The locality where these objects are found has considerable historic interest. The ford just below the Mud Volcano was long used by the hunters and trappers who passed up and down the river. Folsom crossed it in 1869, and the Washburn party in 1870. The Nez Percés encamped here two days, in 1877, and here transpired a part of the episode elsewhere related. Hither came General Howard, in pursuit of the Indians, although he did not cross the river at this point. _Trout Creek_ (9.5 miles) has a most peculiar feature, where the tourist route crosses it, in the form of an extraordinary doubling of the channel upon itself. It was this stream which Mr. Hedges, in 1870, called "a lazy creek coiled up like a monster serpent under a sand bluff." _Sulphur Mountain_ (11.5 miles) is half a mile back from the main route. At its base is a remarkable _Sulphur Spring_, always in a state of violent ebullition, although discharging only a small amount of water. This is highly impregnated with sulphur, and leaves a yellow border along the rivulet which carries it away. The best time to visit Sulphur Mountain is on a clear sharp morning. The myriad little steam vents which cover the surface of the hill are then very noticeable. _Hayden Valley_ is a broad grassy expanse extending several miles along the river and far back from it on the west side. It was once a vast arm of the lake. It comprises some fifty square miles, and is an important winter range for the Park buffalo and elk. [Illustration: _Terry Engr. Co._ _Gandy._ Rapids Above Falls.] [Illustration: _Terry Engr. Co._ _U. S. Geological Survey of the Territories._ Upper Fall of the Yellowstone. Distant view.] The river along the lower portion of this valley is the most tranquil and lovely stream imaginable--broad, deep, transparent, flowing peacefully around its graceful curves, disturbed only by the splashing trout which inhabit it. There is little here to suggest the mad turmoil into which it is soon to plunge. At a point fifteen miles below the lake, the river and road are forced by the narrowing valley close together. The stream becomes suddenly broken into turbulent cascades as it dashes violently between precipitous banks and among massive boulders. The road also becomes decidedly picturesque. Hung up on the almost vertical cliff overlooking the rapids, it forms a short drive unsurpassed for interest anywhere else in the Park. At one point it crosses a deep ravine over the highest bridge on the road system. Just to the left of this bridge, in the bottom of the ravine, still stands the tree upon which some white man carved his initials away back in 1819.