A PRELIMINARY report ON CLAYS OE FLORIDA 
131 
The Clay County Steam Brick Company’s plant located in the north 
edge of Green Cove Springs, works a deposit of gray and red mottled, 
plastic, slightly sandy clay, the presence of which has been proven under 
about thirty-five acres and probably underlies an even larger area. It 
varies from six to ten feet in thickness, has an overburden of loose sand 
and soil, and overlies a clean, white, sharp sand. The sand underlying 
the clay is used in cement and concrete construction work in Green Cove 
Springs. This clay is desirable for common brick and drain tile. A sam¬ 
ple taken from the pit face as worked has the following physical proper¬ 
ties : 
Physical properties of the Clay County Steam Brick Company’s Clay (Lab. No. 0 - 4 . 3 ). 
Plasticity, judged by feel. Excellent. 
Water of plasticity. 25.75% 
Linear air shrinkage. 10.02% 
Volume air shrinkage. 31.55% 
Modulus of rupture, average. 513.2 pounds per square inch. 
Slaking test.. 1 hour. 
Fire tests: 
Temperature. Linear Shr. Absorption. Porosity. Color. 
Per Cent. Per Cent. Per Cent. 
950°C. 0.2 13.32 30.95 Grayish pink. 
1050 0.2 14.31 31.50 Gray. 
1150 0.2 11.89 28.50 Gray. 
1190 0.3 11.96 28.45 Gray. 
1230 0.8 11.06 22.75 Gray. 
1310 0.8 11.03 20.50 Gray. 
A clay collected by Mr. George T. Lloyd, from SEJ4 Sec. 11, T. 
7 S., R. 24 E., is suitable for soft, porous, common brick. Its physical 
properties are: 
Physical Properties of Lloyd Red.Burning Clay (Lab. No. 0 - 64 ). 
Plasticity, judged by feel. 
Water of plasticity . 
Pore water. 
Shrinkage water. 
Linear air shrinkage. 
Volume air shrinkage. 
Modulus of rupture, average. 
Excellent. 
24.20% 
1.07% 
23.13% 
10.00% 
30.20% 
565.4 pounds per 
square inch. 
Slaking test 
Fire tests: 
nPerature. 
Linear Shr. 
Absorption. 
1 hour. 
Porosity. 
Color. 
950°C. 
Per Cent. 
0.0 
Per Cent. 
14.01 
Per Cent. 
33.00 
Light brick red. 
1050 
0.5 
15.03 
32.50 
Light brick red. 
1150 
1.0 
11.72 
28.75 
Light brick red. 
1190 
1.0 
11.21 
28.20 
Brown. 
1230 
1.5 
10.60 
25.10 
Gray. 
1310 
2.5 
10.50 
29.50 
Gray. 
