|
In the south-west of Cornwall the ancient marine platform, of Pliocene age, rises to a height of 430 feet above the sea, and its upper limit is a steep slope, often a bluff. In the same area the uplift of this platform has led to the deepening and cutting-back of the larger valleys, giving rise to a steepening of slopes in the lower part of the banks. This feature becomes less marked as the valleys are ascended, and in the case of the River Camel it disappears altogether at a distance of 22 miles from the sea. Above this point the river-banks and also the ground above them, now much over 430 feet high, retain in the main the same angle of slope as that which they had in Pliocene times, though of course they have been lowered to some extent by denudation.
The retention of the characters of the older scenery is naturally most marked in the still higher grounds about the watershed of the River Camel, part of which includes Davidstow Moor. This moor also forms the gathering-ground of the Inney (a tributary of the Tamar); and, if the watershed be crossed and the valley of this river descended, the features just noted will be met with in reverse order, as that area is approached within which the denudation of post-Pliocene times has produced its most characteristic effects.
Of the older topography thus partly destroyed by post-Pliocene denudation, the most striking feature in the higher part of the
...
This 250-word extract was created in the absence of an abstract.
