"Yes, we'll go back," rejoined the old miner. "But go slow, or you may make matters wuss. I kin follow a clear trail, even of three hosses, but I can't follow a trail mixed up backward an' forward." They rode back slowly until at least half a mile had been covered. Then they shouted, but only a dismal echo came back. Dick fancied once that he heard Tom calling, but was not sure. Daylight found them still searching around, Dick and Sam with more sober faces than they had worn in many a day. They knew only too well the danger of becoming lost in those wild mountains. "Perhaps he has fallen in with Baxter's party," suggested Dick, as they came to a halt at the edge of a cliff overlooking a rushing river far below. It was past the breakfast hour, yet none of them felt like eating. "Be careful how you expose yourself," observed Jack Wumble, as he screened himself and his horse behind some brush. "It won't do no good to Tom to let your enemies see you." "If only we hadn't lost the trail," sighed Sam. The back trail had disappeared, on some rocks half an hour before and all efforts to take it up again had proved unsuccessful. The Rover boys felt very much disheartened. Without Tom what was the use of going ahead to locate the missing mine? "He's worth a dozen mines," said Dick. "We must find him--we simply must." But they were "stumped," to use Sam's way of expressing it, and with nothing better to do, Jack Wumble drew further back into the bushes, tethered his horse and got out the provisions for a meal. The boys ate mechanically and were soon done. Then Wumble got out his pipe and began to smoke more vigorously than ever. "If we had a field glass we might spot him," he observed. "He can't be such a terrible distance away." "I'm going to fire my pistol again," said Dick, and did, so, but no response came back and he re-loaded as crestfallen as ever. It was a clear day, but the very sun seemed a mockery as it beamed down upon them. "Supposing we separate and renew the hunt?" suggested Sam, but Wumble slowly shook his head. "None o' that, lad. It will only be a case of another one lost. No, we must keep within sight of each other, no matter what we do. Come, I have an idea of looking into the valley on the other side of this hill, and then we can try the hill yonder." Anything was better than sitting still, and once more they rode on. For the time being the enemy was almost forgotten. They were going down along the edge of the cliff when, without warning, Dick's horse began to slip, having stepped on a rock which was insecure. "Hi! whoa!" yelled the youth, and tried to hold the horse back. Then, as he saw the animal could not save himself, he leaped for the ground. The horse managed to scramble to a place of safety, but Dick, in trying to avoid a dangerous hoof stroke from the beast, lost his balance and went crashing down into the bushes overhanging the cliff!