Zonality, azonality, and the coastal context - Landforms and Geology of Granite Terrains - page 312

(a)

(b)

Figure 12.18. (a) Nubbin and (b) bornhardt forming islands in the Glennie Group, at Wilsons Promontory,

Victoria.

than the regolith that retains the moisture that produces rapid weathering of the surrounding areas.
The fonts of Shag Point, near Moeraki, South Island, New Zealand ( Fig. 12.20d) , on the other
hand, are indurated with limonite; their evolution is not yet known. The runnels found on some
limestone ramps on the west coast of Eyre Peninsula in a zone seaward of an inner zone of pot-
holed ramp or platform are, like their terrestrial counterparts, sculpted by running water, but here
by the wash and backwash of breaking waves.
Other forms common to terrestrial and coastal sites have, however, evolved in different ways
and are thus convergent forms. Plinths provide a good example. As described in Chapter 9, plinths
on inland granitic residuals are due to the umbrella effect of the block or boulder that rests or