66 THE TANGANYIKA PROBLEM. 



and to the south of it. Further north, on Tanganyika itself, 

 these same deposits reappear and seem to cross the lake 

 diagonally, and are found in association with beds similar to 

 the Drummond series at Masswa south of Ujiji. They 

 then continue with little interruption almost to the north of 

 the lake, the tilted conglomerates and shales of the series 

 forming the crests of some of the high mountains which 

 flank Tanganyika on the east between Ujiji and Usambura. 

 The massive stratified beds which appear along the north- 

 east coast of Tanganyika are also unquestionably the same 

 series of formations as the stratified beds first seen further 

 north and east by Speke, and more latterly encountered 

 by Mr. Scott Elliot west of the Victoria Nyanza. (The 

 Karagwe series of Gregory.) 



Passing far to the west, beds which almost unquestionably 

 belong to this series have been found by Cornet on the 

 Lualaba and the upper tributaries of the Congo. 



It may be said, therefore, that there are vast aqueous 

 deposits in the African interior (the Old African sand- 

 stones), which are of enormous thickness, and which 

 there is reason to believe are actually continuous through- 

 out an area as large as the whole Australian continent (see 

 map, facing p. 75). They occur most extensively to the 

 west of the Great Central Range, and, judging from their 

 great thickness, from their obviously aqueous origin, and 

 from their vast superficial extent, it would appear probable 

 that these sandstones are to be regarded as of marine 

 origin. They are very possibly similar to the coast beds 

 of sandstone which occur in the Taru desert west of 

 Mombasa, and it is quite likely that they are actually con- 

 tinuous with the sandstones of the north of the province 

 of Mozambique, which occur in association with coal at 

 Pemba. At any rate, and beyond question they show that a 



