A second report on the public roads of Georgia

GEOLOGICAL SURVEY OF GEORGIA
S. W. McCALLIE, State Geologist
BULLETIN No. 24
A SECOND REPORT
ON THE
PUBLIC ROADS
OF
GEORGIA
BY
S. W. McCALLIE
State Geologist
.ATLANTA, GA.
CHAS. P. BYRD, State Printer 1910

PREFATORY NOTE
In submitting this report on the public roads of Georgia to the public the writer wishes to express his thanks to the State Pr~son Commission for valuable assistance in the co-operative work of collecting data on the roads of the State. Special thanks are also due to Capt. Goodloe H. Yancey, Secretary of the Prison Commission, who rendered invaluable aid in compiling the statistical data. In addition to the assistance here accredited, the writer wishes, furthermore, to express his gratitude to the various public road officials throughout the State for information concerning the public roads of their respective counties.
This report is the second report on the public roads of the State published by the State Geological Survey. The first report was issued in 1901. This report may, in a measure, be considered an abridged form of the report of 1901, with the addition of a large amount of statistical data brought up to date with additional matter added. It is to be regrett~d that the statisitcal data which were collected by correspondence with the county road offidals had to be estimated, in many cases, however, they are thought to he sufficiently accurate to give a fairly trustworthy idea of the general conditions of . the public roads of the State.

THE ADVISORY BOARD
OF THE
Geological Survey of Georgia
In the Year 1910
(Ex-Officio) Hrs ExcELLENCY, JOSEPH 11. BRO\VN, Governor of Georgia
PRESIDENT oF THE BoAnD
HoN. PHILIP COOK___________________ Secretary of State HoN. J. P. BROWN______________________ State Treasurer lioN. vV. A. \IVRIGHT---------------- Comptroller-General IIoN. JOHN C. HART ___________________Attorney-General IIoN. T. G. HUDSON _________ Commissioner of Agriculture lioN. J. M. POUND ________ Commissioner of Public Schools

LETTER OF TRANSMITTAL
GEOLOGICAL SuRVEY oF GEoRGIA,
ATLANTA, .Tune 15, 1910.
To FEis Excellency, JosEPH M. BRowN,, Gove1rnor, and President of the Advisory Board of the Geological Survey of Georgia.
SIR: I have the honor to sulJmit herewith a second report on the Public Roads of Georgia, to he published as Bulletin No. 24, of this Survey.
Very respectfully yours, S. W. !1o0ALLIE, State Geologist.

T.~.t\BLE OF CONTENTS

Page

PREF.ATORY NOTE_---------------------------------------- 7------

9

MILEAGE, EXPENDITURES AND OTHER PUBLIC ROAD DATA __________ 11-16

ROAD-BUILDING :MATERIALS OF GEORGIA___________________________ 17-23

Road-building materials of the Paleozoic area_------------------ 17-20 Knox dolomite _________________ ---------________________ 17-18

Chickamauga limestone___________________________________ 18

Bangor limestone _______ - _____ - ______ -_~_________________

18

Chert __________________________________________________ 18-19

Shale_________________________________________________ ~ _ 19

Sandstone----------7----------------------------------- 19-20 Road-building materials of the Crystalline area__________________ 20-22
Granites-_-_-_-_---------------_-----------_-------_-___ 20 Gneiss__ -_-_-_-------_-_-----------------------------___ 20-21 Diorite_________________________________________________ 21 Trap or diabase _________________________________________ 21-22
Road-building materials of the Coastal Plain __ - ___ -_____________ 22-23 Limestone------------------------~--------------------- 22 Gravel_________________________________________________ 23 Clay___________________________________________________ 23
RoAD CoNSTRUCTION _________________ ---- ____ --- __ --- ____ .:.______ 23-37 Location of roads_____________________________ ------_________ 23-25

Grades----------------------------------------------------- 25-26 Drainage--------------------------------------------------- 26-28 Road Surfaces ________________________________ -------_---___ 28-37
Stone--------------~------------------------------------ 28-30 Gravel _____________________________________ -.-----_---_-- 30-31 Sand-clay_________________________________ -_- ____ ------- 31-37

Public. Roads of Georgia
MILE~ti_GE -~ND EXPENDITURES
The statistical table of this report shows that the estimated public road mileage of the State of Georgia in 1909 was 82,182. Of this mileage, 554 miles were surfaced with stone and 56 with shells; 502 miles, with chert and gravel; and 3,421 miles, with sand-clay mixture. In addition to these more highly improved r,oads, there were also reported 13,156 miles of road which had been put in order by the use of the road machines, drags, etc. Omitting the 13,156 miles of roads which have been only partially improved, we still have a total of 4,533 miles of road surfaced with stone, shells, gravel, chert, and sand-clay mixture, which constitute about five per cent. of the total road mileage.
Of the 146 counties of the State, 107 employ convicts and 39 use statute or hired labor, the total number of convicts employed being 4,579.
The expenditures on public roads and bridges in 1909 were $1,437,652 property tax, $558,328 commutation tax and $61,000 bond issue, a total cash expenditure of $2,056,980. To this sum should be added $450,000, the estimated money value of the statute and the free labor employed in the State on the public roads. This makes the grand total for all road expenses for the year $2,506,980. In comparing the total road mileage of the State with the total estimated road expenditures it will be seen that each mile of public road cost last year $30.51 or $1.08 per inhabitant based on the census of 1909.

PuBLic RoAD DATA OF GEORGIA QoLLECTED BY THE. STATE GEOLOGICAL SuRVEY IN Co-OPERATION wi'lH THE STATE PRISON CoMMISSION.

MILEAGE .OF ROADS.

COUNTY

IMPROVED ROADS.

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Appling _________ Baker___________.

583 '366

600 -- -- -- -275

Baldwin _________ Banks __________

250 335 216 -- _300

15 69 s-c $ 400 35 50 s-c 300 30 . 175 --------
10 --------

Bartow ____ Ben Hill __ -~ ~~ ~~

485

1 ,000 250

50

60

--s-c

---2-o-o

Berrien _________ Bibb ____________ Brooks__________ Bryan __________

254 463 427

1 ,200 500 450 600

20

20

5 s-c .500

200 300 --------

200

400

53

100

Bulloch _________ Burke __________

930 _883

900 700

50 700 s-c 400 400 300 s-c 400

Butts ___________ 179 300

--------

Calhoun _________ Camden _________

276 718

210 -- -- ---- -- ---
275 10 -- -- -- ---

125 --------

275

250

CampbelL _______ 205 CarrolL _________ 486

465 800

-- --
12

--
--

--
--

---

-----

--

30
----

--------
2,000

Catoosa _________ 171

Charlton ________ Chatham ________

1063 400

200 200 220

---

--
--
1

30
-- --
105

-- ---- -------

--
--

-- --
30
-- --

--------
100 3 ,500

Chattahoochee ___ 231 262 ---- -- -- -- --- -- -- -- --------

Chattooga _______ Cherokee ________

326 434

1

350 ,000

----

-- --

-- --- -- -- -- -- -- -- --

10 2.5

250

Clarke __________ 159 147 8

38 50 s-c 650

:a LABOR USED .s
IN ROAD IM- ::l
PROVEMENT. p, ~ 0

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EXPENDITURES FOR ROAD

;:?

IMPROVEMENT

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PROPERTY TAXl.
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I$ 15 $ 60 $ 30 6$ _____ 1 .4oo $ 3 ,342 $ 8 ,5311$24 ,000

20 50 35 65 31 50 60 60 28 . 50 31 70 139 150 53 100 20 ioo 41 150 64 125

25 4 700 650 4,000

35 20 4,500 1 ,000 3,000

25 18 4,500 1 ,000 -------

30 30 7 ,500 2,000 7 ,000

25 14 4,000 800 400

30 -- ---
40 65

600 13 ,000 .

5,000 7 ,500 3,500 -------

30 30 6,000 1 ,200 8,500

25 8 1 ,000 700 1,300

30 34 6,800 1,800 9,000

40 30 6,000 1 ,100 10 ,000

6 ,000 '-- -- --11 ,000 ------
2,810 2,810 11 ,852 11 ,852 23,810 5,952
4,989 ------44,043 5,110
5,125 ------1 ,600 ------10,330 ------7 ,318 -------

a
21 13 16 37

--

--
83 65 75 45

--

--
25
30 30 35

----14
6 23 14

-------
3 ,000
1 ,000 5 ,000 3 ,000

-------
800 ioo 1 ,000 10,000

-------
4,300
2~500
5,000 10,000

---------
9 ,500 2,000 4,444 12,000

-------
850 1 ,500 5,555 12,000

a 22

- - ~--
65

-- --
25

--- --- ---

--------------

-------
100

-------
1 .200

153 100 50 23 4,600 3,000 -------

2.254 ---- --2,167 ------40,000 -------

a -- -- -- -- -- --- ------- ------- ------- --------- -------

a 40

-- --
75

--

--
30

--

---
24

-------
6,000

-------
1 ,500

-------
8 ,000

---------
4,404

-------
2,936

86 125 35 46 11 ,500 6,500 2,500 --:------- -------

rn "d l
8... ..0..
.<:".:1.'ll
=t::.
"drn
j:j<ll <!)Oil
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$35,873 10,000 14,000 5,620 30,704 30,162 12,489 49 ,153 13,625 2,900 19 ,330 17 ,318
-------
14,650 6 ,000 14 ,,999 34,000 2,254 3 ,367 40,000
-------------
15,340 b20,000

1.l:!:stimate made on ta:JC returns for 1908.

--

-----~-

Qlay .. ----------- 216 360 ____ ----

7

Qlayton ____ -- --- H2 aoo____ ____ _____

75 s-c 125 ao________

Clinch _____ -- -- - 1077 4oo 10 _________ 1oo ________

Cobb ________ - _- 821 800 15 __ --

6 201m 3,000

Coffee___ .. __ ----- 920 Colqui~t- ____ ---- 565 Columbia____ ---- 306

950---- ---- 30

700 ---- ----

7

350 ______ -- ____ -

6 s-c tlQO
400 s-c aoo 850 s-c 300

Coweta. ____ ---- 443 800

25 150--------

Crawford ___ .:---_ 834 300 ____ -----------------------

Crisp ---- ------- 285 450 ----------- 200________

Dade ___ -------- 188 145____ 10______ ______ ________

Dn wson _______ -Decatur ________ _ DeKalb ________ _

209 766 271

300 ____ -----------------------

1 ,000---- ---- 100 150

50

1 ,300 16 __ -- 15 600 6 ,500

Dodge ___ - __ ---- 495 450 __ __ __ __ 25 350 s-c 350

Dooly______ ----Dougherty___ -- __

400 339

700----- ---- ----350 10_________

500 ---- -- -250________

Douglas ______ - __ 212 400 ___________________________

Early. __ -------- 503 1 ,000 __ ___ __ __ 50 100 s-c 100

Echols ______ ---Effingham _______ _

365 419

175---- ----------------------500 __ -------------------------

Elbert_ _____ ---- 388 700 __ __ __ __ 20 100 s-c 1,400

BmanueL ______ -- 776 1 ,000 __ __ __ __ 40 250 s-c 250

Fannin________ -;Fay'et.te ____ -----

3 9 0 215

200 -- -- -- -- -- -- - -- -- -- -- -- -- -300---- ---- ----- ------ --------

li'loycL __ -- __ ---- 50G 800 10() -- -- ------

30

760

Forsyth_______ -Frauldin ______ _

252 281

600 500 ____ ---

------ -- 7 --~-~

1 17

100

Fulton ______ ---Gilmer ________ _
Glascock _____ - _ Glynn_______ _

1?4 400 300_________ 25 ________

450 1,000

--------------

95 200 ____ ---- 50______

30

468 150 20 ________ ------ s 2,000

Gordon ___ .. __ - _ Chacly ________ _ Greene _________ _
Gwinnett______ _
Habersham ____ _ Hall .. _________ _

387 400 -- -- -- -- -- --- -- -- -- -- -- -- --

453 400 ____ ... --------------------

t!QO 850 31 3 3 ______

200

510 1 ,0001 __ -- ---- -- ---

35 --------

280 4001_'"' ~- ,____ -- ___, _______ -:- __ __

tl49 Goo 8! _______________ ),5oo

---~-~----

18 75 ao 10 2,500. 1 ,000_ ---

4,103 ______ _

48 10 ao 27 6 ,ooo a ,ooo

5 0

2,620 ______ _

a4 40 25 _________________ a,o 0 __________ -------

65 125 35 42 60 ao

34 6,800 1 ,575 7 ,5 0 20 5 ,000 300 6 ,0 0

12 ,443 11 '199 7,366 ______ _

26 60 30 14 3 ,500

800 6 ,5 0 __________ -------

27 60 25 16 3 ,000

900 2 ,0 01

3,591 ______ _

56---- 30 26 6 ,000 2 ,500 8 ,0 0 25,186 4,407

CL _____

2 400 135 ____ _

2,869 ______ _

23 75 25 15 3,000 4,000 2,0 a _______________________________ _

0\

6 '745 -- ---2,327 ------

a. -------- ---------- ------- ---

80 150 40 G5 90 35 25 75 20

81 GO 16

16 ,000 18 ,000
4 ,000

5 ,000 ~10 ,000
2 ,000

10 ,0 5 ,0 6 ,0

0 0 0

43 100 40 23 L1 ,L!OO (3 ,000 10 ,0 0

49 75 35 24 6,000 6,000 3,0 0

a.

------

6 1,300

260 1,9 0

43 75 35 20 4 ,000 9 ,000 7 ,0 0

a. ------------------- -------

13,000 4,000 14,000 7,000
7 ,248. 5,43G 6,383 ______ _ 6,500 ______ _ 3 ,500 ______ _ 16,000 ______ _

20 75 30 34 50 30

L]
~2

1,030 5 ,000

'750 3 ,000

3,0 '1 ,5 001

36 45 25 24 6 ,000 1 ,500 8 ,0 0

a. -- -- -- -- - . - -- -- -- - -- -- -- - -- - - -

65,,0600001 _____-_-_-_--_ 18,000 2,000

20 Ll5 25
53 166 50

8 64

1 ,400 14 ,400

GOO 16 ,000

'7
11 ,0

01
0

2 ,4381 853 22,118 10,397

G, - - - - - - - - - - - - - - - - - - - - - - - - - - -

20 75 35 16 3,600 ___________ _

549 300 37 235 58,750 40,000 8,0 0\ a. ------------ -------------------

35____ 39 100 50

6 4

1,200 350 400 _______

2,1 2,3

01 0

4 ,886 4 ,88,6 210 ,000 -------
842 3,000
1 '100 -- -- -- 6,581 ______ _

a. -- -- -- -- -- --- -- -- -- - -- -- -- - -- -- -

6,000 ______ _

a. --------------------------------

23 45 25
63 60 tl() a ___ __ __ __ a. ________

26 27

6,000 5 ,4~0

1,200 1 ,000

6,0 01 '

4 4

1 , loO 800

150 1,5oo

3 6

,8 ,0

b51
00

5,774 5,774
29,635 4,939 3,000_______ 6,800_______

4,103 3 ,120 3 ,000 31,142 13 ,366 6 ,500
5 ,591
37 ,593 2,869 8,745 2 ,32'7
27 ,000 26,000 18 ,684 16 ,383
9 ,500 5,460 23 ,000
8,600 ]3 ,500 28,000
;) ,991 43 ,515
9,772 218,000
3,842 3,200 8 ,881 6,000
17 ,548 34,574
6,855 12,800

COUNTY

MILEAGE OF ROADS. '

LABOR USED IN ROAD IM-

.;!g":')

PROVEMENT. p.

IMPROVED ROADS.

1'1
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EXPENDITURES FOR ROAD

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IMPROVEMENT

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PROPERTY TA.,"'C.

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Hancock ________ 523

Haralson ________ 282

Harris __________ 486

Hart________ -- __ 257

Heard __________ Henry __________

313 337

750 ---- -- -- 25 300\s-c $ 25

500 ---- -- -- ----- -- -- -- -- -- -- --

500 -- -- ---- ----- -- -- -- --------

500 ---- -- -- -----

25 -- -- -- --

310 -- -- ---- 10 -- ---- --------

900 -- -- ---- -----

30 --------

Houston_-,- _____ Irwin ___________ Jackson _________

591 459 460

1,400 -- -- -- --
175 1,000 ---- ----

. 50 800 8-C 50
45 25 s-c 125 10 . 100 s-c 400

Jasper ___ ~-----Jeff Davis_______ Jefferson ________ Jenkins _________ Johnson _________ Jones ___________
Laurens _________ Lee _____________
Liberty _________ Lincoln _________ Lowndes ________ Lumpkin ________ Macon __________ Madison _________

410 395 686 400 258 397 791 436 976 290 455 282 392 278

450 -- -- -- -- -- --- -- ---- --------

500 565

----
----

---

--
--

-----
'100

---- --
400

--------
8-C 250

190 ---- ---- ----- 130 --------

200 -- -- ---- 35 110 8-C 50

600 ---- -- -- 50 100 --------

1,310 -- -- ---- 65 95 s-c 700

800 ---- ---- 10 200 8-C 500

500 ---- ---- ----- -- ---- --- . -- --

900 ---- -- -- -- --- 100 --------

1,250 ---- ---- 60 -- -- -- s-c 700

400 -- -- -- -- -- --- ------ --------

550 ---- ---- 15 ---- -- 8-C 400

950 -- -- -- -- -- ---

10 --------

MMcaDriuoffnie--_-_-_-_-_-_-_--_1324548

300 -- -- -- -- 25

400

100

50 8-C 200 25 8.-c 50

35 $ 75 $ 30 28 $ 5,870 $ 2,500 $ 6 ,500 $ _______ $ 2,000 $ 8 ,500

a ---- -- --

------- 3,000 -------

4,831 -------

4,831

a -- -- ---- ----- -------
24 50 30 12 2,400

500 700

------- --------- ---------
4,600 3 ,750 3,750

-------
12,100

26 75 40 8 1,800 450 ------32 100 30 21 4,600 1 ,100 7 ,500

2,200 750 2,950 6,549 12,281 26,330

40 75 30 26 5,000 1,500 4,000 7 ,000 5,000 16,000

26 75 25 32 75 35

14 3 ,150 1,250 ------19 5,000 2,500 12,000

7 ,500 3,000 1-,0,108 10 ,108

10,500 32,216

a -- -- ---- ----- ------- ------- ------- --------- -- ----- -- -------

a -- -- ----
29

-- --- ------- -------
30 6,200 1,200

------- --------- ---------
6,000 9 ,000 -------

-- --! --
.15 ,000

40 90 35 22 5,000 700 5,500 5,177 1 ,725 12,402

34 100 30 16 2,400 1 ,020 2.766 4,183 2,384 9,333

26 60 30 25 5,500 3,000 4,200 3 :346 2,007 9 ,553

58 100 30 41 10,000 2,000 n.ooo 5 ,883 ------- 16,883

32 85 30 21 4,500 2.000 4,000 4,500 1 ,795 10.295

a - -- ---- -- --- ------- ------- -------
10 50 30 15 3,000 2,500 3,500

3 ,701 ------4,000 -------

3,701 7 ,500

54 85 25 28 6,000 1 ,500 2,500 --------- -------

a -- -- ---- -- --- -- -- --- ------- -------
40 125 30 26 5,000 1 ,000 4,100

2,000 ------10,882 4,000

2,500 2,000 18,982

29 60 30 17 4,300 1 ,200 10,000 3,300 3,300 16,600

15 40 ---- 9 1 ,800 ------- 3 ,600 7 55 30 14 2,000 350 2,500

3,000 4,008

_-_-_-_-_-_--

6,600 6,508

~-~--~-

- - - - - .--~---~-~--

~---~--~-----~----------

---------

Mcintosh________ 429 150 5---- -- --- ------ --------

Meriwether ______ lVliller ___________

544 275

1 ,<100 ---- ---- .__ -50

10 --------

260 -- -- ---- ----- -- -- -- --------

Milton __________ 147 250 -- -- -- -- -- --- -- -- -- --------

MitchelL ________ 542 600 -- --- -- --- 30 200 s-c 200

Monroe _________ 480 1 ,000 -- -- -- -- -- --- -- -- -- -- -- -- ---

Montgomery ______ 642 800 -- -- -- -- ----- 100 --------

Morgan .. ________ 346 1 ,000 ---- -- -- 250 500 s-c 300

Murray _________ 352 250

20

--------

l\1 uscogee_________ 255 400 25

50

--------

Newton __________ 259 250 15

15 11 s-c 500

Oconee__ -~ ______ 184 350 -- -- --- --

2 ______ --------

Oglethorpe ______ 575 940 10 -- -- 50 30 s-c 500

Paulding ________ 329 700 -- -- -- -- ----- ------ --------

Pickens __________ 219 Pierce __________ 518

500 -- -- -- -- -- --- ------ --------

250 -- -- -- -- 10

75 s-c 200

Pike ____________ 294 PollL ___________ 292

900 -- -- -- -- -- --- ------ -------600 ---- -- -- -- --- -- -- -- ---------

PulaskL .. _______ <!77 580 -- -- -- -- 50 250 s~c 22

Putnam _________ 348 350 4---- 20 100 s-c 600

Quitman ________ 152 H.abuh ___________ 344

250 -- -- -- -- -- --- ------ -------400 -- -- ----- -- --- ------- --------

H..:i.ndolph _______ 476 050 -- -- -- -- 106 ------ ---------

H.iehmoncL ______ 272 900 7 100 80 100 g 1 ,600

Rockdale ________ Schley __________ Screven _________ Spalding _________ Stephens __________

121 ]88
654 203 155

238 -- -- -- -- -----

5 s-cl ,200

280 -- -- -- -- -- --- ------ --------

G25 -- -- -- -- 100 350 s-c 100

1 ,000 -- -- ----

5

22 s-c 250

340

15

8-C 350

Srewart _________ 440 6.90 Sumter___ ~- _____ 1534 1 ,150

I:j --------
100 -- ---- s-c 1 ,000

TalboL.- _________ 7 407 '.l'aliaferro _______ 198 TaU.nalL ________ 735 Taylor ___________ 338

414 -- -- -- -- -- --- ------- --------

400 -- -- -- --- -- --- ------ --------

950 -- -- -- -350 -- -- -- --

55 ------ s-c 265 5 ________ s-c 400

Telfair ___________ 412 400 -- -- ---- 50 100 --------

TerrelL __________ 340 800 -- -- -- -- 125

60 s-c 100

a

60 -- --

2 300

75

463 1 ,207 -------

1 .670

44 100 30 26 7 ,000 2,000 10,000 7 ,000 ------- 17,000

11 100 25 10 2,800

450 4,500 --------- --------

4,500

a ---- -- -- -- --- ------- ------- 3 ,000

GOO -------

3,600

41 65 30 3G 8,500 2,000 10,000 14,000 ------- 24,000

30 75 25 26 5,000 1 ,000 5 ,500 10,000 5,000 20,500

26 75 40 22 5,000 1 ,000 6,000 4,850 1 ,375 12,225

32 60 25 2G 6,500 ------- 4,000 --------- -------

4,000

a -- -- ---- -- --- -------

250 -------

4,022 -------

4,022

93 100 35 40 10,000 4,500 3 ,500 33 ,396 ------- 36,896

28 60 ---- 22 7 ,500 2,500 3,500 8,701 4,350 16,551

29 50 30 12 3,000 300 3 ,300 1 ,418 1 ,418 6,136

33 50 30 20 5 ,OOll 1 ,250 7 ,000 6 ,000 ------- 13 ,000

a -- -- -- ---

12 2,700 ------- 6 ,GOO

6,000 ------- 12,600

a 22 53

--- -- -- -- --- ------- ------50 22 2 450 200 85 35 35 7 ,500 2,000

------- --------- ----------

1 ,700

5,951 -------

5,000 9,404 1 ,567

-------
7 ,651 15,971

a

G5 -- -- 27 6,750 2,010 ------- 11 ,000 -------

11 ,000

38 100 40 i31 8,525 1 ,500 5,500 10,000 3,000 18,500

30 90 30 27 G,OOO 6,000 6,750 4,811 3 ,608 15,169

a -- --- ---- ----- ------- ------- ------- ---------- --------

a -- -- -- -- -- --- ------- ------39 G5 30 27 5,000 1 ,000
168 100 40 70 H,OOO 10,000
27 75 35 17 3 ,000 2 '750

4,000 7 ,300
900 3 ,500

2,000 ------5 ,000 -------64,000 ------4,282 4,300

-------
6,000 12,300
64,900 12 ,082

10 75 30 G 1 ,500 300 1 ,GOO 32 75 35 16 3.200 1 ,000 G,500

2,050 ------4,922 2,4G1

3,650 13,883

68 75 35 16 4,000 2,500 5 ,500 9 ,979 11 ,474 26 ,953

24 50 40 16 3,GOO 1 ,500 3 ,000 82 90 25 16 3,000 2,500 6,000

8,G88 ------- ll,G88 4 ,497 2,248 12,745

78 125 35 75 ~6 ,875 G ,000 6 ,500 --------- ------- 50,000

(/, -- -- -- -- -- --- ------- -------
16 50 30 12 2 .400 1 ,000

-------- ------------------
2,700 -- -- --- --- 2,500

-------
5,200

14 60 30 14 3,000 600 a --- -- -- -- -- --- ------- -- --- --30 75 25 14 3 ,500 1 ,500

6,500 9,000 -------
-------- --------- ---------
5 ,000 5 ,G16 4 ,212

' 15 ,500
-------
14,828

45 85 37 29 5,000 800 9,000 3 ,000 ------- 12,000

-----~----

COUN'J'Y.

-

----

-----

------~----

----

MILEAGE OF ROADS.

LABOR USED ~

IN ROAD IMPROYEMENT.

.0 ::I p.

!

:g.;; ~

IMPROVED ROADS.

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EXPENDITURES FOR

~

ROAD IMPROVEMENT.

"C"'l c;l 0

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PROPERTY TAX.

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tomas _________ 504 600 ---- -- -- 50 300 s-c $ 350 66 $1001$ 30 $ 47 $ 9 ,400 $ 1 ,850 $ 9,000$ 12,500 $__ ---- $ 21 ,500

1ft0_m__b-s -_-_-_-_-__-_-_-_-

271 519

350 -- -- ---- 90 380 ---- -- .... _ -----

40 8-c 200. 34 75 25 12 3 ,000 1 ,000 5,500 20 ------ _._ 26 100 25 16 4,000 1 ,200 3,500

9,300 3,000 5,668 -------

17,800 9 ,168

lWnS- _- ~- ----- 168 :oupe __________ 434 uner ______ -~ __ 326

150 -- -- ---- -- --- -- -- -- -------- a ---- ---- -- --- ------- ------- ------- --------- ------- ----------

()50 -- -- -- -- 15 ------ 8-C 600 39 75 30 19 4,000 2,105 6,322 11 ,550 -------

17 ,872

800

100 200 SC 125 26 75 25 21 4,500 1 ,000 3,000 4,600 2,000

9,600

~'iggs __________ lion ___________
oson __________ 'alker__________ alton__________
are ___________
arren _________

423
325 310
433 366 676 298

300

150 --------

200 ---- -- -- ----- -- -- -- -- -- -- --

. 400 ---- ---- --- ... - ------ -- -- -- --

563 ---- 234 -- ---

42

800

1 ,400

800 --------

300 '325

-------

----- --

--

8
---

--

-- -50

---------------

25 100 30 14 3,500 1 ,000 4,600 1 ,929 964

7 ,493

a ---- ---- -- --- ------- ------- -------

723 -------

723

a a

-------

----- --

---------

-------------

_-_-_-_-1--0-0

-------------

---------
10,000

-------------

---------
10,000

33 100 30 34 6,800 1 ,500 ------- 12,387 4,129 16,516

31 75 35 10 2,000 11 ,500 2,500 --------- ------16 60 30 18 4,500 1 ,000 4,100 --------- -------

2,500 4,100

ashing'ton _____ ayne__________ ebster_________ hite___________ hitfield ________ ilcox__________
wilkes _______ -~ _ wilkinson _______ worth __________

680 766 227 243 285 473 501 431 604

1 ,200 ---- ---- 200 50 s-c 300 55 .85 25 48 9,000 3 ,000 10,000 10,000 18,500

600 -- -- -- --

8

50 s-c 500 a ---- -- -- ----- ------- 5,700 2,500

5,106 2,042

228 ---- -- --

5 85 8-C 1,500 10 65 35 10 2,500

500 5,000

2,629 4,331

250 ---- ---- ----- ------ -------- a -- -- -- -- -- --- ------- ------- 3,300

800 -------

450 5---- ----- 150 -------- a ---- -- -- -- --- ------- ------- -------

8,000 -------

'800 ---- ---- ----- -- -- -- -------- 18 65 20 11 2,000 400 4,500 --------- -------

900 6---- ----- 100 -------- 34 60 30 22 4,000 3,000 6,470 6,918 2,421

500 -- -- ---- ----- -- -- -- -------- 20 40 25 9 2,200 1 ,500 5,000 2,641 3 ,301

800 ---- -- -- -- ---

400

--------

29 100 25
- -----

18 . 3 ,600 1 ,000 10,000

10,000 3,000

38,500
9 ,648 11,960 4,100 8,000 4,500 15,809 10,942 23,000

Total _____

82,182 610 502 3 ,421 13,156 -------- 4,579 -- -- -- -- 2,645 588 ,450 271 ,480 558 ,328 1 ,157,895 279 '757 2 ,056 ,980

~

n-Roads kept up by statute or free labor or by both. b-Total expenditure, includes money raised by taxation and bond sale.

c-"Otherwise improved" are

roads partially improved by road machines, drags etc.

It-The great variation in the cost of sand-clay roads is clue to the width of roaus, amount of grading, etc.

m-l\Iacad!1-mi11ed roads. sc-Band-clay roads.

y-Gravel road5.

s-8hell roads,

BOAD BUILDING 'MATEBIA.LS

17

ROAD-BUILDING MATERL~LS 1

In the discussion of the road-building materi.als of Georgia, it is well to divide the State into three divisions, namely, the Paleozoic Area, the Coastal Plain, and the Crystalline Area.
ROAD-BUILDING MATERIALS OF THE PALEOZOIC AREA
The road-building materials of the last named area, the Paleozoic, which comprises all or a part of ten counties in the northwestern part of the State, consist of limestones, cherts, shales and sandstones.
LIMESTONE.-The limestones of the area are very abundant and well suited for macadamizing purposes. They are divided geologically into three divisions, namely, the Knox do1omite, the Chickamauga limestone, and the Bangor limestone.
TRE KNox DoLOMITE is the most extensive of the three formations. It attains a thickness, in places, of more than 4,000 feet, and occurs in the form of a number of broad belts traversing the area in a northeast-southwest direction, giving rise, usually, to broad, rounded ridges. The formation consists. largely of compact, heavy-bedded, light-gray magnesian limestone, often oolitic and always containing a considerable amount of siliceous material in the form of chert. Its uniform texture and its semi-crystalline structure will adapt it for macadamizing purposes. It would, indeed, be a difficult matter to find a calcareous deposit better adapted for roadmaterial than some of the beds of this formation. The stone is easily quarried and is readily crushed by the rock breaker;
1. For a more complete discussion of the road materials of Georgia, see Bulletin No. 8 on Roads and Road Materials of Georgia, published by this Survey.

18

PUBLIC ROADS OF GEORGIA

but it has, at the same time, sufficient toughness to form a durable wearing surface.
THE O:HICKAMAUGA LIMESTONE overlies the Knox dolomite. It occurs in the form of narrow belts, more or less parallel and often valley forming. The formation is so-called from Chickamauga valley, where, in the neighborhood of Chickamauga Park, it reaches its greatest development. Its various beds differ considerably, both ~n physical structure and mineral composition. In its western exposure it is a blue, fl.aggy, highly fossiliferous limestone with S?me local variations of minor importance. The compact, blue variety of this stone makes an excellent macadam. It has been extensively used for this purpose both at Chattanooga and in Chickamauga
Park. It makes a hard, smooth road surface, comparatively
free from dust. The Chickamauga limestone varies from 1,000 to 1,80D feet in thickness and is the underlying rock in many of the narrow,, fertile valleys in Northwest Georgia.
THE BANGOR LIMESTONE is a pure, dove-colored limestone, attaining a thickness of about 900 feet. It is highly fossiliferous and contains, in places, crinoid stems in great abundance. The formation is well exposed along the flanks of Pigeon and Lookout mountains. The extent of the area covered by this formation is limited mainly to the narrow belts at the base of the above named mountains; and, as a consequence, it will probably never become of very great importance in road construction. However, its use for macadam in the vicinity of Chattanooga shows that it is well suited for that purpos~.
CHERT.-The chert deposits of the ~aleozoic Area are quite extensive and are widely distributed throughout the area. They occur in two' different' geological formations, namely, the I{nox dolomite and the Fort Payne chert, the latter being

ROAD BUILDING MATERIALS

19

the lowest member of the Carboniferous formation. The chert of the Knox dolomite is co-extensive with the dolomite ~tself, and is by far the more important deposit of the two, for road building material. It occurs in the dolomite in the form of nodules, and also in beds, frequently several feet in thickness. In the weathering of the dolomite, the chert remains as a residual product in the form of gray flinty nodules. This siliceous material frequently accumulates to the depth of many feet along the sides and slopes of ridges where it is often well exposed in railroad cuts. The chert is an impure variety of flint, frequently containing more or less calcareous material, an~ is readily crushed into sharp angular fragments. It has been extensively used for several years for surfacing roads and streets throughout North Georgia and Tennessee. The material is well suited for roads of light travel, but where the traffic is heavy it is inferior to limestone. It possesses an excellent binding qual-. ity, but afterlong drought and much travel it becomes some-. what dusty.
SH..&.LE.-The shales of the Paleozoic Area are of but little econQmic importance as road-building materials; howevBr, the shales in the vicinity of Rome have been used to a considerable extent for roa,d surfacing. This material makes a fair road surface; but it is objectionable, on account of its rapid wear and dusty condition during the dry season, especially when there is much travel.
SANDSTONE.-The sandstones of the Paleozoic Area are confined chiefly to Pigeon, Sand, and Lookout mountains. They are known as the Walden sandstone and the Lookout sandstone. The former constitutes the surface rock of the above named mountains, while the latter forms the cliffs and escarpments along thier slopes. The aggregate thickness of the

20

PUBLIC ROADS OF GEORGIA

formation~ is several hundred feet. These sandstones are so easily crushed that they are of but little value for road material.
THE ROAD-BUILDING MATERIALS OF THE CRYSTALLiNE AREA
Th~ road-building materials of the Crystalline Area consist of granite, gneiss, diorite, and trap rock.
GRANITE.-The granite is very generally distributed throughout the Crystalline Area where it occurs in the form of large intrusive masses in the gneisses and schists. These granitic mass~s often coyer hundreds of acres, and occasionally, as in the case of Stone Mountain,. form dome-shaped masses, ha.ving an elevation of seve:r:al hundred feet above the surrounding country. In texture the granites differ widely. The.y vary from an exceedingly fine-grained, homogeneous, monumental stone to a very coarse-grained granite or pegmatite. The fine-grained varieties are quite extensively quarried at ~everallocalities in the State for building and monumental stone; and also for street paving purposes. The physical tests, which have been made on these granites, show that they have great strength, and are therefore among the best of ~this class of stone for road material.
GNmss.-GneiS's is far more abundant in the Crystalline Area than granite; and, as a general rule, it is much more suitable for road material. The gneisses. are divided into two varieties, namely, the true ~neiss, made up of quartz, feldspar and mica, and the hornblende-gneiss, which contains, in addition to these minerals, hornblende as an essential constituent. Hornblende-gneiss is generally superior to the true gneiss for road purposes on account of its finer texture and
greater 'toughness. It occurs, in places, throughout North
Georgia, where ifisfound in narrow belts underlying the .so-

ROAD BUILDING MATERIALS

21

called" red l~mds." The great amount of iron which the rock carries adds probably to its binding quality. It wears well and is comparatively free from dust. The true gneiss makes a fair road-surfacing material, when it is fine-grained and composed largely of quartz. Nevertheless, it is usually inferior to hornblende-gneiss.
DroRITE.-Diorite, which is more or less abundant throughout North Georgia, is a green or dark gray rock resembling very closely in general appearance the hornblende-gneisses. It occurs mostly in the form of narrow belts or zones, intercalated with the gneisses and schists. }.!I:ost of the diorites of the Crystalline .~.L\..rea have a schistose or laminated structure which injures it for road macadamizing purposes. The diorites, when fine-grained and not too distinctly laminated, make an admirable road material, second oJ+ly to diabase. The toughness, hardness and binding quality of this stone are all excellent. Large exposures of this rock are to be seen throughout the Piedmont Plateau.
TRAP OR DrABASE.-Trap rock is very generally distributed throughout the Crystalline Area. It occurs always in the form of dikes, which have ~riginated from the filling of fissures by molten matter forced up from below. The dikes have generally northwest-southeast trend and a nearly vertical dip. They almost invariably cut the gneisses and the schists at a considerable angle, and rarely ever show any evidence of shearing or crust movement since their formation. All the larger dikes of Georgia, so far as known, are usually quite uniform in thickness, and frequently extend for many miles, with but few interruptions. A good example of one of the larger dikes is to be seen in a cut on the Central of Georgia Railway a few miles east of Newnan. This dike continues for about 65 miles in a southeasterly direction through Cow-

22

PUBLIC ROADS OF GEORGIA

eta, Meriwether and Talbot counties, finally disappearing beneath the recent sands about four miles south of Talbotton. c, These rocks are of dark gray or black. color, usually fine~ grained and quite difficult to break with a hammer. As a road-surfacing material, this class of rocks has no equal. Its great hard_n-ess and its remarkable toughness make it an ideal road-building material.

THE ROAD-BUILDING MATERIALS OF THE COASTAL PLAIN
The road-building materials of the Coastal Plain are limestone, clay .and gravel. In the vicinity of the coast, shells also have had limited use in road surfacing.
LrMESTONE.-The limestones of South Georgia outcrop at many points throughout the Coastal Plain. They are exposed most ahun_dantly along the streams and" in the vicinity of limesinks or lakes. . They are also occasionally seen in the cuts of the vq,rious railroads traversing this part of the State. These limestones are usually soft and of a porous nature; though, occasionally, they become quite compaCt and are partly crystallized. The softer varieties, in places, consist mainly of fragments of shells and a limited amount of sand cemented together by a calcareous matrix. This class of limestone has been used to a limited extent for road and street surfacing both in South Georgia and Florida, where it seems to give general satisfaction. It readily cements into a compact, hardened surface, comparatively free from dust. This material has been used in the last few years on so~e of the streets in the city of Macon, where it has given fair re.gults. The hard limestones of South Georgia appear to have had but little use, so far, in road construction; nevertheless, they are more or less widely distributed, and they seem to be fairly well adapted to that purpose. .

ROAD CONSTRUCTION

23

GRAVEL.-Gravel deposits are quite plentiful along the northern border of the Coastal Plain, where they are often seen in thick beds outcropping beneath the superficial layers of sand. The pebbles are all water-worn, and evidently mark the limit of an old shore line. They are often cemented by ferruginous, sandy clays, and make excellent material for road surfacing. Many exposures of these gravel deposits are to be seen in the vicinity of Augusta, Milledgeville, }.1:acon and Columbus. These- gravel deposits are well exposed just across the Savannah River from Augusta, near the Charleston and vVestern Carolina Railway. At this point, the gravel has been extensively worked for the last few years and shipped to Augusta, Savannah and other points, where it is used for both street and road surfacing. The binding material of this gravel is a ferruginous, sandy clay, which readily hardens into a compact mass on being dampened and rolled, forming an excellent road_ surface, which is both durable and free from dust.
CLAY.-The clays of the Coastal Plain and the other divisions of the State are quite abundant and are well suited for mixing sand-clay roads. At nearly all points through the Coastal Plain, such clays can be found from one to three feet below the surface.
ROAD CONSTRUCTION1
LocATION oF RoADs
The first thing to be considered in the location of a new road is the topography of the section through which the road is to pass. Where topographic maps are to be had, they can be used to great advantage in locating the most practical line for the proposed road. When these maps are not accessible,
1. For a more complete discussion of road construction see Bulletin No. 8, Roads and Road Materials of Georgia, published by this Survey..

24

PUBLIC ROADS OF GEORGIA

J



there must be a preliminary survey made, showing the loca-

tion and trend of the streams and ridges, together with the

relative positions of the ebjective points to be reached by the road. Having obtained this desired information, the road

bui1der proceeds to locate the line of road which will best
accommodate the traffic. for which lt is to be. eonstructed. The

easiest gr:;tdes and the shortest distances, consistent with the

cost of construction, together with conveniences and necessi-

ties of the eommunity, all should receive due consideration

. before the line of road is permanently located.

As a general rule, in mountainous or hilly countries, the

best and most important highways are- located along streams or ridges. Each of these locations has its advantages and disadvantages. Ridge roads are often dry and easily drained,,

but the descent of these roads to the valleys below are like-ly

to present difficult problems in securing practical grades.

The location of roads along valleys, on the qther hand, al-

though they may serve to a better advantage- a larger num-

ber of people, is frequently objectionable on account of the

extra expense of keeping up bridges. Even if the line of road

does not cross the main stream of the valley, there are always

,. many small tributaries or deep gorges to be bridged.

One of the most important questions to be solved by the

road builder in Georgia; is not so much the quet:ltion of loca-

tion of new roads as it is of changing the location of roads

already in existence. This is especially true where the roads

were originally laid out .along lot lines or division boundaries

between properties, regardless of grades and other condi-

tions. These mistakes mm;;t be corrected, in a great meas-:

ure, before it will be possible to construct :first-dass roads

with easy grade, throughout the State, at anything like a rea-

sonable cost. The road authorities of the several counties

should by all means see to it that their roads are always prop-

ROAD CCNSTRUCTION

25

erly located before attempting any permanent improvement. Such conditions as these practically prohibit the construction of good roads in many localities until they are re-located. Changing the location of established roads frequently presents a simple problem; but, at the same time, it may save hundreds of dollars per mile in the cost of grading.

GRADES

Grade, as used in highway construction, means the degree of inclination from the horizontal, or the slope of the road surface. The grade is usually expressed either in the form of a simple ratio, as, for example, 1:20, or terms of percentage. The ratio 1 :20 indicates a rise of 1 foot in every 20, or a 5 per cent. grade.
The grade of a road ,should depend, in a large measure, upon the character of the traffic for which the road is to be constructed. If the traffic is heavy and the individual loads
~
are large, it is always advisable to reduce the grade to the lowest possible minimum consistent with the cost of construction. Most road builders place the maximum grade of macadamized roads at 1:20. Such high grades as this, however, should be short, as they overstrain the team and render frequent stops necessary. The tractive force required to m.Qve a given load over a road with a grade of 1 to 30 is nearly three times as great as that required to move the same load over a level road. It is nearly always practicable to reduce the grade of a road to the above maximum limit, even in mountainous regions, by making the line of road sinuous or zig-zag, without greatly increasing the distance between the objective points or the cost of construction. A good example of a mountain road laid out on this plan is the newly constructed public highway extending from Dahlonega to Murrayville.

26

_ PUBLIC ROADS OF GEORGIA

Besides reducing the efficiency of tractive force, steep grades also greatly increase the cost of keeping roads in .repair. It is a well known law of running water, that its erosive power varies as the square of its velocity.; it therefore follows that a slight increase in grade will greatly increase the effective force of this destructive agent. The extra expense in maintaining a road with high grades will frequently aggregate, in a short time, a sum sufficient to pay the entire expense of relocating the road.
DRAINAGE
Drainage rs one of the most important questions which confronts the road builder. Unless a road is .properly drained, it is practically impossible to keep it in first-class condition..Water must be removed from the roadway or it will sooner or later destroy the hardened surface ap.d thus :ender the road imperfect. This is true, not only of common dirt roads, but also of macadamizred 'roads.
Road drainage is divided into two divisions, namely, surface drainage and subdrainage. surface drainage c-onducts the water which falls on the surface of.the road into the side ditches or drainways, while the subdrainage removes the water from beneath the surface.
Surface drainage rs accomplished by giving the surface of the roadway a slight inclination or slope from its center to its sides and is known as ':crowning" the road.
The angle of the slope which the crown of the road should have depends largely upon the character of the surfacing material used; that is, the angle of slope should be greater for permeable, such as ~andy clays, th::m for the more impermeable materials. The usual grade}or the crown of a macadamized road is about 1 in 30; that is, a roadway .30 feet in
Q
width should be six inches higher at the center than at the

ROAD CCNS1'P.VCTION

27

sides. The crown of a dirt road should be somewhat greater; but in no case should it be so great as to cause an undue lateral erosion of the surface from heavy rains. The water, as it flows from the surface of the roadway, should be received in properly constructed drains on either side of the road. These drains should have sufficient slope to conduct the wat8r off as rapidly as it accumulates.
A road propeTly crowned and supplied with suitable side ditches needs no further drainage. In some instances, however, subdrainage is also necessary to secure the proper drainage. The object of subdrainage is not only to remove the water which may penetrate the surface fr.om above, but also to draw off the water which, by lateral seepage, enters the roadbed from below. Subdrainage may be accomplished by the use of either side or central drains. Side drains may be open or closed, and should always have a depth of two feet or more below the surface of the roadway, and sufficient slope to carry off the water. Open drains perform the double office of carrying off both the surface and the underground waters; and, for this reason, they are often preferable to closed drains. These drains, however, on account of their depth and proximity to the roadway, are frequently dangerous and are therefore objectionable.
Closed drains are variously constructed. One of the simplest consists of a narrow, properly graded ditch, about two feet or more in depth, and partly filled with water-worn, rounded stones. In constructing a drain of this character, it is always advisable to place the largest stones on the bottom and the smallest on the top. Such an arrangement gives ample space at the bottom for the free circulation of the water and prevents the washing in of the earth from above. To guard more completely against the filling of the spaces between the stones by earth, it is often best to overlay them

. 28

PUBLIC ROADS OF GEORGIA

with grass or straw before :filling the upper part of the ditch with earth. Where stones are not to be had, a drain can be made of logs, poles, and brush, which will answer all practical purposes.
For a more detailed discussion of the question of subdrainage, including cost, etc., the reader is referred to Bulletin No. 8, on Roads and Road-Building Materials of Georgia, published by this Survey.
RoAD SuRFACEs
The. roadway having been properly graded and drained the next step is the preparation of the surface. This is accomplished by covering the roadbed to the depth of several inches with broken stones, or some other suitable material.
STONE.-When stone is used for .this purp<Jse, it is customary to prepare the roadbed by :first giving it the proper grade and crown, after which the roller is passed over it until the surface is thoroughly. consolidated and hardened. The surface, having been prepared as ab0ve described, is now ready to receive its covering of broken stones.
It is always bes.t to place the .broken stone on the prepared sub-grade surface in two or more layers, in order that it may
be more completely consolidated by traffic Ol! by the use of the roller. The total thickness of these layers should depend both on the character of the traffic for which the ):oad is constructed and, to some extent also, upon the nature of the road ~oundation. If the traffic is heavy and the individual loads are large, the thickness of the road-covering should be greater than when the opposite condit.ion.s exist. Furthermore, even when the traffic is light, the road-covering should be increased in thickness, wherever the foundation is unstable or insufficiently dr~ined. The road coverings vary from 4 to 12 inche~, an average, probably, being about sev.en inches.

EO..tlD CCNSTRVCTION

29

The first layer of stones should be spread as eyenly as possible over the prepared roadbed to the depth of three or four inches, and then thoroughly compacted by rolling. It is always desirable to have the stones as nearly cubical as possible; and, in no case, should they exceed two or thtee inches

in their greatest dimensions. The more cubical the stones, other things being equal, the easier they are to become con-

solidated into a compact mass.

The first layer of stone having been compressed from about six inches to four inches, it is ready for the reception

of the second layer. This layer of stone, in first-class roads,

is usually, when consolidated, about three inches in thickness,

and consists of fragments one and one-half inches and less,

.

.

.

in diameter. As the layer constitutes the actual wearing sur-

face of the road, it is essential that the stone used should be

as hard and tough as possible.

The road covering is finally completed by placing on the

surface a layer of binding material, one-half inch or more

in thickness, which is sprinkled and continuously rolled until it becomes thoroughly consolidated. One of the best and

most satisfactory materials to use as a binder is the chips and dust obtained by screening the broken stones.. When such

material is not at hand, small gravel, sand or loam will answer the purpose. The object of the thin superficial layer is to

form an impervious covering for the roadbed, and; at the same time, to unite the fragments of stone into a perfect

bond.

Having constructed the roadbed as above described, and given to its surface a sufficient crown to conduct the water

quickly into the gutters or side ditches, we have an excellent

country road, and one, if kept in proper repair, that will last for many years, even under heavy traffic. Such roads are

30

PUBLIC ROADS OF GEORGIA

but little affected by the seasons, and they are as serviceable for traffic in winter as in summer.

GRAVEL.-Instead of broken stone, gravel is often used for surfacing material. The gravel used for this purpose

may he either rounded or angular. The rounded pebbles are found in the greatest abundance along old coast lines or

occupying the beds of streams. The angular pebbles, on the

other hand, are the result of a peculiar disintegration of the

. parent rock, and frequently occur, in considerable beds mixed

more or less with clay. The water-worn pebbles are usually quartz, or some other hard rock well suited for wear on a

road surface. Intermingled with the rounded pebbles in the natural bed, is invariably to be found either sand or clay fill-

ing the int.erstices and forming a matrix, which binds the ma-

terials together. The value of a gravel as a road material

depends, in a large measure, upon the nature and physical

condition of the .matrix.

If the matrix consists of sand

.

.

alone, no amount of rolling or traffic will suffice .to compact

the material into a hardened road covertng; but if,. on the contrary, the matrix is made up of a sandy clay, with consid-

erable iron oxide, the. material is. readily consolidated and forms an excellent road surface. A fair idea of the binding

quality of the matrix of a gravel bed can usually be obtained

from an examination of the gravel pit. When the walls of the p:lt stand perpendicular for any length of time, without

signs of disintegration from freezing or other physical cause, the material will be found in most cases to give satisfactory

results on the roadway. Angular, or what is usually called pit gravel, binds read-

ily into a compact mass; and, on this account, it is commonly

. preferred to water-worn gravel. This kind of gravel always contains a considerable amount of clay, which should be separated from it by screening before it is put on the road. It is,

ROAD CCNSTRVCTION

31

furthermore, desirable, in order to obtain a uniform and smooth surface, to remove all the stones having a greater diameter than two inches. When it is not convenient to screen the gravel, the larger stones may be readily removed with a rake, as they are distributed over the surface of the road. . Before the gravel is placed in position, the roadbed should be properly prepared by giving it the necessary crown and by compacting its surface either by theQ roller or by traffic. The thickness of the gravel forming the road covering should be greater than that of broken stones. They should have a total thickness of eight or ten inches, and should be put on the prepared road surface in two or more layers, each layer being thoroughly rolled before the succeeding layer is placed in position.
One of the strongest arguments in favor of gra-vel roaus is the cheapness of construction. If the gravel has to be transported only a short distance, this kind of road covering is inexpensive, and at the same time forms a road surface well suited for country roads, where the amount of traffic is light.

SAND-CLAY RoAD.-A sand-clay road is a road surfaced with a mixture- of sand and clay in such a proportion that when the mixture is compacted it forms a firm surface suitable for traffic. Roads of this class have in the last few years attracted much attention throughout the Southern States by reason of their cheapness and suitableness for common country highways. The sand-clay mixture may be either aneartificial mixture or a natural mixture, but in either case, other things being equal, the relative proportions of the two different ingredients remain the same. It not infrequently happens that common earth roads have for long stretches the right proportioning of sand and clay to make a typical sand-

32

PUBLIC ROADS OF GEORGIA

clay road, in which case it is only necessary to give them the proper drainage and grade to form them into first-class sandclay roads. It must not be inferred from the above statement that any kind of clay 'is equally suitable for the con-struction of sand-clay roads. A. clay, in order to give the best results, should be highly plastic, and at the same time it should shrink but little in drying. In addition to tliese two
physical properties, the clay should also have good slaking
qualities, otherwise- it will form lumps and will not mix readily with the sand.
Many clays, espe?ially the high grade kaolins and fire clays, possess but little plasticity and as a result give very unsatisfactory results when used in constructing sand-clay roads. A. fair idea of the plasticity of a clay may be had by rolling out a small pencil of' it between the fingers and note the. degree to which it w~ll bend before breaking.
Shrinkage is the amount of contraction which a clay undergoes in the process of drying. The shrinkage of the Georgia clays, as shown by a large number of tests made in the Survey laboratory, varies- from 1 to 17 per ce:I?-t. Before using a clay for sand-clay :r;oads, it is always advisable to determine its shrinkage. This may be readily done by making the- clay into small bricklets and noting the degree of shrinkage upon drying. A. clay with a high shrinkage leads to cracking and breaking up of the surface during the process of drying and a corresponding expansion when again wet by rain, conditions highly detrimental to a good road surface.
The rate of slaking of a number of South Georgia's clays, together with the condition of the slaked product is shown by the following tal:>le:

ROAD CONSTRUCTION

,., 3i)

SLAKING TESTS OF GEORGIA 0LAYS1

Time Degree of slaking

Paper clay, Georgia Kaolin Co. . . . . . . . 6 Min. :fine powder

Paper clay, American Clay Co. . . . . . . . 3 min. :fine powder

Paper clay, Atlanta Mining &, Clay Co .. 5 min. :fine powder

Paper clay, Albion Kaolin Co. . . . . . . . . 4 min. :fine powder

Flint clay, Gibson . . . . . . . . . . . . . . . . . . .

no slaking

Paper clay, Butler ................... 4 min. pulverulent

Plastic white clay, Gibson ............ 5 min. :fiaky

W.hite clay, Perry ................... 2% min. lumpy

Fire clay, Copperas Bluff ............ 2112 min. coarse granules

Fire clay, Carr's Station ............ 7 min. :flaky

White, plastic clay, J. T. Hatfield ..... 7 min. granular

White clay, Rico mine . . . . . . . . . . . . . . . 4 min. complete

Pottery clay, I. Mandel .............. 10 min. slightly mealy

Fuller's earth, Twiggs county ........ 20 min. very :fine :flakes

\Vhite clay, Van Buren .............. 6 min. :fine powder
White clay, Carswell, Mcintyre ....... 3a min. slightly granular

\Vhite clay, Chalker . . . . . . . . . . . . . . . . . 5 min. coarse granules

White clay, B:y-ron .................. 5 min. coarse flakes

Terra cotta clay, Aragon.............

splits into coarse flakes, but

does not show complete dis

integration.

The above slaking tests were made by immersing oneinch cubes of clay, previously dried at a temperature of 212 degrees F., in 250 cubic centimeters of water. A slaking test of sufficient accuracy for road building clays may be made by dropping fragments of thoroughly dried clay into a glass of water and noting the rate and the degree of disintegration.
The relative proportion of sand and clay to be used in sand-clay roads may be determined by the following method as given by W. L. Spoon :1
''Two ordinary glass tumblers of the same size are filled to the brim, one with the dry sand to be tested and the other with water. The water is then pqured carefully from one glass into the sand in the other until it reaches the point of overflowing. The volume of water removed from the glass which was originally full of water can be taken as an ap-
1. For a more complete discussion of the physical properties of the Georgia clays, see the Report on the Clay Deposits of Georgia issued by this \:\urvey.
1. Farmer's Bulletin No. 311, U. S. Department of Agriculture, page 10.

34

PUBLIC lW.ADS OF GEORGIA

proximate measure of the VQids in the unit volume of sand

contained in the tumbler. A simple calculation will reduce

this to percentage volume."

(j

These. various tests are only given to enable the road constructor in the beginning to get a rough idea of the material to be used in constructing his sand-clay surface-. By making these simple tests and also by a critical study of the- mixture in a natural sand-clay road, in a short time, the road builder learns to select the material with a fair degree of accuracy without the use of tests.

The methods of building sand-clay roads are variable, depending upon the character of the subsoil and the nature of the material to be used: In the case the subsoil consists of sand, the method of surfacing, after the roadway has been properly drained and graded, is to cover the roadbed with a l~yer of clay from six to eight inches in thickness in the center, thinning gradually to the- outer edge to :five inches or less. g As each load of clay is dumped ~:m the road it s.hould be S!)rea:d uniformly over the surface . to the desired thickness. The surface is now ready for its coating of sand, which should be spread evenly over the surface. Where the clay is not too lumpy, the sand may be allowed to be worked into the clay by traffic, more being added from time to time as it is needed. This method of making a sand-clay r?ad is quite slow, unless the materials are espec1ally adapted for the purpose for which they are used. To hasten the pr.Qcess of mixing the sand and ?lay, often the harrow ana the plow are resorted to. Where this is done, it is best to use the plow and harrow just after a rain, when the surface of the road is in such a condition that it readily works up into a thin mud.

In case the subsoil is clay, the road is :first drained, graded and crowned, as before, when the- surface is loosened up and

ROAD CONSTRUCTION

35

pulverized by the plow and the harrow to a depth of about four

inches. It is then covered to a depth of six or seven inches

with sand, after which the sand and clay are mixed dry by har-

rowing. To get the best results, the road surface should be

again mixed and puddled after a rain and then given the

proper crown by a road machine or a' drag.

These methods are usually employed when the sand-clay

road surcface is an artificial mixture, but when the sand-clay

is a natural mixture the method is somewhat different. The

method of constructing sand-clay roads with a natural sand-

clay mixture, as adopted in Clarke county, and described by

Prof. C. M. Strahan1 in the Engineering Annual of the Uni-

versity of Georgia, is here given:

"First. The grading of the road bed is first done to a

width of 30 feet.

'' flecond. In the center a bed of top soil 10 inches deep

and 16 feet wide is laid. The teams haul over this bed as the

work progresses. With clay foundation, it would be a mis-

take to prepare a trench to receive the top soil.

"Third. The road machine excavates flat-side ditches six

inches deep and four feet wide; throwing the earth as a shoul-

der against the top soil bed, and then crowning the whole from

ditch to ditch.

''Fourth. The construction teams and traffic pass over

the green bed and pack it down chiefly in the center. When

several hundred yards are thus partially packed, the road

machine pulls in the material from the sides and resurfaces

the bed. New top soil is delivered for weak place_s and

/'.

shaped up.

''Fifth. As fast as the grading of the bed is finished, the

1. Engineering Annual, University of Georgia, Vol. IX, No. lOa, June, 1909, pp. 18-19.

3G

PUBLIC ROADS OF GEORGIA

top soil layer "is spread on it.. Thus by the time one-half mile

of road has been graded and covered with top soil, the first

one-fourth mile has undergone considerable packing and re-

surfacing and getting into good shape.

''Sixth. For some- weeks close attention is paid to the new

bed, watching for weak places, doctoring them, maintaining

the grade with new top soil and keeping the 'crown fully up
., to one inch per foot.

''Seventh. ,Wet weather hastens the period of consolida-

tion if followed by a dry spell. When .packed quite wet, the

wheels consolidate the material from the bottom upward. In

dry or moist weather, the top layer only is consolidated and

may cut through at the next rain. A period of wet weather is usually necessar' y for a full packing down of the top soil

into permanent firmness.

"Eight}+. Usually; in two months, a new top soil road-

bed is cop.s9lidated, shaped to its correct crown, and able

the:reafter to withstand the rains and the traffic. Much .-ef the

reshaping aud doctoring of the surfac.e coat -is done at odd

ti:mes incidental to the- main grading work while the teams are

in transit from barracks to the work.''

The cost per mile to Clarke county of putting on this ''top

soil" coat, according to Prof. Strahan's estimate, using convict

labor at 50 cents per day and the county teams at $1.00 per

day, is $400.00.

The material which is used for road surfacing in Clarke

county, designated as "top soil," is a residual sandy clay,

tesulting from. the. weathering o.f granites and granite-like

... .

rocks.. It usually contains. 50 per cent. or more of hard;

coarse residue, consisting of quartz and feldspar, the latter

often partially altered into kaolin. Experience shows that

the best ''top soil'' is found in cultivated fields where the

fine particles of mica are wanting and the clay has the essen-

37
tial plasticity. The results which have been obtained in Clarke county with the natural sand-clay mixture are very satisfactory, and the work fully demonstrates what can be done throughout the Crystalline Area region of Georgia where like material for building sand-clay roads is abundant.
A somewhat different material from the above natuTal sand-clay mixture has recently been extensively used in road construction in Sumter and other counties in South Georgia. The material here referred to is a reddish sandy clay widely distributed throughout the Coastal Plain. It, like the clays of the Crystalline Area, is often partially residual, having resulted from the weathering of the underlying formations. In Sumter county excellent results have been obtained by using the clay directly from the roadway without any previous mix-
ture. The only attention necessary to keep these roads in
first clatils condition, after they have been once properly graded and drained, is an occasional use of the split log drag, which fills up all ruts and washes and at the same time restores the former crown and leaves the surfa~e in a smooth, even condition. These roads, which I had the pleasure of examining a few weeks ago, are what may be termed ideal
country roads, over which from 8 to 10 bales of cotton may
be drawn by a two-horse team with comparative ease. Such roads as those here referred to, namely, 1wads constructed of natural sand-clay mixture, may be found in a large number of other counties of South Georgia. In many places throughout this part of the State, it is true, surface sands occur, in which case artificial sand-clay mixtures must be resorted to, but, fortunately, even here only a few inches, or at most a foot or so, beneath the surface sands generally occurs an abundance of clay suitable for sand-clay mixtures.

BULLETINS OF THE GEOLOGICAL SURVEY

OF GEORGfA.

.. . : . ..

. .

.. '\

1. Marbles of Georgia, by S. W~ McCallie, 1894, 87 pp., 16 pl., and 2 maps.

Out of print.

,

1. ' 1\fri~;p_les of Q-eo;rgiq,. Second Edition, Revised and Enla:uged, by S. \V.

. McCallie, ~~07., 126 pp., 52. p~., and 2 J?aps. Postage, 13 ce1its.

2.' Corundum Deposits of Georgia, by Franci~ P. King, 1894, 133 pp., G pl.,

,. '" 1 niap. Postage, 9 cents. .

"

-3. A P~"Jrt of the vy'.ater.-Powers of Georgia, .by C. C. Anderson and )3. M.
Hall, 189G,;:,~~R:.PP, 10 pl., and 2 map$. Postage, 9 cents. ' .

4. A Part of tl1eno:fd~Deposits of Georgia, by W. S. Yeates, S; W; Me-

. Callie apd ifr~ancis P. :King, 1896, 542 PP; 21 pl.1 and 1 map~ Out

af p~jnJ..

.

.

5. A Part 6 .ithe Phosphates and Marls of Georgia, by S. W. McCallie,

~~9.G;.~9tLpp.: 3 pl. Postage, 7 cents.

6, A Pa,rt of t~e. Clays of Georgi!;l, by Geo. ;EJ. L~;tdd,. ~898, 204. pp.,, 17 pl.

. Postag?; l1 ceizts. ,.

.

. .

1-. ArteSiai1~Well Systeri:fof Georgia, byS.: W. McCallie;' 18~8, 214 'l~p., 7

.

,<

.ttP,:.'31: pl.:, 8. Roads

a,n.d 3:1?-.4.

?\.i:inHPS '/I}ostage 13 cents, Ro~aq.,~Uilding .Materials of

. Ge?rgia,

by

. S.

. W.

. McCallie,

ir'':!f9'01; 26:4'pp:; '.27.p1., and 1 map. Postage, 14 cent's.

... '

.9; :A.,J?,.a~:tJ~~~~~J~:i'a;l).it~s~a:nd Gneisses of Georgia, by Thomas.L; Wa.tso11,

, 190;.2, 3.6,7.,,jp.p.,...32 pl., and 4 ma,ps.. ,Post(tge,JJ1 eents.

. .

1_0.. Ircni Oves';rdf'::'P.Olk, .Barterw arid .Flciyd Counties, Georgia, by S. W. Me-

lp...,.,..,~~'J,~Citae:l:l~ieh>'>1Q.9sQit'Os.;i.l.!,.f).).t..O-u~'pGeppf.,gi8?;,plb.~y

l'map. -Pos'tttge 11 cents.
W T~os, .~,-, ~tson, 19;0-;1,,_)69.

pp.,

: 12. p-1.,

...

.. i and ..lmap,. :P,o.f'~a9,'13c10 cents.

.

.

12: .. c~~lDep_o.sits 6 G~orgi~.1 :PYi-S; W. McCallie, i904, 121.pp.'; 14 pl., anti

~ ; .a_ ~map:: Ed~taiy,e !)':~'C.e?itR:.;;: . _.,. : : :,

.. . ..

1:3. "

_,.Qcb3er!,.pDa.pepso. sitsJ?_oofst~a._Q'.g~~-q~r,'gti/'ac~e,~,ib',j.~',':~r,b.g"~,'.

L.'

W.atsoq,

lQOQ,

81

pp.1

ll

pL~ .,

a.pcl

14. 'Manganese Deposits of Georgia, ~l:i~'I~b,bma:s L. \Vatson;. ill908, 195 pp:.,

: . ._8 pl.; _;and '2 map~. -f,o~tag~..J2 ~~??:t'L .

. ,

13. Uncler~Tound waters of Georgi3:; b~( 1S'l''\-V. McCallie, 1908, 376 pp., 29

. pl:,. and'2-~'aps. Post~ge 2o c.~'J'I,tS.,"f1f'

. .

.

:16. .water..:Powers af Georgia, by: B. M. 'ari'if"M, R.. Ha:ll, 1908, 424 pp.,-.14

.: '., .. p.L, .an.d-1 illllP Posta,ge 21 oill'ts.

.. . . .

17. F_ossit IrolJ. 'Oi~e 'Deposit.s o~ Georgia, by S. W. McCallie, 1908; 199 pp.,

.; ..: '24. pL, and S maps. . Postq,ge 14 cents.

.

.

],.$~,. G~~Y. Deposits of Q:em~gia, by Qtto Veatch, 1909, 453 pp., 32 pl., :and ;3

' map.s. Postage 25 cents.

.



1~). Qold D.eposits of Georgia, by S. P. Jones, 19091283 pp., 8 pT.; and 2

, , : maps. Post-gg;e 16 .cents. .



20.. ]'\f~_n&r;:\1 Wate:J:;S pf Georgia, by_ S. 'fV.. MGCallie.. In .prep,qra.tion~

21. i-M.~r]s and Limestones of Georgia, by Otto Veatch. In preparation.
22. :m:own Iron Gre$ of Gedrgia, by S. W. McCalli:e. In p1ep.arat.ion:

23~ Mineral. Resot\rces of Georg}a, by S. \V, -McCallie, 1910, 208 pp., 20. pl.,

''

24.

and 2 maps. Postage 14 cents.



Public R.oads of Georgia, Second Report, by S. vV. McCallie, 1910, 3G

pages. Postage 5 cents.

,
NQ~Jj:.-For bound copies of Bulletins Nos. 1, Revised, and 6 to 23, inclnsiYe, 3 cents additional postage will be required.