Captain Abbey was at the head of his men, and several hundred feet in advance of any other body of cavalry, when, without warning, thirty-two of the Riverlawns were caught on a mountain trail not over six feet broad, having on one side a wall or cliff nearly a hundred feet high, and on the other a sheer descent of twice that number of feet into a hollow filled with jagged rocks. The accident which brought this condition of affairs about was in reality as simple as it was serious. The trail wound around the mountain in the shape of a horseshoe, and the cavalrymen were journeying slowly along at the bottom of the curve, when some rocks and sand far above them began to slide down. The rumble was heard in time to allow the riders to escape the landslide, but immediately the trail before and behind them was choked up with boulders and sand to the height, or depth, of fifteen feet or more. It cannot be denied that the members of the first company who were thus caught were greatly alarmed. Second Lieutenant Burton was with Captain Abbey, and he yelled out that the mountain was coming down. For several minutes a score of cries and yells filled the air, but gradually these died away, and when the landslide stopped, and the dust had rolled away, the cavalrymen looked about them to see what damage had been done. "Nobody hurt," announced Captain Abbey. "That was the most fortunate landslide I ever saw." "We'll have to go back," said Lieutenant Burton, who had surveyed the disaster ahead. "We can't climb over that mass of rocks,--it wouldn't be safe." "I'd like to know how we are going back," put in one of the sergeants. "We are blocked in the rear as well as in front. That stuff came from the top of yonder ridge, and half of it slid down on this side of the curve and half on the other. We are hemmed in." This announcement made all feel very uneasy, and more than one cavalryman turned slightly pale. If they couldn't advance or retreat what were they to do? "Let us make a careful investigation of our condition first," said Captain Abbey, who was as calm as anybody in the detachment. "If we can do nothing better, we can clear that rubbish off the trail." At this Lieutenant Burton shook his head. "That would be a dangerous undertaking, Captain. When rocks and sand once begin to slide there is no telling when they will stop." "But this stuff can only slide into the valley below, Burton." "This stuff can, that's true; but it may bring down ten times as much on our heads." At this Captain Abbey shrugged his shoulders. "Well, we'll investigate first and lay plans afterward. We can't stay here forever. In a couple of hours more it will be dark."