GEOLOGY. 169 



The next series are probably the cause of the 

 curious loop (eastwards) taken by the Mpango 

 river. They appear to be separated from Yijongo 

 by the ordinary granitoid gneiss of the Victoria 

 region, on which Kasagama's town is situated, and 

 run in a somewhat curved line from Kyatwa hill 

 towards the east. They form the northern boun- 

 dary of the low uncultivated plain which seems 

 to be the former bed of Lake Ruisamba. 



After leaving Butanuka on my southern journey 

 towards the Salt lake, I first came across a salt 

 river just before the Muhokia, and shortly after 

 crossing the latter, entered the Kaihura straits 

 area. A large crater lake occurs at Chukarongo, 

 the point where the curve of the land eastwards 

 towards the Kaihura passage begins. On the 

 road from this point to Katwe, two deep holes 

 are passed, occupied by poisonous salt lakes, which 

 appear to be undoubtedly volcanoes ; and I should 

 imagine there are others in the neighbourhood. 

 Then there is a ridge of olivine basalt, obviously 

 very fresh as compared with the old intrusive beds 

 of Ruwenzori, and after descending this, one passes 

 another clearly volcanic crater lake. Climbing up 

 the lip of this after about a mile's walking over 

 white tuff rock, one reaches the ridge on which 

 the Salt lake fort is placed, and which separates 

 the Salt lake, consisting as I think of three 

 craters, from an arm of the Albert Edward which 

 is probably another, broken into and partially 



