THE ALLEGED DESICCATION OF EAST AFRICA IB 
and the consequent greater demand for agricultural land during 
the last hundred to two hundred years or so, it is estimated 
that the area of forest has artificially been decreased by some 
3000 square miles. The rain-borne clouds sweep westward 
over the continent, and when chilled by the belt of forest on 
the higher ridges deposit their rain on the western slopes ; 
this would afford a reasonable explanation of a decrease in 
rainfall in a certain portion of the Rift valley during that 
period. It would, however, afford little explanation of the 
desiccation of the hinterland of Jubaland between Kismayu 
and Lake Rudolf. 
Another point which has been suggested is that the rate 
of elevation of the interior of British East Africa has been in 
excess of the rate of denudation, so that in effect the rainfall 
has run off so quickly that it has not had time to permeate 
the soil of the area on which it falls ; this point is, however, 
I consider, without any support. There is definite evidence 
that the glaciation over Mount Kenya extended in Pleistocene 
times to a much lower level than it does at present, and there 
is little doubt that this state of affairs had a considerable effect 
on the climate of a great portion of this part of Africa ; or, 
to express it more logically, that the conditions which produced 
a more extensive glaciation on Kenya also considerably affected 
the climate of the country generally, and the lower general 
temperature of this part of the continent would probably cause 
greater precipitation of rain. As Professor Gregory, however, 
points out with great acumen, the coastal raised beaches and 
reefs give no palaeontological evidence of contemporary reduc- 
tion in the temperature of the adjacent ocean. 
Prof. Gregory found traces of former glaciation on Kenya 
over 5000 feet below the present lowest terminal level of the 
ice, and he goes on to argue that this was due to a much greater 
elevation of the Kenya area. The present peak of Kenya is 
the denuded core of a volcano which probably at one time 
presented a dome-like shape somewhat on the same lines as 
the Kibo peak of Kilimanjaro ; the sister peak of Kilimanjaro, 
Mawenzi, may be said to be in the same stage of decay as 
Kenya. Mawenzi is about 2000 feet lower than Kibo, and so 
we can, for the purpose of argument, add 2000 feet to the height 
