THE TANGANYIKA PROBLEM. 
4i 
encountered a succession of rising granitoid ridges and 
elevations, which finally culminate in the huge mountains 
forming the east coast of Lake Nyassa, these mountains 
being in fact the last and highest of a succession 
of granitoid ridges separated by valleys of varying 
View across the great Central Eurycolpic fold from the Northern slopes of 
the Mfumbiro Mountains. 
depth and extent. The trend of the ridges is from 
north to south, and the valley in which Nyassa lies 
is the broadest, and the deepest, which we have 
encountered during our supposed journey from the 
east. Crossing the valley of the lake towards Kota 
Kota, we find that it sinks to, and below the level of, 
the sea, and then we pass up again over the alluvial 
