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FLORIDA STATF GEOLOGICAL SURVEY. 
Extensive well records made in 1907-1908 in cooperation with 
the U. S. Geological Survey by Messrs. Geo. C. Matson and F. G. 
Clapp have been utilized in the preparation of this report. Data 
regarding climate and rainfall have been supplied by Hon. A. J. 
Mitchell, Director of the Florida section of the U. S. Weather 
Bureau. 
Many of the analyses included have been made in the office of 
the State Chemist especially for this report. Others have been 
made at various times by other chemists. Credit is given with 
each analysis. 
THE AREA TREATED. 
The area considered in detail in this report includes the fol¬ 
lowing counties: Brevard, Clay, Dade, DeSoto, Duval, Hills¬ 
boro, Eee, Manatee, Monroe, Nassau, Orange, Osceola, Palm 
Beach, Pinellas, Polk, Putnam, St. Johns, St. Lucie, Seminole, 
Broward, and 'Volusia. This section borders the Atlantic and 
Gulf coasts and comprises the principal artesian areas of Penin¬ 
sular Florida. 
GEOLOGY. 
A knowledge of the geologic structure is essential to a clear 
understanding of the underground water conditions. The pre¬ 
vailingly level country of Florida renders geologic observations 
difficult. Some favorable exposures occur, however, and these 
together with data obtained from well samples and well records 
permit a reasonably full understanding of the structure of the 
State. 
The formations found in Florida belong to the: Oligocene, 
Miocene, Pliocene, and Pleistocene. Of these divisions the Olig¬ 
ocene is the oldest; the Pleistocene the most recent. 
OLIGOCENE. 
VICKSBURG GROUP. 
The oldest or deepest formations reached in well drilling in 
Peninsular Florida are the Vicksburg limestones. The Vicksburg 
