Page:South African Geology - Schwarz - 1912.djvu/97

, which have been carved by the rivers as the land gradually rose to 6600 ft. The rise was not continuous, however; after the first 2000-ft. elevation, the land stopped rising and a great peneplain was eroded at this level, now 4000 ft. above sea level. The next resting stage was at 2500 ft. above present sea level, and succeeding levels are at 1500 ft., 600 ft., sea level, and 600 feet below sea level.

The only place where these have been studied in detail is in Cape Colony. The 4000-ft. peneplain is still found in the mountainous country between Uniondale, Oudtshoorn, and Prince Albert. Remains of the gravel-capped plains at the last-named place show that the 4000-ft. peneplain probably extended to the escarpment of the Nieuweveld Mountains, for the isolated hills of the Karroo between rise to this level. The 4000-ft. peneplain was submerged, and covered with Cretaceous deposits which were subsequently let down into fault pits. It then rose again to the old level and all the loose Cretaceous deposits, except in a few isolated cases, were swept away, and the Cretaceous deposits, themselves lying in the fault pits, were cut off on top to the 4000-ft. level. There are consequently two peneplains at 4000 ft. above present sea level, which are respectively pre-Cretaceous and post-Cretaceous. The 2500-ft. level is only markedly shown in the native territories east of the Kei River, but remains of it are seen in the hills about Grahamstown for instance, and farther north in the Queenstown Division. In the Transkei the great post-cart road to Natal is carried on this level, descending every now and again the steep gorges of the rivers that have cut into it. Most of the gravel and sand of the original peneplain have been removed, but in isolated cases, as at