The cliffs of North Devon
1974; Elsevier BV; Volume: 85; Issue: 2 Linguagem: Inglês
10.1016/s0016-7878(74)80021-0
ISSN2773-0743
Autores Tópico(s)Geochemistry and Geologic Mapping
ResumoIn North Devon, the rocks are mainly of Devonian and Carboniferous age, forming the northern flank of the Hercynian synclinorium, the axis of which reaches the coast near the Cornish border. The strike of the rocks is thus east-west, and where the coast faces west, to the south of Hartland Point, the intensely folded Carboniferous beds are exposed directly to the Atlantic and are cut at right-angles to the fold-axes; this results in almost sheer flat-topped cliffs with great buttresses and reefs etched out along the bedding planes. By contrast, the coast of Exmoor runs parallel to the strike of the more massive Devonian rocks, which dip steeply but are not so closely folded; it faces the less exposed Bristol Channel, and hog's-back cliffs have developed over the scarp-edges of the beds. Between Combe Martin and Woolacombe, the slates form jagged cliffs and reefs, contrasted with the sandstones which have produced the massive Baggy Point near Croyde. The recent deposits of the Taw and Torridge estuary have been built up to face the Atlantic, but the western side of Barnstaple Bay lies under the lee of Hartland Point and its cliffs show a variety of types reflecting the detailed structure of closely folded rocks. The cliffs of North Devon are dissected by the mouths of more than fifty valleys, the majority of which are drained by waterfalls. It is suggested that the valleys which hang may be the truncated tributaries of those which are now nearer base-level.
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