240 The National Geographic Magazine 



Photo by Robert T. Hill 



The Beach shows the Force of the Return Wave {page 26/) 



nally either erupted as lava or represent 

 the cooled stocks within the necks of 

 former craters which have been exposed 

 by erosion. The greater mass of the 

 material, however, is in the form of vol- 

 canic tuffs and conglomerates represent- 

 ing the old crater-thrown debris, in 

 many cases worked over by the streams 

 of the successive eruptions. This is 

 beautifully exposed in the numerous 

 bluffs, from 50 to 200 feet in height, 

 which everywhere mark the truncated 

 line of the northwestern peninsula. 



GEOLOGICAL HISTORY 



The configuration and sequence of 

 formations indicate the following im- 

 portant events in the history of the 

 island : 



1. That it originally consisted of vol- 



canic piles rising from the sea bottom 

 in the area along the eastern shore. 



2. That Montagne Carbet and Pelee, 

 constituting the northwestern promon- 

 tory, are successively newer and later 

 volcanoes, which have grown parasitic 

 to the westward of the older and orig- 

 inal volcanic site. 



3. That Martinique has been losing 

 in area to the eastward b}' the plana- 

 tion of the sea and growing to the west- 

 ward by the successive eruptions of 

 ejecta. 



4. The elevated deltas and marine 

 formations bordering the seacoast tes- 

 tify that in addition to the growth of 

 this island by piling up of ejecta it has 

 participated in the epeirogenic move- 

 ments which marked the history of all 

 the West Indies in late Tertiary and 

 Pleistocene times. 



