A PRELIMINARY REPORT ON CLAYS OF FLORIDA 
165 
At the bridge across the Suwannee River at White Springs an eight- 
foot bed of a green-colored, plastic, jointed clay, overlain by six feet of 
soil, is exposed. This clay has a high air shrinkage and warps and 
cracks badly in drying and burning. It therefore is of no value in the 
manufacture of burned clay products. 
An exposure of a soft, white shale or partially consolidated clay 
occurs on the west bank of the Suwannee River about five miles north¬ 
east of White Springs. Only one exposure of this clay was seen in this 
vicinity, but it probably underlies a considerable area on both sides of 
the river. The deposit is overlain by a sand ranging from six to ten feet 
in thickness. A twenty-two-foot thickness of clay is exposed above the 
river level. Its depth below the river is not known. 
This clay has excellent plasticity and working qualities and dries 
without difficulty. Its high air and fire shrinkage are detrimental and 
this, in connection with a slight tendency to warp in firing, renders it 
useless for burned products. The clay vitrifies at cone 3 and becomes 
distinctly porous at cone 5. Its physical properties are: 
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 010. 
12.80% 
39.70% 
14.3 % 
42.8 % 
470.8 pounds per square inch. 
24 hours. 
Physical Properties of White Springs White Shale (Lab. No. o~g). 
Excellent. 
52.50% 
Fire tests: 
Temperature. Linear Shr. Absorption. Porosity. Color. 
Per Cent. 
Per Cent. 
Per Cent. 
950°C. 
8.2 
32.20 
52.63 
Cream. 
1050 
5.7 
30.51 
46.02 
Cream. 
1150 
15.7 
17.02 
31.82 
Light yellow. 
1190 
16.7 
1.33 
5.72 
Light yellow. 
1230 
14.7 
0.78 
2.97 
Light yellow. 
HARDEE COUNTY 
Hardee County is situated in south Florida and is underlain by the 
Bone Valley and Caloosahatchee formations. The Bartow Clay is found 
extensively throughout the central and western parts of the county. (For 
discussion on the Bartow Clay see Polk County, page 195.) A coarse, 
reddish to brownish, sandy clay is exposed near Bowling Green, Zolfo 
