164 
FLORIDA GEOLOGICAL SURVEY—I5TH ANNUAL REPORT 
The Tallahassee Pressed Brick Company, Havana, located farther 
up the Ocklocknee River, also utilizes a flood-plain clay having properties 
very similar to the clay previously described. This plant is located on 
the Georgia, Florida and Alabama Railroad. The deposit is about five 
feet thick, overlain by about six inches of soil, and has been proven on 
about sixty acres. It probably, underlies a more extensive area. 
This clay has excellent working qualities. A good grade of com¬ 
mon building brick, fireproofing, hollow blocks, or drain tile may be 
made from it. Its physical properties are: 
Physical Properties of the Tallahassee Pressed Brick Company Clay (Lab. No. 0-17). 
Plasticity, judged by feel 
Water of plasticity. 
Linear air shrinkage. .. . 
Volume air shrinkage. . . 
Excellent. 
25.65% 
10.3 % 
27.8 % 
Modulus of rupture, average. 
Slaking test. 
Steel hard at cone 010. 
498.4 pounds per square inch. 
48 hours. 
Fire tests: 
Temperature. 
Linear Shr. 
Per Cent. 
Absorption. 
Per Cent. 
Porosity. 
Per Cent. 
Color. 
950°C. 
0.3 
17.32 
33.00 
Brick red. 
1050 
0.3 
16.80 
32.45 
Brick Red. 
1150 
0.7 
14.20 
30.25 
Brick Red. 
1190 
0.7 
11.42 
25.50 
Brick Red. 
1230 
1.2 
11.05 
29.20 
Brick Red. 
1310 
1.8 
10.90 
23.75 
Brick red. 
1370 
2.2 
10.18 
20.20 
Brown. 
1430 
2.2 
9.30 
14.20 
Brown. 
The two plants located on the Ocklocknee River supply a demand 
for brick throughout northwestern Florida and southern Georgia. 
GLADES COUNTY 
Glades County borders Lake Okeechobee on the west and is under¬ 
lain chiefly by sands and marls in which exposures are rare. No clays 
of importance are known. 
HAMILTON COUNTY 
Hamilton County is located in north Florida between the Suwannee 
and Withlacoochee rivers. The surface materials are chiefly Chatta¬ 
hoochee, Alum Bluff and Recent formations, in which surface, sandy 
clays, in places containing some gravel, are common. 
