24 
FLORIDA GEOLOGICAL SURVEY. 
The record of land life is no less interesting. The 
earliest land inhabitants of the State yet recorded are the 
land snails, the shells of which are found sparingly in 
the Ocala limeetone. This was during Lower Oligocene 
time. The peninsula land area was then, apparently, an 
island, access to which was for ordinary land vertebrates 
probably difficult, or even impossible. It is scarcely to be 
doubted, however, that birds, bats and perhaps many of 
the small land animals found their way to the islands. 
An increased elevation occurred following the formation 
of the Lower Oligocene limestones. Evidence of this up¬ 
ward movement attended by subsequent depression is 
afforded by an unconformity between the Lower and Upper 
Oligocene limestones. This movement, if not actually con¬ 
necting the islands with the mainland, must at least have 
greatly narrowed the intervening body of water, and may 
possibly have permitted land vertebrates to reach the 
peninsula. If so, their remains will doubtless be found 
imbedded in the Upper Oligocene formations. 
By the close of the Chesapeake Miocene the peninsular 
area was sufficiently elevated to become connected directly 
with the continent, thus permitting free migration of land 
vertebrates from the continent. The remains of land ani¬ 
mals occur most commonly in clay beds which were doubt¬ 
less formed along the borders of lakes, streams, and sinks. 
The land animals found in these clays include the mas¬ 
todon, the elephant, the rhinoceros, the saber-toothed 
tiger, horses, deer, bison, tapirs, giant sloths and glypto- 
dons. The fossil remains of these animals are widely 
scattered, occurring over practically all parts of the State, 
those which have been described come mostly from 
the Alachua Clays in the vicinity of Archer and Ocala; 
from Peace Creek in Manatee County; and from the Plio¬ 
cene beds of the Caloosahatchee River. They are probably 
of Pliocene and Pleistocene age. The South American rep¬ 
resentatives in this fauna came doubtless by the way of 
the Isthmus of Panama after the connection of North 
and South America, 
