168 A NATURALIST IN MID-AFRICA. 



perfect little cones, with a deep blue lake in the 

 centre and composed of whitish volcanic tuff or 

 agglomerate often dipping away from the centre. 

 I notice on Captain Lugard's map the word 

 " cones ' near one of these at Yijongo, which 

 shows that the credit of discovery is due to him. 



I am not at all surprised that he did not notice 

 others, for I passed and frequently saw one hill, 

 named Kyatwa, without the smallest idea that it 

 was a volcano until my return journey when I 

 ascended it and saw on the other side a perfect 

 crater-lake which it probably once enclosed. 



These recent volcanoes may be roughly grouped 

 as follows : 



1. The Yijongo series. 



2. The Butanuka series. 



3. Kaihura straits area. 



4. The Karimi volcano. 



To which it is extremely probable that the 

 following outlying hills, not visited by me, may 

 have to be added — Ruansindi, Ibanda, and Kivari. 



Besides these evidences of volcanic activity I 

 found two hot springs on the mountain. One of 

 these was a small tributary of the Wimi river, and 

 the other was on the west side of the mountain 

 not far from the Butagu river. 



The Yijongo series seem to consist of four or 

 more little cones and one rather large lake of 

 which the cone has disappeared. 



