THE BUILDING OF THE LAND 15 



mocks along the south shore of the State over to 

 the rocky ridge east and south of the Everglades. 



The northern end of the upper chain of keys is 

 not more than eight miles distant from the rocky 

 ridge on the Miami mainland. Key Largo has 

 been cotmected with the mainland until recently 

 but the connection was a swamp never sufficiently 

 dry to permit the passage of upland forms of life. 

 Notwithstanding the nearness of these two bodies 

 of land and the fact that they are only separated 

 by the shallow waters of Biscayne Bay, Card and 

 Barnes sounds I feel safe in asserting that there 

 has never been an elevation sufficient to unite them 

 as dry land since the present life reached their 

 shores. Nor, on the other hand, has there been 

 any subsidence great enough to drown out our 

 dry-land flora and fauna since they were first es- 

 tablished. I do not believe that since the first 

 Pleistocene elevation there has been twenty feet of 

 change in elevation in all Lower Florida. 



At least sixty species of tropical plants are found 

 on the Upper Keys which do not occur on the 

 Miami mainland and a large temperate and warm 

 temperate flora grows on the latter which is 

 entirely absent from the former area. There are 



