214 
FLORIDA GEOLOGICAL SURVEY—I5TH ANNUAL REPORT 
WASHINGTON COUNTY 
Washington County lies in west Florida and is bordered on the 
west by the Choctawhatchee River. It is underlain by the Chatta¬ 
hoochee, Alum Bluff, Choctawhatchee and Pleistocene formations. 
The only clay of any value found in the county is a flood-plain de¬ 
posit about two miles southwest of Chipley, which deposit is being 
worked by the Hall Brick Company for common brick. The nearest 
railway is two miles and practically all of the product is sold locally. 
The deposit has been proven on about sixty acres and probably 
underlies a more extensive area. The clay stratum is about three feet 
in thickness, is overlain by six inches of soil and underlain by sand. The 
raw clay is black, fairly plastic and has good working qualities. It is 
cream-burning at the lower temperatures and changes to gray at about 
cone 1. 
This clay is suitable in its present state for common structural ma¬ 
terials such as face and common brick, hollow-block ware, drain tile, etc. 
It contains a small amount of coarse quartz sand and if this is washed 
out the clay may be used for stoneware, flower pots, turpentine cups, and 
similar articles. It has the following physical properties: 
Physical Properties of Hall Brick Company Clay (Lab. No. 0 - 7 ). 
Excellent. 
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 1. 
28.80% 
1.13% 
27.67% 
9.00% 
27.55% 
135.4 pounds per square inch. 
20 hours. 
Fire tests: 
Temperature. 
Linear Shr. 
Per Cent. 
Absorption. 
Per Cent. 
Porosity. 
Per Cent. 
Color. 
950°C. 
2.0 
21.75 
30.80 
Cream. 
1050 
2.5 
20.10 
30.50 
Cream. 
1150 
5.0 
11.90 
26.40 
Gray. 
1190 
6.0 
9.30 
21.50 
Gray. 
1230 
8.0 
6.10 
21.02 
Gray. 
1310 
4.80 
13.10 
Gray. 
1370 
3.84 
12.75 
Gray. 
1430 
12.0 
2.59 
8.55 
Gray. 
