MINERAL INDUSTRIES. 
E. H. SELL ARDS. 
PHOSPHATE. 
The phosphates of Florida are known in the market as hard rock 
phosphate, land pebble phosphate, and river pebble phosphate. The 
plate rock phosphate now being mined near Anthony is included in 
this report with the hard rock. The soft phosphates of which there 
is a considerable quantity intermixed with other phosphates is unfor¬ 
tunately at present not recovered. 
The hard rock phosphate which is now being mined occurs along 
the Gulf side of the Florida peninsula from Suwanee and Columbia 
Counties on the north to Citrus and Hernando Counties on the south. 
It lies in pockets of irregular occurrence and extent and rests usually 
upon limestones of Vicksburg (Lower Oligocene) age. The land 
pebble deposits are of Pliocene age and are less irregular m their 
manner of occurrence than are the rock phosphate. The land pebble 
region at present productive lies to the south of the hard rock region, 
in Polk and Hillsboro Counties. River pebble phosphate is obtained 
from present and earlier river channels. That which has been mined 
has been taken chiefly from Peace River and its tributaries. The ac¬ 
companying maps (pis. XI and XII) show the location of mines which 
were in operation during 1908. 
The production of river pebble, the first of the Florida phosphates; 
mined, increased gradually from 1888 to 1893 when the maximum pro¬ 
duction of 122,820 tons was reached. From the year 1893 to the 
present time there has been, with some fluctuations, a decrease in the 
output of river pebble, the total for 1908 being 32,950 tons. River 
pebble mining near Arcadia in De Soto County which has long been the 
center of this industry was discontinued at the close of 1908. 
The discovery of hard rock phosphate was made soon after the 
beginning of the mining of river pebble. The first shipment of hard 
rock was probably made in 1890. 1 The output of hard rock phosphate 
has gradually increased from the beginning of mining to the present 
time. The total hard rock mined during 1908 was 768,011 long tons, 
which is a considerable increase over the production of any previous 
year. 
1 Cox, E. T., Am. Assoc. Adv. Sci. Proc. XXXIX, 260, 1891. 
