N 
FREE INSTITUTE OF SCIENCE 
VEGETATION OF SOUTH FLORIDA 
Largo limestone formed from the ancient coral reef. The writer believes 
that the evidence of the vegetation is sufficient to prove that, although 
contemporaneous, or even earlier, in formation than the Miami-Key West 
oölitic deposits, the Key Largo limestone was elevated later above the 
surface of the sea, thus forming a land bridge between the disconnected 
areas of Miami-Key West on the mainland and in the extreme western 
groups of keys. The evidence for this view will be presented subsequently. 
Lostmans River limestone is a non-oölitic fossiliferous one, which 
apparently underlies the western coast of southern Florida with outcrops 
exposed inland. These limestones underlie the gray sands of the main- 
land, the marls of the coastal swamps, the islands of the southern portion 
of the Ten Thousand islands, and extend along the southwestern border of 
the Everglades. The stratigraphic position of this limestone has not been 
determined with exactness. Sanford* thinks that the Miami-Key West oölite 
is younger than the non-oölitic limestones which lie between its north and 
south divisions, and the fact that in general the west coast of Florida is older 
than the east coast and the facts of plant distribution lend support to this view. 
There is a widespread covering of sands through the central part of the 
peninsula of Florida and these sands extend southward to Miami on the 
east coast and to Everglade on the west coast. These sands have probably 
been blown inland from the material carried southward along the eastern 
shore of North America by oceanic currents. At the surface, the sands are 
white or gray, below the surface they are of yellow, orange, and red hues. The 
deposits in southern Florida of recent age consist of peat, of marl, of sands, of 
coral reefs, and of oyster banks. The peat has been formed most extensively 
to a depth of one to two meters (about six feet) in the Everglades. The marls 
have been laid down on beaches, in swamps, and in lagoons and on the sea 
bottom, such as the limey oozes that cover wide expanses of the bottom of the 
Bay of Florida and elsewhere. The recent quartz sand deposits are those of 
the beaches and the wind-blown sand of the dunes. On the east coast these 
end with Key Biscayne, for the beach sands of Soldier Key and the series of 
islands extending to Key West are calcareous. "The recent coral reefs are found 
off the arc of the Florida keys from Soldier Key to the Tortugas, and they are 
of the barrier type. "The seaward slope is steep, but the living coral polyps 
carry on their work in water one and a half to 8 meters deep, where heads and 
* Sanford, Samuel: Second Annual Report Florida Geological Survey, p. 219. 
