At length the track, which had led them steadily over rising ground almost from the moment of starting, conducted the party to the entrance of a very wild, romantic, and picturesque-looking gorge which seemed to pierce right into the very heart of the mountains. For some time the going had been growing increasingly difficult, especially for the two horsemen; and now a single glance ahead sufficed to show that it must speedily become impossible for mounted men, for the side of the mountain grew increasingly steep, as one looked forward, until, about a quarter of a mile farther on, it seemed to be practically perpendicular, while the pine trees grew so thickly that in places it appeared as though there would be scarcely room for a man, much less a horse, to pass; moreover, the side of the hill was covered with big outcrops of rock, interspersed with loose boulders, to pass over and among which would require a clear head, a steady eye, and a sure foot. The two young men therefore determined to dismount forthwith and proceed on foot, leaving their horses in charge of one of the negroes. And it was well that they did so, for the path almost immediately grew so steep and difficult that before they had advanced another hundred yards the party found it necessary to frequently drop on their hands and knees to pass some of the more awkward places without being precipitated into the stream which they heard brawling some hundreds of feet below them at the bottom of the ravine. And now, as they slowly and with difficulty made their way along the steep mountain-side, a low murmur, gradually growing in strength and volume of sound, told them that they were approaching a waterfall or cataract of some sort: and after another half-hour of exhausting and perilous crawling, and slipping, and sliding over the loose and shaley ground, they came in sight of it as it opened out before them from behind an enormous, precipitous crag--a solid column of water about twenty feet in diameter, leaping out of a narrow cleft in the rock some three hundred feet above them, and gradually resolving itself into mist as it plunged down into the dark and gloomy depths of the gorge below. To Carlos--and still more to Jack--it seemed impossible that the fugitive should have chosen to pursue the track which they were now following--for to where did it lead? The place was quite new to Carlos; he had never been there before, and it seemed unlikely in the extreme that a stranger to the neighbourhood as Alvaros was would know more about it than one who had dwelt only a few miles off during practically his whole life: yet Juan was now pressing on, a long way ahead, as though he were following on a hot scent, and presently he disappeared altogether in a thick cluster of fir trees high up the side of the hill. Ten minutes later he emerged on the other side of the clump and went scrambling toward the spot where the stream of water spouted out of the rock.