STRANGE ROCK FORMATIONS--NATURAL BRIDGES
Almost any unusual form in nature is apt to attract the eye and interest
the beholder; and when such natural objects resemble artificial ones or
bear a fanciful resemblance to animals the similarity intensifies the
interest and almost always leads one to apply fanciful names to them. In
wandering along a rocky shore one instinctively searches for the curious
formations carved out by the unceasing action of the waves; and in
journeying through rugged sections of mountain country each unusual rock
formation rivets the attention at once.
Caves especially have a peculiar attraction of awe and curiosity
combined. Such natural objects as Mammoth Cave in Kentucky, Luray Cave
in Virginia, Calaveras Cave in California, the Garden of the Gods in
Colorado, the Giant's Causeway on the north coast of Ireland, and
Fingal's Cave on the island of Staffa are visited annually by many
thousands of people. And no wonder that all mankind, from the savage to
the most civilized, is charmed with natural arches spanning great
chasms. No cyclopaedia of natural wonders fails to give at least a brief
description of the Natural Bridge of Virginia which spans a small stream
that flows into the James River. So great a wonder was the structure
regarded to be even in colonial times that it then claimed marked
attention. Thomas Jefferson became so much interested in this natural
wonder that he applied to George III for a reservation of land that
should include the bridge, and in 1774 his request was granted. To
accommodate distinguished strangers who might visit the bridge,
Jefferson built near by a log cabin of two rooms. Concerning it he said:
"The bridge will draw the attention of the world."
[Illustration: The Devil's Slide, Weber Canyon, Utah]
Chief-Justice Marshall described it as "God's greatest miracle in
stone." And Henry Clay said it was "the bridge not made with hands, that
spans a river, carries a highway, and makes two mountains one." On the
rocky abutments are found carved the names of many persons. Among them
is that of Washington. In his youth, laboriously cutting places for his
hands and feet, he climbed up the face of one of the steep abutments and
cut his name above all others, where for seventy years it stood
unsurpassed in height. In 1818 a daring college student climbed from the
foot to the top of the rock, thus outranking all others.
The Natural Bridge is composed of blue limestone; it is two hundred and
fifteen feet high, ninety feet wide, and spans a chasm eighty-five feet
across. A public highway lined with trees passes over the top. The
bridge itself is all that remains of the roof of what once was a
limestone cavern.
The southeastern part of Utah is overlaid with strata of red and yellow
sandstone hundreds of feet deep. Ages ago this whole region was elevated
and thereby was distorted by the internal forces which pushed it upward.
Subsequently wonderful transformations were wrought. The flowing streams
gradually bored through portions of the soft, uplifted sandstone,
forming arches and digging deep canyons, while the air and rain rounded
off the rugged parts into graceful shapes.
Wonderful as is the famous Natural Bridge of Virginia, the natural
bridges of Utah are still more wonderful. In White Canyon of
southeastern Utah are Edwin, Carolyn, and Augusta Bridges--magnificent
structures of pink sandstone carved in lines of classic symmetry and
possessing gigantic proportions. At least half a dozen natural bridges
in Utah surpass that of Virginia, not only in beauty and grandeur, but
also in dimensions. They were discovered by cattlemen in 1895, but they
did not become known to the outside world until 1909, when the region
was explored by the Utah Archaeological Expedition.
[Illustration: Witch Rocks, near Echo Canyon, Utah]
Of these bridges the Edwin easily ranks first in graceful symmetry; its
span is one hundred and ninety-four feet, its elevation one hundred and
eight feet, its width thirty-five feet. Combining grace and massiveness,
the Augusta stands pre-eminent. It rises in majestic proportions to the
height of two hundred and twenty-two feet and has a span between
abutments of two hundred and sixteen feet. The width of the road-bed is
twenty-eight feet and the thickness of the arch at the keystone is
forty-five feet. The height of the Carolyn Bridge is two hundred and
five feet and the span one hundred and eighty-six feet.
All these bridges span canyons whose depths correspond to the height of
the arched structures. In White Canyon, a few miles below Edwin Bridge,
under its overhanging rock walls, are the ruins of numerous
cliff-dwellings.
The largest natural bridge in the world yet discovered is the
Nonnezoshi. It is in Nonnezoshiboko Canyon, Utah, not far from the place
where the San Juan River enters the Colorado. This mammoth arch is more
of a flying buttress spanning the canyon than a real bridge. Its height
is three hundred and eight feet and its span two hundred and eighty-five
feet.
To visit these bridges from the nearest railway station requires stage
and horseback riding for upward of one hundred and twenty-five miles.
The latter part of the journey is made over a faint trail through a
rugged country; but the scenery amply repays one for the hardships
endured.
The climatic changes during the ages have been such that this region is
now almost inaccessible on account of the lack of water, except in the
early spring when melting snows yield a temporary supply. Even the
cattlemen pasturing their herds in that section keep them there but a
few weeks during the year, so scarce is both water and vegetation.
In the main, natural bridges are the result of one or another of several
causes. A limestone cavern may be partly destroyed by streams of water,
leaving a portion of the cavern with its roof still in place; the part
of the roof thus remaining becomes the arch of the bridge. A branch of
the Southern Railway threads a natural tunnel near Anniston, Ala., and
the tunnel is the remnant of an old limestone cavern.
In other cases a natural bridge is formed when bowlders, or a mass of
rock, tumbling into a deep crevice is wedged and held in place. In still
other instances a layer of hard or slowly weathering rock may rest upon
a layer of rock which weathers rapidly. In such cases, if the rock
layers form the face of a cliff, natural bridges, caverns, and overhangs
are apt to result.