The Geology of Florida in Relation to Artesian 
Water Supply. 
BY DR. E. H. SELLARDS. 
Mr. President, Ladies and Gentlemen: 
In its general geology Florida is fortu¬ 
nately of comparatively simple structure. 
Tlie formation^ of the state have suffered 
no great distortion since their deposition 
and lie for the most part nearly horizon¬ 
tal as formed, or with a slightly accentu¬ 
ated dip. For a clear understanding of the 
water supply problem a conception of the 
leading features of the geology of the 
state is essential. 
The underlying foundation rock 
throughout the state is a massive and 
very thick limestone. In character the 
limestone is granular, soft and with many 
shells, and, for the most part porous. 
Borings indicate that water circulates 
freely through it. The conditions of for¬ 
mation, as indicated by 'the rock itself, 
were, clear water free from land sedi¬ 
ment in which shell life flourished abund¬ 
antly. This foundation limestone is com¬ 
monly known as the Vicksburg limestone, 
or in recent years the Peninsula lime¬ 
stone. This formation we may expect 
to encounter by borings in all parts of the 
state. Beyond the coast line the forma¬ 
tion is known to extend to Costa Rica, 
a'nd there is no reason to doubt that it 
extends to the east into the Atlantic and 
to the west into the gulf basin much 
beyond' the present Florida coast, and 
is the one formation that is of uni¬ 
versal distribution throughout the state 
lying at the surface in small areas, 
but for the most part buried at slight 
to considerable depth beneath later rock 
deposits. The peninsula limestone is ex¬ 
posed at the surface except for a more 
or less thick covering of sand in local 
areas throughout Marion, Alachua, south¬ 
ern Columbia, and Suwannee Counties. 
In other parts of the State it is covered 
by later formations, indicating that while 
most of the state remained somewhat 
longer under water, the areas named 
appeared as islands at the close of the for¬ 
mation of the peninsula limestone. 
On top of the peninsula limestone 
around 'these islands and throughout the 
state in general there accumulated subse¬ 
quent marine deposits some of them of 
considerable thickness. These later for¬ 
mations are, however, more or less local 
in character and while reaching a consid¬ 
erable thickness in parts of the state no one 
of them extends unintermptedly through¬ 
out the state as a whole. Immediate¬ 
ly following the peninsular limestone 
in the central part of the state is the Ocala 
limestone, best exposed at the lime kiln at 
Ocala where‘it is something more than 
twenty feet deep. The Chattahoochee 
limestone is perhaps a little later than the 
Ocala and occurs along the Appalachaco- 
