A PRELIMINARY REPORT ON CLAYS OF FLORIDA 251

 CHAPTER XI

 METHODS OF PROSPECTING FOR CLAYS

 It has been pointed out that this report does not attempt to include the clay deposits of Florida that are not within a reasonable distance from transportation, and as general development continues within the State, it is very probable that many deposits of clays in close proximity to transportation will be found, that are not known at the present time. It is considered expedient, therefore, to include a few general suggestions here for those who may be interested in locating new clay deposits and determining whether or not the clay is of sufficient quantity and proper quality to warrant commercial development. The same suggestions may be followed by those desiring to determine the available supply or the clay reserves in deposits already known or worked. These suggestions are designed to fit geologic and physiographic conditions in Florida, and while in general the principles of clay prospecting are the same for any type of deposit, or in any geologic region, different criteria are to be observed and conclusions drawn in a region of sedimentary rocks and of low relief, as is the case in Florida, from those which are most important in crystalline rocks or in a mountainous area.
 The presence of clay deposits *may be detected in wells, in road or railway cuts, in excavations for buildings, along streams, in canals, and in cliffs or banks of lakes, or along the sea shore. It often happens that clay exposures are concealed under a mantle of sand or soil or a dense growth of underbrush. In many places the presence of the clay bed is often revealed by springs or a seepage of water, particularly where the clay stratum is overlain by a porous material, as sand or soil. In some cases clay beds may be determined by the character of the vegetation growing on the surface. In the absence of natural outcrops or exposures in wells, etc., the presence of clay beds must be determined by borings, which can be done best with a small auger, described on page 253.
 A few preliminary tests should be made upon the clay to determine whether or not it is even worth while to prospect the deposit in detail. Tests of this character are of little importance in indicating the real value of the clay, but, at the same time, the results may be negative and show the clay is not suited for use in manufactured products.