154 GEOLOGY. 



The surface of the Abyssinian plateau, as has already- 

 been stated, has been deeply scored by the valleys in 

 which the rivers flow. Many of those in Northern 

 Abyssinia are remarkable enough : the Takkazzy^ and 

 Mareb flow in ravines at least 3,000 feet in depth. But 

 it is in the area of bedded traps that these river valleys 

 assume their most peculiar characters. The gorges of 

 the Jitta and Bashilo, close to Magdala, impressed every 

 one who saw them by their great depth and the excessive 

 steepness of their sides, the breadth being singularly small 

 in comparison. Similar deep gorges are known to be 

 found further south.^ 



No such gorges can possibly result from marine denu- 

 dation. The fiords of Norway, which are far broader in 

 proportion to their depth, are glacier valleys, and certainly 

 not due to the action of the sea. There is not the 

 slightest evidence of any physical disturbance which 

 could have produced such rents in the earth's surface ; 

 the strata which cap the scarps at each side of the ravines 

 are perfectly horizontal. There has as certainly been no 

 faulting, at all events in the case of the Jitta ; bed corre- 

 sponds to bed on the opposite sides of the gorge in the 

 most perfect manner. There cannot be a question but 

 that these enormous hollows are simply channels cut by 

 the streams which run in them. The lapse of time 



1 One is described by M. Rocher d'HMcourt as traTe-sing part of Shoa, at 

 a distance of fourteen leagues north-west of Angolala, one of the principal 

 towns. This ravine is said to be 1,254 metres (about 4,000 feet) in depth, 

 and only 700 to 800 metres (2,500 feet) in breadth ! It is to be presumed 

 that the measurements were taken at a spot where the width was exception- 

 ally small. 



