From there the route taken branched off along Indian Creek, which could only be called a mode of passage by courtesy. They could not travel along the banks for timber, and rock came to the water's edge, and as the creek bed was a succession of boulders and rapids, half the time the sleds had to be lifted and practically carried over obstructions, in order that perhaps for twenty or thirty feet there might be a spot of good going. Three days it took them to cover the twelve miles, and April 13th found the party at the entrance of the Chulitna Pass, 3,000 feet above sea level. Here, of course, it was practically blind going, but despite the hard trip the dogs were in fairly good condition and with Bulson's muscle and Harry's knowledge of the multifold peculiarities of the "husky," they managed to worry through the pass in four days, reaching the little cache and log hut at the mouth of the Jack River, which was their objective point. So far they had been able to go with dogs, and no further, whereupon the work of unpacking the sleds was begun, the two canoes duly inspected and found uninjured, the supplies redistributed, and the two Indians who had been picked up at Sushitna Station to take back the dogs, were promptly sent back upon the downward trail before the river should break up and make dog-travel impossible. Of course, as it was pointed out, rapid time could be made with an empty sled, and the drivers need rarely walk. During all this time the whole energies of the party had been given entirely to making headway, and no time had been spent either in topographical or geological work, but the urgency had borne fruit. Rivers told Roger that he had allowed two months and a half for the journey to their present place, and they were ten days ahead of the schedule. "And what is to be done now, Mr. Rivers?" asked the boy. "Wait till the ice breaks, Doughty," replied the geologist, "and in the meantime some little investigation of the range may not be amiss." The third day after they had made their semi-permanent camp Rivers took the boy with him on a geological trip back to Caribou Pass, the most practicable opening in the entire Alaskan Range. He spent some time in explaining to the boy the general configuration of the range, and taught him a good deal about the glacial conditions of the region. Happening to observe a curious immense boulder in the pass, in the form of a rock almost flat on the top, about twenty feet square and nearly as many high, it occurred to Rivers that he might discern distinct striated lines of glaciation if he could get up there on the rock to see. The boulder was somewhat difficult to climb, but by getting on Roger's shoulders, the geologist was able to reach a point where he could get a grip of the rock.