Still, he continued his climb, marshaling the forty-seven wethers ahead of him. The going was rough and the sheep were tired and rebellious. But he kept on. At the end of a few minutes he stopped. Or rather, he _was_ stopped. He was stopped by the same form of barrier as had halted the sheep, in the first place, on the other side of the stream, far below. A rock ridge, some twelve feet high, and with a front as precipitous as the wall of a room, loomed in front of him and his flock. It continued to the very edge of the stream and indeed for a yard or two out into the water; the current foaming around its base. There was no way of climbing it. Treve must needs follow, to the right along its base, for an opportunity to skirt it or else to surmount it at some place where the cliff should be lower and less precipitate. So, to the right, he guided his weary captives and moved along the ridge’s base. Presently, the roar of the Chiquita River died away behind them as they pushed forward through the rubble and thickets that fringed the bottom of the cliff. Nowhere did the cliff itself appear to be lower. Instead, it seemed to be sloping upward, gradually, to greater height. The sheep became harder to drive. For hereabouts were wide clearings in the forest and underbrush. These clearings were lush with grass. Here, no flock had grazed; the herdsmen wisely sticking to the other side of the Chiquita. But Treve would not let the wethers loiter. The day was growing late, and the journey to the flock below was momentarily waxing greater. Only once did the collie check his steady drive. That was when the front of the cliff opened wide in a split that had had its origin in some ancient earthquake. Here was an aperture, some six feet wide; the cliff-top meeting above it in a sort of Gothic arch, formed by the toppling of two crest bowlders against each other, long ago. Leaving his fagged-out sheep to browse on the grass, Treve explored this opening. Warily, he advanced into it. For his nostrils registered the scent of wild beasts here. But, as the scent was old and stale, he did not hesitate to continue. Inside the arch was a cave, partly natural, partly caused by the juncture of fallen bowlders at the top. The cavern was about ninety feet wide, by some seventy feet deep; before the gradually shelving roof rock made it too low for the dog’s body to wriggle onward. Its floor was strewn with rock-fragments and with the scattered bones of animals long since slain.