A CONTRIBUTION TO THE GEOLOGIC HISTORY OF THE 

 FLORIDIAN PLATEAU. 



By Thomas Wayland Vaughan. 



INTRODUCTION. 



This paper is the outgrowth of my association with two organiza- 

 tions, the United States Geological Survey and the Carnegie Institution 

 of Washington. As Geologist in charge of Coastal Plain Investiga- 

 tions of the former organization, I have had unusual opportunities 

 to famiharize myself with the geology of Florida, supplementing my 

 previous field work in the State by several additional trips. I super- 

 vised and participated in the preparation of a report on the stratigraphic 

 geology and a geologic map of the State, done in cooperation between 

 the United States Geological Survey and the Florida State Survey, by 

 Messrs. George Charlton Matson, Frederick G. Clapp, and Samuel San- 

 ford. I have therefore had at my disposal not only the results of my 

 personal work for the Geological Survey, but also those of Messrs. Matson, 

 Clapp, and Sanford. The information derived from my association with 

 the United States Geological Survey is here utilized with the permission 

 of the Director of that Bureau, and my hearty thanks are extended to 

 him for the privilege. 



Through facilities afforded by Dr. Alfred G. Mayer, Director of the 

 Department of Marine Biology of the Carnegie Institution of Washington, 

 I have been able to visit all the principal keys belonging to the main 

 line, to collect and study bottom samples between Miami and Key West, 

 particularly the deposits accumulating behind the keys, to examine 

 several important living coral reefs, and to make detailed investigations 

 of the reefs around the Tortugas. I was also able to visit Cat and Gun 

 keys and the Picquet rocks of the Bahamas. 



It was at first contemplated to give an account only of the sedi- 

 mentation now taking place in the bays and sounds behind the keys. 

 Naturally, the questions arose, whence come these sediments, by what 

 processes are they brought to the sea, how great is their quantity, and 

 how are they distributed over the ocean floor? An extension of these 

 questions led to a general consideration of sedimentation on the Floridian 

 platform and the growth of the platform itself. 



The scope of the paper was therefore enlarged, and an attempt is 

 made to trace the geologic history of the Floridian Plateau from Oligo- 

 cene to Recent time. The work of previous investigators has been exten- 

 sively drawn upon, and the debt owed them is gratefully acknowledged. 

 The principal of these are Louis Agassiz, Alexander Agassiz, Eugene A. 

 Smith, Angelo Heilprin, WilHam H. Dall, N. S. Shaler, Leon S. Griswold, 

 George C. Matson, Frederick G. Clapp, Samuel Sanford, and E. H. 



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