Zonality, azonality, and the coastal context - Landforms and Geology of Granite Terrains - page 301

(b)

Figure 12.7. (b) In sandstone, southern Flinders Ranges, South Australia.

(a)

Figure 12.8. (a) Orthogonal fractures in dolerite, near Umtata, Transkei, South Africa.

rocks in other areas. For instance, doughnuts and pedestal rocks occur in the southern foothills of
the Drakensberg ( Figs 12.11c and d) . One rudimentary and irregular, but nevertheless definite,
rock doughnut has been noted in dacite in the Scrubby Peak region of the southern Gawler Ranges.
Rock basins are well-developed both in limestone, where they are known as kamenitzas, and in
sandstone, as on Ayers Rock, in the southern Flinders Ranges, South Australia, and in the south-
ern Drakensberg. Tafoni are well-developed on basaltic and trachytic exposures, as in Andén
Verde, Gran Canaria, Canary Islands ( Fig. 12.12) , and are also found on sandstone boulders and
at the base of bluffs. Alveoles, though developed on granite surfaces, are at many sites better
developed on such materials as sandstone, basalt, amphibolite and siltstone, both at inland and in