But Shefford, listen as he might, could not hear it. They traveled on, winding down the wonderful lane. Every once in a while Shefford lagged behind, let the others pass out of hearing, and then he listened. At last he was rewarded. Low and deep, dull and strange, with some quality to incite dread, came a roar. Thereafter, at intervals, usually at turns in the cañon, and when a faint stir of warm air fanned his cheeks, he heard the sound, growing clearer and louder. He rounded an abrupt corner to have the roar suddenly fill his ears, to see the lane extend straight to a ragged vent, and beyond that, at some distance, a dark, ragged, bulging wall, like iron. As he hurried forward he was surprised to find that the noise did not increase. Here it kept a strange uniformity of tone and volume. The others of the party passed out of the mouth of Nonnezoshe Boco in advance of Shefford, and when he reached it they were grouped upon a bank of sand. A dark-red cañon yawned before them, and through it slid the strangest river Shefford had ever seen. At first glance he imagined the strangeness consisted of the dark-red color of the water, but at the second he was not so sure. All the others, except Nas Ta Bega, eyed the river blankly, as if they did not know what to think. The roar came from round a huge bulging wall downstream. Up the cañon, half a mile, at another turn, there was a leaping rapid of dirty red-white waves and the sound of this, probably, was drowned in the unseen but nearer rapid. “This is the Grand Cañon of the Colorado,” said Shefford. “We've come out at the mouth of Nonnezoshe Boco.... And now to wait for Joe Lake!” They made camp on a dry, level sand-bar under a shelving wall. Nas Ta Bega collected a pile of driftwood to be used for fire, and then he took the mustangs back up the side cañon to find grass for them. Lassiter appeared unusually quiet, and soon passed from weary rest on the sand to deep slumber. Fay and Jane succumbed to an exhaustion that manifested itself the moment relaxation set in, and they, too, fell asleep. Shefford patrolled the long strip of sand under the wall, and watched up the river for Joe Lake. The Indian returned and went along the river, climbed over the jutting, sharp slopes that reached into the water, and passed out of sight up-stream toward the rapid.