in these rich pastures, but the buffalo has been driven away. When, in 1844, Fremont visited the South Park, herds of these animals blackened the surface, and their well-beaten trails afforded the most practicable route through the region; but now they do not even approach the foothills.

The Utes use these parks during the summer as cow lodges, but as winter approaches the herd is driven down to the plain.

GEOLOGY. To comprehend the geology of the Rocky Mountains, where the forces of metamorphism have been so powerfully exerted, it is necessary at the same time to study the geology of the Plains, where the strata repose nearly horizontally, and are abundantly charged with fossils. Starting at Kansas City, we first encounter the Coal Measures, which continue to Fort Riley. Here occurs a drab-colored limestone associated with marls, which is regarded as the equivalent of the Permian. Next succeeds a series of bright red and green marls, seen at Salina, which may be Triassic. Above this formation comes the Cretaceous occupying a broad zone nearly coterminous with the plains, conspicuously displayed at Ellis, Fossil Creek, and Fort Wallace. The Miocenetertiary abuts against the foothills and extends to the east of Denver. At Golden City, the strata of this formation are tilted up vertically, thus showing that within comparatively recent times, this region has been subjected to violent displacements. It is characterized by heavy deposits of coal (lignite) which is successfully mined at Golden City, on Ralston's Creek, South Boulder and other streams descending from the mountains. The beds are from ten to fourteen feet thick-an undue expansion which would indicate that they are pockets, instead of persistent seams. The coal is bright and glossy, but crumbles on exposure to the air, and even when burned in a grate. It contains from twelve to fifteen per cent. of hygrometric moisture which must be expelled in combustion at the expense of the fixed carbon, and therefore prevents it from acquiring that concentrated heat necessary in metallurgic operations. It answers well for household purposes and for locomotives, and in such a region where wood is scarce, its economical value can hardly be over estimated.

As we enter the foothills, layers of brick-red sandstone are observed which, although destitute of fossils, Hayden is disposed to regard as Jurassic. There is also seen a drab-colored limestone,

used at Denver for building purposes, which Hayden regards as Carboniferous. Although ripple-marked, I observed no fossils. Both of these deposits are highly metamorphosed and the strata stand nearly vertical.

Next succeeds a vast series of gneissoidal rocks in which feldspar and mica are the predominant minerals. These rocks everywhere show lines of bedding, but they have been plicated, shattered and tilted up at all angles, and at the same time are cut by numerous divisional planes. The metamorphism of the mass is so complete as to have obliterated all traces of fossils and to have changed the mechanical structure of the rocks themselves. Perhaps there is no region on the continent where the action of igneous causes is displayed on so grand a scale as here.

The true granites are only seen along the axes of elevation. They play an important part in the structure of the region, constituting, as it were, its framework.

In the Rocky Mountain system is probably represented the whole assemblage of formations from the Azoic up to and including the Jurassic, but so thorough has been the processes of metamorphism, at least on the Atlantic slope, that it is impossible to recognize subordinate groups. On the western slope, Fremont long ago recognized rocks with organic remains, which he referred to the Oölite, which is a member of the Jurassic. The investigations of Whitney in California have settled this question-that it was at the close of the Jurassic epoch that this vast assemblage of formations was metamorphosed and folded into great ridges with their intervening valleys. The eruptive rocks accompanying this upheaval were for the most part granites, probably in a pasty condition, as in this association there are no traces of volcanic prod-, ucts.

VEIN PHENOMENA. It was at this time that the granites and metamorphic rocks became impregnated with the precious metals, such as gold and silver, which are found concentrated in veins and fissures. At a subsequent date-during the earlier Tertiary Period-a series of volcanic vents were formed along the line of previous disturbance, from which were poured forth a series of igneous products, such as basalts, lavas, etc. These also became impregnated with the precious metals, of which the famous Comstock lode in Nevada, as shown by Richthofen, is a notable example. Thus,

then, the formation of the mineral veins of this region may be referred to two distinct epochs.

The veins of Colorado, thus far mined, belong to the older class. The gold-bearing veins, unlike those of California, contain in their gangues, copper and iron pyrites, blende and galena, and so intimately is the gold connected with these sulphurets, that great loss is incurred in its extraction.

The veins of silver have, also, their associations of base sulphurets, and the silver itself appears under the forms of sulphuret and antimonial. Black Hawk and Central City are the main sites of gold mining, while Georgetown is the focus of silver mining. The annual product in the precious metals as estimated by Clarence King is about three million, two hundred and fifty thousand dollars. As constituting a part of the volcanic phenomena, may be mentioned the frequent occurrence of hot springs throughout the whole area occupied by this mountain system. In Colorado, the most noted are those of Middle Park and Idaho. The former are not readily accessible, and I am not aware that their waters have been subjected to analysis. The latter are now resorted to for their remedial virtues in cases of rheumatism, paralysis, and cutaneous affections. These springs issue from the left bank of Soda Creek, and are three in number. The flow is not copious, being about ten gallons a minute. The temperature is 109° F. An analysis of the water by Mr. J. G. Pohle of New York, gave one hundred and seven grains of solid matter to the gallon, made up of the following ingredients:

CLIMATE. One of the most striking peculiarities of these mountains is the absence of a perpetual line of congelation. Mr. Bowles in his little work on this region, calls special attention to this significant fact, and points out the diversities between these mountains and those of Switzerland; and what I propose to state under

this head will be but an amplification of this train of thought. It is true that in midsummer even large snow-fields are to be seen, but it is the result of the winter's accumulation in the ravines and other places sheltered from the sun. Above the snow-patches the grasses thrive and the delicate lichens in thin flat crusts adhere to the rocks which form the dominating peaks. The tree-line ascends to eleven thousand feet. Potatoes, beets and cabbages and the hardier cerealia, such as oats and barley, are successfully cultivated at nine thousand feet; at ten thousand feet flowers bloom, often sending forth their petals close by a snow-bank. Thus January and May are commingled. Thriving under such conditions. is a wild columbine which clusters in large patches and bears a deep purple blossom fringed with white. This profusion of gaudy flowers arrested the attention even of the untutored savage, and the Utes gave to the plant the name of idaho or purple flower. The white explorers applied this name to a town, which they founded on the banks of Clear Creek in Colorado, and a band of miners swarming thence to a region farther north, carried with them this name, which subsequently became attached to a territory of the United States.

During the summer, day after day, the sun comes up without a cloud; but midday passed, there is an afternoon mist, often accompanied by thunder and lightning. At Denver the phenomena of gusts of wind and thunder and lightning are of almost daily occurrence, and yet without a drop of rain. During the month of July last, the precipitation was fifty-one one-hundreths of an inch. In the mountains there are "cloud bursts," when the rains fall in a cataract and filling the gulches sweep every thing before them.

The electrical phenomena often occurring during a storm on the summits of the mountains are most vivid, and dangerous to those caught in such exposed positions. There are authentic instances where the body becomes so surcharged with electricity that the hair stands out rigidly, and sparks are emitted from the person thus isolated when approached, and every metallic article becomes luminous.

Statistics as to the amount of rainfall in the montains have not been collected, but at Denver it only reaches about thirteen inches during the year.

In that dry and bracing atmosphere the thermometer may rise to ninety degrees F. and yet without producing those depressing

effects experienced in a more humid climate. Perspiration is almost insensible. The residents represent that autumn is the pleasantest portion of the year, and that this delicious season continues until January, when the winter seriously sets in and continues until May. The snows are not deep, and on the cliffs exposed to the direct rays of the sun rarely remain over a few days. Such is the climate in the cañons, but on the higher peaks a mantle of white begins to form late in September and continues to accumulate until spring.

The temperature at Denver, two thousand, one hundred and five feet above the sea, does not differ essentially from that at Cambridge, Massachusetts, seventy-one feet above the sea, while the difference of latitude is about two degrees. This is shown in the subjoined table:

Mt. Washington, in New Hampshire, is six thousand six hundred feet above the sea, and the little band of observers who last year passed the winter upon its summit, encountered all the rigors of an arctic climate. At Idaho Springs, in the heart of the Colorado Mountains, and one thousand one hundred and forty-two feet higher, cattle may pass the winter without shelter. A warm breath permeates the valleys, mitigating the severity of winter, and rendering the climate agreeable to the human system. I will not pause to discuss the causes of this anomaly, so at variance with what is observed in other regions lying within the temperate

zone.

If we turn to the Alps, from which we naturally derive our ideas of the effects of temperature by reason of elevation, we shall find that far different conditions prevail. At the height of eight thousand feet the line of perpetual snow is encountered, and not less than four hundred glaciers exist, extending over an area of fourteen hundred square miles. Mt. Blanc, fifteen thousand, seven hundred and forty-four feet above the sea, about fifteen hundred feet higher than several of the Colorado Peaks, is scaled only by cut