A PRELIMINARY REPORT ON CLAYS OV VLORIDA 165

 At the bridge across the Suwannee River at White Springs an eightfoot 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 northeast 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:
 Physical Properties of White Springs White Shale (Lab. No. o-3).
 Plasticity,- judged by feel............ Excellent.
 W ater of plasticity................. 52.50%
 Pore water ........................12.80%
 Shrinkage water ................... 39.70%
 Linear air shrinkage................ 14.3 %
 Volume air shrinkage............... 42.8 %
 Modulus of rupture, average........ 470.8 pounds per square inch.
 Slaking test ....................... 24 hours.
 Steel hard at cone 010.
 Fire tests:
Temperature. Linear Shr. Absorption. Porosity. Color.
 Per Cent. Per Cent. Per Cent.
 9500C. 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