 Sediments eroded from these Gondwana mountains buried the Cape Fold Belt and formed the thick Beaufort Group of rocks of the Karoo basin.As the escarpment eroded, moving inland, the buried Cape Fold Mountains that had formed 150 million years earlier, were gradually re-exposed.As they were composed of erosion resistant quartzitic sandstone they remained as the less resistant overlying sediments were removed by erosion, ultimately to form the parallel formations that protrude from the coastal plain of the south and southwest Cape.