■ DISCUSSION OF THE GEOLOGY. 



INTRODUCTORY. 



THE conclusion of the descriptive text of these contributions to the Tertiary 

 Fauna of Florida and the coastal plain of the Southeastern United States 

 brings us to a point where we ma_y take stock of the additions to geological 

 knowledge involved in these studies. 



Before proceeding to the census of the several horizons developed by these 

 researches it is proper to state the circumstances under which material was 

 gathered (so far as they have not already been laid before the reader) and 

 what material has been available. 



Besides the personal work of stratigraphical study and paleontologic col- 

 lecting in the field done by the writer, Mr. Willcox, and Mr. Johnson, reference 

 to which has already been made, I have had the advantage of collections made 

 by several of the Geological Survey staff in some cases with the direct intent 

 of throwing light on the Florida work. Dr. E. A. Smith, State Geologist of 

 Alabama ; the Hon. T. H. Aldrich, of Birmingham, Alabama; Colonel Thomas 

 L. Casey, Engineer Corps of the United States Army ; Dr. J. W. Spencer, late 

 State Geologist of Georgia ; Professor W. B. Clark, State Geologist of Mary- 

 land ; Professor G. D. Harris, of Cornell University, State Geologist of Louisi- 

 ana ; Dr. E. W. Hilgard, of California, formerly State Geologist of Missis- 

 sippi ; Mr. E. T. Dumble, while State Geologist of Texas ; Professor Robert 

 T. Hill, associated with Professor Alexander Agassiz in the geological study 

 of the West Indies ; Mr. T. Wayland Vaughan, of the United States Geo- 

 logical Survey, while detached for geological exploration of the island of Cuba, 

 as well as during his work in the United States ; — by these and numerous other 

 gentlemen I have been afforded kind cooperation and most important con- 

 tributions of material for study and comparison. Much of the earlier work 

 was summarized in Bulletin 84 of the United States Geological Survey, and 

 the map included in Part H. is reprinted from that prepared for the Bulletin. 



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