A PRELIMINARY REPORT ON CLAYS OF FLORIDA 195


buff-colored product at cones 010 and 05, and burns to a more dense texture and reddish color at cone 1. It fuses at cone 5.
 Several samples of the Bartow clay were examined. These indicate that it is very uniform in its physical properties. The following sample taken from one of the phosphate mines near Bartow has the following physical properties:

 Physical Properties of the Bartow Clay (Lab. No. o-53).
 Plasticity, judged by feel........... Fair.
 W ater of plasticity................. .20.10%
 Pore water ........................ 0.00%
 Shrinkage water .................. 20.10%
 Linear air shrinkage............... 5.00%
 Volume air shrinkage.............. 11.20%
 Modulus of rupture, average........ 195.3 pounds per square inch.
 Slaking test ....................... 24 hours.
 Steel hard at cone 3.
 Overfires at cone 5.

 Fire tests:
Temperature. Linear Shr. Absorption. Porosity. Color.
 Per Cent. Per Cent. Per Cent,
 950'C. 0.00 18.57 37.10 Buff.
 1050 0.00 16.38 36.00 Buff.
 1150 0.00 12.84 31.20 Gray.
 1190 3.00 10.60 27.00 Gray.
 1230 3.00 Gray.

 Numerous lacustrine deposits are found throughout the eastern part of the county. These deposits are usually local and of limited extent.
 In the eastern part of the county is a well-defined, irregular ridge, extending from Haines City southward beyond Frostproof. Immediately west of this ridge are several thin sedimentary clays. These strata frequently have considerable areal extent, but they are too thin to warrant commercial exploitation. A section made on the Highlands Farms, four miles north of Lake Wales, which will serve as an example, is as follows:

 Section Made in Clay-Bearing Strata on Highland Farms, Lake Wales.
 Feet. Inches.
 Sand .................................................... 3
 Clay, gray, sandy ........................................ 1
 C lay, grayish red ........................................1
 Clay, gray, sandy ....................................... 1
 C lay, gray, jointed ....................................... 1 6
 Sand, red ............................................... ?