Part 12

The climax of this spectacle is the Waterwheels. Granite obstructions in the bed of the steeply tilted river throw solid arcs of frothing water fifty feet in air. They occur near together, singly and in groups.

The fine camping country south of the Yosemite Valley also offers its sensation. At its most southern point, the park accomplishes its forest climax in the Mariposa Grove. This group of giant sequoias (Sequoia washingtoniana) ranks next, in the number and magnificence of its trees, to the Giant Forest of the Sequoia National Park and the General Grant grove.

The largest tree of the Mariposa Grove is the Grizzly Giant, which has a diameter of twenty-nine feet, a circumference of sixty-four feet, and a height of two hundred and four feet. One may guess its age from three thousand to thirty-two hundred years. It is the third in size and age of living sequoias; General Sherman, the largest and oldest, has a diameter of thirty-six and a half feet, and General Grant a diameter of thirty-five feet, and neither of these, in all probability, has attained the age of four thousand years. General Sherman grows in the Sequoia National Park, seventy miles or more south of Yosemite; General Grant has a little national park of its own a few miles west of Sequoia.

The interested explorer of the Yosemite has so far enjoyed a wonderfully varied sequence of surprises. The incomparable valley with its towering monoliths and extraordinary waterfalls, the High Sierra with its glaciers, serrated cirques and sea of snowy peaks, the Grand Canyon of the Tuolumne with its cascades, rushing river and frothing Waterwheels, are but the headliners of a long catalogue of the unexpected and extraordinary. It only remains, to complete this new tale of the Arabian Nights, to make one's first visit to the sequoias of Mariposa Grove. The first sight of the calm tremendous columns which support the lofty roof of this forest temple provokes a new sensation. Unconsciously the visitor removes his hat and speaks his praise in whispers.

The sequoias are considered at greater length in the chapter describing the Sequoia National Park, which was created especially to conserve and exhibit more than a million of these most interesting of trees. It will suffice here to say that their enormous stems are purplish red, that their fine, lace-like foliage hangs in splendid heavy plumes, that their enormous limbs crook at right angles, the lowest from a hundred to a hundred and fifty feet above the ground, and that all other trees, even the gigantic sugar pine and Douglas fir, are dwarfed in their presence. Several of the sequoias of the Mariposa grove approach three hundred feet in height. The road passes through the trunk of one.

The human history of the Yosemite is quickly told. The country north of the Valley was known from early times by explorers and trappers who used the old Mono Indian Trail, now the Tioga Road, which crossed the divide over Mono Pass. But, though the trail approached within a very few miles of the north rim of the Yosemite Valley, the valley was not discovered till 1851, when Captain Boling of the Mariposa Battalion, a volunteer organization for the protection of settlers, entered it from the west in pursuit of Indians who had raided mining settlements in the foothills.

These savages were known as the Yosemite or Grizzly Bear Indians. Tenaya, their chief, met their pursuers on the uplands and besought them to come no further. But Captain Boling pushed on through the heavy snows, and on March 21, entered the valley, which proved to be the Indians' final stronghold. Their villages, however, were deserted.

The original inhabitants of the Valley were called the Ahwahneechees, the Indian name for the Valley being Ahwahnee, meaning a deep grassy canyon. The Ahwahneechees, previous to Captain Boling's expedition, had been decimated by war and disease. The new tribe, the Yosemites, or Grizzly Bears, was made up of their remainder, with Monos and Piutes added.

Captain Boling's report of the beauty of the valley having been questioned, he returned during the summer to prove his assertions to a few doubters. Nevertheless, there were no further visitors until 1853, when Robert B. Stinson of Mariposa led in a hunting-party. Two years later J.M. Hutchings, who was engaged in writing up the beauties of California for the California Magazine, brought the first tourists; the second, a party of sixteen, followed later the same year.

Pleasure travel to the Yosemite Valley may be said to have commenced with 1856, the year the first house was built. This house was enlarged in 1858 by Hite and Beardsley and used for a hotel. Sullivan and Cushman secured it for a debt the following year, and it was operated in turn by Peck, Longhurst, and Hutchings until 1871. Meantime J.C. Lamon settled in 1860, the first actual resident of the valley, an honor which he did not share with others for four years.

The fame of the valley spread over the country and in 1864 Congress granted to the State of California "the Cleft or Gorge of the Granite Peak of the Sierra Nevada Mountains" known as the Yosemite Valley, with the understanding that all income derived from it should be spent for improving the reservation or building a road to it. The Mariposa Big Tree Grove was also granted at the same time. California carefully fulfilled her charge. The Yosemite Valley became world-famous, and in 1890 the Yosemite National Park was created.

VII

The Yosemite's geological history is much more thrilling. Everyone who sees it asks, How did Nature make the Yosemite Valley? Was it split by earth convulsions or scooped by glacier? Few ask what part was played by the gentle Merced.

The question of Yosemite's making has busied geologists from Professor Whitney of the University of California, who first studied the problem, down to F.E. Matthes, of the United States Geological Survey, whose recent exhaustive studies have furnished the final solution. Professor Whitney maintained that glaciers never had entered the valley; he did not even consider water erosion. At one time he held that the valley was simply a cleft or rent in the earth's crust. At another time he imagined it formed by the sudden dropping back of a large block in the course of the convulsions that resulted in the uplift of the Sierra Nevada. Galen Clark, following him, carried on his idea of an origin by force. Instead of the walls being cleft apart, however, he imagined the explosion of close-set domes of molten rock the riving power, but conceived that ice and water erosion finished the job. With Clarence King the theory of glacial origin began its long career. John Muir carried this theory to its extreme.

Since the period of Muir's speculations, the tremendous facts concerning the part played by erosion in the modification of the earth's surface strata have been developed. Beginning with W.H. Turner, a group of Yosemite students under the modern influence worked upon the theory of the stream-cut valley modified by glaciers. The United States Geological Survey then entered the field, and Matthes's minute investigations followed; the manuscript of his monograph has helped me reconstruct the dramatic past.

The fact is that the Yosemite Valley was cut from the solid granite nearly to its present depth by the Merced River; before the glaciers arrived, the river-cut valley was twenty-four hundred feet deep opposite El Capitan, and three thousand feet deep opposite Eagle Peak. The valley was then V-shaped, and the present waterfalls were cascades; those which are now the Yosemite Falls were eighteen hundred feet deep, and those of Sentinel Creek were two thousand feet deep. All this in pre-glacial times.

Later on the glaciers of several successive epochs greatly widened the valley, and measurably deepened it, making it U-shaped. The cascades then became waterfalls.

But none will see the Yosemite Valley and its cavernous tributary canyons without sympathizing a little with the early geologists. It is difficult to imagine a gash so tremendous cut into solid granite by anything short of force. One can think of it gouged by massive glaciers, but to imagine it cut by water is at first inconceivable.

To comprehend it we must first consider two geological facts. The first is that no dawdling modern Merced cut this chasm, but a torrent considerably bigger; and that this roaring river swept at tremendous speed down a sharply tilted bed, which it gouged deeper and deeper by friction of the enormous masses of sand and granite fragments which it carried down from the High Sierra. The second geological fact is that the Merced and Tenaya torrents sand-papered the deepening beds of these canyons day and night for several million years; which, when we remember the mile-deep canyons which the Colorado River and its confluents cut through a thousand or more miles of Utah and Arizona, is not beyond human credence, if not conception.

But, objects the sceptical, the Merced couldn't keep always tilted; in time it would cut down to a level and slow up; then the sand and gravel it was carrying would settle, and the stream stop its digging. Again, if the stream-cut valley theory is correct, why isn't every Sierra canyon a Yosemite?

Let us look for the answer in the Sierra's history.

The present Sierra Nevada is not the first mountain chain upon its site. The granite which underlay the folds of the first Sierra are still disclosed in the walls of the Yosemite Valley. The granites which underlay the second and modern Sierra are seen in the towering heights of the crest.

Once these mountains overran a large part of our present far west. They formed a level and very broad and high plateau; or, more accurately, they tended to form such a plateau, but never quite succeeded, because its central section kept caving and sinking in some of its parts as fast as it lifted in others. Finally, in the course, perhaps, of some millions of years, the entire central section settled several thousand feet lower than its eastern and western edges; these edges it left standing steep and high. This sunken part is the Great Basin of to-day. The remaining eastern edge is the Wasatch Mountains; the remaining western edge is the Sierra. That is why the Sierra's eastern front rises so precipitously from the deserts of the Great Basin, while its western side slopes gradually toward the Pacific.

But other crust changes accompanied the sinking of the Great Basin. The principal one was the rise, in a series of upward movements, of the remaining crest of the Sierra. These movements may have corresponded with the sinkings of the Great Basin; both were due to tremendous internal readjustments. And of course, whenever the Sierra crest lifted, it tilted more sharply the whole granite block of which it was the eastern edge. These successive tiltings are what kept the Merced and Tenaya channels always so steeply inclined that, for millions of years, the streams remained torrents swift enough to keep on sandpapering their beds.

The first of these tiltings occurred in that far age which geologists call the Cretaceous. It was inconsiderable, but enough to hasten the speed of the streams and establish general outlines for all time. About the middle of the Tertiary Period volcanic eruptions changed all things. Nearly all the valleys except the Yosemite became filled with lava. Even the crest of the range was buried a thousand feet in one place. This was followed by a rise of the Sierra Crest a couple of thousand feet, and of course a much sharper tilting of the western slopes. The Merced and Tenaya Rivers must have rushed very fast indeed during the many thousand years that followed.

The most conservative estimate of the duration of the Tertiary Period is four or five million years, and until its close volcanic eruptions continued to fill valleys with lava, and the Great Basin kept settling, and the crest of the Sierra went on rising; and with each lifting of the crest, the tilt of the rivers sharpened and the speed of the torrents hastened. The canyon deepened during this time from seven hundred to a thousand feet. The Yosemite was then a mountain valley whose sloping sides were crossed by cascades.

Then, about the beginning of the Quaternary Period, came the biggest convulsion of all. The crest of the Sierra was hoisted, according to Matthes's calculations, as much as eight thousand feet higher in this one series of movements, and the whole Sierra block was again tilted, this time, of course, enormously.

For thousands of centuries following, the torrents from Lyell's and McClure's melting snows must have descended at a speed which tore boulders from their anchorages, ground rocks into sand, and savagely scraped and scooped the river beds. Armed with sharp hard-cutting tools ripped from the granite cirques of Sierra's crest, these mad rivers must have scratched and hewn deep and fast. And because certain valleys, including the Yosemite, were never filled with lava like the rest, these grew ever deeper with the centuries.