SILTING UP OF COASTS. 



173 



posite gulfs have erected conjointly.* Guadeloupe is likewise an ex- 

 ample of this phenomenon of junction between two lands of distinct 

 origin. The range of volcanic mountains which rise to the west 

 is united to the low island of the east, and the two islands are 

 now joined to each other by a marshy plain, where the waters of the 

 small canal, called" the Salt Eiver, stagnate. In the two islands of 

 Choa-Canzouni, bathed by the waters of the Indian Ocean, an analo- 



Fig. 75.— Chesil Bank. 



gous phenomenon is presented, but there the connecting bank between 

 the two islands is reduced, so to speak, to a mathematical point. 



M. Elie de Beaumont estimates the length of the coasts which owe 

 their present configuration to banks of shingle and sand to about one- 

 third of the total development of the continental sho;:es. It is in 



* Brue, Bulletin de la Societe de Geographie, 1829. 



