Projecture

I now found myself on the projecture of a rock: above and below, the hill-side was nearly perpendicular. Opposite, at the distance of fifteen or twenty yards, was a similar ascent: at the bottom was a glen, cold, narrow, and obscure. The projecture, which served as a kind of vestibule to the cave, was connected with a ledge, by which, though not without peril and toil, I was conducted to the summit.