOGY OF 1'HE OOASTAJ~ PLAiN OF' GEORG/.-1..

PLATE Ill.

HILL ON EA T IDE OF LITTLE OCMULGEE RIVER, TWO MILES NORTHEAST OF HELENA, TELFAIR COUNTL
B. A LilliE l~K POND K:->OW AS WAVI:->G PO:->D. SEVE, Ol~ YLVESTER, WORTH CO NTY .

PHYSIOGRAPHY

49

on a small scale. The general slope of the plain eastward is perhap~
not more than two feet per mile, and poor natural drainage is readily inferred.

OTHER SWAMPS
There are also swamp areas in the lower coastal terrace plain which lie 15 to 25 feet above sea level. These have the appearance of being the sites of ancient lagoons or shallow sounds. Buffalo Swamp in the western part of Glynn County is an example. This swamp extends from Altamaha River southward to Turtle River and has a much greater length than width. It contains clay and is slightly lower than the sandy pine and palmetto land on both sides. Oyster shells in the clay bear evidence of its marine origin. Cabbage palmetto trees occur near Bladen and Everett, and are possibly a survival from the period when this area was a sound or marsh. It is often entirely covered with water during the rainy seasons but becomes almost dry in times of drought. Should the present coast be elevated 20 or 30 feet the waterways and marsh between St. Simon Island and the mainland would probably be the site of such a swamp area as Buffalo Swamp.
The Big Pond, located seven miles north of Baxley, Appling County, is worthy of special mention here. Although this tract is locally termed "pond," it is a misnomer, as it is more properly a swamp. The only open water is a small lake in the interior, reported to be not more than 100 yards long, whereas in the area as a whole there is a thick growth of cypress, gum, and pine, with an undergrowth of small trees and bushes. (See plate IV, A.) Big Pond lies upon a flat, sandy, pine-covered plain, at an elevation about 200 feet . above sea level. It has an area, including a small swamp, known as ''Second Pond," of about eight square miles. The two "ponds" are connected by a narrow swamp known as Tiger Bay. On the east side of the swamps there is a low ridge covered with superficial gray sand that reaches a thickness of about 10 feet. Ten-Mile Creek, a small tributary of Altamaha River, flows sluggishly from the southern end of Big Pond.
Big Pond belongs to the upland, non-alluvial c]ass of swamps, and is probably somewhat similar in origin to Okefenokee Swamp and to the smaller cypress and gum ponds which are so numerous in the southeastern part of the Coastal Plain.

SPRINGS
There are a few large springs of physiographic and geologic interest. These springs are in limestone areas and, as they appear to

50

GEOLOGY OF THE COASTAL PLAIN

be c~nnected with subter~anean streams, many o them may be

descnbed as natural artesian wells. The water is clear and very

transparent, usually has a deceptive, faint affected by rains, and evidently comes rom

bluish great

dceopltohr~.

is

but The

little larg-

est o these springs is Blue Spring, 6ur miles south o Albany. The

water at this place rises under considerable pressure through a roughly

circular opening in limestone, and has an enormous flow. 1

Similar springs are: Blue or Wade Spring, seven miles east o Quit-

man; Mcintyre Spring on the \Vithlacoochee near the Florida line;

Blue or Russell Spring o Decatur County; Well, Wilkes, and Rock

springs o Laurens County, and :Magnolia Spring o Jenkins County.

These are all large springs rising through limestone caverns.

Small, both permanent and intermittent springs, o only mmor

importance, are numerous except along the coastal lowlands.

ELEVATIONS

BY OTTO VEATCH
In the general absence o topographic maps, g1vmg accurate elevations in the Coastal Plain, it is believed that the compilations here given will be o interest and o practical value in working out geologic problems and in the study o underground waters.
The following list o elevations has been compiled chiefly rom: Dictionary o Altitudes in the United States, by Henry Gannett, Bulletin No. 274 o the U. S. Geological Survey; rom the list o elevations given in the report on the Water Powers o Georgia, Bulletin No. 3-A o the Geological Survey o Georgia; rom the reports o the U. S. Army Engineers on the surveys o Ocmulgee, Oconee, Altamaha, and Savannah rivers; and rom the Columbus, Talbotton, and Mil~ ledgeville topographic sheets o the U. S. Geological Survey. Several o the elevations given are merely rough estim~tes or guesses based on other elevations and upon knowledge o the topography by the author, in a few instances supported by aneroid barometer readings. In some o the figures given in this compilation there may
be errors o even several feet, but, notwithstanding, these elevations are better than none at all, and the errors are not so great but that the data may be useful i"n the study o physiography, geology, and artesian
waters.
1Discharge measurements by B. M. and M. R. Hall (U. S. Geological Survey, Water Supply and Irrigation Paper. No. 197, page 236) varied from 26.4 second-feet to 135 second-feet. This is approximately 18,000,000 to 87,000,000 ga\lons per 24 honrs. This is the largest spring in the State.

ELEVA.TIONS

51

Tbtl abbreviations used are: A. B. & A.-Atlanta, Birmingham & Atlantic Railroad. A. 0. L.-Atlantic Coast Line Railroad. 0. of Ga.~Oentral of Georgia Railway. Ga. R R.-Georgia Railroad. G. S. & F.-Georgia Southern & Florida Railway. L. & N.-Louisville & Nashville Railroad. M. D. & S.-:J\acon, Dublin & Savannah R.ailroad. S. A. L.-Seaboard Air Line Railway. U.S. A. Eng.-United States Army Engineers. U.S. G. S.-United States Geological Survey.

Abbeville . . . . . . . . . . . . . . Rough estimate

. 225 ?

Abbeville, low water, R. R. bridge . . U. S. A. Eng .

. 169.33

Achord ........ .

. U.S. G. S . . .

. 274

Acree, Dougherty County

. A. C. L. R. R ..

. 205

Adams Park ..... .

. U. S. G. S. . .

. 259

Adel . . . . . . . . . . .

. G. S. & F. Ry.

. 246

Adrian, Emanuel County

. Rough estimate

. 290 ?

Albany ......... .

. C. of Ga. Rwy .

. 184

Albany, Flint River level

A. C. L. R. R .

. 127

Allapaha ...... .

. A. C. L. R. R . .

. 293

Alexanderville . . . .

. A. C. L. R. R . .

. 153

Allentown ...... .

. M. D. & S. R. R .

. 411 ?

Ambrose, Coffee County

. A. B. & A. R. R. .

. 395

Americus ..

. C. of Ga. Rwy .

. 360

Andersonville

. C. of Ga. Rwy .

. 394

Arabi ...

. G. S. & F. Ry.

. 460

Argyle . . .

. A. C. L. R. R . .

. 161

Armena .. .

. S. A. L. Ry. . .

. 275 ?

Ashburn . . . . . . .

. G. S. & F. Ry. .

. 450

Augusta, Union Station .

. City Engineer .

. 143

Augusta, River gage .

. 'Weather Bureau

. 100

Baconton ...... .

. A. C. L. R. R .

. 160

Bainbridge . . . . . .

. A. C. L. R. R .

. 110

Bainbridge, river level

Rough estimate

. 80

Bartow ....... .

C. of Ga. Rwy

. 237 ?

Bath, Richmond County

. Rough estimate

. 80

Baxley ..

. U. S. G. S. .

. 206

Belair ...

. Ga. R. R. . . .

. 295

Berzelia ..

. Ga. R. R. . .

. 488

Blackshear

. A. C. L. R. R.

. 106

Bladen . .

. S. A. L. Ry. .

. 22

Blakely ..

Rough estimate . . . . . . 275

Blakely ..

. Weather Bureau . . . . . . . 300

Bloomingda]e

. C. of Ga. Rwy. .

. 24

Bonaire .. .

. G. S. & F. Ry. .

. 354

Boston . . . . .

. A. C. L. R. R. .

. 194

Bostwick (Paschal)

. C. of Ga. Rwy.

. 669

Boulogne, Florida .

. A. C. L. R. R.

. 70

Box Springs . . . .

. U. S. G. S.

. 364

Braganza .... .

. A. C. L. R. R. .

144

Brentwood . . . . . .

. U. S. G. S. . .

. 167

Brewer (Tusculum P. 0.)

. C. of Ga. Rwy.

. 118

Brooklyn ....... .

. S. A. L. Ry. . .

. 691

52

GEOLOGY OF THE COASTAL PLAIN

Brinson

Brunswick ..

Brunswick (City Hall)

Buena Vista .

Bullards . . . .

Burroughs

Bushnell . . .

Butler

Byromville . .

Byron

Cairo ...

Camak

Cameron .

Camilla ..

Carrs Station .

Cecil ..

Chauncey

Chula .

Claxton

Clifton

Climax

Clyo

Cochran

Coleman

Coley

Collins

Colon

Columbus, Union Station .

Columbus, river level

Cordele Crescent .

...

Culverton

Cusseta

Cuthbert

Cutler ..

Cl.lyler . . . .

Cycloneter . . . . . . . . . .

Dakota

Darien

Dasher

Davis

Davisboro

Dawson .

Dearing .

Devereux

Dewitt

Dixie

.

Dock Junction

Doctortown

Doctortown, low water level .

Donaldsonville

Douglas ...

Doublerun

Dover ...

Dry Branch ..

Dublin . . ..

. A. C. L. R. R. . . Sou. Rwy.
U.S. G. S. . Rough estimate
U.S. G. S. . . . . A. C. L. R. R. . . A. B. & A. R. R. . C. of Ga. Rwy. .
. A. B. & A. R. R. . C. of Ga. Rwy. . . A. C. L. R. R. . . Ga. R. R. . C. of Ga. Rwy.
. A. C. L. R. R. . U.S. G. S. . . G. S. & F. Ry.
. U.S. G. S. . . . G. S. & F. Ry. . S. A. L. Ry. . . C. of Ga. Rwy. . A. C. L. R. R .. . S. A. L. Ry. .
. U.S. G. S. . . . C. of Ga. Rwy. . Sou. Rwy. . S. A. L. Ry. . . G. S. & F. Ry. . C. of Ga. Rwy. . U.S. G. S. . . . G. S. & F. Ry. . Rough estimate
. Ga. R. R. . S. A. L. Ry. . . C. of Ga. Rwy. .G. S. & F. Ry. . S. A. L. Ry. . .G. S. & F. Ry. . G. S. & F. Ry. . Rough estimate . G. S. & F. Ry.
.A. C. L. R. R.
. C. of Ga. Rwy. . C. of Ga. Rwy. . Ga. R. R.
. U. S. G. S. B. :\1. . Butt's map .....
. A. C. L. R. R.
. U.S. G. S. . A. C. L. R. R: . . U. S. A. Eng.
. A. C. L. R. R. . . A. B. & A. R. R.
. A. B. & A. R. R. . C. of Ga. Rwy. .
. M. D. & S. R. R. . M. D. & S. R. R.

. 104
. 13 .11 . 590 . 259 . 19 . 385 ? . 650 . 365 ? . 515 . 237 . 578 . 103 . 167 . 500 250 . 300 . 395 . 194 ? . 22 . 277 . 74 . 342 . 391
. 303 . 23R . 137 . 260 . 200 . 336 . 18
. 549 . 540 . 446 . 78 37 ? . 410 . 410 . 15 . 185 . 238 . 302 . 352 . 464 . 577 . 175 . 130 . 25 . 74 . 31.72 . 139 . 388 ? 363 ? . 104 . 368 ? . 2311 ?

1Elevations on the M. D. & S. R. R. are taken from the Jist given in Water-Powers of Georgia, Geol. Survey of Ga., Bull 3-A, pp, 98-100. Rough corrections were made according to the benchmark established on the Oconee River at Dublin by U. S. Army Engineers.

ELEVATIONS

Dublin, low water level

. U. S. A. Eng. .

Dudley . . .

. M. D. & S. R. R.

Dupont . . . . . . . .

. A. C. L. R. R.

East Albany . . . . .

. A. C. L. R. R.

Eastman . . . . . . . . .

. U. S. G . S. . .

Eden . . . . . . . . . . .

. C. of Ga. Rwy.

Egypt . . . . . . . . . . .

. C. of Ga. Rwy.

Eldorado . . . . . . . .

. . G. S. & F. Ry.

Elko . . . . . . . . . . . . . . . . . . G. S. & F. Ry.

Ellabelle . . . . . . . . . .

. . S. A. L. Ry. .

Ellaville . . . . . . . . . . .

. . J. W. Spencer

Empire . . . . . . . . . . .

. U. S. G. S. . .

Esquiline . . . . . . . . .

. . U. S. G. S. .

Eufaula, Alabama . . . . . .

. . C. of Ga. Rwy.

Everett City . . . . . . . . . . . . . U. S. G. S. . . .

Everett Station, Crawford County . . C. of Ga. Rwy.

Everett Station, Flint River, railroad

bridge

. C. of Ga. Rwy.

Exeter

. A. C. L. R. R.

Exley . . . .

. . . S. A. L. Ry. .

Faceville

. . . A. C. L. R. R.

Fargo

. . G. S. & F. Ry.

Fitzgerald . . . .

'. . A. B. & A. R. R.

Fitzpatrick

. M. D. & S. R. R.

Fleming . . . . . .

. A. C. L. R. R.

Flint . . . . . . . .

. A. C. L. R. R.

Folkston . . . . . . . . . . .

. A. C. L. R. R.

Fort Gaines . . . . . . . . . . . C. of Ga. Rwy.

Fort Gaines, river level, low water . . . . . . . . .

Fort Mudge . . .

. A. C. L. R. R.

Fort Valley . . .

. C. of Ga. Rwy.

Fowltown . .

A. C. L. R. R.

Gallemore (Willis P. 0.)

. M. D. & S. R. R.

Gardi . . . . . .

. U. S. G. S. . . .

Geneva (station)

. U. S. G. S. . . .

Georgetown . . .

. . . . . . C. of Ga. Rwy. .

Georgetown, low water, Chattahoochee

.

River . . . . . . . . . . . . . Rough estimate

Glenmore . . . . . . . . . . . . . A. C. L. R. R.

Godwinville . . .

. U. S. G. S. . .

Gordon . . . . .

. .

. C. of Ga. Rwy.

Gordon, Alabama . . . . . . .

. A. C. L. R. R.

Graham . . . . . . . . . . . .

. Sou. Rwy.

Graves

. . . . . . . . . .

. C. of Ga. Rwy.

Greens Cut . . . . . . . . . .

. C. of Ga. Rwy.

Griswold . . . . . . . . . . .

. C. of Ga. Rwy.

Grovania . . . . . .

. G. S. & F. Ry.

Groveland . . . . . .

. S. A. L. Ry. .

Grovetown . . . . .

. Ga. R. R. . . .

Guyton . . . . . . .

. C. of Ga. Rwy.

Hagan . . . . , . . . . .

. S. A. L. Ry. .

Hahira

. G. S. & F. Ry.

Halcyondale . . . . . . .

. C. of Ga. Rwy.

Halloca . . . . . . . . .

. U. S. G. S.

Hardaway . . . . . . . . .

. A. C. L. R. R.

Hardeeville, S. C. . . . . . .

A. C. L. R. R.

Harlem . . . . . . . . . . .

. Ga. R. R.

Hatcher . . . . . . . . . . .

. C. of Ga. Rwy. .

Hawkinsville . . . . . . . . .

. Weather Bureau

53

. 160.6

. 325 ?

. 180

. 186

. 357

34



. .

132 340

. 443

93 ?

. 591

. 382

. 300

. 211 ?

16

. 362

. 337 94 63
. 296 . 116 : . 388 ? . 541 ?
22 . 168
80 . 163 . 100 ? . 134 . 522 . 289 . 394 ?
62
. 581 . 189

. 111 ? . 151 . 312 . 348 . 160 . 240 . 350 . 284 . 447 444 . 162 ? . 495
81
. 186 ? . 230 . 110 . 323 . 183
21 .548 . 289 ? . 235

54

GEOLOGY OF THE COASTAL PLAIN

Hawkinsville, low water level

. U. S. A. Eng. .

. 200.2

Haylow . . . . . . . . . .

. G. S. & F. Ry.

. 167

Hazlehurst . . . . . . . . .

. U. S. G. S. . .

256

Helena . . . . . . . . . . .

. U. S. G. S. . .

. 247

Hephzibah . . . . . . . . . .

.Weather Bureau

. 402

Herndon . . . . . . . . .

. C. of Ga. Rwy.

. 179

Homerville .

. . . A. C. L. R. R. .

. 176

Howard . . . . . . . . . . . . . . C. of Ga. Rwy.

. 666 ?

Howell . . . . . . . . . . . . . . . G. S. & F. Ry.

. 169

Irwinton . . . . . . . . . . . . . . .Rough estimate

460 ?

Isabella (Sylvester)

. A. C. L. R. R.

. 370

Jasper, Florida .

. A. C. L. R. R. .

. 152

Jeffersonville

. M. D. & S. R. R.

. 526

Jennings, Florida .

. G. S. & F. Ry. .

. 150

Jesup . . . . . . . . . . .. . .

. U. S. G. S. .

. 100

Johnsonville, Jeff Davis County

. Sou. Rwy. .

240

Juniper Station

. U. S. G. S. . .

. 422

Kathleen .

G. S. & F. Ry. .

. 330

Kingsland .

S. A. L. Ry. .

. 41

Kirkland .

A. C. L. R. R.

. 200 .

Knoxville .

J ..E. Thomas .

640

Lake Park

G. S. & F. Ry.

. 160

Lawton .

C. of Ga. Rwy.

. 225

Leesburg

Rough estimate

. 300 ?

Lenox . . .

. G. S. & F. Ry.

. 300

Lewiston

C. of Ga. Rwy.

. 385

Lily . . . .

. A. B. & A. R. R.

. 364 ?

Long~treet

. U. S. G. S. . . .

. 302

Louisville . . . . . . .

Weather Bureau

259

Ludowici . . . . . . . .

. A. C. L. R. R. .

71

Lulaton . . . . . . . . .

Rough estimate .

. 50

Lumber City . . . . . . . . . . . . U. S. G. S. . . . . . . 146

Lumber City, river level, low water . U. S. A. Eng. . . . . . . . . 84.7

Lumpkin (station)

Rough estimate

. 500

Lumpkin

. Weather Bureau

. 650

Lyons . . . . . .

S. A. L. Ry. .

. 254

McBean Station .

. C. of Ga. Rwy.

. 134 ?

McClenny, Florida

. S. A. L. Ry. .

. 125

McDonald .

. . A. C. L. R. R.

. 167

McGriff . . . . . .

. . U. S. G. S. . .

. 259

Mcintosh . . . . .

. . . . . A. C. L. R. R.

. 22

McRae . . . . . . . . . . . . . . . .U. S. G. S. . . .

. 230

Mcintyre . . . . . . . . . . . . C. of Ga. Rwy. .

. 261

Macon, Union Station . . . . .

. G. S. & F. Ry.

. 334

Macon, near Sou. Rwy. Station .

. U. S. G. S. . .

311

Macon, low water level

. U. S. A. Eng. .

. 279.02

Macon Junction

C. of .Ga. Rwy.

. 350

Manassas

S. A. L. Ry. .

. 217

Marshallville

C. of Ga. Rwy.

. 500

Marlow

C. of Ga. Rwy.

. 72

Mayday . . .

G. S. & F. Ry.

. 140

Mayfield . . . . . . . . . .

Ga. R. R.

417. I>

Meigs . . .

A. C. L. R. R.

341

Meinhard .

S. A. L. Ry. .

19

Meldrim

C. of Ga. Rwy.

2!3

Melrose . .

G. S. & F. Ry.

154

Metcalf . .

. A. C. L. R. R.

170

Midville . .

. C. of Ga. Rwy.

186

Milledgeville . . . . . . . .

. Ga. R. R.

. 276

ELEVATIONS

Milledgeville, low water level . . . . U. S. A. Eng.

Millen . . . . . . . . . . . . . . . . C. of Ga. Rwy.

Millwood . . . . . . . . . . . . . . . A. C. L. R. R.

Mineola . . . . .

. . .

. G. S. & F. Ry.

Moniac . . . . . . . . . . .

G. S. & F. Ry.

Monteith . . . . . . . . .

. A. C. L. R. R.

Mlontezuma . . . . . . . .

. C. of Ga. Rwy.

Montrose . . . . . . . . .

. M. D. & S. R. R.

Morgan . . . . . . . . .

. ... Weather Bureau

Morris . . . . . . . . . .. . . . . . . C. of Ga. Rwy.

Mount Pleasant . . . . . . . . . . . Sou. Rwy.

Munnerlyn . . . . . . . . . . . . . . C. of Ga. Rwy.

Muscogee . . . . . . . .

. U. S. G. S. . .

Myers, Effingham County . . . . . . S. A. L. Ry.

Naylor . . . . . . . . . . . . . . . A. C. L. R. R.

Nicholls . . . . . . . . . . . . . . . A. B. & A. R. R.

Norwood . . . . . . . . . . . . . . .Ga. R. R. . . .

Ochillee . . . . . . . . . . . . . . U. S. G. S. . .

Ocklockonee . . . . . . . . . . . A. C. L. R. R.

Ochwalkee, low water Oconee R. . . . U. S. A. Eng.

Oconee . . .

. C. of Ga. Rwy.

Odum . . .

. U. S. G. S. . .

Offerman . . . . . . . . . . . .. . . A. C. L. R. R.

Ogeechee . . . . . . . . . .

. . C. of Ga. Rwy.

Oglethorpe . . .

. C. of Ga. Rwy.

Ohoopee . . . .

. S. A. L. Ry.

Oliver . . . . .

. C. of Ga. Rwy.

Omaha (station)

.Rough estimate

Ousley . . . .

. A. C. L. R. R. .

Paramore Hill

. C. of Ga. Rwy.

Parrott

. S. A. L. Ry. .

Paschal

. C. of Ga. Rwy.

Patterson

. A. C. L. R. R.

Pearson .

. A. C. L. R. R.

Pembroke .

. S. A. L. Ry. .

Pendarvis . .

U. S, G. S. . .

Pennick . . . .

. . U. S. G. S. . .

Pikes Peak (station)

.. M.D. & S. R. R.

Pinegrove . . . . . . . . . . . . . . U. S. G. S. . .

Pinehurst . . . . . . . . . . . . . G. S. & F. Ry.

Pineora . . . . . . . . . . . . . . C. of Ga. Rwy.

Plscola, Brooks County . . . . . . . Weather Bureau

Pooler . . .

. . . . C. of Ga. Rwy.

Poulan

. . . . . . . . . . . . . . A. C. L. R. R. .

Powersville . . . . . . . . .

. C. of Ga. Rwy. .

Quitman . . . . . . . . . . . . A .C. L. R. R. . .

Racepond . . . . . . . . . . . . . . A. C. L. R. R. .

Rebecca . . . . . . . . . . . . . . . . . A. B. & A. R. R.

Recovery . . . . . . . . . . . . . A. C. L. R. R. .

Register . . . . . . . . . . .

. Rough estimate

Renfroes

. S. A. L. Ry. .

Reynolds . . . . . . . . . . . . . C. of Ga. Rwy.

Riceboro . . . . . . . . . . . . . Rough estimate

Richland . . . . . : . . . . . . . . . S. A. L. Ry. .

Richwood . . . . . . .

. G. S. & F. Ry.

Rincon . . . . . . . . . . . . . S. A. L. Ry. .

River Junction, Florida .

. . L. & N. R. R. .

Roberta

. . . .

.Rough estimate

Roberts Station . . . . . . . . . . Ga. R. R. . . .

55
. 241.29 . 156 . 160 . 220 . 114 . 16
..3oo'
. 391 . 337 . 242 . 59 . 264 ? . 245 . 45 . 192 . 306 ? . 588 . 273
. 263 . 114.4 . 223 . 155 . 106 . 111 . 299
. " 187 . 140 . 240 . 148 . 235 . 482 669 . 104 205 . 101 85 . 18 534 229 . 390 78 . 19()
2:t
345. . 385. 173: 148 373 ?' .189 . 225 '!' 601 ? 43&
. 15
. 600 . 358 . 75 . 84 . 620 . 557.

56

GEOLOGY OF THE COASTAL PLAIN

Rockyford . . . . . . . . . . . . . . . c. of Ga. Rwy.

. 130

Rogers . . . . . . . . . .

C. of Ga. Rwy.

. 159

Saffold . . . . . . . . . . .

. A. C. L. R. R.

. 105

Saffold, level of Chatt. R . . . . . . Rough estimate

. 65

St. George

. . . G. S. & F. Ry.

. 78

St. Mary's . . . . . .

. . . . Rough estimate

. 12

Sandersville . . . . . . . . . . . . . Rough estimate

. 470

Satilla . . . . . . . . . . . . . . A. C, L. R. R.

. 96

Satilla, river level . . . . . . . . . . A. C. L. R. R.

. 71

Savannah . . . . . . . . .

. A. C. L. R. R. .

. 21

Scarboro . . . . . . . . .

. C. of Ga. Rwy.

. 147

Schlatterville . . . . . . .

. A. C. L. R. R.

. 133

Scotland . . . . . . . . .

. U. S. G. S. . .

. 142

Screven . . . . . . . . . .

. A. C. L. R. R. . . . . . . . 124

Shell Bluff Landing, Burke Co. . . U. S. A. Eng. (low water) . . 87

Shell Bluff Landing, Burke Co. . . U. S. A. Eng. (highest point) . 237

Shellman . . . . . . . . .

. C. of Ga. Rwy . .

. 379 ?

Sibley . . . . . . . . '. . . . . . . . G. S. .& F. Ry.

. 440

Smithville . . . . . . . . . . . . . . C. of Ga. Rwy.

. 332

Sofkee

. G. S. & F. Ry.

. 370

Soperton .

. Rough estimate

. 290

Sparks . .

. G. S. & F. Ry. .

. . . . . 241

Sparta

. Ga. R. R.

. . . . . . 557

Springfield

Rough estimate

. . . . . . 100

Statesboro . .

. ..

Rough estimate . . . . . 175 to 200

Sterling . . . . . . . . . . . . . . .. U. S. G. S. . .

. 21

Stillmore (highest land)

. Rough estimate

. 300

Stillwell, Effingham Co.

S. A. L. Ry. .

. 69

Stockton . . . . . . . . . . .

A. C. L. R. R. .

. 187

Sulphur Springs . . . . . . . . . U. S. G. S. . .

. 300

Sumner . . .

. A. C. L. R. R.

. 373

Sunhill . . . . . . . . . . . .

. C. of Ga. Rwy.

. 362

Surrency . . . . . . . . . . .

. U. S. G. S. . .

. 187

Swift Creek . . . . . . . . .

. M. D. & S. R. R.

. 324 ?

Sycamore . . . . . . . . . . .

. G. S. & F. Ry.

. 415

Sylvania ................Rough estimate

. 200

Sylvester

.

. . . A. C. L. R. R. .

. 370 ?

Talbotton

. . . . . . . . . . . . U. S. G. S. . .

. 726

Tarrytown . . . . . . . . . . . . . Rough estimate

. 290 ?

Tennille . . .

. . . . . C. of Ga. Rwy.

. 469

Thalman

. Rough estimate

. 20

Thelma

.

. . G. S. & F. Ry. .

. 158

Thomas . . .

. . . . . C. of Ga. Rwy.

. 285

Thomasville . . . . . . . . . . . . . A. C. L. Rwy.

. 250

Thomson . . . . . . . . . . . . . . . Ga. R. R. . . .

. . 503

Tifton . . . . . . . . . . . . . . . . A. C. L. R. R. .

. 370

Tivola . .

. . . G. S. & F. Ry.

. 300

Toomsboro . . . . . . . .

. . . . C. of Ga. Rwy.

Towns . . . . . . . . . . . . . . . U. S. G. S. . .

. 227
. 128

Tyty . . . . . . . . . . . . .

. A. C. L. R. R. .

. 332

Unadilla . . . . . . . . . . .

. G. S. & F. Ry.

. 412

Upatoi . . . . . . . . .

U. S. G. S. . .

. 418

Uptonville . . . . . . . . . .

. A. C. L. R. R. .

. 83

Valambrosa . . . . . . . . . .

. M, D. & S. R. R.

. 258 ?

Valdosta . . . . . . . . . . . . . . .. A. C. L. R. R. .

. 215

Valona, Mcintosh County . . Weather Bureau

. 10

Vidalia . . . . . . . . . . . . . . . S. A. L. Ry. . .
Vienna . . . . . . . . . . . . . . . . G. s. & F. Ry. . .

. 257 ? . 350

Wadley . . . . . . . . . . . . . . . C. of Ga. Rwy. .

. 234

GEOLOGY OF ~ 'HE OOil.STi!L PLAIN OP GEORGIA.

Pl.nl. ~'E IV._

B. A LIME 1:\'K PO:\'D IN THE CH r~'l'TAHOOCHEE FOR:UATION , ON THE PROPERTY OF i\IR . l\IIT HELL. SIX MILE WEST OF BO TON. 'J'HO)lAS COUNTY.

ELEVATIONS

Wainwright (Uptonville Station) . A. C. L. R. R.

Walden . . . . . . . .

. C. of Ga. Rwy.

Walthourville . . . . . . . . . . . . A. C. L. R. R.

Waresboro . . . . . . . . . . . . . . . A. C. L. R. R.

Warrenton . . . . . . . . . . . . Ga. R. R. . . .

Waverly . .

.IS. A. L. Ry. . .

Waycross .

. A. C. L. R. R. .

Waynesboro

. C. of Ga. Rwy.

Waynesville

. A. C. L. R. R.

Ways . . . . . . . . . . . . A. C. L. R. R.

Wellston . . . . . . . . . . . . . . G. S. & F. Ry.

Wenona . . . . . . . . .

. . G. S. & F. Ry.

.Westlake . . . . . . . .

. . . U. S. G. S. .

Wheaton, Appling County

. . . . U. S. G. S. .

Whigham . . . . .

. . . . A. C. L. R. R.

Whiteoak . . . . . Willis (Gallemore)

. . .18. A. L. Ry. . . .
. . : M. D. & s. R. R.

Weston . . . . . .

. . . S. A. L. Ry. . . .

Wilcox . . . . . .

. ...Southern Rwy. .

Willacoochee . . . . . .

. A. C. L. R. R. . .

Willingham

. A. C. L. R. R. .

Winchester . . . . . . .

. . . C: of Ga. Rwy. .

Woodbine . . . . . . . , .

. . S. A. L. Ry. . .

Worth

.. .

. . . . .G. S. & F. Ry. .

Wray . . . . . . . . . . . . . . . . A. B. & A. R. R.

57
83 . 390 . 95 . 121 . 500 . 17 . 140 . 286 . 55 . 18 . 315 . 348 235 . 201 . 265 . 19 . 394 ? . 528 . 116 . 247 . 319 463 . 20 . 415 . 392 ?

58

GEOLOGY OF THE COASTAL PLAIN

GENERAL STATEMENT OF THE GEOLOGY OF THE COASTAL
PLAIN
BY OTTO VEATCH
Georgia may be divided into three major geologic provinces: (1) . the Paleozoic area; (2) the Crystalline area; (3) the Coastal Plain. The Coastal Plain is the largest division of the three, covering approximately 35,000 square miles, considered purely as a geologic division. The general physiography, location, boundaries, topography, etc., of the different areas have been presented in the preceding chapter.
The Paleozoic region is an area of limestone, shales, and sandstones which has been subjected to great dynamic movements and the sediments are highly folded and faulted. The strata r:mgc in age from lower Cambrian to the Coal Measures. The Crystalline area, ineluding the Piedmont Plain and the Blue Ridge, is composed of rocks of igneous ormetamorphic origin, including granites, gneisses, schists, basic eruptives, and highly metamorphosed shale, sandstone, and limestone. These constitute the oldest rocks of the State, and are urobably in the main of pre-Cambrian age. They have been subjected .o great orogenic movements, have been folded, faulted, and otherwise profoundly altered. Contrasted with the rocks of the Cryst~lline area those of the Coastal Plain are sand.s, clays, and marl, with a lesser amount of limestone and sandstone; they are to a large degree unconsolidated a:Q.d have been altered but little, comparatively, from their original condition, with an entire absence of pronounced folding and faulting. The Coastal Plain sediments constitute the youngest series of beds in the State; they range in age from Cretaceous to. Pleistocene and lie upon the upturned, planated beds of the ancient crystalline complex. They are mainly marine deposits, the component materials of which were derived from the crystalline complex to the north, their bulk representing the erosion of a vertical thickness of two thousand feet or more of beds from the Crystalline area of the State. The contact between these two major divisions, the Coastal Plain and the Crystalline area, is known as the Fall Line.
Divisions of Coastal Plain Strata.-The Coastal Plain deposits underlie an immense area and aggregate a maximum thickness of 4,500 to 5,000 feet of sediments which have resulted from separate deposi-

GENERAL STATEMENT OF THE GEOLOGY

59

ticns, and which correspondingly vary lithologically and faunally.

Since to present a clear description en bloc of these sediments would

manifestly be impossible subdivisions are necessary. While the struc-

ture of the Coastal Plain sediments is simple in comparison with that
oi the Piedmont, Blue Ridge, and Appalachian Valley rocks, this

province, nevertheless, presents its peculiar difficulties and the classifi-

cations which have been arrived at in the different States represent

laborious investigations covering many years. A table of the subdi-

visions made in Georgia is given on pages 60-61.

The great geologic periods, Cretaceous, Tertiary, and Quaternary,

are based upon the life forms preserved in the rocks and great physical

or climatic changes on the earth. The broader divisions, as Lower

Cretaceous, Upper Cretaceous, Eocene, Oligocene, etc., based mainly

upon life forms preserved in the rocks, are time divisions, and are also

of wide application. The further subdivisions are provincial and

still further minor subdivisions are local and are based upon fossils,

peculiar lithologic character and stratigraphic continuity, and surface

configuration or physiography, or a combination of all of these. To

attempt to make mappable minor divisionll of the strata entirely upon

the basis of fossils or upon the basis 6f lithology alone, in either case

leads to confusion. The study of fossils is carried on because of

their value in correlating deposits of widely separated localities, the

identity of which it is not possible to prove by stratigraphic contin-

uity, or the actual tracing of a bed or formation.

.

Most of the formation and group names employed have been ab-

stracted from literature on other States, and these names are here em-

ployed, as the formations of adjoining States are continuous with

those of Georgia. Certain sections in Mississippi, Alabama, and

Florida have been taken as standards for comparison for the Georgia

formations for the reasons that stratigraphic studies were first prose-

cuted those localities.

Thickness.-The general lithologic character and thickness of the

divisions are given in the accompanying table, and will be considered

in detail in the following chapters, together with a discussion of their

structure, fossils, etc. The aggregate thickness of the deposits, as

has been mentioned, is 4,500 to 5,000 feet. Of this thickness, the Ore

taceous forms 2,000 to 2,500 feet, the combined thickness of the Ter-

tiary is approximately that of the Cretaceous, while the Pleistocene

and Recent are but little more than 100 feet. Precise measurements

of thickness can not be given, the principal reasons for which are: in-

constancy in the strata, both along the strike and dip, the merging of

strata faunally and lithologically, and paucity of fossil remains and

of natural exposures.

GEOLOGY OF THE COASTAL PLAIN

TABLE OF GEOLOGICAL FORMATIONS IN

I I SYSTEM SERIES
Recent

GROUP

THICK-

I I I FORMATION M:EMRER

NESS! FEET

Quaternary Pleistocene Columbia

Satilla formation
Okefenokee formation

J0-50 5-40

Pliocene

Miocene

Tertiary

Appalachicola Oligocene

Altamaha (Lafayette?) formation
Charlton formation
Duplin marl
Marks Head marl
Alum Bluff formati.:Jn
Chattahoochee formation
Vicksburg formation

150 ? (max.)
Undetermined
10-15
45
150 (average)
150
300

Eocene

Claiborne

Upper <Jretaceous

Jackson formation

150

Barnwell sand
Marls, Sand &c.
McBean formation Congaree clay
member
Wilcox formation

100
lC0-400 (max.)
150 (max.)

Midway formation

400

Ripley formation
.
Eutaw formation

Providence sand member Cusseta sand
member
Marine beds

950 (approx.)

Tombigbee sand member
560 Beds below T ombig-
bee sand member

Lower

Not differentiated

350-600

1. Precise measurements cannot be given; the reader is referred to the text for a discussion of the thickness of

TABLE OF GEOLOGICAL FORMATION

61

THE COASTAL PLAIN OF GEORGIA

CHARACTER
Flood plain deposits, alluvial sand, marsh mud, swamp deposits, and beach sand.
Near the coast, mud and sand containing marine shells. Fluviatile phase, coarse sand, gr~vel and clay.
Coastal terrace phase, gray sand of perhaps beach origin, and argillaceous sand andsmall amount of gravel. Fluviatile phase, coarse sand and gravel.
Widely distributed; chiefly sand, clay and gravel; beds of coarse sandstone; or grit, and local beds of greenish and drab clay and clay-stone; devoid of fossils.
Soft, white argillaceous limestone, and laminated, fossiliferous, greenish clay; the deposits are exposed only in the bluffs of St. Marys River.
Sandy shell marl, slightly phosphatic. Very sandy greenish or drab clay, fine, gray or brownish phosphatic sand and
sandy laminated clays with calcareous nodules. Marine deposits containing fossils, greenish or gray argillaceous sand and
sandy laminated clays form the greater portion of the formation. Gray and drab, compact fossiliferous limestone. Siliceous replacements at
the base of the formation contain a rich coral fauna. Mainly heavy bedded, soft, white fossiliferous limestone. The limestone is
extensively silicified, and the formation is represented at the surface by red residual sand containing flint fragments. The formation also contains sand and clay beds. Soft, heavy bedded, fc:>ssiliferous limestone and calcareous and glauconitic sandy clay. Mainly red and vari-colored fossiliferous, marine sand; thin beds of silicified limestone or chert and sandstone and quartzite.
Variable in its lithologic character; mainly an argillaceous and sandy, fossiliferous marl, and drab, sandy clays and fuller's earth.
Dark colored, lignitic and glauconitic clay in the nature of fullers earth, and vari-colored, unconsolidated sand and clay.
Ferruginous sand and local beds of white clay, together with fossiliferous limestone, marl, clay and calcareous quartzite.
Gray, calcareous, micaceous sand; dark gray to black, sandy clay and shell marl with, at intervals, nodular layers of gray, calcareous sand or impure sandy limestone of marine origin; fine to coarse, crossbedded sand. with subordinate lenses of light colored clay or dark, lignitic clay of shallow water origin.
Calcareous sand, sandy limestone, and more or less sandy clay of marine origin; crossbedded sands and clays of shallow marine or estuarine origin; at base of formation, arkosic, micaceous sand and dark gray to black clay containing lignite.
Coarse grained, crossbedded, arkosic sand with subordinate lenses of lightcolored to pure white clays, approaching kaolin in composition; contains no marine fossils and is of shallow water, and presumably of fresh water, origin.
the Tarious formations and members.

62

GEOLOGY OF THE COASTAL PLAIN

StruCture.-The Coastal Plain strata have a general southward and coastward dip with the line of outcrops of the older formations running northeast-southwest. Conclusive proof of the foregoing statements is afforded by structural data obtained from natural exposures and deep wells, together with physiographic relations. The general surface slope, independent of the dip of the geological formations, from the Fall Line to sea level is about three feet per mile. The slope of the crystalline floor at the Fall Line is 50-75 feet per mile, but whether this slope is constant as far as the present coast can only be a matter of speculation, since the full thickness of the sediments in the lower part of the Coastal Plain has never been penetrated by boring. The oldest formations form the surface rock northward and disappear southward by reason of their dip, or in other words, in traversing the Coastal Plain from the Fall Line to the Atlantic Ocean and to the Gulf one descends from the oldest to the youngest or latest deposits. The dip of the Cretaceous beds is probably as much as 40 feet per mile; the lower Eocene beds have a dip of probably 20 to 30 feet; and
the succeeding formations up to the Alum Bluff have a slope south-
ward of not more than 8 to _15 feet per mile. The Alum Bluff formation has a very low southeastward and southward dip but the beds are,
probably nearly horizontal near the Florida line. The Miocene beds
as far as known are likewise almost horizontal. The Altamaha (La-
fayette?) and Pleistocene deposits form a mantle over the older for-
mations and conform to the general tilting of the plain. The constancy of the dip of the older formations, and the con-
stancy of lithologic phases, are matters of considerable economic inter-
est, and it is regretted that more accurate information can not be given at present. The attainment of this information can be _effected
only by the further patient study of surface exposures and collection
of accurate well data. The Coastal Plain strata present no pronounced structural disturb-
ances. Some local disturbances of beds of the Cretaceous and
Eocene have been noted along the Chattahoochoo River, and displacements of beds at other localities have also been observed. None of the
observed local displacements are believed to be of magnitude and are
probably unimportant incidents in the simple oscillations which the
Coastal Plain has undergone. Broad geologic structural features which can not be proven by re-
oording strike and dip of the rock outcrops, since the dips are in gen-

GENERAL STATEMENT OF THE GEOLOGY

63

<eral so low that the strata appear horizontal, are suggested by peculiarities of the drainage. The evidence afforded by stream direction, together with geologic facts and elevations, makes the existence of certain structural features more than hypothetical.

Fig. 5.-Sketch map of the Coastal Plain of Georgia, showing relation of drainage to geologic structure.
The nature of the drainage, together with certain geologic facts, suggests that the Chattahoochee River occupies the crest of a southward pitching anticline. (See Fig. 5.) The course of the Chattahoochee is almost directly southward in contrast to the southeastward courses of the other major streams-the Altamaha, Ocmulgee, Oconee, Ogeechee, and Savannah. Flint River has a southward course more or less parallel to the Chattahoochee and is apparently located in a broad syncline complementary to the Chattahoochee anticline. A glance at the map reveals a striking inequality in the drainage divides of the two rivers. The tributaries of the Flint are much longer, notwithst:~mding that the Chattahoochee is much the larger stream. The interpretation of this is that the Flint River tributaries

64

GEOLOGY OF THE COASTAL PLAIN

have been accentuated by the slope of the eastern limb of an anticline~ whereas the Chattahoochee tributaries have developed under the adverse conditions present on the crest of an anticline. That there have been greater upward earth movements along the Chattahoochee than along the other rivers, is indicated by the much greater depth of the Chattahoochee valley, and the deep trench like channels which the main river and its tributaries have cut in the latest Pl-eistocene plain. The depth to which the river has cut into this late plain is 40 to 60 feet, while other large rivers have cut into it not more than 15 to 40 feet. The river is probably at present engaged in downward cutting since little or no flood-plain is developed along its course.
Geologic evidence of an anticline is afforded by the greater erosion and consequent exposure of the geologic formations along the Chattahoochee. The river has been able to cut into the older formations, revealing' them with greater perfection than along any other Coastal Plain stream, probably by reason of the upward earth movements which have accelerated downward cutting. For example, the intercept of the Chattahoochee water level with the Vicksburg formation is about 50 miles farther south than the intercept on the Flint. The Vicksburg, however, closely parallels the river as far north as Fort Gaines, suggesting that a great width has been completely removed by erosion. Fort Gaines would probably haYe been near the intercept had the same strike of the formations prevailed in Georgia as in Alabama, and there had been no greater uplift along the Chattahoochee than along the Flint. Local disturbances of strata have been observed along the Chattahoochee, more so than in other parts o:f the Coastal Plain, and this may be considered evidence of a general, greater earth movement in this region.
The following elevations above sea level of the higher land bordering the Chattahoochee and the Flint are significant:

Comparative elevations along Chattahoochee ana Flint Rivers.

Cusse1a Brooklyn
Richland Cuthbert Blakely

Chattahoochee Feet . 540 . 691
600
. ' . 446 . . . . 3001

Flint

Feet.

Andersonville

394

Americus

36(}

Smithville

332

Albany . . . . . . . . . . 230'

1\\'eather Bureau.

There is also physiographic and geologic evidence of a low fold or arch in the Oligocene strata, in the area drained by Ocklockonee~ Withlacoochee, and Allapaha rivers, and extending along the Florida

GENERAL STATEMENT OF THBJ GEOLOGY

65

line from Decatur to Echols counties and northward to Crisp and ~Wilcox counties (see fig. 5). The rivers mentioned flow south, whereas, normally, they would be expected to flow southeastward. The inequalities in the dr '.inage divides of these streams and the Ocmulgee and Flint are significant of an original southward slope which determined the drainage direction. The absence of tributaries on the east side of the Allapaha and the direct southeast courses of the Satilla and its tributaries and the small streams entering Okefenokee Swamp, in contrast to the almost due south course of the Allapaha, suggest that a deformation of the strata must have taken place to produce these abnormal drainage features.
The elevations also suggest an anticline since, had the usual southeast slope prevailed, the elevations on the east side of the Flint would be less than those on the west side.
Comparative elevations on west and east sides of Flint River.

West Side
Americus .. Smithville . . . . Leesburg . Dawson .... . Armena .... . Blakely ...... . Donaldsonville . . . .

Feet. . 360 . 332 . 300 ( ?) . 326 . 275 ( ?) . 300 . 139

East Side
Ashburn Sylvester Tifton .. Pelham Climax . Valdosta, .

Feet.
. 450
370
370 355 285 215

The limestone of the Chattahoochee formation appears in surface exposures in Lowndes, Brooks, Thomas, and Grady counties. This may be considered good evidence of an uplift, since, hacl the usual southeastward dip of the strata prevailed, the Chattahoochee formation would have been buried by later formations, as is the case in the eastern part of the Coastal Plain.
This broad arch or fold \vas formed some time subsequent to 'the deposition of the Alnm Bluff formation, and may have been in volved in the orogenic movement which produced the Chattahoochee anticline.
The southeastward courses of the Satilla, Altamaha, Ocmulgee, Oconee, Ohoopee, Ogeechee, Savamlah, and other streams, suggest that the eastern half of the Georgia Coastal Plain is a monocline having a general southeastward pitch. The dip and strike of the geologic formations afford conclnsive proof of the existenre of this monodine.

66

. GEOLOGY OF THE COASTAL PLAIN

CRETACEOUS
BY LLOYD WILLIAM STEPHEKSO:\
INTRODUCTORY STATEMENT
The Cretaceous deposits of Georgia form part of a connected serie:,; of formations outcropping from central Georgia through Alabama, J\lississippi, Tennessee, Kentucky, and the extreme southern part of Illinois. The area may be conveniently refened to as the eastern Gulf region.
The investigations conducted preliminary to the preparation of this report have not been confined to the State of Georgia, but have been extended along the vvhole area in which Cretaceous deposits occur in the eastern Gulf region. Nearly all tho typo sections of previouslY recognized geological formations have been studied, together with numerous additional localities. As complete sets of fossils have been collected as the semi-reconnaissance natnre of the \York permitted. ,
One of tho important results of these investigations has been the demonstration of tho fact that lithologic criteria alone can not be relied upon in establishing the stratigraphic and age relationships of the Upper Cretaceous deposits; for materials bearing a close physical resemblance may differ markedly in age and, conYersely, materials very different in physical appearance may be contemporaneous. In such cases the relative ages can only be determined by a critical comparison of the contained life remains. This has been attempted and, although additional work is needed to fill in certain gaps, it is belieYed that sufficientlY definite results have been obtained to warrant the main conelnsions' reached. The work of determining the fossils has heen hampered by the fact that the types of many of the species have not been at hand for comparison, making it necessary to depend upon descriptions and published figures. Errors have doubtless been made which will be discovered in future monographic studies of the fossils. The lists given in the texts must, therefore, be regarded as of a preliminary character.
A preliminary report on the Cretaceous deposits of the eastern Gulf rPgion hns heen prepared and will he published in the near future. The table, plate V, prepared from the data obtained through these general investigations, shmvs the lithologic variations and the age relationships of the eastern Gulf Cretaceous, and correlates these deposits with the Cretaceous of the Carolinas and the middle Atlantic region , (Yirginin, :Maryland, Delaware, and New Jersey).

CRETACEOUS

67

HISTORICAL REVIEW
The first investigator to recognize the presence of deposits of Cretaceous age in Georgia was Charles Lyell.' His conclusions were based on the results of observations made while traveling in North America in the years 1841-1842. In a statement explanatory of the general structure of the Coastal Plain of South Carolina and Georgia, he says:

"On thP whole it appears, from the information I obtained, that the less elevated part of South Carolina and Georgia, intervening between the mountains and the Atlantic, has a foundation of cretaceous rocks, containing
Hf'l<'mwites, FJ.rogyra, and other fossils, above which are, first, eocene limestones and marls, and secondly, the burrstone formation, with its red loam, mn1 th cl clays, and yellow sand."

Beds of J,o\YCI' Cretaceous age near Augusta \\'ere examineJ by him, but he did not distinguish between them and merlying- Eocene strata.
Dnring a second visit to ~orth America in the years 1845-1846 Lye1l' visited parts of Georgia in which strata of Cretaceous age appear at the surface. The Cretaceous beds in the vicinity of Macon, Bibb County, \Yere referred to the Tertiary, no distinction being made between them and the overlying fossiliferous beds of the Eoclne. The Cretaceous age of some of the strata near Columbus was rPrognir.ed. The fo1lowing is quoted: (p. 33.) '

"Columlms, lil'e so many towns on the liorders pf the granitic and ter-
tiary re~ions. is situated at the head of the navigation of a large river, and the rapids of the Chattahoochee are well seen from the bridge by which it is here spanned. The vertical rise and fall of this river, which divides Georgia
fron-o Alabama, amounts to no less than 60 or 70 feet in the course of a year; and the geologist should visit the country in November, when the season is healthy, and the river low, for then he may see exposed to view, not only thP horizontal tertiary strata, but the subjacent cretaceous f!eposits, containing ammonites, baculites, and other characteristic fossils. These organic remains are met with some miles below the town, at a point called 'Snake's Shoals;' and Dr. Boykin showed us a collection of the fossils at his agree-
"ble villa in the suburbs. In an excursion which I made with Mr. Pond to the Upotoy Creek, I ascertained that the cretaceous beds are overlaid everywhere b~ tertiary strata, containing fossil wood and marine shells."

In 1849 George -White' gave a brief account of thf' geology of Georgia. Of the Cretaceous he says: (p. 21.)

"The Cretaceous formation is, with the exception of a small patch at Sandersville confined to parts of the counties of Randolph, Stewart, Mus-
1Quarterlv .Tournai, Geol. Soc. London, Vol. 1. 1845. pp. 429-442. 2A Second Visit' to the United States of North America, London, 1849, 2 Vols.; 1st vol., 368 pp. ; 2d vol.. 385 pp. Especially 2d vol., p. 33. Statistics of the State of Georgia; Savannah, 1849 620 pp. Geological map of State at end. Especially pp. ~1, 448, 495, 522.

68

GEOLOGY OF THE COASTAL PLAIN

eogee, Marion and Macon. Although its existence in these counties is well es-
tablished by characteristic fossils, but little is known of the nature .of the
roclu; in which they are found. A deposit in the Chattahoochie in Stewart County, from which the writer of this article, through the liberal exertions
of H. T Hall, Esq., of Columbus, and I. C. Plant, Esq., of Macon, obtained teeth of the Geosaurus, Mosasaurus of an extinct crocodile, Lamna accuminata, and Galleus pristodatus, is identified with the ferruginous sand formation of New Jersey, as well as by the constitution of the soil as by its fossil remains.
"On the Petalau Creek in Randolph County (now Clay County), and at ~everal other points, Ammonites placenta, Exogyra costata, Belemnites Americanus, and a large Cucullia have been found."

On a geological map of the State at the end of the Yolmne, the Cretaceous is represented as covering a triangular area east of Chattahoochee River, cornering at Columbus, KnoxYil1e, and the month of Pataula Creek on Chattahoochee River.
In 1853 Jules :Marcou' published a geological map of the United States, in which the Cretaceous is represented as cmering a triangular area in Georgia similar to that represented on the map of George White, but J\Iacon is made the eastern corner of the triangular area instead of Knoxville.
In 1858, H. D. Rogers,' describing the distribution of Cretaceous deposits in the United States, Rai<l COJH'erning- their occnrrencc in the Eastern Gulf region: (p. 765.)

"The great continuous southern belt commences in Georgia near the Oconee River south of Milledgeville, and quickly expanding to a width of 60 or SO miles, extends W. from the Flint River of that State through Alabama, where it sweeps around the S. promontory of the Appalachian chain and the Paleozoic formations, and stretches northward, holding about the same
breadth, through Mississippi and western Tennessee as far as the W. corner
of Kentucky.''

An important contribution to the Paleontology of the Cretaceous of the Chattahoochee _region made by T. A. Conrad' in 1860. He describes a large number of new species of invertebrate fossils from Eufaula, Barbour County, Alabama, collected by J\1. Tuomey, State Geologist. He correlates the horizon from which they were taken with Cretaceous beds at Owl Creek, Tippah County, Miss., from which he had recently described 56 new species of invertebrates.
The general distribution and character of the Cretaceous deposits

lA Geologlclil Map of the United States and the British Provinces of North

America ; with an explanatory text, 92 pp., and eight plates of characteristic fossils.

Boston, 1853.

'Sketch of the Geology of the United States, Geology of Pennsylvania, Vol. 2, 1858,

of pp. 741-778. Descriptions of New Species of Cretaceous and Eocene Fossils

Mississippi and

Alabama. Jour. Acad. Nat. Sci., Phila., n. s. Yol. 4, 1858-1860. pp. 275-298, pls. 46-47.

'Conrad observations on a group of Cretaceous fossil shells. found in Tippah County.

~Ii""issippi. with descriptions of fifty-six nrw species. .Jour. Acad. Nat. Sci.. Phila.,

n. s., vol. :l. 1 f!i\5-1858, pp. 323-336, pls. 34 and 35.

CRETACEOUS

69

of the State were described by Dr. George Little, State Geologist of Georgia,' in 1876. He says: (pp. 38-39.)
"In the Mesozoic age, or Secondary of the old geologists, the Triassic and Jurassic periods-represented in other Atlantic States by sandstones, coal and trap dikes-show only the trap dikes of Meriwether, Habersham, and other counties, the sandstones, if they exist, being buried under the deposits of sand, clay, and sandy marls filled with the shells of various animals which lived in the Cretaceous age in the sea-water which washed against the hard granitic cliffs forming the shore line from Columbus to Butler. The greatest quantity of these remains is found on the. banks of Pataula Creek, in Clay County. On examination, these shells prove to be unlike those of animals now living, and also different from those which are found in Northwest Georgia, in the rocks made in Paleozoic time; and hence, as they are intermediate, the age is called that of Middle Life, from the Greek word mesos (middle) and zoe (life). The forms correspond to those found in the Chalk Cliffs of England; and hence they belong to the Cretaceous age, from the Latin word creta (chalk).
"After the sea-bottom of the Cretaceous period was raised above the level of the water, the shore-line extended from Pataula Creek, by Butler, Macon, and Milledgeville, to the Savannah River at Augusta."
The Cretaceous deposits of central and western Alabama were deseribed and classified by Prof. Eugene A. Smith and Mr. L. 0. Johnson' in 1887. Four divisions of the Cretaceous were recognized, in ascending order, as follo-ws: Tuscaloosa formation, referred questionably to the Cretaceous; Eutaw formation; Rotten limestone; and Ripley formation. The terms Tuscaloosa and Eutaw were used in essentially the same sense as understood by the present writer. The term "Rotten limestone" is synonymous with Selma chalk, later adopted for the same terrane. The Ripley formation appears to have included a portion of the upper part of the "Rotten limestone," and certainly sands and clays above the "Rotten limestone," since shown to be of Eocene age. The occurrence of Cretaceous deposits in eastern Alabama is not discussed in the text, but their supposed distribution in that region is indicated on a map accompanying the report. Two of the divisions, the Eutaw and Ripley formations, are represented on this map as extending eastward and intersecting the Chattahoochee River. The former apparently coincides approximately with the Lower Cretaceous terrane of the present report, and the latter ineludes all the Upper Cretaceous strata exposed on the river, embracing the Euta" and Ripley formations of the present report.
The presence of Cretaceous strata along the fall line extending entirely across the State of Georgia, from Augusta to Columbus, was first recognized by J. \V. Spencer.' He describes a formation resting
1Hand-book of the State of Georgia, accompanied by a Geological Map of the State. Atlanta. 1876. 256 pp.
'Tertiary and Cretaceous strata of the Tuscaloosa. Tombigbee, and Alabama rivers : U. S. Geol. Surv. Bull. No. 43, 1887, 189 pp., 21 pls., especially pp. 71-138.
'"Southern drift" and its agricultural relations: Bull. Exp. Station. Georgia, 1890. 5 pp.

70

GEOLOGY OF THE COASTAL PLAIN

upon the surface of decayed crystalline rocks in the fall line region, consisting of sands, clays, and graYels. The terrane is said to be generally covered with newer deposits, but is exposed along streams and
in road- and railway cuttings. He correlates these deposits with the Tuscaloosa formation of Alabama, and with'the Potomac group of the Middle Atlantic region. The terrane corresponds to the LmYer Cretaceous terrane of the present report. The same year \Y J ::\IcGee described briefly the character and relations of the Putomac formation (corresponding to the Lower Cretaceous of this report) in the
vicinity of 1\facon, Bibb County, and Columbus, JI.Iuscogee Connty, Ga.'
The first detailed account of the Cretaceous deposits exposed on Chattahoochee Ri,er was furnished by D. W. Langdon.' ~\.. general
eection along the river from Columbus, Ga., to Alum Bluff, Fla., is given. Cretaceous strata appear in the river bluffs from Columbus
to a point abont eight miles ahon' Fort Gaines, Ga. Tlll'f'e cliYisiom are distinguished. The lowest of these, the "Tuscaloosa gronp," cm-
responds to the Lower Cretaceous of this report. Langdon mistook these Lower Cretaceous sands and clays for the eastward extension of
the Tuscaloosa formation of Smith. The second division recognized, the Eutaw group, corresponds to tl1c E11taw formation of thi,- report,
minus the Tombigbee sand member. The third division recognized, the Ripley group, included the Toll,lbigbee sand member of the Eutaw formation and the Ripley formation of the present report.
Commenting on the absence of the Rotten limestone (Selma ('halk) in the Chattahoo('hee region, Langdon says: (p. 591.)
"East of the drainage of the Alabama River the Rotten limestone, such as occurs in :VIarengo, Perry, Dallas, Lowndes, and Montgomery counties, (Alabama), is not represented. The exact eastern limit of this group has not as yet been determined, but evidences of its decreasing thickness are seen in the narrow outcrop in the neighborhood of Pike road, Montgomery county, where its north and south extent is only five miles, as compared with thirty miles in Dallas County. Further than this decrease in thickness, present information does not warrant saying anything. As has been stated before, no rocks bearing any lithological resemblance to the Rotten limestone have been seen overlying the Eutaw group on the Chattahoochee River. Whether or not this group is represented by strata of different composition from the typical aluminous limestone it is difficult to say, since no critical examination of the fossils of the several divisions of the Cretaceous has yet been undertaken. It is much to be regretted that the divisions have been made on such arbitrary grounds as mere lithological differences, since marked variations can be noted in almost any stratum of any of the groups, and experience in both the Tertiary and the Creta.ceous of Alabama has proved the risk of creating groups on any but combined physical and faunal differences."
'Southern extenRion of the Appomattox formation: Amer. Jour. Sci., :'ld ser.. vol. 40. 1 RllO. pp. H5-4l. especially pp, 22, 23 ..
'Variation" in the Cretaceous and Tert1ary strata of Alabama: Rnll. G0ol. ~or. America, vol. 2. l 890, pp. i'i87-606.

CRE1'ACEOD8

71

In 1891 J. \Y. Spencer' gave a brief account of the Cretaceous deposits in Georgia between the Chattahoochee and Flint riYers. He adopts Langdon's classification of the Cretaceous, and repeats his section along Chattahoochee River, (pp. 91-99). In a sketch map of the region between Chattahoochee and Flint rivers, the {Jretaceou8 is represented as forming a belt intersecting the former river from Columbus to a point eight miles above Fort Gaines, and intersecting the latter river from Knoxville to :Montezuma. The "Tuscaloosa formation," corresponding to the Lower Cretaceous beds of this report, is represented as forming a belt about eight miles wide along the northern edge of the Cretaceous area.
An admirable detailed report on the geology of the Alabama Coastal Plain, by Prof. Eugene A. Smith an,d J\iessrs. L. C. Johnson and D. W. Langdon/ appeared in 1894. No changes are made in the main divisions previously recognized, as announced by the same authors, in publications already cited. The Cretaceous age of the Tuscaloosa formation, previously referred questionably to the Cretaceous, is definitely assigned to that period. On the authority of Prof. \Vm. J\L Fontaine and Lester F. Ward, who studied the plant remains, the formation is correlated with the "Amboy clays" (Raritan formation) of the Middle Atlantic States, and with the Dakota ''group" of the Western Interior. The name Selma chalk is proposed as a co-name with the term "Rotten limestone."
George E. Ladd' in 1898 published a preliminary report on the clays of Georgia. The fact, previously made known by Spencer, that a Potomac group equivalent is present in the fall line region, entirely aeross the State from Augusta to Columbus, is more clearly demonetrated. He describes in detail many of the exposures in the fall line region between the cities mentioned. The terrane described includes the strata referrerl to the J,mYer Cretaceous in this repurt.
In 1903, Prof. S. \V. ~[cCallie' described an interesting occur-
rence of sandstone dikes in the Cretaceous clays at Slick B1nff, Chat-
tahoochee River. (Sre page 120 of this report.) Ire expresses the
opinion that the dikes originated as sand fillings in fis~ures produced
by earthquakes. The clays and kaolins of the Cretaceous deposits of the State ~were
1Geol. "Surv. of Georgia. First report of progress, 1800-91, 128 pp. Especially pp. 26-40, and Hl-fln.
2Report on the Geology of the Coastal Plain of Alabama: Geol. Surv. of Ala., :Montgomery. 1804. 75!) pp., 29 plates. especially pp. 255. 372, 422. 44ti.
3A Preliminary Report on a Part of the Clays of Georgia; Geol. Surv. of Georgia, Bull. No. 6-A, 204 pp., 17 plates, especially pp. 85-165.
See also Notes on the Cretaceous and Associated Clays of Middle Georgia. Am. Geol., Vol. 23, 1899, pp. 240-249.
sandstone Dikes near Columbus, Georgia. Amer. Geol.. Yo!. 33, 1D03. pp. 19!}-202.

72

GEOLOGY OP THE COASTAL PLAIN

briefly described by Otto Ycatch' in 1907. Their general distribution 2nd character are indicated and a number of specific localities are described.

In 1908, Prof. S. W. McCallie' published a report on the underground waters of Georgia, in which a brief account of the geology of the State is given. He adopts Langdon's classification of the Cretaceous. The entire Cretaceous is represented by one color on the geologic map.

The discovery of bauxite in Georgia in beds of Lower Cretaceous age was announced by Otto Veatch' in 1908. The deposit is located iu -Wilkinson County, near Mcintyre. The ore occurs at the top of the Lower Cretaceous, and in the opinion of the author is an alteration product of the white clay or kaolin which is common in this terrane in -Wilkinson County.

In 1908 Otto Veatch gave a brief account of the remarkable white clays, or kaolins, occurring in the Lower Cretaceous, principally in Twiggs County. He discusses their geological occurrence, structure, and origin.

The Georgia Survey in 1909 issued a report on the clays of thP

State, by Otto Veatch.' A more complete account of the Cretaceous of

the State than that contained in Professor :Mc0flllie's water resources

report is giwn. Veatch recognizes the same main divisions of the

Cretaceous as appear in Langdon's classification. The Ripley, how-

ever, he s11bdivides into four parts, namely, in ascending order, the

"BlufftmYn marl," the Cusseta sand, the "Renfroe<; marl," and the

Providence sand. A black and white map is given opposite page 88

of his report showing the distribution of the several Cretaceous divis-

ions. His usage of names for Ripley subdivisions as compared with

that adopted for the present report, is explained as follows: The

"Blufftown marl" corresponds to the Tombigbee sand member of the

Eutaw formation and to a part of the overlying Ripley formation;

the Cusseta sand is the Cusseta sand member of the Ripley forma-

tion; the "Renfroes marl" is composed of characteristic Ripley mate-

rials and requires no special membership designation; and the Provi-

dence sand becomes the Providence sand member of the Ripley form-

ation.

'

Detailed accounts are given of the Cretaceous clays of economic

'Kaolins and Fire Clays of Central Georgia: U. S. G. S. Bull. No. 315, 1907, pp. :101-314.
'Underground Waters of Georgia: Geol. Surv. of Georgia, Bull. No. 15, 370 pp., 29 plates. especially pp. 35-36, geological map opp. p. 32.
3A new discovery of bauxite in Georgia: Eng. & Min. Jour., vol. 85, 1908, p. 8& 4The kaolins of the Dry Branch region : Econ. Geol., vol. 3, 1908, pp. 109-117. 'Second report on the clays of Georgia : Geol. Survey of Ga., Bull. No. 18, 1909, 453 pp.. 32 plates, especially pp. 82-106.

GEOLOGICAL SURVEY OF GEORGIA

Northern Miui56 ippi

Weetern Alabama

Central Alabama

1
Abtle nt

Absent

a. The !tnatigraphic position of the bue of the Bh"~k Creek formation with reference to the eastern Gulf section has not been established with aeeuracy b Correlated with the Patuxent fottn:1tion on physkal evidencP on ly c The synchron~ity ol the Lower Cretaceous struta of the eastern Gulf region with the Pat1.u::ent. fom1ation has not been established
Note: Within the Crt!taceolll' portions of the columns age eq uivalencKs nre shown by horiront:ll linea, or may be determined by project ing horizontal lines
The spacing in the table does not ind icate relative thicknesses of fonnati on&
Oblique dashed lines indicate the t hinning or disappcaranC'e of fonnations or memben either by the mergence of the beds along the strike into other types of material , or by ~e vinching out of the beds by unconfonnity

PLATE V

Eastern Alabftma Eocene

Chattahoochee Ri\8'"

Western Georgia eut of immediate C1111.ttl\hoochoo region

CA!ntrnl Georgia

EAstern Georgia

South Carolinn. Eocene

North Carolina Eocene

North Atl:mtic (:\l uryla nd, ~lawnn?-,
and New Jersey)
Eocene

.......... '

Mttn.asqU:\rt

Rancocas

-----

Ahsent
I

' '
\
' ''' \ ' ' '
\ \ \

Peedee forma tion

Bln<k
c...k
fornw.:tion

Mkldendorl .................

arkose member of .........

_,.1Black Cl'l'C~ formation ....... ....

_j

... ... .......

formation

!o.lonmouth

Blaek

Mat.awan

c....k

---------- _,_

formation

a ?--?......,,-,------ -

?

Magothy

' '

Aboenl

' '

Aboent
I

Absent

Absent

' ' '',, ftaritan
---~--~
., ,..............

,.,.. ......

~~~~r-------~~r-~-.--------.-----~~---------~~~~------------r~~~~-- ------.------~------- fr-----~~------------- {I-A-run-d-el ~

b

Lower c

Pw.tuxent

Patux~nt

Cret.nceoWI
Crystallines

forma tion

fonn:ttion

7c~C-ry-st-al-lin-e+s ------------

c ? !-1C_r_y>_ta_l_lin-.,-1

LWpiltha protuta sub-wne
Upper limit ol range of typb.l U:vgrra potldt1'0114 and lower limit of range of t yp' :tl EXOf/1/T'G CD~~ta.la.
I 1---i Mrt.,.iaon>uub-zone

Tomhigbee mod member

Ripley formati n Eutaw fonnation

LEG EN D

sm~":~~:: {~

S.lma chalk Cusoetn {

Ripley fonnation ~

blind member

c5

~

:>

R

Tusc.alocma formation
lLower Crelaeeoc

TABLE SHOWI.J."\fG THE LJTHOLOGIO VARIATIONS OF THE EA TERN GULF CRETACEOUS DEPOSITS, Ali'D THE AGE RELATIONSHIPS OF THE CRETACEOUS DEPOSITS OF GEORGIA TO THOSE OF THE REMAINDER OF THE EASTERN GULF REGION; ALSO THE CORRELATION OF THE EA TERN GULF CRETACEOUS WITH THE CAROLINA .AND NORTH .ATLANTIC CRETACEOUS.

LOWER CRETACEOUS

73

value, and Appendix D, pp. 430-447, is devoted to the bauxite deposits of the Lower Cretaceous beds.
Lists of species from the known Cretaceous fossil plant localities of
Georgia were recorded by E. vV. Berry' in 1910, and in the same
paper a new genus and species of Euphorbiaceffi from one of the localities, McBride Ford, is described.

LOWER CRETACEOUS

DEFINITION
Areal distribution.-The Lower Cretaceous strata present in Georgia constitute a terrane 'whose exact correlation with reference to Lower Cretaceous deposits to the northward in the Atlantic Coastal Plain is at present not definitely known, but they are believed to represent a part of the Potomac group of the Middle Atlantic States. This terrane appears in surface outcrops in Georgia in an extremely irregular belt 2 to 30 miles in width, extending entirely across the State from Chattahoochee River in the vicinity of Columbus, northeastward to Savannah River in the vicinity of Augusta. The irregularities of the belt are due partly to the unevenness of the surface of the basement rocks upon which the formation rests; partly to overlaps of younger formations; and partly to the deep erosion valleys that the streams have developed along the fall line region, causing the underlying basement rocks to appear much farther southward in the bottoms of these valleys than would otherwise be the case, and likewise causing the Lower Cretaceous beds themselves to appear . still farther down these valleys beneath the overlying younger formations. These irregu~arities are most strikingly developed in the region between Ocmulgee and Savannah rivers. (See geologic map, opposite page 58.) The area in which the beds appear includes parts of the following counties: Muscogee, Chattahoochee, Talbot, Marion, Taylor, Macon, Crawford, Bibb, Twiggs, Jones, Wilkinson, Baldwin, Washington, Hancock, Warren, Glascock, J efferson, McDuffie, Columbia, and Richmond.
This Lower Cretaceous terrane continues westward from Georgia into Alabama, forming a belt four to eight miles wide lying just south of the Piedmont border, and extending to and probably somewhat beyond the Alabama River.
Stmtigraphic position.-The Lower Cretaceous beds in Georgia rest upon a basement of ancient crystalline rocks, all of which are believed to be of pre-Cambrian age. The unconformity separating
1Contributions to the :\Iesozoic flora of the Atlantic Coastal Plain, VI Georgia: Bull. Torrey Botan. Club, Xo. 37, 1910, pp. 503-511.

74

GEOLOGY OF THE COASTAL PLAIN

the bailement rocks from the Lower Cretaceous deposits represents an

enormous time interval, including all of Paleozoic time, and the

Triassic and Jurassic periods of :Mesozoic time. The surface of the

crystalline rocks is very uneven in detail, but in general, slopes to tl~~ south and southeast beneath the Lower Cretaceous beds. Calcula-

tions from well borings at several places have shown that the amount

of this general slope in the region of the fall line nries from 25 to

over 50 feet to the mile. In Jefferson County it maintains a slope of

between 35 and 40 feet to the mile for a distance of nearlv 40 miles

away from the Piedmont border.

"

Between Chattahoochee and Ocmnlgee rivers the formation is over-

lain unconformably by Upper Cretaceous strata belonging to the

Eutaw and Ripley formations, and to a very limited extent, when

both of these formations are absent, by Eocene strata; between

Ocmulgee and Savannah rivers it is merlain unconformably by

Eocene strata of the Claiborne group. Locally, where the formation

is crossed by the larger streams, it is overlain along the valley sides

by thin Pleistocene terrace deposits.

The unconformity separating the Lower Cretaceous deposits from

the overlying Eutaw formation has been observed at a number of

places in Muscogee and Chattahoochee counties, Ga. (see detailed

sections) ; but the locality \vhere it is best exposed and least obscured

by weathering, as thus far observed, is in Russell County, Ala., four

miles southwest of Columbus, Ga. The contact at this point is sharp

aud unmistakable. Its rharacter is well shown in the photograph,

plate VI, B. The contact has also been observed on Alabama River,

tive miles above Montgomery.

A short distance west of Alabama River in Alabama tho formation

pinches out entirely between the basement rocks and the overlying

Tuscaloosa formation, allowing tho latter to rest directly upon the

basement floor.

Lithologic characters.-The Lo\Yer Cretaceous materials consi~t predominately of arkosic sand, with, however, a considerable percentage of clay in the form of interbedded lenses. The sands are usnal1.v coarse to very coarse in texture, and cross-bedding is general. They are composed largely of angular to subangular quartz grains, \vith, howcser, an important percentage of kaolin grains and disseminated kaolin particles. In addition, there are subordinate amounts of unrlecomposed felclspar, mica, and varjous other minerals derived from the crystalline rocks of the adjacent Piedmont region. Locally, the sand becls haw been indurated, forming friable sandstones. The cla; lenses vary \Yidely in lithologic character, shape, and extent. In thickness they range from an inch or less to a maximum of 30 or 40

LOWER CRETACEOUS

75

feet, and in horizontal extent from a few square feet to many acre~.

ln general, the clays are light drab or gray in color, and are more or

less sandy. Locally, howeve:r;, there are commercially important clay

lenses of remarkaLlc 11hiteness awl purity approaching kaolin in com-

!J08ition. Lamination is rare, the beds being as a rule massiye and

breaking with a hackly or conchoidal fracture.

_

For the most part the formation displays great irregularity of bed-

ding. In places, however, a distinct banding of the c_lay and sand

layers is apparent, indiYidual beds being traceable for considerable

distances. Good examples of the latter type of bedding are presented

by the bluffs of Chattahoochee River below Columbus.

Locally, coarse gravel lenses and layers occur in the formation, this

being especially true of the basal portions near the contact with the

underlying crystalline rocks. Unconformities of little or no time

significance occur locally within the formation. ~ls the result of the

shifting of the channels which produced these unconformities clay

beds within the formation have been torn to pieces and redeposited,

as evidenced by the large number of rolled clay ball,; and Lonlders

which in many places occur scattered through the sands. The better

grades of commercially important clays, so far as known, occur in

the region between Ocmulgee and Savannah rivers. Beds of very

fine quality are abundantly developed in Twiggs County and hero

mining operations have been carried on more extensively than else-

where. The same formation contains similar high grade ,,.hite clay

beds to the northward in Aiken County, S. C.

In Wilkinson County the white clays ha1e been locally altered to

bauxite with pisolitic structure. The bauxite deposits, so far as

- known, occur immediately beneath the contact of the formation with

overlying Eocene strata. The white clay and bauxite deposits have

been described in considerable detail by Otto Veatch.'

Strike, dip, and thiclcness.-Thc strike of the Lower Cretaceous beds in Georgia is in general a little south of a northeast-southwest direction. In Alabama the strike is almost clue east and west. There is a slight general dip of the beds to the southeast or south at right angles to the line of strike. On account of irregularity of bedding, and also on account of the limited extent of the exposures, the exact amount of dip can not be readily cleterminecl. It is greater, however, than the gradients of the larger streams aml probably averages 25 or 30 feet to the mile. Data are available for a fairly accurate cletnmination of the thickness of the formation in the Chattahoochee Valley below Columbus. The point on Chattahoochee RiYcr adjacent to

1GPoL Survey of Georgia, BulL ~o. 1><.

76

GEOLOGY OF THE COASTAL PLAIN

Uolumb11s, \Yhere the surface of the basement rocks passes beneath zero water level, has an elevation of about 195 feet above sea level. Data furnished by well borings near the mouth of Bull Creek shmv that this surface dips southward beneath the Lower Cretaceous beds at an average rate of between 50 and 60 feet per mile. The top of the Lower Cretaceous terrane passes beneath water level at Broken Arrow Bend, an air-line distance of seven miles south of Columbus, at an elevation of about 180 feet above sea level. If the dip of the surface of the basement rocks is 50 feet to the mile, seven miles south of Columbus at Broken Arrow Bend, it would be 350 feet lower, or 155 feet below sea level. The thickness of the formation at this point
+ would therefore be 155 feet 180 feet, or 335 feet. If the dip of
the basement rock surface is 60 feet to the mile instead of 50 feet the same method of calculation would give the thickness at 405 feet. Three hundred and seventy feet, the average of these amounts, is be1.ieved to be a close approximation to the total thickness at this point.
Calculations based upon well data have shown that the probable general dip of the unconformity separating the Lo\ver Cretaceous and overlying Eutaw beds in this region is 48 or 50 feet to the mile. This slope is therefore probably a little less than the slope of the surface of the underlying basement rocks. If these two plains maintain their respective degrees of dip they must diverge slightly and the formation must thicken somewhat to the southward. It seems improbable, however, that the buried surface of the basement rocks maintains so great a degree of slope southward for any great distance away from the fall line as it is known to possess in close proximity to the fall line.
A well at Reynolds, Taylor County, is said to have penetrated 600 feet of Cretaceous strata before encountering the underlying crystalline rocks. As the well starts in Lower Cretaceous strata this whole thickness, 600 feet if correctly reported, should be referred to this for-
mation.
Three and one-half miles southwest of Louisville, in Jefferson County, a well 1,143 feet deep is believed to have penetrated about 790 feet of Cretaceous strata between the overlying Eocene deposits and the basrment roch. X one but Lower Cretaceous strata outcrop at the surface from beneath the Eocene beds along the fall line to the northwest of Louisville, hut it is not at all certain that all of the Cretaceous beds penetrated in the Louisville well should be referred to that division. In fact it seems highly probable that buried Upper Cretaceous strata exist between the Eocene and Lower Cretaceous beds. The thickness of the Lower Cretaceous terrane at this point is therefore believed to he ronsiderahly less than 7fl0 feet.

LOWER CRETACEOUS

77

From data obtained from wells, and from other considerations, it may be shown that in general along the line where the formation passes beneath the overlying Upper Cretaceous or Eocene formations, as the case may be, its thickness ranges from 350 to 600 feet, although the amount may be less or greater locally.

Physiographic expression.-The belt in which this Lower Cretaceous terrane outcrops at the surface constitutes part of a dissected plain which is characterized by a broken, hilly topography, the area presenting in fact the roughest surface of any portion of the Coastal Plain of Georgia. The elevation of the upland surface ranges from 400 to 600 feet above sea level. The major streams crossing the area have elevations at the fall line at zero water level, ranging from about 100 feet to about 250 feet. The surface relief therefore reaches a maximum of at least 400 feet. This hilly topography is the result of active stream erosion caused by the relatively high elevation of the area and favored by the unconsolidated, sandy character of the materials of which the formation is predominantly composed.
The surface soil throughout the greater part of the area is composed of loose gray or yellowish sands, the product of the weathering and leaching of the underlying sand beds of the formation. TheRe surface sands have been shifted more or less by winds and torrents so that in places they have been entirely removed, and elsewhere have been heaped up to abnormal thicknesses. The area forms a part of the socalled "sand hill" region of the northern part of the Georgia Coastal Plain.
Paleontologic characters.-A few, faint, indeterminable leaf impressions have been observed in white, sandy clay in a cut of the Georgia Railroad at Carr's Station, Hancock County. \Yith this exception no fossil remains haYe been discovered in the beds of this formation in Georgia.
A few poorly-preserved leaf remains were recently collected by the
writer from this terrane at an exposure in a bluff of Tallapoosa
River at Old Fort Decatur, Macon County, Alabama. These were
submitted to E. W. Berry, who expresses the opinion that the beds
containing them are of Lower Cretaceous age, and they are believed to represent a part of the Potomac gro1~p of the Middle Atlantic
States. Further reference will be made. to these in the section on
correlation, pp. 108-111. The cast of a Urzio, specifically indeter-
minable, was fo.nnd in close association with thf' plant rf'mains at this
locality.

GEOLOGY OF THE COASTAL PLAIX

DETAILED SECTIONS
Chattahoochee River.-Lower Cretaceous strata are exposed in the bluffs of Chattahoochee Ri,,er from Columbus, ~Iuscogee County, to Broken Arrow Bend, Chattahoochee County. The specific localitie~ referred to on the following pages are indicated in a sketch map of the riYer, Figure 6.
At Columbus the Lower Cretaceous beds rest unconformably upon a basement of ancient crystalline rocks. The latter form the body of the hills north of the city and giYe rise to the rapids in the river opposite the northern half of the city. Their surface dips rapidly to the southward under the Coastal Plain sediments, passing beneath "'ater level a short distance below the Central of Georgia RaihYa~' bridge. The following section shmYs tl1e relation of the T~mwr Crrtaceous strata to the underlying basement rocks and to the oYrrlying Pleistocene terrace deposits.

Section, Chattahoochee River, bluff at Gira1d, opposite Columlms, nf II'Psf e11d of Cr11fml of Georgia Railuay bridge.

Feet. In.

Pleistocene (terrace deposit)

7. Red, coarsely arenaceous clay . . . . . . . . . . . . 6

G. Reddish 'and yellowish, argillaceous sand and sandy

clay, coarse and pebbly, with pockets of pebbles,

becoming much coarser along base. . . . . . . . 14

5. Dark, tough, plastic, sandy clay with indeterminable

plant fragments . . . . . . . . . . . . . . . . . . 11

4. Coarse, irregularly bedded sand and gravel, the
pebbles averaging 1/ to v~ inch in diameter and

angular to partially rounded . . . . . . . . . .

G

(Unconformity)

Lower Cretaceous

3. Light drab, massive, coarsely sandy, compact clay . 9

2. Argillaceous, very arkosic, light gray, friable sanct

stone . . . . . . . . . . . . . . . . . .

3

(Unconformity)

Basement rocks 1. D\'eply decayed crystalline rock (gneiss) to low

water level . . . . . . . . . .

5

On the south edge of the town of Girard, west of the Central of Georgia Railway track, there is an excellent exposure of I~mYer Cretaceous strata in a sand pit. The succession of .beds as they appeared
when visited, is as follows:

Section at south ern outskirts of Gimrd, Ala.
Feet
Pleistocene? (or surface creep) . 6. Sandy and pebbly loam . . . . . . . . . . . . . . . 2 (Unconformity)
Lower Cretaceous

LOWER CRETACEOUS

79

N

35

Alexanders Ldg. Othosldg.

Fort Gaines

Scale

0

5

10

IS MILES

Fig. 6.-Sketch map of Chattahoochee, River, Columbus, Ga., to Fort Gaines, Ga.

80

GEOLOGY OF THE COASTAL PLAIY

5. Reddish sandy loam, grading down into harsh,

sandy clay, and this in turn into a slightly in-

durated, arkosrc, micaceous sand . . . . . .

. 25

4. Mottled purplish and gray, harsh clay . . . . . . . . 3

3. Hard, grayish to somewhat mottled, sandy clay . . . . 6

2. Gray, in places iron-stained, loose, cross-bedded, very

arkosic and micaceous sand becoming very coarse

and gravelly in lower six feet

. 16

1. Light, greenish drab clay . . . . . . . . . . . . . . 12

The base of the preceding section is ao or i35 feet above zero \Yater
level in the river. The first prominent exposure immediately on the river below Co-
lumbus is at a point about one-half mile above the mouth of Bull Creek on the Georgia side. The section in detail is as follows:

Section one-half mile above the mouth of B1tll Creek, Chattahoochee River, left bank.

Pleistocene (terrace deposit)

Feet

4. Yellowish sandy loam grading down into coarse simd and gravel . . . . . . . . . . . . . . . . . . . . 33 (Unconformity)
Lower Cretaceous

3. Light gray to white, very coarse, cross-bedded, ar-
kosic sand, containing pebbles up to 14 inch in
diameter . . . . . . . . . . . . . . . . . . . . . 13

2. Harsh, greenish gray clay, mottled with brown . . . 2 6

1. Greenish gray, finely micaceous, argillaceous sand, to water's edge . . . . . . . . . . . . . . . . . . 3

The cross-bedded, arkosic layer in the preceding section undulates along the bluff but in general dips gently southward and comes to water level a few hundred feet below where the section was made.
A section similar to the preceding occurs at the mouth of Bull Creek.
Thirty-nine wells have been recently drilled in Muscogee County about three miles southeast of Columbus, on either side of Bull Creek and within one mile of its mouth. All passed entirely through the Lower Cretaceous beds and entered the underlying basement rocks. Logs of two of these wells are given below. Mr. N. W. Wood, Constructing Engineer of the Hudson Engineering Company, 90 ~West Street, New York City, N. Y., is authority for the lithology.

GEOLOGY OF THE COASTAL PLAIN OF GEORGIA.

PLATE VI.

A. CLAY PIT AT PLANT OF THE GEORGIA KAOLIN COMPANY, TWO MILES SOUTHEAST OF DRY BRANCH, IN TWIGGS COUNTY, GA., SHOWING CONTACT BETWEEN WHITE KAOLIN BED OF THE LOWER CRETACEOUS AND OVERLYING SANDS AND CLAYS OF THE CLAIBORNE GROUP (EOCENE).
B. EXPOSURE IN CUT OF COLUMBUS-SEALE ROAD, FOUR MILES SOUTHWES'l' OF COLUMBUS, GA., IN RUSSELL COUNTY, ALA.. SHOWING CO:::-<TACT BETWEEN LOWER CRETACEOUS BED AND THE OVERLYING EUTAW FORMATION.

LOWER CRETACEOUS

81

Log of Well No. 11, located about 600 feet southeast of the mouth of Bull Creek.

Lower Cretaceous (except a few feet of undifferentiated Pleistocene terrace

material at top)

Feat

16. Clay

. o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 to 56

150 Soft sand rock 0 0 0 0 0 0 0

56 60

14. Harder sand rock . 0 0 0 0

0 60

94

130 Sand, with small amount of water 0

0 94 104

12. Clay, light in color

0 104 107

llo Sand 0 o . o 0 0

0 107 111

100 Clay, light in color 0

0111 117

90 Hard sand 0 0 0 0 0

. 117 126

8o Red clay 0 0 0 0 0 0

. 126 136

7o Sand, water-bearing

0136 145

6. Red clay 0 0 . 0 0

0 145 155

5. Sand, water-bearing

0 155 158

40 Yellow clay

0 158 160

30 Sand rock 0 0 0 0 0

0 160 173

Basement rocks

20 Decayed top of crystalline rock

0 173 202

1.

Hard crystalline rock

0

0

0 202 261

Log of Well No. 2fi lorafcd about 4.000 fccf soufl1cast of 1\'ell No. 11.

Pleistocene (terrace deposit)

Feet

270 Clay 0 0 0 0 0 0

0 17

26o Sand and gravel 0

17 27

Lower Cretaceous

250 White sand rock 0

27 31

240 Brown sand rock

31 38

23. White sand rock

38 46

220 Brown sand rock

46 55

210 Gray sand rock 0

55 69

200 Brown sand rock

69 77

190 Yellow, sandy clay, soft and sticky

77 98

180 White sand, water bearing 0 0 0

98 117

170 White sandy clay, sticky like putty 0

0 117 125

16o Dark yellow clay

0125 134

150 Blue sandy clay

0 134 142

14o Yellow clay . 0 0

0 142 147

130 Blue sandy clay 0

0 147 156

120 Red clay, shaly 0

0156 165

120 White sand, small amount of water 10. Red clay, shaly 0 0 0 0 0 0 0 0 0

0 165 179 0179 190 .

90 Yellow sandy clay 0 0 0. 0 0 0 0 0

0190 194

80 White coarse sand, water bearing

0 194 210

7. Red clay, shaly 0 0 0 0 0 0 0 0 0

0 210 215

6o Yellow sandy clay 0 0 0 0 0 0 0 0

0 215 220

50 Gray sandy clay, lead color . 0 0 0 0 0 0 0 0 0 0 220 229

40 Tough, micaceous clay resembling residual mica

schist 0 0 0

0 229 234

30 Micaceous silt 0 0 0 0 0 0 0 . 0 0 o

234 245

Basement rocks

20 Soft gray decomposed crystalline rock 0

0 245 2:50

1o Hard crystalline rock 0 0 0 0 0 0 0 . 0 0

0 250 267

S2

GEOLOGY OF THE COASTAL PLAIN

~tt Thomas Bluff, one mile below the mouth of Bull Creek, Lower Cretaceous materials are exposed as described in the following section:

Section at Thomas Bluff, Chattahoochee River, Georgia, one mile below the mouth of Hull Creek, left bank. (See plate VII, A.)

Pleistocene (terrace deposit)

Feet

2. Sandy loam at top grading down into sand with a

band of gravel along base . . . . .

. . 30

(Unconformity)

Lower Cretaceous

1. Light gray and greenish gray compact, very arkosic,

micaceous, coarse sand with many pebbles up to 1

inch or more in diameter, and in one layer 7 or 8 feet

above base water-worn chunks of greenish gray, mi-

caceous clay up to 8 inches in diameter. The sand

shows decided cross-bedding at many places . . . . 22

~tt a point about five ancl one-half miles below Columbus, and onehalf mile belmY the mouth of Brickyard Creek, right bank, the base of the bluff at low water exposes about six feet of Lower Cretaceous purplish sand and clay. This is overlain by 25 or 30 feet of Pleistocene terrace materials. The upper surface of the Lower Cretaceous beds slopes dmYn stream and in a distance of about one-quarter mile passes beneath water level, the bluff below this point presenting Pleistocene strata from top to base. The Pleistocene materials consist of loam, sand, and gravel, having a total thickness of 35 feet. The gravel forms the basal portion of the section, the bed reaching a maximum thickness of 12 feet in places.
From this point to the mouth of Upatoi Creek, vvith the exception of a few low exposures of Lower Cretaceous clay, the bluffs present only Pleistocene strata, in places showing heavy beds of gravel in the basal portions.
The Entavv formation, which oY~rlies the Lower Cretaceous terrane in this region, makes its first appearance on the river in a bluff a short distance below the mouth of Upatoi Creek. The character of the materials and the relations of the formations are described and
figured below.

/'!'rtion l;rloll' the mouth of Upatoi Crerl. (171nffn},oorlu'l' f?irer. nine miles below Columbus, left bank.

Pleistocene (terrace deposits) 4. Sandy loam, grading down into clay and this in turn into sand . . . . . . . . . . . . . . . . . . . . . 3. Sand and gravel with cobbles at base up to 6 inches in diameter. Also occasional pieces of petrified wood, and one large petrified log in gravel near base . . . . . . . . . . . . . . . . . . . . . . . (Unconformity.)

Feet H
7

LOWER CRETACEOUS

83,

Upper Cretaceous Eutaw formation
2. Dark gray, finely arenaceous and micaceous clay with occasional grains of glauconite, containing a few poor impressions of pelecypods near top. Contains iron carbonate concretions with poor shell impressions, and occasional pieces of lignite _ . . . , 1 to 5
(Unconformity) Lower Cretaceous
1. Light greenish gray, sandy, micaceous clay, to water's
edge . . . . . . . . . . . . . . . . . . . . . . . . 0 to 3

A sketch of the face of bluff where the precedin(J' section \Yas made

is given in fig. 7.

,

o

"~::=:d~&:0}~]@T~1&llt.~:~:'g,~~,;.

~---,-----100 1 -----~
Fig. 7.-Sketch showing relation of Lower Cretaceous beds to Eutaw formation at bluff be,low mouth of Upatoi Greek.

The last exposure of Lower Cretaceous strata seen in descending the

river is in a bluff on the left bank at Broken Arrow Bend, 10lj2 miles below Columbus. Characteristic arkosic sands and clays form the

base of the section, rising four or five feet above water level at one

or two places along the face of the bluff. They are overlain uncon-

formably by laminated sands and clays and fossiliferous marine sands

of the Eutaw formation.

Region beiU'cen Chattahoochee and Ocrnulgee Rivers.-Xnmerous

exposures of Lower Cretaceous strata occur east of Chattahoochee

Iliver in J\fuscogee County, and in the extreme northern part of

Chattahoochee County. A number of sections have been examined,

some of 'vhich show the relations of the beds to the underlying base-

IIIent rocks, and some to the overlying Eutaw formation.

The beds described in the section given below appear in a road cut

of the Columbus-JYfacon road at the eastern edge of the city of Co-

lumbus. Section on Colt~rnbus-Macon road, a short distance east of Wercoda

Creek, near the eastern outskirts of Columbus, Ga., on the face of

the scarp separatinq the first and second Pleistocene terra~e plains.

Pleistocene. (Second terrace above river.)

Feet.

~- Sandy loam and sand . . . . . . . . . . . . . . . . 15 or 20

(Unconformity.)

Lower Cretaceous

3. Fine, arkosic, micaceous sand . . . . . . . . . . . .

4

2. Light gray, stratified, coarse, very arkosic, micaceous

sand, streaked with iron stain. The kaolin grains

reach a maximum of :14 inch in diameter . . about .

7

L Gray or drab clay, not well exposed . . . . . . . . .

il

84

GEOLOGY OP THE COASTAL PLAIN

A remnant of Pleistocene terrace deposits consisting of reddish and yellowish, argillaceous, pebbly saud, IYith gral'el band along the base, rests unconformably upon the Lmn'r Cretaceous strata on the face of the scarp at the preceding locality.
An exposure exhibiting an indurated phase of the coarse, arko~i(; sand of this terrane occurs on the Columbus-.:\Iacon road, three ;md one-half miles northeast of Columbus. The section is describe<l b<.'low. (See plate VII, B, opposite page 88.)

Section on Colu m bus-Jfaron road, three and onr-71{(/f milrs northeast

of Columbus, Ga.

Lower Cretaceous

Feet

3. Light gray, extremely coarse, very arkosic, pebbly

sand, the sand grains and pebbles angular. The

pebbles consist principally of quartz, reaching

maximum diameters of several inches, but tnere is

a considerable intermingling of feldspar fragments.

Along the base occur large chunks of mechanically

introduced clay . . . . . . . . . . . . . . . . . . 10

2. Light gray, very coarse, friable, arkosic sandstone,

with texture similar to preceding . . . . . . . . . 5

1. Light gray, somewhat finer, compact arkosic sand . 2

The road to the northeast of the preceding exposure passes up a hill abt~mt 50 feet in height in a distance of one-quarter mile. Poor exposures in the road ditches reveal materials similar to the preceding with subordinate elay lenses. Coars(" grawls appear in the 1'tpper part of the section, but whether these should be referred to the LO\nor Cretaceous or to a younger surficial formation has not been ascertained.
Gravels similar to those just mentioned cap the hills to the west and east of Cooper Creek on the same road.. The body of these hills is made up of Lmver Cretaceous coarse, arkosic sands and sandy c1ays. Small exposures of the formation occur along this road still farther to the northeastwar<l. At a point seven miles northeast of Columbus the contact of the formation with the m1<lerlying basement crystallines appears in a road ditch expmmre. ;\ ,;ection made at thi~ plare
is given below.

Section, Colwnlms-]}facon road. 7 mi/r.s northeast of Columb11s. Ga.

Lower Cretaceous

Feet

3. Argillaceous sand and gravel with creep gravel ex-

tending a considerable distance down the hill

slope . . . . . . . . . . . . . . . . . . . . . . . . 10

2. Coarse arkosic sands with subordinate sandy clay

lenses, about . . . . . . . . . . . . . . . . . . . . 40

(Unconformity.)

Basement rocks 1. Decayed crystalline rock, apparently a gneiss, with

quartz veins . . . . . . . . . . . . . . . . . . . . 3

LOWER CRETACEOUS

85

On the Columbus-Cusseta road, one and one-half miles southeast of the bridge over Bull Creek, and about four and one-half to five miles southeast of Columbus (see topographic map, Columbus quadrangle), where the road leads up from the first Pleistocene terrace to the upland, the strata making up the hill are exposed, in part poorly, from the base to the top, making in all a thickness of about 140 feet. The lower 20 feet, consisting of coarse, cross-bedded, more or less m;kosic sand, is referable to the Lower Cretaceous. The remainder of the section with the possible exception of the upper 18 feet, which may belong to a younger surficial formation, is classed with the Eutaw formation. The strata consists largely of sands and clays of marine ongm. The contact between the Lower Cretaceous beds and the Eutaw formation is somewhat obscure owing to the resemblance of the sands of the former to the sands forming the basal beds of the latter. It is believed, however, that unconformable relations exist between the two divisions and that this unconformity represents an important time hiatus. (See detailed section, p. 124.)
Exposures of the formation were observed along the Steam Mill road running a little south of east of Columbus (first road south of the Buena Vista road, see topographic map of Columbus quadrangle), but most of these are small and unimportant. One, however, seven miles from Columbus, where the road passes up the westward facing slope of Tiger Creek Valley, presents phenomena of interest. The hill here is 100 feet high above the creek valley. The lower 80 feet of the section consists of light colored, coarse, irregularly bedded, arkosic sand, with subordinate light clay lenses. This is overlain, probably unconformably, by beds of the Eutaw formation which make up the upper 18 or 20 feet of the section. (See detailed section, p. 124.) The contact between the Lower Cretaceous strata and the Eutaw formation is rendered somewhat obscure by similarity of materials and weathering, but its approximate position is marked by an irregular line of iron crusts.
Other less conspicuous exposures of characteristic Lower Cretaceous materials were observed for several miles to the eastward along this road. On the divide between Steam Mill Creek and Wolf Creek there is a relatively thin capping of weathered marine materials of the Eutaw formation resting upon the Lower Cretaceous beds.
In the extreme northern part of Chattahoochee County the northward facing bluffs of Upatoi Creek exhibit Lower Cretaceous strata in their basal portions, their upper parts being made up of Eutaw beds. These were studied at three places as described below.
Just above the bridge of the Columbus-Lumpkin road, seven and one-half miles south of Columbus, the base of the bluff from the

86

GEOLOGY OF THE COASTAL PLAIN

water's edge to a height of 10 feet i::; compw.;eJ of light gray, compact

sands and clays, referable to the Lower Uretaceous. These are over-

lain by dark, calcareous marine sanJs and clay::; of the Eutaw forma-

tion. Although the latter formation is not marked at its base by a

conglomerate the contact with the unJmlying formation is sharp, the

change in the character of the materials being abrupt. It is belieYed

that unconformable relations exist.

,

The seconJ place examined is at a point one-quarter mile below

the Columbus-Uusseta road bridge, and about seven miles southeast

of Columbus. The bluff is 90 feet high. The upper +O feet of the

section consists of fossiliferous marine sands and clays of the Eutaw

formation. Below this occur 20 feet of light gray, coarse, cross-

bedded, in places arkosic, sand, more or less streaked with yellow,

with some sandy clay layers, referable to the Lower Cretaceous. At

the time examined the basal 30 feet was covered by talus. The ~on

tact between the Lower Cretaceous and Eutaw formation was some-

what obscure owing to talus and vegetation. (See detailed section,

p. 126.)

Just above :JicBride Ford, 11 miles south of east of Columbus,

air-line distance, the creek bank presents another instructive section,

the details of which are clescrilw(l below. (See also p. 127 of this

report.)

Section, Upatoi Creek, just above McBride Ford, 11 miles south of

east of Colwnbus, Ga.
Feet

Pleistocene (terrace deposit). 3. Principally sand with a gravel band along base .

. 10 to 12

(Unconformity.) Upper Cretaceous
Eutaw formation. 2. Irregularly bedded, coarse, arkosic, crossbedded sand, with subordinate chocolate to black clay lenses. The sand is in places full of small angular quartz .pebbles and some feldspar fragments, the basal portions being especially coarse. The materials

contain considerable lignite, some of which is in the form of fairly large logs. The clay lenses contain leaf impressions, for the most part imperfect.

In one dark clay lens, 6 to 10 inches thick, however, near the lower end of the bluff, a number of well preserved species were found . . . . . . . . 12 to 15

(Fnconformity.)

Lower Cretaceous 1. Light gray, arkosic sand, and drab clay breaking with hackly fracture . . . . . . . . . . . . . . . . 0 to 5

The unconformity separating the Lower Cretaceous and Eutaw

becls is fairl;v sharp and easily traceable for several hnndrecl feet

alono- the bluff although the materials above and below thP contact

b

'

'

LOWER CRETACEOUS

S7

do not differ markedly. The line of contact undulate:; along the

face of the bluff, varying from low \Yater level to tive feet above that

datum. The plants found in the clay lenses above the contact are

characteristic Upper Cretaceous forms. A list of the species from

this locality with the description of one new species has been pub-

lished by E. \V. Berry.' If the reference of the basal beds of the

section to the Lower Cretaceous is correct the unconformitv at this

point represents an important time hiatus.

"

The Lower Cretaceous terrane is present in Talbot County in a

belt paralleling the southern boundary of the county three to six

miles in width. The formation rests unconformably upon a base-

ment of crystalline rocks. The following log of a well located one-

half mile east of Geneva has been obtained. J. F. Downs, the owner,

is authority for the lithology.

'

I

Log of well located on "A very high elevated place 100 yards from

Central of Gemgia," Talbot County.

Lower Cretaceous

Feet.

1. Hard, red gravel with some "chalk" (white clay) and

some sand, water-bearing in lower 5 feet . . . . . . 0 to 50

. Veatch describes a section two miles southeast of Geneva in which

the several strata of sand and clay arP ind1uated. It is copied as

follows: (Clay Report, p. 228.)

Feet .

6. Clay . . . . . . . . .

. 3

5. Soft sandstone . . . . . .

. 15

4. Jointed, purplish clay, indurated . .

. 6

3. Soft, yellow sandstone . . . . . . . . . . . . . . . .

. 20

2. Purplish, hard-jointed clay, with large quartz grains

. 5

1. Soft, yellow, crossbedded .sandstone . . . . . . . . .

. 20

Veatch states that south \\'anl from the preceding, "The section 1s overlain by a loose, brmn1 or yellow sand, belonging to the Upper Cretaceous (Eutaw)." (Clay Report, pp. 228-229.) He also says, "North and west of Geneva near the contact with the crystalline rock the material composing the Cretaceous is coarse and the clay is brilliantly colored by iron." (Clay Report, p. 229.) He mentions white sandy clays referable to this formation near Junction City. Beds of this formation are believed to be present along Juniper Creek in the extreme northern part of Marion County, but detailed information has not been obtained.
Lower Cretaceous beds are present in Taylor County in a belt several miles wide running east and west through the central part of the county. There is but little detailed information concerning individual outcrops. The formation rests with no'nconformable rela-

'Bnll. Torr~y Botan. Club, No. 37, 1!llO. pp. 503-511.

88

GEOLOGY OF THE COASTAL PLAIN

t.ions upon crystalline basement rocks and is believed to be overlain unconformably by 1Jpper Cretaceous sands and clays.
The following data are taken from Veatch's clay report. (pp.
223-224.)
"Sands of both the Upper and Lower Cretaceous occur in this county and are clay-bearing. The sands of the Lower Cretaceous are not easily distinguished from those of the Upper Cretaceous, and the white clays of both are similar in occurrence, but those in the vicinity of Butler, in the Tuscaloosa lLower Cretaceous, but not Tuscaloosa] are purer and more extensive than elsewhere in the county.
"North of Butler the sand is noticeably coarser and more pebbly than south; there are beds of coarse, granular quartz pebbles and occasionally some feldspar pebbles; and at one point, a hard clay-arkose breccia, similar to that noted at Grovetown and Hephzibah, was found."
The log of an 80-foot well at Reynolds is given below. The description of the beds penetrated ''ias furnished by the owner, A. J. Craw-
ford.

Log of well located 600 ya!f'ds southeast of the postoffice at Reynolds" Ga. Elevation at mouth, 4-33+ feet.

Lower Cretaceous
5. Sandy soil . . . . . . . . . . . . . . 4. Clay . . . . . . . . . . . . . . . . . 3. "Chalk" (white clay) and clay . . . 2. Coarse sand with some water at base . . . . 1. Alternating layers of clay, rock, and mud, fur-
nishing a small amount of water at base . .

Feet.
1 to 4 4 11 11 23 23 33
33 80

About the southern one-half of Crawford County is underlain by Lower Cretaceous strata, the belt of outcrop averaging four or five miles in width and extending in a general northeast-southwest direction. The lower and upper relations are the same as in the preceding county. Upper Cretaceous strata overlap the Lower Cretaceous beds in a strip several miles wide along the southeastern border of' the county. There are several interesting exposures within this area.
Rich Hill is a prominent hill about five mile~ southeast of Roberta. Its elevation above sea level is estimated from aneroid readings to be something over 600 feet. Deep gullies have been washed in the slopes of the hill both on the north and south sides. Cretaceous beds make up the basal 30 feet of the exposed portion of the hill, the overlying beds constituting an Eocene outlier. The following section was
made in one of the southward-facing gullies.

GEOLOGY OF THE COAS7'AL PLAIN OF GEORGIA.

PLATE VII.

A. THOMAS BLUFF~ CHATTAHOOCHEE RIVER. ONE l\IILE BELOW THE l\iOUTII OF BULL CREEK. l\IUSCOGEE COUNTY, GA., HOWI:"'G LOWER CRETACEOUS STRATA.

B. EXPOSURE IN CUT OF COLUMBUS-MACON ROAD, THREE AND ONE-HALF MILES NORTHEAST OF COLUMBUS. GA.. SHOWING I:"'DURATED LAYER OF LOWER CRETACEOUS ARKOSE.

LOWER CRETACEOUS

89

Section at Rich Hill, jive miles southeast of Roberta. Gully on south

slope of hill.

Eocene.

Feet. In

3. Sand, clay and limestone. (For details see section,

p. 299) 0 0

0

0

0

0

0

0

0

0

0

0

0



0

0

0

0

0

0

0

0

0 97

6

Lower Cretaceous

2. White clay, varying in thickness and texture; very

pure in places . . . . . . . . . . . . . . . . . . . 10

1. White, crossbedded, arkosic, micaceous sand, medium

to coarse in texture, with subordinate lenses of

white micaceous clay reaching 3 feet or more in

thickness . . . . . . . . . . . . . . . . . . . . . . 20

Cretaceous strata are exposed in a series of cuts of the Southern

Hailway from one-quarter mile to about one-mile north of Zenith

Station. The details of this section are given on page 1G7. It will

be observed that clay supposed to belong to the Lower Cretaceous ap-

pears in the base of the three cuts farthest north. This is overlain

unconformably by coarse and fine sands and laminated clays of the

Upper Cretaceous. The Lower Cretaceous clay is massive and putty-

like when wet, and is usually light in color, but is considerably

blotched with pink and purple tints. The correlation of this clay bed

with the Lower Cretaceous is made on the grounds of its lithologic

resemblance to the clays of that formation, and its unconformable re-

lations with the overlying Upper Cretaceous sands and clays. Sim-

ilar clays are exposed in a gully a short distance west of these cuts

on the property of Phil Ogletree.

A well on the property of Phil Ogletree, one mile northwest of

Zenith, exhibits the following strata,. the mvner being authority for

the lithology as given.



Section of well one mile northwest of Zenith.

3. Red clay . . . . . . . . . . . .

?

2. White kaolin (clay) . . . . . .

?

1. Sand and gravel water-bearing .

?

45
The white clay and the water-bearing sand and gravel probably belong to the Lower Cretaceous.
A well owned by Isaac :Miller, four and one-half miles northwest of Fort Valley, in Crawford County, having a depth of 103 feet, penetrated, at its base, three feet of white clay, which is questionably referred to the Lower Cretaceous. (See section p. 168.)
A well owned by vVm.' .T. Dent, one-quarter mile southwest of ~o berta, is said by the owner to have been dug through hard clay with streaks of whit~ "chalk" (clay) and to have obtained water from sand

90

GEOLOGY OP 'THE COASTAL PLAIX

beneath the clay at a Jepth of 42 feet. The beds penetrateJ should proba.bly be referred to the Lower Cretaceous.
The Lower Cretaceous terrane is present over about the southeastem two-thirds of Bibb County, either at the surface or immediately beneath thin surficial deposits belonging to later formations. The formation rests upon crystalline rocks and is believed to be unconformably overlain along the southern border of the. county by Upper Cretaceous sands and clays. ..-'tn excellent exposure may be seen on the Central of Georgia Railway at Rutland, r;ix and one-half miles sonth of :Macon. The section is as follows;

Section at Rutland. Ga., 1:11 r11t of Central of Gern.r;ia Railway.

Pleistocene. 4. Yellow. red, and mottled, weathered, sandy clay forming a fairly definite band along the top of the section. At south end of cut separated from underlying sand by iron crust one inch thick . . . . . 3. Coarse, pebbly, gray to red argillaceous sand with small lenses of pebbles, forming a fairly well defined band . . . . . . . . . . . . . . . . . . . . . 2. Fairly well-defined band of yellowish and reddish gravel with coarse sand matrix and with interspersed lenses of coarse sand. Locally indurated to a conglomerate or coarse sandstone. The pebbles are mostly angular or slightly waterworn, and reach a maximum of 4 or 5 inches in diameter . .
(Undulating unconformity.) Lower Cretaceous
1. Pale yellow or cream to almost white, massive finely arenaceous, micaceous clay, grading laterally at the north end of the cut into white or cream, crossbedded coarse, extremely micaceous sand . . . . .

Feet. 5 to 7 5 6
6 10
3 8

Other cuts within one-half mile to the northward show materials with relations similar to the preceding. In a cut of the same railroad, :four and one-half miles south of Macon, the following section is revealed.

Section in cut of Central of Georgia Railway, four and one-half miles
south of Macon, Ga.
Feet.
Pleistocene. 3. Coarse, yellow, rather loose sand . . . . . . . . . . 2 to 3 2. Mottled red, yellow, and gray, very coarse, crossbedded, pebbly sand with irregularly distributed gravel lenses. Pebbles mostly angular, some fairly well rounded, reaching a maximum of 3 or 4 inches in diameter . . . . . . . . . . . . . . . . . . . . 2 5 (Unconformity undulating 5 to 10 feet above base.)
Lower Cretaceous 1. Very coarse, cross-bedded, sharp, light gray, argillaceous sand streaked with yellow, with local lenses of white clay and scattered clay balls . . . . . . . 5 10

LOWER CRETACEOUS

91

One and one-half miles south of the station at :Macon a cnt of the Central of Georgia Railway reveals a section as described below:

Sec.tion at overhead bridge, Central of Georgia Railway, one and

one-half miles south of JIaeon.

Pleistocene.

Feet

3. Reddish sandy clay . . . . . . . . . . . . .

5

2. Mottled yellow and red, argillaceous sand with scat-

tered pebbles at the top, becoming more pebbly and

grading into a gravel bed with sand matrix at base. (Unconformity, slightly undulating) Lower Cretaceous

5 toG

1. Cross-bedded arkosic, argillaceous sand . . . . . . 6 to 7

_Exposures similar to the preceding occur for one-quarter mile north of the overhead bridge. Less important exposures of Lower Cretaceous strata occur at various places in the vicinity of:Macon.
Otto Veatch furnishes the following information concerning occurrences of the formation in this county west of Ocnmlgee Rin'r. (clay report, pp. 207-208.)

"At a point on the lower river public road, five miles below Macon, six
feet of white clay is exposed in a cut. It is overlain by a red sand containing thin clay layers and fragments of white clay, and is underlain by white micaceous sand.
"In the western part of the county, along Echaconne Creek, beds of white clay will be found in the Cretaceous sands. But little or no prospecting for clay has been done in this part of the county, and but little is known
concerning these deposits. Judging from the few observations made during field work, the beds are likely to be thin, and stained with iron oxide."

In the region to tlie southwest of Macon, there are remnants of overlapping strata, which are questionably referred to the Eocene.

Region between Ocmulgee and Savannah rivers.-Veatch gives the
following information concerning the materials referable to the Lower
Cretaceous in Bibb County cast of Ocmulgee River: (clay report,
p. 207.)
"In the cuts of the railroads, going east from Macon, good exposures of
white clayey sands may be seen, but the amount of clay is small. * * *."
"A typical occurrence of these clayey sands may be seen in the cut of the abandoned Macon and Augusta railroad, three miles east of Macon."
"At Brovvn Mountain in the southern part of the county, nine miles. from Macon, 110 feet of white, clayey sand is exposed at the base of the hill. This sand is Cretaceous, (Tuscaloosa) [Lower Cretaceous and not Tuscaloosa] and contains thin layers and fragments or pellets of white, pure clay, but no thick beds of kaolin have been found. About two miles south of this point on the Tha.rpe estate, white clay has been found at the base of a fullers earth deposit, but as far as the writer knows no effort has been made to determine its quantity."

The greater part of Twiggs County is covered with deposits of Eocene age. However, in a small area in the western part of the

92

GEOLOGY OP THE COASTAL PLAIN

county the Lower Cretaceous strata come to the surface and in the
north, i~ wha~ is known as the Dry Branch region, an int~resting and
economically Important area of the formation has been produced by the removal of the overlying Eocene strata by stream erosion.
At the pit of the American Clay Company near Eleven Mile Post (east of Macon) the following sncccssion of strata was observed:

Section at pit of American Clay Company, Eleven Mile Post, Ga.

Eocene. Claiborne group.
2. Sand and clay (for details see section, p. 294) . . ( iTnconformity.)
Lower Cretaceous. 1. White to very light gray, massive clay (used in the manufacture of paper) . . . . . . . . . .

Feet. 28
18+

Veatch described the Cretaceous clay at 'this locality as follows:

"The clay is a soft, iron-stained-kaolin, and is sold entirely to paper manufacturers.
"The clay bed is known to attain a thickness. of 18 feet, the upper 10
feet of which is stained more or Jess yellow by iron oxide, while the lower part is a soft, gray, micaceous clay." (clay report, p. 138.)

The plant of the Atlanta Mining & Clay Company is located about one-half mile distant from the preceding locality, on the east side of the tracks of the :Macon, Dublin & Ravannah Railroad. This company is mining a bed of white clay which occupies the same, or ap proximately the same, stratigraphic position as the preceding. Veatch describes this clay as follows:

"A thickness of 25 feet of clay is known to occur, but at present only 8 to 15 feet are mined. The clay bed is for the most part a soft, plastic, white clay. The clay is massive and occurs in a single bed; it is jointed and shows slickensided surfaces, but presents no definite system of jointing, and is slight-
ly stained by iron and manganese oxides along the joint planes. The bed shows variations in thickness, due either to irregularities of deposition or to erosion. The strata here are almost horizontal, and are but little disturbed from their original positions. The clays in the two pits, about 200 yards apart, are parts of the same bed. The clay bed becomes micaceous at the bottom, and is underlain by white sand and gravel." . (Clay Report, pp. 130-131.)

The LmYer Cretaceons clay at this locality is overlain unconform

ably by Eocene strata. For a detailed section see page 294 of this

report.

.

A bed of white clay or kaolin occupying approximately the same

stratigraphic poRition as those previously described, is mined by the

Georgia Kaolin Company, two miles southeast of DryBranch. The

following section describes the strata as they appeared at the time the

pits were visited:

LOWER CRETACEOUS

93

Section at pits of Georgia Kaolin Oornpany, two miles southeast of

Dry Branch.

Eocene. Claiborne group.
2. Sands and clays (for details of section see p. 256) (Unconformity.)
Lower Cretaceous. 1. Massive, white clay or kaolin . . . . .

Feet. 131 18

The unconformable contact separating the Crctaccon~ awl Eocene strata at this locality is shown in the photograph, plate \'I, .\, oppo site page 80.
Veatch describes the LmYer Cretaceous f'lay lwd at the preceding locality as follmn:

"The clay mined occurs in one massive bed, which, in the pit that was being worked during 1907, attained a thickness of 20 feet. This entire thickness is probably as much as 85 per cent. pure clay, and in places the clay occurs in minable quantities as high as 98 per cent. pure without washing.
"The clay, as it appears in the bed and in the moist condition, is a drab or cream color, but becomes white when dry The bed is jointed throughout. and presents slickensided surfaces along the 'joint planes. The clay in the upper part of the bed is a semi-hard to a flint clay, and may be stained slightly along the joint planes by manganese and iron oxides. The manganese is rarely in appreciable quantity and occurs as a very thin coating or stain, or is often in the form of fern-like dendrites. In the upper part of the bed there
are also curious "fingers" and cylinders of sand, penetrating the white clay. This is a phenomenon observed nowhere else in the Dry Branch region, and is difficult of explanation. The "fingers" of sand are usually vertical or oblique, and are not more than one or two inches in diameter. The sand in them is a yellow, coarse quartz, clayey sand, which may be calcareous. and has been observed to contain poorly preserved fossil remains. These "fingers" are not
large nor .very abundant, but detract from the value of the clay where they occur and the upper part of the bed is thrown away as waste, or sold as fire clay and sagger clay. They are confined to the upper two or three feet of the
bed, and are probably purely local and may not be found at all in future work.
"The lower part of the bed is a soft, white, gritless kaolin which is pure enough to place on the market without preliminary washing."-( clay report, pp. 125-126.)

Slight movement along joints in the clay at the preceding locality has been noted by Veatch.
The following data concerning other localities where the formation has been observed in Twiggs County have been abstracted (not quoted) from Veatch's clay report and from his nnpnblishe<l notes: (pp. 142-143, 146-147, 149-152.)
On the property of I. Mandie and Company, two miles south of Dry Branch, 10 feet of white, semi-hard, high grade pottery clay is exposed in a pit at the company's mines. The clay bed is reported to have a total thicknHSS of 15 feet. It is overlain by (Eocene) sand and clay. The relation of the clay bed to the overburden is shown in the following sections:

94

GEOLOGY OY 7'HE COASTAL PLATX

Section in claypit of I. Jfandle and Company, two and one-half miles

south of Dry Branch, Ga.

Eocene.

Feet.

4. Red sand, about . . . . . . . . .

8

3. Drab laminated clay, about . . . .

2

2. Gray and yellow sand with white clay fragments

near base. Fossiliferous. . .

5 to 10

(Unconformity.)

Lower Cretaceous.

1. White, semi-hard, jointed clay

. 10 to 15

At the pit of the old Rico Kaolin Mine, one and one-half miles east of Philips Station, a white Cretaceous clay bed with relations as shown in the following section is exposed:

Section at old Rico Kaolin Mine, one and one-half miles east of Philips Station.

Eocene. Claiborne group. 2. Red sand, containing white clay fragments and fragments of clay having a concretfonary or bauxitic appearance . . . . . . . . . . . . (Unconformity.)
Lower Cretaceous. 1. White clay, micaceous in the upper 8 feet with a micaceous, argillaceous sand lens several feet thick at one end of the section . . . . . . . .

Feet. 8 to .10
16

In the vicinity of Bond's store (Delzell P. 0.) there are numerous occurrences of white clays, the beds ranging in thicknef's from 10 to 30 feet.
Four feet of bluish white, plastic clay was encountered in a well on the property of Monroe Phillips at Reids Station, the bed being 18 feet below the surface. This probably belongs to the Lower Cretaceous.
Twelve feet of light, cream-colored clay, probably referable to this formation, outcrops on the property of Mrs. S. Napier, one-half mile south of Myrick Mill, five miles north of Jeffersonville.

For further information concerning the Dry Branch region see Veatch's paper, "The Kaolins of the Dry Branch Region, Georgia," Economic Geology, Vol. 3, 1908, pp. 109-117.
The Lmver Cretaceous terrane is present in the southeastern onefourth of Jones County. It rests upon a foundation of ancient crystalline rocks and is overlain unconformably over a part of the area by Eocene strata (Claiborne group).
Veatch, in his clay report, has described LmYer Cretaceous strata near Gris-woldville, on the property of J. R. Van Buren (pp. 153158). The substance of the geological data in this acconnt is givPn in the follmving three paragraphs:

The main exposure is in a cut of the Central of Georgia Railway one and one-quarter miles west of the station. This cut' is 200 yards long and 40 feet deep. The materials consist of irregularly bedded, gray, arkosic and micaceous sands, and white, drab, and bluish gray clays. The clay beds are in the form

\

LOWER CRETACEOUS

95

of lenses six to ten feet in thickness. Towards the east end of the cut the

Lower Cretaceous beds are overlain with apparent unconformity by red sands

believed to be referable to the Eocene (Claiborne group).

'

In a cut three miles west of the station a white clay bed four to ten feet

thick is exposed for a distance of 500 yards. A similar white clay bed eight

feet thick is exposed one-quarter of a mile south of the Van Buren property.

In the vicinity of Roberts Station, gray, micaceous, kaolinic sand of the

Lower Cretaceous occurs resting unconformably upon decomposed crystalline

rocks and overlain unconformably by sands and clays, in part fossiliferous, of

Eocene age (Claiborne group). These Eocene beds have been traced

southeastward, capping a Cretaceous ridge, to the cut one and one-quarter

miles west of Griswoldville, above described.- (See p. 282 of this report.)

J\fr. J. R. Van Buren is authority for the lithology as described in the following log of a well on the property of the ,J. R. Van Buren
Company, one mile north of Griswoldville:

Log of well one mile no1'fh of Gn:swoldville, Ga.

Lower Cretaceous
5. Sand, about . . . . 4. White clay . . . . . 3. Red clay . . . . . . 2. Sand, water-bearing, about . 1. White clay, about .

Feet.

0

il

?

?

78

. 78 84

Lower Cretaceous strata underlie practically all of \Yilkinson County. Over a large part of the county, however, the Lower Cretaceous beds are overlain unconformably by Eocene strata. Porters Creek, Commissioners Creek, and Oconee River have cut through the Eocene deposits, bringing the Lower Cretaceous to the surface along the sides and bottoms of their vallc>ys. The Eocene beds rcach a thickness .of 135 feet or more on the in'tervening divides.
The following data concerning occurrences of the formation in this county haYe been ahstl'acted (not qnoted) from VeatC'h's C'la.v report, pp. 159-172:

On the property of J. W. Huckabee one mile west of Lewiston, near the Central of Georgia Rail~ay, a white clay bed three to twelve feet in thickness
has been mined to a limited extent. The clay is overlain by ten to twenty feet of sands and fossiliferous, siliceous beds resembling quartzite of Eocene age (Claiborne group).
On the Z. T. Miller place, three miles south of Gordon, a 30-foot bed of white clay appears in a natural exposure. This bed which belongs to the Lower Cretaceous is overlain by tough, plastic, impure clays and red sands referable
to the Eocene (Claiborne group). There are a number of other localities
in the vicinity of Gordon where similar white clays outcrop beneath sands and clays of the Claiborne group, the latter exceeding a thickness of 100 feet in places.-(See detailed sections on pp. 276-277 of this report.)
White cl:hs occur at a number of localities in the vicinity of Mcintyre. Three miles east of this place there are natural exposures of white clay, four to twelve feet thicJ;. overlain by 30 to 50 feet of red sands and impure clayf. of the Claiborne group.
A J:>ed of serni.h~rrl ,,hite C'hl~- reaching a maximum thickness of :lO feet outcrops on the Hatfield property one and one-half miles west of :Mcintyre,

96

GEOLOGY OF THE COASTAL PLAIN

on the south side of the Central of Georgia Railway track. The exposure occurs at the base of a ridge, the overlying strata consisting of Eocene ( Claiborne) sands and clays.
Three miles northwest of Mcintyre, on the property of Robert Billion, 12 feet of soft, white and cream-colored kaolin outcrops in a deep gully, oppo site the residence of William SnQw, beneath 40 feet of Eocene sands and clays (Claiborne group).
On the George Bentley property, two and one-half miles north of the 159th mile post of the Central of Georgia Railway, 12 to 15 feet of white and cream-colored clay is exposed in a roadside gully.
White clay beds occur in the region immediately to the north of Toomsboro, and in a cut of the Central of Georgia Railway at Beech Hill, four miles east of Toomsboro,
Yeatch furnishes the following unpublished note on occurrences
of Lmver Cretaceous clays in the vicinity of Irwinton:
''Irwinton is situated on a high Tertiary ridge capped with red sand. The C:'etaceous is exposed in the valleys 150 to 200 feet lower.
"On the Tolar place, four miles' south of Irwinton, and on Big Sandy Creek, hard white clay, 20 feet thick, is overlain by Tertiary clay. On the basis of this white clay bed the Cretaceous is mapped along Big Sandy Creek almost to Stephensville.
"There is a suggestion that there is one continuous bed of white clay underlying a large area in wilkinson and Twiggs counties. This clay bed, which is known to reach a thickness of 30 feet or more, has been observed at a number of localities to the north and west. It is characterized by its purity, freedom from any large amount of sand, absence of bedding or lamination, and absence pf anything that suggests marine conditions. With the possible exception of South Carolina, these heavy white clay beds have no counterpart in any other portion of the United States."
One-half mile \vest of Irwinton the follo,ving section of a well on the property of D. H. Howell was obtained, the authority for the
lithology being the owner:

Section of well located at foot of high hill.

Lower Cretaceous.

Feet.

3. Clay . . . . . . . . . . . . . . . . . . . . about 0 18

2. Kaolin . . . . . . . . . . . . . . . . . . . about 18 53

1. Layer of rock, water from beneath rock . . . . . . 53 59

"\t nearly all of the localities described on preceding pages the Lower Cretaceous sands and clays are overlain unconformably by sands and clays of Eocene age (Claiborne group). (See detailed sections of Eocene strata in \Vilkinson Connty on pp. 276-278 of this
report.) Locallv the ,vhite, Lower Cretaceous clays of Wilkinson County
have bee'u altered to bauxite. The known bauxite occurrences have hcen studied bv Otto Veatch, and have been treatPrl in some detail h.v him in his cla~ report. (Appendix D, pp. 180-447.) The bauxite, ilO far as discmered, occurs at the top of the I,m\er'Cwtaceous terrane

GI-JOLOGY OF' T HE COASTAL PLAIN O P GEORGIA .

PLATE V lll

LOWER CRETACEOUS

97

immediately beneath its contact with overlying Eocene sands and clays.
The principal localities where the ore has been found are in the vicinity of Toomsboro, Irwinton, Mcintyre, Gordon, and Cooper Station.
Portions of the southern and eastern parts of Baldwin County are underlain by Lower Cretaceous strata. The beds rest upon crystalline basement rocks and are overlain in a limited area in the vicinity of Stevens Pottery by overlapping Eocene beds. The bi:lst known occurrences are at Stevens Pottery, eight and one-half miles south of Milledgeville, where they are many good exposures. These show a great horizontal variation in the character of the materials. The following section describes the several strata as they appeared in the main pit east of the railroad at the time examined:

Section in main pit at Stevens Pottery, Ga.

Eocene.

4. Red, argillaceous sand, mottled in places. : . . .

(Unconformity.)

3. Mottled pinkish and yellowish, argillaceous sand

and sandy claY . . . . . . . . . . 2. Red, crossbedded, ferruginous sand containing
along base a few quartz pebbles and white siliceous clay pebbles . . . . . . . . . . . . .

(Unconformity.)

Lower Cretaceous.

.

1. White, more or less sandy, massive clay, used prin-

cipally in the manufacture of fire brick, sewer

pipe, etc. . . . . . . . . . . . . . . . . . . .

Feet. 4 to 5 10 to 15 12 tJ 15
10

In an abandoned pit on the west side of the railroad track the following section was made:

Section in abandoned pit, nest side of railroad track, Stevens Pottery, Ga.

Eocene.
2. Coarse, yellowish and gray, arkosic, crossbedded sand, with boulders along base consisting of white clay penets in a darker drab clay matrix. There are also .along the base white, rounded, silicified clay pebbles and some quartz, garnet and hornblende pebbles . . . . . . . . . . . . . . . . . (Unconformity.)
Lower Cretaceous. 1. Light to white, arkosic sands with lenses up to six or eight feet in thickness, of white clay, more or less sandy and micaceous. Locally, especially near base, there are irregular iron concretions . . . .

Feet. 8 20

98

GEOLOGY OF THE COASTAL PLAIN

About ~ne-quarter mile south of the station at Stevens Pottery, on the west s1de of the railroad track, the Lower Cretaceous arkosic sands and white clays are seen to be overlain by markedly unconformable olive-green, harsh, siliceous, and probably calcareous clay, which is certainly referable to the Eocene (Claiborne). Along the base of this green clay are numerous pebbles of quartz, silicified clay, garnet, and hornblende, and small boulders of pisolitic clay.
Veatch, in his clay report, has described the clays at Stevens Pottery from the standpoint of their economic value (pp. 172-174).
A well drilled at this place passed through the Lower Cretaceous beds and entered the underlying basement crystallines at a depth of about 75 feet beneath the surface. The latter, consisting of a decomposed granite rock, was penetrated to a depth of 175 feet. The authority for this data is W. C. Stevens, of Stevens Pottery, Ga.
One and one-half miles a little south of east of Milledgeville, a few feet of coarse, cross-bedded, arkosic sand was observed in a roadcut on a hill slope, resting in a shallow depression in deeply decayed crystalline rocks which compose the body of the hill to its summit. The hill is about 125 feet high and the sand deposit is well down toward its base. This bed is believed to be a Lower Cretaceous remnant. Overlying the sand with .apparent unconformity is a surficial covering, three or four feet thick, of coarse sands and gravels of uncertain age.
Lower Cretaceous strata have a limited areal distribution in the western and northern parts of \Vashington County. They are overlain by Eocene strata and would not appear at the surface were it not for the erosion which has produced the valleys of Oconee River, Buffalo Creek, and Ogeechee River.
Veatch has noted a number of occurrences of the formation in this county. The following data has been adapted (not quoted) from his clay report, pp. 176-179, and from pp. 274-276 of the present report:

Ten miles north of Oconee on the property of Mrs. S. M. Gilmore, 15 feet

of white clay is overlain by 20 or 30 feet of red mottled sand.

Six miles west of Sandersville, on the upper Milledgeville Road where it

descends to Keg Creek, 16 feet of hard, massive, white fire-clay of Lower

Cretaceous age is overlain unconformably by 125 feet of Eo.cene sands and

clays.

At the old Carter Mill site, five and one-half miles north of Sanders-

ville, six feet of massive, white fire-clay outcrops beneath Eocene sands and

clays sive,

~haintde

one mile fire-clay

north of this mill there is an outcrop of 12 feet of showing similar relations to the Eocene sands and

mas clays

above. This clay bed is underlain by typical Lower Cretaceous sands.

On the road to Hebron, seven miles southwest of Sandersville. four feet

of white clay outcrops at the base of a hill beneath 90 feet of Eocene sands

and clays. The same relations were observed in a cut two miles southwest

of Chalker.

LOWER CRETACEOUS

99

One mile south of Chalker on the public road, white and yellow sands referable to the Lower Cretaceous are overlain by 80 feet of Eocene sands and clays.

Lower Cretaceous sediments are present over much of the southern half of Hancock County. The total thickness of the beds is not great since the basement rocks upon which they rest appear in the valley bottoms of many of the streams. In limited areas in the southeastern part of the county overlapping Eocene strata rest upon the Lower Cretaceous beds.
The best exposures of the formation in Hancock County are in the first two cuts of the Georgia Railroad, a short distance southwest of Carrs Station. At several places the contact .with the underlying basement rocks, which consist of deeply decayed granite and schist, is visible. The line o contact is very uneven, varying from below the level of the track to a maximum of 12 feet above that datum. The maximum thickness of materials exposed is 50 or 60 feet. The Lower Cretaceous materials consist of light-colored, coarse, crossbedded, arkosic sands with interstratified lenses o light to white clays, the latter reaching a maximum thickness of 10 or 12 feet, and with clay boulders and clay balls scattered somewhat irregularly through the sands. The most prominent lens of white clay is at the north end of the first cut. This bed has a maximum thickness of 10 or 12 feet, but is replaced by sand a short distance away laterally. Near the base of this lens and about eight feet above the track level, a few, taint, indeterminable lea impressions were observed in soft, mealy, laminated clay. This is the only known occurrence of leaf remains in this formation in Georgia. In the second cut there is a very conspicuous unconformity, 30 to 40 feet above the track level, probably local within the Lower Cretaceous strata. The materials above this unconformity consist of coarse, yellow, cross-bedded sands with gravelly layers near the base, the whole presenting a darker appearance than those beneath. A similar unconformity may also be seen at one place in the first cut; here above the contact, in the base of the overlying darker sands there are large boulders of white clay. In both cuts a few feet of loose, gray, surficial sands overlie the older materials. This locality has been described by Veatch in his clay report (pp. 204, 205, Pl. 13, Figs. 1 and 2).
Lower Cretaceous strata underlie practically all of Glascock County. The formation is underlain by crystalline basement rocks which are exposed in stream beds at a few places in the northern part of the county, and also at one or two places near the center of the county. It is overlain over much of the area by beds of Eocene age.
The following data relating to this connty have been abstracterl

100

GEOLOGY OF THE COASTAL PLAIN

(not quoted) in part from Veatch's clay report (pp. 180, 181), and in part from his unpublished notes. (See also pp. 273-274 of this rport.)

On the J. Newsome property, three miles east of Gibson, on the roadway leading from Deep Creek to the Newsome residence, is an outcrop of white clay or kaolin which has an overburden of some 75 feet of Eocene sand, clay, and limestone. Borings to determine the extent of the kaolin bed showed an average thickness of 23 feet in a linear distance of 200 yards.
At Jumping Gully Creek on the Gibson-Mitchell road, one mile west of Gibson, ten feet of white clay underlies unconformably 23 feet of sand and clay of Eocene age.
Four miles south of Gibson, at Tompkins Ford, Joes Creek, on the Grange Road, 15 feet of white, massive, semi-indurated clay occupies an unconformable position beneath about 50 feet of clay, sand, and quartzite
of Eocene age. Beneath the white clay bed is a soft clay and sand con glomerate.
Twelve feet of white Lower Cretaceous clay occurs on the property
of J. T. Brady, two miles south of Agricola, and ten feet of similar clay on Big Creek four miles southeast of Agricola.
Exposures of granite rock occur on Joes Creek, two miles south of Beall Spring Station, and also two and one-half miles north of Mitchell.

There are a few small areas in the western part of J e:fferson County, ou Ogeechee River and Rocky Comfort Creek, where Lower Cretaceous strata probably appear at the surface, but detaiied information is lacking.

J. W. Stapleton, of Wrens, Ga., reports that in a well owned by

him, located four miles northwest of Wrens, white clay was pene-

trated from 38 to 48 feet beneath the surface. Water was obtained

in white gravel and quicksand immediately beneath the clay. It is

probable that the clay and the water-bearing materials immediately

beneath the clay belong to the Lower Cretaceous.

Prof. S. W. McCallie1 has published the record of a well located

three and one-half miles southwest of Louisville, having a depth of

1,143 feet. Eocene beds were penetrated to a depth of 350 feet.

Basement rock, consisting of hard, diorite schist was penetrated in

the lower three feet. The materials from 350 to 1,140 feet, con-

sisting of sand, clay, and hard rock, are probably of Cretaceous age,

but whether this whole thickness-790 feet-belongs to the Lower

Cretaceous, or whether a part of the upper portion should be referred

to the Upper Cretaceous can not be determined from the available

data. No Upper Cretaceous strata are known at the surface nearer

than Aiken County, S. C., on the one hand, and western Twiggs

County; Ga., on the other, but it does not seem improbable that beds

of this age exist in this intervening region, buried beneath the over-

lapping Tertiary covering.



Lower Cretaceous strata underlie portions of southern Warren

1Geol. Survey of Georgia, Bull. No. 15, 1908, pp. 128-131.

LOWER CRETACEOUS

101

County. The beds rest unconformably upon the uneven surface of the basement crystalline rocks, which appear at the surface in all the stream valleys. The total thickness of the terrane within the county limits is not great.
Light-colored sands and coarse gravels referable to the formation are well exposed in cuts of the Georgia Railroad, three or four miles southwest of Warrenton. They rest unconformably upon deeply decayed crystalline rocks.
Veatch, in unpublished notes, has described a supposed occurrence of the formation on the Georgia Railroad, three miles northwest of Norwood. The materials consist of red, pebbly sand and loam, 15 feet in thickness, resting upon deeply decayed, crystalline schist. The pebbles are for the most part subangular quartz up to three or four inches in diameter, with a small percentage well rounded. Cross-bedding was observed at one place. The deposit is believed to be an isolated remnant of Lower Cretaceous strata. Veatch also notes a deposit of coarse sand and angular gravel probably belonging to this formation at Beall Spring, eight miles southwest of Warrenton.
The Lower Cretaceous terrane is present over the greater part of McDuffie County south of the Georgia Railroad, and t):1ere are a few small areas extending north of the railroad. The beds rest upon crystalline basem'lnt rocks. In the southern part of the county the Lower Cretaceous strata are overlain in disconnected areas by Eocene sediments. Streams have cut through the beds at many places, revealing the underlying crystalline rocks.
Materials referable to the formation are noted by Veatch in his ciay report (pp. 200-203, abstracted, not quoted), at the following
places in this county:

One mile east of Thomson on the Shields property a bed of white clay

ten feet thick is reported.

On the Brinkley plantation, three miles southwest of Dearing, 16 feet of white kaolin blotched with purplish or pink iron stain, is reported to have

been penetrated in a well.

Three miles west of Dearing, on the Milledgeville public road, a bed of

plastic, white clay occurs at a point locally known as "Chalk Hill". About

one-half mile west of this locality 30 feet of white clay is reported to have

been penetrated in a well, the top of the clay bed having been encountered

30 feet below the surface.



Exposures of Lower Cretaceous clay are numerous throughout the south-

eastern part of the county along Boggy Gut, Headstall, and Brier Creeks.

Especial note is made of such clays on the T. J. Connell and J. F. Wb.itaker

properties, four and one-half miles south of Harlem.

Veatch also furnishes the following unpublished notes:

"At mile-post 34, near Boneville, the base of the Lower Cretaceous consists of coarse sand containing clay and sub-angular quartz gravel. Fragments of vein quartz as much as two feet long were observed. A biotite

102

GEOLOGY OF THE COASTAL PLAIN

granite is exposed in a small stream one-half mile east of this locality. The Lower Cretaceous strata at Boneville is not more than 40 feet thick, according to a well record.
"On the property of Thomas Jefferson, two and one-half miles southeast of Dearing, eight feet of white and stained clay underlies unconformably 20 or 30 feet of laminated clay, probably of Eocene age."

Lower Cretaceous strata are present in the southern part of Columbia County in limited areas in the vicinity of Harlem, Berzelia, and Grovetown. They rest unconformably upon crystalline basement rocks and are overlain in part by overlapping Eocene strata which in places transgress northward entirely across the Lower Cretaceous beds and rest upon the crystallines.
There are good exposures of arkosic sands and white and purplish clays referable to this formation in cuts one to two miles east of the station at Grovetown. Although the contact does not appear in the railroad cuts, other exposures in the vicinity of Grovetown show the Lower Cretaceous strata to be overlain unconformably by fullers earth clay of Eocene age. This relation is well exhibited in what is known as Phinizy Gully, about one mile east of Grovetown, on the old abandoned Augusta to Wrightsboro wagon road. The following sketch shows the profound character of the unconformity.

W.

E.

~-,{~'=~Tss~::.

k----------...,_:---200'-------~

Fig. 8. Sketch showing relation of Cretaceous and Eocene strata at Phinizy Gully, near Grovetown, Ga.

Explanation of sketch.
Eocene. 3. Shaly fullers earth clay with fine sand partings. Contains leaf impressions and casts of pelecypods . . . . . . . . . . . . . . . . . . . . . (Unconformity.)
Lower Cretaceous.
2. Coarse, gray, argillaceous sandstone . 1. Coarse, arkosic sand . . . . . . . .

Feet.
12 to 15
8 12

The following references to Lower Cretaceous beds in this county

are abstracted (not quoted) from Veatch's clay report, pp. 196-200 :

At the works of the Georgia Vitrified Brick & Clay Company, at Cam

pania, one and one-half miles east of Harlem, 12 feet of white clay is ex-

posed in a pit 100 yards northeast of the plant. As shown by other pits

nearby this clay is overlain by 25 feet or more of clay and sand referable to

the Eocene, (Claiborne).-(See detailed section, p. 271 of this report.)

,

In the old fullers earth pit on the Fiske property at Grovetown, 3 or 4

feet of white clay makes up the base of the section. It is overlain by Eocene

fullers earth.-(See p. 269 of this report.)

LOWER CRETACEOUS

103

At ~hillips Falls, one and one-half miles southwest of Harlem, ten feet of massive gray to bluish gray, hard clay is overlain by about 40 feet of Eocene sands and clays. The clay is underlain by Lower Cretaceous sand containing large chunks of kaolin and disseminated kaolin grains.-(See detailed section on p. 271 of this report.)

In unpublished notes Veatch describes Lower Cretaceous beds at the following additional localities in this county:
"One-half mile west of the section foreman's house at Forest, eight to ten feet of arkose is exposed overlain by Eocene fullers earth.
"Near the 17-mile post, two miles south of Grovetown, four or five feet of white clay presumably of Lower Cretaceous age is superimposed by red and yellow sands probably of Eocene age.
"On the H. Merry place, four and one-half miles southwest of Berzelia, on Sandy Run Creek, ten feet or more of Lower Cretaceous clay and sand was observed beneath 90 feet of Eocene sands and clays.-(See detailed section p. 291 of this report.)
At the lignite pit of the Georgia Lignite Mining Company, three miles south of Grovetown, coarse quartz sand containing white clay was encountered at the bottom of a shaft beneath the lignite. The coarse sands are referred to the Lower Cretaceous, while the overlying lignites are believed to belong to Eocene.-(See detailed section, p. 270 of this report.)
Coastal Plain deposits coYer all o Richmond County except a small area in the extreme north. Lower Cretaceous strata outcrop in a belt several miles wide extending rom Augusta and south o Augusta westward to the county line, and also farther south in the county along the valley o Spirit Creek. The ormation rests unconformably upon crystalline rocks which outcrop in the northern part o the county. The Lower Cretaceous beds pass to the southward beneath overlapping Eocene strata, the latter covering nearly all o the southern part of the county. There is also a long, narrow area o Eocene strata capping the ridge between Butlers and Spirit creeks, and extending northwestward to Grovetown in Columbia County.
The hills to the west an<l southwest o Augusta, with the exception o their surficial deposits o sanely clays, sands, and gravels, are made up o Lmver Cretaceous beds. The materials consist o characteristic, coarse, arkosic, argillaceous sands with subordinate lenses of clay. The strata are or the most part concealed by coarse, surficial gravels and red sands which cover the tops and slopes o the hills. The age o the latter has not been satisact01ily determined, but they may be Eocene. In the cnts o the Georgia Railroad between Augusta and Grovetown there are numerous exposures o coarse, cross-bedded, arkosic sands, containing in places pellets and boulders o white clay and occasional lenses, which are referable to the Lower Cretaceous.
A well, 144 feet deep, located on the property o R. T. Ulm, two miles north o Debruce, is said by the owner to have passed through sand to a depth o 140 feet, below which clay was penetrated to a depth o our feet. The section is probably all referable to the Lower

104

GEOLOGY OF THE COASTAL PLAIJ.,~

Cretaceous, although a small thickness of Eocene strata may compose
the upper portion.
The following data concerning the occurrence of the formation in
this area have been abstracted (not quoted) from Veatch's clay
report, pp. 185-196, and from his unpublished notes:
In the vicinity of Belair a small thickness of Lower Cretaceous strata is present. The beds rest upon the upturned edges of metamorphic schists. The materials consist of gray or white sands containing clay pellets with interbedded, thin, white clay layers.
One and one-quarter miles east of Belair at the eight-mile post, a cut of the Georgia Railroad exhibits the following section:

Section at the eight-mile post, Georgia Railroad, Richmond, County, Ga.

Lower Cretaceous. 3. Strongly crossbedded sand with soft, white clay pebbles one to two inches in diameter, and scat-
tered quartz pebbles . . . . . . . . . . . . (Local unconformity.)
2. White and stained clay . . . . . . . . . . . . 1. Gray and white, unconsolidated, arlwsic sand .

Feet.
7 to 10 0 to 4
4

Total. . . . .

18

On tile Milledgeville road, five and onehalf miles northwest of Augusta, at a place known as "The Rocks" an indurated arkose is exposed. The rock is a gray, arkosic sandstone, resembling decomposed granite, its sedimentary character not being readily recognized. It is composed of angular quartz,
muscovite mica, and kaolin, with small amounts of magnetite and rutile recognizable only under the microscope. Hard, opaline silica is the cement-
ing agent. A thickness of 15 feet was observed.

Section on the east side of a small stream on the King estate, two

and one-half miles south of Belair, and five miles southeast of Grove-

town. (Clay report, p. 192.)

5. Slope covered by a mantle of loose sand . . . . . 4. Red and orangecolored loose ~and . . . . . . . . 3. Semi-indurated, massive bedded, white clay . . .
2. Orange-colored sand, with pebbles and white clay layers . . . . . . . . . . . . . . . .
1. Sand to creek, character concealed . . . . . . . .

Feet. 20 40 18
30 50

Layer No. 4 is referable to the Eocene (Claiborne group), and layers Nos. 1, 2, and 3 to the Lower Cretaceous. A similar section occurs about one-half mile below the preceding.
On the old Blackstone place, one mile south of the 18-mile post on the Georgia Railroad, at a place known as O'Connor Hill, the following section
.occurs:

GEOLOGY OF THJfJ OOASTAL PLAIN OF GEORGI A.

PLA'l'JfJ IX.

A. SLICK BLUFF. CHATTAHOOCHEE RIVER. RIGHT HANK, FOURTEEN MILES BELOW COLUMBUS,

./

GA., SHOWING GREENISH GRAY CLAY

OF THE EUTAW FORMATION.

B. SANDSTONE DIKE IN CLAY OF THE EUTAW FORi\fATION. AT SLICK BLUFF. CHATTAHOOCHEE RIVER, FOUR'l'EEN MILES BELOW COLUMBUS, GA.

LOWER ORETAOEOUS

105

Section on Blackstone place, O'Connor Hill, one mile south of 18 milepost, Georgia Railroad.

Age? 6. Limonite fragments in sand . 5. Siliceous iron ore . . . . . . 4. Gravel bed . . . . . . . . . .
Eocene (Claiborne group.) 3. Fine red and yellow sand with thin clay layers .
(Unconformity.) Lower Cretaceous.
2. Massive white clay . . . . . . . . . . . . . . . ::.. Partly concealed, but consisting in part of white,
micaceous, arkosic sand . . . . . . . . . .

Feet. 10
2 to 4 3
50
12
40

A considerable thickness of hard, white, fire clay occurs along Sandy

Run in the southwestern rart of the county.



At Hephzibah the Lower Cre,taceous is well exhibited in a pit of the

Albion Kaolin Company. The section given below was made along the north

side of the pit, but sections exposed in other parts of the diggings show the

strata to be extremely variable in character horiwntally. (See clay report

pp. 18!:188.)

Section on north side of pit of Albion Kaolin Company, Hephzibah, Ga.

Eocene (Claiborne group). 5. Bright red sand, estimated . . . . . . . . 4. Shaly sandstone containing fossil leaves .
Lower Cretaceous. 3. Semi-indurated, massive, white clay . . . . . . 2. Crossbedded, arkosic, micaceous sand with white clay particles and pellets, locally indurated to sandstone . . . . . . . . . . . . . . . . . . . 1. Soft, white and cream-colored clay, reported thickness .................... .

Feet. 40
4
3 to 20
3 to 20 9

Total about . .

76

Sav.annah River.-No exposures of Lower Cretaceous strata occur in the immediate banks of the river at .Augusta. However, a short distance northeast of the wagon bridge in .Aiken County, S. C., the supposed base of the formation is seen, as described in the following section:

Section a short distance northeast of the wagon bridge leading from Augusta to Old Hamburg, Aiken County, S. C.

Lower Cretaceous. 2. Heavy bed of pebbles and cobbles of quartz and crystalline rock, angular to smoothly-rounded, in a matrix of sandy clay . . . . . . . . . . .
(Unconformity.)
Basement rocks. 1. Decayed schist, about . . . . .

Feet. 4 to 8
20

106

GEOLOGY OF THE COASTAL PLAIN

The base of the section is about 40 feet above zero water level of the river.
The only place where the formation -is exposed in the immediate bluffs of the river is at Sand Bar Ferry, about four miles below Augusta, in Aiken County, S. C.

Section at Sand Bar Ferry, four miles below Augusta, Ga., in Aiken

County, S. C., left bank.

Pleistocene? 4. Yellow, mottled, argillaceous, coarse sand . 3. Medium to coarse, light gray and yellow micaceous, argillaceous sand with gravel lenses developed in the lower 10 feet . . . . . . . . .
(Unconformity.) Lower Cretaceous.
2. Coarse, arkosic, micaceous, argillaceous sand with small, white clay balls . . . . . . . . . . . .
1. Concealed to waters edge . . . . . . . . . . . .

Feet. 6
20
25 10

The point at which the top of the Lower Cretaceous terrane passes beneath water level on the river can not be observed on account of the alluvial deposits through ~vhich the river flows below the last described bluff.

Wells sotdh of the belt of outcrop.-South o the belt of outcrop of the Lower Cretaceous strata several wells have been drilled through the overlying Eocene beds into the Lower Cretaceous beds beneath. Logs of three such wells have been published by Pro. S. W. McCallie and are repeated here.

Log of well at Sandersville, Washington County, Ga., prepared from

samples furnished by C. E. Warthen.

12. White and dark clays with pyrite . . . . . . . .

11. White, sandy limestone . . . . . . . . . . .

10. Gray limestone, with fragments of shells .

9. Dark clay . . . . . .

. .. . .

8. Yellow, coarse sand . .

7. White kaolin . . . . . .

6. Fine white sand . . . .

5. Dark, pyritiferous sand

4. White kaolin . . . .. . . .

3. Rather coarse brownish sand

2. White sand . . . . . . . . . .

1. Fine white sand . . . . . . .

Feet.
. at 35
" 85 " 103 " 160 " 215 " 270 " 285 " 335 " 370 " 387 " 426 " 436

The upper four layers in the above described well at 35, 85, 103, llnd 160 feet, respectively, are believed to belong to the Eocene, and the remainder of the strata to the Lower OrP.t..o.ceous.

1Bull. Geol. Survey of Georgia, No. 15, 1908, p. 186.

LOWER CRETACEOUS

107

Log' of well at Tennille, Washington County, Ga., copied from the



notes of the well contractor.

Feet.

25. Sandy clay . . . . . . . .

0

38

24. White clay . . . . . .

38

52

23. Yellow sandy clay . . . . .

52

80

22. White sand . . . . . . . . . .

. . 80

91

21. Yellowish limestone, in the form of boulders .. 91

96

20. Gray sand . . . . . . . . . .

. 96 103

19. White sand . . . . . . . .

. . . 103 130

18. White sandstone containing shells . . . . . . . 130 140

17. Bluish marl . . . . . . . . . . . . . . . . . . 140 185

16. Yellow clay . . . . . . . . . . . . . . . . . 185 194

15. Brownish colored sand, containing sharks' teeth

and fragments of oyster shells

. 194 210

14. Blue marl'

. 210 260

13. 'Quicksand . .

. 260 270

12. Blue marl . . . . . . .

. 270 300

11. White clay . . . . . .

. 300 310

10. Blue clay . . . . . .

. 310 350

9. Blue and gray sands

. 350 360

8. Blue clay . . . . . . .

. 360 404

7. Quicksand . . . . . . . .

. 404 436

6. White clay and sand

.... 436 440

5. Coarse white sand .

. . . 440 470

4. White "sticky" clay . . . . . .

. . . 470 500

3. Red clay . . . . . . .

. . . 500 530

2. White clay . . . . . . . . . . . . . . . . . . . . 530 550

1. Clay and sand, except at 820 feet, where sand-

stone occurs . . . . . . . . . . . . . . . . . . 550 990

The strata from the surface to a depth of 300 feet in the above described well probably belong to the Eocene; the remainder of the bed;; are believed to be of Lower Cretaceous age.

A portion of the log' of am oil-prospecting well, three and one-half miles southwest of Louisville, Jefferson County, Ga., furnished by the contractor, Mr. James Tague.

46. Sand . . . . . . . 45. Red clay . . . . .
44. Red and white clay 43. Red clay .. 42. Sand . . . . . . 41. White clay . . 40. Hard clay ... . 39. Clay . . . . . . . 38. Sand with gas . . . . . . . 37. Sand with hard layers .... 36. Mixed clay .... 35. Sand 34. Mixed clay .
33. Sand

Feet.
307 505 505 510
510 532 532 562 562 581 581 583 583 584 584 588 588 599 599 661 661 665 665 704 704 741
741 751

10p. cit., pp. 187, 188. op. cit. pp. 128-131. .

108

GEOLOGY OF THE COASTAL PLAIN

32. Clay.

31. Sand

30. Tough clay

29. Sand

28. Hard layer

27. Sand
26. Sandy clay ..

25. Sand

24. Mixed clay

23. Sand

22. Mixed clays

21. Sand

20. Clay

19. White and yellow sand

18. White clay

17. Sand

....

16. Shale
15. Clay ..

14. Sand
13. Clay ..

12. Hard layer

11. Blue clay

10. Sand
9. Clay ..



0

0

8. Sand
7. Shale . .

....

6. Sand

5. Clay.

4. Clay and shale

3. Very hard shale

2. Cemented gravel

1. Hard rock

'



0

751 759
759 775 775 783 783 793
793 798 798 800 .. 800 843 843 853 853 870 . I 870 896 896 913
913 929 929 948
948 955 955 965
. ' 965 976 976 979 979 999 999 1001
. 1001 1006 . 1006 1006
. 1006 1027 . 1027 1035
. 1035 1052 . 1052 \ 1058 . 1058 1062 . 1062 1068 . 1068 1088
. 1088 1111 .1111 1113 . 1113 1140
. 1140 1143

Fossils characteristic of the Claiborne group of the Eocene were cbtained from the preceding well at a depth of 250 feet. A fragment of a turtle plate, supposed to be referable to the Upper Cretaceous, was obtained at a depth of 380 feet. On the basis of these fossils the contact between the Cretaceous and Eocene is believed to be -somewhere between the depths indicated, and it is here placed tentatively at 350 feet. Crystalline basement rocks were encountered at 1,140 feet. The probable total thickness of Cretaceous strata penetlated is, therefore, 790 feet.
The data obtained from this well were insufficient to permit distinguishing between UppBr and Lower Cretaceous strata, but it is believed that beds of both ages are represBnted. Doubtless the lower 500 or 600 feet of the Cretaceous portion of thB section should be referred to the Lower Cretaceous and the remainder to the Upper Cretaceous, probably to the Ripley formation.

CORRELATION
The basal portion of the Cretaceous deposits of the Coastal Plain in the region included between Alabama Valley in Alabama and the

LOWER CRETACEOUS

109

Hoanoke Valley, in North Carolina is composed of highly cross bedded, arkosic sands, in general of coarse texture, with subordinate, inter-bedded layers and lenses of light-colored clays of greater or lesser purity, reaching an estimated maximum thickness of 500 or 600 feet. These have been erroneously regarded as the eastward continuation of the Tuscaloosa formation by the Alabama and Georgia geologist.' ' They have been designated the "Hamburg beds" by Earle Sloan' in South Carolina, and the "Cape Fear" formation by the writer' in North Carolina.
In the Carolinas these beds are separated from the overlying Black Creek formation by an unconformity. Likewise an unconformity separates them from the overlying Eutaw formation in the Chattahoochee and Alabama river regions in Georgia and Alabama.
In 1906 the exposures of these beds on Chattahoochee River below Columbus, Ga., were examined by the writer, and during subsequent years numerous localities in Alabama and Georgia were visited. Various considerations, based upon physical evidence, led to the conclusions that the terrane was older than the Tuscaloosa formation; that it probably corresponded to the "Hamburg beds" of South Carolina, and to the "Cape Fear" formation of North Carolina; and that it was probably of Lower Cretaceous age. Mr. E. W. Berry, who, in company with the writer, later visited a number of the localities, concurred in these views.
The first and strongest argument in favor of this interpretation was the existence of a distinct UJ!Conformity separating the beds in question from the overlying Eutaw formation. This was noted unmistakably at the following places: McBride Ford on Upatoi Creek, Chattahoochee County; at the Lumpkin road bridge over Upatoi Creek a few miles above its mouth; on Chattahoochee River just below the mouth of Upatoi Creek; and at Broken Arrow Bend, nine miles below Columbus, Ga.; on the Seale road, four miles southwest of Columbus in Russell County, Ala., and on Alabama River, five miles above Montgomery, Ala. In addition to these the unconformity was questionably noted at several places intermediate between those mentioned. No such unconformity is knmvn to exist between the true Tuscaloosa formation and the overlying Eutaw formation in central or western Alabama or in Mississippi.
The beds differ from the true Tuscaloosa deposits in the presence

1Langdon, D. W., Variations in Cretaceous and Tertiary Strata of Alabama: Bull.

Geol. Soc. America, vol. 2, 1890, pp. 587-606.

.

2Veatch, Otto. Second report on the clays of Georgia: Geol. Survey of Georgia,

Bull. No. 18, 1909, pp, 82-106.

'Clays of South Carolina: South Carolina Geol. Survey, ser. 4, Bull. No. 1, 1904,

pp. 72-75.

.

some facts relating to the Mesozoic deposits of the Coastal Pla1n of North Caro

Una: Johns Hopkins University Cit,:cular, new series, July, 1907, No. 7 (whole num

ber 199), pp. 93-99.

110

GEOLOGY OF THE COASTAL PLAIN

of a large percentage of white kaolin grains in the sands, rendering them arkosic; in the massive character of the clay lenses, thus contrasting with the laminated beds so common in the Tuscaloosa; and in the absence, except in rare instances, of fossil plant remains in the deposits. On the other hand, the beds strongly resemble the "Hamburg beds" of South Carolina, and the "Cape Fear" formation of North Carolina, and this fact, together with the fact of apparent continuity with the Carolina deposits, led to the belief that they were synchronous with them.
The "Cape Fear" formation is separated geographically from the Cretaceous deposits to the northward in Virginia by an overlap of J\Iiocene beds. However, in all their physical characters they bear a close resemblance to the Patuxent formation which forms the basal division of the Potomac group in Virginia and Maryland. On account of this physical similarity, and because of their supposed buried connection with the Virginia Patuxent, the application of the name Patuxent has been extended to include these North Carolina arkosic beds.1 Were it not for certain biological evidence to the contrary it would seem proper to extend the application of the name still farther to the southward to include the apparently continuous deposits in South Carolina, Georgia, and Alabama. Until recently no organic remains had been found in the beds in question south of the Virginia line. In the fall of 1910, the writer discovered a few poorly preserved plant remains in beds exposed in a bluff of Tallapoosa River at Old Fort Decatur, in Macon County, Ala. These have been submitted to Mr. E. W. Berry, who expresses the opinion that the beds containing them are of Lower Cretaceous age.
The previous conclusions regarding the age of the beds below the Eutaw formation seem thus to be conrmed by the paleontologic evidence. Unfortunately, the poorly preserved condition of the leaves renders it difficult to determine satisfactorily the relation of the formation to the Patuxent formation of Yirgin.ia and Maryland. However, in Mr. Berry's opinion, the presence of large numbers of leaves, apparently dicotyledons, most of \Yhich are too poorly preserved to permit of specic or even of generic determination, seems to justify
doubt as to their being so old as the Patuxent formation, in which
similar questionably identied dicotyledons are very sparingly repre-
sented. The following statement concerning the fossil remains of
the Patuxent formation is quoted from a paper by Prof. Wm. B.
Clark and Mr. Arthur Bibbins :2
lA r~port by the writer on the Cretaceous of North Carolina, now in press as a publication of the North Carolina Geological Survey.
2Geo1. Soc. America, BulL, vol. 13, 1902, p. 192.

UPPER CRETACEOUS

111

"The flora of the Patuxent formation includes equiseta, ferns, cycads, conifers, monocotyledons, and a very few archaic dicotyledons, the coniferous and cycadean element being particularly strong. The known fauna of the Patuxent formation is limited to a single unio (Ward) and a fish (Fontaine)."
Should future discoveries confirm this doubt the question would at once be raised as to the relation of these deposits to the "Cape Fear" formation of North Carolina, to which the use of the name Patuxent has been extended. Should the relation be found to be that of synchroneity the inappropriateness of the name Patuxent for either the Carolina or the Georgia-Alabama deposits would at once be apparent.
It may be stated here that although the "Cape Fear" beds appear to be continuous with the Lower Cretaceous beds of South Carolina, Georgia, and Alabama, it is quite possible that they are not actually continuous; for the irregular character of the bedding, the presence of numerous local unconformities within the beds, and the lack of extensive exposures, render the detection of an important unconformity difficult-and such an unconformity may exist.
An hypothesis suggested to the writer by Dr. T. Wayland Vaughan, which is also worthy of consideration, is that the arkosic beds extending from Maryland southward to Alabama were laid down along a coast margin which was gradually and continually depressed from the north to the south. In this case the deposits might actually be continuous and yet contain fossil plants at the southern end younger than those at the northern.
UPPER CRETACEOUS
EUTAW FORMATION

NAME

The name Eutaw group was proposed by_ Dr. Eugene W. Hilgard'

in 1860, for deposits in Mississippi which he described as: "Bluish

black, or reddish, laminated clays, often lignitic, alternating with,

and usually overlaid by, non-effervescent sand, mostly (though not

always) poor in mica, and of a gray or yellow tint." These con-

stituted the basal portion of the Cretaceous deposits of the State, their

lower limit being the surface of the Paleozoic rocks upon which they

rested and their upper limit the base of the overlying Tombigbee sand

group.



Explaining the use of the term Eutaw he says :2 "I adopt this

name in view of these beds having been first examined and recognized

as being of Cretaceous age by Tuomey, near Eutaw, Alabama, where

they are characteristically developed."

'Report on the geology and agriculture of the State of Mississippi, 1860, pp. 61-68. 20p. cit., p. 61.

112

GEOLOGY OF THE COASTAL PLAIN

Tuomey's account of the beds near Eutaw to which Hilgard re ferred is recorded in the "First Biennial Report of the Geological Survey of Alabama," 1850, pp. 118-120.
Smith and Johnson,' in 1887, in their classification of the Alabama Cretaceous, adopted the name Eutaw, with, however, a modified meaning. According to their definition the base of the "rotten limestone" (Selma chalk) was made the upper limit of the formation, thus including the Alabama equivalents of Hilgard's Tombigbee sand, while below the Eutaw thily differentiated a formation consisting of at least 1,000 feet of "purple and mottled clays interstratified with white, yellowish white, pink, and light purple, micaceous sands, and near the base of the formation dark, gray, nearly black, thinly laminated clay with sand partings," the Mississippi representatives of which Hilgard had included in his Eutaw group. For the latter they introduced the term Tuscaloosa formation.
The classification of Smith and Johnson expresses the difference between a series of irregularly bedded sands and clays of probable estuarine and non-marine origin, or perhaps in part of shallow marine origin, the Tuscaloosa formation, and a series of superjacent sands and clays clearly of marine origin, the Eutaw formation. The basis of this classification is regarded as the more 'logical and for this reason the nomenclature of the Alabama geologists is here used. The Tomhigbee sand of Hilgard which thus becomes a part of the Eutaw formation, is roughly traceable eastward from Mississippi through Alabama, constituting the upper 150 or 200 feet of massive, more or less ealcareous and phosphatic oands of the division, as distinguished from the more irregularly bedded sands and clays forming the lower 200 or 300 feet of the formation. This upper more massive portion was recognized by Smith and Johnson and was spoken of by them as the "upper member of the Eutaw formation." Although this so-called member can not be sharply differentiated from the less massive beds beneath it, it is eminently fitting that the original name applied to it in Mississippi should be perpetuated. It is therefore referred to in this report as the Tombigbee sand member of the Eutaw formation.
The Tuscaloosa formation, it is believed, is not represented in
Georgia. The Eutaw formation is represented in Georgia by the beds which
Langdon referred to the Eutaw group and by about 120 feet of overlying beds which formed the base of his "Ripley group," but which are, on paleontologic grounds, here considered synchronous with the Tombigbee sand member of the Eutaw formation.
'Bull. U. s. Geol. Survey, No. 43, 11S87, pp. 71-VlS.
Bull. Geol. Soc. America, vol. 2. 1891, pp. 587-606.

A. INDURATED LAYER OF FOSSILIFEROUS, MARINE SAND OF THE E UTAW ~'ORMATION , IN BED OF OCHILLEE CREEK, AT OCHILLEE, CHATTAHOOCHEE COUNTY. GA .
B. EXPOSURE I CUT OF COLUMBUS-LUMPKIN HOAD, THIRTEEN MILES SOUTH OF COLUMBUS. GA. , IN CHATTAHOOCHEE COUNTY, SHOWING UNCONSOLIDATED SAND OF THE EU'AW FORMATION.

EUTAW FORMATION

113

DEFINITION

Areal distribution.-The Eutaw formation is exposed in the bluffs

of Chattahoochee River from a point a short distance below the mouth

of Upatoi Creek, nine miles below Columbus, in Chattahoochee

County, Ga., to a point two or three miles below the Seaboard Air



Line Railway bridge at Omaha, in Russell County, Ala. Disregard-

ing the irregularities of the stream's course, the formation has a

north-south width of about 10 miles where it intercepts the river. To

the northeastward away from the river the area becomes narrower,

finally disappearing in Taylor County. It includes parts of Stewart,

Chattahoochee, :Marion, m1d Taylor counties (see map, opp. p. 58.)

The formation outcrops in a be1t having an average \Vi(lth of eight or

ten miles extending from Chattahoochee River westward through Ala-

bama and northward through JI.Iississippi to the vicinity of the

Tennessee State line.

Stratigraphic position.-The formation in Georgia rests unconformably upon beds of Lower Cretaceous age. The unconformity separating the two terranes is of considerable importance, for if the correlations indicated in this report are correct, the time interval represented by this unconformi(y in Georgia must be as long as the time required for the deposition of the Tuscaloosa formation and probably also a part of LmYer Cretaceous time. To the west of Alabama River in Alabama, the umlerlying Lower Cretaceous strata disappear beneath the Tuscaloosa formation, the latter resting directly upon the basement rocks.
The Eutaw formation in Georgia is overlain by the Ripley formation. In limited areas bordering Chattahoochee River and Upatoi Creek the formation is overlain unconformably by thin Pleistocene terrace deposits.

Lithologic characters.-Considerable variation has been noted in the character of the lnaterials of this formation, both vertically and horizontally. In the immediate Chattahoochee region they are in the main of marine origin, though a part of them was obviously laid down in very shallow marine waters, and some may even have originated in estuaries or sounds.
East of the river. in the northeastern part of Chattahoochee County, in. Marion County, and in Taylor County, the formation as a whole becomes much coarser ancl more irregularly bedded, and doubtless originated in shallo\Y water, near shore, or even in sounds and estuaries. Thin beds of well-rounded pebbles ha"Ve been observed in the formation at a few places in Georgia and also west of the river in Alabama. The upper marine portinn nf the formation which in this

114

GEOLOGY OF THE COASTAL PLAIN

report is referred to the Tombigbee sand member of the formation maintains its massive IDarine character to and beyond the Seaboard Air Line Railway northeast of Cusseta in Chattahoochee County. Still farther to the northeast in Marion County this division appears to give way to irregularly bedded sands and clays o shallow water origin.
In the region of Chattahoochee River the immediate base of the formation consists of a few feet of coarse, arkosic, micaceous sands bearing a rather close resemblance to the sands of the underlying Lower Cretaceous beds. Interbedded with these are subordinate lenses of drab to black, laminated, clay, bearing leaf remains in places. Scattered through these sands are considerable quantities of lignite in the form of comminuted particles, twigs, branches, and logs.
Immediately above the preceding occur 50 feet or more of medium to fine, gray to dark gray, more or less micaceous and calcareous sands and clays, indurated in some layers to a nodular, impure limestone. These materials are fossiliferous, and in places contain large numbers of shells and shell prints. The materials and the character of the entombed organisms prove this portion of the formation to be of marine origin.
The bluffs along Euchee Rapids, Chattahoochee River, reveal 40 feet or more of greenish gray, compact, marine clay, which lies closely above the preceding. This is followed by dark, laminated clays with thin, interbedded sand layers, examples of which may be seen in a bluff a short distance above the mouth of Euchee Creek. Coarse and fine sands locally indurated to ferruginous sandstone, all of shallowwater origin, are poorly exposed at Moores, Betons, and Codys rocks, between Euchee Creek and Chimney Bluff. These shallow-water beds are terminated upward by dark, lignitic clays and light to white, unconsolidated sands, which are well exposed at the base of Chimney Bluff. The clays at the latter place contain poorly preserved leaf remains. These beds are overlain conformably by the Tombigbee sand member, a description of which follows:
The irregularly bedded sands and clays just described are succeeded by massive marine beds having an estimated thickness of 120 feet, which were included by Langdon in the basal portion of his Ripley group, and formed a part of the "Blufftown marl" of Veatch. They are here referred, on paleontologic grounds, to the Tombigbee sand member of the Eutaw formation. The materials consist of gray or greenish gray, calcareous, more or less argillaceous sands with some interbedded layers of gray, calcareous, sandy clay. At vertical intervals of several feet the sands are indurated to impure, sandy lime stones and calcareous sandstones, which by their greater resistance to

EUTAW FORMATION

115

erosion form nodular projecting ledges along the faces of the bluffs. (See Pl. VIII.) The materials are more or less glauconitic and calcareous, and iron pyrites is fairly common. Fossil shells occur throughout the beds and certain layers contain them in sufficient abundance to form shell marls. The beds appear along the river in various exposures from Chimney Bluff to a point two miles below Omaha.
Strike, dip, and thickness.-On the Georgia side of Chattahoochee River, the beds of this formation strike approximately northeast and bouthwest. On the Alabama side the strike is nearly due east and west.
It has not been possible to obtain reliable dip measurements of that portion of the formation lying beneath the Tombigbee member of the formation, principally because of the irregularity of the bedding and because the exposures are not sufficiently extensive to show this feature. However, as is true of nearly all Atlantic and Gulf Coastal Plain formations, the amount of dip is relatively small. It is probable that the inclination of the beds is less than the general inclination of the unconformable surface of the underlying Lower Cretaceous deposits upon which the Eutaw formation rests. This unconformable surface, based upon calculations from well data, has an estimated dip of about 48 or 50 feet to the mile. The Tombigbee m-ember of the formation is regularly bedded and exposures are continuous for considerable stretches along the river bluffs. In places indurated layers may be traced for distances of a mile or more. In general these dip down stream, but there are minor undulations and for short distances the dip may even be reversed. On account of these undulations it is not possible to determine the dip with accuracy, but it is believed Langdon's estimate, 20 feet to the mile, approximates the correct amount for the beds of this member in the immediate Chattahoochee region.
That portion of the Chattahoochee section here referred to the Eutaw formation was estimated by Langdon to be 465 feet thick, 345 feet being the figure given for his Eutaw group, which included the beds subjacent to the Tombigbee sand, and 120 feet for the overlying Tombigbee sand. The latter figure is prooably approximately correct, but the former amout-345 feet-is known to be underestimated. A well at a landing on Chattahoochee River, two and one-half or three miles below the mouth of Euchee Creek, in Russell County, Ala., penetrated 362 feet of Eutaw strata before entering the underlying Lower
Cretaceous beds. (See section p. 121 of this report.) Calculations
based on the thickness shown in this well, and the width of outcrop on
the river, give a total thickness of 435 or 440 feet for Langdon's

116

GEOLOGY OF THE COASTAL PLAIN

"Eutaw group," where it passes beneath the overlying Tombigbee sand

member. This would give a total thickness for the formation includ-

ing the Tombigbee sand, of 555 or 560 feet.

'

Little is known of the thickness of the formation to the northeastward in Georgia, but it is believed that it gradually becomes thinner and at the eastern limit of its surface occurrence finally pinches out against the underlying older Cretaceods beds.

Physiog.raphic expression.-The general upland surface of the belt of country in which this formation outcrops is a greatly dissected plain lying 450 to 500 feet above sea level. The weathering and leaching of the sand beds of the formation have produced a surficial covering of loose, gray sand varying in thickness from a few inches to eight or ten feet, which mantles the tops and slopes, giving to much of the country a "sand hill" aspect. In this respect the region resembles that previously described in T.hich the Lower Cretaceous strata come to the surface. The surface relief reaches a maximum of 300 feet. The broken hilly aspect which characterizes the region in general has been modified by Pleistocene terracmg processes in small areas bordering Chattahoochee River.

Paleontologic characters.-Ma:rine invertebrate fossils are numerous in the lower 100 feet of the formation. Near the immediate base these are preserved as shells, shell prints, and internal casts. In beds somewhat higher they appear only as casts and prints. In the next 300 feet or more invertebrate fossils are rare, but a few soft prints of shells have been observed.
In the massive, marine sands anJ clays forming the upper 120 feet of the formation (Tombigbee sand member) invertebrate fossils are plentiful both as shells and as prints and casts.
Vertebrate animals are represented, so far as known, by the remains of sharks only. The teeth of these fishes are present in places in the massive, marine beds near the base, and in the Tombigbee sand member at the top of the formation.
The remains of plants are fairly abundant in certain parts of the terrane. Leaves have been collected at two localities from the nonmarine beds at the immediate base of the division, a;nd also from the irregularly bedded sands and clays forming the base of the section
at Chimney Bluff immediately beneath the beds of the Tombigbee
sand member. Lignite is present at various horizons, as a rule in
the form of small, widely scattered pieces. It is fairly abundant,
however, in the basal leaf-bearing beds, and is very abundant in the

leaf-bearing beds at Chimney Bluff.

EUTAW FORMATION

117

fhe Tombigbee member of the formation forms the lower part of the zone Exogyra ponderosa, of which the lower one-third or onehalf of the Ripley formation forms the upper part.

DETAILED SECTIONS. (PART O.F FORMATION BELOW THE TOMBIGBEE SAND MEMBER.)

Chatta}wochee River.~Exposures of this part of the formation appear in the bluffs of Chattahoochee River at intervals, from a point a short distance below the mouth of Upatoi Creek, nine miles below Columbus, Ga., to Big Bend, 2472 miles below Columbus. The specified localities are indicated in a sketch map of the river, Fig. 6. The exposure below the mouth of Upatoi Creek has already been described and the unconformable relation of the Lower Cretaceous strata to the overlying Eutaw formation indicated. (See section and sketch on p. 83.) The Eutaw materials consist of dark gray, finely arenaceous and micaceous, calcareous clay, with occasional grains of glauconite. The clay contains scattered lime concretions and there are a few imperfect shell impressions and an occasional piece of lignite.
On the right bank at Broken Arrow Bend, 1072 miles below Columbus, there is an exposure, a section of which is given below. (See plate VIII, A.)

Section a! Broken Arrow Bend, Chattahoochee River, right bank.

Pleistocene (terrace deposit). 2. Concealed by vegetation, except along the base, where a band of pebbles appears . (Unconformity.)
Upper Cretaceous.
Eutaw formation. 1. Dark gray, calcareous, micaceous, finely arenaceous clay, with layers of lime concretions in nodular form, one to two and one-half feet apart in upper eight feet. Fossiliferous . . . . . . . .

Feet. 10
13

At this point the Lower Cretaceous strata do not appear above water level. Fossils were collected and the following determined:

118

GEOLOGY OF THE COASTAL PLAIN

Chattahoochee River, Broken Arrow Bend, Alabama side, 10% miles below Columbus, Ga., in Russell County. T. W. Stanton and L. W. Stephenson, collectors.

Locality Numbers.

T.w.s.jL. w.s.\ L.w.s.

847 5384

6409

Mollusca:

Perna sp. nov. . . . . . . . . . .

X

Ostrea cretacea Morton . . . . .

X

Exogyra upatoiensis Stephenson ..

X

Pecten sp. . . . . . . . . . . . . . . . . . .

I X

X

X

X

X IX

X

Anomia sp. nov.. (Same as sp. nov. from Snow

Hill, N. C.) . . . . . .

X

X

Cardium sp. . . . . . . . . .

X

X

Cyprimeria sp. . . . . . . . . .

X

X

Baroda sp. nov. . . . . . . . .

X

X

X

Corbula carolinensis Conrad ..

X

X

Pelecypod casts, undetermined ..

X

TurriteUa sp. . . . . . . . . . . . . . . . . .

X

Placenticeras sp. (cf. P. guadalupae Roemer) . Gastropods casts, undetermined

I X

X

X

Vertebrata:

Lamna texana Roemer . . . .

X

X

Otodus appendiculatus Agassiz

X \

A short distance below the preceding on the opposite side of the river, a good exposure occurs for several hundred yards along the base of a bluff 140 or 150 feet high. The Lower Cretaceous beds appear. here for the last time, as one descends the river, being overlain unconformably by the beds of the Eutaw formation. The details of the section are as follows :

Section at Broken Arrow Bend, Chattahoochee River, left bank, 10% miles below Columbus, Ga.

Upper 110 or 120 feet of slope concealed by vegetation.

Upper Cretaceous.

Feet.

Eutaw formation. 3. Slightly laminated, gray, calcareous, micaceous, sand

with impure lime nodules in layers two to three

feet apart. Contains same fauna as the preceding

locality . . . . . . . . . . . . . . . . . . . . .

15

2. Coarse, crossbedded sand, and laminated clay, in part

reworked from underlying Lower Cretaceous beds containing piece!! of petrified wood, large logs and

smaller pieces of lignite; fossil leaves were found

in a lens of black clay eight inches thick, several
feet above water level. The sand is gray or stained with iron and the clay is gray to black. These

materials grade up conformably into the overlying materials . . . . . . . . . . . . . . . . . . . 2 to 13

EUTAW FORMATION

119

Lower Cretaceous.

(Unconformity.)

1. Characteristic gray sands and clays . . . . . . . . 0 to 5

E. W. Berry' furnishes the following list of plant species collected from Layer No. 2 in the above section:

Malapoenna horrellensis Berry Phragmites pratti Berry
Salix eutawensis Berry Salix flexuosa Newb.
Sequoia reichenbachi (Gein.) Heer

Down the river from the preceding locality the layers of concretions in the Eutaw formation dip gently southward, and at one-half mile below Broken Arrow Bend reach water level. At this point the following fossils were collected :

Locality No. 5386.-0ne-half mile below Broken Arrow Bend, 10
miles below Columbus, Ga.
Mollusca: Perna sp. nov. Ostrea cretacea Mort? (cf. sp. nov. from 'House Bluff, Alabama River.) Exogyra upatoiensis Stephenson Anomia sp. nov. (same as sp. nov. from Snow Hill, N. C.)
Vertebrata: Otodus appendiculatus Agassiz?
Before reaching Euchee Rapids, the upper end of which is about 13 miles below Columbus, the layers of lime nodules have passed beneath water level and, as shown by dredgings, they form the bed of the river at the upper end of the rapids and are the cause of the shoal water at that point.
A number of interesting exposures occur along the course of Euchee Rapids, on the right bank. Burdock Landing is one-half to threequarters of a mile below the upper end of the rapids. The section exposed near the landing is as follows:

Section near Burdock Landing, Euchee Rapids, Chattahoochee River, right bank.

Pleistocene (terrace deposit)

Feet.

2. Yellowish sandy clay with band of gravel at base . 10 to 12

(Unconformity.)

Upper Cretaceous.

Eutaw formation.

1. Greenish, somewhat laminated clay with fine sand

partings, about . . . . . . . . . . . . . . . . . 12 to 3()

A short distance below the landing the follovving fossils were collected near the base of the bluff in Eutaw matmials:

'Contributions to tbe ~Iesozoic flora of the Atlantic Coastal Plain, VI, Georgia~ Bull. Torrey Botun. Club, ::\o. 37, 1910, pp. 504.

120

G0L0GY OF THE COAST.ciL PLAIN

Chattahoochee River, Burdock Larwiing, 13 or 14 miles below Columbv:', Ga. T. W. Stanton and L. W. Stephenson, collectors. (All casts tn clay.)

Locality Numbers

S.l S. T.W L. W.

848

5386

I Mollus~:~a? . . . . . . . . . . . . . . . . . . . . . .

X

Breviarca sp. . . . . . . . . . . . . . . . . . . . : X
Perna sp. nov. . . . . . . . . . . . . . . . . . . . . I X

Ostrea cretacea Morton? (cf sp. nov. from House Bluff, 1

Alabama River) ................. I

X

Ostrea ~1'. nov. ? (aff. 0. lugubris Conrad) . . . . . . 1 X

Pecten sp. nov. (same as sp. nov. from Snow Hill, 1

N.C.) . . . . . . . . . . . . .

. ..... I

X

Anomia sp. nov. (same as sp. nov. from Snow Hill, 1

N.C.). . . . . . . . .

. I

X

Lucina sp. . . . .. . . . . . .

.I X

Cardium sp. . . . . . . . . .

.1 X

X

Cyprimeria depressa Conrad .

.1 X

X

Baroda sp. nov. . . . . . . . Cymbophora lintea (Conrad)

.I X

X

. I

X

Corbula carolinensis Conrad .

.I X

X

Undetermined gastropod casts

.1 X

X

Slick Bluff begins about one-half mile below Burdock Landing and extends interruptedly for some distance along the right bank. (See plate IX, A.) The mass of the materials consist of greenish gray, compact clay, laminated in places. Ac some time in their history the clays have become fractured and the crevices thus formed nlled with sand. The sand has become indurated and now appears as nne, white to light gray sandstone, forming dike-like masses in the clay. (See plate IX, B.) These have been described at some length and illustrated by Prof. S. W. ~IcCallie.1 Occasional casts of fossils are seen in the sandstone. 'The Eutaw clays appear to have been disturbed again in comparatinly recent times, perhaps at some time during the Pleistocene or men the Recent epoch. This disturbance is evidenced by. the 'fact that the bedding plains in the clay vary as much as 15 or 20 ,degrees from the horizontal, appearing at diverse angles at the different exposures alon?: the bluff, and at several places poorly exposed fault plains "ere obserwd. In the >Yoods back from the bluff for about. one hundred yar<h, the snrface presents sharpcrested ridges running parallel with the river bank, and in places the depressions between the ridges are undrained and hold stagnant pools of water. Some of the older and larger trees stand out of plumb. This topography is believed to have been produced by a series of land

lAm.Geol., vol. 32, October, 1903, pp. 199202.

GlilOLOGY OF TH E COASTAL PL.lTN OF GEORGIA.

PLATE XI.

A. BLUFF BELOW BA KS LANDING, CHATTAHOOCHEE RIVER, TWENTY-SIX AND ONE-HALF MILES BELOW COLUMBUS, GA., LEFT BANK, SHOW! G GRAY, CALCAREOUS SAND AND SANDY CLAY. WITH INDURATED LAYERS, BELONGING TO THE TOMBIGBEE A D 1\IEMBER OF THE EUTAW FORMATION.
B. BLUFF AT SNAKE SHOALS, CH A~'TAHOOCHEE RIVER, THIRTY MILES BELOW COLUMBUS. GA. , RiuHT BA K. SHOWI '0 GRAY, CALCAREOU SA DS WITH ONE INDURATED LAYER. BELONG! G TO THE TOMBIGBEE SAND MEMBER OF THE EUTAW FORMATION, OVERLAIN BY PLEISTOCENE DEPOSITS.

EUTAW FORMATION

121

slides, the land slipping in sections, and at the same time becoming tilted. Several large masses of earth appear in the river as small islands, being apparently the remnants of masses which have slipped into the river at some time in the past.
In a chunk of clay, not in place, the following fossils in the form of casts were collected :

Chattahoochee River, Euchee Rapids, Slick Bluff, about 1-P/2 miles below Columbus, Ga., right bank.

Mollusca:
Nucula sp. Breviarca sp. Ostrea sp. nov.? (aff. 0. lugubris
Conrad.) Cardium sp.

Cyprimeria depress:t Conrad Baroda sp. nov.
Corbula carolinensis Conrad Undetermined pelecypod casts Undet~rmined gastropod casts

About 200 yards above the mouth of Euchee Creek the following section is exposed:

Section about 200 yards above mouth of Euchee Creek, Chattahoochee River, right bank.

Pleistocene (terrace deposit) 2. Sandy clay, grading down into sand, with a band of gravel along base . . . . . . . . . . . . . . (Unconformity.)
Upper Cretaceous. Eutaw formation. 1. Dark gray lammated clay with seams and thin laYers of white sand stained yellow in places with sulphur, and seams of finely comminuted lignitic matter . . . . . . . . . . . . . . .

Feet. 10
25

At Moores Rocks, 18 miles below Columbus, left bank, there are masses of coarse, ferruginous sandstone containing poorly preserved
pelecypod casts in places. At Betons Rocks, 19 miles below Columbus, masses of very coai:se,
in places pebbly, ferruginous sandstone appear in the bed and banks
of the river. A mass similar to the preceding appears at Codys Rock, 20:14 miles
below Columbus. At a landing two and one-half or three miles below the mouth of
Euchee Creek, right bank, in Russell County, Alabama, there is a flowing artesian well. This well has been described by Prof. Eugene A. Smith1 as follows:
"W. J. McLendon's well, near Chattahoochee River; depth, 465 feet. Record: Sand and clay, 20 feet; marl with shell, 65 feet; beds of sand and

1The Underground Water Resources of Alabama. Geol. Surv. of Alabama, Monti:"Omery, 1907, p. 234.

122

GEOLOGY OF THE COASTAL PLAIN

marl, 15 to 25 feet thick, alternating, to 380 feet; hard rock, 2 feet; sand to 445 feet. Water at this point flowed 12 gallons per minute, but has decreased to four gallons. Well lowered 20 feet into sand to hard rock."
This well is located on the lowest Pleistocene terrace bordering the river. The mouth of the well is about 40 feet above zero water level. The first 20 feet of materials penetrated are Pleistocene terrace deposits; the materials from 20 to 382 feet probably belong to the Eutaw formation; and those from 382 to 465 feet probably belong to the Lower Cretaceous. This well, therefore, penetrates 362 feet of Eutaw beds at this point.
The next prominent exposure of Eutaw strata is at Chimney Bluff, 22 miles below Columbus. The section exhibited here at the time visited is as follows:

Section at Chimney Bluff, Chattahoochee River, left bank, about 100 yards up stream from the high, prominent part of the bluff.

Upper Cretaceous. Eutaw formation.
(Tombigbee sand member). 4. Greenish yellow, finely arenaceous, weathered,
marine clay . . . . . . . . . . . . . . . . . . 3. Dark gray, massive, argillaceous, fine, marine
sand, showing some sulphur stain on surface. In this was recognized casts of Inoceramus sp., Orassatellites sp., and Oyprimeria depressa Conrad . . . . . . . . . . . . . . . . . . . . . .
(Part of formation below the Tombigbee sand mem
ber.) 2. Fine, light gray to almost white, loose, finely
cross-bedded, micaceous sand, with occasional
uay films . . . . . . . . . . . . . . . . . . . 1. More or less irregularly bedded, dark, laminated,
lignite clay and loose, micaceous sand. In
places there are lenses of extremely black
micaceous sand, and at other places lenses of slate-colored, extremely micaceous sand. Lignite is present in great abundance in all forms,
from comminuted particles up to large logs. Poorly preserved fossil leaves, representing sev
era! species are present in abundance in some
of the clay lenses . . . . . . . . . . . . . . .

Feet. 6
12 15
20

Layers Nos. 3 and 4 of the preceding section are referred to the
Tombigbee member of the Eutaw formation. Down stream towards the high part of the bluff the white sand
layer described in the preceding section becomes obscured by landslide material and vegetation, and in the high bluff proper it appears to be represented by lenses of greenish gray, sandy clay and subordinate lenses of dark to black clay. Above the clay in this high part of the bluff are 40 to 50 feet of yellowish, sandy, marine clay apparently

EUTA.W FORMATION

123

weathered from darker marine materials which belong to the Tombigbee member of the formation.
E. W. Berry1 has recognized from layer No. 1 of the above section the plant species listed below:
Araucaria bladenensis Berry. Araucaria bladenensis Berry Ficus crassipes Heer Ficus Krausiana (Authority ?) Salix fiexuosa Newb. Salix Lesquereuxii Berry Sequoia Reichenbachi (Gein.) Heer
On the left bank at the Racepasses, about 23% miles below Columbus, the following section is exposed:

Section at the Racepasses, Chattahoochee River, left bank, about 24 miles below Columbus.

Upper Cretaceous.
Eutaw formation. (Tombigbee sand member.)
2. Dark greenish gray, compact, sandy clay, contain ing casts of pelecypods, Pecten burlingtonensis Gabb recognized . . . . . . . . . . . . . . . .
(Part of formation below the Tombigbee sand mem ber.)
1. Laminated, crossbedded, lignitic sands and clays
similar to lower 20 feet of the section of Chim
ney Bluff . . . . . . . . . . . . . . . . . . .

Feet. 14 12

At Big Bend, 241/2 miles below Columbus, .Ga., right 'bank, Eutaw strata consisting o:! irregularly bedded, dark to black, laminated clays and white, crossbedded sands make up the lower 12 to 15 feet of the bluff. These are overlain conformably by several feet of gray, marine sands with fossils referable to the Tombigbee member of the formation. (See list of fossils, p. 108 of this report.) Pleistocene terrace materials make up the upper part of the bluff above the fossiliferous, gray sands.

Region between Chattahoochee and Flint rivers.-Good exposures of that part of the formation beneath the Tombigbee sand member occur to the east of Chattahoochee River in Muscogee and Chattahoochee counties. In the former county the formation is present in an area several miles in width, running east and west in the southern part of Muscogee County, where it forms the upper 100 to 140 feet of strata in the hills lying to the north of Upatoi Creek.
The best exposure of the formation observed in the county is on the Cusseta Road, wh\::re it passes up the scarp from the first or lowest

lContrlbutions to the Mesozoic flora of the Atlantic Coastal Plain-VI, Georgia! Bull, Torrey Botan. Club No. 37, 1910, pp. 604-505.

124

GEOLOGY OF THE COASTAL PLAIN

Pleistocene terrace plain, one and one-half miles southeast o Bull Creek, to the top of the upland one-half mile farther to the southeast. (See topographic map of Columbus Quadrangle.) The section exposed along this road for a distance of about one-half mile is as follows:

:5ection along Cusseta Road, one and one-half to two miles southeast of Bull Creek, Columbus Quadrangle, Ga.

Upper Cretaceous. Eutaw formation? 11. Red, stratified, argillaceous sand . . . . . . . . 10. Interstratified red sand and light, harsh clay layers with a line of pebbles and cobbles along
base . . . . . . . . . . . . . . . . . . . . . . Eutaw formation.
9. Fihe, light, argillaceous sand (weathered) . . . . 8. Laminated, fine sand and clay with iron crusts,
mostly brown in color, due to weathering . . . 7. Mottled, marine sand and clay (weathered) . . . 6. Greenish, drab, fineiy arenaceous, marine clay . . 5. Fine, white, marine sand more or less streaked
with red and yellow due to weathering . . . . 4. Mottled, argillaceous, marine sand, (much weath-
ered) . . . . . . . . . : . . . . . . . . . 3. Greenish gray, argillaceous, marine sand . . . . 2. Coarse, crossbedded sand with kaolin grains and
irregularly distributed clay balls .' . . . . . . (Unconformity, somewhat obscured by weather-
ing.)
Lower Cretacequs. 1. Medium coarse, crossbedded sand, arkosic in part

Feet. 10
8 6 7 10 10 10 17 27 15
20

Another interesting. exposure of the formation in.which its relations to the underlying Lower Cretaceous division is exhibited occurs on the Steam Mill Road, seven miles a little south of east of Columbus. This road is the first road south of the Buena Vista road. (See Columbus Quadrangle.)

Section, Steam Mill Road, seven miles a little south of east of Columbus, on westward facing slope of Tiger Creek Valley.

Upper Cretaceous.

Feet. In.

Eutaw formation.

5. Dark red, weathered, finely arenaceous clay with

numerous plate-like iron concretions . ,. . . . 4

4. Light greenish gray, fine, compact, micaceous,

somewhat argillaceous t:and containing fossil

prints, with numerous, irregular, proportion-

ately short and thick lenses, or segregations of

compact, white, slightly micaceous sand, the lat-

ter partially surrounded on their under surfaces

with layers or films of dark, drab clay. Shell

prints occur rarely in the white sand lenses,

. . . . . . . . . . . . . . . . . . . . about

10

EUTAW FORMATION

125

3. Band of fine, dark, greenish gray, micaceous

sand, pyritiferous in places, not sharply separ-

ated from layers above and below, filled with

soft prints of shells . . . . . . . . . . . about 2 6

2. Band of coarse and fine sand lenses, with poorly

preserved shell prints . . . . . . . . . . about 2

6

(Unconformity, rendered somewhat obscure by

weathering, but apparently marked by an ir-

regular line of iron crusts.)

Lower Cretaceous.

1. Irregularly bedded, light gray, coarse arkosic

sand, with subordinate lenses of light, massive

clay more or less sandy . . . . . . . . . about 80

The white sand masses in layer No. 4 of the above section are not

mechanically includPd chunks, as mig~t at first be suspected from

the conglomeratic appearance of the bed and from its close proximity

to the base of the formation, neither are they of concretionary origin.

Apparently the white sand has been segregated by a sorting process

of some kind while deposition was in progress. (See plate B, oppo-

site p. 96.)



The forms listed below were collected from the fossiliferous layers

of the foregoing section, principally from layer No. 3.

Locality No. 6410.-Steam Mill Road, seven miles a little south of east of Columbus, Ga., uestward-facing slope of Tiger Creek Valley. L. W. Stephenson, collector.
Mollusca: Nucula sp. Perna sp. nov. (probably same as at Broken Arrow Bend.) Cari:Tium sp. Cymbophora lintea (Conrad). Corbula carolinensis Conrad. Anchura sp.

On this same road about one and one-half miles farther to east, weathered marine Eutaw materials were seen on the top of the divide between Steam Mill and \Yolf Creek.
In Chattahoochee County strata belonging to this part of the Eutaw formation have produced the surface materials in a belt four to eight miles wide south of Upatoi Creek, embracing about onP-half of the total area of the county, excepting, hmYever, limited areas along Chattahoochee River and Upatoi Creek where the Eutaw beds are covered by relatively thin Pleistocene terrace deposits. The basal beds have been examined at three localities on Upatoi Creek. - Just above the bridge of the Columbus-Lumpkin road, seven and one-half miles south of Columbus, 10 feet of characteristic light gray, compact sands and clays of the Lower Cretaceous occur beneath several feet of dark, calcareous, marine sands and clays of the Eutaw formation. The extent of the exposure is small, but the contact between the two formations, where observed, is sharp and somewhat irregular, and is believed to represent an important timP intPrrf11

126

GEOLOGY OF THE COASTAL PLAIN

The details of another important section on Upatoi Creek below the Columbus-Cusseta road bridge is given in the following section:

Section on Upatoi Creek one-quarter mile below the bridge of the Columbus-Cusseta road, seven miles southeast of Columbus, Ga.

Upper Cretacoous.

Eutaw formation.

Feet. In.

9. Brown, unconsolidated sand (weathered marine

sand) . . . . . . . . . . . . . . . . .

5

8. Greenish, partially weathered irregularly foliated

fine sand and clay . . . . . . . . . . .

5

7. Fine-grained white sandstone . . . . . .

1

6. Greenish, irregularly foliated, fine sand and clay 2

5. Dark greenish gray, argillaceous sand . . . . . 5

4. Fine-grained, white sandstone . . . . . . . . . . 1 6

3. Very fine-grained, dark greenish gray, argilla

ceous clay with fine, irregular, dark clay folia

tions. Contains discontinuous, nodular lime

stone layers and irregularly distributed lime

concretions. Scattered fragments of lignite pres-

ent in the materials. Fossiliferous . . . . . . 25

(Unconformity, contact not well exposed.)

Lower Cretaceous.

2. Light gray, coarse, crossbedded, more or less ar-

kosic sand, partially streaked with yellow, with

subordinate, sandy clay layers . . . . . . . . 22

1. Concealed to water level . . . . . . . . . . . . . 30

The forms listed below were collected from the fossiliferous layer in the preceding section :

Bluff of Upatoi Creek, seven miles southeast of Columbus, Ga., below the Cusseta Road bridge. Otto Veatch and L. W. Stephenson, collectors.

Leda sp. nov. ? . . . . Cucullaea ? . . . . . . Perna sp. nov. . . . . .
Ostrea cretacea Morton Exogyra upatoiensis sp. nov. . . Pholadomya sp. nov. . . . . Cardium sp. . . . . . . . . Baroda sp. nov. . . . . . . Corbula carolinensis Conrad Undetermined pelecypods . . . Turritella sp. . . . . . . . . Anchura sp. . . . . . . . . . Undetermined gastropods . . .
Vertebrata: Lamna texana Roemer .. Corax falcatus Agassiz Otodus ? ....... .

Locality Numbers

o.v.\ L.W.S.

5373

5377

:I

X X

.I X

X

:I X

X

X

X

. I

X

I

X

:I

X X

X

X

X

X

X
:I ~

' EUTAW FORMATION

127

The third locality mentioned is on Upatoi Creek near McBride Ford, 11 miles (air-line distance) south of east of Columbus, Ga. The exposure is on the south bank of the creek a short distance above the ford. The details of the sections are described on page 86 of this report. The relations of the three formations appearing in the bluff are illustrated in the following sketch:

E.

w.

Fig. 9. Sketch showing the relations of Lower Cretaceous beds 'and the Eutaw formation to each other and to overlying Pleistocene terrace deposits.
Explanation of sketch. 3. Pleistocene terrace deposit.-Principally loose sand with a gravel
band along base. 2. Eutaw formation.-Irregularly bedded, coarse, arkosic, crossbedded
sand with subordinate, chocolate to black clay lenses. The sand is in places full of small, angular, quartz pebbles and some feldspar fragments, the basal portions being especially coarse. The materials contain considerable lignite, some of which is in the form of fairly large logs. The clay lenses contain leaf impressions, for the most part imperfect. However, from one dark lens, six to ten inches thick, near the lower end of the bluff, a number of well preserved leaves were collected. 1. Lower Cretac.eous.-Characteristic, light gray, compact, arkosic sand and drab clay, breaking with hackley fracture.
The Pleistocene terrace bordering the creek on the south side at McBride Ford is only a few rods wide. The hills immediately to the south rise 240 feet above the creek bed. The strata making up the body of these hills belongs to the Eutaw formation, but no good exposures were seen in this immediate vicinity.
The contact between the Lower Cretaceous beds and the Eutaw formation at the McBride Ford locality is undulating and is suf:fic~iently sharp to be easily traceable along the bluff. Although the materials above and below the contact do not differ markedly, the fnrmer having been derived largely from the latter, yet there is a recognizable physical difference. The beds below are more compact, a:re free from lignite, and the clays are non-laminated, breaking with a hackley fracture. The materials above are less compact, show g::oeater signs of current activity during depQsition, contain considerable lignite, and the clays are laminated.

128

GEOLOGY 0:? THE COASTAL PLAl}v

E. W. Berry' has identified :from this locality the plant speCies li2ted below:

Andromeda cretacea Lesq. ? Andromeda wardiana Lesq. Androvettia elegans Berry Aralia eutawensis Berry Brachyphyllum macrocarpum Newb. Cinnamomum heerii Lesq. Cinnamomum Newberryi Berry Eucalyptus angusta Velen. Ficus ovatifolia Berry Manihotoides georgiana Berry

Juglans arctica Heer ? Magnolia boulayana Heer Magnolia capellinii Heer Menispermites variabilis Berry Paliurus upatoiensis, Berry Salix flexuosa Newb. Sequota Reichenbach! (Gein.) Heer Tumion carolinianum Berry ? Zizyphus laurifolius Berry

Several other exposures of the :formation have been studied in the cvunty. At Ochillee there is exposed in the bed of Ochillee Creek about 16 feet of Eutaw materials, consisting of layers of impure limestone interstratified with layers of marine sand. (See plate X, A.) Fossils partially in the form of casts are abundant. The horizon is probably slightly higher than the :fossiliferous layer, No. 3, described in the section on Upatoi Creek below Columbus-Cusseta road bridge. Veatch has published the following more complete section of the strata exposed at and near Ochillee. (Clay report, p. 91.)

Ochillee Creek, Section at Ochillee.
5. Brown or yellow, unconsolidated sand (at top) 4. Blue or black, laminated, sandy clay, "marl" 3. Sandstone . . . . . . . . . . . . . . . . . . 2. Dark gray calcareous sandstone. In places the bed
is composed almost entirely of shells . . . . . 1. Black and gray micaceous, calcareous sand; con-
tains poorly preserved shells and lignite . . .

Feet.
40 4
4
8

Layer No. 4 of Yeatch's section probably corresponds to the thick clay bed exposed at Slick Bluff, and other bluffs along Euchee Rapids, Chattahoochee River.
The following fossils ha'Ve been recognized at the Ochillee locality:
'Contributions to the Mesozoic flora of the Atlantic Coastdl Plain~ YT <:;P~r!!ia : Bull. Torrey Botan. ,Club No. 37, 1910, p. 504.

..L,, "
I' .

GEOLOGY Olt' 1'HE COA STAL PLA IN OF GEORGIA

PLATE XII

.\ . BLUFF AT BLUFFTOWN, GA., THIRTY-ONE AND ONE-QUARTER MILES BELOW COLUMBUS, GA.. SHOWING GRAY. CALCAREOUS SANDS AND CLAYS. WITH INDURATED CALCAREOUS LAYERS BELONG JNG TO THE TOMBIGBEE SAND MEMBER OF THE EUTAW FORMATION.

B. EXPOSURE IN CUT OF SEABOARD AIR LINE RAILWAY, TWO AND ONE-HALF MILES NORTHWEST OF CUSSETA, CHATTAHOOCHEE COUNTY, GA., SHOWING GRAY, MAR1NE SANDS WITH A LAYER OF CALCAREOUS CONCRETIONS NEAR THE BASE. BELONGING TO THE TOMBIGBEE SAND MEMBER OF THE EUTAW FORMATION.

EUTAW FORMATION

129

Bed of Ochillee Creek at Ochillee) Chattahoochee County) Ga. Ott'o Veatch and L. W. Stephenson) collectors.

Locality Numbers

I o.v. L.W.S.

5374

5378

Vermes: Serpula sp.

.I X I x?

Mollusca: Nucula percrassa Conrad
Cucullaea sp.

I I I X
X I x?

.. Trigonoarca sp. .
Breviarca ?

I X

X

X

Glycymeris sp.

Perna sp. nov.

Ostrea cretacea Morton

Pecten sp..

.

X

I I

X
x?

. .

I . X

x?
X

Anomia sp. nov. (same .as sp. nov. from Snow Hill, N. C.)
.. Etea carolinensis Conrad
Crassatellites ?
Cardium sp.

I

X I x?

X I x?

X

I I

X
x?

Cyprimeria depressa Conrad ?

I X

Baroda ? .

I X

Leptosolen biplicata Conrad Cymbophora lintea (Conrad)

X

I I

X
x?

Corbula carolinensis Conrad

X IX

Undetermined pelecypods
Turi-itella sp. .. Anchura sp. ..

X IX

X I x?

I

X I x?

About three-quarters of a mile southeast of Ochillee on the Seaboard Air Line Railway, a shallow cut reveals at its base two feet of
dark to black, finely micaceous marine clay, containing fossil casts, among which the following were recognized:
Nucula percrassa Conrad Leda sp. Inoceramus sp. Cardium sp. Legumen planulatum (Conrad) Corbula carolinensis Conrad
This clay probably corresponds in stratigraphic position to the base of the clay bed at the Euchee Rapids exposures above mentioned.
At Sulphur Springs on the Seaboard Air Line Railway, 13ljz miles southeast of Columbus, there are poor exposures of coarse, yellow f'andstone. A cut on the same railroad one-hal mile farther to the southeast, reveals 15 feet of medium to coarse-grained, crossbedded sand 'vith occasional thin, light drab clay layers irregularly inter.stratified. These two last occurrences prohabl:v conespond strati-
graphically to the coarse, ferruginous rocks nn Chattahno('hee River
from 20 to 22 miles below Columbus.

130

GEOLOGY OF THE COASTAL PLAIN

At 14% miles southeast of Columbus a cut of the Seaboard Air Line Railway shows several feet of irregularly bedded, thinly laminated dark and light micaceous clay with lenses of fine to coarse sand. Stratigraphically, these materials probably correspond approximately to the irregularly bedded sands and clays making up the lower 20 feet of the section at Chimney Bluff on Chattahoochee River.
In a well on the property of J. R. Christian, four miles west of Ochi1lee, water was secured in soft, white sand at a depth of 60 feet below the surface. This sand is probably referable to the Eutaw formation. The owner is authority for the lithology.
The log of a 'Well on the property of A. K. Cook, two miles east of Shack, Ga., is given below; the owner is authority for the lithology.

Log of well on property of A. K. Coole, two miles east of Shack, Ga.

Upper Cretaceous

Feet.

Eutaw formation.

6. Sand

. . . . . . . . . . . . . . . .

0 to 3

5. Clay

. . . . . . . . . . . . . . . .

3 " 21

4. Sand rocks and coarse sand . . . . . . .

21 " 41

3. Fine white sand, almost as fine as flour, and as

white as snow . . . . . . . . . . . . . . . . . 41 " 47

2. Coarse gravel . . . . . . . . . . . . . . about . 47 " 100

1. Coarse red sand, almost as red as blood . . about . 100 " 104

On the Columbus-Lumpkin road, 11 miles south of Columbus, the southward-facing slope of Gilbert Creek Valley presents the following section:

Section Columbus-Lumpkin road, 11 miles south of Columbus, Ga., southward-facing slope of Gilbert Creek Valley.

Pleistocene (second terrace above the river). 6. Loose, gray surface sands . . . . . . . . . . . . 5. Mottled pink and yellow, micaceous, argillaceous sand . . . . . . . . . . . . . . . . . . . . 4. Gravel bed with coarse, arkosic sand matrix . (Unconformity.)
Upper Cretaceous. Eutaw formation. 3. Laminated, drab clay and fine, yellow micaceous sand . . . . . . . . . . . . . . . . . . . . . . 2. Mottled gray, red, and yellow, coarse to fine sand 1. Drab, laminated clay with seams of comminuted plant remains . . . . . . . . . . . . . . . . .

Feet. 3 10
13
6 18
2

On the same road 13 miles south of Columbus the northward-facing slope of Oswichee Creek Valley furnishes the following section:

EUTAW FORMATION

131

Section Columbus-Lumpkin road, northward-facing slope of Oswichee

Creek Valley, 13 miles south of Columbus, Ga.



Upper Cretaceous.
Eutaw formation. 3. Compact, red, ferruginous, faintly stratified sand 2. Laminated, drab clay and yellow and red, fine to coarse, micaceous sand with some conspicuous lenses of more compact, laminated clay . . . . 1. Fine to medium coarse, loose, light gray to yellowish sand with scattered clay laminae throughour . . . . . . . . . . . . _ ...... _ . .

Feet. 15
12
50

Detailed information concerning the extension of the formation to ' the northeast\vard in Marion and Taylor counties is lacking. However, the beds are known to become coarser and more irregularly bedded, and probably represent near-shore and estuarine phases of the formation. The Tombigbee sand member, described in later pages, which makes up the upper part of the formation, probably also merges to the northeastward into similar shallow-water beds. These resemble so closely the sands and clays of the overlying Cusseta sand member of the Ripley formation that it is not possible to differentiate them without a considerable amount of very detailed work.
A "black marly clay," which probably represents the northeastward extension of the formation, was encountered at depths of 60 to 73 feet in a well one and one-half miles north of Mauk, on the property
0f J. L. Whitley, who is authority for the statement.

DETAILED SECTIONS. ( TOMB!GBEE SAND MEMBER.)
Chattahoochee River.-The Tombigbee sand member appears in the bluffs of Chattahoochee River from Chimney Bluff, 22 miles below Columbus, to a point about two miles below Omaha ~ridge, 39 miles below Columbus. (For the location of the various exposures described, see sketch map of the river, figure 6, p. 79.)
The upper 50 feet of strata exposed at Chimney Bluff, Chattahoochee River, is regarded as the probable base of this division. (See detailed section, p. 122 of this report.) The material consist of yellowish, sandy, marine clay (dark greenish gray where unweathered in nearby ravines) containing a few imperfect prints of fossils. There is no structural break between this and the underlying beds, the relation being that of conformity. The base of the Tombigbee sand, as interpreted, at the stage of water when visited (about normal) was 35 feet above water level.
The fossils listed below have been recognized from the Tombigbee sand at Chimney Bluff:

132

GEOLOGY OF THE COASTAL PLAIN

Chattahoochee River, Chimney Bluff, Chattahoochee County, Ga., 22 miles below Columbus, Ga. T. W. Stanton and L. lV. Stephenson, collectors.

- - - - - - - - - -- - --- ---------

Mollusca:

Cucullaea sp. . .

Inoceramus sp. .

Crassatellites sp. . . . .

.

Cyprimeria depressa Conrad ..

Aphrodina sp. . . . . . . . . .

Corbula carolinensis Conrad . .

Undetermined gastropod . . . .

Locality No.
-;~~s~T L~:fo~s.
.\ - x~---:----
1 X I X .I X I X . I X I X .I X I .I X I I Xj

At the Racepasses, about 231/2 miles below Columbus, left bank; the base of the Tombigbee sand is 12 feet above water level. (See detailed section, p. 12 3 of this report.) The materials here consist of 14 feet of dark, greenish gray, compact, sandy clay, containing casts of pelecypods, among which Pecten burlingtonensis Gabb was recognized. At this place also the relations between the two divisions appeared to be that of conformity.
At Big Bend, 24lj2 miles below Columbus, right bank, a few feet of gray, marine sand overlies 12 to 15 feet of laminated clays and sands. The former is referred to the Tombigbee sand. The Tomhigbee materials are overlain by Pleistocene terrace deposits. At one point a mass of slightly indurated Tombigbee sand has slipped into the river, being partially exposed at low water, from which were collected the following fossils :

Locality No. 5888.-Big Bend 2..Ph miles below Columbus, Ga.,
right bank. L. W. Stephenson, collector.

Mollusca: Cucullaea .sp. Inoceramus sp.
Exogyra ponderosa Roemer
Pecten sp. Anomia sp. nov. (same as sp.
nov. from Snow Hill, N.C.)

Etea carolinensis Conrad Lucina glebula Conrad ? Cardium sp. Cyprimeria depressa Conrad Aphrodina sp.

Below Big Bend the Eutaw formation is represented by beds of the Tombigbee member only.
A bluff at Planters Landing, 25 miles below Columbus, presents at its base 25 or 30 feet of dark gr'een, finely arenaceous, marine clay, containing fossil remains. A conspicuous layer made up of

EUTAW FORMATION

133

specimens of Exogyra ponderosa: Roemer occurs 12 or 15 feet above zero water level. Of the fossils collected here the following were identified:

Lac. No. 5389.-Planters Landing, 25 miles below Columbus, Ga.,

left bank. L. W. Stephenson, collector.

Vermes:
Hamulus major Gabb Molusca: Cucullaea sp. Nemodon sp. Inoceramus sp. Ostrea sp. Exogyra ponderosa Roemer Lima sp.
Anomia argentaria Morton Etea carolinensis Conrad

Crassatellites sp. Lucina glebula Conrad ? Cardium (Trachycardium) alaba-
mense Gabb ? Cyprimeria_ depressa Conrad Cyclothyris ? Aphrodina sp. Cymbophora lintea (Conrad) ? Corbula carolinensis Conrad ?
. Turritella quadrilira Johnson ?

At Banks Landing, 26lj2 miles below Columbus, left bank, the bluff reveals 25 or 30 feet of marine materials referable to the Tom-

higbee member, consisting of light gray, calcareous clay and glaucon-

itic sand, with indurated, concretionary, calcareous layers several

feet apart. (See plate XV, A.)

Fossils are fairly numerous, and the following were collected and

identified:

Chattahoochee River, Banks Landing, Stewart County, Ga., 261h miles below Columbus, Ga. Collector, L. W. Stephenson.

Coelenterata:
Undetermined coral . . . . . . . . Vermes:
Serpula sp. (nearly straight tube) Hamulus major Gabb . . Hamulus onyx Morton ..
Mollusca: Nucula sp. (cf. nov. from Snow Hill, N. C.) Nucula sp. . . . . . . . . Leda pinnaforma Gabb ? Leda longifrons Conrad . Leda sp. (cf. L. gabbana (Whitfield)
Breviarca saffordi Gabb ? . . . . . . Breviarca (cf. B. umbonata Conrad) Nemodon sp. nov. . . . . . . . . Gervilliosis ensiformis (Conrad) Perna ? . . ..... . - Inoceramus sp. . . . . .
Ostrea cretacea Morton Ostrea plumosa Morton

Locality Number

I 5390

6406

I
X

I X
X IX
X

X

X

X

X

X

:I X X I

:II

I X

X IX

X x,

:I I I

X

.. .

X

X

X IX

I I X

134

GEOLOGY OF THE COASTAL PLAIN

Locality Number

5390 1

6406

Gryphaea vesicularis Lamarck ? (young)

.I X I

Gryphaea aucella Roemer Exogyra ponderosa Roemer . . . . . . . .

:\ I ~

Exogyra ponderosa var. erraticostata Stephenson . I

I X

Trigonia sp. .

.

.

I X I X

Pecten quinquecostatus ( Sowerby) Pecten simplicius Conrad

:I ~ \ X

Pecten burlingtonensis Gabb Pecten sp. Lima reticulata Morton Anomia argentaria Morton

I . I X

. I I

X

. I

I

X X

Anomia sp. nov. (same as sp. nov. Snow Hill, N. C.) I x I x

Liopistha sp. .

.I X I X

Veniella conradi (Morton) .c.tea carolinensis Conrad

:I I ~

vetericardia crenalirata (Conrad)

Crassatellites sp. (cf. C. carolinensis Conrad)

Tenea sp. . . . . . .

. ..

Cardium (Trachycardium alabamense Gabb)

Isocardia sp..

Cyprimeria depressa Conrad

Aphrodina ? . . .

Legumen' planulatum (Conrad)

Linearia metastriata Conrad ..

Cymbophora lintea (Conrad)

Corbula crassiplica Gabb

Corbula sp. . . . . . . . . . . . . . . . .

:I ~ I ~
.I X
:I I.~

I I X

:I. I X

X X X

.I X

I .

.

.
.

I I

x X

x

1 I Dentalium sp. nov. (cf. new species from Owl Creek, 1

1

Miss.)

x

Astralium ? . . . . . . . . .

.x x

Lunatia obliquata M. & H. Lunatia sp.

I I 1 x
x1

Turritella quadrilira Johnson

. x \x

Pterocerella tippana Conrad ?

. I

x

Anchura sp. . Mortoniceras sp. (aff. M. texanum Roemer) Undetermined gastropods

.,

\ x

.

x

.I x

A biuff near the upp~r end of Snake Shoals, left bank, 29 or 29lj2 miles below Columbus, presents materials very similar in appearance
to those at Banks Landing. At the sharp bend to the left just above the mouth of Snake Creek,
right bank, 30 miles below Columbus, a prominent bluff reveals materials of the same character as the preceding. Good specimens of Exogyra ponderosa Roemer occur here. See plate XI, B, opposite

page 120.) At' Blufftown, 3114 miles below Columbus, the river strikes
against a hill having a height of about 195 feet above zero water
level. Only the basal 40 feet of the bluff is well exposed, but from

EUTAW FORMATION

135

poor exposures the follmving section has been made out rongh1y: (See plate XII, A.)

Section at Blufftown> Chattahoochee Riter, 31 1/4 miles below Columbus, Ga.> left bank.

Upper Cretaceous
Ripley formation (Cusseta sand member).
4. Red and yellow, unconsolidated sand, containing small pebbles and thin limonite crusts . . . .
(Typical marine beds)
3. Gray, calcareous, marine sand with some fossils Eutaw formation (Tombigbee sand member).
2. Gray, calcareous, glauconitic sand with indurated, nodular, concretionary layers several "feet apart,
about . . . . . . . . . . . . . . . . . . . . . 1. Gray, calcareous, finely arenaceous, fossiliferous
clay, about . . . . . . . . . . . . . . . . . .

Feet. 100 50
35 10

Layers Nos. 1, 2, and 3 of the preceding section constitute part~. of Veatch's "Bluffto\vn marl."
Near the top of layer X o. 3 \vere obtained Ostrea plumosa Mortm1, a young individual of Bxogyra, with costae, and Anomia sp. nov. (cf. new species from Snmv Hill, N. 0.). The fossils listed below were obtained from layers Nos. 1 and 2; but the principal fossil bed is layer No. 1.
The Tombigbee sand and the overlying Ripley formation are conformable, and the materials above and below the dividing line, as indicated in the above section, are very similar physically. The division is made upon paleontologic grounds, and principally upon the evidence of a fairly typical though small specimen of Exogyra, with costae, in layer No. 3, \vhich in western Alabama and eastern central Mississippi is not known to occur so low as the Tombigbee sand. One or two species in layers Nos. 1 and 2 are relied upon as evidence that this portion of the section should be referred to the Tombigbee sand. A future more perfect understanding of the vertical range of the included forms may establish the necessity of raising or lowering this line of division.

136

GEOLOGY OF THE COASTAL PLAIN

Chattahoochee River, bluff at Blufftown, Stewart County, Ga., 31% miles below Colu'mbus, Ga. Collectors, T. W. Stanton and L. W. Stephenson.
Less than 45 feet above zero water level:

' Locality Nnmbers

T.w.s.l L.w.s.l L.W.S.

844

5392

fA05

Vermes:

Serpula sp. (nearly straight tube)

X

Hamulus major Gabb ..

X

Mollusca:

~ucula percrassa Conrad

X

Nucula eufalensis Gabb

Leda sp. .

. ..

. I

Cucullaea carolinensis Gabb . . .

X

Trigonoarca sp. (young individual ?)

Perrisonota protexta Conrad

Breviarca umbonata Conrad

B;eviarca saffordi (Gabb) ?

~emodon sp. nov. . .

X

X

Area sp....

X

Barbatia (Polynema) lintea Conrad

X

Glycymeris? sp. nov. ?

X

X

Gervilliopsis ensiformis (Conrad)

X

X

Perna sp. nov.

X

X

Inoceramus sp. .

X

X

X

Inoceramus sp. (large cast)

X

Pteria petrosa (Conrad)

X

Ostrea plumosa Morton ..

x? x

Ostrea sp. nov. (same as sp.

Banks Landing, ~- C.) ..

X

Gryphaea sp. (small) ..

X

Exogyra ponderosa Roemer ..

X

X

X

Trigonia eufauensis Gabb .

X

x?

Pecten burlingtonensis Gabb

X

Pecten argillensis Conrad ? ..

x?

Lima sp. ( cf. reticulata Forbes)

X

X

Anomia argentaria Morton

X

I Anomia sp. nov. (same as sp. nov. from

Hill, N. C.)

Snow: X

X

X

Liopistha sp. .

X

Veniella conradi (Morton) Etea carolinensis Conrad .. Venericardia ?

I X

X

X

.I X

X

X

.I X

~o:n~a~) I Crassatellites sp. (cf. C. carolinensis
Arena carolinensis Conrad

X
: :

X

X X

Lucina sp. nov. ? . . . . .

X

X

X

Cardium alabamense Gabb
Cardium eufaulense Conrad . Cardium spillmani Conrad .

I X X

I X

. I

X

X

Cardium (two undetermined species) Isocardia sp.

:I

X X

Cyprimeria depressa Conrad

I X

X

X

Aphrodina regia Conrad ? (young indiv.) . I X X

GEOLOGY OF T HE C0 .4. S 7'A. L PLA I N OF GE ORGTA..

PL.lTE }I.I/1.

B. CUT Or SEABOARD AIR LINE RAILWAY, THREE ::UJT, ES EAST OF CUSSETA , SHOWY ' 0 WEA'l'HERED A ' 0 AND LA:\1INATED LAY BEDS OF 'J'HE C . E'J'A AND MEMBER OF THE RIPLEY FORMATION.

EUTAw' FORMATION

137

Locality Numbers

Aphrodina sp. ? . . . . . . . . . . Cyclothyris alta Conrad ? . . . . . . . Legumen planulatum (Conrad) ..... . Linearia sp. ( cf. L. carollnensis Conrad) . Linearia sp. . . . . . . . . . Leptosolen biplicata Conrad . Schizodesma appressa Gabb .. Corbula crassiplica Gabb . . Corbula carolinensis Conrad Corbula (otner species) ... Dentalium ripleyanum Gabb Cadulus obnutus Conrad . Astralium ? . . . . . . . . Capulus ? . . . . . . . . . . Lunatia obliquata M. & H. . Gyrodes, sp. . . . . . .' . . . Turritella quadrilira Johnson .. Turritella sp. . . . . . . . . . . Turritella sp. . . . . . . . . . . Pterocerella tippana (Conrad) ? Anchura decemlirata Conrad ? .
Anchura sp.... Nautilus sp. nov. (large) Placenticeras ? . Scaphites ? . Arthropoda: Crabs claws . Vertebrata: Lamna texana Roemer Vertebrae of fish . . .

T.w.s.i L.w.s. \ L.W.S.

844

5392

6405

:\ X

X

X

X

X

X

X

I X

X X

~ X

X
:I X

X IX

X IX

I X

X

X

X

X I X IX
I X

I X
X I

X IX

IX I X I

. I

I X

:I I X \ X IX IX

. I
j
I

IX I X I X
I I
I X I I

I I I

X

. I

X

X

.About one mile below Blufftown, in materials similar to those composing layers Nos. 1 and 2 at that place, the :following species were collected:

Locality No. 5393.-0ne mile below Blufftown, Ga., 32 miles below Columbu~, Ga. L. W. Stephenson, collector.

Mollusca:
Cucullaea carolinensis Gabb ? Ostrea sp. Pecten sp.

Etea carolinensis Conrad Aphrodina regia Conraa ? (young) Legumen planulatum Conrad

From Blufftown to Omaha, 37 miles below Columbus, the materials appearing in the bluffs are similar to those in layers Nos. 1 and 2 o:f the section at Blufftown. They consist o:f compact, calcareous sands and clays with indurated, calcareous layers two to 10 :feet. apart. These layers are nearly horizontal, but are seen to undulate slightly, in places to the extent o:f several :feet o:f vertical distance. There is,

138

GEOLOGY OF THE COASTAL PLAIN

however, a slight general dip down stream, amounting perhaps to

several feet to the mile.

About one-eighth of a mile below the bridge of the Seaboard Air

Line Railway at Omaha, the following fossils were colleCted in a

layer five to eight feet above water level:

.

Loc. No. 539.4-.-0ne-eighth mile below Omaha Bridge ( S. A. L.) and about 37 miles below Columbus, Ga. L. W. Stephenson, collector.

Vermes: Serpula sp.
Mollusca: Nucula percrassa Conrad ? Cucullaeae ap. Nemodon ? Trigonia eufalensis Gabb ? Pecten burlingtonensis Gabb Cymella bella Conrad Veniella conra'di (Morton) Crassatellites sp.

Cardium ( Trachycardium) alabamense Gabb ?
Cyprimeria depressa Conrad Cyclothyris alta Conrad Cyclothyris carolinensis Conrad ? Legumen planulatum Conrad Corbula carolinensis Conrad Turritella trilira Conrad Tudicla (Pyropsis) perlata Conrad ? Gyrodes ?
Vertebrata: Otodus appendiculatus Agassiz

i\1 arine materials with indurated, calcareous, concretionary layers, referable to this division, were observed for two miles below Omaha, to the bend to the left below the mouth of Hatchachubbee Creek, 39 miles below Columbus. At the latter place there is a decided reverse dip to the stratification planes amounting to several degrees. The Tombigbee sand member is believed to pass finally beneath water level between this point and Florence, three miles below, for at the latter place beds referable to the Ripley formation make up the entire Cretaceous portion of the bluff.

East of Chattahoochee River.-The Tombigbee~member of the formation outcrops in a belt only a few miles wide, extending from Chattahoochee River in a northeasterly direction through Chattahoochee County into :Marion County. In the latter county the member probably loses its identity as a massive, calcareous, marine formation, by horizontal mergence into coarser sands and clays of shallow-water
origin. In Chattahoochee County the member has been studied at several
places east of the river. The following section \Yas made along the Columbus-Lumpkin road, just north of Jamestown:

Section Columbus-Lumpkin Road, northward-facing slope of Sa,nd Branch, 18 miles south of Columbus, near Jamestown postoffice.

Upper Cretaceous. Ripley formation (Exogyra ponderosa.zone). 12. Reddish, massive, medium-grained, ferruginous,
marine sand, partially indurated . . . . . . .

Feet. 5

EUTAW FORMATION

13~

11. Coarse, reddish and yellowish, loose sand . . . .

3

10. Fine, micaceous, unconsolidated sand, streaked

with yellow and purple . . . . . . . . . . .

20

9, Dark, laminated, finely micaceous clay . . . . . 6 in. to 1

8. Fine, micaceous, greenish gray, argillaceous, mar-

ine sand filled with soft pelecypod casts, with

some lenses of unfossiliferous, gray sand, and

a thin layer of dark, laminated clay, two feet

above base . . . . . . . . . . . . . . . . . .

10

7. Greenish gray, argillaceous sand with numerous

small, short, interlocking clay laminae . . . .

6

6. Dark, finely-arenaceous, thinly laminated clay .

12

Eutaw formation (Tombigbee sand member, Exogyra

ponderosa zone). _

5. Greenish gray, argillaceous, massive sand, with

numerous soft casts . . . . . . . . . . . . . .

5

4. Dark, laminated, micaceous clay interstratified

with lenses and layers of light greenish gray,

fine, micaceous sand reaching a maximum thick-

ness of three feet. Some fossil casts . . . . .

17

3. Dark greenish gray, extremely micaceous sand

with occasional calcareous concretions. Con-

tains an abundance of decayed fossil shells . .

11

2. Similar to layer No. 3, but light greenish gray in

color. Contains soft shells . . . . . . . . . .

10

1. Poorly exposed to base of hill, but consists for the

most part of greenish gray, massive, non-fossil-

iferous marine sand . . . . . . . . . . . . . .

22

The dividing line between the Eutaw and Ripley formations has been placed rather arbitrarily at the point indicated in the above section, and future work may demonstrate the necessity of placing it at some other level.
The fossils given in the list below were obtained from layers Nos. 2 and 3.

Locality No. 6411 a-b.-Columbus-Lumpkin road, south side, about
18 or 18lj2 miles sauth of Columbus, Ga. L. W. Stephenson, col~ lector.

Mollusca: Nucula sp. (cf. sp. nov. from Snow Hill, N. C.) Exogyra ponderosa Roemer Trigonia ,eufalensis Gabb Anomia sp. nov. (same as sp. nov. from Snow Hill, N. C.)

Veniella sp. (cf. species from Hodges Mill, S. C.)
Cyprimeria depressa Conrad Cymbophora lintea (Conrad) Schizodesma appressa Gabb ? Corbula carolinensis Conrad Turritella quarrilira Johnson

Another exposure of the member is furnished by a cut of the Seaboard Air Line Railway, two and one-half miles northwest of Cusseta at the 16th milepost (south of Columbus). The materials consist of about 10 feet of dark gray, marine sand, with a layer of nodular lime concretions near the base. (See plate XII, B, opposite page 128.) The lower two or three feet, including the concretions, is fossiliferous. The determinable forms are listed below:

140

GEOLOGY OF THE COASTAL PLAIN

Locality No. 5379.-Two and one-half miles northwest of Cusseta,
Ga., in cut of Seaboard Air Line Railway, Milepost 16. L. W. Stephenson, collector.

Mollusca:
Cucullaea sp. Inoceramus sp. Inoceramus sp. Breviarca sp.
Exogyra ponderosa Roemer Exogyra ponderosa var. erratis-
tata Stephenson Pecten sp. nov. (cf. sp. nov.
from Snow Hill, N. C.)
Anomia argentaria Morton

Liopist::ha alternata Weller Veniella conradi Morton Etea carolinensis Conrad Lucina glebula Conrad Cardium sp. (cast)
Cardium alaobamense Gabb ? Cyprimeria depressa Conrad Aphrodina sp. Corbula carolinensis Conrad Turritella trilira Conrad

One-half mile nm-thwest of Cusseta on the same railroad, the following forms were obtained in the form of casts, from a black clay at the base of a cut:

Locality No. 5380.-0ne-half mile northwest of Cusseta, Ga., in cut of Seaboard Air Line Railway. L. W. Stephenson, collector.

Mollusca:

Cymella bella Conrad :Schizodesma appressa Gabb
Undetermined pelecypod casts

This horizon is near the top of the Tombigbee sand and probably occupies approximately the same stratigraphic position as the fossiliferous layers Nos. 2 and 3, in the section near Jamestown described on p. 114 of this report.
The Tombigbee sand, as such, has not been traced with certainty far beyond the boundary of Chattahoochee County into Marion County. Veatch has noted an exposure of black micaceous clay near the western border of the latter county which is pelieved to represent this division. It is believed that the massive, marine beds disappear in Marion County by horizontal mergence into irregularly bedded sand and clays of shallow-water origin.

CORRELATION
The present attempt to establish the age and geological position of the beds here referred to the Eutaw formation, in terms of better known sections outside of Georgia, is made partly on the basis of their contained animal and plant remains, and partly on the basis of their stratigraphic position with reference to overlying beds, the paleontologic characters of which are such as to permit of more accurate correlations.
The studies furnishing the paleontologic data for correlation have been of a preliminary character and it is to be expected that the exhaustive studies of the fauna of the region soon to be prosecuted will

EUTAW FORMATION

141

show the necessity for many changes in nomenclature of the fossils, and will reveal some errors in the determinations of genera and species. It is also to be expected that some species now regarded as restricted in range within certain limits will be found to occur in higher or in lower horizons. But this lessening of the number of restricted forms will probably be offset by the discovery of new restricted forms, and by the recognition of specific differences in forms now regarded as having wide vertical ranges. It is believed, however, that such changes as are found necessary will be of minor importance as regards their effect upon the major conclusions reached through these preliminary studies.
The lists of Eutaw species from Chattahoochee River and from Georgia, given on preceding pages, fall into two sets: first, those from horizons in the lower 100 or 150 feet of the formation; and second, those from the Tombigbee sand member which makes up the upper 120 feet of the formation. The two sets will be considered separately.

Basal beds of the formation.-The following species of invertebrate fossils, 16 in number, have been identified from the beds composing the lower 100 or 150 feet of the formation:

Nucula percrassa Conrad Perna sp. nov. Ostrea cretacea Morton Ostrea sp. nov. (cf. sp. nov. from
House Bluff, Alabama River.)
Ostrea sp. nov. ? (aff. 0. lugubris Conrad)
Exogyra upatoiensis Stephenson Pecten sp. nov. (same as at Snow
Hill, N. C.)

Anomia sp. nov. (same as at Snow Hill, N.C.)
Pholadomya sp. nov. Etea carolinensis Conrad Cyprimeria depressa Conrad Baroda sp. nov. Leptosolen biplicata Conrad Cymbophora lintea (Conrad) 'Corbula carolinensis Conrad Placenticeras sp. (aff. P. gultdalupae
Roemer)

Of the species listed the following five range upward throngh the

Tombigbee sand and the Ripley formation, and are, therefore, of no

value in close correlation:

Nucula percrassa Conrad Etea carolinensis Conrad Cyprimeria depressa Conrad

Leptosolen biplicata Conrad Cymbophora Iintea (Conrad)

Corbula carolinensis Conrad ranges up into but not above the zone of Exogyra ponderosa of the Ripley formation. In North Carolina Corbula carolinensis is found in the invertebrate-bearing beds of the upper part of the Black Creek formation. In New Jersey a nearly related, if not identical form, Corbula bi,sulcata Conrad, occurs in the Magothy formation ("Cliffwood clay"), and in the :Merchantville clay marl and the Woodbury clay (basal formations of the Matawan). In western Alabama it occurs in the Ent~w formation at Finches

142

GEOLOGY OF THE COASTAL PLAIN

Ferry, and in Mississippi :five and one-half miles east of Booneville,

in glauconitic sands which fall within the zone of Exogyra ponderosa.

The species is of value therefore, only as indicating an age greater

than that of the extreme basal beds of the zone of Exogyra costata.

In the Chattahoochee region Ostrea cretacea Morton occurs spar-

ingly in the overlying Tombigbee sand. It is abundant, however, in

the Tombigbee sand in central and western Alabama. In North

Carolina the species occurs abundantly at Kerrs Cove, Black River,

and sparingly at a number of other localities in the Black Creek for-

mation. From the evidence furnished bv other forms it is believed that these Black Creek localities corresp~nd in stratigraphic position

to that part of the zone of Exogyra ponderosa which lies above the

Tombigbee sand in the Chattahoochee region. In New Jersey the

species occurs in the Magothy formation. This form appears, there-

fore, to have about the same range, and consequently the same sig-

nificance, as Oorbula carolinensis.



Pecten sp. nov. and Anomia sp. noY. range up through the Tom-

higbee sand into the basal beds (Exogyra ponderosa zone) of the Rip-

ley formation. Both occur in the marine invertebrate-bea-ring beds

of the Black Creek formation in North Carolina. Ostrea sp. nov.

(probably same as sp. nov. from House Bluff, Alabama River) is

questionably referred to an undescribed species occurring in abun-

dance at the top of the Tombigbee sand at House Bluff, Alabama

River, Ala. Perna sp. nov. ranges up into the Tombigbee sand. This

species is not known outside of the Chattahoochee region, although

representatives of the genus occur in the Black Creek formation of

North Carolina. Ostrea sp. nov.? (aff. 0. lugubris Conrad) is new

to the ea1:1tern Gulf Cretaceous. Ostrea lugubris Conrad/ with which

it is compared, is known only from the Eagle Ford formation of

Texas. Placenticeras sp. (c. P. guadalupae Roemer) appears to be

closely related to, but is not identical with PlacPnfir.rras guadalupae

Roemer, a form common in the Tombig-hee sand (M ortoniceras

horizon), and in the upper part of the Austin chalk of Texas.

Exogyra upatoiensis Stephenson,' Philadomya sp. nm'., and Baroda

sp. nov. have not been fonnd outside of the basal beds of the Eutaw

formation in the Chattahoochee region.

To summarize, five of the 16 species range upward into the

Exogyra costata zone of the eastern Gnlf region, and 11 are restricted

below that zone and its equivalents. Of the 11 reRtrictAd forms four

range upward into the basal beds of the Ripley formation (Exogyra

'Since this report was written, good specimPns of an oystPr closely related to Ostrea lugubris Conrad, and good spPcimPns of Ewoqyra upntoien.i Stephenson, have been recognized In well samples ohtainPd from a deep well at Charleston, S. C., at 1lepths of between 1,974 and 2,007 feet. The horizon from which they were taken 1loubtless 'corresponds In age to the horizon which has yielded the fauna of the basal beds of the Eutaw formation in the Chattahoochee region.

EUTAW FORMATION

143

ponderosa zone), two range into thE! Tombigbee sand, and five are restricted to the basal Eutaw beds.
The basal Eutaw beds lack entirely the species which are regarded as characeristic of the Exogyra costata zone. They also lack certaiu species which are common in the Exogyra ponderosa zone, which includes the Tombigbee sand and a part of the overlying Ripley formation, such as Exogyra ponderosa Roemer and Gryphaea aucella Roemer. The five forms restricted to the beds of this formation, since they are all new to science, afford but little positive evidence of the age of the terrane. However, the beds in which they are found are known to occupy a position stratigraphically lower than any other marine invertebrate-bearing beds thus far discovered in the eastern Gulf region, and, for this reason if for no other, the fauna must be regarded as the oldest of its kind known in the region. The new species, Exogyra upatoiensis Stephenson, which occurs in the marine beds near the base of the formation, has a markedly different surface sculpture from the other known species of this genus in the Atlantic and Eastern Gulf Cretaceous. The presence of this species and the presence of the fluted oyster, related to Ostrea lugubris Conrad, which occurs in the Eagle Ford formation of Texas, may perhaps be considered paleo'ntologic evidence of the greater age of the fauna. Since the conditions of the preservation of one species of oyster are as favorable as they are for the preservation of any other species of the same family, this i1ew species of Exogyra and the fluted oyster would be expected to appear in the collections from the overlying Tombigbee sand if, in this region, they had lived contemporaneously with the oyster, Exogyra ponderosa Roemer, which is common in that terrane.
From the range determinations as above stated, the following conclusions have been deduced: The fauna present in the basal beds of the Eutaw formation possesses elements in common with the Cretaceous faunas of. higher horizons in the same region; however, in passing from this basal horizon to the successively higher horizons the number of common species diminishes. Although showing these relationships the fauna contains elements distinct from anything known in the higher horizons. Comparing this fauna with Cretaceous faunas to the northward it is found that it bears about the same relationship to the invertebrate fauna present in the upper part of the Black Creek formation of the Carolinas that it does to the fauna of the basal beds of the Ripley formation (Exogyra ponderosa zone) in the Chattahoochee region. The basal Eutaw beds are therefore lower, stratigraphically, than the invertebrate-bearing beds of the Black Creek formation, and, in the opinion of the writer, correspond approximately to the non-invertebrate bearing beds of that formation. The actual evidence for a comparison of the basal Eutaw fauna with

144

GEOLOGY OF THE COASTAL PLAIN

the Cretaceous faunas of New Jersey is slight, but combined with evidence furnished by the faunas from overlying horizons there seems
t" be sufficient grounds for correlating the containing strata approximately with the Magothy formation.
The invertebrate-bearing basal Eutaw beds of the Chattahoochee region are represented to the 'Yestward in Alabama and Mississippi by corresponding basal Eutaw strata in which no well-preserved invertebrates have as yet been discovered.
Fossil plants have bee)l obtained at several horizons in that part of the Eutaw formation below the Tombigbee sand member. E. W.
Berry, who studied them; recognized 27 species from the terrane. He furnishes the following statements, quoted from an unpublished man-
uscript on the fossil plants of Georgia, giving his views of the significance of the plant remains in correlation:
It is clear that the flora of the Eutaw formation of Georgia is of the same age as the Magothy flora of the northern Coastal Plain and the Black Creek flora of the Carolinas. It has much in common with the much more extensive Tuscaloosa flora of western Alabama, and these beds of Georgia are probably homotaxial with more or less of the upper Tuscaloosa of western Alabama. Whether the Tuscaloosa flora of western Alabama is essentially a unit and accidents of preservation account for its greater richness, or whether the plant beds of this fromation in northwestern Alabama are appreciably older, is a question which can not be answered positively until the flora is critically studied.
The flora of the Eutaw in Georgia is strictly comparable with that of the upper Tuscaloosa of western Alabama, as for example, the flora of which a few species are preserved near Havana in Hale County, Ala., and which lies on the border line between the Tuscaloosa and Eutaw formations, as delimited in that area by Professor Smith, the State Geologist.
The evidence furnished by the plants as interpreted is at least in part agreement with that afforded by the invertebrates, although in
the opinion of the present writer the Magothy flora, with which Georgia flora is compared, persisted to a later time in the region of
the Carolinas, and,. as will be shown later, also in Georgia, than in New .Tersey; for the fauna present in the upper part of the Black Creek formation seems to indicate clearly that this terrane includes
representatives of both the Magothy and the overlying Matawan
formations. The flora in the upper part of the Tuscaloosa formation in Hale
County, Ala., with which Berry compares these Georgia species, oc-
curs in beds the lithologic character of which would admit of their l:>eing considered as belonging to either the upper part of the Tusca-
loosa formation, or to the basal portion of the overlying Eutaw for-
mation. The following vertebrate species, all sharks, have been collected
from the Broken Arrow Bend exposure near the base of the Eutaw
formation:

EUTAW FORMATION

145

Corax falcatus Agassiz Lamna texana Roemer

Otodus appendiculatus Agassiz

As these species are all known to have a wide stratigraphic range_ .they have no value in close correlation.

Tombigbee sand member.-The beds on Chattahoochee River, here
referred to the Tombigbee sand, are so correlated chiefly on the evi-
dence of certain species of invertebrates, but in part upon their phy-
sical characters and relations. Lithologically, the materials agree in
all essential respects with those of the type region in Mississippi, al-
though the content of lime is greater. The formation is immediately
underlain by sands and clays containing a considerable percentage of
lignite and in this respect the lower relations are in exact agreement
with those of the type region. In the type region the Tombigbee
sand is immediately overlain by the Selma chalk. In the Chatta-
hoochee region the Selma chalk is not present as such, but is represented by marine sands and clays, the bc~ds immediately abort> t}w
Torribigbee sand being of marine origin and similar to the beds of
the Tombigbee member itself.
The Tombigbee sand member forms the basal portion of the zone of Exogyra ponderosa of the 1Jpper Cretaceous deposits, of which the
lower one-third or one-half of the Ripley formation forms the upper
part.
Omitting a number of questionably identified species, 57 species
of invertebrates haYe been identified from the Tombigbee member in
the Chattahoochee region as follows:
1. Serpula sp. (nearly straight tube) (Rc) 2. Hamulus onyx Morton (Rc, Rp) 3. Hamulus major Gabb 4. Nucula percrassa Conrad (Rc, Rp, Eb) 6. Nucula eufalensis Gabb (Rc) 6. Nucula sp. (cf. sp. nov. from Snow Hill, N. C.) 7. Leda longifrons Conrad (Rc) 8. Perrisonota protexta Conrad (Rc) 9. Cucullaea carolinensis (Gabb) (Rp) 10. Breviarca umbonata (Conrad) 11. Nemodon sp. nov. (Blufftown, etc.) 12. Barbatia lintea Conrad (Rp) 13. Gervilliopsis ensiformis (Conrad) (Rc) 14. Perna sp. nov. (Broken Arrow Bend, etc.) (Ec) 15. Ostrea plumosa Morton (Rc, Rp) 16. Ostrea cretacea Morton (Eb) 17. Ostrea sp. nov. (same as at Blue Banks Ldg., N. C.) 18. Gryphaea a'lcella Roemer 19. Exogyra ponderosa Roemer 20. Exogyra ponderosa var. erraticostata Stephenson (Rp) 21. Trigonia eufalensis Gabb (Rc) 22. Pecten quinquecostatus (Sowerby) (Rc) 23. Pecten simplicius Conrad (Rc) 24. Pecten burlingtonensis Gabb (Rp)

146

GEOLOGY OF THE COASTAL PLAIN

25. Pecten sp. nov. (same as sp. nov. from Snow Hill, N. C.) (Rp. Eb.)
26. Lima reticulata Forbes (Rc) 27. Anomia argentaria Morton (Rc, Rp) 28. Anomia sp. nov. (same as sp. nov. from Snow Hill, N. C.) (Rp, Eb) 29. Cymella bella Conrad (Rc) 30. Liopistha alternata Weller 31. Liopistha sp. (aff. F. alternata Weller) 32. Veniella ,conradi (Morton) (Rc, Rp) 33. Etea carolinensis Conrad (Rc, Eb) 34. Vetericardia crenalirata (Conrad) (Rc) 35. Crassatellites carolinensis Conrad ? (Rp) 36. Arena carolinensis Conrad 37. Lucina glebula Conrad (Rp) 38. Cardium eufaulense Conrad (Rc, Rp) 39. Cardium spillmani Conrad (Rc) 40. Cardium alabamense Gabb (Rc) 41. Cyprimeria depressa Conrad (Rc, Rp, Eb) 42. Cydothyris alta Conrad (Rp) 43. Legumen planulatum (>Conrad) (Rc, Rp) 44. Linearia metastriata Conrad (Rc) 45. Leptosolen biplicata Conrad (Rc, Rp, Eb) 46. Cymbophora lintea (Conrad) (Rc, Rp, Eb) 47. Schizodesma appressa Gabb 48. Corbula crassiplica Gabb (Rc) 49. Corbula carolinensis Conrad (Rp, Eb) 50. Dentalium ripleyanum Gabb (Rc) 51. Dentalium sp. nov. (same as sp. nov. from Owl Creek, Miss) 52. Cadulus obnutus (Conra,d) (Rc) 53. Lunatia obliquata Meek and Hayden (Rc) 54. Turritella trilira Conrad (Rc) 55. Turritella quadrilira Johnson 56. Nautilus sp. nov. (large, Blufftown, etc.) 57. Mortoniceras sp. nov. (cf. M. texanum Roemer)
Of the 57 species, 30, marked (Rc) in the list, have been recog-
nized in the zone of Exogyra costata of the Ripley formation in the
Chattahoochee region; 20, marked (Rp), in the zone of Exogyra
ponderosa of the Ripley formation; and 10, marked (Eb), in th0
underlying basal beds of the Eutaw formation. The questionably
identified form, Cmssatellites carolinensis Conrad, although not cer-
tainly identical with the species described by Conrad from Snow Hill,
belongs to a flat type of the genus which does not appear to range
above the zone of Exogyra ponderosa, and is included in the preceding
list because of the value in correlation which this restriction in range
gives it.
The 30 species which haYe been found as high as the zone of Exo-
gyra costata need not be further considered since their great vertical
range rem1ers them of no value in the finer discrimination of age re-
lationships. Twenty-seven of the 57 species are in this region re-
stricted belO\Y the zone of E:rogyra r;ostata of the Ripley formation.
The table giwn below indicates the range of these 27 species, both
within and "'ithont the Chattahoochee region.

EUTAW FORMATION

147

Table showing ranges of the Tombigbee species which in the Chattahoochee region are restricted below the zone of Exogyra costata.

'

i
" I
.. """' s. " E -5
" "' '"" .s g .:<
. "" "til

.0p
..0..

~
i.:,ii

~
~ ..c..c
~.! ~<
~~


~'.s E~
.';:"(:~l
.:soso :'o:";:"...,

t:'biJ...:

-5"50
'0~

:0:;0:'->.g0..
~.,oo

>..C:
...8,8"

-~
a";' ~ E ...."c.,
0

.,:g..: " E. .... ~ """" !!:"&
" .s~

o..C
Ng
"~.'.0c

"" .e....s. " ......, ..,., >~igl"
ooO
_., ,., "'" ""'"' ,.,..., ~~~ "l'l..~c

g:._.oc
.. ..c

... ""' ~"..0c ~"~
ll1 ~

~~-~

.s,8";;;~:
s..c-
";'.]Sf~:

+J : N~0.~.c."~..'.
.e.,~o.;;~:

..c 0 gj .o.. .,,

.~+J Q,)
..C~"'"C
....

~~s
~_g
>< N
~

0
0 N
.E l!
0
;":
0
><
~

.".' ].".
0
-.."5..
0
:"..
..0E..
0"""."'
.""9"'
ll1

>.
" ~ .."...
!!:
z "
'0
.:.s".3.
..0..
..c
~ ~

.>.
.."""..'.
!!:
z "
'0
"~ ' .~"s
~

Hamulus major Gabb Nucula sp. nov. (cf. sp. nov. from Snow

!

I
I

X I

I

I

I' X
I

I

Hill, N. C.)

X I

Cucullaea carolinensis Gabb Breviarca umbonata (Conrad)

X !I
I

x? I

Nemodon sp. nov. ( Blufftown, etc.) Barbatia lintea Conrad

I

X x?

I

Perna sp. nov. (Broken Arrow Bend, etc.) X

i.

i

Ostrea cretacea Morton Ostrea sp. nov. (same as

sp.

nov.

from

X

X X:

X I
X
I
X
X X

Blue Banks Landing, N. C.)

.. Gryphaea aucella Roemer
Exogyra ponderosa Roemer

Exogyra ponderosa var. erraticostatal

Stephenson . .

. . . . .

Pecten burlingtonensis Gabb

Pecten sp. nov. (same as sp. nov. froml

:

X

'

X

X

X

I I

X

I

I
X;

i X iX

X

X

X I
X I x'
I
X
X I xz

Snow Hill, N. C.)

... X X X

X

Anomia sp. nov. (same as sp. nov. from

I

!

Snow Hill, N. C.) . . . . . . . . . . . j X Liopistha alternata Weller . . . . . . .

X

X X

L1i~;r~h~ s~- _n~~- _c~ff-. ~- _a~te_r~a~a _':e~-

!

X
:
'
I

X

x"

Crassatellites carolinensis Conrad

1 :

Arena caro!inensis Conrad Lucina glebula Conrad

i

.. ~,; Cyclothyris lata Conrad
Schizodesma appressa Gabb

I
I
I

Corbula carolinensis Conrad
Dentalium sp. nov. (same as

X

X
xi x?
X x?
X !
'
X'

i

It

I

X

I

X

x? I

X

X

X

X XX

X
I

X x4 X xs

from Owl Creek, Miss.)

I

Turritella quadrilira Johnson Nautilius sp. nov. (large, Blufftown, etc.) 1

'

II

X X

I X

I

X I X XG

I

Mortoniceras sp. (aff. and M. delawarensis

M. texana Morton)

~~e~e.rl

I I

I
i X I

I

I
I x'

'Occurs m the Marshalltown clay-marl of the Matawan formatiOn. 20ccurs in the Merchantville clay-marl, the Woodbury clay, and the Wenonah Rand of the Matawan formation.

occurs in the MerchantvillP clay-marl of the Matawan formation. occurs in the Wenonah sand of the Matawan formation.

'Probably same as Gnrbula bisulcata Conrad which occurs in the Magothy formation, and the Merchantville clay-marl and the Woodbury clay of the Matawan formation.
occurs in the Woodbury clay of the Matawan formation.

'Occurs In the Merchantville clay-marl of the Matawan formation.

148

GEOLOGY OF THE COASTAL PLAIN

Of the 27 species given in the table 10 occur in that part of the overlying Ripley formation included within the zone of Exogyra ponderosa, five occur beneath the Tombigbee sand in the basal beds of the Eutaw formation, and 15 are restricted to the Tombigbee sand member.
To the westward of the Chattahoochee region in Alabama and Mississippi, seven of the 15 restricted species ar~ known to occur in the M ortonicems sub-zone of the Tombigbee sand, seven are known in that part of the zone of Exogyra ponderosa overlying the Mortoniceras sub-zone, and two in the zone of Exogyra costata (Ripley formation of northern Mississippi). The small number of forms common to the Tombigbee sand of the Chattahoochee region, and to the same member to the westward in Alabama and Mississippi, is to be explained by the fact that in the Chattahoochee region the member. is far more prolific in species than elsewhere in the eastern Gulf region; and this palentologic difference appears to be reflected in the lithology, in that the Tombigbee of the Chattahoochee region contains a much higher percentage of calcite than does the typical Tombigbee to the westward.
The forms that are believed to indicate the correspondence in age of the beds under consideration with the Tombigbee sand to the westward in Alabama, and in the type region in Mississippi, are the following: Liopistha alternata Weller, Nautilus sp. nov. (large), and JJ!Iortoniceras sp. (a:ff. M. texana Roemer).
These forms are not known above the M ortoniceras sub-zone in the region, and the Nautilus and M ortoniceras are distributed generally in this horizon from Montgomery, Ala., to Aberdeen, Miss. It i~ ennsidered probable that the genus Mortoniceras does not occur in the Atlantic and Gulf Coastal Plain in beds higher than this horizon.
Of the 15 species restricted to the Tombigbee sand in the Chattahoochee region, seven occur in the invertebrate-bearing beds forming the upper part of the Black Creek formation of the Carolinas, and none in the Peedee sand. The three specimens given above as characteristic of the Tombigbee sand, however, have not been found in the Black Creek beds, and their absence together with the fact that the Black Creek fauna corresponds closely to that of the overlying Exogyra ponderosa zone of the Ripley formation in the Chattahoochee region, is taken as evidence that the Tombigbee sand is slightly lower stratigraphically than the invertebrate-bearing Black Creek beds, or, in other words, that it is represented by a part of the non-invertebrate, bearing beds of the Black Creek formation below the beds carrying
invertebrates. Of the 15 forms restricted to the Tombigbee sand member in the

RIPLEY FORMATION

149

Ghattahoochee region, two occur in the JYiagothy formation and four in the Matawan group of New Jersey. Of the four occurring in the Matawan group one, Liopistha alternata: weller, occurs only in the Merchantville clay marl, the basal formation of the group. Mortoniceras is represented in the New Jersey Cretaceous by M ortoniceras delawarensis (Morton), which is restricted to the Merchantville clay marl. The presence in this formation of Liopistha alternata Weller, and the presence of Mortoniceras which in the eastern Gulf Cretaceous is not known to range above the Tombigbee sand member, are considered evidence that the formation is approximately synchronous with the Tombigbee sand member of the Eutaw formation. It will be observed that not one of the 15 restricted forms occur in the Monmouth formation of New Jersey.
Three species of vertebrate animals have been recognized from the Tombigbee sand of the Chattahoochee region. These are teeth of the sharks, Gorax falcatus Agassiz, Lamna texana Roemer, and Otodus sp.? The two former are wide-ranging forms and are of no correlative value, and the latter is not sufficiently well identified for its value in correlation to be known.
The conclusions deduced from the above statements of range may be summarized as follows :
The Tombigbee sand of the Chattahoochee region while containing many species in common with the overlying Ripley beds, nevertheless contains a few forms of restricted vertical range and extended geographic range, possessing great value in close correlation. On the evidence of these few forms the Tombigbee sand member of the Eutaw formation in the Chattahoochee region is correlated with the Tomhigbee sand of the type region in J\ississippi, and especially with the M ortoniceras sub-zone of that member. Referred to the Carolina Cretaceous the member is believed to be synchronous :with a portion of the Black Creek formation beneath the invertebrate-bearing beds of ' that formation. In New Jersey the Merchantville clay marl is believed approximately to represent the Tombigbee member.
A diagrammatic representation of the age relationships of the Eutaw beds of the Chattahoochee region to Cretaceous deposits else. where in the eastern Gulf region and the Atlantic Coastal Plain, is given in Plate V.
RIPLEY FORMATION
NAME
The name Ripley is derived from the town of Ripley, in Tippah County, Miss., and was originally proposed as the name of a geologic division by Dr. Eugene W. Hilgard1 in 1860. The town of Ripley
lGeology and agriculture of the State of Mississippi: Jackson, Miss., 1860, pp. 62, 83-95.

150

GEOLOGY OF THE COASTAL PLAIN

is situated upon Eocene strata which were erroneously referred by Rilgard to the Cretaceous. However, Cretaceous beds appear in the banks of Tippah Creek within one-half mile of town, where they are overlain by Eocene (:Midway) limestone. This error was corrected by G. D. Harris' in 1896. Layers 1, 2, and 3 of the section given b_y Hilgard,' on Tippah Creek near Hipley, belong to the Cretaceous. Concerning the distribution of the beds of this formation Hilgard says:
"These strata from the Pontotoc Ridge in Mississippi, and Chunnenugga Ridge in southeast Alabama; according to the late researches by Conrad, they also exist at Eufaula, Ala."
Exposures of Ripley strata in the bluffs of Owl Creek, three miles northeast of Ripley, have been rendered classic by the paleontologic researches of T. A. Conrad.'
Although the equivalency of the Cretaceous beds exposed on Chattahoochee River at Eufaula, to the Cretaceous beds in Tippah County, Miss., was recognized by Conrad in 1860, the first investigator to refer this whole series of Ripley beds along the Chattahoochee River to this division was D. \V. Langdon.' He included in his Hipley group an additional 120 feet of strata at the base of the series which in this report are, on paleontologic evidence, referred to the Tombigbee member of the underlying Eutaw formation.
DEFINITION.
Areal disiTibution.-The Ripley formation is exposed on Chattahoochee River in the upper part of the bluff at Blufftown, thirty-one and one-quarter miles below Columbus, Ga., and in the bluffs from Florence, in Ste\Yart County, Ga., to a point not accurately determined near Othos Landing, Ala., about 15 miles below Eufanla. ft extends northeashvard from the river through Georgia in a belt 10 to 14 miles \Yide, including parts of the following counties: Clay, Quitman, Stewart, \Yebster, Chattahoochee, Marion, Schley, Taylor, Macon, Crawford, Houston, Bibb, and Twiggs. In Twiggs, Houston, southwestern Crawford, and eastern Macon counties, the formation is concealed by a relatively thin blanket of overlapping younger strata, referable in part, or perhaps in whole, to the Eocene epoch, except where the latter have been removed by stream erosion.
West of Chattahoochee River in Alabama the formation appears in an area south of that occupied by the Eutaw formation, having a maximum width of 25 or 30 miles, and including parts of Russell,
'The Midway stage: Bull. Amer. Palcon., Vol. 1, No. 4, 1896, pp. 22-25 (136-139), 2Geology and agriculture of the State of Mississippi; Jackson,. Miss., 1860; p.. 87, observations on a group of Cretaceous fossil shells, found in T1poah County, Miss.. with descriptions of fifty-six new species: Jour. Acad. Nat. Sci. Phila., n. s., vol. 3. 1855-58, pp. 323-336, plates 34 and 35. 'Jour. Acad. Nat. Sci. Phila., n. s. vol. 4, 1858-1860, pp. 275-298. 'Bull Geol. Soc. America, vol. 2, 1891, pp. 587-606.

RIPLEY FORMATION

151

Barbour, Macon, Bullock, Pike, Montgomery, Butler, Lowndes, Dallas, Perry, and :Marengo counties. The western boundary of the formation is determined by the horizontal mergence of the beds in that direction into the beds of the Selma chalk.
.Stratigraphic position.-In western Georgia and in Alabama the formation rests with conformable relations upon the Eutaw formation. From Taylor County east\vard to the eastern limits of its occurrence in Twiggs County, the Ripley beds rest unconformably upon Lower Cretaceous strata. The formation is overlain unconformably in both Alabama and Georgia by Eocene strata. This unconformity is an important one and probably represents a long period of time. This is evidenced by the great faunal change which took place during the interval, few if any species having survived from Cretaceous to Eocene time.
In :M:acon, Houston, and southeastern Cra~wford counties the formation is concealed throughout considerable : reas in which it would otherwise appear at the surface, by a relatively thin oYerlap of strata believed to be referable to the Eocene. In Twiggs County the formation passes finally beneath, and is completely overlapped and buried by Eocene deposits.
In narrow areas bordering Chattahoochee, Flint, and Ocmulgee rivers the formation is overlain by thin, snrficial terrare deposits of Pleistocene age.
Lithologic characters.-vVith the exception of portions of the upper parts of the high bluffs at Blufftown and at Stewart's Hill,the materials of this formation exposed in the immediate blufftJ of Chattahoochee River are all of a. strictly marine character. They consist of massive, dark gray or greenish gray to black, more or lrss calcareous, micaceous, pyritiferous, and glauconitic sands and clays, with indurated ledges of calcareous sandstone or impure sandy limestone at vertical intervals of a few feet to 10 feet or more, with, in places, interbedded layers of loose, crossbedded, yellowish, calcareous sands and shell marls of shallow marine origin. Fossils are common as shells or shell prints and at various leYels are sufficiently abundant to form shell marls. The shallow marine phases contain in places numerous fragmentary bones of dinosaurs, mosausaurs, crocodiles, and turtles, together with occasional reptile teeth, great number8 of sharks' teeth of several species, and a few other fish teeth. In the exposures in the vicinity of Woolridge Landing these vertebrate remains are closely associated with an undescribed species of gigantic oyster, and with a large number of other species of mollusks. To the northeastward away from Chattahoochee River in Georgia, the basal portion

152

GEOLOGY OF THE COASTAL PLAIN

of the _formation embracing 200 or 300 feet of strata merges along the stnke of the beds into shallow-water equivalents which differ in their essential lithologic characters from the typical beds. This is the Cusseta sand member described below. The uppermost beds of the formation also merge along the strike both to the northeastward in Georgia and to the westward in Alabama into the similar shallowwater equivalents which are later described as the Providence sand member of the formation.
The Cusseta sand member consists of irregularly bedded, un~on solidated sands, with subordinate cla:v lenses, probably of sound or estuarine origin, but perhaps in part of shallow marine origin. They outcrop at the surface in a belt which inclncles parts of the following counties: Stewart, Chattahoochee. ~Iarion, Schley, Taylor, :Macon, Crawford, Houston, Bibb, and Twiggs. In Stewart and Chattahoochee counties the sands vary from fine to coarse in texture, and are somewhat arkosic. Farther to the northeast in :Marion County the. materials become in general coarser, although rather fine phases are not uncommon. This same predominance of coarse materials holds true throughout the remainder of the area occupied by the member, but as in :Marion ConntY, finer sands are known to occur locally. The clay lenses present in these sands are for the most part light drab, or even white, and massive, and in general resemble the more impure clays of the Lower Cretaceous. Locally, howenr, the clays are thinly laminated. At a few places carbonaceous clays, both massive and laminated, containing considerable percentage"' of comminuted plant remains have been noted, and fossil leaves ha,-e been collected at two such localities. This non-marine phase of the formation was first discriminated by Otto Veatch' in 1909, and was designated by him the Cusseta sand. The division is here given the rank of member. The similarity of the materials of the Cusseta sand member to the shallow-water phase of the Eutaw formation in its eastern extension renders the two formations separable onl; \vith difficulty. The same :is true of this member with respect to the owtlying Providence sand member of the Ripley formation in the region betwren Flint and Ocmulgee rivers.
The Providence sand member consists prrclominantlv of coarse, irTegularly bedded sands with subordinate light-rolored ~lay lenses and layers. In Georgia the member outcrops in a long, narrow belt lying along the southern border of the Cretaceous area, and including parts of Quitman, Stewart, Webster, Marion, Schley, Macon, Houston, and Twiggs counties. In Alabama it is present along the southern
lSecond report on the clay deposits of Georgia: Bull. Geol. Survey of Ga. No. 18. 1909, pp. 82-90.

RIPLEY FORMATION

153

borde: of the Cretaceous area in parts of Barbour, Bullock, and Pike counties.
Although the sands are in general coarse there are finer phases and this is especially true of the beds towards the base of the member, or the zone of transition from the underlying typical marine beds to the overlying coarser beds of this member. Rolled clay balls are numerous at many places in the sands. In Houston County the member contains notable lenses of white clays which have been mined in a small way and which give promise of becoming of commercial importance in the future.
The typical marine beds, th,e "Renfroes marl" of Veatch, which intervenes between the Cusseta and Providence members, is traceable as a narrow belt from the Chattahoochee region through Stewart, Chattahoochee, JYiarion, and Schley counties, to Macon County, where they appear to pinch out, so far as surface outcrops are concerned, between the underlying and overlying shallow-water members. Beyond this point to the eastern limit of the surface occurrence of the formation the two members, each of which has gradually increased its thickness in this direction, are in conformable contact with each other, and together appear to represent the whole thickness of the formation. However, there is evidence that buried representatives of the typical marine beds extend eastward, at least as far as Marshallville, where calcareous beds have been penetrated in a well boring. The Providmice sand was diff~rentiated and named by Otto V eatch1 in 1909.
Strike, dip, and thickness.-The beds of this fqrmation have m Georgia a general northeast-southwest strike. To the west in Alabama the strike is nearly dueeast and west.
That portion of Langdon's' Chattahoochee RiYer section, referred in this report to the Ripley formation, includes layers Nos. 14 to 38. the thicknesses given by him total 948 feet. The beds outcrop at zero water level along the river in an air-line distance across the strike of about 29 miles. The average dip required to produce in this distance the thickness estimated by Langdon is 32 feet to the mile. In order to determine the correct average dip it would be necessary to make a large number of dip observations. It is known, however, that the beds undulate, the dip being less in places and elsewhere amounting to as much as 40 feet to the mile. In the absence of the data necessary for an accurate calculation of the thickness, Langdon's figure may be regarded as a probable close approximation to the true amount.
1Qp. cit., pp. 82-90. Geological Survey of Alabama, Geology of the Coastal Plain of Alabama, 1894, pp. 439-445.

154

GEOLOGY OF' THE COASTAL PLAIN

A well at Buena Vista, 11arion County, penetrateJ strata believed to be referable to this information, to a depth of 583 feet. No other wells properly located, or of sufficient depth, to give an idea of the thickness of the terrane, have been drilled along the belt of its occurrence, but it is probable that it maintains approximately this thickness to the eastern limits of its areal extent. However, to the south of the belt of outcrop at Albany, in Dougherty County, Ga., Tertiary and Cretaceous strata were penetrated in a well to a derth of 1,320 feet. The upper 500 feet of the section is referred to the Tertiary. The remainder of the strata, 820 feet, should probably be referred in their entirety to the Ripley formation. Besides the Albany well a well at Blakely, Early County, drilled to a depth of 812 feet, passed entirely through the overlying Tertiary strata and entered the Ripley formation at less than 500 feet below the surface, the exact depth at which the Ripley was first encountered, however, being unknown.
Physiographic expression-The general upland surface throughout the areal extent of this formation is a dissected plain, ranging from 400 to 600 feet above sea level. Topographically the region may be said to have advanced to the stage approaching that of maturity, the surface, therefore, being broken and hilly. The formation througout the greater part of its areal extent in Georgia is composed predominantly of beds of a sandy character. A thin, surficial blanket of loose, gray sand, resulting from the weathering and leaching of these sand beds, is almost universally present. In Macon, Crawford, and Houston counties the formation is concealed over considerable areas by a thin overlap of red, ferruginous sand of probably Eocene age. Where the latter is present, and especially in the region surrounding Fort Valley, the surface is remarkably level, and is in strong contrast to the remainder of the belt. In narrow area::; bordering Chattahoochee, Flint, and Ocmulgee rivers the valley sides have bern modified by terracing processes.
Paleontologic characters.-As previously explained,,the typical rna rine beds of this formation contain in many layers an abundance of fossil invertebrate remains, and scattered fragmentary remains of vertebrates.
The formation in the Chattahoochee region is divisible on the basis of the ranges of the contained species of Exogyra into two parts. The lower, embracing approximately the lower one-third to one-half of the terrane, is characterized by the presence of Exogyra ponderosa Roemer; the upper, embracing the remainder of the formation is characterized by the presence of Exogyra cosfa.ta Say. The former is given the name E::rogyra ponderosa zone, and to the latter Exogyra costata zone.

RIPLEY FORMATION

155

Since the species E:rogym Tombigbee sand member of

ponderosa the Euta1v

occurs also formation

in the

thEea;lomgyllrearlpvoir1w~

derosa zone includes this member also.

The formation contains a large number of invertebrate species

which range from the base, or even below the base of 'the terrane, to

its top; but there are in addition numerous species IYith restricted

ranges, some confined abme and some below the horizon separating

the two zones.

DETAILED SECTIONS. (PART 01!' FOR:\IATI0:-.1 INCLUDED WITHIX TilE :;r,O);E OF EXOGYRA PO>..'DEROK.t.)

Chattahoochee Biver (typical marine beds) .-The Hipley formation is exposed on Chattahoochee River in the upper part of the section at Blufftown, 31% miles below Columbus, Ga., in Stewart County, Ga., and in bluffs from Florence, 42 miles below Columbus, to a point near Othos Landing, Ala., not exactly determined, about 15 miles below Eufaula, a total distance by the river of about 44 miles. (For the location of the. exposures described, see sketch map of the river, figure 6, p. 7D.)
The details of the exposure at Blufftown have been deocribed in a section on page 134 of this report. The upper 100 feet of the section is believed to represent the Cusseta sand member of the formation. The next 50 feet, consisting of gray, calcareous, marine sand, with some fossils, is the upper part of the "Blufftown marl" of Veatch, and constitutes the basal portion of the Ripley formation of this report. The following fossils were obtained near the top of this 50-foot divi:;:ion: Ostrea plumosa Morton, Exogyra sp. (young indi' vidual with cost:), Anomia sp. nov. (same as sp. nov. from Snow Hill, N.C.)
This gray sand is similar physically to the materials lo1ver do:wn in the section, but the latter contain some fossils which in the light of our present knowledge of their range do not occur at horizons higher than the Tombigbee sand or the extreme base of the Selma chalk.
Below Blufftown to a point two miles below Omaha the river bluffs reveal the beds of the Tombigbee sand member only. From here to Florence there are no exposures, but at the latter place the following
section appears :

Section at Florence, Chattahoochee River, left bank, 42 miles below

Columbus.
Pleistocene (terrace deposit) 3. Yellowish sandy clay and sand with gravel band at base . . . . . . . . . . . . . . . . . . . . (Unconformity.)

Feet. 12 to 15

Upper Cretaceous Ripley formation (Exogyra ponderosa zone).

156

GEOLOGY OF THE COASTAL PLAIN

2. Gray to greenish gray, marine sands and clays,

more or less glauconitic, micaceous, and calca-

reous in the different layers. Several rows of

calcareous concretions occur near the base.

Fossiliferous in lower five or six feet. Shells

very soft . . . . . . . . . . . . . . . . . . . 20 to 25

1. Laminated sands and clays with lenses of gray,

yellow, and brown sands and seams of lignite .

lO

The bluff at this place is about one-half mile long, and in this distance the bedding plains are seen to dip gently southward. Of the fossils collected here the following "'ere identified.

Ohatta}wochee River> bluff at Florence, Ste~cart County> Ga. L. W. Stephenson, collector.

Locality Number.

5395

6404

Vermes: ........... .

Hamulus onyx Morton . . Mollus,ca: . . . . . . . . . . .

X

X

Nucula percrassa Conrad .

X

Le,da longifrons Conrad ? .

X

Trigonoarca sp.

X

Area ? . . . . . .

.

Barbatia (Polynema) lintea Conrad

X
x'

Barbatia sp. . . . . . . . . . . . .

X

Ostrea sp. . . . . . . . . . . . . . . . . X

Ostrea sp. nov. (same as large species at Woolridge

Landing) . . . . . . . . . . . . . . . . . . .

X

lilxogyra ponderosa var. erraticostata Stephenson .

X

X

Trigonia sp. nov. (same as at Snow Hill, N. C.) . .

X

Anomia argentaria Morton . . . . . . : . . . . .

X

Crassatellites sp. nov. (cf. C. pteropsls Conrad)

X

Cardium eufaulense Conrad

X

Cyprimeria depressa Conrad

X

X

Aphrodina regia Conrad . .

X

Cyclothyris alta Oonrad . .

X

Cymbophora lintea Conrad .

X

Corbula carolinensis Conrad

X

Undetermined pelecypods

X

Vertebrata:

Crocodilian teeth

X

Lamna sp.

X

Two miles below Fl0rence, 44 miles below Columbus, right bank, there is exposed at the foot of a bluff, 25 or 30 feet of dark gray, micaceous marine clay. A layer of lime concretions occurs about 12 or 15 feet above the base. Fossils, mostly fragile and in a fragmentary condition, occur near zero water level. The horizon is probably about the same as that at Florence.

RIPLEY FORMATION

157

About 46 miles below Columbus there appears at the base of a bluff 10 or 12 feet of dark gray, compact, marine clay with t:~everal layers
of slightly indurated light gray sand, each about six inches in thickness. Fragmentary shells occur near water level.
In the vicinity of Woolridge Landing, 46lj2 miles below Columbus, 131h miles above Eufaula, Ala., there are several interesting ex-
posures. A short distance above the landing on the opposite side of
the river, left bank, the bluff presents the following section:

Section opposite Woolridge Landing, Chattahoochee River.

Pleistocene (first Pleistocene terrace.) 5. Not well exposed, but mostly yellow sand . (Unconformity)
Upper !Cretaceous Ripley formation (Exogyra ponderosa zone). 4. Greenlo~h gray, very glauconitic sand, with some indurated layers . . . . . . . . . . . . . . . . 3. Yellow, laminated, loose sand, and dark drab clay. A layer of decayed shells, among them some large oysters, occurs along the top . . . . . . 2. Dark gray shell marl with gray sand matrix. The most conspicuous fossil, a large undescribed species of oyster. Other fossils are: Trigonia, Oyprimeria densata (Conrad) sharks teeth (numerous), crocodilian teeth, bones, etc. . . 1. Dark gray, argillaceous, micaceous, marine sand, with dark clay streaks . . . . . . . . . . . .

Feet. 15
10 15
3 3

Just below Woolridge Landing, right bank, the bluff reveals strata as described in the following section:

Section below Woolridge Landing) right bank) Chattahoochee River.

Pleistocene (second terrace). 5. Pebbly sand, not well exposed . . . . . . about . Concealed by talus, but probably Cretaceous .
Upper Cretaceous. Ripley formation. (Exogyra ponderosa zone.) 4. Dark gray, compact, argillaceous, finely micaceous, calcareous, glauconitic sand. One small specimen of Exogyra sp. with costae obtained near
base .......... 3. Yellow, rather loose, sandy shell marl with some
dark drab clay laminae. Contains soft shells, including Exogyra, Anomia, Cardium, Trigonia, a large undescribed oyster, etc. Also sharks
teeth, crocodilian teeth and bones . . . . . . 2. Shell marl with gray sand matrix. Shells very
soft. About three feet above base a discontinuous layer of large massive oysters, some specimens of which have a measured length of 17.5 inches . . . . . . . . . . . . . . . . . . . . . 1. Dark gray, micaceous, argillaceous, marine sand .

Feet. 25 15
20
6 5

From the marl, layer No. 2, in the preceding section the following forms were identified:

158

GEOLOGY OF THE COASTAL PLAIN

Chattahoochee River, Woolridge Landing, 461!2 miles below Columbus, 13lj2 miles above Eufaula, in Barbour County, Ala. L. W. Stephenson, collector.

Locality Numbers
~~

Vermes:

Serpula sp.

X

X

Hamulus ?

X

Mollusca:

Nucula percrassa Conrad

X

X

Cucullaea carolinensis (Gabb) .

X

Trigonoarca sp. nov. ( cf. with sp. nov. from Kerrs

Cove, Black River, N. C.) .

X

Breviarca safl'ordi (Gabb) ?

X

X

Nemodon brevifrons Conrad

X

Area sp. ( cf. A. uniopsis Conrad) .

X

Glycymeris sp. ( cf. G. congesta (Conrad) )

X

Glycymeris sp.

X

Inoceramus sp. . . . . . . .

X

Ostrea tecticosta Gabb . . . .

X

Ostrea plumosa Morton . . .

X

Ostrea sp. nov. (very large)

X

X

Exogyra ponderosa var. erraticostata Stephenson .

X

Exogyra sp. (medium sized individual with costae)

X

Trigonia sp. nov. (same as sp. nov. from Snow Hill,

N.C.) ......... .

X

Pecten burlingtonensis Gabb ?

g

Pecten sp. ? . . . . . . .

X

Plicatula sp. . . . . . . .

X

Anomia lintea Conrad . .

X

Venlella conrad! (Morton)

X

Crassatellites sp. nov. . .

X

X

Crassatellites sp. ( cf. C. carolinensis Conrad)

X

Lucina glebula Conrad . . . . . .

X

Cardium eufaulense Conrad ...

X

Isocardia clifl'woodensis Weller ?

X

Cyprimeria depressa Conrad . .

X

X

Aphrodina regia Conrad . . . .

X

Cyclothyris alta Conrad . . . .

X

Legumen planulatum (Conrad)

X

Baroda carolinensis Conrad .

X

Cymbophora lintea (Conrad)

X

Corbula carolinensis Conrad

. . . .. . . . X

X

Gyrodes crenata Conrad . . . . . . . . . . . . . . . .

X

Pugnellus densatus Conrad .

X

Undetermined gastropods . . .

X

Vertebrata: Lamna texana Roemer . . . Corax falcatus Agassiz ..... . Otodus sp. . . . . . . . . . . .

x?

X

x?

X

x?

X

Ischyrhiza mira Leidy (identified by J. W. Gidley) . X

Thecachampsa rugosa Emmons (identified by C. W

G1.more) . . . . . . . . . . . . . . . . . . . . X

Polydectes biturgidus Cope (identified by C. W. Gil

more

X

\
\
\

RIPLEY FORMATION

159

_ .At "Roanoke_ Island," a sho:t distance below \Yoolridge Landing, Uapt. J. W. Smgleton, Supermtendent, U. S. Engineers, obtained from dredged materials the Yertebrate remains listed below. The island referred to no longer exists, having been destroyed by riYet" currents.

Chattahoochee River, bellceen Upper and Lower Roods Bend, and just above mouth of Soapstone Creek. Capt. J. W. Singleton, collr;ctor. Identified by C. W. Gilmore.

Various fragments of the turtle, Taphrosphys ( ?) Fragment of dinosaur limb bone Vertebra of mosasauroid reptile Tooth of large crocodilian, probably Polydectes Coprolites

One mile below \Vcolridge Landing at Lower Roods Bend, the following section is well exposed :

Section at Lower Roods Bend, 47 1/2 miles below Columbus, .12 1/2 miles above Eufaula, left bank.

Pleistocene (terrace deposit). 3. Unconsolidated, yellowish sand, loamy in upper part and with a band of pebbles and cobbles along the base . . . . . . . . . . . . . . . . . (Unconformity)
Upper Cretaceous.
Ripley formation. (Exogyra ponderosa zone.) 2. Dark gray, massive, marine sand. One specimen full of soft shells. Same as marl, layer No. 3 of Gryphaea vestcularis Lamarck obtained . . 1. Dark gray, micaceous, argillaceous, sandy marl fult of soft shells. Same as marl, layer No. 2 at Woolridge Landing section . . . . . . . .

Feet. 25
20 10

From the marl at the base of the preceding section, layer No. 1, the following species were recognized :

Locality No. 6401.-Chattahoochee River, left bank, Roods Lower
Bend, just below the mouth of Soapstone Creek, 121j2 miles above Eufaula, Stewart County, Ga. L. W. Stephenson, collector.
Molluca: Nucula percrassa Conrad Leda sp. Trigonoarca sp. nov. (large) Glycymeris sp. Ostrea plumosa Morton Ostrea sp. nov. (large) Trigonia sp. nov. (same as sp. nov. from Snow Hill, N. C.) Pecten sp. nov. (same as species from Snow Hill N. C.) Anomia argentaria Morton Crassatellites pteropsis Conrad? Cardium eufaulense Conrad

160

GEOLOGY OF THE COASTAL PLAIN

Aphrodina regia Conrad Cyclothyris alta Conrad Lepto:solen biplicata Conrad Corbula carolinensis Conrad Vertebrata:
Lamna tex~na Roemer Corax falcatus Agassiz Otodus ?

About three-quarters of a mile below Lower Roods Bend, the top

)f the marl bed just described is seen to pass finally beneath water

level.

.

Along the outside of the broad bend on the Georgia side of the river

between 48 and 49 miles below Columbus, a bluff presents a nearly

vertical wall, 40 or 50 feet in height, of dark green, compact, argil-

laceous, marine sand. Although no fossils were obtained from them,

these beds are tentatively regarded as forming the upper part of the

Exogyra ponderosa zone of the Ripley formation. The top of this

zone is believed to pass beneath water level between this bend and the

mouth of Cowikee Creek, the materials exposed on this creek, a short

distance above the mouth, being regarded as forming the base of the

overlying Exogyra costata zone.



Northeast of Chattahoochee River (typical marine beds).-The upper part of the section near Jamestown postoffice in Chattahoochee County, 18 miles south of Columbus, Ga. (see section on p. 138 of this report), including layers Nos. 6 to 12 inclusive, is probably referable to the lower part of the Ripley formation. In stratigraphic position these beds are believed to correspond approximately to lay!3r No. 3 of the section at Blufftown on Chattahoochee River (see p. 134 of this report.) This is the farthest point to the northeastward that basal marine beds of the formation have been traced in Georgia. Beyond this point the basal beds appear to merge rapidly into materials of the Cusseta sand type.
:fifarine beds overlying the Cusseta sand member, and probably occupying positions near the top of the zone of Exogyra ponderosa, have been examined at several places northeast of the river as follows:
In a cut of the Seaboard Air Line Railway at Manta (Hichitee P. 0.) in Chattahoochee County, weathered, marine materials make up the upper seven feet of the beds exposed and similar materials are poorly exposed on the hill-slope south of the cut, the whole totaling a thickness of about 27 feet. Although no fossils were found in these materials they are thought to belong to the upper part of the zone in question (see section, p. 162.)
Four miles northeast of Buena Vista on the road leading to Taze-
well, where it ascends the southward-facing slope of Richland Creek

GEOLOGY OF THE COASTAL PLAIN OF GEORGIA.

I:'Ld'l'E XIV.

EXPOS RE IN GULLY IN BUENA VISTA-TAZEWELL ROAD, SIX MILES NORTHEAST OF BUE A VISTA, MARION COUN'.rY, GA.. SHOWING LEAF-BEARING CLAY LENS IN CUSSETA SAND MEMBER Otr THE RIPLEY FORMATJQ::-;.

B. . "SAND STREAM," ONE MILE NORTH OF TAZEWELL. MARION COUNTY, GA., THE AND HA BEEN TRANSPORTED BY TORRENTS FR0:\<1 GULLIES I::-< THE CUSSETA SAND i\1E)1BER

RIPLEY FORMATION

161

Yalley, there is in the road ditch near t~1e base of the hi~l an exposure of 1~ or 15 feet of dark g:ay, fine, arglll~ceous, marine sand bearing fossil casts. On the basis of the contamed fossils this horizon is
correlated approximately with the marl beds exposed at the bases of
the bluffs on Roods Bend, Chattahoochee River (see pp. 135, 136 of. this report.) The following forms \vere recognized:.
Locality No. 5381.-Buena VistacTazewell road, about four miles
northeast of Buena Vista, Ga., on southward-facin,q slope of Richland Creek Valley. (All casts.) L. W. Stephenson, collector.
Vermes: Serpula sp.
Mollusca: Exogyra sp. (cast of young with costae) Ostrea sp. (large cast probably same as sp. nov. from Woolridge Landing.) Pecten quinquenarius Conrad Veniella lineata (Shumard) ? Crassatellites sp. (same as sp. nov. from Woolridge Landing, Chattahoochee River.) Cyprimeria densata Conrad Cyprimeria depressa Conrad Cyclothyris ? Aphrodina sp.

A section on the Buena Vista-Tazewell road six miles northeast of Buena Vista has already been given on page 139 of this report. The upper 70 feet of the section, consisting of weathered, brownish, marine sand, is believed to fall Writhin the upper part of the zone of Exogyra ponderosa. This sand rests upon the coarse, unconsolidated sands of the Cusseta sand member of the Ripley formation. The contact separating the two kinds of materials is somewhat obscured by weathering process and by surface creep, but the relation appears to be that of conformity.
Region between Chattahoochee and Ocmulgee rivers (Cusseta sand member).-From Chattahoochee River northeastward in Georgia, the basal portion of the Ripley formation loses its deeper marine character, being replaced by unconsolidated, coarser, more irregularly bedded sands and clays of shalbw marine or estuarine origin. These near-shore deposits have been designated by Veatch' the Cusseta sand, from Cusseta, Chattahoochee County, in the vicinity of. which they are typically developed.
The materials referred to this member first make their appearance in the high bluff at Blufftown on Chattahoochee River, a section of w:hich is given on page 134 of this report. The upper 100 feet of this section (layer No. 4) is thus referred.
'ClaY, Report: Geol. Survey of Ga., Bull . .!'l<o. 18. )flO!!, p. 88.

162

GEOLOGY OF THE COASTAL PLAIN

Exposures of the beds between Cusseta and :Manta, a distance of five and one-hal miles, in what must be considered the type region, are described below:
A shallow cut of the Seaboard Air Line Railway, in front of the court house at Cusseta, reveals five feet of loose, gray, sha,rp, rather coarse sand, grading down into compact, reddish sand of the same character, the latter about five feet in thickness. The gray sand is believed to have been derived from the underlying red sand by leaching.
A number of cuts 10 to 15 feet in depth, eastward from Cusseta for a distance of two and three-quarter miles, exhibits sections essentially the same as the preceding, the gray surface sands varying in depth from four to eight feet.
Three miles east of Cusseta, at milepost 22 (from Columbus), a 12-foot cut reveals reddish, mottled, coarse, ferruginous, argillaceous sand reaching a maximum thickness of 10 feet, overlying conformably undulating laminated drab clay and red ferruginous sand beds. The undulations in the stratification lines show differences of level of seven or eight feet in a horizontal distance of 40 or 50 feet. (See plate XIII, B.)
Four miles east of Cusseta the railroad crosses a gully which runs from south to north, at the head of which the following succession of beds is exposed :

Section in gully four miles east of Cusseta, Ga., near Seaboard Air Line Railway track.

Upper Cretaceous.

Feet.

Ripley formation (Cusseta sand member).

5. Loose, gray, coarse sand . . . . . . . . . . . . . . . . . . . . . . 4

4. Ferruginous, coarse, massive sand weathered to a rather

even, pinkish red color . . . . . . . . . . . . . . . . . . . . . . . 15

3. Laminated, drab clay and red, ferruginous sand . . . . . . . 3

2. Drab, stratified clay with streaks of yellow. This is a lens

and is replaced horizontally by sand . . . . . . . . . . . . . . . 4

1. White, yellow, and red, fine to medium-grained, slightly

micaceous, crossbedded sand, with scattered drab clay

laminae . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Immediately west of the station at J\Ianta (Hichitee P. 0.) the following section is exposed in a cut:

Section in cut of Seaboard Air Dine Railv:ay at Manta Station ( Hichitee P. 0.), five and one-half miles east of Cusseta, Ga.

Upper Cretaceous.

,

Ripley formation (Exogyra ponderosa zone).

(Typical marine sand.)

Feet.

5. Weathered, coarse. red, ferruginous, compact, massive sand. 7

(Cusseta sand member.)

RIPLEY FORMATION

163

1. Laminated, drab clay, and red and gray, micaceous sand . . 5 3. Gray, medium to coarse, micaceous sand with scattered drab
clay balls, the whole mottled with purple . . . . . . . . . . 7 2. Laminated, drab clay, streaked with yellow . . . . . . . . . . 4 1. Medium to very coarse, gray sand, tinted with pink, and
locally indurated to a purple ferruginous sandstone . . . . . 11

The relation of the Cusseta sand member to the superincumbent typical marinE:) beds as revealed in the cut, is one of conformity, sedimentation having been continuous from the one to the other.
In Marion County the Cusseta sand member outcrops in a belt extending in a northeast-southwest direction, having a width of perhaps four miles on the western border, and eight or ten miles on the eastern border of the county. The materials seem to consist almost entirely of unconsolidated sands with subordinate clay lenses.
The following section was made along the road leading from Buena Vista to Tazewell, about six miles northeast of the former place:

Section along Buena Vista-Tazewell road, six miles northeast of Buena Vista.

Upper Cretaceous.

Ripley formation (Exogyra ponderosa zone.)

(Typical marine beds.)

Feet.

2. Brownish marine 'sand (weathered), about . . . . . . .

70

(Cusseta sand member.)

1. Coarse, light-colored, crossbedded, arkosic sand, locally fer-

ruginous with iron concretions, with white to black clay

lenses. The clay lenses are local in character giving place in

a short distance to sand. The maximum thickness of clay

observed is 12 feet. In a lens of black clay near the base

fossil leaves were collectecl . . . . . . . . . . . . . . . . . . 50

The leaf-bearing lens o black clay, described in the preceding section, has a thickness of four or five feet (see plate XIV, A.). Tlle leaf remains are scattered somewhat sparingly through the clay. E. W. Berry, to whom the plants were submitted, recognized the following species: (See a18o Bn11. Torrey Botan. Club No. 37, 1910, p. 505.)

Andromeda. novae-caesareae Hollick Araucaria bladenensis Berry Doryanthophyllum cretaceum Berry Eucalyptus angusta Velen. Ficus sp. nov.
Manihotoides sp. nov. (same as at McBride Ford) Monocotyledon, gen. et sp. nov. (common to the Black Creek and Tuscaloosa formations)

In the vicinity of Tazewell the surface materials consist principally of coarse, loose sands apparently derived by weathering from

164

GEOLOGY OF THE O~ASTAL PLAIN

the Cusseta sand member. These surface sands are easily transported, and at times of heavy precipitation have been washed down into the small headwater branches forming so-called "sand-streams." (See plate XIV, B.)
The following is the log of a well owned by B. F. Duke, eight miles northeast of Buena Vista, Ga. The owner is authority for the lithology:
Log of well on property of B. F. Duke, eight miles northeast of Buena Vista, Ga.

Upper Cretaceous. Ripley formation (Cusseta sand member). 4. Very hard clay . . . . . . 3. Yellow sand . . . . . . . . . . . 2. "Chalk" (clay) . . . . . . . . . . 1. Yellow sand, water-bearing . . . .

Feet. 0 to 12 12 " 92 . 92 " 104 . 104 " 140

The Cusseta sand member is present i:u a small area in the north-

ern part of Schley County, but the available data are meager. The

same division furnishes the surface materials over about the south-

ern two-fifths of Taylor County. Concerning the character of the

materials Veatch says: (Clay report, p. 224.)

The sand in the southern part of the county contains noticeably more iron and the clay beds are thinner and less pure. A characteristic feature is thin crusts of layers, a few inches thick, and large, hollow nodules of siliceous limonite; the latter are ~oo abundant in some localities that they may be
of some value in the future as a source of iron.

The logs of three wells in this county ~vhich are believed to penetrate strata of this division are given below:

Log of well owned by J. L. Whitley, one and one-half miles north of Mauk, Ga. (Mouth of well level with the track of the Atlanta, Birmingham & Atlantic Railroad.) Authority for lithology, the owner.

Ripley formation (Cusseta sand member).

Feet.

7. Sand

0 to 8

6. Clay

8 " 13

5. Sand .

13 " 38

4. ''Chalk" (clay)

38 " 42

3. Sand .

42 " 60

Eutaw formation ?

2. Black marly "chalk" (clay) . . . . . . . . .

60 " 73

1. "Chalk" (clay) and sand, waterbearing in basal two

feet . . . . . . . . . . . . . . . . . . . . . 73 " 125

RIPLEY FORMATION

165

Log of well owned by G~orge Ruffin, one and one-half miles east of Mauk, Ga. Authority for lithology, J. A. Steed, Mauk, Ga.

Upper Cretaceous. Ripley formation (Cusseta sand member). 5. Clay . . . . . . . . . . . 4. Sand . . . . . . . . . . 3. "Chalk" (clay) and sand 2. Coarse sand . . . . 1. White pebble rock . . .

Feet. ? ? ? ? ?

Total ..... '. . . . . . . . . . . . . . .

0



0

0 0

0

0

90

Log of well three-eighths of a mile north of Southland, Ga., owned by W. G. Hill. Authority for lithology, owner. (Mouth of well about 60 feet above track at station.)

Upper Cretaceous. Ripley formation (Cusseta sand member). 3. Sand . . . . . . . . . . . . . . . . . . . . . . . 2. "Chalk" (white clay) and clay . . . . . . . . . . 1. Fine sand of various colors, water-bearing in lower two feet . . . . . . . . . . . . . . . . . . . .

Feet. 0 to 3 3 to 12
12 to 75

Strata belonging to the Cusseta sand member underlie the northern part of Macon County in an area embracing about one-third of the county. In a gully in the high scarp facing Flint River, five or six miles west of Marshallville, Ga., over 100 feet of materials are exposed, consisting of coarse to fine, more or less arkosic, crossbedded sand with occasional lenses of light drab clay. The sand contains small clay balls in places. About half way to the top of the section an indurated ironstone forms a projecting ledge, and just below this is a layer of large, mechanically included, clay balls. The sands above the indurated layer are more argillaceous than those below it. This whole section is believed referable to the Cusseta member.
At Underwood Ferry, Flint River, one and one-half miles below the locality described, weathered marine sand, poorly exposed about 10 feet above water level, contains soft cas.ts of Venericardia planicosta. It is therefore of Eocene age. If the materials in the gully just described, one and one-half miles north of this place, are of Cretaceous age, as interpreted, there must be a profound unconformity separating the Cretaceous and Eocene deposits, for the difference in level between the Underwood Ferry exposure and the top of the section in the gully must be fully 150 feet. The fossilbearing sand at Underwood Ferry, however, is poorly exposed, and there is a possibility of its having slipped down from a higher level.
There are exposures of coarse sands and light colored clays at a water mill about three miles south of Reynolds, Ga., which are believed referable to this division.

166

GEOLOGY OF THE COASTAL PLAIN

About six miles north of Marshallville the following section 1s exposed in gullies on the west side of the. road:

Section about six miles north of Marshallville, on road farthest west leading from Marshallville to Everetts Station.

Upper Cretaceous. Ripley formation (Cusseta sand member).
4. Deep red ferruginous sand . . . . . . . . . . . 3. Coarse to fine, crossbedded, loose sand with thin
iron crusts, occasional thin clay laminae, and in places scattered, small clay balls . . . . . 2. Bed of purple, massive clay forming a fairly persistent layer . . . . . . . . .... ~ . . . . . . . . . 1. Loose, coarse, crossbedded sand with thin clay laminae which are especially numerous in the upper portion . . . . . . . . . . . . . . . . .

Feet. 10 to 15
30 5 to 6
15

One-half mile farther north on the same road a gully on the west side, furnishes the following section :

Section on road farthest west leading from Marshallville to Everetts Station, six and one-half miles north of Marshallville.

Upper Cretaceous. Ripley formation (Cusseta sand member). 2. Coarse, red, ferruginous sand, with scattered, small quartz pebbl\)s. Appears to grade down through a mottled band into the underlying material . . . . . . . . . . . . . . . . . 1. Fine, yellow, massive, micaceous, somewhat argil-
laceous, fairly compact sand . . . . . . . . .

Feet.
15 20

The red sands in the upper parts of the two preceding section!:\ resemble closely the ferruginous sand formation of supposed Eocene age exposed in cuts in the vicinity of Fort Valley and at Zenith, and they may represent that formation, although no evidence of an unconformity separating them from the underlying materials was observed at these localities.
The following statements concerning the occurrence of Cretaceous strata in this county are quoted from Veatch's clay report:

"In the northern half of Macon County, there is a belt of Upper Creta-

ceous sands in which pockets and beds of white clay have been found. At

no place where these have been examined, do they approach in purity and

thickness the clay loosa] east of the

beds of the Ocmulgee R

Tusca iver.

loo

sa*[Low*er

Cretaceous,
*

but

not

Tusca-

"Some white-stained clay was noted on the west side of Flint River, north

of Oglethorpe. A clay bed is exposed in the cut of the Atlanta, Birmingham

& Atlantic Railroad, near Maverick, and a bed may be seen in the public road

about three-quarters of a mile west of Maverick, adjoining the property of

J. M. Childs. The bed at the latter locality is 8 feet thick; it is white with

purplish and red stains, which seem to penetrate the mass of the clay, and in
places is quite sandy. * * *

"There are a large number of exposures of clay in the red sands west

and northwest of th1s locality; some of tue exposures noted showing a thick-

ness of 15 feet or more, but all were splotched with iron oxide stains."

RIPLEY FORMATION

167

A strip o country, several miles wide, along the
southeastern side o Crawford County, is believed to
all within the Cusseta sand belt. As interpreted,
the member here rests with unconformable relations
upon Lower Cretaceous beds. This conclusion 1s
based upon data obtained rom observations in cuts
o the Southern Railway, just north o Zenith, Ga.
Over a part o the area, the division is overlain un-
conformably by a red, ferruginous sand ormation,
the age o which has not been determined', but which
is probably a northward overlap o one o the Eocene
formations.
The graphic section given in margin shows the re-
lations between the formations exposed in the cuts
near Zenith.
Explanation of Figure. 3. Eocene?-Coarse, deep red, ferruginous
sand, becoming coarser and pebbly in I-wer two feet; the pebbles are of quartz and reach a r_:aximum diamecv::- of two inches. Along the base occurs a line of irregular, partially s.llcified white clay fragments
reaching a maximum diameter a one fovt.
The clay rragments are numerous in places, and elsewhere are scattered: (See plate XVII, A.)
(Unconformity.) 2. Upper Cretaceous.-Ripley formation ( Cus-
seta sand member). An irregularly bedded formation consisting principally of light gray or yellow, fine stratified sand with thin laminae of drab clay and very thin iron crusts; but at intervals there occur lenses of white or yellow sand in places ferruginous; and in places this argillaceous content increases forming thinly laminated clay beds with fine sand partings; one of these clay beds, a in the section, becomes very carbonaceous, being filled with scattered particles and seams of comminuted plant fragments.
(Unconformity.) 1. Lower Cretaceous.-A formation consisting
principally of coarse, gray sands with important clay lenses. The cuts toward the northern end of the section reveat immediately beneath. the contact a bed of massive clay, light in color, but blotched with purple and pink tints.

Logs o two wells southeast of Zenith which penetrate the .Cusseta sand have been obtained. The owners are authority for the lithology.

168

GEOLOGY OF THE COASTAL PLAIN

Log of well on property of J. W. George, one-half mile south of

Leepope, Ga.

Eocene ?
8. Soil . . . . . . . . . . . . . . . . 7. Stiff red clay . . . . . . . . . . . . Upper Cretaceous
Ripley formation (Cusseta sand member). 6. "Chalk" (clay) and gravel . . . . . 5. Coarse sand and gravel, some water . 4. Blue "chalk" (clay) . . . . . . . . 3. Coarse brown sand . . . . . . . . . 2. White and blue sticky "chalk" (clay) 1. Fine sand and gravel, water-bearing .

Feet. 0 to 2 2 to 22
22 to 32 32 to 35 35 to 47 47 to 65 65 to 68 68 to 72

Log of well on property of Isaac Miller, of Fort Yalley, Ga., four
and one-half miles northwest of Fort "Valley, in Crawford County, G(JJ.

Eocene ?
5. Clay . . . . . . . . . . . . . . . . Upper Cretaceous.
Ripley formation (Cusseta sand member). 4. Yellow sand . . . . . . . . . . ... 3. White sand with some purple sand 2. Dark gravel and rocks (pebbles ?)
Lower Cretaceous ?
1. "Chalk" (clay) . . . . . . . . . .

Feet. 0 to 25
25 to 75 75 to 90 90 to 100
100 to 103

. The so-called "chalk" in the above section may correspond to the clay at the base of the section in the railway cuts north of Zenith, Ga. It is therefore tentatively regarded as Lower Cretaceous.
Outcrops of the Cusseta sand member occur in the northern part of Houston County; but over most of the area the beds are concealed by a comparatively thin, ferruginous sand formation, probably of Eocene age, and appear only in stream valleys where erosion has uncovered them, or in artificial cuttings. A good exposure occurs in a cut of the Central of Georgia Railroad, one and one-half miles northeast of Fort Valley. The graphic representation of this occurrence given below is introduced for the purpose of comparison with a similar representation of the occurrences near Zenith, Ga. (See p. 143 of this report.)

sw.

NE.

Fig. 11.-Section in cut of Central of Georgia Railway, one and one-half miles nortnwest of Fort Va,ley, Ga.

RIPLEY FORMATION

169

Explanation of figure. 2. Eocene?-Deep red, massive, coarse, highly ferruginous, more
or less argillaceous sand, much coarser in lower 1 to 2 feet, with scattered quartz pebbles reaching several inches in diameter. Along the immediate base are occasional partially silicified clay balls reaching a maximum diameter of 8 inches, reworked from the underlying beds, and scattered fragments of reworked iron crust.
(Unconformity, obscured in places by weathering.) 1. Upper Cretaceous-Ripley formation (Cusseta sand mem-
ber). Light gray, coarse, argillaceous sand with lenses of coarse sandy, light colored clay, all more or less streaked with yellow and pink. The sand in places contains small pebbles up to one-half inch in diameter.
Layer No. 2 of this section is believed to correspond to layer No.
3 in. the section at Zenith-the red, ferruginous sand of probable
Eocene age being the surface formation over the level stretch of
country extending from Fort Valley to Zenith. Layer No. 1 of
this section corresponds to layer No. 2 of the Zenith section.
About 100 yards northeast of the cut just described, a cut, the
top of which is at a slightly lower level, reveals about 20 feet of
light-colored Cretaceous sands and clays, the lower five feet of
which has a laminated appearance.
At two and one-half miles northeast of Fort Valley on the same
railroad, a cut reveals the following:

Section Central of Georgia Railway, two and one-half miles northeast of Fort T1alley, Ga.

Eocene ?

3. Loose, gray, residual sand . . . . . . . . . . .

2. Mottled, red, highly ferruginous, coarse sand,

fragments of iron crusts in places along base .

Upper Cretaceous.

'

Ripley formation (Cusseta sand member).

1. Light gray, coarse, crossbedded, argiiiaceous sand

and sandy clay . . . . . . . . . . . . . . . .

Feet. 2 5
18

Section in cut six miles northeast of Fort T1alley, Ga.

Eocene ? 2. Coarse, red, ferruginous sand, with a fairly persistent line of pebbles along the base. Fragments of fine, yellow sandstone with a maximum length of 8 inches were observed at one place near the base . . . . . . . . . . . . .
Upper Cretaceous. Ripley formation (Cusseta sand member). 1. Coarse, yellow and red, somewhat ferruginous sand, with thin lenses and layers of drab, sandy clay, and in places lines of small white clay balls . . . . . . . . . . . . . . . . . . . . . .

Feet. 8 8

One-half mile northeast of the station at Byron a section is revealed in a cut, as described below:

170

GEOLOGY OF THE COASTAL PLAIN

Section in cut one-half mile northeast of the station at Byron, Ga.

Eocene ?

Feet. In.

6. Loose, gray, residual sand . . . . . . . . . .

1

5. Weathered, yellow, ferruginous sand, with small,

round, iron concretions. Grades down into next

layer . . . . . . . . . . . . . . . . . . . . .

3

4. Weathered, mottled yellow and red, massive,

rather coarse, argillaceous, ferruginous sand .

6

3. Sharply defined layer of mottled drab and yellow-

ish, finely arenaceous clay . . . . . . . . . . . 2 6

2. Pinkish tinted, massive, loose sand, fine at top,

becoming coarser to very coarse at base. In

lower 1 to 2 feet contains numerous, small, an-

gular, quartz pebbles reaching one inch in diam-

eter, and scattered, angular white clay masses

reaching several inches in diameter . . .

6

(Unconformity, somewhat obscured in places by

weathering.)

Upper Cretaceous.

Ripley formation (Cusseta sand member).

1. Coarse, white or light gray, crossbedded, arkosic

sand, with subordinate white clay lenses . . .

12

One-half mile northeast of th'e preceding, a cut reveals six feet of weathered, mottled, red ferruginous sand, with pebbles and clay balls along the base, resting unconformably upon coarse, crossbedded sand. The former corresponds to layer No. 2 and the latter to layer No. 1 in the preceding section.
The red, ferruginous materials overlying the Cusseta sand at all the localities between Fort Valley and this point described on preceding pages, are believed to be of Eocene age, as they are separated .from the Cretaceous by an unconformity. The unconformable relation of the two is not everywhere directly apparent, due to the weathering effects resulting from the close proximity of the contact to the surface.
One and one-hal miles northeast of Byron a cut reveals materials as graphically represented below:

fm.

Fig. 12.-Section in cut of Central of Georgia Railway one and one-half

miles northeast of Byron, Ga.

'

Explanation of Figure.
Upper Cretaceous. Ripley formation (Cusseta sand member). 2. Light, gray, coarse, rather loose, crossbedded sand streaked with yellow, with subordinate clay lenses.

RIPLEY FORMATION

171

1. .v'or the most part light to drab clay with subordinate sand layers and lenses, in part laminateu and in part massive. At one place, a in the section, there is about 6 feet of dark drab to chocolate carbonaceous clay filled with comminuted plant particles, which grades laterally into tne lighter clays. The lower part of the dark clay is laminated, with fine sand partings; the upper part is more massive and in this were found a few determinable plant remains.
The plants from layer No. 2 were submitted to E. W. Berry, who furnished the following list: (See also Bull. Torrey Botan. Club No. 37, 1910, p. 505.)
AraJcaria jeffreyi Berry Cunninghamites elegans (Corda) Endl. Dryopteris sp. nov.
At mile-post 15 on the Central of Georgia Railway, two miles northeast of Byron, a cut reveals about 50 feet of Cusseta materials consisting of light gray, coarse to very coarse, arkosic, incoherent sand with subordinate lenses of light drab to white, massive clay reaching several feet iv. thickness. Veatch has described the clay lenses in these sands from the economic standpoint in his clay report, pp. 213-215.
A well owned by J. W. Epting, one and one-quarter miles southwest of Powersville, probably penetrates the strata of this formation. .The log is given below. The owner is authority for the Jithology.

Log of well one and one-quarter miles southwest of Powersville, Ga.

Eocene ?

Feet.

5. Clay . . . . . . . . . . . . . . . . . . . . about 0 to 30

Upper Cretaceous.

Ripley formation (Cusseta sand member).

4. "Chalky" (clayey) strata gradually becoming

sandy, (some water) . . . . . . . . . . about 30 to 60

3. Clay . ; . . . . . . . . . . . . . . . . . . about 60 to 85

2. Sandy "chalky" (clayey) strata, yellowish, about 85 to 108

1. Coarse, white sand, water-bearing . . . . . . . 108 to 110

A well owned by H. C. Harris at Fort Valley, Ga., the log of which is given below, probably penetrates the entire thickness of this formation:

Log of well at Fort Valley, Ga., furnished by the owner.'



Feet.

8. Red clay . . .

20

7. Sand . . . . . . . . . .

20

6. White clay . . . . . . .

8

5. Yellow sand . . . . . .

40

4. White clay . . . . . . .

10

3. Quicksand with pebbles

.

400

2. H~ rd rock . . . . . . . . . . . . . . . Thickness not given ( ?)

1. Quicksand ' . . . . . . . . . . . . . . . ThicknelsSI not given ( ?}

Total. . . . . . . . . . . . . . . . . .
'Quoted from Bull. Geol. Survey of Georgia No. 15, 1908, p. 120.

1075

172

GEOLOGY OF THE COASTAL PLAIN

with the exception of the upper 20 feet, which is probably referable to the Eocene, the beds penetrated in the Fort Valley well are all of Cretaceous age. Doubtless the Cusseta i!and member of the Ripley formation, whi~h immediately underlies the red Eocene stratum at the surface, was entirely penetrated, and the deeply buried, underlying Lower Cretaceous strata entered to a depth of several hundred feet. Indeed, it seems probable, if the depth reached was as great as given, that the bottom of the well was very near the crystalline basement rocks when the drilling was discontinued.
A well at Byron, described below, is believed to have passed through 15 or 20 feet of Eocene strata in its upper part, below which the beds penetrated probably all belong to the Cusseta sand member.

Log' of well at Byron, Ga.

Feet.

Sand and "chalk" (kaolin) ....... . .

0 250

Quicksand and "chalk" (kaolin) in 3-foot layers,

water bearing stratum, coarse sand . . . . . 250 310

It is believed that the Cusseta sand belt extends eastward from Byron through the southern part of Bibb County into the extreme western part of Twiggs County, and somewhere to the west of Bullards passes under the overlying Eocene beds. Little detailed information is available in this region, however, and until such has been obtained the exact limits of the division with respect to the 'underlying Lower Cretaceous beds and the mrerlying Upper Cretaceous (Providence sand) and overlapping Eocene beds, mnst remain indefinite.
The log of one well near 'Valden, in southern Bibb Connty, which penetrates the Cusseta sand member, is given below:

Log of well one and one-half miles west of Walden, Ga., owned by W. G. Middlebrooks. The owner is authority for the lithology.

Upper Cretaceous.

Ripley formation (Cusseta sand member).

Feet.

3. Red clay . . . . . . . . . . . . . . . . . . . . . . . . . . 0 22

2. White sand and kaolin, about . . . . . . . . . . ... 22 70

1. , Clay and sand, water-bearing . . . . . . . . . . . . 70 82

DETAILED SECTIONS (EXOGYRA COSTATA ZONE).
Chattahoochee River (typical marine beds).-In bluffs just belo'v the mouth of Cowikee Creek and in a bluff about 40 feet high on Cowikee Creek, a few hundred yards above its junction with the
1Geol. Surv. of Ga., Bull. No. 15, 1908, p. 122.

RIPLEY FORMATION

173

river, dark gray to almost black, compact, argillaceous, uucaceous, marine sand is well exposed. A few scattered fossils were found here, comprising marine or brackish water shells and plants associated in the same layers. The plant remains bear signs of considerable trituration. They were probably floated into the body of water where deposition was taking place, and becoming water-logged sank and mingled with the shells.
The following are the invertebrates recognized from the locality just described:

Cowikee Creek, Barbour County, Ala'., near mouth. Collectors, T. W. Stanton and L. W. Stephenson.

Mollusca:

Nucula sp. (small) . . . . . . . . . . . . . . . .

X

X

Nucula sp. . . . . . . . . . . . . . , . . . . . . . . . .

X

Ostrea plumosa Morton . . . . . . . . . . . . .

X

Ostrea subspatulata Forbes? (young individual)

X

Cymella bella Conrad . . . . . . . . . .

X

Liopistha sp. . . . . . . . . . . . . . .

,x

Leptosolen sp. . . . . . . . . . . . . . . . ....... . X

The invertebrates at this locality are closely associated with poorly preserved lea remains, of which the following were identified by E. W. Berry:

Bauhinia sp. nov. Platanus sp. nov. Laurus sp.

Salix sp. Sapindus sp. Fern, not determinable.

Opposite the mouth of Burstahatchee Creek, right bank, about five and one-half miles above Eufaula, 15 or 20 feet of dark gray, compact, calcareous sand appears above water level. This horizon is well within the Exogyra costata zone. The following fossils were obtained here :
Chattahoochee River, right bank, opposite mouth of Burstahatchee Creek, about five and one-half miles above Eufaula in Barbour County, Ala. T. TV. Stanton and L. W. Stephenson, collectors.

174

GEOLOGY OF THE COASTAL PLAIN

Locality Numbers.

s.\ T. W. L. W. S.

853

6398

Echinodermata:

I \

Hemg:;~ u~g~l~ .(~~rt.o~) ..(I~e.n~i~e~ ~~ .W.. ~j x

? cog~:!o~a .m.o~to.ni. (.d~ ~e~i~l). (.l~e~ti.fi~d .b~ V:. ~ \ x 1
Mollusca:

inoceramus sp. . . . . . . . . . . . . . . . . . . . . ..

X

Ostrea plumosa Morton . . . . . . . . . . . .

X

Ostrea: larva Lamarck . . . . . . . . . . . . .

x

Ostrea subspatulata Forbes ? (young in.d.)

x

Ostrea sp. . . . . . . . . . . . . . . .

x

Gryphaea vesicularis Lamarck . . . ..

X

Exogyra 'costata Say . . . . . . .

X

Pecten quinquescostatus (Sowerby) . .

x

X

Anomia argentaria Morton . . . . . .

x

X

Paranomia scabra (Morton) . . . . . . . . . . .

x

X

Veniella conradi (Morton) . . . . . . . . . .

j

X

Cardium sp. . . . . . . . . . . . . . . . . . . . ..

X

Scala sillimani (Morton) . . . . . . . ...... : [ x

Turritella trilira Conrad . . . . . . . . . . .

X

Pyropsis sp. . .. . . . . . . . . . . . . . . . . . ..

X

Arthropoda:

Crab remains . . . . . . . . . . . . . . . . . . . . x

Just below the mouth of Burstahatchee Creek on -the Georgia side the river impinges against the base of a hill having a height above zero water level of 240 or 250 feet. Only about the upper 100 feet of the section is clearly exposed. The following is a description of the strata:

Section at Stewarts Hill, Chattahoochee River, five and one-half miles above Eufaula, Ala.

Upper Cretaceous.

Feet. In.

Ripley formation (Layers 8 to 15 inclusive probably rep-

resent the transition from the typical marine

beds to the Providence sand member.)

15. Coarse, red and yellow, argillaceous sand, well

exposed only in lower 5 feet . . . . . . . . . 10

14. Layer of ironstone averaging 2 inches . . . . . . 0 2

13. Laminated, fine, varicolored, argillaceous, micace-

ous sand, becoming more argillaceous to a clay

at base . . . . . . . . . . . . . . . . . . . . 10

12. Coarse, gray and reddish, argillaceous sand . . . 5

11. Laminated, varicolored, finely arenaceous, micace-

ous clay with pockets and small lenses of coarse

sand ............ 10. Irregular layer of coarse ironstone . . .

4 0 1-5

9. Coarse, rather loose, yellow, arkosic sand

9

-

RIPLEY FORMATION

175

8. Irregular layer of ironstone, averaging . . . . . 0 2

7. Fine, greenish gray, argillaceous, micaceous sand,

finely mottled with yellow . . . . . . . . . . 22

6. Finely laminated sand and clay with thin plates of

ironstone . . . . . .. . . . . . . . . . . . . 3

5. Fine, gray, micaceous sand, deUcately mottled with

purple, red and yellow . . . . . . . . .

20

4. Coarse ironstone . . . . . . . . . . . . . . . . . 0 6

3. Mottled, fine, gray, micaceous sand . . . . . . . 10

2. Gray, micaceous, sand and dark, laminated, mica-

ceous clay, poorly exposed . . . . . . . . about 30

1. Concealed, except masses of dark gray marine

sands and clays at base which are not in place

but have slipped down from a higher level

. . . . . . . . . . . . . . . . . . . . . about 125

Between Stewarts Hill and Eufaula there are numerous bluffs where the river cuts against the edge of the lo~west Pleistocene terrace,

exposing at their base 30 or 40 feet of Ripley strata which are overlain by 10 to 20 feet o Pleistocene terrace sand and clay. The Cre-

taceous materials consist principally of gray, more or less calcareous

and argillaceous, compact, marine sands, some layers of which are indurated, forming projecting ledges along the aces of the bluffs. In places the argillaceous content increases, forming dark, finely

arenaceous clays. The materials are more or less fossiliferous, and

although no collections are now available for study it is doubtless

entirely feasible to make such collections. At St. Francis Bend, tvm and one-hal miles above Eufaula, Ala.,
Capt. J. W. Singleton, Superintendent U. S. Engineers, of Columbus,

Ga., collected a fragment of a dermal scute and the symphysical portion of the lower jaw o a Gavial. These were received by the Na-

tional Museum through Prof. S. W. McCallie, State Geologist o

G-eorgia. They were identified by C. W. Gilmore. At Eufaula there is an excellent exposure of the beds of this di-

vision in the river bluff below the wagon bridge. (See plate XV, B.)

Section at Eufaula, Alabama.
Pleistocene (second terrace deposit above river level). 2. Yellow and red, argillaceous, more or less pebbly
sand . . . . . . . . . . . . . . . . . . . . . . (Unconformity).
Upper Cretaceous. Ripley formation. (Exogyra costata zone.) 1. Dark gray to black, more or less calcareous, micaceous and glauconitic sand and clay, extremely micaceous in some layers, with indurated nodular, ~calcareous layers, 5 to 10 feet
apart. Contains fossils . . . . . . . . . . . .

F'eet. 20
80

This is the type locality for a large number of fossils described by

the early investigators of the CretaQeous deposits of this region. The

following list has been prepared rom the collections of different

workers, made since the year 1890.

176

GEOLOGY OF THE COASTAL PLAIN

Eufaula, Ala. Collectors, W. P. Copeland> L. C. Johnson> T. W. Stanton, L. W. Stephenson.

Locality Numbers

L.c.J.I w.P.c.l T.w.s.l L.w.s.l L.w.s \

186

389

854 5416 64UO

Coelenterata:

Undetermined coral

Echinodermata:

Hemiaster lacunosus Slocum (lden-

ti:fied by W. B. Clark)

Cassidulus micrococcus Gabb

Ident. by W. B. Clark)

Vermes:

Serpula barbata Morton

Hamulus onyx Morton

Mollusca:

Nucula percrassa Conrad

Nucula distorta Gabb ?

Nucula sp.

Leda pinnaforma Gabb

Cucullaea vulgaris Morton (var.)

Breviarca cuneata (Gabb) .

Nemodon eufaulensis Conrad

Glycymeris subaustralis (d'Orbig-

ny)

Gervilliopsis ensiformis Conrad

Inoceramus sp.

Pteria ?

Ostrea larva Lamarck

X

Ostrea tecticosta Gabb.

X

Ostrea subspatulata Forbes

X

Ostrea plumosa Morton Ostrea peculiaris conrad

.: I

Gryphaea vesicularis Lamarck .

X

Exogyra costata Say

X

X

Trigonia eufalensis Gabb

X

Trigonia sp..

Pecten simplicius Conrad

Pecten argillensis Conrad

Pecten tenuitestus Gabb

Pecten sp.

Lima reticulata 1.<1orbes

Anomia argentaria Morton

X

Anomia sp.

Paranomia scabra (Morton)

X

Grenella serica Conrad

I

Dreissensia tippana Conrad

Pholadomya occidentalis Morton . X

Anatimya anteradiata (Conrad) .

Veniella conrad! (Morton)

Vetericardia crenalirata (Conrad).

Crassatellites eufalensis Gabb Crassatellites pteropsis Conrad

I

Tenea pinguis Conrad ?

Sphaerella concentrica Conrad.

Cardium eufaulense Conrad

X

I

I

!
X

X

X
.x

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

x X

X

X

X X

I X

X

X

X

X X X

X

X

I X i

X

I

X

I X

!
I

X

I I

GEOLOGY OF THE COASTAL PLAIN OF GEORGIA.

PJ,ATE XV.

ON MERCERS MILL CREEK, ' EAR GEORGETOWN IN QUITMA r GA., BOWING FOSSILIFEROUS. MARINE A D OF THE
RIPLEY FORMA'riON.

B. BLUFF ON CHATTAHOOCHEE RIVER. AT EU~'AULA, ALA., 'BOWING 0 FEE'.r OF GRAY, CAL ARE US, :llARINE ANDS AND CLAY OF THE RIPLEY FORMATION.

RIPLEY FORMATION

177

Locality Numbers
L.C.J.I w.P.c.l T.w.s.l L.w.s.l L.w.s.l 186 389 B54 5416 6400

Cardium spillmani Conrad

X

Cyprimeria depressa Conrad

X

Cyprimeria alta Conrad

X

Aphrodina tippana (Conrad) Legumen planulatum (Conrad)

X

:X:

X

X

Aenona eufalensis Conrad

X

. . . . . . . Linearia sp. ( cf. L. carolinensis Con.
Linearia sp.

X X

Leptosolen biplicata Conrad

X

X

:X:

Cymbophora lintea (Conrad)

X

Corbula crassiplica Gabb

X

Corbula Teredo

sp(.ot.he.r

.s.pe.ec.ie.s).

.

X

X

X

Dentalium ripleyanum Gabb

X

Lunat~a obliquata M. & H.

X

Turritella vertebroides Morton

X

Turritella trilira Conrad

X

X

. Pterocerella sp.

Anchura sp.

.

.

X
X

Pugnellus densatus Conrad

X

Ringicula pulchella Shumard

X

Nautilus dekayi Morton

X

Baculites sp.

X

Turrilites ?

X

Arthropoda:

Bairdro sp. (Ostracoda indentified

by R. S. Bassler)

X

Crab remains

X

X

I

I

I

Prof. Eugene A. Smith' has published the log of a well located at

Eufaula which throws light on the character of the materials beneath water level at this place. It is quoted as follows:

Record of Eufaula 01z and Gin Company's 1tell, Rufaula.

Feet.

Top soil and sand . . .

0 to 30

Marl . . . . . . . . . .

. 30 " 380

Soft sandstone . . : . .

. :>80 " 381

Cavity with a little water

. 381 " 389

Marl, water below in very fine sand .

. 389 " 950

More than half the thickness of strata described in this log doubt-

less belongs to the Ripley formation, but it is probable that several

hundred feet of the underlying Eutaw strata ~were penetrated.

Below Eufaula, typical beds of the formation are exposed in JJ\1-

merous bluffs. The fossils listed below were collected by Dr. T. W. Stanton at a point two miles below the landing at Enf~ula.

1Geoi. Surv. of Alabama. The Underground Water Resources of Alabama, Mont gomery, 1907, p. 240-241.

178

GEOLOGY OP THE COASTAL PLAIN

Localif.u So. iY!/. Clwtfaltoochee R1:cer, bettceen Eufaula and Barbour C'1C!'k. T. 1\'. Stanton> collector.

1\Iollusca:
Nucula eufalensis Gabb Nucula perc:rassa Conrad ::'>!ucula cuneifrons Conrad Leda pinnaforma Gabb Ledo longifrons Conrad Cucullaea sp. Breviarca cuneata (Gabb) Nemodon eufalensis Conrad Glycymeris subaustralis (d'Or-
bigny)
Glycymeris subaustralis (d'Orbigny) (var. ?)
Glycymeris sp. ? Gervilliopsis ensiformis (Con-
rad)
Perna sp. Exogyra costata Say
Gryphaea vesicularis Lamarck (small)
Trigonia eufalensis Gabo Pecten argillensis Conrad Pecten simplicius Conrad Pecten quinquenarius Conrad Lima ac:utilineata (Conrad) Lima reticulata Forbes Lima pelagica (Morton)
Anemia argentaria Nlorton Anomia sp. Pul\inites argentea Conrad Crenella serica Conrad Arthropoda:
Crab remains

Dreissensia tippana Conrad Cuspidaria ventricosa Meek & Hay-
den Liopistha protexta Conrad Veniella conradi (Morton)
Vetericardia crenalirata Conrad Crassatellites eufalensis Gabb Crassatellites pteropsis Conrad Crassatellites sp. Cardium l'iimmeli Weller Cardium eufaulense Conrad Cyprimeria alta Conrad (var. ?) Linearia metastriata Conrad Linearia (other species)
Corbula crassiplica Gabb Corbula (several other species) Undetermined pelecypods Gastrochaena americana Gabb Dentalium ri11leyanum Gabb Dentalium sp. Cadulus obnutus (Conrad) Lunatia obliquata M. & H. Turritella trilira Conrad Turritella vertebroides Morton Turritella (other species) Fusns sp. Volutomorpha dumanensis Dall ::Vlorea cancellaria Conrad ~Undetermined gastro11ods Turrilites alternatus Tuomey

One mile below the month of J3arbour Creek on the Georgia side of the riYer, eight or ten feet of gray, 1narine sand with indurated ledges is exposed. The materials above mw of the~e ledges, six or seven feet above low water, have been washed away over a considerable area by the high waters, forming a shPlf. I~arge numbers of specimens of BJ;ogyra costafa Say and Grypha'a Lamarck, washed from the Cretaceon~ materials, haYe accnmn1ated in the shallo\\' basins on this shelf.
Eight miles below Eufaula, near Alexanders Landing, on the Alabama side, materials outcrop as described in the following section:

Section> Chattahoochee River, rilexanders Landing, eight miles beloll'

Eufaula, Ala, right bank.

Pleistocene (terrace deposit) 3. Slope covered with vegetation except a gravel
band along base . . . . . . (Unconformity.)

Feet. 20 or 30

Upper Cretaceous. Ripley formation. (Exogyra costata zone).

RIPLEY FORMATION

179

2. Coarsely arenaceous limestone with numerous

specimens of Echinodermata. One specimen of

Ostrea subspatulata Forbes (variety) also ob-

tained . . . . . . . . . . . . . . . . . . . . .

15

1. Dark gray, more or less argillaceous, very micace-

ous marine sand . . . . . . . . . . . . . . . .

15

Prof. \Ym. B. Clark, to whom the specimens were submitted, identified the following species of Echinodermata from layer X o. 2 of the preceding section:
Cassidulus porrectus Clark Cassidulus subconicus Clark Cassidulus subquadratus Conrad

\\'hen this locality was visited by Dr. t-ltanton there was ex]JO>Oed, wmcwlwre near Alexander's Landing, above layer No. 2 .of the preecding seetion, a bed, eonsisting 'of unconsolidated marine material from \Yhich Dr. Stanton collected the following species:

Locality "-Vo. 8B6.-Chattahoocl1ee River, Alexanders Landing, eight miles be~oll' Eufaula, Ala. Collector, T. \\'. Stanton.

Mollusca: ~ucula percrassa Conrad Nucula distorta Gabb ? Nucula sp.
Leda pinnaforma Gab Leda sp. cf. L. marlboroensis
Weller Cueullaea antrosa Morton Breviarca cuneata (Gabb)
Nemodon eufalensis Conrad Glycymeris subaustralis (d'Or-
bigny)
Pecten argillensis Conrad Pecten simplicius Conrad Anomia linifera Conrad Anomia sp. nov. (same as "Nar-
rows" of Pataula Creek) Dreissensia tippana Conrad

Pholadomya occiden talis Morton Pholadompa sp. nov. (same as at
"Narrows" of Pataula Creek)
Liouistha protexta Conrad Crassatellites pteropsis Conrad Cyprimeria depressa Conrad Linearia ? Aenona eufalensis Conrad Cymbophora lintea Conrad ? Corbula ( several species)
Lunatia obliquata Meek & Heyden Gyrodes sp. Undetermined pelecypods and gastro-
pods Hamites sp. nov. (same as at Prairie
Bluff, Ark., etc.)

Arthropoda: Crab claw
Vertebrata: Undetermined tooth of fish.

Two miles below the preceding, about 10 miles below Eufaula, 25 or 30 feet of similar echinoid bearing rock with interbedded soft sand pockets and layers, appears in a bluff on the Georgia side of the river. The same species of Echinodermata were obtained here, also Ostrea subspatulata Forbes (variety) and Caadium kummeli Weller.
At the mouth of Pataula Creek, 12% miles below Eufaula, Doctor Stanton collected the following fossils from typical marine materials:

180

GEOLOGY OF THE COASTAL PLAIN

Locality No. 855.-Chattahoochee River at mouth of Pataula Creek, Ga. T. W. Stanton, collector.

Mollusca: Nucula percrassa Conrad Nucula distorta Gabb ? Nucula eufalensis Gabb Leda pinnaforma Gabb Leda longifrons Conrad Le'da sp. (cf. L. marlboroensis Weller) Perrisonota protexta Conrad Cucullaea littlei (Gabb) Breviarca cuneata (Gabb)
Nemodon eufalensis Conrad Glycymeris subaustralis (d'Or-
bigny)
Glycymeris ? Gervilliopsis ensilformis (Con-
rad) Gervilliopsis sp. Gryphaea vesicularis Lamarck Trig'lnia eufalensis Gabb Pecten argillensis Conrad Pecten argillensis Conrad Pecten simplicius Conrad Pecten tenuitestus Gabb Lima acutilineata (Conrad) Lima reticulata Forbes Anomia argentaria .Morton Anomia sp. nov. (same as at
"Narrows" of Pataula Creek) Pulvinites argentea Conrad Crenella serica Conrad Dreissensia tippana Conrad Pholadomya sp. nov. (same as

at "Narrows" of Pataula Creek) Liopistha protexta Conrad Veniella conradi (Morton) Etea carolinensis Conrad Vetericardia crenalirata (Conrad) Crassatellites pteropsis Conrad
Crassatellites eufalensis Gabb Crassatelhtes sp. Tenea pinguis (Conrad) ? Sphaerella concentrica Conraa Cardium eufaulense Conrad Cardium spillmani Conrad Cyprimeria alta Conrad (var. ?) Cyprimeria depressa Conrad Legumen planutatum (Conrad) Aphrodina tippana Conrad Aenona eufalensis Conrad Linearia metastriata Conrad Linearia sp. Leptosolen biplicata Conrad Cymbophora lintea (Conrad) Corbula crassiplica Gabb Corbula (several other species)
Dentalium ripleyanum Gabb Pleurotomaria ? Lunatia obliquata Meek & Hayden Turritella sp. nov. (with two spiral
ribs)
Turritella sp. Sphenodiscus pleuriseptus (Conrad) Undetermined pelecypods and gas-
tropods

Vertebrata: Dermal scute of gavial-like crocodile

(Identified by C. W. Gilmore.)

One mile below the mouth of Patan1a Creek Dr. Stanton collectrd the following fossils:

Locality No. 859.-Chattahoochee River, one mile below the mouth of Pataula Creelc. T. W. Stanton, collector.

Mollusca:

"Narrows" of Pataula Creek.)

Cucullaea littlei (Gabb)

Crassatellites sp.

Glycymeris subaustralis ( d'Or- Cardium spillmani Conrad

bigny)

Cardium eufalensis Conrad

Exogyra costata Say

'Cardium tippanum Conrad

Trigonia angulicostata Gabb

Aphrodina tippana Conrad ?

Pholadomya sp. nov. (same as at

Thirteen and one-haH miles below Eufaula, and one and one-half miles above Othos Landing, on the Alabama side, the foUowing section occurs :

RIPLEY FORMATION

181

Section 13 1/2 miles below Eufaula, and one and one-half miles above Othos Landing, right bank.

Tree-covered slope probably in part Eocene . . . . . Upper Cretaceous.
Ripley formation. (Exogyra costata zone) 2. Gray, coarsely arenaceous clay, with poor fossils, Anomia argentaria Morton recognized.. Brown-
ish band a few inches thick along base . . . . 1. Gray marine sand alternating with numerous
ledges of coarsely arenaceous limestone. Contains Oassidulus subquadratus Conrad, Exogyra costata Say, Cardium kiimmeli Weller, and undetermined gastropods, about . . . . . . . . .

Feet. 50 3 25

Between the preceding locality and Morris Landing, 15 miles below Eufaula, indurated ledges were seen at intervals .projecting from bluffs partially overgrown with vegetation, but no detailed observations were made until Morris Landing was reached. Somewhere in this distance the Cretaceous beds have passed finally beneath water level, for at J\forris Landing only Eocene rock is exposed. The basal three feet here consists of partially indurated, calcareous, argillaceous sandstone containing numerous casts of Turritella mortoni Conrad and some other Eocene fossils. This is overlain by coarse, sandy limestone, which grades upward into white limestone, containing but little sand, the whole thickness amounting to about 20 feet.

Region between Chattahoochee and Ocmulgee 1ivers (typical marine beds).-Typical marine beds of the Ripley formation, referable to the zone of Exogyra costata, appear at the surface in a belt which extends from Chattahoochee River to the northeastward, including parts of Clay, Quitman, Stewart, Chattahoochee, Marion, Schley, and ~Iacon counties. From Quitman County, so1).theast of Georgetown, to the northeastern extremity of their occurrence in Macon County, the beds are overlain by the Providence sand member of the formation.
Fossiliferous exposures have been studied at several localities in Quitman County. At the bridge of the Central of Georgia Railway over Mercers Mill Creek, one-half mile south of the station at Georgetown, there is exposed eight or ten feet of dark gray to black, finely arenaceous, micaceous sand containing bits of lignite and many fossils. (See plate XV, A, opposite p. 176.) Many of the species oc curring here are small forms. They are for the most part pelecypods and gastropods. The following forms have been identified:

182

GEOLOGY OP THE COASTAL PLAIN

Locality No. i5417.-1viercers Mill Creek, CcHtml of Georyia Railway
bridge, near Georgetown, Ga. L. lr. ~'J'tephenson, collector.

Protozoa:

Nodosaria sp. Coelenterata:
Stephanophyllia (near bowerbankii M. E. & H.) (Identified by T. W. Vaughan)
Vermes: Serpula sp. (long, nearly straight tube) Hamulus onyx Morton

Hamulus squamosus Gabb

Mollusca:

Crassatellites eufalensis Gabb

Nuc1:1la distorta Gabb ?

Scambula perlana Conrad

Nucula sp.

'Lucina sp.

Breviarca cuneata (Gabh) ? Tenea pinguis Oonmd

(young)

Cardium kiimmeli Weller

Leda pinnaform<t Ga.bb

Cardium eufaulense Conrad

Nemodon eufalenss Cor_rad

A;phrodina ti.ppana Conrad

Glycymeris subaustralis (<J.'O r- Aenoma eufalensis Conrad

bigny)

Linearia metastriata Oonrrud

Gervilliopsis cnsiformis (Con- Gymbophora lintea (Conrad)

rad)

Corbula crassiplica Gabb

Inoceramus sp.

Corbula (several other species)

Ostrea sp.

Dentalium ripleyanum Gabb

Gryphaea vesicularis Lamarck? Dentalium sp.

(young)

Cadulus obnutus (Conrad)

Exogyra costata Say

Scala siUimani (Morton)

Trigonia eufalensis Jaoh

Rapana stantoni Weller

Pecten simplicius Conrad

Eulima sp.

Lima acutilineata (Conrad)

Pleurotoma ? melanopsis (Conrad)

Lima reticulata Forbes

Pleurotoma ? laqueata (Conrad)

Anomia argentaria Morton

Lunatia obliqua1Ja Meek and Hayden

Anomia linifera Conrad

Turritella trilira Conrad

Crenella serica Conrad

Strepsidura interrupta Conrad

Dreissensia tippana Conrad

Morea cancellaria, Conrad

Veniella conradi (Morton)

Volutoderma sp.

Vetericardia crenalirata (Con- C'yclichna ?

rad)

Undetermined gastropods

Arthropoda:

Bairdro sp. (ostracod identified by R. S. Bassler)

The horizon exposed at Mercers 1\Iill corresponds in vertieal position to the upper part of the Cretaceous portion of the section in the bluff at Eufaula. The Cretaceous beds at this mill are overlain by Pleistocene terrace gravels as shown by exposures just to the east of the Central of Georgia Railway bridge.
On the Georgetown-Coffinton roa<.l, about six miles south of Coffinton, just south of a bridge over a small creek, materials are exposed as described in the following section:

Section in Georgetolcn-Coffinton road, six miles south of Coffinton,

Quitman, c.mmty.
Pleistocene ? 2. Yellow sand and loam with small fragments of
limestone along base . . . . . . (Unconformity)

Feet. 15

RIPLEY FORMATION

183

Cpper Cretaceous.

Ripley formation (Exogyra costata zone)

1. Dark gray, marine cl_ay . . . . . . . . . . . . .

5

Fossils were obtained in the marine clay in the precedi11g section

as follows:

L_ocality ~Yo. 5-38J.-Georgeto tcn-U offinlon road', six 111 iles south of Coffinton, Ga., and ju.st south of bridge ocer small cJeel<. L. W. Stephenson, collecfo1.

Vermes: Hamulus onyx Morton
Mollusca: Ostrea larva Lamarck Exogyra costata Say

Anomia argentaria Morton Paranomia scabra (Morton)

The horizon at the preceding locality probably correspond~ approximately to that at Mercers :Mill described above.
In a cut of the Central of Georgia Railway five mile~ southeast of Eufaula, Ala., in Quitman County, Ga., the follmYing section is exposed:

8rction in nd of ('eniral oJ' Grori.r;a Railll'ay, fire miles southeast of Eufa-ula, Ala., in Quitman County, Gn., ncar fhe 1-Wfh milepost.

Upper Cretaceous.

Feet. In.

Ripley formation (Exogyra costata zone).

6. Weathered, rather fine, harsh, micaceous, slightly

argillaceous sand faintly tinted with red and

pink, with iron crusts locally distributed and

with a thin iron crust along base . . . . . . . 10

5. Fine, micaceous sand, similar to preceding, but

looser in texture . . . . . . . . . . . . . . . 2

6

4. Laminated, drab, finely arenaceous and micaceous

clay with fine, micaceous sand partings, iron

crusts along base . . . . . . . . . . . . . . . . o

6

3. Yellow, loose, medium to fine, micaceous sand . . 5

2. Gray, micaceous, argillaceous sand, with some

clay films and occasional thin iron crusts . . 4

1. Light gray, yellowish, coarse, somewhat micaceous

sand, with irregularly developed ferruginous

masses containing prints of fossils. Exposed 5 to 10 feet.

From layer No. 1 in the above section the forms listed below haye been identified:

Locality No. ()[J,n.-One lwndred and thirty-ninth milepost, Central of Georgia Raril1.cay, Qvitman County, Ga. [about five miles southeast of Eufaula, Ala., L. W. 8.]. Collcctor, Otto Veatch.

Mollusca: Pecten sp. Crassatellites pteropsis Conrad Cardium kUmmeli Weller

Cardium eufaulense Conrad ? Cardium tippanum Oonrad Pugnellus sp. Anchura sp.

184

GEOLOGY OP THE COASTAL PLAIN

The horizon from which the above listed forms was obtained is

probably higher stratigraphically than the Mercers Mill exposure,

and not so high as the Pataula Creek exposure described below.

An interesting section is exposed in Clay County at the "Narrows"

of Pataula Creek, nine miles north of Fort Gaines, and two miles

above the mouth of the creek. The so-called "Narrows" is a gorge

about one-eighth mile long, cut in the Ripley formation, the gorge

proper being some eight or ten feet deep and terminating up stream

in a picturesque w~terfall. The section given below was taken near

the head of the gorge and shows the character of the materials in the

gorge proper and in the slope above the level of the brink of the falls.

(See Plate XVI, A and B.)

'

Section near head'of gorge at the "Narrows" of Pataula Creek, nine miles north of Fort Gaines, Clay County, Ga.

Upper Cretaceous. Ripley formation (Exogyra costata zone). 2. Brownish, weathered, argillaceous, marine sand . 1. Dark greenish gray, massive, micaceous, argillaceous, marine sand with indurated ledges 1 to 6 ft. apart. A few specimens of Exogyra cos-
tata Say observed, and near the base an abundance of decayed shells . . . . . . . . . . . .

Feet. 12
23

Just below the mouth of the gorge, in a horizon slightly lower than the base of the preceding section, a large collection of well preservecl fossils was obtained from a coarse sandy, shell marl. In the list of fossils given below those collected by the writer were from the marl just described, and those collected by Veatch were from parts of the section not designated. The beds exposed at the "Narrows" correspond to the exposure at and near the mouth of Pataula Creek on Chattahoochee River from which Dr. Stanton made exhaustive
.collections. (See pp. 179-180 of this report.)

Pataula Creek, Clay County, Ga., the "Narrows/' two miles above
junction with Chattahoochee River and nine miles north of Fcrt
Gaines. Collectors, Otto Veatch and L. 1r. Stephenson.

GEOLOGY OF THE COASTAL PLAIN OF GEORGIA.

PLATE XVI.

TITE " :>IARR O\Y S OF PATArLA RENK. NINE MILES GAINES. BOWI:'IIG TEN FEET OF ALCAREOUS MARINE SAND WITH J:'IIDU RATED LAYEH. Ob. TUP. RIPI~EY FOR)!ATIO::'\ .
WAT E RFALL AT UPPER END OF THE " ~ARROWS " OF PATA ULA PRODUCED BY I~DURA'l' ED CALCAREOUS LAYER AT TOP

RIPLEY FORMATION

185

Locality Number.

0. v.

5376b

Echinodermata: Cassidulus

porrectus

Clark

(rdentrfied

by

W.

B.

Clark

)

I
1

X

Vermes:

I

Serpula sp. cf. (s. cretacea (Conrad) Mollusca:

I

Nucula percrassa Conrad . . . . . .

Nucula sp. a (cf. N. slackiana Gabb)

Nucula sp. b . . . . . . . .

Perrisonota protexta Conrad

Leda pinnaforma Gabb (var. ?)

Cucullaea sp. . . . . . . . . . .

Breviarca cuneata Gabb . . . .

Nemodon eufalensis Conrad (var. ?) Glycymeris subaustralis (d'Orbigny)

. . . 1

Exogyra costata Say . . . . . . . .

X

Ostrea sp. . ....................... .

Trigonia angulicostata Gabb

. . . .

Anomia argentaria Morton

Anomia sp. nov. . . . . . .

Pholadomya sp. nov.

X

Crassatellites pteropsis Conrad

Crassatellites sp. . . . . . . . . . . ....

Lucina swedesboroensis Weller ?

Lucina sp. nov. . . . . . .

Tenea pinguis Conrad

Cardium eufaulense Conrad

X

Cardium eufaulense Conrad (var. ? )

Cardium spillmani Conrad . . . . .

X

Cyprimeria depressa Conrad . . . . . . ..

Legumen planulatum (Conrad)

Aenona eufalensis Conrad . . .

Linearia carolinensis Conrad ?

Linearia sp. nov. . . . . . . .

Leptosolen biplicata Conrad . . . . . . . . ..

Cymbophora lintea (Conrad) ?

Corbula sp. . . . . . . . . . . . . . . . . . . .

Undetermined pelecypods . . . . . . . . .... .

Dentalium sp.

Eulima sp. . . . . . . . . . . . . . . . . .

Solarium ? . . . . . . . . . . . . . . . . .

Lunatia obliquata Meek & Hayden . . . Lunatia sp. . . . . . . . . . . . . . . Turritella trilira Conrad Turritella sp. nov. (two spiral ridges) .
Pterocerella tippana Conrad . . . . . .

.............jI

X X

: : : : :!

Anchura sp.

0



0



Ancilla sp. . . . . . . .



0



Actaeonina sp. . . . . . Cylichna recta Gabb . .

...... I

Undetermined gastropods . . . . . . . . . .

0



Vertebrata:

Corax falcatus Agassiz . . . . . . . . . . . Undetermined shark's tooth Monotygma sp. . . , . . . . . . . . . . . .

:I

IL. W.S. 6412
I
I j
X X X X X X X X X X X X X X X X
X X X X X X X X X X X X X
X X X X X X X
X X X

186

GEOLOGY OF THE COASTAL PLAIN

At Credilles :Mill, Pataula Creek, about one mile abon~ the "S ar-
rows," Vcatch collected the following fossils from a horizon probably slightly higher than the marl bed described in the preeeding section:

Locality No. 5376a.-Credilles 1llill, Pataula C'1eek, about one mile above the ''Narrous," Clay Gowdy, Ua. Offo l"eafch, collectm.

Echinodermata:

Cassidulus conoideus Clark (Identified by W. B. Clark)

Vermes:

Serpula cretacea (Conrad

. Mollusca:

Cucullaea littlei (Gabb)

Cyprimeria depressa Conrad

Breviarca cuneata (Gabb)

Volutomorpha sp.

Glycymeris subaustralis (d'Or- Undetermined gastropod

bigny)

The beds exposed on Pataula Creek and on the river near the mouth of the creek are in stratigraphic position near the extreme uppermost part of the Ripley formation.
Typical marine beds of the formation are exposed at numerous localities in Ste>vart Conntv.
About one and one-half" miles east of Coffinton, in a deep gully just north of the road leading east to the Eufaula-Lumpkin road, the following fossils were collected from dark gray marine sands, with indurated layers, about 100 feet: belmv the level of the road:

Locality No. 5382.-0ne and one-half miles east of Coffinton,. Ga.

Mollusca:

Collector, L. W. Stephenson.

Ostrea subspatulata Forbes

Anomia argentaria Morton

Exogyra costata Say

Baculites sp.

\bove the fossil layer at the preceding locality the marine ma-

terials appear to grade up into fine, unconsolidated sand, which may

represent the basal part of the overlying Providenee sand member.

The fossil horizon probably corresponds approximately to the horizon

exposed at J\Iercers Mill in Quitman County, Ga. (seep. 182 of this

report), anl at Eufaula, Ala. (see p. 175 of this report.)

The basal -0 feet of the section exposed in the deep gully near

Providence postoffice (now abandoned), described on page 194 of this report, is made up of typical marine beds of the Ripley formation.

Among the casts observed near the top of layer ?\o. 1 in that section

the following forms were recognized: Serpula sp., Leda sp., Cucnl-

lCEa sp. (large), Cardium sp. (with spines), Cardium eufaulense Conrad ( ?) , Oyprimeria depressa Conrad, Leptosolen biplicata Conrad, and T unitella trilira Conrad. Tn the shell layer at the base

E,rogyra costata Say and Cyprimeria. depressa Conrad, were recog-

nized.

RIPLEY FORMATION

187

Four mile~ north of Lumpkin the following interesting section is exposed where the road passes down a steep northward-facing slope known as J olmsons Hill.

~ection, .fohnsons Hill, Lumpkin-Luumlc road, j'our miles north of

Lumpkin.

Upper Cretaceous. Ripley formation (Exogyra costata zone). (Providence sand member).
5. Reddish brown, rather fine, ferruginous, somewhat argillaceous, weathered sand. Grades downward into next layer . . . . . . . . . .
4. Weathered, pinkish, somewhat argillaceous, ferruginous sand . . . . . . . . . . . . . . . .
(Typical marine beds) 3. Fine, greenish, micaceous sand, weathered in the upper part to pinkish anP. yellowish tints . . . 2. Fine, greenish gray, calcareous, more or less argillaceous, marine sand with indurated ledges about 6 inches thick, 2 to 5 feet apart. Fossiliferous. One specimen of Pholadomya sp. nov. 12 ft. below top . . . . . . . . . . . . . . . 1. Dark gray, massive, argillaceous, calcareous sand, with indurated ledges similar to those in layer No. 2. Fossiliferous . . . . . . . . . . . . . .

Feet.
15 8
20
40 22

The fossils listed below were obtained in lavers Nos. 1 and 2 of

the preceding section. The fossiliferous part ;f this section is prob-

ably approximately at the same stratigraphic level as the Cretaceous

section of Enfanla, Ala., although the presence of the large Phola-

dornya may indicate a slightly higher horizon.

J ohnsons Hill, Stewart County, Ga., fovr miles north of Lumpkin on Lurnpkin-l~onmle road. Collecfo1's, Otto Veatch and L. W. Stephenson.

Locality Number

0. v. IL- w. s.
5375 6418-a-j

Mollusca:

I

I

Ostrea tecticosta Gabb . . . . . . . . . . . . .

.I Ostrea plumosa Morton . . . . . . . . . . . . ...... .
Ostrea larva Lamarck var. falcata Morton ... .

I

Gryphaea vesicularis Lamarck (varieties) ... .

I ~
I X

Exogyra costata Say . . . . . . . . . . .

I X I X

Exogyra costata var. cancellata Stephenson

.. I X I X

Trigonia thoracica Morton ? . . . . . Pecten quinquecostatus (Sowerby)

.. I . . . . .I

I X
X

Lima reticulata Forbes . . . . . . . . . . . . . . .... -~

X

Anomia argentaria Morton ................. . X

X

~~;~~am~~- s~~br~ ( M-o~t~~). . . ..... .. . : : : : . . . . : I X

X
X

Pholadomya sp. nov. (same as sp. nov. from Pataulal

Creek) . . . . . . .

.

. . . I

X

Turritella trilira Conrad . . . . . . . . . . . . . . . . . . -I

X

188

GEOLOGY OF THE COASTAL PLAIN

In the extreme northeastern corner of Stewart County the typical marine beds are well exhibited in a se1ies of cuts of the Seaboard Air Line Railway from Renfroes Station northward for a distance of one and one-quarter miles.
At the north end of the first cut near the water tank the the following s~ction was made:

Section in cut of Seaboard Air Line Railway, one-quarter mile north of Renfroes Station.

Upper Cretaceous.
Ripley formation (Exogyra costata zone). (Providence sand member). 5. Gray residual sand . . . . . . . . . . . . . . . 4. Red, ferruginous, slightly indurated, rather coarse
sand . . . . . . . . . . . . . . . . . . . . . . 3. Light gray, coarse, massive sand, partially mottled
with yellow . . . . . . . . . . . . . . . . . . 2. Gray, pebbly, argillaceous sand with numerous
small angular quartz pebbles up to one inch in diameter, poorly exposed . . . . . . . . . . . (Typical marine beds)
1. Dark greenish gray, compact, massive, calcareous clay, resembling an impure phase of the Selma
chalk of Alabama . . . . . . . . . . . . . . .

Feet. 3
4 to 7 5 5
4

From the cut just described northward for one mile there are a number of cuts exhibiting marine sands and clays. The track passes down a steep grade to the north. The thickness of strata exposed could not be determitned with exactness, but the beds are nearly horizontal, and it is probable that the amount does not exceed 60 or 70 feet. These are the type occurrences of the "Renfroes marl" of Veatch. The best section is f,urnishcd by the cut farthest north.

Section in cut of Seaboard Air Line Railway, one-quarter mile north of Renfroes Station.

Upper Cretaceous. Ripley formation (Exogyra costata zone). 3. Weathered, yellow, fine, calcareous, sand with an indurated, calcareous, nodular layer 5 feet above base. Fossiliferous. One specimen of Pholadomya sp. nov. 10 feet above base . . . . 2. Gray, massive, calcareous, sandy clay, with an indurated, nodular, calcareous layer 3 feet above base. Resembles certain impure phases of the Selma chalk in Alabama. Fossiliferous . . . . 1. Massive, argillaceous, micaceous sand, apparently non-fossiliferous . . . . . . . 1

Feet.
20 25
7

The following list is compiled from collections obtained from the exposures in the several cuts from one-quarter to one and one-quarter miles north of Renfroes station. Most of the specimens were found

RIPLEY FORMATION

189

loose on the talus slopes, having weathered from the beds. On account of the mixing of the specimens on the talus slopes, and because all the species identified (with the exception of the new species of Phola:domya whose position in the section is indicated) are wideranging within the zone of Exogyra costata, no attempt is made to designate in which of the above described layers they ~were originally in place. The stratigraphic position of the beds exposed in these cuts probably corresponds approximately to the Cretaceous portion of the section at Eufaula, although the presence of Pholadomya sp. nov. may indicate a slightly higher position in the section for layer No.3.

Cuts of Seaboard Air Line Railway, one-quarter to one and onequarter miles north of Renfroes Station, Stewart County, Ga.

L. IV. Stephenson, collector.

Loc. Nos. 6413-6417.

Mollusca:

Cucullaea sp.

Pecten quinquecostatus (Sowerby)

Ostrea tecticosta Gabb

Pecten sp. nov. ?

Ostrea' larva Lamarck

Dianchora sp.

Ostrea plumosa Morton

Lima reticulata Forbes

Grymphaea vesicularis Lamarck Anomia argentaria Morton

(varieties)

Paranomia scabra (Morton)

Gryphaea sp. (small)

Paranomia sp. nov.

Exogyra costata Say

Pholadomya sp. nov (same as sp.

Exogyra costata var. cancellata nov. from Pataula CreekJ

Stephenson

Vertebrata:

Ischyrhiza mira Leidy (Iden. by J. W. Gidley)

The typical marine beds of the formation have been penetrated in two wells in Stewart County. Information concerning the strata penetrated in these wells has been obtained from the owners, as follows:
G. L. \Valton, of Charles, Ga., owns two wells; one, 65 feet deep, located near the station at the hivel of the track (Seaboard Air Line Railway), and another 85 feet deep, seven-eighths of a mile east of the station, 80 feet above the level of the track. :Mr. \V alton states that "the land is underlaid with hard marl and no one in the neighborhood has ever been able to carry a well through it."

Log of well owned by E. H. Acker, two miles southwest of Charles,

Georgia.
Upper Cretaceous. Ripley formation. (Exogyra costata zone). 3. Sand . . . . . . . . . . . . . . . . . . . . . . . 2. Hard, dark brown, and gray, streaked clay, with one small layer of sand, water-bearing .
1. Black marl at bottom of well .

Feet.
0 to 10
10 to 26 ?

Total . . . . . . . . . . . . . . . .

26

190

GEOLOGY OF THE COASTAL PLAIN

11r. Acker states that the black marl has been encountered in other wells in this neighborhood.
Mr. C. Y. Stephens, of Renfroes, states that blue marl is encountered 10 to 15 feet below the surface in wells one and one-half miles west of Renfroes, and that wells 90 feet deep have failed to penetrate through this kind of material.
In }lariou County weathered phases of the typical marine beds of the formation appear at intervals in the Buena \Tista-Tazewell road, from t\Y() to four miles northeast of Buena Vista.
Prof. S. \Y. }IcCallie' has published the log of a deep well drilled at Buena Vista, \Yhich throws light on the character of the strata underlying the central part of the county. It is as follows:

Log of well at Beuna V isla, Ga.

Feet.

Blue clays . . . . . . . . . . . . . . . . . . . . . . . . . .

0- 35

Sand and clays ......................................... 35-105

Sort limestone . . . . . . . . . . . . . . . . . . . . . . . . . . 105-155

Marl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155-158

Rock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158-159

Marl . . . . . . . . . . . . . . . . . . . . . . . . . . 159-252

Flint . . . . . ................................... .... 252-254

Indurated marl .. '. . . . . . . . . . . . . . . . . . . . . . . . 254-263

Hard rock .......................................... 263-270

Marl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270-297

Limestone (water-bearing) . . . . . . . . . . . . . . . 297-331

Coarse gray sand . . . . . . . . . . . . . . . . . . . . . . . . . 331-343

Marl (water-bearing) . . . . . . ........................ 343-364

Marl . . . . . . . . . . . . . . . . . . . . . . . . . . 364-551

Hard, compact rock . . . . . . .......................... 551-583

The npper 105 feet of strata described in the above log is referable to the Providence saud member of the Ripley formation, and the remainder of the section are typical marine beds of the same formation.
Profe,.;,;or }lcCallie has collected fossils in Marion County from marine materials in the E.Togyra costata zone, as enumerated in the following lists:

Locality 'Xo ..W:)2.-Bivens Plantation on Dry Creel.:, ih1ee miles //'est of hueville. .Marion County, Ga. S. W. llfcCallie, collPcfor.

Mollusca: Ostrea tecticosta Gabb Gryphaea vesicularis Lamarck Exogyra costata Say Exogyra costata var. cancellata Stephenson '

Anomia argentaria Morton

Paranomia scabra (M.orton)

Cardium sp.



'Gcol. Snrv. of Ga., Bull. No. 15, l!l08, p. 146.

RIPLEY FORMATION

191

Locality Ko. 30:)3.-Lanneyhassey Creel.:, four miles sovfh of Buena: Vista, Jfarion County, Ga. S. 1Y. McCallie, collector.

:Mollusca: Cucullaea sp. Inoceramus sp. Exogyra costata Say

Pecten argillensis Conrad Cardium eufaulense Conrad ? Panopea decisa Conrad

Locality Xo. :w:14.-Cul ill public: road nea.r Crntral of Ge01gia
Railway bl'idge across 1Yinchafoonrr crrcl., fire miles north II'PS! of Burna l'ista, J!arion County, Ga. 8. 11". J!cCallir. Collrtfor.

Mollusca:

Veniella sp. (cf. sp. from Hodges old mill, S. C.) Cardium (Trachycardium) alabamense Gabb Aphrodina sp. Turritella trilira Conrad

Fossils hme been collected from typica1 mari nc he\ls of the formation at one place in Schley County. This locality is at the water mill of J. L. B. Usry, seven miles north of Ellaville and one-half mile east of Murray Crossroads. The fossils were obtained just below the ivest end of the milldam from a poor exposure of light green to greenish yellmv, massi,e, marine sand, indurated in layers at the \Yater's edge, anc1 one foot above the water's rc1ge. The remains consist of vcr~- soft she11s and shell prints. The forms listed hrlO\i' \Yere recognized :

Locality No. (J-'!-82.-List of fossils from J. L. B. Usry's milt, seuen miles north of Ellarillc, Ga., and onr-half mile cast of Jiurmy Cross1oads. L. W. Stephenson, collector.

Mollusca: Nemodon sp. Ostrea plumosa Morton Gryphaea vesicularis Lamarck (small) Exogyra costata Say (small, but apparently typical)
Pecten argillensis Conrad ? Pecten simplicius Conrad Lima sp.
Pecten quinquenarius Conrad Anomia argentaria Morton

P!aranomia scabra (Morton) Pholadomy,a sp.
Lucina sp. Tenea ? Oardium spillmani Conrad Cardium sp. Legumen planulatum (Conrad) Turritella trilira Conrad Undetermined pelecypods Corbula crassip!ica Gabb

The farthest locality to the eastward at which the typieal marine Ripley beds have been observed is in a cut of the Atlanta, Birmingham & Atlantic Railroad, one and one-eighth miles north of Ideal, Macon County. The section exposed here is described below: (See also plate XII, B.)

192

GEOLOGY OF THE COASTAL PLAIN

Section in cut of Atlanta, Birmingham & Atlantic Railroad, one and one-eighth miles north of Ideal, Ga.

Upper Cretaceous.

Feet. In.

Ripley formation. (Exogyra costata zone.)

7. Loose, yellow, pebbly sand, probably creep .

4

6. Yellow massive fine, micaceous, argillaceous sand,

a weathered marine sand

7

5. Gray, laminated, micaceous, sandy, marine clay,

with fine sand partings . . . . . . . 4

4. Weathered, fine, yellow, argillaceous, marine sand 8

3. Iron crust .

lh

2. Dark, gray, finely arenaceous and micaceous, corn

pact clay, weathering somewhat shaley. Con-

tains poor prints and casts of fossils . . . . . 20

1. Dark gray to yellow, '!Ilassive, marine sand with

numerous fossil prints at south end of cut .

4

The fossils listed below >vcre obtained from layers K os. 1 and 2

in the above section.



Locality No. 6483.-List from cut of Atlanta, Birmingham & Atlantic Railroad, one and one-eighth miles north of Ideal, Ga. At base of layer No. 2. L. W. Stephenson, collector.

Mollusca:
Cucullaea vulgaris ::vrorton ? Crassatellites sp. Crassatellites pteropsis Conrad Cardium spillmani Conrad Cardium sp. Vertebrata:
Larnna texana Roemer Corax falcatus Agassiz Otodus appendiculatus Agassiz?

Gyprimeria depressa Conrad Cyprimeria densata (Conrad) Aphrodina sp. Cymbophora lintea (Conrad) ? Turritella trilira Conrad
Fragments of bones Tooth of mosasauroid reptile (ldent.
.by C. W. Gilmore)

At Marshallville in the eastern part of Macon County, beds >Yhich probably represent the eastward buried extension of the typical marine beds have been penetrated m a well boring. (See section, p. 197 of this report.)

Region between Chattahoochee and Ocmulgee nvers (Providence sand member).-\Yestward from Chattahoochee River in Alabama, and northeastward from the river in Georgia, the uppermost of the typical marine beds of the Ripley formation merge into shallow water equivalents. These strata constitute the Providence sand of Veatch. In this report they are treated as a member of the Ripley formation.
The points farthest south in Georgia where the Providence sand has been observed are in two cuts of the Central of Georgia Railway, five and three-quarters and six miles, respectively, southeast of Eufaula, Ala., in Quitman County, Ga. The first cut reveals 20 or 25 fret of coarse, irregularly bedded, rrcl<lish and yellowish sands

GEOLOGY OF 7'HFJ OO ASTA L PLAIN OF GFJORGIA. A. CUT OF SOUTHERN RAILWAY 0 1 E-TEIIRD MILE NORTH OF ZENITH STA-
TIO . CRAWFORD COUNTY, SHOWING CO TACT BETWEEN THE RIPLEY FORMATION AND SAND OF PROBABLE EOCENE AGE.
B. CUT OF ATLANTA, BIRMINGHAM & ATLANTIC RAILROAD, ONE AND O:NR!EIGHTH MILE NORTH OF IDEAL. MACON COUNTY. GA., SHOW! G MARINE SANDS AND CLAY OF THE RIPLEY FORMATIO .

RIPLEY FORMATION

193

with iron crusts at intervals. The base of the sands of this character is not clearly revealed, but the relations are such as to show conclusiYely that they occupy a stratigraphic position closely above the uppermost of the marine beds in the section three-quarters of a mile northwest of this point, described on page 183.
The second cut, six miles from Eufaula, reveals the contact between the Providence sand member and the overlying Eocene beds. The relation between these divisions are shown in Fig. 13.

SE.

NW.

~}~

k-------------------------- 400'
Fig. 13.-Section in cut of Central of Georgia Railway, six miles southeast of Eufaula, Ala., in Quitman County, Ga.
Explanation of Figure.
Eocene. 2. Deep red, ferruginous, coarse sand massive in appearance in upper weathered portion; lighter in color, coarser, and showing some crossbedding along base; in lower 2 or 3 feet contains reworked clay balls, iron crusts, and in places angular quartz pebbles up to 2 inches in diameter.
Upper Cretaceous. Ripley formation (Providence sand member) 1. IJoarse, crossbedded, light gray, yellowish and pinkish sand with subordinate lenses of drab, pinkish, coarsely sandy, massive clays.
Layers 8 to 15 inclusive in the section at Stewarts Hill on Chattahoochee River, five and one-hal milea a:bove Eufaula in Quitman County, Ga., described on page 174, probably represent the transition from the typical marine beds of the formation to the overlying Providence sand member.
An excellent exposure of the Providence sand member is furnished by a deep gully to the west of the Eufaula-Lumpkin road, 10% miles northeast of Georgetown, Ga. According to aneroid estimates the elevation of the road at this point is about 350 feet above the floor of the wagon bridge at Eufaula. The gully which is down the slope to the west of the road, exposes about 100 feet of materials consisting principally of coarse, crossbedded, varicolored sands with occasional clay lenses. The sands in places contain numerous small clay balls and one layer of large clay boulders \Vas observed. Occa-

Iii:\:

194

GEOLOGY OF THE COASTAL PLAIN

sional'iron crust layers occur. The base of the section is about 130 feet below the level of the road. (See plate XVIII, A.)
The most complete section of the Providence sand member is furnished by a series of deep gullies near Providence, an abandoned postoffice eight miles a little north of west of Lumpkin. This is the type locality for this division. One of the gullies just south of the J.,umpkin-Florence road shows the relation of the division to the overlying Eocene beds. The section follows :

Section in gully south of Lumpkin-Florence road near Providence P. 0. (now discontinued), eight miles a little north of west of Lumpkin, in Stewart County, Ga.
Feet. ,
5. Dark red, sandy loam with iron crusts at base. . . . . . . . 15 (Unconformity)

Upper Cretaceous. Ripley formation. (Providence sand member.)

4. Irregularly bedded, white, yellow, red and purple,

fine to medium grained sand, somewhat ar-

gillaceous in places . . . . . . . . . . . . . .

120

3. Yellow, argillaceous sand, becoming more argilla-

ceous towards base. Conformably overlies the

next layer below . . . . . . . . . . . . . . .

10

(Typical marine beds).

2. Dark gray, thinly laminated, finely arenaceous and

micaceous clay. Contains some bits ot lignite

and small bits of amber . . . . . . . . . . .

15

1. Dark greenish gray, mic3iceous, slightly argillace-

ous and glauconitic sand, with numerous soft

fossil casts in the upper part and with shells in

the lower 2 or 3 feet . . . . . . . . . . . . .

25

On the hill slope above the top of the preceding section there are poor exposures of white Eocene limestone containing poorly preserved fossils. A similar limestone outcrops in the road, two or three miles to the east towards Lumpkin.
In a cut of the Seaboard Air Line Railway, just east of the station at Lumpkin, Stewart County, the supposed top of the Providence sand, consisting of several feet of light-colored, very sandy clay, is seen, overlain by four to six feet of iron-stai,ned ferruginous clay bearing a few very poorly preserved shell impressions, the latter regarded as the base of the Eocene.
Northward from Lumpkin on the Lumpkin-Louvale road, there are numerous exposures in which the beds of this formation appear. The following section was made in an abandoned railroad cut, one and one-half miles north of Lumpkin:

RIPLEY FORMATION

195

Section in abandoned railroad cut just west of Lumpkin-Louvale road, one and one-half miles north of Lumpkin, Ga.

Eocene ? 2. Reddish brown, ferruginous, coarse sand . . . . (Unconformity, undulating, slightly irregular,
sharp oontact, marked in places by a thin iron crust.) Ripley formation.
(Providence sand member.) 1. Variegated, white, yellow, pink, red and purple, very coarse sand, crossbedded and loose, where locally indurated to ferruginous sandstone . .

Feet. 20
30

The supposed Cretaceous-Eocene contact in the section just described is about 70 or 75 feet below the general upland level.
To the north o the preceding section the road is over deep red, compact, ferruginous sand, probably referable to the Eocene, to a point two and one-hal miles north of Lumpkin, where it passes into coarse, light-colored, loose sands residual rom the Providence sand.
At three and three and one-hal miles, respectively, north o Lumpkin, the coarse, crossbedded sands o the Providence sand member are well exposed in gullies about 50 or 60 feet in depth.
No detailed observations were made along the Seaboard Air Line Railway south o Renroes. However, between Renroes and Brooklyn the coarse sands o the Providence member were seen from the train in shallow cuts and in gullies on the hill-slopes. Between Brooklyn and Richland the sub-soil or the greater part o the distance is red, and has the characteristic appearance o the basal Eocene beds o the region.
The logs o a number o wells in Stewart County which penetrate Cretaceous strata are given below. In each case the authority for the lithology is the owner unless otherwise stated.

Log of well owned by W. S. Boyett, four miles south of Lumpkin, Ga.

Eocene ? 5. Red clay . . . . . . . . . . . . . . .
Upper Cretaceous.
Ripley formation. (Providence sand member.) 4. "Chalk" (clay) white and pink . . . . 3. Coarse sand with small rock (pebbles) 2. "Chalk" (clay) . . . . . . . . . . . . 1. Thick layer of white sand . . . . . . ("and so on until water was struck.")

0- 30
? ? ? ?

Total . . . . . . . . . . . . . . . . . . . . . . . 70
In another well132 feet deep, located 25 yards rom the preceding, water was obtained in coarse sand 128 to 132 feet below the surface. It is probable that all the strata penetrated in this well below the red Eocene clay should be referred to the Providence sand member.

196

GEOLOGY OF THE COASTAL PLAIN

Log of well owned by Mrs. Marion Glenn, one mile southeast of Brooklyn, Ga. Authority for lithology, J. M. Glenn, of Brooklyn:.

Eocene.
4. Red clay with gravel rock (pebbles) Upper Cretaceous
Ripley formation (Providence sand member). 3. "Chalk" (clay) . . . . . . . . . . . . 2. White and yellow sand and occasionally a bed of rock four to five feet thick, water-bearing at base 1. Stopped in "chalk" (clay) .. _ . . . . .

0 - 30
30 - 40 40 - 110
?

Total

110

A 140-foot well located 50 feet from the preceding is said to have penetrated similar materials.

Log of well owned by E. M. Averett, one-quarter mile east of Renfroes, Ga. Authority for lithology, C. V. Stephens, of Renfroes, Ga.

Upper Cretaceous.

Feet.

Ripley formation. (Providence sand member ?)

4. Sand, gray or white . . . . . . . . . . . . . . . . . . . . . 0- 8

3. Light yellow, firm clay . . . . . . . . . . . . . . . . . . . . 8-26

2. Soft, yellow sand . . . . . . . . . . . . . . . . . . . . . . . 26-56

1. Sand and clay, water-bearing . . . . . . . . . . . . . . . . 56-60

Coarse, light-colored sands and clays o the Cusseta sand member

o the formation appear in cuts and in other exposures in the imme-

diate vicinity of Buena Vista, Marion County.

The supposed contact o the Providence sand member with the

overlying Eocene is seen in a cut o the Central o Georgia Railway,

one mile southeast of Buena Vista. (See plate XVIII, B, opposite

p. 208.) The section here is as follows:



Section in cut of Central of Georgia Railway one mile southeast of Buena "Vista, Ga.

Eocene ?

Feet. In.

5. Dark red, massive sand with a line of small peb-

bles and iron crusts, 1% feet above base . . . 9 6

4. Irregular layer of iron crusts and botryoidal iron

concretions with some admixture of argillaceous

sand, average . . . . . . . . . . . . . . . . . 1

3. Light drab clay mottled with yellow, with irregular

patches of yellow limonitic clay along base .

3

2. 'Slightly undulating iron crust . . . . . . . . . .

14

(Unconformity ? )

Upper Cretaceous ?

Ripley formation. (Providence sand member.)

1. Light drab, massive clay, mottled with yellow

apd purple, containing irregular iron concretions 5

/

The Providence sand outcrops in Schley County in a belt two or

three miles wide extendin~ east and west just north o the center of

the county. Little is known of the details of its occurrences.

RIPLEY FORMATION

197

In Macon County the underlying typical marine beds of the formation are believed to merge finally into materials of the Providence sand type, at least so far as surface outcrops are concerned. Beyond this county to the eastward the Providence sand makes up the entire thickness of the Exogyra costata zone, the beds resting directly and conformably upon the Cusseta sand member of the formation.
The supposed contact of the formation with the superjacent Eocene beds was observed at an exposure at Barrows Mill, about four and one-hal miles east of Marshallville. (See Fort Valley soil map, one and one-fourth miles southeast of Willow Lake, in square bearing the number 161.)

Section at Barrows Mill, Houston County.

Eocene

3. Reddish, sandy loam (weathered) . . . . . . .

3

2. Brownish, argillaceous sand and sandy clay, dark

to black where unweathered, containing Eocene

fossils . . . . . . . . . . . . . . . . . . . .

4

(Unconformity ? )

Upper Cretaceous.

Ripley formation (Providence sand member) ?

1. Light gray, very coarse, very arkosic sand,

streaked in places with yellow . . . . .

8

A well mYned by the town of Marshallville in Macon County, penetrated strata referable to the Ripley formation, from a depth of 25 feet to the bottom. The log given below was furnished by the contractor, J\fr. M. N. Brewer. It is copied from Bulletin No. 15 of the Geological Survey of Georgia, 1908, p. 145.

Log of well at Marshallville, Ga.

Feet.

10. Yellow clay . . . . . . . . . . . . . . . . . . . . . . . . . . 1- 25

9. Sand with some pipe clay . . . . . . . . . . . . . 25- 90

8. Fine gray sand . . . . . . . . . . . . . . . . . . . . . . 90-185

7. Brownish sandy clay . . . . . . . . . . . . . . . . . . . . . . 185-230

6. Fine gray sand . . . . . . . . . . . . . . . . . . . . 230-270

5. Sand and blue marl . . . . . . . . . . . . . . . . . . . 270-320

4. Clay . . . . . . . . . . .

. 320-370

3. Thin layers of limestone . . .

. ..

. 370-380

2. Very hard rock . . . . . , . . . . . . . . . . . 380-390

1. Sand (water-bearing) . . . . . . . . . . . . . . . 390-397

The upper 25 feet of the materials described in the preceding well should probably be referred to the Eocene. The beds from 25 to 370 feet probably belong to the Providence sand member of the Ripley formation; those from 370 to 397 are believed to form the eastward buried extension of the typical marine beds of the Ripley formation.

198

GEOLOGY OF THE COASTAL PLAIN

Veatch, in his clay report, pp. 209-211, and 215-217, has de-
scribed Cretaceous clay deposits in Houston County, a part of which are believed to be referable to the Providence sand member. The following are quot~tions from his report:

"In Houston county notable deposits of white clay were observed in the

vicinity of Perry, Fort Valley, and Byron. With the exception of clay min-

ing at Perry, there are no clay industries in the county, and the clay deposits are undeveloped.

"Perry-A deposit of kaolin occurs on the Yancey property on Bay Creek, two m.iles northwest of Perry. This clay was described by the writer

in Bulletin 315 of the United States Geological Survey, but since the above

description was written a small mine has been opened up and the property
to some extent developed * * * . The clay bed at the point mined

has shown a maximum thickness of 18 feet. The clay is soft, massive bedded

and jointed, though the jointing is not as extensive as in the Dry Branch

region, and slickensided surfaces along the joint planes were not observed. The bed upon the whole is very free from sandy impurity, but it may grade
into or be replaced by sand, and may be split by sand layers. * * *
"The overburden consists of very fine variegated, quartz and micaceous

sands which 7ill show a maximum thickness of about 80 feet. "A pocket of white clay was noted on the Macon road, 5 miles northeast

of Perry. The clay is exposed in a gully along the public road near the

crossing of Mossy Creek. The deposit, owing to its inaccessibility, is of no

value at present, but is instructive in showing the geological occurrence of the white clays. of the Upper Cretaceous ( ?) . The deposit is lens-shaped or
cigar shaped, having a maximum thickness in the center, and tapering at

each end; the full extent of the bed can be observed. The bed is about 100

feet in length, and has a maximum thickness of 8 feet and is overlain and underlain by red sand. Doubtless numerous other outcrops of white clay
may be found eastward from Perry. "Bonaire.-Bonaire is located on the Georgia Southern and Florida Rail-
road in the eastern part of Houston county, and is about 23 miles south of

Macon. A deposit of white clay lying about four miles southeast of this

place, on the property of Chas. Thompson, has attracted some attention on account of the conspicuousness of the outcrop. The clay is exposed at the

base of a steep bluff bordering the Ocmulgee River swamp, and the bed is

laid bare by the water flowing from a rather bold spring above it. The follow-

ing is a vertical section of the bluff:

6. Loose, brown sand .

6

5. Thin, drab clay layer

3

4. Red sand . . . . . .

4

3. White stained clay . .

4

2. White sand . . . . . .

15

1. White stained clay . . . . . . . . .

10+

"The clay bed, No. 1, is semi-hard, bluish white, with purplish and yellow

stains of iron oxide, which seem to- permeate the mass of the clay a:nd are not

merely surface stains. Doubtless a greater thickness than is shown above,

will be found; the lateral extent of the bed has not been determined, but no

natural exposure of it were seen either to the north or to the south of the
outcrop at the spring. It is believed the strata here belong to the Upper Cretaceous sands, a characteristic of which is lens-shaped beds of clay, rather

restricted in area."





The logs of several wells in this county which are believed to penetrate strata of the Providence member are given below. Thf! owners are authority for the lithology, except as otherwise indicated.

RIPLEY FORMATION

199

Log of well owned by T. W. Leverett at Wellston, Ga.

Pleistocene ? 2. Stiff, hard, red clay, about . . . . . . . . . . . .
Upper Cretaceous ? Ripley formation (Providence sand member) 1. Coarse sand with numerous flint rocks (pebbles) as large as end of the thumb, water-bearing in lower eight feet . . . . . . . . . . . . . . .

Feet 0-40
40-68

Log of well owned by J. A. Smith, three and one-half miles west of

Wellston, Ga.

Eocene ? 2. Solid red clay . . . . . . . . . . . . .. . . . . .
Upper Cretaceous Ripley formation (Providence sand member) 1. Yellow and white sand, in part fine alternating
with "chalk" (clay), water-bearing in sand in lower 3 feet . . . . . . . . . . . . . . . . .

Feet. 0-20
20-93

Log of well owned by W. A. Stubbs and one-ha;lf miles east of Wells

ton, Ga.

Eocene ? 2. Hard red clay . . . . . . . . . . . . . . . . . .
Upper Cretaceous

Feet. 0-25

1. Alternating beds of "chalk" (clay) and sand of various colors, white, bluish, yellow, etc., water-

bearing below 207 feet . . . . . . . . . . . .

25-216

Doubtless all of the sand and clay beds included in division No. 1 of the above log are referable to the Upper Cretaceous. The upper part of the division is believed referable to the Providence sand member of the Ripley formation, but it is probable that at some depth the well entered the upper strata of the subjacent Cusseta sa:Q.d member of the formation, the latter forming the basal portion of the section and furnishing the water-bearing material.

Log of well owned by T. N. White, three miles south of Dunbar, Ga,

Eocene ? 2. Red clay . . . . . . . . . . . . . . . . . . . . .
Upper Cretaceous 1. White sand, except two layers of "chalk" (clay) each one foot thick, water-bearing in lower 3
feet . . . . .......

Feet. 0-20
20-10(>

Log' of well at Perry, Ga.
6. Red massive clay . . . . .. . . . . . . . 5. White clay . . . . . . . . . . . . . . . . . . . . 4. Yellowish sand, with 4 inches of impervious iron at
its base . ,. . . . . . . . . . . . . . . . . . 3. Sand with thin partings of clay . . . . . . . . 2. Dark carbonaceous materials-possibly hgnite . 1. Coarse gravel at . . . . . . . . . . .

Feet. 0-10 10-10%
103-50 50-132
132-136 136

1Geol. Survey of Georgia Bull. No. 15, 1908, p. 121.

200

GEOLOGY OF THE COASTAL PLAIN

An undetermined upper portion of the section just described is referable to the Eocene, but the greater part of the section belong~
to the Prov\dence sand member of the Ripley f?rmation.

DETAILED SECTIONS. (WELLS SOUTH OF THE BELT OF OUTCROP.)
At a number of places in Georgia well borings have been made that have passed through overlying Tertiary beds, entering and penetrating to various depths the beds of the Ripley formation beneath. Few reliable records have been kept, however, and the available information if meager. A well at Albany, Dougherty County furnishes the most instructive section of any yet recorded from the region. The log of this well was furnished by :Mr. C. W. Tift, of Albany. The fossils, also furnished by ::\Ir. Tift, were determined by Dr. T. Wayland Yanghan. This log was published in Bulletin No. 15 of the Geological SurYey of Georgia, 1908, pp. 98, 99. It is here repeated, and in addition an attempt is made to correlate the Cretaceous portion of the section with the Cretaceous formations eutcropping at the surface to the northward in the State. The writer has examined a part of the Cretaceous fossils obtained from the well and has made one or two slight changes in the determinations.

Lqg of Oity Artesian Well No. 2, Albany, Ga.

Tertiary: 35. Red clay . . . . . . . . . . . . . . . . . . 34. Light colored clay . . . . . . . . . . . . . . . 33. Coarse sand (Vicksburg) . . . . . . . . . . . . 32. Light colored clay and coarse quartz sand . . . . . 31. Limestone, Orbitoides sp. at 150 feet, and from 190 to 200 feet . . . . . . . . . . . . . 30. Gray limestone, Orbitoides sp., Echinoid, Bryozoa, Terebratulina lachryma (Morton), some shale from 230 to 240 feet . . . . . . . . . . 29. Gray sand with comminuted shells ( Ostrea) . . 28. Some shale, coarse sand, shell, and sharks' teeth, at . . . . . . . . . . . .. 27. Hard layer, Ostrea divaricata Lea 26. Ostrea divaricata Lea at . . . . . 25. Ostrea alabamiensis Lea at . . . 24. Shale or marl, water vein at . . . 23. Ostrea divaricata Lea and Ostrea alabamiensis
Lea at ..... 22. Bed of lignite at . . . . . . . . . . . . . . . . 21. Bed of lignite at . . . . . . . . . . . . . . . . 20. Sand . . . . . . . . . . . . . . . . . . . . . . . 19. Stiff blue clay Echinoid spines, Lamna sp. (teeth)
18. Stiff blue clay . . . 17. Hard gray sandstone . . . . . . . . . . . . . .
.Upper Cretaceous Ripley formation. 16. Ostrea sp. and Exogyra costata Say ? 15. Pyrite and small oysters at . . . . . .

Feet. 0- 20 20- 23 23 25 25 35
35-200
200-280 280-285
311 318-320
330 340 350
363 367 400 400-475 470-475 475-480 485-488
500-510 520

RIPLEY FORMATION

201

14. Greensands and greenish micaceous shales

530-540

13. Gray sand with black particles at .

600

12. Water-bearing horizon, limestone, with pieces of

nard gray sandstone between 785 and 790 feet . 690-790

11. Hard rock

790-800

10. Clay shales, white limestone between 835 and 840 800-850

9. Limestone, shales, etc. At 880 feet limestone or

calcareous sand, also light gray micaceous sand 850-890

8. Grayish sand, calcareous, fragments, hard black

pieces of pebbles, Ostrea sp.; Anomia argentaria

Morton.

[Gryphaea vesicularis Lamarck

(young)] at 890 feet; water-bearing micaceous

stone between 920 and 930 feet .

890-940

7. Blue, micaceous clay at 950 feet, thick shelled

oyster, Gryphaea sp., the same also at 1,080

feet; at 1,100 feet gray sand with Ostrea sub-

spatulata Forbes, Exogyra costata Say . . . . 940-1100

6. Stiff blue clay, micaceous sandstone, Ostrea cre-

tacea Morton ( !)

1100-1200

5. Very stiff blue clay, at 1255 feet, streaks of sand

and shells, a small flow of water; from 1240

to 1260 soft shiny blue clay

1200-1260

4. Marl, gray sand, sandstone lumps .

1260-1270

3. Gray and black sand, sandstone lumps

1270-1310

2. Black, irregular, water-worn pebbles with hard

crystalline fracture; coarse and fine quartz

sand, shells, decayed wood, third water-bearing

stratum; 50 gallons per minute

1310-1315

1. Well ends in quartz sand at . .

1320

A well at Blakely, in Early County, entered the upper beds of the formation at some depth between 160 and 500 feet, but probably nearer the latter depth. The log was furnished by l\r. S. S. Chandler and the fossils were determined by Dr. T. wayland Vaughan. This log was published in Bulletin No. 15 of the Geological Survey of Georgia, 1908, pp. 105, 106. It is here repeated.

Log of town well, Blakely, Early County, Ga.

14. Red, sandy clay . . . . . . . . . . .

13. Coarse, grayish sand . . . . . . . .

12. Coarse, light-yellowish sand . . . . .

11. Yellowish cherty limestone (Vicksburg)

10. Yellowish, or grayish, sandstone . . . .

9. Light-colored, almost white, calcareous sand-

stone, probably base of Vicksburg . . .

8. Gray sands, darker at bottom . . . . . .

7. Greenish sands, with Ostrea divaricata Lea

6. Fine gray sand, hard ledge at bottom

5. Fine sand, with some clay . . . .

4. Bluish clay . . . . . . . . . . . . . . . .

3. Quartz sand, with glauconite . . . . . . .

2. Hard sandstone with glauconite. Two oysters,

apparently Gryphaea sp. and Exogyra costata

Say

. . . . . . .

.

.

1. Grayish or bluish sands . . . . . . . . . . . .

Feet. 1- 10 10- 20 20- 30 30- 40 40- 50
50- 70 70-140 140-160 160-285 285-290 290-490 490-500
500-510 510-580

/
'-.

202

GEOLOGY OF THE COASTAL PLAIN

Mr. George R. Irwin, o Fort Gaines, Ga., has furnished the following log o a well drilled by S. S. Chandler, in August, 1909, in Henry County, Alabama, two and one-hal miles northwest o Fort Gaines, Ga. The writer is authority or the attempted correlation:

Log of well owned by George R. Irwin, located two and one-half miles northwest of Fort Gaines, Ga., in Henry County, Ala., on Chattahoochee River bottom, 700 yards west of the river at an elevation of 15 feet above high water mark.

Pleistocene (terrace deposit). 17. Clay and sand .
Eocene.
16. Soft lime rock . 15. Hard lime rock 14. Marl . . . . . . . . 13. Hard lime rock .. 12. Marl . . . . . . . 11. Coarse sand . . Upper Cretaceous. Ripley formation. 10. Hard sand rock (or indurated sand) . . . . . .
9. Coarse sand . . . . . . . . . . . . . . . . . . . 8. Hard sand rock (first flow of 10 to 11 gallons per
minute at this depth measured from top of pump 7 feet above the surface)
7. Coarse sand . . . 6. Hard sand rock . 5. Coarse sand . . .
4. Sand rock . . . . 3. Coarse sand . . . 2. Marl . . . . . . . . . . . . . . . . . . . . . . 1. Hard sand rock with some soft spots. At 230-235
feet the second flow of 25 to 30 gallons per minute was found, flowed this amount from top of 6-inch pipe. Well stopped in the rock . . . .

Feet. 1- 3.0
30- 75 75-125 125-135 135-140 140-170 170-180
180-186 186-190.
190-196 196-202 202-207 207-210 210-212 212-215 215-217
217-240

A number o flowing artesian wells have been drilled at Montezuma. The log o the deepest o these has been published in Bulletin No. 15 o the Geological Survey o Georgia, 1908, p. 142. The log was furnished by Mr. E. J. Wilson, the contractor. It is as follows:

18. Sand to . . . . . 17. White clay to . . 16. Limestone to . . . 15. Sand and clay to 14. Bluish tough clay to
13. Sand with mica to . 12. Blue clay to . . . . . 11. Sand and blue clay to . 10. Fine, micaceous sand to
9. Sand and clay to . . . . . . . . 8. Sand with thin layers of flint to . 7. Clay and fossil wood to . . . . . 6. Limestone containing shells to . .

Feet.
6 18 20 50 60 75 95 155 160 190 310 350 352

RIPLEY FORMATION

203:

5. Micaceous sand to . , . . . . . . . . . .

356

4. Clay interstratified with sand to . . . .

416

3. Fossiliferous limestone with layers of sand to

480

2. Clay to ...

496

1. Sand to . . . . . .

500

No fossils were observed from the above described well and an attempt to distinguish the formations penetrated can be nothing more than a rough guess based upon the descriptions of the materials as furnished by the driller. Layer No. 18 is probably Pleistocene terrace sand; layers 10 to 17 inclusive probably belong to the Eocene; layers 1 to 9 probably include representatives of the Providence sand and the typical marine beds o the Ripley formation. If these correlations are correct the two water-bearing strata referred to by Pro. Jl.fcCallie at 60 and 150 feet, respectively, are Eocene horizons, and those at 350 and 500 feet, respectively, are Ripley Cretaceous horizons.
An oil-prospecting well, located three and one-hal miles southwest o Louisville, in Jefferson County, penetrated Cretaceous strata i~ part. The log is given on page 107 o this report. Fossils characteristic o the Claiborne group of the Eocene were obtained at a depth o 250 feet. A fragment o a turtle plate, supposed to be referable to the Upper Cretaceous, was obtained at a depth of 380 feet. On the basis o these fossils the contact between the Cretaceous and Eocene is believed to be somewhere between the depths indicated, and it is here tentatively placed at 350 feet. Crystalline basement rocks were encountered at 1,140 feet. The probable total thickness of Cretaceous strata penetrated, therefore, is 790 feet.
The data obtained from the Louisville well w'as insufficient to permit distinguishing between Upper and Lower Cretaceous strata, but it is believed that beds of both ages are represented. Doubtless the lower 500 or 600 feet of the Cretaceous portion of the section should be referred to the Lower Cretaceous and the remainder to the Upper Cretaceous, perhaps to the Ripley formation.
Wells at Arlington and Leary in Calhoun County, at Dawson in Terrell County, at Cuthbert in Randolph County, at Fort Gaines in Clay County, at Richland in Stewart County, at Americus in Sumter

204

GEOLOGY OF THE COASTAL PLAIN

County at Oglethorpe in :Macon County, at Perry m Houston County, at Byromville in Dooly County, at Cordele in Crisp County, and at Dublin in I,aurens County, and perhaps at other places, are of sufficient depth to pass through the Eocene deposits and enter the underlying Cretaceous beds. How!3ver, either n'o logs have been kept, or, in cases where logs have been recorded, the information given is too indefinite to permit discrjminating between Eocene and Cretaceous beds. Such detailed information as is knovm concerning these wells has been published by Prof. S. W. :McCallie in Bull. No. 15 of the Geological Survey of Georgia.

CORRELATION
The typical marine beds of the Ripley formation in Georgia are very prolific in fossil invertebrates. On the basis of the ranges of t\YO species of Exogyra the formation has been divided into two . parts. The first part embraces the lower one-third or one-half of the formation and forms the upper part of the zone of Exogyra ponderosa, of which the lower portion is the Tombigbee sand member of the Enta\Y formation. The second part, embracing the remainder of the formation, is characterized by the presence of Exogyra costata and is designated the Exogyra costata zone. These two parts will be considered separately.
Part of Ripley formation included within the zone of Exogyra ponderosa. Omitting numerous forms identified generically out not specifically, and an occasional form whose specific identification . is questioned, 34 species of invertebrates have been recognized in these beds, as follows:

1. Hamulus onyx Morton (Rc. Tp.) 2. Nucula percrassa Conrad (Rc. Tp. Eb.) 3. Cucullaea carolinensis ( Gabb) ( Tp.) 4. Trigonoarca sp. nov. (Roods Bend) 5. Nemodon brevifrons Conrad 6. Barbatia lintea Conrad (Tp.) 7. Ostrea plumosa Morton (Rc. Tp.) 8. Ostrea tecticosta Gabb (Rc.) 9. Ostrea sp. nov. (large, Roods Bend, etc.) 10. Gryphaea vesicularis Lamarck (Rc.)

RIPLEY FORMATION

2Q5

l 1. Exogyra ponderosa var. erraticostata Stephenson ( Tp.) 12. Trigonia sp. nov. (same as sp. nov. from Snow Hill, N. C.) 13. Pecten burlingtonensis Gabb (Tp.) 14. Pecten quinquenarius Conrad (Rc.) 15. Pecten sp. nov. (same as sp. nov. from Snow Hill, N. C.) (Tp. Eb.} 16. Anomia argentaria Morton (Rc. Tp.) 17. Anomia lintea Conrad 18. Anomia sp. nov. (same as sp. nov. from Snow Hill, N. C.)
(Tp. Eb.) 19. Veniella conradi (Morton) (Rc. Tp.) 20. Crassatellites carolinensis Conrad ? (Tp.)
:n. Crassatllites sp. nov. (Roods Bend, etc.)
22. Lucina glebula Conrad (Tp.) 23. Cardium eufaulense Conrad (Rc. Tp.} 24. Isocardia cliffwoodensis Weller ? 25. Cyprimeria depressa Conrad (Rc. Tp. Eb.) 26. Cyprimeria densata (Conrad) (Rc.) 27. Aphrodina regia Conrad 28. Cyclothyris alta Conrad (Tp.) 29. Legumen planulatum (Conrad) (Rc. Tp.) 36. Baroda carolinensis Conrad 31. Leptosolen biplicata Conrad (Rc. Tp. Eb.) 32. Cymbophora lintea (Conrad) CRc. Tp. Eb.) 33. Corbula carolinensis Conrad (Tp. Eb.) 34. Gyrodes crenata Conrad
In the Chattahoochee region, 14 of the 34 specws in the list~
marked (Rc), range up into the overlying Exogyra costata zone; 20, marked (Tp), occur in the underlying Tombigbee member of the
Eutaw formation; 7, marked (Eb), occur in the basal beds of the Eutaw formation, and 10 are restricted to the beds in question. .
The 14 species in the list which range up into the zone of Exogyra
costata are eliminated from further consideration on account of their
wide vertical range. The table given below shows the ranges of the remaining 20 both within and without the Chattahoochee region:

Table showing ranges of species which in the Chattahoochee reg1:on occur in that part of the Ripley formation included within the Exogyra ponderosa zone exclusive of those which range upward into theExogyra costata zone.

206

GEOLOGY OF THE COASTAL PLAIN

. 1. Cucullaea carolinensis (Gabb)

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2. Trigonoarca sp. nov. (Roods Bend, etc.)

X

3. Nemodon brevifrons Conrad 4. Barbatia lintea Conrad 5. Ostrea sp. nov. (large, Roods Bend,
etc.)

X

X

X

X X

x?

X

X xl

6. Exogyra ponderosa var. erratioostata Stephenson
7. Trigonia sp. nov. (Same as sp. nov. from Snow Hill, N. C.)

X XX

X X
X

8. Pecten burlingtonensis Gabb

X

X

x2

9. Pecten sp. nov. (same as sp. nov. from

Snow Hill, N. C.)

XX X

10. Anomia lintea Conrad 11. Anomia sp. nov. (same as sp. nov. from

'

Snow Hill N. C.) 12. Crassatellites earolinensis Conrad. 13. Crassatellites sp. nov. (Roods Bend,

XX XX
x'? X x'?

etc.)

14. Lucina glebula Conrad 15. Isocardia cliffwoodensis Weller. 16. Aphrodina regia Conrad 17. Cyclothyris alta Conrad 18. Baroda carolinensis Conrad 19. Corbula carolinensis Conrad 20. Gyrodes crenata Conrad

X
X x'? x'? X
X
X XX X
XX XX

X

X

X X
X
X X
X X X X X X X X

x X x4 X x"
xs

Note.-See footnotes on page 207.

RIPLEY FORMATION

20~

0 the 20 species restricted below the zone o Exogyra ponderosa in the Chattahoochee region, 10 (one questionably, see oot-note 7 in the table) range down into the underlying Tombigbee sand member o:f the Eutaw ormation. Eight o the species (two questionably, see oot-note 7 in the table) occur in the M ortoniceras sub-zone o the Tombigbee sand in the region to the west o the Chattahoochee region in Alabama and Mississippi. Thirteen (our questionably, see footnote 7 in the table) occur in that part o the zone o Exogyra ponderosa above the M ortoniceras sub-zone in the same region; and two occur in the Exogyra costata zone in northern Mississippi.
In the Carolina region all but one o the 20 species occur in the Black Creek ormation, and one (qr questionably two) ranges up into the overlying Peedee sand.
In New Jersey three o the 20 species occur in the Magothy ormation and five (two questionably, see oot-notes 3 and 5 in the. t;;tble) occur in the Matawan groups. The Merchantville clay marl which orms the basal portion o the Matawan group is believed to correspond approximately to the Tombigbee sand member o the Eutaw ormation (see pp. 145-149 o this report), which underlies that portion o the Chattahoochee section now being considered. By referring to the oot-notes in the table it will be seen that all o the five species occurring in the Matawan groups are present in beds above the Merchantville clay-marl, but that three o .the five also range down into the Merchantville beds.
0 the 20 restricted species given in the table only three are known to range above the zone o Exogyra ponderosa into the zone o Exogyra costata: anywhere in the Atlantic coast and eastern Gul regions.
The conclusions reached regarding the ag(l and stratigraphic relations o the beds under consideration. may be summed up as follows:
In the Chattahoochee region these beds fill in the gap between the underlying M ortoniceras sub-zone o the Tombigbee sand and the base o the overlying Exogyra costata zone. These two delimiting horizons are traceable throughout the greater extent o the eastern Gul Upper Cretaceous, and by this means the equivalents o the

10ccurs in Wenonah sand of Matawan group. 20ccurs in Merchantville clay-marl, Woodbury clay, and Wenonah sand of Matawan group. 'Probably same as Luoina oretaoea Whitfield from the woodbury clay of the Matawan group. Occurs in the Woodbury clay and Wenonah sand of the Matawan group. 'Probably same as Oorbula bisuloata Conrad which occurs in the Magothy formation and in the Merchantv!lle cla;s:-marl and the Woodbury clay of the Matawan group. occurs In the Merchantville clay marl, Woodbury clay, and Wenonah sand of the Matawan group. 7The questionably Identified species Crassatellites carolinensis Conrad and Lucina glebula Conrad, although not confidently referred to these species belong to types of the genus not known to occur above the zone of Exogyra ponderosa.

208

GEOLOGY OF THE COASTAL PLAIN

beds are fixed for practically the whole of the region. The contained fauna as developed in the Chattahoochee region is traceable westward between these limits into Alabama as far as the central part of Bullock County, being well developed in the vicinity of Union Springs. In Bullock County the beds merge horizontally into the strata forming the lower half of the Selma chalk. The conditions under which the chalk beds were laid down appear to have been unfavorable for the existence or for the preservation of many of the species characterizing the fauna in the Chattahoochee region, for in the chalk the fauna is poorly represented; however, many of the forms reappear again in non-chalky representatives of the same beds in northern Mississippi.
The evidence for correlating the beds in question with the invertebrate-beari:r~g beds of the Black Creek formation of the Carolinas is very strong; for of the 20 species restricted below the zone of Exogyra costata in the Chattahoochee region 19 occur in the Black Creek formation, and only one (or questionably two) of the 19 is known in the overlying Peedee beds.
Six of the 20 species (two questionably) occur in the :Matawan group of New Jersey and none of the six are known in the overlying Monmouth formation. The evidence is satisfactory therefore for regarding the Chattahoochee beds under consideration as corresponding to the l\Iatawan group exclusive, however, of the :Merchantville clay-marl which forms the base of the Matawan. For reasons given in a preceding chapter (p. 149) the Merchantville beds are considered the equivalents of the underlying Tombigbee sand member
of the Eutaw formation. The remains of a.few vertebrate animals, consisting of teeth and
fragments of bones, have been found in the formation. The forms thus far identified are given in the list below:
Pisces: Corax falcatus Agassiz Lamna texana Roemer Otodus sp. Ischyrhiza mira Leidy (Identified by J. W. Gidley)
Reptilia: (Identified by C. W. Gilmore.) Fragments of the turtle Taphrosphys Fragment of large dinosaur limb bone Vertebra of mososauroid reptile Thecachampsa rugosa Emmons (vertebra) Polydectes biturgidus Cope (teeth)
The sharks, Corax falcatus Agassiz and Lamna texana Roemer, are \vide ranging forms, both geographically and stratigraphically, and have no value in correlation. Of the sphyrreoid, Ischyrhiza mira Leidy, ::\Ir. Gidley says: "This species is abundant in the-

GEOJ,OGY OF THE COAS1'AL PLAiN OF GEORGIA.

PJ,.l1' N XI ' JJJ .

A. GULLY lO 'h 1\UJ"ES NORTHEAST OF GEORGETOWN. ROWING COAR E. UNCON OLTDA'l'ED SAND OF 'l'HE PROVIDENCE AND MEMBER OF THF. RIPLEY FOR11ATIOX
B. CU'l' 01~ C. O l? GA. HY.. NE ~llLE o "THEAST OF BUENA , ; IS'l'A. SHOWJN G
UNCO~FORMABLE 0 :\'TA '1' BE'l'WEE ' PROVIDENCE SAND ME~IBER OF n -IE RIPLEY A~D OYERLYING EOCENE.

RIPLEY FORMATION

209

green sand formations of the eastern and southeastern United States
coast, and ranges in time through the Tertiary period."
The two crocodilian species, Thecachampsa rugosa Emmons, and
Polydectes biturgidis Cope, have also been identified by Mr. Gil-
more from Phoebus Landing, Cape Fear River, N. C., an upper
Black Creek horizon. This evidence is therefore corroborative of that
afforded by the fossil invertebrates.
Too little is known of the range of the remainder of the forms
listed to render them of value in correlation.
Fossil plants have been found in the Cusseta member of the
Ripley formation at two localities; one, six miles northeast of
Buena Vista, in Marion County, and the other near Byron, in Houston County. E. W. Berry, to whom the plants were sub-
mitted, recognized from the first named locality six species. Con-
cerning these he says: (Quoted from an unpublished manuscript.)
"Three of the foregoing occur in the underlying Eutaw beds and all but the Ficus, which is new, are found in the Black Creek beds of North and South Carolina. The Andromeda, Araucaria, and Doryanthophyllum, occur in the Tuscaloosa formation, but are confined, so far as known, to the socalled upper Tuscaloosa beds near Havana in Hale County, Ala., although it is probable that the former will be identified from earlier horizons in Tuscaloosa. They are all, moreover, especially characte_ristic species of the Black Creek beds, and the Andromeda is one of the type fossils of the Magothy formation of the northern Coastal Plain, although it makes its earliest ap-
pearance in the Raritan formation, as does also the Eucalyptus. * * *
Concerning those from Byron, he says: "These plants number but three species: Dryopteris sp. nov. Berry, aunninghamites elegans (Corda) End!., and Araucaria jef{reyi Berry, the former being new to science. Since the genus Dryopteris ranges from the Lower Cretaceous to the. Recent and the Georgia species are not closely allied to any described form, it has no value in correlation. Of the other two forms, Ounninghamites elegans has a rather wide goegraphical range occurring both in this country and abroad. Its geological range is also considerable. In Europe it ranges from the Cenomanien to the Senonian inclusive, and in this country it has a parallel range from the Magothy flora of the east to the Montana flora of the west. It has been recorded from Lower Cretaceous horizons in Europe but the latter determinations are believed to be erroneous. The nearest geographical occurrence to th:J.t in Georgia is that of the upper Black Creek beds of North Carolina, hence the conclusion that the exposures near Byron are not older than those of the Magothy or the Black Creek beds appears to be firmly established. "The remaining species, Araucaria jeffreyi, is not a widespread form, but its intimate association, in the Eutaw formation at Chimney Bluff, Ga., and in the Black Creek formation of North Carolina, with Araucaria bladenensis, renders it extremely probably that the former represents the cone scales of a species of which the latter represents the foliage. Taken alone, Araucaria jef{reyi points to the same conclusions regarding the age of the deposits at Byron, as does the distribution of Araucaria bladenensis, but since the latter furnishes more definite data it will be briefly considered. "Araucaria bladenensis is one of the most abundant and typical forms of the Black Creek beds in North and South Carolina, ranging from their base to their summit. It has also been found in the Cusseta member near

210

GEOLOGY OF THE COASTAL PLAIX

Buena Vista, at the top of the Eutaw formation at Chimney Bluff, and at the top of the Tuscaloosa, or in the base of the Eutaw of Smith in western Alabama, while a closely allied form occurs in the MaE:othy of New Jersey."
The eri<le11Ce ~ffordecl by the fossil plants is in harmony, therefore, with that afforded by the fossil invertebrates so far as the correlation of the strata containing them with the Black Creek formation of
the Carolinas is concerned. As regar<l" the I\e,,. ;r er"e; Cretaceous,
ho\rewr, Berry apparently regards the heel" as cmTesponding to a somewhat earlier horizon than that indicated by the invertebratesnamely, to the 2\Iagothy formation_. Howerer, in an unpublished manuscript on the Upper Cretaceous flora of South Carolina he admits the possibility of the ~fagothy flora having persisted to a later time in the Carolinas and Georgia than in N cw Jersey.
Exogyra costata zone.-In the Chattahoochee region the follow.i:rig species, 103 in number, have been identified from the Exogyra costata zone of the Ripley formation:

Gassidulus porrectus Clark

Lima reticulata Forbes (Tp.)

Cassidulus subconicus Clark

Lima acutilineata (Conrad)

Cassidulus conoideus Clark

Lima peLagioa Morton

Oassidulus micrococcus Slocum

Anomia argentaria Morton (Rp. Tp.)

Cassidu!us subquadratus Conrad

Anomia linifera Conrad

Hemiaster ungula (Mortpn)

Anomia sp. nov. (Pataula Creek, etc.)

Hemiaster lacunnsus Slocum

Pa11anomia sea.bra (Morton)

? Coptostoma mortoni (de Loriol) Pulvinites argentea Oonrad

Serpula cretacea (Conrad)

Crenella serioa Oonrad

Serpula barbata Morton

Dreissensia tLppana Conrad

Serpula sp. (nearly straight tube) Pholadomya occidentalis Morton

(Tp.)

Pholadomya 'SP. nov. (Pataula Creek,

Hamulus onyx Morton (Rp. Tp.

etc.)

Hamulus squamosus Gabb

Anatimya anteradiata Conrwd

Nucula percmssa Conrad . (R:p. Tp. Cymella bel1a Conrad (Tp.)

E'b.)

Liopistha protexta Oonrad

Nucula cuneifrons Cnnrad

Cus'pidaria ventricosa Meek & Hayden

Nucula eufalensis Gabb (Tp.)

Veniella conmdi (,Morton) (Rp. Tp.)

Leda pinnaforma Galbb

Etea carolinensis Conrad (Tp. E;b.)

Leda longifrons Cnnrad (Tp.)

Vetericardia crenalirata (1Cbnrad)

Perrisonota protexta Conrad (Tp.) (Tp.)

Cucullaea vulgaris Morton

Crassatellites pteropsis Conrad

Cucullaea littlei Gablb

Crassatellites eufalensis Gablb

I(Jucullaea antrosa Morton

.Scambula per.plana Oonrad

Breviarca cuneata Gablb

Tenea 1pinguis (Gonrad)

Nemodon eufalensis Conrad

SIYhaerella concentrica Conrad

RIPLEY FORMATION

211

Glycymeris subaustralis (d'Orbigny) Cardium eufaulense Conrad (Rp. Tp.)

Gervillio.psis ensiformi's Conrad (Tp.) Cardium spillmani Conrad (Tp.)

Ostrea subspatulata Forbes

Cardium kiimmeli Weller

Ostrea plumosa Morton (R,p. Tp.) Cardium tippanum Conrad

Ostrea tecticosta Grubb (Rp.)

Cardium 'alabamense Gaib'b (Tp.)

Ostrea larva Lamarck

iCiy]primeria depressa Conrad

Ostrea peculiaris Conrad

Cyprimeria alta Conrad (Rp. Tp. Eb.)

Gryphaea vesicularis Lamarck (Rp.) Cyprimeria densata (Conrad) (Rp.)

Exogyra costata S;ay

Aphrodina tip.pana (Conrad)

Exogyra cost'ata var. cancellata

Aenona eufalensis Conrad

Stephenson

Legumen [llanulatum (!Oonrad) (iLp.

Trigoni'a eufalensis Gablb (Tp.)

Tp.)

Trigonia angulieostata Grubb

Linearia metastriata Conrad \Tp.)

Peden quinquecostatus Sowerby Leptosolen biplicata Conrad (Rp. Tp.

(T.p.)

mb.)

Pecten argillensis Conrad

Cymborphora lintea (Conrad) (Rp. Tp.

Pecten simplicius Conr,ad (Tp.)

Eb.)

Pecten tenuitestus Grubb

Corbula crassiplica Gabb (Tp.)

Pecten quinquenarius Conr.ad (Rrp.) Strepsidura interrupta Conrad

Panorpea decisa Conrad

Rapana stantoni Weller

Gastrochaena americana Gabb

Volutomorpha dumansensis Dall

Dentalium rirpleyanum Gabb (Trp.) -:Morea cancellaria Conrad

Cadulus obnutus (Conrad) (Trp.)

Pleurotoma ? melanopsis (Conrad)

Scala sillimani (Morton)

Pleurotoma ? laqueata (Conrad)

Lunatia obliquata Meek & Hayden Ringicula pulchella Shumard

( Tp.)

Cylichna recta Morton

Turritella vertebroides Morton

Nautilus dekayi Morton

Turritella trilira Conrad (Tp.)

Sphenodiscus pleuriseptus (Conrad)

Turritella sp. nov. (two spiral Hamites sp. nov. (same as from

ridges)

Prairie Bluff, etc.)

Pterocerella tippana Conrad

Turrilites alternatus Tuomey

Pugnellus densatus Conrad

Of the 103 species listed, 14, marked (Rp), range dmm into that part of the Exogyra ponderosa zone forming the lower part of the Ripley formation; 30, marked (Tp), occur in the Tombigbee sand member of the Eutaw formation; five, marked (Eb), occur m the basal beds of the Eutaw formation, and 69 are restricted to the Exogyra costata zone.
The ranges of the 69 restricted species clsmvhere in the eastern Gulf region and in the Carolinas and N mv Jersey are given in the following table.

212

GEOLOGY OF THE COASTAL PLAIN

Table showing ranges of species outside the Chattahoochee region which in that region are restricted to the zone of Exogyra costata.

.s "" ..... " ..<; " "0
'S
~s. "p.

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0
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.c
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..=a ~~

'bi !:
..""<'';
" 8

...""-g"".',

,2< ".5

..<;
~

'"" "'" ;o:;;,,
-a
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a.5
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.. ... .eoC~..oo="

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oi;..$.;
"5'i_Sg ~~ ~o~o
~'S
'tj~
t"~'

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.....
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~ "0 ' ~"-...:
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s

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8

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.!L ""0:'':

..".""...,'''
:;.

~... z"

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-5

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>-5 ~
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s":;.' ::";:'

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1. Gassidulus porrectus Clark*.

'

;:;, Cassidulus subconicus Clark*.

3. Cassidulus conideus Clark* .

4. Cassidulus micrococcus Slocum* .

5. Cassidulus subquadratus Conrad 6. Hemiaster ungula (Morton)*

X

X

X

X

7. Hemiaster lacunosus Slocum*

X

8. ? Coptostoma mortoni (de Lorio!)*.

9. Serpula cretacea (Conrad) 10. Serpula barbata Morton*

X

X

X

X

11. Hamulus squamosus Gabb 12. Nucula cuneifrons Conrad*

X

X

13. Leda pinnaforma Gabb

X

14. Cucullaea vulgaris Morton*

15. Cucullaea littlei Gabb*
Hi. Cucu.llaea antrosa Morton

17. Breviarea cuneata Gabb . . . . . -~

18. Nemodon eufalensis Conrad . . . .

I

X

X

X

X
X I

1-

X

X

X

X

X

X

HI. Glycymeris subaustralis ( d'Orbigny)

X

X

X

20. Ostrea subspatulata Forbes* . . . .

X

X

21. Ostrea larva Lamarck

X

X

X

22. Ostrea peculiaris Conrad*

X

23. Exogyra costata Say* 24. Exogyra costata var. cancellata

X

X

Stephenson*

X

X

25. Trigonia angulicostata Gabb*

X

26. Pecten argillensis Conrad

X

27. Pecten tenuitestus Gabb*

X

X

28. Lima acutilineata (Conrad)*

X

X

29. Lima pelagica Morton

x?

X

X

30. Anomia linifera Conrad

X

31. Anomia sp. nov. (Pataula Creek,

etc.)*

X

x?

3') Paranomia scabra (Morton)

X

X

X

33. Pulvinites argentea Conrad*

X

34. Crenella serica Conrad

X

X

X

X

X

X

X

X

x?

X

X

X

X

xl?

X

X

X

X

X

X I

X

X

X

X

X

-

RIPLEY FORMATION

213

.... ~ "".0., '"""

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j, ~

~

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...,., '-"' ~ 'Hc.,..:

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<l>-
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'"' """""' .C~!wJ ...,., !l

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E~
;: Q)

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35. Dreissensia tippana Conrad*

X

36. Pholadomya occidentalis Morton

X

X

X

37. Pholadomya sp. nov. .(Pataula

Creek, etc.)*

X

38. Anatimya anteradiata Conrad

X

X

39. Liopistha protexta Conrad

X

X

xl? X

40. Cuspidaria ventricosa Meek & Hayden

X

X

X

41. Crassatellites pteropsis Conrad

X

X

42. Crassatellites eufalensis Gabb*

X

43. Scambula perplana Conrad

X

X

X

X

44. Tenea pinguis (Conrad)

X

X

X

45. Sphaerella concentrica Conrad*

X

....46. Cardium kiimmeli Weller* Cardium tippanum Conrad*

X

X

X

48. Cyprimeria alta Conrad

X

X

49. Aphrodina tippana (Conrad)

X

X

X

50. Aenona eufalensis Conrad

X

X

51. Panopea decisa Conrad

X

X

X

X

X

52. Gastrochaena americana Gabb

X

X

X

X

53. Scala sillimani (Morton)

X

X

X

54. Turritella vertebroides Morton*

X

X

X

55. Turritella sp. nov. (two spiral ridges*)
56. Pt'erocerella tippana Conrad 57. Pugnellus densatus Conrad

X

x'

X

X

x?

X

58. Strepsidura interrupta Conrad*

X

59. Rapana stantoni Weller

X

GO. Volutomorpha dumasensis Dall* 61. iv'Iorea cancellaria Conrad* 62. Pleurotoma ? melanopsis (Conrad) 63. P!eurotoma ? laqueata (Conrad) * 64. Ringicula pulchella Shumard*
65. Cylichna recta Gabb 66. Nautilus dekayi Morton* ' 67. Sphenodiscus pleuriseptus (Conrad)* 68. Hamites sp. nov. (same as from
Prairie Bluff, etc.)* 69. Turrilites alternatus Tuomey *

X

X

X

X

X

X

X

X

X

I X
X

x' X
X

10ccur only in the Wenonah sand which forms the uppermost formation of the Matawan group. The form from the Wenonah sand referred to Ostrea subspatu!ata Forbes is probably Incorrectly identified.

214

GEOLOGY OF THE COASTAL PLAIN

In the eastern Gulf region to the west of the Chattahoochee region, three of the 69 restricted species occnr in the Tombigbee sand member (Mortoniceras sub-zone) of the Eutaw formation; 12 (one questionably) occur in that part of the Exogyra pondei'Osa zone which lies above the Mortoniceras sub-zone; and 38 ocem in the zone of Exogyra costata.
The Peedee sand (Exogyra cos tata zone) of the Carolinas has furnished a small fauna as compared with that of the zone of Exogyra costata in the eastern Gulf region-the total milnber of species known being 28. Of the U9 species giveH in the above list 18 occur in the Peedee sand, and nine occur in the underlying Black Creek formation. Of the 18 species common to the Exogyra costata zone of the two regions at least nine are characteristic species of that zone. In New .Jersey two of the 69 species occur in the ::\Iagothy formation; 22 (four questionably) in the J\fatawan group; 21 in the Monmouth formation, and two in the Rancocas formation. Of the 21 species common to the Monmouth formation at least seven are regarded as characteristic of the zone of Exogyra costata. The comparison with 'New Jersey is made on the basis of the distribution of species as given by Dr. Stuart \Yeller.1 The percentage of the 69 species common to the Matawan group which is below the zone of Exogyra costata is rather larger than would be expected. However, four of the species are reported only from the Wenonah sand, which forms the uppermost formation of the Matawan group, and it is probable that several of the species are incorrectly identified since obviously many of the specimens upon which the identifications are based are poorly presen-ed.
Of the 69 species restricted to the zone of Exogyra costata in the Chattahoochee region, 38, marked in the table with asterisks, are not known to occur in beds lower than that zone anywhere in the eastern Gulf or Atlantic Coastal Plain. Of the 38 restricted species, 30 occur in the zone of Exogyra costata to the west of the Chattahoochee region in Alabama or MiE'sissippi ; nine (one questionably) in the Peedee sand of the Carolinas, and seven in the Monmouth formation
of New .Tersey.
From the distribution of species as given on preceding pages the following conclusions have been deduced:
The Exogyra costata zone of the Chattahoochee region is the Chattahoochee representative of a paleontologic zone which in western Alabama and east-central Mississippi is represented by approximately the upper one-half of the Selma chalk, and in northern ::\fississippi is represented by the Ripley formation and by a part
1Geol. Survey of Xew Jersey. Vol. 4, Paleontologic series, text and plates, 1907.

RIPLEY FORM4.-TION

215

of the underlying Selma chalk. In the Carolinas this zone is represented by the Peedee sand, and in New Jersey by the Monmouth formation. A diagrammatic representation of these equivalencies is given in Plate V.
The vertebrate remains thus far found in the zone of Eaogyra costata in the Chattahoochee region include the following:

Pisces: Reptuia:

Corax falcatus Agassiz Lamna texana Roemer Otodus sp. ? Ischyrhiza mira Leidy
Tooth of mososauroid reptile Dermal scutes, probably of the preceding form.

Corax falcatus Agassiz, Lamna texana Roemer, and Ischyrhiza rn.ira Leidy are species of wide geographic and stratigraphic range and are valueless in correlation. The ranges of the remaining forms are not known and consequently they throw no light on the age relationships of the deposits.
With the exception of occasional pieces of lignite: fossil plants have been found at bnt one place in the beds under consideration. ,\ few imperfect )eaf remains \vere collected near the base of the zone of Exogyra costata on Cowikee Creek, a few hundred yards above its junction ,,ith Chattahooehee RiYcr i11 11arbonr County, Ala. E. \Y. Berry, who collected and studied these specimens, in a letter to the writer says:

"The fossil plants from Cowikee Creek are few in number and poorly preserved. The following forms are represented:

Bauhinia sp. nov. Platanus sp. nov. Laurus sp.

Salix sp. Sapindus sp. Fern, not determinable

"The remains of the Bauhinia and Platinus are complete enough to dem

onstrate that they are new, the balance are too poor for accurate determina-

tion, although they all appear to be distinct from any forms of the earlier

Eastern Cretaceous floras."



The slight e\idence afforded by these plant remains seems to indicate that a change in the Cretaceous flora of the region took place approximately coincident with the inauguration of the fanna characterizing the zone of Exogyra costata.

21G

GEOLOGY OP THE COASTAL PLAIN

TERTIARY AND QUATERNARY
BY OTTO VEATCH A~D LLOYD WILLIAM STEPHE~SON
EOCENE
MIDWAY FORMATION
NAME
The Midway formation comprises the basal Eocene of the Georgia Coastal Plain. The term Midway was first used by Dr. E. A. Smith' and L. C. Johnson to apply to a formation on the Alabama River in Wilcox County, Alabama. From this locality, it has been traced eastward to the Chattahoochee River, and the strata described by D. W. Langdon' under the name Midway series (Clayton division). The Midway group of Alabama comprises the Clayton limestone, the Sucarnochee clay, and N aheola formation ("Matthews Landing") ; the two latter were not originally included in the Midway group. The upper part of the Midway group of Alabama is apparently missing on Chattahoochee River as the Wilcox formation there rests on the eroded upper surface of Midway strata. The term Midway has received general recognition as a permanent stratigraphic name in the literature on the Coastal Plain geology of Alabama, Mississippi, and Louisiana.
Dr. J. W. Spencer" published some notes on the formation in Georgia and described sections along Flint River. Brief descriptions of a general nature have also been written by McCallie and Veatch.'
DEFINITION
Straligraphic relations.-The Midway formation rests unconformably upon the Upper Cretaceous.. Irregular contacts that appear to represent erosion unconformities between the two divisions were noted, especially in the gullies north and west of Lumpkin, Stewart County. The strata of the basal Midway and the Upper Cretaceous seem to be lithologically similar and on account of inadequate exposures considerable difficulty is experienced in determining the exact location and nature of the contact.
A probable contact between the Cretaceous and the Eocene is exposed in the first railroad cut east of the depot at Lumpkin, where
1Bull. U. S. Geol. Surv. :'olo. 43, 1887, p. 62. 'Ala. Geol. Surv. Rept. on the Geology of the Coastal Plain, 1894, pages 418 to 743. Geol. Surv. of Georgia. First Report of Progress, 1890-91, pp. 43-49. Geol. Survey of Georgia. Bull. No. 15, Underground Waters of Georgia, 1908, pp. 34-35. 'Ge<:>loglcal Survey of Georgia, Bull. No. 18, Clay Deposits of .Georgia, 1909, pp. 79-82.

MIDWAY FORMATION

217

the base of the Eocene eonsists of four to six feet of iron stained clay containing ferruginous sandy layers bearing poorly preserved fossils, resting upon light colored sandy clay of probable Cretaceous age. There is only slight evidence of an unconformity, however. A probable uncomformity was also noted about one and a half miles south of Lumpkin on the Cuthbert public road. Here a ferruginous sand is separated from a kaolinic sand by a line of pebbles and what seems to be certainly Eocene strata appears a short distance to the southward.
In Marion, Schley, and Macon counties the Midway formation lies in contact with the Upper Cretaceous which it closely resembles in lithologic character, but in mapping it is not possible to draw a sharp line between the two. It consists mainly of unconsolidated red, purplish and white sands in which thin, siliceous limonitic layers and crusts and highly ferruginous sandstone are common. Thin beds of impure clays also occur, but neither the clays nor the ferruginous sandstone contain well preserved fossils.
A probable contact between the Upper Cretaceous and the J\'l:idway formation occurs in a cut of the Central of Georgia Railway, one mile east of Buena Vista. The two divisions are separated by thin limonitic layers imbedded in a stained clay. The lower part of the section is white or light colored sand and sandy clay, the upper part, probably representing the Eocene, is a bright red ferruginous sand.
At Underwood Ferry, on Flint River, six miles southwest of Marshallville, Macon County, the base of the bluff consists of gray or yellow rather compact argillaceous sand which contains poorly preserved fossils. From this locality a specimen of Venericardia planicosta was obtained and on the basis of this fossil the strata are classed as Eocene. This is evidently near the northern margin of the Eocene, but the relations to the Cretaceous in this vicinity are obscure. It is also not positively known whether the Eocene represents the Midway or Wilcox.
A gray and black, laminated, sandy clay bearing V enericardia planicosta was also discovered at Barrow's Mill in Houston County, five miles east of Marshallville. There is here a poorly exposed unconformity which may represent a Cretaceous-Eocene contact. Venericardia planicosta and Turritella humerosa were obtained in a similar tiandy clay on Robert Slappy's land, four miles east of Marshallville, The fossils are inadequate for determining whether the exposure is Midway or Wilcox.
No good physical evidence of an unconformity representing a con~iderable time interval between the Cretaceous and Midway has yet

218

GEOLOGY OF THE COASTAL PLAIN

been discovered in Georgia, but there is paleontologic evidence that this intenal is as great here as in adjoining states.
The J\fidway is separated at Fort Gaines from the overlying Wilcox by a remarkable unconformity, which will be subsequently describe<1. Superficial gray and brownish sand is spread over the formation in places and Pleistocene terrace deposits overlie it almig Chattahoochee [;nd Flint rivers.
Lithologic characters.-The 1\lidway is mainly a marine formation and consists of sands, clays, marls, and limestones. Much of the sand, however, has a fresh water aspect. The lower part of the formation consists principally of sands and clays and the upper part consists of marls, clays, and limestones, but there is such variety in the character of the sediments that sharp lines of divisions based upon lithology can not be drawn. Thin layers of flint interbedded with sands and clays were noted in the lower part. The sands are vari-colored, generally friable, and in several places contain lenticular, massive layers of white clay. In the lower part of the formation lim,1nite is rather widely distributed in the sands in the form of thin crusts and as hollow concretions having black, polished, and botryoidal interiors. The limestones are fossiliferous, usually very hard and generally highly arenaceous, but in a few places sufficiently pure for use in the manufacture of lime. Friable marl, made up of glauconite, quartz sand, clay, and shells, occurs, and also laminated, black clay, and fullers earth. The limestones are conspicuous at several localities and are more abundantly fossiliferons than other parts of the formation. Individual beds of limestone in natural exposures are thin, from two or three to 25 feet in thickness, and are interbedded with clays, marls, and sands. Sands and clays make up by far the greater part of the <leposits; the lithologic character and the character of the fossils indicate a very shallow water deposition for the whole form~1tion.
Thickness.-The thickness of the 11id\Yay (referred by -Langdon to the Clayton division of the Midway group, as used in _t\ labama ~: on Chattahoochee River was estimated by Langdon' at 218 feet. The width of the outcrop on the Chattahoochee is about eight miles and it is believed that Langdon's estimate is nearly correct, but it is probtJ bly excessive rather than too small. The thickness of the whole .Midway northeastward is probably greater, and while it can not be accurately estimated, is about 300 to 400 feet. The width of the outcrop on Flint River is about 15 miles and it is not believed that an estimate of 400 feet is excessive. As recorded dips of strata are variable, indiYidual beds not continnons, am1 only a few well data available, no accurate estimate is possible.
'Langdon. D. W.. Geology of the Coastal Plain : Geol. Survey Alabama, 1894, p. ,36!1.

MIDWAY FORMATION

219

Paleontologic characters.-The collections of fossils from the format~on_ are on the w~ole rather meage~. Thi~ is due to a paucity of fossils m the formatiOn rather than to msuffiCient field work, since all of the best known exposures have been visited. Ostrea crenulirnargin_ata seems to be a characteristic fossil and is found at nearly every hmestone and ~arl outcrop. The basal part, which consists mainly of sands and clay, is very poor in fossils. Venericardia planicosta, Turritella, and other forms occur, bnt these are common to other Eo-
cene formations. One of the characteristic fossils of the formation in Alabama, Enclirnatoceras ulrichi, has oot thus far been found in Georgia. The following is a complete list of the forms which haYe been identified.

Fossils from the Midway Formation in Georqia.

Turritella mortoni Oonrad Turritella humerosa Conrad MesaUa alaJbamiensis (Whitfield) Area sp. Ostrea crenulimarginata Ga;bb Ostrea pulaskensis Hards Lithodomus gainesensis Harris

OrassateUites Venericardia planicosta Lamarck Venericardia smithii Aldrich Cardium sp. Protocardia sp. Cytherea ripleyana (Gabb)

The determinations are by Dr. V anghan from collections made by \reatch, McCallie, and Stephenson.
A fossil turtle, Agornphus oxysternum, has been found in the J\Iidlray near J\Iontez~m1a. The specimen was first described by Cope' and later by Hay.

Areal distribu,tion.-The ~lidway occurs in a narrow belt, having a northeast southwest trend, extending from Fort Gairtes on Chattahoochee River to Montezuma on Flint Ri\er and thence a short distance into Houston County. On the Chattahoochee it reaches a width of about eight miles and on the Flint a width of about 15 miles, while between the hvo rivers the belt has an average width of eight to ten miles. 1t is the surface formation over much of Clay, Quitman, Stewart, Randolph, Marion, Schley, \Vebster, and Macon counties. It extends eastward from Flint River into Houston County, probably as far as Myrtle on the Perry branch oi. the Central of Georgia Rail. way. No occurrence is known east of the Ocmulgee RiYer. 1n this area it is probably overlapped by higher Eocene formations.

Physiographic expression.-The topography of the area underlain hy the Midway is broken and hilly, somewhat similar to the Creta-

'Proc Anwr. Phllos. Soc.. VoL 17, 1877, p. 82. 'Hay: 0. P .. Fossil Turtles of -:\'orth America: Carnegie Institution, 1908. p. 2::i~.

220

GEOLOGY OF THE COASTAL PLAIX

ceous area to the northward, and in contrast to the level topography d the areas.. to the southward underlain by Claiborne aul Oligocene strata. A few lime-sinks occur in the vicinity of Fort Gaines and north of Cuthbert.
Structure.-The formation presents no notable structural features. It has a low southward dip in conformity with the general southward inclination of all of the older Coastal Plain formations. No data for accurately determining the dip are at hand, on account of the discontinuity of exposures of individual beds. Recorded dips show wide variations due to local disturbances of the strata.
The dip of the formation, as a ~whole, is roughly estimated at 20 to 30 feet per mile. It is, however, unlikely that this rate of dip is maintained southward under cover of later formations, since Cretaceous fossils, Anomia argentaria' and Exogyra costata, were found in the borings of an artesian well at Albany at 890 and 1,100 feet, respectively, and the base of the Midway according to these fossil determinations might be even above the 890-foot level (for a log of this well see page 317). Local crumpling of clay beds and local very Ligh angles of dip were noted, especially in Stewart, Randolph, and Quitman counties. These may be results of movements which produced the Chattahoochee anticline.
Economic geology.-Limestones and marls of the formation should be of some local value as fertilizers, lime, and road materials. There has been, however, but small utifization of these materials. Localities where they are to be found are mentiond on succeeding pages. The formation contains beds of white fire-clay which may be of some future commercial value. Beds of considerable thickness and extent were found in Quitman, Stewart, :Marion, and ~1:acon counties. Limonitic iron ore is widely distributed throughout the lower part of the formation, and at a few places is perhaps of sufficient extent to be of commercial value.

LOCAL DETAILS
Fort Gaines.-Limestone of the Midway formation is protr.ineutly exposed in the river bluff at Fort Gaines, and at the old Erow:n Mill on Comochechcbhe Creek, one mile north of the town. Itt-; fir,;L known appearance on the Chattahoochee is at a point sever. miles above Fort Gaines, near :Morris Landing, on the Alabama side of the river. At this locality Turritella mortoni is very abundant. There are also V enericardia planicosta and other fossils, poorly preserved and not positively identifiable. The material is a greenish, rather
'Determinations made by L. W. Stephenson.

MIDWAY FORMATION

221

calcareous sand. Five miles above Fort Gaines is an exposure of rock, massive-bedded, white, earthy, or chalky in appearance; in texture it is both hard and compact and pulverulent or marly; it contains a high percentage of quartz sand and varies from sandy limestone to a calcareous sand. The limestone at Fort Gaines is poorly fossiliferous; Ostrea pulaskensis and Lithodomus gainesensis were collected; Bryozoa and small echinoids also occur in it. A maximum of 30 feet of the limestone is exposed in the river bluff at extreme low water. The limestone is best exposed on the Georgia side at the wagon bridge and at a point about 350 yards below the bridge, where a striking unconformity appears between it and the overlying strata. Circular pockets of black, sandy clay occur in the limestone and are probably pot holes, 20 feet or more in depth, which were filled during the deposition of the strata overlying the limestone.
The section exposed at Brown Mill, one mile north of Fort Gaines is as follows :

Section at Brown Mill.
Pleistocene. 3. Red and yellow pebbly sand . .
Eocene. Wilcox formation. 2. Glauconitic sand and friable shell marl (Unconformity.) Midway formation. 1. Soft, massive-bedded limestone . . . .

Feet. 5
6
0 20

The limestone here is soft, white, mas'sive bedded and sandy, resembling that exposed in the river bluff. The exposures also reveal the same remarkable pot-hole unconformities which are present on the river. Fragments of Bryozoa, 0. pulaskensis, and a small echinoid were collected. The limestone appears in the banks of the creek to about one-half mile above the mill. The continuation of the limestone for at least a short distance northeastward is indicated by lime-sinks. However, the unbroken continuity of this limestone bed northeastward has not been demonstrated. The limestones at Greer Cave, Preston, Quebec, and J\ontezuma, which are supposed to be equivalent in age to the limestone at Fort Gaines are entirely unlike it in lithologic ~p pearance, and evidence of a limestone bed connecting these localities, which would be afforded by outcrops and the character of the soil, is entirely wanting.

Hatcher.-On the Griffith plantation, four miles south of Hatcher
Station, there is an exposure of 20 feet of limestone and marl. This locality is the site of the old Redding mill and lim~-kiln. The rock ''aries from marl throngh extremely hard, calcareous quartzite to com-



222

GEOLOGY OF THE COASTAL PLAIN

paratively pure compact limestone; it resembles the limestone at Greer Cave and Preston, but differs somewhat in its lithologic appearance from the limestone at Fprt Gaines. The rock contains Ostrea crenulimarginata, a characteristic fossil of the Midway, and also a smaller species of oyster, probably 0. pulaskensis. The area of natural exposures is small and attempts to locate outcrops between this locality and Greer Cave in Randolph County ~were unsuccessful. The oYerlying stratum is red, argillaceous sand.
The exposures in the Central of Georgia Railway cuts northwest of Hatcher, Quitman County, generally show variegated sand, coarse grained, often kaolinic and micaceous, resembling some of the beds of the Lower Cretaceous. The sands contain pockets of white and stained clays associated with limonitic crusts and hollow concretions. At mile-post 139, thin, limonitic crusts, from a few inches to a foot or two thick, containe.d casts of fossils, Dendrophyllia, V enericardia planicosta, Yenericardia smithii, Cytherea, which are Eocene fossils, and a specimen of the Cretaceous genus, Pugnellus. At this locality there is a mixture of Eocene and Cretaceous forms. It is probable that the crnsts were originally glauconitic sand, since grains of glauconite partially altered to limonite still remain. Also, near milepost 135, there is an exposure showing 30 feet of yellow, brown, and umber colored, stiff clays, mixed with harsh, gritty, or angular sand. The clay layers here are crumpled and disturbed from their original positions. The same general lithologic characters persist eastward to Flint RiYer in the lower part of the formation. The strata exposed south of Lumpkin are mainly crossbedded quartz sands, containing thin white clay layers; brownish, g-lauconitic clays, fullers earth, and thin beds of flint were also observed.
Beds of flint which are probably J\fidway, occur near the gin-house of \V. \V. Greene, one and one-half miles southwest of Georgetown station. These rocks appear to have been derived by silicification from limestone similar to that at Fort Gaines. The rock lies in the ~scarpment of the second terrace bordering Chattahoochee River. Similar thin beds of flint have been observed near Beatrice, eight miles southwest of Lumpkin; on the Jones plantation, nine miles southeast of Lumpkin; five miles west of Richland; and at Bells ~Till near
Preston. Dr. Y anghan has supplied the following notes:
"At several localities at which Mr. Veatch made collections, fossils are so scarce and those obtained are so poorly preserved, that positive stratigraphic determinations are not possible.
"Ostrea pulaskensis and the cast of the interior of an Area, probably the same as the unidentified specimen figured by Professor Harris in his monograph on the Midway, were obtained at the base of the bluff at Fort Gaines. This exposure is definitely known to be Midway.

MIDWAY FORMATION

223

"The imprint of an Area, probably belonging to the same species as the one from the Midway just referred to, and a Barbatia, referr.3d by Professor ~arris in his monograph on the "Lignitic" to B. cuculloides (Conrad), were found on W. W. Greene's plantation, one and one-half miles southwest of Georgetown. A careful comparison with B. cuculloides from the Jackson and Vicksburg in the National Museum leads me to the opinion that Professor Harris has probably allowed too much latitude in variation. It can not be determined from the fossils whether the horizon is Midway or Wilcox.
"An oyster, which appears to be 0. pulaskensis Harris, and specimens representing at least two species of echinoids, were obtained on the Jones plantation, nine miles southeast of Lumpkin. This exposure is probably Midway.
"Ostrea, probably pulaskensis, and two species of echinoids, one of which
is either the same as, or very close to one of the species found on the Jones plantation, were collected at the 105th mile-post of the Seaboard Air Line Railway, five miles west of Richland. The geologic horizon of this expoeure is probably Midway.
"In the vicinity .of Bells Mills, four and one-half miles northeast of Preston, poorly preserved fossils were obtained at several localities. Among them are Cardium, venericardia, Leda, probably pharcida Dall, and an oyster suggesting 0. thirsae. If the oyster is really 0. thirsae, it indicates that the Wilcox overlapped the eroded surface of the Midway. However, the information at present available does not warrant a positive opinion."

Greer Cave locality.-At Greer Cave, nine miles north of Cnthhert, on the upper Lumpkin road, there is an exposure of 30 feet of hard, gray, rather fine-grained, fossiliferous limestone. Most of the rock is comparatively pure, but near the base of the exposure it becomes very sandy and can be properly tm;med .a calcareous quartzite.
An exposure occurs in the public road one mile south of the above locality. The rock here is compact at the base, grading into a gray or light yellow friable shell marl, and gray calcareous sand. A dark red, clayey sand overlies the marl and may be, in part, residual. The height of the hill here is. 70 feet, the lower 30 feet being marl and limestone. The formation at this locality contains characteristic :Midway fossils, and is one of the most notable lower Eocene exposures.

Preston.-Midway limestone or marl appears at Lime Spring, on the Cole property, on the south side of Kinchafoonee Creek, t>vo miles southeast o:f Preston. The rock is a hard grayish limestone or indu .. rated, argillaceous marl, merlain by ferruginous sand. About 15 feet is exposed in the hiilside which forms the swamp bluff.
The rock is fossiliferous, but ~rood fossil specimens are rather difficult to obtain. Dr. Vaughan has identified the following fossils from this locality:

Fossils from Lime Spring.

Turritella humerosa Conrad Mesalia alabamiensis (Whitfield) Ostrea pulaskensis Harris?

Ostrea crenulimarginata Gabb Protocardia sp. Crassatellites sp..

At a point one mile south of Preston on the \Veston road then 1~ a thin bed of flint from which Dr. Vaughan has identified: Tm-

224

GEOLOGY OF THE COASTAL PLAIN

titella> Ostrea apparently thirsae (Gabb), and Venericardia. It is very probable that tnis bed lies beneath the marl on Kinchafoone~ Creek and is hence Midway.' A marl, that occurs in the bed of the creek at the old Harrell distillery, about one mile farther south, is similar to that at Lime Spring and contains Ostrea crenulimarginata (?).
At Bell's Mill, four and a half miles northeast of Preston, Dr. Vaughan has identified, Ostrea thirsae, Leda pharcida, Dentaliurn, Cardium> Lucina. The fossils were collected from thin flint beds. The geographic position of the beds, (four or five miles north of the Midway at Lime Spring on Kinchafonce Creek) their low topographic position, (lower than the higher ridges and hills of this vicinity, with no suggestion of an overlap), are considered evidence that the strata here may belong to the Midway.

Ellaville.-Near the site of old Quebec, eight miles southwest of Ellaville, there is an exposure of 20 feet of highly siliceous limestone and clay with siliceous nodules, overlain by red, highly ferruginous sand and sandstone. The rock here might be properly termed a calcareous grit. Large angular, crystalline quartz grains are imbedded in a white, opaque and enamel-like calcareous matrix. The rock is very hard and compact and the quartz g-rains fracture rather than fall out when the rock is broken; the compactness is due in part to a cement of amorphous or opaline silica. Oyster shells, Ostrea crenulima"'r;inata, were observed. The rock contains a small amount of phosphate in the form of brown gTains or pellets.
At Walls Crossing, four and one-half miles northwest of Ellaville, Midway fossils were collected from a thin marl bed. The marl and limestone bed which is about four feet thick is exposed at the head of a small branch about 200 yards northwest of the cotton gin of Mr. C. H. Wall. Dr. Vaughan has identified the following fossils from this locality:

Fossils from Walls Crossing.

Turritella humerosa Conrad Turritella alabamiensis Whitfield Ostrea crenulimarginata Gabb.

Venericardia smithii Aldrich Cytherea ripleyana (Gab:b)

Montezuma.-Good exposures of the Midway formation appear in the bluffs of Flint River above and below Montezuma. The following section appears in the bluff at the wagon bridge one mile northwest of the town :

1See note by T. W. Vaughan, p. 222.

MIDWAY FORMATION

225

Section one mile northwest of Monte~uma.

Pleistocene (terrace deposit).

6. Red sand with a covering of brown, incoherent

Age ?

superficial sand . . .

5. Laminated, drab clay . . . . . . . . . . . . . . . Eocene.

Midway formation.

4. Compact limestone, variable thickness; contains

large oysters . . . . . . . . . . . . . . . . . .

3. Clay, marl and limestone . . . . . . . . . . . .

2. Massive limestone layer, contains 0. crenulimargi-

nata, Cardium, Orassatellites . . . . . . . . .

1. Bluish, massive bedded clay and coarse gritty ar-

gillaceous sand . . . . . . . . . . . . . . . .

Feet.
15 to 20
2 8 5 15

Northward from the bridge, No. 1 reaches a thickness of 25 feet; the lower end of the blufi is not well exposed and fragments of beds Nos. 2 and 3 have fallen to the base. The dip of the strata is southward, and bed No. 5 doubtless dips beneath the river between the upper wagon bridge and the Central of Georgia railroad bridge.
At a locality two and a hal miles north, and on the east side of the river, on the De Yaughn plantation, the following section occurs:

Section on De Vaughn plantation.

Feet.

5. Red, argillaceous sand capping bluff . . . . . .

4. Clay with nodules of limestone, oyster shells abundant;

the materials are weathered and not well exposed . . 8

3. Compact, gray, sandy limestone, fossils

. 3

2. Friable, calcareous, gray, clayey sand . . . . . . . . . . 10

1. Sandy, glauconitic limestone . . . . . . . . . . . . . . . 20

Another section ,exposing limestone occurs at Dripping Blufi, nine miles south of Oglethorpe. Tpe limestone is compact, bluish-gray, glauconitic and fossiliferous, containing the characteristic Midway oyster, 0. crenulimarginata and other fossils. Dripping Blufi is on the west side of Flint River and about half way between the mouths of Sweetwater and Camper creeks.

Section at Dripping Bluff.

Pleistocene (terrace deposit)

Feet.

12. Reddish sand poorly exposed . . . . . . .

12 to 15

Eocene.

Midway formation.

Feet. In.

11. Poorly exposed and partly concealed, but probably

calcareous clay, containing limestone nodules . 10

10. Interbedded, very thin layers of hard, nodular

limestone and clay

5

9. Clay . . . . . . .

1

8. Limestone . . . .

8

7. Black clay marl . .

1

226

GEOLOGY OF THE COASTAL PLAIN

Feet. In.

6. Nodular limestone and black argillaceous sand . 1

5. Clay marl . . . . . . . . . . . . . . . . . . . . 2

4. Limestone . . . . . . . . . . . . . . . . . . . .

6

3. Black, compact, argillaceous sand . . . . . . . 22

2. Hard, pitted, sandy and glauconitic limestone;

contains fossils, principally large 0. crenuli-

marginata . . . . . . . . . . . . . . . . . . . [l

1. Black, argillaceous sand and sandy marl, not ex-

posed except at low water . . . . . . . . . . . 3

Bed No. 2 is apparently dipping soutlmard at the rate of about 30 feet per mile.
The following is a section of a bluff one-fourth to one-half mile above Dripping Bluff.

Section one-half mile above Dripping Bluff.
,4. Red and crossbedded, rather coarse sand with small quartz pebbles at the base. This material underlies a terrace 'Plain 45 to 50 feet above the river, and is doubtless Pleistocene . . . .
Midway formation 3. White and red fine sand, containing clay laminae 2. Black, massive, pyritiferous argillaceous sand, yellowish at the top, with thin limonitic crusts . . 1. Massive bluish-white, jointed clay . . . . . . . .

Feet.
12 7
10 14+

Bed No. 2 contains a few poor fossil prints. X o marl or limestone appears; this indicates the variable nature of the J\!Iidway deposition. Furthermore, no limestone or even calcareous strata have been observed between this point and the bluff at :Montezuma. A clay bed very similar to No. 1 of the preceding section occurs at Copperas Bluff, about three miles farther dmvn-stream.

Section at Copperas Bluff.
Pleistocene (terrace deposit). 3. Yellow and orange sand, variable thickness, maxi mum ..
Eocene. Midway formation ? 2. Black, pyritiferous, massive argillaceous sand, contains a few prints of fossils . . . . . . . . . . 1. Massive, jointed, bluish-white clay, maximum thickness . . . . . . . . . . . . . . . . . . .

Feet. 20
15 15

Beds 1 and 2 are almost identical lithologically with Nos. 1 and 2 of the 'above section.

WILCOX FORMATION
NAME
The Wilcox formation derives its name from wilcox County, Alabama, where the formation is typically exposed. Strata of this for-

WILCOX FORMATION

227

mation were formerly embraced in the "Lignitic Group." Dr. E. W. Hilgard1 used the term "Lignitic" in Mississippi or all o the strata lying between the Claiborne and the Cretaceous, and included in it come beds belonging to the Claiborne group. Also in early literature' the term was applied to all o the formations lying between the ''Burhstone" and the Cretaceous o Alabama. Subsequently; however, the calcareous beds at the base o the Tertiary in Alabama were differentiated and given the name Clayton (a division o the Midway). The term "Chickasaw" was later substituted or "Lignitic", excluding the Flatwoods belt o Mississippi, by Dr. Hilgard and Dr. Dall, and by a still later decision o the committee on nomenclature o the U. S. Geological Survey,' the name Wilcox was substituted or that portion o Hilgard's "Lignitic", which lies below the Claiborne group and above the Midway.
D. W. Langdon studied strata o the Wilcox on the Chattahoochee River and made the following divisions:

Hatchetigbee

Lignitic Bashi (Woods Bluff)



{

Tuscahoma Nanafalia

(Bell's Landing)

These divisions can not be discriminated eastward rom the ChattahDochee.
In view o the small thickness o the Wilcox at Fort Gaines, and the probable occurrence o strata o the Claiborne group on Chattahoochee River near water-level our miles south o Fort Gaines (see following pages), it is not unlikely that a portion o the strata classed as "Lignitic" by Langdon, belongs to the Claiborne.

DEFINITION
Stratigraphic relations.-In Georgia, the Wilcox ormation includes the strata lying between the Midway ormation and the Claiborne group. At Fort Gaines on Chattahoochee River, the Wilcox and the Midway are separated by a remarkable erosion unconformity, represented by holes in the white limestone o the Midway ormation filled by black sandy clay o the overlying ormation. These holes must originally have had a depth o 20 eet or more. Paleontologic and lithologic differences and the erosion unconformity furnish a sufficient basis or the separation o the Midway and Wilcox formations

1Hilgard. E. W., Geology and Agri~ulture of Mississippi, 1860, p. 108. 'Smith, E. A., and Johnson, L. C., U. S. Geol. Survey, Bull. 43, p. 38. 'Geol. Surv. of Ala., Report on the Geology of the Coastal Plain, 18\!4, p. 147. 'Crider, A. F., Geology and Mineral Resources of Mississippi, U. S. Ceol. Survey, Bull. 283, p. 25.

228

GEOLOGY OF THE COASTAL PLAIN

at Fort Gaines. East of this locality, however, the paucity of the :fossils, the fact that no unconformity could be discovered, and the unsatisfactory character of the evidence' furnished by the lithologic composition of the strata, has rendered the discrimination of the two formations very difficult; therefore, the boundary line as mapped is necessarily tentative.
The contact with the overlying Claiborne group, where this has been observed, is marked by an undulating line of small pebbles or a stratum of coarse sand, but there is no physical evidence of any considerable time interval having elapsed between the deposition of the two. An unconformity marking the contact between the Claiborne group and the Wilcox formation has been noted at the following localities: in the bluff at Fort Gaines, 50 to 55 feet above Chattahoochee River; in a cut of the Central of Georgia Railway two and one-half miles west of Cuthbert; at Hall's Bridge on Kinchafoonee Creek seven miles southwest of Plains ; doubtfully in the public road at Blacks Mills five miles north of Plains; and one and one-half miles southeast of Andersonville, on the south side of Sweetwater Creek, about one mile below Hodge's Mill. Unfortunately, the strata are not fossiliferous, except at Fort Gaines, and the evidence that the unconformities are of stratigraphic importance is not entirely conclusive.
Lithologic characters.-On Chattahoochee River, the formation is made up of sandy, glauconitic, shell marl, dark colored, laminated, often lignitic, sandy clay, in places consolidated into mudstone, and usually dark or gray glauconitic and lignitic sand. The laminated clay exposed in the bluff at Fort Gaines can be traced northeastward, having in Randolph County north and west of Cuthbert, the nature
of fullers earth, which in places is glauconitic. At Greer 'Cave,
there seems to be a considerable thickness of vari-colored and kaolinic sand between the Wilcox clay and the limestone of the :Midway formation. Black and drab laminated, glauconitic clay and sand were observed on Bear Creek northeast of Weston, Webster County. Gray and black argillaceous and glauconitic sand appears at Magnolia Spring, two and one-half miles north of Plains; in the bed of a branch on the old Morgan plantation, six miles northeast of Plains; and at Hall's Bridge on Kinchafoonee Cr:eek, seven miles southwest of Plains. Farther eastward in Schley and Macon counties and in the vicinity of Andersonville, the strata which might be referred to this formation on the basis of geographic position, are mainly red and varicolored sands with massive beds of white clay, very pure and in the nature of sedimentary kaolin, bearing little resemblance to the strata on Chattahoochee River.

WILCOX FORMATION

229

Thickness.-It seems very probable that Langdon's1 estimate of 402 feet is excessive, in view of the small thickness of Wilcox at Fort Gaines, and from the fact that Dr. Vaughan has determined Exogyra costata from the Blakely well at a depth of 500 to 510 feet. (See page 312). The thickness of strata between the McBean and the Midway formations at Fort Gaines does not exceed 75 feet. The maximum thickness at any place over the area of outcrop probably does not exceed 150 or 200 feet. It is difficult to form an accurate estimate of the thickness of the Wilcox formation as is true also of the underlying Midway formation, for east of Chattahoochee River, neither the base nor the top of the formation has been accurately established. There is a natural exposure of the formation revealing an estimated thickness of 100 feet of strata at Peterson Hill, four and a hal miles northwest of Cuthbert. The following is the record of a well at Shellman, Randolph County:

Record of well at Shellman.

5. Red clay . . . . . . 4. Quicksand . . . . . 3. Blue marl . . . . . 2. Very hard limestone . . 1. Water bearing formation

Feet. 0 to 1& 1& to 14& 148 to 300 300 to 400
400 to 410

Assuming the limestone layer No. 2 to be the same as the Midway limestone which is exposed at Greer Cave about 16 miles northwest, the overlying 152 feet of "blue marl" may belong to the Wilcox formation.
There is no positive proof of strata of Wilcox age on Flint River. It may be entirely overlapped by the Claiborne, but assuming that the strata lying between the Midway formation at Dripping Bluft (see page 225) and the McBean or Vicksburg formations is Wilcox, the thickness is perhaps 100 feet.

Paleontologic chariwters.-The formation is on the whole poorly fossiliferous. The following Georgia forms have been identified by Dr. Vaughan from collections made by the writer east of the Chattahoochee. River:

List of fossils from the Wilcox formation in Georgia.

.A!ctaeon Turritella mortoni Conrad Turritella !Praecincta Conrad

Ostrea thirs,ae (Gabb) Venericardia planicosta Caroium

1Langdon, D. W., Report on the Geology of the Coastal Plain, Ala. Geol. Survey, 1894.

p. 369. McCallie,

s.

W.,

Underground

Waters

of

Georgia,

Bull.

15,

1908,

p.

156.

230

GEOLOGY OF THE COASTAL PLAIN

C.alyprtrea ,aperta ('Solander) Denrtalium Leda pharcida Dall Glycymeris

Proto-cardia Cytherea Cassidulus ( ?) sp.

At a locality five and one-hal miles south o Lumpkin the following fossils were obtained:

Fossils from five and one-half miles south of Lumpkin.

Endopachys maclurii (Lea)1 Pyrula juvenis Whitfield ? Turritella sp. Leda (ap;parently rpharcida Dall) Cytherea nurtalliopsis Heilprin ?

Nucula sp. Paracyathus ? sp. Cucullaea macrodonta Whitfield Lucina sp.
Cytherea sp.

The species 0. thirsae, 0. compressirostra, Chlamys greggii, and Cucullaea macrodonta have been identified rom beds near Fort Gaines. Dr. Vaughan has also identified a small oyster as 0. thirsae, a species considered characteristic o the Wilcox ormation, rom beds our and one-hal miles northeast o Preston, and a specimen apparently 0. thirsae rom a flint bed one mile south p Preston. There, is however, a possibility o these beds belonging to the Midway. As the collections are small and the material in general poorly preserved, oten stratigraphic deductions rom fossils can not be made with the same surety or Georgia as or states to the west where fossils are more abundant and better preserved. Further mention o the material near Preston and a note by Dr. Vaughan will be ound on pages 222-223.

Areal distribution.-The Wilcox ormation extends in a northeastward direction rom the vicinity o Fort Gaines on Chattahoochee River probably to Flint R~ver in the northeastern part o Sumter County. The width o the belt o outcrop is on the average perhaps not more than five or six miles. It is, to some. extent, overlapped and obscured by the McBean and Vicksburg formations. The ormation has not been recognized east o Flint and Ocmulgee rivers. Pro. G. D. Harris referred strata at Roberts, nine miles east o Macon, to the horizon o the "Woods Bluff" (Bashi), ormation o the Wilcox group, but it seems now more probable that they are Claiborne. (See page 279.)
Physiographic expression.-The area underlain by the ormation is small and it has produced no notable physiographic features. The topography o the area is rather broken and hilly similar to that o the Midway area to the north.
, 1Note by Dr. Vaughan: "Endopachys maclurii suggests Claiborne; while Oucullaea macrodonta is usually not later than Wilcox."

WILGOA'; FORMATION

231

Structure.-The strata dip southward or southeastward. No dat:.t are at hand for accurately estimating the rate of this dip. It is probably less than 30 feet per mile. No evidence of local deformation was. noted, although, doubtless, such may have taken place-in the area adjacent to Chattahoochee River, as noted in the case of the Midway formation.
Economic geology.-Friable, glauconitic shell marl occurs at the base of the Wilcox formation at Fort Gaines, and should be of local value as a fertilizer. This marl, in addition to calcium carbonate, carries small percentages of phosphoric acid and potash. Massive beds of white, fire-clay, which probably belong in this formation, occur in the northern part of Randolph County and in Schley and Sumter counties and will probably be of some commercial value in the future.
LOCAL DETAILS
Fort Gaines.-The Chattahoochee River bluff at Fort Gaines, Clay County, affords exposures of great stratigraphic importance. Sections of the bluff have'been published by Loughridge/ Spencer," Langdon' and Veatch.' Sections made by different observers differ in details, from the fact that the layers are of somewhat variable lithologic composition.
The following is a section made by Dr. Stephenson:

Section of bluff on Chattahoochee River at Fort Gaines, Ga.

Pleistocene (terrace deposit). 12. Coarse, red, ferruginous sand, pebbly in lower half 11. Pebble and cobble layer, the pebbles and cobbles well rounded; also numerous fragments of greenish, gray, calcareous sandstone . . . . .
Eocene. McBean formation. 10. Greenish gray, laminated clay with, fine sand partings, and occasional thin layers of glauconitic sand ..................... . 9. Very glauconitic sand with irregular iron concretions ..................... . 8. Indurated layer of large oysters with sand matrix. Contains also large prints of Venericardia planicosta, and in loose glauconitic sand pockets along base small fragile pectens. (Fossils col-
lected . . . . . . . . . . . . . . . . . . . . . 7. Light gray, calcareous sand with small scattered
fragile shells . . . . . . . . . . . . . . . .

Feet. 18 2
8 10

'Tenth Census, Vol. VI, Cotton Prt~duction, Georgia, p. 14. 2Spencer J W., First Report of Progress, Geol. Surv. of Ga., 1890-91, p. 46. Landon,' D: W., Report on the Geology of the Coastal Plain, Ala. Geol. Surv, 18!!4, p. 4V0e6a.tch, Otto, Clay Deposits of Georgia, Geol. Surv. of Ga. Bull. 18, 1909,. p. 8""

232

GEOLOGY OF THE COASTAL PLAFX

6. Indurated layer of argillaceous, calcareous sand-
stone with a few prints of fossils . . . . . . . Wilcox formation.
5. Dark gray, calcareous rather coarse argillaceous sand, with scattered lime- concretions . . . . .
4. Dark gray, more or less sandy clay with pockets of sand . . . . . . . . . . . . . . . . . . . .
3. Dark gray shell marl with rather coarse sand matrix. Lime concretions irregularly distributed through the marl, especially near the mid' dle of the bed. <;ontains numerous large pieces of lignite also near the middle of the bed. Shells most numerdus 8 to 10 feet above base of section. (The horizon is the same as that from which a collection was made on the west side of river above the bridge at Fort Gaines) . . . .
2. Light gray, mealy, very micaceous sand, streaked with iron stain. (This stratum and the preceding separated from the following bY a marked unconformity) . . . . . . . . . . . . . .
Midway J'ormation. 1. Rather soft, yellowish limestone (stage of water about eight feet above normal) . . . . . . . .

2 12 13
17 to 20 0 to 4 3 to 10

From Layer No. 8, Dr. Vaughan identified 0. sellceformis, Pecten deshayesii, and 0. georgiana ?, and determined the horizon to be Claiborne.
A ~ection and description which includes some details not given in the preceding sections was made by Veatch. The location is about one-fourth mile below the wagon bridge.

Section of Bluff at Fort Gaines.

Pleistocene (terrace deposit) 13. Coarse red sand with quartz pebbles in the lower half; caps the bluff . . . . . (Unconformity).
Eocene McBean formation. 12. Drab, fine-grained, laminated clay with sand part-
ings . . . . . . . . . 11. Yellow and grayish glauconitic sand . 10. Clay and sand, in part calcareous
9. Indurated clay layer or drab claystone; contains fossils and is similar lithologically to the Claiborne claystone east of the town of Fort
Gaines .. 8. Grayish, argillaceous sand 7. Yellowish and gray quartz sand; contains calcarll-
ous sand nodules; small pebbles noted at the base; fossils Xenophora, Venericardia planicosta
wilcox formation. 6. Gray and black laminated, sandy carbonaceous clay; part of the thickness is indurated and
jointed . . .

Feet. 15
8 10 to 12
20
2 to 2lh 6
2 to 2lh
18

WILCOX FORMATION
5. Calcareous, compact, argillaceous sand, contains fragile shells and is in the nature of a marl; Balanophyllia . . . . . . . . . . . . . . . . .
4. Nodular calcareous layer . . . . . . . . . . . . . 3. Ash-colored, lignitic sand, unconsolidated bed of
small oyster shells, 0. thirsae, at the base . . . 2. Gray, mealy, lignitic sand, variable thickness, in
erosion pockets in limestone . . . . . . . . . (Unconformity.)
Midway formation. 1. White to yellowish soft massive bedded limestone poorly fossiliferous, contains 0. pulaskensis, maximum thickness exposed . . . . . . . . .

233
8 2 7 4
20

At very low water stages, circular pockets of black, or gray lignitic, argillaceous sand can be seen in the limestone in the bed of the river beneath the wagon bridge.
No. 13 of the section underlies the terrace plain upon which Fort Gaines is situated, and is a Pleistocene terrace deposit.
In the west bank of the river at the wagon bridg, the white sandy limestone of the Midway formation is overlain by three to six or eight feet of friable, sandy, glauconitic marl, in which the shells of the small oyster, Ostrea thirsae, are very abundant. Above the marl there is a sandy clay which contains white calcareous nodules.
At the mill and cotton-gin on Commochechebbe Creek, one mile north of town, the Midway-Wilcox unconformity is again well exposed. A lignitic, argillaceous sand fills holes and cracks in the limestone, and the limestone is overlain unconformably by a glauconitic sandy marl which contains in abundance small oyster shells, 0. thirsae, small fish teeth and fragments of bones.
At the mouth of Flat Creek, four and one-half miles south of Fort Gaines, a glauconitic, sandy argillaceous, shell marl was found in the bed of the creek a few yards above its junction with the river. The creek has cut a narrow trench in the first terrace bordering the river, formi}\g bluffs about 30 feet high. Only two or three feet of marl is exposed above the water, and the upper part of the bluff is a dark, lignitiferous, argillaceous sand, and Pleistocene alluvium. From fossils collected here, Dr. Vaughan has identified:

Cucullaea macrodonta Whitfield Ostr,ea comvressirostra Say. Chlamys greggii Harris

Pecten sp. Ostrea sellaeformis Conrad

The 0. sellmforrnis suggests Claiborne strata at this point, while the other fossils are Wilcox in age. However, no other evidence of two Eocene horizons was observed in the field examination. The evi<!ence of Claiborne age afforded by 0. sellaeformis is not entirely

234

GEOLOGY OF THE COASTAL PLAIN

conclusive since this fossil has also been found in the Hatchetigbee formation of the Wilcox group in Alabama.'
The dark colored and drab, laminated sandy clays exposed in the bluff at Fort Gaines can be traced eastward and appear at a number of localities in Clay, Quitman, and Randolph counties. The clays become characteristically glauconitic in these counties,_ while apparently a considerable thickness of unconsolidated vari-colored, non-calcareous and kaoll.nic sands lie between the. clay and calcareous member of the lower Eocene.

Outhbert.-An excellent exposure occurs in the public road at Peterson Hill, four and one-half miles north>vest of Cuthbert.

Vertical section in strata at Peterson Hill.

Claiborne group ? 8. Incoherent red sand, very fine . . . . . . . . . .
Wilcox formation. 7. Orange-colored, fine-grained, clayey sand, residual
6. Gray, silty, laminated clay . . . . . . . . . . . ] 5. Gray, slate-colored and drab laminated clay, con-
tains thin glauconitic layers . . . . . . . . . 4. Clay in the nature of fullers earth, slightly glau-
conitic . . . . . . . . . . . . . . . . . . .. 3. G-lauconitic layer, a few fossils noted . . . . . . 2. Coarse red and yellow quartz sand, contains a lens
of white and yellow massive clay 8 feet thick . 1. Rather coarse, current-bedded sand, probably glau-
conitic near the top . . . . . . . . . . . . .

Feet. 15 15
55
4% 25 15

What is probably an unconformity between the glauconitic clay and the red sand of the overlying Claiborne group appears in a cut of trre Central of Georgia Railway near the 121 mile-post about three miles west of Cuthbert. The Wilcox strata here consist mainly of gray or drab laminated and jointed clay.
The beds lying above the marl and limestone on the upper Lumpkin road to eight miles north of Cuthbert, as exposed in the cuts and gullies along this road, are mainly drab or gray, sandy, laminated clay in the nature of fullers earth. At a few places red; incoherent sand was noted and a bed of white, very pure clay occurs between the five and six-mile posts. The thickness of the strata is inferred from natural exposures to be 125 to 150 feet. Red sand, either Claiborne or Vicksburg, appears on the highest hills.

Weston.-The following section appears in the Weston-Preston public road, one and one-half miles northeast of Weston, Webster County:

'Aldrich, T. H., Report on the Geology of the Coastal Plain, Ala. Geol. Survey. 1894, p. 236.

CLAIBORNE GROUP

235

Section one and one-ha!f miles northeast of Weston.

Age ?

Feet.

4. Red sand containing flint fragments; the flint

fragments contain characteristic Oligocene fos-

sils . . . . . . . . . . . . . . . . . . .

40 to 50

3. Coarse, red sand . . . . . . . . . . . . . .

10 to 15

Wilcox formation?

2. Drab, laminated clay, slightly glauconitic; some

poorly preserved fossils . . . . . . . . .

20

1. Black, sandy, glauconitic clay . . . . . . .

8

Beds 1 and 2 appear to be similar to the clays near Fort Gaines and

Cuthbert and probably represent the Wilcox formation.

Plains.-Gray, glauconitic sand appears at Magnolia Spring, two and one-half miles north of Plains, Sumter County, which is also probably a part of the Wilcox, although no fossils were observed.

Ellaville.-Fossils of the Wilcox formation were found south and southeast of Ellaville, Schley County. On the Lumpkin farm, on Goldendale Creek, six miles southeast of Ellaville, fossils were found in fragments of flint in a clay soil. The natural exposures are poor at this locality, and the field observations afford no evidence supplementing that of the fossils. Dr. Vaughan identified the following fossils from this locality:

Fossils from Lumpkin farm) Goldendale Creek.

Cassidulus ( ?) sp. Actaeon Turritella mortoni Conrad Calyptrea aperta (Bolander) Dentalium

Leda pharcida Dall Glycymeris Ostrea thirsae (Gale) Cardium Cardium

Andersonville.-The weathered exposures at Andersonville, Sumter county, reveal deep red sands and the fresher exposures in gullies reveal white and red cross-bedded incoherent sands. A thick bed of white clay is reported in a well 90 feet deep, near the station. In a cut of the Central of Georgia Railway, two miles north of Andersonville, 35 feet of white and red, incoherent quartz sand which presents a most wonderful display of eross-bedding, is exposed. Thin beds of limonite or ferruginous sandstone in the loose sands were noted in this vicinity. A sandy clay containing scattered glauconite grains resembling the glauconitic clays of the Wilcox formation was found near Hodge's Mill on Sweetwater Creek, one mile E>Outh of Ander-
sonville.
I

CLAIBORNE GROUP

The Claiborne group, or Claiborne formation, where the strata representing the group are not subdivided into constituent formations, derives its name from the old town of Claiborne, on Alabama River,

236'

GEOLOGY OF THE COASTAL PLAIN

once a prosperous village but now represented by only a warehouse

and boat-landing. The boat-landing is at the foot of the Claiborne

Bluff, one of the classic localities of American geology. It was from a study of fossils collected here that Conrad1 first recognized the pres-

ence of strata of Eocene age in the United States. The Claiborne

group is continuous from Alabama into Georgia, where it occupies the

same stratigraphic position, above the Wilcox and beneath the Jack-

son, and is characterized by the same species of fossils as in the former

State.

The Eocene age of the marl and limestone at Shell Bluff in Georgia,

along with the strata of Claiborne Bluff of Alabama, was first recog-

nized by Conrad.' In 1900, Dr. T. Wayland Vaughan' visited the

Shell Bluff locality and established the Claiborne age of the exposure

below the Ostrea georgiana bed. In 1908, Prof. S. W. McCallie gave

a brief description of the Claiborne and published an extensive list of

Claiborne fossils, chiefly identified by Dr. Vaughan, obtained mainly

from the region east of Ocmulgee River.

D. W. Langdon' first recognized the presence of Claiborne strata on

Chattahoochee River, while beds of Claiborne age were first discrim-

inated on the Flint by J. W. Spencer."



The Claiborne group in Alabama is subdivided into three forma-



'1



twns, v1z. :

Gosport greensand
Lisbon formation Tallahatta buhrstone

Although in a general way the correlatives of these formations may be recognized in Georgia, the extension of the use of these terms to this State is inappropriate, since the Claiborne group is not naturally -divisible into the same units as in Alabama; therefore, in Georgia the group is divided into two formations, with the recognition of a member in one of the formations, viz. :
Barnwell sand McBean formation, with. the Congaree clay member.

1Proc. Acad .Nat. Sci., Philadelphia, 1834, Vol. 7, pp. 116-157. 2Amer. Jour. Sci., 2d ser., Vol. 41, 1866, p, 96. Science, n. s., Vol. 13, Feb. 15, 1901, p. 270. Bull. Geol. Survey of Georgia, No. 15, 1908, pp, 33, 34, 336-348. Bull. GNL Soc. America, Vol. 2, 1891, pp. 597, 598. Rept. of Progress, Geol. Survey of Georgia, 1890-1891, p, 51. Smith, E. A., Underground water resources of Alabama: Geol. Survey of Alabama, ~907, pp. 17, 18.

:tchEAN FORMATION

237

Sloan1 has proposed a number of phase nam~s for the various aspects of the Claiborne group as it is exhibited in South Carolina and in two instances the usage of names for subdivisions of the Claiborne group is extended from there into Georgia.

McBEAN FORMATION

NAME
The name McBean is derived from the town of McBean in Richmond County, Ga., and from McBean Creek which forms the boundary between Richmond and Burke counties. The formation to which the name is here applied is well exposed near the town of McBean and southward along McBean Creek to its confluence with Savannah River. According to Dr. Vaughan the formation is equal to the Tallahatta buhrstone plus the Lisbon formation of Alabama, and the top of it may include the base of the Gosport greensand of the Alabama section.
DEFINITION
Stratigraphic relations.-The McBean formation rests unconformably u_T;>on strata of Lower Cretaceous age east of Ocmulgee River. This unconformity represents a long interval of time, for the two lower Eocene formations, the Wilcox and Midway, and all of the Upper Cretaceous deposits, aggregating a thickness of 3,000 feet or more, are absent in this region. Tongues of McBean strata also lap over the Cretaceous and even extend to the crystalline rocks of the Piedmont Plain. The most notable of these overlaps are at Roberts, Harlem, and Grovetown.
Between Flint and Chattahoochee rivers the McBean formation rests upon the Wilcox formation. Along Chattahoochee River, in the vicinity of Fort Gaines, there is evidence of an erosion unconformity, probably of minor importance, separating the two formations.
The formation in eastern Georgia is overlain by the Barnwell sand which in this region constitutes the upper formation of the Claiborne group. The relations between the two divisions are somewhat obscure. Along the northern margin of the areal occurrence of the Barnwell sand there is evidence of an unconformity of slight time importance separating it from the McBean formation, but farther southward the former seems to rest upon the latter with conformable relations. It seems probable that near the close of the time of deposition of the McBean formation there was an uplift which brought the northern margin of the area of Claiborne deposition above sea-level, permitting erosion to take place in the emerged area, while deposition continued in tile area which remained under water. The uplift was of

1Catalogue of mineral localities of ~outh Carolina: Geol. Survey of South Carolina, 1908.

238

GEOLOGY OF THE COASTAL PLAIN

short duration, however, the emerged tract being soon submerged again allo~wing deposition to continue as before over the whole belt.
The Barmvell sand may be, in fact probably is, present west of Flint River, but as there is some doubt as to its identification in this area there is lack of definiteness regarding the stratigraphic relations between the McBean and the overlying formations.
Lithologic characters.-The formation consists mainly of clays in the nature of fullers earth, shell marls, sandy limestones, and calcareous, glauconitic sands. The marls are for the most part massivebedded and friable, but hard, compact, and even partially silicified beds were noted on Savannah River. They may also be represented by alternate layers of marl or calcareous sand and laminated clay. The greatest thickness of the marl beds is in the Savannah River bluffs where, at Shell Bluff, there is an exposed thickness of over 100 feet.
The' marls of the :McBean formation reach their greatest development on Savannah River; they extend southward from Shell Bluff about 11 miles in a direct line to a point one and one-half miles below Griffins Landing, where they appear in the bluff 50 feet above the water level. westward from Savannah River, marls are exposed near McBean, Louisville, Tennille, Sandersville, and at other localities.
The Flint River exposures are friable, calcareous sands, sandy limestones, marls, and sa:o.dstones. On Chattahoochee River, Langdon recognized a lower "Buhrstone" member and an upper calcareous member. The formation here presents a variety of lithological phases as elsewher~gray, glauconitic limestones and marls resembling those on Savannah River; calcareous clays and claystones, and red and vari-colored unconsolidated sands.
Exposures of the formation are of small areal extent, and the marls and other materials have had but little effect upon the soils of the region underlain by them.
The marls are usually replete with fossils, the casts and shells of mollusca being the most common. Vertebrate remains, fish teeth, fragments of bones, etc., Bryozoa, and corals have been collected.
A portion of the McBean formation consists principally of fullers earth, and drab or greenish sandy clays. This is a depositional phase of the terrane. It is best exposed along the northern margin of the formation, extending approximately from Grovetown, Columbia County, to near Macon. This phase will be described on following pages as the Congaree clay member of the McBean formation.
The McBean formation as a whole presents a marine aspect, and was doubtless deposited near shore and in shallow water.

McBEAN FORMATION

239

Thickness.-The thickness of the McBean formation east of Ocmulgee River is estimated at 300 to 400 feet. The maximum expo;ed thickness occurs at Shell Bluff, Savannah River, where 115 feet of strata were measured. The thickness of the Claiborne group near Louisville, Jefferson County, estimated from the record of an oil-prospecting well, is 350 feet the greater part of which is referable to this formation, although the upper 68 feet may belong to the Barnwell , sand. The lithologic character of well drillings from Waynesboro indicate that the maximum thickness of the Claiborne group is not over 500 feet, perhaps less, at this place; all except about 100 feet of this is referabte to the }\fcBean formation. In parts of the area over which the McBean is the surface formation, the thickness will vary from not over 50 to 150 feet., The thickness along Ocmulgee and Oconee rivers is certainly much less than that along the Savannah, suggesting that there was probably a basin in the Savannah area during the Claiborne epoch.
Between Ocmulgee and Chattahoochee rivers where the Barnwell sand has not been certainly identified the thickn~ss of the Claiborne group seems to be in general less than in Burke County.
On Chattahoochee River, the estimated thickness of the Claiborne group is 250 to 300 feet. On the Flint, judging from the width of the outcrop, the thickness does not exceed that on the Chattahoochee and is probably less. The thickness between these two rivers, as shown by natural exposures, is not greater than 150 or 200 feet. Southward, under cover of the younger formations, the Claiborne group may diminish in thickness since the combined thickness of the Eocene is not more than 700 or 800 feet as shown by the record of an artesian well at Albany. (See page 317.)
Paleontologic characters.-The most extensive collection from any single locality in the area underlain by this formation was made by Mr. Earle Sloan, at Sloan's Scarp on McBean Creek, between Me Bean Station and Savannah River. J\1:r. Sloan submitted his fossils to Dr. Vaughan who contributes the following list and notes.

List of fossils from Sloan's Scarp, McBean Creek. Collected by Earle Sloan.

Endopachys maclurii (Lea) Ringicula biplicata (Lea) Conus sauridens Conrad Pleurotoma kelloggi Gabb Pleurotoma texacona Harris Pleurotoma terebriformis Meyer Pleurotoma childreni Lea Pleurotoma lesueuri Lea Pleurotoma nodocarinata Gabb

Turritella arenicola Conrad Turritella carinata Lea Mesalia claibornensis (Conrad)
Tuba antiquata Conrad Amalthea pygmaea (Lea) Calyptrea aperta (Sol.) Crepidula lirata Conrad Lunatia eminula (Conrad)
Natica aemilunata Lea

240

GEOLOGY OF THE COASTAL PLAIN

Pleurotoma afl'. rugosa Lea

Sigaretus declivis Conrad

' Amblyacrum Amblyacrum

stantoni Vaughan . huppertzi var. penrose11

Solarium elaboratum Conrad (young) Solariorbis depressa (Lea) var.

Harris ?

Dentalium annulatum Meyer

Mangelia infans Meyer

Nucula ovula Lea

Marginella columba Lea

Nucula magnifica Conrad

Marginella semen Lea

Leda media Lea

Caricella demissa var. texana Gabb Yoldia psammotaea Dall

Caricella aff. pyruloides (Conrad) Area rhomboidella Lea

Clavelithes humerosus Conrad

Ostrea sellaeformis Conrad

Fusus bellus Conrad

Pecten wahtubbeanus Dall

Fusus morton! Lea

Crassatellites protextus (Conrad)

Lirofusus thoracicus (Conrad)

Venericardla sp. (also at Lisbon, Ala.)

Typhis gracilis Conrad

Venericardia alticostata (Conrad)

Pyrula (Fusoficula) texana Harris Venericardia planicosta Lamarck

Lelornynus prorutus Conrad

Phacoides papyraceus (Lea)

Laevibuccinum prorsum Conrad

Bornia prima (Ald.)

Mitrella mississippiensis Meyer &

Cytherea discoldalis Conrad

Aldrich

Metis raveneli (Conrad)

Phos sagenum (Conrad)

Tellina mooreana Gabb

Buccinanops altile (Conrad)

Pteropsis lapidosa Conrad

Pseudoliva vetusta (Conrad)

Corbula alabamiensis Lea

Lacinia alveata Conrad

Corbula densata Conrad

Turritella nasuta Gabb

Corbula fossata var. extenuata Dall

Turritella nasuta var. houstonia

Harris

"Mr. Sloan also obtained a number of species that I was not able specific ally to identify; some of these are new, while others have probably been de scribed, but the groups to which they belong have not been thoroughly studied, This is a most interesting collection as it furnishes an excellent basis for correlation with other South Atlantic and Gulf Coastal Plain States. Deposits of the same age occur at Keitt's Ravine and Lang Syne in South Carolina, where Sloan calls them Warley Hill marl; at Pooser's Hill and Caw-caw Swamp, where they are called Cawcaw shale and marl by Sloan; at Decariduc place, near Aiken, and at Hixon bridge, Tinkers Creek, Aiken County. At the last named locality Sloan calls the horizon Barnwell phase, The horizon in Alabama and Mississippi is represented by the Lisbon formation; in Louisiana by the Upper portion of the St. Maurice formation; and in Texas by the Cook Mountain formation.
"In Georgia the McBean formation includes two paleontologic horizons. The lower one has been discussed in the preceding remarks. It is especially characterized by ;?leurotoma nodocarinata Gabb, Turritella nasuta Gabb,
Turritella nasuta var. houstonia Harris, Ostrea sellaetormis Conrad, Pteropsis lapidosa Conrad, and Corbula tossata Meyer and Aldrich,
"A higher horizon is represented especially well along Savannah River, between Shell Bluff, upstream, and Griffin's Landing, downstream. Along this stretch of the river a prominent ledge, largely composed of Ostrea georgiana Conrad, forms the top of the McBean formation. Although this formation could be subdivided along Savannah River it was found impractica;ble to extend the subdivision westward, for which reason the Ostna georgiana bed is considered as constituting its upper portion.
"Mr. E. W. Berry has studied the fossil plants of the Congaree clay mem
ber and his results are ready for publication as a Professional Paper of the U. S, Geological Survey."

Areal distribution.-Outcrops of the McBean formation occur in an extremely irregular belt, varying from a few miles to 25 miles or more in width, and extending entirely across the State. In the re

GEOLOGY OF THE COASTAL PLAIN OF GEORGIA.

PLATE XIX.

B. LAYER OF PISOLITIC CLAY BOWLDERS NEAR THE BASE OF THE CLAIBORNE GROUP IN A PIT OF THE AMERICAN CLAY COMPANY, ELEVEN MILE POST. TWIGGS COUNTY.

McBEAN FORMATION
gion between Savannah and Ocmulgee rivers this belt lies to the south of the belt in which the Lower Cretaceous strata come to the surface, and between Ocmulgee and Chattahoochee rivers it lies to the south of the area in which the Midway and Wilcox formations outcrop.
On account of the difficulty in distinguishing between the weathered phases of this formation and the overlying Barnwell sand, the Claiborne group has ben given one color bn the geological map, no attempt being made .to map the two formations separately. East of Flint River, exposures have been studied in the following counties: Columbia, Richmond, Burke, McDuffie, Jefferson,_ Glascock, \Vashington, Baldwin, Wilkinson, Jones, Twiggs, Bibb, and Houston. Exposures also occur on Flint and Chattahoochee rivers. It is evident that east of Ocmulgee River the formation originally entirely concealed the Lower Cretaceous and lapped over to the crystalline rocks of the Piedmont Plain, but it has been extensively modified by erosion and the northern limit of outcrop, as marked on the map, is a jagged line, since streams haYe cut through it and exposed the underlying Cretaceous.
Physiogrq,phic expression.-Over practically the wh;le of the area ot its occurrence east of Ocmulgee River the formation is overlain by the Barnwell sand, the beds appearing at the surface only in the stream bluffs and on the lower slopes and in the bottoms of the val~eys. On account of the compactness of the materials composing it, the formation has been effective in places in preventing the rapid reduction of the valley sides from steep to gentle slopes, but otherwise it has had only a subordinate part in determining the topographic aspect of the region that it underlies.
Structure.-The McBean formation shows a low dip southward. The dip of individual beds is so slight that they appear horizontal in natural exposures. The slope southward for the formation as a whole is perhaps not more than 10 or 1.5 feet per mile. No pronounced folding or faulting of beds has been observed. Langdon1 noted low flexures along Chattahoochee River; only purely local disturbances such as might be due to land slips or weathering and solution of calcareous strata, were noted in the Ocmulgee-Savannah area. The thick clay and fullers earth beds show minute jointing. Clay laminae show slight crumpling at a few localities but this is of doubtful regional significance. An exposure of the McBean occurs four and one-half miles south of Perry, Houston County, at an elevation higher than Jackson outcrops lying to the north. The structural relations are unexplained. It is probable there has been folding or faulting.
1J..angdon, D. W., Report on the Coastal Plain; Geol. Survey of Alnbama. 18-Hl. p. 38!l.


242

GEOLOGY OP 'l'HE COAS'l'AL PLAIN

LOCAL DETAILS

l\ICllEAX CREEK AREA, RICHM:OXD AND BURKE COUNTIES

111cBean and vicinity.-McBean, Richmond County, is situated on the Central of Georgia Railway, 22 miles south of Augusta. The exposures of the :McBean formation are principally on the south or

Burke County side of McBean Creek. The following notes are by Dr. T. Wayland Vaughan:

Section in gully on ~Jouth side of McBean Creek, one-quar.ter of a mile

south of :McBean Station.

BarnwEll sand.

Feet. In.

5. Silicified coquina rock imbedded in sand . . . .

4. Yellow and white sands, portions very fine,

others coarse . .

32

6

McBean formation.

3. Drab clay forming an indurated stratum, some

lignitic matter . . . . . . . . . . . . . . . 1 6

2. Greenish-yellow, rather fine-grained, argillaceous

sands, with black specks and lignitic pockets.

These sands becoming variably yellow and red 6

1. Light greenish-yellow, non-laminated clay, with a

little calcium carbonate . . . . . . . . . . . 2 6

Gully 300 or 400 feet east of the preceding, Southern end of gully.

Barnwell sand.

5. Red, sandy clay . . . . . . . . . . . . . . . . 2

:lvicBean formation.

4. Thin seam M lignite . . . . . . . . . . . . . . .

llh

3. Greenish clays, containing lignite .

5

6

2. Marl with calcareous concretions .

6

Feet In.

1. Greenish-yellow, calcareous clay . . .

1

Western side of gully.

Barnwell sand.

5. Red sands .

3

9

McBean formation.

4. Greenish clay similar to No. 2 . . . . .

0

7

3. Thin seam of lignite following irregular contour l

} of upper surface of No. 1 (corresponds to No.
4' of preceding section) and 2. Greenish clay . . . . . . . . . . . . .

2

1. Greenish-yellow calcareous marl . . . .

2

Eastern side of gully.
Barnwell sand. 3. Reddish sands . . . . .
McBean formation. 2. Greenish-yellow lignitic clay . . 1. Calcareous marl with 0. sellaeformis

Westerly exposure at McBean Creek. three-tenths of a mile

west of Bates Miller's store.

Barnwell sand.

2. Yellow, gray, and red sands . . . . . . . . . . 32

6

McBean formation.

1. Soft, chalky limestone, indurated in places, con-

taining 'l'urritella carinata, Nucula ovula,

Corbula gibbosa, Pteropsis lapidosa . . . . . 12

1WcBEAN FORi\IIATIOX

243

Along the road to Thos. B. Cox's house deep red, compact sands, and de-

composed glauconite with pebbles near 'base, are seen overlying the material

composing the preceding sections. Large masses of silicified coquina and

chalcedony (buhr-rock) with numerous poorly preserved fossils, Mortonia,

Turritella obruta, Oorbuld alabamiensis, etc., Claiborne fossils, occur from

eight f.eet of the base to the hill summit. The observed thickness along this

road was 52 feet.



Sechor~ on Thos. B. Cox's land, six rniles southeast of McBean

station, from his residence to creek, one-half mile to the northeast.

Barnwell sand.

4. Red sand with "buhr-rock" . . . . . . . . . . .

McBean formation.

3. Blue-green gray shale, nonfossiliferous . . . . .

2. Glauconitic, friable, or indurated limestone

(chalky) with Claiborne fossils .

'

1. Blue clay with rot1oen calcareous fossils ( Clai-

borne) Oorbula alabamiensis . . . . . . . . .

Feet. 105
20
4
1

SAYAXXAII RlYEH, DURKE COUNTY
Shell Bluff.-Sht~ll Bluff is a classic locality and stratigraphically one of the most important exposures in the Georgia Coastal Plain. The bluff is located in Burke County, on Savannah River, 40 miles by river below Augusta, and 15lh miles by the public wagon road, northeast of Waynesboro.
The bluff has been referred to in geologic literature more often than any other Georgia locality. Probably the first reference was made by William Bartram,' the English traveller, in 1791. Prof. John Einch' probably had this locality in mind in a paper published in 1824, though it is not mentioned specifically. V anuxem3 furnished the first geologic description of any consequence, for a paper read by S. G. }\lorton in.1828, and regarded the strata as upper Tertiary. The fauna of the bluff was studied by Conrad/ 1834, who was tho first to ciassify the beds as Eocene. He gave the name Ostrea georgiana to the common oyster, ;:tlthough this fossil was apparently known to Vanuxem' before this date ancl was named by him Ostrea gigantea. This locality was visited by Sir Charles Lyell in 1842, and is described in "Travels in North America," published in 1845. Lyell" collected 40 specimens and determined the rock to be Eocene.
The stratigraphic.position of the beds was a subject of discussion in 1866, when Conrad' proposed the name "Shell Bluff Group" for strata characterized by Ostrea georgiana:, and which he placed below the "Orbitolite limestone of the Jackson group." Hilgard,' ho\vever,

1Travele through North Carolina. Sonth Carolina. Georgia and WeRt Florida, etc..
Philadelphia. 17Pl. 2Amer. Jour. Sci., Vol. 7. 1824, pp. 31-43. 3Jonr. Acad. Nat. Sci., Philadelphia, Vol. 6, pp. 59-71. 'Idem. Vol. 7, 1834, pp. 156-157. 5Ibid, Vol. 6. 1830. Travels in North America, Vol. 1, p. 158. John Murray. 1815. 7Amer. .Jour. Sci. 2d ser., Vol. 41. 1866, p. 96. 8Ibid. Vol. 42, 1866. pp. 68-70.

244

G~OLOGY OF THE COASTAL PLAIN

placed the "Shell Bluff group" above the Jackson, and disputed the occurrence of Orbitoides below the Vicksburg. Dr. W. H. Dall,' in 1895, placed the "Shell Bluff group" under the lower Oligocene or Vicksburgian, but stated that its position was not definitely settled. Dr. Vaughan' made paleontologic studies later and concluded that the marl below the Ostrea georgiana bed belonged in the lo-wer portion of the Claiborne group o:f the Eocene.
Recent studies of the strata by the writers in the vicinity of Shell Bluff post-office, Burke County, and Hancock Landing, Savannah River, have establi::.hed the fact that the OstJea georgiana bed, 75 to 110 feet above Savannah River, and the overlying red sands should also be referred to the Claiborne group.
Sections and O:escriptions of the bluff have been published by Ruffin,' Loughridge,' W. B. Clark, and Earle Sloan." Sections made by different observers vary greatly in detail,-the variations are perhaps due in the main to the imperfection of the exposures and to the fact that the sections were made at different points along the bluff; also, to differences in the usage of descriptive terms, completeness or incompleteness of the sections, and to the object in view, whether stratigraphic or economic.
The length of the bluff against which the river impinges is about 1,000 feet and it attains a maximum height of 150 feet. According
to the reports of the 11. S. Army Engineers the river level here is 87.1
feet above sea-level. Dr. Vaughan has made careful stratigraphic studies here and has
supplied the following section and notes:

Section of Shell Bl11f{, mouth of Boggy Gut Creek, on Savannah River.

Feet.

15. Soil and humus . . .

McBean formation.

14. Indurated fossiliferous limestone . . . . . . . 1

13. Softer limestone with some sand, (in the upper-

most part of this a specimen of Pteropsis

lapidosa was collected) . . . . . . . . . . . . 6.5

12. Ledge of hard limestone . . .

3.4

11. Softer sandy stratum . . . . . . . . . . . . . 3.7

10. Harder stratum . . . . . . . . . . . . . . . . 1

9. Softer stratum . . . . . . . . . . . . . . . . . 1.1

8. Whitish limestone, blotched yellow or brown,

with Claiborne fossils . . . . . . . . . . . . 4.25

1U. S. Geol. Surv., 18th Ann. Rept., pt. II, p. 342. 2Sci., D. s., Vol. 13, p. 270, 1901. 'Report of Commencement and Progress of the Agricultural Survey of South Carolina. 'Tenth Census, Vol. 6, pt. 2, p. 280 (bottom pagination). 5Bull. U. S. Geol. Survey No. 83. p. 55. catalogue of minPrnl localities: Geol. SnrvPy of South Carolina, p. 271.

McBEAN FORMATION

245

Feet. 7. Yellow sand, more calcareous at top, containing

Ostrea sellaeformis

13

6. Softer ledge .

7

5. Harder limestone ledge .

4.5

4. Softer ledge

.5

3. Harder ledge

2.3

2. Soft limestone, whitish or yellowish, loosely

granular .

5.5

1. Talus above water's edge .

7

"The whole section at Shell Bluff Landing is not well exposed because of talus coverings of portions of it. The base of the Ostrea georgiana bed is about 80 feet above zero water level in the river, or between 70 and 75 feet above the river bank at the landing. There is 8 to 12 feet of the section unexposed. The total thickness of the Ostrea georgiana bed is approximately 24 feet, above which are yellowish sands and soil.

Detailed section of a portion of the Ostrea georgiana bed is as follows:

McBean formation. 9. The upper 9lh feet of thickness of this bed is largely talus-covered, but fragments of oysters were found on the surface, and it was inferred that the thickness is approximately as repres.ented . . . . . . . . . . . . . . . . . . . . 3. Calcareous conglomerate containing small quartz pebbles and poor fossils, one of them a coral, apparently Oladocora . . 2. Talus of yellowish sands . 1. Oyster ledge . . . . . . .

Feet.
9.5
3.5 6 5

Top of stratum No. 13, Shell Bluff, Ga.,, near mouth of Boggy Gut Oreek: Pteropsis lapidosa Conrad
stratum 11, near mouth of Boggy Gut Oreek:

Ostrea sellaeformis Conrad

Stratum No. 8 or 9 near mouth of Boggy G-ut Oreek:

Carophyllia subdichotoma Lons. Dendrophyllia sp. Endopachy maclurii (Lea) Plejona petrosa (Conrad)
Fusus trabeatus Conrad Fusus limulus Conrad ? Fusus irrasus Conrad ? Calyptraea aperta (So}ander) Crepidula lirata Conrad Dentalium thalloides Conrad Nucula magnifica Conrad Leda pharcida Dall ? Glycymeris trigonella (Conrad)

Glycymeris sp. indet. ( ?) staminea (Conrad)
Crassatellites protextus (Conrad)
var. Venericardia planicosta Lamarck Venericardia alticostata (Conrad) Cytherea texacola Harris Cytherea perovata Conrad ? Cytherea discoidalis Conrad Cytherea poulsoni Conrad ? Corbula alabamiensis Lea Cobula oniscus Conrad Corbula fossata Meyer and Aldrich

246

GEOLOGY OP THE COASTAL PLAIN

Stratum No. 8, near mouth of Boggy Gut Greek:

Endopachys maclurii (Lea)

Ostrea sellaeformis Conrad

Turritella (Mesalia) vetusta Conrad Cytherea sp.

Turritella humerosa Conrad ?

Pteropsis lapidosa Conrad

small variety

Lunulites bouei Lea

Nucula magnifica Conrad ?

Oxyrhina desori Agassiz

Stratum No. 3, near mouth of Boggy Gttt Creek:

Marginella constrictoides Meyer Nucula magnifica Conrad

and Aldrich

Pecten sp.

Turritena (Mesalia) vetusia Conrad ? Corbula fossata ;\feyer and Aldrich

Shell Bluff Landing, from horizon below the Ostrea georgiana bed anfl the same as stratttm No. 8 of the Boggy Gut Greek section.

Coral----Astrangia? Mesalia claibornensis (Conrad) Turritella humerosa Conrad
small v-ariety Calyptraea aperta (Sol.).

Leda sp. indet. Ostrea alabamiensis Lea. Venericardia planicosta Lam. Nucula (internal cast, probably mag-
nifica Con.).

Besides these: Lima? fragment, and a large gastropod, apparently a Naticoid.

"The strata in the bluff at Shell Bluff from the base upward including bed No. 13 correspond in stratigraphic position to the Lisbon formation and probably a portion of the Tallahatta buhr-stone of Alabama."

The following section was made by the anthors at a point abom 200 yards above the boat landing:

Section at Shell Bluff.
Barnwell sand. 10. Slope, true character oJ: the rock largely concealed; upper part red sand with thin covering of gray sand . . . . . . . . . . . . . . . . .
McBean formation. 9. Poorly exposed; fragments of Ostrea georgiana: strata probably calcareous sand and argillaceous limestone . . . . . . . . . . . . . . . 8. Hard, white limestone, full of shells . . . . . . . 7. White calcareous clay and sand with thin layers of pure limestone . . . . . . . . . . 6. Light, yellow or brown, fine sand, only slightly calcareous, partly consolidated . . . . . . . . 5. Soft, calcareous sandstone . . . . . . . . . . . . 4. Hard, calcareous sandstone full of comminuted shells . . . . . 3. Soft, friable, sandy marl . . . . . . . . . . 2. Hard, sandy limestone . 1. Yellowish, friable, sandy marl, glauconitic .

Feet.
70
20 1 15 8 8 3
4 1
12

Total ........ .

142

The following section occurs just below the boat landing and "' partly exposed in the wagon road leading to the top of the bluff:

McBEAN FORMATIOY

247

Section below the landing at Shell Bluff.

Eocene Barnwell sand. 4. Yellow and gray incoherent sand . . . . . . . . 3. Partly concealed, but largely coarse, red sand . .
McBean formation. 2. Sandy and argillaceous marl, varying in hard-
ness; contains some quartz pebbles as much as one inch in diameter. Large oyster shells were
found at 110 feet above the river, and a conspicuous bed of Ostrea georgiana occurs 75 feet above the river. The shells are also found
in soil at lower elevations but these may have rolled down from the higher beds . . Recent and Pleistocene. 1. Talus and alluvium to river level . . . . . .

Feet. 5 20
90 20

The calcareons rock at Shel1 Bluff, takPn as a whole, is a :-an<l.' ann argillaceOUS mad. It presents Yariations from romparatiYel:v pnre limestone through highly argillaceons ann f'andy marls to brown friable sano, only slightly calcareoUR. Silica and clay predominate over lime nnd the rork often prrsrntf' the asrx'rt of a filw sand in a matrix of clav ann calrinm carbonate. The sanrl \Yhirh is in mirrn scopic particles consists mainly of angnlar (]Hartz; scattrrecl, reddish brown neeoles, whirh are probablY rntile, were also noted, and a very small amount of \Yhitr mira was ohservro. The ralcinm rarbonate is finely disseminated and is also in the fonn of shells and fine fragments of shellR. Glanronite orrnrR bnt is not ahnndant. Smal1 brown or blark particles of fossilized bones appear in the rock in the lo\Yer part of the blnff and larger fragments are occasionally found. Some of the marls eont<lin scattered quartz pebbles from the size of a pea to an inch in oiamrter. The materials present a variety of colors such as white, g-ray. yellow, huff, and ye1lowish-g-reen. althong-h the aspect, as a whole, is white or g-r.ay. Shells of the large oyster, Ostrea georgianna. from which the bluff received its name, are con spicuous from 80 to 100 feet above the river level. The shells are nsnally long and narrow, having a lenp:th of 12 to 1 I) inches and a width of three or four inches; the valves are thick, often two inches. Very large specimens may have a length of 22 inches. Many sperimens of the yonng are curved or sub-oval in shape. As pointed out by Dall,' this species is characterized by "low, flattish, distally forked radial rihlets, quite different from anything obsened on the surface o 0. mauriciensis or 0. virginica,"
Rock of the same general lithologic character as that at Shell Bluff extends southward in the Savannah bluffs to a point one and one-half miles below Griffin's Landing, 17 miles by river from Shell Bluff..

1Trans. Wagner Free Ins. of Sci., 1903. p. 1555.

248

GEOLOGY OF THE COASTAL PLAIN

This is the last point at which it appears in the river bluffs, although probably it is near the surface still farther southward and lightly concealed by the overlying sand.

Demerie's Ferry.-Very fossiliferous limestone and calcareous sand similar to that at Shell Bluff appear a short distance above Demerie's Ferry, one and one-half miles below Shell Bluff. The calcareous bed at this point has an exposed thickness of 20 feet but it probably makes up the bluff to a height of 40 feet above the river. The marl and limestone bed is overlain by 50 to 60 feet of bright red argillaceous sand (Barnwell sand). The fact that the top of the marl is here only 40 feet above the river whereas at Shell Bluff it is over 100 feet above the same datum, means either that the red sands overlie the marls unconformably, or that the beds change from marl to calcareous sand or even to pure sand, in a short distance horizontally or that the true character of the strata above the limestone is concealed by \Yeathering and creep. The last explanation seems most plausible.
A portion of the bed is a silicified mass of fossils. V enericardia planicosta and a small coral, Endopachys maclurii, are abundant.

Hancock Landing.-Hancock Landing is about 11 miles by river below Shell Bluff. The bluff at the highest point is about 120 feet; (aneroid reading) above r~ver level. The rock exposed consi3ts 0f limestone, friable marl, brown calcareous sand, greenish or bluish calcareous clay, and local beds of quartzite. Beds of ash-colored marls occur at the base of the bluff; the marl contains glauconite and a variable percentage of quartz sand. The upper part of the bluff is a bro>vn and red sand, poorly exposed. Ostrea georgiana was noted here at a point 80 feet above the river, and it also appears at lower levels. The specimens show the ch.aracteristic ribbed markings. The beds in the lower part of the bluff, contain in addition to ::t lmge number of mollusca, fragments of bones, fish teeth and dental plates.
The Hancock Landing bluff recedes from the river for a short distance and is again washed by the river at Utley Point, one-half :mile below. Here, there is about 20 feet of ash-colored marl at tlh~ hase of the bluff, similar to that at Hancock Landing. The Btrata at ihe upper end of the bluff are partly concealed by humus and talus. On account of the occurrence of Ostrea georgiana a de.scription of this exposure 1s g1ven.

Section at Hancock Landing.

Barnwell sand.

Feet.

8. Red, argillaceous sand, poorly exposed; contains

no hard rock, and seems to be devoid of

fossils . . . . . . . . . . . . . . . . . . . . 40



McBEAN FORMATION

249

Feet. McBean formation.
7. Sandy, aluminous marl; contains large shells of Ostrea georgiana; other fossils are Endopachys maclurii, Oalyptrea aperta, Turritella carinata, Venericardia, Modiolus. This stratum is 80 feet above the river. Thickness exposed . . 5
6. Concealed by humus and talus; soil contains large oyster shells . . . . . . . . . . . . . . 35
5. Sandy limestone, containing Ostrea georgiana. This may have rolled down from a higher level, but the rock is unlike bed No. 7 . . . . . . . 4
4. Strata concealed . . . . . . . . . . . . . . . . 15 3. Laminated clay . . . . . . . . . . . . . . . . 4 2. Poorly exposed, but probably in the main, bluish,
sandy marl, and rather hard, bedded clay . . 15 1. Concealed to the river level . . . . . . . . . . 7
Blue Bluff.-This bluff is two miles below Hancock Landing. The
lower part is a gray or ash-colored glauconitic marl which assumes
a bluish color due to moisture. The secti::m about on,-third mile
above the bluff proper is:

Section about one-third mile above Blue Bluff.

Barnwell sand.

Feet.

5. Brownish, incoherent sand, forms a thin veneer)

over the plateau . . . . . . . . . . . . . .

4. Strata almost entirely concealed, small ex- 60

posure of red argillaceous sand . . . . . . .

3. Red sand, exposed on roots of blown-over trees .

2. Laminated, drab and greenish, sandy clay, partly

concealed . . . . . . . . . . . . . . . . . . 10

McBean formation.

'

1. Bluish and ash-colored, glauconitic marl; variable

in percentage of clay and sand. At the base

contains lines of white and blue limestone

nodules. The marl is fossiliferous and con-

tains the characteristic McBean species

Ostrea sellaetormis and Pteropsis lapiaosa . . 40

According to Dr. Vaughan, the basal bed of this section representE a horizon below the Gosport greensand of Alabama, probably within the Lisbon.

The part of Blue Bluff washed by the river shows the following~

Section of part of bluff washed by the river.

McBean formation. 2. At top, grayish and brown argillaceous marl :..nd thin bedded layer of jointed, aluminous sandstone. The upper part of the bluff lighter in color and more argillaceous than the lower part . . . . . . . . . . . . . . . . . . . . .

Feet. 25

250

GEOLOGY OP THE COASTAL PLAIN

Feet. 1. Bluish, glauconitic marl, massive bedded, con-
tains white fragile shells and casts; fossils,
Tttrritella nasuta, Letla pharcida, Lucina
subvexa, Pteropsis lapidosa . . . . . . . . . 12 "Stratum 1 represents a horizon in the lower portion of the Claiborne."
T. W. V.

The lower end of Blue Blu:ff shows a bluish marl which is similar to that in the sections described, and which contains limestone nodules. The marl is overlain by 50 feet of red, yellow and gray unconsolidated sands. These sands contain clay laminae, rarely small pebbles, and near the base imperfectly preserv-ed fossils.

Griffin Landing.-This locality is three miles below Blue Blu:ff, and 147 miles above Savannah. The large fossil oyster, Ostrea georgiana, is conspicuous in certain layers.

Section at Griffin Landing.
f Barnwell sand. 6. Gray, structureless sand covering the upland, probably residual . . . . . . . . . . . . .. 3. Red, rather coarse, quartz sand, free from pebbles; glauconitic? . . . . . . . . . . . . 4. Brown or yellow argillaceous sand, glauconitic . J McBean formation.
3. Large specimens of Ostrea georgianct embedded in greenish-gray argillaceous sand and drab-
clay . . . . . . . . . . . , . . . . . . . . . 2. Drab, laminated clay in the nature of a fullers
earth; not a persistent bed . . . . . . . . . . 1. Bed of large Ostrea georgiana in a matrix of pale
greenish-clay; one specimenfound which meas-
ured 20 inches in length; in addition to Ostrea georgiana, contains Calyptrea aperta, Motliolus,
Balanus . . . . . . . . . . . . . . . . . . .

Feet. 100
10 5
10

Lirne-lciln Bluff.-Exposures of stratigraphic interest occur in the blu:ff one and one-half miles below Griffin's Landing. Next to Shell Blu:ff, this is the highest blu:ff along the river; the level of the upland to the west was estimated to be 140 feet above t4e river. This is the site of an old lime-kiln, and since no local name for the blu:ff is known, the name "Lime-kiln" bln:ff is an appropriate designation.

Section at Lime-kiln Bluff.

l Barnwell sand. 5. Surface

covered

with

gray

sand .

.

.

.

.

. l

4. Largely concealed, but probrbly yellow or red

3. Br~~nd a~d ~ed ~a~d . : : : : : : : : : : : : J

Feet. 80

McBEAN FORMATIOY

251

McBean formation. 2. Thinly laminated clay, with micaceous sand partings, grades downward into layers No. 1 . 1. Sandy and clayey marl, both friable and consolidated; glauconitic; contains oyster shells, casts of other fossils, fish teeth and small fragments of bones . . . . . . . . . . . .
Another part of the bl.uff shows: Barnwell sand.
7. Slope, largely concealed, but probably sand and clay ........ , ....... (about) .
McBean formation. 6. Laminated clay with sand partings and thin layers of aluminous sandstone . . . . . . . . 5. Marl, containing Flabellum cuneiforme, Dendrophyllia, Oalyptrea aperta, Ostrea . . . . . . . 4. Sandy, laminated clay . . . . . . . . . . . . . 3. Bed composed of large oyster shells, Ostrea geargeorgiana in a matrix of sandy marl . . . . 2. White, massive bed of sandy marl; a few oyster shells in the upper part . . 1. Concealed to river 1evel . . . . . . . . . . . .

Feet. 10
50
50
20 2 to 3
3 20 20
5 or 6

The marl formation from Shell Bluff southward is regarded as representing a single formation of the Claiborne group, for no basis for a division was discovered. The red sands in the upper part of the bluffs are also regarded as part of the Claiborne group; there seems to be a transition from the marl to the red sands.

RICHMOND COUNTY
H ephzibah.-Marl of the :McBean formation occurs on the farm of W. G. Tarver on McBean Creek, six miles south of Hephzibah, where Pteropsis lapidosa was collected. The exposure is on the edge of the swamp at McBean Creek where one foot of the marl bed appears. The overlying red sand of the Barnwell division has a thickness of 50 or 60 feet. The marl bed lies at a lower level than the base of the Claiborne group at Hephzibah and probably is underlain at a slight depth by Cretaceous strata. Across this territory there is a marl bed (McBean formation) bearing a lower Claiborne fauna overlain by red sand which seems to correspond to similar lithologic material (the Barnwell sand) in the vicinity of McBean, where it contains an upper Claiborne fauna.

.JEFFERSO:"f COUXTY
Louisville.-The character of the strata of the Claiborne group in this region may be ascutained from, the record of an old oil prospe0ting well, three and one-half miles southwest of Louisville. From an examination of the borings it is belieYe<l that the base of the Clai-

252

GEOLOGY OF THE COASTAL PLAIN

borne is reached .at about 350 feet. The record of the upper part of the well is taken from the report on the Underground Waters of Georgia by S. W. :McCallie.'

Part1:az log of oil prospecting well near Louisville.

Mixed clay and sand . . . . . . . . . . . . . . from 0 to 68

Sand and rock . . . . . . . . . . . . . . . . . . . . . " 68 " 74

Blue clay . . . . ..

74 " 76

Blue clay and sand .

76 " 91

Blue clay . . . .

91 " 93

Sand . . . . . .

93 " 96

Hard rock ... .

96 " 96

Soft sand rock .

96 " 99

Sand ....

99 " 113

Hard rock ..

113 " 114

Sand ....

114 " 116

Soft rock ..

116 " 119

Hard rock .. .

119 " 120

Blue clay .. .

120 " 132

Sand rock .. .

132 " 142

Sand and clay .

142 " 150

Blue clay .. .

150 " 169

Sand . . . . . . . .

" 1.69 " 171

Blue clay and shale .

171 " 176

Hard rock ...... .

176 " 177

Blue clay and sand layers .

177 " 184

Hard rock ..... .

184 " 188

Sand . . . . . . . .

188 " 204

Hard rock .... .

204 " 205

Blue and white clay .

205 " 208

Hard rock . . . .

208 " 209

Sand . . . . . . .

209 " 213

Shale ...... .

213 " 219

Sand . . . . . . .

219. " 223

Blue clay and shale

223 " 269

Fine sand .....

269 " 275

Clay and shale . . .

275 " 298

Fine sand ..... .

298 " 307

Sand . . . . . . . .

307 " 505

It will be observed that no thick beds of either limestone or marl were encountered. The rock is principally sand, with a lesser amount of clay, containing shells. None of the borings indicated anything approaching pure limestone. The "hard rock," is probably sandstone or quartzite. With the exception of perhaps the first GS feet, all of the strata in the section down to about 350 feet belongs to the McBean formation.
A bed of oyster shells and marl found at Warren's Mill, three
mill miles east of Louisville io reported to have been excavated to a depth
of seven feet, the rock being used in the concrete work of a dam. There are no natural exposures. This rock is overlain by a bed of
1Geol. Surv. of Ga., Bull. 15, 1908, p. 129.

1~cBEAN FORMATION

253

fullers earth-like clay, which in places is rich in animal remainsshells, teeth, bones, etc. The surface formation is red sand.

W ASHINGTOX COUNTY
Sandersville.-A soft, white argillaceous limestone appears at the limesink on the_ B. T. Rawlings property, three-fourths mile south of the court house. The maximum thickness exposed is 10 feet. Fragments of an oyster, Ostrea georgiana} and Mortonia are abundant; the latter is so common as to attract local attention and is stylt>d "lime biscuit." The marl is overlain by red sand containing white sandstone beds.
Sandstone containing Ostrea georgiana and thin layers of quartzite occur at "The Spring" 0n the east side of the road, a short distance east of the limesink.
Prof. S. W. :McCallie has furnished the following description of a section at Rocky Branch bridge two miles northwest of Sandersville, (unpublished notes:)

Section a:t Rocky Branch Bridge.

Barnwell sand. 4. Reddish clays . . . . . . . . . 3. Sandstone . . . . . . . . . .
McBean formation. 2. Greenish sandy, glauconitic clay weathering yellow. This clay in places becomes silicified into flint-like layers, the total thickness being about . . . . .......... ...... . 1. Greenish glauconitic sand with shark's teeth and fragments of bone. About 100 yards further down the creek and apparently underlying the greenish glauconitic sands is a greenish, finely laminated clay with fragments of shells and plants .................... .

Feet. 10
8
8

The exposure in the vicinity of the spring, one mile south of Sandersville Court House, consists of sandstone mostly as loose boulders in the soil. The only fossils noticed here were oysters which are always more or less fragmentary.
A section at Limestone Creek, two miles south of Sandersville, made out from several exposures along the stream seems to be as folows:

Section at Limestone Creek.

McBean formation. 3. Sandstone with oyster shells (near top) . . 2. Sands and possibly some clay (only partially exposed) . . . . . . . . . . . . . . . . . . 1. Rotten fossiliferous limestone . . . . . . . . . .

Feet. 10
10 20

'fhe exposure along the creek is not continuous and the section here given is only approximately correct.

254

GEOLOGY OP THE COASTAL PLAIX

Tennille.-A soft, argillaceous marl occurs in a gully along the Central of Georgia Railway near the 139 milepost.

Section at 139-Mile Post.
Barnwell sand. 5. Bright, red sand, fresh exposures not seen . 4. Fragmentary, siliceous layer; contains fragments of an oyster and Scutella . . . . 3. Coarse,brown and yellow sand . . . 2. Interval concealed, probably sand .
McBean formation. 1. Soft, calcareous rock, glauconitic and probably contains a higher percentage of clay than lime; casts of fossils abundant . . . . . . . . . . .

Feet. 10
12
10 4
12

Prof. McCallie has compiled the following section from expowres betiYeen the 138 and 139 mile-posts (unpublished notes) :

, Section between ~Mile-posts 138 and 139.

Barnwell sand.

Feet.

9. Surface sands . . . . . . . . . . . . . . . . . . 0-3

8. Massive, orange-colored, sandy clays unconform-

able with beds below . . . . . . . . . . . . . 10

7. Stratified sands and clays with fragments of

oyster shells . . . . . . . . . . . . .

12

6. Sandstone often fossiliferous along the parting

planes . . . . . . . . . .

. . . . . .

4

McBean formation.

5. Greenish-gray clayey sand with fragments of

oyster shells . . .. . . . . . . . . . . . . . . 3

4. Whitish, putty-like clay with layers of flint con-

taining fossils . . . . . . . . . . . . . . . .

3. Sandy, glauconitic clay . . . . . . . . . . . . 3

2. Fossiliferous, soft limestone with hard ledges . 10

1. Bluish, tough clay with sand partings .

The following fossils were obtained by Prof. McCallie at this localit:v:

Fossils from near Tennille.

Glycymeris trigonella (Conrad)

Corbula alabamiens!s Lea .

Glycymeris idonea (Conrad)

Crassatellites altus (Conrad)

Mortonia sp., the common Eocene Crassatellites protextus var. lepidus

species of eastern Georgia

Dall

Endopachys maclurii (Lea)

Ostrea alabamiensis Lea

According to Dr. Yanghan the geologic horizon is Claibornian and

seems to be in the uppermost portion, i. e., above the Ostrea sellae-

formis-Pteropsis lap1:dosa zone, or the fossils come from the Barnwell

sand.

Snnhill.-A bed of compact, crystalline limestone outcrops one-

quarter of a mile south of the depot, and was at one time used in the

mannfactnre of lime.

J![cBEAN FOKWATI0-:\7

255

Section at old lime-lciln, 8unhi1l.

Barnwell sand.

3. Dark, red, fine-grained, sand, surface aspect due

to weathering, contains vitreous fiint, prob-

ably due to replacement of a calcareous

rock . . . . . . . . . . . . . . . . . .

2. Argillaceous sand . . . . . . . . . . . . . . .

McBean formation ?

.

1. White, compact limestone, containing shells and

Bryozoa; Flabellum cuneiforme Lonsdale,

Venericardia alticostata, etc. . . . . . . . .

Feet.
15 1.5
6+

Davisboro.-Large boulders of flint, which are residual and eYidently a replacement of limestone, occur two miles southeast of Davisboro, on the property of S. J. Taylor, on a small tributary of Williamson's Swamp Creek. The rock contains poorly preserved fossils and has the appearance of the flint of the Claiborne group.
The following section occurs at Tarver's :M:ill, eight miles southeast of Davisboro:

Pliocene ?

Section at Tarvers' Mill.

Altamaha (Lafayette?) formation 6. Mottled argillaceous sand covered with gray

sand . . . . . . . . . . . . . . . Eocene.
Barnwell sand ( ?)

o. Red sand . . . . . . . . . . . 4. Red and yellow sand . . . . . . 3. Clay layer . . . . . . . . . . . 2. Yellow and white quartz sand. McBean formation. 1. White, sandy claystone; contains fragments of
shells and sharks teeth, exposed to water's edge . . . . . . . . . . . . . . . . . . . . .

Feet. In.
10+
20 12
0 6 15
5

There are no data to establish the stratigraphic position of the beds here definitely; the succession, red and yellow sands over clay, suggests identity with sections of the Claiborne group elsewhere.

TWIGGS COUXTY
The northern part of Twiggs County presents much the same succession of beds as Wilkinson County, (see page 293. )-namely, red and vari-colored sands over drab, massive and laminated clays and fullers earth, both of which rest uncomformably upon white clay beds and kaolinitic sands of the Cretaceous. There are also beds of sandstone, quartzite, and limestone in the Claiborne group.

Dry Branch.-Fine exposures appear at the ''arions clay mmes near Dry Branch.

256

GEOLOGY OF THE COASTAL PLAIN

Section at the rnines of the Georgia Kaolin Company, two

southeast of Dry Bra1nch.

Barnwell sand.

Feet.

5. Fine, red sand observed along the slope to the top of the ridge-dark, red color, probably

a surface phenomenon due to weathering . . 100 McBean formation?
4. Greenish and drab, faintly laminated clay of low specific gravity, contains casts of fossils; contains local lenses of soft, friable limestone, a foot or two in thickness . . . . . . . . . . 15
3. Fine, yellow, quartz sand . . . . . . . . . . . . 12

2. Soft, white limestone, and limestone and kaolin breccia; contains characteristic Claibornian fossils, corals, a large oyster, Nucula ovula

Lea, Leda sp., Grassatellites altus (Conrad),

Venericardia planicosta Lamarck, Cytherea

perovata Conrad, etc. . . . . . .

4

(Unconformity)

Lower Cretaceous.

1. Massive beds of white clay . . . . .

20

miles

Stratum No. 2 presents a curious breccia, consisting of soft fossiliferous limestone and chunks of white clay. The white clay was evidently derived from the underlying bed but the limestone is in its place of origin.

Another local development of limestone appears in a ravine a short distance southeast of the mines. This lies 10 to 15 feet above the Cretaceous, but from. the fossils it is known to belong to the Jackson formation, (see page 304.)

Gallemore.-A fossiliferous marl or limestone occurs in the bed of the creek at the mill near Gallemore or Willis Station. The rock it> a bluish-gray, siliceous marl which in places is indurated. It consists of fine quartz sand, imbedded in a matrix of clay and calcium carbonate,_ and has much more the lithological aspect of the McBean formation than of the Jackson or the Vicksburg, which appear a short distance farther south.. Fossils are abundant, and an oyster wlls noted, the species of which has not been determined.
Prof. McCallie collected the following fossils at Gallemore Station, Twiggs County:

Fossils frorn Gallemore Station..
Plejona pretosa (Conrad) Calyptrea aperta (Solander) Turritella carinata Lea Mesalia vetusta (Conrad) Leda sp. Glycymeris sp. Diplodonta ungulina (Conrad) ? Phacoides alveatus (Conrad) Corbula sp.

McBEAN FORMATION

257

The following succession of beds was noted at Rocky Hill, onp mile southwest of Gallemore:

Section at Roclcy Hill.

Barnwell sand.

Feet.

3. Red sand similar to the Barnwell sand at other

localities . . . . . . . . . . . . . . .

40

2. Siliceous limestone or flint . . . . . . . .

8

McBean formation.

1. Drab, clay, laminated, porous, and like fullers

earth . . . . . . . . . . . . . . . . .

( ?)

South of this locality the Altamaha (Lafayette ? ) and Vicksburg formations appear at the surface.
In the western part of the county there are numerous exposures, showing the McBean formation in contact with the Cretaceous. At a point one mile south of Bond's store, or Delzel postoffice, the Congaree clay member reaches a thickness of 80 feet and is overlain by red sand. The red sand of this formation, which is frequently coarse and contains limonite crusts and hollow nodules, is in pl1lccs in contact with the Cretaceous, the heavy fullers earth-day beds being absent. Local beds of limestone are reported.

AREA WEST OF OCMULGEE RIVER
The strata between Flint and Chattahoochee rivers present a close general lithologic similiarity to those of the eastern area. Along the northern margin of the formation, red, rather coarse sands at the surface overlie laminated or thin bedded clay, while southward or seaward the beds are calcareous, and sandy marls, very similar to those along Savannah River, interbedded with clay, are overlain by red sand similar to the Barnwell sand. Flint appears to be absent, but there are occasional thin sandstone or quartzite layers in thA sand. Clay or fullers earth is less extensively developed, but H1is phase is represented by drab, laminated, fossiliferous clays, such as occur at the base of the formation at Fort Gaines.
Within the area lying between Ocmulgee and Chattahoocher rivers exposures of strata belonging to the Claiborne group have bren examined four and one-hal miles south of Perry, Houston County; along Flint River at several localities, notably at the old Danville Ferry and at Penny Bluff; and along Chattahoochee River for a considerable distance below Fort Gaines. Other localities in the Chattahoochee drainage area are described on subsequent pages of this paper. Fair collections of fossils have been obtained from a number of exposures rendering it safe to state that the ]\fcBean formation extends uninterrupted]~- from Savannah to Chattahoochee rivers. However,

258

GEOLOGY OF THE COASTAL PLAIN

the formation is often masked by later deposits ranging in age from Jackson and Vicksburg to perhaps Pleistocene. The red, rather coarse sands that underlie the Vicksburg and overlie the recognizable McBean may be the westward continuation of the Barnwell sand, but as no fossils have been obtained from the sands between Ocmulgee and Chattahoochee rivers, a positive correlation with the Barnwell sand of the Savannah drainage can not be made.
Perry, Houston County-Strata four and one-half miles south of Perry on the Perry-Elko public road, have been referred to the Claiborne group by Dr. Vaughan, who has furnished the following section and list of fossils.
"On the top of Mossy Hill, four and one"half miles south of Perry, Pecten perplanus and Cytherea sobrina were found in the chert. These fossils indicate that the northern slopes of Mossy Hill", from the summit of the hill to 45 feet below the summit, are covered by the Vicksburg formation.

Section down Mossy Hill along an old road leading to the northwest.

Oligocene.

Vicksburg formation.

7. Brownish or reddish soil with chert. Vicksburg

fossils ..... .

20

Eocene

Jackson formation ?

6. Brownish soil, underlying material concealed .

5

5. Gray clay . . . . . . .

4. Mostly concealed . . . . . . . . . . . . . .

10

3. Gray clay . . . . . . . . . . . . . . . . . .

5

McBean formation.

2. Limestone ledges with Claiborne fossils, list

follows . .

5

1. Gray or buff clay

5

Total . . .

50

Fossils from Mossy Hill.

Flabellum cuneiforme Lonsdale Turbinolia pharetra Lea Endopachys maclurii (Lea) Turritella carinata Lea x Mesalia vetusta (Conrad) X Calyptrea aperta ( Solander)
Dentallium thalloides Conrad Nucula ovula Lea Leda sp.

Leda sp.

Glycymeris idoneus (Conrad)

Phacoides alveatus (Conrad) x

Venericardia, 2 or 3 sp.

Cytherea sp.

Crassatellites sp.

,

Corbula oniscus Con. or wallesiana

Harris

Corbula densata Conrad ?

Geologic horizon.---Claiborne. "x" not known from the Jackson."

A list of the species in a collection by Prof. McCallie from this locality, as furnished by Dr. Vaughan, is as follows:

McBEAN FORMATION

259

Fossils from Perry-Elko public road, four and one-half miles south of Perry, Houston County.

Turbinolia pharetra Lea Flabellum cuneiforme Lonsdale Plejona petrosa (Conrad) Levifusus trabeatus Conrad Turritella carinata Lea x Mesalia vetusta (Conrad) x Dentalim thalloides Conrad Nucula ovula Lea Leda sp. Glycymeris trigonella (Conrad) x

Pteria sp. Phacoides alveatus (Conrad) x Phacoides aff. claibornensis (Con-
rad) x Venericardia planicosta Lamarck Venericardia alticostata (Conrad) x Cytherea sp. Crassatellites protextus (Conrad) x Corbula oniscus Conrad x Pteropsis lapidosa (Conrad) x

"x" not known from above the Claiborne. Pteropsis lapidosa is characteristic of the lower Claiborne.

According to V~atch the beds at this exposure consist mainly o drab, calcareous clay and thin layers o limestone, similar lithologically to the upper part o the Ross Hill section. Fossils were collected at an old quarry about 100 yards west o the public road, and our and one-hal miles south o Perry. The strata forming the upper and lower part o the hill are concealed or poorly exposed. The following is a section by Veatch:

Section at qua:rry, four and one-half miles south of Perry.

Feet. In.

10. Red, residual sand capping the top of the hill .

9. Probably calcareous clay, about .

40

. Quarry exposure:
8. Calcareous clay .

4

7. Limestone.

0 10

6. Drab, calcareous clay, contains calcite nodules. 4

5. Limestone.

1

6

4. Clay.

2

3. Limestone.

1

2. Clay.

2

6

1. Poorly exposed, probably limestone and clay,

about.

20

Both the clay and the limestone contain fossils. The fossils collected rom this locality were rom beds 5 to 8.
Dr. Vaughan submits the following note on Veatch's collections:

Besides material similar to that obtained by Prof. McCallie and myself,

Mr. Veatch obtained specimens as follows:



F'ossils from quarry, tour and one-half miles south of Perry.

Mortonia sp. Clypeaster sp. Pecten perplanus Morton Panopaea sp.

260

GEULOGY OF THE COASTAL PLAIN

Lunulites distans (Lonsdale) Idmonea n. sp. (Identified by Doctor Bassler, who states that it
occurs at various Jackson localities, among them Rich Hill, Crawford County;)

"The paleontologic evidence indicates the presence at this locality of two

horizons, viz.: a lower one of Claiborne age, from which Prof. McCallie

and I collected, and from which Mr. Veatch also obtained material; and an

upper ho~izon of Jackson age, from which Mr. Veatch obtained Pecten per-

planus Morton and the species of Idmonea reported upon by Doctor Bassler.

According to Mr. Veatch, as he could observe no lithologic differences in the

section, he was unable to differentiate the exposure into two formations.

The Barnwell seems to be absent."

.

This exposure of the Claiborne group described in the preceding

paragraph, lies south of and at a higher elevation than the exposure

of the Jackson formation at Ross Hill, three miles south of Perry

(see page 301), indicating that at this locality, as Dr. Vaughan sug-

gests, there has been either a fold or a fault in the strata or that the

Claiborne here represents an erosion knob. The natural exposures in

the neighboring areas aTe very poor, the contact between the higher

formations and the Claiborne being concealed, so that it is impossible

t) make dip observations.

Flint River.-A small area of rock, exposed in the bluffs of Fli~t River in the southern part of Dooly and the' eastern part of Sumter counties, belongs to the McBean formation.
The following is a section of a bluff near the old Danville ferry, located 16~,Z miles east of Americus, and one mile above the present ferry on the Americus-Drayton road. The bluff is on the right side of the river and is 50 feet high.

Section at old Danville Ferry, Flint River.

Pleistocene terrace deposit.

6. Yellow, sandy loam, grading down into light mot-

tled, sandy residual clay . . . . .

7

Oligocene.

Vicksburg formation.

5. Sand, coarse to fine, variegated in color, with

scattered fragments of flint; contains residual

clay. . . . . . . . . . . . . . . . . . .

23

Eocene.

McBean formation.

4. Soft, calcareous sand and sandy limestone .

8

3. Layer of indurated limestone containing Pecten,

Mortonia and an oyster . . . . . . . . . . . 2

2. Soft, glauconitic shell-marl . . . . . . . . . . . 2

1. Compact, sandy limestone with rows of limestone

concretions in places becoming an argillaceous

marl with varying amounts of glauconites .

8

Dr. Vaughan furnishes the following note:

McBEAN FORMATION

261

"Dr. L. W. Stephenson made a collection at this locality and obtained the following fossils:

Fossils from old Danville" Ferry.

Endopachys maclurii (Lea) Mortonia lyelli (Conrad)
Turritella carinata Lea Calyptrea aperta (Sol.) Nucula ovula Lea Ostrea sellaeformis Conrad
Pecten lyelli Lea

Phacoides alveatus ( Conrac:t) Phacoides cariniferus (Conrad) Miltha claibornensis (Conrad) Tagelus ? sp. Corbula oniscus Conrad
Lunulites distans Lonsdale

"It seems possible that two horizons may be represented in this collection, as Ostrea sellaetormis is not known to range upward to the upper Claiborne, and Lunulites liistans is not known to range downward below the upper Claiborne. Miltha claibornensis is so far as at present known confined below the Gosport horizon of Alabama. A part of this section is positively the equivalent of the Lisbon horizon of Alabama, and that portion of Shell Bluff below the Ostrea georgiana bed."

Claiborne strata appear at Penny Bluff, 12 miles west of Vienna, and about one and one-half miles above old Danvill3 Ferry.

Section at Penny Bluff.

Pleistocene (terrace sand)

Feet.

4. Gray incoherent sand

2 or 3

Eocene.

McBean formation.

3. Fossiliferous, thin-bedded sandstone; disinte-

grates into thin slabs which cover the face of

the bluff and partly obscure the bed in the

lower part . . . . . . . . . . . . . . . . . . 6

2. Greenish and drab sandy clay, contains calca-

reous nodules in places . . . . . . . . . . . 8

1. White, semi-indurated calcareous sand. Has a

pitted appearance and shows root-like or

fucoid-llke protuberances. Large Ostrea geor-

giana occur in this sand, as well as masses of

comminuted shells . . . . . . . . . . .

3

Fossils frorn Penny Bluff.

"Turritella sp. OalY'Ptrea aperta (Sol.) Leda sp.
Area rhomboidella Lea Ostrea georgiana Conl.'ad

Venericardia pianicosta Lamarck Venericardia alticostata (Conrad) Cytherea Mactra Corbula, etc.

Spencer' gives the following .description of the Flint River Claiborne:

"Along the Flint River the Claiborne beds are well marked; commencing in the bluff just above the old Danville ferry. This bluff is over half a mile long and is composed of alternate layers of hard and soft sandy limestones, with beds as much as four feet thick, the softer beds having a more marly and clayey appearance. The rock is of a greenish or yellowish-white

'Report of progress: Geological Survey of Georgia, 1890-1891, pp. 51, 52.

262

GEOLOGY OF THE COASTAL PLAIN

color, its surface weathers into somewhat rough, but hardly jagged forms. which are so characteristic of certain beds of an overlying cherty formation. These Claiborne beds are well characterized by Ostrea sellaetormis, which are most abundant at the base of and in the harder ledges. In these bluffs the limestones rise to somewhat over 20 feet above the water and they are capped by an equal thickness of superficial sands and loams.
"Above and below the mouth of Ebenezer Creek, upon the left bank, excellent exposures occur in steep bluffs rising to 15 or 20 feet above high
water. Here, the beds appear for considerable distances as quite horizontal. but again suddenly bend down at steep angles, which are rollowed by a
return dip, thus producing undulations. The hard ledges stand out in bold relief, and the softer have a clay-like appearance. In some or the beds these harder layers form the larger proportions of the mass; in others but a small proportion.'

Chattahoochee River.-According to Langdon1 the Claiborne extends from the mouth of Yantayabba Creek, Ala., to a point near Gordon, Ala., a distance approximately 25 mileh air-Jine.
Langdon's description from the base upward follows:

(Base)

Feet.

57. Plain buhrstone, rather sandy. . . . . . . . . 40

58. Light, yellowish green sand containing numbers

of small Ostrea sellaetormis . . . . . . . . 45

59. Buhrstone, supposed summit of the series . . . 55

60. Greenish-yellow, calcareous clay with a few de-

composed fossils and an occasional large

Ostrea se!laetormis . . . . . . . . . . . . . 12

61. White, sandy limestone, with Ostrea sellaetormis

in abundance, and pockets of large-sized shells.

Makes capping ledge to island at mouth of

Omussee Creek, where the bluff is about

twenty feet high. This stratum is made up of

alternate beds of hard and soft strata, all con-

taining more or less Ostrea sellaetormis. The

harder strata weather out into root-like shapes

and are sometimes rather argillaceous. Many

return dips occur in this stratum stringing it

along the banks for many miles further than

it would be normally. The dips are all steep

both ways and many gaps in the succession are

caused by the washing out of the soft strata.

Owing to these gaps and return dips it is

rather hard to estimate the thickness of the

stratum with much accuracy. It dips below

the surface of the river two miles below

Gordon, Ala., and is last seen on the Georgia

bank. At Gordon there is a very pronounced

return dip, estimated at and not exceeding . 60

62. The "Scutella bed" weathers so as to make it not

possible to count up its thickness. It is liter-

ally full of fossils, mainly Scutel!a lyelli and

Pecten nuperus with a few smaller and

thicker Scute!la. A bluff about 20 feet high

occurs opposite the mouth of Sowhatchee

Creek, Ga. . . . . . . . . . . . . .' . . . 25 to 30

1Qeology of the Coastal Plain of Alabama : Geol, Survey of Alabama, 1894, pp, 744, 745.

McBEAN FORMATION

263

Nos. 57 to 61 belong to the Claiborne group and represent the Mc-

Bean formation. No. 62 is suggestive of the Jackson and the prob-

ability of its being Jackson rather than Claiborne is mentioned by

Langdon.'

'

The following section made by Dr. Stephenson from expos-

ures along a road running east from the town of Fort Gaines reveals

the character of the strata forming the upland above the second ter-

race plain; the base of the section i8 about 105 or 110 :feet above the

level of the river :

Section, Fort Gaines, above the Upper Terrace Plain.

Age ?

Feet.

8. Coarse, red, ferruginous pebbly sand. (Similar ma-

terials extend down over the hill for some distance

-probably creep) about . . . . . . . . . . .

15

McBean formation.

7. Greenish sandy clays, and argillaceous sands, more

or less weathered and mottled, about . . . .

40

6. Compact, fine, greenish-gray sandstone, with fossil

prints. (Fossils collected) about. . . . . .

3

5. Pale green, fine loose sand, about . . . . . . . .

3

4. Compact, fine, greenish-gray sandstone , with fossil

prints. (Fossils conected) about. . . . . . .

3

3. Light green, compact, finely arenaceous clay about . . 7

2. Fine, green sandstone, about . . . . . . . . . . . . 3

1. Greenish clays and sands, more or less weathered and

mottled, about .

65

Total, about . . . . . . . . . . . . . . . . . . . . 140

Fossils collected from 55 to 65 feet below the top of the hill W('n identified by Dr. Vaugh an as follows:

Plejona sp.
Turritella sp. Leda pharcida Dall ? Venericardia planicosta Lam.

Miltha claibornensis (Conrad) Cytherea sp. Solen lisbonensis Aldrich ?

On the basis of these fossils the strata Nos. 1 to 7 ~re referred to the McBean formation. The age of bed No. 8 in the section is in <bubt. Similar red sand which contains a bed of Ostrea divaricata was observed southward.
The McBean formation also appears in Chattahoochee River bluff at Fort Gaines. The base of the Claiborne is 50 to 55 feet above mean stages of the river. The rock is a drab, laminated clay or clay stone, and gray, fossiliferous sand. For sections of the bluff and fossils see pages 231-233. The fossils Ostrea sellaeformis Conrad and Pecten lyelli Lea were obtained about 40 feet below the top of the section, or 12 to 14 feet above the base of the McBean formation.
There is an interesting locality at the mouth of Omussee Creek, a

10p cit., p, 383.

264

GEOLOGY OF THE COASTAL PLAI~

short distance below Columbia, Ala. A small, triangular island capped with brown marl and covered with specimens of a large, saddle-shaped oyster, Ostrea sellaeformis, lies adjacent to the creek's mouth. The capping rock is a brown, compact marl, granular in appearance, and very similar to much of the Claiborne marl on Savannah River. It is composed of fine angular quartz sand and white or yellow clay cemented with calcium carbonate; there are small seattered grains of glauconite and phosphate. This bed is three and one-half feet thick and forms a projecting ledge over the lower bed. On account of the high water in the river only seven feet of the lower bed was exposed when visited by the writers. The bed is ashcolored or bluish, soft and contains more clay and less sand and calcium carbonate than the capping rock. A hard, siliceous limestone overlain by red and vari-colored sand was observed a short dis-
tance up the creek from the island. A similar limestone appears
near the wagon bridge over the river, on the Georgia side. A good collection of fossils was obtained from a sandy fullers
earth-like clay, two and one-half miles east of Fort Gaines.

Section of hill along public road to Edison, two and one-half miles

east of Fort Gaines.

Age?

Feet.

8. At the top of the hill, structureless, deep red sand, at

surface; light colored and yellowish in fresh ex-

posures . . . . .

30

Mc.Bean formation.

7. Greenish, laminated clay .

2

6. Sand. . . . . . . . . . . . .

3

5. Drab, laminated clay (fossils collected) and aluminous

soft sandstone; black clay layers at the base; frag-

ments of stems and leaves . . . . .

15

4. Clay and sand, about . . . . . . . . .

5

3. Black, sulphurous, sandy clay . . . . .

4

2. Aluminous sandstone, prints or fossils

21,{!

1. Concealed to level of creek . . . . . .

4

Fossils collected from No. 5, and identified by Dr. Vaughan, are as follows:

Fossils from layer No. 5 in preceding section.

Plejona petrosa (Conrad) Plejona sayana (Conrad)
Led a Barbatia cuculloides (Conrad)
Barbatia rhomboidella (Lea)
Anomia Leda pharcida Dall.

Venericardia sp. Cytherea discoidalis Conrad
Metis raveneli (Conrad) Tellina mooreana Gabb Mactra Pteropsis lapidosa Conrad

"This represents the lower portion of the Alabama Claiborne." T. W. V.

McBEAN FORMATION

265

There seems to be a lithologic gradation from the upper red sand to the lower sandy clay. The tops of the hills are about 300 feet above the Chattahoochee River.. At Mount Vernon church, four and "one-half miles east of Fort Gaines, an erosion remnant of orbitoidal ~hert was found overlying the Claiborne red sand. At Fort Gaines the thickness of the Claiborne group must be nearly 200 feet.
Near Neves mill, on the south side of Colomokee Creek, seven miles south of Fort Gaines, a thin, unconsolidated bed of small Ostrea divaricata shells occur in the upper red sand of the Claiborne group and laminated drab and black clays form the basal part of the section. Still farther south the basal clays of the Claiborne group become more calcareous and are partly replaced by limestone and marl.
At Grimsley's mill, 13 miles south of Fort Gaines and about two miles east of the Chattahoochee River, characteristic lower Claiborne fossils were collected. The generalized section here is as follows:

Generalized section at Grimley's Mill.

Feet.

Age? 3.

Red sand ...

. 50 to 75

Eocene.

McBean formation.

2. Interbedded clayey marl, and bluish or drab fullers

earth-like clay; Ostrea divaricata, Pteropsis lapidosa,

Oalyptrea aperta . . . . . . . . . . . . . . . 15 to 20

1. Soft, argilaceous marl and limestone . . . . . . . . . 10

A marl exposure was visited on the farm of W. C. Hutchins, on Chattahoochee River, nine miles west of Blakely. From a number of exposures it is inferred that the beds underlying the first terrace plain which lies 35 or 40 feet above the river, are bluish and ashcolored sandy marls and clays and beds of sandy limestone, overlain by Pleistocene sands and clays. Red sand containing thin beds of broken shells appears in the scarp of the upland.
The following is the columnar section of the Claiborne group at this locality:

Section on farm of W. G. Hutchins.

Feet.

10. Red sand, often highly ferruginous, appears on the

higher land . . . . . . . . . . . . . . . .

?

9. Thin bed of. comminuted shells, 0. divaricata .

1

8. Red sand . . . . . . . . . . . . . .

12

7. Unconsolidated bed of sand; layer of loose shells, 0.

divaricata . . . . . . .

2

6: Red quartz sand . . . . . .

12

5. Bluish argillaceous sand . .

12

266

GEOLOGY OF THE COASTAL PLAIN

4. Sandy limestone . . . . . . . . . . . . . . . . . . I
3. Bluish and drab sandy laminated clay . . . . . . . 1
2. Marl bed, composed of shells, teeth, bones, in a r 40
matrix of calcareous, glauconitic clay and sand . 1
1. Hard sandy limestone . . . . . . . . . . . . . . . J
Strata of the character of that from 1 to 4 underlie the first terrace plain and have a total thickness of about 40 feet. The strata Nos. 5 to 9 were observed along the public road east from Mr. W. C. Hutchins residence.
Other localities.-Eastward from Fort Gaines but few fossiliferous localities have been found, and the strata mapped as Claiborne were determined to be such, mainly on the grounds of their lithologic character, stratigraphic position between known Vicksburg and Wilcox strata, and the presence of erosion unconformities separating the formation from the two formations mentioned.
The Claiborne red sands at Fort Gaines were traced northeastward to Cuthbert, where there is a thickness of only 50 or 75 feet. Unconformable relations with the overlying Vicksburg formation were observed in the cuts of the Central of Georgia Railway, two miles west of Cuthbert, and an unconformity believed to separate it from the Wilcox formation was found in the cuts three miles w.est. At the old quarries one mile northwest, there is a soft aluminous sandstone and laminated drab clay, overlain by fine red sand, probably Claiborne. The soft sandstone contains a few fossils; Dr. Vaughan identified Turritella probably carinata.
The fine variegated sand which is exposed in the vicinity of Shellman is referred to the Claiborne group. Flint fragments of the Vicksburg formation imbedded in sandy clay, quite different from the underlying Claiborne strata, are found on the higher land, while a few miles northward from Shellman irregular contacts with tlte underlying Wilcox formation were found. The Claiborne sand comains very little clay, but in a few places contains beds of brown or black limonitic sandstone. This soft sandstone was used in the abutments of the Central of Georgia Railway trestle over Ichawaynochaway Creek, two miles east of Shellman. No fossils were found, The thickness in the vicinity of Shellman is probably 100 to 150 feet.
At Cordray Mill, on Ichawaynochaway Creek, 12 miles east of Edison, a calcareous, aluminous sand, slightly indurated, occurs in the bed of the creek. This material contains a few clay fossil casts and fragments of an oyster shell, and probably belongs to the McBC'an formation. At Bateman "Hammock," one and one-half miles Ldow the mill, there is an exposure of about one foot of clayey sand and sandstone which contains Ostrea divaricata. Above this bed there are three feet of hard, sandy limestone, containing a species

McBEAN FORMATION

267

of Pecten, Bryozoa, and fragments of a large oyster. There is some pl'obability that this limestone bed belongs to the Jackson formation.
At Parrott, Terrell County, the high ridge followed by the Seaboard Air Line Railway is capped with red sandy clay containing residual fragments from the Vicksburg formation, but both to the east and west on the lower land, there are red and yellow incoherent sands quite different from the Vicksburg materials, and probably referable to the Claiborne groups. At Walker's Mill on Mossy Creek about one and a half miles southeast of Parrott, there is an exposure of aluminous sandstone, quartzite, and drab claystone overlain by red sand, similar to the section of the Claiborne group at Fort Gaines.
What is probably the McBean formation was found in a bluff of Kinchafoonee Creek, near Hall's Bridge, four miles southwest of Smithville. The rock is a hard, aluminous, calcareous quartzite, and white, :flaggy sandstone similar to that at Penny Bluff, Flint River. The fossils are not well perserved but are suggestive of the Claiborne. About six feet of hard rock is exposed and is overlain by red sand.
The Claiborne group in the vicinity of Americus, and south of Andersonville, consists principally of quartz sand, in places highly ferruginous. Unconformities with the overlying Vicksburg formation may be seen in railway and road cuttings in and near the city of Americus. Bluish, sandy clay and sandy, glauconitic marl and sandstone, doubtless in the Claiborne group, are encountered in well borings at Americus.

CONGAREE CLAY MEMBER OF McBEAN FORMATION

The term Congaree, as has been stated, is adopted from South Carolina. Sloan1 defines the Congaree as follows:
"The Congaree phase is abundantly exhibited in the western Tertiary division along a curved line extending by Aiken, Sandy Run (on the Congaree), Wedgefield, and thence down the eastern side of Santee River; it is also characteristically exhibited along the belt extending from Wedgefield towards the eastern division north of the Carolinian ridge. East of the latter the Congaree phase is probably exhibited in thin shales tnterlaminated with sands along the western bluffs of Peedee River."
Again quoting Sloan :
"The Congaree phase exhibits its littoral line along Hollow Creek near Savannah River and proceeds with occasional tongues extended in conformity with the shore-line indicated for the Tertiary. The main line proceeds from McBean Creek Valley, Ga., by Beech Island, Aiken, Perry, Horsey's Bridge, and Gaston, to the vicinity of Congaree Bluff."
1Catalogue of mineral localities of South Carolina: Geol. Survey or South Carolina,
p. 4o5p4.. cit., p. 455.

268

GEOLOGY OF THE COASTAL PLAIN

Lithologic descriptions of the Congaree near Gaston, S. C., and Congaree Creek are given by Sloan.1
The Congaree as described in South Carolina and the member to 1rhich this term is applied in Georgia are regarded as equivalent. Both lies at the base of the Claiborne group and have a close lithological similarity. The clays of this member in Georgia rest directly upon the Lower Cretaceous, and are separated from it by conspicucus erosion unconformities of regional extent; striking differences in lithologic character and the presence of fossils in the former afford <:n easy means of distinguishing between the two.
Faunally the Congaree clay member does not seem to differ from the lower faunal horizon of the marl of the McBean formation. It seems probable that the clays represent a shoreward phase, or that the Congaree clay member becomes more calcareous southward and gradually merges into the marl. In most of the sections studied, the day and fullers earth seem to pass by gradation upward into the Barnwell sand. There are, however, some unconformities between the two and abrupt changes in the character of the strata; these may be of only local significance, such as might take place in a shallow water deposition.
The fullers earth is drab or gray, often appearing olive-green when moist, fine-grained, thinly-bedded, and minutely jointed. It is generally sandy and contains small sand lenses and pockets, and has thin, micaceous sand partings ; the earth is soft, unctuous, and breaks with a smooth, conchoidal fracture. It poo'sesses a low specific gravity and peculiar physical properties,-thin pieces of the dry earth are light enough to float on water; it is highly porous, and adheres strongly to the tongue. In a few places the Oongaree clay member contains a large amount of disseminated, lignitic matter, and thin beds of lignite, as at the lignite pit, three miles south of Grovetown, which will be subsequently described. Thin-bedded shale-like, aluminous sandstones and dense, vitreous quartzites were observed near the base of the member at Hephzibah, Wrens, Gibson, Chalker, and Dther localities. At a number of localities greenish or drab, stiff, or iN1gh clays, showing little or no lamination and attaining a thickness of 80 or 100 feet, lie in contact with the Lower Cretaceous. In places the materials consist of alternating layers, a few inches thick, of clay and vari-colored sand.
The clay and fullers earth beds reach a thickness of at least 100 feet. This member contains abundant fossil remains in a few places, though on the whole, it is not so fossiliferous as the marls. The animal remains are mainly molluscan casts, although the clay also con-
lOp. cit., pp. 346, 347.

McBEAN FORMATION

26!t

tains thin marly layers in which shells occur in quantity, and in which fish teeth and fragments of bones are found. Plant localities have been discovered at Grovetown, Hephzibah in Richmond County,. and 10 miles south of Macon in Bibb County. This member is not paleontologically distinct from the McBean formation.
There are numerous outcrops of the Congaree clay member from Grovetown southwestward along the Fall Line to Bibb and Twiggs counties. It is confined to the northern part of the area of the outcrop of the McBean formation, but no sharp line separating the member either from the marls of the McBean formation to the south or the overlying Barnwell sand can be drawn. The most prominent and typical exposures are at Grovetown, Harlem, Gibson, Gordon, Roberts, and Pikes Peak in Twiggs County. The clays have had no marked influenee on the soil and vegetation, and outcrops appear mainly in gullies and ravines where the overlying red sands have been eroded.

LOCAL DETAILS

COLUl\iBIA COUNTY

Grovetown.-Grovetown is located on the Georgia Railroad 15 miles west of Augusta. Fullers earth and clay of the Congaree clay member of the McBean formation are exposed at a number of place::: in this vicinity.

Section at the old fullers earth mine.

Eocene.

Barnwell sand.

Feet.

3. Red, pebbly sand . . . . . . . . . . . . . . . . . . . 5+

McBean formation (Congaree clay member).

2. Fullers earth, gray or drab, laminated; contains bits of

wood and has fine sand partings and pockets.

10-12

Lower Cretaceous

1. White clay, full thickness not exposed . . . . . . . . 4+

The fullers earth is also exposed in the cnt at the railroad station,. where there is four feet of fullers earth overlain by 10 feet of red, pebbly sand. It is probable that both the clay and sand belong to the Claiborne group. There is apparently a very slight unconformity between the sand and clay. In the first cut south of the station there is an exposure of 20 feet of sand which evidently overlies the fullers earth, and belongs to the Barnwell sand.
About one-quarter mile west of Forest, casts of fossils are abundant, in an aluminous sandstone. Underneath the fossil layer is a thin, shaly bed resembling the fullers earth at Grovetown, and at a still lower leYel there is a prominent exposure of arkose or kaolinic

270

GEOLOGY OF THE COASTAL PLAIN

sandstone of Lower Cretaceous age. This locality has been visited by Prof. G. D. Harris1 of Cornell University, who noted oyster fragments. and a species of Modiola, but no definite horizon for the strata was g1ven.
About three-quarters of a mile west of Forest on the old Fiske place there is a yellow, ochreous, shaly earth, which contains casts of fossils, and is evidently the equivalent of the Grovetown fullers. ,earth, and belongs to the Congaree clay member. This is overlain by red, pebbly sands.
In a gully on the Phinizy land, on the Augusta and Wrightsboro public road, about one mile east of Grovetown, a laminated fullers earth fills an erosion hollow in the Cretaceous. The locality is notable for the clear-cut exposure of the unconformable relations of the two formations. The fullers earth contains impressions of leaves, stems, and palms, the determination of whi<:<h may be of considerable stratigraphic interest.
The fossils recorded in the following list were determined by Dr. Vaughan from a collection made by Prof. McCallie, in the Fiske clay pit:

Fossils from Fiskes clay pit.

Nucula magnifica Conrad Nucula ovula Lea Leda 2 sp. Balanus sp.

Turbinella (Psilocochlis) mccallle.i
Dall Ostrea Modiolus texanus Gabb Calyptrea aperta (Solander)

Lignite and lignitic clay belonging to the Claiborne group appear at the lignite pit of the Georgia Lignite Mining Company, three miles south of Grovetown.

Section of Lignite pit.

Barnwell sand.

Feet.

12. Beginning at top. Grayish or brownish incoherent

sand . . . . . . . . . . . . . . . . . . . . . . . . 3 or 4

11. Red, coarse, quartz sand . . . . . . . . . . . . . . . 8 to 10

10. Laminated clay layer . . . . . . . . . . . . . . . . .

2

9. Coarse, angular, yellow quartz sand; contains limonite

fragments, in places small gravel . . . . . . . . .

15

8. Red, brown, and purplish crossbedded sand; scattered

small pebble~; some thin clay layers a few inches

thick; uneven contact between this sand and the un-

derlying lignitic clay . . . . . . . . . . . . . . .

35

McBean formation (Congaree clay member).

7. Pink and white, plastic clay, partly removed by

erosion . . . . .... .

1

6. Lignite . . . . . . . . . . .

2

5. Drab, clay, some lignitic material

2

- 1-B-ul-l.-Amer. Paleontology No. 6, Dec. 8, 1902, p, 7.



I


McBEAN FORMATION

271

4. Lignite; large lignitized logs. 3. Drab clay . . . . . . . . . . . 2. Lignite. . . . . . . . . . . . 1. Lignitic clay . . . . . . . . .

Feet. 4 1 1 2

The lignite and lignitic clays were penetrated in a nearby shaft, and were found to have a thickness (reported) of 15 feet. Coarse, quartz sand conatining white clay, evidently Lower Cretaceous, unlerlies the lignitic beds. The similarity of the sections leaves no doubt that the lignite and lignitic clay are the equivalent of the fullrs earth at Grovetown. The sand in the section represents a shoreward aspect of the Barnwell sand.

This locality was described by Lewis' in 1880 who regarded the formation as contemporaneous with the Brandon formation of V ermont and Pennsylvania. As Professor Knowlton has, from a study of the fossil flora at Brandon, concluded that the age of that deposit is probably Miocene, Lewis's correlation is known to be erroneous.

Harlem.-The succession of beds and the character of the strata in this vicinity are essentially the same as at Grovetown and vicinity.
The following section is revealed at the plant of the Georgia Vitri.ned Brick & Clay Company, one and a half miles east of Harlem:

Section at plant of Georgia VitrifierlJ Brick and Clay Company.

Eocene.

Feet.

Barnwell sand.

7. Red and yellow, highly ferruginous sand; contains

siliceous limonite fragments, covered with a thin

veneer of gray sand . . . . . . . . . . . . . . . . 25

6. Yellow sand, pebbly; fragments of silicified wood . . . 8

McBean formation (Congaree clay member)

5. Yellow and white sandy clay . . . . . . . . . . . . . 5

4. White, massive, sandy clay; contains bits of carbonized

leaves and wood . . . . . . . .

7

3. Black, carbonaceous, jointed clay . . . . . . . . . . . 4

2. Concealed, a few feet . . . . . . . . . . . . . . . . . ?

Lower Cretaceous.

1. Massive, indurated, white. clay, having the lithologic

aspect of the Cretaceous white clay . . .

12

Section at Phillip's Falls, one and one-half miles southwest of Harlem.

Barnwell sand.

Feet.

. 5. At top of section, red sand . . . . . . . . . . . . . . 10

McBean formation ( Congaree clay member).

4. Bluish and gray, laminated fullers earth, fragments of

plant remains . . . . . . . . . . . . . . . . . 20 to 30

3. Sandy clay, evidence of fossil plants >but no well pre-

served forms were found . . . . . . . . . . . . . . 3

'Clark, W. B., Bull. U. S. Geol. Survey Xo. S3, p. fl4.

272

GEOLOGY OF THE COASTAL PLAIN

2. Massive bed of gray to bluish gray indurated clay;

not laminated . . . . . . . . . . . . . . . .

10

1. Coarse, quartz sand, containing large chunks of white

clay . . . . . . . . . . . . . . . . . . . . . . . . 10

A small exposure o lignite and dark lignitic clay also occurs along: a small stream on the south side o the railroad, on the old Lucky place, about three-quarters of a mile from the station at Harlem. This is overlain by 12 feet or more of fullers earth and red and yellow limonitic sand.

JEFFERSON COUNTY
Wrens.-A peculiar claystone, together with a shaly, aluminous sandstone, was found at R. R. Hatcher's mill on Reedy Creek, five miles north of Wrens. The shaly sandstone contains fragments of lignitized wood and stem and lea impressions. The hard clay is bluish-white in color, compact, breaks with a conchoidal or angular fracture, and is almost entirely free from sand. A chemical analysis shows the proportion o silica ( 65.21 per cent.) to alumina (21.62 per cent.) to be much greater than that of the hard white clays o the Cretaceous. The clays here are overlain by red,. pebbly sand representing the Barnwell sand.
At Patterson's Bridge on Briar Creek, six miles north of Matthews, there is 10 feet of sandy, laminated fullers earth, with which is, associated some silicified clay similar to that at Hatcher's :1\Ell. A short distance south of the bridge there is an outcrop of quartzite containing fossils. The exact relations of this quartzite to the fullers earth could not be determined, but it is inferred that it lies above the fullers earth.
At Wrens old mill, two miles south of Wrens, about 25 feet of sandstone and quartzite appears. This rock contains oyster shells that could not be specifically identiied. On the road between Wrens and Matthews outcrops of vitreous quartzite and laminated clays were noted. These outcrops probably belong to the Congaree clay member.
GLASCOCK COUXTY
Gibson.-There are a number of good exposures of the Claiborne group in the vicinity of Gibson. The group lies unconformably upon the Lower Cretaceous and is divisible into two formations, as. indicated in the following section:

GEOLOGY OF 1'HE COASTAL PLAIN OF GEORGIA.

PLATE XX.

A. FL'LLERS EARTH IN CONGAREE CLAY MEMBER OF McBEAN FORMATION, PIT OF GENERAL REDUCTION CmlPANY, TWELVE :\1ILES 0 THEAST OF MACON, IN TWIGGS COU 'TY.
B. CUT OF MACON. DUBLIN & SAVANNAH RAILROAD. PIKES PEAK STATION. TWIGGS COUNTY, SHOWING CO 'GAREE CLAY MEMBER OF )lCBEAN FORl\IATIO .

McBEAN FORMATION

273

Section at the J. Newsome property) three miles east of Gibson.

Eocene.

Barnwell sand.

6. Red, crossbedded sand capping the hill .

30

McBean formation ( Congaree clay member).

5. Massive; drab, and greenish clay . . . .

20

4. Soft, fossiliferous limestone . . . . . . .

5

3. Calcareous sandy clay . . . . . . . . .

5

2. Sand, containing large pellets of white clay .

15

(Unconformity)

Lower Cretaceous.

1. White clay or kaolin . . . . . . . .

An instructive exposure appears along the Gibson-Mitchell road at Jumping Gully Creek, one mile west of Gibson.

Section at Jumping Gully Creek.

Eocene.

Barnwell sand.

Feet.

5. At the top of the hill, fine, red, argillaceous sand .

10+

McBean formation (Congaree clay member).

4. Gray laminated clay, somewhat in the nature of fullers

earth . . . . . . . . . . . . . . . . . . . . . . . 10

3. Laminated, sandy, clay , containing thin limonitic,

crusts; very fossiliferous. Fills narrow "V" shaped

erosion gullies in the underlying white clay .

3

Lower Cretaceous.

2. White clay . . . . . . . . . . . . . . . . . . . . . . 10

1. Talus to level of creek . . . . . . . . . . . . . . . .

From bed No. 3 the Claiborne fossils, Flabellum cuneiforme) Turritella ca?"inata) and M esalia vetusta have been collected.

Prof. :McCallie collected fossils at the English plantation, one and one-half miles north of Gibson. These have been identified by Dr. Vaughan, who furnishes the following list and annotation:

Fossils from the English plantation.

Flabellum cuneiforme Lonsdale Endopachys maclurii (Lea)
Mazzalina inaurata Conrad Turritella carinata Pecten wilcoxii Dall ? Pteria sp. (the internal mould of a
rather large species)

Venericardia planicosta Laimarck Venericardia alticostata (Conrad)
Lucina sp. Panopaea aff. oblonga Conrad
Cytherea sp.

"The matrix is a light gray, in some instances blotched yellow, indu rated sandstone, some pieces considerably silicified.
"The fauna is Claibornian but whether upper or lower could not be Jetermined from the fossils submitted."

Good exposures appear in road cuttings and gullies south and sonth,Yest of Gih~on.

274

GEOLOGY OF THE COASTAL PLAIN

Section at Tompkins Ford on Grange road, four miles south of Gibson.

Eocene.

Barnwell sand.

Feet.

6. At top of hill, red sand . . . . . . . . .

10

5. Sandstone or quartzite containing fossils .

4

4. Red sand, fine-grained, and argillaceous . .

15

McBean formation (Congaree clay member).

3. Massive, stiff, tenacious, greenish or drab clay; massive

surface aspect may be due to weathering . . . . . . 30

Lower Cretaceous.

2. White, massive, semi-indurated clay, distinguished from

that above 'by its much greater purity .

15

1. Soft clay and sand conglomerate . . . . . . . . . . .

WASHINGTON COUNTY
Sandersville.-Limestone occurs near Sandersville, which will be discussed later. A considerable thickness of clay and sand is exposed north and west of Sandersville, while at Sandersville and southward limestone and calcareous strata occur.
The following section was observed along the upper Milledgeville road on the descent to Keg Creek, six miles west of Sandersville.

Section St-x miles west of Sandersville.

Eocene.

Feet.

Barnwell sand.

4. At top of the hill, bright, red sand, hardened at the sur-

face by iron oxide cement. Fresh exposures show

yellow and red, coarse, unconsolidated sand . . . . 60

3. Red sand, containing gray, waxy, clay laminae. The

clay is in layers often not more than one-half or one

inch thick . . . . . . . . . . . . . . . . . . . . . 20

McBean formation (Congaree clay member.)

2. Gray, greenish or drab clay, tough and waxy where

weathered; fresh exposure laminated in the nature

of fullers earth; apparent gradation between.. this

and the overlying sand . . .

45

Lower Cretaceous.

1. Hard, massive, white fireclay . . . . . .

16

Sand and clay, which can be correlated with that in the foregoing section, appears in a deep gully to the north of the J\iilledgeville road, four and one-half miles west of Sandersville.

Section four and one-half miles west of Sandersville.

Eocene.

Feet.

Barnwell sand.

5. Red sand at top of gully . . . . . . . . . . . . . . . 15

4. Lighter colored sand . . . . . . . . . . . . . . . . . 10

McBean formation ( Congaree clay member).

3. Laminated, fullers earth-l_ike clay, becomes gandy at

top, and there is an apparent gradation between 3

and 4. . . . . . . . . . . . . . . . . . . . . . . 20

McBEAN FORMATION

275

2. Marl layer, a fossiliferous, bluish mud, and in places a bed of comminuted shells (Claiborne fossils) . . . . 3
1. Bluish mudstone . . . . . . . . . . . . . . . . . 15

At the Carter Mill site, our and one-hal miles north o Sandersville, the following succession o beds was observed:

Section five and one-half miles north of Sandersville.
Eocene. Barnwell sand. 4. Red sand, contains a siliceous, fossiliferous rock . . . 3. Coarse quartz pebble conglomerate, a few feet m thick ness . . . . . . . . . . . . . . . . . . .. McBean formation (Congaree clay member). 2. Laminated clay and argillaceous sand, the latter prob ably reworked Cretaceous .
Lower Cretaceous. 1. Massive, white, fire clay . . . . . . . . . .

One mile north o this locality the following successiOn was observed in the hill on the public road :

Section six and one-half miles north of Sandersville.

Eocene.

Feet.

J 5. Red sand, in places large, well rounded quartz pebbles 1
4. Red sand, thin beds of greenish laminated clay . . 40 to 50

3, Coarse red sand . . . . .

.

Cretaceous. 2. White massive fire clay . . . . . . . . . . . . . } 1. Typical Cretaceous sand . . . . . . . . . . . .

10+

In a well at Thena, eight miles west o Warthen, 50 eet o laminated, shaly clay, in the nature o fullers earth and containing casts o fossils, was encountered in a well. The underlying Cretaceous is exposed in the valley o Keg Creek a short distance east, and the upland is covered with the red Barnwell sand and gray surficial sand.
A section o a hill on the road to Hebron, seven miles southwest 0f Sandersville shows :

Section seven miles southwest of Sandersville.

Feet.

Eocene.

Barnwell sand.

3. At the top, fine red sand apparently conformable on No.

2. . . . . . . . . . . . . . . . . . . . . . .

10

McBean formation (Congaree clay member).

2. Greenish and drab, massive and laminated clay .

80

Lower Cretaceous.

1. White clay . . . . . . . . . . . . . . . . . . .

4

There appears to be a gradation between 2 and 3 where the sand is superimposed; both clay and sand are in contact with the Cretaceous in exposures west o this locality.

276

GEOLOGY OF THE COASTAL PLAIN

Chalker.-Exposures along the public road, one-half mile south of Chalker, show at the top of the hill, 30 feet of fine, red sand, becoming more argillaceous at the base, and 50 feet of laminated, sandy clay (Congaree clay member) overlying white and yellow sands of the Cretaceous.
In the railroad cut, one mile south of Chalker, a thin-bedded, aluminous sandstone two or three feet thick, at the base of the Tertiary, overlies a white clay bed of the Cretaceous.
From a cut two miles southwest of Chalker, Prof. McCallie collected fossils from a sandstone that directly overlies white clay of the Cretaceous. These fossils have been identified by Dr. Vaughan, who furnishes the following list:

7!'ossils from two miles southeast of Chalker.

Flabellum cuneiforme Lonsdale

Cucullaearca cuculloides (Conrad)

Cerithium ,2 sp. both apparently

new

,

Turritella carinata Lea

MesaUa vetusta (Conrad) Venericardia Ostrea georgiana Conrad-? Cytherea Corbula alabamiensil;! Lea

WILKINSON COUNTY

Gordon..- A number of good exposures of Tertiary _and Cretaceous beds occur in this vicinity. A section made along the public road on the Ezell or W. S. Smith place, one and one-half miles south of Gordon shows:

Section one and one-half miles south of Gordon.

Eocene.

Feet.

Barnwell sand.

5. At the top of the hill, dark, red sand with small quartz

pebbles. . . . . . . . . . . . . . . . . . . . . . . 40

4. Red, orange, and brown sand, contains thin, greenish

clay layers about .an inch in thickness . . . . . . . 15

McBean formation (Congaree clay member).

3. Greenish or drab clay, containing casts of fossils; in

places white, siliceous concretions. The clay is mas-

sive, where weathered, but in fresh exposures is

bedded and resembles fullers earth . . . . . . . . 50

2. Bluish sandy clay with red splotches, due to weathering 10

Lower Cretaceous.

1. White, massive-bedded clay . . . . . . . . . . . . . . 12

The same general succession prevails southward in numerous gullies and road cuts. At a few localities the red sands at the surface seem to overlie the greenish and drab clays uncontormably, but most of these are not true erosion unconformities but are due to "creep" of the red sands down hill slopes.
At Ball's Church, about eight miles south of Gordon, a deeply eroded gully on a hillside shows:

McBEAN FORMATION

277

Section in gully at Ball's Church.

Eocene.

BlairnweU sand.

Feet.

3. Top of hill, dark, red sand. Becomes more argillaceous

at the base . . . . . . . . . . . . . . . . . . . . 70

McBean formation (Congaree clay member).

2. Drab, laminated clay layers, with sand partings. Clay

porous, low specific gravity, and in the nature of

fullers earth . . . .

50

Lower Cretaceous.

1. Massive white clay . . . . . .

5+

Pro. McCallie has furnished a description o a section two miles west o Gordon, on the Gordon-Macon public road, as follows:

Section two miles west of Gordon on public road.

Eocene. Barnwell sand. 9. Stratified, red, sandy clays, upper part massive . 7. Yellowish, stratified sands . . . . . . . . . . .
6. Thin-bedded, tough, drab colored clays . . . . . 5. Thin-bedded, reddish sands with clay partings . McBean formation (Congaree clay member) 4. Fullers earth ( ?) with fossils . . . .
3. Fine, orange-colored sand . . . . . . (Unconformity)
Lower Cretaceous. 2. White clay (kaolin) massive. . . . . . . . . . . . . 1. Massive, micaceous, sandy clay, base of section . . . .

Feet. 10 6 10 3
15 4
4

Fossils from stratum No. 4 were identified by Dr. Vaughan.

Fossils from Stratum No . .!,.!

Platytrochus stokesi (Lea) Plejona petrosa (Conrad)
Nucula ovulia Lea Leda bella Leda sp. ?
Leda sp.

Tagelus sp.
Diplodonta (Sphraerella) aff. inflata Lea
Miltha aff. claibornensis (Con.) Cytherea sp.

Lewiston.-Ladd giVes the following section m a clay pit a.t Lewiston:

Section in clay pit at Lewiston.

Eocene.

McBean formation (Congaree clay member)

Feet.

5. Red and yellow, clayey sand, with seams of laminated

clay; also thin seams of brown iron ore, containing

many coarse pebbles . . . . . . . . . . . . . .

6

1These fossils do not furnish horizon within the Claiborne.-T.

Wsu.ffvic.iently

definite

information

to

determine

the

2Bull. Geol. Survey of Georgia No. 6-A, p. 113.

278

GEOLOGY OF THE COASTAL PLAIN

Feet.

4. Irregular siliceous beds, resembling quartzite, and con-

taining drusy quartz cavities and many fragments

of shells . . . . . . . . . . . . . . . . . . . . . . 4

3. White sand, free from iron stain, cross-bedded in places,

containing mica and kaolin, and also nodules or

fragments of white clay, in the upper surfaces of

which are sharply outlined pear-shaped cavities, each

filled with a yellowish clay. These cavities vary in

diameter from one-quarter to one inch .

7

Lower Cretaceous.

2. White, gritless clay, or kaolin . . . . . . . . . . . . . 2

1. White sand . . . . . . . . . . . . . . . . . . . . . . 2

The white clay is probably Cretaceous; characteristic C1aii)orne

fossils occur in the quarzite at this locality. Prof. McCallie has collected fossils on the farm of J. W. Huckabee,
one and one-half miles west of Lewiston, which have been identified

by Dr. Vaughan as follows:

Fossils from farm of J. W. Huckabee.

"Endopachys maclurii (Lea) Turbinella sp. Turritella carinata Lea Mesalia vetusta (Conrad)
Nucula ovula Lea

Venericardia planicosta L!Lmarck Crassatellites protextus (Conrad)
Corbula oniscus Conrad Corbula alabamiensis Lea

"Although this is clearly a Claiborne fauna the precise horizon within the Claiborne is indefinite."

TWIGGS COUNTY

Pikes Peak station.-Three-quarters of a mile west of Pike Peaks Station, in the Dry Branch region, the formation is more argillaceous than in the foregoing sections, being represented by a heavy .bed of fullers earth. Fossils identified from this locality are Nucula aff. ovula, Ostrea georgiana, Orassatelliles protextus.

Section at General Reduction Company's fullers earth m~ne.

Barnwell sand.
3. Red and white sand . . . . . . . . . . . . . . . 2. Greenish and drab, waxy and tough clay, only
laminated, locally known as "gum" McBean formation (Congaree clay member).
1. .l:Ieavy-bedded fullers earth . . .

Feet. 10
6 to 10
15

No unconformities occur in this pit. In an abandoned pit a si m-

ilar succession appears :

Barnwell sand. 3. Red and white sand, contains thin layers of fossiliferous sandstone . . . . . . . . . . . . . . 2. Greenish, waxy, faintly laminated clay, "gum" from 2 or 3 to 10 or 12 feet in thickness . (Apparent unconformity)

Feet. 15

McBean formation (Congaree clay member). 1. Heavy-bedded fullers earth . . . . . .

10 to25

McBEAN FORMATION

279

The fullers earth is a drab or olive color when moist, becoming almost w;hite when dry. The beds or layers are from a few inches to two or three feet in thickness, and are separated by fine, micaceous sandy partings. The fullers earth itself is sandy and contains circular or lenticular pockets of gray sand reaching two or three inches in their greatest dimensions. The earth is o'Oft, unctuous, very porous, and of low specific gravity; it is minutely jointed and the joint .cracks are filled with limonitic coatings or show thin black scales of manganese dioxide.
The following section appears in the railroad cut at the overhead wagon bridge a short distance southeast of the fullers earth mill:

Section in railroad cut near Pikes Peak Station.

Barnwell sand.

Feet. In.

8. Red sand . . . . . .

4

7. Red and white sand

6

6. Greenish clay

5

5. Drab fullers earth clay, thin layered sand partings 8

4. Yellow sand . . . . . . . . . . . .

0 2

McBean formation (Congaree clay member.)

3. Heavy bedded, jointed earth

6

2. Gray, fossiliferous sand

4

1. Talus ............ .

4

In the first cut beyond the overhead bridge and near Pikes Peak station, a striking unconformity appears between red sand and fullers earth-like clay. The cut shows 10 feet of fine, red sand mantling 25 feet of bedded and jointed fullers earth and clay. The full significance of this unconformity is not known; however, it is believed that the red sand belongs to the Claiborne group.

JONES COUNTY
Roberts Station.-Bluish, fossiliferous mud and thinbedded ~lay in the nature of fullers earth occur in a cut on the Georgia Railroad one mile east of Roberts. This locality was studied by Prof. G. D. Harris,' who referred the strata to the "Woods Bluff" (Bashi) beds of the "Lignitic" (Wilcox). Dr. Vaughan has identified a large number of species from this locality, a greater number than i&
1American P~leontology, Bull. No. 16, 1902, p. 4.

280

GEOLOGY OF THE COASTAL PLAIN

given by Professor Harris, which shows the Claiborne (not Wilcox) age of the beds. There is also lithologic similarity to the Claiborne sections at other nearby localities. This clay represents the Congaree clay member of the McBean formation, and the sand probably the Barnwell sand of the Claiborne group.

Section in cut one mile east of Roberts.

Eocene Barnwell sand ( ?) 6. Beginning at top, loose red sand, contains a few scattered quartz pebbles, no fossils observed . McBean formation (Congaree clay member.) 5. Greenish and drab laminated sandy clay, porous and of low specific gravity . . . . . . . 4. Laminated, sandy clay containing white calcareous nodules and casts of fossils . 3. Bluish, fosiliferous mud
Crystalline basement rock. 2. Concealed a few feet . . 1. Crystaline, igneous rock .

Feet. 8 to 10
12 8 8 ?

The igneous rock does not appear in the deep cut, but outc1ops in the next cut east. There is no evidence of an unconformity between the red sand and the clay. The red sand, No. 6, was traced north from the cut as far as Slocumb on the Central of Georgia Railway. It contains fragmentary beds of quartzite in which are comminuted shells, and since these have no appearance of having been transported there is little doubt about its Eocene age. In the cut about one-quarter of a mile east of the "shale" cut, the red sand, (at the base interbedded sand and clay) is in contact with a decomposed granite and a diabase dike, the latter having a width of about 100 feet. There is no evidence that the dike was intruded in the Tertiary strata.
In the first cut west of Roberts, red sand, containing small fossiliferous, quartzite fragments, appears. In the second cut west, what is probably red Claiborne sand uncomformably overlies gray, micaceous, kaolinic sand of the Cretaceous.
Dr. Vaughan has tabulated the fossils collected in the cut one mile east of Roberts. Collections have been made by G. D. Harris, S. W. McCallie, Earle Sloan, and T. W. Vaughan. The initials above the eolumns indicate the collectors.

McBEAN FORMATION

281

'l'able of fossils from cut on Georgia railroad, one mile east of Roberts, Jones County.

NAME OF SPECIES
Endopachys maclurii (Lea) Cylichna sp. Plejona petrosa (Conrad) Clavelithes sp. Mazzalina sp. Fusus (Levifusus) trabeatus Conrad Chrysodomus striatus ? Pseudoliva vetusta (Conrad) Turritella apita de Greg Turritella nasuta Gabb Turritella clevelandia Harris Turritella carinata Lea . Turritella arenicola Conrad . Natica semilunata Lea Calyptrea aperta (Sol.) Adeorbis sp. Nucula ovula Lea Yoldia aldrichiana Yoldia aff. psammotaea Dall . Leda aff. albirupiana Harris Leda plicata Lea . T,rigonarca sp. Trigonarca sp.. Glycymeris staminea (Conrad) Glycymeris trigonella (Conrad) CUcullaea macrodonta Whitfield Ostrea alabamiensis Lea . Pteria limula (Conrad) Pecten wilcoxii Dall Amusium sp. Modiolus alabamensis Aldrich Periploma sp. Venericardia planicosta Lamarck Protocardia lenis Lucina papyracea Lea Lucina cf. pandata Conrad . Lucina claibornensis Conrad Cytherea var. nuttalliopsis Heilprin . Cytherea texacola Harris . Cytherea subimpressa Conrad . Psammobia ozarkana Harris . Psammobia blainvillei Lea ? . Psammobia papyria Conrad ? . Spisula parilis (Conrad) . Corbula oniscus Conrad .. Corbula alabamiensis Lea

H.l M.l G. D. S. W.

E. S.

I

T.W.V.

X X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

282

GEOLOGY OF THE COASTAL PLAIN

Dr. Vaughan states: "Of the specimens collected by Professor 1lcCallie, Mr. Sloan and myself, only CucullaJa macrodonta and Cytherea subimpressa suggest Wilcox age; however, the horizon is low in the Claiborne, probably the very base, as indicated by Turritella nasuta, Pecten wilcoxii, etc., and their overlapping with two species usually not ranging above the Wilcox."

Griswoldville.-The red sand which appears at Roberts (see sec-
tion, page 280) can be traced, covering the ridge, three miles south to
the cuts on the Central of Georgia Railway, one and a quarter mnes
west of Griswoldville. Here the red, argillaceous sands fill erosion
gullies in Cretaceous beds. About three-quarters of a mile south of
these cuts there is a notable exposure of quartzite full of casts and
silicified shells. This rock has the appearance of having been origi-
nally a calcareous sand. It lies near the base of the Claiborne and is
100 feet or more below the tops of the high ridges which are made up
of red, argillaceous sand. The quartzite is probably only a local de-
posit. The hard rock here is provisionally considered a part of the
Congaree clay member..
Prof. G. D. Harris' has made the following notes:
"About a year ago, while on our way to take charge of geological work ip. Louisiana, we collected at some fine fossiliferous localities of this horizon in the vicinity of Griswold, and heard of several others in the same general region, but had no time to inspect them. This outcrop is in a Vshaped valley about two miles south of Griswold, or about 10 miles east of Macon. The lower Claiborne rock consists of a hard bed of the typical "buhrstone'' of former geological works, about 10 feet in thickness, replete with fossil remains. In less indurated, or in sandy seams, and just below the main bed many fine specimens of silicified shells were collected. Sandy beds were noted below the above mentioned hard layer for a distance of 40 feet. Above and between this outcrop and the station, red sandy hills rise to the height of 140 feet above the fossiliferous bed or above the station, the latter two points being upon about the same level. Near the station were noted red sands mottled with white clay. One mile west of Griswold extensive white clay deposits were found along the line of the railway leading to Macon."

Prof. McCallie has collected fossils on the property of J. R. Van Buren and Company, one and one-half miles west of Griswoldville, which Dr. Vaughan has identified as follows:

Fossils from J. R. Van Buren Company's property.

"Platytrochus stokesi (Lea) Flabellum ouneiforme Lonsdale Turbinolia pharetra Lea Endopachys maclurii (Lea)
Turbinella sp. Plejona sp. Levifusus trabeatus Conrad Mesalia vetusta (Conrad) ? Calyptrea aperta (Selander)

Dentalium aff. blandum de Greg. Nucula ovula Lea Nucula magnifica Lea Crassatellites protextus (Conrad) Phacoides cariniferus (Oonrad) Protocardia sp. Corbula alahamiensis Lea Panopea sp.

'American Paleontology, Bull. No. 16, 1902.

J.1cBEAN FORMATION

283

"The species obtained at this locality are not sufficiently restricted in their stratigraphic range to decide where in the Claiborne group the exposure belongs."
BlliB COUNTY
Macon.-Both the Congaree clay member and Barnwell sand appear in gullies 10 miles southeast of Macon, near the eastern boundary of Bibb County. Prof. McCallie furnishes the following section:

Section in Macon-Marion public road, ten miles southeast of Macon.

Feet.

McBean formation, (Congaree clay member).

7. Red clays. . . . . . . . . .

5

6. Porous, cream-colored clay with fossil leaves and

bivalves . . . . . . . . . . . . . . . . . . . .

10

5. Clay filled with bivalves . . . . . . . . .

1.5

4. Same as No. 6, with no fossils, but containing sand

partings . . . . . . . . . . . .

8

3. Same as No. 6 . . . . . . . . . . . . . . . . . . . . 10

2. Fossiliferous sandstone and chert . . . . . . . . . . . 10

1. Crossbedded sands and white clays . . . . . . . . . . 30

Fossils from this locality are Nucula ovula, Diplodonta, Orassatellites protextus, and several species of fossil leaves.
Exposures of fullers earth and sand appear in large gullies on the John Tharpe estate near the public road. The following section was made at or near the same locality as the preceding section:

Section in gu!lies on Tharpe estate.

Feet.

Barnwell sand.

11. Fine, red sand . . . . . . . . . _. . . . . . .

50

McBean formation, (Congaree clay member).

10. Thick-bedded, fullers earth, partly concealed by the

"creep" of the overlying red sand . . . .

15

9. Alternating thin layers of clay and fine sand

10

8. Heavy-bedded fullers earth . . . . .

5

7. Fullers earth, sand partings . . . . .

15

6. Thick layered, jointed fullers earth .

5

5. Interval concealed . . . . . . . . 4. Thin layers of clay, sand partings . 3. Thick layers, sandy . . . . . . .

} 20

2. Concealed interval of a few feet .

?

Lower Cretaceous.

1. White clay and sand . . . .

The fullers earth contains casts of fossils, leaf impressions, and bits of lignitic wood.

ECONOMIC GEOLOGY OF MCBEAN FORMATIOl'l
The Oongaree member contains beds of fullers earth at several lJ calities between Grovetown and Ocmulgee River, which should

284

GEOLOGY OP THE COASTAL PLAIN

prove to be of considerable economic value. A bed of fullers earth is at present being mined near Pike's Peak station, Twiggs County,. by the General Reduction Company, and some development work was done several years ago on the Fiske property at Grovetown. 'lhe better quality of the fullers earth of this formation possesses excellent clarifying properties, fully equal to or superior to those of the English earth. In the tests which have been made it has not proved equal to the English earth for clarifying culinary oils, but it should prove suitable for other uses to which fullers earth is put. The McBean fullers earth occurs in enormous quantities, the beds in places reaching a thickness of as much as 50 feet.
McBean marls occur in abundance in the bluffs of Savannah and Chattahoochee rivers, and at localities in Burke, J e:fferson and Washington counties. The marls, in addition to lime, contain small amounts of phosphoric acid and potash, and on certain soils and under certain conditions should be of local value as a land fertilizer.
Lime has in the past been manufactured from a shell bed near Griffin's Landing, Savannah River, Burke County; near Sunhill, Washington County, and near Bond's Store, Bibb County. However, under present industrial conditions, lime manufacture as a permanent industry would not be profitable in this region, on account of the high price of fuel, unfavorable quarrying condition, the general softness of the rock, and the presence of a high precentage of sand and clay impurities. However, it is suggested that where lime is desired for local agricultural purposes, the limestone and marl might be advantageously used at several localities. In this case expensive kilns and equipment would be unnecessary.
The Congaree clay members of the formation contains clay Df some commercial value. Plastic clay from this member is being utilized, mixed with other clays, in the manufacture of sewerpipe and fire clay products, near Harlem, Columbia County, and at Stevens Pottery, Baldwin County.
A deposit of lignite and lignitic clay occurs three miles south of Grovetown (see page 270), and has been developed in a small way. The lignite is in thin beds, interbedded with dark colored or lignitic day; the cqmbined thickness exposed in a prospect pit is 12 feet. Although a large number of nearby exposures of.strata have been examined, no evidence of any considerable amount of lignite has been found. It is believed that the area underlain by the lignite is very small, and that it is not in sufficient quantity to be an important source of fuel, although this particular deposit may possibly have a small local value. A small amount of the lignite and lignitic clay has been mined and sold as a filler for commercial fertilizers.

BARNWELL SAND

285

BARNWELL SAND

NAME
Mr. Earle Sloan1 has used the name Barnwell "buhr sands" or Barnwell "phase" for red, ferruginous sands that immediately overlie the McBean formation, as defined in this report. The type area of the Barnwell sand is in Barnwell County, S. C., where its stratigraphic position is as stated. Sloan, who has also studied the area in Georgia adjacent to Savannah River, states that the Barnwell "phase" is represented by the <iands that overlie the fossiliferous marls of Shell Bluff. As there are sands of lower stratigraphic position but very similar in appearance to the Barnwell, Sloan, in sAveral instances, confused the lower horizon with his Barnwell. A notable instance of this confusion is seen in his referring to the Barnwell the fossiliferous sands near Hixon's bridge on Tinker's Creek." The horizon of the fossils of this e;xposure is far down in the McBean formation. However, it is evident that Sloan intended this name to apply to the red, ferruginous sands of the upper horizon and not to those of the lower. He has orally given the information that he has found Turritella carinata Lea in the Barnwell sand in Barnwell County, S. C., and he is positive in his opinion that in the type area there is similarity in stratigraphic position, and in both lithologic and faunal characters with the fossiliferous, red, ferruginous sands overlying tha McBean formation in Burke County, Ga.

DEFINITION

Stratigraphic relations.-The Barnwell sand directly overlies the McBean formation and is in contact with both the marls and the Congaree clay member of the latter formati~n. The nature of the contact separating the Barnwell sand from the McBean formation has not been satisfactorily determined. There is evidence, however, that along the northern margin of the Barnwell sand area the relation is that of uneonformity,-the unconformity being of local and not of regional extent. Farther southward the Barnwell sand seems to overlie the McBean formation conformably. The probable explanation of this discordance of relationship in different parts of the area is that after the deposition of the clays and marls of the McBean formation there w_as an uplift of the region causing the shore line of tho Claiborne sea to re?ede southward a short distance, permitting eros-

1Handbook of South Carolina, pp. 86, 90 : Department of Agriculture, Commerce and

Immigration, Columbia, S. C., 1907.



Catalogue of the Mineral Localities of South Carolina, pp. 449, 460; South Carolina

Geol. Survey, 1908.

catalogue of the Mineral Localities of South Carolina, pp. 268, 460.

286

GEOLOGY OF THE COASTAL PLAIN

ion in the emerged area, followed, after a relatively short period, by resubmergence and a renewal of deposition over the entire Claiborne area.
The Barnwell sand is overlain by the Jackson formation but at no place has the exact contact between the two been observed; for this reason the nature of the contact is imperfectly known. There is some evidence in favor of a faunal and lithologic gradation, and on the other hand, a suggestion of unconformity (see page 296).
In Burke and Screve_n counties the formation is overlapped by the Vicksburg formation, and questionably by the upper Oligocene (Chattahoochee and Alum Bluff formations). In the eastern part of the State the Altamaha (Lafayette~) formation probably originally covered a large part of it, as there are now two prominent extensions of the Altamaha (Lafayette ~) at Tennille and Waynesboro. The Barnwell sand is in places covered with a small thickness of surficial gray sand of problematic origin, and by Pleistocene terrace deposits along the rivers.
Lithologic characters.-The Barnwell sand consists largely of unconsolidated red and vari-colored sands, but there are also thin layers of sandstone, quartzite, silicified limestone or flint, and thin-layers of siliceous limonite, embedded in the sands. T4e sands, especially where weathered, have a somewhat similar appearance to the red, residual sands of the Vicksburg formation, which seem to be in contact with it in the southeastern part of Burke County, and, where fossils are absent, it is difficult to discriminate between the two.
The flint and quartzite contain casts and silieeous replacements of fossils and good collections have been obtained at several localities. The sand itself is poorly fossiliferous, containing only imperfect casts and moulds of fossils and fragments of silicified wood.

Thickness.-The maximum measured thickness of the Barnwell

sand is 105 feet, this thickness being observed on Storm Branch be-

low Cox Spring, about two miles northeast of Shell Bluff postoffice;

therefore, the formation in places reaches a maximum thickness of

over 100 feet.

Paleontologic characters.-Among the common fossils of the Barn-

well sand are: M ortonia, Mesalia vetusta (Conrad), Turritella cari-

nata Lea, Glycymeris staminea (Conrad), Crassaltellites protextus

var. lepidus Dall, Venericardia alticostata (Conrad), Cytherea per-

ovata Conrad, Spisula pra:etenuis (Conrad), etc. The best collection

of fossils from a single locality is that from Old Town, seven and

one-half miles southeast of the present site of Louisville. A list of

the species is given on page 292.



BARNWELL SAND

287

Areal distribution.-The Barnwell sand of the Claiborne group i,; practically co-incident in its distribution with that of the Claiborne group as a whole. The formation overlies both the marls and the clays of the McBean formation and extends to the Fall Line. It is present over parts of the following counties: Columbia, Richmond, Burke, McDuffie, Jefferson, Glascock, Washington, Hancock, "Wilkinson, Baldwin, Twiggs, Jones, and Bibb. No evidence was found indicating that the fossiliferous red sands in the southern part are later in age and superimposed upon the sands which near the Fall Line overlie the Congaree clay member and fullers earth. It is probable that red sands between Flint and Chattahoochee rivers belong to this formation but as yet no positive statement can be made. The sand forms the conspicious red soils of the Claiborne group and lends character to this area of the Coastal Plain.
This formation is particularly well developed in Burke County,' where it contains fossiliferous flint and appears at the surface as a dark red, ferruginous sand. It is also w~ll developed over other counties to the west.
Physiographic expression.-The Barnwell sand has been an impor tant factor in determining the character of the topography in the region of its occurrence. The greater part of the area is hilly and broken, since the friable sands and soft clays of the formation have yielded readily to erosion. In Twiggs, Wilkinson, and Washington counties, valleys have been cut 150 to 200 feet below the level of the ridges and small plateaus, and the hills are often furrowed by deep gullies and ravines. In Burke and Jefferson counties there are flat plains in which lim(;3sinks occur, due to the collapse of solution cavities in the underlying McBean formation.
Structure.-The bedding planes of the Barnwell sand have been largely obscured as the result of the chemical changes which have taken place in the materials. For this reason it has been impossible to obtain accurate dip observations. However, there is doubtless a low dip of the beds to the southward or southeastward, probably not exceeding 10 or 15 feet to the mile.
LOCAL DETAILS
BURKE COUNTY
Storm Branch and Cox Spring.-Marl containing Ostrea georgiana and belonging to the McBean formation, was found on Storm Branch below Cox Spring, and one and three-quarters to two miles northeast of Shell Bluff post-office. Typical Barnwell sand overlies the marl at this locality.
1Note by Doctor Vaughan: These sands over most of Burke County are the equivalent or approximately the equivalent of the Gosport greensand of Alabama.

288

GEOLOGY OF THE OOASTAL PLAIN

A section three-quarters of a mile below Cox Spring shows the following:

Section three-quarters of a rnile below Cox Spring.
Feet. Barnwell sand.
4. Red sand containing a few thin layers of flint . . . . . 85 McBean formation.
3. Argillaceous, sandy marl; contact with the above sand obscured. This layer contains Oaricella, Pseudoliva vetusta, Orassatellites protextus ( ?) , Oytherea. Thickness exposed . . . . . . . . . . . . . . . . . 3
2. Soft, white, sandy marl containing Ostrea georgiana . 3 1. Concealed to the swamp level . . . . . . . . . . . . 2

At Cox Spring fossils were collected from thin flint layers in red sand, which are 8 to 10 feet higher than the marl bed No. 2 of the preceding section. The fossils identified are: Platytrochus stokesi (Lea), Turritella carinata Lea, M esalia sp., Astarte sp.
The section at Mobley Bluff, one mile below the spring, IS as follows:

Section at Mobley Bluff.

Feet.

Barnwell sand.

10. Red sand . . . . . . . . . . . . . . . . . .

15+

9. Red sand containing fragmental layers of flint and

quartzite, a few indetermina,ble fossils .

4 ?

8. Red sand . . . . . . . . . . . . . . . . . .

8

7. Sand with very thin layers of drab clay . .

5

McBean formation.

6. Soft, argillaceous marl and clay; fossils Orepietula,

probably lirata, Oalyptrea aperta, Nucula, Modiolus

Orassatellites probably protextus . .

3

5. Hard marl, a few large oyster shells .

4

4. Soft, sandy marl and clay . . .

3

3. Bed of large Ostrea georgiana .

3

2. Soft, calcareous, sandy clay . .

11

1. Concealed to level of swamp . .

2

The localities are one and one-half miles southwest of the marl exposure in Cox ravine described by Dr. Vaughan, (see page 242).
The red sand with flint layers reaches a thickne;:;s of over 100 feet in this part of Burke County.
Waynesboro.-Fossiliferous flint of the Barnwell sand occurs m the railroad cut two miles north of Waynesboro. .

Section in railroad cut two miles north of Waynesboro.

Barnwell sand. 3. Red soil and limonite fragments . . . . . . .
2. Fossiliferous, sandy flint in red residual clay . 1. Argillaceous, coarse, quartz sand . . . . . . .

Feet. 3 6 7

BARNWELL SAND

289

Characteristic Claborne fossils have been identified from this locality.
At Rocky Creek churc-h, five miles west of "\Yaynesboro, there is an exposure of 15 feet of fossiliferous flint overlain by red argillaceous sand. Dr. Vaughan collected at this locality Turritella carinata (Lea), Glycymeris staminea (Conrad), Crassatellites protexus var. lepidus Dall, and Cytherea perovata Conrad.. Residual fragments or boulders of flint are common south of this locality, and were noted to a point on the :Midville road :nine miles southwest of
Waynesboro. A siliceous or sandy chert layer, five feet thick, embedded in bright
red, pebbly sand occurs on the Shell Bluff road on the west side of Briar Creek, three miles northeast of Waynesboro. Between the . five and six mile-posts on the same road, residual flint fragments containing Mortonia, Turritella, etc., appear over the surface.
Dr. Vaughan has determined Claiborne fossils from residual flint in red sand at Thompson's bridge over Briar Creek, nine milen east, and at Dr. Steiner's farm five miles southwest of Waynesboro. These exposures and the red sand at McBean belong to the Barnwell sand.

Jfiduille.-Flint rock is exposed at the Jones Mill site (also known as Burton Mill) five miles north of Midville. Ther.c is an exposure, six feet in thickness consisting of both porous and tripoli-like flint, jasper, and chalcedony. It contains poorly preserved fossils,-Turritella carinata and Crassatellites protexus have been identified. The surface north of }.'[idville is a red, residual sand covered with a thin veneer of gray sand. The J\fidville flint is .-~orrelated with that in the vicinity of \Y aynesboro.

Boyd Farm.-At a point about four and one-hal miles west o:r Hancock Landing, Sannnah River, beds of flint were found in the red sand formation, and fossils were collected from it. This locality is at a spring on the Percy Boyd farm, about three and onehalf miles southwest of Shell BJuff postoffice. The stratum lies at least 20 to 30 feet higher than the Ostrea georgiana bed, which was found on the edge of the swamp of Newberry Creek, about threequarters of a mile southwest.

List of fossils near spring on Percy Boyd's farm, three and one-half miles southeast of Shell Bluff postoffice.

Turbinolia pharetra Lea Mortonia Turritella carinata I:.ea Mesalia vetusta (Conrad) Lunatia vicksburgensis (Conrad)

Leptothyra sp. Dentalium thalloides Conrad Glycymeris Venericardia parva Lea Phacoides alveatus (Conrad)

290

GEOLOGY OF THE COASTAL PLAIN

The sand and flint at this locality are characteri~tic of the Barnwell sand.

Stony Bluff, Savannah River.-No exposures of consequence appear between Limekiln Bluff and Stony Bluff, a distanct:J of 14 miles by the river. At Ellison's Landing, there is a swamp bluff lying about 150 yards back from the river, but the exposures &re poor and only red sand and white sandstone or quartzite is exposed. There is a lithologic change in the character of the strata, the marls apparently having dipped beneath the level of the river. The rock at Stony Bluff, which is about 25 feet high, consists of ledgr-s and residual, scattered fragments of brittle, translucent, opaline flint and sandstone or quartzite embedded in coarse, red sa11d.

Section at Stony Bluff.

Age ?

Feet.

6. Gray sand covering a gradual ascent to higher land .

5. Red sand; scattered flint fragments; small amount of

quartz gravel . . . . . . . . .

30

Barnwell sand.

4. Quartzite layer . . . . . . . . . . .

1.5

3. Red sand, small quartz pebbles . . .

1

2. Sandstone, or quartzite . . . . . . . . . .

... 5

1. Red or brownish argillaceous sand, sandstone fragments

near the river level . . . . . . . . . . . . . . . . . 15 ,

Only a few poorly preserYed fossils were lloted in the flint. On

the basis of lithologic similiarity the strata h'~re are co~Telated with

the flinty Barnwell sand in the vicinity of Waynesb-Jro and else-

where. Its geographic position also suggests the likelihood of its

being the equivalent of the red sands in the upper parts of the bluffs

from Shell Bluff southward.



RiCHMOND COUNTY
Hephzibah.-Hephzibah is in a direct line, B miles southeast of
. Grovetown. The Congaree clay member of 1he ~1:rBenn formation
is here observed in contact with the white clnvs and coarse sands of "
the Lower Cretaceous. The fullers earth and clay at Grovetown are here represented by a small thickness of aluminous, shaly sandstone, containing leaf impressions and thin-layered, brittle, vitreous quartzite, which contains fossils. The overlying material is red sand and represents the Barnwell sand. An excellent exposure appears in the clay pits of the Albion Clay Company one mile west of Hephzibah.
Berzelia.-A section of a hill on Sandy Run Creek, four miles south of Berzelia, on the farm of H. J\1:erry, near his residence, shows the following:

BARNWELL SAND

291

Section on farm of H. Merry.

Feet.

Eocene.

Barnwell sand.

6. At the top, gray sand covering the surface; some small

pebbles . . . . . . . . . . . . . . . . . . . . . . . 3

4. Red, white, and purplish sands containing small pebbles

in places . . . . . . . . . . . . . . . . . . . . . . 80

McBean formation, (Congaree clay member).

3. Hard, bluish-gray claystone; massive, breaks with con-

choidal fracture, and has the appearance of being

silicified fullers earth

15

Lower Cretaceous.

2. Hard, White clay . . . . . .

10

1. Talus of clay and sand . . .

Division No. 3 represents a new aspect of the fullers earth. A similar silicified clay occupying the same stratigraphic positio11 was found a few miles to the south.

JEFFERSON COUNTY
Louisville.-The following section was made along the Clark's Mill road three and one-half miles northwest of Louisville:
Section along Clark's Mill Road.

Barnwell sand. 5. At top of hill, red sand, no pebbles . .

Feet.
25

4. Siliceous, "rotten" limestone, contains Scutella, Turri

tella, and other fossils . . .

7

3. Red quartz sand . .

. . . . . ' . . 25

2. Limestone fragments in sand which appear to have

been transported . . . . . . . . . . . . . .

1

1. Red sand . . . . . . . . . . . . . . . . . . .

15

There is an exposure of fossiliferous sandstone and quartzite at Clark's Mill, seven miles northwest of LouisviEe.

Section at Olark)s Mill.

Barnwell sand.

.

Feet.

3. Red sand, similar to that covering the upland under-

lain by the Claiborne group . . . . . . . . . . . .

2. Gray sandstone and vitreous quartzite, containing frag-

ments of shells, varies from 2 or 3 feet to . . . . . 8

1. Red sand. . . . . . . . . . . . . . . . . . . . . . . 5

Along the road from Louisville to Spread red sand at the surface is continuous, but in places is covered with a thin coat of gray sand of probable residual origin. Fragments of sandstone appear at a number of places. Northwest of Louisville evidence of lime sinks may be seen in the plain.

292

GEOLOGY OF THE COASTAL PLAIN

The :following notes and list o:f :fossils has been supplied by Dr. Vaughan:
ConsideraJble collections of fossils have been 'made at Old Town, seven and a half miles southeast of the present site of Louisville, by Prof. S. W. McCallie, Earle Sloan, and myself.

List of fossils from Old Town, seven and one-half miles southeast of Louisville.

Mortonia sp. Caricella pryuloides Conrad Turritella carinata Lea Mesalia vetusta (Conrad) Calyptrea aperta (Sol.) Glycymeris staminea (Conrad) Glycymeris idonea (Conrad) Glycymeris n. sp.

Crassatellites protextus var. lepidus
Dall Crassatellites n. sp. Venericardla alticostata Conrad Cytherea perovata Conrad Spisula praetenuis (Conrad) Corbula densata Conrad Lunulites distans Lonsdale

"The fauna is upper Claiborne. Lunulites distans i's an important fossil . for correlation purposes, as its range is from the upper Claiborne (i. e. above
the Pteropsis lapidosa zone) into the JaCkson. Therefore, when found in association with such Claiborne species as Turritella carinata, Venericardia alticostata, etc., the horizon in the Claiborne group is definitely given.
Wadley.-Flint :f~agments containing :fossils are exposed at tht) bridge of the Wadley Southern Railroad, three-quarters o:f a mile south o:f Wadley. These :fragments are overlain by 15 :feet o:f red sand, and a short distance southward the typical Altamaha (Lafayette ?) :formation appears.
Dr. Vaughan :furnishes the :following note and list:

"Professor McCallie obtained from "the Central of Georgia Railway well at Wadley, at a depth of 30 feet, the following fossils:

Fossils from well at Wadley.

Flabellum cuneiforme Lonsdale Platytrochus stokes! (Lea) Endopachys maclurii (Lea) Mesalia vetusta (Conrad) Calyptrea aperta (Sol.)
Nucula ovula Lea

Leda multilineata Conrad Cytherea perovata Conrad Venericardia alticostata (Conrad) Corbula densata Conrad Lunulites distans Lonsdale

"The geologic horizon is upper Claiborne."

In the southeastern part o:f the county, flint, both porous and compact or vitreous, containing :fossils and evidently a replacement o:f limestone, appears at a number o:f places in beds and residual :fragments. Fossils, characteristic o:f the Claiborne group, have been identified :from the flint outcrops. The beds belong to the Barnwell Eand.

293

WILKINSON COUNTY

The Claiborne group in Wilkinson County consists mainly of sands, clays, and local patches of limestone, resting unconformably upon the Lower Cretaceous. The strata reach a maximum thickness of 150 to 200 feet. The general succession of beds is as follows:

General section of the Claiborne group in Wilkinson County.

Eocene.
Barnwell sand. 3. Red and yellow, highly ferruginous sands, argilla ceous and pebbly in places, which cap the
ridges and hills (approximately) . . . . . . . McBean formation, (Congaree clay member).
2. Massive and laminated, drab and greenish clays, and local beds limestone (approximately) . . . (Unconformity)
Lower Cretaceous. 1. Thick, white, clay beds and coarse kaolinic sand .

Feet. 10100 10-75

Mclntyre.-There are a number of exposures north of Mcintyre where the Barnwell sand lies in contact with the kaolin beds of the Cretaceous, the laminated, impure, fullers-earth clays not being so extensively developed as in the vicinity of Gordon. The basal sands are usually coarse, crossbedded, and contain balls and angular chunks of the Cretaceous white clays.

Section of hill, one and one-half miles north of the 159th mile-
post of the Central of Georgia Railwwy, and one quarter of a mile east of J. R. Honeycutt's house.

Eocene.

Feet.

Barnwell sand.

6. At the top. of hill; gray structureless sand . . . . . . 6

5. Red and yellow, argillaceous sand . . . . . . . . . . 45

4. White, laminated clay with sand partings . . . . . . .. 6

3. Red and yellow, coarse, crossbeddel sand, contains large

chunks of white clay, evidently torn from the under-

lying Lower Cretaceous beds . . .

20

2. Concealed a few feet . . . . . . . .

?

Lower Cretaceous.

1. Bauxite and white and stained clay .

20+

TWIGGS COUNTY
The red and vari-colored sands which are conspicuous as cappings on the ridges in the northern part of Twiggs County, are believed to belong for the most part to the Barnwell sand.
Dry Branch clay mines.-Good exposures of the Claiborne group, showing its relations to the Cretaceous, occur at the clay mines southeast of Dry Branch.

294

GEOLOGY OF THE OOASTAL PLAIN

Section in old pit at the mines of the American Clay Company.

Eocene.

Barnwell sand.

Feet.

6. Red sand, may reach a thickness of 40 or 50 feet, thick-

ness in pit . . . . . . . . . . . .

10

McBean formation (Congaree clay member).

5. Greenish, laminated clay layer . . . .

2

4. Red quartz sand . . . . . . . . . . . .

.

.. 8

3. Layer of pisolitic clay boulders and pebbles. Clay

veined with halloysite and has the appearance of

bauxite. . . . . . . . . . . . . . . . . . . . . . . 2

2. Red and white coarse quartz sand containing dissemi-

nated clay with delicate casts of fossils .

6

Lower Cretaceous.

1. Massive bed of white and cream-colored clay . . . . . 18

Section in one of the pits of the Atlanta Mining and Olay Company.

Eocene.

.clarnwell sand.

9. Red sand, seen to the top of the ridge, 60 or 70 feet

above . . . . . . . . . . . . . .

3

McBean formation (Congaree clay member).

8. Greenish, tough, waxy clay .

4

7. Fine-grained, red sand . . .

5

6. Dark, greenish clay layer . . . . . .

1

5. Red micaceous sand . . . . . . . . .

fi

4. Yellow ochreous sand . . . . . . . .

3

3. Sand containing white clay pebbles . .

3

2. Fine, white kaolinic, crossbedded sand .

8

(Unconformity)

Lower Cretaceous.

1. White, massive clay bed and arkosic sand .

Jeffersonville.-Bright red sand is conspicuous on the higher land in the vicinity of J efiersonville and Fitzpatrick, but this sand be~ comes y_ellow and lighter colored in fresh exposures. The red sands become argillaceous in depth and are underlain in places by heavy beds of fullers earth-like clays.
The following section was made from exposures in a deep gully on the H. W. McCrary farm, two miles northeast of Jeffersonville:

Section in gully two miles northeast of Jeffersonville.

Feet. In

Barnwell sand.

13. Red sand, attains much greater thickness and is

seen on the slopes to the top of the ridge . .

10

12. Yellow quartz sand . . . . . . . . . . . . . . . 10

11. Red and yellow, tough and waxy, laminated clay

with sand partings . . . . . . . . . . . . . . 4

10. Alternating thin layers of white sand and yellow

clay. . . .

.

. 3

9. Yellow clay . . . . . . . . . . . . . . . . . . . 0 2

BARNWELL SAND

295

8. White sand . .

Feet. In.

0

4

7. Yellow clay . .

0

3

6. White sand . .

0

G

5. Greenish clay .

0

5

4. Yellow argillaceous sand . . .

2

3. Layer of sand and comminuted shells in places

consolidated into sandstone . . . . . . . . . 1

2. Yellow clay and sand . . . . . . . . . . . . . . 2 G

1. Fine-grained, laminated clay with sand partings . 4

Pro. J\1:cCallie collected fossils from this locality which were identified by Dr. Vaughan as follows: Turbinella (Psilocochlis) mccalliei, Dall, Buccinanops altile (Conrad), "Mesalia vetusta (Conrad), Cytherea discoidalis Conrad, V enericardia planicosta Lam. Corbula alabamiensis Lea.
The whole section at McCrary gully is provisionally referred to the Barnwell sand.

BIBB COUNTY

Browns Jlountain.-Pro. McCallie collected from a sandy chert at this locality, a nuniber of fossils which were identified by Dr. Vaughan as follows:

Fossils from Browns "Mountain.

Flabellum cuneiforme Lonsdale Endopacys maclurii (Lea)
Mortonia sp. Calyptraphorus velatus Conrad Turritella carinata Lea Mesalia vetusta (Conrad) Calyptrea aperta (Solander) Nucula ovula Lea Pteria sp. Pecten wahtubbeanus Dall Crassatllites protextus var. lepidus
Dan

Astarte smithvillensis Harris Venericardia alticostata (Conrad) Phacoides cariniferus (Conrad) Phacoides alveatus (Conrad) Ptrotocardia nicolleti Conrad Cytherea perovata Conrad Cytherea, 2 sp.
Psammobia sp. Panopaea porrectoides Ald. Corbula oniscus Conrad

The summit of the hill is about 180 feet above the adjacent Pleis-

tocene terrace o Ocmulgee River. The lower 110 feet consists of

gray and white crossbedded sand, and thin white clay layers of Lower

Cretaceous age. The upper 70 feet of the exposure has fossiliferous

chert and sandstone at the base, while the upper slopes are red, argillaceous sand.

Pro. McCallie gives the following notes:

Section of Brown's "Mountain, nine miles southeast of "Macon.

Barnwell sand.

4. Reddish, sandy clays . . . . . . . . .

10

3. Yellowish, white clay, fossiliferous . .

20

2. Sandy fossiliferous chert . . . . . . .

25

1. Clay resembling No. 3, but no fossils .

296

GEOLOGY OF THE COASTAL PLAIN

"The thickness of the different strata here given is only approximate there being no point at which both the upper and lower layers are exposed.''
It is believed that the strata of the Claiborne group at this locality belong to the Barnwell sand.

JACKSON FORMATION
NAME
The type locality of the Jackson formation is Jackson, Miss. From the study of a large number of fossils collected at this locality Conrad1 concluded that the strata were paleontologically peculiar and gave the name Jackson to the formation. In Alabama the formation is included in the St. Stephens limestone or "White Limestone" se:ties, which comprises the Jackson and Vicksburg formations, as they could not be lithologically differentiated and hd not been pale- ontologically studied.
Brief mention of this formation in Georgia has been made by S. W. McCallie' and Otto Veatch' including it as a part of the "Vicks~ burg-Jackson," without differentiating it from the Vicksburg.
DEFINITIO:'i
Stratigraphic 1elations.-The formation represents the uppermost Eocene exposed in Georgia, and its stratigraphic position is between the Vicksburg formation aboYe and the Claiborne group below. The line of division between the Jackson and the Claiborne has not been accurately located, and it can not be stated with certainty whether or not their deposition was continuous or interrupted. The two fori:nations are similar lithologically. According to the evidence of the fossils, beds referable to the Jackson formation occur near the mines of the Georgia Kaolin Company in Twiggs County. Its existence at this locality can be explained only on the theory of deformation by faulting or folding or by an overl&p and an erosion unconformity. Paleontologic evidence has also furnished grounds for the belief that an unconformity may exist between the two formations south of Perry in Houston County, (see pages 258-260). No unconformity, however, has thus far been observed in the field.
In Mississippi the Claiborne and Jackson groups seem to be closely related. Mr. A. F. Crider' states that "even ,,1l.ere the formations have been best studied there seems to be a gradation in both the fossils and the stratigraphy from the upper Claiborne to the
lProc. Acad. Nat. Sci., Philadelphia, Vol. 7, 1855, pp. 257-263. Smith, Jobnson, and Langdon, Report on the Geology of the Coastal Plain: Geol. :Survey of Alabama, 1894, pp. 107, 108. underground waters of Georgia: Bull. Geol. Survey of Georgia No. 15, 1908. p. 33. clay deposits of Georgia: Bull. ~ol. Survey of Georgia No. 18, 1909, p. 75. crtder, A. F., Geology and Mineral Resources of Mississippi: Bull. S. S. Geol. survey No. 283, pp. 33, 34.

OEO I, OOY OP THE OAST,!L PLAI.V OF GEOJW/.4 .

PL. 11'E XXI

r

JACKSON FORMATION

297

lower Jackson." In Alabama, the Jackson has not been described as a separate formation, and very little specific information as to its relations with the Claiborne has been published. From the description ~iven in the "Report on the geology of the Coastal Plain of Alabama published in 1894 by the Alabama Geological Survey, it is evident that the two are closely related lithologically and faunally, and in sections where both are exposed no mention is made of unconformable relations.
Where the Jackson and the Vicksburg formations have been observed in the same section in Georgia there is no evidence of an unconformity or break in the deposition of the strata.
The Jackson at Rich Hill, five miles southeast of Roberta, Crawford County, rests directly upon Lower Cretaceous strata, and marine deposits at this locality indicate that the Jackson formation originally extended much farther northward than at present and suggests that the formation may have even lapped over the crystalline rocks of the Piedmont Plain.
Lithologic characters and thickness.-The formation consists of white or cream-colored, massive-bedded limestones, thin beds of marl and calcareous, glauconitic, and sandy, laminated clays. The limestones are highly fossiliferous in places consisting almost entirely o a friable mass of Bryozoa and shells. Southward from Perry there is a considerable thickness of loose red and yellow quartz sand and clay, the stratigraphic position of which has not yet been fixed, but which may belong in part to the Jackson formation. Silicification of the limestone was noted one-hal mile north of Bonaire, and also south of Perry, Houston County.
The thickness of the Jackson formation can not be determined with accuracy, mainly on account of uncertainty as to the location of the line of division between it and the Claiborne group. The formation has a low dip southward; the width of the outcrop is only a few miles, so that the total thickness probably does not exceed 150 feet. There is an exposed thickness of about 75 feet at Rich Hill, and about the> same thickness south of Perry, not including the sands underlying the fossiliferous strata.
Paleontologic characters.-The limestones of the formation are
highly fossiliferous, but the clays and sands only sparingly so. As
in Mississippi and Louisiana, the formation in Georgia seems to mark
the upper limit of V enericardia planicosta. In places, Bryozoa
make up the greater part of the rock, this being especially true of the

,'Pages 111, 128, 381, 383.

298

GEOLOGY OF THE OOA.STAL PLAIN

occurrences at Rich Hill, Crawford County, at Ross Hill, three and a quarter miles south of Perry, and at other localities. Of the 24 species which have been determined from the Jackson formation in Georgia, but six are common to the overlying Vicksburg formation. The whale-like mammal, Zeuglodon (Basilosaurus), is a characteristic fossil of the Jackson, and some fragments of its remains have been found in Georgia. As in the Vicksburg formation, Pecten and Orbitoides, are abundant; the species Pecten perplanus, Pecten nuperus, and Orbitoides mantelli, appear in both formations. All of the fossils which have been identified from the Jackson formation are given on succeeding pages.
Areal distribution.-The area underlain by the formation, so far a~ known, is small. The largest area is in Houston, Twiggs, and Pulaski counties. There is an isolated area at Rich Hill, Crawford County, and on Chattahoochee River near Alaga, Ala., there is a probable small occurrence which is mentioned by Langdon.' On Oconee River the strata exposed at Wring Jaw Landing, Johnson County, are referred to the Jackson by Dr. Vaughan. Further detailed work may reveal occurrences east of the Oconee. Evidence of the Jackson between Flint and Chattahoochee rivers has been found at only one locality, namely, on Ichawaynochaway Creek, one and one-half miles below Cordray Mill, Calhoun County. If it is present to any considerable extent as a surface formation it has not been distinguished from the strata of the Vicksburg formation and the Claiborne group.
Physiographic expression.-The limestone member of the formation has produced a prominent scarp on the south side of Indian and Mill Creeks in Houston County. Rich Hill, in Crawforw County, is a conspicuous topographic feature due to the greater resistance to erosion of the limestone and clays of the formation than that exerted by the Cretaceous sands and clays. A few limesinks occur north of Bonaire.
Structure.-The formation has a low dip southward. Visual evidence of folding was not noted in field work. However, in order to explain the conditions (see page 260) four and one-half miles south of Perry, either a fold or fault in the strata or an erosion unconformity between the Jackson formation and the Claiborne group is necessary.
Economic geology.-The limestones of the Jackson formation, south of Perry and south of Tivola, Houston County, could be used
'Report on the Coastal Plain of Alabama : Geol. Survey of Alabama. 1S94, p. 383.

JACKSON FORMATION

29~

in the manufacture of lime or for road metal. The chief objection to the stone as a road metal is its softness; however, if used in conjunction with the flint rock, which also occurs in this part of the State, it should make a fair road-surfacing material. The bryozoan, friable limestones or marls, together with some glauconitic layers, mentioned in succeeding pages, should be of some local value as fertilizers, but up to the present they have not been so utilized.

LOCAL DETAII,S
CALHOUN COUNTY
Cordray Mill.-The Jackson formation doubtless underlies the Vicksburg formation between Flint ,and Chattahoochee rivers, but an exposure has been found at only one locality. Probable Jackson occurs in the left bank of Ichawaynochway Creek, at Bateman "Hammock," one and one-half miles below Cordray Mill, 12 miles east of Edison.

Section at Bateman "Hammock"

Jackson formation.

Feet.

3. Red sand . . . . . . . . . . . . . . . . . . .

10

2. Hard, white sandy limestone; contains a Pecten,

probably P. perplanus Bryozoa, and a large oyster . 3

McBean formation.

1. Aluminous sand and sandstone, slightly calcareous;

Ostrea divaricata . . . . . . . .

1

CRAWFORD COUNTY

Rich H ill.-One of the most interesting localities of the .Tackson

formation is at Rich Hill, five miles southeast of Roberta. The hill

rises about 150 feet above the small valley on the south side, and is a:

conspicuous topographic feature. This is an isolated exposure and

indicates that the northward extension of the formation was formerly

much greater than at present. The hill is capped by brilliant red

sand, probably referable to the Jackson formation, overlying the calca-

reous beds undoubtedly belongingto the Jackson formation; the latter

rests upon white clays and 'sands of the Lower Cretaceous. The hill

is deeply trenched by erosion gullies in which the strata are laid

bare. The following section was made from the exposures in the

gullies on the south side:



Section at Rich Hill.

Eocene

Jackson formation ?

Feet. In.

13. Brilliant red sand capping the hill and forming

"creep" on the upper slopes . . . . . . . . . 30

300

GEOLOGY OF THE COASTAL PLAIN

1Jackson formation.

Feet. In.

12. Purplish and yellow sand, containing thin clay

laminae. . . . . . . . . . . . . . . . ., . . 12

11. Greenish, laminated clay, thin lignitic partings . 4,

10. Plastic, calcareous clay with fossils . . . . . . . 0 6

9. Drab, jointed laminated clay, with sand partings 6

8. Fossiliferous nodular calcareous layer . . . . . 0 12

7. Drab, soft, laminated clay with fossils; contains

nodular, calcareous layers . . . . . .

12

6. Limestone, generally soft and friable but in

places hard and compact; in places it is a

bryozoan marl so soft that it may be scraped

up with the hands. Fossils chiefly Bryozoa,

Pecten perplanus, and Mortonia sp.; fish teeth

are also abundant in places . . . . . . . . . 20

5. Brown and yellow unconsolidated sand which in

places is replaced by limestone .

12

Lower Cretaceous.

4. White, micaceous clay; maximum.

10

3. White, crossbedded clayey sand . .

10

2. White micaceclus clay . . .. . . . .

3

1. Coarse, white sand . . . . . . . .

10

List of fossils from ,Rich Hill.

(Identified by T. W. Vaughan.)

Mortonia sp.

Lucina sp., found also five and one-

Plejona sp.

half miles south of Perry.

Calyptrea aperta ( Solander)

Panopaea sp.

Ostrea georgiana Conrad

(The Mortonia referred to above is

Pecten perplanus Morton

.also found at Castle Hayne and

Pecten (probably P. nuperus Conrad) Wilmington, N. C., .and nine miles east

young and poor specimen.

of W:aynes1:>oro, Burke Oo., Ga.)

Venericardia sp.

HOUSTON COUNTY

Bonaire.-A small exposure of limestone appears m the railroad cut one-quarter of a mile north of the station. The rock is very similar to that at the quarry south of Tivola described on a subsequent page. From this locality the following fossils' have been identified:
List of fossils from one mile north of Bonaire.

Mortonia sp. Caricella sp. Turritella sp. Pecten perplanus Morton Cytherea Basilosaurus sp., probably B. macrospondylus (Harlan)
Residual boulders of both limestone and flint cap a hill one and one-half miles north of Bonaire, near the railroad. This is probably the northern limit of the Jackson formation, for to the northward
1Bull. Geol. Survey of Georgia No. 15, p. 351.

J.AOKSON FORMATION

301

of this place there is a decided change in the character of the materials, and at Wellston there is an exposure having the characteristic appearance of the Cretaceous.

Perry.-Very good sections of the Jackson formation occur in the escarpment on the south side of Flat Creek and Mill Creek, at Ross Hill three miles south of Perry, and on the Perry Henderson road, five miles southwest of Perry. The section "of the northern slope of Ross Hill, along the publi~ road, is as follows:

Section at Ross Hill

Feet.

Qlig_ocene.

Vicksburg formation.

11. Flint fragments in red, clayey soil . . . . . . . . . . 10

Eocene.

Jackson formation.

10. Soft, fossiliferous limestone or marl . . . . . . . . . 4

9. Largely concealed, but probably an argillaceous marl

or calcareous clay . . . . .

. . . . 1.

12

8. Limestone and marl . . . . . . . . . . . . . . . . . 4

7. Laminated, fine-grained, drab clay; contains small

friable, calcite nodules . . . . . . . . . . . . . . . 15

6. Ash-colored, friable marl, made up of fragments of

Bryozoa, pectens, echinoderms, et.c. . . .

5

5. Soft, fossiliferous limestone, more compact than the

above layer . . . . . . . . . . . . . . . . . . . . 4

4. Yellow and ash-colored, fossiliferous marl . . . . . . . 6

3. Hard, compact limestone . . . . . . . . . . . . . . . . 6

2. Massive soft, fossiliferous limestone; contains charac-

teristic Jackson fossils . . . . . . . . . . . . . . . 15

1. Greenish, fine-grained, laminated clay . . . . . . . . . 10

A collection of fossils was made at this locality by Prof. McCallie and identified by Dr. Vaughan as follows:

List of Fossils from the J aclcson Formation south of Perry

Locality.-Perry-Elko public road, three and one-quarter miles southeast of Perry.

Plejona petrosa (Conrad) Fusoficula cf. Iilia (Meyer) Turritella sp.
Calyptrea aperta (Solander) Dentalium thalloides Conrad Nucula ovula Lea
Leda multilineata Conrad

Leda sp.
Glycymeris sp. Pecten perplanus Morton
Pecten cf. nuperus Conrad Venericardia cf. rotunda Lea Cytherea, 2 sp. Spisula cf. funerata Conrad

At the same locality Veatch collected the following- fnssils f,,,:n the limestone in the lower part of the hill :

Orbitoides Mortonia sp.
Protocardia nicoletti Conrad

GEOLOGY OF THE COASTAL PLAIN

Along the road between this hill and Perry only vari-colored, un~onsolidated sands appear. These sands evidently underlie the calcareous strata of the Jackson formation but their age has not been definitely ascertained. They probably belong either to the Jackson formation or to the Claiborne group.

Section five miles southwest of Perry along Perry-Henderson public road.

Oligocene.

Feet In.

Vicksburg formation.

13. Top of hill, red, argillaceous sand; character

istic appearance of the residual sand of the

Vicksburg . . . . . . . . . . . . . . . . . .

12. Re,sidual flint and "rotten" limestone; contains

fossils . . . . . . . . . . . . . . . . . . .

6

Eocene.

Jackson formation.

11. Red, sandy clay, containing quartzite nodules .

15

10. Gray, laminated, shaly clay, in the nature of

fullers earth . .

.

6

9. Glauconite layer . . . . . . . . . . . . . . . . 2

8. Black clay . . . . . . . . . . . . . . . . . . . 0

3

7. Glauconite layer . . . . . . . . . . . . . . . . 0 12

6. Gray and drab, calcareous clay; contains soft

nodules of white calcite . . . . . . . . . . . 10

5. Limestone layer, very hard . . . . . . . . . . 0 6

4. White, soft, argillaceous limestone and ash-

colored friable marl . . . . . . . . . . . . . 3

3. Strata concealed, probably limestone or calcareous

clay . . . . . . . . . . . . . . . . . . . . . 10

2. Red and greenish, stiff, plastic, sandy clay; con-

tains fossiliferous flint fragments . . . . . . 10

Age?

1. Red, unconsolidated sand to level of Mill Creek;

contains fragments of silicified wood, but

no other fossils . . . . . . . . . . . . . . . . 25

Characteristic Jackson fossils have been identified from this locality. In proceeding north from Mill Creek to Myrtle, only vari-colored sands are exposed. Stratigraphically these sands lie beneath the Jackson formation. They may belong in part to the Jackson formation, but are more probably referable to the Claiborne group and Midwav formation. From the preceding section Dr. Vaughan has identified the following fossils:

Fossils' from Perry-Henderson road, five and a quarter miles south of Perry

Flabellum cuneiforme Lonsdale Endopachys sp.
Turritella Leda multilineata Conrad

'Collection made by S. W. McCallie, Bull. 15, Geol. Surv. Ga., p. 351.

JACKSON FORMATION

303

Leda, very large species, cf. pharcida Dall, but apparently new. Lucina sp., also found in the clay bed at Rich Hill
Protocardia nicoletti Conrad Corbula, apparently wailesiana Harris

Tivola.-A good section of the formation is exposed at the old quarry on the east side of the Georgia Southern & Florida Railroad, vne and one-hal miles south of Tivola.
Section at Georgia Southern & Florida quarry

Oligocene.

Feet. In.

Vicksburg formation.

16. Flint layers and fragments in red, argillaceous

sand; strata partly concealed and actual con-

tact with lower beds not seen; flint fossili-

ferous . . . . . .

. ......... .

Eocene.

Jackson formation.

15. Greenish, laminated clay; contains calcareous

concretions and thin sandstone layers .

5

14. Argillaceous limestone . . . .

0 5

13. Drab clay . . . . . . . . . . .

2 6

12. Indurated, calcareous clay . . . .

0 6

11. Plastic, drab, laminated clay . . .

4

10. Hard, calcareous layer . . . . . .

0 3

9. Greenish or dra:b, laminated clay .

4

8. Sandstone . . . . . . . . . . . .

0 3

7. Yellow, laminated, calcareous 'clay

4

6. Hard limestone . . . . . . . . .

0

f5

5. Soft limestone, contains fossils . .

0 12

4. Hard limestone, no fossils . . . . .

0 12

3. Laminated clay . . . . . . . . . . . . . . . . 4

2. Massive bedded, white and cream colored, highly

fossilliferous limestone; contains Bryozoa pec-

tens, Orbitoides, echinoids, a rather large

oyster, and sharks' teeth; fragments of large

bones are reported to have been found .

25

1. Stratum partly concealed, but probably a calcareous clay . . . . . . . . . . . . . . . ~ . . ?

Stratum No. 16 has every appearance of the residual Vicksbnrg formation from which fossils have been identified a short distance south of this locality. The limestone is, on the whole, soft, but there is some hard rock which seems to be due to crystallization of the calcium carbonate. It is very fossiliferous, being made up entirely of organic remains; parts of the beds resemble the friable marl at Rich Hill; the section is, on the >Yhole, similar to that at Ross Hill, three and one-half miles south of Perry. The rock here has been quarried for road metal. Northward from the quarry only sand is exposed. This is a red, fine-grained quartz sand with occasional thin, impure, clay layers; no fossils could be found but this sand does not appear to be of Pleistocene age or a surficial formation, and probably belongs to the Jackson formation.

304

GEOLOGY OF THE COASTAL PLAIN

The limestone again appears in a railroad cut two miles south of Tivola. A calcareous clay, probably a part of this formation, was noted a short distance east of Kathleen.

TWIGGS COUNTY

Near Dry Branch.-Acco~ding to Dr. Vaughan the evidence of the fossils shows that .Tackson strata occur near the mines of the Georgia Kaolin Company, two miles southeast of Dry Branch. There is an exposure of 15 feet of soft, white, argillaceous marl in a small ravine one-half mile southeast of the clay-working plant, which contains Bryozoa and other fossils, and is similar lithologicallY to the marl at Rich Hill. It lies 10 to 15 feet above the white clay beds of the Cretaceous, and is overlain by 125 feet of bluish or drab, laminated, sandy clay and red sand, the clay containing thin slabs of quartzite or sandstone. In this vicinity Claiborne fossiliferous strata occur at both higher and lower levels than this marl, and the presence of Jackson beds in this position implies either a deep erosion unconformity between the two formations, or a flexure. Exposures in this vicinity, so far as they have been examined, afforded no evidence either of an unconformity, or of any faulting or folding of the beds. Further detailed field work is necessary to solve this problem of stratigraphy.

List of fossils from ravine one-half mile southeast of the mines of the Georgia Kaolin Company, identified by T. Wayland Vaughan.

Platytrochus stokesi (Lea) Mortonia
Leda multilineata Conrad Pecten perplanus Morton

Protocardia
Tellina Corbula densata Conrad Bryozoa (very numerous)

Westlake.-On the old McRae plantation at a point about three and one-half miles northeast of Westlake, is an exposure of limestone that has the lithologic appearance of the Jackson formation. The soil at this particular locality is a tough clay with a much ranker vegetation than the higher sandy land. The rock is exposed at a few places, is highly fossiliferous, and has much the appearance of the limestone south of Tivola and Perry. However, Amusium ocalanum has been found here and this fossil suggests a higher horizon.
About four and one-half miles northeast of West] ake, on the J effer sonville road, ab~mt 20 or 25 feet of calcareous, laminated clay similar to that above the limestone at Rich Hill and Tivola is exposed in a gully on the land of Mr. S. G. Kitchens. Scutella ( ?) was noted in calcareous layers in the clay. The higher land above this clay is

JACKSON FORMATION

305

eovered by a bright red, ferruginous, argillaceous sand in which there are scattered fossiliferous flint fragments having the aspect o the Vicksburg formation.
On the Macon-Cochran public road, on Shell Creek, near Westlake; Prof. McCallie collected Peden perplanus Morton; on the ,;arne road one mile east of \Vestlake, he obtained Platytrochus stokesi (Lea), and Endopachys maclurii. (Lea). These exposures probably represent the Jackson formation. On the McRae farm, three miles east of Westlake, he collected Mortonia} Pecten perplanus Morton, :;nd Amusium ocalanu1n Dall, which suggest the presence of the Vicksburg formation, since Amusium ocalanum has hitherto not been found lower than the Vicksburg.

PBLASKI COUNTY.

Hawkinsville.-The Jackson formation appears on Ocmulgee River in the lower part of Taylor's Bluff, three miles above Hawkinsville.

Section of Taylor}s Bluff three miles above Hawkinsville.

Feet.

6. Concealed by vegetation . . . . . . . . . . . . . . . . 32

5. Massive wall of soft, argillaceous limestone, no bed-

ding; few fossils . . . . . . . . . . . . . . . . . . 25

4. Fossiliferous limestone, with alternate hard and soft

layers; somewhat argillaceous . . . . . . . . .

17

3. Very hard, compact, greenish-gray clay. . . . . . . . 2

2. Greenish-gray, calcareous sandstone . . . . . . . . . . 1

1. Bluish drab, compact, sandy clay to water's edge . . . 3

The fossils collected from the lower 20 feet of the section, Flabellum cuneiforme, SphenotrochWi sp.J Endopachys maclurii (Lea), Leda nultilineata} Conrad, Venericardia planicosta} Lam, and Lunulites sp., are regarded by Dr. Vaughan as of Jackson age. Amusium ocalanum} collected 22 feet from the base of the bluff, indicates that the upper part is of Vicksburg age. No unconformity was observed betw,een the two formations.

JOHNSON COUNTY.

Kittrells.-Prof. :McCallie has furnished the following section descriptive of the strata exposed in the bluff at Wring Jaw Landing on Oconee River, two miles west of Kittrells.

Section at Wring Jaw La.nding
Jackson formation. 8. Massive, red, sandy clay . . . . . . . . . . 7. Stratified, red, sandy clay 6. Bluish, lignitic clay . . . . 5. White and yell?w sands

Feet 8 8 8
4

306

GEOLOGY OF THE COASTAL PLAIN

4. Bluish clay with fossil leaves . . . . . . 3. Hard, glauconitic limestone, fossiliferous . 2. Bluish clay with fossil shells . . . . . . 1. Soft glauconitic limestone or marl . . .

Feet 4 8
.. 2

Dr. Vaughan has identified the folluwing fossils from this locality;

List of fossils from Wring Jaw Landing

Orbitoides sp.



Flabellum cuneiforme Lonsdale

Platytrochus stokesi (Lea)

Endopachys mac!urii (Lea)

:\!Iortonia sp.

;.Jucula ovula Lea

Leda Pecten perplanus Morton Ostrea trigonalis Conrad Protocardia nicolleti Conrad Lunulites distans Lonsdale

Lithologically, the strata are similar to the Claiborne material

near Sandersville and west of Tennille. The red sand which over-

lies the marl extends about smen miles east of the river, beyond

which it becomes obscured by strata of Oligocene age and by 1he Altamaha (Lafayette ?) formation.

SAVANNAH RIVER

Johnson's Landing.-Dr. Vaughan examined an exposure of fossiliferous, silicified limestone on the South Carolina side of the river, on the north side of the upper road to the lanJing, in a field just above the margin of the river swamp. Pecten perplanus Morton and numerous Bryozoa were obsen-ed. This exposure probably be longs to the Jackson formation but the evidence is not entirely conclusive.

OLIGOCENE VICKSBURG FORMATION

NAME
This division of the Tertiary receives its name from Vicksburg, ;Miss., where it \Vas first studied and named by Conrad.' It is in part the equivalent of the St. Stephens limestone of Alabama, and includes in Florida2 the Ocala, "Peninsular," and 11arianna limestone. Vaughan' has recently stated that it is probable that the Florida elivisions should be grouped as one formation. The St. Stephens limestone of Alabama has been traced from Mississippi to Chattahoochee River; it, however, includes the Jackson, ~whereas in Georgia the Jackson has been differentiated from the Vicksburg. 'rhe possibility of subdividing the Vicksburg in Georgia into t\vo formations has been considered but the present work has not been sufficiently de-

'Prof. Acad. Nat. Sci.. Philadelphia; Vol. 3, 1846. pp. 280, 281.

2Matson, G. C., and Clapp, F. G., Preliminary report on the geology of Florida;

Florida Geol. Survey, HlOfl.

.

'Contributions to the Geologic history of the Floridian Plateau, Publication No. 133,

Carnegie Institution of Washington, 1910, p. 150.

VICKSBURG FORMATION

307

tailed to furnish either a lithologic or paleontologic basis for the consistent extension of such subdivisions across the area. That subdivisions may later be made is probable.
In the previous literature on Georgia geology this formation has been briefly described under the name "White Limestone series" by Spencer/ and under the names "Vicksburg-.Jackson" and "Vicksburg" by :McCallie,' Veatch' and others. Parts of the underlying Jackson fDrmation and of the overlying Chattahoochee formation have been included under these divisions by the authors mention~C-1.
The Vicksburg formation or group was in the earlier literature referred to the Eocene division of the Tertiary, but in most of the more recent publications on Atlantic and Gulf Coastal Plain geology it has been placed under the Oligocene. The adoption of this EuroyJean division (Oligocene) of the Tertiary in the classification of the strata of the Atlantic and Gulf Coastal Plain of the United States is due largely to the studies of Dr. W. II. Dall' of the U. S. National Museum.
DEFINITION
Stratigraphic relations.-The Vicksburg formation, which is classified as Oligocene, occupies a stratigraphic position between the Jackson and the Chattahoochee formations.
Contacts with the Jackson formation were seen in Houston and Pulaski counties where there seems to be no physical break between the two divisions.
\Vest of Flint River, the Vicksburg extends northwar~d to the Midway and Wilcox belts of outcrop, and has overlapped and largely obscured the Claiborne group and Jackson formation. Unconformable contacts with the Claiborne group, the Jackson apparently missing, were noted near Fort Gaines, Cuthbert, Shellman, Americus, and Andersonville.
Unconformable relations or erosion contacts have been observed tdween the Vicksburg formation and the overlying Chattahoochee formation, in the vicinity of Bainbridge, Decatur County, by Pumpelly and Vaughan (see under Chattahoochee formation). Northward from Decatur County, in the escarpment on tho east side of Flint River, the Chattahoochee formation is doubtfully present in natural exposures, and the Vicksburg seems to be directly overlain by
'Spencer, J. W., First Report of Progress; Geol. Survey of Georgia, 1890-1891. 2McCallie, S. W., Underground waters of Georgia; Geol. Survey of Georgia, Bull. :'-!o. 15, p. 33. 3Veatch, Otto, Clay aeposits of Georgia; Geol. Survey of Georgia, Bull. No. 18, pp. 75-76. 'For a discussion of the Oligocene see papers by Dall: Proc. U. S. Nat. Mus., Vol. 19, No. 1110, 1896, pp. 303-305. Table of North American Tertiary horizons, U. S. Geol. Survey, Eighteenth Ann. Rept., 1896-1897, part 2. Trans. Wag. Inst. Sci., Philadelphia, Vol. 3, pt. 4, 1903, pp. 1546-1549.

308

GEOLOGY OF THE COASTAL PLAIN

the Alum Bluff, but it is probable that the Chattahoochee formatio~ exists in this region and is merely concealed by weathering and by the Alum Bluff formation. Eastward in Dooly, Pulaski, Laurens, Burke, and Screven counties, and other counties along the northern margin of the formation, as the Vicksburg formation is overlapped and partially obscured by the Altamaha (Lafayette {) formation, Alum Bluff formation, and by Pleistocene deposits, its relation to the Chattahoochee formation is not known, other than that it is sr:ratigraphically lower than that formation.

Lithologic characters.-The formation is made up largely of white limestones, but also contains beds of sand and clay. The limestones have been extensively silicified and in many places do not appear at all at the surface, but are concealed by vari-colored, very coarse grained, sandy clays, which are probably residual, in which residual flint fragments are imbedded.
The limestones are generally white or cream colored, soft and earthy and very abundantly fossiliferous. Flat, disc-like Orbitoides, Bryozoa, and pectens, and their fragments form nearly the whole of the rock in places. Along Flint River the rock has a characteristic vesicular or pitted appearance due to solution. There are cave-like recesses in the bluffs producing a rough jagged appearance. Bedding planes and joint planes are almost entirely absent. At a few localities, however, the limestones are hard, white, and crystalline, and sufficiently pure for use in the manufacture of lime. The softer rocks contain varying percentages of silica and clay. The silica is generally not in the form of quartz grains, but has been introduced in solution in circulating waters replacing the limestone.
The limestones have been extensively silicified and the formation is often represented by flint fragments and large siliceous boulders; at no place does the flint appear in continuous, solid or undisturbed beds. The flint is either porous and tripoli-like, or brittle, compact and translucent, having been converted into jasper and chalcedony. The white porous flint is prominent wherever the Vicksburg is the underlying geological formation. The white or cream color is due tt the porous condition of the rock, the silica of which when examined under the microscope is seen to be in translucent grains probably in the form of chalcedony. These flint rocks are in many places as fossiliferous as the limestones, and are evidently replacements of the soft, porous limesto:r;es o:f the Vicksburg formation.
The alteration in most cases has been complete, the rock rarely showing effervescence with acids. Some o:f the flint is dense, compact, vitreous or brittle and either translucent or red, yellow or brown.

VICKSBURG FORMATION

309

This variety shows fewer traces of fossils than the porous flint, but it is probably a replacement o! the limestones; as an exception, jasper in the form of nodules in the limestones, apparently produced by the segregation of silica and not by replacement has been observed at Albany.
Large boulders of int appear along Flint River from Albany to Bainbridge and form some of the most picturesque spots along the river. The boulders are characteristically vesicular and contain spherical cavities an inch or more in diameter. These cavities appear to have been originally occupied by echinoids and often a spongy skeleton-like kernel of silica remains in place of the fossil.
The Vicksburg formation is deeply weathered, the weathered product appearing at the surface as deep red, argillaceous sands, containing scattered flint fr~oments and black and brown iron oxide accretions about the size of buckshot. "\Vhere the sands have been exposed to the atmosphere for long periods of time as in old railway and road cuts, they have become case-hardened or slightly cemented by iron oxide, and crack into polygonal figures. At a number of places the residual clays and sands present a mottled appearance not unlike that of the Altamaha (Lafayette ?) formation. The freshly exposed residue of decomposition and solution is a highly siliceous, bluish or gray, tenaceous clay.
Sand beds which probably belong to the Vicksburg formation have been reported in a number of wells. In a cut of the Central of Georgia Railway, one-hal mile east of Dawson, there are two beds of varicolored sand associated with residual flint and clay, but which themselves do not appear to be residual.
'l'hiclcness.-The thickness of the formation can not be determined from natural exposures. Estimating from well records, the thickness in the western part of the State can hardly be more than 300 feet and at many localities is much less than this amount. Along the northern margin of the formation in Clay, Randolph, Webster, and Sumter counties, the thickness is less than 100 feet. Sepncer1 estimated the -thickness at Bainbridge to be 500 feet. It is probable, however, that a part of the strata included by him in the Vicksburg formation should have been referred to the underlying Eocene. The formation also appears in Burke and Screven counties, but no data for estimating its thickness in that region are available; however, it probably does not exceed that in the western part of the State.
Paleontologic characters.-The formation is highly fossiliferous. The most abundant forms are foraminifera and bryozoans. So :abundant is one genus, Orbitoides, a flat, disc-like foraminifera, va-
1Report of Progress, Geological Survey of Georgia, 1890-1891, p. 55.

310

GEOLOGY OF THE COASTAL PLAIN

rying from one-quarter inch to two inches in diameter, that the formation has been named in older literature the "Orbitoidal lime-
stone." The fauna of the Vicksburg formation possesses certain distinctive characteristics, although some of the common Vicksburg forms such as Orbitoides and Pecten perplanus are also found in the underlying Jackson formation. One of the characteristic fossils of the formation is Amusium ocalanum. Venericardia planicosta which ranges up into the underlying Jackson form_ation has not been found in the Vicksburg formation. Common Vicksburg fossils are Orbi toides mantelli, Orbitoides papyracea, Nummulites wilcoxi, Glycymeris arctatus, Pecten poulsoni, Pect'en perplanus, Amusium ocalanum, and Cytherea sobrina.

Areal distribution.-The Vicksburg formation underlies a large area in the western part of the Coastal Plain, including parts of or all of the counties of Sumter, Lee, Terrell, \Vebster, Randolph, Clay, Early, Calhoun, Dougherty, Baker, Mitchell, Miller, and Decatur. Areas also occur in Crisp, Dooly, Houston, Pulaski, Twiggs and Laurens counties. Eastward from Oconee River the formation has been largely concealed by later formations and only small areas are known in Screven and Burke counties. With the exception of the Altamaha (Lafayette?) and Pleistocene surficial deposits, the area over which the Vicksburg is the surface formation is greater than that of any other Coastal Plain formation.

Physiographic expression.-The formation has exerted a notable effect upon the topography. The general surface areas underlain by it are more nearly level than is usual in the case of the' other older Coastal Plain formations. Underground solution has been extensive and the plains are dotted by limesinks and ponds. These ponds vary from shallow, circular depressions not more than 50 feet across, to sinks occupying several hundred acres. The region is also characterized by a scarcity of surface streams tributary to the larger streams since much of the drainage is underground by way of the sinks.
Structure.__:__The beds are almost horizontal, but dip slightly to the southward, at an angle less than that of the underlying older strata. Est{mating from the supposed base of the formation at Americus and Cuthbert, and the supposed base at Albany as determined from the record of an artersian well, the dip southward probably does not exceed eight feet per mile. No flexures or faulting were observed at any place, although detailed geologic work may reveal disturbances of this character; it is certain that the Coastal Plain has undergone oscillations subsequent to the deposition of the Vicksburg formation.

VICKSBURG FORMA~TION

311

Economic geology.-The Vicksburg formation contains at a few places beds of hard, comparatively pure limestone, suitable for limeburning. The most suitable rocks of this character noted during field work are near Armena, Lee County, and on the Jones plantation three miles west of Arlington; similar rocks, however, doubtless exist at other localities. The harder phases of the limestone are also suitable for road metal when surfaced with flint; such material has been used for this purpose with some success at Albany. The flint rock of the formation may be used locally for road metal and in concrete work J\1ost of the more important hard rock exposures of the formation are mentioned on succeeding pages.

LOCAL DETAILS
CHATTAHOOCHEE RIVER
On Chattahoochee River, the Vicksburg formation appears at Miriam Landing, Decatur County, and is described by Langdon1 as a white orbitoidallimestone, having a thickness of 200 feet.
At Saffold, Georgia, and Alaga, Ala., beds of flint containing Vicksburg fossils appear in the escarpment of the seeond Pleistocene terrace at an elevation of 50 to 75 feet above river level. Limestone occurring near the river level at the Atlantic Coast Line railroad bridge, is probably referable to the underlying Eocene, and has been previously discussed.

BETWEEN FLINT AND CHATTAHOOCHEE RIVER
:Much of the region between these rivers is a nearly flat plain in which limestone exposures are rare. The surface materials consist of red, argillaceous sands, for the most part residual, in which are embedded fragments of flint that contain the same fossils as the l]mEJstone of the formation as exposed on Flint River.
Cuthbert, Randolph County.-Residual boulders of flint are numerous over the surface >vest and southwest of Cuthbert; the rock is
in part hard and vitreous and in part soft and porous. In a cut of
the Central of Georgia Railway, one and one-half miles west of the station, fossiliferous Vicksburg flint in clay rests unconformably upon red sand which is supposed to be Claiborne (see page 266.) At one place there is a pocket of laminated, lignitic clay in the Vicksburg formation. The flint at this locality contains Orbitoides; Pecten perplanus, Cytherea sob.rina, and other Vicksburg forms.
Blakely, Early County.-Dr. Vaughan has furnished the following notes on the geological conditions at Blakely:
'~eport on the Co~stal Plain of Alabama: Geol. Survey of Alabama, 1894, p, Hfi,

312

GEOLOGY OF THE COASTAL PLAIN

"The surface is composed of red sands, underlain by Vicksburg limestone changed to chert. Orbitoides mantelli (Morton) is very abundant and an apparently undescribed species of Pecten was obtained."

Prof. S. W. McCallie1 has published the record of a deep well at Blakely.

Blakely Deep lVell, Blakely, Ga.

Feet

Red, sandy clay . . . . . . . . . . . . .

. from 1 to 10

Coarse, grayish sand . . . . . . . . . . .

10 " 20

Coarse, light-yellow sand . . . . . . . . .

20 " 30

Yellowish, cherty limestone (Vicksburg)

30 " 40

Yellowish, or grayish, s~ndstone . . . . .

.

40 " 50

Light-colored, almost white calcareous sandstone prob-

ably base of Vicksburg-Jackson ..

50 " 70

Gray sands, darker at bottom . . . . .

70 " 140

Greenish sands, with Ostrea divaricata .

140 " 160

Fine, gray sand, hard ledge at bottom .

160 " 285

Fine sand, with some clay . . . . .

285 " 290

Bluish clay . . . . . . . . . . . . . .

290 " 490

Quartz sand, with glauconite . . . . . . . . . . .

490 " 500

Hard sandstone with glauconite; two oysters ap-

. parently Gryphaea and Exogyra costata . . .

500 " 510

Grayish or bluish sands . . . . . . . . . . . . .

510 " 580

From 580 feet to the bottom of the well, limestone interstratified with clays and sands is reported. The third water-bearing stratum, which is probably upper Cretaceous, is said to consist of a coarse sand.

The flint from the Vicksburg formation in this vicinity has been used for macadamizing the streets of Blakely.

Hilton, Early County.-In a railroad cut one mile west of Hilton Station, 20 feet of white, siliceous clay of the Vicksburg is exposed, overlain unconformably by coarse, pebbly sand, probably a Pleistocene terrace deposit. The residual, siliceous clay probably originated from the decomposition of a partially silicified argillaceous limestone. It lies near the base of the formation.

Dawson, Terrell Oounty.-Interesting occurrences of the Vicksburg formation are revealed in a cut of the Central of Georgia Railway one-half mile east of the station. Soft, porous, or "rotten" flint Occurs in mottled, residual, siliceous clay, but there are layers of coarse, purplish, red, and yellow sand, and pockets of clay, which .apparently are original and not residual.

Bronwood, Terrell County.-Flint fragments of the Vicksburg formation are especially abundant in the fields, three to four miles northeast of Bronwood. These are evidently near the base of the formation.

1Bull. Geol. Survey of Georgia No. 15, pp. 105-107.

GEOLOGY OF THE COASTAL PLAI OF GL>OIWJA.

PLATE XXIJ.

A. ::IIA SES OF FLINT FRO:\! THE VICKSBURG FOR111ATI0)1. EIGHT OR NINE :\ULES ABOVE BAINBRIDGE. DECATUR COU TY.

B. EXPOS RE OF FLI T AND LIMESTONE OF THE VICKSBURG FORllfATIO ' JU 1.' AI:IOVE DE \\' IT'l' FERRY, FLINT RIVER, MITCHELL COUN1.'Y.

VICKSBURG FORMATION

313

Arlington, Calhoun County.-There i::. a notable outcrop of limestone near Arlington. The rock appears in a bluff on the edge of the swamp of Spring Creek, on the T. F. Jones plantation, three and one-half miles west of Arlington. The natural exposure shows a maximum of 20 feet, of very compact, white, crystalline limestone. The purity of the rock is exceptional and it is exceedingly hard and C)mpact, whereas the formation elsewhere is generally soft. Crystallization of the calcium carbonate has probably largely destroyed fossils, but Orbitoides, Pecten, and Bryozoa were detected, though no species were determined. The fossils and the geographic position of the outcrop seem to be sufficient evidence of its Vicksburg age.
There is a conspicuous occurrence of Vicksburg flint in a cut of the Central of Georgia Railway two miles west of Arlington. The flint is embedded in a bluish red and mottled, siliceous clay.
Colquitt, Miller County.--,-Flint in the form of large projecting boulders is exposed on Spring Creek, one-half mile West of Colquitt, and on Long Branch, two and one-half miles north of Colquitt. At each place the rock is porous and tripoli-like, a condition probably due to a partial replacement of limestone, the remainder being carried away in solution. Casts and moulds of Pecten, Orbitoides, small gastropods, and a large oyster are numerous.

Andersonville, Sumter County.-Exposures of stratigraphic interest occur on the Battle plantation, five miles southeast of Ander- , sonville, and near the ninth milepost on the lower Americus-Oglethorpe road. The following succession occurs:

Section on Battle plantation.

Oligocene.

1 Vicksburg formation.

Feet.

8. Knoll of hard, vitreous flint with Vicksburg fossils

7. Red, argillaceous sand . . . . . . . . . . . . . .

6. Thin flint layer with the fossils, Orbitoides, Pee- ( . 30
ten, etc . . . . . . . . . . . . . . . ...... J

5. Red sand . . . . . . . . . . . . . . . . . . . . .

4. Yellow, sandy, glauconitic clay . . . . . . . . . . . . 12

3. Thin layer of quartzite . . . . . .

. 2

2. Purplish sand

. . . . . . . . .

. 4

(Unconformity)

-Eocene.

Claiborne group ?

1. Fine, incoherent, quartz sand . . . . . . . . . . . . . . 10+

The base of the Vicksburg here contains a small amount of lignitic matter. The Vicksburg-Claiborne unconformity is also revealed near the seventh milepost on the Americus-Oglethorpe road.

314

GEOLOGY OF THE COASTAL PLAIN

Americus, Sumter County.-ln this vicinity flint fragments are abundant in the soil and are prominently exposed in a cut of the Seaboard Air Line Railway three miles west of Americus. Vickoburg flint also occurs smith and east of Americus. In the city of Americus, the Vicksburg formation consists of deep red argillaceous sand capping the higher land and resting unconformably on non-fossiliferous sand believed to belong to the Claiborne group. This unconformity is revealed in a cut one-quarter of a mile east of the Seaboard Air Line Railway station.
Armena, Lee County.-A fine exposure of Vicksburg limestone occurs on the plantation of J\Ir.T. F. Cocke, at Annena, 11 miles northwest of Albany. About three-quarters of a mile northeast of the station 10 feet of the rock appears in a bluff of Fowltown Creek, and about one-quarter of a mile east of this latter locality, at a cave known as the "Indian Den," there is 18 feet of limestone. The limestone is overlain by a small thickness of red, residual sand, containing scattered flint fragments. The rock at both localities is a hard, white, crystalline limestone in massive beds; it is of sufficient purity to make it a valuable stone for the manufacturing of lime. The fossils, Orbitoides, Operculina, Pecten perplanus, and Amusium ocalanum, were collected here. The rock is correlated with the Vicksburg limestone at Alba1_1y and at other points on Flint River.
Palmyra, Lee County.-A fine exposure of Vicksuurg limestone also occurs on Fowltown Creek, at DaYis's Mill near Palmyra, six miles north of Albany. The limestone is soft, contains Orbitoides, Pecten, Bryozoa, etc., and resembles that at the power plant north of Albany. A maximum of 30 feet of rock is exposed and it is overlain by dark red sand.
EXPOSURES ON AND NEAR FLINT RIVER
The most typical exposnres of the Vicksburg formation occur along Flint River. For an airline distance of about 80 miles the channel of the river is entirely cut in the Vicksburg formation.
Near Oakfield, ~Worth and Lee Counties.-Limestone is exposed at the Albany & Northern Railroad bridge over Flint River, and in the bluff on the southern side of the Great Bend of the river, one and onehalf miles above the bridge,in Lee county. The rock contains characteristic Vicksburg fossils, such as Orbitoides, Pecten, etc. A minute, curled foraminifera, Operculina, is especially abundant.
One and one-half miles above the bridge a precipitous bluff 25 to 50 feet high exposes at its base 10 or 15 feet of ~white, compact, noncrystalline limestone. The rock presents a jagged and pitted appear-

VICKSBURG FORMATION

315

ance and the river has cut cave-like recesses into it. The strata over-
lying the limestone consists of red, argillaceous sand containing flint
fragments, doubtless residual, above which is a variable thickness of
Pleistocene terrace sand. This locality was described by Spencer
as the southern limit of the Claiborne group, but paleontologic evi-
dence establishes its Vicksburg age.
The limestone probably extends up the r~ver above Oakfield to a
point a short distance above the Seaboard Air Line Railway bridge.
The rock exposed in the river bank at this latter place, and at Clegg's
siding a short distance to the eastward, resembles the Vicksburg lime-
stone. The fossils noted were Orbitoides, Pecten perplanus Morton,
and Bryozoa. The possibility, however, of its being the equivalent
of the Jackson limestone south of Perry should be considered.
Dr. Vaughan furnishes the following geologic notes on eastern
Lee County and western Worth County:
"At Philema, Ga., there is a well 163 feet deep with a flow of good water. I could not get a reliable record of the well, but apparently the water comes from the Vicksburg limestone.
"There are numerous sinkholes four miles west of Philema. The subsurface rock is a soft, porous; often reddinsh-stained limestone, sometimes silicifiPri. Orbitoides is abundant. This rock apparently belongs to the Vicksburg formation.
"Specimens of limestone were obtained from a well four and one-half miles west of Philema at a depth of about 30 feet.
"Topographically, the country from Flint River about two miles above Philema, to four miles west of Philema, is 'fiat-woods,' very level, and probably does not rise more than 50 feet above the river for several miles back. About four miles west of the river there are numerous limesinks in which are deep ponds or pools. The surface formation consists of reddish sands or reddish sandy clays in which chert is abundant. It is probable that wuch of the clay is residual. The elevation of this area is higher above the river than that of the 'flatwoods,' According to the best information obtainable, the surface sands and clays are from 30 to 50 feet thick. These are underlain by limestone, the thickness of which could not be positively ascertained. According to some informants the thickness of the limestone is about 50 feet, below which there is a sand bed. However, limestone certainly occurs to a depth of about 160 feet on James Martin's place, four or five miles southwest of Philema. When I visited this place a well was being bored and the boring had reached about 160 feet, and was at that time in limestone containing Orbitoides. This place is estimated to be 75-100 feet above Philema. A bed of sand had been penetrated, but the driller did not wish to give a detailed record.
"In going down Flint River from Philema to Albany, a distance by river of 30 to 50 miles, outcrops of limestone were seen from place to place from a few miles below Philema entirely to Albany. The rock is yellowish or whitish, often indurated on exposed surfaces, and belongs to the Vicksburg formation. About a mile below the mouth of Mill Creek is an exposure of blue sandy. clay, aparently alluvial, but very different from the usual alluvium.
"The structure is extremely simple, the beds frequently showing no perceptible dip, but occasionally showing a dip slightly greater than the fall of the river. No marked flexures were observed, but at one place there were slight undulations of the strata over a distance not exceeding 100 or 200 feet."
"Fossils were collected in Lee County as follows:

il16

GEOLOGY OF THE COASTAL PLAIN

List of fossils from Lee County.
Four miles west of Philema, Lee county, Ga. Orbitoides mantelli (Morton) Echinoid Scaphander sp. Pecten perplanus Morton
Four and one-half miles south of east of Philema, out of a well 40 feet below surface.
Pl)cten (Chlamy cf. indecisus Dall) Amusium ocalanum Dall
Thirty feet below surface:
Operculina complanata (Defrance) Operculina complanata var. granulosa Lymeriea
Albany and vicinity.-Limestone and flint of the Vicksburg formation appear at a number of localities along Flint River in the vicinity of Albany. The country to the west of Albany is covered by a red, argillaceous sand, and limestone is rarely seen, though there is abundant evidence that it is the underlying formation. The best locality for studying the limestone is at the power plant on Kinchafoonee Creek two miles north of Albany. A large amount of rock has been excavated in constructing the dam at this place, and the bluffs of the creek also present a good section.

Section on Kinchafoonee Creek two miles north of Albany.

4. Pleistocene sand, flint fragments at the base .
Vicksburg formation. 3. Limestone . . . . . . . . . 2. Nodular and discontinuous flint layer; may thickness of . . . . . . . 1. Massive limestone . . . . .

Feet . 10
. 5 reach a
. 2 . 8

The limestone here i.s, on the whole, white or cream colored, soft, some parts friable, and massive bedded. It contains flint which seems to be both a replacement of limestone and also a jasper, which may be due to the segregation of silica and not to re.placement. The 'abundance of remains of marine life is notable, the rock in places being composed almost entirely of a friable mass of Bryozoa and shells.
The following notes on the Vicksburg formation in the vicinity of Albany are furnished by Dr. Vaughan:

"At the crossing of the Albany Northern Railroad over Muckafoonee Creek there is an exposure of whitish, soft, chalky limestone stained yellow in places, containing an abundance of poorly preserved fossils.
"On the east side of Flint River opposite Albany, there is an outcrop of
white limestone which is in places silicified. Orbitoides and Pecten poulsoni

VIOKSBURG FORMATION

317

are abundant. This material seems to l::relong to the Ocala limestone

division of the Vicksburg. Tlie limestone is overlain by red sands and clays

which form the surface. '

"At the springs about 3 miles south of Albany an enormous volume of

water comes to the surface through channels in the Vicksburg limestone.

Specimens of Amusium ocalanum Dall, echinoid spines, and Bryozoa were

collected at this locality. I did 'not see any Orbitoides.

"At Rock Hill about one and onehalf miles west of Albany on the road

to Dawson (not the main road) a spring issues from the limestone. The

limestone is in places cherty with numerous Orbitoides and Pecten, apparently

poulsoni.

"About three miles west of Albany there is a rise of some 30 feet and a

change in surface soil from grayish sands to red, sandy clay.

"Thirteen miles west of Albany at Providence plantation yellow limestone

and chert occur in brownish and reddish sands. Orbitoides and Pecten were

collected.

,

"About a mile south of Providence plantation a specimen of a large

Pecten was obtained.

"The following are lists of fossils collected in the vicinity of Albany:

Fossils from Albany and vicinity.

Three miles west of Albany, Ga.

Monoporella-a species common in the VicKsburgian Oligocene, and until now found in collections from no other horizon. Determined by R. S. Bassler.

Just above bridge of Albany Northern Railway over Muckafoonee Creek,

Operculina Cidaris

Macropneutes? Amusiurri ocalanum Dall.

Western end of railroad bridge at Albany, Ga.

Orbitoides mantelli (Morton) Lyria costata (Sowerby) Orthaulax? sp. Pecten perplanus morton

Crassatellites mississippiensis (Conrad)
Venus sp.

Albany, Ga., western end of wagon bridge.

Orbitoides mantelli (Morton) Orbitoides papyracea Boubee

Nummulties wilcoxi Heilprin.

Muckafoonee Creek, Albany, Ga.

Operculina complanata (Defrance).

Prof. S. W. Mc0allie1 has published the record of a deep well at Albany which is here repeated:

Log of City Artesia~n Well, No. 2. (Albany, Ga.)

Bored by Mr. E. F. Joyce.

Log by Mr. 0. W. Tift.

Feet.

Red clay . . . . . . . . .

. from 0 to 20

Light-colored clay

20 " 23

Coarse sand (Vicksburg) .

23 " 25

Light-colored clay and coarse quartz sand .

25 " 35

Limestone, Orbitoides, at 150 feet, and from 190 to

200 feet . . .

. . . . . .

35 " 200

1Geol. Surv. Ga., Bull. 15, 1908, pp. 98, 99.

318

GEOLOGY OF THE COASTAL PLAIN

Gray limestone, Orbitoides, echinoids, Bryozoa, Tere-

bratula; some shale from 230 to 240 ft. . . . .

Gray sand with comminuted shells (Ostrea) . _ .

Some shale, coarse sand, shells and sharks' teeth at

Hard layer, Ostrea divaricata . . . . .

Ostrea divaricata at . . . . . . . . . .

Ostrea alabamiensis at . . . . . . . .

Shale or marl, water vein at . . . . .

Ostrea divaricata and alabamiensis at .

Bed of lignite at . . . . . . . . . . .

Bed of lignite at . . . . . . . . . . .

Sand . . . . . . . . . . . . . . . . .

Echinoid spines, lamna teeth, stiff blue clay .

Stiff blue clay . . . . . . . . . . . . . .

Hard gray sandstone . . . . . . . . . . . .

Oligocene and Eocene from the surface to . .

Pyrite and small oysters at . . . . . . . . .

Green sands and greenish micaceous shales .

Gray sand with black particles at . . . . . .

Water-bearing horizon, limestone, with pieces of

hard, gray sandstone between 785 and 790 . .

Hard rock. . . .

. ............ .

Clay shales, with limestone between 835 and 840 .

Limestone and shales . . . . . . . . . . . . . . .

Chiefly sand, at top a little gravel. At 880 feet

limestone or calcareous sand, also light gray

micaceous sand; at. 890 feet, grayish sand, cal-

careous fragments, hard, black pieces of pebbles

and Ostrea, water-bearing micaceous sandstone

between 920 and 930 feet . . . . . . . . . . .

Blue micaceous clay at 950 feet, thick shelled

oysters, Gryphaea, the same also at 1,080 feet;

at 1,100 feet gray sand with Ostrea and Exogyra

costata . . . . . . . . . . . . . . . . . . . .

Stiff, blue clay, micaceous sandstone, oysters . . .

Very stiff blue clay, at 1,255 feet, streaks of sand

and shells, a small flow of water; from 1,240 to

1,260 soft, shiny, blue clay . . . . . . . . . .

Marl, gray sand, sandstone lumps, shells . . . . .

Gray and black sand, sandstone lumps . . . . . .

Black irregular, waterworn pebble, with hard crys-

talline fracture; coarse and fine quartz sand,

shells, decayed wood, third water-bearing

stratum; 50 gallons per minute.

Well ends in quartz sand at . . . . . . . . .

Feet
200 to 280 280 " 285
311 318 " 320
320 340 350 363 367 400 400 " 475 470 " 475 475 " 480 485 " 488 500 520 530 " 540 600
690 " 790 790 " 800
800 " 850 850 " 890
890 " 940
940 " 1,100 1,100 " 1,200
1,200 " 1,260 1,260 " 1,270 1,270 " 1,310
1,310 " 1,315 1,320

The base of the Vicksburg formation according to this section IS probably between 200 and 280 feet, and the base of the Eocene is probably above 940 feet, since according to fossils the strata between 940 and 1,100 feet are Cretaceous. Dr. Stephenson has made a recent examination of the fossils obtained from the borings of this

'.

VIOKSBURG FORMATION

319

well and reports the Cretaceous fossils Anomia argentaria) at 890 feet, and Exogyra costata (?) at 500 feet.*
Nigger Head Bend) Mitchell County.-This locality is about onf' and one-hal miles south o Hardaway and on the east side o Flint River. The bluff at this place has a maximum height o 30 feet at low water. White limestone o the Vicksburg ormation appears at the base o the bluff.
Section at Nigger Head Bend
Feet. Pleistocene.
4. Stiff, bluish clay, which weathers yellowish or brown, variable in thickness . . . . . . . . . . . . . . . . 4
3. Yellow, gray, and brown stratified sand; has a layer of pebbles at the base . . . . . . . . . . . . . . . . . 8 (Unconformity)
Oligocene. Chattahoochee formation. 2. Drab, bluish, and purplish stiff clay, having embedded in it fossiliferous flint fragments; the whole appears to be residual . . . . . . . . . . . . . . . . . . . . . 15 Vicksburg formation. 1. White or gray pitted limestone; appears both lithologic ally and paleotologically similar to limestone at Albany. . . . . . . . . . . . . . . . . . . . . . . . 2
From paleontologic evidence Dr. Vaughan has classed stratum No. 2 as Chattahoochee.
Dewitt) Mitchell County.-Sot, gray or white marl appears near the boat landing about three-quarters o a mile northwest o Dewitt. This rock rises about three feet above low water. It contains Orbitoides and the characteristic Ocala limestone fossil, A musium ocalanum. Small fragments o bones were also noted. Flint boulders, probably resulting rom the silicification o the limestone, were ob-
served.
Newton) Balcer County.-Both limestone and flint appear in the bluffs o Flint River in the vicinity o Newton. The lithologic and paleontologic appearance o the rock is similar to that at Bainbridge. A thickness o three or our feet o limestone appears in the bed o
*NOTE.-Dr. Stephenson has, in his study of the log of this well, placed the top of the Cretaceous at 500 feet. (See page 200.) This leaves a possible thickness of only about 220 feet for the combined Eocene. Based on observations over the belts of outcrop, the thickness of the Claiborne formations has been estimated at 250300 feet on Chattahoochee River and at or near the same thickness on Flint River; that of the Wilcox formation at 150 feet; that of the Midway formation froi)J. 218 feet on the Chattahoochee to 400 feet on the Flint. The thickness of the Jackson is small, but will probably increase considerably the total for the Eocene. If the top of the Cretaceous is at 500 feet in the Albany well section, then there is a surprising decrease in the thickness of the Eocene southward from the belts of outcrop.-0. V.

320

GEOLOGY OF THE COASTAL PLAIN

Cooleewahee Creek; it is a brownish, soft, somewhat granular, and oolitic rock containing Vicksburg fossils which Dr. Vaughan identi:fies as:

Fossils from Cooleewahee Creek.

Operculina complanata Orbitoides mantelli

Nummulites wilcoxi Amusium ocalanum

Excellent exposures of flint were found at Bagg's Ferry, :five miles below Newton. The flint is fossiliferous and is evidently a silici:fication and replacement of limestone. All degrees of silici:fication were noted, from soft, white, siliceous limestone to vitreous, dense, translucent flint. The greater part of the rock is a soft, white porous flint. Huge blackened fragments appear in the channel of the river and form a picturesque scene.
At Red Bluff, seven miles above Bainbridge, a limestone similar to the rocks exposed at Bainbridge appears in the bluff 25 feet above Low water. The fossils furnish evidence that the residual flint overlying the limestone at this place belongs to the Chattahoochee formation. (See pages 325, 329.) The limestone presents an uneven upper surface due to solution and- decay, and presents protrusions in the residual sandy clay.
The following fossils were collected from the limestone and identi:fied by Dr. Vaughan:'

Fossils from Red Bluff.

Orbitoides papyracea (Boubee)

Cassidulus sp.

Orbitoides n. 'sp. (stellately marked Clypeaster sp.

form)

Pecten suwanneensis Dall

Nummulites wilcoxi Heilprin

Pecten indecisus Dall

Echinolampas sp.

Amusium ocalanum Dall"

Further references to the Vicksburg formation along Flint River will be found in the chapter on the Chattahoochee formation.

Bainbridge.-Limestone of. the Vicksburg formation is exposed in the bluff on the west side of the river at Bainbridge, between the wagon bridge and the Atlantic Coast Line Railroad bridge. The river bluff here is about 20 feet high. The section is as follows:
1The foraminifera in this list were Identified by Dr. IL M. Bagg.

VICKSBURG FORMATION

321

Section at Bainbridge.
Pleistocene ? 3. Brown sand and clay . . . . . . . (Unconformity)
Oligocene. Vicksburg formation. 2. Gray or bluish residual clay . . . . 1. Soft limestone, maximum thickness

Feet .. 8
. 2 . 10

The limestone rises 10 feet above low water. It is white or gray in color, massive, and shows no bedding. Near the water's edge it has a pitted, vesicular appearance. The rock is very soft, has a granular appearance, and is in places merely a loosely compacted mass of fora.minifera and pectens. Brown, limonitic clay occurs at the top of ~e limestone. This latter material also appears at Blue Springs and Red Bluff. Soft limestone is also exposed on the left bank of the river between the wagon bridge and the Georgia, Florida, & Alabama Railread bridge, and may be seen in the low bluffs of the river at a number of points below Bainbridge. At Blue Spring, four miles below, it is overlain by the coralline flint of the Chattahoochee formation.
The following notes on the strata at Bainbridge were supplied by Dr. Vaughan:

Section of bluff on ea.st side of Flint River, back of old factory, about two miles above Bainbridge.

Pleistocene.

Feet. In.

3. Reddish sands and reddish sandy clay mixed

with some blue clay . . .

. . . . . . 15

Oligocene.

Chattahoochee formation. 2. This stratum presents diverse characters: a. Lower end of bluff along Vicksburg contact,the material consists of whitish clay, sometimes slightly sandy, and blotched with ver-

million. In the clay are pockets of limonitic

iron ore. The clay occurs in the iron ore, on

its sides, and beneath it. In the iron carbonaceous particles were found. At the lower end

of the bluff is 10 feet or more of this clay and limonite.

b. Face of bluff proper,-impure lignite, and blackish lignitic clay, 5 feet. This is a pocket

not extending to the lower end of the bluff and is replaced by purplish and bluish clays. Bluish clays, more sandy at top, overlie the lignite and

lignitic clay . . . . . . . . . . . . . . . . . 17

6

322

GEOLOGY OF THE COASTAL PLAIN

Vicksburg formation. 1. The lowest stratum seems to be that seen at the lower end of the bluff. It is a yellowish, argillaceous limestone, sometimes hard and sometimes soft and granular, composed of the remains of various calcareous organisms which show signs of trituration. Fossils are abundant but the species are few. Amusium ocalanum Dall and a very large Orbitoides, 0. papyracea Boubee, are the commonest. This stratum has evidently suffered great loss by solution, also the upper surface is extremely irregular. The thickness at one place, at the bottom of which is limestone, is fully 15 feet. In places the limestone appears as dike-like masses, the next stratum or its derivations being plastered against the sides.
"The total height of this bluff is 37 or 38 feet. The lignitic stratum is. also seen upstream from the bluff in the river bank. In this stratum were found large pieces of lignitized wood.
"The upper surface of the Vicksburg frequently rises much above the level of the base of the next higher formation, but where contacts could be found the Vicksburg passes below it. It seems that the Vicksburg has been sub-aerially eroded. Another possible explanation is that the irregular surface is due to the underground solution of the limestone. The latter hypothesis is discarded and the former accepted because of the sudden change in the lithologic character of the next higher stratum.
"Westward from Bainbridge the limestone does not appear at the surface and the formation is represented by fragments of flint, which bear the characteristic fossils of the Vicksburg formation. Limestone, however, is encountered in wells at varying depths."
Brinson, Decatur Courdy.-Large residual masses of flint occur in the pine woods on the west side of Spring Creek. The rock contains Orbitoides papyracea, Amusium ocalanurn, etc.
BETWEEN FLINT AND OCMULGEE RIVERS
Elko, Houston County.-There is a well-known occurrence of flint in the railroad cuts one mile south of Elko. The flmt appears as
massive fragments of compact jasper, breaking with a sharp, splintery, conchoidal fracture, and also as friable, very fossiliferous
masses in r-ed clay. The locality is of stratigraphic interest, and the flint and clay may be of economic value for road metal.
At Taylors Ford, four miles south of Elko, on the Unadilla road,
fossiliferous flint fragments embedded in red and yellow clay are '
prominently exposed. A collection of Vicksburg fossils was made near this locality by S. W. :McCallie.1
OCJIIULGEE RIVER
Hawkinsville, Pulaski County.-The Vicksburg formation near Hawkinsville consists of soft, white, fossiliferous limestone, contain-

1Underground waters of Georgia: Geol. Survey of Georgia, Bull. No. 15, 1908, p. 352.

VICKSBURG FORMATION

323

ing abundant fossils, together with :fragments of :fossiliferous flint embedded in residual clay. Exposures occur in the river banks near the city, at Harrells Landing, McDonnells Landing, Ways Landing, and Taylors Bluff, three miles above Hawkinsville. The formation has a similar lithologic and paleontologic aspect to that farther west. The section at Taylors Bluff is of much stratigraphic interest, since the relation of the Vicksburg :formation to the Jackson :formation are shown. (For section see page 305.)

Fossils collected :from the lower 20 :feet are regarded by Dr. Vaughan at Jacksonian in age; at 22 feet :from the base of the bluff the characteristic Vicksburg :fossil, Amusium ocalanum, was collected. No unconformity or break in sedimentation was observed between the :formations.
OCONEE RIVER.

Dublin, Laurens County.-Gray, brown and white, both porous and vitreous, compact flint rock, appears as residual remnants at a number of localities along Oconee River. The :following :fossils were obtained :from the rocks thrown :from an excavation for a reservoir at the pumping station of the city water works:

Fossils from Dublin.

Cassidulus sp.
Scutella sp. Glycymeris arctatus (Conrad)

Pecten pouisoni Morton Pecten perplanus Morton

There are no natural exposures of the limestone of the Vicksburg formation at Dublin, although it is encountered in wells.

EXPOSURES ON AND NEAR SAVANNAH RIVER

Girard and Flint Branch, Burke County.-Flint, bearing Vicksburg :fossils, "outcrops at Buxton's Mill, two and one-quarter miles south of Girard, and on the Millhaven public road at the ford at Mill Branch, two and one-half miles a little east of south of Girard. This shows that the Claiborne has dipped beneath the cover of the younger :formations at this point. There is residual red sand over the Vicksburg :formation resembling that of the Barnwell sand, rendering the precise location of boundaries difficult or even impossible.
At Ellisons Bridge, three miles southwest of Girard, vitreous flint :forming a bluff 10 :feet high is exposed a short distance above the bridge on the west side of Briar Creek. No determinable fossils were :found and it is not possible to determine whether the rock belongs to the Claiborne group or to the Vicksburg :formation.

324

GEOLOGY OF THE COASTAL PLAIN

Fragments of flint appear along Flint Branch, one and one-half miles north of Stony Bluff, Savannah River, which contain a few imperfect prints and casts of fossils. Doctor Vaughan identified Orbitoides from this locality.
J ohnsons La.nding.-At J ohnsons Landing, Savannah River, S. C., flint rock appears near the level of the river, a short distance below the landing, and also as residual fragments in the escarpment of the second terrace. The rock is white, and porous, and is similar in appearance to much of the flint in the Vicksburg formation along Flint River. Pecten, Orbitoides, and corals were noted. This rock is included in Sloan's1 "King's Creek Phase" of the Oligocene.
Hershman Lake, Screven County.-Large fragmental blocks of flint, as much as three feet in thickness, were discovered at the western end of Hershman Lake. The rock appears similar to that at J ohnsons Landing and is doubtless of Vicksburg age. No outcrops of the formation of Vicksburg were found in the river bluffs below this point.
Millhaven, Screven County.-An exposure of flint rock, which may be the equivalent of the flint of Vicksburg age on Savannah River occurs on Briar Creek a short distance above the bridge at Millhaven, o1 Garnett. It is very poorly fossiliferous, however, and it is difficult to determine its stratigraphic position beyond question. A small echinoid, Orbitoides (?), and a few poorly preserved siliceous bivalve casts were the only fossils found.
APALACHICOLA GROUP
CHATTAHOOCHEE FORMATION
NAME
The name Chattahoochee is applied to a limestone formation intervening between tlie Vicksburg and Alum Bluff formations. ThP name was first applied by D. W. Langdon' to a group of beds lying between the Vicksburg or "Orbitoidal" limestone, on Chattahoochee River, and the upper beds at Alum Bluff, Apalachicola River, 25 miles belmv River ,Junction, Fla. The age of the beds was given as "newest Eocene" or "oldest l\Iiocene," since the Oligocene equivalence of the fauna was not at that time recognized. The Chattahoochee group as described by Langdon probably included beds which are now referred to the Alum Bluff formation, as the Pecten he mentions can scarcely be other than Pecten madisonius var. sayanus Dall, an Alum Bluff fossil.
1Catalogue of Mineral Localities of South Carolina: Geol. Survey of South Carolina, p. 464.
2Amer. Jour. Sci., 3d ser., vol. 38, 1889, p. 324.

CHATTAHOOCHEE FORMATION

325

Notes on the formation in Georgia have been published by Pumpelly,' Foerste,' Spencer; Vaughan; Harper; and McCallie." It is evident that in much of the previous literature, beds which are described in this report under Alum Bluff formation, have been induded under the name Chattahoochee "beds," "series," or "group" .as used by various writers. The name Chattahoochee, as now used, is restricted to the lower portion of the Chattahoochee group of Langdon.

DEFINITION
Stratigraphic Relations.-Pumpelly' and Vaughan' have recognized an erosion unconformity between the Chattahoochee and the underlying limestone of the Vicksburg formation in Decatur County. At Blue Springs on Flint River, four miles south of Bainbridge, both formations are present, but the co,ntact between the two is much obscured by the weathering of both the Vicksburg and the Chattahoochee.
At Red Bluff, seven miles north of Bainbridge, an exposure similar to that at Blue Springs occurs. The Chattahoochee formation appears as fragments of flint in residual, sandy clay, and the weathered limestone of the Vicksburg formation appears at the base of the bluff. There is evidence at this locality, and also at the bluff back of the Old Factory ab<;mt two miles above Bainbridge (see p. 321), of an erosion unconformity. However, at Forest Falls, eight miles northwest of Whigham, no unconformities were observed in a section the base of which, according to paleontologic evidence, is referable to the Vicksburg formation, and successively higher portions of which, on the same kind of ,evidence, belong to the Chattahoochee and Alum Bluff formations.
There was probably continuous deposition from the beginning of Chattahoochee deposition to the end of Alum Bluff deposition. No evidenc~ of" any time interval between the deposition of the two has been observed in the field. Prof. J\fcCallie,' howiever, has noted an unconformity at the old Toy phosphate pit, three and one-half miles west of Boston, but whether this is an erosion unconformity or one due to the solution. and irregular weathering of the limestone

'Amer. Jour. Sci., 3d ser., vol. 46, pp. 445-447. 2Amer. Jour. Sci., 3d ser., vol. 48, 1894, pp. 41-54. 8!Wport of Progress : Geol. Survey of Georgia, 1890-1891, op. 57-59. Science, n. s., vol. 12, 1900. pp. 873-875. 'Annals New York Acad. Sci., vol. 11. pt. 1, 1906, p. 17. Underground waters of Georgia: L.eol. Survey of Georgia Bull. No. 15, 1908, p. 32. 70p. clt., pp. 445-447. 'Op cit., pp. 873-875. "'Geol. Survey of Georgia Bull. No. 5-A, 1896, p. 62.

326

GEOLOGY OF THE COASTAL PLAIN

has not been determined. When this locality was visited the relations of the clay to the limestone were obscure because the pits had become largely filled by debris.

Lithologic Cha'!'acters.-The Chattahoochee formation is in general calcareous and varies from compact, pure, crystalline limestones to earthy and argillaceous limestones, and calcareous sands ai:td sandstones. Comp~ct gray, drab, or white, fossiliferous limestones make up the bulk of the formation. A brecciated or conglomerate structure is characteristic of some of the beds. This phenomenon was observed at nearly all localities where there were good exposures. These conglomerate beds do not seem to be confined to a particular horizon, and their origin and significance are not well understood. Both the matrix and the angular or rounded fragments are limestone. Some beds appear to be pseudo-conglomerates, and consist of fossil echinoids in a limestone matrix, the structure of the echinoids having been partially obliterated, giving the appearance of waterworn fragments. The rock is phosphatic in a number of places, containing brown or black rounded pebbles of phosphate or fragments of bones and teeth. The limestone at the base of the formation has in a number of localities been replaced by silica; while in other instances the base of the formation is represented by fragmental beds of flint, containing corals and other fossils, in a matrix of residual clay. The flint closely resembles that of the underlying Vicksburg formation and can not always be easily distinguished from it.

Thickness.-In the gorge northwest of Faceville, Decatur County, the Chattahoochee formation has a probable total thickness of 100 feet. At Forest Falls, or Limesink, in the northern part of Grady County, it has an exposed thickness of 60 or 65 feet. No very reliable data are at hand for estimating its total thickness to the eastward and northeastward, under the cover of later formations. It is not great, however, and the maximum probably does not exceed 200 or 250 feet. Examination of borings from wells at Valdosta, Waycross, and Savannah indicate such a thickness, but the probability of a part of the limestone penetrated in these wells belonging to the underlying formation must be considered.

Paleontologic Characters.-Although there is no abrupt faunal break betwem the Chattahoochee and the Vicksburg formations, and there are a number of forms common to both, their faunal differences are marked. The base of the Chattahoochee contains a rich coral fauna which, in the vicinity of Bainbridge, has been studied by

OHA.TTAHOOOHEE FORMATION

327

Doctor Vaughan.' In a coral reef our miles south o Bainbridge he estimated that there were between 25 and 30 species o corals, and correlated the beds with the Oligocene o Antigua. The characteristic Vicksburg species Amusium ocalanum does not appear in the formation; the genus Orbitoides is common to both the Vicksburg and Chattahoochee formations, but the Chattahoochee species are usually different from those of the Vicksburg. Orbitolites compla'Rata, a foraminifera, occurs in the Chattahoochee formation, but has not been found in the Vicksburg. Orthaulax pugnax, a gastropod common in the Tampa formation of Florida> has been found in two localities.
Areal Distribution.-The area over which the Chattahoochee formation appears at the surface is small, as the terrane is largely concealed by the Alum Bluff and later formations. Good exposures occur along Flint River in Decatur County; and strata belonging to the formation were noted by Langdon on Chattahoochee River, nine miles above River Junction, Fla. The formation appears at Forest Falls and other lime-sinks in the northern part o Grady County; in the vicinity of Metcalf and Thomasville, Thomas County, and in the beds and bluffs of Withlacoochee and Allapaha rivers near the Georgia-Florida line. It may be represented on Ocmulgee River near Abbeville and Hawkinsville by fragmentary beds and residual flint containing corals. Limestone, outcropping near Jacksonboro, Screven County, correlated by Dr. Vaughan with the Chattahoochee formation, has a small distribution along Briar Creek in Screven County. Limestone outcropping in a small area northwest o Millen, Jenkins County, is provisionally considered as a part <if the same formation, but the data for this classification are admittedly very meager. Since the discovery o the Chattahoochee formation near Cordele, Crisp County, it is not improbable that further investigations will reveal occurrences on the east side of Flint River between Cordele and Bainbridge."
Physiographic Expression.-In portions of Decatur, Grady,,
Thomas, Brooks, and Lowndes counties, where the Chattahoochee
. formation lies near the surface, the topography is a little more hilly

ascience, n. s.~. vol. 12, 1900, pp, 873-875. 2Amer. Jour. ;:sci., 3d ser., 1889, vol. 38, p. 324. 8NOTE.-Subsequent to the completion of the work for this report an examination was made of a limestone occurring on the C. H. Spring farm, s~ven miles northwest of Sylvester, Worth County. This rock is very similar. both lithologically and paleontologically, to the Chattahoochee formation near Cordeje and at other localities near. the Florida line, and it doubtless belongs to this division of the Oligocene.--0. V.

328

GEOLOGY OF THE COASTAL PLAIN

and rugged than in other parts of sonther~1 Georgia. Lime-sinks, lakes, and ponds, due to the underground solution and consequent caving in of the limestone of the formation are notable features of the topography.
Structure.-The formation is slightly tilted southward. The dip is believed to be very low, probably not exceeding six or eight feet per mile. The top of the formation is estimated to be about 225 feet above sea-level at Forest Falls, or Limesink, and about 200 feet above sea-level near Faceville, approximately 24 miles to the southwestward. At Red Bluff, seven miles north of Bainbridge on Flint River, Dr. Vaughan has determined the presence of the Chattahoochee by fossils, and here the base of the formation can hardly be
more than 15 or :w feet above the river, while at Blue Spring, four
miles below Bainbridge, the base is about 10 feet above river level. This indicates a very low dip. What is probably limestone 0f this formation is reached in the Savannah wells at a depth of about 250 feet; the nearest known outcrop is on Briar Creek, Screven County. This indicates a southward dip of about six feet per mile.
Local dislocations of beds, due to underground solution and consequent sinking, have been observed in Thomas and Decatm counties.
Economic. Geology.-The Chattahoochee formation contains some ]imestone bed~ sufficiently pure for use in the manufacture of lime. Tho rock in places is a ,-ery hard, non-magnesian limestone. Limekilns were formerly operated at old Jacksonboro, Screven County; on the Mitchell plantation six miles east of Thomasville; and on the old Copeland plantation, about nine miles west of Sunnyhill, Thomas County, near the Florida line. The more faYorable outcrops, unfortunately, are not cmwenient to railway lines.
The rock locally has some value as building stone for foundations, chimneys, etc., and could be used in concrete work. Both the hard and the softer, impure limestones contain, at several localities, a small percentage of phosphoric acid, ~which, together with the lime, or calcium carbonate, should make them of local Yalue as fertilizers.

LOCAL DETAILS
The stratigraphic relations and the characteristic petrologic -aspects of the Chattahoochee formation are described in the following detailed sections:
DECATUR COUNTY
Bainbridge and Vicinity.-Dr. Vaughan furnishes the following description of the geology along Flint River from Red Bluff, seven miles above, to Hales' J_,anding seven miles below Bainbridge:

GEOLOGY OF THE COASTAL PLA. n; OF GEORGIA..

PLd TI!J XX II! .

B. SINK IN CHATTAHOOCHEE LIMESTONE. SHOWING THE LIMESTONE AT EDGE OF PO D. ORIGI AT~ POND. 'HREE :\1ILE WE T OF :\lETCALF. 'l'AOi\IAS CO NTY.

CHATTAHOOCHEE FORMATION

.329

"An important exposure is revealed at Red Bluff on the west side of Flint River seven miles north of Bainbridge, as the relations between the Chattahoochee and Vicksburg formations are here exhibited.

Section, Red Bluff, Flint River, seven miles above Bainbridge.

l<~eet..

3. Reddish or yellowish sand and gravel with streaks

of white and red clay . . . . . . . . . . . . .

15

2. Bluish or whitish clay, some sand; residual masses

of chert (Chattahoochee formation) 20 feet be-

low top of the bluff. . . . . . . . . . . . . . 35 to 45

1. Limestone (Vicksburg formation) 50 feet below

top of bluff to water's edge . . . . . . . . . .

10

Pleistocene.

Detailed description of Red Bluff section:

Okefenokee formation. 4. Yelowish sands and gravel about 2 feet. 3. Sands and gravel, clay streaks, about 15 feet. In places No. 3

seems to rest on the eroded surface of No. 2. The content of considerable quantity of small gravel makes a decided difference

from No. 2.

Oligocene. Chattahoochee formation. 2. Blue clay at water's edge.
2a. Pocket of Iignitic clay containing pieces of bark and other

fragmentary plant remains, about 4 feet or perhaps more in places.

2b. Clays, succeeded by clays and sands, 42 feet. Total thickness of No. 2,-46 feet.

The basal part of No. 2 is deposited unconformably over No. 1. Several holes were dug around the limestone

to determine its relation to the clays. The general characters of No. 2 are similar to those revealed at Little Horse Shoe Bend,

(p. 330), and the Old Factory, (p. 321). The clays are bluish whitish, or purplish; they are sandy in the upper portion.

About 39 feet above the river is a mass of chert, probably
residual after solution of the other portions of the stratum. Fossils are numerous,Pecten, Glycymeris, Venericardia, Venus,

Amauropsis, Oypraea, Xenophora, etc. The molluscan fauna is the same as that of the chert at Little Horse Shoe Bend.

Orbitoides is abundant, no identifiable corals collected. Vicksburg formation.

1. The oldest rock exposed is the Vicksburgian. It is a yellowish usually soft, and often granular limestone. Fos-

sils, mostly foraminifera, are numerous. Orbitoides, several species, including 0. papyracea Boubee are abundant

and attain an enormous size, several inches in diameter. There are other foraminifera, including Nummulites, sev-
eral species of mollusks, Oypraea (casts), 2 species of

Pecten, etc. This limestone is exposed at two points, where the bluff was studied and at both it extends to the

water's edge. In the down river exposure its thickness is

13 feet. Two springs burst out of the limestone at the lower of the two exposures.

The stratigraphic relations of the formations are ;,,J.e same as at the old Factory, on Flint River, two miles above Bainbridge, (see p. 321). Masses ()f chert of the Chattahoochee formation were seen along the road to Bainbridge for a distance of several miles.

330

GEOLOGY OF THE COASTAL PLAIN

Bluff below Plant System Wharf, Bainbridge.-The section here outlined"

is similar to those at Red Blu:fr, Old Factory, Little Horse Shoe Bend an<t

Hales Landing.

'

Section at Bluff below Plant System Wharf, Bainbridge.

Pleistocene.
4. Yellowish sands Oligocene.
Chattahoochee formation.
3. Cherty limestone and chert as residual masses, some lines of chert in sand, from a few inches to about . . . . . . . . . . . . . . . . . . .
2. Clays, whitish, yellowish, or brownish, with limonitic pockets of variable thickness, depending upon irregularities of surface of the underlying limestone .................. .
Vicksburg formation. 1. Limestone, yellowish, fossiliferous; Orbitoides, two species of echinoids, etc. Upper surface
irregular from water's edge to about . . . . .

Feet. 5 to 6
3 3 to 15
15

The eroded upper surface of the Vicksburg is probably more clearlyexposed here than at any other place. Perhaps some of the ferruginouspockets may be of Vicksburg age, but of this I am not sure.
Along the western side of the road, leading up the hill to Bainbridge,. a large block of the chert was seen east of the river bridge.

Section at Cherry Shoot, three miles below Bainbridge, on west side of the

river.

Feet.

3. Whitish river sand . . .

8

2. Hard chert in boulders . .

8

1. Yellowish compact sands

6

i'his is not a good exposure. No. 2 contains many fossils but tney are siliceous casts or replacements and could not be satisfactorily cut out. Mollusks: Pecten, Tellina, Lucina, Glycymeris, vardium, l'sammobia, Venus, etc., Cypraea, Natica, Ampullinopsis, Cassius. Corals: Astrocoenia, Stylophora, Orbicella, Porites, etc. Corals are abundant, though not so numerous as at Little Horse Shoe Bend.

"Blue Spring.-This spring, also known as Russell Spring, is on the east side of Flint River, about four miles by road down the river from Bainbridge. The exposure at this locality is not so good as thoee subsequently to be described. On the surface are reddish sands; these are underlain by silicified corals of a coral reef, and silicified limestone containing molusks characterizing the Cnattahochee format-on. The base of the exposure is formed by marl and limestone of the Vicksburg formation.

"Little Horse Shoe Bend.-This locality is about four miles south of Bainbridge and about one-quarter of a mile below the mouth of the stream running from Blue or Russell Spring into Flint River. The river here makes a sharp east ,o west flexure producing an exposure at the upper or eastern end. One-half mile further down stream is another flexure, the river practically resuming its general north and south course. Along the western side of this flexure is the exposure next to be described.

Section at Little Horse Shoe Bend.

Pleistocene.

4. Red sand and some gravel, a little clay in upper

part . . . .

. . . . . . . . . . . .

Feet 8

CHATTAHOOCHEE FORMATION

331

Oligocene.

Chattahoochee formation.

Feet.

3. Cherty limestone, a fossil coral reef. MollUsks,

Cypraea, Conus, Clavella, Pecten, Glycymeris,

Venus, numerous corals, Stylophora, Astro-

coenia, Orbicella, Siderastrea, Alveopora, &c.

No Orbitoides was found. This is not a connected stratum, but occurs in large detached

masses which usually roll down the hillside;

some however, are in situ. Thickness inferred

from that of the larger masses . . . . . . . .

3

Probably basal Chattahoochee.

2. Bluish or whitish sandy clay containing large ler-

ruginous segregations of limonitic character.

Thickness . . . . . . . . . . . . . . . . . . 4 to 5

(Unexposed about six feet, but probably entirely composed

of the same material as No. 2. There is some ferruginous material also some material similar to No. 1.)

Vicksburg formation.

1. Yellowish clay and yellowish argillaceous lime-

stone, composed largely of comminuted calca-

reous organisms. Fossils moderately abundant.

Amusium oc.alanum Dall, OrbitoicZes, and several

species of echinoids, &c. . . . . . . . . . . .

Section three-quarters of a mile below Blue Spring, west side of Flint River.

(Thickness not measured but estimated.)

Recent.

4. Sandy soil and humus . . . . . . . . . . . . . 1 ft. to 18 inchel!l

Pleistocene.

Feet.

3. Reddish sands and some gravel, thickness variable 6 to 10

Oligocene.

Chattahoochee formation.

2. Cherty limestone, in remnantal masses, not a

conp.ected stratum, containing many fossils, Spon-

dylus, Pecten, Turritella, Natica, O,rbitoides, Orbi-

cella, Calamophyllia, Astrocoenia pumpellyi, &c.

1. Bluish, sometimes purplish clay. In this are large

pockets of limonitic iron ore in masses often 10

to 20 feet long and 3 to 5 feet thick. Along tne

outer surface gravels are frequently cemented

into conglomerate, but the gravel apparently was

not onginally a part of the stratum. Thickness

10

The clay surrounds the iron, being both above and below it

and on its sides. No fossils were found in it. In one place the

purplish clay contained carbonaceous particles.

Section at Hales LancZing, about seven miles below Bainbridge on Flint River.

This locality is a wood landing on the west side of the river. About 1JO yards above it is the first exposure. There are three rocky points along the

Low Bluff.

Feet.

Recent.

4. Soil and whitish sands containing a few pebbles and

pieces or flakes of chert . . . . . . . . . . .

4

"332

GEOLOGY OF THE COASTAL PLAIN

{)ligocene. Chattahoochee formation. 3. Yellowish sand and masses of chert, the Chattahoochee formation, the chert residual in the sand . . . . . . . 14 There is much gravel scattered over the surface of this layer, but apparently all of it could be derived from the chert of the quartz fillings of cavities of the rock. The residual character of the chert is plainly shown. It occurs as definite layers in places in the sand, passing by disintegration into them. Many of the cherty masses are large, weighing as much as several tons. The cpllection of fossils here was better than at Little Horse Shoe Bend, as many specimens were nicely weathered out. The fossils are silicified and in the case of the corals the internal cavities are frequently filled with crystalline quartz and some residual red clay. The corals include Paracyathus, Trochocyathus, Stylophora, Astrocoenia, Orbicella, Dendracis, Astreopora, Poritidae, and Alveopora, about 21 species. Orbitoides and echinoids are also present. Among the mollusks are Conus, Fusus, Turritella, Natica, Cerithium, Terebra, Orth,aulux, Pecten, Lucina, 1' enus, Venericardia, etc. There is some clay with sand near the base of this stratum and there are indications of ferruginous pockets. Vicksburg formation. 2. Blue clay, occasionally seen along water's edge . . . . Vicksburg formation. 1. Orbitoidal limestone of the Vicksburg formation . . . . This limestone is yellowish, brownish, or whitish, cherty in its upper portion. The fossils are very large Orbitoides, 0. papyracea Boubee is very abundant, Ostrea (apparently vicksburgensis, Pecten, etc. Its mode of occurrence is extremely perplexing, as masses of it are at higher levels than No. 2 and parts of No. 3. At one exposure it rises 15 feet above the level of the river, and seems to exist as a solid ledge beneath the water's surface.
The apparent explanation is that there was a hill of the Vicksburg formation and because of subsequent eroslon masses of limestone have rolled down and assumed the present position with reference to the other strata.
Chert of the Chattahoochee formation is exposed between the landing and the Bainbridge-Hutcheson Ferry road, and along the last-named road near the turn to go to the landing."
The following notes on the Chattahoochee formation are also
supplied by Dr. Vaughan:
Powell Lime Sink.-This is on the northern slope of a hill about eight and one-half miles east of Bainbridge, about three and one-half miles northwest of Climax, on Wm. Powell's land. The position of tne sink is indicated by a patch of oak and other hard wood trees. Its perimeter is circular, about 200 feet in diameter. The depression is funnel-shaped with steeply inclined walls. At the bottom is a deep pit with almost perpendicular walls, with a cave leading westward from its bottom. The edge of the sink is some 20 feet below the top of the hill; from the edge of the sink to the edge of the pit is between 5v and 60 feet; the pit is about 25 feet deep. The entrance to this cave is through a steeply descending passage. The bottom of the sink is composed of soft, white, chalky, fossiliferous limestone. A fair number of very poor fossils were collected within the pit. They were Natica, Pecten,

CHATTAHOOCHEE FORMATION

333'

Venus, &c., the greater number unidentifiable. The fauna appears to belong to that of the Chattahoochee formation, and the rock lithologically is similar
to the Chattahoochee. There are at least 35 feet of limestone. Above the limestone in tne sink is ~5 feet of stiff blue clay. The surface is composed of residual sant.. and clay. On the western side of the hill, along the road, at the same level as the upper edge of the pit, chert containing Chattahoochee-
fossils were observed.

Section down from hill at top of Powell lime sink.

Feet.

Age ?

5. Yellow sands . . . . . . . . . . . . . . . . . . . .

Alum Bluff formation.

4. Red clay, sHtceous nodules in streaks, blue mottled clay

below . . . . . . . . . . . . . . . . . . . . . . . . 40

3. Blue clays covered by residual clays and sands with

siliceous and cherty streaks . . .

20

2. Residual clays and sands

. .'

15

Chattahoochee formation.

1. Fossiliferous chert . . . . .

Faceville.-Sanborn Mill Creek, a small stream flowing northwest from Faceville to Flint River, has exposed about 100 feet of strata of the Chattahoochee formation. The difference in elevation between Faceville and the level of Flint River is about 200 feet, and the distance is three miles. The stream flows down the steep westward-facing declivity of the Faceville plateau and has cut a narrow gorge revealing the underlying strata. Four Tertiary formations were recognized in the complete section. The top of the plateau is covered with a thin veneer of gray and brown sand. Beneath this are 40 or 50 feet of red sands belonging to the Altamaha (Lafayette?) formation. At the base of these sands, springs emerge which are in part the source of the creek. The next lower 50 feet is largely concealed and the character of the strata is inferred from the nature of the soil and a few poor exposures; the beds probably consist of sandy, laminated clays, becoming, towards the base, calcareous or argillaceous limestones; they occupy the stratigraphic position of the Alum Bluff formation. The Chattahoochee formation is mainly hmestone, varying from hard, pure, crystalline limestone to very sandy and argillaceous limestone. In a few places are calcareous sands and bedded, calcareous clays. The upper part of the limestone contains a small percentage of phosphoric acid. There are present sniall Foraminifera, other invertebrate fossils and fragments of bones. The limestone is conglomeratic in appearance, but there is some doubt as to its being a true detrital conglomerate. Limestone beds in the lower part of the section have been quarried in a sman way and are used locall:v for building stone. Fossils are nowhere abundant in the exposure. In the banks of Flint River, near the mouth of the erefk, are large fragments of fossiliferons flint. Thi~

1334

GEOLOGY OF THE COASTAL PLAIN

rock contains large Orbitoides and other fossils, and is similar in its appearance to the :flint of the Vicksburg formation at other localities. For the last half-mile of its course the creek :flows through an alluvial plain bordering Flint River, and as there is no exposure of the older rocks the actual contact between the Chattahoochee and the Vicksburg could not be seen.

Recovery.-There are a number of sinks near the railroad one mile west of Recovery, in which brown, or gray, sandy, and argillaceous limestone of the Chattahoochee formation is exposed. This rock; is similar to that exposed in the Faceville section. In places the limestone is silicified, being replaced by opaline or chalcedonic silica of vesicular appearance. Prof. McCallie' has noted large masses of silicified corals between Faceville and Recovery.

Wylie Landing.-This locality is on Flint River, five or six mile$ above its junction with the Chattahoochee, and one and one-half miles due north of the 254th mile-post on the Atlantic Coast Line railroad. The limestone exposed here evidently occupies the same stratigraphic position as the limestone at Faceville, and at the type locality, Chattahoochee, Fla.

Section at Wylie Landing, Flint River.
3. Bright red sand capping the bluff . . . . . . . . . 2. Massive-bedded limestone, weathered . . . . . . . . 1. Greenish or bluish clay containing rock fragments .

Feet ?
40 10

The limestone is grayish or white, hard, and non-crystalline; some of it has a conglomeratic appearance similar to that at Faceville. The lower 10 feet is greenish, stiff, plastic, residual clay, in which are fragments of partially silicified limestone. This limestone contains corals, an oyster, and other fossils characteristic of the Chattahoochee formation. No trace of the Vicksburg formation was observed, and it is inferred that it has dipped beneath the river level above this point.

GRADY COUNTY

Whigham.-At Forest Falls, better known locally as Limesink, eight miles north of Whigham, nearly 100 feet of strata are exposed. This section and that at Faceville have been of great value in deciphering the stratigraphy of southwestern Georgia, and have been employed to a certain extent in field work as standards of comparison for poorer exposures at other localities. The lime-sink at this locality has a depth of DO to 100 feet below the level of the surround-
1 Geol. Survey of Georgia Bull. No. 5-A, D. u2.

OHATTAHOOOHEE FORMATION

335

ing land. Into it a srp.all stream flows over a crest, approximately 70

feet above the bottom of the sink, producing a picturesque waterfall.

This locality was described by Prof. McCallie' in 1896 but

tlie stratigraphic position of the beds was not discussed.

'

Section. at Forest Falls.

Pliocene? Altamaha (Lafayette ?) formation.
6. Red, yellow and gray sand, mottled near the sur face. The sand contains brown iron oxide concretions, and greenish, "gummy" clay at the
base . . . . . . . . . . . . . . . . . . . . . Oligocene.
Alum Bluff formation.
5. Greenish, plastic sandy clay, contains concretions of silica and fragments of bones . . . . . . .
4. Yellow or buff calcareous and fossiliferous clay. The stratum is hard, and contains veinlets and minute geodes of calcite . . . . . . . . . . .
Chattahoochee and Vicksburg formations ? (Crest of falls.) 3. Calcareous clay grading into compact argillaceous, sandy limestone . . . . . . . . . . . . . . . 2. Hard limestone having the conglomeratic appearance of some of the rock at Faceville and Wylie Landing . . . . . . . . . . . . . . .
1. Very hard crystalline limestone, massive bedded. Parts of the bed are oolitic . . . . . . . . . .

Feet.
10 to 20 10 5 27 3 35

Divisions 5 and 6 are exposed in a gully entering the sink from the north.

Section from the crest of the falls to head of the small creek flowing into the sink.

Pliocene?

Altamaha (Lafayette ?) formation.

4. Red and yellow sand containing thin laminae of

clay

. . . . . . . . . . . . . . .

(Unconformity.)

Oligocene.

Alum Bluff formation.

3. Greenish or gray sandy clay . . . . . . . . . .

2. Soft, calcareous sandstone containing few fossils

argillaceous compact sand containing nodules

of calcareous sand . . . . . . . . . . . . . .

1. Indurated buff and greenish argillaceous sand

veined with calcite and containing minute calcite

crystals and geodes; base at crest of falls . .

Feet 10 to 20 15 to 20
8 5

Fossil swere collected by the writers and submitted to Dr. Vaughan, who placed the following interpretation upon the strata:

'Phosphates and marls of Georgia: Geol. Survey of Georgia, Bull. No. 5-A, p. 55.

336

GEOLOGY OF THE COASTAL PLAIN

Fossils from Forest Falls.
Fossils from the base of the first section given. Orbitoides mantem Morton, Pecten perplanus Morton. Horizon: Vicksburg
Fossils from 20 feet above base of the same section, Orbitoides. Horizon: Chattahoochee?
Fossils from layer No. 2 in the second section given Gonipora sp. Turritella, and other gastropods, Pecten sayanus Dall. Horizon: Alum Bluff.
No erosion unconformity was observed except the one separating the Alum Bluff formation from the overlying Altamaha (Lafayette ~) formation. The dense, crystalline limestone at the base of the sections seems to pass into the calcareous clay of the Alum Bluff formation without a perceptible break in the sedimentation. Fossiliferous flint such as characterized the base of the Chattahoochee in the vicinity of Bainbridge was not observed.
Bay Sink, three miles northwest of Forest Falls, is about 40 feet deep, and both limestone and flint are exposed near the bottom of the sink. The limestone is hard crystalline and closely resembles the basal rock at Forest Falls. The flint is evidently due to a silicification of this limestone. Orbitoides Pecten, and a coral were noted. According to Dr. Vaughan, the horizon here is in the Chattahoochee formation.
There are numerous other localities in the northern part of Grady County where limestones and flint of the Chattahoochee formation are 'exposed. At Little Limesink, three and one-half miles north east of Forest Falls, 30 feet of limestone similar in lithologic appearance to the limestone at Forest Falls is overlain by greenish, sandy clays of the Alum Bluff formation.
Ocklockonee River.-A limestone, which probably belongs to the CP.attahoochee formation, was found at Bishop Bluff, 13 miles .-;outheast of Whigham, a short distance above the State line. The rock is poorly exposed and appears at only one point. It is a hard, buffcolored, argillaceous limestone veined with calcite, and having a similar lithologic appearance to some of the limestone phases at FacGville and Forest Falls. The rock outcrops in a bluff about 10 feet above the river.
THOMAS COUNTY
Original Pond and other localities._:___Original Pond is located in the southern part of Thomas County, three miles west of Metcalf. The pond is due to a limesink and covers an area of about two acres. About 25 feet of limestone is exposed at the ~western end of the pond.

GEOLOGl" OF THE COASTAL

PLATE XXfV.

B. EXPOSURE OF CHATTAHOOCHEE LIMESTONE IN BANK OF WITHLACOOCHEill RIVIllR . EW BRIDGE (OR HOR BRIDGE ) THREE MILES BELOW THE VALDOSTA SOUTHERN RAILROAD BRIDGE. LOWNDE 0 >ITY.

CHATTAHOOCHEE FORMATION

337

The lower 10 feet of the limestone is hard, brittle, brecciated, and vesicular, presenting a rough, jagged surface. The breccia consists of angular fragments of hard, dense, homogeneous limestone ir a matrix of dull gray, porous limestone. There is a distinct difference between the color and texture of the angular fragments and the matrix, but both are comparatively pure calcium-carbonate. The breccia fragments are cream-colored or white, exceedingly fine-grained, homo-genous, and break with a sharp, angular, conchoidal fracture; they have much the same texture as lithographic limestone. The probable explanation of the breccia is that as the rock consisted of alternate bands of dense, fine-grained limestone and more porous, earthy limestone, the sinking of the rock consequent from underground solution caused fracturing and resulted in the brecciated condition. There is no evidence that the fragments have been transported. Incipient silication of the fine-grained limestone has taken place and specimens representing moss agate in the process of formation were obtained .
. The upper 15 feet of the exposure is dull-white, chalky limestone, less indurated than the lower rock. Foraminifera and other fossils are abundant. The slope of the hill above the limestone is strewn with fragments of phosphatic sandstone, probably weathered from the sandy clays of the Alum Bluff formation. The highest hills in this vicinity are 80 to 90 feet above the level of the pond.
The fossils observed were: numerous small Orbitoides) small gastropods, Area,) Glycymeris) Pecten) a small oyster, and corals. A large silicified coral, Siderastrea, not in place, was found. Dr. Vaughan identified from this locality: Orbicella cavernosa (Linn), and Orthaulax pugnax Heilprin.
Limestone similar to that at Original Pond occurs on the Mcintyre plantation, five miles west of Metcalf, and lllj2 miles south of Thomasville on the Thomasville-Tallahassee road. An exposure of 15 feet may be seen. This is hard, fine-grained, and brittle at the base, becoming soft and chalky at the top of the exposure. The soil above the limestone is red, sandy clay, strewn with fragments of siliceous concretions and fragments of phosphatic sandstones. Lying above the limestone there are about 4-0 feet of strata that belong to Alum Bluff formation. Greenish clay and brown sand, probably representing the base of the Alum Bluff formation were observed directly above the limestone in a gully along the public road. Specimens of Ostrea mauricensis occur in this clay.
Another exposure of'the limestone of the Chattahoochee formation occurs at the old Copeland plantation, nine miles west of Metcalf, near the State line. Two or three feet of the rock is exposed at the

338

GEOLOGY OF THE COASTAL PLAIN

site of an old limekiln. It appears in every way similar to the limestone at Mcintyre plantation and at Original Pond. The limestone occurs at the base of a hill, while on the slope above it there are fragments of flint and phosphatic sandstone.
Boston.-Limestone was observed at the abandoned phosphate pits three miles west of Boston, and at the Mitchell plantation six miles west of Boston. The character of the fossils, the lithologic appearance, geographic location, and stratigraphic relations, indicate that it probably belongs to the Chattahoochee formation.
At the old Toy phosphate pit three miles west of Boston, there are, at the base of the hill, poor exposures of limestone overlain by 30 or 40 feet of clay and sands, and some thin, interbedded, sandstone layers. The base of the hill is strewn with fragments of white flint, of hard, white to cream-colored, limestone, and phosphatic nodules. The limestone has been largely silicified. A small Orbitoides (Chattahoochee species), a Pecten, and other fossils suggesting the Chattahoochee formation were observed. An oyster, which is probably Ostrea maruricensis, occurs in the overlying greenish, sandy clays. The overlying material is regarded as the equivalent of the Alum Bluff formation.
The limestone at this locality was studied in 1890 by Spencer' and was referred to "Middle Miocene.' The locality was subsequently visited by McCallie and upon the basis of "numerous orbitolites" the rock was considered as probably the equivalent of the "White Limestone" of the upper Eocene (Vicksburg).
Limestone is exposed in a sink one-half mile north of the ,public . road on the Mitchell plantation, six miles west of Boston. Onl] five or six feet of the limestone is exposed; it is a grayish or brownish compact limestone and in places has a conglomeratic appearance. ]twas formerly used in the manufacture of lime. Some of the partially burned limestone, when rubbed or struck with the hammer, gives off a pungent odor similar to that of hydrogen sulphide. On the whol'e the rock is similar to that exposed on the Mcintyre plantation south of Thomasville. The fossils observed were Orbitoides, a Pecten, and poor specimens of gastropods and pelecypods. The overlying strata are not exposed.
There is a second sink about onP-quarter of a mile south of thP .road but no natural exposures of limestone occur. There are a few large boulders of quartzitic, slightly phosphatic clay breccia or conglomerate. These probably belong to the Alum Bluff formatior which directly ovPrlies the limestone.
--'First Report of Progress: Geol. Survey of Georgia. 1890-1891, p. 82. 2Bull. GeoL Survey of Georgia No. 5-A, 1896, p. 60.

CHATTAHOOCHEE FORMATION

339

OTHER LOCALITIES.
Withlacoochee River.-What is probably the northern-most exposure of the Chattahoochee formation on this river appears a~ Stony Lake, five and one-half miles southeast of Quitman. Limestone is exposed for about one-half mile along the west bank of the river and rises four or five feet above low water.

Section of the Bluff at Stony Lake.
Pleistocene. 3. Gray and brown incoherent sand . . . . . .
Oligocene. Alum Bluff formation. 2. Drab and white, semi-indurated fullers earth Chatt::thoochee formation. 1. Limestone and marl . . . . . . . . . . . .

Feet . 20
. 14 . 4

The limestone is white or gray,-in places yellowish, argillaceous, very hard, non-cry5talline, and in places bears numerous fossils. The bed of the river is strewn with fossiliferous chalcedony fragments that represent a silicification of the limestone. At one point along the bluff soft, marly clay and sand, one or two feet thick, containing Pecten, an echinoid, Orbitoides, and pieces of bones were observed. This soft layer seems to mark a transition from the limer,tone to the fullers earth. No evidence of an unconformity between the Alum Bluff and Chattahooohee formations was observed.
Impure, very sandy, and argillaceous limestones are found along Withlacoochee River above Stony Lake, but are regarded as phases of the Alum Bluff rather than of the Chattahoochee formation. Near Olympia, a short distance north of the Georgia-Florida State line, limestones typical of the Chattahoochee formation, appear in th: bluffs and channels of the river.

Sections on Withlacoochee River at New Bridge three miles below the
Valdosta-Southern Railway bridge.
Feet Pleistocene.
4. Yellow, sandy clay . . . . . . . . . . . . . . . . . . . 5 Oligocene.
Chattahoochee formation. 3. Layer of silicified coral, some specimens as much as a foot in diameter . . . . . . . . . . . . . . . . . . . . . . . 1 2. Soft, white, or cream colored limestone . . . . . . . . . 7 1. White, compact, pure limestone containing Orbitoides and other fossils . . . . . . . . . . . . . . . . . . . . . . 8
The limestone is prominent on both sides of the river and may be: seen at considerable depths beneath water-level. From this locality

340

GEOLOGY OF THE COASTAL PLAIN

Urbitoides complanata, Cyphastrea, Orbicella cavernosa, and Siderastrea, have been identified by Dr. Vaughan. Near Olympia, a foot or two of white, compact limestone, apparently residual, may be seen at low water, overlain by a bluish sandy clay containing chalcedonic corals.

Allapaha River.-Limestone of the Chattahoochee formation was not observed above Statenville. A short distance below Statenville the limestone rises to 10 or 12 feet above the river. The Chattahou chee formation below Statenville consists of sandy and argillaceous compact limestone and some phosphatic conglomerate or phosphat':\ pebbles in a calcareous matrix. It is overlain by unconsolidated, phosphatic sand and greenish, sandy clay. The formation is poorly fossiliferous, an echinoid being the only identifiable fossil except fragments of bones and sharks teeth.

Rock House, Crisp Oounty.-This locality is five miles southeast of Cordele, and probably is an isolated occurrence of limestone of the Chattahoochee formation. The locality was called to our !l.ttention through a reference to it by Dr. R. M. Harper.'
The appearance of the limestone here is due to a sink as it is elsewhere concealed by the Alum Bluff and Altamaha formations. The section follows:

Section five miles southeast of Cordele.

Feet

Pliocene?

Altamaha (Lafayette ?) formation.

5. A thickness of 30 or 40 feet, not well exposed; red sandy,

and mottled clay containing a few quartz pebbles, ap-

pears in places . . . . . . . . . . . . . . . . . . . . . . . 40

Oligocene.

Alum Bluff formation ?

4. Massive, weathered, greenish and drab clay . .

11

3. White, sandy clay,partly silicified and indurated

6

2. Grayish, very sandy clay . . . . . . . . . . .

10

Chattahoochee formation.

1. Massive, argillaceous limestone; contains Orbitoides com

planata, the common Chattahoochee .species, Pecten,

and small gastropods. The clay and the limestone are

not sharply separated . . . . . . . . . . . . . . . . . . . 12

Ocmulgee River.-It is not improbable that the Chattahoochee formation is represented near Hawkinsville and Abbeville. In 8 bluff, one-half mile below Hawkinsville, Dr. Vaughan has iden tified Alveopora and Amauropsis, and suggests that the Chattahoochee formation is present. A coral was found in flint at Poor Robin Spring near Abbeville.

'Phytogeographical sketch of the Altamaha grit region of Georgia: Annals New York Acad. Sci., Nov. 1906, p. 17.

CHATTAHOOCHEE FORMATION

341

1vlillen, Jenkins County.-There is a small area underlain by limestone north of :Millen. X atural exposures of the rock are rare, but its pre,-,ence near the surface is indicated by the flat topography and occasional limesinks.
At :Magnoli~ Spring, six miles north of Millen, a soft, yellow, marly limestone is exposed. An exposure, three feet thick, also oc curs at a mill one mile south of the spring. The only fossils are bryozoans and a small, ribbed Pecten which has not been specificially identified.
On the Alexander Murphy place, nine miles northwest of :Millen, limestone has been thrown from a well. The rock is white, finegrained, sandy and rather hard. It contains a small Pecten and other poorly preserved fossils.
'The age of the rocks exposed at the three preceding localities is in doubt. There are only a few exposures and the materials are poorly fossiliferous. Lithologically, the materials are unlike those of either the Claiborne group or Vicksburg formation, although from their geographic positions they might be referred to either of these. They are overlain by clays resembling those of the Altamaha and Alum Bluff formations. The rocks bear some lithologic resemblance to the limestones of the Chattahoochee formation, to which they are tentatively referred.
Jacksonboro, Screven Oounty.-An exposure of limestone occurs on Briar Creek near the site of old Jacksonboro, about eight miles I!ortheast of Sylvania, Screven County. This is one of th~ classic geologic localities of Georgia, yet only one natnral exposure of the limestone bas been found, and its distribution as a surface :fonnation is insignificant. Sir Charles Lyell, who visited the locality in 1842, re~arded the ,-,trata as of Eocene age. Dr. W. B. Clark1 studied the fauna and expi'essed the opinion that it was probably N eocene in age. Dr. W. H. Dan: also discussed the age of the formation and expressed an opinion in favor of an early :Miocene age. Dr. T. Wayland Vaughan in 1902 made a careful study of Lyell's locality, collected a number of fossils, and prepared a list of them which clearly showed their Oligocene age. Dr. Dall incorporated Dr. Vaughan's results in his "Tertiary fauna o:f Florida,'' stating:
"The locality was again visited by Doctor Vaughan in 1902 and more material obtained, leaving no reasonable doubt that the Jacksonboro horizon is practically that of the Tampa limestone or Orbitolites bed of Florida."
The following are the fossils identified by Dr. Vaughan from the Jacksonboro locality:

tBull. Bull.

U. U.

sS..

Geol. Geol.

Survey Survey

No. No.

83, 84,

p. p.

55. 88.

Trans. Wagner Free Inst. Sci., vol. 8, pt. 6, 1908, p. 1573.

342

GEOLOGY OF THE COASTAL PLAIN

Fossils from Jacksonboro, Screven County.

Orbitoides, small fiattish species. Cerithium n. sp. (Also Wakulla, Fla.,

Actaeonina ? n. sp.

Tampa horizon.)

Bulla petrosa Conrad. Also Tampa. Modulus turbinatus Heilprin. Also

Bulla 3 other species.

Tampa.

Pleurotoma servata Conrad. The va- Acmaea n. sp.



riety found at Chipola.

Turritella tampae Dall var. (Also

Pleurotoma ? sp.

Tampa.)

Drillia sp.

Strombus albirupianaG Dall.

Olivella ? sp.

Calyptraea aperta (Sol.)

Marginella sp. Large species, 4 Xenophora humilis Conrad.

columella folds.

Ampullina streptostoma Heilprin.

Mitra probably new.

Types from Tampa.

Pyrazisinus cornutus Hpn ? Also Amauropsis ocalana Dall. Also from

Tampa.

Ocala limestone and Chipola.

Pyrazisinus 2 other species, probably Fissuridea sp.

new.

Dentalium miosissippiense Conrad.

Cerithium georgianum Lyell and Pecten sp. Apparently new.

Sowerby.

Mytilus n. sp.

Cerithium playtynema Dail. (Also Chamalyelli. Dall.

Tampa.)

ALUM BLUFF FORMATION

NAME

The name Alum Bluff is applied to all the s"trata lying between

the top of the Chattahoochee formation and the base of the Miocene.

These strata are the equivalent of the Alum Bluff formation of

Florida, as recently defined, and as the formation is physically con-

tinuous from Florida into Georgia the use of the term is naturally

extended to Georgia.

'

The formation was' first studied on Apalachicola River at Alun

Bluff, 25 miles below River Junction, Fla. The section at Alum

Bluff was described in 1889 by D. W. Langdon' and the beds re-

ferred to the Miocene without differentiation. The name, Alum

Bluff, used for a geologic division or formation, was first employed

by Dr. W. H. Dan: The succession at Alum Bluff as given by

Dall' is as follows :

Section at Alum Bluff.

6. Yellow, unfossiliferous sand . . . . . . 5. Lignitic sand . . . . . . . . . . . . . . 4. Ecphora bed . . . . . . . . . . . . . . . 3. Alum Bluff beds . . . . . . 2. Marl (Chipola) . . . . . . . . . . . . . . 1. Chattahoochee limestone ( ?) . . . ..

Feet
. 70 . 10 . 30
. 15 . 5

The Alum Bluff formation, as described recently. by Matson and

1Amer. Jour. Sci.. 3d ser., val. 38, p. 324. 2Bull. U. S. G~ol. Survey No. 84, 1892, p. 122. 80p cit., p. 113.

ALUM BLUFF FORMATION

343

Clapp1 includes more strata than was originally included by Dall, as the Chipola marl is considered a member of the Alum Bluff formation. As now used in Florida, the term embraces 'all the beds lying between the Chattahoochee formation and the Miocene.
The divisions of the upper Oligocene, Parachucla and Combahee, made by Sloan2 on Savannah River, are the stratigraphic representa tives of the Alum Bluff formation, and their use is not continued in the present report.
DEFINITION
Stratigraphic relations.-The Alum Bluff formation conformably overlies the Chattahoochee formation; the exact contact between the two is in places drawn arbitrarily, since there is neither an abrupt lithological nor faunal change from one to the other. There may b~ apparent unconformities due to solution and weathering of the Chattahoochee limestone near the contact. On Savannah and Altamaha rivers the Oligocene is separated from the overlying Miocene by an erosion unconformity, perhaps of minor importance. Throughout the greater part of the area underlain by the Alum Bluff formation
n the Miocene is absent, and the Alum Bluff is overlain unconform-
ably by the Altamaha (Lafayette formation, with which it may, in places, be confused on account of a similarity in appearance when weathered.
Lithologic characters.-The Alum Bluff formation presents a number of different lithologic phases; these include coarse, angular sand,. co;1rse-grained, aluminous sandstone or grit, sandy clay, fullers earth, phosphatic sand, quartzites, sandstones, silicified clays, and local limestones or calcareous layers and nodules. Greenish or gray, argillaceous sands, and sandy, laminated clays, form the greater portion c1f the formation.
Beds of fullers earth occur in the formation both in Georgia ancl in Florida. The fullers earth is generally a gray or drab, faintly laminated, clay-like earth of low specific gravity. The earth is usually semi-hard and brittle, and in many places silicification has gonl' on to such an extent that the earth is very hard and rock-like, and no longer has the properties of fullers earth. Segregations of silica in the form of small, round, or flattened nodules is characteristic. Th:' fullers earth beds do not attain any considerable thickness and R'? not persistent over large areas but appear to be local phases in sands and sandy clays. Greenish and drab, sticky, plastic clays, and argillaceous sands, are associated with the fullers earth beds.
1 Second Ann. P~pt. Geol. surv~y of Florida, 190!l. p. 91. 2Catalogue of Mineral' Localities of South Carolina: Geol. survey of South' Carolina, ser. 4, Bull. No. 2, 1908, p. 273.

344

GEOLOGY OF THE COASTAL PLAIN

On Allapaha and Suwanee Rivers are phosphatic ~ands which are believed tD lie directly aoove the Chattahoochee formation. Sands of the Alum Bluff formation on Savannah River are also slightly phosphatic. These sands are generally unconsolidated, o,_. only slightly indurated, are sometimes coarse-grained, even containing small pebbles, and often display crossbedding. They con,ri,: largely of quartz ; the phm;phate is in the form of small, brown o!' black, slick, water-worn pieces of oones and teeth, varying in ,;i:r.c from a pin-head to one"half or three-fourths of an inch in diameter. A small amount of clay is generally present and the sands, in a number of places, are calcareous and contain calcareous, phosphatic nodules. The chemical analysis' of a sample of sand from the Suwanee River, nine miles below Fargo, showed 16.80 per cent. of phosphoric acid (P 0).
The clay and fullers earth phases of the formation have in places been silicified to such an extent that they have been converted .into very hard claystones, and the argillaceous sands have become dense, virtreous, and brittle quartzites; clay breccias and conglomerates have likewise been silicified. In fact greater or less degrees of alteration of the rocks by silica carried in solution by circulating waters has been extensive. Opal and agate occur in places as a result of this silicification.
Samples of the silicified clays from Withlacoochee River, seven miles east of Quitman, were examined in the laboratory. They vary from bluish to light greenish and dove color, are hard, brittl2, and break with a conchoidal fracture; the rock is dense and compact, and cracks are filled with opaline silica. Some of these rocks are slightly phosphatic. There are phases wh-ich might be termed opalized clay conglomerates or breccias; originally, this conglomeratic rock consisted of fragments of clay, either pebbles of clay or angula;_ fragments, in a matrix of very sandy, lighter-colored clay or argillaceous sand, the matrix often containing oyster shells. By the infiltration of opaline silica, the rock has become dense, rompact, and in places vitreous or glassy to such an extent that the sand grain,; are no longer recognizable. The clay is about 3 in the scale of hardness and it requires a strong blow with the hammer to break it. The lime of the oyster shells has been replaced by silica, and they ,ate opalized and agatized.
In Grady, Brooks and Thomas counties thin beds of white sandstone, usually soft, were noted. These sandstones are associated with sandy clays and are often phosphatic, the phosphate forming, ir1 part, the cementing agent.
1By Dr. Edgar Everhart, Chemist Geological Survey of Georgia.

ALUM BLUFF FORMATION

345

Thickness.-The maximum thickness of the Alum Bluff formation in southwe~tern Georgia is estimated to be 150 feet. At no known locality can the full thicknesll of the formation be seen in a natural exposure; the estimate here given is based upon the record of a deep well at Valdosta. Samples from the depths of 150 and 176 feet in this well bore a close resemblance to the indurated fullers earth of the Alum Bluff formation, and limestone, probably of the Chattahoochee formation, was encountered at 186 feet. No natural exposures revealing a thickness of strata more t~an 40 or 50 feet were seen. Judging from the record of the Waycross well, it is probable that the Alum Bluff formation at this point is as much as 250 feet thick.' At Lumber City, in Telfair County, there is some probability that the Alum Bluff formation is as much as 200 or 300 feet thick. The natural exposures on Savannah Rived do not exceed 25 or 30 feet.
Paleontologic characters.-The formation is, on the whole, poorly fossiliferous. The clays and sands generally contain only poorly preserved casts and impres.sions. Doctor Vaughan obtained a nuaber of species, listed on a subsequent page, in the vicinity of Bainbridge, and a well preserved oyster, Ostrea mauricensis, is found at a number of localities. The formation seems to mark the disappearance of the species of Orbitoides which are so common in the Vicksburg and Chattahoochee formation. On Savannah River the rme fossil,Carolia fioridana, and Pecten sayanus have been found in this formation.
Area,Z Distribution.-The Alum Bluff formation underlies a large area in Georgia, extending from Decatur County northeastward to Savannah River; the northern limit of sedimentation during the Alum Bluff period is approximately marked by Cordele, Abbeville, Dublin, Millen, and Sylvania. No evidence of its occurrence north of these points has been found. Southward or southeastward from these points it is highly probable that the whole of the Coastal Plain is underlain by this formation. Througout most of this area, however, it has been covered by later sediments, and natural exposures are largely confined to bluffs of rivers.
It is the surface formation, and it influences the soil and topography over a large part of Decatur, Grady, Thomas, Brooks, Lownde-5 aJJ.d Echols counties. Exposures appear in the bluffs of Ocmulgge and Altamaha rivers from near Abbeville to Doctortown. Alum Bluff strata may occur along Ogeechee River, but this has not been proven by paleontologic evidence. On Savannah River, the Alum

'Well record Underground waters of Georgia: Bull Geol. Survey of Georgia, No. 15, 1~08. p. 172.

346

GEOLOGY OF THE COASTAL PLAIN

Bluff formation is believed to extend from near Hudson's Landing to Porter's Landing in Screven County.

Physiographic expression.-The area over which the Alum Bluff formation is the surface formation, is small, although a distinctive topography has been produced by its erosion and weathering in the southern part of the State. In the southeastern part of Decatur and the southern parts of Grady, Thomas, Brooks and Lowndes counties, the Alum Bluff formation, together with the Chattahoochee formation, has produced a topography more broken and hilly than that of the Altamaha region to the north. This topography is due, in part, to thr> argillaceous and sandy character of the Alum Bluff formation. The formation is easily eroded and the numerous lime sinks of the region have given an impetus to this erosion.

Structure.-The Alum Bluff formation has a very low southwarci.

and southeastward dip, certainly much less than the older Eocene

and Vicksburg formations. On Savannah River, the dip dues no~

exceed four or five feet per mile, and near the Florida line the beds

must lie almost horizontally, since the streams have cut through them

exposing the underlying formations. No evidence of broad :flexures,

or even minor folding and faulting was observed in the natural ex-

posures of the strata. However, the probability of a broad arch ex-

isting in the southern part of the State has been mentioned in con-

nection with the discussion of the drainage, and general structure of

the Coastal Plain strata. (See pages 63-65.)



Economic geology.-The Alum Bluff formation contains beds of fullers earth which, locally, are sufficiently free from sand and siliceous concretions to be of commercial value. Fullers earth mining has been carried on at Attapulgus, Decatur County, for several year;;;, and a good quality of earth for clarifying mineral oils is produced. The Attapulgus earth is very similar to that at Quincy, Fla. Brief descriptions of the deposit at Attapulgus have been published by Vaughan' and Veatch'. The prospects are favorable for finding commercial deposits in Decatur, Grady, Thomas and Brooks counties.
Sands containing a considerable percentage of phosphoric acirl (P 0) were observed along the lower courses of Suwanee and Allapaha rivers, and these may prove to be of some value in the future as low grade phosphates.
The clays, while on the whole poorly adapted for burned cla,Yproducts, may be of some local value for common building brick.

'Vaughan. T. W., Bull. U. S. Geol. Surv. No. 213 1903. pp. 392-399. veatch, Otto, Clay deposits of Georgia, Geol. Survey of Georgia, Bull. 18, 1909, pp,

ALUM BLUFF FORMATION

347

LOCAL DETAILS

Baidbridge, Deca;tur County.-The following are notes by Dr.
Vaughan on localities southeast of Bainbridge, at Roseland planta-
tion, "Gastropod Gully" on the Bowers land, and on the Dickson
farm, in Decatur County. Lists of fossils from the first two localities
are furnished. "Gastropod Gully" was named by Dr. A. F. Foerste'
who made a study of the beds and referred them to the Chipola of
Florida.
"Campbell Htll, Roseland plantation.-The hill is composed of reddish and yellowish, residual sands. At the northeast corner of the hill, immediately west of a small ravine, a pile of yellowish, reddish, or whitish, siliceous sandstone, rich in fossils, was found. The fossils collected here belong to the same horizon as thore in Judge Bowers' and Sam Dickson's fields. Some 20 or more species of mollusks were collected and listed as follows:

List of fossils from Campbell Hill Roseland Plantation.

Pleurotoma servata Conrad ? Pleurotoma Fulgur spiniger Conrad Melongena Latirus? Nassa Astyris ? Astyris ? Bittium Serpulorbis ?

Crucibulum auricula Gmelin Natica alticallosa Dall. Omphalius exoletus Conrad. Fissuridea sp. Area staminata Dall ? Area sp. Spisula sp. Strigilla sp. Venus sp. Carditamera sp.

Gastropod Gully, Bowers' Land. This gully is on Judge Bowers' land, east of Roseland plantation. It is 12 to 15 feet deep with almost perpendicular walls. The E>ides are composed of yellowish sands and of bluish clayey sands blotched with yellow. Bits of siliceous material are common and residual pieces of usually yellowish apparently silicified sandstones are abundant. Near the head of the gully it is shallower, and the residual sandstone is strewn promiscuously over the surface. Most of the fossils were found here. The gully is only about two hundred yards long.
Gastropod Gully is therefore, according to aneroid barometer readings,
85 feet above the level of Bainbridge at Hotel Wainman.

List of fossils from southeastern corner of Bowers' field, Foerste's Gastropod Gully locality.

Conus (probably planiceps Heilprin) Pleurotoma Marginella Turbinella ? Fulgur spiniger Conrad Mazzalina ? Melongena Murex Nassa (Chippola species) Latirus? Bittium
Turritella indenta vat. mixta Dall. Turritella alcida Dall. Turritella 2 other species
Solarium granulatum var. chipo-
lanum Dall.

Crepidula Crucibulum auricula Gml Natica alticallosa Dall. Fissuridea (2 undetermined gastropods). Area staminata Dall. Area santa rosana Dall. Pecten chipolanus Dall. Spondylus '! Carolia (probably floridana Dall). Mactra ( Spisula) sp.
Mactra ? Strigilla (related to flexuosa Say). Tellina (Angulus).

'Amer. Jour. Sci., vol. 16, October 1893, pp. 245-254.

348

GEOLOGY OF THE COASTAL PLAIN

"Sam Dickson's farm, six miles southeast of Bainbridge. . In a field across a small branch, on the south side of the road, are numerous boulders containing fossils. The material was originally a limestone but has been altered to a chert; it is yellowish in color, or occassionahy reddish, and is similar to that found in the Bowers pasture. These boulders are residual
masses left in yellowish or whitish sands. The fossils are poor casts or siliceous replacements and are the same as those found in the Bowers pasture. A small collection was made. The horizon is in the Alum Bluff formation."

Climax, Decatur County.-In the vicinity of Climax, are anumber of exposures of gray, fine-grained, clayey sands, and greenish, plastir-, Eandy clays which are probably referable to the Alum Bluff formation.
A section of much stratigraphic interest is revealed in the cuts of the Atlantic Coast Line Railroad and an adjacent gully threequarters of a mile west of Climax. The lower part of this section, from the level of the branch to the level of the track, consists of gray or greenish, laminated, sandy clays, and greenish or bluish clayey sands, considered referable to the Alum Bluff formation. They contain no fossils, and their stratigraphic position is inferred from their lithologic character, geographic position, and relation to the overlying formation. The section of this. exposure given bPluw has been furnished by DL Vaughan, and it will be further discussed in connection with the description of the Altahama (Lafayette ?) formation.

E:x:posure Jn north side of railroad, one mile west of Climax, from

about twenty feet below to thirty feet above the level

of the railroad.

Pliocene ?

Feet In.

Altamaha formation.

15. Soil and humus . . . . . . . . . . . . . . . . . . .

5

14. Yellow sand, some small gravel . . . . . . . . . . 5

13. Mottled sands and clay . . . . . . . . . . . . . . 5

12. Sands and some clay, showing stratification dis-

tinctly, whitish, yellowish, reddish, upper 20

feet crossbeded and ferruginous sandstane . . . 25

Oligocene.

Alum Bluff formation.

11. Clays blotched reddish ( a:bcut two feet below level of

railroad) . . . . . . . . . . . . . . . . ...... .

i)

10. Stratified sands and clay, blotched red . . . . . . .

6

9. Stiff clay, blotched red . . . . . . . . . . . . . .

2

8. Whitish sands with seams of clay . . . . . . .

3

7. Stiff blue clay, blotched red . . . . . . . . . . . . .

1

6. Finely laminated sand and clay . . . . . . . . . . . . . 2

5. Bluish clay resembling fullers earth, specimen col-

lected, about . . . . . . . . . . . . . . . . . . . . . 1

4. Whitish sands . . . . . . . . . . . . . . . . . . . . . . . . . 3 6

3. Clay similar to No. 1, some of which resembles ful

lers earth . . . . . . . . . . . . . . .

. .... . 2 6

2. Whitish sand, a little clay . .

. . . . .. . 6 9

1. Fine, sandy, bluish clay . . . . . . . . . . . . . . . 1 6

ALUM BLUFF FORMATION

349

"The lower portion of the section to No. 10, inclusive, was measured; the remainder was estimated and then checked by aneroid."

At Mashburn Hill, four miles north of Climax, approximately 60 feet of clay5 and sands are exposed which are here referred to the Alum Bluff formation. The bed consists of greenish, plastic, nnd vm) sandy clays, showing little stratifi!'~tion, in planes thin interbedded layers of pure whitP sand. They are fine-grained, are free from pebbles, and contain white, irregularly-shaped, ant flattened nodules of silica. They are overlain by yellow, ll;rgillacPous sand, (('lltaining black iron oxide concrctiJns, eviaently a
n product of weathering. The underlying clays and sands have been
previously described by Yeatch' as the ),Jtamaha (Lafayette formation, but the detailed study of the Alum Bluff formation subsf'quently undertaken has lead to the belief that they are referable to the Alum Bluff formation. This conclusion is reached on the basis of lithologic character.
Attap1tlgus, Decahtr County.-Attapulgus is located 13 miles south of Bainbridge, Decatur County. There are a number o exposures of sandy clays and fullers earth, which belong to the Aluw Bluff formation, The fullers earth is of commercial value and is being mined. It has been described by Dr. Vaughan; and the chemical and physical properties of both the clay and fullers eartb have been described by Yeatch:
The pit of the Lester Clay Company, when visited in .October, 1908, showed:

8edion at pit of Lester Clay Company.

Age ?

Feet

4. Red; sandy clay covering slope . . . . . . . . .

?

Alum Bluff formation. 3. Stiff, tenacious, structureless clay apparently residual. 6 to 10 2. Fullers earth . . . . . . . . . . . . . . . . . . . . . . . . . . 6 to 10

1. Hard, greenish or drab, argillaceous sandstone . . .

7

'
The fullers earth presents very little structure; it is faintly lami-

nated, the lines of stratification appearing only when the earth is

dry. It is jointed and scales of manganese oxide often appear along

the cracks. When moist, the earth is dull olive green in co~or, and

slick or unctuous to the touch; when dry, it is white and brittle.

It is distinguished from the greenish clays of the Alum Bluff for

mation by its low specific gravity, and high porosity; when dry it

adheres strongly to the tongue.

'GeoL Surv. of Ga., BulL 18, p. 316.
'r. S. Geol, Surv., BulL No. 213, p. 392.
3Grol. Surv. of Ga., BulL No. lR. pp. 317-318.

350

GEOLOGY OF THE COASTAL PLAIN

'The section revealed in the public road leading east from the station Is:

Section in public road east of Attapulgus station.

Age?
4. Red sand, in places argillaceous, capping the ridge . Alum Bluff formation.
3. Plastic, greenish clay . . . . . . . . . . . . . . . . 2. Gray, very sandy clay . . . . . . . . . . . . . . . 1. Bluish and greenish, stiff plastic clay . . . . . . . .

Feet
. 15
. 4 . 15 . 15

The red sand layer, No. 4, probably bolongs to the Altamaha (Lafayette?) formation.
In the railroad cut, one mile south of Attapulgus station, there is four feet of white or gray, very sandy claystone or sandstone, which contains poorly preserved fossils; this is overlain by a thin bed of shaly, brittle fullers earth and plastic clay, and probably represents the sandy bed observed in the bottom of the fullers earth pit.
Whigham and Cairo, Gradry Oounty.-'The topography in the vicinity of these towns is broken and there are a number of exposures where the character of the Alum Blu:ff and its relations to the overlying Altamaha (Lafayette?) formation may be seen. The Alum Blu:ff formation consists mainly of greenish or gray, sandy, massive clays, thin beds of fullers earth, and gray and white phosphatic sandstones.
In a cut one mile east of Whigham, a bed of light greenish clay, somewhat in the nature of fullers earth, is overlain by orange-colored sands, and clays and sands alternately stratified: The clay bed shows some slight crumpling. It probably represents the Alum Blu:ff formation, while the overlying sands belong to the Altamaha (Lafayette?) formation.
The conformable relations of the Alum Blu:ff formation to the Chattahoochee limestone are revealed at Forest Falls, or Limesink, eight miles northwest of Whigham. The formation is mainly a sandy, compact clay and contains characteristic Alum Blu:ff fossils. This section has been described in detail on page 334.
In the cuts of the Atlantic Coast Line Railroad west of Cairo, the greenish, sandy clays of the Alum Blu:ff formation rise as high as 12 to 15 feet above the track and are unconformably overlain by the mottled sands and sandy clays of the Altamaha (Lafayette?) formation. On Tired Creek, three and a half miles west of Cairo, a cut reveals fossiliferous sandstone of the Alum Blu:ff formation.

ALUM BLUFF FORMATION

351

Section on Tired Creek.
Feet Alum Bluff formation.
4. -Stiff, bluish or greenish clay, weathering brown . . . . 3 3. Very thinly laminated fullers earth . . . . . . . . . . 1 2. Soft, argillaceous, white sandstone, fossiliferous; contains
Ostrea, Carditamera tegra, Chione, Venus. . . . . . . . 1 1. Pale-green, non-laminated clayey sand . . . . . . . . . 5
A white sandstone, locally altered to quartzite, occurs on the Ragan plantation on Buck Creek, 10 miles south of Cairo. The sandstone is overlain by a "gummy," greenish clay with laminae of fullers earth. This sandstone is quarried for local building purposes.
Ocklockonee River.-The Alum Bluff formation is exposed along Ocklockonee River from the southern part of Colquitt County through Thomas and Grady counties to the Florida line. It consists of greenish or gray, compact sands, greenish clays, and gray, argillaceous sandstones. Poorly preserved fossils were found at some localities. It is often difficult to distinguish the formation, especially where weathered, from the overlying Altamaha (Lafayette?) formation. The contact between the two is revealed, howeV'er, east of Pine Park, in the cuts of the Atlantic Coast Line Railroad near the river, at mileposts 203 and 205. Near the FloridaGeorgia line the river has cut through the clays, exposing limestones which probably belong to the Chattahoochee formation.

Thomasville and Boston, Thomas County.-In the hilly region south of Thomasville, and in the vicinity of Boston, the Alum Bluff formation is the main surface formation and, together with the Chattahoochee limestone, has determined the character of the topography, and to a considerable extent the character of the soil. It consists largely of gray and greenish clays, and compact, argillaceous sands, which upon weathering, produce red and brown sands and sandy clays. Layers of white, phosphatic sandstone occur which appear at the surface as brownish, both angular and rounded fragments strewn through the soil. Oyster shells are the common fossils, but associated with them are corals which were probably weathered from the underlying Chattahoochee formation. The weathered Alum Bluff materials might be easily confused with the Altamaha (Lafayette ?) formation. At the few places where the Altamaha (Lafayette?) could be recognized it consisted of crossbedded, varicolored quartz sand and mottled, sandy clays. The Alum Bluff formation is distinguished by its greenish clays, usually containing foPPils, and by its phosphatic sandstones.

352

GEOLOGY 0~' THE COASTAL PLAIN

The best exposures revealing the character of the Alum Bluff formation in this part of the State are at the old Toy phosphate pit, three and one-half miles west of Boston; a hill on the Mallet plantation on the Boston-Monticello road, four and one-half miles southwest of Boston; and at the Mcintyre plantation, 11lj2 miles south of Thomasville. Sandy clays of the Alum Bluff formation overlie the Chattahoochee formation at these localities.
Greenish quartzite and quartzitic conglomerate, similar to that on vVithlacoochee River, seven miles east of Quitman, appear on the Mitchell plantation, six and one-half miles east of Thomasville. This rock contains a small percentage of phosphoric acid. The underlying Chattahoochee formation also outcrops at this place.
Withlacoochee River.-The Alum Bluff presents a variety of phases along the course of Withlacoochee River and its relations to the Chattahoochee formation may be seen.
At Old Troupville, four and one-half miles northwest of Valdosta, about 15 feet of Alum Bluff strata is exposed in a bluff of Little River near its junction with the Withlacoochee; the rock here might be described as an argillaceous sandstone. There is a thin layer which contains poorly preserved fossils; Turritella, Area, and agatized oysters were noted. In places, the rock has a brecciated or conglomeratic appearance, and is slightly calcareous and phosphatic.
At the Atlantic Coast Line Railroad bridge, seven miles east of Quitman, the channel of the stream is cut into a hard, greenish or bluish claystone. This rock is a semi-indurated or very hard rock, which was probably originally in the nature of fullers earth, but is now hardened by the infiltration of opaline silica which has form( the cementing substance of the rock. It contains knots or nodules more siliceous than the matrix, in some of which finely crystalline pyrite was observed. The rock does not show any distinct lamination or bedding.
The left bank of the river, one-half mile below the railroad bridge, exposes the following section:

Sect.ion left bank of river, one-half mile below Atlantic Coast Line Railroad bridge.

Pleistocene.

Feet.

4. Slope of incoherent, gray sand . . . . . . . . . . . .

. 15

Oligocene.

Alum Bluff formation.

3. Compact, clay breccia and quartzite . . . . .

. 8

2. Fullers earth-like clay containng siliceous and calcare-

ous nodules . . . . . . . . .

. 15

Chattahoochee formation.

1. Limestone, covered by water . . . . . . . . .

. ?

GEOLOGY OJ.' 'l'RE COASTAL PLAIN OF GEORGIA.

PLATE XXV.

A. EXPOSURE OF PARTIALLY INDURATED. PHOSPHATIC, CALCAREOUS ::>AND OF THE ALUM BLUFF FORMATION. ALLAPAHA RIVER, STATENVILLE. ECHOLS COUNTY. BLUFF AND ALTAMAHA FORMATIO::\'S.

ALDM BLDFF FORMATION

353

Beds 2 and 3 are referred to the Alum Bluff formation. No. 3 is in places a vitreous and brittle, amorphous silica, having imbedded in it pebbles and fragments of greenish clay; where unaltered it is a conglomerate of sand and green clay or fullers earth. The fullers earth is greenish and unctuous when moist, and drab and brittle when dry; it contains nodules of silica, often agate, and calcareous, earthy layers and nodules. No unconformity between layers Nos. 3 and 4 was noticed, although the conglomerate character of layer No. 4; suggests that the underlying clays were eroded during its deposition. The only fossils observed were oysters, which were imbedded in the silicified conglomerates.
The relation of the clays to the limestone of the Chattahoochee formation was observed in the bluff on the west side of the river two and one-hal miles below the railroad bridge, near Stony T_,ake.

Section near Stony Lde.

Feet

Pleistocene.

3. Gray and brown sand covering the upper slope of the

bluff . . . . . . . . . . . . . . . . . . . . . .

. 20

Oligocene.

Alum Bluff formation ?

2. Greenish and drab, semi-indurated fullers earth .

. 14

Chattahoochee formation.

1. Limestone . . . . . . . . . . . . . . . .

. 4

The fullers earth is brittle and crumbles when dry. It contains siliceous nodules. At one point a bed was observed which was thought to be a transition layer between the fullers earth and the limestone. It consisted of one or two feet of soft clay and sandy marl, containing numerous fragments of shells, Pecten, echinoids, Orbitoides and pieces of bones. No evidence of an unconformity between the limestone and the fullers earth was observed.
At Knight's Ferry, 11 miles southeast of Quitman, the Alum Bluff formation is a semi-indurated clay or fullers eartl>, partly silicified. The bed of the river at low water is strewn with fragments of chalcedony, agate, and white, rounded nodules or concretions of silica. About one mile above the wagon bridge there is a picturesque fa]] in the river caused by a bed of semi-indurated, sandy fullers earth protruding six or eight feet above the water and forming large boulders in the channel.

Allapaha River.-The nothernmost exposure of the Alum Bluff formation observed on Allapaha River is near Willacoochee, Coffee County, where two feet of stratified, fine, sandy clay appears in the left bank of the rivPr, overlain unconformably by later sediments.

354

GEOLOGY OF THE COASTAL PLAIN

The following section appears in the east bank of the river at the bridge two miles east of Milltown:

Section two miles east of Milltown.

Feet In .

Pleistocene (terrace deposit)

3. Brown or chocolate-colored, compact sand . . . . . 5

2. Pebbly sand, greenish quartzite, and white phosphate

pebbles . . . . . . . . . . . . . . . . . . . . . . . . . 1 6

(Unconformity)

Oligocene.

Alum Bluff formation.

1. Greenish, sandy clay, containing siliceous and cal

careous. nodules . . . . . . . . . . . . . . .

8

Laminated, greenish or drab clays were thrown from a well near the old brick yard west of Stockton, and natural exposures of gray or greenish, sandy clays occur at Hotchkiss Mill, three and one-half miles northwest, and in the banks of the river at Milltown.
On the lower courses of Allapaha and Suwanee rivers in Georgia, the greenish, sandy clays, fullers earth, and quartzites seem to be represented by phosphatic sands. The sands are unconsolidated or only slightly compacted, in places are calcareous, and are made up principally of coarse, quartz sand and black and brown, water-worn particles of bones and teeth which vary from a pin-head to threefourths of an inch in diameter. They contain only poorly preserved fossils, not sufficient to .determine their age, but they directly overlie limestone which has the characteristics of the Chattahoochee formation. The only fossils which have been secured from these sands are a Scutella, from Statenville, and a Pecten related to P. madisonius from Suwanee River, 14 miles south of Fargo, together with poor prints of an oyster, and unidentifiable casts.
In the river bank and in a ravine a few rods below the wagon bridge at Statenville, Echols county, 14 feet of phosphatic sand is exposed. It is a coarse, gray, calcareous sand, full of brown and black, phosphatic particles. The sand becomes decidedly coarse, almost pebbly. Thin limestone layers occur in it, and it is strikingly crossbedded, the lines of stratification dipping 20 to 30 degrees from the horizontal. The phosphatic particles vary from the size of a pin-head to one-fourth or one-half inch in diameter.
Phosphatic and conglomeratic limestone of the Chattahoochee formation appears along the river below Statenville, in places rising as high as 10 or 12 feet above low water.
Exposures of phosphatic sands and greenish, laminated, sandy clays, similar to the material on the Allapaha, have been noted by Mr. S. W. McCallie' on the Allapacoochee near the State line.

1Geol. Surv. of Ga., Bull. No. 5-A. p. 82.

ALUM BLUFF FORMATION

355

Suwanee River.-Suwanee River has its source m Okefenokee Swamp and flows through a low, flat, sandy plain. The river has formed no high bluffs, and exposures of strata other than surficial gray or white sands of Pleistocene age are rare and may be seen only at very low water.
Beneath the railroad bridge at Fargo is a greenish, sandy, finegrained clay which appears about one foot above low water. It is overlain by brown, incoherent, quartz sand, a Pleistocene terrace deposit. The greenish clay probably belongs to the Alum Bluff formation, although it contains no fossils, and its age is inferred from its lithologic appearance.
At Bony Bluff, nine miles southwest of Fargo, three feet of gray, compact, calcareous sand probably belonging to the Alum Bluff formation appears at very low \YUter. This sand is full of black, phosphatic pellets from the size of a flax-seed to one-onrth inch in diameter, and also contains large fragments of blackened bones, sharks' teeth and poorly preserved prints of shells. The phosphatic sand is overlain by eight t,) ten feet of brown and white sand of Pleistocene age. Large fraguents of silicified wood not in place occur, but they probably came from the base of the Pleistocene sand.
Similar phosphatic sand was found at "The Rocks" or "Rocky Ford," five miles below Bony Bluff, and one-half mile above the Georgia-Florida State line. The bluff of the river at this point is 12 feet high at low water. The rock is in the bed of the river, but when the water is very low about one foot of it is exposed. It is a buff-colored sand, compacted by calcium carbonate; it is slightly more indurated than that at Bony Bluff and contains nodules of stone harder than the matrix, which appear to be due to segregations of calcium carbonate. Bones and prints of shells are abundant; two species of Pectens, an oyster, and a number of obscure casts occur. Dr. Vaughan has identified Pecten madisonius from this locality, and states that, although the formation here is provisionally classed as Oligocene, it may be Miocene.
The phosphatic sands on Suwanee River and on Allapaha River are similar in apiJearance, and probably occupy the same geological position, namely, directly above the Chattahoochee formation, and there may be a continuous sheet of these sands between the two rivers. The greater part of Echols, Clinch, and Charlton counties is a very level, sandy plain, and only Allapaha, Suwanee, and St. Marys rivers have cut through the Pleistocene surficial sand. The smaller streams have low, sandy banks, or flow through swamps, and since they have not cut through the sands, exposures of the older formations do not appear.

356

GEOLOGY OF THE COASTAL PLAIN

St. Marys River.-The occurrence of the Alum Bluff on St.

Marys River is doubtful. If exposed at all, it is only along the

upper 25 or 30 miles of its course after its issuance from Okefenokee

Swamp. St. Marys River flows through a flat plain underlain by

Pleistocene sand, and is generally bordered by low sand banks. The

following section was observed at Smith Bluff, six miles north of

MacClenny, Florida:



Section at Smith Bluff St. Marys River.

Feet In.

Pleistocene.

6. White sand . . . . . . . . . . . . . . . . . . . . . .

2 6

Age?

5. Weathered clay and sand, red mottling . . . . . . . 2 6

4. Clay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

3. Brownish, quartz sand . . . . . . . . . . . . . . . . . . 1

2. Bluish, or drab clay . . . . . . . . . . . . . . . . . . . . 4

Oligocene ?

Alum Bluff formation ( ?)

1. Bluish-gray sand, containing a small amount of dis-

seminated clay, sufficient to make the sand com-

pact, and mii).ute phosphatic particles . . . . . . . 15

No fossils were observed either in the upper or lower part of the bluff. Lithologically the lowest stratum is not wholly unlike some of the Alum Bluff clayey sands observed at localities in Georgia. Beds 2, 3, 4, and 5 perhaps belong to the Altamaha (Lafayette ?) formation.
Inasmuch as younger fossiliferous beds are found at Stokes Ferry, 11 miles south of St. George, it is not probable that the Oligocene extends further than the eastern angle of the river, in southern Charlton County.

Ocmulgee River.-Certain strata appearing in the bluffs from near Abbeville on Ocmulgee, to Doctortown on Altamaha River, are referred to the Alum Bluff formation. The age of these beds has been largely determined by their petrologic character and their stratigraphic relations to other formations. Conclusive paleontologic evidence of their age is wanting: They are underlain by lower Oligocene limestone and are overlain by beds of Pleistocene, Pliocene ( ?) , and Miocene age. The presence of the Chattahoochee formation underlying these Alum Bluff beds has not been demonstrated, although there is a suggestion that the Chattahoochee formation exists near Hawkinsville and Abbeville where silicified corals have been found.
. A number of sections of bluffs will be given to indicate the lithologic character and the relations of the Alum Bluff formation to other formations.

A.LUM BLUFF FORMATION

357

The following succession of beds appears at House Creek bluff, two miles east of Bowens Mill, Wilcox County:

Section at House Creek Bluff, Ocmulgee River.

Feet In.

Pleistocene (terrace deposit)

Okefenokee formation.

8. Thin covering of gray sand . . . .

7. Mottled, red and yellow sand or loam .

30

Oligocene

Alum Bluff formation.

6. Greenish, fine textured clay containing sand pockets

and siliceous nodules . . . . . . . . . . . . . . . . . . 10

5. White, calcareous sandstone . . . . . . . . . . . . . 5

4. Bed of oyster shells in a calcareous, sandy matrix . 2 6

3. Greenish, clayey sand with calcareous concretions . 3

2. Greenish, laminated, sandy clay . . . . . . . . . . .

4

1. Gray, compact sand . . . . . . . . . . . . . . . . . . . . 5

The oyster-bearing beds of this locality are mentioned by Dall' as "presenting such a petrologic character as the Hawthorne beds of Florida." The Hawthorne beds are now regarded as approximately the age equivalent of the Chattahoochee.' Certainly the lithologic aspect of the beds at House Creek is more like that of the Alum Bluff formation of southwestern Georgia than of the Chattahoochee formation of the same region.

Section of Bluff at Lumber City, Telfair County.

Feet

Pleistocene (terrace deposit)

4. Thin covering of gray sand, level of second terrace

3. Coarse, gray and red, pebbly sand; coarse pebble layer

at base . .

. . . . . . . . . . . . . . . . . . . 15

(Unconformity.)

Oligocene.

Alum Bluff formation.

2. Interstratified layers of greenish clay, and yellow and

white, unconsolidated sand . .

. . . . . . . . . . 10

1. Greenish and drab, sandy clay . . . . . . . . . . . . 15

No fossils were found here except in limestone fragments at the base of the Pleistocene.
In the bluff at Quinns "Fractions," four miles below Lumber City, similar sandy clays, together with a bed of vitreous quartzite, are exposed.
1U. S. Geol. Survey, Bull. No. 84, p. 81. 'Matson and Clapp, Fla. Geol. Surv. 2d Ann. Rept. 1909, p. 70.

358

GEOLOGY OF THE COASTAL PLAIN

Section at Quinns "Fractions/' Ocmulgee River.

Feet

Age ?

5. Upper slope of bluff, strata concealed . . . . . . . 20 to 30

Alum Bluff formation.

4. Bed of quartzite, expbsed . . . . . . . . . . . .

1

3. Gray, compact sand containing clay laminae; contains

poorly preserved prints of fossils . . . . . .

12

2. Gray sand slightly indurated . . . . . . . . . . . . . . . . 3

1. Greenish laminated clay with sand partings . . . . . . . 5

At Oaky Bluff, two miles above the junction of Ocmulgee and Oconee rivers, thin slabs of greenish, brittle quartzite similar to that at Quinns "Fractions" appear. This is a low Pleistocene bluff and the quartzite extends only two feet above low water. Similar rock occurs on the Altamaha and probably lies in the channel of the river at Town Bluff, and also appears in the right bank of the river just above N ayles Ferry.

Oconee River.-Good exposmr of beds, questionably referred to the Alum Bluff formation, occur at several bluffs on Oconee Hiver. The materials are not typical of the Alum Bluff deposits, but differ from them only in being coarser and more irregularly-bedded; some of the coarser phases resemble the materials of the Altamaha (Lafayette?) formation.
Exposures have been examined at Berry Hill Bluff, J oyces Bluff, Stallings Bluff, and other bluffs between Dublin and the mouth of the river. Berry Hill is 55 miles above the mouth of the river and 10 miles' west of Soperton.

Section at Berry Hill Bluff.

Age ? 3. Loose gray sand and gravel on upper slope
Alum Bluff formation. 2. Gray, alluminous sandstone, forms a precipice . . . . 1. Sandstone and claystone, softer than the above . .

Feet
50 15

The sandstone is an indurated, coarse, feldspathic, quartz sand with disseminated greenish clay, the whole slightly cemented by silica. The rock varies from a claystone to a coarse sandstone almost a conglomerate. No fossils \\'ere found.

J oyces Bluff, t uo miles above Seaboard "1ir Line brid.r;e.

Alum Bluff formation. 9. Mottled grit . . . . . . . . . . . . . . . . . . . . . . 8. Gray, fine-grained, aluminous sandstone . . . . 7. Drab claystone, containing coarse quartz grains 6. Gray sandstone 5. Hard clay . . . . . . . . . . . . . . . . . . .

Feet.
10 5 3 4 1

ALUM BLUFF FORMATION

359

4. Fine-grained sandstone . . . . . . . . . . . . . 3. Greenish, massive, sandy clay . . . . . . .. 2. Gray sandstone . . . . . . . . . . . . . . . . . . . . 1. Drab, sandy clay . . . . . . . . . . . . . . ....

Feet In.
2 5 6 1 6
6

Section of lower end of Joyce's Bluff.

Feet

Age ?

9. Upper slope, concealed . . . . . . . . . . . . . . . . . . . 20

Alum Bluff formation.

8. Fine-grained, gray sandstone . . . . . . . . . . . . . . . .

3

7. Coarse, feldspathic, conglomerate, crossbedded; pebbles

an inch in diameter . . . . . . . . . . . . . . .

7

6. Fine-grained sandstone . . . . . . . . . . . . . . . . . .

1

5. Massive, drab clay . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4. Fine-grained, sandy clay, indurated and jointed . . .

4

3. Yellowish sand . . . . . . . . . . . . . . . . . . . . . . .

1

2. Feldspathic sandstone or grit . . . . . . . . . . . . . . . . . 1

1. Greenish and gray, friable sandstone . . . . . . . . . 8

Stallings Bluff, two miles west of Mount Vernon, is 45 feet high and is made up of rock similar to that at Berry Hill and J oyces Bluff. No fossils were found.

Altamaha River.-One of the best exposures of the Alum Bluff on Altamaha River is in the bluff at Grays Landing, 10 miles below the forks.

Section at Grays Landing.

Feet

Age ?

9. Incoherent gray sand, containing coarse gravel . . .

2

Pliocene.

Al\amaha (Lafayette ?) formation.

8. Mottled coarse sand and clay . . . . .

8

7. Gray feldspathic sandstone or grit . .

20



Unconformity ( ?)

Oligocene.

Alum Bluff formation.

6. Gray or greenish sand, compacted by disseminated clay . 6

5. Greenish or gray sand, containing less clay than the

overlying bed . . . . . . . . . . . . . . . . . . . . . . . . 5

4. Greenish or drab clay . . . . . . . . . . . . . . . . . . . . 2

3. Massive sand containing clay layers an inch or two thick 6

2. White, jointed, and laminated fullers earth . . . . . . . 6

1. Compact sand and claystone . . . . . . . . . . . . . . 1

The fullers earth is very similar in appearance to the fullers earth of southwestern Georgia.
The Alum Bluff formation is represented at Upper Sister and Lower Sister bluffs, 48 and 49 miles, respectively, below the forks. The Alum Bluff strata exposed in the bluffs reach a thickness of

360

GEOLOGY OF THE COASTAL PLAIN

30 or 40 feet and consist of gray or greenish,. aluminous sands and laminated, gray or greenish, sandy clays. The upper parts of the bluffs consist of coarse, feldspathic grit, the age of which is in some doubt. No fossils were found. These localities will be further discussed nnder the chapter on the Altamaha (Lafayette?) formation.
At Fort James, 58 miles below the forks, the lower part of the bluff, consists of fine-grained, almninous, compact sand, gray or greenish in color, and is probably Oligocene. This material is overlain by coarse-grained, more feldspathic beds.
The Alum Bluff formation at Oglethorpe Bluff, eight and onehalf miles above Doctortown, is exposed to a thickness of 15 feet and is unconformably overlain by unconsolidated sand and clay of the . Altamaha (Lafayette?) formation. lt consists of greenish clays, and gray or greenish, compact, aluminous sands.
The Alum Bluff formation, consisting of coarse, bluish or greenish, aluminous, compact sands, occurs at Linden, Bugs, and Doctortown bluffs, where it is unconformably overlain by Miocene strata. Sections at Bugs Bluff and at Doctortown will be described under the chapter on the Miocene.
The last high bluffs on the river are the Upper and Lower Sansavilla bluffs, 27 and 282 miles, respectively, below Doctortown. There is a small thickness of coarse, crossbedded sand which may represent the Oligocene. The_ section at the lower bluff is:

Section at Lower Sansarilla Bl1tjf.

Feet

Pleistocene.

3. Fine, brown and white sand . . . . . . . . . . . . . . . . 15

2. Sand containing thin layers of white or drab, laminated

clay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Oligocene ?

Alum Bluff formation (?)

1. Coarse, crossbedded, bluish, aluminous sand

8

Ogeechee River.-The Alum Bluff formation occurs at t\\o localities on Ogeechee River. A ;;haly, fullers earth-like clay and a greenish or gray siliceous n,laystone are exposed on the west side of the river, about one mile west of Rocky Ford. This rock rises about '20 feet above the water. No fossils were observed.
At Indian Head, three miles west of Egypt, Effingham County, two and one-half feet of sandstone, containing pockets of greenish, silicified clay, occurs in a slough on the property of Carl Higgins.
The rock at these localities are referred to the Alum Bluff formation pmely upon the bm:is of lithologic character and geo-
graphic position.

ALUM BLUFF FORMATION

361

Savannah River.-The northernmost exposure of the Alum Bluff formation on Savannah River was noted at Hudsons Landing, Screven County, 68lf2 miles above Savannah. The following section is exposed at the base of the bluff near the boat landing:

Section at base C:f bluff near Hudsons Landing.

Alum Bluff formation.

Feet In.

3. Pale green, thin, calcareous clay containing indis-

stinct impressions of leaves . . . . . . . . . . 0 1 to 2

2. Hard, sandy claystone, poor prints of fossils . . 0

3

1. To water's edge, dark green, coarse sand, argil-

laceous and compact; poor prints of fossils . . . 1

About 300 yards above the landing a bed of compact sand and finegrained clay co:qtaining prints of fossils appears in the bluff 25 feet above the river; it is probably referable to the Alum Bluff formation. The presence of beds of upper Oligocene age at this locality has not been proven by fossils. The beds here lie above the Chattahoochee and Vicksburg formations, which appear at the surface to the northward and the succession of beds is similar to that at Porters Landing where beds of upper Oligocene age have been recognized by fossils; the stratigraphic position of the lower beds at Hudsons Landing is, therefore, inferred to be that of the Alum Bluff formation.
The following is a section of a bluff one-half mile below Hudsons Landing:

Section of bluff one-half mile below Hudsons Landing.

Feet

Pleistocene ( ?)

7. Gray, surficial sand . . . . . . . . . . . . . . . . . . . . . .

2

Pliocene ?

Altamaha (Lafayette ?) formation.

6. Coarse sand containing a small amount of clay, mot-

tled red and gray; thin line of quartz pebbles at base. 30

(Unconformity)

Miocene.

5. Brown, fine-grained sand . . . . . . . . . . . . . . . 7

Miocene (?)

(Unconformity)

4. Yellow and gray, unconsolidated sand; thin line of flat

and discoidal quartz pebbles at base . . . . . . . . 20

(Unconformity)

Oligocene.

Alum Bluff formation.

.

3. Light greenish, sandy clay, faintly laminated

6

2. Greenish-gray or ash-colored, compact sand . . . . . . . 11

1. Red and brown, compact sand . . . . . . . . . . . . . .

4

As no well preserved fossils were found the correlations indicated ~in the preceding section are tentative.

362

GEOLOGY OF THE COASTAL PLAIN

In a bluff one mile below Hudsons Landing, Alum Bluff strata rise 30 feet above the river. They consist of greenish, compact, argillaceous sands which are massive and not laminated. No fossils were observed in these sands. The formation is separated from the overlying strata by a thin bed o.f nodular, fossiliferous, Miocene limestone containing M ytil:us conradinus d'Orbigny.
The Alum Bluff formation appears in the lower part of a bluff at Porters Landing, 62 miles above Savannah. Sloan' was first to recognize the stratigraphic importance of this section and has made a careful study o.f it. The Porters Landing exposures are described in dEtail on pages 371-373 of this report.

MIOCENE
In earlier geological literature on the Atlantic and Gulf Coastal Plain the term Miocene included beds which are now placed in the Oligocene. For example, the Chattahoochee and Alum Bluff formations were formerly described as :Miocene. Under the Miocene were included all the beds between the Vicksburgian and the Pliocene or Pleistocene. The necessity of a division, however, was recognized, and Dr. W. H. Dall distinguished the "old or subtropical Miocene" and the "new or Chesapeake Miocene." The "old Miocene" is now referred to the Oligocene division of the Tertiary, a discrimination due largely to the studies of Doctor Dall.' The Miocene here described refers only to that portion formerly designated "new or Chesapeake," which includes the strata lying between the Alum Bluff formation, and the Pliocene or Pleistocene. A summary of correlations of Tertiary horizons, according to the new classification, has been given by Doctor Dall. The name Chesapeake was used by Dall as a general term to include all of the Miocene of the Atlantic and Gulf Coastal Plain.
Dr. Vaughan' has recently made a paleontologic study of the Miocene at Porters Landing, Savannah River, Effingham County, and has correlated the late Miocene here [="Edisto" phase of Sloan, of his section] with the Duplin marl of North Carolina, and considers the older Miocenf? here [= Marks Head of Sloan] the approximate equivalent of the Calvert formation of Maryland.
'Bull. South Carolina Geol. Survey No. 2. ser. 4. p. 273. 'Eighteenth Ann. Rept.. , U. S. Geol. Survey, 1896-1897, pp. 327-34R. Proc. U. S. National Museum, vol. 19. No. llHl, 1896, pp. 303, 304. 'Science, n. s., vol. 31, No. 804, May 27, 1910. pp. 833, 8:l4. According to Doctor Vaughan the "Edisto" of Sloan in the Porters Landing section ls not his "Edisto" of the vicinity of Charleston, but is a much later horizon.

MIOCENE

363

MARKS HEAD MARL
NAME
The }liocene at Porters Landing was differentiated by Sloan' into two phases, which he designated the "Edisto" and Marks Head phases, respectively, correlating the former with the phosphatized Miocene marl on Edisto River, S. C., and applying a new name to the latter. Later, Dr. Yaughan' has shown that the luwer of Sloan's phases, the Marks Head, is approximately synchronous with the Calvert formation of Maryland, and that the upper or "Edisto phase" is contemporaneous with the Duplin marl of North Carolina. The latter is stratigraphically higher than the Edisto marl of South Carolina.
The name Marks Head is derived from :Marks Head, a small ravine one mile northwest of Porters Landing, Savannah River, Screven County, Ga. The Marks Head marl, although corresponding approximately to the Calvert formation, is separated from it geographically by a wide interval, and the different name Marks Head is therefore appropriate.
DEFINITION
Stratigraphic Relations.-The Marks Head marl rests upon the Alum Bluff formation of the Oligocene. The exposures on Savannah River fumish evidence of an erosion unconformity, separating the former from the latter. However, both the physical and faunal evidence seems to show that the time interval represented by this unconformity was relatively short. The formation is overlain unconformably by the Duplin marl. Since the Marks Head marl is of Ejarly Miocene age and the Duplin marl of late Miocene age, the unconformity separating therri is an important one.
Lithologic Characters and Thickness.-The beds of this formation consist of gray or brownish, compact, argillaceous sands, containing large, calcareous nodules, and, in places, of friable, phosphatic sands containing shells. The phosphatic sands are mainly quartz sand with a small amount of phosphate in the form of small, brown and black, smooth or water-worn particles of bones and teeth, disseminated clay, and calcium carbonate in the form of shells and calcareous nodules. (See detailed sections, pp. 371-373.) The maximum observed thickness of this formation is 45 feet, this thickness appearing in some of the sections in the vicinity of Porters Landing on Savannah River.
10p. cit.

:364

GEOLOGY OF THE COASTAL PLAIN

Areal Distribution and Structure.-This formation has been differentiated at and in the vicinity of Porters Landing, Savannah River, Effingham County, Ga. It is doubtless represented in the undifferentiated Miocene occurring in sections above Porters Landing at least as far as Hudsons Ferry, and in the sections between Porters Landing and Sisters Ferry. (See detailed sections, pp. 371a75.)
So far as can be determined from the natural exposures the beds lie almost horizontally, having only a very slight dip southward, probably not more than three or four feet to the mile.
The formation is almost entirely concealed by later sediments, outcrops occurring only in the bluffs of streams; for this reason the beds have had little or no influenct- either upon the topography or upon the character of the soil of the region underlain by them.
Paleontologic Oharacters.-The formation has yielded a relatively small fauna, the collections coming chiefly from localities in the vicinity of Porters Landing, Savannah River. The fossils have been studied by Dr. Vaughan, who furnishes the following annotated list:
Table of fos~ils from the Marks Heal Marl.
Localities' Marks Head, one mile west of north of Porter's Landing.-Earle Sloan and T. W. Vaughan, collectors.
One-half mile above Porter's Landing.-L. W. Stephenson, collector.
One-half mile above Porter's Landing,-T. W. Vaughan, collector.
Porter's Landing, between the Oarolia bed below, and the Ostrea mauricensis ledge above.-T. W. Vaughan, collector.
Porter's Landing, Ostrea mauricensis ledge.-T. W. Vaughan, collector.
Sister's Ferry,-L. W. Stephenson, collector.

MiOCENE

365

NAME

Stratigraphic Range and occurrence

o'd "i;t'l.l

ui r.i

~:i
~

~.,-> >'"...l

_g.9 ;I:

.,::::~;:~

. ;t<-,:j
.:
S...l -+<

Turritella aequistriata Con-

rad

Jericho, N. J

Neverita duplicata var. per-

calosa Conrad

Miocene to re-

. cent

'

Calliostoma aphelium Dall. Jones Wharf and

Calvert Cliffs

Md.

Calliostoma sp.

'

I

X

Yoldia leavis Say Area limula Conrad

i
Miocene and Plh

ocene

! X

Ostrea mauricensis Gabb Eocene, Oligo-,

cene,

lower:

Miocene of Jer-

Pecten marylandicus Wag- icho, N. J.

X

X

ner.

Jones Wharf,

Md., etc.

X

X

Carolia sp. (floridana Dall ?)

X

Mytilus conradinus d'Orb. Throughout the

Astarte yo. (also in the up- Miocene per horizon at Porters) .

.' X

X

Venericardia perplana var.

I

abbreviata Conrad

Miocene of York~

.ruver to Plio-[

cene

. I

Phacoides trisulcatus Con- Oligocene to Plij

rad.

cene

I

I

Phacoides crenulatus (Con- [Miocene of Jeri- 1

rad).

cno, N. J., to!

Duplin horizon,

Phacoides sp..

.. N.C. Jones Wharf, Md.

Cardium laqueatum Conrad. to Duplin hori-

zon, N. c.

I I

Dosinia sp.
Macrocallista sp. Strigilla flexuosa Say

:Ib1ig~c~n~

: t~

I
!
it~-~

Strigilla carnaria (Linn)

cent ..... I
Hitherto only Re-

cent

Donax n. sp.

X

Mactra sp. (hinge of large

sp.)

Spisula n. sp. Corbula n. sp.

.t.

X

Balanus

I

I I

X

I

- -- ~---~

.. :i t> ]0~ o.,; ui

" ~:i
~
>'",_; .oo."S'
"-,:j
- "' ""j

., .s .,a,15 ...,

~~ ...l

j'~> ur -,:j ..
d ;...-
jc3~>

~
t:

.~,.~,=~:i
~H,..;

<~~>t=E~,f-:o.

e
~

-+< '"'

~ iii

X

X

X X

X

X

X

X

X

X

X

X

X

X X

X X

X X X

X

X X

X

X

X

X

----

366

GEOLOGY OF THE COASTAL PLAIN

"Geologic Horizon.-The presence of Carolia in this bed suggests Oligocene, but every other identifiable species may be Miocene, and only three others range downward into the Oligocene; nine species are not known below the Miocene; of these nine, six are confined to the Miocene. The horizon is, therefore, in the Miocene, while the presence of Turritella wquistriata Conrad, Calliostoma aphelium Dall, Ostrea mauricensis Gabb, and Pecten marylandicus Wagner, definitely points to a horizon low in the series."
Economic Geology.-From an economic viewpoint the formation contains little of interest. It contains some phosphatic marls which may prove to be of local value as fertilizers or as fillers for commercial fertilizers.

DUPLIN MARL

NAl\[E.
The name Duplin is derived from Duplin County, N. C. It was proposed as a formation name by Dr. Dall in publications appearing from 1895 to 1903.'''

DEFINITION

Stratigraphic Relations.-The Duplin mal'l re~ts unconformably upon the ~larks Head marl, or, where the latter is absent, upon the Alum Bluff formation of the Oligocene. The former relations ~were observed in the various sections examined at and in the vi-

einity of Porters Landing, Savannah River (pp. 371-373), and the

latter relations are believed to obtain in sections on Altamaha

River, at the bluff at Doctortown, at Buzzards Roost Bluff, and at

Bngs Bluff (pp. 376-377.)

~

The formation is overlain unconformably by deposits referred in this report in part tentatively to the Altamaha formation, and in part to the Pleistocene (terrace deposits).

Lithologic Characters and Thickness.-The formation as exposed on Savannah River is mainly a shell marl, consisting of shells in a matrix of coarse, phosphatic sand; but in places it consists of a fine, gray, or brown, quartz sand, which contains scarcely any fossils or calcareous matter. The formation probably does not reach a thickness of more than 10 or 12 feet.
The Duplin marl on Altamaha River consists of friable, sandy, and pebbly shell-marl, and bluish, compact,- fine-grained, argillaceous
'Proc. Nat. Mus., vol. 18, 1895, pp. 31, 40, 46. 'Eighteenth Ann. Rept., U. S. Geol. Survey, pt. 2, 1898, p. 338. 'Trans. Wagner Free Inst. Sci., Philadelphia. vol. 3, pt. 6, 1903, pp. 1598-1603.

MIOCENE

367

sand which is also fossiliferous. The formation overlies; unconformably, strata of probable Alum Bluff age and is, in turn, over-
n lain by vari-colored sands and clays which probably belong to the
Altamaha (Lafayette formation. The Duplin marl does not reach a thickness of over 12 or 15 feet in natural exposures.
Areal Distribution and Structure.-The formation has been differentiated in the sections at Porters Landing, and at Mount Pleasant Landing, one and one-half miles below Porters Landing on Savarmah River (pp. 371-374). It is doubtless represented in nndiffercn tiated :Miocene beds recognized in bluffs above Porters Landing as far as IIudsons Ferry, and below Porters Landing perhaps as' far as Purisburg, S. C., 23 miles above Savannah. It has also been differentiated at Doctortown, at Buzzards Roost Bluff, and at Bugs Blnff on Altamaha Hiver. The formation probably underlies much of the area, beneath surficial formations, between the occurrences on Altamaha and on Savannah rivers.
The Duplin beds dip to the southward at a very low angle, the inclination probably not E>xceeding three or four feet to the mile.
Except as revealed in occasional stream bluffs the formation is probably concealed over the entire area of its occurrence by surficial deposits, and for this reason has had little or no part in determining the topographic features or the character of the soils of the region.
Paleontologic Characters.-This formation has yielded a fairly large number of species in Georgia, although compared with the collections from the type region in North Carolina the fauna is small. The collections were made chiefly at Porters Landing on Savannah River, but a few species have been identified from Doctortown and from Buzzards Roost Bluff on Altamaha River. Dr. Vaughan furnishes the following annotated list of species identified from the Porters Landing collections:

368

GEOLOGY OF THE COASTAL PLAIN

Table of fossils from upper horizon of the Miocene, Porters Landing> Georgia.

L. W. S.=L. W. Stephenson, collector. T .. W. Y.=T. W. Vaughn, collector. D.=Duplin, N. C.

1

2

IUp;;: L 5w191 s

endiLoJ;; end of Bluff of Bluff

I . .. T.W.V. T.W.V.

Scala sp. a.

X

Scala sp. b

X

Scala sp. c

X

Scala sp. d

X

Scala sp. e Scala sp. f Turritella variabilis Conrad . Turritella duplinensis Gardiner

I

X

I

X

.D. I

X

X

.D. I X

Omphalius exoletus (Conrad) Calliostoma mitchelli (Conrad) .

.D. I X

X

.D.

X

Calliostoma armillatum (T. & H.)

.D.

X

Fissuridea sp. yo .

.D.

X

Cadulus thallus Conrad

.D.

X

X

Nucula proxima Say ..

.D.

X

X

Leda acuta Conrad

.D.

X

X

Glycymeris sp. yo . Area improcera Conrad Area sp. fragment Ostrea disparills Conrad

I

X

:I .D.

X

.D.

X

X X

X

Ostrea sculpturata Conrad

.D.

X

X

Pteria colymbus Bolten

X

Pecten eboreus Conrad

.D.

X

X

X

Pecten jeffersonius Say .

X

X

Pecten jeffersonius var. septenarius Say . . D .

Pecten sp.

X

X

X

Pseudamusium sp.

X

Plicatula marginata Say

.D.

X

X

Anomia simplex d'Orb

.D.

X

X

X

Placunanomia plicata T. & H.

.D.

X

Astarte concentrica Conrad

.D.

X

X

Astarte distans var. fioridana Dall .

X

Astarte undulata Say

.D.

X

Crassinella dupliniana Dall

.D.

X

Venericardia granulata Say

.D.

X

X

X

Venericardia tridentata Say

.D.

X

X

Venericardia perplano Conrad

.D.

X

Phacoides anodonta (Say)

.D.

X

Phacoides radians (Conrad)

.D.

X

X

Phacoides cribarius (Say) Phacoides multilineatus (T. & H.)

:I .D.

X

X

X X

X X

Chione athleta (Conrad)

.D. . I X

X

X

Venus tridacnoides var. rileyi Conrad

.I X

X

X

Venus tridacnoides Lamarck

.D.

X

Transennella caloosana Dall

X

Tellina (Angulus) umbra Dall

.D.

X

Tellina ? sp. Strigilla sp. fragment .
Mulinia congesta (Conrad) Corbula inequalis Say Balanus, probably 2 species

X

I

X

:I .D.

X

.D.

X X X

X X

Crab chela ..

Lunulites

Other Bryozoa, 2 species

Echinoid spines.

. ..

Septastrea

Astrangia ?

X

X

X

X

X

X

X

.I

X X

Boring sponge ?

____I

X

MIOCENE

369

Total number of identified species, 34 (not counting varieties), 30 of which are also at Duplin. The.four species which have not been found there are as follows:
Pteria colymbus Bolten, the previously known range of which was from the Caloosahatchee Pliocene to Recent, or younger than the Duplin horizon.
Astarte. distans var. floridana Dall. Miocene of Jackson Bluff, Fla., approximately the Duplin horizon.
Phacoides multilineatus (T. & H.) Known range from the Miocene of Maysville, S. C., to Recent; from the Duplin horizon to Recent.
Transennella caloosana Dall. Known range from Miocene of Jackson Bluff, Fla., to Pleistocene, from approximately the Duplin horizon to Pleistocene. The bed whence the fossils came is evidently the stratigraphic equiva lent of the Duplin marl of North Carolina.
Economic Geology.-The formation gives but slight promise of yielding products of economic value. It contains some phosphatic
marls which may prove of local value as fertilizers, or as fillers for commercial fertilizers. The terrane may be of importance as a
water-bearing formation since it probably is the source of many of
the flowing wells obtained in Glynn, Mcintosh, and Camden
counties.

UNDIFFERENTIATED MIOCENE

Excepting the exposures in the vicinity of Porters Landing, at Mount Pleasant Landing, and at Sisters Ferry, it has not been possible with the available data to differentiate tho J\1.arks Head and Duplin divisions of the Savannah River sections, though doubtless both formations are represented at least from I-Iudsons Ferry in Screven County to Sisters Ferry in Effingham County. Detailed information concerning these undifferentiated J\liocene beds are given in the chapter on local details, pages 377-378.
Fossils of Miocene age have been recognized in dredgings from Brunswick River at Brunswick, Glynn County, Ga., but they had been mixed by the dredging processes with la1;ge numbers of shells younger than the J\fiocene. Limestone tentatively referred to the Miocene occurs on the Livingston plantation, 18 miles west of Brunswick in Glynn Gounty, and a calcareous sand at Owens Ferry, Satilla River, eight miles west of \Voodbine, Camden County.
It is believed that strata of Miocene age underlie much of the region adjacent to the Atlantic Coast beneath beds of younger age; and it is considered not improbable that such strata may reach a thickness of several hundred feet. However, confirmatory evidence is Jacking.

370

GEOLOGY OF THE COASTAL PLAIN

LOCAL DETAILS

Because of the limited area of the exposures, and as the different subdivisions recognized can not be definitrly identified except at a few of the better exposures, the local details of the :Miocene will be treated together.

SAVANNAH RIVER

Strata of :Miocene age appear in exposures on and near Savannah River at intervals from Hudsons Ferry, Ga., 681j2 ,miles above Savannah, to Purisburg, S. C., 23 miles above Savannah. Sections of a number of bluffs in which :Miocene strata occur, and which are considered stratigraphically important, are given below. Final decisions as to the divisions and the age of some of the beds exposed from Hudsons Landing southward have not yet been made, and the conclusions here presented are only tentative. Some sections of interest in connection with the :Miocene are given in the chapter on the Alum Bluff formation.

Hudsons Ferry.-A section observed one-half mile below the landing, in which 37 feet of undifferentiated :Miocene is recognized, is given in the chapter on the Alum Bluff formation, page 361. The section described below occurs three-quarters of a mile below the landing.

Section at Landing three-quarters of a mile below Hudsons Landing, Screven County.

Pleistocene.

Feet.

8. Loose, incoherent gray. sand . . . .

. 2

Pliocene ?

Altamaha formation ?

7. Mottled gray and red, coarse, clayey sand . . . . . . . 10

6. Interstratified, harsh sand, and fine-grained waxy clay . 10

5. Brown, ocherous, coarse sand; well-rounded pebbles at

base

....................... 5

(Unconformity.)

Miocene.

Duplin marl ?

4. Compact, ash-colored, argillaceous sand . . . . . . . . 10

3. Drab, and brown or yellow, sandy clay containing fossils,

Pecten madisonius, and other fossils poorly preserved . 2

(Unconformity.)

Miocene?

2. Massive-bedded, gray and brown phosphatic sand .

. 25

Oligocene ?

Alum Bluff formation ( ?) .

1. Concealed by creep from upper part of bluff . . . .

. 20

Division No. 3 contains prints of Pecten, poorly preserved leaf impressions, sharks' teeth, and dental plates of fish; at the base a few

MIOCENE

371

well-rounded quartz pebbles appear. From its lithologic appearance and position in the section No. 2 is believed to be the equivalent of division No. 4 of Sloan's Porters Landing section which is subsequently given. Paleontologic evidence to confirm this is lacking.
Similar sections were observed in other bluffs in this vicinity and the Miocene seems to be separated from both the overlying and ~nder lying formations by unconformities, which are marked by lines of small quartz pebbles. These pebbles are generally flat, oval, and discoidal, and are probably of beach origin.

Marks Head.-The following is the section at Marks Head, the type locality of the Marks Head formation, adapted from that given by Sloan!

Marks Head) on the western side of Savannah River) one mile northwest of Porters Landing) near head of Marks Head Run.

6. Surface sands.

5. Thin broken line of hard yellow marl.

Feet.

4. Yellow-brown clayey matrix inclosing soft fossil shells

3. Partly indurated sand mass inclosing some fossil molds

(2and 3 aggregate 14 feet in thickness).. . . . 10

2. Blue-green matrix inclosing many small rounded black

particles, and soft shells (Pecten, Mytilus, Mytilo-

concha, Area, Anomia, etc., etc.). . . . . . . . . .

4

1. Hard, sandy, brown matrix inclosing many soft shells.

Extends below valley line increasing in hardness

with depth . . . . . . . . . . . . . . . . . . . .

1

For a list of the fossils from this locality, see page 365. Porters Landing and Vicinity.-The best exposures of the Miocene occur in the bluffs at Porters Landing, 62 miles above Savannah, and the section is of much stratigraphic importance. It has been studied in detail by Mr. Earle Sloan,' State Geologist of South Carolina. The following section is based upon his descriptions, but the classification of the beds is changed to ~ccord with the conclusions of Dr. Vaughan from a careful study of the fossils.

Section at Porters Landing, 62 miles above Savannah.

Age ?

Feet.

8. White, yellow, and red sands in stratified beds of both

fine and coarse-grained material . . . . . . . . . . 64

7. Thin broken line of vertebrate remains, and small pieces

of phosphate rock . . . . . . . . . . . . . . . . . .

Miocene.

Duplin marl.

6. Ledge of compact, yellowish marl enclosing Pecten ebor-

eus, Ecphora quadricostata, numerous Anomias, etc .

5.9

1Bull. Geol. Survey of South Carolina, series IV, No. 2, p. 274. Bull. Geol. Survey of South Carolina, series IV, No. 2, p. 273.

372

GEOLOGY OF THE COASTAL PLAIN

Marks Head marl. 5. Dun-colored mass of leached marl and indurated sands enclosing many rounded concretions of carbonate of lime encasing variable amounts of sand. Some concretions more than two feet in diameter. The basal portion is a hard concretionary layer (about a half foot thick) formed along a highly irregular surface. Stratum ( 5) appears at same level as the Marks Head marl at its type locality, one mile northwest . . . . . . . . . . 27 4. White sands enclosing a large number of one species of Pecten and numerous shell fragments, Pecten marylandicus Wagner . . . . . .. . . . . . . . . . . . . . . 1.7 3. Fine-grained, laminated shale with sand partings. The median portion appears in the form of silicified concretions. The base includes a line of rounded pebbles . 14
Oligocene. Alum Bluff formation. 2. A much leached marl enclosing Carolina floridana Pectens, sharks teeth, rib of cetaceans, and a large number of small, discoidal, quartz pebbles . . . . . . . . 6 1. Above zero water level appears 0 to 8 feet of a laminated drab shale with arenaceous partings. Enclosing molds of the Lucinidae, and at Hudsons Ferry impressions of the dwarf palmetto . . . . . . . . . . . . . . . . .
Sloan recognized two divisions, the "Edisto" and Marks Head.
In a subsequent study, Vaughan' correlated the upper Miocene
horizon with the Duplin of North Carolina.
The following sections near Porters Landing are by the authors of
this report.

Section 100 yards below Porters Landing.

Pleistocene ?

Feet.

6. Loose, gray sand . . . . . . . . . . . . . . . . . . .

5

Pliocene ?

Altamaha (Lafayette ?) formation ?

5. White, yellow, and red sand

25

Miocene.

Duplin marl. 4. Bed of shell marl; shells in a matrix of coarse, phos-

phatic sand. Small, well-rounded, quartz pebbles at the base, resting unconformably on No. 3, Pecten eboreus,

Pecten jeftersonius, Anomia simplex, Area, Phacoides,

etc . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Marks Head marl. 3. Brown or gray, phosphatic sand with large calcareous nodules, as much as two feet in diameter or length . . 30

2. Drab, or dark greenish, sandy, faintly laminated clay

(no unconformity observed between Nos. 2 and 3.) . . 10

1. Sandy, drab clay, partly silicified, and contains hard,

round, siliceous concretions. Phosphate pebbles, but

not so abundant as in No. 3. Contains Pecten mary-

landicus . . . . .

. .......... . 8

'Science, n. s., vol. 31, No. 804, May. 27. 1910, pp. 833, 834.

MIOOENE

373

As the basal beds o the bluff were under water at the time o making the section, the Alum Bluff ormation was not studied at this locality.
An exposure appears about three-quarters o a mile northwest 0 Porters Landing.

Section one-half to three-quarters of a mile northwest of Porters Landing.

Age ?

Feet

5. Upper beds concealed . . . . . . . . . . . . . . . .

?

Miocene.

Marks Head marl.

4. Brownish quartz sand containing at the base a mass of

shells and phosphatic sand, Ostrea mauricensis . . . 6

3. Compact, gray, argillaceous and calcareous sand, phos-

phatic . . . . . . . . . . . . . . . . . . . . . . . . 18

2. White and brown sand, shells in white, phosphatic sand

very abundant about the middle of the J::ed; fossils,

Oarolia fioridana (?), Mytilus conradinus, Pecten

marylandicus, Anomia, Area, etc. . . . . . . .

15

1. "Concealed by talus to the level of the swamp . .

6

For list o fossils rom this locality see page 366.

Section about 200 yards above Porters Landing.

Pliocene (?)

Feet

Altamaha formation ?

10. Coarse, variegated sand with line of small, quartz peb-

bles at base . .

25

Miocene.

Duplin marl.

9. Fine, brown sand . . . . . . . . . . . . . . . . . . . 4

8. Friable marl; shells in a matrix of coarse gray, phos-

phatic sand. Contains large, ribbed Pecten, Anomia

1 Area, etc. A few scattered pebbles at base . . . .

2

Marks Head marl.

7. Brown and ash-colored, compact, argillaceous sand .

6. Compact sand; large, calcareo-phosphatic nodules . . .

5. Calcareous ledge containing Ostrea mauricensis, 20

30

feet above the river level . . . . . . . . . . . . . .

4. Poorly exposed, probably sand, (about 4 feet) . . . . .

3. Friable marl, shells in a matrix of gray sand, Ostrea

mauricensis, Pecten marylandicus . . . . . . . . . . 4

2. B!'ownish, compact, sandy laminated clay, partly silicified 7

1. Greenish, sandy clay . . . . . . . . . . . . . . . . . . 4

Mount Pleasant Landing.-At Mount Pleasant Landing, one and one-hal miles 'below Porters Landing, the Duplin marl is 40 feet above the river, and consists o eight feet o friable, highly calcareous shell marl overlain by coarse, brown sand which reaches a thickness o 10 feet. The shell marl here in places approaches somewhat the lithologic character o coquina, or friable shells in a

374

GEOLOGY OF THE COASTAL PLAIN

sand matrix, and is similar to some of that observed at Doctortown on Altamaha River. Beneath this upper bed is brown, phosphatic sand, similar to that at P6rters Landing.

Section at M aunt Pleasant Landing, one and one-half miles below Porters Landing.

Age ?

Feet.

1. Sand, and white, tough, waxy, laminated clay with sand

partings. Stratum poorly exposed

20

Miocene ?

2. Coarse, brown sand . . . . . . . . . . . . . . . . . . 10

Miocene.

Duplin marl.

3. Friable marl and limestone, contains shells and casts of

shells, Pecten, etc. . . . . . . . . .

7

Marks Heud marl.

4. Brownish, phosphatic sand . . . . . . . . . . . . . . . 25

5. Greenish, sandy clay, not well exposed . . . . . . . . . 20

At the Seaboard Air Line Railway bridge, three miles north of

Clyo, there is 30 feet of fine-grained, white and yellow, sugar-like

sand, the basal portion of which contains fine, brown, phosphatic

grains. While this stratum contains no fossils, its lithologic char-

acter and geologic position suggest that it is of Miocene age. The

two Miocene divisions (Duplin and Mwrks Head) can not be dis-

tinguished. It is overlain unconformably hy li'l feet of strata re-

ferred tentatively to the Altamaha (Lafayette?) formation; the

latter formation appears to increase in thickness westward from the

bluff.



Sisters Ferry.-At Sisters Ferry, Ga., 47 miles above Savannah, and two miles east of Clyo, there is a good exposure of Miocene strata. The beds consist of greenish or gray, very sandy, laminated clay in the lower part of the bluff, and of crossbedded, red and white sands in the upper part.

Section at Sisters Ferry, Savannah River, Effingham County.

Pleistocene.

Feet. ln.

11. Thin covering of gray sand at the top of the bluff.

Pliocene ?

Altmaha formation ?

10. Mottled red and yellow sand with some thin clay

layers . . . . . . . . . . . , . . . . . . . . . 20

Miocene ? (Undifferentiated.)

9. Coarse, crossbedded, yellow, red, and white sand . . 20

8. Poorly exposed . . . . . . . . . . . . . . . . . . 10

7. Drab, laminated clay, contains hard, sandy, calca-

reous nodules, covered with a crust of fibrous

calcite, . . . . . .

7

6. Hard, silicified clay . . . . . . . . . . . . . . . . 0 8

MIOCENE

375

5. Drab clay . . . . . . . . . . . .

0 3

4. HaJd, silicified, clay . . . . . . .

0 3

3. Laminated, gray, very sandy clay

2 6

2. Hard, silicified clay . . . . . . .

2

Miocene.

Marks Head marl.

1. Very sandy clay, contains some black phosphatic

particles . . . . . . . . . . . . . . . . . . . 3

The only :fossil which could be identified here was a Pecten marylandicus, which occurs near the base o:f the bluff.
About one-hal: mile below the :ferry the dark-colored clays o:f the Miocene appear 25 :feet above the level o:f the river. Southward :from Sisters Ferry the river flows through low Pleistocene plains, and the bluffs along the river do not exceed 30 or 40 :feet in height; along this stretch o:f the river there are :few localities where satisfactory studies o:f the geological :formations can be made.

Frying Pan Landing.-At Frying Pan Landing, eight miles below Sisters Ferry, greenish, ~andy clay, similar in appearance to that at
Sisters Ferry, occurs in the lower eight :feet o:f the bluff.

Section at Frying Pan Landing.

Feet

4. Loose, gray sand . . . . . . . . . . . . . . . .

4

3. Red, clayey sand . . . . . . . . . . . . . . . .

. 10

2. Brown and white, unconsolidated, rather pure, quartz

sand . . . . . . . . . . . . . . . . . . . . . . . . 8

1. Gray and greenish, sandy clay . . . . . . . . . . . . . 8

There are no determinable :fossils and the divisions arc made 011 the basis o:f lithology and geologic position. No. 4 may be safely considered Pleistocene. No means are at hand :for definitely determining the age o:f division No. 3, but it is probably Pleistocene. No. 2. is probably Miocene, since the sandy clay of No. 1 is very similar lithologically to the Miocene at Sisters Ferry and Porters Landing. A similar succession o:f beds continues to Purisburg, S. C.

Ebenezer Landing.-At Ebenezer Landing, 34 miles above Savannah, beds corresponding in position to the Frying Pan Landing beds, rise about 18 :feet above the river. The lower beds here are tentatively referred to the Miocene. They consist o:f brownish or yellow, compact, sandy clays, which contain poor prints and casts o:f :fossils, and white and brownish, fine quartz sand.

Purisburg.-At Purisburg, S. C., 23 miles above Savannah, there is a bluff about 10 :feet high, which exposes Pleistocene and older :formations.

376

GEOLOGY OF THE COASTAL PLAIN

Section at Purisburg, 23 miles above Savannah.

Feet In.

Pleistocene.

6. Red, sandy clay, containing small pebbles, color due

to weathering , . . . . . . . . . .

1

5. Drab or white, laminated clay . . . .

3

4. Line of coarse, quartz pebbles . . . .

0 3

Miocene?

3. Gray or pale green, argillaceous sand

3 6

2. Thin line of quartz pebbles . . . . . .

0 3

(Unconformity)

1. Gray or pale green, argillaceous sand

3

Below Purisburg only Pleistocene deposits are exposed.

ALTAJ\!AHA RIVER
Bugs Bluff and Buzzards Roost Bluff.-In descending Altamaha River the first exposure in which Miocene strata have been certainly recognized is at Bugs Bluff, two and one-half miles above Doctortown. Except that it yields no fossils the section is essentially like that at Buzzards Roost Bluff, two miles (by the river) above Doctortown. The Buzzards Roost exposure is described in detail as follows:

Section at Buzzards Roost Bluff, two miles above Doctortown.

Feet In.

7. Gray sand covering upper slope . . . . . . . . . . 2

Pliocene ?

Altamaha formation ?

6. Mottled, clayey sand . . . . . . . . . . . . . . . 10

5. White, crossbedded, coarse sand, pebbly at the base . 28

(Probable unconformity)

Miocene

Duplin marl.

4. Yellow and white, very sandy clay, pebbly in upper

part, faintly laminated . . . . . . . . .

5

3. Blue, almost black, silty clay . . . . . . . .

6

2. Shell and pebble conglomerate, contains Pecten

eboreus, Mytilus conradinus . . . .

1 6

(Unconformity)

Oligocene ?

Alum Bluff formation ?

1. Bluish gray, massive, compact, clayey sand

10

Layer No. 2 is made up of well-rounded, quartz pebbles, coarse sand and shells. The whole is in places consolidated into a conglomerate, calcium carbonate forming the cement. Large fragments of water-worn, silicified wood also occur. The horizon is the same as that at Doctortown (Duplin horizon). The remainder of the section bears.no fossils and the divisions are made upon the basis of physical differences and relations. The total thickness of the Miocene is 12 feet. It is separated from the underlying formations by an erosion

GEOLOGY OF THE COASTAL PLAIN OF GEORGIA

PLATE XXVI.

B. CHARLTON FORMATION. T. ~~ARY RIVER. (FLO RIDA SIDE) STOKES FERRY. 11 MILES OUT H OF T. GEORGE. CHARLTO~ COUNTY, GA.

MIOCENE

377

.unconformity, and probably also from the overlying formation by an unconformity.

Doctortown.-At Doctortown, Wayne County, the bluff of Altamaha River is 40 feet high, and near the base of the bluff beds of Duplin marl are exposed. The following is a section of the bluff at the south end of the Atlantic Coast Line Railroad bridge.

Section of Bluff at south end of Atlantic Coast Line Railroad Bridge.

Feet

Pliocene ?

Altamaha (Lafayette ?) formation ?

6. Yellow and mottled, argillaceous sand . . . . . . . . . 10

5. White and yellow, crossbedded sand containing thin

layers of small, quartz pebbles . . . . . . . . . . . 10

4. Red and yellow, stratified sand containing thin clay

laminae

. . . . . . . . . . . . . . . . . . . . . 10

(Probable unconformity)

Miocene.

Duplin marl.

3. Calcareous, fossilliferous sand, or sandy, friable marl . 1

2. Bluish sand containing Pecten eboreus, Mactra congesta,

etc. . . . . . . . . . . . . . . . . . . . . . . . . . 4

(Probable unconformity)

Oligocene ?

Alum Bluff formation ?

1. Coarse, bluish or greenish, compact, clayey sand to wa-

ter's edge . . . . . . . . . . . . . . . . . . . . . 7

The relations between layers Nos. 3 and 4 could not be determined with exactness. Layers Nos. 2 and 3 are Miocene. No. 5 is considered Oligocene, and the upper part of the bluff'is referable either to the Pliocene ( ?) (Altamaha formation) or to the Pleistocene.

Below Doctortown there are no known exposures of Miocene
strata, although beds at the bases of Upper and Lower Sansavilla
Bluffs, 27 and 28V2 miles, respectively, below Doctortown, may belong to this series.

GLYNN COUNTY

Brunswick.-At the southern limits of the city at the Atlanta, Birmingham, and Atlantic Railroad terminals, a large amount of shells and rocks have been dredged 'from Brunswick River. A study of the dredged material leads to the conclusion that the :1fiocene underlies this region and is concealed by a small thickness of later formations. The material thrown from the dredge consists of shel-ls, fragments of bones and teeth, sand and quartz pebbles, compact, sandy marl or shells imbedded in a phosphatic sand matrix, argillaceous limestone, and hard clay.

378

GEOLOGY OF THE COASTAL PLAIN

A study of the fossils was made by Dr. Vaughan and they wera found to range from Miocene to Recent. The dredge probably cut through a thin covering of Recent and Pleistocene deposits into. the Miocene. Dr. Vaughan furnishes the following list of fossils collected from the dredgings :

List of fossils dredged from Brunswick River, Brunswick.

Septastrea crassa (Holmes).
Terebra dislocata Say. Conus sp. Young. Drillia abundans Conrad. Oliva Iiterata Say. Olivella mutica Say. Marginella contracta Conrad. Fulgur carcia Linn. Ecphora quadricostata Say. Nassa vibex Say. Ilyanassa obsoleta Say. Nassa acuta Say. Columbella avara Say var. Astyris lunata Say: Turritella variabilis Conrad. Turritella plebeia Say? Crepidula fornicata Say. Neverita duplicata Say. Solarium granulatum Lam. Fissuridea carolinensis Conrad. Dentalium caroll'1ense Conrad. Glycymeris parilis Conrad. Glycymeris subovatus Conrad. . Barbatia adams! Shuttlew. Area lienosa Say.
Area plicatura Conrad. Area transversa Say. Area incongrua Say. Area limula Conrad. Ostrra aisparilis Conrad. Ostrea virginica Gmelin, P. & R.

Pecten jeffersonius Say. Pecten septenarius Say. Pecten madisonius Say. Pecten n. sp. '! Astarte concentrica Conrad. Astarte distans var. floridana Dall. Astarte undulata Say var.
Astarte undulata var. vaginulata Say. Astarte <'Uneuormis Conrad. Crassatellites undulatus Say. Crassatellites sp. t.a:aiainera arata Conrad. Venericardia granulata Say. Echinocnama arcinella Linn. Phacoides anodontus (Say). Phacoides radians (Conrad). Phacoides multineatus (Tuomey &
Holmes). Phacoirle1 amiantus Dall, P. & R. Diplodonta acclinis Conrad. Cardium robustum Solander, R. & R. Chione cancellata Linn. Chione alveata Conrad. IJuione aff. cortinaria Rogers. Don ax.
MJ.linia congesca Conrad. Mulinia congesta var. contracta Con
rad.
Mulinia cone:esta var. elongata Dall. Rangia clathrodon Conrad. Corbula inaequalis Say.

"Geologic H orizons.-At least two mixed, most of the species are Miocene, those marked P. and R. are Pliocene to Recent, and not known from the Jl.fiocene; all of the others may be Miocene, and many are only in the Jl.fiocene. The dredge has cnt through what is probably Pleistocene or Recent into Miocene strata."

Livingston Plantation.-This locality is 18 miles west of Brunswick. The exposure is in the bed of a small creek and can be seen only at low tide.

Section at Livingston Plantation.

Recent. 3. Marsh mud . . . . . . . . . . . . . . . . . . .

Feet 2

PLIOOENE

379

Pleistocene.

2. Greenish gray, argillaceous sand with some smoothly-

rounded quartz pebbles. Bones and teeth in the lower

part . . . . . . . . . . . . . . . . . . . . . . . . . 3

(Unconformity)

Miocene.

1. Yellow, argillaceous limestone . . .

2

A piece of coarse sandstone loosely cemented by lime, containing a Pecten) was obtained at this locality by Prof. McCallie.
The age of the beds has not been proven by paleontologic evidence. Layers Nos. 2 and 3 should probably be referred to the Pleistocene. Layer No. 1 is tentatively referred to the Miocene; however, this rock is similar lithologically to limestones of probable Pliocene age exposed at Burnt Fort on Satilla River, and near Folkston on St. Marys River, and future investigations may prove its Pliocene age.

CAMDEN COUNTY

Owens Ferry.-At this locality, eight miles west of Woodbine, a compact sand and calcareous sandstone is exposed in the bed of Satilla River at low tide. This rock contains fossils, but none are very \vell preserved. It is overlain by bluish, coarse-grained, clayey sand, while the upper part of the bluff is Pleistocene sand and clay. The following fossils from this locality have been identified by Dr. Vaughan:

Fossils from Owens Ferry.

Pecten, probably madisonius, Carditamera arata, Cardium sp.

PLIOCENE
The existence of strata of Pliocene age in Georgia has not been definitely proven. However, certain deposits have been referred with greater or less degrees of confidence to this period. The socalled Lafayette formation of the Atlantic and Gulf Coastal Plain has for many years been regarded as of probable Pliocene age. A summary of the events leading up to the adoption of the name has been given by McGee.1 In a recent contribution E. \V. Berry2 has shown that the name Lafayette, as applied to a surficial formation in the Atlantic and Gulf Coastal Plai~ by McGee and others, is a misnomer, the beds exposed at the type locality in Lafayette CQunty, Miss., being in fact of Eocene age and referable to the Wilcox formation of that series. However; a surficial formation consisting of
1Twelftb Ann. Rept., U. S. Geol. Survey, pt. 1, 1892, pp. 498-502. Journal of Geology, vol. 19, 1911, pp. 249-256.

380

GEOLOGY OF THE COASTAL PLAIN

sands and heavy beds of gravels r~sting unconformably upon Cretac~ous and Eocene strata, to which the name was intended to apply, is extensively developed in certain parts of the northern embayment region, especially in Tennessee and Kentucky.
The so-called Lafayette formation is represented by McGee as covering the whole Coastal Plain of Georgia. Beds considered referable to this formation have been described at numerous localities in Georgia by different investigators, but on the following pages it will be shown that, assuming the formation to be of Pliocene age, many of these correlations were erroneous. Frequently the beds so referred have been found to belong to Cretaceous, Eocene, or Oligocene formations, or are the weathered, residual products of these formations. Terrace deposits -which are clearly of Pleistocene age have also been referred to this formation.
The Altamaha (Lafayette?) formation, a widespread but relatively thin series of sands and clays covering much of central and southern Georgia, is tentatively referred to the Pliocene. Doubtless a part of the strata included in the Altamaha terrane is contemporaneous with the so-called Lafayette formation. However, the inadequacy of our knowledge of the age and stratigraphic relations of the Altamaha deposits is conceded. The possibility is also admitted that the beds here included in this formation may prove to be a complex embracing strata of all ages from the Oligocene to the Pleistocene.
Certain fossiliferous strata exposed on Satilla and St. Marys rivers have, on paleontologic evidence, been considered as probably of Pliocene age. The beds appearing on Satilla River will be described in the chapter on the Altamaha (Lafayette ?) formation, since it is believed they are synchronous with at least a part of that formation. The exposures on St. Marys River will be described nndor tho name Charlton formation.
On following pages the literature relating to Pliocene or supposed Pliocene deposits in Georgia is reviewed.

HISTORICAL REVIEW
In 1884 Dr. R. H. Loughridge' described beds which he considered of Pliocene age, as follows:

The Savannah region along the coast, which occupies the first terrace at an elevation of from 10 to 15 feet above tide-water, is assigned to the PliO<~ene formation. Marls or shell beds of this age are found on the Savannah River near the Effingham and Chatham County lines. On Satilla River a white marl bed outcrops at Burnt Fort, the head of tidewater, which is
1'T'enth Census, vol. 6, part II, 1884, p. 16.

PLIOCENE

381

mostly devoid of fossils. In the sand and clay beds of the coast region in
Glynn, Chatham, and other counties have been dug up the remains of gigantic quadrupeds, such as the mastodon, and along its borders are buried stumps of cypress and other trees still standing upright.

Loughridge referred strata both older and younger than the Pliocene to this period. The "marl or shell beds" on Savannah River are in part o:f Miocene and perhaps in part o:f Oligocene age. (See pp. 370-376 o:f this report.) The sands and clays o:f the coast region which bear remains o:f quadrupeds and contain buried tree stumps are believed to be o:f Pleistocene age. No :fossils have been identified from Burnt Fort, but the beds are regarded as the equivalent o:f the fossiliferous beds on St. Marys River (Charlton :formation) which Dr. Vaughan regards as probably of Pliocene age.
In 1891 W J McGee1 described the deposits in Georgia which he regarded as referable to the Lafayette formation. The following are quotations :from his report with comments by the writers:

"The exposures on both sides of the Chattahoochee River at Columbus

are specially noteworthy, not only by reason of the clear display of struc-

tural and textural features, but because the terracing which characterizes

the formation at many localities is here particularly well displayed. Colum-

bus is built on a terrace a mile broad, thinly veneered with "second bot-

tom" (Columbia) loam near the river, but consisting generally of the orange-

red loam of the Lafayette, massive above, mottled 8 to 15 feet below the

surface, and more or less definitely bedded below; Phoenix, or Lively, on the

opposite side of the river, is built on a higher terrace of bronze-tinted

loam, here containing moderately abundant disseminated pebbles, and

the many excellent exposures in the railway and street cuttings well display
the stratification of its lower portion... * .. * .. (p. 478.)

"On examining the materials composing the formatio:1 at Columbus,

certain new feamres apppear. As usu: 1, -the upper part of the deposit is

orange tinted loam, mass1ve, rock-like, undergoing suverficial cementation on

weathering, and flecked or streaked with white; but the color is lighter

than in Mississippi, the proportion of sand is smaller, the sand grains are

coarser and more angular, and the flecks and streaks of white are no longer

of siliceous clay or pt:lverulent amorphous silica but of kaolinic clay or

kaolin. The lower portion of the formation displays a bedding as distinct

as the stratification of Mississippi, but the bedding is simply a ser aration

of the loam into heavy, rock-like ledges parted by leaves of clay, sa 1d, and

gravel, quite unlike the inter-stratification (with occasional cross-.amina-

tion) of sands and clays in the western part of the terrace; w, too, the

materials of the intercalated clay leaves are changed, instead of the silice-

ous pottery clays of Mississippi and Tennessee they are chiefly a kaolin-like

material, with occasional quartz crystals and mica scales included; and

the pebbles are no longer 01 chert, as in Mississippi and Tennessee, or even

the mixture of cherts and siliceous dolomites found on Tuscaloosa River,

but mainly of granular quartz with occasional well worn bits of quartzite.

(p. 478.)

'

"The exposed thickness of the formation about Columbus is generally

10 to 30 feet; and the combined exposures indicate that while the thickness

is exceedingly variable it probably reaches a maximum of 50 or 70 fP<:JL
* * * * (p, 478.)

'Twelfth Ann. RPpt .. L- ;;. GPol. Survey, pt. J, 18D1, pp. 4i8-4QO.

382

GEOLOGY OF THE COASTAL PLAIN

"Along the Chattahoochee River about Columbus, and southward nearly or quite to the confluence of the Flint, the Lafayette deposits are not concealed by the newer Columbia formation save along the rivers, which are all flanked by the "Second bottom" loams characteristic of the rivers of
the eastern Gulf slope * * * (p. 479.)
"In the vicinity of Columbus, particularly on Mill Creek, between Phoenix and Girard, the Lafayette rest~;, either with or without marked unconformity, on the Potomac (Tuscaloosa) arkosic sand and clay; the materials of the terrace east of the river and north of Columbus generally lie on the eroded surface of the Piedmont gneiss; within 2 or 3 miles south of Columbus the Lafayette rests unconformably (though sometimes the unconformity is inconspicuous or even imperceptible) on the sands of the Eutaw; while still farther southward it reposes with like unconformity successively on the Ripley, the various divisions of the argillaceous Eocene (Hilgard's Lignitic), the White limestone of Smith and Johnson, and Miocene limestones. About Columbus the materials of the basal part of the Columbia, of the Lafayette, of the Potomac (Tuscaloosa), and sometimes of the Eutaw, contains certain common elements and sometimes approximate in composition so closely that they may be discriminated only by structural characteristics; and in some of the most conspicuous exposures near the mouth of the Mill Creek the Lafayette and the Potomac (Tuscaloosa) have not been certainly discriminated.:' ( pp. 479-480.)
The deposits on the plains bordering Chattahoochee River in the
vicinity of Columbus, and extending dow'll the valley from Colum-
bus, are Pleistocene terrace sediments which rest upon Cretaceous,
Eocene, and Oligocene strata.
"The lower portion of Macon is bullt on a "second bottom" plain, but the residence part of the city stands on the amphitheater-like slopes semicircling the terrace occupied by the low-lying business portion; and in every street and country roadway, in every excavation on railways entering the city from the west, northwest, and even from the southeast, the orangetinted loams are well displayed, always with the prevailing color and frequently with characteristic structure; so the roads, streets, railways, ancl hill slopes of the most of Macon gleam red against the dark green background of the pine-clad hills. Here as elsewhere the material is a loam, containing a sufficient element of clay to produce considerable coherence, orange red or or sometimes brick-red above, mottled orange yellow at greater depths. Here, as elsewhere, the formation is characterized by irregular stratification and rather obscure crossbedding in its lower portion,. the structure lines being marked sometimes by ferruginous crusts and sometimes by lines of pebbles or gravel grains, but more frequently by sheets of white plastic clay, sometimes continuous, sometimes in layers of distinct pellets. Here, as elsewhere, the upper part of the deposit is massive, and diplays in an 'minently satisfactory manner the distinctive semiglazing or case-hardening by which tlre formation is generally characterized. Here, as elsewhere, the deposit is frequently pebbly, the pebbles being either arranged in lines of stratification or accumulated in pockets and in beds, sometimes assorted by size, and as usual the pebbles are commonly disseminated above and commonly bedded below; and here, as at Columbus, the pebbles consist predominantly of mederately well rounded and subangular fragments of quartzite and quartz, ranging from 3 inches in diameter downward, and there are in addition a few granitoid fragments. (p. 480.)
"The relations of the Lafayette formation to the Columbia "second bottom'' are not well displayed, but the relations to the Potomac are admirably displayed in many exposures. The eminence in the western part of the -city known as Primrose Hill is a cusp of Potomac arkose only veneered with

PLIOCENE

383

the Lafayette, and the street cuttings and gullies by which it is laid open .along many lines display the two formations in contact, sometimes conforniable in structure and concordant in materials to such an extent that they may not be demarked, but elsewhere strongly unconformable in structure and discordant in composition. Precisely similar relations are displayed in the half dozen or more excellent exposures on the Georgia Southern Railway in the western part of the city, in some of which the formations are quite distinct, while in others they intergrade." (pp. 480-481.)

The physiographic features at Macon are: (1) terrace or "swamp" 1.5 to 20 feet ahove the level of Ocmulgee River; (2) terrace plain 40 to 50 feet above the first plain; (3) upland plain 100 to 125 feet aboye the second terrace plain. J\.IcGee does not describe this terracing in detail, hut it is inferred that he considered the Lafayette as occurring on aU three ]jlains. Both the second terrace

and the higher land have gravel and red loam deposits spread over them, but these deposits are evidently of different ages since they are separated by a vertical interval of as much as 100 feet, and the deposits do not appear to form a continuous mantle over the escarpment between the two plains. Those on the lower two plains are Pleistocene terrace deposits. The red loam deposits on the high land west and south of l\facon are lithologically similar to the Eocene

strata capping the hills on the east side of Ocmulgee River, and it

is believed that they correspond to them. "Over the divide between the Ocmulgee and the Oconee the

Lafayette appears in many exposures." (p. 481.) No localities where the exposures appear are mentioned. There are in places deposits of red sand unconformably overlying the Cretaceous which might be mistaken for surficial deposits but which have been shown by their contained fossils to be of Eocene age. At other places there are similar sands which do not contain fossils, but these can usually

be traced into fossil-bearing Eocene beds. It is believed, therefore,

that McGee has mistaken the red Eocene sands for the Lafaytte for-

mation.



The formation is mentioned as occurring in the vicinity of Millen

(p. 481), but no particular locality is described. In this report these deposits are considered referable to the Altamaha formation.

"* * * But on returning to the fall line the normal fall-line fea-
tures recur, as in the fine exposure near Green's Cut (10 miles south of Augusta) where the usual aspect of the massive loam is well displayed. At this point the deposit is exceptionally pebbly, to the extent, indeed, that it has been largely worked as gravel for railway ballast, the pebbles ranging from 2 inches down, the most abundant dimensions being three-fourths to one and one-quarter inches; the materials are predominantly quartz and quartzite, with no chert, the prevailing form being fairly well rounded, and the pebbles are accumul~ted in layers, sometimes discontinuous, in which it
is occasionally cross-bedded, though even in these layers the gravel is nowhere clean, the pebbles being simply disseminated closely throughout a

384

GEOLOGY OF THE COASTAL PLAIN

matrix of loam just as the finer sand grains are disseminated through a clay matrix in the loamy parts of the formation." (p. 481.)
At Greens Out on the Central of Georgia Railway, 27 miles south of Augusta (probably the locality referred to in the above description), is a deposit of mottled sands and gravels overlying the Barnwell sand of the Claiborne group. These have much the aspect of the Altamaha formation which appears to the southward and they are believed to be referable to it.
"In central Georgia the Lafayette forms the surface on the Ocmulgee and the Oconee rivers, save where the "second bottoms" overlap it; but farther eastward, on the Ugechee as well as toward Savannah, the distinctive "second bottoms" proper disappear, and the coast-sand mantle stretching up from the seashore, and along the Savannah finally overlaps the Lafayette and extends upon the Piedmont gneiss, from which the orangetinted formation has been removed, if it was ever deposited." (p. 481.)
Just what is meant by "second bottoms" is not clear, but here, a8 elsewhere in Georgia, the materials occupying definite plains bor dering the rivers are considered Pleistocene terrace deposits.
"In southwestern Georgia, e. g., about Thomasville, the characteristic orange tinted or brick-red loams (in this direction the colors strengthen) are not concealed by the coastal sands of the Columbia epoch, except about the lower levels; but in southeastern Georgia there is a more or less continuous mantle of these sands, by which the Lafayette is commonly buried from sight. In passing southward from Thomasville the features of this formation and its relations to the Columbia are well displayed." (p. 482.)
The so-called Lafayette materials referred to in the preceding quotation are in this report considered referable to the Altamaha formation; they oYerlie the Alu'm Bluff formation (Oligocene).
"The Lafayette is well exposed on the southern bank of St. Mary's River, near Traders Hill. Here the upper part is orange brown or drab and massive for a few feet, but it quickly becomes regularly bedded, the heavier layers of brown or gray clayey loam separated by leaves of gray silt and brown or drab sand. It is again displayed in many railway cuttings about Waycross, where the upper massive member is better developed yet decidedly less distinctly massive, orange-tinted, and casehardened than in central Georgia, while the lower part is always stratified. It is revealed to a depth of 40 feet or more at Doctortown in a railway cutting through a natural bluff overlooking the Altamaha; here the upper member is ill developed or absent and the mass is stratified throughout, consisting of alternations of brown loam and white silt above and in the lower part of the exposure these become, respectively, blue or gray clay and light colored sand. Still farther northward the formation approaches within 10 miles of the sea islands and inlets in the Cherokee Ridge on the southern side of the Savannah. The upper massive member is fairly displayed here, though orange yellow rather than of the characteristic color, while the lower portion consists of stratified sand with fine gravel disposed in sheets." (p. 484.)
A detailed section at the Atlantic Coast Line bridge near Folkston, probably the Traders Hill locality, is given on page 398 of

/

PLIOCENE

385

this report, and the stratigraphic relations of the beds discussed.

The strata above the Charlton formation (probably Pliocene) are

considered of probable Pleistocene age. The materials exposed near

Waycross are, in this report, considered a part of the Altamaha for-

mation. The beds above the fossiliferous Miocene marl at Doctor-

town are tentatively referred to the Altamaha formation, although

they may be Pleistocene terrace deposits.



"Superb exposures of the Lafayette, displaying the usual fall line features, occur on Savannah River about Augusta. The characters and structural relations here represent those exemplified at Columbus and Macon, save that the "second bottom" phase of the Columbia is replaced by a series of sandy terraces running up into the prevailing coastal sands." (p. 484.)

It is probable that both Pleistocene and Eocene deposits at Augusta
have been mistaken for the Lafayette. The Pleistocene beds are de-
scribed on page 433 of this report. Sunhill and Munnerlyn are mentioned by McGee as localities
where the Lafayette may be observed. The materials at both lo-
calities appear to be identical in character with those of the Alta-
maha formation, which is well exposed to the southward of these
localities.
In 1891 J. W. Spencer' also gave detailed descriptions of sup-
posed occurrences of Lafayette strata in Georgia. The following are
quotations from his report, with comments by the writers:
"At Rich Hill, about six miles southeast of Knoxville, the same red loam forms a capping at an elevation of 835 ( ?) feet; and near by, gravel is seen on the hills at fifty feet below. At both these localities, the loam forms a capping for both the surface and the sides of the hills, where the underlying formations were incised by former eroding streams. This condition is common to the formation, as it forms a sheet alike over the ancient hills ant'i greater valleys. The base of this loam, especially in the vicinity of the greater rivers, passes into a well marked bed of rounded quartz gravel, sometimes three inches in length. Such gravel is seen upon the hills between Knoxville and the Flint River, at elevations of 130 feet above its modern high water. South of Knoxville the red loamy surface is replaced by a belt of loose gray sand."

The red loam capping Rich Hill is probably of Eocene age. The
materials at lower levels in this vicinity are in part residual sands
and in part Pleistocene terrace deposits.
"The country south of this point is, commonly speaking, a high plain somewhat incised by streams. The surface is generally composed of the orange loam, which varies in thickness from zero to 20 feet, as shown in the railroad cuts south of Gaillard's.
"At Fort Valley, this red loam or clay reaches a depth of 2 feet, as shown in the artesian well. About three miles south of Fort Valley, there is an excellent exposure in the railroad cut on the road to Americus.

'First Report of Progress of the Geological Survey of Georgia, 1891, pp. 60-72.

386

GEOLOGY OF THE COASTAL PLAIN

Feet "1. Deep colored red loam or hard sandy clay, with rounded
gravel in the lower two feet, resting upon an eroded surface . . . . . . . . . . . . . . . . . . . . . . . . . G-10 2. White and red mottled clay with surface eroded . . . 7- 3 3. Thin laminated sand with clay partings . . . . . . . 2 4. Laminated sand in colors from black to white exposed . 10

"No. 1 represents our Lafayette deposit, and I am inclined to place even

the lower members as belonging to an earlier episode of that period.

"In a neighboring washout, the red loam has a thickness of ten feet,

underlaid by beds of whitish clay from 4 inches to 2 feet thick, intercalated

with sand beds. Some of these sands are deep red, and others gray or

white; beneath the whole are white sands. This section reaches a total

thickness of about 25 feet.

"From Fort Valley southward, the level plateau is covered with the

red loam of argillaceous texture. West of Winchester, sections of this

superficial material are well shown, where about eight feet of orange clayey

sand rests upon laminated sands in white and colored bands. Upon the

higher plateau, above Montezuma, the red loams prevail; but in descending

to the Flint valley, the underlying gray sands form the surface soils. This

is true over the lower country about Montezuma, and, indeed, for many

miles in the direction of Americus. But the higher hills are everywhere

capped with the orange loam.

"Along Flint River, many sections of the Lafayette loam are seen form-

ing the bottom lands. The best section, in its relation to other rocks, is

shown about two miles south of the great bend, in the river in closest prox-

imity to Everett station. That section is here given.

Feet

"1. Orange loam or sandy clay . . . . . . . .

8

2. Light bluish clay with irregular joints stained red

6

3. Orange and gray clayey sand, unconformable above and

below .

. . . . . . . . . . . . . . . . . . 5-9

4. Coarse light bluish clay, unconformable above and

below . . . . . . . . . . . . . . . . . . . ... 3

5. Orange-colored quartz gravel, unconformable above . 10

6. Coarse white sand cemented with clay, exposed . . . 4

"The upper three members and the fourth member represent. two distinct episodes, as shown by the unconformity. At the ferry, between Winchester and Garden Valley, the mantle of orange loam Is well developed, reaching from near the river to the surface of the country 210 feet above it, this occupying alike the hill and the old valley. Here, the deposit is of a more sandy character than adjacent to Fort Valley, and the lower beds are cemented into occasional blocks of ferruginous sandstone."

The deep red materials forming the upland surface at Fort Valley and southward to the vicinity of Montezuma are in this report considered of Eocene age, and probably referable to the Claiborne group. The materials on the low plains bordering Flint River from Montezuma up the river to Everett Station are Pleistocene terrace deposits.

LAFAYETTE AND COLUMBIA MANTELS IN THE CHATTAHOOCHEE VALLEY
"In the vicinity of Columbus, both the Lafayette and Columbia formations are best shown in the railway cut, and in the ravines upon the Alabama side of the river. The upper of these consists of about ten feet of red loam underlaid by from one to four feet of coarse gravel. This formation rests

PLIOCENE

387

upon the eroded surface o-f the Tuscaloosa series. The C<>lumbia series

rests unconformably upon the older and constitutes the plains at Columbus,

which rise about one hundred feet above the river and 260 feet above the

sea. This later formation is made up of bluish sand and alluvial clay.

kbout five miles south of Columbus, just beyond Upatoi Creek, on the road to

Cusseta, there are other fine exposures of the older deposits.

Feet

"1. Orange loam . . . . . . . . . . . . . . . . . . . . . . 10

2. Laminated, colored sands with a streak of whitish clay;

this bed is completely cut through by the valley of an

ancient branch about twenty feet wide, which is now

filled with the over-lying red or orange loam .

6

3. White and stained clayey coarse sand

8

4. Gray sandy clay . . . . . . . . . . . . . . .

6

"On neighboring hills, the gravels are found at an elevation of about

350 feet above the river, which is two or three miles distant.

"At many points along the Chattahoochee River, this orange loam cap-

ping is characterized by drift logs at its base; these probably belong to the

younger system of deposits, altl;wugh sometimes of a different color trom

those at Columbus.

"Steward's Hill, six miles north of Georgetown, displays the finest ex

posures of the Lafayette series seen anywhere in Georgia. This hill rises

265 feet above the river; the lower 145 feet belong to Cretaceous beds; the

overlying 120 feet constitute the Lafayette sand or loam.

Feet

1. "First bench of loamy sand, drab or reddish; the lower

three inch'es ,cemented with iron

30

2. Second bench, like tqe first, with sandstone cemented

at base

10

3. Ditto of a redder color, but at base there are three feet

of sandy clay

20

4. Variegated colored laminated clayey sands

40

5. Ditto partially concealed

20

6. Cretaceous deposits

. 145

"The lamination is not always well marked. The sands vary from white to red. Through one of the beds there is a layer of coarse pellets, producing a fine conglomerate. In this region, the gravels occur along the sides of valleys tributary to the Chattahoochee, but are not found at Steward's Hill. The gravels appear to be characteristic of the plateau to which Columbus belongs. This condition is shown in the high terrace of Eufaula ( 125 feet above the river), where there is a thick gravel floor. That terrace is bounded on the west by hills covered with Lafayette loam. At Fort Gaines, a similar condition is found. The surface of the same terrace is covered with twenty feet of red clayey sand or loam, the lower part of which is composed of quartz gravel.
"The railway cuts east of Georgetown expose excellent sections. "Along the river, about four miles above Columbia, Alabama, a fine exposure of orange loam was seen rising twenty or thirty feet above the river. In this loamy deposit, a piece of gneiss was found, in, size 8 to 6 by 4 inches, and some smaller pieces of mica schist. These transported stones could not have been brought from a point nearer than Columbus, seventyfive miles distant in a straight line. They could not have been transported by waves, but were probably carried southward entangled in the roots of driftwood. "The terrace in the extreme southwest corner of the State, near Chattahoochee village, has approximately the same altitude as at Columbus and Fort Gaines. Its surface and sides are covered, throughout a vertical range, of one hundred feet, with the same orange-colored sandy clay or loam.

388

GEOLOGY OF THE COASTAL PLAIN

"From these descriptions, it will be seen that orange-colored or red
sandy loam extends througnout the whole length ot the river from the highest altitudes of the country to the pre~:~ent flood plains."

The Q.eposits on the plains bordering Chattahoochee River at Columbus, Eufaula, Georgetown, and Fort Gaines are Pleistocene terrace sediments which rest directly upon Cretaceous, Eocene, and Olig_ocene strata. There is question as to the age of some of the gravels on the upland east of Columbus, but since gravel beds are known in both the underlying Lower Oretact;ous beds and in the Eutaw formation of the Upper Cretaceous, it is considered probable that they are all of Cretaceous age. The section at Stewards Hill is referable in its entiretY: to the Ripley formation of the Cretaceous.

"LAFAYETTE AND COLUMBIA MANTELS IN THE INTERIOR OF SOUTHWEST GEORGIA

"Thrcughout the highlands of Decatur and Thomas counties conditions

similar to those along the great rivers prevail. Thus, near Whigham

station we see the following section:



Feet

"1. Orange or red loam passing beneath into a lighter and

more clayey layer . . . . . . . . . . . . . . . . . . 4- 8

2. Redish and light colored mottled clayey sand with light

patches of clay; only the upper portion is laminated; the

lower part is somewhat snarply defined, and in other

places apparently passes into . . . . . . . . . . . . . 8

3. Laminated white and purple clay with red micaceous and

sandy partings. This bed shows undulations . . . . 3

4. Laminated red sand with clayey partings . : . . . . . 6

"No. 1 belongs to the Columbia and possibly to the No. 2 and No. 3

Lafayette series. In the Attapulgus Creek district, the orange or red loam varies from two to eight feet, and often passes imperceptibly into bluer clay, which occasionally graduates into banded clay.

"On the Tnomasvilie road, nine miles east of Bainbridge, the orange loam

is conspicuous. There, a rolling hill-country, covered with this red deposit,

bounds the sand-covered plains of Bainbridge. In a washout, the lower

portion of the loam, which is 8 or 10 feet thi9k, contains irregular pockets

of cherty fragments derived from the adjacent rock. At one point, this

loam rests upon blue clay. In some localities, this subjacent clay is seen;

at others the underlying material is quicksand. The explanation of thrs

condition was not obtained until the observation was made in the railway

cut about a mile west of Climax, on the road to Bainbridge, showing the

following section:

Feet

"1. Orange or red loam passing below into a red and

white clayey material, with some ferruginous con-

cretions . . . . . . . . . . .. . . . . . . . . . . . 4-12

2. Laminated sands, in colors from white to black, with

clay film partings . . . . . . . . . . . . . . . . . 0-12

At the west end of this section the sand is traversed

by two seams of white clayey matter about 8 inches

thick. 'It rest upon the eroded surface of

3. Whitish sandy clay . . . . . . . . . . . . . . . . . . 4-8

4. A hand of sand from white to dark red in color with

some slightly clayey seams; exposed in places

8

5. Miocene, white sandy clay, exposed . . . . . . . . . tJ-16

PLIOCENE

389

"No. 2 is wanting at the eastern end of the cut, but No. 1 rests upon from 10 to 15 feet of a sandy clay (Miocene) No. 5 which is not exposed at the western end of the section. Two unconformable depostts succeed the Miocene; but the lower of the two is sometimes completely wanting. Thus is explained the occassional absence of the sand, which is so often seen beneath the loam; namely, on account of its entire removal by erosion, before the deposition of the superficial red loam.
"In many places, in these southern counties, the orange loam rests directly upon the deposits of apparently Miocene age. On the higher lands, the loam is not covered by any superficial material, but at elevations inferior to 200 feet above the sea, a superficial water washed sand (Columbia series) may be seen, at many places, resting upon the loam. This superficial sand, at the phosphate beds, west of Boston, has a depth of a foot and a half. Throughout the lower arid more level counties of MHchell, Miller, Baker, Dougherty and Calhoun, the loam is apt of itself to be sandy, and covered with a sandy soil, either directly derived from the loam, or perhaps indirectly by the waves acting temporarily in some lagoon, which may formerly have covered these counties. This last explanation appears to be sustained by the presence of duny sand ridges rising to a height of twenty feet, on the east side of the Flint River, opposite Newton.
"A further characteristic of this orange or red sandy clay or loam is that its lower portion consists of a bed of gravel, in the vicinity of the ancient valleys. Thus, on the hills, above the last bridge over the Upatoi Creek, the gravel occurs at an elevation of 350 feet above the Chattahoochee River, which is two or three miles distant. These pebbles diminish in importance on going southward, and were not seen near the Florida boundary. But, as if to take their place, fragments of limestone, or in phosphatic regions, pebbles of phosphate occur in portions of the beds. In this way the character of the subjacent rocks is detected by the hillocks being covered with such loose masses, secondarily derived from the drift.
"As was noted before, at one or two points along the Chatahoochee, drift boulders from the crystalline rocks far away were found. The same holds true along the Flint and in other regions. This evidence of partial transportation of the material of the loam is not needed to explain its source; for it is generally so charged with hydrated micaceous particles as to at once tell that a considerable portion of it has been derived from the decayed crystalline rocks of Middle Georgia; which had also contained the quartz veins, whence the quartz pebbles, in the gravelly portions of the formation, originated. However, their partial local origin is attested by the presence in many localities of fragments of the subjacent rocks."
The deposits in southwestern Georgia referred by Spencer to the
Lafayette formation are included in the present report in the Alta-
maha formation.
In 1898, in connection with his study of the clays of the Fall Line region, Dr. Geo. E. Ladd1 made some observations on supposed Lafay-
ette strata, occurring in the Fall Line region. Following the theories
advanced by McGee and Spencer, Ladd assumed that the Lafayette
formation was a surficial deposit which covered the entire Coastal
Plain.

"THE COLUMBIA AND LAFAYETTE FORMATIONS"
"The formations of the Cretaceous and Tertiary succeed each other, without any long continued land intervals, geologically speaking; and,
1Clays of Georgia : Geol. Survey of Georgia, Bull. No. 6-A, 1898.

390

GEOLOGY OF THE COASTAL PLAIN

in spite of the unconformities mentioned, they rest, one on another, in a gen-

erally conformable series. At the close of the Miocene Period, however,

South Georgia stood for a long time high above the sea, the great rivers

carved broad and deep valleys, cutting down, in places, to a depth of 350

feet below the general surface level, for a breadth of several miles, the

topogr::p1>1C features of the region becoming pronounced. (p. 88.)

"Following this land epoch, however, came a new subsidence, the shore-

line moving inland to the present Fall Line, and, in places, somewhat beyond

it. During this subsidence, when elevations, now 800 feet above the level

of the sea, were washed by its waves, deposits of sand, clay and gravel were

spread irregularly, sometimes to the depth of 150 feet like a huge mantle

over the hills and valleys, which had been carved out, during the land epoch.

The materials of this formation can be found all over southern Georgia.

They rest on the hill-tops, on their slopes, and on the floors of the valleys,

and greatly interfere with geological research. This formation is known as

the Lafayette. (pp. 88-&9.)

"After a comparatively brief subsidence, there was re-emergence, when

new valleys were cut, often through the Lafayette, and penetrating the

underlying strata. Then took place a final submergence and a deposition

of the superficial sands and gravels, which make up Columbia formati-on.

The Columbia and Lafayette formations are unconformable with reference

to each other; they also lie unconformably upon the Tertiary and Cretace-

ous strata; and along the margin of the Coastal Plain even upon the crys-

tallines of the Piedmont Plateau. *

* * (p. 89.)

"The Lafayette gravels are Ctlaracterized by cross bedding, rapid trans-

ition from coarse to fine material, and generally, by a deep-red color, result-

ing from the oxidation of iron-bearing material. It frequently has a mot-

tled appearance which is noticeable in the sides of gullies and cuts. The pre-

vailing red color is frequently broken by a net-work of gray and blue tints,

which mark the former position of the roots of trees and shrubs where the

iron oxide has been "reduced" by the organic compounds resulting from

their decay." (p. 90.)

Ladd states that Rich Hill, Crawford County, is capped with Lafayette strata (p. 91). As previously stated, the red materials on this hill are probably of Eocene age.

"Tne Fall Line crosses the Ocmulgee River beneath the Macon footbridge; and here are exposed boulders and outcropping ledges of the hard Piedmont crystallines. Overlying them are the Columbia terraces; and east and west mounting over, but capping, the Tertiary heights are the white, red and orange gravels and sands of the Lafayette. (p. 101.)

The thought expressed is that the terrace materials belong to the Columbia division of McGee, and that the Lafayette formation is confined to the heights and rests upon Tertiary strata. As previously stated, the gravels and red loams on the upland at Macon overlie Cretaceous strata and probably belong to the Claiborne group of the Eocene.
Gravel deposits occurring at Vineville and at Rutley [Rutland] are referred by Ladd to the Lafayette formation (pp. 102, 103). In the present report these are considered terrace deposits belonging to the Okefenokee formation (Pleistocene).
Ladd also described sands and gravels which he considered referable to the Lafayette formation, at Griswoldville, Jones Count;

PLIOCENE

391

(p. 106); at Gordon; at Mcintyre, Wilkinson County (pp. 120, 130) ; at Stevens Pottery, Baldwin County (pp. 138, 139) ; at Chalker, Washington County (p. 151); and near Belair, Richmond County (p. 161). These materials are said to form mantles over Cretaceous or Tertiary strata, or over both. After having studied many exposures in this region the present writers have reached the conclusion that Ladd has mistaken for the I~afayette formation both Eocene and Cretaceous. strata in place, and the residual creep materials derived from these strata. This opinion is based partly upon paleontologic evidence and partly upon the lithologic resemblances of the supposed Lafayette materials to the Eocene and Cretaceous strata of the region.
R. :M. Harper' has discussed the occurrence of supposed Lafayette deposits in Georgia as follows:
"When moroughly decomposed by atmospheric agencies the Grit can often hardly be distinguished from the Lafayette loam, and in railroad cuts and other artificial. excavations which exposes the indurated Grit it is sometimes impossible to say whether there is any Lafayette above it or not.
"The Lafayette probably covers more than 99 per cent. of the Altamaha Grit region, but its presence cannot easily be proved, for the reason just stated, and also because neither it nor the Grit is fossiliferous. Little if anything is known as to its maximum thickness in this region. In composition it is a loam, containing probably as much sand as clay. Farther inland it is often ,brick-red, but in the Altamaha Grit region, and in pinebarrens generally, its color is considerably lighter and might be described as terracotta."
Although assuming that the Lafayette formation is present as a surficial covering over practically all of the Altamaha reg~on, Harper admits that "its presence can not ellsily be proved." The present writers have not been able to differentiate any surficial formation .other than residual gray sands and the Pleistocene deposits which along the rivers and towards the coast rest upon the Altamaha beds as terrace accumulations. In their opinion the loams referred to the Lafayette formation by Harper are the weathered residual products of the Altamaha strata.
The following description of the Lafayette is given by Professor :McCallie:'
"Lafayette.-The Lafayette, whose exact position in the geologic time scale is still debated, like the Columbia formation, is a superficial deposit, covering most of the Coastal Plain. The formation consists of orange and vari-colored clays and sands, with local beds of gravel. The basal member of the formation along the Fall Line frequently becomes distinctly pebbly. These water-worn pebbles, which consist largely of quartz derived from the crystalline rocks to the north, occur irregularly distributed throughout the
'Annals New York Acad. Sci., Vol, 71. pt. 1, 1906. p. 23. 2Geol. Survey of Ga., Bull. 15. 1908, p. 30.

392

GEOLOGY OF THE OOASTAL PLAIN

Vll.ri-colored sandy clays, but more often they are found in layers or pockets.

They also occur in the basal member, at places, with fragments of white

clay forming more or less continuous layers. These phases of the lower di-

vision of the formation become less pronounced in the southern part of the

State, where sandy loam and vari-colored stratified clays predominate.

"The upper member of the formation differs from the lower in being

more uniform, both in physical structure and lithological character. Along

the Fall Line, at some points, it becomes quite pebbly; however, as a general

rule, it is made up almost entirely of massive reddish or motley sandy clays.

Frequently, the massive clays of the upper division are hardened into a com-

pact mass, having almost the consistency of sandstone. This indurated layer

resists the erosive action of surface water; and, by being undermined by

the washing away of the layers below, it often stands out in high, perpendic-

ular walls. Excellent illustrations of this mode of erosion are frequently

met with in the vicinity of streams, which have lowered their channels into

the underlying formations.

"The thickness of the Lafayette formation is quite variable. At some

places, near the northern margin, where it has been protected by the Colum-

bia sands, it attains a maximum thickness of more than 80 feet; at other

points, it has been entirely removed by erosion. These eroded areas are

quite irregular in outline, and may occur at any point throughout the

Coastal Plain. They are more frequently met with, however, in the vicinity

of the larger streams; yet, they are not entirely absent from the level piney

woods."



Following McGee. and others, McCallie has referred to the Lafayette formation deposits both older and younger than Pliocene.
In the opinion of the writers the existence of the so-called Lafayette formation in Georgia has not been proven. Assuming the terrane to be of Pliocene age, it is probable that at least a part of the lbeds referred in this report to the Altamaha formation are synchronous with it. Other than these the formation probably has no representatives in Georgia.

CHARLTON FORMATION

The name Charlton is derived from Charlton County Ga., and is applied to an argillaceou5 limestone and clay formation exposed in the banks and bluffs of St. Marys River, from Stokes Ferry, 11 miles ~:>outh of St. George, Charlton County, Ga., to Orange Bluff, near Kings Ferry, Fla. This formation, however, may also occur on the Satilla River' and the probability of limestone beds at Burnt Fort, 12 miles northeast of Folkston being equivalent, has been mentioned on a preceding page. From a study of the fossil collections from St. Marys localities, Dr. Vaughan has classified the formation as
probably of Pliocene age. In previous publications there are a few scattered references to
the formations exposed along St. Marys River, but the authors have

w. lNOTEI.-A fossiliferous
l!md of M.. Thrift, six of the marl on St. Marys

marl has recently been found near the Satilla River, on

miles east of Winokur, River and is of probable

Charlton Pliocene

Coul).ty. It or Mwcene

argesee.m-0bl.esv.s

the ome

GEOLOGY OF 7'BE OOA T A L PL.H 1\" OF GFJO IWf.!

PLA7'B XXV II.

C HARLTO~ FORllA'.fJON. . T. :\IAH Y!': RIYER. AT A. C. L . R. R. BRIDGE , THREE MILE 0 THEA '1' OF FOLK TON. CHARLTON COUNTY, GA.

PLIOOENE

393

made little or no attempt at correlation. The relations of the Charlton formation to other formations on St. Marys River are graphically shown in the profile, fig. 4, page 47.
The relations of the Charlton formation to the Miocene are not definitely known. At Stokes Ferry, the top of the formation is perhaps 30 or 35 feet above sea level, and it descends gradually do\\n stream, reaching tide level. According to the geological m2p of Florida by Matson and Clapp' the Jacksonville formation (Mioc{lne) outcrops at elevations of 50 to 100 feet above sea level, n short distance south and east of St. Marys River. Beds, from which Dr. Vaughan has identified Miocene fossils, are exposed at low tide at Owens Ferry, Satilla River, Camden County, Ga. In view of these vccurrences of Miocene the Pliocene beds on St. Marys River, if correctly correlated, may occupy an erosion basin in Miocene strata, or, if the latter are absent beneath them, th~y may rest in a similar basin in pre-Miocene strata probably referable to the Alum Bluff formation (Oligocene). The great thickness' attributed to the Miocene at Jacksonville, 460 :eet, and the fact that the Miocene there is supposed to lie unconformably upon the Vicksburg, makes the former alternative seem the more probable one. There are no data for estimating the thickness of the formation; only 12 or 15 feet have been observed in natural exposures.
The strata are poorly fossiliferous, and it is difficult to correlate the beds on the basis of their fos'Sil contents. The formation is characterized at two or three localities by an abundance of ostracods. All of the fossils which have been identified from the formation are given on succeeding pages.
Regarding the age of the formation, Dr. Vaughan, in unpublished notes, says:
"None of the material [fossils] between Hicks Bluff and Orange Bluff can be older than Pliocene, and although not a single extinct species was collected, it may be Pliocene. The two species of ostracods listed by Doctor Bassler from Rand Landing and Clay Landing appear to be recent. As the material from Stokes Ferry seems to be the same as that from Rand and Clay landing it is probably of the same age. [Pliocene.]"

LOCAL DE!T:AILS
ST. MARYS RIVER.
Stokes Ferry.-The point farthest up St. Marys River at which hard rock of the Charlton formation appears is at Stokes Ferry, 11 miles south of St. George, Ga. The exposure is in a low bluff on the F~orida side, about 100 yards below the ferry. Orange-colored loam
'Second Ann. Rept., Geol. Survey of Florida, 1909. 2Idem.

394

GEOLOGY OF THE COASTAL PLAIN

overlain by gray sand appears in an escarpment a short distance back from the river at a higher level than the strata described in the following section:

Section at Stokes Ferry

Pleistocene

Feet

Satilla formation.

4. Dark colored sand; contains vegetr ble matter; thickness

variable . . . . . . . . . . . . . . . . . . . . . . . 4

3. Coarse, greenish, argillaceous sand, Line of rounded, flat,

or discoidal quartz pevoles, some as much as two

inches in diameter, along base . . . . . . . . . . . . 2

(Uncrmformity)

Pliocene ?

Charlton formation.

2. Greenish or urab, stiff, tenacious clay containing calcar-

eous concretions; ostracods and some phosphatic parti-

cles, maximum . . . . . . . . . . . . . . . . . . . 4 to 5

1. Limestone containing ostracods, small gastropods,

and casts of small bivalves . . . . . . . . . . . . . 1

The limestone at the base is a hard, spongy, or cellular, siliceous rock; about one foot is exposed at low stages of the river. Beds Nos. 1 and 2 appear for about 150 or 200 feet along the river bank

beyond which they are replaced by the more recent Pleistocene.

Loose fragments of bones and mammal teeth were found here, and from their position on the slopes of the bluff it is inferred that they

came either from bed No. 2 or bed No. 3.

Hicks Bluff.-Except at one point only late Pleistocene sands and clays are exposed at this locality; however, the orange-colored, argillaceous sands, which in this region overlie the Charlton formation, appear in an escarpment leading to the higher land about 300 yards back from the river.

Section a.t Hicks Bluff.

Pleistocene. Satilla formation. 3. Dark-colored, thin line of quartz p,eobles at base .
(Unconformity) Pliocene ?
Charlton formation. 2. Greenish, sticky, sandy clay, maximum . . . . . . 1. Soft, argillaceous, fossiliferous limestone; contains Pecten gibbus, Phacoides multilineatus and Laevicardium, maximum thickness . . . . . . . . .

Feet. 3 to 10
4 4

The limestone and clay appear as a small erosion dome covered by late Pleistocene sand. The limestone is richer in fossils than at any other locality on the nver. A few fragments of bones and mammal teeth were found.

PLIOCENE

395

No exposures of hard rock are known between Hicks Bluff and Red Bluff.

Red Bluff.-The section at Red Bluff on the Florida side of the river, two miles east of St. George, Ga;, is described as follows:

Section at Red Bluff.

Pleistocene? 4. Partly concealed, and in part gray sand .
3. Vari-colored sand Pliocene ?
Charlton formation. 2. Drab, sandy clay . . . . . . . 1. Sandy, fossiliferous limestone

Feet 10 26
7 1.5

From the limestone bed Dr. Vaughan has identified the following fossils :

Fossils from limestone bed at Red Bluff.

Leda acuta Conrad. Barbatia marylandica Conrad. Area umbonata Lamarck.

Pecten sp. Lithophaga sp. Phacoides or Diplodonta.

Schoolhouse Blnff.-A section similar to the preceding is exposed' at Schoolhouse Bluff, about four miles below the Georgia Southern and Florida Railroad bridge, and one mile below old Drewry Ferry.

Sect1:on at Schoolhouse Bluff.

Pleistocene.

Feet. In.

7. Gray or white sand at top of blufl' . .

4 to 5

6. Orange-colored, argillaceous sand with clay at

the base, and beneath the clay a thin line of

small quartz pebbles . . . . . . . . . . . 12 " 1o

Pliocene ?

Charlton formation.

5. Greenish, fine-gra:ined, sticky clay . . . . . . 3

4. Soft limestone, and siliceous, fossiliferous ma-

terial with ostracods and Rangia cuneata . 1

3. White, calcareous clay . . . . . . . . . . . 3

2. Hard, earthy, argillaceous limestone . . . . v

4

1. Chalky, argillaceous limestone with small gas-

tropods . . . . . . . . . . . . . . . . . 2

6

Ramd Landing.-This bluff is located about two miles below the old Drewry Ferry, and about five miles, by land, below the Georgia Southern and Florida Railroad bridge.

Section at Rand Landing.

Pleistocene?

Feet ln.

12. Poorly exposed orange-coloreu argillaceous

sand; line of small quartz pebbles along

base . . . . . . . . . . . . . . . . . . 20

396

GEOLOGY OF THE OOASTAL PLAIN

Pliocene ?

Charlton formation.

Feet. In.

11. Clay ( ?) . . . . . . . . . . . . . . . . . }

10. Thin, nodular, limestone layer . . . .

4 to 5

9. Greenish clay . . . . . . . . . . . . . .

8. White and greenish laminated clay with poor-

ly preserved prints of fossils . . . . . . . 0

4

7. Greenish, laminated clay . . . . . . . . . 1

6

6. Cream-colored, argillaceous limestone . . . 0

6

5. White, calcareous clay . . . . . . . .

2

4. Soft calcareous material containing ostra-

cods, Bythocypris, Oytherella . . .

1

3. Limestone, non-fossiliferous . . . . .

0

10

2. White, calcareous clay . . . . . . . .

2

1. Rather hard, argillaceous limestone .

2

10

Stratum No. 1 is apparently arched into a small anticline. It appears at the water's edge at two points about 100 yards apart, and halfway between these two points it rises about three feet above the water.

Clay Landing.-This bluff is on the Florida side of the river and about one and one-half miles northeast of Toledo, Ga.

Section at Clay Landing.

Pleistocene ( ?) . 5. Slope covered by gray sand; underlying strata probably orange-colored, argillaceous sand . . . . .
Pliocene ? Charlton formation. 4. Contact with the above not exposed. Greenish, f.negrained, sticky or plastic clay containing small, calcareous nodules,-exposed . . . . . . . . . 3. White clay . . . . . . . . . . . . . . . . . . . 2. Soft, friable, calcareous, sandy clay or marl; contains ostracods, poor casts and prints of mollusks, fish teeth and fish vertebrae . . . . . . . 1. White, hard, argillaceous limestone, no fossils . .

Feet 15 to 20
5 2
3 1

Two ostracods, Bythocypris sp. and Cytherella sp. have been identified from bed No. 2. According to Dr. R. S. Bassler these species are either Recent or close to Recent species.

Nettles Landing.-There is a high bluff at an old log slide one and one-half miles by land above Cow Ford. The strata are not very well exposed.

Section at Nettles Landing.

Pleistocene? 11. White, surficial, quartz sand at top of bluff 10. Not well exposed, slope covered with white sand; probably an orange-colored, argillaceous sand underlies the surface, line of small, well-rounded

Feet 3 or 4

PLIOCENE

397

quartz pebbles at base from which springs emerge ........... Pliocene ? Charlton formation? 9. Poorly exposed, plastic, greenish, fine-grained clay
8. Concealed . . . . . . . . . . . . . . . . . . . .
Charlton formation.
7. Thin layer of hard, argillaceous limestone, probably but a few inches thick . . . . . . . . . . . .
6. Clay . . . . . . . . . . . . . . . . . . . . . . .
5. Thi~s~~:es~o~e .l~y~r. ":it~ .a .few p.o~r .p~i~ts. ~ }
4. Drab, laminated clay . . . . . . . . . . . . . } 3. Soft, sandy, argillaceous limestone, Modiolus, Oy
therea?, Rangia . . . . . . . . . . . . . . . 2. White, hard limestone-no fossils . . . . . . . 1. Earthy, compact limestone . . . . . . . . . . .

Feet 15 to 20
3 5
? 4 2
5

Stratum No. 11 is a part of the gray or white surficial sand covering the upland plain. The river at this point impinges against the scarp of the Okefenokee plain or plateau, and the late Pleistocene or Satilla terrace deposits do not appear, which accounts for the difference in the height of this bluff as compared with the bluffs at Sawpit Landing and Cow Ford.
Stratum No. 10 is probably the equivalent of the upper parts of the bluffs at Calico Hill and near Folkston.

Cow Ford.-The next exposure of the argillaceous marl or limestone of the Charlton formation appears in the right bank of the river about one-half mile below Cow Ford and nine miles south of Folkston.

Section at Cow Ford.

Pleistocene or Recent.

4. Dark or chocolate-colored sand, white at the sur-

face

. . . . . . . . . . . . . . . . . . .

Pliocene?

Charlton formation.

3. Plastic, sandy clay . . . . . . . . . . . . . . } 2. Soft, yellow, argillaceous limestone; contains
poorly preserved fossils-Modiolus, Pnacoiaes Oaraitamera sp. . . . . . . . . . . . . . . . 1. White, laminated, fine-grained clay . . . . . .

Feet 5
4

The lowest Pleistocene terrace, which at this point IS a palmetto "flatwoods," is about three-fourths of a mile wide. It lies 10 to 15 feet above low water; at its inner margin there is an abrupt rise of about 30 or 40 feet from this lower plain to the upland plain.

398

GEOLOGY OF THE COASTAL PLAIN

Sawpit Landing.-Calcareous clay and chalky limestone are exposed at this locality, two miles by the river above the ferry at ' Traders Hill.
Section at Sawpit Landing.

Feet In.

Pleistocene.

Satilla formation.

8. Stiff, greenish clay

3

(Unconformity)

Pliocene?

Charlton formation.

7. White, calcareous clay

1

6. Calcareous sand and sandy limestone

0

6

5. soft, white, calcareous clay, fossiliferous; con-

tains Leda, probably acuta, Pecten g2bbus,

Anomia simplex, Phacoides or Diplodonta, Tel-

lina sp.

1

4. White or yellow limestone

1

3. Greenish clay .

1

2. Drab, calcareous clay

2

1. Soft, gray or white, chalky limestone or marl at

low tide

2

Bed R o. 8 is considered Pleistocene in age; the clay forms a flat terrace about one mile wide bordering the river.

Folkston.-A good exposure occurs three miles southeast of Folkston on the Florida side of the river at the end of the new bridge of the Atlantic Coast Line Railroad. The section in detail is as follows:

Section of bluff on St. Marys River, at end of railroad bridge, three

miles southeast of Folkston.

Feet ln.

Pleistocene ?

24. At top-gray, fine, incoherent, quartz sand .

2

(Unconformity)

23. Mottled clay and sand 22. Stiff, plastic clay

4

6

3

6

21. Orange-yellow, clayey sand

5

6

20. Yellow sand

4

19. Drab, sandy clay

4

18. Yellow sand

2

6

17. Greenish, stiff, sandy clay with line of quartz peb

bles at base

(Unconformity)

4

6

Pliocene?

Charlton formation.

16. Greenish, laminated clay

1

15. White limestone layer 14. Drab, calcareous clay

0

4

0

8

13. Limestone

0

3

12. Drab clay

0

6

11. Greenish, laminated clay

1

6

10. Gray, fossiliferous, sandy clay or phosphatic marl;

Pecten gibbus

1

PLIOCENE

399

Feet. In.

9. Thin layer of compact, argillaceous limestone . . 1

8. Green or drab, highly fossiliferous clay, ostracods

and clay casts of fossils . . .

2

6

7. Limestone . . . . . . . . . . .

0

3

6. Green, fossiliferous clay, Pecten

1

5. Limestone . . . . . . . . . . .

0

6

4. Clay . . . . . . . . . . . . . .

0

4

3. White limestone . . . . . . .

0

6

2. Laminated, fossiliferous clay :

2

6

1. White, argillaceous limestone .

0

6

The beds from 17 to 23 inclusive lie horizontally, and are probably
of Pleistocene age; from 1 to 16 the strata belong to the Charlton formation. These beds have been disturbed from their original positions and dip northward 30 to 45 degrees. Bed No. 24, the surficial sand which covers the flat, upland plain reaches a thickness of eight feet or more, and is sharply defined from the underlying, red, argillaceous sand, being quite different in lithologic appearance; it is, therefore, considered a later deposition. About 50 yards east of the bridge there is a friable, coquina-like layer, possibly the equivalent of No. 10 of the aboYc section. Of the fossils collected from the Charlton formation at this locality Dr. Vaughan has identified the following :

Fossils from the Charlton formation three miles southeast of Folkston.

Pecten gibbus Linnaeus Anomia simplex d'Orbigny

Rangia cuneata (Gray)

. Limestone or marl is reported at the base of the bluff at Calicc, Hill, two miles below the bridge; when visited this was not exp0sed. The bluff or hill is about 40 feet high and the strata exposed are the equivalents of the upper 30 feet of the section at the railroad b"!"itlge, with the possible exception of the bluish, fine-grained, plastic clay seen near the base of the hill.
Bet\veen the preceding exposure and Chalk Bluff, a section of which is given below, only late Pleistocene sand and clay appea1 }n tl,c river banks.

Cha,lk Bluff.-This locality is about one-half mile above Orange Bluff, described below, and exhibits a similar succession of strata.

Section at Chalk Bluff.
Feet In Pleistocene.
Satilla formation. 5. Bluish or greenish, fine-grained, plastic, sandy clay 2

400

GEOLOGY OF THE COASTAL PLAIN

Pliocene?

Charlton formation.

Feet In.

4. Stiff, white, chalky or calcareous clay, thin layers

of limestone . . . . . . . . .

2 6

3. Greenish or drab, fullers earth-like clay . .

1

2. White, chalky clay . . . . . . . . . . .

2

1. Sticky, greenish, calcareous clay . . .

1

Stratum No. 5 underlies a flatwoods terrace, as at Orange Bluff. Poorly preserved fossils occur in the lower part of the bluff. A Pecten and probably a Modiolus were identified.

Orange Bluff.-This bluff is on the Florida side of St. Marys River, about two miles above Kings Ferry, Fla. It is a low blnff,about 10 feet high at low tide. The fossiliferous limestone of the Charlton formation is not exposed on the river below this point:

Section at Orange Bluff.
Feet In Pleistocene
Satilla formation. <l. Stiff, greenish, sandy clay, weathered brownish; contains Ostrea virginic.a; thin line of smooth, perfectly rounded quartz pebbles, reaching one inch in diameter, at base . . . . . . . . . . . 5 (Unconformity)
Pliocene ? Charlton formation. 1. Soft, white or drab, argillaceous limestone or marl, becoming more argillaceous at the top. The rock is variable in hardness and the river has washed out small holes at the base of the bluff. Fossils collected. Thickness at low tide . . . . . . . 4 6

Stratum No. 2 forms the clay flatwoods terrace which borders the river. The fossils in stratum No. 1 are poorly preserved, but are most abundant at the base of the bluff and can be collected best at low tide. From the collections made at this locality Dr. Vaughan has identified the following:

Fossils from Orange Bluff.

Leda acuta Conrad Pecten gibbus Linnaeus Fragum
Laevicardium

Phacoldes multilineatus (T. and H.) Chione cancellata (Linnaeus) Mulinla lateralis (Say)

ALTAMAHA (LAFAYETTE) FORMATION

NAME
The first description of beds which probably included parts of this formation was given by Dr. R. H. Loughridge' in 1884, in the Tenth Census, although the name "Altamaha" was not used, and the for-

'Tenth Census, vol. 2, 2, p. 15.

PLIOCENE

401

mation was described as "Miocene or Grand Gulf" sandstone. The name "Altamaha grit" was applied by Dr. W. H. Dall' in 1892, from typical exposures along Altamaha River. Using the name "Altamaha grit," Dr. R. M. Harper' studied the formation mainly from a phytogeographical standpoint and gave some details regarding its distribution, lithologic character, and age. He referred it to the Pliocene, and stated "there is every reason to believe that the 'Altamaha grit' is the equivalent of the Grand Gulf formation of the States farther west." Prof. S. W. McCallie' has also given a brief description of the deposits. In 1908 Veatch described the deposits, traced their boundaries, and applied to them the name "Altamaha" formation, employing the word formation rather than grit, since so many lithologic phases were discovered to which the term "grit" was not applicable.
As explained on later pages, there is some reason for believing that the deposits here included in the Altamaha formation constitute a complex embracing strata representing every period from the Oligocene to the Pleistocene.

DEFINITION
Stratigraphic Relations.-The Altamaha (Lafayette?) formation has been observed overlying Eocene, Oligocene, and Miocene(?) strata, and may be considered in a certain sense a surficial formation. In Burke and Washington counties in the northeastern part of the Coastal Plain the formation overlaps the Claiborne, some phases of which it resembles texturally; the Claiborne sands, however, bear fossils, upon the evidence of which they may be distinguished from the Altamaha bed~. The relations between the two formations may be observed at Waynesboro and Tennille in railroad and road cuts. It overlies the Vicksburg in the counties of Laurens, Pulaski, and Dooly, and is perhaps in contact with the Vicksburg and Chattahoochee in places along the west side of Flint River, as far south as' Decatur County. Near the base of the formation thme are, in places, mechanically included flint fragments derived from the underlying older formations. The formation probably directly overlies the Chattahoochee and Vicksburg formations in Screven and Burke counties, although actual contacts have not been discovered. Throughout the greater part of the area of its occurrence the formation overlies the Alum Bluff formation from which it can not in

'Bull. U. S. Geol. Survey No. 84, p. 84. 2Annals New York Acad. Sci., vol. 17, pt. 1, Sept., 1906. 3Bull. Geol. Survey of Georgia No. 15, 1908, p. 31. science, n. s., vol. 27, Jan., 1908, pp. 71-74.

402

GEOLOGY OF THE COASTAL PLAIN

all cases be easily discriminated. The two formations are similar lithologically near the contacts at many places, and the Alum Bluff formation does not always bear fossils; it is, therefore, not .improbable that beds properly belonging in the Alum Bluff formation have been included in the Altamaha division. Probably a large part of the Altamaha materials were derived from the Alum Bluff beds, rendering the former lithologically similar to the latter. Weathering of both formations has also made a sharp distinction difficult in many localities. Unconformities with the Alum Bluff formation were noted at Climax, Forest Falls, Cairo, and in some of the bluffs on Altamaha River above Doctortown. Thb relations of the formation to the Alum Bluff formation at particular localities will be discussed in subsequent pages. Beds tentatively regarded as referable to this formation overlie, unconformably, fossiliferous Miocene strata at Doctortown and at Bugs Bh1ff on Altamaha River and at Porters Landing and other localities on Savannah River.
The relation of the formation to the probable Pliocene bed exposed on the King plantation, six miles south of Atkinson on Satilla River, cannot be determined with certainty, but the latter is believed to be contemporaneous with at least a part of the beds here included in the Altamaha (Lafayette?) formation. In the dredgings at Brunswick, Miocene, Pliocene, and Recent shells were obtained, but there are no natural exposures of the beds and the relations of the Altamaha (Lafayette?) formation to possible Pliocene must remain in doubt.
It has not been possible in all cases satisfactorily to determine the relation of the terrane to deposits of Pleistocene age. In fact, there is some grounds for the belief that the strata here included in the Altamaha (Lafayette?) formation may be a complex, embracing on the one hand not only beds of Pliocene age but also beds of Miocene and Oligocene age, and on the other hand beds of Pleistocene age, the latter being reworked products of the Altamaha materials, and therefore resembling them. However, the evidence at present available is not sufficient to justify an attempt to subdivide the formation.
Overlying the Altamaha (Lafayette?) formation there is nearly everywhere a thin mantle of loose, gray, or brownish sand, mainly of residual origin, but probably in part of Pleistocene age. The sand rarely shows stratification lines, contains but very little clay, and can be easily differentiated from the Altamaha materials. These surficial sands in places reach a thickness of 20 or 30 feet, but the average is not more than two or three feet.

PLIOCENE

403

Lithologic Characters.-The Altamaha (Lafayette ?) formation is an extensive deposit of irregularly bedded sands, clays, and gravels, locally indurated. On the whole the deposits are homogeneous, but locally become a heterogeneous mixture of the above mentioned components. The indurated sands and the conglomerates comain a peculiar greenish or greenish-gray, disseminated clay, and are described as "gray or greenish aluminous grits;" the pebbles are predominantly subangular, often lath-shaped, and the sand is universally harsh or in sharp, angular grains; there is a great abundance of feldspar, both in pebbles and semi-decomposed, disseminated grains, and phases of the formation may be appropriately described as "feldspathic grit"; a negative peculiarity is the total absence of calcareous phases. The weathered surface loams are mottled and splotched in red, yellow, purple, and gray tints, the surface aspects differing in this respect from those of any other Coastal Plain formation. These striking effects are probably due to unequal weathering, oxidation, and unequal distribution of iron materials. Thrse loams are not a 1\lter deposition but are dm to the weathering of the Altamaha materials, although in many places they appear to overlie unaltered beds unconformably. The formation is very coarse-grained, even at points 100 miles from its northern margin. It contains sands, gravels, conglomerates, and clays, all of \Yhich are locally indurated; the sandstones, conglomerates, and claystones do not differ essentially in composition from the non-indurated materials. These different phases do not constitute stratigraphic units but are local depositional
n phases produced by shifting currents. The grit and sandstone phases of the Altamaha (Lafayette formation, the peculiar nature of which attracted the special attention of those who first studied the terrane, are typically exposed along Altamaha River. They appear as gray or greenish, aluminous sandstones, more or less mottled and stained by iron oxide. At some localities pebbles are embedded in the sand and clay matrix, the
whole cemented into a conglomerate; but, except for the pebbles, these beds do not appear different from the typical sandstone of the Altahama formation. The percentage of clay in the indurated rock varies from five to ten per cent. to a percentage sufficiently high to render the rock an indurated clay rather than a sandstone. The sandstones are generally soft and friable, the cementing material being an opaline silica, but locally they become extremely hard. In places the sandstones are arkosic,-that is, composed of quartz, feldpar, mica, and other minerals of igneous rocks,-in which cases the interstices are filled with clay and the whole cemented with silica, producing rocks not un-

404

GEOLOGY OF THE OOASTAL PLAIN

like some of the indurated phases of the Lower Cretaceous strata near the Fall Line. These lithologic peculiarities have been observed at widely separated localities, the sandstones being in all cases easily identified, although entirely devoid of fossils. Except along Altamaha River, surface outcrops are not abundant. In the interstream areas there are occasional small tracts a few acres in extent, in which jutting beds of sandstone, 15 or 20 feet thick, form barren, rocky flats. Exposures of grit or hard rock are most common in the northern part of the Altamaha region but are not observed near the coast or near the Florida boundary line. It is believed that these isolated exposures are local indurations only and do not form continuous sandstone beds.
The clays of the Altamaha formation are fairly uniform in texture and composition throughout the area of their occurrence. They are greenish or drab, very fine-grained and plastic, and always more or less sandy. They have a low specific gravity absorb a high percentage of water, and occur in thick, irregular pockets or thin, lenticular layers, never persisting as individual beds over any large area. In places they grade into or are abruptly replaced by sands and sandstones. Greenish clay, full of coarse, angular, quartz particles and subangular, decomposed, feldspar pebbles, is of frequent occurrence in the ~ormation. The clays are locally indurated, the cementing material being opaline silica.
The sands of the formation consist chiefly of coarse, quartz sand and are red and yellow, or orange, in color, with an occasional brownish tint. They are more or less argillaceous and in places contain layers of quartz and feldspar pebbles. The feldspar pebbles constitute a large percentage of the gravel layers. A characteristic of the pebbles is their angularity, some being lath-shaped, showing scarcely any rounding of the angles. The pebbly feature is nowhere very prominent and is exceptional rather than general. In a few localities the pebbles are rather large, attaining a diameter of four or five inches. Near the Atlantic coast and in the southwestern part of the State the sands are, in places, fine-grained, rarely micaceous, crossbedded, and interstratified with thin layers and leaves of plastic clays. In places these clay layers do not exceed one inch in thickness. Such a structure is seen in the exposures of the formation near Jesup, at Waynesville in Wayne County, and near Whigham in Grady County.
In the northern part of the region the sands are always coarse. They are never pure and contain large amounts of disseminated clay. It is only near the Atlantic coast and near the Florida State line that

PLIOCENE

405

they are fine-grained, and even here there are some coarse-grained materials.
While in the foregoing the sands, clays, and sandstones are described separately they do not form stratigraphic units. Irregularly-bedded sands, clays, and sandstones may be seen in the same vertical section, the clays frequently being replaced by sands and vice versa. In places the sands and gritty clays may be seen to grade horizontally from non-indurated to indurated rocks, or from soft sands and clays into grits typical of the Altamaha formation.
Beds of gravel and conglomerate occur but form only a small pro, portion of the whole. They are interbedded with the clays, sands,
and sandstones, and grade into them. Throughout the sands there are pebbles scattered promiscuously, or they may be arranged in lines a few inches thick. The conglomerates differ from the sandstones or grits only in the size of the rock particles. The beds of gravel and conglomerate are not persistent over large ilreas and are rarely more than eight or ten feet thick.
The pebbles making up the conglomerate are mainly quartz, quartzite, and feldspar. The quartz pebbles may be as much as three inches in diameter, and fragments of feldspar one and one-half inches in diameter have been observed. A feature of most of the gravels is the angularity or subangualrity of the pebbles.
The cementing materials of the conglomerates are clay and iron oxide. The material cementing the clays is probably opaline silica.
Brown iron oxide "pebbles" or nodules are in many places so abundant as to warrant special mention. Throughout the "wiregrass" region they occur in such quantity that the lands are termed "pebble" or "pimple" land in contrast to the lands covered by gray sand, and the "pebble" or "pimple" land is generally recognized as being superior in fertility. These nodules are a surface phenomenon produced by weathering; the iron oxide of the argillaceous sands is segregated into irregular, small bodies which are subsequently worn
smooth. The "pebbles" vary in size from buckshot to eight or ten
inches in diameter, but the buckshot size is most common. The
mineral composing them is limonite or some closely allied iron min-
eral with clay and sand impurities. They are round or tubercular in
shape, and have a slick or water-worn appearance, yet there is not
much evidence of their having been transported by water and their
smoothness may be due to attrition by raindrops. These pebbles
were noted as being especially abundant at Stillmore, Fitzgerald,
Douglas, Glenville, Pelham and Doerun.

406

GEOLOGY OF THE OOASTAL PLAIN

Thickness.-The formation is variable in thickness; it is spread over an immense area and is, in a certain sense, a surficial deposit, being attenuated both to the northward and to the southward, and probably presenting the greatest thickness near the middle of the area in Georgia. The thickness, 350 feet or more, given by Veatch' in a previous paper is exaggerated for the recent investigations have demonstrated that underlying Oligocene clays, sands, and sandstones, penetrated in well borings to the depth indicated, were erroneously referred to the Altamaha (Lafayette?) formation. The maximum thickness can nowhere be observed in natural exposures and estimates must necessarily be made in part from well records. Observed and estimated thicknesses throughout the terrane are: Decatur County, not exceeding 50 to 75 feet; near Pelham, probably not greater than 100 feet; in southern parts of Grady, Thomas, Brooks, and Lowndes counties, absent, or not exceeding 40 or 50 feet; Waycross, 50 feet; Doctortown, 40 feet; Tilman Ferry Bluff, Altamaha River, 65 feet. Throughout the northern border, in Dooly, Pulaski, Dodge, Laurens, Johnson, Washington, Emanuel, Jenkins, and Burke counties, the thickness varies from six to eight feet to a thickness of probably 50 or 75 feet.
The maximum thickness certainly will not exceed 150 feet and the greatest thickness will be found in Laurens, Montgomery, Toombs, Coffee, Irwin, and Tift counties. It should be borne in mind that we are not always able to differentiate definitely the Alum Bluff and Altamaha formations and the figures given above are likely to be too great rather than too small, on acount of possible inclusion of Alum Bluff beds.

Paleontology and age.-Except for a few pieces of wood and fragments of oyster shells, the latter found in a gravel bed at Collins, and probably a mechanical mixture in the gravel, the typical Altamaha (Lafayette?) formation is devoid of fossils. There are, therefore, no paleontologic criteria for determining the age and stratigraphic position of the formation. Shells of probable Pliocene age occur in a deposit on Satilla River, six miles south of Atkinson, but the relation of the typical Altamaha formation to this deposit has not been conclusively determined. It is probable, however, that the Satilla River bed is contemporaneous with at least a part of the Altamaha (Lafayette ?) formation. Loughridge2 described the Altamaha beds in part and referred them to the Miocene; Dall' in 1892 also referred the formation to the Miocene, but after the recogni-

'Science. n. s., vol. 27, January, 1908, pp. 71-74. 2Tenth Census, vol. 6, pt. 2, p. 16. 'Bull. U. S. Geol. Survey, No. 84, p. 81.

PLIOCENE

407

tion of the Oligocene in the Coastal Plain, referred it to the uppor Oligocene.1 A part of the b~ds described by Dall are undoubtedly
of upper Oligocene age.

The formation is younger than the Alum Bluff formation (Oligocene) which it overlies in bluffs of Altamaha, Oconee, Ocmulgee, and other rivers. In places on Altamaha and Savannah rivers deposits here provisionally referred to the Altamaha (Lafayette~) formation overlie unconformably beds correlated with the Duplin :Miocene of North Carolina; of course, such beds are younger than Miocene strata upon which they rest. The formation is overlain in part by surficial gray sands of Pleistocene age. There seems, therefore, to be more grounds for referring it to the Pliocene or early Pleistocene than to any other series. The possibility of some of the beds here included in the Altamaha (Lafayette '~) formation being older, and some younger, has been discussed on a preceding page. It is probable that at least a part of the beds are the time: equivalent of the so-called Lafayette formation.

Areal distribution.-The Altamaha (Lafayette ?) formation is the most widespread terrane in the Coastal Plain, covering in part an area of approximately 21,000 square miles, or three-fifths of the Coastal Plain area of the State. Its northern boundary is approximately marked by Waynesboro, Midville, Tennille, Dublin, Cochran, and Unadilla, and its western boundary is Flint River; thence a large part of the entire area south and east to Florida and the Atlantic Ocean is underlain by this formation. The most typical beds occur along Altamaha River and the formation underlies practically all the area known as the "wire-grass region." In the southern parts of Brooks, Thomas, and Grady counties, it is thin and partly removed by erosion. Near the coast deposits which may be remnants of the formation appear on the first marine terrace, (Satilla Plain), near Kingsland, Woodbine, and Pearl in Camden County and at a number of places near Savannah, Chatham County.

Physiographic expression.-The formation where it forms the surface produces a peculiar topography and a part of the area of its occurrence constitutes one of the major topographic divisions of the Georgia Coastal Plain, described in the first page of this report as the "Altamaha upland." This area is one of low hills with gentle slopes and softened outlines; of shallow, saucer-shaped valleys, often not more than 40 or 50 feet deep; of sluggish, clear-water streams,
1Eighteenth Ann. Pept., U. S. Geol. Survey, pt. 2, p. 340.

408

GEOLOGY OF THE COASTAL PLAIN

bordered by swamps and sand hammocks ; of "bays" and cypress ponds.
Altamaha and Oconee rivers have cut deep valleys into the formation and precipitous bluffs are found along their courses and form an exception to the general type. The topography is in contrast to the broken, hilly areas of the ,Cretaceous and Eocene near the Fall Line; to the limesink topography to the west and southwest; and to the flat, sand-coated plains to the southeast.
Structure.-Inasmuch as the formation is not regularly bedded and there are no persistent layers, folding, faulting, etc., could hardly be detected even if they existed. Some inclination of beds from the horizontal was noted near Minter, Laurens County, but this was probably due to irregular deposition. A pecularity of the formation is the numerous local unconformities and abrupt horizontal changes in the character of the materials. The highest ele vations are about 470 feet near Tennille and 450 feet at Ashburn, thence there is a gradual slope to the Atlantic coast, where the formation appears only a few feet above sea level.
Conditions of deposition.-The character of the deposits indicates a shallow water deposition, and affords evidences of conditions which find no parallel in the earlier Tertiary systems. The heterogeneous character of the deposits, the angularity and arkosic nature of much of the gravel, the rapidly shifting conditions of deposition, the numerous local unconformities and abrupt changes in the lithology, the absence of marine fossils and of any calcareous and glauconitic deposits, and other chemical and lithologic characteristics of marine sediments, precludes the classificatiop. of the Altamaha as a true marine deposit. The deposits are of terrestrial origin, produced as flood-plain and delta accumulations which, probably merged into littoral deposits.
At the beginning of the Pliocene there was an uplift of the Piedmont Plateau, a southward tilting, and consequent rejuvenation of the drainage. 8-reat accumulations of detritus were dumped on a plain facing the sea, and coalescing deltas of coarse sediments rapidly accumulated and encroached upon the sea. The arkosic character of the sediments and general angularity of the pebbles indicate that this was a period of either great aridity or of extreme cold, in which disintegration predominated over decomposition. Much of the Altamaha has a true fluviatile or flood-plain aspect, while in some localities the presence of interstratified, fine-grained clay and sand suggests the presence of fresh-water lakes within the deltas. It is probable that the coarse delta deposits first laid down

PLIOCENE

409

were reworked and carried farther south>vard by streams. The source of the material was probably mainly from the Piedmont region, but there is evidence that the older Coastal Plain formations furnished a share of the detritus.

LOCAL DETAILS
The details concerning lithologic character, stratigraphic relations, etc., from which the general conclusions preceding were drawn, are given in the following sections and descriptions:

ALTAMAHA RIYER

The characteristic, lithologic features of the formation, its relation to the underlying Alum Bluff formation, and questionably, its relation to the Miocene, are exhibited in the bluff exposures on Altamaha River.
The sections exposed at Grays Landing, 11 miles below the Fo1ks are:

Section at Upper Bluff, Grays Landing.
Pleistocene ? 7. At top, thin veneer of gray sand and gravel . .
Pliocene ? Altamaha (Lafayette?) formation. 6. Characteristically mottled, argillaceous sand . 5. Massive bed of gray, feldspathic sandstone or grit
Oligocene. Alum Bluff formation. 4. Gray argillaceous sand . . . . . . . . . . . . . 3. Interstratified sand and clay; clay layers a few inches thick; the sand has the appearance of the Alum Bluff sand in the southwestern part of the
State . . . . . . . . . . . . . . . . . . . . . 2. White, minutely jointly, fullers earth, contains
round, siliceous concretions . . . . . . . . . . 1. Semi-indurated, greenish argillaceous sand . . . .

Feet
8 to 15 15
6
10 2 to 12
2

Section at Lower Bluff, Grays Landing.

Pleistocene ?

9. Gray sand and gravel at the top, forms a , thin

veneer over the surface .

Pliocene?

Altamaha (Lafayette ?) formation.

8. Mottled, argillaceous sand .

8

7. Sandstone and gray sand .

20

(Unconformity)

Oligocene.

Alum Bluff formation.

6. Fullers earth-like clay and sand . ,

6

5. Greenish argillaceous sand . . . .

5

4. Greenish day . . . . . . . . . . .

2

3. Massive sand, containing thin clay layers

6

2. White fullers earth . . . . . .

6

1. Greenish, rather comnact sand . .

1

410

GEOLOGY OF THE COASTAL PLAIN

The massive Altamaha sandstone or grit also appears at Fail-inRock, 18-mile post, and at Piney Bluff, at the 20-mile post.

Section at Fall-in-Rock Bluff.

3. At top, reddisa sand . . . . . . . . . . . . 2. Massive bed of gray or greenish sandstone, forms
a projecting ledge and a precipitous bluff . . . 1. Greenish and gray clay and sand, softer than the
above rock . . . . . . . . . . . . . . . . . .

Feet
25 10

It is probable that layer No. 2 belongs to the Altamaha formation; however, no unconformity appears between 1 and 2 and there are no fossils or other conclusive evidence of the age of the strata.

Section at Lower End of Piney Bluff.

Pliocene?

Altamaha (Lafayette?) formation

3. Abrupt bluff of greenish or gray, massive sandstone

or grit . .

. ............. .

Oligocene.

Alum Bluff formation.

2. Compact, gray sand . . . . . . . . . . . . . . .

1. Sandy, fullers earth-like clay; no fossils, but ap-

pears similar to the Alum Bluff deposits of

soutnwestern Georgia . . . . . . . . . . . .

Feet
25 3 ( ?) 6

At Tillmans Ferry, 36 miles below the Forks, the entire bluff is made up of the Altamaha formation. The bluff is 65 feet high; the lower 35 feet is more or less indurated, and is a coarse feldspathic grit; the rock above is not well exposed and the upper slope is covered with sand and gravel and a few sandstone projections appear. The sandstone is conglomeratic in places and pebbles threefourths of an inch in diameter were noted. Nothing resembling typical Alum Bluff materials appear.
Lower Sister Bluff, at the 49th mile-post, presents fine exposures. The lower, softer strata are carv:ed into .a "bad-lands" type of erosion and the bluff is the most picturesque on the river.

Section at Lower Sister Bluff
Pliocene ? Altamaha (Lafayette?) formation 7. Beginning at the top, mottled grit . . . . . . . 6. Drab and greenish, friable aluminous sandstone . 5. Coarse grained, pebbly grit . . . . . . . . . . . (Unconformity.)
Oligocene. Alum Bluff formation. 4. Greenish, argillaceous sand, finer in texture than the above ....... .

Feet. 10
8 22
8

PLIOCENE

411

3. Drab, sandy clay . . . . . . . . . . . . . . . . 2. White sand, thin clay 1ayers . . . . . . . . . . 1. G;reenish and drab, compact, aluminous sand, finer
in texture than No. 2. Laminated clay at the base . . . . . . . . . . . . . . . . . . . . .

Feet. 10 3
25

Proof that the strata in the upper and lower parts of the bluff are of different ages is not as patent as is desirable, for the beds exhibit no striking lithologic differences, and no fossilE> were found. However, at the upper bluffs, one mile above, there is better evidence of an unconformity.
The upper portions of the sections at Fort James (58th milepost), have the characteristic appearance of the Altamaha formation but here again there is some uncertainty about the age of the beds.

Section at Upper Fort James Bluff
Pliocene? Altamaha (Lafayette ?) formation 6. At top, pebbly mottled, argillaceous sand 5. Coarse, mottled grit . . . . . . 4. Greenish sandy clay . . . . . . . . . 3. Sandstone . . . . . . . . . . . . . 2. Semi-indurated aluminous grit . . . (Unconformity)
Oligocene. Alum Bluff formation. 1. Greenish compact clay and sand mixture, perhaps finer in texture than the beds above . . . . .

Feet 30 12
2%
6 4
25

Section of Lower Fort James Bluff.
Pliocene ? Altamaha (Lafayette ?) formation 5. Beginning at the top, mottled sand not well exposed . . . . . . . . . . . . . . . . . . . . . 4. Coarse, gray grit . . . . . .. . . . . . . . . . . 3. Greenish or gray fine argillaceous sand, compact, massive .... 2. Sandstone or grit . . . . . . . . . . . . . . . .
Oligocene Alum Bluff formation ? 1. Fine-grained, greenish, argillaceous sand . . . . .

Feet
30 12
7
2%
20

At Oglethorpe Bluff (69th mile-post), the indurated phase of the Altamaha does not appear, and the formation is represented by varicolored sand and by thin lenses of clay.

Section at Oglethorpe Bluff.
Pliocene ? Altamaha (Lafayette?) formation. 6. Beginning at the top, red and yellow sand; contains some clay and is mottled in the upper part 5. Clay layer . . . . . . . . . . . . 4. Yellow and white crossbedded sand . . . . . . .

Feet
18 2 25

412

GEOLOGY OF THE COASTAL PLAIN

3. Purplish clay lens . . . . . . . . . . . . . . . . 2. Coarse-grained, crossbedded, arkosic sand, feldspar
and angular quartz gravel . . . . . . . . . .

Oligocene

(Unconformity)

Alum Bluff formation ?

1. Greenish, compact argillaceous sand, no fossils .

Feet. 5
20
15 (max.)

Section at Linden Blufr 73 Mile-post.
Pliocene ? Altamaha (Lafayette?) formation 6. Mottled argillaceous sand (top of section) 5. vVhite, coarse, to very coarse sand with some gravel at the base . . . . .
(Unconformity J Miocene?
4. White and yellow sandy clay . . 3. Black silty clay . 2. Quartz pebbles in a matrix of bluish sandy clay
(Unconformity.) Oligocene?
Alum Bluff formation ? 1. Greenish compact argillaceous sana

Feet. 12 25
2 5 5
18

The beds which are marked questionably Miocf!ne, occupy the same position in the section as the fossiliferous Miocene bed at the next bluff below,-Bugs Bluff. The lowest bed is referred to the Alum Bluff formation on the basis of the unconformity. Bugs Bluff is nearly a mile in length; the section given is at the lower end of the bluff, and is one mile by land from Doctortown.

Section at lower end of Bugs Bluff.
Pleistocene 7. Gray sand, capping bluff . . . . . . . . . . . .
Pliocene? Altamaha (Lafayette?) formation? 6. Mottled, argillaceous sand . . . . . . . . 5. Coarse, white crossbedded sand, becomes coarser and p~bbly at the base . . . . .
Miocene Duplin marl 4. Faintly laminated, yellow and white sandy clay 3. Bluish mud . . . . . . . . . . . . . . . . . . 2. Shell and pebble conglomerate, contains Pecten eboreus, Mytilus conradinus . . . . . . . . . (Unconformity)
Oligocene? Alum Bluff formation ? 1. Greenish, compact, argillaceous sand . . . . . .

Feet 2
10 28
5.! 6.! 1.!
10

PLIOCENE

413

Section at Doctortown

Pliocene ?
Altamaha formation ? 6. Yellow and mottled argillaceous sand, has the typical surface aspect of the Altamaha . . . . o. White and yelow crossbedded sand containing thin layers of small quartz pebbles . . . . . . 4. Red and yellow sand containing thin clay laminae
Miocene. Duplin marl
3. Calcareous fossiliferous sand or sandy friable
marl . . . . . . . . . . . . . . . . . . . . . 2. Bluish sand containing the Miocene fossils, Pecten
eboreus, Mactra congesta . . . . . . . . . . . (Unconformity)
Oligocene? Alum Bluff formation ? 1. Coarse, bluish or greenish compact clayey sand to water's edge

Feet. 10 10 10
1 4
7

The Sansavilla bluffs, 27 and 28Yz mil,es, respectively, below Doc-
tortown, are the last high bluffs on the river. Paleontologic evidence of the age of the beds is lacking ; the succession of beds is similar to that at Doctortown and Bugs Bluff.

Section at Upper Sansavilla Bluff
Pleistocene Okefenokee formation 3. Fine, brown and white quartz sand, covering a terrace plain
Pliocene ? Altamaha formation ? 2. Bluish-gray sand, interstatlfied with white, thinly laminated clay; the clay layers contain small bits of plant remains . . 0 0
Miocene or Oligocene ? 1. Bluish, compact, argillaceous sand . . . .

Feet.
30 5( ?)

Section at Lower Sansavilla Bluff.

Pleistocene.

Okefenokee formation.

8. Fine brown and white, incoherent quartz sand .

10

Pliocene ?

Altamaha formation ?

7o 6.

W W~h\~iteey ccll~ayy.eyl~ys~ar:nd~n..e-.~r.~i.~e.~.ot.~i.~l~0 l0oa ~i ~~ te : ~

5. Sand

0

0

0

0

0

0



0



0



18

4.

Thin clay layer

. 0



o. . . . . . . oo. . .

a. Argillaceous sand

. . . . o . 0







0





0

2. Clay, fullers earth-like . . o . . . 0 o o o . .

Miocene or Oligocene ?

1. Coarse, crossbedded compact, argillaceous sand .

8

414

GEOLOGY OF THE COASTAL PLAIN

EAST AND NORTH OF ALTAMAHA RIVER

On the Macon, Dublin, and Savannah Railroad, between Vidalia and Dublin, various lithologic phases appear in the cuts. The formation near the surface is an orange yellow loam, beneath which is a mottled, argillaceous sand splotched with red, yellow, white, and purple. Crossbedded sands and local beds of gravel appear, and at anumber of places are drab claystones and gray, aluminous sandstones. The formation is uniformly overlain by a gray, incoherent sand, from two to six feet thick.
A bed of coarse gravel consisting of pebbles and cobbles was noted in a railroad cut on the east side of Ohoopee River, two miles east of Adrian.

Section in railroad cut two miles east of Adrian.

Altamaha formation 4. Gray, incoherent sand . . . . . . . . . . . . . 3. Yellow, argillaceous sand . . . . . . . . . . . 2. Gravel bed, maximum thickness . . . . . . . . 1. Coarse, gritty clay and argillaceous sandstone, typical Altamaha . . . . . . . . . . . . . .

Feet
b 3 2.5
12

The gravel bed is not a persistent layer and soon thins out, proving that it is merely a lens in the Altamaha (Lafayette ?) formation. The pebbles are mostly quartz, but a few pebbles of decomposed feldspar and vitreous flint, which has the appearnce of Vicksburg flint, occur; unlike most of the Altamaha gravel the pebbles are smooth, well rounded, and of large size, some three or four inches in their longest diameter. The lower bed contains coarse fragments of crystalline quartz in which flakes of mica occasionally occur. This is evidence that the detritus was derived directly from the Piedmont Plain.
Characteristic phases of the Altamaha formation occur at Stillmore, Emanuel County. The surface is covered with small, brown, iron oxide concretions about the size of buckshot, and the weathered part of the formation presents a mottled or "calico" appearance. The best exposure appears in the deep cut of the Central of Georgia Railway within the town limits.

Section at Stillmore.

Altamaha formation?
7. Gray sand residual . . . . . . . . . . . . . . . 6. Yellow loam, presenting a mottled or "calico" ap-
pearance . . . . . . . . . . . . . . . . . . . 5. Yellow and drab clay layer . . . . . . . . . . 4. Mottled purplish and gray argillaceous sand . . 3. Greenish sand, containing a small amount of clay 2. Drab, "stickey", sandy clay . . . . . . . . . . 1. Aluminous grit or sandstone . . . . . . . . . .

Feet 2%
6 2 3
3% 3% 2

PLIOOENE

415

At Ohoopee station, Toombs County, there is a cut about 25 feet deep in which the sands and clay beds exhibit local unconformities.
On the south side of Pendleton's Creek, two miles south of Ohoopee, there is a rough, craggy bluff of Altamaha sandstone, 15 feet high. The rock is made up principally of sharp quartz sand and a small amount of disseminated clay, and is similar to the sandstone at other localities. No fossils occur.
At the Jack Williams cut, four miles west of Collins, typical clay and aluminous grit are exposed.

In a cut of the Seaboard Air L.ine Railway three-quarters of a mile west of the station at Collins, Tattnall County, purplish sand and gravel layers are overlain by orange-colored, sandy loam. The locality is of interest since fragments of oyster shells, which could not be specifically identified, were found in a gravel layer 10 feet from the top of the cut. These shells may have been transported with the gravel. This is the only locality in this formation where fossil animal remains have been found. The pebbles are small, not exceeding an inch in length or diameter, angular or E>Ubangnlar, and consist principally of quartz with a small percentage of decomposed feld.spar.

Grits and claystones, similar to those described above, outcrop on

the farm of Dr. Donaldson, on Lott Creek, one mile northeast of

Register. There is a rugged bluff 10 feet high; the rock is fine-

grained, and the cementing substance is opaline silica; parts of the

sandE>tone are quartzitic, as at some other localties, although this is

n not a charactertistic phase. It can not always be certainly deter-
mined whether such materials belong to the Altamaha (Lafayette

formation or to the Alum Bluff formation.

At Ludowici, Liberty County, coarse, mottled sands with thin lay-

.ers of clay appear in a cut at the factory of the Ludowici Roofing

Tile Company. These sands and clays resemble the materials of the

Altamaha (Lafayette ?) formation.



Red sands resembling Altamaha materials were noted beneath the

Pleistocene gray sands between Darien Junction and Ludowici, and also beneath the gray sands between Darien Junction and Darien.

At Waynesboro and Greens Cut, Burke County, the formation appears in railroad cuts. It consists of mottled, argillaceous sands and

loams, easily distinguishable from the red sands of the Claiborne group which it overlies.

A good exposure appears in a railroad cut three miles north of

Munnerlyn, Burke County.

416

GEOLOGY OF THE OOA"STAL PLAIN

Section in railroad cut, three miles north of Munnerlyn.

Altamaha formation 3. Mottled sand, and drab, massive clay, oxidized red 2. Coarse-grained sandstone or grit . . . . . . . . 1. Bluish-gray clay containing coarse grains of quartz and feldspar . . . . . . . . . . . . . . . . .

Feet. 10
5
10

The clay is slick and unctuous, has a high air shrinkage, and when dry crumbles into very hard lumps. Similar clay occurs near Screven approximately 100 miles to the southward.
On the L. L. Brasselle place, six miles south of Midville, bluish or drab claystone, and sandstones or grits, appear in a rather pictureque bluff about 12 feet high. At a lower level a white quartzitic sand bears poorly preserved fossils, and oyster shells embedded in a white, calcareous sand have been thrown from a nearby well. The fossil-bearing beds undoubtedly belong to the Alum Bluff formation. The claystones or grits observed at this locality probably belongs to the Altamaha formation. They contain no fossils. There are no exposures showing the two phases in contact.
Sandstones and gritty claystones appear at Parramore Hill.

. Section in railroad cut north of Parramore Hill Station

Altamaha formation 4. Weathered red and yellow, sandy clay . . . . 3. Gray, coarse-grained sandstone . . . . . . . 2. Drab or chocolate-colored, semi-indurated clay 1. Very hard, massive, drab clay . . . . . . .

Feet. 4
2 3 7

The sandstone is a local induration and not a persistent layer. Coarse, quartz grains are embeddt:d in the fine-grained ground-mass of the clay. There is no evidence of any overlying formation except a thin veneer of sand.
Mottled, argillaceous sands, tentatively referred to the Altamaha (Lafayette ?) formation, overlie Miocene strata at Porters Landing, Trowel Landing, and at Sisters Ferry on Savannah River, and similar materials appear in cuts of the Seaboard Air Line Railway three miles north of Clyo in Effingham County. At Ebenezer Church, 30 miles above Savannah in Effingham County, a small thickness of red sand with thin, laminated clay layers overlie Miocene beds at an elevation of about 40 feet above the river; these are probably of the same age as the other Savannah River occurrences jw;t noted. These deposits may all prove to be Pleistocene terrace deposits. .
North of Savannah, along the Seaboard Air Line Railway, red sands appear at a few places beneath the gray surface sand, and are similar in lithololgic appearance to the red, argillaceous sands of Effingham County.

GEOI, OGl' OF THti OAS7'. 1f, l'L.II X 01-' GEORG I A

PL.l7' B XXl'TJT.

B. IL\RA C" I' F:RT!:iTIC' )lO'I'TLl:-\G lX WEATriER ED PHA."E J1' 'L'ITE ALTA)! .\ II.\ FOR:\IATION, UT OF .\ TLi\:-\ '1'1 COAST L l:-<F: HATLROAD. WE _r OF ~A IHO. GRADY COUNTY.

PLIOGEJVE

417

In the vicinity of Savannah red sands containing thin clay laminae and sandy beds appear at a number of localities and may represent the Altamaha formation. The difficulty of correlating these deposits with the Altamaha, however, is at once ""parent, since they are unfossiliferous and only widely separated exposures occur. They are older than the gray sands which veneer the first marine terrace, and older than the Pleistocene muds which also occur in basins on this terrace. The red sands ,themselves, however, may be of Pleistocene age. Exposures of these materials v. ere noted in cuts of the Montgomery branch of the Seaboard Air Line Railway, three, four, and nine miles west of Savannah, and in cuts of the Jacksonville branch of the same system one-third of a mile south of Florida J unction, all in Chatham County.
Along the Seaboard Air Line Railway, between Savannah and Altamaha River, red sands and mottled, sandy clays, probably corresponding to the deposits noted in the Yicinity of Savannah, occur at Burroughs, Limerick, and Arcadia.
WEST OF ALTAMAHA A::"\"D OCO::"\"EE RIVER
At Kramer, five miles west of Abbeville, Wilcox County, the formation has an arkosic character. Feldspar pebbles an inch in length were noted in a conglomerate which appears in the railroad cut, onehalf mile west of the station. The rock is composed of quartz, feldspar, mica in minute flakes, and small grains of a black mineral, probably ilmenite; these minerals are in a matrix of white clay, and silica is the cementing agent. The quartz varies from small grains to angular pebbles an inch in length. Some of the feldspar is but little decomposed. Such large fragments of feldspar this distance from the Fall Line are of unusual interest and are not found in any of the older Coastal Plain formations.
At Fitzgerald, Ben Hill County, the Altamaha (Lafayette?) formation appears at the surface as an argillaceous, massive sand, mottled red and white, covered by gray, incoherent sand. Brown, iron oxide "pebbles" are abundant and vary from the size of buckshot to three or four inches in diameter. They are evidently derived from the Altamaha formation by weathering but have subsequently been worked into the gray surface sands which overlies the Altamaha. Loose beds of these pebbles were noted in the gray sands along the Atlanta, Birmingham, and Atlantic Railroad track west of Fitzgerad, near the railroad shops.
Outcrops of indurated Altamaha sandstone and claystone occur a short distance north of Fitzgerald on the Bowens Mill road.
In a cut of the Southern Railway, one mile north of Helena, Tel-

418

GEOLOGY OF THE COASTAL PLAIN

fair County, the lens structure of the clay beds and the characteristic, coarse, gritty texture of the formation are exhibited.
Large, brown, iron oxide accretions, 8 or 10 inches in diameter, irregularly rounded, occur at the surface in the Yicinity of Broxton and Douglas, Coffee County.
At "the Rocks" nine miles northeast of Broxton, there is 20 feet of fine-grained, aluminous sandstone and claystone exposed in a narrow, rugged ravine. The rock bears no fossils, and its stratigraphic position is determined entirely by its lithologic resemblance to indurated phases of the A-ltamaha at other localitiet:~.
An excellent exposure of feldspathic grit or sandstone occurs at the 33Dth milepost on the Southern Railway, two miles northeast of Hazelhurst, Jeff Davis County. There is 10 feet of rock exposed; a short distance south of the rock exposure, the rock retains its texture and composition, but is not indurated, suggesting that the sandstones of the Altamaha are local indurations only and not continuous beds.
The Altamaha (Lafayette ?) formation appears in the railroad cuts at Jesup, \\"ayne County, hut is largely obscured in this part of the State by a thin coYering of gra.v sand. In a cut of the Southern Railway, throe miles southeast of J osnp, the exposure has the lithologic appearance of the Altamaha, but may be an Okefenokee Pleistocene deposit. The formation here contains' coarse gravel and large chunks of silicified wood. ln the clay pits of the brick-yard at Odessa the formation consists of alternating layers of fine-grained, plastic clay and ferruginous quartz sand. Neither the clay nor sand layers are persistent, and the two intergrade and replace each other. Some of the sand is very coarse, being made up of angular quartz fragments as large as peas.
Characteristic, lithologic features and structure again appear in the cuts two to two and one-half miles south of Screven, wayne County. Coarse, gritty clay similar in appearance to that at Munnerlyn, Stillmore, Helena, and other localities north and west is exposed. No exposures of the underlying older Tertiary formations appear.
Characteristic Altamaha clays and sands appear in a cut one mile northeast of Blackshear, Pierce County, the weathered surface phase of which is a mottled, argillaceous loam; there are local unconformities between sand and clay beds, and the sand is coarse in texture and angular. The sands and clays are similar in composition to the sandstones and claystones of the formation to the north and west, d~ffer ing only in being unconsolidated.
Characteristic Altamaha materials appear in the numerous railroad :md roacl cuts in the vicinity of \Va.'>'cross, Ware County. The

PLIOCENE

419

most instructive exposure is in a cut of the Atlantic Coast Line Railroad, two miles north of \Vaycross. Here are revealed pecularities of deposition, local unconformities, and the relation of the mottled, argillaceous sands to the less altered parts of the formation, and to the gray sands which cover the plain.
Somewhat similar sands and clays appear in Red Bluff on the right bank of Satilla River, four miles east of Raybon, Wayne County, and about eight miles above the King Plantation bluff. No fossils were found.

Section at Red Bluff
4. At top, light yellow, incoherent sand (Pleistocene) Altamaha (Lafayette ?)
3. Mottled sand containing a small amount of disseminated clay . . . . . . . . . . . . .
2. White, red, and yellow, fine sand , . . . . . . 1. Gray, very sandy clay . . . . . . . . . . .

Feet 3
10 15
4

The only means of establishing the correspondence in age of these beds with the typical Altamaha farther west, is by tracing the beds; this is hindered by the gray sand covering and the lack of continuous exposures.
Sands and clays similar to those exposed in a cut three miles southeast of Jesup occur at the brickyard at Waynesville, Wayne County.
A locality of much interest in connection with the discussion of the Altamaha formation is the bluff on Satilla River at the King plantation, six miles south of Atkinson, for fossiis occur in the basal bed of the section and there is some probability that the beds are contemporaneous with the Altamaha beds exposed at Waycross and Blackshear, about 25 miles to the westward.

Section at King Plantation
9. Gray sand (Pleistocene) Pliocene
8. Bluish, sandy clay, laminated; red splotches due to weathering . . . . . . . . . . . . . .
7. Gray, sharp sand; a small amount of disseminanated clay, some small quartz pebbles . . . .
6. Drab clay layer . . . . . . . . . . . . . . . . 5. Gray sand, containing clay laminae an inch or
two thick . . . . . . . . . . . . . . . . . . 4. Gray, fine-grained, very sandy clay . . . . . . . 3. Gray sand . . . . . . . . . . . . . . . . . . . 2. Yellow sand, fragile molds of shells . . . . . . . 1. Bluish, laminated argillaceous sand, containing
fragile shells and a few smap bone fragments

Feet 1
4
8 2
8 3 2 2
2

From the shell bed No. 1 Mr. T. H. Aldrich identified several species and regards the horizon as probably Pliocene.

----

420

GEOLOGY OF THE COASTAL PLAIN

Fossils from bluff of Satilla River, King Plantation, six miles south

of Atkinson) identified by T. H. Aldrich.1

Rangia cuneata (Gray) M:ulinia lateralis (Say) Mulinia congesta (Conrad) Dosinia sp?

Modiolaria sp? Gemma purpurea, H. C. Lea Neretina sp?
Neverita sp?

New Species

Potamides saltillensis Potamides cancelloides Paludestrina u.lana Amnicola saltillensis

Amnicola georgiensis Amnicola expansilabris Planorbis antiquatus

There is no good evidence of an unconformity between the fossiliferous bed and the upper part of the bluff. Although no definite, structural break was detected in the section there is some ground for believing that a part of the section above the fossiliferous layer, in addition to the surface gray sand, should be referred to the Pleistocene and not to the Pliocene.
On the Jacksonville branch of the Seaboard Air Line Railway at Waverly, Woodbine, Colesburg, and Kingsland, in Camden County, red sands, which are probably of the same age as the red sands in the vicinity of Savannah are exposed in the shallow cuts. Although resembling the Altamaha materials, and here tentatively referred to that formation, they may eventually prove to be Pleistocene terrace deposits. These red sands are covered with a thin mantle of surficial, gray sands.

WESTERN AND SOUTHERN LOCALITIES

Drab claystones and gray sandstones appear near the Georgia Southern and Florida Railroad, one-half mile north of worth, Turner County.

Section one-half mile north of Worth.

Altamaha (Lafayette ?) formation. 6. Upper part of hill partly concealed, projecting beds of sandstone and conglomerate . . . 5. Drab, sandy claystone, massive . . . . . . . . . 4. Mottled clay layer . . . . . . . . . . . . . . . 3. Gray sandstone or grit in places very hard . . . 2. Mottled clay . . . . . . . . . . . . . . . . . . 1. Indurated gray or drab, fine textured clay; breaks with an angular, conchoidal fracture . . . . .

Feet.
20 20 1.5 5 5
8

At this locality indurated sands and clays may be seen grading into non-indurated materials which have the mottled aspect so characteristic' near the surface throughout the Altamaha terrane.

1 Nautilus, vol. 24, No. 11, March, 1911, p. 131.

PLIOCENE

421

In a_ cut of the Atlantic Coast Line Railroad near the bridge, one-
half m1le east of Sylvester, Worth County, the following section was observed:

Sedion in railroad cut one-half mile east of Sylvester.

Feet. In.

Altamaha (Lafayette?) formation

7. At the top of the cut, orange-colored loam con-

taining small, iron oxide "pebbles'' . . . . . 3

6. Yellow, crossbedded sand containing small angular

quartz pebbles; thin layers of clay in the sand 6

5. Purple sand

0 3

4. Yellow sand . . . . . .. . . .

7

3. Purple sand . . . . . . . . .

0 4

2. Yellow sand . . . . . . . . .

0 6

(Unconformity.)

1. Purplish, sandy, massive bed of clay

2 6

The. characteristics displayed here are angular, lath-shaped, quartz }lebbles and unconsolidated sands.
In the vicinity of Ticknor and Doerun, Colquitt County, there are areas of typical "pimple" or "pebble" land, or land strewn with small, brown, iron oxide concretions resutling from the weathering of Altainaha materials.
Pelham, Mitchell County, is located on the top of the Altamaha escarpment which parallels Flint River. Near the surface there is a red or mottled, argillaceous loam overlain l,y a carpet of gray sand. Drab and purplish, very sandy clays occur ben8ath the surface formation. "Pimple" land occurs in this neighborhood also.
At Forest Falls, or Limesink, eight miles north of Whigham, Grady County, the Altamaha (Lafayette ?) formation varies in thickness from 8 to 20 feet. It overlies the Alum Bluff formation unconformably. At the base are gray and yellow sands and greenish, "gummy" clays, and at the surface red, case-hardened sands.
In southern Georgia and near the Florida line the formation has a lesser thickness, and over parts of Grady, Thomas, and Brooks counties is entirely absent. The topography of this part of the State has been influenced more by the Alum Bluff formation than by the Altamaha (Lafayette ?) formation. Sandstones and conglomerates which farther to the northward characterize the Altamaha terrane, are here absent.
In the railroad cuts and in an adjaoo.nt gully three-quarters of a mile west of Climax, Decatur County, the Altamaha formation overlies gray, or greenish and drab, interstratified clays and sands which probably belong to the Alum Bluff formation. Neither the upper nor lower exposures bear fossils, and there are differences

--

422

GEOLOGY OF THE OOASTAL PLAIN

of opinion as to a division of the strata. A detailed section at this

locality, made by Dr. Vaughan, has been quoted on page 348. All

th~ beds expo~ed from the level of the track up, except the gray, sur-

fiCial sands, m the second cut \vest of Climax have the lithologic

characters of the Altamaha formation at other localities.

The section in the second cut, not including the gully exposures

is as follows:

'

Section in railroad cut three-quaders of a mile west of Climax.

Altamaha (Lafayette ?) formation.
6. Beginning at the top,-gray incoherent sand
reaching a maximum of . . . . . . . . . . . 5. White and orange-colored, argillaceous sand, mot-
tled and massive, due to weathering . . . . . 4. Thin, siliceous crusts of limonite, apparently
marking an unconformity . . . . . . . . . . 3. Purplish, white and yellow, crossbedded sand . . . 2. Gray or drab clay layer with purplish splotches;
appears to be a lens in the sand; varies from 6 to 12 feet above the level of the track . . . 1. White, purplish, and yellow, crossbedded, coarse sand; very small percentage of disseminated clay; sand mainly angular, quartz grains;
maximum thickness . . . . . . . . . . . . .

Feet.
3 7 1 15
2.5 to 4
12

The beds between the level of the branch and the track level,

about 40 feet, probably belong to the Alum Bluff formation.

Characteristic, mottled, argillaceous sands of the Altamaha forma-

tion appear in the Atlantic Coast Line Railroad cuts near Fowltown

and Recovery in Decatur County. In a cut one and one-half miles

west of Recovery the contact wit_h Alum Bluff is exposed. Six.feet

of mottled, argillaceous sand rest unconformably upon two to four feet

of fine, gray sand containing a small amount of disseminated clay.

About 10 feet below the level of the track a sandy limestone referable.

to the Chattahoochee formation is exposed.

In the first cut east of the station at Whigham, Grady County, the

Altamaha formation appears as thin layers of red and purple sand,

alternating with laminated clay. Some of the clay laminae are not

more than a fraction of an inch in thickness, and the clay layers

have sand partings. In a cut one mile east, light, green clays of

the Alum Bluff formation appear overlain by orange-colored sand of

the Altamaha formation.

Fine exposures appear in the railroad cuts at Cairo, Grady

County. The formation here consists of mottled, sandy clays and

crossbedded, ydlow and red sands, with dull yellow loam at the sur-

face. The peculiar mottling or calico effect, due to weathering, is

shown in a photograph made in a cut west of Cairo. Plate

XXVIII-B.

PLIOCENE

423

The Alum Bluff formation is exposed in the terrace escarpments of Ocklockonee River at the 204th and 205th mileposts on the Savannahl\Iontgomery division of the Atlantic Coast Line Railroad. The overlying Altamaha (Lafayette ?) formation appears in a cut which extends from milepost 203 eastward for one-half mile; the formation here is a massive, argillaceous sand, mottled with yellow and gray. At Thomasville, Thomas County, the Altamaha is represented by a small thickness of red sand.
South of Cairo, Thomasville, Boston, and Quitman, the formation appears only on the higher hills as a capping. It consists mainly of red loam and may be easily confused with the red, argillaceous sand, residual from the Alum Bluff. North of these points the formation presents topographic and lithologic characters similar to those which prevail in the northern part of the Altamaha area.
One of the few exposures south of Thomasville which are considered referable to the Altamaha, occurs on the Tallahassee road, 12 miles south of Thomasville.

Section twelve miles south of Thomasville.

Feet.

5. At top of hill-gray, surficial sand . . . . . . .

2

Altamaha (Lafayette ?) formation.

4. Stratified sand and clay, mottled red and white,

coarser in texture than the underlying materials

20

Alum Bluff formation (contact obscured by weathering and creep.)

3. Residual, red, sandy clay

30

2. Greenish, fossiliferous clay

10

Chattahoochee formation.

1. Limestone . . . . . . . .

15

The materials capping the hill on the Mallet plantation on the Boston-Monticello road, four and one-half miles southwest of Boston, Thomas County, have much the appearance of the Altamaha formation, but their relation to the underlying residual sand of the Alum Bluff formation is obscure.
The A1tamaha formation appears in railroad cuts near Quitman, Brooks County, and near Kinderlou and Valdosta, Lowndes CountJ, It attains only a small thickness and is underlain by sandy clays of the Alum Bluff formation.
East and southeast of Valdosta the country is a flat, sand-covered plain in which there are few natural exposures. Yellowish, mottled .sands occur beneath the gray surface sands. It is probable that there is a small thickness of the Altamaha formation underlying this region. The mottled sand in the cut one mile west of Stockton has the appearance of this formation.

424

GEOLOGY OF THE COASTAL PLAIN

PLEISTOCENE

The Pleistocene deposits consist of thin, fluviatile and marme terrace accumulations of sand, clay, and gravel. The only systematic description of the Pleistocene of the Georgia Coastal Plain previously given is that of W J McGee.' :lVIcGee first studied the Pleistocene in the District of Columbia, gave it the name "Columbia formation" and differentiated it into three phases, the fluvial, inter-fluvial, and low-level phases. The formation was traced southward to the Mississippi and to ~Iexico. He recognized the three phases in Georgia and gave brief, general descriptions of them. Previous to McGee's studies, Lyell had already observed successive terraces on the coast Qf Georgia, and other observers have also mentioned them, but their geological significance seems not to have been fully presented.

In the present report the differentiation is based largely upon physiography, and the formations are described in greater detail than in McGee's report. The name Columbia as a group name is retained. The divisions are given in the following table:

Pleistocene

C 0

I bl um

a

{

S

a

t

i

lla

formation

{ group Okefenokee formation

Marine terrace deposits { Fluviatile deposits
Coastal terrace sand { Fluviatile deposits

The solution of the Pleistocene problem of Georgia, and in fact of the Atlantic Coast region in general, is conditioned largely upon a knowledge of topographic details. This knowledge can not be acquired until detailed topographic maps have been made available.
In Georgia the Pleistocene formations do not lie superimposed one upon the other, but occupy terrace benches at different topographic positions with respect to each other.
During the Okefenokee period gray sands and other sediments were laid down on a terrace plain of probable marine origin, now 60 to 125 feet above sea-level, and contemporaneous fluviatile terrace deposits consisting of gravels, sands, and loams, were laid down .on the "second" terrace skirting the larger rivers.
During the Satilla period gray sands and muds were laid down On a marine terrace, a flat plain 20 to 40 miles broad, bordering the coast at elevations of 15 to 40 feet above sea level, and corresponding terrace alluvium was deposited along the rivers.
Although the available data are at present too incomplete to admit .of a positive statement it is not improbable that an older Pleistocene

'The Lafayette formation; Twelfth Ann. Rept. U. S. Geol. Survey, pt. 1, 1S90-1891, lPP 353-521.

PLEISTOCENE

425

terrace plain exists to the westward of, and at a higher elevation than the Okefenokee terrace. Evidence of such a plain is to be seen in the topographic aspect of the country lying along the Atlantic Coast Line Railroad between Valdosta, Lowndes County, and Waycross, Ware County; along the Atlantic Coast Line Railroad between Pearson, Coffee County, and Waycross; and along the Southern Railway between Baxley in Appling County, to near Jesup, Wayne County. The general surface of the belt of country crossed by these railroads is a nearly level plain which gradually descends towards the coast. Along the first mentioned railroad there is a descent from an elevation of 215 feet at Valdosta to 140 feet at Waycross; along the second there is a descent from 205 feet at Pearson to 140 feet at Waycross; and along the third, a descent from 206 feet at Baxley to 155 feet at Odum.
The northern part of Effingham and the southern parts of Screven and Bulloch counties, also present the aspect of a plain similar to the Okefenokee Plain.

COLUMBIA GROUP
OKEFENOKEE FORMATION
The name Okefenokee is derived from Okefenokee Swamp, a great, swampy tract in southern Georgia covering parts of Charlton, Ware and Clinch counties. The swamp occupies a portion of the plain on which were laid down the deposits under consideration. The Okefenokee formation consists in part of coastal terrace deposits and in part of river terrace or fluviatile deposits. During this period there was probably a depression of the land, the coast line perhaps being 40 to 75 miles west of its present position. Coastal sands and probably other sediments were laid down forming a terrace, and contemporaneous fluviatile deposits were formed on terraces skirting the larger rivers as far as the Fall Line. The coastal terrace formed during this period is a flat plain 20 to 40 miles wide, which varies in elevation from 60 to about 125 feet above sea-level. It is covered with gray and white quartz sand. The river tffi'races lie 50 to 100 feet above zero water level, and form prominent topographic features along Savannah, Ocmulgee, and Chattahoochee rivers. The terrace deposits -consist of sands and gravels of fluviatile or fluvioestuarine origin. The two types of deposits will be described separately.

COASTAL TERRACE DEPOSITS
The coastal terrace phase of the formation is represented principally by a thin deposit of gray sand which covers the Okefenokee Plain, a topographic division which has been described in t]1e chapter

426

GEOLOGY OF THE COASTAL PLAIN

on physiography. The age of the formation is determined by the physiographic position and not by the evidence of fossils since fossils. are entirely absent. The western boundary of this plain is marked approximately by a line extnding from near Sisters Ferry on Savannah River, or Clyo, southeastward through the northern part of Bryan County, to about 10 miles north of Ludowici, Liberty County; thence to Jesup, and along the Atlantic Coast Line Railroad to near \Vaycross, Ware County; and thence to the western boundary of the Okefenokee Swamp. It includes the Okefenokee Swamp, and the towns of Folkston, Jesup, Ludowici, and Hinesville are situated upon it. Its eastern boundary is marked by an escarpment 20 to 40 miles from the coast, which separates it from the first or Satilla terrace. (The approximate area of this plain is shown on the sketch map, Fig. 1, p. 28).
The most conspicuous deposit on the plain referable to this period is a gray sand. Red and yellow sands ~ontaining thin clay layers and pebble beds underlie the surface sand and are doubtless in part Pleistocene, although in this report such materials are in most cases tentatively referred to the Altamaha formation. The Okefenokee formation is not in contact with any formation older than Pliocene and Miocene. On the west the sand of the Okefenokee Plain merges into the surficial sand of a higher plain and it is not always possible to draw a sharp line of demarkation between them. Swampy flats traversed by small creeks occur in the plain and probably the muds underlying these flatS' belong to this period of the Pleistocene.
The gray surface sand is composed almost entirely of subangular quartz particles, probably derived from the older Coastal Plain formations. On the whole, it is, perhaps, finer in texture and lighter in color than the upland .sands to the west. At the surface the sand is loose, incoherent, and structureless, but shows faint lines of stratification and current bedding at depths. At a few localities it is white at the surface and darker-colored beneath, the white phase having been formed by leaching and not as a separate deposit. A notable occurrence of white sand lies along the railroad between Ludowici and Darien Junction.
In the Okefenokee Swamp the only deposits known, aside from the recent peaty accumulations, are white, yellow, brown, and black sands,-the dark colors being due to large amounts of organic matter. The sand is in places indurated, due probably to a cement of iron oxide. This is the so-called "hard pan" of this area.
The thickness of the sand is small, probably averaging less than 10 fet over the whole plain. Good exposures appear at Folkston, where the aver,age thickness is six or eight feet, with local accumula-

PLEISTOCENE

427

tions reaching 15 or 20 feet; the sand is gray, almost white at the surface, and light yellow beneath. At other places over the plain the thickness varies from two or three to 10 or 15 feet.
The plain which the Okefenokee sand covers is in general flat and almost featureless. Some of the larger streams vvhich traverse it have bluffs 30 or 40 feet high, but these are exceptional. The erosive power of rainwater is lessened by the porous sand, and ravines and gullies are rare. The main streams have few tributaries. The plain is dotted with cypress ponds and swamps due to original inequalities in the land surface. Locally the sand has been heaped into low ridges and hills which in certain instances were controlling factors in determining the courses of streams. The anomalous course of St. Marys River is probably due to obstructing sand ridges.
As may be inferred from the lithologic description given above, little can be said regarding the structure of this formation. It conforms to the low seaward slope of the Okefenokee Plain and varies il}. elevation from 60 to 125 feet above sea-level.

LOCAL DETAILS

Surficial sands.-Gray, yellow, and brownish to almost black

sand, reaching a thickness of 20 feet or more, occurs in and on the

borders of Okefenokee Swamp.

The sands are prominent at Folkston; at the surface they are

gray, or in places almost white, becoming yellow at depths. A

high, sand-covered scarp occurs a short distance east of Folkston and

borders St. Marys and Satilla rivers on the west. Fine-grained,

sandy clay or mud, which may be an Okefenokee Pleistocene deposit,

underlies a broad flat through which Spanish Creek flows.

East of Waycross, near the 42d mile-post on the Atlantic Coast

Line Railroad, cuts on either side of Big Creek expose 10 or 15

feet of brownish sand showing stratification lines. The color is due

f

to organic matter.

Heavy beds of gray sand occur at vVaynesville, Wayne County,

which is on the scarp between the first and second Pleistocene ter-

races. A considerable area in southeastern Wayne County and

eastern Pierce County forms a flat, swampy, palmetto and pine

covered plain, over which the gray sands ha.ve a thickness of only

three or four feet.

Gray sands are conspicuous on the eastern edge of the plain at

J\llount Pleasant in vVayne County, and similar sands occur be-

tween Jesup and Altamaha River in the same county. At Ludowici,

l-iberty County, the sands covering the plain are gray to almost

white, and of small thickness. This pine-clad sand plain seems to

428

GEOLOGY OF THE COASTAL PLAIN

merge gradually to the northwestward into the dry, rolling, wiregrass, sandhill region covered with a scattered tree growth, which surrounds Glenville, in Tattnall County. Gray sands are conspicuous on the eastern edge of the plain at Walthourville in the same county.
The sand-covered Okefenokee Plain extends northeastward from Ludowici, through Bryan and Effingham counties, to Savannah River. In Bryan County the surface gray sands and the typical topography of the plain are finely exhibited along the Seaboard Air Line Railway between Ellabell and Groveland. Here the western limit of the plain is on the west side of Cannoochee River, between Groveland and Daisy.
Deposits beneath the surficial sands.-At numerous places within the area covered by this plain there are, beneath the surface sands, deposits of sand and clay the ages of which are more or less problematic. Some of these deposits probably belong to the Okefenokee formation. Occurrences of such materials, concerning the Pleistocene age of which but little doubt exists, are described or referred to below.
The sands and clays overlying the Charlton formation in the higher bluffs on St. Marys River, described on pages 392-400 of this report, are tentatively referred to this formation.
In a cut on the Southern Railway, three miles east of Jesup, a coarse, quartz gravel bed, which may belong to this division of the Pleistocene, is exposed.
Sands and clays, probably referable to the Okefenokee formation, underly the surface sands at brickyards near Waynesville and Odessa, Wayne County. Unconformities, the significance of which could not be determined appear in these ~ections and it may be that both the Okefenokee and Altarnaha formations are represented.
Red and gray, argillaceous sands probably belonging to the Okefenokee formation, appear in bluffs of Savannah River at Frying Pan Landing, Gaffney Landing, and at Ebenezer, Effingham County.
Certain deposits, described in the chapter on the Altamaha formaa tion and tentatively referred to that terrane, may eventually prove to be of Pleistocene age and referable to this formation.
FLUVIATILE TERRACE DEPOSITS
Bordering the large rivers of the Coastal Plain of Georgia are remnants of a plain, higher than the "second bottoms" or Satilla
Plain, and 50 to 200 feet lower than the general upland of the re-
gion. It is believed that the deposits laid down on this plain are

PLEISTOOENE

42~

contemporaneous with the Okefenokee coastal deposits. while the coastal portion o the Okefenokee terrace plain was being cut and the gray sands and other deposits were being laid down upon it, the terraces bordering the present river valleys, and their accompanying deposits, were being ormed,-either by the waves along the borders o reentrant estuaries, or by the meandering o the rivers in the parts o the valleys not submerged. The river terraces coalesce with the coastal terrace.
The river terrace plains lie 50 to 125 feet above the present rivers. Immediately subsequent to their ormation the fluviatile portions of the Okefenokee plain filled the valleys rom side to side, having widths varying rom one to ten miles; into these ancient plains the rivers have intrenched themselves, forming younger plains at two lower levels,--one the Satilla plain, and the other the Recent flood plain. The cutting o these younger plains has resulted in the destruction o all but remnants o the original Okefenokee plain.
The Okefenokee fluviatile deposits overlie in turn all the older Coastal Plain formations, rom the Cretaceous to the Pliocene. The materials have been derived in part, perhaps chiefly, rom these older formations, and in part rom the Piedmont Plateau region to the northward o the Coastal Plain. On account o lithologic similarity it is sometimes difficult to distinguish between the terrace deposits and the underlying older formations. However, in most cases a gravel bed is present at the base o the terrace deposits, and unconformable relations to the older deposits appear wherever there are clean cut exposures. It is probable that in the past some o these deposits have been confused with the Altamaha ormation as has been pointed out in the discussion o the Lafayette formation.
The deposits consist chiefly o red, argillaceous sands, in places pebbly, and ,coarse gravels. There are but few clay beds and the ormation lacks the distinctive alluvial character o the lower terrace and flood plain deposits. Along some o the streams a gray, incoherent, rather pure sand seems to be the only deposit. Near the Fall Line the deposits show clearly that they have been derived in large part rom the crystalline rocks o the Piedmont region, but farther south the Coastal Plain formations have contributed a major portion o the materials. Along Withlacoochee, Allapaha, and Ocklockonee rivers the detritus has been derived entirely rom the Coastal Plain formations. The ormation is usually unconsolidated but in a few places there are local beds o gravel cemented by iron oxide. The pebbles are chiefly quartz and quartzite, but a subordinate percentage are limestone, flint, and limonite.
At a number o localities on the Okefenokee plain there are sur-

430

GEOLOGY OF THE COASTAL PLAIN

ficial, brown-gray, loose, incoherent sands differing in their physical appearance and lithologic characters from the red loams and gravels forming the terrace deposits, and resembling closely the gray sands of the upland. Conspicuous accumulations of such sands were noted at :.Montezuma, Bainbridge, Fort Gaines, Dublin, and Lumber City. Some of these deposits are in the form of hills and are probably of wind-dune origin; they may have been formed subsequent to the elevation of the terrace plain. At other localities the gray sands appear to be water-laid sediments which rest directly upon the older formations, forming a thin uniform mantle over the plain.
The formation is thin, not exceeding 50 feet at any place, and nsually much less than 20 feet. The greatest thickness was noted near the Fall Line.
Except for fragments of silicified wood found at Fort Gaines, and fossils in limestone and flint pebbles derived from the underlying Tertiary beds, no fossils are known in this formation.
The deposits are confined to comparatively level plains paralJeling the riYers. The plains were originally one to 10 miles in width, but the deposits have been so largely removed by subsequent erosion that their total area is relatively small. They are confined principally to the courses of Chattahoochee, Flint, Ocmulgee, Oconee, Altamaha, Ogeechee, Savannah, Ocklockonee, \Vithlacoochee, Little, and Allapaha rivers.
At a few localities the terrace plain forms a conspicuous topographic feature. The physiography of the terrace is illustrated in a profile accompanying this report (See fig. 2, p. 37). The business portion of Macon, a part of the residence portion of Columbus, the cities of Fort Gaines, Albany, Lumber City, and parts of Augnsta are built on this terrace.
In detail the surface of the terrace is nearly level, the only undulations being due to sand heaps. The vegetation is more lnxnriant and the soil generally more fertile than on the inte,rstream uplands.
The approximate elevations of the second, or Okefenokee terrace plain, above sea-level at the Fall Line are:

Augusta ....... . Milledgeville . . . . . . Macon . . . . . . . . . Flint River at Fall line . Columbus ....... .

River. Terrace Plain.

0 98

200

. 215

290

. 279

355

. 320 ? 380 ?

. 190

300 to 325

From the Fall Line there is a gradual descent, until the river ter raceR merge into the coastal sand plains bordering the sea coast.

PLEISTOCENE

431

LOCAL DETAILS
Chattahoochee River.-Good exposures of the Okefenokee formation occur in the valley of the Chattahoochee at Columbus, and Omaha, Ga., at Eufaula, Ala., Fort Gaines, and at Columbia, Ala.
At Columbus, :M:uscogee County, the deposits lie on a terrace approximately 100 to 125 feet above the river. They consist of bright red, highly ferruginous, clayey sands, and gravel composed of large, well-rounded quartz pebbles or cobbles. The formation is exposed at Rose Hill, Ga., and in Phoenix, and Girard, on the Alabama side of the river. It rests unconformably upon the Cretaceous and Crystalline rocks. The deposits do not exceed 30 or 40 feet in thickness.
In the vicinity of Eufaula, Barbour County, Ala., the second terrace deposits appear in a bluff of Chattahoochee River, and form a level plain lying about 100 feet abme the river. Upon this plain the greater part of the city of Eufaula is built. The formation rests unconformably upon the black clay-marls of the Ripley formation. The surface materials are massive, highly ferruginous, clayey sands, slightly hardened by atmospheric agencies, resting upon heavy beds of grawl. The gravels are made up chiefly of quartz pebbles. About one mile southeast of Georgetown, Quitman County, Ga., the gravels have been mined in a pit near the Central of Georgia Railway. Here the deposits are a heterogeneous mixture of gravel and red sand, in places indurated to such an extent as to require blasting. About 15 feet is exposed in the pit. The pebbles are small and consist chiefly <) vein quartz material.
At Fort Gaines, Clay County, the second terrrace deposits consist principally of coarse, red, clayey sands with quartz pebbles at the base. They rest upon Eocene strata. A thickness of 25 feet was noted in this vicinity. In places large limestone fragments, evidently derived from the Midway formation (Eocene), occur in the base of the deposits. The pebbles are composed chiefly of subangular quartz; they are poorly stratified, being arranged in oblique lines and showing crossbedding. Good exposures occur at the old Brown Mill, one mile north of town. Fragments of silicified wood were noted which probably came from this formation. In this vicinity loose, structureless, gray sands also appear on the terrace plain.
At Columbia, Ala., and vicinity, the deposits consist of highly ferruginous, red, clayey sands with scatt:ered small pebbles. The sands have a distinctive bright red appearance, and, upon exposure to the atmosphere, harden in a peculiar manner. The sands form a plain about 100 feet above the river level upon which the town of Columbia is built.

432

GEOLOGY OF THE COASTAL PLAIN

Flint River.-The deposits along Flint River lie 50 or 60 feet above the river and consist of coarse, red sands and gravels. The gravels, which consist of small pebbles, form the lesser part of the deposits. The sands contain some disseminated clay, and when weathered present ~ mottled appearance. li covering of gray sand is conspicuous over the second terrace from the vicinity of Newton southward; the plain here reaches a greater width than along any of the

rivers. The upper part of Red Bluff on the west side of the river, seven miles north of Bainbridge, presents an exposure of Okefenokee

sand lying unconformably upon a mass of residual flint and clay de-

rived from the Vicksburg and Chattahoochee formations. The deposits vary from 6 to 29 feet in thickness; at the base they consist of

coarse sands and small quartz pebbles with a few limestone and flint

fragments; the upper part is composed of red, massive sand with sufficient clay to produce a mottled effect when weathered. On the west

side of the river, and extending three or four miles northward from Bainbridge, is a conspicuous development of wind-blown sand upon the second terrace.

Ocmulgee River.-Along Ocmulgee River deposits were recognized at Macon, Lumber City, and other points. At Macon they occur on a terrace 60 to 75 feet above the river, and form the plain on which

the business section of Macon is built. They consist of coarse quartz gravels and red, clayey sands containing fragments of siliceous lim-

onite. The deposits are kaolinic in places, the source of the kaolin being in part the crystalline rocks which outcrop in the valley just to

the north of the city, and in part the underlying Lower Cretaceous deposits. The beds are heterogeneous, show very little sorting, and pre~ent evidence of rapid deposition. At one point in a cut of the

Georgia Southern and Florida Railway, near H. Stevens Sons' Company's sewer-pipe plant, a bed' of sandstone and conglomerate is prominent. The terrace deposit is easily distingu,ished from the underlying Cretaceous materials by its darker color and its coarser texture. Its thickness can hardly be more than 20 or 25 feet. An ex-

posure showing the relations between the Cretaceous materials and the terrace deposits occurs in the bluff a few hundred yards south of

the plant of the Cherokee Brick Company; white, micaceous, kaolinic sand is overlain unconformably by 15 feet of crossbedded, vari-colored sand and gravel. Lying from 150 to 200 feet above the river are

beds of gravel and red, argillaceous sands similar to those on the second terrace, but there is reason to believe that these are remnants

of overlapping Eocene deposits.

'

The terraces are inconspicuous at Hawkinsville and Abbeville and

<'xposures are poor. The formation seems to consi&t of red sands

PLEISTOCENE

433

>vith suoordinate amounts of gravel. The plain lies about 60 feet aoove the river and is covered with loose, gray sand.
At Lumber City the Okefenokee terrace is present as a well developed plain about one mile wide on the north side of the river. The terrace deposits are exposed in the upper part of the river bluff. The materials are coarse, gray and red, pebbly sands with coarse quartz pebbles at the base. Among the pebbles were noted fragments of limestone derived from adjacent older formations. The formation probably does not exceed 20 feet in thickness; the surface of the plain lies 40 to 50 feet above the river. The Okefenokee plain i5' herP en\ered in part by deposits of yellowish, incoherent sand heaped up, in places, probably by wind action.
Savannah River.-The Pleistocenr. terraces are well developed at Augusta, hut there are no sharp demarcations between the deposits on the second terrace and those on the adjacent upland. On the Carolina side at 80 to 100 feet abme the river, bright red, ferruginous sand overlies, unconformably, Cretaceous strata and weathered schists, but exposures of red san<l probably of Eocene age but of sim ilar lithologic appearance occur in the slopes to an elevation of 200 feet above the river. A mantle of loose, gray sand, slightly tinged with red, also appears on the slopes between the E;econd terrace and the adjacent upland. On the Georgia side near Monte Sano a bed of red, clayey sand containing scattered quartz pebbles and fragments of siliceous limonite was observed lying unconformably upon arkosic sands and clays of the Lower Cretaceous. On account of its lithologic character and topographic position the deposit is considered referable to the Okefenokee formation. These also. resemble red sands on the~ upland at Monte Sano, which probably correspond to the supposed Eocene sands on the upland east of Augusta in South Carolina.
Along the lower course of Savannah River the terrace deposits 1ie fiO to 60 feet above the river, and consist of gray, brown, and red, almost structureless, unconsolidated sands, and beds of gravel made up of quartz pebbles. The deposits are thin and not conspicuom::.
Ogeechee River.-Second terrace deposits appear along Ogeechee River but there are few exposures. They consist of a few feet of red sandy loam, often pebbly, overlain by a thin veneer of gray sand. The plain is 30 to 40 feet above the swamp level. The second terrace is w,en defined at Millen; the surface is 30 or 40 feet above the river; here the terrace deposit consists of red, clayey sand containing small. angular, quartz pebbles.
Other rivers.-Along Withlacoochee, Little Allapaha, and Oek lockonee rivers, the Okefenokee terrace deposits consist chiefly of non-

434

GEOLOGY OF THE COASTAL PLAIN

pebbly sands, clay being almost entirely absent. Tlie sands .are brown or gray, often pure white, and are generally coarse and subangulac. The terraces lies about 40 feet abm'e the rivers. The sand deposits average about 10 feet in thickness. They are unconsolidated and massive, except at a few points where pebbles and faint stratification lines were observed near the contact with the older formations. This .sand forms level plains which may reach two or three miles in width. The predominance of sand on these terraces is explained by the fact that the above mentioned rivers have their sources within the Coastal Plain and traverse only older formations consisting predominantly of sand.

SATILLA FORMATION
The name Satilla is derived from Satilla River, Ga., and is applied to the latest Pleistocene deposits of the State. These deposits are typically developed along either side of Satilla River in Camden and Charlton counties. The shore-Jine during this submergence was parallel to that of the present Atlantic coast, but 20 to 30 miles farther inland. The greater parts of Camden, Glynn, and Chatham counties, all of Mcintosh County, the southern part of Bryan County, and the eastern part of Liberty County were submerged, while the valleys of the larger rivers wer.e inundated as far as the Fall Line. There were thus two types of deposits formed, coastal marine deposits and :fluviatile or river terrace deposits. The two types will be described separately.
COASTAL TERRACEi DEPOSITS
The coastal deposits lie upon a wave-cut terrace which extends 20 to 30 miles back from the present ocean at elevations of 15 to 40 feet above sea-level. The western limit of this terrace or plain is marked by the high sand ridge east of Folkston, Charlton County, and by the escarpment at vVaynesville and Mount Pleasant, Wayne County, and at W althoursville, Liberty County. North of Liberty County the escarpment is not so pronounced as to the southward, and owing to the lack of topographic maps has not been traced in detail. However, it probably passes close to Clyde, Bryan Connty, Meldrim, Effingham County, and Meinhard, Chatham Count,\' This terrace is in this report, referred to as the "first marine terrace" or "first Pleistocene plain," and is not to be confused with the Recent analogous plain now in process of formation which is represented by sand beaches and tide marshes.
The deposits on the Satilla plain rest unconformably upon Pliocene or 11iocene strata, concealing the latter from view, except where ex

PLEISTOCENE

435

posed along stream bluffs and banks. No sharp distinction can be drawn between the latest Pleistocene and the Recent deposits.
The relative age of the formation with respect to the older Okefenokee formation is determined by its topographic position and not by its stratigraphic sequence or paleontologi<' widence.
The formation consists of greenish and bluish, marine clays; gray, white, and yellow sands; and thin layers of gravel. None of the deposits are consolidated.
The clays are fine-textured, and appear to have been muds deposited in lagoons or tidal marshes. They are calcareous in places and contain oyster shells and white calcareous nodules. They also contain organic remains in the form of disseminated, decayed vegetation, stumps of trees and bones of animals. Gypsum crystals were noted in deposits at Savannah and at Colerain Bluff on St. Marys River in Camden County. The clays are usually massive and show few traces of lamination or bedding. They are underlain by sands and often by thin beds of well-rounded quartz pebbles, apparently of beach origin. The sands cover the greater part of the plain and form bluffs on the coast. At the surface they are gray or pure white, becoming yellowish, brownish, or even black at depths, the color being due to iron oxide and disseminated organic matter. They are composed almost entirely of sharp, angular, quartz grains, and are, perhaps, on the whole, finer than the gray, surficial sands of the higher plains. A small amount of mica and black sand, magnetite, ilmenite, and other black, silicate minerals were noted. They show evidences of stratification and crossbedding, and contain shells or prints of shells. In a few places the sands are slightly indurated by an iron oxide cement, as at the bluff near Crescent, Mcintosh County.
The sands and clays are closely associated and are contemporaneous deposits.
The maximum thickness of the deposits is perhaps not more than 50 feet and the average not more than 15 feet. A thickness of 22 feet of clay has been observed near Savannah and 20 feet of sand appears at Crescent. At Rose Bluff, Fla., opposite St. Marys, the bluff, which at low tide is 45 feet high, exposes Pleistocene strata referable to this formation from base to top.
The formation is fossiliferous and in this respect is in contrast to the older and topographically higher Okefenokee formation. Shells, mostly living species, are common in places; remains of mammals, megatherium, tapir, horse, mammoth, beaver, deer, and cetacea occur; sharks' teeth occur at certain localities, and remains of a
species of crocodile is found. Bu.ried stumps are found in many

436

GEOLOGY OF THE COASTAL PLAIN

places, but no other plant remains of paleontologic value have been discovered.
A collection of bones and teeth made from the dredging at, Brunswick were studied by J\fr. J. W. Gidley, of the Smithsonian Institution. He says:

"The materials from Brunswick, Ga., consist for the most part of fossil fragments of various mammals and fishes representing species of early Pleistocene age. The sharks teeth, however, probably represent Eocene and Miocene species. The recognizable genera and species are as follows:

Mammals.
Fishes. Reptiles.

Equus fraternus Leidy Equus ? complicatus Leidy Equus ? tau Owen (or more probably an undescribed species) Mammut floridanum (Leidy) Physeter ? vetus Leidy or Physeterula ? neolassicus Megatherium sp. probably M. americanum Castoroides ohioticus Bison ? bison Linn. A Cervuline, probably belonging to the genus Cervus 'l'apirus haysii Leidy
Sharks-several species of the genera Carcharodon Galeocerdo and Lamna Sting-ray-Pastinaca sp. The sharks teeth represent several species of the genera
Carcharodon, Galeocerdo, and Lamna.
Crocodilus sp.

The "Eocene and Miocene species" may be detrital material redeposited during the Pleistocene.
A collection of shells was made at Rose Bluff, Fla., opposite St. Marys, Camden County, from which the following forms 'were determined by Dr. Vaughan.

List of fossils from Rose Bluff, Fla., opposite to and four miles southwest of 8t. Marys, Ga.

Mulinia Iateralis (Say) Terebra dislocata Say Olivella mutica Say Nassa acuta Say Turbonilla sp. Neverita duplicata Say Natica pusi!la Say Sigaretus perspectivus Say Nucula proxima Say Area incongrua Say Ostrea virginica Gmel.

Anomia sumplex Orb. Phacoides multilineatus (T. & H.) Divaricella quadrisulcata Orb. Cardium robustum Solander Tellina (Angulus) sayi Deshayes Strigilla flexuosa Say Donax fossor Say Donax variabilis Say ? young Ervilia concentrica Gould Labiosa canaliculata Say

Sir Charles Lyell' visited several localities along the coast of

'Travels in North America.

PLEISTOCENE

437

Georgia. He notes finding the tooth of a M ylodon and the grinder of a mastodon at Heyners Bridge, 12 miles south of Savannah; he also mentions finding remains of M egatherium in the old Brunswick canal and on Skidaway Island. Lyell sugge'sts that the deposits are of fluvio-marine origin and that the bones of the mammals were earried down by streams.
Oyster shells are found in the clay deposits west of Savannah, in clay in the western part of Glynn County, in the clay terrace bordering St. Marys River, and at other localities. Large bones of mammals have been found at Whiteoak, Camden County.
The time which has elapsed since the emergence of the Satilla plain from below sea-level has been relatively short and erosion has as yet affected the appearance of the surface but slightly. The plain is very flat and there are great stretches of swamp land. In places on the plain there are low ridges of sand, probably of beach and winJ-dune origin, although some such ridges may have existed as banks or islands previous to the emergence of the plain above sealevel. The clay flats probably represent the sites of old marshes and shallow estuaries and straits.
If the coast region were uplifted 15 or 20 feet above its present elevation, a plain now submerged beneath the ocean waters would appear as an emerged terrace lying east of and parallel to the Satilla terrace, and separated from it by an escarpment. This plain would be ana1ogom; to the Satil1a plain in all its essential features.

LOCAL DETAILS
Observations have been made at the following localities:
Savannah, Chatham County.-A thick 'deposit of fine-grained, plastic clay occurs near the Seaboard Air Line Railway, three miles west of Savannah. It is at a lower elevation than the land both to the east and west, and has the appearance of having been deposited in an ancient marsh or lagoon. The clay rests upon red sand and clay of an entirely different lithologic appearance, the age of which is problematical.
At a point one and one-half miles west of this locality, and near the railroad, the clay, as determined by an auger boring, reaches a thickness of nine feet and is underlain by three feet of coarse gravel and sand. The clay is fine-grained, plastic, and contains small lime nodules and fragments of oyster shells.
In a railroad cut seven and one-half miles west of Savannah is a yellowish, stiff, fine-grained clay containing oyster shells. The cut i::; three feet deep and affords only a poor exposure.

438

GEOLOGY OF THE COASTAL PLAIN

Near Pooler a clay deposit, which is being used in the manufacture of brick, contains oyster shells; buried tree stumps are also reported. The oyster appears to be Ostrea virginica, a species at present inhabiting Atlantic Coast waters. The clay lies in swampy, wet tracts and is three to eight feet thick.
At Wheat Hill on the Seaboard Air Line Railway, five miles north of Savannah, 10 feet of bluish, sticky mud containing oyster shells was found by boring.
At the Isle of Hope a bluff eight feet high exposes brownish sand resembling burned sugar; the sand shows crossbedding, is slightly indurated, and contains a few scattered shells.
A large part of the city of Savannah is built on a high, Pleistocene sand bluff or sand hill, surrounded on a1l sides by lower land. This bluff rises about 30 or 35 feet above the level of Savannah River. The escarpment between this sand deposit and the more recently formed marsh or tide land is easily distinguished near the Tybee Island station of the Central of Georgia Railway in the eastern part of the city.
A bluff on Savannah River a short distance above "The Hermitage" is about eight feet high and shows the following section:

Section in bluff on Savannah River.

Satilla formation.

3. White or gray, incoherent, quartz sand . . . . . }

2. Bluish, sandy clay, weathers reddish . . . . .

(Unconformity.)

Age (?)

/

1. Gray sand containing white or drab clay laminae

Feet 6 2

Layer No. 1 may represent a formation older than the Satilla formation. No fossils were found. Northward from this point the marine terrace deposits merge into the fluvio-estuarine or fluviatile deposits of the lowest terrace bordering Savannah River.
Southward from Chatham County, through Bryan, Liberty, and Mcintosh counties, the surface is covered largely by gray or white sands, with subordin~te areas of clays which contain oyster shells.

Crescent, Mcintosh County.-A picturesque sand bluff 20 feet high occurs at the mouth of Sapelo River near Crescent. The sand is gray or white at the surface and yellow or brownish at depths; ir is sufficiently indurated to produce a nearly vertical cliff, and large wave-worn boulders of the material lie along the base. The induration is probably due to iron oxide cement and the dark color is in part at least due to organic matter. Only faint evidence of stratification was noted. No fossils were discovered.

PLEISTOCEXE

439

A red, argillaceous sand of problematic age was seen along the railroad about three miles west of Crescent.
Glynn County.-The Satilla formation in the western part of Glynn County is representBd by clays underlying "clay flats" and swamps. The swamp areas probably are the sites of old sounds, marshes and drowned river courses in which chiefly muds were deposited. The surface of the eastern part of the county is mainly sand.
In the bed of a small creek on the Livingston plantation, 18 miles west of Brunswick, the Pleistocene consists of a few feet of greenishgray, argillaceous sand containing fragments of bones and teeth.
Remains of mammals' ~were found in the excavations for the Brunswick canal in 1838 and 1839, and oyster shells are found in the clay deposits in the western part of the county. Fossil remains from the Pleistocene at Brunswick, obtained by dredging, have been described on page 436.
A short distance west of Bladen and Everett City the rise from the swampy flats of the first terrace to the sandy pine plain of the second terrace may be easily observed without the aid of topographic maps.
Camden County, Satilla and St. Marys Rivers.-At Whiteoak. near the station, a few feet of clay appears just above the level of high tide. The clay is an olive green in color, very sandy, and contains white, limy concretions. Bones of vertebrates have been found. A clay flat extends northward from Whiteoak to Bladen.
Pleistocene clay and sand deposits occur along Satilla River. On the west side of the river at Burnt Fort is a clay flat or terrace nearly four miles wide. The clay of this terrace is greenish in color and stiff, and contains calcareous nodules. The surface of the flat is 10 or 15 feet above the river. The clay overlies a soft, argillaceous limestone and an older sandy clay which are exposed in the river bank at low tide.
At Owens Ferry farther down the river the Satilla formation appears in a bluff about eight feet high. It consists of sand and bluish, sandy clay, becoming coarse-grained, and containing a few scattered pebbles at the base. It overlies a fossiliferous, calcareous sand and sa;:tdstone which are tentatively referred to the Miocene.
Over most of the southeastern part of Camden County the only material exposed is gray or yellow, unconsolidated sand.
There are a number of low sea bluffs near St. Marys in which sand only is exposed. Point Peter Bluff, four miles northeast of St.
'White, George, Statistics of Georgia, 1849, p. 283.

440

GEOLOGY OF THE COASTAL PLAIN

Marys, is 10 or 12 feet high; the upper part of the bluff is com-

posed of gray, almost white, incoherent sand, and the lower part is

brown, chocolate, or almost black, slightly indurated sand.

Miller Bluff on North River, five miles north of St. Marys, is 15

feet high at low tide and is likewise composed of fine sand. The

lower part of the bluff is brown or umber in color, and slightly in-

durated.

A collection of fossils was made at Rose Bluff, Fla., opposite to

and four miles southwest of St. Marys. The bluff is composed en-

tirely of sand.



Section of Rosr Bluff, opposite to and four miles southwest of St. Marys.

Satilla formation.
~- At the top, gray Qr white, loose sand . . . . . . 7. Brownish sand, color due to orgamc matter and
iron; compact enough to form large tide-washed boulders . . . . . . . . . . . . . 6. Greenish, sandy clay . . . . . . . . 5. Brown sand contains scattered shells 4. Bluish, stick mud . . . . . . . . . 3. Greenish clay and sand . . . . . . 2. Friable sand, full of shells . . . . . 1. Sand and greenish clay at. low tide .

Feet.
3 or 4
12 4 5 2 4 5 9

The above section was nta<le at a spring, the only point where fossils were found.
A similar blnff, Reeds Bluff, about two miles aboYe Rose Bluff, is described by Sellards.' A bed of oyster shells occurs here.

The Satilla formation is exposed at Orange and Chalk bluffs and other localities on St. Marys River, where the deposits underly flat terraces. The best exposures are on the Florida side of the river.
At Orange Bluff, two miles aboYe Kings Ferry, Fla., the formation i.s a stiff, greenish clay overlying a white marl unconformably. The contact bet"een the clay and the marl (Charlton formation) is marked by a line of well-rounded quartz pebbles, some as large as an inch in diameter. The formation has a thickness of four to six feet in the bluff; a few fragmentary oyster shells were noted in the clay.
Stiff clay of the Satilla formation was also noted at Chalk Bluff, one-half mile above the preceding.
At Sawpit Landing, two miles above the ferry at Traders Hill, Charlton County, a similar greenish clay forming a flat terrace is exposed in a low bluff to a thickness of three feet. For a section of this bluff see page 398.
1Sellard,, K II .. Tllird Ann. ll~pt .. Fl~. GPol. Surv., 1910, p. 127.

GEOLOGY OJ' 7'HE COAS7'A.L PLAIN OP GEORGTA.

Pf,ATE XXIX .

.L DEPOSIT OF PURE WHITE A:\'D USED I:'< THE X!AN l?ACTURE o rr GLAS
PROBABLY BELO r GI.'IG TO THE OKEFENOKEE l!'OR~IATION. TWO MILES NOH'rHEA 'T OF LU~IBER CITY. TELFAIR COU.'ITY.
B. BEARDS BLUFF. ALTAi\IAHA RIVER, TATTNALL COUNTY. SHOWI:\'G PROMINENT CLAY LAYER IN SA'l'ILLA FORX!ATION, OVERLAIN BY LOOSE SAND.

PLEISTOCENE

441

FLUVIATILE TERRACE DEPOSITS
The fluviatile deposits of this period form low terraces along the larger rivers of the Coastal Plain. They consist of unconsolidated sands, clays, and gravels which merge coastward into the marine or fluvio-marine deposits described on preceding pages.
The river terraces of the Satilla formation are comparatively flat plains, from 10 or 15 to 40 or 50 feet above the rivers, and vary in width from 300 or 400 yards to an original width of 8 or 10 miles. They extend from the Fall Line southward and eventually merge into the marine terrace plain of the same formation. The greatest width is attained along the lower course of Savannah River, but the river is cutting into this original terrace and forming the Recent alluvium. The topographic position of the terrace is illustrated in Plate II, B, opposite page 40. A distinction is made between the Satilla terrace and the Recent flood plain.
The Satilla deposits overlie Cretaceous and Tertiary formations unconformably. They vary in elevation above sea-level from about 300 feet at the Fall Line to 20 or 30 feet where they merge into the coastal deposits. The thickness does not generally exceed 10 or 2() feet, but a thickness of 40 feet is attained in places.
Lithologically, the deposits vary considerably on the different rivers. On the whole they have a distinctly fluviatile or alluvial aspect, consisting of clays, sands, and gravels, generally unconsolidated, and without regular bedding. The materials have been derived in part from the adjacent older Coastal Plain formations, and in part from the Piedmont Plain region to the northward. Sand heaps, probably wind accumulations, were noted at a number of places on this terrace.
The formation contains but little of paleontologic interest. A few mammalian bones were found at the base of the deposits on St. :Marys and Suwanee rivers; a few fragments of silicified wood have also been observed.
Savannah River.-The Satilla plain or terrace bordering the Savannah River was originally a comparatively level plain, two to ten miles in width, which extended entirely across the valley. Into this plain the river has intrenched itself, meandered, and formed a broad, flood plain swamp of Recent age. Throughout the greater part of its course, from about 30 miles below Augusta to Purisburg, S. C., the river banks, exclusive of the high bluffs, expose chiefly the flood plain alluvium of the Recent swamp, the Pleistocene allu>'ium appearing at but a few localities.
At Augusta the deposits reach a thickness of 30 or 40 feet. They

442

GEOLOGY OF THE COASTAL PLAIN

consist of sands, gravels, and lenticular layers of sandy and plastic clays. The clays are used extensively in the manufacture of common building brick. The business portion of Augusta is built upon the plain formed by these deposits.
New Savannah Bluff, 13 miles below Augusta, affords a fine exposure of the formation. The bluff reaches a maximum height of 25 feet; the lower part consists of coarse, crossbedded sand and beds of small pebbles. A large percentage of the pebbles is composed of feldspar; the upper eight feet is red, coarse, harsh sand which contains a small amount of disseminated clay, and is sufficiently compact to form an abrupt face. At the upper end of the bluff there is a thin, non-persistent layer of bluish-white, sandy clay. The material exposed forms a level plain about one mile wide on the Georgia side of the river.
Silver Bluff, 27 miles below Augusta, on the Carolina side, is the most typical Pleistocene bluff exposed on the river. It furnishes an excellent example of a fluviatile or flnvio-estuarine deposit. The materials consist of coarse, crossbedded sands and gravels of a heterogenous character, overlain' by an undulating, massive, and non-laminated sandy clay, and this in turn by red and yellow sands. The pebbles are angular and occur in lenses about three feet thick. None of the beds are indurated: The bluff reaches a height of 22 feet. Opposite, on the Georgia side, the low silty banks of the swamp or Recent flood plain appear.
Other exposures of the Satilla formation occur at Cohens Bluff Landing, S. C. ; Poor Robin Landing, Ga. ; Parachuchla, and Purisburg, S. C. At Cohens Bluff, 101 miles above Savannah, a bed of massive, light greenish clay, containing lime nodules is exposed. Its lithologic character indicates that it has been derived in large part from the argillaceous Eocene marls to the northward. At Parachuchla, 55 miles above Savannah, the bluff exposes about 15 feet of structureless, gray, and light buff sand, underlain by two or three feet of mottled, sandy clay. The sand forms an oval hill produced by either wind or current action; the type of deposit is similar to that at Beards Bluff on Altamaha River described on a subsequent page. At Purisburg, S. C., 23 miles above Savannah, the formation appears in a bluff about 12 feet high in which is exposed reddish, sandy clay (color due to weathering), drab, laminated clay, crossbedded sand, and coarse gravel resting unconformably upon Miocene strata. The pebbles, which have a maximum diameter of six inches, indicate a fluviatile or estuarine deposit; the coarseness of the gravel suggests that the material was carried down during floods, or at some stage when there were strong currents.

PLEISTOCENE

443

Ogeechee River.-Along Ogeechee River, dposits of the Satilla formation consisting mainly of sand form a terrace, the upper surface ' of which lies about 10 feet above the river. At Rocky Ford, Screven County, however, clay probably belonging to this formation waS' noted in a terrace which lies about eight feet above the swamp. A conspicuous development of the sand occurs at Eden, Effingham County. The highest part of the sand hill west of Eden is- nearly 20 feet above the swamp.
Ocmulgee and Oconee Rivers.-The Satilla terrace along Ocmulgee and Oconee rivers rises 10 to 20 feet above the river levels. In many places the terrace is swampy, is :mb~ect to overflow, and has the aspect of a Recent flood plain deposit.
Near the Fall Line, clay makes up the greater part of the deposits~ the amount of sand increasing to the southward. The general section at the Fall Line is:
At the surface, sandy loam grading into brownish or yellowish clay with limonitic concretions; then bluish, plastic clay; and at the base, sand and gravel, water-bearing.
Southward the plain is covered at many places with loose, gray sand, and the clays occur as lenticular beds of small extent, or in pockets in the sand. In places the clays are fine-grained, plastic, and contain lime nodules.
AUamaha River.-Along Altamaha River the Satilla formation presents much the same aspect as along Savannah River. The Satilla plain originally had a maximum width of four or five miles; into this plain the Altamaha River has entrenched itself, meandered and formed an extensive Recent flood plain or swamp two to six feet above low water level. The Satilla beds appear in bluffs 10 to 15 feet high. Hillocks of wind-blown sand appear at different places over the terrace plain.
Beards Bluff (see plate XXIX, B), in Tattnall County, 60~ miles below the forks, affords a good example of the fluviatile phase of the formation. The bluff is about 15 feet high and is capped by a dome of fine, gray sand; beneath the surface sand is an undulating layer of bluish, sandy clay, and beneath the latter, forming the base of the bluff, is a coarse, current-bedded sand. The surface sand seems to have been accumulated by wind action: The clay and lower sand were probably reworked from the Altamaha formation. Ohoopee White Bluff, 392 miles below the forks also presents a good section of the Satilla formation. The section is similar to that at Beards Bluff except that the wind-blown surface sand does not appear. A coarsely arenaceous clay bed, which terminates abruptly along the

444

GEOLOGY OF THE COASTAL PLAIN

bluff, appears in the section. The materials as a whole are heterogenous in character and appear to have been deposited by rapid river currents. Buckhorn, Red, and Town Bluffs expose materials, mainly sand, referable to this formation.
Flint River.-Near the Fall Line the first terrace above the river is broad and swampy, and is underlain mainly by brownish and bluish plastic clays. From Oakfield to Bainbridge the Satilla terrace forms a narrow plain, 15 to 20 feet above the river. The terrace deposits are exposed at a number of places. The general section is as follows: At the surface-loose, gray sand; then undulating layers and pockets of clay; at the basec--(;6arse, heterogenous, crossbedded sand with lesser amounts of graYel.
Chattahoochee River.-The best development of the Satilla terrace occurs along the Chattahoochee RiveJr. Th.e river has cut a narrow trench about 40 feet deep in the nearly level plain, exposing unconsolidated sands, clays, and gravels of the Satilla formation, resting upon strata of Tertiary and Cretaceous ages. Conditions differ from those on SaYannah and Altamaha riYers in that there is scarcely any swamp bordering the river, and the plain is on the whole higher above the river level; tributary streams enter the river through narrow trenches or gorges and not through swamps, as on Savannah and Altamaha rivers.
Fine developments of the terrace may be seen at Columbus, Omaha, Georgetown, opposite Eufaula, Ala., and at Fort Gaines. This terrace plain reaches a maximum width of three miles but the average is not perhaps more than one or one and one-half miles.
Opposite Columbus the terrace material consists in part of brownish or yellowish, structureless loam presenting somewhat the appearance of loess. The Satilla terrace forms a level plain, approximately one mile wide and about 50 feet above the river, on which a part of the city of Columbus is built.
The deposits consist predominantly of sand; clay layers occur in undula.ting beds of variable thickness and in pockets enclosed by sand, and graYel beds are common at the base of the terrace deposit. The crossbedding and the general heterogeneous character of the materials indicate rapid changes in the conditions of deposition.
Southward from Columbus the deposits begin to show evidence of being derived in part from the Coastal Plain formations.
Other rivers.-The deposits of this formation bordering the Ocklockonee, \Vithlacoochee, Allapaha, Suwanee, and St. :Marys rivers are composed almost entirely of gray or white sand and gravel, with subordinate clay beds in a few places. The rivers have cut narrow

RECENT

445

trenches resembling canals in the sandy terrace plains of the for-

mation. The terrace plains reach a width of one-half mile or more,.

though usually they are much narrower; their surfaces lie about 8 to 15 feet above the rivers.

Along Withlacoochee River, east of Quitman, the Satilla terrace

is about 20 feet above the river and is about one-half mile wide. The

sand is pure white in places and might be suitable for use in the manufacture of bottle glass. It is usually fine at the surface but becomes

coarser with depth, often showing crossbedding at the base.

On the Allapaha, two miles east of Milltown, the terrace is well developed and is about 15 feet above the river. The section at the

wagon bridge is as follows :

Section at wagon bridge two miles east of Milltown.

Feet.

Pleistocene.

Satilla formation.

3. Brownish or chocolate-colored sand, gray or white

over the surface of the plain . . . . . . . . .

5

2. Brown or yellow, coarse sanu, quartz, and quartz

ite pebbles; also contains small white pebbles of

phosphate . . . . . . . . . . . . . . . . . .

2

(Unconformity.)

Oligocene.

Alum Bluff formation.

1. Greenish; laminated, sandy clay . . . . .

.. S

This terrace forms a clay flat west of Stockton.

At Statenville, Echols County, the Satilla formation consists of

very pure, gray or white, quartz sand, in places coarse-grained. The terrace lies about 20 feet above the river.
At Bony Bluff, nine miles southwest of F'argo, large, blackened

bones and fragments of silicified wood are found in a bed supposed to lie at the base of the formation.

On St. Marys River from near St. George up the valley the deposits of the formation may be considered of fluviatile or fluvio-

estuarine origin. They form a flat sand terrace about 12 feet above

the river. At Stokes F'erry, 11 miles south of St. George, the basal

part of the formation consists of pebbly sand in which are embedded

fragments of bones and teeth, and roots of trees.

RECENT

The Recent deposits, or those formed since the close of the Pleisto-

cene or the uplift of the Satilla or hltest Pleistocene terrace, and now

in the process of formation, consist of: (1) marsh and tide-swamp

\

muds; (2) beach sand and dunes; (3) river flood plain deposits;

(4) interstream swamp deposits; ( 5) certllin terrigenous deposits.

semi-alluvial in character.

446

GEOLOGY OF THE COASTAL PLAIN

The processes by which the Satilla terrace, with its accompanying deposits, was formed are being repeated at the present time along the coast. The Recent terrace which is thus being formed is largely submarine. Beach sands are being laid down on the ocean front, while the courses of the streams entering the ocean are drowned and converted into estuaries, and muds are being deposited in the marsh and tide-swamp land. In the absence Of any accurate maps the area of marsh and tide-swamp land along the coast may be roughly estimated at 400 square miles. While observations have not been made at a very large number of localities, the thickness of the Recent deposits in the area inundated by the tides probably does not exceed six feet. The composition of the muds is indicated by the following .analysis of a sample from St. Simons Island, made by Dr. Edgar Everhart from a sample collected by Prof. McCallie.

Analysis of mud from St. Simon Island.

Moisture at 100 C. .

Loss on ignition

Soda, Na, 0 . .

Potash, K,O

Lime, CaO

Magnesia, MgO

Alumina, Al,O, .

.

. . . . . . . . . . . .

Ferric oxide, Fe,03 Titanium dioxide, TiO, . . . . . . . . . . . . . . . . .

Sulphur trioxide, SO, . . . . . . . . . . . . . . . . . .

Phosphorus pentoxide, P,O, . . . . . . . . . . . . . . .

Chlorine, Cl . . . . . . . . . . . . .

Silica, SiO,

4.62 9.94 3.013 1.1:: .40 1.28 13.67 4.86 1.01
.24 2' 1.77 C7.:)5

Total

. . . 100.15

In places the Satilla terrace is separated from the Recent terrace by bluffs 10 to 15 feet high, while at other localities the two merge into each other.
The Recent alluvium along the Coastal Plain streams consists m;ainly of sand, although along the lower courses of Altamaha and Savannah rivers some clay has been deposited. Owing to the comparatively short period that has elapsed since the close of the Pleistocene, deposits of this class are of small extent. Along some of the streams the only Receni deposits are accumulations of sand in the form of bars.
In the southeastern part of the Coastal Plain' of Georgia are numerous swamps ranging in size from one to two acres to tha~ of the immense tract known as Okefenokee Swamp. Peaty accumulations {)r decayed plant matter with more or less silt and sand are being formed in these swamps. In the Okefenokee Swamp peaty accumu-

SURFICIAL SAND

447

lations to the thickness of four feet are reported. Some of the E>'Wamp areas are densely wooded and have been the roosting places of birds for perhaps centuries, and a phosphatic muck is being slowly .formed from their dung and dead bodies.
Sand deltas or plains of semi-alluvial character form another type of Recent deposits. In the northern, hilly part of the Coastal Plain erosion has been very active on account of the loose, unconsolidated character of the formations; and at certain localities, especially where the forests have been cut away, deep gullies have been formed. Every torrential rain moves large quantities of sand which, on acount of over-loading, is deposited along the beds of the small creeks, forming so-called "sand streams," or is spread out at the mouths of gullies forming small subaerial deltas. The best example of this type is at the huge gullies or "caves" west of Lumpkin, Stewart County. A "sand stream" is illustrated in Plate XIV, B.

SURFICIAL GRAY SANDS OF THE UPLAND
Surficial grayish or brownish, incoherent quartz sands cover large portions of the interstream uplands of the Coastal Plain of Georgia at elevation~'>' higher than the Pleistocene terrace plains. On account of the sterility of the soils which these sands produce and their influence on the topography and tree growth, they attract the attention even of perE>'ons who are not interested in problems of geology. The sands are not everywhere of the same origin. Much of the sand is residual and can not be referred to any one geologic period or formation. However, in places there are wind-blown accumulations, and at rare intervals the marks of ~Stratification can be detected. In this report no attempt has been made to sub-divide or to map these sands and a part of this work would, perhaps, more properly fall within the province of a soil survey.
The surficial gray sands are made up almost entirely of crystalline quartz there being at no place sufficient clay to render them coherent. A number of samples were examined microscopically. In addition to the quartz grainE>', small percentages of clay, some limonite and allied iron oxide minerals, and very small amounts of minerals common to igneous rocks such as mica, magnetite, ilmenite, feldspar, ana rutile were detected. The clay content rarely exceeds three per cent; the limonite occurs as a coating over the quartz grains and gives the sand its yellowish or brownish appearance. On the whole, the sand is uniformly fine in texture; in samples tested from several localities 40 to 60 per cent. of each sample passed a 40-mesh sieve; the texture o-f the residual sands at any particular locality depends upon the {'har:wter of the sands in the formations from which they were de-

448

GEOLOGY OF THE COASTAL PLAIN

rived. In all of the more notable deposits the quartz grains are for the most part subangular. In color the sands are dull gray or white at the surface, but at varying depths becomes yellowish or some darker shade; the darker basal sands grade downward into the underlying, unweathered, argillaceous, sandy formations. Pebbles are not common although at a number of localities they have been observed. They consist of t>mall, well rounded to angular, quartz pebbles, and small, brown or black, iron oxide nodules. Slight differences in the character of the sands at various localities have been noted, but on the whole they are uniform in texture, color, and composition, notwithstanding their diversity of origin.
The surficial sands vary in thickness from a few inche~ to a maximum of 30 feet. The greatest thickness of \Vhat appear to be residual sands occurs at the sand-pits near Howard, Taylor County, whel'e the maximum is 20 or 30 feet. At other localities along the Fall Line 10 to 25 feet of sand has been observed, but over much of
n the "sand hill' region, the thickness does not exceed five or six
feet. Over the Altamaha (Lafayette terrane the average depth of the residual sands in place is probably between two and four feet,. but there are local accumulations of sands of torrential or eolian origin reaching a thickness of 10 to 25 feet, In the western part of the Coastal Plain, principally that part underlain by the Vicksburg formation, the gray sands are either absent or very thin. The,y are absent also in scattered smaller areas in other parts of the upland regwn.
The surficial sands are present as a thin mantle over parts of the upland region from the Fall Line on the north to the Florida State line on the south. To the southeastward, within 50 or 75 miles of the Atlantic Coast, they merge' into the lithologically similar sands which cover the Okefenokee terrace plain. The sands are unequally distributed over the upland and are notably absent from certain areas. Their most conspicuous development is in the Fall Line region, chiefly over the area underlain by Lower Cretaceous strata; they are also welL developed over the region underlain by the Altamaha and Alum Bluff formations in the eastern and southeastern parts of the Coastal Plain. Upland areas, where the sands are nearly or entirely absent, are the following: Certain areaS' in Burke, Washington, wilkinson, and Twiggs counties which are underlain by red, ferruginous sands of the Claiborne formation; Rich Hill, Crawford County; the Fort Valley plateau, and the "red lands" in the vicinity of Grovania, Henderson, and Elko in the southern part of Houston County; the northern part of Dooly County; in the vicinity of Americus, and the southern part of Sumter County;

GEOC.OGY OF 'l'IIE COASTAL Pl.d..IN OF GEORGI A..

PLATE XXX.

SURFICIAL SAND

449

large parts of Randolph, Terrell, Dougherty, and other counties west of Flint River; and in the southern parts of Grady, Thomas, and Brooks counties.
The sands, notwithstanding their relatively insignificant thickness, have had a very marked influence upon the topography, vegetation, and settlement of the country. The "sand hills" constitute a well known type of topography in the region of the Fall Line, and throughout that part of the area underlain by the Altamaha (Lafayette ~) formation, popularly known as the ''wire-grass" region. In the latter region the sands are mo~t conspicuous along the streams and particularly along those streams having general north-south courses. It has been commonly noted by the people living in this region that the accumulations of sands are greater on the east or left sides of the streams. Numerous exceptions to this may be found in the Coastal Plain region as a whole, but it is prevailingly true over the "wire-grass" region.. The hills perhaps antedate the present streams and may have governed their courses in part, the western front having acted as a barrier preventing the streams from pushing their courses to the eastward. The most notable examples of this type of sand hills are on the eastern side of Ohoopee River at Reidsville; on Cannoochee River at Stillmore; on Little Ocmulgee River two miles east of Helena and at Lumber City; and on the north side of Satilla River north of Waycross. These hills are well above the level of the streams and the sand is not to be confused with the alluvial sands of lower lervels. The vegetable growth over the sand hills is sparsl:l, consisting mainly of scattered long-leaf pines and stunted oaks, and the soil is poor and unproductive.
The origin of the gray sands which form the "sand hills" and cover the higher interstream areas of the Coastal Plain has been a perplexing problem to geologists and other investigators.
In the few references made by McGee' to these surficial sands he referred them to the "interfluvial phase of the Columbia." Also Spencer; McCallie,' and Veatch' have referred to them in a general way as "Columbia sand." Mr. R. M. Harper' has given interesting descriptions of the E>ands at a number of localities, discussing them from the standpoint of their influence upon the flora of the Coastal Plain.

'The Lafayette formation : Twelfth Ann. Rept., U. S. Geol. Survey, 1890-1891, pt. 1,

pp. 388, 389.

'

2Spencer, J McCal!ie,

.s.Ww., .F,

irst Un

Ann. Rep derground

t

. Progre Waters

ss, of

Georgia Geol. Survey, 1890-1891, Georgia: Georgia Geol. Survey,

pp. 61-71. Bull. No.

15, 1908, p. 2'

clay Depos A. Phytogeob

~ae!orSgika.c:

Georgia h of the

Geol. Survey, Bull. No. Altamaha Grit Region

18, :t909 p. of Georgia:

68. Annals

N.

T.

Acad. Sci., Vol. n, pt. Nov., 1906.

450

GEOLOGY OF THE COASTAL PLAIN

It is reasonably certain that much of the surficial sand is residual from Cretaceous and Tertiary formations, and hence should not be classed as a formation, using this word in a stratigraphic sense. The residual sand varies from one to ten feet in thickness. At many places on the slopes there are accumulations of sands transported by rainwater from higher to lowerr levels. In some cases the redeposited sands appear to rest unconformably upon the underlying strata, this relation being especially apparent where pebbles are presel).t at the base. Such deposits may show a thickness of from five to fifteen feet wher~as the residual sands on the tops of the hills may not be more than two feet. Accumulations of this nature are properly colluvial deposits. The winds may have shifted and redeposited the residual sands in places but there do not appear to be many large deposits due to this cause.
The formations from which the residual, surficial sands are derived are themselves composed chiefly of quartz sand with small percentages of disseminated clay. In the process of weathering the clay is carried away in suspension by rainfall leaving the quartz grains and small amounts of other minerals, such as mica, iron oxides, etc. Wherever the formations underlying the surface are very calcareous, argillaceous, or fe,rruginous, the gray surficial sands are absent.
In addition to the residual and colluvial deposits, there are gray or browish, incoherent sand deposits 10 to 30 feet thick, which lie in belts one~half mile to two miles wide, paralleling certain rivers and creeks; these accumulations appear to be at higher elevations than the fLuviatile terrace deposits of the O~e,fenokee formation. Locally, they exhibit faint stratification lines and in places seem to be sharply separated from the underlying older formations. These facts, together with their peculiar distribution and relatively great thickness are evidence of their non-residual character. Their high elevation precludes the possibility of their having been deposited by existing streams. It is suggested that they may have been heaped up as the result of combined wave and wind action along the shores of early Pleistocene estuaries, or they may have been deposited as alluvium by the rivers occupying the valleys in early Pleistocene time. This type of surficial sand is typically developed along Cannoochee, Ohoopee, LittLe Ocmulgee and Satilla rivers, and appears along other streams throughout the Altamaha upland or "Wiregrass country."
One well known sand deposit,-the sand hills on the east side of Flint RiV'e'r at Albany,-dearly owes its r.resent form to wind deposition, whatever may have been the primaiy origin of the sand.

SURFIOIAL SAND

451

There is some evidence of a sand-coverd, Pleistocene terrace plain higher and older than the Okefenokee plain and perhaps similar in origin, although as yet sufficient proof of its existence has not been obtained to warrant positive statements. Such a plain, if it exists, includes a part of the gray surficial sands here treated under the head of upland sands. (See pp. 424-425.)

LOCAL DETAILS
The more important localities where the surficial sands are developed, are mentioned below, and the topographic positions, lithologic characters, and probable origins of the deposits are indicated.
Fall Line localities.-Extending southward 10 to 20 miles from the &'outhern border of the Piedmont Plain is a belt of land over much of which gray or brownish, incoherent quartz sands form a surficial covering. In a classification of the Coastal Plain from the agricultural standpoint Loughridge1 has described this region as the "Fall Line sand hills." In extent the "sand hills" were said to reach across the State from Augusta to Columbus, covering an area of about 2,950 &"quare miles. The surficial sands over this area are believed to be residual, except along the terraces bordering the rivers, where fluviatile sand deposits of Pleistocene age have been deposited.
Near Hampton Terrace Hotel on the South Carolina side of Savannah River opposite Augusta, the surficial sands are gray or brownish, and mantle the upland plain at an elevation of 225 feet or more above the river; in one exposure, at the base of the gray &"and water-worn, quartz pebbles having a diameter of two or three inches, were observed. These pebbles are unmistakably in the surficial sand and suggest an unconformity with the underlying strata. The sand here overlies red, highly ferruginous sand of Eocene age. The gray sands are also exposed on the Georgia side west of AuguE>ta, at Monte Sano, at which place also a few pebbles were noted. The sands also mantle the hills and ridges westward from Augusta. Notable thin coverings of grayish or brownish quartz sands, probably residual, occur in the vicinity of Grovetown, Columbia County, and are also well developed over the hill tops and slopes southward from this place to Hephzibah, Richmond County. They attain a thickne&'s of only a few feet. In this region the sands are underlain principally by Eocene strata.
At Keysville, in the northwestern corner of Burke County, the surficial sands reach a thickness of 10 to 18 feet and do not seem to be in any way connected with the drainage of the country. The
1Loughridge, R. H., Cotton Production: Tenth Census, Vol. 6, p. 38.

452

GEOLOGY OF THE COASTAL PLAIN

sands are in general yellow or brownish, and, when moist, resemble oak sawdust; but in places at the surface they have beern leached almo::.t pure white. They consist almost entirely of subangular quartz, but microscopic examination reveals a few. rounded grains of opalescent silica; limonite forms a coating over the quartz grains ; there is some organic matter at the surface to which the characteristic dull gray appearance is due. No trace of stratification appears in any of the exposures. About two miles east of the town there is in these sands a circular depression which probably resulted from the irregular heaping up of the sands by wind action. The surficial sands overlie red, argillaceous sands of Eocene age.
About 10 feet of brownish, incoherent sand overlies the Cretaceous strata in the railroad cut at Carrs Station, Hancock County, and similar sands appear at other localitie::. in the southern part of the same county.
In a cut of the Central of Georgia Railway, about three miles west of Griswo-ldville, Jones County, 10 to 15 feet of loose, surficial sand overlies red Eocene sand from which it does not seem to be sharply separated. Although so great a thickness of sands of the residual class is not common, the nearly pure character of the underlying Eocerne sands at this locality renders this explanation of the origin of the deposit the most probable one.
The gray, pebbly sands appear as a thin covering over the high level upland west of Macon, lying about 200 feet above Ocmulgee River. They appear to be residual from the underlying pebbly formation. The gray sands and gravels are mined at a small pit three miles west of Macon near the Columbus road.
The gray sands are well developed southeast of Roberta, Crawford C~unty. They do not appear at all on Rich Hill, which is capped by Eocene strata, and which is probably the highest point in the Coastal Plain; over the adjacent Lower Cretaceous area to the southward they form a thick mantle covering a belt a few miles wide. In this r:egion the sands are gray at the surface, and light yellow at depths, and are composed almost entirely of qua,rtz. The thickness averages four to six feet but locally reaches 10 to 15 feet. At many places in this region the surface is dotted with numerous small, oval hillocks of sand, 8 or 10 inches high, thrown up by a burrowing pouched gopher, locally known as a "salamander." This small rodent is common elsewhere in the sand hills of the Coastal Plain. To the southward of this region in the Fort Valley area the surficial sands appear to be entirely absent.
The best known development of the surficial sands occur on the high plain' stretching from three miles east of Butler, Taylor County,

SURFICIAL SAND

453

westward to Geneva, Talbot County, in the region traversed by the Central of Georgia Railway. This plain reaches an elevation of 650 feet or more above sea-level. The sands are being excavated for. commercial purposes at Howard and Junction City.
Near Butler the sands are only five or six Jeet thick. They extend northward from Butler to the border of the Piedmont area.
At Howard, near the pits of the J. M. Brown Sand Company, the sands attain a probable maximum thickness of over 30 feet. Thirty feet of sands appear in the pits near the railroad, one mile west of Howard. They are entirely unconsolidated and show but little evidence of stratification. At the surface they are gray or light buff in color but in places at depths are' slightly darker. These sands overlie Lower Cretaceous strata apparently filling old erosion hollows; although there are these local indications of unconformity it is believed that the sands are residual from the underlying Cretaceous strata, but in places have been shifted into ravines by winds and torrents.

Section in pit of J. M. Brown Sand Company at Howard.

1 Surficial sand. 5. A~s~!~ s~r~a~e-:-~n.e-~r~i~e~,. g.r~y. o~ ~~o~n.is~

4. Light yellow sand . . . . . . . . . . . . . .

25

3. Almost white sand, showing some evidence of

water stratification . . . . . . . . . . . . } 2. Ferruginous sand containing a very small per

centage of clay . . . . . . . . . . . . . . .

5

1. White sand . . . . . . . . . . . . . . . . . .

Microscopic examination of a sample of the surficial gray sand from this locality revealed chierfly subangular quartz grains with slight amounts of mica in fine flakes, some decomposed feldspar attaGhed to quartz grains, minute particles of black sand, and a small amount of iron oxide which forms a coating over the quartz grains; the clay content does not erxceed one or two per cent.
Near Junction City, Talbot County, the sands reach a thickness of 20 feet; in color they are light bluff or dull gray; as at Howard, they are composed, of subangular quartz with minor amounts of clay, iron oxide, mica, and black sand; they are genecr.-ally fine in texture . but a few rounded quartz pebbles about the size of buckshot were observed in places. The deposits are wholly unconsolidated and reveal no stratification.
Similar sands are present in the region to the southward of the above mentioned places and overlie the Upper Cretaceous and lower Eocene beds. Over a large part of the limestone region of southwestern Georgia they appear to be absent, the soils consisting of

I

454

GEOLOGY OF THE COASTAL PLAIN

red, argillaceous sands residual from the Eocene and Oligocene formations; they have been noted in a few places, however, as in . the region east of Americus, Sumter County; north of Shellman, Randolph County; over a large part of Lee County; in the we5tern part of Bakecr County; and in Miller County.
Large accumulations of sand appear in the form of dunes 30 or 40 feet high on the east side of Flint River at Albany; the maxim11m elevations of their summits above the river is about 100 feet. Among the dunes are undrained depressions probably due in part to the collapse of solution caverns in the underlying Vicksburg limestone, and in part to the irregular heaping up of the sand by wind. The sands are gray or light buff in color and are composed entirely of subangular quartz grains; in composition and appearance they resemble the gray sands of the Fall Line region. Small, angular and fiat flint chips are scattered through the sands; since these fragments show no evidence of having been water-worn in transportation they are believed to be the chippings left by Indians in the manufacture of arrows, hatchets; etc. Similar flint chips have been observed at Dublin in sand described on a following page. The sands were probably accumulated during the' early Pleistocene period.
"Wire-grass" sand hills.-Grayish and brownish sands are present as a surficial covering over nearly the whole of the "wire-grass" upland east of Flint River. Generally they form only a thin residuat covering over the mottled, argillaceous sands and clays of the Altamaha (Lafayette ?) formation. The thickness of the sand averages two to folir feet, but at a number of localities there are accumulations reaching 10 to 25 feet. A few of the more conspicuous localities are mentioned below:
In the southeastern part of Burke County, and also in Screven County, are heavy beds of surficial gray sand of probable residual origin lying between Briar Creek and Savannah River. The sands reach a thickness of from 3 to 10 feet and overlie, alike, the Barnwell sand of the Claiborne group and the Altamaha (Lafayette ?) .formation. They lie on the divide between the two streams at elevations of 125 to 150 feet above Savannah River.
On the east side of Oconee River, opposite Dublin in Laurens County, is a conspicuous accumulation of sand lying about 100 fee.t above the river and reaching a maximum thickness' of 20 feet. See plate XXX, opposite page 448. The sands are gray to light buff in color. Near the surface they are rather fine, incoherent, and structureless, but with depth become slightly coarser and near the base exhibit current bedding. Between this sand accumulation and the river there are gray -sands of terrace origin which are certainly of

SURFICIAL SAND

455

Pleistocene age and referable to the Okefenokee formation. Quartz pebbles were noted in the upland gray sands south .and southwest of Dublin.
A fine exposure of sand appears in a cut of the Seaboard Air Line Railway two miles east of Helena, Telfair County, on the east side of Little Ocmulgee River. The sand bed reaches a thickness of 25 feet; it is gray or light buff in color, becoming coarser and almost white at the bottom of the cut; very coarse sand and a few pebbles were noted near the contact with the underlying formation. The sand hill reaches a height of 75 feet above the river and extends southward to the junction with the Ocmulgee at Lumber City. On the west side of the river only a thin coating of the gray sand is
present.
The gray sands are well developed in the region traversed by Cannoochee River and its tributaries. A notab~e deposit occurs on the east side of Cannoochee River five miles northeast of Stillmore, Emanuel County, where it is well exposed in a cut of the Georgia and Florida Railway. The sands reach a thickne,ss of 15 feet; are gray, yellow, or light buff in color, and have the characteristics of similar accumulations at other localities. Wavy lines one-eighth of an inch thick or less, of ferruginous, darker colored sand, present the only ervidence of stratification. At one point in the cut a high percentage of iron oxide was observed, rendering the sands yellow or orange in color; a few thin, limonitic crusts were noted. This deposit is well above the river and is certainly not a Recent floodplain' accumulation. On the west side of the river there is only a very thin film of sand over the Altamaha (Ldayette ~) formation~
Similar deposits occur along the Georgia and Florida Railway on the north side of Ohoopee River, six miles southeast of Stillmore; on the north side of Pendletons Creek; and near Normantown.
Near Reidsville, on the east side of Ohoopee River in Tattnall County, is a heavy sand bed covering a belt two to three miles wide. The sands are white at the surface in places and in a photograph produce the effect of snow. The deposit lies well above the river and apparently is not of river terrace origin. However, gray sands, locally termed "sand hammocks" which are probably of Pleistocene tel'race origin, occur at lower levels along the river.
There is an extraordinary development of sand on the east and north side of Satilla River, and its tributary, Seventeen Mile Creek, extending from western Pierce County opposite Waycross, to Douglas, Coffee County. This deposit consists of gray, yellowish or b~ownish, incoherent quartz sands free from pebbles and clay, and for the most part structureless or showing only very faint structure.

456

GEOLOGY OF THE OOASTAL PLAIN

In places the sands reach a thickness of 20 or 30 feet or more. The altitude of the sand hills above Satilla River is about 50 feet, or about the same as the general upland level of the same region. The sands lie at a higher elevation than the sands of the Okefenokee terrace plain east of Waycross, and because of their higher elevation are supposed to be older than that formation. In places in this belt there are in the sands roughly circular, shallow depressions which during rainy seasons., hold water and form sand hill ponds. It is not known whether these sands are of beach and wind-dune origin along the shore of a Pleistocene estuary or whether they were deposited as alluvium. It is certain, however, that they owe their present form in part to wind action.
Considerable accumulations of surficial sand cover the high plateau on the east side of Flint River from near Faceville, Decatur County, southward to River Junction, Fla. The sands are buff or dirty gray in color, due to iron oxide and to a small amount of organic matter from growing 'vegetation. They are loose in texture and resemble the surficial sands of the Fall Line region and elsewhere. A sample from near the 255th mile-post on the Atlantic Coast Line Railway between Recovery and River Junction was examined microscopically. It was found to consist chiefly of fine, sub:angular quartz with a small percentage of well rounded, or spherical :grains, and a very small percentage of clay.

INDEX

Page.

A

Adrian, section near . . . . . . . . .

. . . . . . . . . . . . . . 414

Aeolian, sand deposits . . . . . . . . . . . . . . . 442, 443 448, 450, 452, 454

Agate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337, 344, 353

Albany, artesian well at . . . . . . . . . . . . . . . . . . . 200-201, 317-319

Sand hills near . . . . . . . . . . . . . . . . . . . . . . . . 450, 454

Vicksburg formation near . . .. . . . . . . .

. 316-319

Albion Kaolin Co. section at mines of . . . . . . . .

.

105

Aldrich, T. H., fossil determinations by . . . . . . . .. . . . . . . . . 420

Alexanders Landing, Chattahoochee R. section at . . . . . . . . . . . 178-179

Allapaha River, sections along . . . . . . . . . . . . . . . . 340, 353-354

Altamaha (Lafayette) formation . . . . . . . . . . . . . . . . . . . 400-423

Altamaha River, course of . . . . . . . . . . . . . . . . . . . . . .

41

Detailed sections along . . . . . . . . . . . . . 359-360, 376-377, 409-413

Altamaha Upland . . . . .

31-34

Alum Bluff formation . . . . . . . . . . . . . . . . . . . . . . . . 342-362

Alum Bluff, section at . . . . . . . . . . . . . . . . . . . . . . . . 342

Americus, geology near. . .

. . . 267, 314

Andersonville, geology near . . . . . . . . . . . . . . . . . . . 235, 267, 313

Anticlines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41, 63

Appalachian Mountains .

. . . . . . . . . .

26

Appalachian Valley . . . . .

. . . . . . . . . .

26

Appalachicola Group . . . . . . . . . . . . . . . . . . . . . . . . . 324-362

Arkose . . . . . . . . . . . . . . . . . . . . . . . 84, 104, 269, 403, 404, 417

Arlington, Vicksburg near . . . . . . . . . . . . . . . . . . . .

313

Atkinson, Wayne County, section at King plantation . . . . . . . . . 419-420

Attapulgus, fullers earth and sections near . . . . . . . . . . . . . . 349-350

Augusta, Cretaceous near . . . . . . . . . . . . . . . . . . . . . . 103, 105

Pleistocene at . .

. 433, 441

Surficial sand at . . . . . . . .

. . . . . . . . . . . . . . . 451

B

Bainbridge, geologic notes and sections near. . . . 320-322, 329-332, 347-348

'Barnwell sand .. . . . . . . . . . . . . . . . . . . . . . . . . . 285-29()

Barrows Mill, Houston County, section at. . . . . . . . . . . . . . . 197, 217

Basin, Claiborne, along Savannah River. . . . . . . . . . . . . . . 239

Bassler, R. S., fossil determinations by . . . . . . . . . . . . . . . . 260, 396

Bauxite . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72, 75, 96, 2~~

Bays, definition of . . . . . . . . .

.

.

.

3~

Beach pebbles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371, 435

Beach deposits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446

Beards Bluff, Pleistocene at. . . . . . . . . . . . . . . . . . . . . 44:\

Berry, E. W., on fossil plants in Georgia . 73, 87, 119, 123, 128, 144, 163, 171,

173, 209-210, 246

Bibb County, Lower Cretaceous in . . . . . . . . . . . .

90-91

Claiborne in . . . . . . . . . . . . . . . . . . . . . . . . 283, 295-29!i

Big Pond, Appling County . . . . . . . . . . . . . . . . . . . . . .

49

Blakely, log of well at . . . . . . . . . . . . . . . . . . . . . . . 201, 312

Blue Bluff, Savannah R. section at . . . . . . . . . .

. . . . 249-256

Blue Spring, Decatur County . . . . . . . . . . . . . . . . . . 325, 330, 331

Blue Spring Dougherty County . . . . . . . . . . . . . . . . . . . .

50

Blufftown, Chattahoochee River, section and fossils . . . . . . . . . 134-137

Boston, formations near . . . . . . . . . . . . . . . . . . . . . . . 338, 351

Boyd Farm, Burke County, fossil collection at . .

.

289

Broken Arrow Bend, section at . .

. . . . . . . . . . . . . . 117-119

457

458

INDEX

Brunswick, Miocene at . .

. . . . 377-378

Pleistocene at . . . .

436

Buena Vista, sections near

. 163, 196, 217

Log of well at . . . .

190

Buffalo Swamp . . . . . .

37, 49

Bugs Bluff, Altamaha River, section of .

412

Buhrstone formation . . . . . . . . . .

. 238, 262

Burke County, Claiborne in

. 242-251, 287-290

Surficial sand in . . . . . . . . . . . . . . . . . . . . . . . 451-452, 454

Burnt Fort, marl at . . . . . . . . . . . . . . . . . . . . . . . . . 380, 381

Pleistocene near .

439

Byron, sections near. . . . . . . .

. . . . .

. . . . . . . . 169-171

c

Calico Hill, St. Marys River . . . .

399

Camden County, Pleistocene in . . .

. 439-440

Cannoochee River; sand hills along .

455

Cape Fear beds . . . . . . . . . .

109

Carrs Station, geology near . . . .

. 79, 99, 452

Chalk Bluff, St. Marys River, section at

. 399-400

Chalker, Claiborne near . . .

276

Charlton formation. . . . . .

. 392-400

Chattahoochee formation . . .

. 324-342

Chattahoochee River, map of .

79

Pleistocene along . . . . . . . . . . . . . . . . . . . . . . . . 431, 444

Sections along . . . . . . 78-83, 117-123, 131-138, 172-181, 231-232, 262-264

Structure along . . . . . . . . . . . . . . . . . . . . . . . . . 63, 64

Chimney Bluff. section .

. 122-123

Fossils from . . . .

. 132

Claiborne group . . . . .

. 235-296

Historical summary.

. 235-237

Divisions of . . . .

236

Clark, W B. . . . . . .

. 111, 179, 341

Clay Landing, St. Marys River, section .

.

396

Clays, of commercial value . . . . . . .

. . 72, 75, 88, 231, 284, 346

Clays, silicification of . . . . . . . . . . . . . . . . . . . . . . . . 272, 344

Climax, Decatur County, sections near . . . . . . . . . . . . 348-349, 421-422

Section near, by J. W. Spencer. . . . . . . . . . . . . . . . . . 388-389

Coastal Plain, area of . . . . . . .

27

Elevations of above sea level .

27

Elevations, list of . . . . . . . .

50-57

Geology of, general statement .

58-G5

Physiography of . . . . . . .

27-50

Colerain bluff, St. Marys River . .

435

Collins, Altahama (Lafayette) at .

415

Colluvial sand deposits . .

450

Columbia formation . . . .

424

Columbia group. . . . . .

. . 425-445

Columbus, sections near.

. 78-86, 124-127

Wells near . . . . .

80-81

Pleistocene near . . .

. 382, 431, 444

Congaree clay member . .

. 2G7-284

Conrad, T. A., cited . . . . . . . . . . . . . . . . . . . . . . . 68, 236, 243

Copperas Bluff, section at . . . . .

. . . . .

226

Cordray Mill, geology near. . . .

. . . . . . . 266. 267, 299

Correlation, Cretaceous . . . . . .

. 108-111, 140-149, 204-215

Cowford, St. Marys R., section at .

397

Cox property, section on .

242

Cox spring, sections near . . . . .

. 287-288

INDEX

459

Crescent, Mcintosh County, Pleistocene at . . . . . . . . . . . . .

438

Cretaceous . . . . . .. . . . . . . . . . . . . . . . . . . . . . . 66-215

Historical review . . . . . . . . . . . . . . . . . . . . . .

. 67-73

Crystalline Area of Georgia . . . . . . . . . . . . . . . . . . . . . . 58

Crystalline floor, slope of . . . . . . . . . . . . . . . . . . . . . . . 62, 74

Cumberland Plateau . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Cusseta, Cretaceous near . . . . . . . . . . . . . . . . . . . 139-140, 162-163

Cusseta sand member . . . .

152

Cuthbert, geology near. . . . . . . .

. . . . . . . . . . . 234, 266, 311

D

Dall, W. H . . . . . . . . . . . . . . Danville Ferry, Flint River, section at . . Dawson, Vicksburg formation at ..... Demeries Ferry, Savannah R., section at. Diabase dike . . . . . . . Doctortown, section at . . . .
"Lafayette" at . . . . . . Dougherty Plain . . . . . . . Drainage of the Coastal Plain. Drainage in relation to structure . Drybranch, sections and geology near Dublin, Vicksburg near . . . .
Sand hill opposite . . . . . Dune sand and aeolian deposits Duplin Marl . . . . . . . . . . .

. 243, 247, 307, 342

260

312

248

28Q

. 377: 413

384

30-31

39-43

.

63

. 9294, 255-256, 294, 304

. . . . . . . . . 323

. . . . . . . . . 454

. 37, 389, 430, 432, 441, 454

. . . . . . . . . . 366-369

E

Ebenezer, Effingham County, Miocene at .

. . . . . . . . . . . . 375

Economic geology . . . . .

. 220, 283-284, 298-299, 311, 328, 346, 366, 369

Eden, sand hill near . . . .

443

Elevations in Coastal Plain

50-57

Ellaville, formations near .

. 191, 224, 235

Euchee Rapids, section at .

. 119-121

Eocene ........... .

. 216-306

Eufaula, Alabama, list of Cretaceous fossils from

. 176-177

Pleistocene at

43.1

Sections near . . . . . .

. 173-181

Eutaw formation . . . . . . .

. 111-149

Everhart, Edgar, analysis by .

446

Exogyra ponderosa zone

154

Exogyra costata zone . . . . .

154

F

Faceville, section at . . . . . . . .

. . . 333-334

Fall Line, definition of . . . . . . .

27

Fall Line Hills . . . . . . . . . .

28-30

Feldspar in Coastal Plain formations

. 403, 404, 405, 417

Flint of the Vicksburg formation

. . . 308-309

Flint River, course of

63

Pleistocene along . .

.. .

432

Sections along . . . .

. 225-226, 260-262, 314-322, 328, 332

Foerste, A. F. . . .. . . .

... .

. . . . .

34 7

Folkston, formations near

. . . . . . . . . 398-399, 426, 427

Forest Falls, sections at . . . .

. ..... .

.

. 334-336

Florence, section of Cretaceous at . . . . . . . . . . . . . . . . . . . 155-156

460

INDEX

G

Fort Gaines, log of well near . . .

. . . . . . . . . . . . . . . . 202

Pleistocei).e at . . . . . . . . . . . . . . . . . . . . . . . . . . . 431

Sections at . . . . . . . . . . . . . . . . . . . . . . 220-221, 231-233, 263

Fort James, Altamaha River, section at . . . . . . . . . . . . . . . 411

Fort Val~ey, notes on geology near .

. . . . . . 154, 168-169, 171, 386

Sectwn of well at . . . . . . . . . . . . . . . . . . . . .

171

Fossils, value of in stratigraphy . . . . . . . . . . . . . . . . . . . 61, 66

Fullers earth . . . . . . . 268, 269, 278-279, 283, 284, 343, 346, 349, 359, 409

Geologic formations, detailed description of

66-456

General statement about . .

. . . . . . .

58-65

"'Iap of . : . . . . . . . . . . .

. .

58

Tables of . . . . . . . . . . . . . . . . . . . .

. 48, 60-61

Thickness of_. . . . . . . . . . . . . . . . . . . . . . . . . . . 59-62

Georgetown, formations near . . . . . . . . . . . . . . . . 181-184, 222, 431

Georgia Kaolin Company, sections at mines of . .

. 93, 256, 304

Gibson, sections near . . . . . . . . . .

. 272-274

Gidley, J. W., fossil determinations by . . . . . . . . . . . . . . . 208-436

Gilmore, C. W., fossil determinations by . . . . . . . . . . . . . . . 175, 208

Girard, Vicksburg near . . . . . . . . . . . . . . . . . . . . . . . . 323

Glauconite beds . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

Glynn County, Pleistocene in . . . . . . . . . . . . . . . . . . . . . 439

Gosport greensand formation . . . . . . , . . . . . . . . . . . . . 236, 287

Gravel beds . . . . . . . . . . . . . . . . . . . . . . . . . . . 90, 431, 452

Grays Landing, Altamaha River, sections at . . . . . . . . . . . . . 409

Greens Cut, Burke County, formations at . . . . . . . . . . . . . . . 384

Greer Cave, Midway formation at . . . . . . . . . . . . . . . . . . . 223

Griffin Landing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250

Griswoldville, formations near . . . . . . . . . . . . . . . . . 94-95, 282, 452

Grit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403

Grovetown, section and geology near

. 102, 103, 269-271, 451

Gullies . .

29-30

Gypsum . . . . . . . . . . . . . .

. . . . . . . . 435

H

Hamburg beds, Cretaceous .

109

Hammocks .. . . . . . . .

. 34, 455

llancock Landing, section at

. 248-249

Harlem, sections at . . . . .

. . 271-272

Harper, R. M., quoted . . . . . . . . . . . . . . . . . . . . . . . 44-46, 391

Harris, G. D., cited . . . . .

. 270, 279, 282

Hawkinsville, section near . .

. 305, 322-323

Helena, sand hills east of . . . . . . . . . . . . . . . . . . . . . . . 455

Hephzibah, geology near . . . . . . . . . . . . . . . . . . . . . . 105, 290

Hershman .Lake . . . . . . . . . . . . . .

. 43, 324

Hicks Bluff, St. Marys River. section at . . . . . . . . . . . . . . . 394

House Creek bluff, section at . . . . . . . . . . . . . . . . . . . . . 357

Howard, Taylor County, surficial sand near .

453

Hudson's Landing, sections at . . . . . . . . . . . . . . . . . . . 361, 370

Ideal, section near . . . . . . . . . . . . . . . . . . . . . . . . . . 192

Igneous and crystalline rocks . . . . . . . . 73-74, 78, 84, 101, 104, 106, 280

Illustrations, list of . . . . . . . . . . . . . . . . . . . . . . . . 20-24

Iron ore . . . . . . . . . . . . . . . . . . . . . . . . . 164, 218, 220, 286

Irwinton, Lower Cretaceous near .

96

Islands, area and origin of . . . . . . . . . . . . . . . . . . . . .

37

INDEX

461

J

Jackson formation . . . . . . . . . . .

. . . . . . . . 296-306

Jacksonboro, Screven County, limestone near .

. . . . . . . . 341-342

Jamestown P. 0., section of Cretaceous at . . . . . . . . . . . . 138-139

Jefferson County, Claiborne in . . . . . . . . . . . . . 251-253, 272, 291-292

Jeffersonville, section near. . . . . . . . . . . . . . . . . . . . . . . 294-295

Johnsons Hill, Stewart County, section . . . . . . . . . . . . . . . 187

Johnsons Landing, formations at . . . . . . . . . . . . . . . . 306, 324

K

Kaolin . . . . . . . . . . . . . . .

. . . . . . . . . . . . 72, 75, 92-95

Keysville, surficial sand at . . . . . . . . . . . . . . . . . . . . . . 451-452

King Plantation, Satilla River, sections and fossils . . . . . . . . . 402, 419

Kittrells, section near . . . . . . . . . . . . . . .

.

305

Kramer, Wilcox County, Altamaha (Lafayette) at. . . . . . . . . . 417

L

Ladd, Geo. E., quoted . . . . . . . . . . . . . . . . . . 277-278, 389-390

Lafayette formation . . . . . . . . . : . . . . . . . . . . . . . 379, 380

Review of literature on . . . . . . . . . . . . . . . . . . . . 381-392

Relation to Altamaha formation . . . . . . . . . . . . . . . . . 392-407

Lakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41-43

Langdon, D. W., cited . . . . . . . . . . . . . . . . . . . . . . 70, 227, 262

Lignite . . . . . . . . . .

. . . . . . 116, 122, 270-271, 284

Lignitic group . . . . . .

. . . . . . . . . . . . . 227

Lime, rock suitable for . .

. 221, 250, 254, 299, 311, 314, 328

Limesink, Forest Falls . .

. . . . . . . . . 42

Sections at . . . . .

. . . . . . . . . . . . . 334-336

Limesinks . . . . . . . . . . . . . . . . . . . . . . . . 31, 33, 34, 42

Limestone, silicification of . . . . . . . . . . . . . . . 222, 292, 308, 313, 326

Linden Bluff, Attamaha River, section at . . . . . . . . . . . . . . . 412

Lithology, as a basis for mapping . . . . . . . . . . . . . . . . . . 61, 66

Little, Dr. George. quoted . . . . . . . . . . . . . . . . . . . . . . 69

Livingston plantation, section at . . . . . . . . . . . . . . . . . . . 378-379

Loughridge, Dr. R. H., cited . . . . . . . . . . . . . . . . . . . 49, 380, 451

Louisville oil well, log of . . . . . . . . . . . . . . . . 76, 100, 107-108, 252

Lower Cretaceous . . . . . . . . . . . . . . . . . . . . . . . . . . 73, 111

Lumber City, Pleistocene at . . . . . . . . . . . . . . . . . . . . . 433

Section of Alum Bluff formation at . . . . . . . . . . . . . . . 357

Lumpkin, sections near . . . . . . . . . . . . . . . . . 187, 194-195, 216-217

Lyell, Sir Charles, cited . . . . . . . . . . . . . . . . . 67, 243, :t41, 436-437

L7ell gullies . . . . . . . . . . . . . . . . . . . . . . 30

Me

McBean, fossils near . . . . . . . . . .

. 239-240

Sections near . . . . . . . . . . . .

. 242-243

McBean formation . . . . . . . . . . . .

. 237-284

McBride Ford, section of Cretaceous at . . . . . . . . . . . . . 86

McCallie, S. W., sections and notes by . . . . . . . . 71, 253-254, 283, 295, 305

Quoted on Lafayette . . . . . . . . . . . . . . . . . . . . . . . 391-392

McDuftl.e County, Lower Cretaceous in. . . . . . . . . . . . . . . . 101

McGee, W. J., cited on Pleistocene . . . . . . . . . . . . . . . . . . 424

Quoted on Lafayette . . . . . . . . . . . . . . . . . . . . . . 381-385

Mcintyre plantation, rocks at . . . . . . . . . . . . . . . . . . . . 337

462

INDEX

M

Macon, formations near . . . . . .

. . . . . . . 90-91, 283, 383, 390, 432

: Terracing at . . . . . . . . . . . . . . . . . . . . . . . . . . 383, 432

Mammalian remains . . . . . . . .

. 394, 435, 437

Map, geologic, opposite . . . . . . .

58

Marll:s Head, section at . . . . . . .

371

Marks Head marl . . . . . . . .

. . . . 363-366

Marl, description of at Shell Bluff . . . . . . . . . . . . . .

247

Marls and limestone for fertilizer . . . . . . ~ . . 220, 231, 247, 284, 328, 366

Mars~ and tide swamp . . . . . . . . . . . . . . . . . . . . . .

' 38

Area of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446

Marshallville, log of weir' at . . . . . . . . . . . . . . . . . . . . . 197

Matson, G. C., and Clapp, F. G., cited . . . . . . . . . . . . . . . . 306, 393

Midville, formations near . . . . . . . . . . . . . . . . . . . . . . 289, 416

Midway formation . . . . . . . . . . . . . . . . . . . . . . . . . 216-226

Millen, formations near . . . . . . . . . . . . . . . . . . . . . . . 341, 433

Miocene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362-379

Montezuma, sections near : . . . . . . . . . . . . . . . . . . . . . 224-225

Well at . . . . . . . . . . . . . . . . . . . . . .

. .

. . 202-203

Morris Landing, Chattahoochee River, Eocene at . . . . . . . . . . . 181, 220

N

Names of formations . . . . . . . .

. . . . .

.

61

Narrows, Pataula Creek, section and fossils . . . .

. 184-185

Nettles Landing, St. Marys River section . . . . .

. 296-397

New Savannah bluff, Savannah River section at.

442

Norwood, Lower Cretaceous at . . . .

. . . . . . . . .. . . . . .

101

0

Oakfield, Vicksburg formation near .

. . . . . . . . . . . . . . . 314-315

Ocean Pond, Lowndes County . . .

. . . . . . . . . . . . . . . 34-35

Ochille, section at . . . . . . . . . . . . . . . . . . . . . . . . . .

128

Ocmulgee River, sections along . . . . . . . . .

. . . . 305, 356-358

Pleistocene along . . . . . . . . . . . . . . . . . . . . . . . . 432, 443

Oconee River, sections along . . . . . . . . . . . . . . . . . . . 305-, 358-359

Ogeechee River, Alum Bluff formation along .

. . . . . . 360

Oglethorpe Bluff, Altamaha River, section at .

. . . . . . 411-412

Okefenokee Plain .., . .

. 35-36, 46, 425, 426

Okefenokee Swamp . . . . . . .

44-49

Map of, opposite . . . . . .

44

Okefenokee formation . . . . .

. 425-434

Old Town, list of fossils from .

. 292

Oligocene . . . . . . . . . . .

. 306-362

Adoption of the term . . . .,. .

. 307, 362

Olympia, section near . . . . . . . . . . . . . . . .

.

. . 339

Omusee Creek, Alabama, Claiborne at . . . . . . . . . . . . . . . . 263-264

Orange Bluff, St. Marys River, section at . . . . . . . . . . . . . . . 400

Pleistocene at . . . . . . .

440

Orbitoidal limestone . . . . . . . . . . . . . . . . . . . . . . . . . 310

Original Pond, formations at . . . . . . . . . . . . . . . . . . . . 336-337

Ostracods . . . . . . . . . . . . .

. . . . . . . . . . . . . . . 396, 399

Ostrea georgiana bed . . . . . . . . . . . . . . . . . . . . . . . . . 240, 244

Ostrea georgiana, description of . . . . . . . . . . . . . . . . . 243, 247, 250

Owens Ferry, Miocene at . . . . . . . . . . . . . . . . . . . . . . 379

INDEX

463

p

Paleozoic area of Georgia . . . . . .

. . . . .

58

Parramore Hill, Altamaha (Lafayette), at .

. . . . . 416

Pataula Creek, fossils and sections . . . . .

. 1'79-180, 184-186

Peat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

"Pebble" land . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405, 421

Penny Bluff, Flint River, section at . . . . . . . . . . . . . . . . . . 261

Perry, Cretaceous near . . . . . . . . . . . . . . . . . . . . . . . . 198-199

Sections south of . . . . . . . . . . . . . . . . . . . 258-260, 301-303

Phosphate . . . . . . . . . . . . . . . 326, 337, 338, 340, 344, 346, 354, 355, 363

Physiography . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-50

Piedmont Plain . . . . . . . . . . . . . . . . . . . . . o . . . . . 26-27, 58

Pikes Peak station, sections at . . . . . . . . . o . . . . . . . . . 278-279

Plant remains (see also Berry, E. W.) . . . . . 99, 269, 270, 271, 290, 370, 372 0
Pleistocene . . . . . . . . . . . . . . . . . . . . . . . 0 424-445

Pliocene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379-423

Ponds . . . . . . . 33, 34, 41-43 0

















0



Porters Landing, Savannah River, sections at . . . . . . . . . . . . 371-373

Fossil collections at . . . . . . . . . . . . . . . . . . . . . . . . 365, 368

Potholes . . . . . 0















0

















0





o . . . . . . 221, 233

Potomac formation . . . . . . . . . . . . o . . . . o . . . . . . . 70, 71

Powell Umesink . . . . . . . . . . . . .

. 332-333

Preston, Midway near . . . . . . . . : .

0

223

rrov1aence gullies . . . . . . . . .

. 30, 19"

Providence, Lumpkin County, section at.

. 19!

Providence sand member . . .

. 152-153

Sections of . . . . . . . . . . . . 0

0 192-198

Pumpelly, Raphael, cited . . . . . . . .

. 325

Purisburg, S. C., section at . . . . . . .

. 375-376

Pyles Marsh, reference to plate illustrating .

37

Q

Quaternary . . . . . . . . . . . . . . . . . . . . . 424-445

Quitman, geology near . . . . . . . . . . . . . . . . . . . . o . . 339; 352

Quitman County, Cretaceous in . . . . . . . . . . . . . . 181-183, 192-193

Eocene exposures in

. 222-223

Pleistocene in . . . . . . . .

. . . . . . . . . . . . . . . 431

R

Racepasses, Chattahoochee River, section at .

123

Rand Landing, St. Marys River, section .

0 395-396

Recent deposits . . . . . .

. 445-447

Red h1lls . . . . . . . . . . . .

29

Reidsv1lle, sand hill near . . . . . . .

455

Renfroe& marl formation . . . . . . . . . . . . . . . . . . . . 72

Rept1Uan remains . . . . . . . . . . . . . . . . . . . . . . 151, 208, 215

Reynolds, well at . . . . . . . . . . . . . . . . . . . . . . . . . 76

Rich Hill, Crawford County, formations at . . . . . . . 30, 88-89, 299-300, 385

Richland, Midway near . . . . . . . . . . . . . . . . . . . 223

Richmond Coo,mty, geology of . . . . . . . . . . . . . 103-105, 251, 290-291

Ripley formation . . . . . . . . . . . . . . . . .

. 149-215

Rivers of the Coastal Plain . . . . . . . . . . . .

40-41

Road metal . . . . . . . . . . . . . . . . . .

311

Rock House, Crisp County, section at. . . . . . . . . .

0

340

Roods Bend, Chattahoochee River, section and fossils .

. 159-160

Roberts Station, section and fossils . . . . . . . .

. 279-282

464

INDEX

Rose B,luff, Fla., fossils and section . . . . . . . . . .

. . 436 440

, Rors Hill, section of Jackson formation at. . . . . . . . . . . . . . ' 301

Rotten limestone formation . . . . . . . . . . . . . . . . . . . . . 69, 71

Rutland, Bibb County, section near

. . . . . . . . . . . . . . .

90

s

Sal.amander, in sand hills . . . . .

. . . . . . . . . . .

452

Sandersville, sections near . . . . .

. . . . . . . . . . .

253

Sand hills . . . . . . . . . . . . . . . . . . . . . . . . 29, 33, 77, 449-451

Origin of . . . . , . . . . . . . . . . . . . . . . . . . . . . . . 34, 77

Sand hill ponds . . . . . . . . . . . . . . . . . . . . . . . . . . .

34

Sand pits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

453

Sand streams . . . . . . . . . . . . . . . . . . . . . . . . . . . 30, 164, 447

Sandersville, geologic formations ne~r . . . . . . . . . . . . . . 253, 274-275

Log of well at . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Sansavilla bluffs, Altamaha River, sections . . . . . . . . . . . . . . 413

Satilla Coastal Lowland . . . . . . . . . .

. 36-39 434

Satilla formation . . . . . . . . . . . . . . . . . . . . . . . . . . 434-445

Satilla River, course of . . . . . . . . . . . . . . . . . . . . . . . .

41

Formations along . . . . . . . . . . . . . . . . . . . . . . . . 379, 392

Sand hills along . . . . . . . . . . . . . . . . . . . . . . . . 455-456

Savannah, Altamaha (Lafayette) near . . . . . . . . . . . . . . . . 417

Pleistocene near . . . . . . . . . . . . . . . . . . . . . . . . . 437-438

Savannah River, sections along . . . . . . . 105-106, 243-251, 361-362, 370-376

Pleistocene along . . . . . . . . . . . . . . . . . . . . . . 433, 441-442

Savannas . . . . . . . . . . .

37

Sawpit Landing, section at . .

398

Second bottoms . . . . . . . . .

39

Sellards, E. H., cited . . . . . . . .

440

Selma Chalk . . . . . . . . . . . .

. 69-71

Shell Bluff, description of strata at . . .

. 243-247

Silver Bluff, Savannah River, Pleistocene . .

. 442

Sister Bluff, Altamaha River, section of . .

. 410-411

Sisters Ferry, Savannah River, section at . . . . . . . . . . . . . 374-375

Slick Bluff, Chattahoochee River . . . . . . . . . . . . . . . . . . 71, 120

Sloan, Earle, cited and quoted . . . . . . . . . . . . . . . 236, 239, 267, 371

Smith, E. A., cited . . . . . . . . . . . . . . . . . . . . . . . . 69, 112, 177

Smithville, Claiborne near . . . . . . . . . . . . . . . . . . . . 267

Soils . . . . . . . 29, 32, 35, 238, 269, 287, 309, 345, 351, 364, 367, 405, 430,

.

447, 453-454

Southern Limesink region . . . . . . . . . . . . . . . . . . . . . 34-35

Spencer, J. W., on Cretaceous geology . . . . . . . . . . . . . . . .

71

Quoted . . . . . . . . . . . . . . . . . . . . . . . . . 261-262, 385-389

Section by . . . . . . . . . . . . . . . . . . . .

387

Springs . . . . . . . . .

49-50

Stanton, T. W. . . . . . .

.

23

Fossil collections by .

. 178-180

St. Marys River, course of

. . . . . . . . . . . . . . . . . .

41

Detailed sections along . . . . . . . . . . . . . . . . . . . . 356, 393-400

St. Stephens limestone formation .

306

Stephenson, L. W. . . . . . . . . . . . . .

22-23

Stevens Pottery, sections at . . . . . . . .

.

97

Stewarts Hill, Chattahoochee River, section
Section of by J. w. Spencer .

. 174-175 387

Stillmore, sand hills near .

. 455

Stokes Ferry, section . . . . . .

. 393-394

Stony Bluff, section at . . . . . .

290

Stony Lake, section at . . . . . . . . . . . . . . . . . . . . . . . . 339

INDEX

465

Structure of the Coastal Plain . . . . . . . . . . . . . . . . . . 62-65 During deposition of Claiborne . . . . . . . . . . . . . . . . . . 239
Submergence, coastal . . . . . . . . . . . . . . . . . . . . . . . . . 37, 38 Surficial sands . . . . . . . . . . . . . . . . . . . . . . . . . 402, 447-456 Suwanee River, formations along . . . . . . . . . . . . . . . . . . 355, 445 Swamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43-49 Sylvester, Chattahoochee formation near . . . . . . . . . . . . . . . 327

T

Talbot County, Lower Cretaceous in

.

87

Taylor County, Lower Cretaceous in . . . .

87-88

Tennille, Sections near . . . . . . . . . .

254

Log of well at . . . . . . . . . . . . . . . . . . . . . . . . . 107

Terraces . . . . . . . . . . . . . . . . . . . . . . . . . . 35-38, 39, 424, 441

Elevations of . . . . . . . . . . . . . . . . . . . . . . 424, 425, 430, 441

Terrace deposits, described in sections (see under Pleistocene) . . . . 424-445

(See also various sections along Chattahoochee, Flint, Ocmulgee,

Altamaha and S'avannah Rivers).

Tertiary . . . . . . . . . . . . . . . . . .

. 216-424

Thickness of . . . . . . . . . . . . .

61

Thickness of Coastal Plain strata . . . . .

61-62

Thomas Bluff, Chattahoochee R., section at .

82

Tide Swamp . . . . . . .

38

Tivola, section at . . . . .

303

Tombigbee sand member .

. 112

Correlation of . . . .

. 145-149

Sections of . . . . . . . . . . . .

. . . . . . . . . 131-138

Turtles, fossil . . . . . . . . . . . . . .

. . . . . . . . . . . 151, 219

Tuscaloosa formation . . . . . . . . . . . . . . . . . . . . . . 70, 109, 112

Twiggs County, Claiborne formation in . . . . . . . 255-257, 278-279, 293-295

Jackson formation . . . . . .

304

Lower Cretaceous in . . . . .

. . . . . . . . . . . . . . . 91-94

u

Underwood Ferry, formation near . . . . . . . . . . . . . . . . 165, 217

Upatoi Creek, sections along . . . . . . . . . . . . . . .

. 126-127

Upper Cretaceous . . . . . . . . . . . . . . . . . . . . .

. 111-215

Unio, in Lower Cretaceous . . . . . . . . . . . . . . . .

77

United States Geological Survey, co-operative work with .

22

v

Vaughan T. Wayland, supervisory and paleontologic work. . . . . .

22

Notes and sections by . . . . . . . 242-243, 258, 259-260, 261, 273, 281-282,

315, 321-322, 328, 333, 393

Veatch, Otto, work of .

. . . . .

. . . . . . . 22-23

Vicksburg formation . . . . . . . . .

. . . . . . . . . . . . . . . 306-324

w

Washington County, Claiborne in . . . . . . . . . . . . . 253-255, 274-276

Waycross, Altamaha (Lafayette), near . . . . . . . . . . . . . . . 418-419

Waynesboro, formations near . . . . . . . . . . . . . . . . . . 288-289, 415

Westlake, Jackson formation near

304

Weston, section near .

. . . . . . . . . . . . . . . . . . . . 235

Wilcox formation . . . . . . . . . . . . . . . . . . . . . . . . . . 226-235

466

INDEX

Wilkinson County, geologic formations of .

. 95-97, 276-278, 293

Winokur, Charlton County, marl near .

392

Wiregrass . . . . . . . . . . . . . . .

32

Wiregrass region . . . . . . . . . . . .

. 449

Wiregrass sand hills . . . . . . . . . . . . . . . .

. 454-456

Woolridge Landing, Chattahoochee River, sections .

. 157-158

Wylie Landing, Decatur County, section at . . . . . . . . . . .

334

X YZ

Zenith, sections near . . . . . .

. . . . . . . . . . . . . 167

Zeuglodon . . . . . . . . . . . . . . . . . . . : . . . . . . . . . ~ 298, 300