134 FLORIDA GEOLOGICAL SURVEY-15TH ANNUAL REPORT

 Fire tests:
 Temperature. Linear Shr. Absorption. Porosity. Color.
 Per Cent. Per Cent. Per Cent.
 950*C. 0.6 15.18 33.60 Cream.
 1050 1.1 15.22 34.20 Cream.
 1150 1.6 14.50 33.60 Cream.

 Another brick plant was formerly operated about one-half mile north of Lake City where a sandy surface clay was used which likewise is undesirable for any burned product except a very low grade of common brick.
 A bluish-gray clay occurs on the property of W. N. Cone about four miles north of Lake City on the Benton Road. Its plasticity is fair, its air shrinkage high, and its general qualities poor. It has, however, a high modulus of rupture, but is nevertheless undesirable for burned products. It has the following physical properties:
 Physical Properties of W. N. Cone Clay (Lab. No. o-i5).
 Plasticity, judged by feel............ Fair.
 W ater of plasticity ................ 41.20%
 Linear air shrinkage................. 14.7 %
 Volume air shrinkage............... 46.2 %
 Modulus of rupture, average........ 1075.3 pounds per square inch.
 Slaking test ....................... 15 minutes.
 Steel hard at cone 010.
 Overfires at cone 1.
 Fire tests:
Temperature. Linear Shr. Absorption. Porosity. Color.
 Per Cent. Per Cent. Per Cent.
 950*C. 6.3 5.54 25.75 Brick red.
 1050 7.8 4.90 24.25 Brick red.
 1150 8.3 3.58 22.25 Brick red.

 DADE COUNTY
 Dade County is situated in the extreme southern portion of the State and its surface formations consist of limestones, sands and marls. No clays of importance are known.


 DE SOTO COUNTY
 De Soto County lies in the south central portion of the peninsula. The surface materials consist of.sands, marls and sandy clays. Good sand-clay road material is abundant in the northern part of the county. A white clay high in lime and magnesia occurs a few miles northwest of Arcadia and extends northwestward through Manatee County to the vicinity of Bradentown. Its lime content gives it-a short firing range