The differential erosion of the Unkar Group left resistant beds of the Cardenas Basalt and Shinumo Quartzite as topographic highs, ancient monadnocks, that are now buried by sandstones, shales, and conglomerates of the Tapeats Sandstone.
22.
Gabbro and diabase structures of the Duluth Complex trend generally from southwest to northeast, and the differential erosion has left a series of ridges comprising these harder mafic rocks rising from the softer sedimentary rocks of the Rove Formation.
23.
Though this surface is typically a plane, differential erosion of the tilted strata of the Unkar Group left resistant beds of the Cardenas Basalt and Shinumo Quartzite as ancient hills, called monadnocks, that are up to high.
24.
Without Middlesboro crater, it would have been difficult for packhorses to navigate this gap, formed by differential erosion along one of the subsequent cross faults, and improbable that wagon roads would have been constructed at an early date.
25.
Differential erosion has resulted in steep hills around the lake and peninsulas within it, which divide the estuarine ecosystem into five long, deep channels in the north half of the lake and a number of bays in the south.
26.
It is from below, on the plain, viewing the steep slopes and sharply-etched skyline that the area appears mountainous; from the plateau the land appears merely hilly, and in fact it is rather flat apart from the effects of differential erosion.
27.
None of the single aforementioned methodologies is decisive on determining 3D fold growth and a combination of methodologies should be used, because similar morphology can be produced by limb rotation and differential erosion across strata of varying competency, which do not implicate three-dimensional fold growth.
28.
Many of this region's lakes are located in depressions formed by the differential erosion of tilted layers of bedded rock of the Canadian Shield; the crevasses thereby formed have filled with water to create many of the thousands of lakes and swamps of the Superior National Forest.
29.
The coast is framed by bedrock, left during the formation of the Appalachian mountains, and the irregular shape of the coast ( characteristic of much of the New England coast, with the exception of Cape Cod and the islands ) is attributed to differential erosion of the underlying rock layer.
30.
Between these two escarpments the anticline has been subject to differential erosion so that geologically distinct areas of hills and vales lie in roughly concentric circles towards the centre; these comprise the Greensand Ridge, most prominent on the north side of the Weald, where it includes Leith Hill, the highest hill in south-east England, the low-lying clay vales of the Low Weald, formed of less resistant Weald Clay, and finally the more highly resistant sandstones of the High Weald at the centre of the anticline, whose elevated forest ridge includes most notably Ashdown Forest.
