"It's a small black bear," flashed into his mind. Instantly he ran with all speed to the cabin for the shot-gun, which he kept loaded with buckshot. The captain's party had carried off the only rifle, and David was now sorry he had not brought his own. He caught up the shot-gun, however, and slipping a few extra cartridges into his pocket, ran back to the bluff where Shep stood guard. The strange animal had disappeared. For a moment David was disconcerted. He had not thought the bear could get away so quickly, nor could he be sure whether it had gone into the fringe of trees and bushes along the river-bank or continued up the slope. He hesitated, too, before setting out to attack such an animal with only a shot-gun for a weapon and a dog of doubtful courage as an ally. The next instant, however, he had decided to track and kill the beast if possible, and calling Shep to follow, he hurried down to the river's sandy brink to examine the tracks by the waning light. He was quite puzzled at finding that they were almost identical in appearance with those made by Shep, but at length the truth dawned upon him. He had to deal, not with a young bear, but with a full-grown wolf! He now endeavored to make Shep take the scent, but Shep was not trained to such work and sniffed around indiscriminately without attempting to follow the animal's trail. There was nothing for it but to track the wolf himself. He accordingly traced every track as far as it would lead him. One proceeded from the fringe of bushes to the point where the animal drank, while another led straight up the face of the bluff. The latter he followed as far as the sand continued; but the top of the elevation was grassy, and in the growing darkness the trail was quickly lost. Keeping his eyes and ears alert for the slightest sound, David penetrated some distance into the open woods, but without discovering further signs of the animal. Satisfied that nothing more could be done, he returned to camp, and took unusual pains to fasten the frail cabin door securely when he turned in for the night. Nor was he destined to sleep without an alarm. A noise of rattling tin awoke him with a start. The interior of the cabin was quite dark, since, as we have said, there were no windows; but the nights were not yet without some light, and feeble rays outlined every chink as David sat up, threw off his mosquito net, and looked around. Again came the rattle of tin. It evidently proceeded from a pile of empty cans just outside the cabin. He brought himself to a kneeling posture and pressed his face close to one of the widest chinks. Presently he distinguished an animal nosing among the cans and making the noise which had awakened him. It was Shep. David spoke to the dog, and having seen him walk away with a somewhat shame-faced air, he settled himself once more among the blankets and was soon asleep again.