162 
FLORIDA GEOLOGICAL SURVEY- 15 TH ANNUAL REPORT 
This clay may be used to make an excellent grade of common build¬ 
ing brick and similar structural materials. Rail transportation is not 
nearer than about three miles, but the Apalachicola River offers water 
transportation to points down that river and up the Flint and Chatta¬ 
hoochee Rivers in Georgia and Alabama. This clay has the following 
physical properties: 
Physical Properties of State Hospital River Field (Lab. No. 0-8). 
Plasticity, judged by feel.... 
Water of plasticity. 
Pore water. 
Shrinkage water. 
Linear air shrinkage. 
Volume air shrinkage. 
Modulus of rupture, average 
Slaking test. 
Steel hard at cone 9. 
Excellent. 
26.50% 
0.94% 
25.56% 
8.1 % 
23.6 % 
301.1 pounds per square inch. 
36 hours. 
Fire tests: 
T emperature. 
Linear Shr. 
Per Cent. 
Absorption. 
Per Cent. 
Porosity. 
Per Cent. 
Color. 
950°C. 
0.9 
17.95 
39.02 
Brick red. 
1050 
1.1 
20.50 
39.40 
Brick red. 
1150 
1.9 
16.45 
39.40 
Brick red. 
1190 
4.4 
13.15 
38.50 
Brick red. 
1230 
4.9 
12.70 
31.20 
Brick red. 
1310 
4.9 
8.35 
31.60 
Brick red. 
1370 
5.4 
3.29 
25.50 
Brick red. 
1430 
7.9 
14.90 
Brick red. 
The Ocklocknee Brick Company, located on the Seaboard Air Line 
Railway at Lawrence, uses a flood-plain clay. The deposit is five 
feet thick and is overlain by six inches of soil. The clay has good plastic¬ 
ity and bonding strength and presents no drying difficulties. It is now 
used in the manufacture of common brick. An excellent grade of com¬ 
mon brick, hollow-block ware, and drain tile may be made from it. A 
series of compression tests made on the Ocklocknee Brick Company’s 
product by the Birmingham branch of the Pittsburgh Testing Laboratory 
were as follows: 
Compression Tests on Ocklocknee Brick. 
IVeight 
Pounds. 
No. 1—4.1 
No. 2—4.1 
No. 3—4.2 
Dimen¬ 
sions. 
3.6x7.8 
3.7x7.7 
3.7x7.8 
HARD BRICK. 
Area, square 
inches. 
28.08 
28.49 
28.86 
Load, 
pounds. 
78,900 
83,600 
88,500 
Unit load, pounds 
per square inch. 
2,810 
2,935 
3,067 
Average 
2,937 
