Geology Reference
In-Depth Information
(a)
(b)
Figure 6.8. (a) A multicyclic landscape near White River, in the eastern Mpumalanga South Africa. The high
plain (X) is a remnant of an Earl y Cainozoic planation surf ace, with a residual hill in the
Bushman's Kop. It has been dissected, exposing incipient domes or bornhardts in the scarp, and
a new planation surface is forming at a lower level in the foreground. (b) Granitic hills in the val-
ley of the Umgeni River, KwaZulu Natal, South Africa, with (African - Early-Mid Tertiary) pla-
nation surface clearly visible on the skyline.
6.3 THEORIES OF ORIGIN
6.3.1
Environment
As their name suggests, inselber gs, including some bor nhardts, were at one time compared to
rocky islands. Some few authors went further and suggested that the residuals were of marine ori-
gin. Bornhardt (1900) himself initiall y entertained this view, but brief reflection sho ws that the
