Our walk round the little lake, however, resulted in a disappointment which staggered us for the moment. There was no outlet. The lake was land-locked; the one insignificant rivulet we found running into it being evidently no more than enough to counterbalance the daily evaporation.
"Well," remarked Dick, after a long pause, "there is one thing sure: the Pueblos never built a flume and dug that big, long ditch to carry this trifling amount of water. This lake, after all, was not the source of supply, as we were supposing. It was a reservoir, perhaps, but nothing more. The real source was somewhere higher up."
If Dick was right—and there could be hardly a doubt that he was—the most promising direction in which to continue our search would be on the west side of the lake, whence the little rivulet came down. An examination of the ravine in which the stream ran showed evidence that it had at one time carried much more water than at present, so, with hopes renewed, we set off at once along its steep, stony bed.
The country on that side was very rough and precipitous, and the ravine itself, reasonably wide at first, became narrower and narrower, and its sides more and more lofty, until presently it became so contracted that we might have imagined ourselves to be walking up a very narrow lane with rows of ten-story houses on either side. The sky above us was a mere ribbon of blue.
After climbing upward for about half a mile, we began to catch occasional glimpses ahead of us of a frowning cliff which bade fair to bar our further progress altogether, and we were beginning to wonder whether we had not chosen the wrong ravine after all, when suddenly, with one accord, we all stopped short and cocked our ears. There was a sound of running water somewhere close by!
There was a bend in the gorge just here, and we could not see ahead, but the instant we detected the sound of water, Dick, with a shout, sprang forward, and with me close on his heels and the short-legged Pedro some distance in the rear, dashed up the bed of the ravine and round the corner.
What a wonderful sight met our gaze! Out of the great cliff I mentioned just now there came roaring down a magnificent stream, which, falling into a deep pool it had worn for itself in the rocks, went boiling and foaming off through a second ravine to the right—a fine thing to see!
But what was finer, and infinitely more interesting, was the original Pueblo head-gate, so set in the narrow gorge in which we stood that the water, which, if left to itself, would have flowed down our ravine, was forced to run off through the other channel.
It was a remarkable piece of work for such a primitive people to have performed, considering especially the very inferior tools they had to do it with. The walls of the gorge came together at this point in such a manner that they were not more than five feet apart and were so straight-up-and-down that they looked as though they had been trimmed by hand—as possibly they had been to some extent. Taking advantage of this narrow gap, the Pueblos had cut a deep groove in the rocks on either side of the ravine, and in these grooves they had set up on end a great flat stone about five feet high and three inches thick—it must have weighed a thousand pounds or more.
Against this stone head-gate, on its inner side, the water stood four feet deep, and it was obvious that when the gate was raised the flood would go raging down the gorge we had just ascended into the little lake below, leaving the bed in which it now ran high and dry.