THE TANGANYIKA PROBLEM. 75 



extending the Tanganyika valley north and south. In 

 the southern portions of Tanganyika there are no deposits 

 of any kind besides the modern lake pleistocenes and the 

 massive old African sandstones, while at the extreme 

 north there are beds which extend to about twenty miles 

 towards Kivu, and which in age appear to be intermediate 

 between the Drummond series and the pleistocenes.* 



* In this connection may be mentioned what, if the marine animals in Tanganyika 

 are a pre-cretaceous stock, has appeared to some geologists an unaccountable fact — 

 namely, that on the west coast of the continent, to the south of the Cameroon moun- 

 tains, for example, only cretaceous and post -cretaceous marine deposits have been found. 

 This matter is now, however, in the light of our present fuller information readily 

 intelligible. For we have seen that there were deposited in the interior, right across 

 the valley of Tanganyika, in fact, aqueous beds, thousands of feet thick, which them- 

 selves underlie the triassic series to the south ; and that subsequently the country was 

 raised along the axis of the Great Central Range ; in consequence of which, the deposits 

 in the interior are the oldest, and those nearer the sea, in general, progressively 

 younger, as we proceed towards the coast. 



