Popular Science Monthly/Volume 50/November 1896/On the Crater of Mount Shasta
|ON THE CRATER OF MOUNT SHASTA.|
AT one o'clock on an August morning in 1877 I found myself on the stage bound for Sissons, in Strawberry Valley, a bit of civilization nestled among the pines and redwoods twenty miles from the summit of Mount Shasta. The stage road wound through mountain passes and interminable forests of pines, following up the Sacramento River, here a torrential stream. A turn in the road once gave us a magnificent view of the Shasta cone, rising in a sugar-loaf shape, white as Carrara marble, and seeming to lift itself out of the forest on the right, though it was fifty miles distant.
At Sissons both the cone, which rises to an elevation of 14,440 feet above the Pacific, and its crater to the northwestward, which is about two thousand feet lower, were very distinct. The cone rises about four thousand feet above the timber line, and we could see the rough lava flows and ash fields lying between the summit and the upper edge of the timber belt.
Throughout the woods on the sides of the volcano bears and mountain lions abounded; our driver told me he saw one of the latter walking by the roadside a month previous. We saw deer far up in the woods; antelope range near the summit, and Rocky Mountain sheep, or bighorn, herd in the less accessible cliffs; while some time previous one of that rare and very shy mammal, the Rocky Mountain goat, which inhabits the more inaccessible ranges above the timber line, had been shot.
The view of the mountain that evening by moonlight was very fine. A light, silvery-edged cloud rested on the summit, while the mountain mass below, lighted up by the moonbeams, contrasted with the vast expanse of dark, somber forests in the foreground.
The next day was not favorable for the ascent, but it passed quickly. The forest scenes, enlivened by an encampment of Indians, in the rear of the inn, the rushing mountain torrents, the volcanic cones, or Black Buttes, to the northward, with their lavas, the old moraines, the insect life, all were novel features to an Eastern eye.
It cleared off at sunset; the clouds disappeared, leaving a thin veil of fresh snow on Shasta's peak and crater, now bathed in a ruddy glow, which, as the evening wore on, was replaced by the silvery light of the full-orbed moon.
The 25th was a glorious day, and in the bracing northerly breeze we started on our ride of twenty miles to the camping ground above the timber line. A distance of five or six miles through forests of magnificent oaks, pines, and redwoods brought us to "The Devil's Garden," which, far from being sulphurous in tone, is a large terminal moraine stretching eight miles west of the crater; the sides slope at a high angle, and the surface, like that of our kames in the Eastern States, is flat and of even width, being a quarter to half a mile wide. It looked at first like a lava stream, but the angular blocks of hornblende andesite intermingled with the débris bespoke its glacial origin. On the south of us ran down from the peak high, steep lateral moraines.
Passing above the limit of oak trees, we ascend above the belt of pitch pine and silver pines to the region of firs—speaking botanically, through the belt of Picea amabilis and then higher up to P. nobilis and P. contorta, then to a growth of P.flexilis, which attains an elevation of about ten thousand feet. With these, though mostly in the lower belts, were associated the characteristic shrubs of California, the Manzanita and Ceanothus, also a yellow-flowered, stiff plant like greasewood, which ascends far above the limit of trees. The silver-leafed P. contorta, near the upper edge of the timber line, grows from twenty to thirty feet high and from twelve to sixteen inches in diameter, with a very white bark. A zone of firs is situated between it and the highest pines. P. flexilis seems to be only a variety of P. contorta; it is more or less procumbent, lying down flat, covering yawning chasms or seams in the rough lava, so that one can walk upon the trunks and branches when they bridge the spaces between the angular, jagged blocks of lavas.
Late in the afternoon we selected a level place near a bank of snow at an elevation of about nine thousand five hundred feet, and, gathering a few logs of dead pines, we made a rousing fire, and atunrolled our heavy California blankets, sleeping nearer the stars than I ever had before. It was a clear, cold night; the water froze nearly an inch thick, and at 6.15 the next morning, when we began our ascent of the crater, the thermometer was 25° F.
We rode our horses for an hour until we came to the foot of the ash cone, and by 8.45 were on the summit of the crater. The view in the clear atmosphere was indeed a wide one. Far to the northwest was the Siskiyou range and Pilate's Knob, and to the west the jagged, saw-toothed, snowy peaks of the Salmon Mountains; fifty miles southward was the snow-clad solitary Lassens Peak, twelve thousand feet high; while Klamath Lakes and the lava beds, the seat of the late Modoc war, lay to the northeast-ward.
The scene was a wild one within the great crater, whose narrow edge is formed of sharp, jagged peaks and pinnacles. Broad, almost unbroken snow fields extended from the edge down for a thousand feet; at the bottom were two frozen lakes like sheets of glass. The crater was extinct, no signs of steam or of recent eruptions meeting the eye. We were told that on the summit of the cone there is a hot-steam vent, the last dying embers of past volcanic action. Mr. Sissons, while guiding a traveler to the summit, was once belated and had to spend the night there, and saved the lives of himself and his companion by lying close to the steam vent, the steam passing up through the snow. On their descent they slid down over the snow fields of the summit to the lava beds below.
The outlet of the crater, or point of overflow at the last eruption, was on the western side, where small masses of black obsidian and white incrustations of lime were observed.
Turning away from this wonderful view, we walked over the snow and down the loose rocky sides to a rock overlooking the Whitney Glacier. This ice stream, which stretched uphill past the crater to its source, is about three miles long, and on the north side of the mountain, at a point about 13,500 feet high, it heads in a snow field, or mer-de-glace, which is continuous with the head of the McCloud Glacier. Toward the top a large mass of lava projects above the surface of the ice, which is white and very clear near the top; but below this point the glacier is much discolored, more so than any Alpine glacier I have seen. Owing to the steep and uneven pitch of the rocky bed, the surface of the ice, especially near the upper end of the glacier "cascades," or breaks into needles, being rent by numerous crevasses. On each side is a well-marked lateral moraine, with its steepest side next to the overhanging wall of lava; the moraine on the western side begins much lower down. The one on the east side ends in three ridges of dirt and rock, the two uniting to form the great terminal moraine, and, looking far down the glacial stream, this moraine was seen to pass under the ice, or rather the ice overrode it, since the glacier was seen here and there to project above it. Large bowlders or blocks of lava were scattered over it, and its surface was very uneven, with irregular mounds of débris and deep pit-holelike hollows or basins between them. The terminal moraine was overlooked by a small volcano or monticule perhaps a thousand feet high, with nine or ten crater cones rising from its sides—a beautiful example, and reminding me, as I remember them, of the monticules on the flanks of Mount Etna.
At and beyond the end of the present terminal moraine stretches away in the distance a number of old moraines, naked and bare as when they were born, forming plains and overlooked by well-wooded hills. A rapid stream with a white bed runs from the end of the glacier in a northerly direction into Shasta Valley, and at night it is not frozen.
On the northeastern side near the end of the glacier are three well-marked naked old moraines at least two miles in length, which sweep round to the volcano above referred to, and apparently connect with the terminal moraine of a small narrow glacier just east of the Whitney Glacier, and which may formerly have been an upper eastern branch of it. This, perhaps, is the Ash Creek Glacier, which lies on the northeast slope of the mountain, while the McCloud Glacier lies farther to the eastward.
The terminal moraines at the end of the Whitney Glacier, which are not, as in Swiss glaciers, clearly demarked from the end of the glaciers themselves, but form an exceedingly irregular and broken field of rocks and débris covering and burying the ice, with many sinks or basins and "kettles," enabled me to clearly understand the mode of formation of the "kettles" or deep holes, at times still filled with water, which are so marked in Massachusetts, near Salem and Marblehead, and also at the "Dumplings" on Canonicut Island near Newport, Rhode Island.
In his account of the McCloud Glacier of Mount Shasta in his entertaining Mountaineering in the Sierra Nevada, Mr. Clarence King states that for "at least a mile's width the whole lower zone is buried under accumulation of morainal matter. Instead of ending like most Swiss glaciers, this ice wastes chiefly in contact with the ground, and when considerable caverns are formed the overlying moraine crushes its way through the rotten roof, making the funnels we had seen."
These immense fields of morainal matter overlying and burying the melting edge of the glacier, here spreading out over the lower flanks of the mountain, were evident signs of the waning of the ice, the glacier having long since ceased to advance; and it enabled me, as never before, to understand that the peculiar hills and basins or kettles of the great terminal moraine of southern New England were formed by the irregular melting of the southern edge of the glacier, when through and under the mass of ice, perhaps not over from three to five hundred feet thick, ran subglacial streams and rivers, while here and there, owing to the uneven melting of the ice, immense masses of gravel and bowlders had fallen in, the material adjoining being rearranged into rounded kames, so characteristic of our New England scenery.
The rocks on the eastern side of the middle portion of the Whitney Glacier were rounded and polished, as much as such hard rock could well be, when the glacier was of greater volume than now. At present the ice has melted away from the sides of the rock overlooking it. So far as I could see from my point of view, the surface was not grooved or striated.
That the glacier was in motion was proved by the not infrequent distant explosions caused by the rupture of the ice near the head of the glacier. The general appearance of things indicated that the glacier was diminishing in size, and Sissons told me that the surface of the glacier was at least from seventy-five to one hundred feet lower than at the time of his last visit, four years previous.
We lunched on the rim of the crater, at 3 p. m. went down to where we had left our horses, and after a hard and fatiguing though glorious ride of four hours reached the hotel ranch.
We found that the crater cone is composed of a reddish lava, while the mother peak rising far above it is formed of a hard, bluish trachyte. Its moraines extend for ten to twelve miles down the western slope, passing beyond the west side of the stage road north of Sissons, where more or less rounded hillocks of this bluish trachyte abut on the hills of metamorphic rocks of the Trinity and Sacramento Mountains.
We also saw as we descended that the large moraine extending from the cone ending in the "Devil's Garden" is flanked by two lateral moraines, the median one, or the garden, extending from the base of the crater cone. What adds to the singularity and wildness of the scene at the upper end of this "garden," or rather playground of mountain imps, are the numerous parallel concentric ridges of lava rock, forming a succession of transverse terminal moraines, with benches of clear soil between them. These parallel curved rows of stones and angular gravel mark the rapid retreat and melting away of the glacier, which, with its neighbor, extended down on the western slope.
To my disappointment, I found no Alpine fauna or flora on the summit of the crater, and believe there is none on the main peak. The vegetation was very scanty where we camped, only grasses and plants which had straggled up from below, and, so far as I remember, nothing but lichens occurred on the bare rocks and moraines above. No Alpine or arctic butterflies or moths occurred, such as I was familiar with, and which abound on the summits of the Rocky Mountains. A few spiders, a small centipede (Lithobius), and a few ants' nests were to be seen, and under stones a bristle-tail (Machilis), but the only distinctive Alpine insect on the mountain was a wingless grasshopper (Pezotettix), though that occurred lower down, in the zone of firs. I saw a common Pieris butterfly at the top of the crater, but this was like one seen flying below.
This entire lack of any Alpine plants or animals indicates that Mount Shasta is too young and isolated a mountain to have been reached by any waifs from arctic or Alpine sources, and their absence suggests that the glaciers had at a very recent date melted away and disappeared from the western side of the mountain.
But that the whole massif or mountain mass had once been enshrouded by the ice of a late glacial epoch was proved by the existence among the farms of Strawberry Valley, some ten miles in a direct line from the summit, of two well-rounded hills or flattened domes of a supposed metamorphic rock which had evidently been regularly molded by ice.
This was further proved to our own satisfaction the next day after our descent, in riding on the stage from Berryvale to Butteville. Directly beyond the hotel is a remarkable terminal moraine evidently derived from the crater, as it is composed of small bowlders of reddish-brown lava; these are arranged in transverse, curved parallel rows on the plain, with clear grass-grown spaces between them, much as in the larger, higher ones in the "Devil's Garden" moraine, but the bowlders are very much smaller and less angular. This point is about twenty-five hundred feet above the sea, and about fifteen or twenty miles from the summit of the crater. Hence the ice seems to have extended from the snow fields of Shasta's summit down upon the plains, where it apparently abutted on the Trinity and Sacramento ranges, which were probably below the ice belt and not glaciated.
From Butteville the view of Mount Shasta is incomparably fine—one of the world's great views. Looking from this point, the cone is in line with the mother peak. The great cone or mountain mass rises as a unit from a broad, treeless plain dotted with scattered ranches and pierces the clouds. Above this plain, as the afternoon waned and the evening shades fell, the zone of black firs and pines merged into a region of dark purple, becoming more ruddy above, until the last beams of the setting sun tinged and flushed the snowy summit with an Alpine glow. As these pink and reddish tints faded away, the dark purple mass of color rose higher and higher until the darker shades of evening completely enshrouded it, and finally as the darkness fell the cone lost its height and distinctness.