th of three yards from
the summit; and this portion was frozen, on the 17th July, into an icy
wall, which crumbled down as it thawed. On proceeding a little further
along the coast, some beds were observed that possessed, when newly
exposed to the air, tenacity enough to be denominated stone, but which,
under the action of water, speedily softened into a tenacious
bluish-clay.

[Sidenotes: 192, 193, 197, 198, 199] At Point Traill we were attracted
by the variegated colours of the cliff, and on landing found that they
proceeded from clays baked by the heat of a bed of bituminous-alum-shale
which had been on fire. Some parts of the earth were still warm. The
shale is of a brown colour and thin slaty structure, with an earthy
fracture. It contains many interspersed crystals of selenite; between
its lamina there is much powdery alum, mixed with sulphur, and it is
traversed by veins of brown selenite, in slender prismatic crystals.
[Sidenotes: 200, 194, 195, 196] The bed was much broken down, and hid by
the debris of the bank, but in parts it was several yards thick, and
contained layers of the wax-coloured variety of alum, named Rock-butter.
The shale is covered by a bed of stone, chiefly composed of oval
distinct concretions of a poor calcareous clay-iron stone. These
concretions have a straight cleavage in the direction of their short
axis, and are often coated by fibrous calc-sinter and calcedony. The
upper part of the cliff is clay and sand passing into a loosely cohering
sandstone. The strata are horizontal, except in the neighbourhood of
ravines, or of consumed shale, when they are often highly inclined,
apparently from partial subsidence. The debris of the cliff form
declivities, having an inclination of from fifty to eighty degrees, and
the burnt clays variously coloured, yellow, white, and deep red, give it
much the appearance of the rubbish of a brick-field. The view of the
interior, from the summit of the cliff, presents a surface slightly
varied by eminences, which swell gently to the height of fifty or sixty
feet above the general level. The soil is clayey, with a very scanty
vegetation, and there are many small lakes in the country.

[Sidenote: 201] Ten miles further on, the alum-shale forms a cliff two
hundred feet high, and presents layers of the Rock-butter about two
inches thick, with many crystals of selenite on the surfaces of the
slates. The summit of the cliff consists of a bed of marly gravel two
ya