5 8 THE TANGANYIKA PROBLEM. 



of our supposed boring. Where alluvium and lake deposit 

 has accumulated in this manner in vast masses, as it has 

 on the Shirwa plain, for example, and in the basin of 

 Lake Pamalombi, there are, unfortunately, no very deep 

 water cuttings to be found, and the examination of those 

 which exist by Sir John Kirk, ourselves and others, have 

 revealed nothing but the semi-fossilised remains of existing 

 land animals, such as elephants, hippopotami, and the 

 remains of fishes and fresh-water shells. In the case of 

 the great Shirwa plain, however, these lake deposits and 

 layers of terrestrial alluvium are, by whatever method we 

 may estimate them, very thick, and their deposition must 

 have gone on without break from a remote geological 

 antiquity until the present day. It is, therefore, quite 

 certain that deep excavation in such localities, or their 

 examination in some favourable spots which have yet to 

 be discovered, would reveal in their deeper portions animal 

 remains which differ from those now inhabiting the African 

 lakes and plains. There is no reason why such flats as 

 these occurring in the Shiri highlands should not contain 

 zoological remains as different from the existing fauna, 

 and as full of interest, as the remains recently obtained 

 from the very similar flats in Madagascar by Mr. Forsyth 

 Major, and more recently from Fayum by Mr. Andrews. 



PassinQ- to the west of the Shiri districts we find that in 

 part of the Nyassa region proper, as I explained in the 

 preceding chapter, the geological characters of the country 

 throughout the whole district are very similar to those of the 

 Shiri highlands ; granitoid ridges run north and south, and 

 contain between them rock valleys which are often partially 

 filled up with horizontal masses of old lake deposit and 

 alluvium, these masses themselves representing the wear and 

 tear of a country that has not changed much since the 



