Geuloyy of Xorthcastern West India Idaiuh. 189 



There is little clonbt that St. Croix, also, is the continuation 

 of the same beds, although the depth between the Virgin Islands 

 and St. Thomas is enormous, abont 4,000 meters. The A^irgin 

 Islands and St. Croix are then to be regarded as the lofty sum- 

 mits of a submai'ine Alpine parallel chain. The time at Avhich 

 this chain began to be formed, or when the pressure from north 

 or south commenced to work, is certainly after the period when 

 the Turonian strata were deposited, probably in the time of the 

 white chalk ; and there is evidence that the forces were still 

 acting after the Eocene time, as will be seen further on. In 

 the Miocene time the chain was finished, and ready for the de- 

 l)osit of the almost horizontal and little-disturbed Miocene lime- 

 stones. 



The island of Porto Eico consists largely of very thick, almost 

 undisturbed limestone beds of Miocene age ; but in the interior 

 of the country, around Utuado, rocks similar to the Cretaceous 

 of the Virgin Islands, are met with. The same geological struc- 

 ture will be found in Jamaica, near Bath, and in the Clarendon 

 District, as Mr. Barrett has stated. In San Domingo, too, the 

 iOretaceous beds, with associated syenite-like eruptive rocks, are 

 of great extent.* In Cuba, also, they seem to be present. 

 Everywhere the strata are strongly tilted, disturbed, raised, and 

 highly metamorphosed. 



The large West Indian islands contain, then, ridges of raised 

 Cretaceous rocks, and the Virgin Islands form their eastern out- 

 crops. South of the Virgin Islands, they are not met with, ex- 

 ce2)t in Trinidad, where they form the "older Parian" forma- 

 tion of Mr. Wall. It may be regarded as uncertain whether 

 the strata of Scotland, in the Island of Barbadoes, belong to the 

 Cretaceous or Eocene formation. 



EocEXE FoEMATio]sr. — East of the Virgin Group are the two 

 islands of St. Martin and St. Bartholomew, which belong to the 

 Eocene time. St. Bartholomew consists of a thick set of clastic 



* See G-ahh, on the Topography and Geology of Santo Domingo. Trans- 

 actions of the American Pliilosophical Society of Pliiladelphia, XV, Part 

 I, 1878. 



