Minor forms developed on steep slopes - Landforms and Geology of Granite Terrains - page 200

Figure 8.23. Menhir at St Uzek, northern Brittany, France, showing flutings developed since erection. The

basin (X) shows that the vertical face on which it is located was originally horizontal.

the residuals that are host to the features are two-stage forms or not. If they are, then the surfaces
on which the Karren occur were once at the weathering front.

8.6.4 Inversion
At several sites, but especially well-developed at Wave Rock, Western Australia, and at Turtle,
Pildappa and Yarwondutta rocks, on northwestern Eyre Peninsula, Southern Australia are former
gutters that are now ribs: there has been local inversion of relief ( Fig. 8.10a and Fig. 8.24) . Most
gutters draining from the flattish upper surfaces of hills continue down the steeper marginal slopes
as channels scored in the lower marginal slopes (Twidale, 1962). On the very steep slopes - even
those that are overhanging - surface tension allows seepages to adhere to the channel floor, though
higher velocity flows separate from the bedrock, in places causing minor plunge pools to form in
the channel floor (Figs 8.10a and b) . Some gutters drain debris-filled vegetated basins. They carry
blue-green algae (on Eyre Peninsula, Calothrix spp .), which coat slopes and channel floors.
Though thin, these coatings are, on one interpretation, evidently enough to protect the bedrock,
and on overhanging slopes facing north or northwest later flows have differentially eroded the
unprotected zones adjacent to the original flutings, leaving the old channel floors in relief, as ribs.
There are complications, for the later lateral channels are not coated with algal remains.