A PRELIMINARY REPORT ON CLAYS OF FLORIDA 
69 
CHAPTER II 
CLASSIFICATION OF CLAYS 
Clays may be classified in a variety of ways, according to their 
origin, mode of occurrence, properties, or uses. No classification yet 
proposed, however, has satisfactorily treated such a diversity of factors. 
A classification based upon the origin would be of special interest to 
the geologist, while a ceramist would be more keenly interested in one 
based upon their physical properties. A classification based upon the 
uses of clays is probably the least satisfactory of any due to the fact 
that there is a very great range in the kind of clay used for any one 
purpose, and that one clay may be used for several different purposes. 
In the past three decades no less than nine 1 separate classifica¬ 
tions have appeared in the literature dealing with clays. While none of 
these are satisfactory in every respect, three of them deserve careful 
consideration. 
Ries’s 2 classification is based primarily on the geological occurrence 
and secondarily on the firing qualities of clays. It follows : 
A. Residual clays. (By decomposition of rocks in situ.) 
I. Kaolins or china clays. White-burning. 
(a) Veins, derived from pegmatite. 
(b) Blankets, deposits, derived from extensive areas of igneous or 
metamorphic rocks. 
(c) Pockets in limestones, as indianaite. 
II. Red-burning residuals, derived from different kinds of rock. 
B. Colluvial clays, representing deposits formed by wash from the foregoing 
and of either refractory or non-refractory character. 
iOrton, E., Clays of Ohio, Ohio Geol. Survey, VII, p. 52, 1893. 
Wheeler, H. A., Clay Deposits, Missouri Geol. Survey, XI, p. 25, 1896. 
Ladd, G. E., Preliminary Report on the Clays of Georgia, Georgia Geol. Sur¬ 
vey, Bull. 6A, p. 12, 1898. 
Buckley, E. R., The Clays and Clay Industries of Wisconsin, Wis. Geol. Survey 
Bull. 7, Part I, p. 14, 1901. 
Orton, E., Jr., Quoted by Beyer, S. W., and Williams, I. A., Technology of Clays, 
Iowa Geol. Survey, Vol. XIV, p. 40, 1903. 
Grimsley, G. P., Clays, Limestones, and Cements, West Va. Geol. Survey, Vol. 
Ill, p. 70, 1905. 
Ries, H., Clays, Their Occurrence, Properties and Uses, p. 27, 1908. 
Grout, Frank F., and Soper, E. K., Preliminary Report on the Clays and Shales 
of Minnesota, Minn. Geol. Survey, Bull. II, p. 18, 1914. 
Parmelee, C. W., Further Investigation of Illinois Fire Clays, Bull. 38, Ill. Geol. 
Survey, p. 10, 1921. 
2 Ries, H., Clays, Their Occurrence, Properties and Uses, p. 27, 1908. 
