That was one thing; and another was that they saw no grade stakes anywhere along the way. Again, Dick, who had a quick ear for unusual sounds, thought he could hear, far away to their left, a tiny, insect-like clicking that would have been set down at once, in other circumstances, as a distance-diminished chatter of air-drills burrowing in solid rock. Dick told himself scoffingly that of course it couldn’t possibly be air-drills, and he was wondering, as they hurried along, what high-altitude insect it could be that kept up such an incessant chink-a-chink-a-chink.
It was not until after they had measured an exceedingly crooked course of perhaps half a mile among the sandstone buttes that they came to a stream which they took to be Yellow Dog Creek, inasmuch as it wasn’t nearly big enough to be the Tourmaline. Up the stream the ditch-cleaner led the way at his space-devouring stride, and in a short time the boys saw that they were approaching the head of the valley, if a many-pointed star could be said to have a head.
This conclusion apparently verified itself when they presently plunged into a canyon, the gash in the mountain through which the creek entered the valley. Up this canyon their guide hurried them, slackening his pace only after two or three twists in the gorge had shut off any view of the rear.
It was along about this time that Dick began to grow curious.
“Say, Jonesy; what canyon is this?” he asked.
“Echo Canyon,” the guide flung back over his shoulder. Then he halted abruptly. “Listen,” he commanded.
Distinctly—so clearly that they could have sworn that the source of it couldn’t possibly be more than a mile away at the farthest, came the chooka-chooka-chooka of a locomotive laboring with a heavy train. Their guide’s grin showed a bad set of teeth.
“That’s why it’s called ‘Echo’,” he explained. “You wouldn’t reckon you could hear them O. C. trains ’way down yonder in the lower canyon, would you now? It’s six mile in a bee line, if it’s a foot.”
It appeared grossly unbelievable, to be sure, but seemingly the fact remained. They could hear the laboring engine; and, in the nature of things, it couldn’t be any nearer than William Jones had declared it to be.