GEOLOGY OF FLORIDA 



E. H. SELLARDS 

 University of Texas, Austin 



To those who have seen Florida but casually it may seem that 

 the geology of the state is entirely obscured beneath the sand, soil, 

 and vegetation of the prevailingly level surface. But to those who 

 have looked more closely it is apparent that such is not the case. 

 It is true that the problems of geology are made more difficult by the 

 lack of frequent and continuous exposures, but they are not neces- 

 sarily made impossible of solution. The numerous stream channels, 

 railway and public-road cuts, drainage canals, and drilled weUs 

 afford records from which the stratigraphic succession and structure 

 of formations may, with patience and persistence, be worked out. 

 Fortunately many of the formations of the state are richly fossilif- 

 erous. Nowhere in the United States do the Tertiary and Quarter- 

 nary formations contain a more abundant, more varied, or better 

 preserved marine invertebrate fauna than in Florida. In this 

 respect there is an embarrassment of riches. Dr. Dall in his study 

 of the fossils of the Caloosahatchee marl, recognized in that forma- 

 tion alone the presence of more than 600 species of mollusks. 

 Vertebrates, although as a rule not so well preserved as the inverte- 

 brates, are relatively numerous. No state east of the Mississippi, 

 perhaps, contains so many Tertiary and Quart ernary vertebrates 

 as does Florida. Fossil plants, although less abundant than either 

 invertebrates or vertebrates, are not wanting. It is seldom the case 

 that a single formation holds both land and marine fossils, yet 

 something of an insight into the interrelation of the marine inverte- 

 brates, land animals, and land plants is secured in the Florida 

 Miocene and again in the Florida Pleistocene. In the study 

 of the fossils, Florida is in many respects a state of exceptional 

 opportunities. 



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