DEPARTMENT OF MARINE BIOLOGY. 



233 



Current measurements were made with Ekman meters at 19 stations. The 

 readings were made by Mr. John Mills, chief engineer, Mr. George Tracy, 

 sailing-master of the Anton Dohrn, and Mr. W. M. L. Wilson, in charge of the 

 launch Velella. The records clearly show a westward set of the current in 

 Hawk Channel and south of Tortugas. 



The cross-section of Loggerhead Key and the spit at its south end were 

 remeasured so as to record changes in the position of the shore-line. A plane- 

 table survey of the shore-line of the key, on a scale of 500 feet to 1 inch, is 

 here reproduced on a reduced scale. A geologic map of the key was also made. 



As I am preparing an article on the effect of currents on the shore-line physi- 

 ography of southern Florida and on the building and shaping of keys and banks, 

 no more detail will here be given on these subjects. 



Fig. 8. — Loggerhead Key, Tortugas, Florida. 



Lighthouse, Lat. 24° 38' 04" N., Long. 82° 55' 42" W. From a plane-table survey by 

 T. Wayland Vaughan, June 10-13, 1914. 



a. North spit of key, June 21, after swell from west, June 16-18. 



