Chapter VII. 



ranges down to tlieir liigli 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 (JOO to 700 feet below the average 

 level of Usanda, and contaiuino; the Ijasins of Lake Albert 

 and of Lake Albert Edward with its northern prolongation, 

 Lake Dweru or Ruisamba. 



Tlie whole of this depression forms simplv a portion of 

 the western "rift." The "rifts" consist of two gigantic 

 trenches, from 20 to 50 miles in width, rurmino- nearlv 

 parallel to one another, with an interval of G' 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, Ijeyonfl wliich 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 l)v a transversal watershed 

 into two separate hydrographic systems, one to the north, 

 the otlier to the south. In tlie case of the eastern rift this 

 ridee is near Lake Naiwasha, about where the Uiranda 

 Railway traverses the depression. In the Avestern rift the 

 watershed is formed by a veritable range of volcanic mountains 

 of Avhicli 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 Tanganlka ; the 

 northern system, Lakes Albert Edward and Albert. 



At the southern extremity of the Ruwenzori chain tlie 

 rift bifurcates : one branch luns to the east of the chain 

 and terminates at the foot of the heights wliich enclose the 



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