As a Cambrian fauna has not been found in South Africa, where the oldest known fauna is of Devonian age and occurs in beds some 5,000 feet above an unconformity of great importance in the structure of the southern part of the subcontinent, the upper limit of the Precambrian is chosen arbitrarily.
In the literature such terms as Silurian, Ordovician, Cambrian are to be found, but their use is unwarranted, for no fossils from the rocks so designated have been described or determined.
The most important difference of opinion concerning the intercorrelation of South African rocks affecting this question is about the contemporaneity or otherwise of the Table Mountain series in the south, and the Waterberg system in the north. In this article the assumptions will be made that these formations are of different ages, and that the Waterberg system is the older . . .