THE TANGANYIKA PROBLEM. 51 



on the western side of the lake as the flat-bottomed 

 gap in the western rampart of hills, through which the 

 Luakuga river, the outlet of Tanganyika, flows into the 

 Congo. 



It seems certain, moreover, from the surveys of Mr. 

 Wallace and others, that both the salt Mwero and the 

 true Mwero depressions exist in smaller branches of the 

 southern part of the great Tanganyika valley, while, as I* 

 have pointed out elsewhere, the Lufu valley and the whole 

 of Cameron gulf are included in a eurycolpic fold which 

 runs at right angles to the Tanganyika trough. 



The main Tanganyika trough, thus, both branches, and is 

 intersected by the Rukwa valley ; but beyond this point, 

 we found it to be continued and extremely well marked 

 as a single depression all the way to the Albert Edward 

 Nyanza. Here another valley strikes it, from the west, 

 and passes across the depression as the hollow in which 

 lake Ruisamba is contained. (See map facing p. 80.) 



Whether the eastern branches of the Nyassa valley really 

 are connected up with the lesser eastern series, which 

 occurs to the east of Kilima Njaro and contains Lakes 

 Beringo and Rudolf, is not, I believe, known, but it will 

 become obvious, on referring to the geological maps, 

 that the arrangement of these valleys is certainly ex- 

 tremely complex and curious. The two main systems run 

 north and south, and both round the great depression 

 in which the vast waters of the Victoria Nyanza have 

 accumulated. 



There is in fact nothing elsewhere, upon the earth, 

 comparable to this unique series of rectilinear folds, which 

 cross, and intersect one another, at all sorts of angles, 



* On the physiographical features of the Nyassa Tanganyika plateau. Journal of the 

 Royal Geographical Society, September, 1897. 



A* 



