After travelling about ten miles we struck a wagon-trail, which evidently had been made several years. From the indentations of the wheels, where the earth was soft, five or six wagons had passed here. The appearance of this trail in this desolate region was at first inexplicable; but I soon recollected that some five or six years ago an emigrating expedition to California was fitted out by Colonel Bartlettson, Mr. J. Chiles, and others, of Missouri, who, under the guidance of Captain Walker, attempted to enter California by passing round the southern terminus of the Sierra Nevada; and that they were finally compelled to abandon their wagons and every thing they had, and did not reach their destination until they had suffered incredible hardships and privations. This, it appeared to me, was evidently their trail; and old as it was, and scarcely perceivable, it was nevertheless some gratification to us that civilized human beings had passed here before, and left their mark upon the barren earth behind them. My conjectures, above stated, have been subsequently confirmed by a conversation with Mr. Chiles. Following this old trail some two or three miles, we left it on the right, and crossed some low and totally barren hills, which appear to have been thrown up by the action of volcanic fires at no very remote period of geological history. They are composed of a white, imponderous earth, resembling ashes, intermingled with fragments of scoria, resembling the cinders from an iron-foundry, or a blacksmith's furnace. A vitreous gravel, or glass, was also thickly strewn over the surface, and glittered brightly in the sunbeams.