Yosemite

[Music] so [Music] um so [Music] nature on a vast and beautiful scale can be seen in yosemite one of america's most famous national parks gigantic valleys and cliffs shining waterfalls and dark forests old visitors spellbound [Music] they come from all parts of the nation to visit this great park which lies 200 miles east of san francisco on the western slope of the sierra nevada here the visitor can relax amid the quiet grandeur of yosemite and absorb the ever beautiful moons of an ever-changing landscape [Music] [Music] within the boundaries of the park lie the high sierra dominating the scene from every angle their magnificent beauty and the abundant wildlife seem to have been here forever [Music] here in quiet grandeur stand the largest oldest living things on earth the giant sequoia the wawona tree still living has a 26 foot long tunnel caught in 1881. [Music] in 1919 a sequoia fell in this forest a section was cut from the trunk it measured 42 feet around its base some older trees have grown to over 100 feet in circumference tree rings easily seen in this cross section tell the experts many things when there were long periods of drought and how old the tree is each ring indicates one year's growth this tree has lived through some important years in the history of western civilization in 925 a.d in the middle of the dark ages it began growing it saw the year 1066 the year of the battle of hastings and 12 15 the year the magna carta was signed and 1492 the year of the discovery of america and 1620 the year of the landing of the pilgrims 1776 the year of the declaration of independence 1860 the year the civil war began as the slow seasons change the park appears to be a peaceful place the rare snow plant comes to life pushing its stem of crimson blossoms up through a pine needle bed along the banks of the merced river the beautiful dogwood blooms [Music] yosemite's meadows are filled with color the park is a haven of peace a place to escape from the hurried bustling life of the cities [Music] from this high point on the valley's rim visitors can view the whole seven mile long valley yosemite's most spectacular attraction cloud touching el capitan one of the world's largest rocks rises nearly a mile into the sky half dome is easily seen from here this lookout point is more than 3 000 feet above the valley floor [Music] distant yosemite falls can be easily seen as it crashes a half mile into the valley the barren rock face of half dome typifies the rugged granite of yosemite [Music] [Applause] to the east the snowy high sierra rise 12 and 13 000 feet to jagged peaks seen at thundering nevada falls the merced river plunges from a step in its canyon floor nearly 600 feet high burying patterns in the falling water never fail to fascinate the onlooker [Music] [Music] this beautiful cataract rushes down in a white foaming path a path broken only by the rainbow of late afternoon [Music] what great forces of nature produce this magnificent beauty and rugged country the pages of this valley's geologic history show the steps of its development billions of years ago the yosemite area was a warm swampy lowland thickly covered with vegetation some years later the ancient sierra nevada was uplifted and tilted to the west streams like the merced river began cutting down from the heights of the western slope it was the constant cutting of the river through the years and later the relentless grinding of glaciers that carved the yosemite of today in this early stage the sierra nevada was a mountain range of only moderate height river was then a slow flowing stream through the years it dug into the earth slowly carving out a wide frog valley from its meandering course there were no towering cliff walls no bare granite domes no waterfalls in the broad valley landscape yosemite valley was rimmed by low forest covered hills [Music] [Applause] el capitan was one of those hills it looked like this half dome only 1500 feet above the valley floor then was round as shown here north dome and glacier point were only sloping hills side streams flowed down the valley slope without waterfalls or cascades joining the river with scarcely a ripple for millions of years the tireless river cut into the earth meandering in ever-wider curves to form a low broad valley constant carving of yosemite valley by the river now entered a second stage the mountain valley stage this model shows what happened violent earthquakes rocked nearby regions great cracks opened up in the north and east spilling out rivers of fiery lava [Music] for centuries these tremendous mountain building movements continued in several million years the sierra nevada was uplifted to about 7 000 feet [Music] as a result its western slope grew much steeper and the streams became raging torrents [Music] the river gradually cut a new inner valley within its older one eventually it deepened yosemite valley 700 feet the valley looking like this many of the old features were still there but they were much higher above the river gradually the climate turned colder in time forests of hardwood and sequoia covered the area the river with its greatly steepened slope dug out a valley much faster than its tributary streams [Music] the waters from these side streams cascaded down to the river from their high hanging valleys down into the river rushed this powerful plunging water bringing to the river sand and gravel to help grind a deeper path in the valley floor [Music] finally the cutting of yosemite valley entered a third stage the canyon stage as in this model tremendous upheavals far greater than before split the earth's crust [Music] these mountain building movements continued for hundreds of centuries until they pushed the sierra nevada up from about seven thousand feet to their present height of over thirteen thousand feet [Music] now the river raced down an even steeper slope its current was increased to torrential speed pounding the riverbed with sand and gravel carving a deep narrow channel [Music] in time a new v-shaped inner gorge 1500 feet deep was cut within the two older valleys thus the river had dug a canyon three thousand feet deep within the ancient shallow valley of yosemite half dome was now much higher above the river so was el capitan although recognizable they were still far from their present state again the river dug out a valley much faster than its tributary streams again these waters cascaded down to the river from their high hanging valleys only this time their waters tumbled from even greater heights [Music] the climate grew colder each winter became more severe until finally more snow fell than could possibly melt during the summer the first ice age was coming to the sierra nevada gradually the range became almost buried in snow and ice great fields of solid snow grew into huge glaciers down from the sierra moved these massive grinding ice sheets down from every mountain slope a glacier descended through what is now the merced river canyon another great glacier came down tanaya canyon to meet near half dome in a solid river of ice almost a mile thick half dome was completely surrounded by the glaciers glacier point was buried 700 feet down into yosemite valley the glacier moved nearly covering el capitan ice filled the valley nearly to its brim the tremendous crushing power of the glaciers finally ground a broad u-shaped trough out of the old v-shaped profile of the merced canyon this greatly widened and deepened yosemite producing a flat canyon floor and nearly vertical cliff walls [Music] yosemite valley was invaded at least three times by glaciers each time the climate grew mild again the glacier would melt and recede dropping its load of boulders gravel and mud in front of it when the final glacier melted it left such a huge pile of rock material that a dam was formed across the canyon floor [Music] as the ice age came to an end and the climate grew steadily warmer the enormous volume of water produced by the slowly melting glacier was trapped behind this dam a beautiful five and a half mile lake was created ancient lake yosemite in time the stream from the shrinking glacier brought enough silt sand and gravel down into lake yosemite to fill it producing a new flat valley floor that remains today and that's the story of today's yosemite with its broad u-shaped valley and vertical walls it's a product of nature's tireless erosion rivers glaciers rain snow and ice [Music] el capitan and half dome still tower above the valley as if guarding nature's awe-inspiring display of forest rock and water [Music] [Applause] [Music] now after millions of eventful years the merced river flows gently through the valley its peaceful surface telling little of its turbulent and violent past the majestic beauty of yosemite mirrored in its many waters remains and will remain to give joy and inspiration to americans of today and tomorrow [Music] you