A PRELIMINARY REPORT ON CLAYS OE ELORIDA 
183 
Physical Properties of Estijfanulga Bluff Bottom Clay (No. 0-4.6). 
Plasticity, judged by feel. Excellent. . 
Water of plasticity. 29.45% 
Pore water .. 0.45% 
Shrinkage water . 29.00% 
Linear air shrinkage. 8.30% 
Volume air shrinkage. 31.05% 
Modulus of rupture, average. 570.9 pounds per square inch. 
Slaking test. 24 hours. 
Steel hard at cone 05. 
Fire tests: 
Temperature. 
Linear Shr. 
Per Cent. 
A bsorption. 
Per Cent. 
Porosity. 
Per Cent. 
Color. 
950°C. 
2.7 
19.71 
35.60 
Cream. 
1050 
3.2 
19.87 
36.00 
Cream. 
1150 
6.7 
11.61 
25.20 
Cream. 
1190 
6.7 
9.05 
19.30 
Cream. 
1230 
6.7 
7.10 
15.80 
Cream. 
1310 
6.7 
4.53 
10.60 
Cream. 
1370 
7.2 
2.52 
6.70 
Gray. 
1430 
8.2 
1.29 
3.65 
Gray. 
MADISON COUNTY 
Madison County lies in north Florida between the Suwannee and 
Aucilla rivers. It is underlain by the Alum Bluff and Chattahoochee 
formations. A mantle of red, sandy clay covers practically all of the 
county, but no clays suitable for manufacturing purposes are known. 
manatee county 
Manatee County is situated south of Tampa Bay on the west side 
of the peninsula. Its surface exposures are chiefly the Alum Bluff 
and Bone Valley formations. 
The H. A. Graack and Sons Pottery in Bradentown uses a sandy 
clay dredged from the Manatee River. The clay is washed by hand 
before using. 
A white, calcareous clay occurs east of Bradentown and occupies a 
more or less continuous area eastward to the vicinity of Gardner and 
Arcadia. An exposure on the property of W. J. McLaughlin, eight and 
one-half miles east of Bradentown, Sec. 28, Twp. 34 S., R. 19 E., shows 
the following section: 
Section Exposed in Creek near Sawmill on IV. J. McLaughlin Property. 
Feet. Inches. 
Soil ... 18 
Clay, white (Lab. Sample No. 0-72). 4 6 
Clay, white (Lab. Sample No. 0-19). 24 plus 
