A PRELIMINARY REPORT ON CLAYS OE FLORIDA 
253 
which it underlies, as well as the character and thickness of the over¬ 
burden or material overlying the clay. It is also desirable to know if 
the clay is of uniform quality throughout the deposit and, if not, the char¬ 
acter and extent of its variation. This can best be done by means of 
an auger, either a “prospector’s auger” or an ordinary wood auger. 
These should be at least two inches in diameter, and should be attached 
to a shaft or pipe about three-fourths of an inch in diameter. The pipe 
can be most conveniently handled if it is cut into lengths of about three 
feet each, so that as the boring increases in depth new joints may be 
added. A T-joint should be attached to the top so that the auger may 
be rotated. Borings forty or fifty feet in depth may be conveniently 
made with apparatus of this type. 
In an area to be prospected, borings should be made about every 
fifty feet in each direction. A plot, or sketch map, should be made, 
showing the locations of the holes and an accurate record should be 
kept of the thickness, • character and sequence of the formations en¬ 
countered. 
In addition to an intelligent record being kept of each hole, sam¬ 
ples of the materials taken from the boring should be kept and properly 
labeled. In taking samples of borings of this type great care must be 
exercised so that material falling into the hole from above, or scraped 
off from the upper walls as the auger is withdrawn, is not included 
with the samples. 
The samples from each boring, and particularly those from the 
clay stratum, should be carefully examined, in order to note any ap¬ 
parent changes in character, laterally or vertically, and to determine its 
thickness from place to place. 
Samples taken by an auger are satisfactory for determining the 
thickness and extent of a clay deposit and any variations which may 
exist in it. For the determination of the physical properties of the clay, 
however, larger and cleaner samples are desired than is usually possible 
to obtain with an auger. Digging a pit is the most satisfactory method 
of taking a clay sample. A sample of any size desired can then be obtained 
and a detailed inspection of the deposit made. For a large deposit several 
pits should be dug. 
The location of a clay deposit* with respect to transportation, mar¬ 
kets, fuel, etc., should be given very careful consideration. A clay 
suitable only for structural materials would be of little value unless 
located very near a line of transportation and where there is an ample 
supply of fuel. 
