Yet from time to time, as he rested, he saw the massive red walls growing higher and wilder, more looming and broken.

He made note of the fact that he was turning and climbing.

The sage and thickets of oak and brakes of alder gave place to pinyon pine growing out of rocky soil.
Suddenly a low, dull murmur assailed his ears.

At first he thought it was thunder, then the slipping of a weathered slope of rock.

But it was incessant, and as he progressed it filled out deeper and from a murmur changed into a soft roar.
"Falling water," he said.