They resolved to carry through what they had begun; and at length commenced to ascend, Basil taking the lead.
It was severe climbing withal; and now and again they had to pull themselves up by laying hold of branches and roots.

They noticed that _there was a trail_, which they followed upward.

No doubt the big-horns, or some other animals, had made this trail as they passed up and down--though it was only distinguishable by a slight discoloration upon the rocks, and by the earth being packed firmer in some places, as if by hoofs or feet.

A little better than half-way up the boys observed a fissure, like the entrance of a cave, on one side of the ravine and close to the trail.

Around this the earthy colour of the rocks, the absence of herbage, and the paddled appearance of the soil, suggested the idea that some animal made its den there.