146 BARBOUR: ZOOGEOGRAPHY. 



the forms wliich have been left imprisoned, as it were, upon any island at the 

 time of its separation from the land with which it formerly was in connection. 



Zoologic evidence can never outweigh or set aside positive geologic evidence. 

 It can never hope to place the time of a geologic change with the accuracy that 

 geologic evidence does, when the latter exists. Unfortunateh^, convincing 

 geologic evidence is, in tliis region, frequently wanting. In the East Indies, as 

 in the West Indies, we may, it is true, postulate extensive land connections as 

 existing in a recent geologic past, and as having only in some cases left behind 

 them evidence of their existence in the shape of elevated ridges or shallow areas 

 on the bottom of the sea. 



The origin of the fauna of the West and East Indian areas presents a 

 condition of affairs singularly parallel. In the West Indies there has been an 

 immigration of land types into Haiti and Porto Rico, and thence to the Lesser 

 Antillean chain, which have come by land connections stretching from Cuba to 

 Yucatan, on the one hand, and to Haiti on the other; and again from the 

 Mosquito Coast to Jamaica, and thence to Haiti. There has also been a 

 connection of Florida with Cuba, and of Cuba with the Archipelago of the 

 Bahamas; for these islands have drawn more of their fauna from Cuba than 

 they have from Haiti, though the latter is nearer to some points of the Bahamas. 

 Then, up to the Lesser Antillean chain has come an immigration of animals 

 which have been derived from the region of Ai-chiguiana, or part of the Gond- 

 wana land of Suess (Face of the earth; translated by Hertha B. C. Sollas 

 4 vols., Oxford, 1904-1910; 1, p. 387; 4, p. 471, 663). This faunal element 

 from what is now northeastern South ^America is predominant in Trinidad and 

 Tobago, recently separated; very strong in Grenada; and less so in St. Vincent. 

 It reaches up to Porto Rico, where it still forms a prominent part of the whole 

 fauna, and is naturally less evident in Cuba and Jamaica (Barbour, Bull. M. C. Z., 

 1910, 62, p. 275-285). 



In the East Indies the case is more complicated, but the main features of 

 the two-fold origin are the same — am influx of mainland tjrpes from south- 

 eastern Asia, on the one hand; and an influx of types derived from Antarctis, 

 on the other (Antarctis = AustraUa + Patagonia. Cf. Suess, 4, p. 667-669). 



The points of view of both zoologist and geologist are fast changing regard- 

 ing the extent to which one may assume that alterations have taken place in tlie 

 shape of existing land-masses. There has been up to recent times a strong 

 tendency on the part of English, and some American, geologists to look upon the 

 ocean basins as fundamental surface features of the earth, which have existed 



