July 7.--They reached Wisdom River, and stopped for dinner at a hot spring situated in the open plain. The bed of the spring is about fifteen yards in circumference, and composed of loose, hard, gritty stones, through which the water boils in large quantities. It is slightly impregnated with sulphur, and so hot, that a piece of meat, about the size of three fingers, was completely cooked in twenty-five minutes. July 8.--They arrived at Jefferson's River, where they had deposited their goods in the month of August the year before. They found every thing safe, though some of the goods were a little damp, and one of the canoes had a hole in it. They had now crossed from Traveller's-Rest Creek to the head of Jefferson's River, which seems to form the best and shortest route over the mountains during almost the whole distance of one hundred and sixty-four miles. It is, in fact, an excellent road; and, by cutting down a few trees, it might be rendered a good route for wagons, with the exception of about four miles over one of the mountains, which would require a little levelling. July 10.--The boats were now loaded, and Capt. Clarke divided his men into two bands. Sergt. Ordway, with nine men, in six canoes, was to descend the river; while Capt. Clarke, with the remaining ten, the wife and child of Chaboneau, and fifty horses, were to proceed by land to the Yellowstone. The latter party set out at five in the afternoon from the forks of the Missouri, in a direction nearly east. The plain was intersected by several great roads leading to a gap in the mountain about twenty miles distant, in a direction east-north-east; but the Indian woman, who was acquainted with the country, recommended another gap more to the south, through which Capt. Clarke determined to proceed. They started early the next morning, and, pursuing the route recommended by the squaw, encamped in the evening at the entrance of the gap mentioned by her. Through this gap they passed next day, and, at the distance of six miles, reached the top of the dividing ridge which separates the waters of the Missouri from those of the Yellowstone. Nine miles from the summit, they reached the Yellowstone itself, about a mile and a half below where it issues from the Rocky Mountains. The distance from the head of the Missouri to this place is forty-eight miles, the greater part of which is through a level plain. They halted for three hours to rest their horses, and then pursued the Buffalo Road along the banks of the river.