GEOLOGY OF THE WEST INDIES 
263 
group. The former are always spoken of as the “ 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 rooks 
of Mesozoic 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 pf 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. 700—707. 
f Ilill, E. T., “Geology of Jamaica,” pp. 200—216. 
