GEOLOGY OF THE WEST INDIES 263 



group. The former are always spoken of as the u Greater 

 Antilles," and the latter as the ''Lesser Antilles." With 

 Professor Suess * we may look upon the mountain ranges of 

 Yucatan and Guatemala, which trend in a west-easterly direc- 

 tion, as the western continuations of the mountain system of 

 the Greater Antilles. The latter, as well as a few of the 

 northern Lesser Antilles, are composed of sedimentary rocks 

 of Mesozoie and Cainozoic, possibly even of Palaeozoic age^ 

 while many of the remaining smaller islands, which cluster 

 together in a concave arc, seem to be of comparatively 

 recent volcanic origin. The Bahamas, and some of the 

 more southerly flat islands, including part of Barbados, are 

 apparently of young Tertiary age. The whole of the main 

 series of the Antilles, from Cuba through Jamaica, Haiti and 

 Portorico to Barbados, is composed of similar rocks. Granite, 

 older eruptive rocks, serpentine, glauconitic sandstone and 

 cretaceous limestone, form the visible remnants of a once 

 connected mountain range. Westward the latter divides into 

 several branches. One of them passes from southern Haiti 

 through Jamaica to Honduras, another by way of Cuba to 

 Guatemala. 



There is some evidence, according to Professor Hill, that 

 the east coast of North America lay far eastward of its pre- 

 sent site in pre- Cretaceous times, whereas some faunistic 

 facts point to a continuation of this condition until the 

 Tertiary Era. The Pacific marine fauna transgressed east- 

 ward during the Jurassic Period, probably across the Mexican 

 plateau, fossils of Pacific type having been found in western 

 Cuba. This implies that the barrier separating the Atlantic 

 from the Pacific in those remote times must have been situated 

 to the east of Cuba. Professor Hillf argues that the chain 

 of low -lying islands between Florida and north-eastern South 

 America represent the remnants of this ancient Jura-Cre- 

 taceous isthmus between the two great continents. Whether 

 such a land bridge existed is difficult to determine from 

 faunistic evidence, but the Atlantic waters seem to have 

 entered the Caribbean Sea in Lower Cretaceous times. 

 During part of the Eocene and Oligocene Periods, extensive 



* Suess, E., " Antlitz der Erde," I., pp. 700707. 

 t Hill, E. T., " Geology of Jamaica," pp. 200216. 



