A PRELIMINARY REPORT ON CLAYS OE ELORIDA 
135 
and makes it worthless for burned products. For its physical properties 
see Lab. samples Nos. 0-19 and 0-72 under Manatee County, page 184. 
The Bartow clay is exposed in the northern portions of the county. 
See page 195 for a detailed description of the Bartow clay, Lab. Sam¬ 
ple No. 0-53. 
DIXIE COUNTY 
Dixie County lies in northern Florida and adjoins the Gulf of Mex¬ 
ico. No clays other than very loose sandy ones are known in this 
County. 
DUVAL COUNTY 
Duval County is situated in the lower St. Johns River valley. Some 
sandy clays suitable only for sand-clay road material occur in the ex¬ 
treme southwest corner of the county along the Trail Ridge. Flood- 
plain clays are common along the St. Johns River and several of these 
have been worked in the past for common brick, while one plant at South 
Jacksonville is now engaged in the production of structural materials 
from two beds of these clays. 
Two clays are exposed in the Gamble and Stockton Brick and Tile 
Company’s plant at the end of Hendricks Street in South Jacksonville. 
A section of the deposit is as follows : 
Sand, loose, brown ... 2 feet 
Clay, red mottled . 8 feet 
Sand, white ... 2 feet 
Clay, blue, very plastic. 10 feet plus 
The exact depth of this lower clay is not known as the workings 
have not reached the bottom. The loose brown surface sand at the top 
of the section is removed by a scraper. The white sand is mixed with 
the red and blue clays to reduce shrinkage and the two clays are used 
in equal proportions. 
This deposit is now being used for the production of common and 
face brick, interlocking hollow block tile, and drain tile. The ware is 
molded in a stiff mud end cut machine and burned at cone 3 in circular 
down-draft kilns. Seger cones are used to indicate the progress of 
burning. 
