Tad, looking out across the river while the others worked, saw what he took at first for a log drifting down rapidly along the Mississippi side. It was not until he caught the flash of a paddle that he realized it was not a log but a dugout canoe. Once, when the little craft was silhouetted for a moment against a lighter background, he made out a single dark figure paddling strongly in the stern. The next instant the canoe vanished past the end of an island. If Tad had not been nervously keyed up by what he had been through, it is probable he would hardly have noticed the occurrence. Canoes were not very common along the lower river, but he had seen them occasionally, manned by Indians or white trappers, coming down from the smaller streams. It was not the craft itself but something swift and furtive in the motions of the paddler that gave the boy an odd feeling of uneasiness. However, he did not even mention the canoe to Abe and Allen, for he was a little ashamed of his vague fears. When the oar was finished they pushed on for another hour or two, and Abe was in favor of making up the time they had lost by traveling part of the night. But the sky, which had been clear most of the afternoon, had started to cloud up at sunset and was now heavily overcast. “She’ll be black as yer hat in another hour,” Allen counseled. “With no moon to help, ye’ll never be able to steer betwixt all these islands.” “All right,” Abe agreed grudgingly. “But we’ll have to make it watch an’ watch ag’in tonight, if we tie up here.” Though Allen could see little sense in this precaution, he finally consented, provided he could take the first turn, and they made their mooring for the night. Tad offered to stand one guard, but the others would not hear of it. Probably he would have made a poor watchman, for as it turned out he slept again like a log from dark to daylight. “What d’ye say _now_?” Allen called cheerfully from the breakfast fire next morning. “Not a sound all night. We jest wasted four hours o’ sleep apiece.” But Abe, who had gone ashore for more wood, did not reply. He was stooping over something on the ground, examining it intently. “Come here a minute,” he said, finally, and both the others went to join him, sensing a discovery of some kind. His face wore a curious expression when he looked up. “If I was a real crackajack at this sort o’ thing,” he said, “I’d tell ye jest when this yere was made, an’ by what. The way things are, I kin only guess.” He was kneeling before a little bare patch of black earth. At first Tad thought there was nothing there. Then he got down beside Abe, and when he peered closely he saw, very faint across the firm surface, the print of a naked foot. Allen whistled softly. “Big b’ar, ain’t it?” he asked. “Look again,” said Abe, laconically.