GEOLOGICAL FKAIi RES OF THE WEST INDIES 385 



reared their summits to twenty thousand feet or more, 

 connecting all the Antilles into a body of Land,and pro- 

 ducing the Atlantis which we first inscribed. This 

 mountain-making epoch was the one which produced the 

 remarkable east-and-wesl folds we have so frequently 

 mentioned in these pages, and which formulated the 

 presenl major geography of the Antilles. With this oro- 

 genic revolution ended the volcanic disturbances of the 

 Greal Antilles, bu1 the Caribbean vents were piling their 

 heap- of tuff and cinder higher and higher. 



Then followed another general subsidence throughout 

 the region in the fourth quarter of the Tertiary history. 

 This subsidence was great, but not so profound as thai of 

 the previous epochs. It was sufficient, however, to cu1 

 up the Antillean Atlantis into its presenl island mem- 

 bership, to carry beneath the waters the former lands 

 represented in the now submerged banks, and to restore 

 the limits of the narrow ridge from which rose the Carib- 

 bean Volcanoes. 



Iii later geologic time, when great glacial sheets covered 

 the North American region, and since then, the West 

 Indian region has been rising again in most places, 

 although subsiding in others. The old banks of the 

 Caribbean Sea and submerged platforms around the 

 islands were brought up to within one hundred fathoms 

 of the surface, and upon them the reef-making coral 

 polyps found lodgment and began to add their contribu- 

 tion to the rock-making forces of the earth. This is 

 shown by elevated benches of reef rock around so many 

 of the islands, and by the elevated wave-cut ten-aces of 



Cuba and Haiti, to which we have called attention. 



During these later changes there is no reason to suppose 

 that the two greal basins of the American Mediterranean 

 the Gulf of Mexico and the Caribbean Sea at any 

 time lost their genera] integrity or connection with the 

 mother oceans, although their limits were expanded and 



contracted, and ;it tunes they may have been invaded by 



