A PRELIMINARY REPORT ON CLAYS OE ELORIDA 
189 
mately forty feet. Water transportation via the St. Marys River is 
available at this point. 
Other brick plants have been operated about seven miles east of 
Callahan, at Yulee, and at Fernandina. 
OKALOOSA COUNTY 
Okaloosa County is located in western Florida and extends from the 
Florida-Alabama line to the Gulf of Mexico. The formations consist 
of the Alum Bluff in the northeast corner and undifferentiated sands 
and marls in the remainder of the county. Much of the surface is 
covered by a sand-clay mantle. No clays adapted to manufacturing uses 
are known in the county. 
OKEECHOBEE COUNTY 
Okeechobee County lies just north of Lake Okeechobee and east 
of the Kissimmee River. Pleistocene sands and marls form the surface 
materials. No clays of commercial importance are known to be present. 
ORANGE COUNTY 
Orange County is situated in the east-central part of the peninsula 
and lies within the Lake Region. Its surface formations are Alum Bluff 
and Pleistocene sands and marls. Reddish and brownish sandy clays 
suitable only for sand-clay roads are of widespread distribution in the 
county. 
A bluish-gray clay occurring about two miles east of Clarcona has 
been washed and found fairly satisfactory for some grades of work at 
the Orlando potteries. The overburden ranges from one to five feet of 
sand and the clay averages about three feet in thickness. The nearest 
railway is about two miles. The unwashed clay has the following 
physical properties: 
Physical Properties of the Clarcona Clay (Lab. No. 0-60). 
Plasticity, judged by feel. Excellent. 
Water of plasticity. 22.50% 
Pore water. 0.16% 
Shrinkage water . 22.34% 
Linear air shrinkage. 6.90% 
Volume air shrinkage. 19.80% 
Modulus of rupture, average. 133.1 pounds per square inch. 
Slaking test. 3 days. 
