Mam Tor or the Shivering Mountain, is a huge precipice facing the east
or south-east, chiefly composed of a peculiar kind of slate, which,
although very hard before it is exposed to the air, very easily crumbles
to dust on such exposure. Hence it is perpetually wasted by the action
of the rain and snow; while the harder and larger masses of stone being
thus loosened and disengaged, necessarily fall from their positions, and
this with a rushing noise which is occasionally so loud as to be heard
at Castleton, a distance of two miles. The valley beneath is overwhelmed
with their fragments to the extent of half a mile. In many parts of the
precipice, they produce, before their descent, a cavernous appearance,
and even a romantic overhanging scenery, highly dangerous to be
approached. It is affirmed by the most intelligent of the neighboring
inhabitants, that this mountain chiefly wastes during violent storms of
snow and rain; and Mr. Martin, who published an account of Mam Tor, in
the Philosophical Transactions for 1729, affirms that the decay is not
constantly the same. He not only surveyed it closely, but ascended the
steepest part of the precipice, without tracing any other shivering in
the mountain, beside that which was occasioned by the treading of his
feet in the loose crumbled earth.