THE TANGANYIKA BASIN. 281 



nearly stationary, though probably it has been 

 on the whole sinking. 



The simple inference is that some local accumu- 

 lation, perhaps remaining in action for four or five 

 years, temporarily blocked the Lukuga, which is 

 now cutting down its cataracts and gradually 

 lowering the lake. 



The state of my health quite precluded any 

 really scientific study of this question, but the 

 former highest level of Tanganyika could be easily 

 recognised from a study of the ravines in the hills 

 immediately surrounding it ; and from those which 

 I saw I should be much surprised to learn that it 

 ever rose more than this amount — 21 feet above 

 the present condition. 



Sometimes the lake is very beautiful ; little 

 rocky islands and small cliffs rise boldly out of the 

 water, for the hills in such places usually reach 

 the water's edge and are covered everywhere by 

 trees not very close together, and usually some 

 six inches to a foot in diameter. In the narrower 

 valleys which wind amongst them, one still finds 

 dense forest and a little fine timber, but the supply 

 of the latter seems to me limited and bound to 

 diminish rapidly. 



Every here and there, as at Rumonge, Ujiji, 

 and Kareini, one finds a large flat plain usually 

 of alluvium, though sometimes of a very sandy 

 character. Probably these will have considerable 

 value in the future, for the Arabs and French 



