O04 Notices of Memoirs—Dr. G. S. Corstorphine— 
Karroo, for we find its deposits in the Breede River Valley, south of 
the Langebergen. It seems likely that the lacustrine conditions 
prevailed longest in the east, north-east, and north, for it is only there 
that the Stormberg Beds, the youngest division of the Karroo System, 
are found, and we have no reason to believe that their absence in the 
south and west is due to denudation. 
The disappearance of the Karroo Lake was probably accompanied 
by, if not actually due to, the upheaval of the only true mountain 
chains which characterise South African scenery, and it was doubtless 
during the same period of disturbance that the enormous volcanic 
activity now represented by the lavas of the Drakensbergen had its 
origin. The fossil evidence shows that this final upheaval most 
probably occurred in Jurassic times. 
The submergences which occurred later affected only the coastal 
belt of the country, and are represented by the relatively smail 
patches of Cretaceous rocks occurring in Cape Colony, Natal, and 
Zululand, and the strip of Tertiary beds on the coast of the last-named 
province. Throughout the greater extent of Secondary and Tertiary 
times the larger part of South Africa has been a land surface, and it is 
no wonder that its landscape should, to such an extent, show features 
due to denudation. 
The present scenery has originated from the accretion of remnants 
of successive formations, each to a large extent formed by the 
disintegration of such portions of its predecessors as could be affected 
by the complex agents of denudation, while the sum-total as presented 
by the land of to-day is undergoing continuous modification by the 
denuding agents now at work. 
For the present purpose South Africa may be regarded as falling 
into three zones—the Coastal Zone, the Mountain Belt, and the 
Interior Plateau. 
The Mountain Belt—The Mountain Belt is well developed in the 
west and south, and, as it is the essential feature in the structure of 
South Africa, I shall deal with it first. It embraces all the mountains 
which trend north and south on the western border of the Karroo 
and the various ranges which run east from Hex River Pass to the 
vicinity of Algoa Bay. This extended area consists of a series of true 
mountain chains, showing as much intricacy of structure as the Alps 
of Central Europe. The most conspicuous geological component is 
the Table Mountain Series, but the two higher members of the Cape 
System also play a part, while on the internal boundary of this zone 
the lower beds of the Karroo System are included in the mountain 
folds. Sections showing true mountain structure are to be seen in 
such places as Mitchell’s Pass, Hex River Pass, and in the various 
passes and river gorges which cut the mountain chains from north to 
south, such as the Montagu and Prince Alfred’s Pass over the 
Langebergen and the Gamka River Poort and the Zwartberg Pass 
through the Zwartebergen. Mountain scenery of the wildest and 
srandest type is to be seen among the Zwartebergen, the Langebergen, 
and the intervening ranges. Denudation has played a large part in 
the production of “the present scenery, for the summits of all these © 
ranges consist of Table Mountain quartzites, the geologically higher 
