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John Muir: Wilderness Essays, Environmental Studies, Memoirs & Letters (Illustrated Edition). John Muir
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isbn 9788075838155
Автор произведения John Muir
Жанр Книги о Путешествиях
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IV. Mount Shasta
1) Summer Days at Mount Shasta
Mount Shasta rises in solitary grandeur from the edge of a comparatively low and lightly sculptured lava plain near the northern extremity of the Sierra, and maintains a far more impressive and commanding individuality than any other mountain within the limits of California. Go where you may, within a radius of from fifty to a hundred miles or more, there stands before you the colossal cone of Shasta, clad in ice and snow, the one grand unmistakable landmark -- the pole star of the landscape. Far to the southward Mount Whitney lifts its granite summit four or five hundred feet higher than Shasta, but it is nearly snowless during the late summer, and is so feebly individualized that the traveler may search for it in vain among the many rival peaks crowded along the axis of the range to north and south of it, which all alike are crumbling residual masses brought into relief in the degradation of the general mass of the range. The highest point on Mount Shasta, as determined by the State Geological Survey, is 14,440 feet above mean tide. That of Whitney, computed from fewer observations, is about 14,900 feet. But inasmuch as the average elevation of the plain out of which Shasta rises is only about four thousand feet above the sea, while the actual base of the peak of Mount Whitney lies at an elevation of eleven thousand feet, the individual height of the former is about two and a half times as great as that of the latter.
Approaching Shasta from the south, one obtains glimpses of its snowy cone here and there through the trees from the tops of hills and ridges; but it is not until Strawberry Valley is reached, where there is a grand out-opening of the forests, that Shasta is seen in all its glory. From base to crown clearly revealed with its wealth of woods and waters and fountain snow, rejoicing in the bright mountain sky, and radiating beauty on all the subject landscape like a sun. Standing in a fringing thicket of purple spiraea in the immediate foreground is a smooth expanse of green meadow with its meandering stream, one of the smaller affluents of the Sacramento; then a zone of dark, close forest, its countless spires of pine and fir rising above one another on the swelling base of the mountain in glorious array; and, over all, the great white cone sweeping far into the thin, keen sky -- meadow, forest, and grand icy summit harmoniously blending and making one sublime picture evenly balanced.
The main lines of the landscape are immensely bold and simple, and so regular that it needs all its shaggy wealth of woods and chaparral and its finely tinted ice and snow and brown jutting crags to keep it from looking conventional. In general views of the mountain three distinct zones may be readily defined. The first, which may be called the Chaparral Zone, extends around the base in a magnificent sweep nearly a hundred miles in length on its lower edge, and with a breadth of about seven miles. It is a dense growth of chaparral from three to six or eight feet high, composed chiefly of manzanita, cherry, chincapin, and several species of ceanothus, called deerbrush by the hunters, forming, when in full bloom, one of the most glorious flowerbeds conceivable. The continuity of this flowery zone is interrupted here and there, especially on the south side of the mountain, by wide swaths of coniferous trees, chiefly the sugar and yellow pines, Douglas spruce, silver fir, and incense cedar, many specimens of which are two hundred feet high and five to seven feet in diameter. Goldenrods, asters, gilias, lilies, and lupines, with many other less conspicuous plants, occur in warm sheltered openings in these lower woods, making charming gardens of wildness where bees and butterflies are at home and many a shy bird and squirrel.
The next higher is the Fir Zone, made up almost exclusively of two species of silver fir. It is from two to three miles wide, has an average elevation above the sea of some six thousand feet on its lower edge and eight thousand on its upper, and is the most regular and best defined of the three.
The Alpine Zone has a rugged, straggling growth of storm-beaten dwarf pines (Pinus albicaulis), which forms the upper edge of the timberline. This species reaches an elevation of about nine thousand feet, but at this height the tops of the trees rise only a few feet into the thin frosty air, and are closely pressed and shorn by wind and snow; yet they hold on bravely and put forth an abundance of beautiful purple flowers and produce cones and seeds. Down towards the edge of the fir belt they stand erect, forming small, well-formed trunks, and are associated with the taller two-leafed and mountain pines and the beautiful Williamson spruce. Bryanthus, a beautiful flowering heathwort, flourishes a few hundred feet above the timberline, accompanied with kalmia and spiraea. Lichens enliven the faces of the cliffs with their bright colors, and in some of the warmer nooks of the rocks, up to a height of eleven thousand feet, there are a few tufts of dwarf daisies, wallflowers, and penstemons; but, notwithstanding these bloom freely, they make no appreciable show at a distance, and the stretches of rough brown lava beyond the storm-beaten trees seem as bare of vegetation as the great snow fields and glaciers of the summit.
Shasta is a fire-mountain, an old volcano gradually accumulated and built up into the blue deep of the sky by successive eruptions of ashes and molten lava which, shot high in the air and falling in darkening showers, and flowing from chasms and craters, grew outward and upward like the trunk of a knotty, bulging tree. Not in one grand convulsion was Shasta given birth, nor in any one special period of volcanic storm and stress, though mountains more than a thousand feet in height have been cast up like molehills in a night -- quick contributions to the wealth of the landscapes, and most emphatic statements, on the part of Nature, of the gigantic character of the power that dwells beneath the dull, dead-looking surface of the earth. But sections cut by the glaciers, displaying some of the internal framework of Shasta, show that comparatively long periods of quiescence intervened between many distinct eruptions, during which the cooling lavas ceased to flow, and took their places as permanent additions to the bulk of the growing mountain. Thus with alternate haste and deliberation eruption succeeded eruption, until Mount Shasta surpassed even its present sublime height.
Then followed a strange contrast. The glacial winter came on. The sky that so often had been darkened with storms of cinders and ashes and lighted by the glare of volcanic fires was filled with crystal snow-flowers, which, loading the cooling mountain, gave birth to glaciers that, uniting edge to edge, at length formed one grand conical glacier -- a down-crawling mantle of ice upon a fountain of smouldering fire, crushing and grinding its brown, flinty lavas, and thus degrading and remodeling the entire mountain from summit to base. How much denudation and degradation has been effected we have no means of determining, the porous, crumbling rocks being ill adapted for the reception and preservation of glacial inscriptions.
The summit is now a mass of ruins, and all the finer striations have been effaced from the flanks by post-glacial weathering, while the irregularity of its lavas as regards susceptibility to erosion, and the disturbance caused by inter- and post-glacial eruptions, have obscured or obliterated those heavier characters of the glacial record found so clearly inscribed upon the granite pages of the high Sierra between latitude 36 degrees 30 minutes and 39 degrees. This much, however, is plain: that the summit of the mountain was considerably lowered, and the sides were deeply grooved and fluted while it was a center of dispersal for the glaciers of the circumjacent region. And when at length the glacial period began to draw near its close, the ice mantle was gradually melted off around the base of the mountain, and in receding and breaking up into its present fragmentary condition the irregular heaps and rings of moraine matter were stored upon its flanks on which the forests are growing. The glacial erosion of most of the Shasta lavas gives rise to detritus composed of rough subangular boulders of moderate size and porous