We met here an Indian family on horseback, which had been out to gather service-berries, and were returning loaded. This tree was scattered about on the hills; and the upper part of the pass was timbered with aspen, (_populus trem._;) the common blue flowering-flax occurring among the plants. The approach to the pass was very steep, and the summit about 6,300 feet above the sea--probably only an uncertain approximation, as at the time of observation it was blowing a violent gale of wind from the northwest, with _cumuli_ scattered in masses over the sky, the day otherwise bright and clear. We descended, by a steep slope, into a broad open valley--good soil--from four to five miles wide, coming down immediately upon one of the head-waters of the Pannack river, which here loses itself in swampy ground. The appearance of the country here is not very interesting. On either side is a regular range of mountains of the usual character, with a little timber, tolerably rocky on the right, and higher and more smooth on the left, with still higher peaks looking out above the range. The valley afforded a good level road, but it was late when it brought us to water, and we encamped at dark. The north-west wind had blown up very cold weather, and the artemisia, which was our firewood to-night, did not happen to be very abundant. This plant loves a dry, sandy soil, and cannot grow in the good bottoms where it is rich and moist, but on every little eminence, where water does not rest long, it maintains absolute possession. Elevation above the sea about 5,100 feet.
At night scattered fires glimmered along the mountains, pointing out camps of the Indians; and we contrasted the comparative security in which we traveled through this country with the guarded vigilance we were compelled to exert among the Sioux and other Indians on the eastern side of the Rocky mountains.
At sunset the thermometer was at 50°, and at midnight at 30°.
17th.--The morning sky was calm and clear, the temperature at daylight being 25°, and at sunrise 20°. There is throughout this country a remarkable difference between the morning and mid-day temperatures, which at this season was very generally 40° or 50°, and occasionally greater; and frequently, after a very frosty morning, the heat in a few hours would render the thinnest clothing agreeable. About noon we reached the main fork. The Pannack river was before us, the valley being here 11/2 miles wide, fertile, and bordered by smooth hills, not over 500 feet high, partly covered with cedar; a high ridge, in which there is a prominent peak, rising behind those on the left. We continued to descend this stream, and found on it at night a warm and comfortable camp. Flax occurred so frequently during the day as to be almost a characteristic, and the soil appeared excellent. The evening was gusty, with a temperature at sunset of 59°. I obtained, about midnight, an observation of an emersion of the first satellite, the night being calm and very clear, the stars remarkably bright, and the thermometer at 30°. Longitude, from mean of satellite and chronometer, 112° 29' 52", and latitude, by observation, 42° 44' 40".
