Lih:-~ry Dept. of N~~:m~l ~~~;j~r~es Ear~h and Wat~r iiivlsiuo. C , 2.. Project Report No. 4 South Georgia Minerals Program Georgia State Division Of Conservation Department of Mines, Mining and Geology A. S. Forcron, Director PHOSPHORITE EXPLORATION - IN PORTIONS OF LOWNDES, ECHOLS, CLINCH AND .II~III-. CHARLTON COUNTIES, GEORGIA By Norman K. Olson Industrial Development Department -. Southern Railway System . October 1966 ! II Prepared through the cooperation of Southern Railway System, Washington, D.C. PROJECT REPORT NO. 4 SOUTH GEORGIA MINERALS PROGRAM GEORGIA State Division of Conservation Department of Mines, Mining, and Geology A. S. Furcron, Director By Norman K. Olson General Industrial Geologist Industrial Development Department Southern Railway System October 1966 Prepared through the cooperation of Southern Railway System, Washington, D.C. CONTENTS ABSTRACT . INTRODUCTION ACKNOWLEIDGMENTS PURPOSE AND SCOPE OF INVESTIGATION . DEFINITIONS FIELD AND LABORATORY PROCEDURES Drilling, coring and sampling Electric and gamma-ray logs Altitudes Chemical analyses GENERAL GEOLOGY . STRATIGRAPHY General statement Lower Miocene . . Middle Miocene (?) "Hawthorn 11 Formation Age Lithology Distribution Upper Miocene Post-Miocene STRUCTURE General statement Withlacoochee Anticline Southeast Georgia Embayment Minor fold . . . . . . . . Relations to Ocala uplift ii Page iv l 3 5 6 8 8 8 9 9 16 19 19 21 26 27 27 29 31 31 32 32 33 35 35 36 iii CONTENTS (Continued) Page GEOMORPHOLOGY . . . . . . . . 38 General statement 38 Relations of karst topography to phosphorite occurrence 38 Subsurface cavities and unusual phosphorite thicknesses 39 Stream patterns 39 other investigations 41 Influence of Trail Ridge 42 PHOSPHORITE 43 General statement 43 Western portion 44 Eastern portion 47 Relationships among color, grade and mineralogy 49 SUMMARY AND CONCLUSIONS 53 Future prospecting . REFERENCES CITED BASIC DATA 1. Summary of drilling and analytical data 55 . . . . . .. 57 60 61 2. Driller's logs .. 87 iv TABLES 1. Provisional certificate of analysis -- National Bureau of Standards 2. Chemical analyses of washed, plus-200-mesh samples 3. wCaosmhpeadripsohnosopfhopreirtecensatmPp2loe5s content in unwashed samples and retained on a 200-mesh sieve 4. Comparison of core and cuttings analyses 5. Summary of mapped formations in project area 6. Summary of Tertiary subsurface data in Georgia from other reports . . . . . . . . . . . . . . . . . . . . . 7. Solution cavities and probable cavity fillings encountered in drill holes . . . 8. P2o5-u relationships to color of phosphate pebbles Page 10 l2 13 15 20 22 40 51 v ILLUSTRATIONS Plates (All plates in pocket) I. Phosphate drill hole locations in Lowndes, Echols, Clinch and Charlton Counties, Georgia II. Cross-sections showing distribution and grade of phosphorite in the eastern Lowndes-western Echols county area (Sections A-A' through C-C') III. Thickness distribution of phosphorite overburden IV. Thickness distribution of phosphorite V. Major structural and geomorphic elements in a portion of the Georgia-Florida area Figures 1. South Georgia and North Florida showing area of investigation . . . . . . . . 2. Diagrammatic Section D-D' showing relationships of phosphorite and associated lithology between western and eastern portions of project area . . . . . . . Page 17 30 vi ABSTRACT During Spring 1965 Southern Railway and the Georgia Department of Mines, Mining and Geology undertook a joint phosphorite exploration program. Known occurrences in North Florida guided the investigation into extreme South Georgia -- Lowndes, Echols, Clinch and Charlton Counties. OVer 3000 samples were collected from more than 160 drill holes. Prepared sample cuts for microscopic description are deposited with the State of Georgia for public use. Phosphorite of low commercial grade, that is, 9 percent P2o5 or higher, occurs almost entirely in the western portion of the study area. It is found in transparent quartz sands. These zones commonly have 25 to 35 feet of overburden, and the phosphorite thickness generally ranges from 20 to 40 feet. Structural control has influenced the accumulation of phosphorite in the four-county area in a broad sense. The two major structural features are the Withlacoochee Anticline to the west, and the Southeast Georgia Embayment to the northeast. Localization of much phosphorite in the western portion, however, is apparently in sinkholes and solution channels produced in the underlying Suwannee Limestone of Oligocene age. Drilling and chemical results are given in various tables, driller's logs, geologic cross-sections, and thickness distribution maps. PHOSPHORITE EXPLORATION IN PORTIONS OF LOWNDES, ECHOLS, CLINCH AND CHARLTON COUNTIES, GEORGIA INTRODUCTION A sharp increase in world-wide demand for phosphate compounds, par- ticularly agricultural fertilizers (Piombino, 1964), has stimulated new interest for geological exploration by many chemical, petroleum and mining firms. Increasing attention to the mining potential of phosphate rock in the South Georgia-North Florida area provided the impetus for this investigation. Occidental Corporation of Florida, a subsidiary of Occidental Petroleum Corporation, was the first company in the general area to initiate construetion of a washer plant to produce phosphate concentrate. That plant was begun near Purvis Still in Hamilton County, Florida, in October, 1964, followed by construction of additional units of an agricultural chemicals complex in late Summer 1965. Companies interested in the Georgia portion of the phosphate rock area began expressing their interest to the Department of Mines, Mining and Geology, State of Georgia, and to the Industrial Development Department of the Southern Railway System, as well as other agencies offering geological services. In Spring 1965, the Industrial Development Department of the Southern Railway, through the cooperation of the Department of Mines, Mining and Geology, began a reconnaissance drilling program for phosphorite in parts of Lowndes, Echols, Clinch and Charlton Counties, Georgia. Holes were drilled at one-mile intervals on railroad and county road rights-of-way and on private land. Continuation, Introduction 2 All drilling and chemical results have been furnished to the State of Georgia, and the samples, prepared for microscopic study, remain with the State for public use. 3 ACKNOWLEDGMENTS The writer expresses thanks to Dr. A. S. Furcron, Director of the Department of Mines, Mining and Geology, State of Georgia. He provided the outlet for publication of the report. Preparation of cuttings samples for microscope description, and their storage, was made possible through the joint cooperation of Dr. Furcron and John E. Husted and the staff of the Mineral Engineering Branch, Georgia Institute of Technology. Thanks are due to J. Roger Landrum, Chemist, Department of Mines, for performing the more detailed chemical analyses. The writer is particularly grateful to the following U. S. Geological Survey personnel: Dr. S. M. Herrick assisted with determining the series boundaries on the drill holes shown in the cross-sections (Plate II). His long experience in subsurface work proved invaluable in this respect. James B. Cathcart, Denver, and Robert C. Vorhis, Atlanta, reviewed the manuscript. Mr. Cathcart spent two days on drilling location with the writer and furnished assistance based upon wide experience in the phosphate minerals. He also provided X-ray diffraction data on the clay minerals. Charles W. Sever, geophysicist, formerly with the U. S. Geological Survey, Tifton, Georgia, furnished valuable field assistance and provided helpful comments on the general subsurface geology of the area. Dr. H. K. Brooks, Department of Geology, University of Florida, pro- vided beneficial comments. His studies in the areas bordering the Alapaha and Suwannee Rivers indicate late Miocene and Pliocene ages for some of the phosphorite. Gail F. Moulton, Jr., project geologist for the Kerr-McGee Corporation, Gainesville, Florida, furnished information on the Pliocene horse tooth locality near Lake City, Florida. Continuation, Acknowledgments 4 Thanks are also due R. Fred Phillips of Southern Railway for typing the rough draft and Mrs. Joyce E. Fowler of Georgia Institute of Technology for typing the final manuscript, and Jack Bradley and John Hines of the Georgia State Highway Department for drafting the maps and cross-sections. FMC Corporation, Pocatello, Idaho, kindly furnished comparative chemical results on drilling versus coring. Many local citizens over the four-county area were most helpful. Of special note was the assistance given by E. K. Avriett, Jr., pharmacist, Homerville, Georgia. 5 PURPOSE AND SCOPE OF INVESTIGATION The main objective in this study was to obtain generalized facts on the occurrence and distribution of phosphorite in the four-county area. The reconnaissance program was initiated with the idea of assisting those companies interested in phosphate exploration in the Georgia-Florida area. The investigation was conducted to get preliminary data. No attempt was made to gather metallurgical laboratory analyses because only a limited amount of coring was done. Therefore, no tonnage estimate of recoverable concentrate are given. What is intended, however, is to give the reader an over-all conception of the distribution of phosphorite and its relations to the stratigraphy, structure, and geomorphology of the area. 6 DEFINITIONS Some terms used in this report are of standard geologic usage, and others are identified with the phosphate industry. Definitions are taken from Altschuler and others (1964), and Howell (1960). Apatite: Attapulgite: The principal mineral of phosphorites is a carbonatecontaining variety of fluorapatite, called collophane or francolite, composed mainly of tri-calcium phosphate, Ca3(Po4 )2 A group of clay minerals, hydrous magnesium aluminum silicates, characterized by a distinctive rod-like shape. Synonymous with palygorskite. BPL: Bone P205 phosphate X 2.185. of lime (ca3(Po4 )2 ). Equals percent Clastic: A textural term applied to rocks derived from preexisting rocks. The commonest clastics are sandstones and shales. Concentrate: Fine phosphate product, -1 mm + 0.1 mm in size. Separated from quartz by flotation. Coquina: Soft porous limestone composed of broken shells, corals and other organic debris. Core hole: Boring by diamond drill or other machine that is made fGr the purpose of obtaining a core sample, that is, a section of the rock penetrated. Drill hole: Hole sunk by means of drilling tools. In this investigation toothed rock bits were employed producing cuttings and clay aggregates which were pumped to the surface. Isopach: A line on a map drawn through points of equal thickness of a designated unit. Kaolinite: Karst topography: A common clay mineral. Two-layer hydrous aluminum sili- cate having the general formula Al2 (Si2 o5)(oH4 ). A limestone plateau marked by sinks interspersed with abrupt ridges and irregular protuberant rocksj usually underlain by caverns and underground streams. Lithofacies: The rock record of any sedimentary environment, including both physical and organic characters. Continuation, Definitions 7 Lithology: Marl: Matrix: Montmorillonite: OVerburden: Pebble: Pellet: Phosphorite: Slime: Strand line: Strath: The physical character of a rock, generally as determined megascopically or with the aid of a low-power magnifier. A calcareous clay or intimate mixture of clay and particles or calcite or dolomite, usually fragments of shells. That part of the calcium phosphate zone from which phosphate particles can be economically recovered. Equal to 11 ore. 11 A group of clay minerals, hydrous aluminum silicates, characterized by swelling in water due to introduction of inter-layer water in the direction of the C-axis. Ca and Na cations subject to ion exchange. All rock overlying the matrix. Phosphorus pentoxide. Chemist 1s expressions for percent phosphate content. Coarse phosphate product, +1 mm in size. General term for rounded, oviform sedimentary apatite particles, commonly sand to granule in size. Rock name, called phosphate rock in the land-pebble district. Used in this report to denote a rock or specimen containing substantial amounts of sedimentary apatite. -0.1 mm material. Includes clay minerals, quartz, and phosphate minerals (apatite, crandallite, and wavellite). The line or level at which a body of standing water, e.g. the sea, meets the land. Valley deeply filled with alluvial deposits, particularly glacial outwash, not now occupied by a stream. 8 FIELD AND LABORATORY PROCEDURES Drilling, coring and sampling All drilling and coring were done by Tyson and Dean Water Well Company of Moultrie, Georgia~ Samples of cuttings were taken at five-foot intervals under the direction of the driller, L. L. Dean, by stopping drilling and pumping out all of the cuttings for the inte1~al. Because of the reconnaissance nature of the drilling, only 26 cores were taken. A total of 161 holes were drilled in Lowndes, Echols, Clinch, Charlton, and Lanier Counties (Plate I). Holes were drilled to 90 feet where phosphate was pres- ent, but were stopped at 75 feet where barren. Thirteen holes, spaced about 5 miles apart, were drilled for structural and stratigraphic reasons to depths of as much as 300 feet (Plate I). Drilling and sample data for all holes are summarized in Basic Data 1. Recent geologic field investigations in South Georgia by the Mineral Engineering Branch, Georgia Institute of Technology, have developed all basic data from core holes. By contrast this reconnaissance study employed very little coring, and nearly all samples are drill cuttings rather than an in situ section of the formation. Core holes and drill holes can be compared as to terminology under Definitions. It is readily apparent that some clay minerals are not recovered in the drilling process because of the drilling fluid used. Advantages and disadvantages of both methods are discussed under Future Prospecting, located in the final section. Electric and gamma -ray logs Electric logs were obtained to supplement the sample log information (Plate IV). Gamma-ray logs were run to detect the phosphorite zones. The phosphate particles themselves contain a small amount of uranium and their Continuation, Field and Laboratory Procedures 9 radioactivity can be detected by the gamma-ray instrument. A WIDCO portable model Y/PRG combination electric and gamma-ray logging instrument was mounted on the back of a pickup truck and operated from the vehicle's 12-volt battery. A probe at the end of a thin steel cable was carefully lowered by use of a hand crank into the completed hole. Pens on the chart paper were carefully "zeroed out" and set at the total depth. In the case of the electric logs, spontaneous potential was recorded on the left channel and resistivity on the right, both simultaneously. Electric and gamma-ray probes were interchangeable, and gamma-ray readings were recorded on the left channel only. Operational difficulties with the gamma-ray probe itself caused less than half the holes to have gamma-ray logs. Therefore, one aid to determining the position and thickness of the phosphorite was greatly reduced, Altitudes Very few topographic quadrangle maps are available for the four-county area. Therefore, it was essential to establish vertical control for the drawing of any cross-sections. Altitudes above mean sea level of selected drill holes were determined to the nearest foot, using a Zeiss surveyor's level. Level circuits were run from and closed on established U. S. Coast and Geodetic Survey bench marks. Surveys were performed by Thomas M. Lowe and Associates, Atlanta. Chemical ana1yses A National Bureau of Standards chemical analysis (Table l) is included to provide the reader with basic information as to the composition of Standard Sample l20a. Continuation, Field and Laboratory Procedures 10 Table 1. Provisional certificate of analysis by U. S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS (JuJ.s" 1961) Standard Sample l20a Phosphate rock (Florida) Percent P205 --- -- - - -------- -- ----- - -- - ------ Fe2o3------------ - ---- -------------- A~03 - - -- -- --------- -- - - ---- - - -- - - - Ca0--------------------------------- MgO--------------------------------F----------------------------------Mn0--------------------------------- Na20-------------------------------- K20--------------------------------- Ti02-------------------------------- C02------------------- - ----------- -- 34.4 1.00 .94 50.3 .26 3.92 .02 .41 .10 .12 3.18 Values are based on a sample dried for two hours at 110 C. A value for silica is not included at present due to poor agreement by different methods and analysts.* *Si02-----3.60% Determination by J. R. Landrum, Chemist, Georgia Department of Mines, Mining and Geology. Continuation, Field and Laboratory Procedures ll In the Basic Data 1, P2o5 determinations for selected drill holes are listed. Southern Testing and Research Laboratories, Wilson, North Carolina, performed the analyses. Approximately one pound of raw sample was sub- mitted for P2o5 analysis only. The sample as received was split, oven- dried, and treated with nitric-hydrochloric acid mixture. No washing was performed, other than that originally received by the sample in the slurry as it came from the subsurface. Considering present plant techniques, the writer arbitrarily selected all zones in holes having 9 percent P2o5 (19.7 percent BPL) or greater, as having commercial possibilities. Percent BPL, or bone phosphate of lime, is used as a standard in the fertilizer industry, and is equal to percent P2o5 X 2.185. In addition to the P2o5 determinations, four holes -- E45, E46, E54 and E69 -- were selected for additional information. Wet chemical analyses were calculated for the phosphorite interval using washed samples retained on a standard 200-mesh sieve (Table 2). A comparison of washed and unwashed samples from holes E34, E45 and E46 is shown in Table 3. Results of P2o5 content in unwashed samples are from Southern Testing and Research Laboratories; those from washed samples were furnished by the Department of Mines, Mining and Geology. The results are slightly erratic. Hole E45, for example, shows a general decrease in P2o5 upon removal of slimes of more than three percent. On the other hand, E46, located about one mile north of E45 (Plate I), showed nearly opposite results. Removal of slimes in these samples produced a general increase in P2o5 of more than four percent. With most of the samples there seems to be a relatively small percentage of P2o5 within the finer material. Continuation, Field and Laboratory Procedures 12 Table 2. Chemical analyses of washed, plus-200-mesh samples Phosphorite Hole interval P205 CaO Fe2o3 + Al2o3 Si02 ~Plate I) (feet) (percent) (percent) (percent) (percent) E45 25-30 12.51 17.90 2.06 30-35 11.13 17.70 2.41 35-40 9.94 14.70 1.56 40-45 11.82 18.20 3.22 45-50 11.77 18.00 1.75 50-55 13.20 20.20 2.63 55-60 8.07 11.50 1.64 60-65 8.39 12 .oo 555 61.21 64.32 70.91 60.71 64.97 59.11 75.57 67.80 E46 30-35 6.20 8.90 2.08 35-40 5.08 770 1.87 40-45 8.42 14.00 2 .30 45-50 11.06 16.00 1.94 50-55 12.25 18.20 1.61 55-60 13.29 21.40 1.95 6o-65 11.83 17.80 2.84 65-70 12.51 21.00 2.83 70-75 10.57 23.10 1.83 75-80 5.67 21.00 2.79 80.63 83.88 69.10 64.88 62.77 57.07 61.54 54.01 44.44 46.46 E54 20-25 1.48 1.88 3.71 25-30 1.47 2.05 2.12 30-35 1.85 2.65 1.00 3.5-40 6.17 9.10 1.89 40-45 6.42 9.90 1.39 45-50 6.61 9.80 1.37 50-55 9.90 15.10 1.78 55-60 11.61 17.80 2.48 60-65 11.80 18.80 2.09 65-70 8.06 16.60 1.03 70-75 4.88 10.70 1.63 84.82 91.11 93.12 79.56 79.36 78.68 67.12 61.46 59.60 60.71 71.86 E69 40-45 5.84 7 55 7.02 45-50 9.27 13.48 6 .92 50-55 7.87 ll.6o 5 .98 55-60 5.66 10.50 4 .25 60-65 3.69 13.88 2.18 65-70 3.42 15.55 2.70 69.39 60.52 66.44 69.07 59.06 53.10 Note: Determinations by J. R. Landrum, Georgia Department of Mines, Mining and Geology. Continuation, Field and Laboratory Procedures 13 Table 3. Comparison of percent P2o5 content in unwashed samples and washed phosphorite samples retained on a 200-mesh sieve Hole E34* E45 E46 Depth interval 70-75 75-80 25-30 30-35 35-40 40-45 45-50 50-55 55-60 60-65 30-35 35-40 40-45 45-50 50-55 55-60 60-65 65-70 70-75 75-80 Southern Testing unwashed 9.15 7.60 11.50 11.43 11.25 13.25 14.63 16.53 7.60 8.75 6.80 5.92 9.15 9.50 10.60 10.09 12.70 8.25 6.50 3.04 Georgia Department of Mines washed 12.61 10.03 12.51 11.13 9.94 11.82 11.77 13.20 8.07 8.39 6.20 5.08 8.42 11.06 12.25 13.29 11.83 12.51 10.57 5.67 Percent difference from unwashed +3.46 +2.73 +1.01 -0.30 -1.31 -1.43 -2.86 -3.33 +0.47 -0.36 -0.60 -0.84 -0.73 +1.56 +1.65 +3.20 -1.87 +4.26 +4.07 +2.63 *Comparison made only on highest P205 values within phosphate interval 45-85 feet in E34. Continuation, Field and Laboratory Procedures 14 The validity of obtaining drill cuttings versus cores was checked by FMC Corporation. Several holes were cored by FMC from top to bottom, some being offset less than 100 feet from a Southern Railway drill hole. The results of one comparison (Table 4) indicate less than two percent average variation between P2o5 values for the same intervals in cored and drilled holes. Southern Railway drill hole E3 showed an average 6.7 percent P2o5 for the upper half, compared to 5.3 percent for the same interval in FMC-2. The lower half of E3, with an average 5.9 percent P2o5, compared closely to the 5.8 percent for FMC-2. These averages indicate a slight increase in P2o5 as a result of obtaining drill cuttings rather than cores. Formational differences might account for the variation between the two holes. But it indicates more likely the probable absence of significant phosphate content in the slimes. Continuation, Field and Laboratory Procedures 15 Table 4. Comparison of core and cuttings analyses Southern Railway Drill Hole E3 35 FMC Corporation Core Hole FMC-2 Depth (feet) 40 - - - -- - - -- -- -- No assay No assay 50---------2~.8~- 55 8.6 35' @ 6 7% 60 -------------- 99 6.0 70 ------------------~-- 75 8 0 - -- - - -- -- -- - - -- 55 35 ' @ 90-------------- 5.9% 8.3 95 6.8 100------------- - - 105 8.75 41 1.80 44 46.5 1.25 1.6o 49 2 .13 535 3.12 56.5 11.88 59 .0 Lost --6o .0 --------- 35' @ 5.30% 8.88 63 70' 66 9.50 @ 68 .5 2.43 6. 3rvd;u ---------------- !~ .40 ~----------------~-- 6.18 73 557 755 775 7.38 4.00 -- 80 81 - - - -- -------=Lost 5.57 84 Lost 85.5 33.5' @ - - - -- -- -- - - - - -5 .28 5.80% 92 93 Lost 557 96 99 8.25 --------- - - -5.13 101 5.41 104.5 68 .5' @ 5 . 58'1> Note: FMC-2 data furnished through courtesy of FMC Corporation, Pocatello, Idaho . 16 GENERAL GEOLOGY The four-county area of investigation is located in extreme South Georgia along the Georgia-Florida state line (Figure 1). The area lies entirely within the Atlantic Coastal Plain and contains surface rock units ranging from approximately middle Miocene through middle Pleistocene in age. Pleistocene marine terrace materials blanket nearly the entire project area, but in most drill holes do not exceed ten feet in thickness. The occurrence of definite Pliocene age sediments in the study area has not been proven, mainly due to lack of any diagnostic fossils. In fact, the nearest known Pliocene material is located in the Occidental Corporation phosphate mine in Hamilton County, Florida (Plate I). The Hawthorn Formation of middle Miocene age is exposed in eastern Lowndes and western Echols Counties. Exposures along the Alapaha River at the Georgia-Florida state line may be older than the Hawthorn. The composition and distribution of the Miocene sediments in the study area are related to two main structural features. They are the Withlacoochee Anticline (Veatch and Stephenson, 1911, pp. 62-65) and the Southeast Georgia Embayment (Toulmin, 1955). From subsurface data the writer calculated for the Embayment an average regional dip of about ten feet per mile to the northeast. Sand- and silt-sized clastics were deposited on the east flank of the Withlacoochee Anticline (Plate V) in western Echols County. Increasing amounts of clay minerals were deposited to the northeast and east. Nearly all the streams in the four-county area flow into the Suwannee River which, in turn, flows into the Gulf of Mexico. The Alapaha River is the main tributary of the Suwannee. In southern Charlton County where the Continuation, General Geology 17 I \ I \ I. \ COLUMBUS o MACON ~ :c;. \.) n 0 0 ~ccoo ' f...... <: o LAKE CITY FIGURE I. SOUTH GEORGIA AND NORTH FLORIDA SHOWING AREA OF INVESTIGATION. Continuation, General Geology 18 drainage is controlled by the presence of Trail Ridge, streams flow toward the St. Mary's River. Tributaries to these major streams show a rectangular pattern, and even the Suwannee River shows a remarkable gross pattern of intersecting rectangular segments (Plate V). 19 STRATIGRAPHY General statement Lithologic units encountered in drill holes in the four-county area belong to the Oligocene, Miocene, Pliocene(?) and Pleistocene Series (Plate II). Phosphorite is found in varying amounts within nearly the entire Miocene sequence. Some near-surface, loosely consolidated, reworked sediments covering most of the area are thought to be post-Miocene by the writer. Pleistocene marine sands are thickest in Charlton County. The earliest geologic map of the Georgia Coastal Plain was produced by McCallie (1908). Various ages and names have been assigned since then to the formations exposed in the four-county project area. They are summa- rized from each of the authors' maps in Table 5. Veatch and Stephenson (1911), however, made the first subdivision of the Tertiar,y and Quaternary age sediments. They mapped most of the Lowndes-Echols-Clinch county area nearest the Florida line as Alum Bluff Formation (approximately late Oligocene age). They extended these exposures northward on their map along nearly all the stream valleys. The remainder of the three-county area was mapped as "Altamaha (Lafayette?) Formation (Pliocene?)." Charlton County is shown almost entirely as Pleistocene age material. The present State Geologic Map of Georgia (Cooke, in Stose and others, 1939) shows a large portion of the Coastal Plain as Hawthorn Formation. In Georgia no subdivision of the middle Miocene has been applied. Phosphatic material is found throughout the project area in those portions mapped as Hawthorn. A definite need exists for detailed work in stratigraphy, sedimentology and clay mineralogy of the broad area in Georgia covered by this Te.ble 5. Summary of mapped formations in project area System Quatel'Il!ZY Tertiary Series McCallie (1908) P~eistocene Veatch and Stephenson (1911) Okefenokee and SaUllA Fms. ~ Undi.fierentiated Oligocene, Miocene and Pliocene Altamaha (Iafeyette?) Fm. Miocene ~{ VicksburgJackson Fm.. Alum Bluff Fm. Chattahoochee Fm.. Vaughan and others, in Ste;pheneon o.nd Veatch (1914) Satilla and Okefenokee Fms. Undi.f'ferentiated Oligocene to Pleistocene inclusive Alum Bluff Fm. Chattahoochee Fm.. Sheaxer (1917) (Not mapped) Al.um Bl.ut'f Fm. Chattahoochee Ls. Cooke (1,943) Sunderlend Fm. (170') Coharie Fm. (215') Elavthorn Fm. Suwannee Ls. MacNeil (1947) Marine features (QJn:f') Older terraced surfaces (QP) Duplin Marl and Hawthorn Fm. (Mhd) Chipola Fm. and Tam1>a Ls. (Mtc) MacNeil (1950) Wicoodco Shore Line (100 1 ) Okefenokee Shore Line (15C' ) High terra.ce 0 0 8. 1-' [ 1-' ..:0.:s a ~ ....,. Otl 1-j i 1\) 0 Continuation, Stratigraphy 21 formation. Clay minerals investigations by Professor C. E. Weaver, Department of Earth Science, Georgia Institute of Technology (oral communication, 1966), should provide valuable clues to an understanding of the geologic events during Miocene time. Additional important subsurface exploration is in progress by the Mineral Engineering Branch, Georgia Institute of Technology. Their project is under contract from the State Department of Mines, Mining and Geology (Professor J. E. Husted, oral communication, 1965). A total of 13 holes, ranging in depth from about 120 to 300 feet, were drilled in four parallel alignments for stratigraphic and structural information (Plate I). A comparison of general lithology can be made from the driller's logs listed in Basic Data 2. Lower Miocene The aim in this study, for purposes of the Geologic cross-sections (Plate II), was to establish both surface and subsurface control on the phosphorite interval. Altitudes on selected holes easily provided the former, but a persistent "marker bed" was needed for the subsurface. The goal of each stratigraphic test was to obtain samples from the lower Miocene rocks. Fossils are scarce and so in this study the writer used a widely distributed dolomitic limestone. It is distinctive in its combination of being pale yellowish-brown, sucrosic, and hard; and in certain areas it is pitted (e.g., E6, CL2, CL3, CL6). Herrick (1961) and Applin and Applin (1964) also reported this lithology, at comparable depths, and in nearly all cases both authors placed it in the lower portion of the Miocene (Table 6). "Brown limestone" is also reported in the driller's logs for stratigraphic holes 114, E39, CL15, and LAl, but these have not been closely studied for comparison with the others. Author Modified from Herrick (1961) Count;z:: Well Charlton: GGS 93 Table 6. Summary of Tertiary subsurface data in Georgia from other reports Approximate altitude 120 Stratigraphic interval and thickness Pliocene to Recent Miocene undivided 0-82 = 82 82-270 = 188 Phosphatic interval 39- 50; 6o - 270 Yellowish-brown~ sucrosic, dolomitic limestone; lower Miocene(?)-Tam~(?) 220-236 Charlton: GGS 185 75 In Pliocene to Recent 90-100 = 10 115-258; Miocene undivided 100-455 = 355+ 278-430 No samples 455-517 = 72 Charlton: GGS 453 8o Pliocene to Recent Miocene undivided Upper Eocene 0- 120 = 120 120- 520 = 4oo 520-650 = 130 120- 310; 34o-380; 395-470; 500-520 Clinch: GGS 86 187 In Pliocene to Recent 10-100 = 90 40-160 Miocene undivided 100-180 = 8o 286-307 340-380 Not reported Clinch : GGS 124 187 In Miocene undivided 248-445 = 197 274-325; Oligocene undivided 445-520 = 75 350-36o 370-445 Echols: GGS 189 Lowndes: GGS 15 175 No samples 0-170 = 170 170-210 In Miocene undivided 170-245 = 75 Oligocene undivided 245-440 = 195 236 Pliocene to Recent 0-70 = 70 75-130 Miocene undivided 70-228 = 158 Oligocene undivided 228-375 = 147 210-220 205-228 Total denth 270 (In Miocene undi- vided) 554 (In upper Eocene Ocala Limestone) 650 (In upper Eocene Ocala Limestone) 180 (In Miocene undi- vided) 1,507 (In middle Eocene Claiborne Group) 4,100+ (In Tuscaloosa Formation) 425 (In upper Eocene Ocala Limestone) Note: All units of measurement are in feet; altitudes in feet above mean sea level. (Continued) 0 0 ~ 1-' ! 1-' 0 ~ a ~ 1-' ()Q ~ f-d ~ 1\) 1\) Author Modified :from Herrick (1961) Table 6 (Continued). Summary of' Tertiary subsurf'ace data in Georgia :from other reports County: Well Lowndes: GGS 27 Lowndes : GGS 40 Approximate altitude 250 Not listed stratigra:ohic interval and thickness In Pliocene to Recent Miocene undivided Oligocene undivided l0-6o = 50 60-180 = 120 180-380 = 200 Pliocene to Recent Miocene undivided 0-40 = 40 40-200 = l6o Phosphatic interval 6o-100 Yellowish-brown, sucrosic, dolomitic limestone; lower Miocene(?)-Tam~(?) l40-l8o 40-100 Not reported Lowndes: GGS 42 Lowndes: GGS 47 Lowndes: GGS 78 Lowndes : GGS 79 Lowndes: GGS 173 Lowndes: GGS 179 Not listed Not listed 251 250 230 145 Pliocene to Recent Miocene undivided Oligocene undivided In Pliocene to Recent Miocene undivided 0-40 = 40 40-l6o = 120 l6o-220 = 6o 10-20 = 10 20-220 = 200 Pliocene to Recent Miocene undivided In Oligocene undivided Pliocene to Recent Miocene undivided In Oligocene undivided Pliocene to Recent Miocene undivided Oligocene undivided Pliocene to Recent Miocene(?) undivided No samples In Oligocene undivided 0-6o = 6o 6o-l80 = 120 180-278 = 98 0-40 = 40 40-l8o = 140 180-200 = 20 0-90 = 90 90-195 = 105 195-370 = 175 0-6o = 6o 6o-75 = 15 75-95 = 20 95-208 = 113 (Continued) 40-140 20-100 6o-8o; 100-140 50-90; 120-180 90-110 No phosphate Not reported 120-220 Not reported 180-200 190-205 Not reported Total deuth 400 (In upper Eocene Ocala Limestone) 200 (In Miocene undi- vided) 220 (In Oligocene undivided) 220 (In Oligocene undivided) 278 (In Oligocene undivided) 200 (In Oligocene undivided) 818 (In middle Eocene Claiborne Group) 2o8 (In Oligocene undivided) 0 0 ~ 1-' [ 1-' '- a ~ 1-' Otl ~ ~ [\) l.Al Author Modified from Herrick (1961) Table 6 (Continued). Summacy of Tertiacy subsurface data in Georgia from other reports County: Well Lowndes : GGS 182 Lowndes: GGS 198 Lowndes: GGS 35q Approximate altitude 202 stratigra;2hic interval and thickness Pliocene to Recent Miocene undivided Oligocene undivided 0-45 = 45 45-175 = 130 175-248 = 73 Not listed Not listed No samples In Miocene undivided Oligocene undivided Pliocene to Recent Miocene undivided 0-176 = 176 176- 207 = 31 207-361 = 154 0-55 = 55 55-150 = 95 Phosphatic interval 55-70; 95-115 No samples Yellowish-brown, sucrosic, dolomitic limestone; lower Miocene{?)-Tampa(?) 150 - 160; 175-200 (Gradational contact with Oligocene?) 192 -207 60-100 140-150+? Lowndes: GGS 4o4 Lowndes: GGS 412 Lowndes: GGS 500 Lowndes : GGS 511 Not listed 250 250 Not listed Pliocene to Recent Miocene undivided Oligocene undivided Pliocene to Recent Miocene undivided Oligocene undivided Pliocene to Recent Miocene undivi ded Oligocene undivided Pliocene to Recent Miocene undivided No samples In Oligocene undivided 0-52 = 52 52-180 = 128 180-316 = 136 0-70 = 70 70-236 = 166 236-363 - 127 0-50 = 50 50-180 = 130 180-375 = 195 0- 70 = 70 70-210 = 140 210-220 = 10 220-375 = 155 ( Continued ) 60-107 70-118 ; 123-175 50-100 70 - 80 150-160 207-226 170-180 190-210; 210 -220 (No samples) Total depth 248 (In Oligocene undivided) 361 (In Oligocene undivided) 150 (In Miocene undi- vided) 316 (In Oligocene undivided) 500 (In upper Eocene Ocala Limestone) 400 (In upper Eocene Ocala Limestone) 4oo (In upper Eocene Ocala Limestone) 0 0 8- f-J l 1-' 0 ..:.:::s a ~ 1-' (JQ i [\) + 0 0 8. 1-' [ 1-' :0:s "' ~ li ~ 1-' (J'q li Ill Table 6 (Concluded). Summary of Tertiary subsurface data in Georgia from other reports ~ "< Author County: Well Approximate ~ Stratigraphic interval and thiclmess Phosphatic interval Yellowish-brown, sucrosic, dolomitic limestone; lower Miocene(?)-Tampa(?) Total depth Modified from Applin and Applin (1964) Charlton: GGS 185 75 No samples 0-90 = 90 ll5-125; Absent (may be present 554 In Miocene undivided 90-416 = 326 138-416 at 416-430) (In upper Eocene Oligocene absent Ocala Limestone) No samples 416-430 ~ 14 No samples: Upper Eocene 430-554 = 124 0-90, 128-138; 149-158; 215-225, 3l7-327; 416-430 Lowndes: GGS 182 202 Miocene undivided 5-165 ~ l6o Absent Lower Miocene (Tampe Limestone) 165-190 ~ 25 Upper Oligocene 190-205 = 15 No samples 205-248 = 43 165-190 (Four faunal types present) 248 (In upper Oligo- cene Suwannee Limestone) [\) \Jl Continuation, Stratigraphy 26 The dolomitic limestone unit is probably the equivalent of the Tampa Formation, but only in part. The top of the lower Miocene, then, may well be above the dolomitic limestone, but further evidence, based in part on paleontology and sedimentology, is needed. Herrick and Vorhis (1963, p. 66) commented on a carbonate rock unit overlying the dolomitic limestone as follows: ''The age of the phosphate-bearing limestone at the base of the Miocene in southeastern Georgia and adjacent parts of South Carolina is uncertain." The authors feel there is a possibility of its being late Oligocene. Subsurface descriptions by Herrick (1961) and Applin and Applin (1964) on the lower Miocene were checked by the writer and are summarized for the area as a part of Table 6. Middle Miocene(?) "Hawthorn" Formation Cooke (1944) extended the name "Hawthorn" Formation into Georgia from already established localities in Florida. Prior to Cooke's work, the accepted geologic map (Veatch and Stephenson, 1911) showed most of the project area as Altamaha (Lafayette?) Formation of Pliocene(?) age. The sedimentary sequence was possibly already in its first stage of controversy. Dall (1892) applied the name "Hawthorne beds" to several Miocene exposures,earlier described in part by L. C. Johnson, in the vicinity of Hawthorne, Florida. Puri and Vernon (1964, p. 145) pointed out that there is no valid type locality for the Hawthorn Formation. They considered the sections at Devil's Mill Hopper (Alachua County) and Brooks Sink (Bradford County) as being "closest to the type area and should fonn the basis of later correlation." A minor point is that the town of Hawthorne (Alachua County) now uses the original spelling that Dall applied when he first proposed the rock unit name. Continuation, Stratigraphy 27 Puri (1953, p. 38) in his study of the Florida panhandle, divided the entire Miocene sequence into three stages -- Tampa, Alum Bluff and Choctawhatchee --from oldest to youngest. The Alum Bluff, .bounded by unconformities, is further subdivided into four lithofacies -- Hawthorn, Chipola, Oak Grove and Shoal River. The Chipola is considered the downdip, or marine, equivalent of the nonmarine Hawthorn. According to Keroher and others (1966, p. 779), the preferred usage is Chipola Formation (of the Alum Bluff Group), and it is considered lower Miocene in age. In later studies of North Florida, Espenshade and Spencer (1963) described the upper portion of the Hawthorn as terrestrial, the lower part as marine. Age Druid Wilson, Miocene specialist for the Paleontology and Stratigraphy Branch, U. S. Geological Survey (personal communication, 1966), has evidence for a possible early Miocene age for the Hawthorn and Chipola Formations. Lithology The Hawthorn Formation everywhere at the surface consists of weathered sandy clays and clayey sands. They are mottled in various hues of red, purple, yellow and brown because of varying amounts and types of iron oxide left by the ground water, the principal agent during decomposition. Within the four-county area the total thickness of the Hawthorn can best be generalized from the stratigraphic test holes (Plate I). The thickness ranges from 100 feet to more than 275 feet. Lithologic descriptions are given in Basic Data 2. An isopach map prepared by Toulmin (1952, p. 1173) shows the total thickness of the Miocene sediments increasing from about 150 feet in Lowndes County to about 350 feet in Charlton County. Continuation, Stratigraphy 28 Clay minerals (-200 mesh fraction) from a few cores in eastern Echols and southern Clinch Counties were identified by X-ray diffraction (J. B. Cathcart, written communication, 1965). Montmorillonite was found to be predominant in CL38 but minor in E34 (Plate I). South of Fargo minor amounts of attapulgite and mixed-layer attapulgite and montmorillonite were found in CL36 and CL37. Near the surface and in outcrops the montmorillonite has been altered to kaolinite. Dolomite was reported as significant in E34, CL36 and CL37. Quartz was present in all samples checked, but apatite was absent except for a trace in CL36 and CL38. Quartz sand is almost universally found within the carbonate sequences as well as the predominantly clay intervals. The quartz grains are clear, generallY subangular to subrounded, and are mostly medium-grained (~-i mm) to coarse-grained (1-~ mm). The sand grains are well sorted, typical of a beach sand. When found in the limestone and dolomite layers, these grains are generallY abundant and notably coarse-grained. The pitted surface of the drill cuttings is most likelY due to removal of the quartz. Limestone and dolomitic limestone are common within the lower portion of the Hawthorn. Much of the limestone is very friable, and when wetted is quite pasty in texture and appearance. Dolomitic limestone, within the lower part of the Hawthorn is typicallY harder. Interlaminated silty limestone and clear quartz grains were noted in CL2 between 145 and 170 feet (note description in Basic Data 2). Thin, apparently discontinuous, layers less than one foot thick are found beginning in the middle portion. Chert was noted in at least 17 drill holes, and in all but two of them the first influx of chert in the cuttings occurred before any limestone was encountered. The thickness of these layers varied from a few inches to about two feet. Continuation, Stratigraphy 29 Distribution The Hawthorn Formation is exposed within the four-county area only in southeastern and western Lowndes County, and in the western one-third of Echols County. However, it was encountered in the subsurface in all drill holes except most of those drilled in Charlton County. In Figure 2, a generalized section (D-D') shows the distribution of the predominant lithology from eastern Lowndes County to the Okefenokee Swamp. Quartz sand with minor amounts of clay is common in western Echols County and a few parts of eastern Lowndes County. East of Haylow (Plate I and Figure 2), the quartz sand content diminishes and does not increase eastward until its irregular presence east of Headlight in holes CL5 and CLl5. Distribution of individual species of clay minerals is beyond the scope of this report, but some cursory observations can be made in addition to the few X-ray determinations. In the western portion of the study area (Figure 2), kaolinite (at or near the surface) and montmorillonite appear to be dominant. In the eastern portion, these same minerals are present with the addition of mixed-layer montmorillonite and attapulgite. In El and CL3 green, non-plastic clay, with gross properties similar to those of known attapulgite, was noted below 225 feet. Limestone layers were encountered in portions of southwestern Echols and southeastern Lowndes Counties at depths of 45 to 50 feet. Thin lime- stone beds can be seen exposed during the dry season of the year along the Alapaha River west of Statenville. In the eastern portion of the project area, the uppermost limestone layers occur between 6o and 80 feet below the surface. Massive limestone was encountered in the eastern portion in the deeper stratigraphic test holes at variable depths from 75 to 155 feet. "0 ' 0 "' 0 u.s. HIGHWAY .. 1 :: :jf MUD CREEK LOWNDES COUNTY --------....:.-=-=-sTATF""'Roii'r~- - - ECHOLS COUNTY ..;:: z"' ll:i i~iii !iMIIJ E 52 r ALAAHA RIVER PORTION PORTION GA. .""'' - - - -- ECHOLS - - - - COUNTY - CLINCH COUNTY 19 17 '"O;:El>Ul"Tl ::Omz:XG) OU)OOc I- I::l0l C"l;:uUlZ --iz"'l>g::o ::UZj;;pg lllO--il>l> l>rrl~:jg: "l> 'rz0s:l:> --i::jUl;:: "" ::0 : x0 : : :!: "[J J->-i z5"'n ~'"O- o0 l: ,;= ""...,''""'' 5 CL 4 # CLI6 ~--- CL14 CLI3 RY GA. - - - - - - - - - - - - - U,S. HIGHWAY 441 1----- CL15 - -- - - -- - - -- - - - - TATUM CREEK '~ ,, II t ' 11 ll 1::: c p~ ~ ~ l> z z , ,"X..0. )> z .J-.('''dil'l'l'n!~- , - - -- - --- CL 35 - - - --- SUWANNE E CAEE K ~ -< ~ 0 d z "' r 0 !( -l->i 0 z _ _ C.!: INCH ~ ~- - - WARE COUNTY - - - - - - - "OKEFENOKEE NATIONAL ,z 0 REFUGE I 0 0 0 0 0 "0 ' "0 ' 0 0 Continuation, Stratigraphy 31 Upper Miocene The presence of late Miocene age material has been determined more successfully from vertebrate rather than invertebrate fossil remains. Late Miocene fossils which are nearest to the Georgia state line were reported by Olsen (1963) and Yon (1965). They discovered fossil mammal teeth near Ashville, in northeastern Jefferson County, Florida, about three miles south of the Georgia-Florida state line. Approximately 30 horse teeth (Merychippus sp.) and one rhinoceras molar (Diceratherium sp .) were identi- fied by Olsen as late Miocene in age. Yon (1965, p. 169) has related that "they are important because they represent the only known late Miocene vertebrate locality in Florida." Post-Miocene Unconsolidated Pleistocene quartz sand is distributed over nearly the entire project area (Cooke, 1943). The clear quartz grains are a typically well sorted beach sand, and contain accessory amounts of feldspar and kaolin near the surface. In Lowndes, Echols and Clinch Counties, the material is of a fairly uniform thickness, averaging 10 feet. In Charlton County this sand occupies probably the upper 40 feet; sediments in the lower portion of the holes conform to the descriptions given by Herrick (1965, p. 7) as Pliocene(?) age material. The top of the Miocene in this area northwest of St. George is apparently 100 feet or more beneath land surface. 32 STRUCTURE General statement Two structural elements, the Withlacoochee Anticline and the Southeast Georgia Embayment are noted within the four-county area. A minor anticlinal fold with a north-south axial trace may be present at Statenville (Plate V). Relationship of the positive structural features to the Ocala uplift is discussed. A detailed structural analysis is considered beyond the scope of this report, but future work combining careful stratigraphic correlation and geophysical work is considered highly desirable. Veatch suspected structural deformation in the southern Georgia Coastal Plain (Veatch and Stephenson, 1911, pp. 62-65). He was the first to record his observations of the interrelationship of geologic structure to present-day stream patterns and selected altitudes in this area. "There is also physiographic and geologic evidence of a low fold or arch . in the area drained by Ocklockonee, Withlacoochee and Alapaha Rivers, and extending along the Florida line from Decatur to Echols Counties and northward to Crisp and Wilcox Counties." Veatch named this feature the Withlacoochee Anticline for the river which forms the western boundary of Lowndes County and flows southward along the middle of the fold (Plate V). Pressler (1947, p. 1853) designated an anticline with a southeast- ward plunge which he called the Central Georgia uplift. He located the axial trace on his map to the east of the Withlacoochee Anticline. Pressler related, from north to south, the Central Georgia uplift and Ocala uplift to the eastern rim islands of the Bahama group. The latter he termed the Bahama uplift. Continuation, Structure 33 The major negative feature in southeast Georgia has been known by various names. Pressler (1947) used the term Okefenokee Embayment for a part of the area, and stated that it "is probably a part of a more pro- nounced downwarped area or embayment at the north." Toulmin (1955, p. 209) named the structure the Southeast Georgia Embayment. Herrick and Vorhis (1963, p. 55) proposed the name Atlantic Embayment of Georgia, based upon the similarity of its fossils to the present Atlantic Ocean assemblage. The writer prefers Southeast Georgia Embayment which not only includes the entire structural feature but also is a slightly shorter term. Formations throughout the project area have a very low dip, generally to the east and northeast, and all at considerably less than one-half degree. Apparent dips ranging from 4.0 to 11.9 feet per mile to the northeast were calculated for the lower portion of the Miocene in eastern Echols and southern Clinch Counties. This range is slightly greater than the general- ized dip given for the top of the Oligocene (Herrick and Vorhis, 1963, p. 56). The top of the widely distributed yellowish-brown, sucrosic, dolomitic limestone unit was used as a datum (Table 6). The writer recognizes that this limestone could well be a lithofacies of one or more time-rock units to the west. In fact, it is almost certain that this area, in particular, is not one of simple, stratiform lithologies. Such dips are therefore subject to revision with more detailed work. Withlacoochee Anticline As surface indicators of a geologic structure, anomalous stream patterns are certainly not conclusive, but structure does influence the geomorphology of an area. Therefore, Veatch was employing a geologic tool that is still useful today. In addition, Herrick and Vorhis (1963, p. 12) show a positive Continuation, Structure 34 area, coinciding with the Withlacoochee Anticline, on their structure contour map of the top of the Oligocene rocks. In this investigation the absence of phosphorite in northeastern Lowndes County (Plate I -- holes L6, L7, Ll3, and Ll4) is also significant. Circulation of drilling fluid was lost in Ll3 and at a depth of 155 feet or a~ altitude of 70 feet. This altitude compares favorably as being the top of the Oligocene when placed upon the structure contour map of Herrick and Vorhis. In addition, Herrick (oral communication, 1966) identified the top of the Oligocene in drill hole E45 at a depth of 100 feet (Plate II). A chronological sequence of structure contour maps by Herrick and Vorhis (1963) shows the following changes: (l) By the end of middle Eocene time (p. 26), there was a south- west plunging syncline, with an east flank passing through northwestern Lowndes and eastern Brooks Counties. (2) By the end of late Eocene time (p. 20), the axial trace of the middle Eocene syncline is shown as merely a ''sag," or slightly depressed feature. The present-day course of the Withlacoochee River is located in this "sag." (3) At the end of late Oligocene time (p. 12) the area included within Veatch's Withlacoochee Anticline was positive, except for a breached area in southern Brooks County. A convergence of two "zero line" contours is at about the northern tenninus as noted by Veatch (1911, p. 63). Continuation, Structure 35 Southeast Georgia Embayment This negative feature persisted the longest, and has remained consist- ently the largest, of any structural feature known in the Georgia Coastal Plain. Herrick and Vorhis (1963, p. 55) reported that on the basis of available evidence the Embayment 11appears to have originated in middle Eocene time and continued as a depositional basin intermittently through Miocene time. 11 The general dip of the sedimentary units to the east and northeast in Lowndes, Echols and Clinch Counties is because of the Southeast Georgia Embayment, the axis of which is northeast of the project area (Plate V). Minor fold At the west city limits of Statenville (Echols County), and southward along the Alapaha River, phosphorite is not only exposed, but partially eroded. It is also exposed in the banks of the Withlacoochee River on the western Lowndes County line south of Clyattville. Phosphorite is also exposed in those areas where meanders of the Suwannee River have become incised. If, indeed, the Withlacoochee River is flowing parallel to the axial trace of an anticline, then it is quite possible that the Alapaha River is doing likewise along an associated minor fold. Southward dips of 10 to 12 degrees can be recorded on thin-bedded limestone units at low water mark along the Alapaha River. These, however, are not true dips. The limestones crop out below the phosphorite, and the entire sequence is massively cross-bedded. Accurate structural data from these exposures are very difficult to obtain. Continuation, Structure 36 Preparation of a detailed structure map will help determine whether the Alapaha River is truly structurally controlled, or whether geomorphic processes have produced apparent relief in the phosphorite beds. An additional possibility is that all or part of the Alapaha River phosphorite is Pliocene, representing beds at or near the western limit of deposition. Relations to Ocala uplift In counties adjoining the project area, structural data from Georgia of Herrick and Vorhis (1963) may be compared with that of two Florida investigators. Meyer (1963, p. 23) presented somewhat generalized cross-sections for Columbia County. This county adjoins southeastern Echols County and most of Clinch County. Meyer also showed on a structure map (Figure 9, p. 28) the top of beds of late Eocene age. A comparison with the similar map of Herrick and Vorhis (1963, p. 20) shows the waning influence of the Ocala uplift from Lake City northward. This is probably the reason for the reduction in slope of the southwest portion of the Southeast Georgia Embayment. Meyer also stated (p. 22) that for central Columbia County, 11The thickening of beds of Miocene age northward suggests that uplift and contemporaneous deposition took place during post-Eocene time. 11 Vernon (1951, Plate 2) showed on his structure map the configuration of the Inglis Member, Moodys Branch Formation (Lower Jackson Group). No similar data for Georgia exist, but some structural trends can be projected into Georgia from Vernon's map and cross-sections (Figure 13, p. 54). For example, the Withlacoochee Anticline appears to be the northward extension of the main axial trace of the Ocala uplift. Another comparison shows structural highs west of Lake City and White Springs (Columbia County) and Continuation, Structure 37 just west of High Springs (Alachua County) -- shown in Sections A-A' and B-B' (Figure 13) and depicted on the structure map (Plate 2). This northward-plunging minor fold from the Ocala uplift can be projected directly into the Statenville area. The axial trace, roughly parallel to the Alapaha River, becomes that of the minor fold previously noted by the writer. GEOMORPHOLOGY General statement The four-county area studied lies within the Coastal Terraces physio- graphic division of Georgia (Cooke, 1925, p. 17). Altitudes range from greater than 225 feet in eastern Lowndes County to about 100 feet in southeastern Clinch County. The latter area, on the southwest edge of the Okefenokee Swamp, may be considered local base level. Within the study area, karst topography prevails in southeastern Lowndes and southwestern Echols Counties. Most of the entire project area is poorly drained, and generally of very low relief. Dominant physical features which provide clues to the occurrence of phosphorite in the South Georgia-North Florida area are sinkholes produced by solution of the underlying Suwannee Limestone of Oligocene age. Brief discussions are presented also concerning subsurface cavities and unusual thicknesses of phosphorite, stream patterns, and the influence of Trail Ridge in Charlton County. Relations of karst topography to phosphorite occurrence A careful inspection of the Valdosta sheet (USGS, 1:250,000), from which Plate I is taken, reveals an interesting pattern of lakes. The Georgia Southern and Florida Railway between Valdosta and Lake City forms a dividing line between a well-developed karst topography, containing abundant lakes, to the southwest; and a sharply decreased number of lakes and sinkholes to the northeast (C. W. Sever, oral communication, 1965). The significant commercial phosphate discoveries so far have been made along a linear trend which parallels the northeast side of the railroad from south of Jasper, Florida, southward into Union and Bradford Counties. Continuation, Geomorphology 39 Northward into Georgia, however, the pattern o~ lakes ends almost abruptly about ~ive miles north o~ Valdosta. The rather discontinuous occurrences o~ commercial phosphorite take an apparent northward trend at about the intersection o~ the Alapaha River and the Georgia-Florida state line. Subsur~ace cavities and unusual phosphorite thicknesses Northeast o~ the Georgia Southern and Florida Railway more solution cavities were encountered but in the subs~ace. In western Echols and eastern Lowndes Counties, the phosphorite was deposited upon the eroded sur~ace o~ the Suwannee Limestone. There is little or no evidence o~ any lower Miocene or Tampa Formation equivalent present in this part o~ the study area. Circulation o~ drilling ~luid was lost in six drill holes, and only one (CL2) was located in the eastern portion o~ the project area. Excessive localized accumulations o~ phosphorite, interpreted as possible ~illings in solution cavities and channels, were concentrated in the same western Echols-eastern Lowndes county area. Signi~icantly, the phosphorite in holes adjacent to those mentioned was less than one-third as thick, or else a nearby hole was barren. Table 7 lists drill holes in which lost circulation occurred, and also those in which unusual thicknesses o~ phosphorite were ~ound. Stream patterns Many observers have already noted the peculiar course o~ the Suwannee River. It heads in Oke~enokee Swamp, ~lows generally S45W to a point a ~ew miles south o~ the Georgia-Florida state line. Here its course changes rather abruptly to about S35E ~or approximately 12 miles, and then returns Continuation, Geomorphology 40 Table 7 Solution cavities and probable cavity fillings encountered in drill holes Drill hole LlO Ll3 El8 E32 E33 E37 E4l E44 E46 E49 E54 E59 E73 E74 E77 CI2 Depth of lost circulation (feet) 155 118 75 71 56 302 Anomalous thickness of phosphorite (feet) 45 52 65* 62 57 80* 55 55 50 42* *Indicates thickness greater than that shown. Continuation, Geomorphology 41 to a southwesterly direction. Lineaments drawn for the Suwannee and its tributaries on the USGS Valdosta sheet (1:250,000) show a pronounced rectangular drainage (Plate V). Over the crest of the Ocala uplift, the fault traces shown by Vernon in west-central Florida have a bearing of N45W (Vernon, 1951, Plate 2). Portions of the Suwannee and its tributaries in South Georgia and extreme North Florida, which divert a general southwesterly flow, have a bearing of approximately N35W. These same diversions change to about N55W farther south. It is a well-known fact that joints, sinkholes and solution channels are commonly related in certain types of limestones. Limestone brought nearer to the surface by the Ocala uplift has become (l) fractured, and (2) dissolved. The map pattern of the Suwannee and its tributaries has been controlled quite likely by structural activity related to the Ocala uplift, and also by formation of joints (Plate V). Other investigations Professor H. K. Brooks (oral communication, 1966) has recently constructed a topographic relief model at the University of Florida of a portion of the North Florida-South Georgia area. The horizontal scale is approximately 1:125,000. The model reveals clearly the incised meanders of the Suwannee River and associated straths, or valleys deeply filled with alluvial deposits. Brooks has determined that the better phosphorite deposits are in areas near the Suwannee River associated with these straths. He has hypothesized an opposite former direction of flow for the Suwannee, based upon his studies. His evidence indicates that the topography of the region is very old, and that it has been little modified since early Pliocene time. Continuation, Geomorphology 42 Influence of Trail Ridge In Charlton County l2 holes were drilled to depths of 75 and 90 feet (Plate I). Driller's logs (Basic Data 2) compare favorably with lithologic sequences for the area shown by Herrick (1965, pp. 4-5). For example, the top of the coquina zone, near the bottom of drill holes CH3 and CH4, was encountered at about the same altitude as noted by Herrick as Pliocene(?) in his Section B-B' Therefore, many of the other so-called '.'barren holes" in Charlton County (Plate I) are probably entirely within post-Miocene sediments. Calver and Vernon (1949) stated that the high sand ridge, which includes Trail Ridge and the central highlands to the south, was originally a Pleistocene barrier island or similar feature. Trail Ridge, however, is now only a remnant of part of a delta plain and coastal geomorphologic complex, according to the authors. 43 PHOSPHORITE General statement Hard, concretionary phosphate in Georgia was first reported by J. W. Spencer, the third State Geologist, to the Governor in 1890. Commercial mining at the locality, three miles west of Boston (Thomas County), began in 1891 (Spencer, 1891, p. 82). McCallie later published a phosphate report on the entire South Georgia area in 1896. ~cCallie (1896, p. 94) concluded that other economic deposits were not likely in this area. Veatch and Stephenson (1911, p. 346) noted deposits of phosphate sand along the lower courses of the Suwannee and Alapaha Rivers and indicated that these deposits might someday be a source of low grade material. Mansfield (1942) and Espenshade and Spencer (1963) showed phosphate in Hamilton County, Florida, just south of the Georgia state line. Phosphate particles are present in the Hawthorn Formation of middle Miocene age over a large area of South Georgia. Professor H. K. Brooks (oral communication, 1966) has pointed out that the phosphorite at Staten- ville is late Miocene, or possibly even Pliocene, in age. He has collected Pliocene land vertebrate remains from various localities in North Florida. Brooks previously had correlated on the basis of distinctive sedimentology and topographic relations, the phosphorite in the Occidental Corporation mine from the then known Pliocene (Plate I). This has recently been confirmed by the Neohipparion tooth collected by Professor David Webb, Univer- sity of Florida. G. F. Moulton, Jr. (oral communication, 1965) located another Pliocene horse tooth from within a phosphorite core at 35 feet below land surface, two miles due north of Lulu, Florida (Plate I). Continuation, Phosphorite 44 Beds of possibly economic phosphorite, that is, containing more than nine percent P2o5, in unwashed samples, are common in western Echols and eastern Lowndes Counties. Similar beds are uncommon or absent in the remainder of the four-county area. As a matter of convenience, U. S. Highway 129, north-south through Statenville (Plate I), will be a boundary separating the western and eastern portions of the four-county area. By this designation, phosphorite in these two parts will be contrasted (Figure 2). Western portion Gray and yellowish-brown phosphate deposits of marginal commercial grade occur within clear quartz sand intervals. Percentages of P2o5 are listed under Basic Datal and on the cross-sections (Plate II). Although many of the drill holes contain some economic phosphorite, there is one striking linear arrangement of such holes about four miles west of Statenville (Plate I). From north to south, they are holes E54, E46, E45, E62, and E69 (see Basic Datal for analyses). The nearest holes to all sides of this somewhat arcuate alignment contain phosphorite in reduced thickness, and in nearly all cases the phosphate particles are non-commercial. Rapid changes in thickness of the phosphorite in the eastern Lowndeswestern Echols area are shown in Plate II. Pebbles of quartz and phosphate within the same zones are abraded and sub-rounded. Some holes display two distinct zones of phosphorite. An upper zone is associated with relatively unconsolidated quartz sand with minor amounts of clay minerals. A lower zone is characterized by finer grained phosphate particles embedded in sandy clay or dolomitic limestone. It is possible that in these holes both Miocene and Pliocene phosphate particles are present. Continuation, Phosphorite Pebble-sized phosphate particles, retained on a 20-mesh screen, are typical of the western portion but are still uncommon. Where present, they are generally no more than 5 to 10 percent by volume in a sample, and ordinarily less than 5 percent. These pebble zones are commonly associated with coarse-grained quartz sand and pebbles which are rounded and translucent. In some cases, the phosphate pebbles have inner cores of pitted phosphatic limestone and merely an outer rim of concentrated phosphatic material. In other instances a broken phosphate pebble reveals small clear quartz grains. Both types contain impurities which lower the P2o5 content considerably. A discussion of weathering and secondary zonation of the phosphate pebbles and finer clastics has been presented by several authors for the west-central Florida district. A recent one, given by Altschuler and others (1964, pp. 34-36), may be applied to the South Georgia area as well. Fine feed material, that is, passing a 35-mesh and retained on a 200mesh screen, is the prevalent size grade in the western portion. The average concentration of these particles in the samples is about 10 to 15 percent by volume. The volume of slimes (-200 mesh) varies widely in the samples, from 5 to more than 90 percent. An approximate weighted average, for the western portion, however, is about 20 percent based upon clay data from tests made by the Mineral Engineering Branch, Georgia Institute of Technology, for Project Report No. 2 (Husted and others, pp. 25-29). East of Statenville the clay minerals increase in volume and total thickness. The writer made no quantitative determinations of relative volume of slimes to the coarser fractions. Continuation, Phosphorite 46 Phosphorite overburden ranges in thickness from zero, in exposures along the Alapaha River south of Statenville, to 70 feet in drill holes L5, LB, and L9, all located within six miles east of Valdosta (Plate III). Thickness of the phosphorite itself is quite variable, and ranges from zero, in stratigraphic test holes L6, Ll3, and Ll4 -- all north and east of Valdosta -- to more than 80 feet in E4l near the Echols-Lowndes county line just south of State Route 94 (Plate IV). An average range of thickness for the phosphorite in this portion is 20 to 40 feet. As already mentioned, clear quartz sand is the predominant associated lithology in the zones containing commercial phosphate. In other holes there appears to be a direct relationship between increasing amounts of clay, identified as montmorillonite in several drill holes (Cathcart, written communication, 1965), and the lower grade phosphate. These phosphate pellets are generally black instead of gray or brown. Some phosphate particles are embedded in limestone, but the volume concentration within a given sample is minor. The grain size and lateral distribution of the phosphate and its associated clastic material indicates deposition in an agitated, probably nearshore environment. On a sub-regional scale, the commercial phosphate deposits in South Georgia and North Florida are oriented northwest-southeast in a linear pattern which closely coincides with the alignment of the Georgia Southern and Florida Railway. It is quite possible this linear feature represents a middle Miocene (and possibly later) strand line upon which the coarse-grained quartz sand and phosphate were deposited. The quartz particles in the area of investigation are of nearly uniform size, representing a typical well-sorted beach sand. Along the Alapaha River in the vicinity Continuation, Phosphorite 47 of Statenville, phosphorite exposures contain shark teeth and poorly preserved marine shell fragments which further attest to the marine environment. These clastics accumulated along the gently dipping east flank of the Withlacoochee Anticline (Veatch and Stephenson, 1911, p. 63), and a postu- lated parallel flexure to the east (Plate V). Phosphorite in this western portion was deposited upon a limestone surface which probably already contained many solution cavities and channels. Intertidal wave action, followed by active ground-water movement, was apparently the final agency to act upon the material. Eastern portion Fine-grained black phosphate particles are embedded in bluish-green, plastic, sandy clays throughout most of this portion of the project area (Figure 2). Very few drill holes were found containing economic phosphorite zones east and northeast of Statenville. The concentration of phosphate particles is notably lower than in the western portion; of the holes selected for P2o5 analyses on the basis of adequate concentration, only E2 and CL8 in the vicinity of Fargo (Plate I) showed zones of commercial phosphate (analyses in Basic Data 1). Practically no pebble-sized phosphate (+20 mesh) was encountered in the holes of the eastern portion. A minor amount of pebble was noted, however, in thin zones below 100 feet in some of the stratigraphic test holes. Fine feed material is the dominant size grade. The higher concentrations of phosphate particles are confined primarily to the layers of sandy clay and loosely consolidated sandstone. The average concentration of phosphate within a given sample is about 10 percent by volume. Continuation, Phosphorite 48 In drill holes showing phosphorite, the overburden thickens from 25 feet in drill holes E2 and CL3 west of Fargo, and in E7 and El5 west of Haylow, to 80 feet in CL25 south of Thelma (Plate III). It is quite certain that many of the 90-foot drill holes which were barren in the eastern portion would have encountered phosphorite had they been drilled deeper. The phosphorite ranges in thickness from zero (note symbols for the barren holes on Plate I) to 137 feet in CL2 northwest of Headlight, and 145 feet in El west of Fargo (Plate IV). The phosphate and its associated sediments were deposited in a marine shelf environment that underwent several pulsations of relative subsidence and uplift. The controlling structural feature was the Southeast Georgia Embayment (Plate V) which had its axis to the northeast. In the early stages of phosphorite development there was alternate deposition of limestone and minor amounts of marl, with claystone and variable amounts of silt and sand. During the later stages, the phosphate particles were deposited more commonly with silty and sandy claystone and also some sandstone. In this later sequence limestone and phosphatic limestone were deposited in lenses or thin layers. Figure 2 summarizes the relationships of overburden and phosphorite between the western and eastern portions of the four-county area. Section D-D 1 shows the progressive decline in altitude of the top of the phosphorite from west to east. The upper contact in the western portion is between 100 and 150 feet above sea level, and in the extreme eastern portion it is between 50 and 75 feet. Throughout the project area, information gained from conventional phosphate drill holes and deeper stratigraphic test holes Continuation, Phosphorite shows a marked thickening of both overburden and phosphorite from southwest to northeast. The result can be described generally as a downward-tilted wedge of phosphorite. Relationships among color, grade and mineralogy Comments from geologists, mining engineers and others range from doubt- ful to certain when one discusses the relationship of percent P2o5 to color of the phosphate. Several observations which can be made are as follows: (l) Colors of the phosphate particles are black, brown, yellowish-brown, various shades of gray, and white or nearly white. Particles are not necessarily segregated within the formation on the basis of color, for more than one color may be associated within the same depth interval. (2) Lighter tints are uncommon in the subsurface but common to abundant in the phosphorite exposures. Some light colored material, however, was found in this study at a depth greater than 100 feet in relatively thin layers associated with clear, coarse-grained quartz sand. (3) Almost without exception the phosphate embedded in clay minerals is black; that associated with coarse-grained to pebbly quartz sand is nearly always pale gray to white or light yellowish-brown. Intermediate colors are associated with variable mixtures of clay-, silt-, and sand-sized ''host 11 material. (4) P2o5 determinations presented herein (Basic Data l) show definitely higher percentage values for zones containing lighter colored phosphate. Continuation, Phosphorite 50 From the foregoing a logical deduction is that the phosphate particles under- go successive stages of enrichment, and a color change from black to white occurs, reaching maximum development in the more permeable zones of coarse- grained quartz sand and pebbles. In these latter intervals chemical weath- ering and leaching processes are most easily effected. Conversely, clay- rich zones severely inhibit vertical and lateral movement of water. Hand-sorted samples of phosphate pebble material (+20 mesh) were collected by E. C. Pendery of Continental Oil Company from various drilling locations in South Georgia and North Florida. They were analyzed by J. B , Cathcart of the U. S. Geological Survey for both P2o5 and uranium content. Table 8 shows increases in percent P2 o 5 and U from black to white. Determi- nations by X-ray diffractometer on core samples from Echols and Clinch Counties show the phosphate mineral to be a carbonate fluorapatite as in the west-central Florida district (J. B~ Cathcart, written communication, The soft, dull, white phosphate particles near land surface are leached and contain wavellite and crandallite, according to Cathcart. These are the aluminum and calcium aluminum phosphate minerals, respectively. Altschuler and others (1964, p. 21) have summarized these mineralogic relationships in a diagrammatic cross-section. According to Altschuler and others (1958), the precise chemical formula for carbonate fluorapatite is uncertain but a provisional one is as follows: In th~ formula carbonate ions substitute for phosphate ions, and the excess fiuorine, according to the authors, serves to balance the charge difference when (co )-2 3 replaces (Po4 )-3. Continuation, Phosphorite 51 Table 8. P2o5 - U relationships to color of phosphate pebbles Color of phosphate pebble (+20 mesh) P205 content (percent) U content Ceercent ) Black Brown White Composite* 26.0 32-7 34.1 29 .1 o . oo6 0 .009 0 .009 0.009 *Composite of pebble from Lowndes, Echols and Clinch Counties, Georgia. Continuation, Phosphorite 52 In conclusion, the writer considers the use of color of phosphate particles as &n approximate field indication of quality and no more. Pale gray, light yellowish-brown or white matrix is probably an indication of potentially commercial material. A metallurgical laboratory analysis offers the best positive results. On the other hand, dark gray to black particles in a concentration greater than 10 to 15 percent by volume should not be ignored. 53 SUMMARY AND CONCLUSIONS Geologic and chemical data gained from drilling over 160 holes in Lowndes, Echols, Clinch and Charlton Counties showed presence of phosphorite in minable quantities about five miles west of Statenville (Echols County). Geologic information is of a reconnaissance nature only, being based upon drill holes spaced uniformly about a mile apart and drilled to depths of 75 and 90 feet. Chemical analyses were made on unwashed bulk samples from five-foot intervals, and in most cases consisted of a P2o5 determination only. Electric logs, plus some gamma-ray logs, provided an added tool for evaluating thickness and position of the phosphorite and associated lithol- The phosphorite within the project area is found in the Hawthorn Formation of middle Miocene age. The upper portion of the Hawthorn consists mostly of varicolored sandy clay; from preliminary data, montmorillonite is the dominant clay mineral in the upper portion. The lower portion, below 70 feet, has mostly limestone and dolomitic limestone, generally with abun- dant quartz grains, and also clay and sandy clay; preliminary determinations show the dominant clay minerals to be mixed layer montmorillonite-attapulgite and dolomite. The thickness of the Hawthorn ranges from about 100 feet in western Echols County to more than 275 feet in southeastern Clinch County. Distribution of the phosphorite appears to be primarily controlled by past structural activity in the South Georgia-North Florida area. The Withlacoochee Anticline and the Southeast Georgia Embayment are the dominant structural features. The positive features within the four-county area are quite likely a result of the Ocala uplift. Continuation, Summary and Conclusions Karst topography, with its characteristic sinkholes and lakes, is well developed southwest of the Georgia Southern and Florida Railway between Valdosta and Lake City, Florida (Plate I). Northeast of the railroad there is a sharp reduction in the number of sinkholes. In eastern Lowndes and western Echols Counties, however, the foregoing features are still present in the subsurface as solution cavities. Some abnormal thicknesses of phosphorite in this same area (Plate IV) are attributed to cavity fillings. Core holes which are offset a short distance from such drill holes would provide a check for possible sloughing of drill cuttings. The phosphorite thickens from about 20 to 40 feet in eastern Lowndes and western Echols Counties to more than 130 feet in southeastern Clinch County. Phosphate particles are associated with clear quartz sand in the former area and with bluish-green clay and sandy clay in the latter area. Pebble-sized (+20 mesh) phosphate is more common to the western portion of the study area, but yet amounted to only 5 to 10 percent by volume in the samples; 11pebble" is rare in the eastern portion. Concentrate (-20 +200 mesh) is the most common source of the phosphate in the project area. This material is of sand size, and is oviform. The slime fraction (-200 mesh) carries some P2o5 (Table 3), but preliminary tests indicate the amount is not significant. The volume of clay within the samples, also based on pre- liminary data and from Project Report No. 2 (Husted and others, 1966, pp. 25-29), shows an approximate range of 15 to 30 percent. Continuation, Summar,r and Conclusions 55 Future prospecting Results of this reconnaissance survey have produced some suggestions for future prospecting in South Georgia. They are as follows: (1) Take sufficient time to assemble and evaluate all published and open-file geologic information. This will include mainly subsurface data which are confined mainly to water wells and oil and gas tests. It also includes information from Fe~eral, State, and private construction projects. (2) For reconnaissance work a few advantages of drilling over coring are as follows: (a) Drilling can be as much as three times faster, thereby enabling the exploration crew to cover much more territor,r in a given allotted time. (b) Storage problems are reduced. (c) Exploration costs are reduced in terms of time, labor, and contract coring prices. (d) Comparison of P2o5 determinations between drill cuttings and cores in more than one hole indicates less than two percent deviation (Table 4). (3) Disadvantages of drilling are found where contamination from unconsolidated zones occurs; where clay minerals are washed out of the original sample; and where lithologic changes, unconformities, diastems and macrofauna are needed for correlation. The geologist on location should be alert to the possibilities of even minor caving or enlarging of less consolidated sections of the hole during drilling operations. Continuation, Summar,y and Conclusions Pump pressure should be kept as nearly constant as possible. Discharge should be sufficient only to get returns of larger particles within the sample in order to prevent excessive flushing action. (4) Electric and gamma-ray logs are useful additional data to supplement the sample logs. Portable units are available on a rental or contract basis from several companies. (5) Geologic structure is responsible in a somewhat broad sense for concentrating the South Georgia phosphorites. But in prospecting, one should understand that in the four-county project area, partic~arly the western part, localized concentration occurs in a modified sense. Examples of the latter are solution cavities and channels in the underlying limestone. 57 REFERENCES CITED Altschuler, Z. s., Cathcart, J. B., and Young, E. J., 1964, The geology and geochemistry of the Bone Valley Formation and its phosphate deposits, west-central Florida: Guidebook, Field Trip No. 6, Geol. Soc. America Annual Meeting, Miami Beach, November 1964. Altschuler, z. s., Clarke, R. S., Jr., and Young, E. J., 1958, Geochemistry of uranium in apatite and phosphorite: U. S. Geol. Survey Prof. Paper 314-D, pp. 45-90. Applin, P. L., and Applin, E. R., 1964, Logs of selected wells in the Coastal Plain of Georgia: Georgia Geol. Survey Bull. 74, 229 pp. Calver, J. L., and Vernon, R. 0., 1949, in Thoenen, J. R., and Warne, J.D., Titanium minerals in central and northeastern Florida: U. S. Bur. Mines Rept. Invest. 4515, p. 7. Cooke, C. W., 1925, in LaForge, Laurence, and others, Physical geography of Georgia: Georgia-Geol. Survey Bull. 42, p. 17. ------~---~-' 1939, in Stose, G. W., and others, Geologic map of Georgia: Georgia Geol. Survey and U. S. Geol. Survey. , 1944, Geologic map of the Coastal Plain of Georgia in Geology -------o~f~t~h-e-Coastal Plain of Georgia: U. S. Geol. Survey Bull. 94~ 121 pp. Dall, W. H., and Harris, G. D., 1892, Correlation papers, Neocene: U. S. Geol. Survey Bull. 84, 349 pp. Espenshade, G. H., and Spencer, C. W., 1963, Geology of phosphate deposits of northern peninsular Florida: U. S. Geol. Survey Bull. 1118, 115 pp. Herrick, S. M., 1961, Well logs of the Coastal Plain of Georgia: Georgia Geol. Survey Bull. 70, 462 pp. ------G=e--o-r.g,i-a-:--G, e1o9r6g5ia, A subsurface Geol. Survey study of Pleistocene Inf. Circ. 31, 8 pp. deposits in coastal Herrick, S. M., and Vorhis, R. C., 1963, Subsurface geology of the Georgia Coastal Plain: Georgia Geol. Survey Inf. Circ. 25, 80 pp. Howell, J. v., 1960, Glossary of geology and related sciences, second edition, Am. Geol. Institute, Washington, D. c., 325 pp. plus supple- ment. Husted, J. E., Furcron, A. S., and Bellinger, Frederick, 1966, South Georgia Minerals Program, Echols County: Georgia Geol. Survey Proj. Rept. No. 2, 79 pp. Continuation, References Cited 58 Kercher, Grace c., and others, 1966, Lexicon of geologic names of the United States for 1936-1960 (in three parts): U. S. Geol. Surv~ Bull. 1200, 4,341 pp. MacNeil, F. S., 1947, Geologic map of the Tertiary and Quaternary fomations of Georgia: U. S. Geol. Surv~ Oil and Gas Invest. Prelim. Map 72. ----~~~~-' 1950, Pleistocene shore lines in Florida and Georgia: U. S. Geol. Survey Prof. Paper 221-F, pp. 95-107. Mansfield, G. R., 1942, Phosphate resources of Florida: U. S. Geol. Surv~ Bull. 934, 82 pp. McCallie, S. W., 1896, Phosphates and marls of Georgia: Georgia Geol. Survey Bull. 5-A, 98 pp. McCallie, S. W., and others, 1908 (map), A preliminary geological map of Georgia: Georgia Geol. Survey. Meyer, F. W., 1962, Reconnaissance of the geology and ground-water resources of Columbia County, Florida: Florida Geol. Survey Rept. Inv. 30, 74 pp. Olsen, S. J., 1963, An upper Miocene fossil locality in North Florida: Florida Acad. Sci. Quart. Jour., v. 26, no. 4, pp. 308-314. Piombino, A. J., 1964, CW report --phosphates: Chemical Week, October 24, pp. 109-132. Pressler, E. D., 1947, Geology and occurrence of oil in Florida: Am. Assoc. Petroleum Geologists Bull., v. 31, no. 10, pp. 1851-1862. Puri, H. s., 1953, Contribution to the study of the Miocene of the Florida Panhandle: Florida Geol. Survey Bull. 36, 345 pp. Puri, H. s., and Vernon, R. 0., 1964 (revised), Summary of the geology of Florida and a ~debook to the classic exposures: Florida Geol. Survey Spec. Pub. No. 5, 312 pp. Shearer, H. K., 1917, Bauxite and fuller's earth of the Coastal Plain of Georgia: Georgia Geol. Survey Bull. 31, 340 pp. Spencer, J. W., 1891, General or preliminary geological report on southwest Georgia, in First report of progress, 1890-91: Geol. Survey of Georgia, pp. 57-6oland 82-86. Toulmin, L. D., 1952, Volume of Cenozoic sediments in Florida and Georgia: Geol. Soc. America Bull., v. 63, no. 12, pp. 1165-1176. ----~--~---' 1955, Cenozoic geology of southeastern Alabama, Florida, and Georgia: Am. Assoc. Petroleum Geologists Bull., v. 39, pp. 207-235 Vaughan, T. W., and others, 1914 (map), in Stephenson, L. W., and Veatch, J. 0., 1915, Underground waters of the Coastal Plain of Georgia: U.S. Geol. Survey Water-Supply Paper 341, p. 52. Continuation, References Cited 59 Veatch, J. 0., and stephenson, L. W., 1911, Preliminary report on the geology of the Coastal Plain of Georgia: Georgia Geol. Survey Bull. 26, 466 pp. Vernon, R. 0., 1951, Geology of Citrus and Levy Counties, Florida: Florida Geol. Survey Bull. 33, 256 pp. Yon, J. W., Jr., 1965, T.he stratigraphic significance of an upper Miocene fossil discovery in Jefferson County, Florida: Southeastern Geol., v. 6, no. 3, pp. 167-175. 60 BASIC DATA l. Summary of drilling and analytical data 2. Driller's logs BASIC DATA 1. Summary of' drilling and analytical data. [Altitude of' selected drill holes is given to the nearest :foot above mean sea level. ND i =not determined. ng and Research La Leader (-boratories, )W=inlsoond, aNtao.rthP2Coa5rodleintear,muinnaletisosnnsobteydSootuhtehrewrnisTee.]st- LOWNDES COUNTY Hole (Plate I) Altitude (:feet) Total depth (f'eet) Overburden (:feet) Phosphorite interval (:feet) P205 (percent) Remarks Ll --- 90 90 0 Electric log I2 -- - 75 45 45-72 ND Electric log L3 --- 75 40 40-73 ND Electric log L4 --- 90 55 55-60 4.6o Electric log 6o-65 4.25 65-70 4.30 70-75 4.30 75-80 5.92 L5 90 70 70-75 3.83 Electric log; white 75-80 4.93 phosphate particles 80-85 5.68 present 85-90 6.31 L6 180 180 0 Stratigraphic-structural test hole; electric log L7 75 75 0 Electric log 0'\ I-' BASIC DATA l (Continued) 0 g0 . Total Phosphorite 1::-s' Hole (Plate I) Altitude (f eet ) depth (feet) OVerburden (feet) interval (feet) P205 {_:pe rceil_t l Remarks -- - ~ c+ g1-' I8 --- 90 70 70-75 6.88 Electric log "' 75-80 80-85 7.80 5.92 ~ 85-90 5.l3 p, (I) Ol L9 --- 90 70 70-90 ND Electric log; minor 0 0 phosphate in interval ~ LlO l64 l42 35 35-60 ND Stratigraphic-struc- 60-65 6.50 tural test hole; 65-70 990 electric log; cross- 70-75 5.25 section 75-80 l.93 Lll l28 75 Ll2 --- 75 lO l0-l5 7.00 Electric log; cross l5-20 9.63 section 20-35 ND 40 40-50 ND Electric log; minor phosphate in interval Ll3 --- l55 l55 0 ---- Stratigraphic-struc- tural test hole; lost circulation at l55 feet; electric log Ll4 --- l35 l35 0 ---- Stratigraphic-struc- tural test hole; electric log R)' BASIC DATA l (Continued) 0 0 ~ Total Phosphorite 1-' ::::! Hole (Plate I) Altitude (f'eet) depth (f'eet) OVerbuxden (f'eet) interval (f'eet) P205 (per cent ) Remarks cfi5+ 1-' 0 ::::! Ll5 l58 75 35 35-40; ND Electric and gamma-ray "' Ll6 --- 75 45-65 logs; cross-section t""l ~ 30 30-45 ND Electric and gamma-ray p, (1) logs Ol Ll7 l59 75 0 0 35 35-70 ND Electric and gamma-ray logs; cross-section ~ c.::: Ll8 l65 75 35 35-70 ND Electric and gamma-ray logs; cross-section 0'\ l.A.l BASIC DATA l. Sunnnary of drilling and ana~ical data. [Altitude of selected drill holes is given to the nearest foot above mean sea level. ND = not determined. Leader(--) = no data. P205 determinations by Southern Test- ing and Research Laboratories, Wilson, North Carolina, unless noted otherwise.] ECHOlS COUNTY Hole (Plate I) Altitude (feet) Total depth (feet) Overburden (feet) Phosphorite interval (feet) P205 (:percent) Remarks El l24 280 30 30-l75 ND Strati~raphic-struc tural test hole; cored interval = 6o-63 feet; no logs E2 --- 225 25 25-30 L88 Stratigraphic-struc- 30-35 6.42 tural test hole; hole 35-40 5.62 caved; no logs 40-45 537 45-50 5.68 50-55 5-57 55-6o 5-75 6o-65 ND 65-70 4.00 70-75 2.63 75-80 3-72 80-85 4.25 85-90 3.83 90-95 9-90 95-lOO 2.88 l00-l05 3-92 l05-ll0 5.l8 ll0-ll5 3.83 ll5-ll8 3.04 ~ BASIC DATA 1 (Continued) 0 0 8- Hole Tot a l Altitude depth Phosphorite OVerburden interval P205 I-' ~ (Plate I) E3 (f'~e"li_ --- (f'eet_l 105 (f'eet) 30 (f'eet) 30-105 {percent) ND Remarks Gamma-ray log c+ gI-' ... l:z:.1 E4 --- 90 () 35 35-70 ND Cored interval = 40-44 f'eet; no logs ::r' .0..... 00 E5 --- 90 30 30-90 ND Electric log 0 0 ~ E6 --- 200 60 6o-125 ND Electric log : E7 --- 90 25 25-80 ND Electric log E8 158* 90 62 62-75 ND Electric log E9 158* 90 40 40-88 ND Electric log ElO 158* 90 Ell --- 90 El2 --- 90 55 55-90 ND Electric log 55 55-90 ND Electric log 6o 6o-90 ND Electric log El3 --- 90 50 50-90 ND Electric log El4 169 72 40 40-90 ND Cored interval = 70-72 f'eet; electric log El5 170 90 25 25-30 0.45 Cored interval = 45-49 30-35 1.13 f'eet; electric log 35-40 2.25 40-45 2.43 45-50 1.91 0\ \Jl BASIC DATA l (Continued) (') 0 ~ Total Phosphorite I::-s' Hole Altitude (Plate I) (feet) depth (feet) Overburden _(feet_)_ interval P205 _ (f~et)_ i:eercent) Remarks ~ I-' 0::s El5 170 90 25 50-55 2.77 "' (Cont.) 55-6o 2.30 ln".. 6o-65 2.38 P" 0 65-70 2.06 1-' Ol 70-75 1.88 (') 75-90 ND 0 ~ El6 157 6o 60 0 ---- Hole caved; no logs 0:.::: El7 147 90 25 25-50 ND Electric log El8 147 8o 25 25-30 0.97 Electric log 30-35 1.91 35-40 2.06 40-45 3.30 45-50 2.77 50-55 2.67 55-60 2.35 60-65 2.35 65-70 2.67 70-75 3.14 75-77 ND El9 16o 100 40 40-45 0.33 Electric log 45-50 0.78 50-55 0.33 55-6o 0 . 29 6o-65 0.88 65-70 0.78 70-100 ND ~ ~ BASIC DATA 1 (Continued) 0 0 8- 1-' Total Phosphorite Hole Altitude depth Overburden interval P205 ! (Plate I) (feet) ~feet) (feet) (feet) ~percent) Remarks 1-' ...0:.:s E20 --- 90 35 35-75; ND Electric log t<.J 85-90 r.l P' 0 E21 141 75 20 20-25 0.22 Electric log I-' til 25-30 0.25 0 0 30-35 0.45 35-40 0.70 ~ ~ 40-45 1.47 45-50 1.63 50-55 1.29 55-6o 1.93 E22 127 6o 20 20-25 0.70 Cored interval = 20-22, 25-30 1.38 30-32 feet; no logs 30-35 0.75 35-40 0.80 40-45 1.00 45-50 1.38 50-55 0.84 55-6o 0.80 F23 152 75 45 45-50 2.25 No logs; cross-section 50-55 6.00 55-6o 6.25 6o-70 ND E24 151 90 15 15-60 ND Electric log; cross- 60-65 3.09 section 65-70 5.75 70-75 10.13 75-80 7.25 0'\ ~ BASIC DATA l (Continued) 0 0 8- Total Phosphorite 1-' :::J Hole (Plate I) Altitude (feet) depth (feet ) Overburden _ (f~etl_ interval _(_feet) P205 (:Qercent) Remarks ~ 1-' 0 E25 --- 55 50 50-55 ND No logs ..:.::J 1n:.>;1 E26 165 90 45 45-80 ND Cored,interval = 55-6o P" 0 feet; electric log; I-' Ol E27 --- 55 cross-section 0 0 25 25-30 30-35 0.63 Cored interval = 30-35 0.75 feet; electric log ~ 35-40 2.95 40-45 3.46 45-50 3-75 E28 170* 105 61 61-65 5.87 Electric log 65-70 3.72 70-75 2.56 75-80 7.6o 80-85 8.00 85-90 10.75 E29 --- 90 6o 6o-90 ND Cored interval = 6o-61 feet; electric log E30 170* 90 45 45-60; ND Electric log 88-90 E31 170* 90 36 36-45; ND Electric log 60-77; 85-90 E32 --- 105 40 40-105 ND Electric log 8j BASIC DATA l (Continued) 0 0 8- Total Phosphorite 1::-s' Hole (Plate I) Altitude (feet) depth (feet) Overburden (feet) interval (feet) P205 (percent) Remarks ~ ..... :0:s E33 --- lOO 30 30-92 ND Electric log "' E34 --- 90 1n?=:1 45 45-50 2.35 Cored interval = 45-50 P" 0 50-55 3.62 feet; electric log 1-' Ol 55-6o 2.09 0 6o-65 65-70 70-75 4.00 3.92 9.l5 0 [ "-G 75-80 7.6o 80-85 4.06 E35 l65 90 E36 l65 90 48 48-50 ND Electric log; cross- 50-55 8.25 section 55-6o 6.50 6o-65 8.63 65-70 l0.60 70-90 ND 40 40-90 ND Cored interval = 45-47 feet; electric log; cross-section E37 l70 90 20 20-30 ND Electric log; cross- 30-35 2.20 section 35-40 4.25 40-45 2.88 45-50 3.42 50-80 ND 80-86 7.88 0'\ \.() BASIC DATA l (Continued) 0 g0 . Total Phosphorite 1::-s' Hole Altitude depth Overburden interval P205 ~ (Plate I) (f'eet}_ (_feet) _(f'~ejJ_- _ _{f'eet) (percent) Remarks --- ---- c+ 1-'- :0:s E38 --- 90 35 35-40 ND Electric log; cross- '" 40-45 l.l5 section lnzj 45-50 2.06 P" 0 50-55 2.77 I-' Ul 55-57 57-82 3.67 ---- 82-90 ND 0 0 ~ " 1-' BASIC DATA 1 (Continued) 0 0 8- Total Phosphorite f-Jo ~ Hole Altitude depth OVerburden interval P205 ~ (Plate I) (feet) (f eet) (feet) (feet) (-percent) Remarks f-Jo 0 ...~. CL3l 127* 90 40 40-45 2.30 Gamma-ray log 0 45-50 2.25 I-' 1-' 50-90 ND ~ () P" CL32 --- 90 45 45-90 ND Cored interval = 60-65 0 0 feet; minor phosphate ~ CL33 128* 90 34 34-44 ND Gamma-ray log "<: CL34 113 90 40 40-90 ND Cored interval = 45-50 feet; gamma-ray log CL35 125 90 CL36 --- 90 CL37 114 90 55 55-90 ND Gamma-ray log 30 30-90 ND Cored interval = 45-48 feet; gamma-ray log 40 40-90 ND Cored interval = 55-6o feet; gamma-ray log CL38 154* 90 70 70-90 ND Cored interval = 40-45 feet; caved hole at 25 feet; no logs CL39 --- 90 70 70-90 ND Electric log crJ+o --- 90 CrJ+l --- 90 90 0 ---- Electric log 75 75-90 ND Electric log CP 1\) BASIC DATA l (Continued) 0 0 ~ ...... Hole (Plate I) Altitude (feet) Total depth (feet) OVerburden (feet) Phosphorite interval (feet) P205 (:percent) Rema~rks ~ t+ ...... 0 ::::s CVl-2 --- 75 75 0 ---- Electric log "' 0 1--' CW3 --- 90 70 70-90 ND Electric log; minor 1-' ::::s () :phosphate l:S' 0 c:U+4 - -- 75 75 0 ---- Electric log 0 ~ CW5 --- 75 75 0 ---- Electric log ~ c:U+6 --- 75 6o 6o-70 ND Electric log; minor :phosphate CVl-7 --- 90 c:U+8 --- 90 75 75-90 ND Electric log 6o 60-90 ND Electric log CW9 --- 75 CL50 --- 90 75 0 --- - Electric log 70 70-90 ND Electric log CL5l -- - 90 6o 60-90 ND Electric log CL52 --- 75 70 70-75 ND Electric log; minor :phosphate CL53 --- 75 75 0 --- - Electric log *Scaled f'rom Georgia Southern and Florida Railway :profile, Valdosta to Fargo; and f'rom U.S. Coast (X) and Geodetic Survey Line 2. w BASIC DATA 1. Summary of dri\lling and analytical data. [Altitude of selected drill holes is given to the nearest foot above mean sea level. ND = not determined. Leader ( --) = no data. P205 determinations by Southern Test- ing and Research Laboratories, Wilson, North Carolina, unless noted otherwise.] CHARLTON COUNTY Hole (Plate I) CHl CH2 CH3 CH4 CH5 CH6 CH7 CH8 CH9 CHlO Altitude (feet) 170* 16o* ll9* 125* 120* 118* 120* 152* 130* 145* Total depth (feet) 75 75 90 75 75 75 75 75 75 75 Overburden (feet) 75 75 80 Phosphorite interval (feet) 0 0 80-90 75 0 65 65-75 75 0 75 0 75 0 75 0 75 0 P205 (percent) ------- ND ---- ND -- ----------- ---- Remarks Electric log Electric log Electric log; minor phosphate Electric log Electric log; minor phosphate Electric log Electric log Electric log Electric log Electric log +CP BASIC DATA 1 (Continued) 0 0 8- Total Phosphorite 1::-s' Hole (Plate I) CHll Altitude (feet) 95* depth (feet) 75 Overburden _(f'eet) 75 interval (f'eet) 0 P205 (percent) ---- Remarks Electric log ~ g1-' ... 0 CH12 135* 75 75 0 ---- Electric log ~ li ~ g 0 0 ~ *Estimated f'rom Maniac quadrangle (USGS 1:62,500; contour interval 10 f'eet). ()) \Jl BASIC DATA l. Summary of' drilling and analytical data. [Altitude of' selected drill holes is given to the nearest f'oot above mean sea level. ND =not determined. Leader (--) =no data. P205 determinations by Southern Test- ing and Research Laboratories, Wilson, North Carolina, unless noted otherwise.] Hole (Plate I) LAl Altitude (f'eet) Total depth (f'eet) l77 LANIER COUNTY Overburden (f'eet) 38 Phosphorite interval (f'eet) 38-45 P205 (percent) ND Remarks Stratigraphic-structural test hole; lost circulation at 177 f'eet; electric log ()) 0'\ BASIC DATA 2. Driller's logs. [All depths in feet. Symbols (Ll) indicate hole numbers.] LOWNDES COUNTY Ll 0-60 Sandj sandy clay 60-72 Clay, white 72-85 Clay, blue, softj fossils 85-90 Clay, hard NO PHOSPHORITE L2 0-25 Sandj sandy clay 25-40 Clay 40-41 Chert 41-75 Clayj chert layers PHOSPHORITE 45-72 L3 0-15 Clay, sandy 15-38 Clay, white 38-73 Clay, blue 73-75 Chertj clayj limestone PHOSPHORITE 40-73 0-5 5-25 25-75 75-80 80-90 Sand Clay, sandy Clay Clayj chert layers Clay PHOSPHORITE 55-80 L5 0-20 Sandj sandy clay 20-45 Clay 45-90 Sand; sandy clay PHOSPHORITE 70-90 L6 0-30 30-40 40-50 50-82 82-92 92-94 94-102 102-180 Sandj sandy clay Clay, white Sandj sandy clay Clay, sandy Clay, blue, hard Chert Clay Clayj limestone layers NO PHOSPHORITE L7 0-20 Sandj sandy clay 20-32 Clay 32-60 Sandj clay, white, soft 60-75 Clay NO PHOSPHORITE L8 0-8 8-20 20-40 40-70 70-90 Clay, sandy Clay, white Sandj clay, white, soft Clay Clay, blue, sandy PHOSPHORITE 70-90 L9 0-5 Sand 5-55 Clay, sandy 55-90 Clay PHOSPHORITE 70-90 Continuation, Lowndes County 88 BASIC DATA 2 (Continued) LlO* 0-5 5-20 20-25 25-30 30-35 35-40 50-60 60-70 70-80 80-95 95-105 105-125 125-130 130-135 135-142 Sand, fine- to coarse-grained, arkosic Clay, pale brownish-gray, very sandy Sand, fine- to coarse-grained; some clay as above As above; some clay, pale yellowish-brown, sandy Sand; clay, mottled, very sandy; some argillaceous, limonitic sand Clay, dark brownish-green, blocky, becoming pale green at depth Clay, pale green to white, blocky, cherty Sand as above Clay as above Sandstone, pale yellowish-green, fine-grained, interbedded with clays; some limestone As above but becoming dolomitic Clay, pale green, sandy; minor amount fine-grained sandstone and white to pale green sandy limestone Clay, pale bluish-green, blocky Clay as above; some chert Limestone, dolomitic, sandy PHOSPHORITE 35-80 Lll* 0-10 10-20 20-30 30-55 55-75 Sand, clayey Sand Limestone, very sandy and clayey Claystone, pale bluish-gray, very sandy, friable; influx limestone, yellowish-brown, dolomitic, sucrosic, pitted, hard; minor amount pale yellow crystalline limestone Claystone, pale greenish-gray, siliceous, very sandy; minor amount pale yellow limestone as above PHOSPHORITE 10-35 Ll2 0-40 Sand; sandy clay 40-50 Clay, sandy 50-75 Clay PHOSPHORITE 40-50 Continuation, Lowndes County 89 BASIC DATA 2 (Continued) Ll3 0-5 5-80 80-100 100-104 104-112 112-120 120-155 Sand Clay, white, yellow Clay, light blue; rock layers Chert Clay; rock layers Rock Clay; rock layers (LOST CIRCULATION in limestone cavity at 155) NO PHOSPHORITE Ll4 0-4 4-72 72-80 80-95 95-100 100-128 128-135 Sand Clay, sandy Rock, brown; clay layers Clay Limestone Clay, white; limestone, soft Limestone, brown NO PHOSPHORITE Ll5* 0-5 5-15 15-25 25-35 35-50 50-65 65-75 Sand, quartz, pale gray, coarse-grained Claystone, mottled reddish-brown, yellowish-brown and gray, very sandy Claystone, medium brown and pale gray; sandstone, quartz, pale gray, clayey Sand as above; minor claystone as above Sand as above Claystone, bluish-gray with black specks, sandy; sharp decrease in phosphorite Sand, quartz, very pale greenish-gray, calcareous, very clayey, with soft limy nodules; minor claystone as above PHOSPHORITE 35-40; 45-65 Ll6 0-4 4-30 30-45 45-49 49-75 Sand Clay, sandy Sand Rock Clay PHOSPHORITE 30-45 Continuation, Lowndes County 90 BASIC DATA 2 (Continued) IJ.7* 0-20 20-25 25-35 35-50 50-65 65-75 Sand, quartz, varicolored, clayey; minor claystone Claystone, medium brown; sandstone as above Sand, quartz, light gray, conglomeratic, arkosic Sand, quartz, pale yellowish-brown, clayey Sand as above; claystone, medium brown; minor amount limestone, pale yellowish-brown, dolomitic, with clear quartz grains Sand as above, very clayey; sharp decrease in phosphorite 65-70 PHOSPHORITE 35-70 Ll8* 0-5 5-10 10-15 15-25 25-30 30-70 70-75 Sand, fine- to medium-grained, arkosic Clay, dark brown, very sandy Clay, light brownish-green to dark brown, blocky, sandy, lignitic Sand; minor amount clay as above Clay, dark brownish-green, blocky, sandy Sand; minor amount clay as above Clay, dark green, blocky, sandy PHOSPHORITE 35-70 *Cross-section. Samples checked and some descriptions modified by the writer. 91 BASIC DATA 2. Driller's logs. [All depths in feet. Symbols (El) indicate hole numbers.] ECHOLS COUNTY El* 0-25 25-30 30-40 4o-6o 60-75 75-95 95-115 115-130 130-185 185-225 225-235 235-255 255-280 Claystone, varicolored, sandy Claystone, grayish-green, sandy Claystone, slightly calcareous Sandstone, ~uartz, slightly calcareous Sandstone, quartz; claystone, grayish-green Sandstone, quartz; minor limestone Claystone, grayish-green Sandstone, ~uartz; claystone, grayish-green; trace limestone Limestone, pale yellowish-brown, sandy; minor quartz sand grains Limestone; shale, pale green, siliceous; trace of chert Limestone, white and pale yellowish-brown, calcite grains; claystone, pale yellowish-green, "fuller's earth 11 type Limestone Limestone as above; trace limestone, light gray with black specks, sandy CORE 60-63 PHOSPHORITE 30-175 E2 (RERUN) 0-30 30-50 50-75 75-108 108-112 112-118 118-125 125-141 141-148 148-155 155-175 175-180 180-225 Sand Clay, hard Clay; limestone layers Clay; limestone layers Rock Limestone, soft Rock Clay Limestone, white Clay Clay; limestone layers Limestone, sandy Clay; limestone layers PHOSPHORITE 25-118 Continuation, Echols County 92 BASIC DATA 2 (Continued) E3 0-5 5-15 15-40 40-70 70-74 74-105 Sand Clay Clay, white Clay Limestone Clay; limestone layers PHOSPHORITE 30-105 E4 0-5 5-20 20-55 55-70 70-90 Sand Clay, sandy Clay Clay, blue Clay; limestone layers CORE 4o-44 PHOSPHORITE 35-70 E5 0-30 30-40 40-45 45-55 55-70 70-71 71-75 75-85 85-90 Sand Clay, sandy Clay Sand Clay, dark blue Limestone Clay Sand Clay; minor limestone PHOSPHORITE 30-90 E6 0-8 8-15 15-40 4o-44 44-60 60-70 70-90 90-92 92-125 125-140 Clay Sand Clay, yellow Clay, gray Clay, blue Sand Clay, blue, sandy Limestone Clay Limestone, sandy; interbedded clay E6 (Continued) 140-195 Clay; limestone layers 195-200 Limestone, brown PHOSPHORITE 60-125 E7 0-10 10-18 18-30 30-55 55-70 70-80 80-88 88-90 Clay, sandy Sand Clay, white Clay, blue Clay Clay, sandy Clay Limestone PHOSPHORITE 25-80 E8 0-4 4-10 10-25 25-45 45-50 50-62 62-75 75-88 88-90 Sand Clay Sand Clay, white Sand Clay, white Clay Clay, hard; limestone layers Clay; chert layers PHOSPHORITE 62-75 E9 0-5 5-12 12-25 25-40 40-45 45-70 70-88 88-90 Sand Clay, sandy Clay, yellow and white Clay, blue Clay, sandy Clay Clay, gray Clay PHOSPHORITE 40-88 Continuation, Echols County 93 BASIC DATA 2 (Continued) ElO 0-8 8-30 30-50 50-65 65-68 68-74 74-76 76-90 Clay, yellow and white, sandy Clay, blue, sandy Clay, blue Clay, white and brown Rock Clay Rock layers Clay, rock layers PHOSPHORITE 55-90 Ell 0-6 Clay, sandy 6-20 Sand 20-55 Clay, sandy 55-90 Clay PHOSPHORITE 55-90 El2 0-15 15-20 20-50 50-60 60-90 Clay, sandy Sand Clay, sandy Clay Clay, gray MINOR PHOSPHORITE 60-90 El3 0-12 12-16 16-20 20-25 25-42 42-46 46-47 47-50 50-90 Clay, sandy Sand Clay, red and white Clay, white Clay, light green Clay, white Rock layers Clay, light green Clay MINOR PHOSPHORITE 50-90 El4 0-5 5-10 10-20 20-40 40-90 Sand Clay, sandy Sand Clay, sandy Clay CORE 70-72 PHOSPHORITE 40-90 El5 0-15 15-25 25-46 46-60 6o-70 70-80 80-90 Sand Clay, sandy Clay, sandy Sand Clay, sandy Sand Clay, sandy CORE 45-49 PHOSPHORITE 25-90 El6 0-5 5-10 10-16 16-18 18-60 Sand Clay, sandy Sand Clay Sand HOLE CAVED NO PHOSPHORITE El7 0-20 20-50 50-72 72-74 74-90 Sand Sand Clay, sandy Limestone Clay; limestone layers PHOSPHORITE 25-50 Continuation, Echols County BASIC DATA 2 (Continued) El8 0-45 Sand 45-60 Clay, blue 60-77 Sand 77-80 Limestone PHOSPHORITE 25-77 El9 0-5 5-12 12-15 15-30 30-40 40-75 75-100 Sand Clay Sand Clay, white Sand Sand Clay; limestone at 100 feet PHOSPHORITE 40-75 E20 0-5 5-12 12-20 20-35 35-55 55-75 75-85 85-90 Sand Clay Sand Clay, white, soft Clay, blue Clay, gray Clay, blue Sand PHOSPHORITE 35-75; 85-90 E21 0-5 Sand 5-13 Clay 13-60 Sand 60-72 Clay 72-75 Rock PHOSPHORITE 20-6o 0-40 Sand 40-60 Sand; clay layers; sandstone at 6o feet CORE 30-32 PHOSPHORITE 20-60 E23** 0-28 28-45 45-58 58-70 70-75 Sand Clay Sand Clay Limestone PHOSPHORITE 45-70 0-5 5-15 15-20 20-60 60-80 80-90 Sand, arkosic Sand; minor amount mottled clay Clay, brown, sandy Clay, greenish-gray with brown streaks Clay, sandy, soft Clay; rock layers PHOSPHORITE 30-80 0-20 Sand 20-50 Clay, sandy 50-55 Sandstone MINOR PHOSPHORITE 50-55 0-15 15-20 20-45 45-65 Sand, fine- to coarsegrained, arkosic Clay, mottled, sandy Sand; some clay as above Clay, dark brown, sandy Continuation, Echols County 95 BASIC DATA 2 (Continued) E26**(Continued) 65-80 Clay, white 80-81 Chert layer 81-90 Clay; limestone layer CORE 55-60 PHOSPHORITE 45-80 E27 0-15 15-30 30-40 40-45 45-48 48-53 53-55 Clay Sand Clay, sandy, soft Clay, hard Chert Clay, rock layers Chert CORE 30-35 PHOSPHORITE 25-50 E28 0-16 16-18 18-25 25-40 40-60 60-61 61-68 68-70 70-73 73-76 76-91 91-105 Clay Sand Clay Sand Clay, blue Chert Sand Chert Clay Chert Clay, sandy Clay PHOSPHORITE 61-91 E29 0-5 5-13 13-25 25-40 40-60 60-90 Sand Clay Sand Clay, sandy Clay, blue Clay, gray; rock layers CORE 60-61 PHOSPHORITE 60-90 E30 0-45 45-6o 60-78 78-82 82-88 88-90 Sand; sandy clay Clay, sandy Clay, blue Chert Clay Clay, sandy MINOR PHOSPHORITE 45-60; 88-90 E31 0-12 12-15 15-17 17-30 30-36 36-45 45-60 60-77 77-82 82-85 85-90 Clay, sandy Sand Clay Sand Clay, white Clay, gray Clay, blue Clay, gray Clay, blue Chert Clay; chert layers PHOSPHORITE 36-45; 60-77; 85-90 E32 0-5 5-10 10-25 25-30 30-40 40-76 76-78 78-100 100-105 Sand Clay Sand Clay Sand; sandy clay Clay, blue Chert Clay, green Chert layers; clay PBOSPHORITE 40-105 E33 0-5 5-15 15-30 30-35 35-60 Sand Clay Sand; clay Clay Clay, blue Continuation, Echols County BASIC DATA 2 (Continued) E33 (Continued) 60-75 Clay 75-92 Clay, sandy 92-100 Clay; limestone layers PHOSPHORITE 30-92 E34 0-5 5-12 12-45 45-50 50-55 55-60 60-85 85-90 Sand Clay Sand; sandy clay Clay Sand Clay, hard Clay, sandy Limestone; chert PHOSPHORITE 45-85 E35** 0-48 Sand; sandy clay 48-70 Clay, blue, sandy 70-90 Clay; limestone layers PHOSPHORITE 48-70 0-5 5-30 30-70 70-90 Sand, fine- to coarsegrained, arkosic Clay, mottled, very sandy As above, with brown clay at top Clay, sandy; chert and limestone layers CORE 45-47 PHOSPHORITE 40-90 E37** 0-10 10-20 20-30 Sand, fine- to coarsegrained Sand as above; clay, pale green, blocky, sandy Clay, dark brown, blocky, sandy E37** (Continued) 30-50 50-71 71-80 80-86 86-90 Sand Clay, sandy Clay, blue Sand Clay; limestone PHOSPHORITE 20-71; 80-86 0-5 5-35 35-40 40-45 45-57 57-90 Sand Sand; minor amount mottled clay Sand as above; minor amount pale brown to gray clay Clay, blue Sand Clay PHOSPHORITE 35-57; 82-90 E39 0-5 5-20 20-35 35-60 60-70 70-124 124-128 128-132 132-144 144-146 Sand Clay Sand Clay, blue Clay, light blue Clay; limestone layers Limestone, sandy Limestone, white, soft Limestone, soft and hard Limestone, brown, hard PHOSPHORITE 35-6o E4o 0-5 5-20 20-55 55-75 Sand Clay Sand; sandy clay Clay; chert; limestone layers PHOSPHORITE 20-55 Continuation, Echols County 97 BASIC DATA 2 (Continued) E4l 0-35 Sand 35-40 Clay 40-90 Clay; rock layers PHOSPHORITE l0-90 E42** 0-5 5-20 20-45 45-56 56-7l 7l-75 Sand Clay, sandy Sand Clay, blue, sandy Limestone, sandy; clay layers Clay PHOSPHORITE 45-56 E43 0-4 4-l5 l5-55 55-60 6o-80 80-90 Sand Clay Sand Clay, sandy Sand Clay; limestone PHOSPHORITE 50-80 E44 0-4 4-l5 l5-50 50-57 57-59 59-65 65-84 84-lOO l00-ll6 ll6-ll8 Sand Clay Sand Clay, blue, sandy Clay, hard Clay; limestone layers Clay, blue Clay Limestone, white (Cavity) LOST CIRCULATION PHOSPHORITE 50-57; 84-lOO E45** 0-20 20-30 30-65 65-80 80-95 95-l02 l02-l05 Sand, fine- to coarsegrained, arkosic Clay, sandy Sand Clay Clay, hard Clay, soft Limestone, white PHOSPHORITE 25-65; 95-l02 E46** 0-5 5-20 20-25 25-50 50-63 63-70 70-80 80-85 85-88 88-90 Sand, arkosic Sand, arkosic; minor . amount mottled clay As above, with pale to dark brownish-green blocky clay Clay, sandy Sand Clay; limestone layers Clay Clay Limestone Clay PHOSPHORITE 25-80 E47** 0-5 5-lO l0-25 25-50 50-60 60-70 70-90 Sand Sand; minor amount mottled clay Clay, dark brownishgreen, sandy Sand Clay Clay; sand layers Clay; limestone layers PHOSPHORITE 20-50; 60-70 Continuation, Echols County BASIC DATA 2 (Continued) E48** 0-4 4-15 15-57 57-65 65-75 75-90 Sand Clay Sand Clay Clay; sand layers Clay PHOSPHORITE 15-57; 65-75 E49** 0-5 5-17 17-68 68-90 Sand; sandy clay, reddish brown Clay Sand Clay, sandy; limestone layers PHOSPHORITE 25-80 E50** 0-10 10-16 16-62 62-80 80-90 Sand Clay Sand Clay; limestone layers Clay PHOSPHORITE 45-65 E5l 0-6 6-14 14-22 22-30 30-68 68-75 Sand Clay Sand Clay Clay, sandy Clay PHOSPHORITE 30-68 E52 0-4 Sand 4-14 Clay 14-17 Sand 17-28 Clay E52 (Continued) 28-45 Clay, sandy 45-85 Clay, blue, sandy 85-90 Clay PHOSPHORITE 65-85 E53 0-5 5-20 20-70 70-75 75-85 85-90 Sand Clay Clay, sandy Clay Clay, sandy Clay PHOSPHORITE 55-70; 75-85 0-10 10-28 28-55 55-65 65-75 Sand, fine- to coarsegrained, arkosic Clay, mottled Sand; clay, sandy Clay Clay; limestone layers PHOSPHORITE 25-75 E55 0-5 Sand 5-20 Clay 20-75 Clay, sandy PHOSPHORITE 40-75 0-5 5-25 25-35 35-40 40-45 45-50 50-70 70-75 75-80 80-90 Clay Sand Clay, sandy Clay Clay; limestone layers Sand Clay Sand Clay, blue Clay, sandy PHOSPHORITE 35-50; 70-75; 80-90 Continuation, Echols County 99 BASIC DATA 2 (Continued) E57 0-5 Sand 5-15 Clay 15-45 Sand; clay, sandy HOLE CAVED PHOSPHORITE 25-45 E58 0-5 5-20 20-40 40-44 44-75 Sand Clay Clay, blue Rock Clay; rock layers PHOSPHORITE 30-40 E59 0-10 10-16 16-65 65-73 73-75 Sand Rock Clay; rock layers Limestone Limestone, soft LOST CIRCULATION NO PHOSPHORITE E60 0-16 16-25 25-30 30-35 35-75 Sand Clay Clay, sandy Limestone Clay; limestone layers PHOSPHORITE 25-30 E6l 0-4 4-14 14-25 25-40 40-50 50-90 Sand Clay Sand; clay Clay, blue, sandy Sand; clay, sandy Clay PHOSPHORITE 40-50 E62 0-4 4-14 14-25 25-32 32-35 35-45 45-50 50-55 55-62 62-90 Sand Clay Clay, white, sandy Clay, white Clay, blue Sand Clay, blue Clay, gray, hard Sand Clay; rock layers PHOSPHORITE 35-45; 55-62 0-3 3-30 30-36 36-42 42-47 47-60 60-75 Sand Clay Sand Clay Clay, sandy Clay, white Clay, blue CORE 45-50 PHOSPHORITE 42-47 E64 0-4 4-17 17-35 35-40 40-44 44-47 47-75 Sand Clay Sand Sand; rock layers Clay, blue Limestone Clay; limestone layers PHOSPHORITE 17-35 0-3 3-28 28-35 35-55 55-66 66-75 Sand Clay, sandy Clay, blue, sandy Clay, sandy Clay, sandy Clay, hard PHOSPHORITE 35-55 Continuation, Echols County 100 BASIC DATA 2 (Continued) E66 0-3 3-32 32-38 38-45 45-70 70-75 Sand Sand; sandy clay Clay Clay, sandy Clay; rock layers Clay, blue PHOSPHORITE 38-45 0-3 3-14 14-30 30-40 40-57 57-60 60-75 Sand Clay Sand Clay, blue, sandy Clay, green Limestone Clay PHOSPHORITE 40-57 E68 0-3 3-10 10-29 29-52 52-60 60-75 Sand Clay Sand Clay, blue, sandy Limestone, sandy Clay; limestone layers PHOSPHORITE 35-52 0-4 4-30 30-40 40-55 55-75 Sand Clay Sand Clay, sandy Clay; limestone layers PHOSPHORITE 40-55 E70 0-2 Sand 2-12 Clay 12-20 Sand E70 (Continued) 20-25 25-30 30-35 35-55 55-65 65-75 Clay, blue, sandy Sand Clay Clay; rock layers Rock Clay; rock layers CORE 30-32 PHOSPHORITE 20-55 E71 0-4 4-12 12-20 20-25 25-32 32-42 42-55 55-75 Sand Clay Sand Clay Clay, blue, sandy Clay, white and brown Limestone Clay; limestone layers PHOSPHORITE 20-42 0-3 3-18 18-35 35-58 58-65 65-67 67-75 Sand Clay Clay, sandy Sand; rock layers Clay; rock layers Rock Clay CORE 15-25 PHOSPHORITE 18-58 E73 0-3 3-12 12-46 46-52 52-55 55-70 70-71 Sand Clay Sand Clay, sandy Clay Rock (Cavity) LOST CIRCULATION PHOSPHORITE 46-70 Continuation, Echols County 101 BASIC DATA 2 (Continued) 0-28 28-50 50-56 56-62 Sand; sandy clay Clay, blue, sandy Limestone (Cavity) LOST CIRCULATION PHOSPHORITE 28-50 E75 0-38 38-50 50-58 58-66 66-72 72-85 85-100 100-120 120-127 127-135 135-144 144-148 148-160 Sand Sand; rock layers Clay Clay; limestone layers Limestone Limestone, white, soft Clay, blue; limestone layers Clay, blue; minor limestone Clay; limestone layers Limestone, sandy; clay Limestone, sandy Clay Limestone, hard and soft PHOSPHORITE 20-58 E77 0-5 5-18 18-25 25-41 41-45 45-65 65-80 Sand Clay Sand Sand; clay, blue Clay Sand Limestone PHOSPHORITE 18-25; 45-80 0-16 16-20 20-35 35-48 48-53 53-75 Sand Clay, blue Clay; limestone layers Clay Clay; limestone layers Limestone; minor clay PHOSPHORITE 20-35 *Samples checked and some descriptions modified by the writer. **Cross-section. Samples checked and some descriptions modified by the writer. 102 BASIC DATA 2. Driller's logs. [All depths in feet. Symbols (CLl) indicate hole numbers.] CLINCH COUNTY CLl* 0-15 15-45 45-50 50-55 55-70 70-80 80-90 90-95 Sandstone, quartz, mottled brown, red, yellow and gray, coarsegrained, clayey No samples Sandstone, quartz, pale yellowish-brown, very coarse-grained, very friable, scattered feldspar grains Sandstone, quartz, pale yellowish-gray, fine-grained, very friable; black fine-grained particles displaying metallic luster (heavy minerals?) Sandstone as at 45 feet; black fine-grained particles as above Claystone, pale greenish-gray, silty; sandstone, quartz, coarsegrained, clayey, very friable Sandstone as above; minor amount claystone as above and limestone, pale yellow Sandstone, quartz, medium gray, fine-grained; minor amount inter- bedded claystone as at 70 feet CORE 45-55; 90-95 PHOSPHORITE 75-95 (Minor phosphorite 75-85) C~* 0-20 20-30 30-43 43-55 55-65 65-75 75-100 100-115 115-125 125-145 145-170 Sandstone, quartz, mottled brown, red, yellow, gray, very clayey, quartz grains very coarse-grained, becoming conglomeratic at 15 feet Sandstone, quartz, mottled pale yellowish-brown and gray; less clayey feldspar fragments common Sandstone as in uppermost unit Claystone, medium gray, silty; sandstone, quartz, pale yellowishbrown, clayey Sandstone, quartz, pale yellowish-brown, friable; shale, pale greenish-gray, mottled with black specks, siliceous Sandstone as above. Limestone, pale yellow, very silty with quartz grains common, medium hard Marl, medium gray, with abundant clear quartz grains, very friable Siltstone, light gray with black specks, slightly calcareous, bentonitic Limestone, pale yellow, very silty, with abundant clear quartz grains, very friable Sandstone, quartz, very coarse-grained, unconsolidated clear grains, decreasing grain size at 165 feet; nunor limestone, pale yellow, silty, with laminae of clear quartz grains -- no phosphorite in the limestone Continuation, Clinch County 103 BASIC DATA 2 (Continued) CI2* (Continued) 170-175 175-190 190-195 195-217 217-225 225-245 245-250 250-277 277-290 290-294 294-302 Limestone, pale yellow, as at 125-145 Sandstone and limestone as at 145-170 Limestone, pale yellow, very silty, with clear quartz grains common, very friable; sharp decrease in phosphorite Limestone as above, with yellowish-brown iron oxide stain common on quartz sand aggregates and individual grains -- decrease in iron oxide stain at 200 feet Shale, pale greenish-gray, with black specks, siliceous; limestone, pale yellow, silty, friable Limestone as above; minor amount shale as above Shale as above, clayey; minor amount limestone as above Shale as above; clear quartz grains common Limestone, pale yellow, dolomitic Limestone, white, vuggy Limestone, dolomitic, light yellowish-brown, finely crystalline, pitted; limestone, pale yellowish-white, very finely crystalline, dense PHOSPHORITE 65-110; 125-217 (Minor phosphorite 195-217) CL3* 0-10 10-20 15-20 20-25 25-35 35-65 65-85 85-95 95-115 115-140 140-155 155-170 170-200 200-220 220-240 240-255 255-260 260-275 Sand, quartz, brown, unconsolidated Sand, quartz, yellowish-brown; clay, grayish-green Sand as above; clay absent Sand, quartz, pale yellowish-brown, unconsolidated Limestone, pale yellow, finely crystalline with abundant quartz grains Sandstone, light gray, calcareous Sandstone as above; siltstone, gray, calcareous, clayey, with quartz grains Sand (no consolidation), quartz, pale gray; sharp increase in phosphorite Sandstone, quartz, pale gray, calcareous, clayey Sandstone as above; interlayered green silty claystone Claystone, bentonitic; sandstone as above Limestone, gray, phosphatic, quartz grains Limestone, grayish-white, silty Limestone as above; minor amount chert, light gray Limestone, grayish-white, silty, abundant quartz grains; minor amount pale green sandy claystone Claystone, green, minor amount quartz grains Limestone, grayish-white, silty, abundant quartz grains (cavings?) Claystone as above Continuation, Clinch County 104 BASIC DATA 2 (Continued) CL3* (Continued) 275-290 290-297 297-300 Claystone as above; minor amount light gray chert Limestone, grayish-white, silty, abundant quartz grains Limestone, dolomitic, pale yellowish-brown, vuggy, hard, quartz grains CORE 60-61 PHOSPHORITE 25-170 0-10 10-25 25-30 30-40 40-50 50-60 60-75 Sand, quartz, pale reddish-brown, coarse-grained Sandstone, quartz, reddish-brown and yellowish-brown, interlayered greenish-gray claystone Sand, quartz, yellowish-brown, very coarse-grained Sand as above, white feldspar grains common Sandstone, quartz, yellowish-gray, fine- to medium-grained, friable Limestone, pale yellowish-brown, silty, friable, abundant quartz grains Limestone as above, minor amount grayish-green siltstone PHOSPHORITE 50-75 CL5* 0-5 5-15 15-30 30-40 40-65 65-70 70-80 80-85 85-90 Sand, quartz, pale yellowish-brown, very coarse-grained, unconsolidated Sandstone, quartz, pale orange, coarse-grained, friable Sandstone as above; claystone, pale greenish-gray, scattered clear quartz grains Sandstone, quartz, pale yellowish-gray, calcareous, friable; claystone as above Sandstone, quartz, pale yellowish-brown, fine-grained, very friable, abundant silt-sized particles, displaying metallic luster (heavy minerals?) Siltstone, medium gray, slightly calcareous; minor amount sandstone as above Sandstone, quartz, pale yellowish-gray, calcareous, friable Limestone, pale yellow, abundant quartz grains; minor sandstone as above Sandstone as at 70 feet MINOR PHOSPHORITE 60-90 Continuation, Clinch County 105 BASIC DATA 2 (Continued) 0-55 55-70 70-85 85-95 95-115 115-180 180-190 190-210 210-230 230-235 235-255 255-260 260-282 282-285 285-289 Sand, quartz, mottled red, yellow, brown and gray, clayey, quartz grains very coarse-grained -- increase white feldspar at 30 feet Sand, quartz, medium gray, yellowish-brown iron oxide staining, coarse-grained, clayey Sand as above; siltstone, pale greenish-gray, slightly calcareous, containing clear quartz grains; minor influx limestone, pale yellow, sandy Limestone, pale yellow, sandy; siltstone, pale greenish-gray, marly, containing clear quartz grains Marl, yellowish-brown, clear quartz grains; interbedded with limestone, pale yellowish-brown containing abundant quartz grains -some clastic limestone fragments (all containing phosphate) bounded by laminae of pure, fine, silty, pale orange limestone Limestone, pale yellowish-gray, silty, friable, clear subrounded fine-grained quartz grains Limestone as above; minor influx limestone, pale yellowish-brown, very finely crystalline, hard, pitted; chert, gray Limestone as above; increase in chert, gray Limestone, pale yellowish-gray, silty and clayey, friable, clear quartz grains; minor amount chert, probably cavings Limestone as above; shale, pale greenish-gray, mottled with black specks, siliceous Shale as above Limestone, pale yellowish-gray, silty and clayey, friable, abundant clear quartz grains and pale orange phosphate (?) pellets Limestone as above; interlayered shale, pale greenish-gray, mottled with black specks, siliceous; orange pellets absent Limestone, dolomitic, pale yellowish-brown, abundant quartz grains, scattered dark green translucent grains, moderately hard Limestone, dolomitic, pale yellowish-brown, very finely crystalline, pitted, quartz grains absent PHOSPHORITE 55-185 (Very little phosphorite 55-70) CL7 0-5 5-15 15-40 40-90 Sand Clay, blue, sandy Clay, white Clay, blue CL8 (Continued) 25-45 Clay 45-60 Sand 60-75 Clay, blue PHOSPHORITE 40-90 PHOSPHORITE 45-60 CL8 CL9 0-5 Sand 5-20 Clay 20-25 Sand 0-35 Clay, sandy 35-38 Rock 38-75 Clay MINOR PHOSPHORITE 65-75 Continuation, Clinch County 106 BASIC DATA 2 (Continued) CIJ..O 0-20 20-25 25-55 55-75 Clay, white and red Clay, sandy Clay, white Clay, blue MINOR PHOSPHORITE 55-75 CLll 0-20 20-45 45-55 55-75 Sand; sandy clay Clay, sandy Clay, white Clay, blue, sandy CORE 55-58 PHOSPHORITE 45-55 CL12 0-20 20-42 42-43 43-75 Sand; sandy clay, white Clay, blue, sandy Rock Clay; limestone layers MINOR PHOSPHORITE 70-75 CIJ..3 0-15 15-40 40-75 75-90 Sand Clay, blue and white, sandy Clay, blue; limestone layers Clay, white; limestone layers MINOR PHOSPHORITE 50-90 CL14 0-10 10-20 20-30 30-75 Sand Clay, white, sandy Clay, red and green Clay, blue NO PHOSPHORITE CL15 0-30 30-60 60-96 96-98 98-170 170-190 190-196 196-210 210-220 220-225 225-235 235-257 257-270 270-275 275-291 291-295 Sand Sand; sandy clay Clay, sandy; limestone layers Rock Sand; limestone layers Clay; limestone layers Limestone, white, sandy Clay; limestone layers Clay Limestone Clay Clay; rock layers Clay, hard Limestone, sandy Clay Limestone, brown PHOSPHORITE 65-170 CL16 0-20 20-42 42-55 55-70 70-90 Sand; clay, white, sandy Clay, brown and white Clay, blue Clay, blue, sandy; limestone layers Clay, white, sandy; limestone layers PHOSPHORITE 55-90 CL17 0-20 20-45 45-65 65-80 80-90 Sand Clay, white, sandy Clay, blue Clay, white, sandy Clay, light blue PHOSPHORITE 65-80 Continuation, Clinch County 107 BASIC DATA 2 (Continued) CL18 0-60 Sand; sandy clay 60-75 Clay, blue, sandy PHOSPHORITE 60-75 CL19 0-75 Sand; sandy clay MINOR PHOSPHORITE 70-75 CI20 0-30 30-40 40-60 60-80 80-90 Sand Clay, blue, sandy Clay Sand; sandy clay Clay, sandy PHOSPHORITE 40-90 CI21 0-30 Sand 30-55 Clay, white and brown 55-90 Clay, dark blue PHOSPHORITE 55-90 CI22 0-5 5-15 15-30 30-55 55-75 75-85 85-90 Sand Clay Sand Clay, light blue, sandy Clay, dark blue Clay, white Clay, dark blue PHOSPHORITE 55-90 Cl23 0-5 5-8 8-15 15-25 Sand Clay, red Clay, sandy Sand CI2 3 (Continued) 25-55 Clay, sandy 55-84 Clay, blue 84-86 Limestone 86-90 Clay PHOSPHORITE 55-84 CI24 0-5 5-30 30-40 40-45 45-55 55-70 70-82 82-85 85-90 Sand Clay, sandy Sand Clay, light blue Clay, white Clay Clay Limestone Clay; limestone layers PHOSPHORITE 70-82 CI25 0-5 5-45 45-55 55-70 70-80 80-90 Sand Sand; sandy clay Clay, white, soft Clay, blue, soft Clay, black Clay, black; limestone layers PHOSPHORITE 80-90 CI26 0-30 30-45 45-55 55-90 Sand; sandy clay Clay, white, soft Clay, white, sandy Clay, blue and white; limestone layers CORE 60-63 PHOSPHORITE 55-90 Continuation, Clinch County 108 BASIC DATA 2 (Continued) CI27 0-18 18-30 30-55 55-85 85-90 Sand; sandy clay Clay, white Clay, light blue, soft Clay, blue; limestone layers Clay, white PHOSPHORITE 55-85 CI28 0-3 3-J2 J2-30 30-35 35-70 70-90 Sand Clay, sandy Clay, light green Rock layers Clay Rock layers PHOSPHORITE 35-70 Cl29 0-5 5-20 20-30 30-40 40-70 70-90 Sand Clay, sandy Clay, light green Clay, white Clay, blue Clay, white PHOSPHORITE 30-90 CL30 0-20 20-40 4o-6o 60-70 70-90 Sand; sandy clay Clay, green and white, hard layers Clay, blue and white Clay, blue Clay; limestone layers MINOR PHOSPHORITE 40-60 CL3l O-J2 J2-40 40-65 65-70 70-90 Sand Clay, blue; rock layers Clay, blue and white Clay Clay, white PHOSPHORITE 40-90 CL32 0-10 10-45 45-60 60-90 Sand Clay; rock layers Clay, white; rock layers Clay; limestone layers CORE 60-65 PHOSPHORITE 45-90 CL33 0-30 30-34 34-44 44-55 55-75 75-90 Sand; sandy clay Rock Clay Clay, hard Clay Clay, dark blue PHOSPHORITE 34-44 CL34 0-10 10-20 20-65 65-90 Sand Clay, sandy, hard Clay Clay, white and blue PHOSPHORITE 40-90 Continuation, Clinch County 109 BASIC DATA 2 (Continued) CL35 0-5 5-15 15-30 30-55 55-70 70-90 Sand; sandy clay Clay, sandy, hard Clay, white and red Clay Clay, white Clay PHOSPHORITE 55-90 CL36 0-15 Sand; sandy clay 15-30 Clay, light green 30-40 Clay 40-90 Clay; limestone layers CORE 45-48 PHOSPHORITE 30-90 CL37 0-12 12-20 20-45 45-60 6o-63 63-90 Sand; sandy clay Clay Shells Clay Clay, hard; limestone layers Clay; limestone layers CORE 55-60 PHOSPHORITE 40-90 CL38 0-25 25-55 55-70 70-90 Sand Sand; sandy clay Sand Clay HOLE CAVED at 25 feet NO LOGS PHOSPHORITE 70-90 CL39 0-5 5-10 10-33 33-70 70-75 75-90 Sand Clay Sand; sandy clay Clay, blue Clay, sandy Clay PHOSPHORITE 70-90 cL4o 0-5 Sand 5-10 Clay 10-70 Sand; sandy clay 70-90 Clay, sandy NO PHOSPHORITE CL41 0-5 5-10 10-25 25-60 60-75 75-90 Sand Clay Sand Clay, sandy Clay, white, soft Clay, blue PHOSPHORITE 75-90 CL42 0-5 Sand 5-10 Clay, sandy 10-75 Sand; sandy clay NO PHOSPHORITE CL43 0-5 5-50 50-70 70-90 Sand Sand; sandy clay Clay, sandy Clay, blue MINOR PHOSPHORITE 70-90 Continuation, Clinch County 110 BASIC DATA 2 (Continued) ClJ+4 0-5 Sand 5-47 Clay, sandy 47-75 Clay, blue NO PHOSPHORITE 0-40 Sand; sandy clay 40-75 Clay, blue NO PHOSPHORITE cV+6 0-5 5-30 30-40 40-75 Sand Clay, sandy Clay, white Clay, blue MINOR PHOSPHORITE 60-70 0-40 40-75 75-90 Sand; sandy clay Clay, blue Clay, blue; limestone layers PHOSPHORITE 75-90 clJ+8 0-2 Sand 2-32 Sand; sandy clay 32-80 Clay, blue 80-90 Clay, blue and white PHOSPHORITE 6o-90 CL50 0-40 Sand; sandy clay 40-70 Clay, blue 70-90 Clay, blue and white PHOSPHORITE 70-90 CL5l 0-55 55-60 60-75 75-90 Sand; sandy clay Clay, blue Sand; clay Clay; limestone layers PHOSPHORITE 60-90 CL52 0-35 Sand; clay 35-75 Clay, blue; sand layers MINOR PHOSPHORITE 70-75 CL53 0-35 Sand; sandy clay 35-75 Clay, blue NO PHOSPHORITE 0-40 Sand; sandy clay 40-75 Clay, blue NO PHOSPHORITE *Samples checked and some descriptions modified by the writer. 111 BASIC DATA 2. Driller's logs. [All depths in feet. Symbols (CHl) indicate hole numbers.] CHARLTON COUNTY CHl 0-5 Sand 5-30 Sand, black 30-60 Sand, brown 60-75 Clay, sandy NO PHOSPHORITE CH2 0-50 Sand 50-75 Clay, sandy NO PHOSPHORITE CH3 0-40 40-55 55-57 57-65 65-90 Sand Clay, blue, sandy Rock Clay, blue Limestone; shells PHOSPHORITE 80-90 CH4 0-40 Clay, sandy 40-75 Shells; clay NO PHOSPHORITE CH5 0-75 Sand; sandy clay PHOSPHORITE 65-75 CH6 0-50 50-53 53-57 57-60 60-62 62-70 70-75 Clay, sandy Rock Clay Rock Clay Rock Clay NO PHOSPHORITE CH7 0-38 Sand 38-43 Clay, blue 43-71 Clay; limestone layers 71-75 Clay NO PHOSPHORITE CH8 0-75 Clay, sandy NO PHOSPHORITE CH9 0-75 Sand; sandy clay, black, brown NO PHOSPHORITE CHlO 0-65 Sand 65-75 Clay, sandy NO PHOSPHORITE Continuation, Charlton County 112 CHll 0-50 Sand 50-70 Clay, sandy 70-75 Clay, blue NO PHOSPHORITE CHl2 0-65 Sand 65-75 Clay, sandy NO PHOSPHORITE BASIC DATA 2 (Continued) 113 BASIC DATA 2. Driller's logs. [All depths in feet. Symbols (LAl) indicate hole numbers.] LANIER COUNTY LAl 0-22 22-38 38-45 45-60 60-95 95-105 105-115 115-120 120-150 150-160 160-173 173-177 Sand Clay Clay; rock layers Clay; chert layers Clay; limestone layers Clay; thick limestone layers Clay Limestone, brown, sandy Clay Sand; rock layers Sand Limestone, white and brown LOST CIRCULATION PHOSPHORITE 38-45 AD1. I;! M/ TIFTON 34 Ml l.AK1...AN0 3 Ml HO ME;RVILLE; 7 MI . PLATE I WAYCROSS 19 Ml N A >iUNTA 15 Ml ::};~~i~~4~~~ "" .....,_ N. i "20 'u' I\... "'"" (,._...' ' ( , . )' - --~;9I--\~. - _,- .:w. - ~- "'!!o- I ~ - .,_ ........ ) . - -::..~- (' I I- I I t --- -- .J 1 ''' ' u 0 0 0 0 CRO SS CITY H MI. BASE FROM USGS VALDOSTA SHEET 18 Ml TO U 5 . !>8 IJ I Mle!> 0 5 E3o - 11l'.-> ~=='=''==!?I0 -----'-.~f~, ======~JO K1 lomt ers ".r::.=::E'='=<==::E'=""==~===o==o==='="'='=~5========= ~~10====~==~==~315Nau tocal Moles EXPLANATION e PHOSPHORITE TEST HOLE CONTOUR INTERVAL 50 FEET WITH SUPPLEMENTARY CONTOURS AT 25 FOOT INTERVALS TRANSVERSE MERCATOR PROJECTION STRATIGRAPHIC-STRUCTURAL TEST HOLE ')( NO PHOSPHORITE PRESENT PV PLIOCENE VERTEBRATE REMAINS roR r w HI! ~ " ' H I(;H S ..R INGS 12 "" I 100 000 (;A I N!:SV j ~ L 29 M l $TA~l'l< 4 M l PHOSPHORITE DRILLHOLE LOCATIONS IN LOWNDES, ECHOLS, CLINCH, AND CHARLTON COUNTIES, GEORGIA PREPARED BY THE SOUTHERN RAILWAY SYSTEM IN COOPERATION WITH THE DEPARTMENT OF MINES, MINING AND GEOLOGY AOEL r2 Of/ 1..11./((LAND :) /WI PLATEN WAYCROSS I. Ml NAHIJNTA /:J ''" . - - - ~ - _-.t2F ..... ......... ..._ ..,_ ~- - .....,_ r~~t~f'i~~~s~~-~~~;~~~~~: +---=- ~ ~"""~''~w- - "~~ 3 " i 0 ~ < ' ' T ' S ' - CHO'S'S CITY JS Ml HIM/ rou s ~6 BHANIORU 7 Ml UHANI .....U .J Ml RI ~lSi;-:- '"' { .......... \ ( )---.1,~~ '89 \. ... '-:...-' I I . CH0$5 Cl rY JS Ml Base from USGS map 18 "'' TO U S !HI fJH,A.NI 0/'10 5 Ml Scale I :250,000 0 10 , 0 E3 E3 E3 10 ==r EI:>"='=''='"-""=~'~O=::.-=:=:=='E''=''=''=''=''=',3JO Kolome!ers 'c=:::E'=='l==:E'=3:==oi===='======--==i'=====-====---==I~Oi,=''='='='='='='='='=~!5Nauocal Mlll!s CONTOUR INTERVAL 50 FEET WITH SUPPLEMENTARY CONTOURS AT 25 FOOT INTERVALS TRANSVERSE MERCATOR PROJECTION rORT WHI/ 5 Ml 1-f/GN SPRING$ l;t Ml EXPLANATION ....................................................................................................... ANT ICLINE STREAM LI NEAMENT STREAM LI NEAMENT (GROSS FEATURE)