Volcanic outpourings have ended the life of many extensive Yellowstone
forests. In Amethyst Mountain are twelve forests, one above the other,
buried at different periods by volcanic eruptions. On top of this
mountain the pines and spruces are merrily growing, unmindful of the
buried past--of the tragic tree history beneath. Nature forgets. Ages
ago, the lowest of these entombed forests grew on the mountain plateau
in the sunlight. But a flow of volcanic mud and heavy showers of ashes
overwhelmed and buried it, with the trees standing erect.
This volcanic material added a layer to the plateau. In the new
surface above the buried and forgotten forest, another tree growth
flourished and towered. But the volcanoes only slept. Again their fire
and ashes filled the sky, and again the forest was overwhelmed. Thus
through the ages--through "a million years and a day"--each time the
volcanoes slept the pines peeped up, and again their shadows fell upon
the desolate lava landscape.
At last, twelve or more forests were buried, each as it had stood upon
the mountain, and in a layer by itself. The material in these numerous
fateful volcanic outpourings raised the summit two thousand feet.
It may be that the topmost of these petrified forests was overwhelmed
by the Ice King, but a volcano entombed the others. All were
petrified, fossilized, or opalized. During the ages that went by, the
Lamar River and other factors eroded a wide valley and excavated the
edges of these forest ruins.
[Illustration: PETRIFIED FORESTS IN AMETHYST MOUNTAIN
YELLOWSTONE NATIONAL PARK]
This reveals one of the most appealing geological stories ever
uncovered--twelve illustrated but unwritten chapters of
world-building.
The strata of these twelve forests, story above story, show their
edges in the precipitous northern face of Amethyst Mountain. Thousands
of logs and stumps still partly buried jut and bristle.
Apparently there is an enormous area of these buried fossil forests in
the northeast part of the Park, and perhaps numerous areas elsewhere
in the region. They are also known to exist near the northwest
boundary of the Park.
Mineralized water circulated through and gradually fossilized the
buried trees, changing many to opal. In due time the mud and ashes
that buried these trees also turned to stone. Limbs and tops of trees
were broken off by the ashes, cinders, and mud that buried each
forest. Many tree-trunks were overthrown, but great numbers were
entombed as they stood. They are from one to ten feet in diameter, and
some were of great height. Many of the remaining stumps project forty
feet.
Much of the opalized wood is very beautiful. The change brightened and
intensified the former texture of the wood. In most of these stone
trees and logs the annual rings show clearly. They distinctly reveal
the age of the tree and its rapidity of growth. In many cases the
species is readily determined. Strange stories are told by the fallen
logs, in many of which old worm-holes show. The half-decayed logs were
preserved in their original form, and in the process of fossilization
their hollow interiors were filled with beautiful rosettes and
crystals.
Each of the buried forests contained some trees of different species
from those in the forest just beneath it. Altogether, more than eighty
kinds have been recognized. Many of these would grow only in a mild or
subtropical clime, so the former climate of this region must have been
warmer than at present. Among the trees were redwood, cottonwood,
walnut, pine, oak, sycamore, fig, magnolia, and dogwood.
Ancient Troy was nine ruined cities deep. But here in a national
playground of our own country are twelve tree cities in ruins, one
above another, and topped with a city of living trees. Like the
excavated ruins of Pompeii, these ruined forests set one's mind to
exploring the realm of imagination. Here in a subtropical clime,
possibly a million years ago, was a luxuriant forest. Beneath was a
crowded undergrowth of plants, of shrubbery and waving ferns. Gay
butterflies may have flitted here in the golden sunshine. Trees
enjoyed the storms and lifted their heads serenely into the light.
Then came the tragic end. Twelve times or more was this impressive
drama reënacted.
Trees, like men, often rear their structures upon the ruins of those
that have gone before. This is an old, old world. In the words of
Omar,--
"When You and I behind the Veil are past,
Oh, but the long, long while the World shall last."
Is the volcanic curtain once more to fall upon the forests of this
magic scene?
In "Our National Parks" John Muir comments eloquently upon the fossil
forests and the telling background of most Yellowstone landscapes. He
says:--
Yonder is Amethyst Mountain, and other mountains hardly less rich
in old forests, which now seem to spring up again in their glory;
and you see the storms that buried them--the ashes and torrents
laden with boulders and mud, the centuries of sunshine, and the
dark, lurid nights. You see again the vast floods of lava, red-hot
and white-hot, pouring out from gigantic geysers, usurping the
basins of lakes and streams, absorbing or driving away their
hissing, screaming waters, flowing around hills and ridges,
submerging every subordinate feature. Then you see the snow and
glaciers taking possession of the land, making new landscapes. How
admirable it is that, after passing through so many vicissitudes
of frost and fire and flood, the physiognomy and even the
complexion of the landscape should still be so divinely fine!