214 bulletin: museum of comparative zoology. 



the lands produced by this Mid-Tertiary revolution, it was certainly one 

 of the most marked and important events in Antillean history, and pro- 

 duced the major configuration of the islands and adjacent waters, which 

 have persisted notwithstanding the modifications of later times. It is 

 true that this configuration has suffered considerable alteration in subse- 

 quent epochs, through degradation and oscillations of level, but it has 

 remained as a major mass out of, upon, and around which all later 

 events have been carved. 



The next events in Antillean and Central American history were the 

 degradation, partial subsidence of the West Indian region, and dismem- 

 berment of this extended Mid-Tertiary Antillean land. The previously 

 connected Antillean lands were severed and dismembered into almost 

 their present outlines. The connections between the Antillean islands 

 and the Bahaman and south Floridian lands were submerged ; the waters 

 of the Gulf Stream now flowed over the latter. The Misterosa and 

 Rosalind peninsulas were submerged, and the littoral of the Caribbean 

 migrated southward and westward and impinged upon what are now the 

 land margins of Nicaragua, Costa Rica, Panama, Colombia, and Vene- 

 zuela. During this epoch it is also probable that Trinidad, Tobago, and 

 the adjacent islands were severed from the South American coast, and 

 the disconnection of Barbados from the South American continent still 

 further accentuated. No record has as yet been discovered showing 

 that the Windward Archipelago participated in this downward move- 

 ment. On the contrary, the formations recording it were not deposited 

 in Barbados, and the volcanic piles of the Caribbean were more extended 

 than at present. 



The Andean, Central American, Mexican, and Windward volcanoes 

 were as active as ever, piling up the vast eminences which from their 

 superior magnitude have so obliterated the no less interesting minor 

 topographic features. In this epoch ended, long before man had ap- 

 peared upon the earth, all traces of Antillean land expansions upon 

 which the least theory of an Atlantis could have been postulated, and 

 all attempts at restoring connections between the islands, or the islands 

 and the mainland, in subsequent epochs of late Tertiary and Pleistocene 

 time belong to the realms of fancy. 



The exact date of this late Tertiary dismemberment of the expanded 

 Antillean lands cannot be stated with exactness. In my opinion, it was 

 during late Miocene and Pliocene time, beginning with the Bowdeu 

 epoch of the Jamaican sequence. Dr. Dall holds that the age of the 

 Bowden beds is late Oligocene. It is my opinion that the stratigraphic 



