abstracts: geology 459 



has probably led to the introduction of a number of names for deposits 

 which upon further study can be placed in a single formation. An ex- 

 ample of this is the Vicksburg group, consisting of limestones of lower 

 Oligocene age, which is divided into three formations identical in litho- 

 logic character but having shghtly different geographic distributions. 

 The upper Oligocene contains sands, clays, fuller's earth, marls, and lime- 

 stones. It is known as the Apalachicola group and comprises several 

 formations that may eventually be reduced in number. 



The Miocene is well represented in western and central Florida by 

 fossiliferous marl, and along the east coast by siUceous limestone. The 

 Pliocene beds are of varying types, from the marine Caloosahatchie marl 

 to the nonmarine vertebrate-bearing beds of the Alachua clay. Lime- 

 stones including oolites and reef rock, partly coraliferous, of Pleistocene 

 age, underhe most of the southern part of the state. Other Pleistocene 

 beds comprise shell marl, coquina, and siliceous sand. 



The underground waters of Florida constitute a most important 

 natural resource. The waters are generally hard from the abundance 

 of limy material in the containing beds and in places are decidedly saline, 

 but they are used as sources of supply for domestic and manufacturing 

 purposes in many cities and villages. The conditions determining the 

 occurrence of flowing wells, the distribution of flowing well areas, and 

 the artesian prospects in each county are discussed in detail. 



G. C. M. 



