EELATIONSHIP OF THE VOLCANOES OF THE WEST INDIES. 201 



the rains and streams, form tlie low mountains of the outer 

 chain of islands and the foundation of the inner chain of 

 volcanic islands, where they may be seen at many points, and 

 on the smaller islands away from the recent volcanic cones. 

 Typically they may be best observed in that little continent, 

 which we call the island of Antigua, for there the erosion 

 features of their surface have not been buried beneath the late 

 volcanic accumulation. And here we also find the formations 

 passing under tuffs which are themselves succeeded by the 

 lower Tertiary limestones. In St. Kitts the south-eastern end 

 of the island is composed of these old igneous rocks with their 

 surface features characteristically modified by atmospheric 

 agents, but in the centre of the island they are surmounted by 

 more recent volcanic cones. The same is true with regard to 

 the southern end of Martinique ; but in other islands like Xevis, 

 the mountain part of Guadeloupe, Dominica, Montserrat, St. 

 Lucia, and St. Vincent, the old igneous foundation has been 

 more or less buried by the later volcanic accumulations, AYhile 

 more detailed studies may lead to some modification of opinion, 

 the writer is inclined to regard these rocks as the remains, left 

 after atmospheric denudation, of a widespread igneous system, 

 forming the apparent foundation of the modern submerged 

 Antillean plateau. 



From the evidence left in the outer chain of islands, there 

 was little or no volcanic activity throughout the region during 

 the greater part of the Tertiary era, though further investiga- 

 tions may show that eruptions occurred, in the inner chain, 

 extravasating part of the material out of which the various 

 stratified beds of tuffs were apparently formed in the older 

 Tertiary days. Throughout the middle and later Tertiary periods 

 .all the reo'ion of the islands was a o'reat land surface whicli was 

 moulded by the erosion agents into features with broad rounded 

 outlines, the higher parts of which now form the foundations of 

 the islands. But about the close of the Pleiocene the "West 

 Indian Bridge was submerged so as to leave only small islets, 

 and marine beds containing modern forms of life were accumu- 

 lated about them. These, in several of the islands, occur resting 

 upon volcanic sands containing recent skulls of animals, showing 

 that the volcanic forces had again commenced to be operative 

 before or by the beginning of the Pleiocene period, after a more 

 or less general rest of long duration. 



The renewal of volcanic activity thus appears to have been 

 coincident with the changes which marked the advent of the 

 Pleistocene period, but it has been confined to very much more 



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