114 Papers from the Marine Biological Laboratory at Tortugas. 



head is 264 feet above tide, and near the Alabama line some localities 

 may be somewhat higher, small areas perhaps exceeding 300 feet.' 



Before leaving the subject of the relief of the subaerial portion of 

 the Plateau, two features should be mentioned. All areas delimited by 

 contours above the 50-foot Ue to the west of St. John's and Kissimmee 

 rivers and north of the latitude of Sarasota. Most of the lakes of the 

 State occur in the more elevated region, or along its western or southern 

 periphery. This distribution of more elevated areas, particularly with 

 reference to drainage Hnes, will be discussed subsequently. 



MARINE BOTTOM DEPOSITS FORMING IN THE BAYS AND 

 SOUNDS BEHIND THE KEYS. 



During the latter part of April, 1908, I went from Miami to Key 

 West on the yacht Physaha; and also made a short excursion from Miami 

 to Cat and Gim keys of the Bahamas. The route followed from Miami 

 to Bahia Honda Key was that known as the "inside passage," but 

 several short side-excursions were made outside the main line of the 

 keys in a smaller launch. One object of making the trip within the main 

 line of the keys was to procure bottom samples, particularly for ascer- 

 taining the nature of the deposits now being laid down behind the keys. 



The specimens were procured by attaching a cup to the bottom 

 of the sounding lead; they were then put into glass bottles with screw 

 tops and brought to the laboratory for more detailed investigation. 

 The material after arriving in the Geological Survey office was placed in 

 the hands of Mr. G. C. Matson for examination. His report is given on 

 subsequent pages. 



For convenience of discussion the material will be described from 

 (i) Biscayne Bay, (2) Card Sound, (3) Barnes Sound, (4) Blackwater 

 Sound, (5) Hoodoo Sound, (6) Florida Bay, (7) Material from Cat and 

 Gun keys, Bahamas. 



A few beach specimens will be discussed in connection with the 

 bottom deposits of the neighboring waters, and in a similar connection 

 a few bottom specimens obtained from the outside of the keys will be 

 considered. 



' G. C. Matson, Preliminary Report on the Geology of Florida, Fla. Geol. 

 Surv., 2d Ann. Report, p. 30. 



