And facing west, I came, at last, to understand perfectly the meaning of the breaks in the Siwash.

They were nothing more than ravines that headed up on the slopes and ran down, getting steeper and steeper, though scarcely wider, to break into the canyon.

Knife-crested ridges rolled westward, wave on wave, like the billows of a sea.

I appreciated that these breaks were, at their sources, little washes easy to jump across, and at their mouths a mile deep and impassable.

Huge pine trees shaded these gullies, to give way to the gray growth of stunted oak, which in turn merged into the dark green of pinyon.