July 20th. We left our encampment on the following morning at five, the weather warm and fair. {246} Soon afterwards we passed the mouth of a creek on the south side, which our guide informed us is called by the Spaniards Wharf creek, probably from the circumstance of its washing the base of numerous perpendicular precipices of moderate height, which is said to be the case. It is the stream designated in Pike's map as the Second Fork. A party of hunters in the employ of Choteau, who were taken prisoners by the Spaniards in the month of May, 1817, were conducted up this creek to the mountains, thence across the mountains to Santa Fé.[35] We observed this morning some traces of Indians, but none very recent. On the preceding day we had passed the site of a large encampment, where we saw several horse-pens well fenced. Near the place where we halted to dine, a large herd of elk was seen; but unfortunately they "took the wind of us," and disappeared, giving us no opportunity to fire upon them. Along the river bluffs we saw numerous conic mounds, resembling those of artificial formation so frequently met with near the Ohio and Mississippi rivers, but differing from them by their surface from the apex to the base being terminated by a strait or concave instead of a convex curve, which is usual in those of artificial origin. The natural mounds of which we speak appear usually to contain a nucleus of sandstone, which is sometimes laid bare at the summit or on the sides, and sometimes entirely concealed by the accumulated _débris_ resting upon it, but often contains petrified remains of marine animals. At the end of this day's ride of twenty-six miles, we found the river valley more than a mile in width, and the distant hills or bluffs which bound it low, and of gradual ascent. The boulders, pebbles, and gravel so abundant near the base of the mountain, had been growing gradually less frequent and diminishing in size, till they had now almost entirely disappeared, their place being supplied by a fine {247} sand intermixed with clay, which here composed the surface. The soil is still marked with a character of extreme barrenness, the islands and the immediate margin of the river bearing an inconsiderable growth of cotton-wood and willows, but the great mass of the country being almost destitute of vegetation of any kind. Hunters were sent out immediately on encamping, and returned at dark, bringing a wild cat, an old turkey, and five of her chickens.