THE TANGANYIKA PROBLEM. 
5 1 
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. 
4 * 
