Directly in front, extending to the very edge, stretched a solid wall of rock.

My eyes sank to the shelf on which I stood.

Lying close against the sheer cliff was the root of a tree, its trunk, perhaps a foot or more in diameter, stretching over the abyss, whose depth I durst not guess.

I stooped cautiously, my heart throbbing, and ran my fingers along the bark.
"Oak," I announced soberly, "and feels solid and strong.

No doubt those Indians must cross here, but it is a bridge to rack the nerves." "Will you adventure the passage ?" questioned Cairnes, striving to peer across my shoulder.