The explorers took up their quarters for the winter amongst the Mandans, on the 1st of November. They built huts, as comfortable as possible with the materials at their command; and in spite of the extreme cold, gave themselves up to the pleasures of hunting, which soon became a positive necessity of their existence. When the ice should break up on the Missouri, the explorers hoped to continue their voyage; but on their sending the boat down to St. Louis, laden with the skins and furs already obtained, only thirty men were found willing to carry the expedition through to the end. The travellers soon passed the mouth of the Yellowstone River, with a current nearly as strong as that of the Missouri, flowing through districts abounding in game. Cruel was their perplexity when they arrived at a fork where the Missouri divided into two rivers of nearly equal volume, for which was the main stream? Captain Lewis with a party of scouts ascended the southern branch, and soon came in sight of the Rocky Mountains, completely covered with snow. Guided to the spot by a terrific uproar, he beheld the Missouri fling itself in one broad sheet of water over a rocky precipice, beyond which it formed a broken series of rapids, extending for several miles. [Illustration: "He beheld the Missouri."] The detachment now followed this branch, which led them into the heart of the mountains, and for three or four miles dashed along between two perpendicular walls of rock, finally dividing itself into three parts, to which were given the names of Jefferson, Madison, and Galatin, after celebrated American statesmen. The last heights were soon crossed, and then the expedition descended the slopes overlooking the Pacific. The Americans had brought with them a Soshone woman, who had been protected as a girl by the Indians of the east, and not only did she serve the explorers faithfully as an interpreter, but also, through her recognition of a brother in the chief of a tribe disposed to be hostile, she from that moment secured cordial treatment for the white men. Unfortunately the country was poor, the people living entirely on wild berries, bark, and the little game they were able to obtain. The Americans, little accustomed to this frugal fare, had to eke it out by eating their horses, which had grown very thin, and buying all the dogs the natives would consent to sell. Hence they obtained the nickname of Dog-eaters. As the temperature became milder, so did the character of the natives, whilst food grew more abundant; and as they came down the Oregon, also known as the Columbia, the salmon formed a seasonable addition to the bill of fare. When the Columbia, which is dangerous for navigation, approaches the sea, it forms a vast estuary, where the waves from the offing meet the current of the river. The Americans more than once incurred considerable risk of being swallowed up, with their frail canoe, before they reached the shores of the ocean.