86 THE TANGANYIKA PROBLEM. 



the series abut abruptly up against the western wall of the 

 great valley in which Kivu lies to the south, and these two 

 western cones are quite distinct in character from any of 

 those to the east. They are both, at present, fully active, 

 and both present the squat, truncated form of a volcano in 

 the first phase of its activity. The rim of the immense 

 crater of the more southern mountain, Kirungo-cha-Gongo, 

 we found to be 11,350 feet above the level of the sea, and 

 the mountain to the north-west, Kirungo-cha-Moto, is a 

 little lower. 



The whole appearance of these, the Mfumbiro Mountains, 

 is magnificent and impressive in the extreme. And although 

 they contain no individual eminence, anything like so high 

 as Kilima-Njaro, they form a still vigorously active volcanic 

 massif, which is vastly more imposing and extensive than 

 either Kenia, Kilima-Njaro, or Elgon. 



As has been said, the walls of the valley containing Lake 

 Kivu to the south, are not really interrupted by the volcanic 

 dam, they pass its slopes to the east and the west, and 

 again enclose the central eurycolpic fold immediately to 

 the north of the transverse line of cones. Having passed 

 over the mountains, we see, in fact, that their northern 

 slopes sweep away into the floor of the depression many 

 miles, and the volcanic ash and lava-streams are found, 

 finally, to run out upon the alluvial plains which bound the 

 southern shore of the Albert Edward Nyanza. The alluvial 

 substance of these plains runs, in fact, actually back again 

 southwards underneath the more modern volcanic matter 

 which has been piled upon them ; and there are several 

 facts connected with their character and structure that are 

 of the utmost importance, when we come to interpret the 

 phenomena which this highly peculiar district presents. 



The fauna of Lake Kivu is, as I have described in 



