Volcanic Disturbances in West Indies 229 



In Guadeloupe we have much evi- 

 dence concerning the evolution of the 

 volcanic range and the mass of sedi- 

 mentaries. This island is composed of 

 two parts, of about equal area, sepa- 

 rated by a shallow creek or strait, Ri- 

 viere Salee. The most western of these 

 islets (Basse-Terre) is a typical volcanic 

 pile of the main Caribbee chain and is 

 thoroughly mountainous. The most 

 eastern area (Grande-Terre) is an ele- 

 vated constructional plain, composed of 

 sedimentary formations of Pleistocene 

 age, underlain by a platform of volcanic 

 tuffs, etc. Still to the eastward of 

 Grande-Terre is the small terraced isl- 

 and of Desirade, composed entirely of or- 

 ganic material, which.with several other 

 islets, stands above a shallow submerged 

 platform extending out from the south- 

 east end of Grande-Terre and Basse- 

 Terre. To the southward of Grande- 

 Terre is the island of Marie Galante, of 

 the same topographic and geologic type 

 as Grande Terre. 



Moreaude Jonnes, in 1816, discovered 

 that even these calcareous outer islands 

 of the Caribbee chain rested on igneous 

 formations. He showed that the calca- 

 reous islands were all situated externally 

 to the windward of the volcanic shore, 

 and that even in the volcanic islands 

 where calcareous formations were also 

 found the latter were always on the At- 

 lantic side. In fact, there is evidence 

 that the line of volcanic activity has mi- 

 grated westward slowly during geologic 

 periods. 



Concerning the origin, relation, and 

 succession of volcanic events the follow- 

 ing facts can be stated : In late Creta- 

 ceous time vulcanism was active in the 



now quiescent regions of the North Mex- 

 ican and Trans-Pecos Cordilleras, the 

 Coastal Plain of Texas, the Isthmus of 

 Panama, and the Great Antilles, Ja- 

 maica then being a volcanic island. The 

 late Cretaceous limestones of Costa Rica 

 contain angular specks of volcanic ma- 

 terial intermixed with them, as also do 

 the late Eocene sediments of Panama, 

 which facts lead us to believe that the 

 present Central American volcanic pla- 

 teau has been an intermittent locus of 

 volcanic activity from the Cretaceous to 

 the present, as also has the volcanic re- 

 gion of Mexico. 



The volcanoes of the Windward Isl- 

 ands, in my opinion, date back to at 

 least the Eocene. Eater in the Miocene 

 vulcanism became quiescent in the great 

 Antilles, but continued in the four great 

 loci of present activity — Southern Mex- 

 ico, the Northern Andes, Central Amer- 

 ica, and the Windward Islands. In the 

 last two regions mentioned the greater 

 masses of the present volcanic heights 

 were piled up before the Pliocene, and 

 the present craters are merely secondary 

 and expiring phenomena. 



Synchronously with the regional up- 

 lifts of late geologic time, volcanic pil- 

 ing has continued on the mainland and 

 in the Windward Islands, although the 

 mass of ejecta during these later days 

 is Lilliputian in comparison with the 

 great heaps of debris piled up in pre- 

 ceding epochs. The present craters and 

 vents of the Mexican, Costa Rican, and 

 Windward summits are mere ant-hills 

 capping older mountains of ejecta. The 

 last volcanic fires of the Cordilleran re- 

 gion of Northern Mexico and the United 

 States expired in Pleistocene time. 



CARIBBEE VOLCANOES * 



It has been so long since any explo- 

 sions have occurred in the Caribbee Isl- 



* It is one of the most lamentable admissions 

 of our lack of geographic knowledge to state 

 that no traveler, geologist, or explorer has ever 

 systematically visited all these vents and craters 

 or published anythingupon them asan entirety. 



ands that most geographers as well as 

 the inhabitants were of the opinion that 



I must confess that in my own studies of the 

 islands there were more difficult problems of 

 paleontology, stratigraphy, and physiography 

 throwing light upon their evolution and his- 

 tory, which occupied my time and attention. 



