ELEVATION OF WEST INDIAN AREA 287 



Bahamas, by land. How far eastward this land extended 

 cannot be determined from the mammals, but it certainly 

 must have reached beyond the Virgin islands to Anguilla, one 

 of the most northerly islands of the Lesser Antilles. Many 

 islands of the Lesser Antilles may have been completely 

 submerged at that time. Later on Cuba, the Bahamas and 

 Jamaica were connected with the mainland, after the other 

 islands had already been separated from the Antillean land- 

 mass, and lastly, Cuba and Jamaica were independently joined 

 to Central America before the existing physical features were 

 brought about. 



. Many more details are required before we can cionstruct 

 an approximate history of the geological events which led to 

 the present conditions of the fauna and flora of the Antilles. 

 In his chapter on the evolution of middle America Dr. 

 Gadow * deals with the problem from the aspect of the 

 reptilian and amphibian fauna. He does not attempt to recon- 

 struct the geological history from a study of tJiis fauna alone. 

 His maps are derived and abstracted from the opinions ex- 

 pressed by various geological authorities. They are in so far 

 of importance, as he thinks, that the general conclusions 

 based on a geological study appear to fit those founded on 

 faunistic cionsiderations. Several striking points may be 

 gathered at a glance from his maps. At no time since the 

 Cretaceous Period were the Antilles direatly connected with 

 the main continent of Nort'h America. Only in Miocene times 

 was " Antillea" (the term used for the united Antilles) joined 

 to southern Florida, the latter being then disconnected from 

 North America. Antillea had only one continental connec- 

 tion, namely, during the Miocene Period by means of Central 

 America. It follows, therefore, that Antillea never was directly 

 joined either to North or South America, at least not since 

 Cretaceous times. If Dr. Gadow's maps are oorreot, the whole 

 of the Antillean fauna and flora, in so far as they are derived 

 from migration on land, should be of Miocene age or older. 

 Dr. Gadow's conclusions would have been of greater value had 

 he trusted more to the evidence based on geographical dis- 

 tribution and less on that of geology. As pointed out by 



* Gadow, H., " Mexican Amphibians and Eeptiles," pp. 234 — 237. 



