"Yes," remarked Uncle Dick, "that's what we call adjusting to an environment. I will say these Mandans were rather efficient on the whole, and not bad engineers and architects." They did not tarry long, although they made their second encampment within the lines of the old Fort Berthold Reservation, for they found all the Indians wearing white men's clothing, and using wagons and farm implements, and Jesse said they had more Indianish Indians in Alaska. Now they bore rather sharply to the north, feeling for the line of the railway, which they struck at a village about midway between the Little Knife and the White Earth Rivers. The early afternoon of their fourth day brought them back once more to the sight of the Missouri, at the town of Buford, near the Montana line and opposite the mouth of the Yellowstone. Following their usual custom, they made camp outside the vicinity of the town, after purchasing the supplies they needed for the day and for the return trip of their obliging friend from Mandan, who now reluctantly decided that he could accompany them no farther. "I'd rather go on with you than do anything I know," said he, "but it's going to be quite a trip, and I won't have time, even if we could get through with a car." Uncle Dick nodded. "Really the best way to do this would be to take ship again here and follow the river up the Great Falls," he said; "but by the time we got a boat rigged and had made the run up--best part of six hundred miles--we'd be almost a month further into the summer--because the river is swifter above here. They made good time, but it was mostly cordelle work. And, using gas motors, the boys wouldn't have much chance of any real sport and exercise, which, of course, I want them to have every summer when possible. "Get your map, John--the big government map--and let's have a look at this country in west of here." John complied. They all bent over the map, which they spread down on the floor of the tent. Their gasoline camp lantern shed its brilliant light over them all as they bent down in study of the map. "You'll see now that we're almost at the farthest north point on the Missouri River. From here it runs almost west to the Great Falls, and then almost south. Now our new railroad (the Great Northern Railroad) will take us to the Great Falls of the Missouri, but it by no means follows the Missouri. On the contrary, a little over two hundred miles from here, I'd guess, it strikes the Milk River--as Lewis and Clark called it--and follows that river half across the state of Montana. It would carry us out to the Blackfeet Reservation, and what is now Glacier Park--my own hunting ground among the Blackfeet, where I knew Joe Kipp--but that is entirely off the map for us."