CENTRAL UR1MI. 715 



rows became enlarged, the -water fritted away their banks, and conveyed the 

 earth to lower levels, through which it wore away a channel first through the 

 soil, and lastly through the rock itself, which you may see if you but descend 

 to the bottom of that basin. You will there behold, worn through the solid 

 rock, a fissure some fifty feet in depth ; and, as you look on that, you will 

 have an idea of the power and force of tropical rains. It is through that 

 channel that the soil, robbed from these rocks, has been carried away towards 

 the Nyanza to fill its depths, and in time make dry land of it.' You may 

 ask how came these once solid rocks, which are now but skeletons of hills and 

 stony heaps, to be thus split into so many fragments. Have you never seen 

 the effect of water thrown upon lime ? These solid rocks have been broken 

 and peeled in an almost similar manner. The tropical sun heated the surface 

 of these rocks to an intense degree, and the cold rain then falling caused the 

 rocks to split and peel as we now see them. 



" Such is really the geological history of this country. Ridge after 

 ridge, basin after basin, from Western Ugogo to the Nyanza, tell the same 

 tale ; but it is not until we enter Central Urimi that we begin to marvel at 

 the violence of the process by which Nature has thus transformed the face 

 of the land. For here the perennial springs and rivulets first unite and form 

 rivers, after collecting and absorbing the moisture from the watershed, and 

 these rivers, though but gentle streams during the dry season, become for- 

 midable during the rains. It is in Central Urimi that the Nile levies its ear- 

 liest tribute upon Equatorial Africa ; and if you look upon the map and draw 

 a line east from the altitude of Ujiji to longitude 35° east, you will strike 

 upon the sources of the Leewumbu, the extreme southern feeder of the Vic- 

 toria Nyanza. In Iramba, between Mgongo Tembo and Mombiti, we came 

 upon what must have been in former times an arm of the Victoria Nyanza. 

 It is called the Lumamberri Plain, after a river of that name, and is about 

 forty miles in width. Its altitude is about 3,775 feet above the sea, and but 

 a few feet above the Victoria Nyanza. We were fortunate in crossing the 

 broad shallow stream in the dry season, for during the masika, or rainy sea- 

 son, the plain is converted into a wide lake. 



" The Leewumbu River, after a course of one hundred and seventy 

 miles, becomes known in Usukuma as the Monangah River. After another 

 run of one hundred miles, it is converted into the Shimeeyu, under which 

 name it enters the Victoria east of this port of Kagehyi. Roughly, the Shi- 

 meeyu may be said to have a length of three hundred and fifty miles. After 

 penetrating the forest and jungle west of the Lumamberri, we enter Usu- 

 kuma — a country thickly-peopled, and rich in cattle. It is a series of rolling 

 plains, with here and there, far apart, a chain of jagged hills. The descent 

 to the lake is so gradual that I expect to find upon sounding it, as I intend 

 to do, that though it covers a vast area, it is very shallow. 



