The whole region is underlain by nearly horizontal and undisturbed rocks of the Palaeozoic from the Devonian downward.
The town is built on high ground underlain by solid limestone, and has much natural and architectural beauty.
Much of Shaftesbury's career, increasingly so as it came near its close, is incapable of defence; but it has escaped most of his critics that his life up to the Restoration, apparently full of inconsistencies, was evidently guided by one leading principle, the determination to uphold the supremacy of parliament, a principle which, however obscured by self-interest, appears also to have underlain his whole political career.
In height; beneath these is a mass of coarse black amygdaloid, of the same thickness, underlain by a second range of basaltic pillars, from 40 to 50 ft.
Most of the plains are underlain by Cretaceous and early Tertiary shales and sandstones lying nearly unaltered and undisturbed where they were deposited, although now raised far above sea-level, particularly along the border of the Rocky Mountains where they were thrust up into foot-hills when the range itself was raised.