A PRELIMINARY REPORT ON CLAYS OE ELORIDA 
209 
is now removed in order to obtain the underlying marl for road purposes, 
this clay might be of some value as a by-product. 
This mixture has excellent drying and working qualities, is red- 
burning, and would be suitable for a good grade of structural materials. 
The shells associated with these two clays are detrimental and would 
necessarily have to be removed or very finely ground. The physical 
properties are: 
Physical Properties of DeLand City Clay (Lab. No. 0 - 48 ). 
Plasticity, judged by feel. Excellent. 
Water of plasticity... 29.90% 
Pore water . 6.12% 
Shrinkage water .. 23.78% 
Linear air shrinkage. 13.0 % 
Volume air shrinkage. 38.0 % 
Modulus of rupture, average. 966.5 pounds per square inch. 
Slaking test... 30 minutes. 
Steel hard at cone 010. 
Fire tests: 
Temperature. Linear Shr. Absorption. Porosity. Color. 
Per Cent. 
Per Cent. 
Per Cent. 
950°C. 
1.0 
11.40 
27.9 S 
Brick red. 
1050 
2.0 
9.72 
25.95 
Brick red. 
1150 
2.0 
9.96 
25.20 
Brick red. 
1190 
1.0 
7.49 
21.20 
Brick red. 
1230 
0.5 
12.51 
26.75 
Brick red. 
A sandy clay, occurring in the northwest part of the city of De- 
Land, was formerly worked for common brick. The deposit consists of 
three feet of sand, three feet of red-mottled clay, and three feet of a buff 
clay, underlain by a sand. 
This clay may be used for a porous, common brick. The physical 
properties are: 
Physical Properties of Herman Brown Brick Yard Clay (Lab. No. 0 - 35 ). 
Plasticity, judged by feel. . Excellent. 
Water of plasticity.. 26.70% 
Pore water .. 0.00% 
Shrinkage water .. 26.70% 
Linear air shrinkage. 10.7 % 
Volume air shrinkage...... 27.75% 
Modulus of rupture, average. ....... 306.4 pounds per square inch. 
Slaking test .. 10 minutes. 
