THE WEtiT INDIAN BRIDGE. 



29 



duration of geological time. It is such magnificent land forms as 

 these plateaus and great valleys, found submerged beneath the sea, 

 which have furnished us with the means for measuring the terrestrial 



movements in the opposite direction wliich have reduced the West 

 Indian region to a group of islands. 



As to the causes of these terrestrial movements, at present little 

 can be said. Changes of level of land and sea, similar to those found 



