228 
EASTERN ETHIOPIA 
XVIII 
thus, along the eastern side of the Eift Valley in its 
deepest and most pronounced section we have the 
Kikuyu escarpment and the Laikipia escarpment. On 
the western side there is the Mau escarpment, the 
Kamasia escarpment, and so on. The characters of the 
fauna and the flora on the plateau east and west of 
the valley are alike. The floor is a tract of the table¬ 
land which has sunk many feet below the level of the 
surrounding plain, but the subsidence has not affected 
the area equally. The central portions have sunk 
most: even in this feature of the valley abruptness 
is its chief characteristic, for in crossing it, the traveller 
will find himself traversing a series of terraces, some¬ 
times a mile or more wide, which suddenly terminate 
with a boundary as vertical as the wall of a fortress. 
The faces of these scarps afford some indications of 
the immense force which led to the formation of this 
remarkable trough-like valley ; for they show that the 
rock has been torn through, and the fractured surface 
presents that same rough appearance as a sugar-loaf 
rent in twain. The abruptness of the changes are 
very remarkable. Gregory, in describing his journey to 
Baringo, relates that he was walking ahead of his caravan 
when suddenly, without the slightest warning, he found 
himself on the edge of a precipice 1,900 feet in height. 
For some hundreds of feet the cliff was absolutely 
vertical. The change was so startling that for a 
moment it made him feel giddy. 
We had a similar experience during a visit to 
Menengai. After examining the crater we made our 
way along its rim to the southern corner and suddenly 
found ourselves on the verge of a vertical wall of rock, 
absolutely bare of vegetation, black, rough, and stern. 
We were unable to determine its altitude because our 
aneroid had been stolen. 
The Eift Valley was probably caused by sub¬ 
sidence after extensive and stupendous volcanic action. 
The only thing I can compare it with is the Grand 
