 The rate of the erosion of the escarpment in the Drakensberg region is said to average per 1000 years, or per year.Because of the extensive erosion of the plateau, throughout most of the Mesozoic and Cenozoic eras, none of its surface rocks (except the Kalahari sands) are younger than 180 million years.The youngest rocks that remain, cap the plateau in Lesotho.