62 THE TANGANYIKA PROBLEM. 



described are a very striking series of formations, they are 

 very similar to the sandstones and conglomerates which 

 have been found south of the Zambesi in relation to 

 the gold-bearing districts of Salisbury and Johannisburg. 

 They are probably related to the extensive sandstone 

 deposits which are said to occur north of the Zambesi 

 in conjunction with coal areas, and they may possibly 

 communicate directly with these deposits round the west 

 and south of the Nyassa region. They are also similar and 

 probably identical with the red sandstone and conglomerates 

 which occur in an enormous series of deposits in the 

 region of Tanganyika, Rukwa and Mwero. They were first 

 observed by Joseph Thompson, and have often been quite 

 erroneously spoken of as Karoo beds. 



Near Mount Waller some of the less upraised sheets of 

 sandstone bear, as I have said, above them lake deposits 

 of w T hite chalky limestone, in which there are to be found 

 the remains of the molluscs which now live in Nyassa. But 

 between Karonga and Fort Hill there are encountered, 

 resting unconformably on the old tilted red sandstones, 

 masses of grey and blue stratified rock which are obviously 

 of a different date and origin, and it was in these that 

 Drummond found the remains of ganoid fish. These 

 remains were examined by Professor Traquair and appear 

 to be the fragments of four new polypteroids closely 

 similar to several marine triassic forms. The fossil shells 

 from the same beds were also new, and were not like the 

 bivalves either of Nyassa or Tanganyika. They were 

 examined by Professor Rupert Jones and regarded as 

 probably estuarine forms. Between Nyassa and Tangan- 

 yika in this region there are also modern lake deposits 

 lying horizontally and unconformably over the tilted sand- 

 stones and the similarly tilted Drummond series. 



