126 Papers from the Marine Biological Laboratory at Tortiigas. 



SOURCES OF MATERIAL. 



Table of Geologic Formations in Florida. 



Silica. 

 The presence of siliceous sand in the northern portion of Biscayne 

 Bay is accounted for by similar material overlying the Miami ooHte in 

 the adjacent regions, and by the streams emptying into the bay mechan- 



