"Clark got more and more discouraging news about getting down the Lemhi River, on which they were camped, and the big river below--the Salmon River. But with the old man for guide, he went about seventy miles, into the gorge of the Salmon River, before he would quit. But he found that no man could get down that torrent, with either boat or pack train. He gave it up. They were nearly starved when they got back at the Indian camp, where Lewis and the other men were trading. Sacagawea had kept all her people from going on east to the buffalo country, though now they none of them had anything to eat but a few berries and choke cherries. If the Indians had left, or if they had been missed by the party, the expedition would have ended there. The Indian girl once more had saved the Northwest for America, very likely. "Now the old Indian guide said he knew a way across, away to the north. They hired him as guide. They traded for twenty-nine horses, and at last packed them and set out for the hardest part of their journey and the riskiest, though they did not know that then. On August 30th they set out. At the same time Cameahwait and his band set off east, after their fall hunt. "That was the last that Sacagawea ever saw of her brother or her girl friend. She went on with her white husband, into strange tribes--nothing further for her to look forward to now, for she was leaving home for another thousand miles, in the opposite direction. "And that ended the long, hard, risky time the company of Volunteers for Discovery of the Northwest had in crossing the Continental Divide. We lie at the foot of their pass. Yonder they headed out for the setting sun!" "Let's go on after them, Uncle Dick!" exclaimed Jesse. "We've got a good outfit, and we're not afraid!" "I've been expecting that," rejoined their leader. "I was afraid you'd want to go through! But we can't do it, fellows, not this year at least. There's the school term we've got to think of. We're nearly three thousand miles from St. Louis. That means we'll have to choose between two or three weeks of the hardest kind of mountain work and back out when we've got nowhere, and taking a fast and simple trip to the true head of the Missouri. Which would you rather do?" "We don't like to turn back," said Rob. "Well, it wouldn't be turning back, really. It would be going to the real head of the Missouri--and neither Lewis nor Clark ever did that, or very many other men." Billy spoke quietly.