40 
THE TANGANYIKA PROBLEM. 
respecting the structural similarity of many of the grooves 
which wander through the African interior from south to 
north was luminously summarised by Professor Suess, # 
who showed for the first time that whatever their origin, 
such chasms are a related series of phenomena, and 
that the earth movements which have given rise to them 
are by no means confined to the African interior, but have 
brought about similar phenomena in the production of the 
vast walled chasm in which the Red Sea lies fifteen hundred 
miles away to the north. Similar chasms are indeed pro- 
longed into the Gulf of Akabah and the Dead Sea even as 
far as the depression of the Jordan itself. More detailed 
information respecting the nature of the lesser eastern de- 
pression which lies between Keniaand the New Uganda rail- 
way was given by Professor Gregoryt as the result of a short 
journey to Kenia from Mombasa, but the clear conception 
of these valleys as a phenomenon which is subordinate to 
the formation of a great internal line of elevation perhaps 
naturally escaped both Suess and his followers at the 
time. They regarded the “graben" (rift valleys) as the 
primary geological feature of the African interior, whereas 
they are far more properly viewed as the interesting by- 
products of the folding of a spherical surface during a 
modern attempt on the part of the earth to raise a grand 
mountain chain. Let us, however, examine the character 
of the great African ridge, including these valleys, in some- 
what more detail than has hitherto been done. If we con- 
struct a section of the Great Central Range in the region of 
Southern Nyassa, through Kota Kota for example (see dia- 
gram No. i ), we have the following phenomena. Beginning 
at a point between the lake and the east coast, there are 
Die Briick des Ost-Afrika. 
t loc. fi/. 
