106 Papers from the Marine Biological Laboratory at Tortugas. 



Sellards. Each of these men has made a distinct contribution to our 

 knowledge of the geology and geologic history of the region. 



In the preparation of this paper I have received assistance or advice 

 from several of my scientific colleagues, and express my thanks for their 

 kindness. Professor Charles E. Munroe advised me regarding some of the 

 chemical problems; Mr. J. C. Hoyt supplied information on the surface 

 run-off of streams on the Atlantic slope of the United States; Rear- 

 Admiral Pillsbtiry, U. S. N., retired, discussed the oceanic currents with 

 me; and Dr. Wm. H. Dall, Mr. George C. Matson, Mr. Samuel Sanford, 

 Dr. L. W. Stephenson, and Dr. Paul Bartsch each read my manuscript. 

 Mr. Matson made physical examinations of the bottom samples col- 

 lected and has contributed the report published on pp. 120-125 of this 

 paper, and Dr. Dall has furnished a note on the Suwanee ^Strait region 

 during Miocene time. 



Geologic research in Florida, and in Southern Florida particularly, 

 is not now the difficult and hazardous task it was even 10 or 15 years 

 ago. The Florida East Coast Railway has extended its line from the 

 mainland along the keys, and canals have been cut into the Everglades, 

 the excavations for both the railway and the canals revealing excellent 

 exposures hitherto obscured by soil and dense vegetation. Numerous 

 wells, of which we have records, have been put down on both the main- 

 land and the keys, and the shallow-draft naphtha launch renders easy 

 and speedy the examination of banks and keys hitherto accessible only 

 with difficulty. The recently increased facilities for investigation have 

 not been neglected, and results have been obtained sometimes at variance 

 with former opinions, as might have been anticipated. 



This is to be regarded as only a sketch of the geologic development 

 of the Floridian Plateau, as many problems need solution and many 

 phases of its history need further investigation. Perhaps its principal 

 value may be in directing attention to some of the unsolved problems. 

 It is necessary to know more accurately the amount of water discharged 

 by the streams and the quantities of solids borne by them to the sea. 

 The chemical processes of precipitation have not been sufficiently studied. 

 Dall's researches on the paleontology of Florida have been epoch-making 

 in their importance, but still our knowledge of the fossils of most of the 

 geologic formations and horizons is far from complete. Additional 

 paleontologic research is needed for every geologic formation known in 

 the State, from the formations of the Vicksburg group to those of the 

 Pleistocene. The paleontologic studies should be an accompaniment 

 of more detailed stratigraphic work. Topographic maps and detailed 

 geologic mapping are essential before the details of the successive defor- 

 mations to which the area has been subjected can be ascertained. There 

 is also great need for more extensive studies of the marine bottom 

 deposits within the loo-fathom curve. 



The deep wells recently put down on Key Vaca, Big Pine Key, and 

 Key West have given valuable data, but deep wells are also needed on 

 Key Biscayne or Virginia Key, the Marquesas, and the Tortugas, in 

 order to discover what underlies the surface formations. It is important 

 to ascertain whether the Miami oolite is older than or contemporaneous 



