THE BUILDING OF THE LAND 31 



blanket of sand reaches as far south as Miami and 

 Cape Florida on the southeast coast, and to Cape 

 Sable on the southwest. But the manner in which 

 it has been so generally distributed over Florida in 

 almost level beds, is probably not well understood. 

 At these two points the siliceous sands rather 

 abruptly cease and to the south the sand of the 

 beaches is composed entirely of broken bits of 

 coral, shells, and other marine growths, — with 

 little or no trace of quartz or of the older rocks. 



There have been no violent convulsions, no 

 sudden or great disturbances during the geological 

 history of Florida since the original uplift of the 

 Florida bank, yet a ceaseless construction and 

 destruction of land have been goiiig on within its 

 limits. The new land formed yesterday of silt 

 washed down by streams, by elevation or by the 

 deposition of vegetable matter, is being dissolved 

 to-day by carbon dioxide, worn away by stream 

 or surf action or carried below by subsidence. 



