EEPORT OJSr THE FLOMDA EEEFS. 
KEPOET OF PROFESSOR A6ASSIZ TO THE SUPERINTENDENT OF THE COAST SURVEY, ON 
THE EXAMINATION OF THE FLORIDA REEFS, KEYS, AND COAST. 
Cambridge, Augiist, 1851. 
Sir, — The following report of the examination made by me of the Florida 
reefs, keys, and coast is prepared in compliance with your request. 
Topography of Florida. 
To form a correct idea of the Florida reefs, it is of paramount importance 
to keep in mind the topographical features of the whole country. The 
peninsula of Florida projects between the Gulf of Mexico and the Atlantic, 
from the 30th degree of northern latitude nearly to the 24th, as a broad, 
flat, low promontory, which has generally been considered a continuation of 
the low lands of the Southern States. But, as we shall see hereafter, this is 
not the case, or, at least, not with respect to the southern extremity of the 
peninsida, which consists of the same formations as the reef itself Again, 
in a physical point of view, Florida is hot limited to those tracts of land, 
forming the peninsula, which rise above the level of the sea, for the exten- 
sive shoals along its southern extremity, between the main-land and the 
keys and reefs, as well as those extending to the west as far as the Tortugas, 
whence they stretch along the western coast, in fact belong to it, and are 
intimately connected with it, by their physical character. There is a similar 
tract of flats along the eastern shore, but it is not so extensive as on the 
southern and western shores, nor does it partake as largely of the peculiar 
character of the peninsula, being chiefly formed of the alluvial sand, drifted 
ashore by the waters of the Atlantic. 
We shall have occasion, however, to show hereafter that the narrow 
longitudinal islands, which extend close to the main-land almost for the 
