A few miles to the west of, and running approximately parallel to, the main Rhodesian Railway from Kimberley and the Cape, there is a well defined line of hills, which is the eastern edge, and forms the scarp face of, the Kaap Plateau. Between this plateau and the railway is a belt of flat low-lying ground through which the Great Harts River runs southwards to the Vaal. In the vicinity of Taungs Station, between Warrenton and Vryburg, the scarp line is running nearly due north and south, and is only four to five miles distant from the railway; followed southwards it gets farther away from the railway and assumes a more south-westerly course. The Kaap Plateau is formed of dolomite of the Campbell Rand Series of the Transvaal System, corresponding to the dolomite in the Transvaal. The formation dips gently to the west at angles of 2–3°. Along the escarpment the dolomite rests conformably on dolomite shales, the latter frequently forming a series of terraces from the base of the plateau upwards. Lying unconformably against the dolomite to the east are the Lower Karroo Beds, which are largely concealed by secondary limestone and the recent alluvium of the Harts River basin.