1901-2.] The Windward Islands of the West Indies. 369 



the western, on account of the eastern slopes being the more 

 precipitous, and the soundings fewer in number. Between the 

 Grenadine and Trinidad banks (see Plate D), the connecting plains 

 may not be submerged to more than 750 feet, except in a narrow 

 channel. The various forms of the valley-like indentations of the 

 border of the great submarine Antillean plateau are similar to those 

 upon the slopes descending from the high tablelands of Mexico and 

 Central America, which have been fashioned by the rains and streams, 

 and accordingly their occurrence is interpreted as evidence that the 

 former altitude of the now sunken plateau was as great as the 

 present submergence of the valleys now drowned. This conclusion is 

 only to be modified, in referring to the islands, or their districts, which 

 have been the scene of Pleistocene or more recent volcanic activity, 

 for here we find local elevation due to plutonic forces which have not 

 affected the great earth movements of the region. Among the Wind- 

 ward Islands the evidence of the full height at which the land stood 

 has not been determined, as among the Bahamas and on the south- 

 eastern margin of the North American continent, where we have found 

 that it exceeded 12,000 feet. At the time of the great elevation of the 

 Antillean plateau, the region west of the Caribbean sea — Central 

 America — ^was low. 



The valleys are the result of two periods of erosion, — namel}^ that 

 of the Miocene-Pliocene, with the production of broad rounded forms, 

 and that of the early Pleistocene days when the elevation reached the 

 maximum height and all the islands were united so as to connect South 

 and North America. This last epoch was of the shorter duration with 

 the deepening of the old valleys, the formation of cailons, and the 

 excavation of cirques or amphitheatres, at the heads of the narrow 

 valleys, as they were dissecting the tablelands. 



In the remains of elephants, and the large rodents of Guadeloupe 

 and Anguilla, we have confirmatory evidence of the great elevation 

 during the early Pleistocene epoch, for these mammals migrated from 

 the continent about that time. But all the Pleistocene animals have 

 disappeared from this region, and the modern species have not found 

 their way to these islands, for since the very general subsidence which 

 exterminated the former species, there has been no connection between 

 the islands and the continent. 



Beyond the proper limits of this study, between St. Croix and St. 

 Thomas, of the Virgin Island banks, there is a remarkable basin 

 attaining a depth of 15,000 feet (see map, Plate F), unlike any other 



