If the mountains had been gloomy and sinister to the view while riding along the base of them, the northern entrance to Grizzly Pass itself threw a damper over the spirit of even Coyote Pete, who had hitherto larked about and displayed a great fund of high spirits. The dark wall of the cañon rose perpendicularly to a height of more than a hundred feet on the right side of the rough trail. At the other hand was a deep and dark abyss at the bottom of which a hidden river roared. Beyond the formidable pit reared another frowning rampart of sheer rock. Deep down could be heard the murmuring of water.
"That's the overflow from the big dam," explained Walter Phelps, pointing over into the sonorous depths.
"The dam is up in this direction, then?" inquired Ralph.
"Yes, it is located in a small cañon, off to the right of the pass. I'll show you the place when we reach it."
For some time they rode on without a word. The deep gloom and oppressive silence was not encouraging to conversation. The sound of a stone dislodged by a pony's hoof in that dismal place caused several of the party to give a nervous start more than once.
Suddenly the right-hand wall of the cañon opened out—as they rounded a sharp promontory of rock—and another deep chasm cut abruptly into Grizzly Pass almost at right angles. The deep rift which this caused across the trail had been bridged by a span of rough logs which crossed the intersecting cañon at a height of fully three hundred feet. A scene of wilder and more impressive grandeur than the cañon presented at the point they had now reached not one of the party had ever beheld. Even a whisper went echoing and reverberating among the gloomy rocks in startling contrast to the brooding silence of the spot.
The frowning black walls, the melancholy-looking trees clinging to the almost perpendicular walls, the bottomless chasm, and the deep dusk of late afternoon, all combined to make it the most oppressive scene into which any of the boys had ever penetrated.
They had reached the bridge and the feet of the Mexican guide's horse were upon it, when from behind them there came a sudden startling sound.
The loud report of a rifle, followed by another and another, re-echoed behind them seemingly high up among the rocks.