212 bulletin: museum of comparative zoology. 



Rico, Barbados, the Yirgin Islands, and the other regions mentioned, in 

 all of which the Eocene strata are greatly elevated and intensely folded. 

 For data showing the disturbance of this epoch see the various pub- 

 lished geologic sections of the other islands. 



It would be beyond all reason or interpretation of the known facts 

 to conceive that the stupendous changes of this epoch did not affect 

 the configuration of the adjacent sea bottoms. Neither the east and 

 west trends of the mountain ridges, nor the mountainous configuration 

 of the Great Antilles, cease with the margins of the water. The nar- 

 row trend of the Sierra Maestra range of Cuba, for instance, is trace- 

 able eastward by a shallow submerged ridge directly across to the 

 northwest peninsula of Haiti, and westward by the Misterosa bank, a 

 narrow mountainous submerged ridge lying between the Bartlett Deep 

 and north Caribbean basin, and extending for hundreds of miles from 

 the Sierra Maestra towards Guatemala. Furthermore, the slopes of 

 the mountains are continued far beneath the waters. The steep de- 

 clivity of the Sierra Maestra, which now projects 8,000 feet above sea 

 level, continues downward beneath the water to a depth of 18,000 feet, 

 showing indisputably that the present mountain phenomena of the islands 

 are but the tips of submerged bases. 



It is equally probable that the combined Mosquito, Rosalind, and 

 Pedro banks constituted an extensive land in this mountain making 

 epoch, connecting Jamaica with the Honduras-Nicaraguan coast. The 

 Bahaman and south Floridian banks were also probably connected with 

 northern Cuba, the Gulf Stream meanwhile flowing out across the 

 northern part of Florida. 



This east and west folding may have been instrumental in producing 

 the wonderful Bartlett trough and its related depths adjacent to Cuba 

 and Haiti, which constitute a narrow submerged furrow almost com- 

 pletely across the whole Mediterranean, as well as a parallel elongated 

 submerged trough of the northwestern Caribbean lying south of the 

 western end of Cuba and north of the Mosquito bank. These phenom- 

 ena may have been initiated at a more remote epoch, but the known 

 effects of the erogenic movements of this epoch, as now visible in the 

 mountains of the Great Antilles, were amply sufficient to produce them. 



This important Mid-Tertiary epoch of mountain making in America 

 has not been fully appreciated, but its existence shows conclusively that 

 in this country, as in the Pyrenees of Europe, there was a great east 

 and west trending system at right angles to the trends of the main con- 

 tinental Cordilleras. 



