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 paleontology 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,
 HERMAN GUNTER,
 State Geologist.
November, 1923.