134 
FLORIDA GEOLOGICAL SURVEY— 15 TH ANNUAL REPORT 
Fire tests: 
T emperature. 
Linear Shr. 
Per Cent. 
Absorption. 
Per Cent. 
Porosity. 
Per Cent. 
Color. 
950°C. 
0.6 
15.18 
33.60 
Cream. 
1050 
1.1 
15.22 
34.20 
Cream. 
1150 
1.6 
14.50 
33.60 
Cream. 
Another brick plant was formerly operated about one-half mile 
north of Lake City where a sandy surface clay was used which likewise 
is undesirable for any burned product except a very low grade of com¬ 
mon brick. 
A bluish-gray clay occurs on the property of W. N. Cone about four 
miles north of Lake City on the Benton Road. Its plasticity is fair, its 
air shrinkage high, and its general qualities poor. It has, however, a 
high modulus of rupture, but is nevertheless undesirable for burned 
products. It has the following physical properties: 
Physical Properties of IV. N. Cone Clay (Lab. No. 0 - 15 ). 
Plasticity, judged by feel. Fair. 
Water of plasticity . 41.20% 
Linear air shrinkage. 14.7 % 
Volume air shrinkage. 46.2 % 
Modulus of rupture, average. 1075.3 pounds per square inch. 
Slaking test. 15 minutes. 
Steel hard at cone 010. 
Overfires at cone 1. 
Fire tests: 
Temperature. 
Linear Shr. 
Per Cent. 
Absorption. 
Per Cent. 
Porosity. 
Per Cent. 
Color. 
950°C. 
6.3 
5.54 
25.75 
Brick red. 
1050 
7.8 
4.80 
24.25 
Brick red. 
1150 
8.3 
3.58 
22.25 
Brick red. 
DADE COUNTY 
Dade County is situated in the extreme southern portion of the 
State and its surface formations consist of limestones, sands and marls. 
No clays of importance are known. 
DE SOTO COUNTY 
De Soto County lies in the south central portion of the peninsula. 
The surface materials consist of sands, marls and sandy clays. Good 
sand-clay road material is abundant in the northern part of the county. 
A white clay high in lime and magnesia occurs a few miles northwest of 
Arcadia and extends northwestward through Manatee County to the 
vicinity of Bradentown. Its lime content gives it a short firing range 
