Westbound, the trip up Lolo Creek began one of the expedition's most arduous and life-threatening stretches, while eastbound the passage down Lolo Creek marked victory over one of the most formidable barriers to cross-country travel they encountered. When Meriwether Lewis reached the Continental Divide south of the Bitterroot Valley on August 12, 1805, his expectation of a plain descending toward the Pacific Ocean collapsed when he saw immense ranges of high mountains still to the west. The captains enlisted a Shoshone guide they called Old Toby, who told them of a rugged Indian road through the mountains leading west, and after stopping for a few days at Traveler's Rest to prepare, the expedition left on September 11, 1805, following a trail along ridges above the brush-choked creek bottom. By September 22, 1805, after what Clark called a very bad road over hills and through steep hollows, with horses injured in falls, snow nearly obliterating the trail, and the party suffering from diarrhea, skin rashes, lethargy, and other symptoms of malnutrition, they emerged from the mountains into the home of the Nez Perce, who generously assisted their journey west. After wintering at Fort Clatsop near the Oregon Coast, the expedition returned east across the Bitterroots and reached Traveler's Rest on June 30, 1806. The captains then divided the party to explore more of the Louisiana Territory on the way home: leaving Traveler's Rest on July 3, 1806, Lewis led nine mounted soldiers, seventeen horses, and his Newfoundland dog, Seaman, north to the Clark Fork and up the Bitterroot River, while Clark led the rest of the party south down the Bitterroot Valley, with plans to reunite in a month at the confluence of the Yellowstone and Missouri rivers.