Glancing your eye along the map, you will see a small stream entering _Utah lake_, south of the Spanish fork, and the first waters of that lake which our road of 1844 crosses in coming up from the southward. When I was on this stream with Mr. Walker in that year, he informed me that on the upper part of the river are immense beds of rock-salt of very great thickness, which he had frequently visited. Farther to the southward, the rivers which are affluent to the Colorado, such as the Rio Virgen, and Gila river, near their mouths, are impregnated with salt by the cliffs of rock-salt between which they pass. These mines occur in the same ridge in which, about 120 miles to the northward, and subsequently in their more immediate neighborhood, we discovered the fossils belonging to the oolitic period, and they are probably connected with that formation, and are the deposite from which the Great Lake obtains its salt. Had we remained longer, we should have found them in its bed, and in the mountains around its shores. By observation the latitude of this camp is 41° 15' 50", and longitude 112° 06" 43".
The observations made during our stay give for the rate of the chronometer 31.72", corresponding almost exactly with the rate obtained at St. Vrain's fort. Barometrical observations were made almost hourly during the day. This morning we breakfasted on yampah, and had only kamas for supper; but a cup of good coffee still distinguished us from our _Digger_ acquaintances.
12th.--The morning was clear and calm, with a temperature at sunrise of 32°. We resumed our journey late in the day, returning by nearly the same route which we had traveled in coming to the lake; and, avoiding the passage of Hawthorn creek, struck the hills a little below the hot salt-springs. The flat plain we had here passed over consisted alternately of tolerably good sandy soil and of saline plats. We encamped early on Clear creek, at the foot of the high ridge; one of the peaks of which we ascertained by measurement to be 4,210 feet above the lake, or about 8,400 feet above the sea. Behind these front peaks the ridge rises towards the Bear River mountains, which are probably as high as the Wind River chain. This creek is here unusually well timbered with a variety of trees. Among them were birch, (_betula_,) the narrow-leaved poplar, (_populus angustifolia_,) several kinds of willow, (_solix_,) hawthorn, (_cratægus_,) alder, (_alnus viridis_,) and _cerasus_, with an oak allied to _quercus alba_, but very distinct from that or any other species in the United States.