CHAP. XIX THE MADAGASCAR GROUP 419 



in the latter portion of the Miocene or early in the 

 Pliocene period.^ 



It is clear, therefore, that if Madagascar had once formed 

 part of Africa, but had been separated from it before 

 Africa was united to Europe and Asia, it would not contain 

 any of those kinds of animals which then first entered the 

 country. But, besides the African mammals, we know 

 that some birds now confined to Africa then inhabited 

 Europe, and we may therefore fairly assume that all the 

 more important groups of birds, reptiles, and insects, now 

 abundant in Africa but absent from Madagascar, formed no 

 jDart of the original African fauna, but entered the country 

 only after it was joined to Europe and Asia. 



Early History of Africa and Madagascar. — We have seen 

 that Madagascar contains an abundance of mammals, and 

 that most of them are of types either peculiar to, or 

 existing also in, Africa ; it follows that that continent must 

 have had an earlier union with Europe, Asia, or America, 

 or it could never have obtained any mamm.als at all 



^ This view was, I believe, first advanced by Professor Huxley iu his 

 " Anniversary Address to the Geological Society," in 1870. He says : — " In 

 fact the Miocene mammalian fauna of Europe and the Himalayan regions 

 contain, associated together, the types which are at present separately 

 located in the South African and Indian provinces of Arctogtea. N"o'\\' 

 there is every reason to believe, on other grounds, that both Hindostan 

 south of the Ganges, and Africa south of the Sahara, were separated by a 

 wide sea from Europe and Xorth Asia during the Middle and Upper Eocene 

 epochs. Hence it becomes highly probable that the well-known similari- 

 ties, and no less remarkable differences, between the present faunas of 

 India and South Africa have arisen in some such fashion as the following : 

 Some time during the Miocene epoch, the bottom of the nummulitic sea 

 was upheaved and converted into dry land in the direction of a line extend- 

 ing from Abyssinia to the mouth of the Ganges, By this means the 

 Dekkan on the one hand and South Africa on tlfe other, became connected 

 with the J^Iiocene dry land and with one another. The Miocene mammals 

 spread gi-adually over this intermediate dry land ; and if the condition ol 

 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 Dekkan, while 

 others might pass into both these sub-provinces." 



This question is fully discussed in my GeorjrapMcal Distribution of 

 Anrnials (Vol. I., p. 285), where I expressed views somewhat different from 

 those of Professor Huxley, and made some slight errors which are corrected 

 in the present work. As I did not then refer to Professor Huxley's prioi- 

 statement of the theory of Miocene immigration into Africa (which I had 

 read but the reference to which I could not recall) I am happy to give his 

 views here, 



E E 2 



