"We must part, Will," said Meriwether Lewis. "It is our duty to learn all we can of this wonderful country. I will take the Indian trail straight across. Do you go on down the way we came. Pick up our caches above the three forks of the Missouri, and then cross over the mountains to the Yellowstone. Make boats there, and come on down to the mouth of that river. You should precede me there, perhaps, by some days. Wait then until I come."
With little more ado these self-reliant men parted in the middle of the vast mountain wilderness. They planned a later junction of their two parties at the mouth of a river which then was less known than the Columbia had been, through a pass which none of them had ever seen.
Lewis had with him nine men, among them Sergeant Gass, the two Fields boys, Drouillard and Cruzatte, the voyageurs. Sacajawea, in spite of her protest, remained with the Clark party, where her wonderful knowledge of the country again proved invaluable. This band advanced directly to the southward by easy and pleasant daily stages.
"That way short path over mountains," said Sacajawea at length, at one point of their journey.
She pointed out the Big Hole Trail and what was later known as Clark's Pass over the Continental Divide. They came to a new country, a beautiful valley where the grass was good; but Sacajawea still pointed onward.
"That way," said she, "find boat, find cache!"
She showed them another gap in the hills, as yet unknown; and so led them out by a short cut directly to the caches on the Jefferson!
But they could not tarry long. Boots and saddles again, pole and paddle also, for now some of the men must take to the boats while others brought on the horses. At the Three Forks rendezvous they made yet other changes, for here the boats must be left. Captain Clark must cross the mountain range to the eastward to find the Yellowstone, of which the Indian girl had told him. Yonder, she said, not quite a full day's march through a notch in the lofty mountains, they would come to the river, which ran off to the east.
Not one of them had ever heard of that gap in the hills; there was no one to guide them through it except the Indian girl, whose memory had hitherto been so positive and so trustworthy. They trusted her implicitly.
"That way!" she said.
Always she pointed on ahead confidently; and always she was right. She was laying out the course of a railroad which one day should come up the Yellowstone and cross here to the Missouri.