36 
FLORIDA GEOLOGICAL SURVEY. 
of hydrous aluminum silicates. These silicates differ in 
chemical composition, but are similar in that they all 
possess an amorphous colloidal structure. These colloidal 
silicates possess the power of absorbing and retaining 
organic coloring matter, thus bleaching oils and fats.” 
Uses:—The Florida fuller’s earth .finds its chief use in 
filtering mineral lubricating oils. According to Day, 
“The common practice with these mineral oils is to dry 
the earth carefully, after it has been ground to 60 mesh, 
and run it into long cylinders, through which the crude 
black mineral oils are allowed to percolate very slowly. 
As a result the oil which comes out first is perfectly water- 
white in color, and markedly thinner than that which fol¬ 
lows. The oil is allowed to continue percolating through 
the fuller’s earth until the color reaches a certain maxi¬ 
mum shade, when the process is stopped, to be continued 
with a new portion of earth. The oil is recovered; from 
the spent earth.*” It is also used to some extent for light¬ 
ening the color of cotton seed oil, and lard oil, although 
the English fuller’s earth is better for these purposes. The 
original use of fuller’s earth, that of cleaning, is now one 
of the minor uses. It is said to be used in the manufac- 
ture of some soaps. It is used in cleaning furs and by 
druggists as an absorbent, and recently to some extent 
as a carrier for insecticides. 
Occurrence:—Fuller’s earth occurs in stratified de¬ 
posits, which, however, are often of local extent. The 
geological horizon in which the fuller’s earth of western 
Florida lies has been determined by Vaughan as Upper 
Oligocene. The geological horizon of the deposit in Man¬ 
atee County has not been determined. 
Location and Extent:—Outcrops of fuller’s earth have 
been reported at many other localities; in Gadsden, Leon 
and Liberty Counties, and Decatur County, Georgia. It 
is reported to occur as a thin stratum in the Devil’s Mill 
Hopper in Alachua County, and has been identified by the 
writer on the property of B. S. Quarterman, at Fairfield, 
*U. S. Geo! Sur. 21st Ann. Rept. pt. 6, (cont) p. 592. 1901. 
