GEOLOGY AND MINERAL RESOURCES. 
127 
MINERAL RESOURCES. 
The mineral resources of the Ocala area include in addition to 
springs and underground waters, phosphate rock, lime, limestone, 
and marl, fuller’s earth and other clays. 
SPRINGS AND WATER SUPPLIES. 
The water supply in this area is drawn chiefly from the Alum 
Bluff sands and clays and from the Ocala limestone. The water 
from sands and clays, although not obtained in such large supplies 
as from the limestone, yet has the advantage of being soft and rel¬ 
atively free from mineral matter in solution. The depth that it is 
necessary to drill or to sink a well for water varies in different lo¬ 
calities. On the hills and the uplands where the Alum Bluff forma¬ 
tion persists a supply of water sufficient for household and family 
use can usually be obtained at a very moderate depth. In the low¬ 
lands, on the other hand, it is frequently necessary to drill into the 
limestones. For deep wells from which a large supply of water is 
to be drawn it is usually necessary to continue the drill hole into 
the limestone until either a cavity 01* a porous layer is reached 
Representative wells of this area are listed in the following table. 
SPRINGS. 
Some exceptionally large springs, as well as many small ones, 
are found in this part of the State. Silver Springs at Ocala prob¬ 
ably has the largest flow of any spring in the world, namely, 368,- 
913 gallons per minute. Freight and passenger boats, following 
the stream, enter and dock at the spring, affording one of the few 
cases of a stream navigable to its very head. Blue Springs at Juli¬ 
ette is also a large spring, flowing about 346,166 gallons per minute. 
These springs flow from the Ocala limestone, and the water, as is 
usually true of limestone springs, is wonderfully clear and trans¬ 
parent, small objects being visible on the bottom of the spring at 
a depth of 40 feet or more. 
With regard to this spring Professor John LeConte who visited 
the spring in 1859 wrote as follows:* 
“The most remarkable and interesting phenomenon presented by this spring 
is the truly extraordinary transparency of the water; in this respect surpassing 
*Amer. Journ. Sci., Vol. XXXI, p. 3, i86iw 
