THE FUELERS EARTH DEPOSITS OF GADSDEN COUNTY. 
WITH NOTES ON SIMILAR DEPOSITS FOUND ELSEWHERE. 
IN THE STATE. 
E. II. SELLARDS AND HERMAN GUNTER. 
INTRODUCTION. 
Fullers earth is a clay differing from other clays chiefly in that it 
is light and porous, and possesses in a high degree the quality of 
absorbing greasy substances. This earth was formerly used by fullers 
to remove greasy spots from cloth, from which usage it receives its 
name of fullers earth. 
The fullers earth of Gadsden County occurs as strata interbedded 
between sandstone or bluish to yellowish sands, varying in places to 
calcareous and shell bearing marls. The fullers earth itself rarely 
contains fossils. Both vertebrate and invertebrate remains, how¬ 
ever, are occasionally found immediately above and below the fullers 
earth. In Manatee County fullers earth is found lying above a marl 
or limestone, and beneath a calcareous clay or marl. 
Fullers earth, like other clays, is complex. It consists not of a 
single mineral, but of a variety of minerals; the mineral particles be¬ 
ing mixed in widely varying proportions, resulting in a variable 
chemical and mineralogical composition. Under the microscope the 
Gadsden County fullers earth shows angular particles of quartz to¬ 
gether with green double refracting particles which Merrill regards 
as a siliceous mineral. 1 In fullers earth from Arkansas, Merrill ob¬ 
served sharply angular colorless mineral particles, faintly double re¬ 
fracting, but lacking crystal outlines or other physical properties 
such as would determine their exact mineral nature. Angular parti¬ 
cles of quartz and a few yellowish iron stained particles suggestive of , 
residual products from decomposition of iron magnesia silicates were 
also recognized in this sample. The fullers earth from Surrey, Eng¬ 
land, according to the same writer, consists of extremely irregular 
eroded particles of a siliceous mineral and of minute colorless particles 
suggestive of a soda lime feldspar. Thus it may be said that while 
fullers earth is known to consist like most other clays of a mixture 
1 Report of the U. S. Nat. Museum, 1899, p. 338. 
