﻿20 4 MESSES. A. E. ANDBEW AND T. E. G. BAILEI [May I9IO, 



(4) Towards the bottom the Green Shale and Purple Grit Group 

 consists of a set of red-brown shaly inudstones : then follow fine- 

 .grained purple grits and, finally, grey-green shales. Thin bands of 

 limestone occur in the grits, and calcareous concretions are frequent 

 in the shaly mudstones. 



(5) The Limestone Group comprises argillaceous limestones, mag- 

 nesian limestones, and shales. None of the individual bands of this 

 series is very thick, 5 feet being perhaps a maximum. 



The limestones form a conspicuous feature rising about 80 feet 

 above the floor of the Makeya Valley, running in a north-and-south 

 direction for a distance of 4 or 5 miles. Near Makeya's village, in 

 the bed of the Makeya River where the latter bifurcates, there are 

 two small outcrops of dark -grey shale lying close together, which 

 contain numerous casts of freshwater lamellibranchs (PaJwomutela 

 oblonga), and also fish-scales (Colobodus africanus) similar to those 

 discovered by Prof. Drummond at Maramura, near Karonga, some 

 20 to 30 miles away to the south (see Appendices II & III). 



(6) The Striped Grits with concretions are very crumbly and 

 non-coherent. They contain, however, occasional compact bands of 

 sandstone and frequent calcareous concretions. The group is of 

 considerable thickness, but is largely masked by the alluvium of the 

 Makeya River. The present course of the Makeya has doubtless 

 been determined by the soft and non-coherent character of these 

 grits. 



(R) Kasante, Lufira, and Lower liukuru Area. — The 

 hilly platform of gneiss lying south and east of Nkana drops some- 

 what abruptly into the wide plain bordering Lake Nyasa. The 

 Karroo rocks occur along the junction of the hills with this plain, 

 and form a fringe running roughly north and south — at first narrow 

 and broken, but widening out southwards towards the Northern 

 liukuru River (fig. 2, p. 193). The Karroo is thus flanked on the 

 west by crystalline rocks, from which it is separated by lines of fault, 

 and is overlain unconformably on the east by recent gravels, sands, 

 and clays. 



The northernmost exposure lies a little to the west of Kasante 

 village, where the river of that name emerges from its gorge 

 to flow tranquilly across the coastal plains of the lake. The 

 Karroo here forms a small block some 3 miles square, inset into 

 the edge of the crystalline region, and bounded on three sides by 

 lines of fault. The beds dip, at angles varying from 10° to 30°, in 

 a south-easterly direction. They can be grouped into an Upper 

 Division, consisting of easily weathered yellow and reddish felspathic 

 grits and sandstones ; a Middle Division, consisting from the base 

 upwards of dark-grey argillaceous grits with large flakes of white 

 mica, then coal and coaly shale, followed by greenish lumpy shales 

 with pale bands of mudstone containing ill-preserved stem-like 

 impressions ; and a Lower Division formed of white or cream- 

 coloured sandstones, near the top of which occur curiously shaped 



