"Whatever it was," he remarked, "it doesn't mean to repeat the act. But all the same, Bob, I've got a hunch we've found the place, and that Echo Cave lies far up yonder in that beetling cliff."
"It's a fierce reach up there," remarked Bob, as he scanned the height. "How under the sun d'ye suppose that old professor could ever get up and down? Too far for him to have a rope ladder; and even if he had, how could he reach the place at first? Frank, all the way up, I can't see the first sign of any rock shelves, where ladders might have rested long ago."
"That's so," replied the other, reflectively. "The face of the cliff is as even and smooth as a floor. Nobody would ever look to find a cluster of cliff dwellers' homes up there; that is, nobody but a man like Professor Oswald, who has made a life study of such things, and knows all the indications. But something tells me we're pretty near the end of our long trail. The only question now is, how can we get in touch with the hermit of Echo Cave?"
As night settled down the two boys returned to the fire, still perplexed.[Contents]
[CHAPTER XVIII]
FINDING A WAY UP
That night they kept no fire going. Frank seemed to think it best that they remain quiet, so as not to announce their presence in the neighborhood. Though for that matter, it would seem that if any one were perched aloft in one of those slits in the face of the cliff, that represented the windows of the cave dwellings, the entire canyon below must be spread out like a book.
Nothing happened to disturb them. Once Frank thought he heard a distant shout, and this excited his curiosity not a little. According to what Charley Moi said they were now in a neighborhood where ordinary tourists never visited.