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CHAPTER III. 



ON THE EXISTENCE OF A GREAT CENTRAL MOUNTAIN CHAIN 



IN AFRICA. 



In entering upon an enquiry concerning the nature of the 

 fauna of the great lakes of Central Africa in general, and 

 that of Tanganyika in particular, it is, if not absolutely 

 necessary, at any rate advisable, that a conception of the 

 structure of the continent, as concise and accurate as 

 existing observations will permit, should be formed first. 

 On this account I have prefaced the chapters dealing with 

 the zoology of the Great Lakes by some in which the 

 structure and the geology of the vast regions in which 

 the lakes lie has been described as fully as our yet 

 scanty information will allow. In the present instance 

 this course is doubly to be desired : our views respecting 

 the continent are becoming changed, and some very 

 definite theoretical anticipations which have been put 

 forward concerning the gross geological features of the 

 African continent appear, in the light of the most 

 recent exploration, to have hardly even a shadow of 

 support. These older geological anticipations are, more- 

 over, diametrically opposed to some of the most salient 

 zoological facts relating to the fauna of Lake Tanganyika, 

 and consequently any fresh information about the geo- 



