A PRELIMINARY REPORT ON CLAYS OF FLORIDA 183

 Physical Properties of Estiffanulga Bluff Bottom Clay (No. o-46).
 Plasticity, judged by feel........... .Excellent.
 W ater 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. Absorption. Porosity. Color.
 Per Cent. Per Cent. Per Cent.
 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 Satwmill on W. 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