460 Annals of the South African Museum. 



connected with silt-bearing streams, but after the type still known 

 in Africa as that of promiscuous pans or "vloers" described by du 

 Toit. During the stage of the upper division aridity increased ; there 

 was not sufficient moisture to segregate the lime, but the vegetation 

 that existed was still of sufficient growth to prevent the accumulation 

 of dunes. But complete desert conditions were not long delayed, for 

 during the transition period the wind-borne debris was sorted by 

 wind rolling into sand dunes. The Nyamandhlovu epoch must have 

 been one of complete desolation. Volcanism manifested itself in the 

 flow of the sheets of basalt of great extent. Dust continued to fall 

 and would be absorbed in the moving lava, but directly that flow 

 ceased in any locality and the surface hardened the wind resumed 

 its work of sorting and rolling, with the consequent formation of the 

 interbedded sandstones." It is worthy of note that the "current- 

 bedding" of the Nyamandhlovu sandstones is paralleled by similar 

 phenomena in the upper portion of the Cave Sandstone, especially 

 when it is interbedded with lava flows. 



Maufe has shown that in places where the Forest Sandstone lies 

 on granite and greenstone schist floors, the rock apparently fills up 

 valleys in the old pre-Karroo iloors, being in part banked up against 

 the sides of those valleys. 



Belgian Congo. 



The basin of the Congo forms a gigantic depression which is formed 

 of tilted and folded sedimentary rocks and schists of Palaeozoic and 

 Pre-Cambrian age resting upon Archaean granites and gneiss. At 

 the bottom of this hollow is a series of continental formations which 

 rest unconformably upon the older rocks. These lie, in the main, 

 horizontally or dip at feeble angles. They have been grouped by 

 Prof. Jules Cornet into 



3. Lubilache Beds ("Lubilash" of some authors) 



2. Lualaba Beds 



1. Kundulungu Beds. 





The Kundulungu Beds are considered by Cornet to be of "Permo- 

 Carboniferous" age; but the other two groups are thought by the 

 same author to be the equivalents of the Upper Karroo Beds of 

 South Africa, and it is these which must be considered here. 



Ball and Shaler (11)10) describe the whole series above the Kun- 

 dulungu as the Lubilache Series with a vertical thickness greater 

 than 1500 feet, while in the Kasai region their Lubilache rests on 



