A long tramp was before them. The arrangements preparatory were, therefore, made with corresponding care and diligence. The route led up the Arkansas River to the point where that stream leaves the mountains; thence they made a circuit by the Ballo Salado, or Soda Springs, coming back again upon the Arkansas, striking the stream above its great canon. Thence they journeyed on to the head waters of the river. Here they left the Arkansas River and took a direct route for the Piney River, down which latter stream they traveled to a spot within twenty-five miles of its mouth. From this place they continued their explorations of the country to the head of White River. Following down it, they soon reached the mountains. Crossing them, they proceeded to Prevost's Fork. At this spot a desperate fight once occurred between a party of trappers and a band of hostile Indians. The trappers were commanded by a man whose name has ever since been applied to the stream. Prevost, although he had a strong party and fought a most desperate battle, nevertheless was outnumbered, outgeneralled, and most completely overpowered. The Indians succeeded in killing the entire party, including himself, with but four exceptions. These four escaped only with the greatest difficulty and prudence. Through them the particulars of the affair became known to the mountaineers. Col. Fremont (we should before this have mentioned that Fremont had been promoted in the corps of Topographical Engineers from the post of Lieutenant to the rank of Captain by brevet) now examined the country as far as the south side of the Great Salt Lake, passing on his route a smaller body of water, which, for many years, has been known as Little Utah Lake. The command halted at Great Salt Lake a few days to recruit, preparatory to undertaking the further exploration of the lake, together with one of its largest islands, which would be reached by this southern route. The Indians met with on the journey, informed them that on this island there was plenty of fresh water, and game in abundance. On arriving at a suitable place, Col. Fremont pitched his tents for the main camp. On the following morning, taking Kit Carson and a few chosen men, Col. Fremont started to explore the island. The reports of the Indians were proven to be true. In addition to plenty of fresh water and game, they discovered very good timber growing there. The game, which proved to be antelope, was so abundant that they decided to kill from the herds a quantity sufficient for future use. The island was about fifteen miles in length by about five in breadth. From the main land to the island they were able to ride their horses, as the water was not deep. Upon the banks of the lake they found the salt deposit to vary from the thickness of a wafer to the depth of twelve inches.