, TRANSACTIONS OF WAGNER 



VEGETATION OF SOUTH FLORIDA 



clumps of coral rise to the level of low tide. Banks of solidly packed oyster- 

 shells make bars at the mouths of many of the rivers, as in the case of the 

 Caloosahatchee River. 



During Pleistocene age, there was a period of submarine upbuilding of 

 quartz sands and calcareous material moved southward by oceanic currents. 

 A depression of 30 meters (100 feet) occurred later, during which the beach and 

 bar deposits grew in thickness on the east coast and the coral reef grew and 

 spread southward of the mainland. Quartz sands, calcareous sands and muds 

 accumulated in the shallow water off the west coast. Following this depression, 

 according to Sanford,* there was a brief uplift of the land to possibly 60 meters 

 (200 feet). Beach sands were driven inland and formed dunes. The coastal 

 limestone was eroded by the sea and honeycombed by rain-water. Following 

 the uplift came a depression which brought the land surface nearly to its 

 present level. The Everglades in recent times have been formed in the south- 

 ern part of a lake larger than the present Lake Okeechobee. Sands and muds, 

 and other materials, were deposited along the shores of mainland and keys and 

 have contributed materially to the formation of the present shore line. 



The last element of the geology of South Florida, which concerns this 

 general description, is the Caloosahatchee marl which represents Pliocene 

 deposits, first discovered by Heilprin in 1887 and to which he gave the name 

 Floridian. The Caloosahatchee marl is a light-gray shell-marl, often 

 interbedded with nearly pure sand. It is usually very calcareous, but 

 locally sand is abundant. The shells that enter into the formation of the 

 marl are in a remarkable state of preservation and so easily identified. The 

 thickness of the beds along the Caloosahatchee River is on the average 

 about 2.4 meters (eight feet). Occupying a low level, the marl beds have 

 been dissected by river action to only a slight extent. This marl includes 

 all of the elevated land between Caloosa and Labelle, when with an east- 

 ward dip they are finally covered by deposits of Pleistocene age. Along this 

 stretch of river, there are numerous exposures of the Caloosahatchee marl 

 between Caloosa and Labelle, where they have a thickness of i meter, be- 

 neath i meter of fossiliferous Pleistocene marl covered by i meter of 

 sandy loam. 



Other localities are known along streams entering into Charlotte 

 Harbor, where similar marl beds occur. Such are the Caloosahatchee beds 



* Sanford, Samuel: Second Annual Report Florida State Geological Survey, 231. 



