The trail to Oregon, followed by traders and emigrants, crosses the Rocky Mountains at a point known as the South Pass, where a break in the chain occurs of such moderate and gradual elevation as to permit the passage of waggons with tolerable facility. The Sweet Water Valley runs nearly to the point where the dividing ridge of the Pacific and Atlantic waters throws off its streams to their respective oceans. At one end of this valley, and situated on the right bank of the Sweet Water, a huge isolated mass of granitic rock rises to the height of three hundred feet, abruptly from the plain. On the smooth and scarped surface presented by one of its sides, are rudely carved the names and initials of traders, trappers, travellers and emigrants, who have here recorded the memorial of their sojourn in the remote wilderness of the Far West. The face of the rock is covered with names familiar to the mountaineers as those of the most renowned of their hardy brotherhood; while others again occur, better known to the science and literature of the Old World than to the unlearned trappers of the Rocky Mountains. The huge mass is a well-known landmark to the Indians and mountaineers; and travellers and emigrants hail it as the half-way beacon between the frontiers of the United States and the still distant goal of their long and perilous journey. It was a hot sultry day in July. Not a breath of air relieved the intense and oppressive heat of the atmosphere, unusual here where pleasant summer breezes, and sometimes stronger gales, blow over the elevated plains with the regularity of trade-winds. The sun, at its meridian height, struck the dry sandy plain and parched the drooping buffalo-grass on its surface, and its rays, refracted and reverberating from the heated ground, distorted every object seen through its lurid medium. Straggling antelope, leisurely crossing the adjoining prairie, appeared to be gracefully moving in mid-air; whilst a scattered band of buffalo bulls loomed huge and indistinct in the vapoury distance. In the timbered valley of the river deer and elk were standing motionless in the water, under the shade of the overhanging cottonwoods, seeking a respite from the persevering attacks of swarms of horseflies and mosquitos; and now and then the heavy splash was heard, as they tossed their antlered heads into the stream, to free them from the venomous insects that buzzed incessantly about them. But in the sandy prairie, beetles of an enormous size were rolling in every direction huge balls of earth, pushing them with their hind legs with comical perseverance; cameleons darted about, assimilating the hue of their grotesque bodies with the colour of the sand: groups of prairie-dog houses were seen, each with its inmate barking lustily on the roof; whilst under cover of nearly every bush of sage or cactus a rattlesnake lay glittering in lazy coil. Tantalising the parched sight, the neighbouring peaks of the lofty