The Burning Hills — Louis L'Amour

They had him cornered--up on a canyon rim with no way to go but down! There was a rock big as a buckboard right on the edge of the cliff. Trace Jordan bent, took hold and heaved. He felt his wound bust loose, but the rock rolled free. There was the rattle of stones behind it, then the echoing screams of a man and horse falling away into the darkness...