"Let's go over that ground again," remarked Bob.
"Now you're referring to what was said about the funny old stone dwellings of the cliff dwellers, who used to live there centuries ago," remarked Frank.
"And he's right, too," declared the ranchman. "I get the point Bob makes. It was about these wonderful people that Uncle Felix was so deeply interested, and he made up his mind to shut himself away from all the world, just to study up their history, as left in the holes in the rock."
"And it would seem to follow, then," said Bob, readily, "that he will be found located in one of those series of terraces where these holes are discovered. I notice that there are a number of these villages connected with the map of the Grand Canyon; but the chances are your Uncle Felix wouldn't take up with any where tourist travel was common."
"Now, that sounds all right," admitted Frank. "In the first place he would have been heard from long ago, if tourists ran across him; because they always talk, and send their accounts to be published in the papers."
"Besides, these scientific men hate to be watched when they're wrapped up in work like this. I've known a couple back in Old Kentucky," Bob went on.
"According to your idea, then," said the Colonel, nodding approvingly, "this Echo Cave he mentions will prove to be some new place that the ordinary tourist in the big canyon has never set eyes on?"
"That's my opinion, sir," replied Bob.