A PRELIMINARY REPORT ON CLAYS Or FLORIDA 159

 Physical Properties of State Hospital Road Clay (Lab. No. 0-79).
 Plasticity, judged by feel............ -Poor.
 W ater of plasticity................. 32.25%
 Pore water ........................ 5.40%
 Shrinkage water ................... 29.85%
 Linear air shrinkage................ 17.50%
 Volume air shrinkage............... 45.75%
 Steel hard at cone 010.

 Fire tests:
Temperature. Linear Shr. Volume Shr. Color.
 Per Cent. Per Cent.
 950*C. 2.5 6.7 Brick red.
 1050 2.5 7.6 Brick red.

 One of the Chattahoochee limestone residual clays, which is an exception to the average condition found in the county, occurs in the northeast edge of River Junction where a plant manufacturing common brick was operated in 1907 by Mr. Ed Royston. The product of this plant has been used in the construction of several buildings in River Junction and Chattahoochee. This deposit is located only a few rods from the Atlantic Coast Line and Seaboard Air Line Railway tracks. Four railroads, the Atlantic Coast Line, the Seaboard Air Line, the Louisville and Nashville, and the Apalachicola Northern, meet at River Junction, thus affording shipping facilities to points in west Florida and southern Georgia and Alabama.

 The Royston deposit is irregular in thickness but is as much as fifteen feet in places and underlies a fairly extensive area in a small valley at River Junction.

 This is a red-burning clay of medium shrinkage and good drying qualities and working. It may be used for ordinary structural materials such as common brick, hollow-block ware, drain tile, etc.
 It has the following physical properties:


 Physical Properties of Royston Clay, River Junction (Lab. No. 0-71).
 Plasticity, judged by feel............ Excellent.
 W ater of plasticity................. 28.45%
 Pore water ........................ 1.66%
 Shrinkage water ................... 26.79%
 Linear air shrinkage ................ 11.7 %
 Volume air shrinkage................ 29.4 %
 Modulus of rupture, average........ 451.8 pounds per square inch.
 Slaking test ....................... 2 minutes.