Geoscience Reference
In-Depth Information
Godolphin, Carnmenellis and St Austell granite areas, while they are common weath-
ering features on Bodmin Moor and Dartmoor. This probably reflects a difference in
the weathering and uplift histories of the different granite bodies.
FIG
53.
The Isles of Scilly, looking east towards Bryher, Tresco and St Martins. (Copy-
right Dae Sasitorn & Adrian Warren/www.lastrefuge.co.uk)
The Land's End granite (
A2
) forms the bedrock of most of the far southwestern
peninsula, which is largely ringed by cliffs. To the east of the granite, St Ives Bay
on the north coast and Mount's Bay on the south coast show how much more readily
eroded the Devonian killas is in comparison. Along the north coast of the Land's End
peninsula, the killas is preserved as a screen of land, rarely more than a kilometre in
width, but clearly showing distinctive layering, as seen at Gurnard's Head (
a3
; Fig.
56). Present coastal erosion may have been slowed at this point by the greater strength
of the Devonian where it has been altered close to the granite. Just north of Land's End
point, Whitesands Bay (
a1
) is one of the only sandy bays to face the open sea to the
west. The bay lacks any significant stream system that could have supplied sand to the
beach, so it seems most likely that the sand has been carried into this bay by the storms
which so often attack this exposed coast.
