They continued along the bed of the wide canyon. At times they followed the ordinary trail. Then again Frank would express a desire to have a closer look at some high granite wall that hovered, for possibly a thousand feet, above the very river itself; and this meant that they must negotiate a passage for themselves. No doubt John Henry, the guide, must have thought them the queerest pair of tourists he had ever led through the mysteries of the Grand Canyon. But as yet Frank had not thought fit to enlighten him. He was not altogether pleased with the appearance of the guide, and wished to wait until he knew a little more about his ways, before entrusting him with their secret. More than a few times during that day Frank believed he had positive evidence that they were being watched. Of course they met frequent parties of pilgrims wandering this way and that, as they drank in the tremendous glories of the canyon; but occasionally the boy believed he had seen a head thrust out from behind some rock in their rear, and then hastily withdrawn again as he looked. Of course he could make a guess as to who was taking such a interest in the progress of his chum and himself. No one, save Eugene Warringford, would bother for even a minute about what they were doing, since richer quarry by far than a couple of boys would catch the eye of any lawless desperado, like those the two sheriffs were following, bent on making a haul. "Frank," said Bob, when the afternoon was drawing to a close, and they had begun to think of picking out the spot where they would spend the night; "tell me why you chose to head toward the East instead of the other way, where Bright Angel trail attracts so many tourists?" Frank cast one glance toward the guide, as if to make sure that John Henry was far enough in advance not to be able to catch what was said. "I had a reason, Bob," he remarked, seriously. "Before we got down into the canyon, so as to choose which way we would go, I talked with several men who were coming up. And Bob, I learned that an old Moqui Indian had been seen heading toward the East late last night!" "And you think it may have been our friend, Havasupai?" asked Bob. "I'm pretty sure of it, from the descriptions they gave me," came the answer. "But Frank, think how impossible it seems that he could have reached here almost as soon as we did; unless the old warrior was able to fly I don't see how it could be done." "I'm just as much up a tree as you are, Bob," laughed the other; "but, all the same, I believe the Moqui has arrived, and is on his way right now to where Echo Cave lies." "Then he must have an aeroplane to help him out, for I don't see how else he could make it," Bob insisted. "Think for a minute, and you'll see it isn't actually impossible," Frank continued. "He could have made Flagstaff that night, just as we did."