222 FLORIDA GEOLOGICAL SURVEY-15TH ANNUAL REPORT 
Moreover the present deposits of this material probably represent 
remnants of a formerly continuous deposit covering, at least, a large 
portion of central-peninsular Florida. The presence of quartz and mica 
indicates that the material was derived from the residual clays of some 
granitic region, probably upper Georgia. That the ultimate source of 
the material was to the northward is indicated by the fact that the 
larger pebbles are found in the northern part of the region as is pointed 
out by Ries. 1 
Davis 2 in attempting to explain the high plasticity of these clays 
says that they are probably flood-plain clays and are supposed to have 
resulted from the transportation and deposition of material from a 
granite area. In continuing this same line of thought, Watkins 3 says: 
“It is very probable, however, that this kaolin was first deposited in 
Cretaceous times and later eroded and transported to its present posi¬ 
tion. As this portion of Florida is several hundred miles farther from 
the crystalline area than the Cretaceous horizon, it is reasonable to sup¬ 
pose that the particles of kaolin held in suspension for so great a dis¬ 
tance would be more finely divided than those which were deposited 
in Cretaceous beds. This, to some degree, may account for the fact 
that the Florida clays are more plastic than the Cretaceous clays.” 
A different theory was earlier suggested by Sellards 4 when he 
said: “The admixture of finely divided clay, kaolinitic in nature, with 
the coarse sands which characterize these deposits, is difficult to account 
for, except upon the hypothesis that when deposited the formation con¬ 
sisted of coarse quartz and feldspar sands. The quartz being more 
resistant has remained but little changed, forming the coarse sand 
of the formation. The feldspar sands, since their deposition, have been 
subjected to decay, thus forming the kaolinitic -clay of the present for¬ 
mation.” 
This theory encounters serious objections. If climatic and phy¬ 
siographic conditions similar to those of the present are postulated 
1 Ries, H., The Clays of the United States East of the Mississippi River, U. S. 
Geol. Survey Prof. Paper No. 11, p. 82, 1903. 
2 Davis, N. B., The Plasticity of Clay and Its Relation to Mode of Origin. 
Trans. A. I. M. E., Vol. 51, pp. 451-480, 1916. 
8 Watkins, Joel H., White-Burning Clays of the Southern Appalachial States, 
Trans. A. I. M. E., Vol. 51, pp. 481-501, 1916. 
4 Sellards, E. H., The Soils of Florida, Florida Geol. Survey, Fourth Annual 
Report, p. 21, 1911. 
