ix.J PALEONTOLOGY AND EVOLUTION. 205 



the mouth of the Ganges. By this means, the Dekhan 

 on the one hand, and South Africa on the other, became 

 connected with the Miocene dry land and with one 

 another. The Miocene mammals spread gradually over 

 this intermediate dry land ; and if the condition of its 

 eastern and western ends offered as wide contrasts as 

 the valleys of the Ganges and Arabia do now, many 

 forms which made their way into Africa must have 

 been different from those which reached the Dekhan, 

 while others might pass into both these sub-provinces. 



That there was a continuity of dry land between 

 Europe and North America during the Miocene epoch, 

 appears to me to be a necessary consequence of the fact 

 that many genera of terrestrial mammals, such as Castor, 

 Hystrix, Elephas, Mastodon, Equus, Hipparion, Anchi- 

 therium, Rhinoceros, Cervus, Amphicyon, Hycenarctos, 

 and Machairodus, are common to the Miocene forma- 

 tions of the two areas, and have as yet been found 

 (except perhaps Anchitherium) in no deposit of earlier 

 age. Whether this connection took place by the east, 

 or by the west, or by both sides of the Old "World, 

 there is at present no certain evidence, and the question 

 is immaterial to the present argument ; but, as there are 

 good grounds for the belief that the Australian province 

 and the Indian and South-African sub-provinces were 

 separated by sea from the rest of Arctogaea before the 

 Miocene epoch, so it has been rendered no less probable, 

 by the investigations of Mr. Carrick Moore and Pro- 

 fessor Duncan, that Austro-Columbia was separated by 

 sea from North America during a large part of the 

 Miocene epoch. 



It is unfortunate that we have no knowledge of the 

 Miocene mammalian fauna of the Australian and Austro- 

 Columbian provinces ; but, seeing that not a trace of a 

 Platyrrhine Ape, of a Procyonine Carnivore, of a charac- 



