intra-montane plateaus. It occupies a surface of about fifty miles square; is as smooth as an Illinois prairie; and the sensation of finding such a lowland tract at the height of eight thousand feet in the air, is a bewilderment to all one's previous notions of physical geography. The plateau is an alluvial deposit, belonging, so far as I could learn from a perpendicular section on the west bank of Big Laramie River, to the late tertiary. This appeared to consist of alternating white and yellow striæ, representing two varieties of silt, the former almost purely cretaceous, the latter partly so, but mostly composed of alumina with a tinge of red oxide of iron or chromium. I nowhere noticed an outcrop of rocks belonging to the mountain system. The grass was nearly as luxuriant and green as a New England June meadow. Its level in the general view seemed uniform as the sea; and such special deviations as occurred here and there, were not of the ordinary rolling contour proper to the Plains, but rather seemed terrace formations. To understand the strangeness of such a landscape in such a position, it must be remembered that this vast plain not only stands at an elevation of eight thousand feet, but is walled on all sides by mountains nearly as much higher than itself. Just as we enter the Plain by its eastern boundary coming from Cheyenne Pass, we catch a glorious glimpse of the Laramie Butte, its snow shining like a white-hot mass in the dazzling sunlight; its form almost a perfect cone, its height rated among the loftiest snow-peaks of the range. It stands as a sort of northeastern bastion to the enor mous square, and from it, westward, lead the giant ramparts of the Wind River range, with an occa

Bional snow-crowned turret, towards Fremont's and Lander's Peaks. On the southern side of the plateau, in a direction nearly parallel to the Wind River chain, runs a long black range of rolling mountains, three or four thousand feet high above the Plains level, bare as the bumps on a phrenologist's cast, and possessing the rounded contour which I had found associated with rotten granite. Behind us the square is almost closed by the time we reach the lowest bottom, through the intervention of those crags and cones we have left around Virginia Dale. To the due westward rises a succession of rugged granite stairs climbing up to the mighty Medicine Bow Mountains, under whose snows we shall shiver to-morrow; and from the middle of the Plains, through a gap at the southwestern corner of our bounding walls, we get the most ravishing view of distant snow-ranges that was ever vouchsafed Nature's lover in this world. I have seen many isolated peaks which surpassed those of this particular view, but I never in my life imagined equal beauty in a range itself. These mountains belonged to the Uintah system, another transverse range like the Wind River, running from Green River, near the 109th parallel of longitude, to inosculate with the Wahsateh range near Utah Lake. This was our first view of Mormondom; and I could not wonder that when that strange company of enthusiasts, led by Brigham Young, caught such a glimpse as this of the land beyond them, they were filled with an ecstasy which spent itself in prayers, dreams, and prophesyings. I can think of no resemblance for it, save my childish. impressions of an old steel engraving, called "The Mount of God." Mature taste may condemn such prints with the nightmares of Fuseli and the resurrec

tions of Martin; but my propensity for the marvelous was too much gratified to let me be critical. So was it here. The view was not explicable by the ordinary ideals of terrestrial scenery; it was a fairy phantasm, a floating cloud, a beatific dream of paradisaical ranges, let down out of heaven, not builded out of earth. The sunlight fell on it out of a spotless sky; every square inch of the range received its maximum of illumination, so that its shadows were only less relieved against greater lights, and seemed spots of vague turquoise, sapphire, or pale amethyst on a floating mist of diamond or opal vapor. These gross comparisons come as near the impression as words of mine can; but my reader must take a step in idealism for himself, and imagine all these gems glorified by distance into the spirits of themselves. The nearest peaks of the Uintah were at least a hundred miles from us, and rose from a lower level than ourselves; yet none of us needed to be told that they were among the grandest of the whole Cordillera. They vindicated themselves to the kingly title by the ermine of snow and the diamonds of ice, together making them one continuous splendor half way from foot to crest.

Our way lay across the southern third of the level. On each side of us the grass was luxuriant, and everywhere a nearer approach to Eastern meadows in its greenness than any of the herbage on the Plains proper. There were no settlements visible except at the stations; and these consisted merely of the buildings demanded by the road. We passed several large trains of cattle-wagons, all of them belonging to Gentile emigrants (the Mormon trains preferring the northern or Laramie route); and in one place, where

they had halted for the day, the camp, with its snowy wagon-tilts, its leaping fires, its picturesque backwoodsmen, women, and children, and the oxen browsing or lying down in the sweet thick grass, made a very pretty spectacle.

The Indian still has free range over this delightful plain. The antelope abounds on it; every variety of grouse found in the range is plenty here; deer, bear, and elk are numerous in the fastnesses of the surrounding mountains; and so long as the sun shines warm, no tract can be a better antetype of the Indians' happy hunting-grounds. As if in recognition of this likeness, the tribes had here and there on the plain erected curious mausoleums for their departed braves, consisting of a high pole-staging, upon which the dead lay, wrapped in his blankets in the open air. In no case where we passed these strange monuments were we offended by odors of decomposition. This fact is one of the strongest illustrations of the character of the Rocky Mountain atmosphere, and especially of that. part of it which floats dissolved with the purest sunlight over Laramie Plains. The air is different from that on the eastern slope of the Appalachians very much in the same kind that muriatic acid differs from muriate of ammonia. Muriate of ammonia contains acid which has been contains oxygen in its passive state. There are some localities in the mountains where the ozone tests fail of a discovery for months at a time; throughout the mountains, and a distance of many miles eastward on the Plains, iron lies out-of-doors a year at a time without perceptible rusting; such consumptives as come to this region, and settle no higher up the range than they can preserve their ease of respiration, find

satisfied: the air

their disease remarkably retarded. There are several theories looking toward an explanation of the passive oxygen accumulated toward the centre of the Continent. It has been found that the air interpolated between water globules contains a much higher per cent. of active oxygen. The vapor of the sea-board, on its way towards the Rocky Mountains, undergoes progressive condensation upon every eminence, alternating with rarefaction over every heated plain. Both the water that ascends into the higher stratum of clouds to be wafted westward for final condensation on the loftiest snow-peaks of the Rocky range, and that which falls in showers between the Appalachians, or the Gulf margin and the rainless regions of the Platte, contain between their globules a large per cent. of all the ozonized air which they have met in their passage through the atmosphere. Thus in either case, whether the ozone goes entangled with the water into the soil or the supra-human regions of the atmosphere, all the middle space occupied by the range and its neighboring plains has suffered a defiltration of its ozone. If this view of mine be correct, we may naturally look for a powerfully ozonized atmosphere on the highest peaks of the Rocky Mountains. Another theory suggests that the ozone of the sea-board atmosphere is only an allotropic condition of all the oxygen present resulting from the decomposition of sea-water, electrical currents created by the friction of dry and wet air, or from both, and that with the removal of these conditions, as by transportation inland, the oxygen returns to its passive, and, on this hypothesis, its normal state. I prefer the former view, as consistent with the experiments of Schönbein and his theory of the duplex constitution of aërial oxygen by a plus and a minus element.