LETTER OF TRANSMITTAL 
To His Excellency, Hon. Cary A. Hardee, Governor of Florida: 
Sir:—-I have the honor to submit herewith the Fifteenth Annual 
Report of the State Geologist. In addition to the Administrative Report, 
which contains a statement of the expenditures of the Survey from 
January 1, 1922, to July 1, 1923, and a statistical summary of the mineral 
industries for the years 1921 and 1922, it contains a paper on the paleon¬ 
tology of northeastern Florida by Wendell C. Mansfield of the United 
States Geological Survey, and a report on the clays of Florida by Olin 
G. Bell of Cornell University. 
In the preparation of the report on clays most of the counties were 
visited and from many of them samples were obtained. Owing to 
limited time for field work and to the finances of the Survey, it was not 
possible to collect as many samples as we would have liked, or to make 
chemical analyses. The investigation thus far conducted, however, shows 
that the State has large quantities of clay suitable for the manufacture of 
common building brick, drain tile, building tile and earthenware. The 
very plastic ball clays are admirably adapted to the manufacture of 
high-grade porcelain when mixed with less plastic clays. 
With the decreased output of lumber in Florida and the consequent 
rise in price, there comes an increasing demand for the more durable 
building materials. Clay must enter more largely into the manufacture 
of brick and building tile in this State and it is not improbable that it 
will be used in the manufacture of cement. Economic and industrial 
conditions point to a constant development of the clay industry. 
It is hoped that this report may-be the means of stimulating the 
clay industries already established and promote the bringing of others 
to the State. 
The uniformly cordial interest that you have shown toward the 
work of this Department is appreciated. 
Very' respectfully, 
November, 1923. 
Herman Gunter, 
State Geologist. 
