The valley grew wilder and more rugged as they proceeded. In places, its bottom was filled with muskegs, cumbered with half-submerged, decaying trunks of fallen trees; and when they could not spring from one falling log to another they sank in slime and water to the knee. They entered transverse valleys, and after hours of exhausting labour, abandoned the search of each in turn and plodded back to the one they had been following. Their boots and clothing suffered; their packs were rent upon their backs, and, since men engaged in such work must be generously fed, their provisions diminished rapidly. At length, one lowering afternoon, they were brought to a standstill by the river, which forked into two branches, one of which came foaming out on a cleft in the rocks. This would have mattered less had it flowed across the level; but just there it had scored itself out a deep hollow, from which the roar of its turmoil rose in long reverberations. Carroll, who was aching all over, stood upon the brink, and first of all gazed ahead. He surmised from the steady ascent and the contours of the hills that the valley was dying out, and that they should reach the head of it in another day's journey. The higher summits, however, were veiled in leaden mist, and there was a sting in the cold breeze that blew down the hollow and set the ragged firs wailing. Then he glanced dubiously at the dim, green water, which swirled in deep eddies and boiled in white confusion among the fangs of rock sixty or seventy feet below. Not far away the stream was wider and he supposed in consequence shallower, though it ran furiously. "It doesn't look encouraging, and we have no more food left than will take us back to the sloop if we're economical," he said. "Do you think it's worth while going on?" "I haven't a doubt about it," Vane declared. "We ought to reach the head of the valley and get back here in two or three days." "Three days will make a big hole in the provisions." "Then we'll have to put up with short rations," Vane rejoined. "If you're determined, we may as well get on." He stepped cautiously over the edge of the descent, and went down a few yards with a run, while loosened soil and stones slipped away under him. Then he clutched a slender tree, and proceeded as far as the next on his hands and knees. After that, it was necessary to swing himself over a ledge, and he was on the whole astonished when he alighted safely on one below, from which he could scramble down to the narrow strip of gravel between rock and water. He was standing, breathless, looking at the latter, when Vane joined him. The stones dipped sharply, and two or three large boulders, ringed about with froth, rose near the middle of the stream, which seemed to be running slacker on the other side of them. There was nothing to show how deep it was, but Carroll braced himself for an effort and sturdily plunged in.