All were tired enough to seek their beds early. Wrapping themselves in their blankets, they were soon asleep.
Midnight came, and the camp fire slowly died away to a dull, lurid pile of red hot coals that shed a flicker of light now and then, as some charred stick flamed up and was consumed. A long, weird, wailing cry, as of some human being in dire distress, broke on the stillness of the night.
The boys awoke with a start.
"What's that?" whispered Chunky, shivering in his bed.
"Nothing," growled Ned. "What did you wake me up for?"
Once more the thrilling cry woke the echoes, wailing from rock to rock, and gathering volume, until it seemed as if there were many voices instead of only one.
The ponies sprang to their feet with snorts of fear, while the boys, little less startled, leaped from their beds with blanching faces.
The guide was already on his feet, rifle in hand.
Again the cry was repeated, this time seeming to come from directly over their heads, somewhere up the rocky side of the gulch in which they were encamped.
Even horses trained to mountain work had been known to stampede under less provocation. The frightened ponies suddenly settled back on their haunches. There was a sound of breaking leather, as the straps with which they were tethered parted, and the little animals were free.