160 GEOLOGY. 



being fresTi, is at all times tigUy saline, and in the hot 

 season it becomes a concentrated solution, depositing 

 crystals of carbonate of soda. It also contains other 

 salts in large quantities. 



The outlet from Ashangi is doubtless to the eastward : 

 the water, in all probability, percolates through the traps 

 and re-emerges on the flanks of the deep valley inha- 

 bited by the Asubo Gallas.^ 



It is very difficult to account for the formation of such 

 a hollow as that of Ashangi by any known process of 

 denudation. It is scarcely credible that it can be an 

 area of depression ; the higher series of traps capping 

 the hills around are remarkable for the absence of aU 

 evidence of disturbance : and it is difficult to conceive 

 the formation of a small deep lake by gradual or rapid 

 sinking without supposing this to be only one in a series 

 of disturbances which would leave unmistakeable traces 

 on the formations around. It is, however, certain, 

 that the lower group of traps ^ near Ashangi is much 

 disturbed, though not more so than it is in many other 

 places, where the upper group is perfectly horizontal. 



There is not the smallest trace of glacier action, and it 

 may fairly be inferred that the denudation which would 

 destroy all traces of glaciers would also fill up the lake 



1 The valley immediately south of Ashangi, in which stood the camp of 

 Masagita, appeared to me to be equally without an outlet. It was impossible 

 to examine it, however, to the eastward, and other observers thought differ- 

 ently. But I cannot help thinking it possible that the accumulation of water 

 in this hoUow during the rainy season may have occasioned the representation 

 on all the old maps of a small lake immediately south of Ashangi. 



' For the distinction between these two, see posteh. 



