338 THE TANGAXYIKA PROBLEM. 



the sea ; but even if there were such evidence, unless it 

 was of the most positive and trenchant kind, not mere 

 negative appearances, I should regard it as being quite 

 worthless in the face of the positive zoological facts of 

 the case. 



It would seem in fact that it is inherently impossible 

 to arrive at any positive geological evidence which would 

 actually veto the possibility of the sea having reached Tan- 

 ganyika. For example, suppose it could be shown definitely 

 that there were no marine deposits in a certain county in 

 England, is that fact in itself proof positive that it has 

 never been below the sea ? The problem is not one which, 

 it appears, can be solved along geological lines ; but the 

 facts of zoology are before us, and are plain enough to any- 

 one who likes to take the trouble to understand them ; and 

 if the negative geological appearances of Central Africa 

 remain and in reality cannot be brought into accord with 

 them, this simply shows the impotence of the geological, 

 as compared with the zoological, methods of research. 

 Zoological evidence having, in fact, to be brought forward 

 to indicate to geology the gross outline of the past history 

 of Africa, and the way out of the theoretical entanglements 

 in which it is at present wrapped up. 



