356 Notices of Memoirs—Dr. G. S. Corstorphine— 
scenery—low undulating hills with a marked absence of river valleys. 
From the district of George eastward, and northward into Natal, the 
more generous rainfall renders forest vegetation possible; the granite 
tors and barren schist areas of the west are unknown, and numerous 
rivers flow seaward in deep-cut valleys. On the Natal coast the 
vegetation is still more abundant, and much of that area has an almost 
tropical character, though the geological formations are identical with 
those of the barren west coast. 
The Interior Plateau.u—The third area—the Interior Plateau—is 
the most extensive and also most varied in South Africa, showing the 
greatest diversity both of scenery and of geological constitution. 
In the Cape Colony it consists of the Karroo, with its desert 
conditions, which disappear as one passes north-eastward into the 
Orange River Colony and the Southern Transvaal, though the same 
geological horizons prevail throughout these areas. Northward, the 
High Veld of the Transvaal consists, in addition to the Karroo Beds, 
of an extensive area where the older rocks, down to the oldest formation 
of all, have been laid bare. ‘To discuss briefly the scenery of this vast 
interior plateau, it will be advantageous to deal first with the Karroo 
proper, and then the other areas built up of the rocks of the Karroo 
System. 
The ereat Karroo is one of the most characteristic features of South 
Africa, and though its scenery may not be inviting, we may remember 
that it was the Karroo fossils sent home by Andrew Geddes Bain 
which first excited keen geological interest in South Africa, an 
interest which was stimulated on other sides by the controversy over 
the marvellous basal glacial conglomerate, while it was with the 
discovery of the Karroo diamonds that South Atrica’s importance to 
the modern world began. 
The Karroo is built up of sandstones and shales which, except in 
the extreme south and west, where the lowest members of the series 
haye been involved in the folding of the mountain belt, lie horizontally. 
Basic igneous intrusions, belonging to a late period in the geological 
history of the region, are everywhere abundant throughout the Karroo 
rocks. The Karroo scenery is a true denudation landscape. The hills 
which abound are remnants carved out from a surface once much 
higher. The flat-topped hills are in the earlier stages, the pointed 
ones in the later stages, of disintegration. The interbedding of 
harder sandstones with soft shales gives the alternate cliffs and slopes 
on the hillsides, while sheets of dolerite make the more marked 
escarpments, or krantzes. 
Along the south of the Karroo, and well seen between Touws 
River and Matjesfontein, the slab-like weathering of the Glacial 
Conglomerate gives the hillsides a peculiar appearance. 
The change of scenery which occurs from about the centre of the 
Orange River Colony northward into the central Transvaal coincides. 
with the predominance of softer, more felspathic, sandstones, and the 
practically unbroken aspect of this portion of the High Veld is due to. 
the more regular and homogeneous weathering which there occurs. 
There is not the same alternation of hard and soft rocks as in the 
‘Karroo proper, and the less arid climate enables the veld grass to. 
protect the soil. 
