THE TANGANYIKA PROBLEM. 
97 
angle into the Semliki valley. If we consider a section 
through the Albert Edward Nyanza south of the Moun- 
tains of the Moon, we have the following structural features. 
Passing over the Victoria Nyanza plateau, from east to 
west, we find that this plateau in general slightly rises 
until the eastern edge of the central depression is 
reached, when it suddenly breaks away in a fault face, 
or a succession of fault faces, above the extensive plain 
which, here, forms the flat bottom of the lake. On 
the other side of the Albert Edward Nyanza, in the 
west, there is an opposite and corresponding series of 
fault faces, and instantly beyond their crests we find 
ourselves on the Congo watershed. If now, in compari- 
son with this, we consider a section through the great 
central depression somewhat farther to the north and 
through the Mountains of the Moon, we have the 
following features. Beginning again in the east, we 
find that the Victoria plateau ends upon the flanks of 
the great range, but that where it does so the layers of 
schist of which it is composed are abruptly tilted and 
piled upon the flanks of the range. Passing still farther 
to the west, we find a succession of huge ridges of 
intruded lower rock, which project through and above 
the uptilted schists ; and on the other side of these 
intruded ridges we encounter the schists again, lying on 
their western flanks, and sloping at a very high angle 
into the floor of the Semliki valley. The surface of this 
valley, where I could examine it [at the source of the 
Semliki from the Albert Edward Nyanza, and near its 
mouth in the Albert Nyanza], was composed of little dis- 
turbed layers of modern alluvium and old lake deposits, 
containing in both situations the fossil shells of the molluscs 
which now live in the Albert and Albert Edward lakes. 
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