Geographic Character: West Indies. 129 
Oligocene, formed by foramineferous deposits, while the later are Pliocene, 
Pleistocene and recent age laid down as littoral, or reef material on marginal 
terraces, which prior to their submergence were probably wave-cut. The first 
definite evidence of the existence of Jamaica and the other Antillean islands 
is found in the eruptive rocks of late Cretaceous times, and the land debris 
constituting the strata of the Eocene testifies to the pre-existence of extensive 
Cretaceous land areas. A profound subsidence in later Eocene and early 
Oligocene times submerged all but the summits of the highest Antillean 
mountains, and this movement extended to the margins of the surrounding 
continents. A tremendous uplift in late Oligocene, or Miocene times con- 
nected many of the islands and perhaps these with Central America without, 
however, bridging the interval between the North and South American con- 
tinents. The islands were again severed in the last quarter of Tertiary time 
by submergence and assumed their present forms, which have been affected 
subsequently by only secondary modifications. Since then there have been 
intermittent periods of elevation without serious deformation, but not sufficient 
to restore the islands to the heights of mid-Tertiary time. 
f. The Bahamas. 
This‘group of islands represents a vast marine bed, or submerged plateau 
parts of which raised above the surface of the sea as dryland, form an archi- 
pelago stretching through a total distance of 780 miles (1255 km) from the 
eastern coast of Santo Domingo. The archipelago consists of over 690 islands 
and islets and 2387 rocks. The islands are not composite in construction but 
according to Professor A. Agassiz, they represent wind-blown piles of shell and 
coral sand rather than coral-reef rook. More extensive in the past their areas : 
have been restricted by a general regional subsidence of some three hundred 
feet, so that much of their former surface exists as submarine banks covered 
by shallow water. The sand, which enters into their constitution, is white shell- 
sand, the particles formed by the breaking of shells and corals into fragments. 
Reefs encircle these islands where the coral polyps are still active. The prin- 
cipal islands are grouped together in several natural groups. Thus in the 
north, we find Great Bahama Island, Great and Little Abaco islands with 
several cays forming one division. Andros Island, the largest of the Bahamas, 
with New Providence, Eleuthera, Cat, Great Exuma and Long islands form 
another group, while Crooked, Acklin, Mariguana, Great and Little Inagua, 
Turk and Caicos islands form the most southern division of. the series. Watling 
Island, the first land fall of Columbus in 1492, stands by itself in the Atlantic 
Ocean east of Cat and Long islands. The islands are all low in relief, the 
highest hill in the whole range of islands is only 230 feet high. The soil, 
although thin, in very fertile. From the sea, the Bahama islands appear as 
low stretches of verdure covered land bordered by a strip of white beach 
before which lies in the open bays water of transparent beauty, so clear, that 
the socalled sea-gardens of coral and seaweed can be seen at the bottom. 
Harshberger, Survey N.-America, 9 
