That is all.

Some pieces of skin hanging around the walls, and the bones of animals strewed over the ground outside, give a clue to the kind of food upon which the inhabitants of the hut may have subsisted.

Hunters they must have been.

That will be your natural conjecture.
But how did they get into this valley, and how got they out of it?
Of course, like yourself, they descended into it, and then ascended out again, by means of a rope-ladder.
That would be the explanation at which you would arrive; and it would be a satisfactory one, but for a circumstance that just now comes under your observation.
Scanning the _facade_ of the cliff, your eye is arrested by a singular appearance.

You perceive a serried line, or rather a series of serried lines, running from the base in a vertical direction.