Page:South African Geology - Schwarz - 1912.djvu/200

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SOUTH AFRICAN GEOLOGY

morphosed Waterberg Sandstone, there must have been a vast time interval between the deposition of the two sediments. In the south the Dwyka Conglomerate is separated from the Table Mountain Sandstone by the Bokkeveld and Witteberg, which represent in Europe the whole of the Devonian and Carboniferous times. This, however, is not sufficient time to account for the Dwyka Conglomerate resting on the Waterberg on the north, for the Waterberg would have had to be deeply buried for the compacting and metamorphism to go on. It would have had to be subjected to mountain-building forces, to be wrinkled up into the folds it now exhibits; the overlying strata would have had to be removed, and only then could the glaciers have flowed over the floor of altered Waterberg Sandstone, and carried boulders down into the till. As a matter of fact, similar boulders of Waterberg Sandstone are found in the Table Mountain Sandstone in Table Mountain.

Neo-Afric Group

The Karroo Formation

The Karroo Beds of the Transvaal begin with the Dwyka Conglomerate, which is found over the southeast of the province covering the Waterberg and Dolomite Series. The underlying beds are often beautifully striated, as at Balmoral. Farther east, in the Vryheid district, the granite and schists of the Swaziland Beds are striated. The whole of the Dwyka Conglomerate in the Transvaal, and in Natal also, is a terrestrial moraine, and hence these are neither the lower nor the upper shales that are found in the south of the Cape Colony. At Vereeniging the conglomerate is penetrated by roots