Minor forms developed on steep slopes - Landforms and Geology of Granite Terrains - page 199

(b)

(c)

Figure 8.22. (b) In the Traba Massif, Galicia. (c) Flutings with a flask-shaped cross-section, Cassia City of

Rocks, Idaho, USA.

percolating along the front has to pass between rock particles so that the flow becomes diffuse.
Flutings that tend to lose definition downslope, and are therefore probably of subsurface
origin, can be seen on blocks, boulders and hillslopes in many parts of the world (e.g. Fig. 8.22b).
Some are flask-shaped in cross-section due to the induration of the rock surface (Fig. 8.22c).
In general, however, the opposite view has prevailed, finding expression for example in
Wilhelmy's (1958, p. 199) assertion that flutings in the humid tropics evolved “ auf freiliegenden
Gesteinsoberflächen ”. And some flutings in granite, like those scored on the menhir of St Uzek,
in Brittany, France (Lageat, Sellier and Twidale, 1994) are manifestly subaerial forms, having
developed during the last 5,000-5,500 years, since the erection of the monolith ( Fig. 8.23). Watson
and Pye (1985) advocate an epigene origin for Karren in Swaziland, but while stating that there is
no evidence for a subsurface origin of these (and other) minor forms, they do not discuss whether