226 FLORIDA GEOLOGICAL SURVEY— 15 TH ANNUAL REPORT 
moved by erosion, so that the deposits known at present are merely 
remnants. 
In this connection it is to be noted that the white Cretaceous clays 
of Georgia and South Carolina are relatively free from sand and peb¬ 
bles, and, with one or two exceptions, may be used without first being 
washed. Their properties are similar to the sedimentary kaolin of Flor¬ 
ida, except that the Florida clay has higher plasticity. 
The immediate source of the material, i. e., clay and sand, composing 
the deposits in Florida, is not easy to explain. If it is assumed that the 
clay was derived from the white Cretaceous clays of Georgia, then an¬ 
other source for the quartz-sand must be sought and its mixture with 
the clay accounted for. 
The source of the Florida sedimentary kaolin, its transportation, 
geologic age, relation to other sediments, terrestrial and shore-line con¬ 
ditions, distribution and deposition, are problems as yet far from being 
solved. 
HISTORY AND DEVELOPMENT 
The Florida sedimentary kaolin was discovered in 1890 1 in mining 
phosphates, and samples were sent to Mr. C. S. Edgar at Trenton, N. J. 
As early as 1875, Mr. Edgar had heard rumors of kaolin deposits in 
Florida, but, upon going there, was unable to find any. In 1892, Mr. 
Edgar began mining this clay at Edgar under the name of the Edgar 
Plastic Kaolin Company. This company is still operating at that place. 
In 1900 the International Kaolin Company began mining clay in the same 
formation at Okahumpka. There are at present three companies working 
deposits of sedimentary kaolin: The Edgar Plastic Kaolin Company, at 
Edgar, in Putnam County; The Lake County Clay Company, and the 
Florida China Clay Company, both near Okahumpka, in Lake County. 
properties 
The sedimentary kaolin in its crude form consists of sixty to seventy- 
five per cent quartz-sand and twenty-five to forty per cent clay. The aver¬ 
age is probably about sixty-five per cent sand. This natural mixture is 
washed, thus separating the clay from the sand, and a part, at least, of 
the mica. The washed product, however, probably does not represent 
1 Ries, H., and Leighton, H., History of the Clay Working Industry in the 
United States, p. 78, 1909. 
