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MESSES. A. R. ANDREW AND T. E. G. BAILEY [May IO,IO, 



again, no true limestone is found ; but the upper mudstones are 

 distinctly calcareous, and are probably in part equivalent to the 

 calcareous beds of the north. 



Detailed descriptions of the isolated patches of Karroo which occur 

 in Northern Nyasaland will now be presented under the following 

 heads : — 



(A) Nkana Area. 



(B) Kasante, Lufira, and Lower Rukuru Area. 



(C) Mwapo and Sere River Area. 



(D) Western Nyika Area. 



(E) Mount Waller Area. 



(F) Henga Area. 



The Karroo and the recent 

 Tuffs of the Nkana Area. 



(A) Nkana Area. — This is a low-lying district some 20 square 

 miles in extent, and situated at the northern extremity of the 



Nyasaland Protecto- 

 Fig. 3. rate. It is bounded 



on the south and east 

 by a hilly region, 

 which forms a very 

 irregular sloping plat- 

 form between the high 

 mountains on the 

 west and the low 

 sandy plains fringing 

 the lake. The north- 

 ern limit is denned by 

 the Songwe River, 

 the international 



boundary between 

 German East Africa 

 and Xyasaland. On 

 the west lie mountain- 

 ranges, a prolonga- 

 tion of the Msuko 

 Hills. The Nkana 

 area is practically 

 identical with the 

 drainage -area of the 

 Makey a Valley. That 

 valley has, in fact, 

 been excavated out 

 of the comparatively 

 soft Karroo rocks 

 which have here been 

 trough - faulted into 

 the surrounding 



gneiss. The broad 

 Makeya Valley offers a striking contrast to the deep V-shaped 

 valleys of the rivers, commensurable in size, but confined to the hard 

 gneisses and crystalline schists of the neighbouring region. 



WSSM strJped Grits and Concretions. 



Ill i I Limestone Group. 



Brzz^rj Green Shales and Purple Grit 



l.-u lpprr Sandstones. 



iShale Group. 



\Lower Sandstones: 



Alluvium 



1^ AA 1 T,,f t \ 



Faults. 



[Scale: 1 inch 

 = 3 Miles.'] 



