This Indian remained with them until the crack was reached, where he resumed his pack and went on. The opening was an irregular one, from four to eight feet wide and of unfathomable depth. Fortunately the sides were well defined and firm, so they had small trouble in leaping across. "It was good of them to send a man back," said the doctor, as he paused to peer down into the crevasse. "Had we not been warned we might have slipped into that without knowing it." The trail now wound in and out among a number of small hills, and once again the party ahead was lost to sight. With the increasing cold came a stiff wind through the passes, bringing down upon their heads a veritable storm of snow, swept from the mountain tops above. "I can readily understand how impossible it would be to make one's way through this Pass during the winter," said Dr. Barwaithe. "A regular fall of snow would mean a blizzard down here and a snowing in from which there would be no escape until spring arrived." "And think of the cold!" said Earl. "Phew! the thermometer must go to about forty below zero!" "It does go as low as that at times," replied his uncle. "No; travelling through this Pass during the long Alaskan winter is entirely out of the question. The man to undertake it would be a madman." They had come to the end of the comparatively level portion of the trail, and now climbing so dangerous was at hand that little more was said. From one steep icy elevation they would crawl to the next, until several hundred feet up. Then came a turn around a cliff where the passageway was scarcely two feet wide, with a wall on one side and what appeared misty, bottomless space on the other. Here the Indians had fastened a hand-rope which each was glad enough to clutch as he wormed his way along to safer ground. "Well, I don't want any more of that!" said Earl, with a long sigh of relief. "A slip there, and it would be good-by, sure!" "Yes, and I guess they would never even get your body," added Randy. There was no time left to halt, for the Indians were pressing on, their endurance, and especially the endurance of the women and the boys, proving a constant wonder to Randy and Earl, the latter declaring that they must be tougher than pine knots to stand it. "One more big climb, boys, and we'll be at the summit!" was the welcome announcement made by Captain Zoss; but when Earl and Randy looked at the climb he mentioned their hearts fairly sank within them and they wondered how in the world they were going to make it without its costing them their lives. An almost sheer wall of ice and snow confronted them, rising in an irregular form to a height of four hundred feet. This cliff, if such it might be called, was more light at its top than at the base, and consequently it appeared to stand out towards them as they gazed up at it. Along the face the Indian pack-carriers were crawling, like flies on a lumpy whitewashed wall.