98 THE TANGANYIKA PROBLEM. 



Passing still farther to the west, these lacustrine plains 

 came to an end abruptly beneath the western flanks of 

 the Semliki valley, and over these we are instantly once 

 more on the Congo watershed. It will thus be seen, 

 that in the regions of the Mountains of the Moon, we are 

 still dealing with precisely the same phenomena encountered 

 when we considered the construction of the great eurycolpic 

 depression in the region of Nyassa and Tanganyika. That 

 is to say, the gross, geological characteristics of the region 

 have been brought into existence by a folding of the earth's 

 surface along two parallel lines of up-push, each of which 

 is apparently coincident with the faulted walls of the 

 depression itself. The only modification of this process 

 which has occurred in the region of the Mountains of the 

 Moon being, that, for about a hundred miles on the eastern 

 side of the Semliki river, the crinkling and uprising has 

 been so violent that the lower rock masses underlying the 

 Victoria Nyanza plateau have been forced through it, just 

 as if the igneous base, upon which the sandstones of Mount 

 Waller rest, was to be forced up and up, until it tilted 

 the sandstones on both sides of it, and, finally, towered 

 above these old aqueous deposits in ridges of intrusive 

 igneous matter, 15,000 ft. to 16,000 ft. in height. I do not 

 think there is the least doubt that this has been the real 

 method and nature of the formation of the Ruwenzori 

 range, and, consequently, we must view the massif as simply 

 a more vigorous and local expression of the flanking 

 mountain chains which appear along the sides of the 

 eurycolpic folds in other places, as in the region of the 

 Livingstone range on Nyassa, or the great outstanding- 

 masses which, at several points, tower over the general 

 level of the sides of the Tanganyika basin. 



From these considerations it would appear that Stuhl- 



