z6 POPULAR SCIENCE MONTHLY. 



and the Gulf of Mexico in times so recent as to correspond with the 

 great sinking of the Antillean continent. 



The land shells of the Bahamas, Puerto Rico, Haiti, Cuba, and 

 Jamaica are generally related to each other, and are more or less 

 connected with those of Yucatan and Florida, as was long ago 

 pointed out by Mr. Thomas. Bland, and more fully studied by Mr. 

 Charles T. Simpson, who has shown that the land shells are poorly 

 represented in the Windward Islands, but that they are closely allied 

 to those of South America. The larger islands have been lately 

 submerged so as to leave only their higher districts above the sea, 

 but from these small remnants the land snails could be developed 

 with local variations upon the re-elevation and enlargement of the 

 islands. On this basis the connection of the islands is affirmed, and 

 the remaining question is one of time, as we do not know in how 

 short a period specific variations may be effected. 



The occurrence of mammals is of more importance than that of 

 other animals, as they are less likely to be distributed by adventitious 

 circumstances than other groups. In the West Indies there is a 

 remarkable poverty of mammalian life. In Cuba and Haiti, six 

 living species of Capromys or Ilutia occur (three in each island). 

 These are small rodents, similar to a Pleistocene type found in 

 Brazilian caves. One species of insectivore, 8elenodon, occurs in 

 Cuba, and another in Haiti; these are of a Madagascar type, as well 

 as an iguana, a reptile found in several of the islands. The little 

 agouti occurs in the Island of Trinidad. These few forms repre- 

 sent almost wholly the indigenous mammals of the West Indies. 

 The monkeys of St. Kitts belong to the Old World, and appear to 

 have been artificially introduced. The scarcity of higher life has 

 given rise to the supposition that the islands have been separated 

 from the mainland continuously, since a period before the appear- 

 ance of modern mammals. But this generalization was made with- 

 out considering the physical history of the islands. 



In the Southern States, including Florida, there was an assem- 

 blage of many animals, such as the rhinoceros, mastodon, etc., which 

 lived in the late Miocene or early Pliocene period (according to 

 Professors Cope and Scott). This fauna became entirely exter- 

 minated without leaving any immediate successors. Nor have any 

 been found in the West Indies. This, however, is not strange, when 

 we consider how few localities are known on the continent where 

 such remains have been discovered; and, further, how the broad 

 lands of the Mio-Pliocene times were subsequently inundated by the 

 sea at the close of the Pliocene period, thus reducing the region to a 

 number of very small islands. 



Belonging to the Pleistocene period, in the Southern States, the 



