Minor forms developed on steep slopes - Landforms and Geology of Granite Terrains - page 181

coatings accumulated on steep slopes of residual hills and boulders are scratched by branches,
twigs and even by needle-like leaves of such plants as spinifex ( Triodia spp .) moved by the wind
and producing arcuate and concentric markings (Fig. 8.10c).

8.2 FRETTED BASAL SLOPES AND OTHER VARIANTS

Though lacking flared slopes as such, many boulders and some inselbergs display basal fretting:
the lower sections of the steep bounding slopes of hills and the flanks of blocks and boulders are,
to a greater or lesser degree, notched and overhanging (Fig. 8.11) . The walls of the concavities
are rough, not smooth and regular, as are flared slopes. This, in many instances, reflects the
texture of the bedrock, the fretting being especially well-developed in coarsely crystalline or
porphyritic granite. Nevertheless, and despite morphological differences in detail, the fretting

(a)

(b)

Figure 8.11. Basal fretting of (a) residual boulder at Devil's Marbles, Northern Territory; (b) slope of

Chilpuddie Hill, northwestern Eyre Peninsula, South Australia.