128 FLoRIDA GlOLOCIC.L su-RVY-15TI ANNUAL REPORT







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 Fic. 6-inloading a kiln. Guilford Bros. B rick Company, Blountstown, Calhoun ('ount.

 CIIARLOTTJ COUNTY
 Charlotte County is situated in south 1llorida west of Lake Okeechobee. Sands, marls and shell beds occupy the surface exposures, but no clay deposits are known at the present time.

 CITRUS COUNTY
 Citrus County is situated in the Hard Rock Phosphate region and is underlain mainly by Eocene and Pleistocene formations. Residual clays occur locally on the phosphate formations, but they are very irregular in thickness and extent and are subject to excessive cracking and warping in drying due to high air-shrinkage, hence are of no value for manufacturing purposes.

 CLAY COUNTY
 Clay County lies in the lower part of the St. Johns River valley and the eastern half of the county is extensively underlain by flood-plain clays. The western half of the county is covered by thick deposits of coarse sand with a clay content ranging from 15 to 40 per cent, imtuch of which is suitable for sand-clay road metal. The St. Johns River valley clays have been used in numerous places for common brick, and one plant now operating at Green Cove Springs uses one of the flood-plain