158 FLORIDA GEOLOGICAL SURVEY— 15 TH ANNUAL REPORT 
Fire tests: 
Temperature . 
Linear Shr. 
Per Cent . 
Absorption. 
Per Cent. 
Porosity. 
Per Cent. 
Color. 
950°C. 
0.5 
12.86 
31.50 
Brick red. 
1050 
0.5 
12.20 
30.50 
Brick red. 
1150 
0.5 
11.36 
29.70 
Brick red. 
1190 
0.5 
11.27 
29.40 
Brick red. 
1230 
0.5 
10.75 
28.30 
Brick red. 
1310 
1.0 
10.15 
28.20 
Brick red. 
Franklin county 
Franklin County borders the Gulf of Mexico and lies between the 
Apalachicola and Ocklocknee rivers. The surface exposures consist 
of sands and marls, but no clays of any commercial importance are 
known. 
GADSDEN COUNTY 
Gadsden County lies in the northwestern part of the State between 
the Apalachicola and Ocklocknee rivers and the formations exposed are 
the Chattahoochee, Alum Bluff, and a surface mantle of Pleistocene or 
Recent. The Chattahoochee, while primarily a limestone, contains some 
interbedded clays and residual clays also abound in this formation. The 
Alum Bluff consists of beds of sand, clay and fuller’s earth. In addition 
to these clays there are some more recent flood-plain clays along the 
Apalachicola and Ocklocknee rivers. 
Deposits of sand-clay road material are common in the county and 
essentially all the roads in the county are made of this material. 
Very few of the Chattahoochee formation clays, either the sedimen¬ 
tary or the residual ones, are of any value for manufactured products. 
In general their working qualities are poor. Most of them are calcareous, 
have a high shrinkage, warp and crack badly and have poor plasticity. 
A sample which may be considered as illustrative of the great mass of 
Chattahoochee clays in the county was taken at an exposure in the road¬ 
side about two miles east of the State Hospital near Chattahoochee. This 
is a grayish-green jointed clay of low plasticity, containing a few flint 
concretions and geodes. It is worked only with difficulty. This clay is 
not appreciably calcareous. In a burned condition it is suited only for 
railroad ballast. A few of its physical properties are: 
