THE TANGANYIKA PROBLEM. 



respecting the structural similarity of many of the gro 

 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 Keniaandthe Xew Uganda rail- 

 way was given by Professor Gregory 4 " 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 Xyassa, through Kota Kota for example (see dia- 

 gram Xo. i), we have the following phenomena. Beginning 

 at a point between the lake and the east coast, there are 



* Die Briick des Ost-Afrika. 

 + loc. (it. 



