Chapter VII. 
ranges down to their high central plateaux and thence to 
the coast level. In Africa, on the contrary, Ruwenzori 
rises from the so-called “ Albertine Depression,” a low district 
forming a region about GOO to 700 feet below the average 
level of Uganda, and containing the basins of Lake Albert 
and of Lake Albert Edward with its northern prolongation, 
Lake Dweru or Ruisamba. 
The whole of this depression forms simply a portion of 
the western “rift.” The “rifts” consist of two gigantic 
trenches, from 20 to 50 miles in width, running nearly 
parallel to one another, with an interval of 6° longitude, 
and cutting through the continent from Lake Nyassa north¬ 
ward. The easternmost of the two follows the 36th meridian 
as far as Lake Rudolph, beyond which it inclines towards 
the Red Sea. The western rift runs between the 29th 
and 30th meridian and comes to an end near Gondokoro in 
the Upper Nile Valley. Either rift includes a nearly continuous 
chain of lakes and numerous mountains and volcanic cones and 
craters. Either rift is divided by a transversal watershed 
into two separate hydrographic systems, one to the north, 
the other to the south. In the case of the eastern rift this 
ridge is near Lake Naiwasha, about where the Uganda 
Railway traverses the depression. In the western rift the 
watershed is formed by a veritable range of volcanic mountains 
of which some are still active at the present time. This range 
divides the chain of lakes into two distinct systems. The 
southern system includes Lakes Kivu and Tanganika; the 
northern system, Lakes Albert Edward and Albert. 
At the southern extremity of the Ruwenzori chain the 
rift bifurcates : one branch runs to the east of the chain 
and terminates at the foot of the heights which enclose the 
194 
