He rode up under them wonderingly, pleased to feast his eyes upon the natural colour of rock and earth, and eager, with what knowledge of geology he had, to read the story they told.
This story, as far as the history of the earth was concerned, was soon told; the cliffs were of gray carboniferous limestone.

Caius became interested in the beauty of their colouring.

Blue and red clay had washed down upon them in streaks and patches; where certain faults in the rock occurred, and bars of iron-yielding stone were seen, the rust had washed down also, so that upon flat facets and concave and convex surfaces a great variety of colour and tint, and light and shade, was produced.
He could not proceed immediately at the base of the cliffs, for in their shelter the snow had drifted deep.

He was soon obliged to keep to the beaten track, which here ran about a quarter of a mile distant from the rock.

Walking his horse, and looking up as he went, his attention was arrested by perceiving that a whitish stain on a smooth dark facet of the rock assumed the appearance of a white angel in the act of alighting from aerial flight.