Geology of Bryce Canyon National Park[1]

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Bryce Canyon

NATIONAL PARK · _Utah_

[Illustration: DEPARTMENT OF THE INTERIOR · March 3, 1849]

UNITED STATES DEPARTMENT OF THE INTERIOR

Oscar L. Chapman, _Secretary_

NATIONAL PARK SERVICE

Conrad L. Wirth, _Director_

_Contents_

Panorama of Bryce Canyon _Cover_

Geology of Bryce Canyon National Park 4

How to Reach the Park 8

Roads and Trails 8

Administration 10

Naturalist Services 10

Museum 10

Free Public Campgrounds 10

Accommodations 10

Transportation 12

Saddle Horses 12

Post Office and Communication Service 13

Miscellaneous Services 13

Cedar Breaks National Monument 15

_Historic Events_

1866 Capt. James Andrus in command of a military expedition from

St. George, Utah, crossed the Paria River a few miles south

of Bryce Canyon.

1872 A. H. Thompson, geographer of the Powell Survey, sketched

the topography of the Pink Cliffs eastward to Rainbow Point

and ascended Table Cliffs. Lt. W. L. Marshall, topographer,

and G. K. Gilbert and E. E. Howell of the Wheeler Survey

mapped, described, and illustrated for the first time the

features of the park north of Campbell Canyon.

1874-76 Scattered settlements established in the Upper Paria

Valley. Ebenezer Bryce, for whom the park is named, ranged

cattle in the area. The region that includes Bryce Canyon

National Park studied by Capt. C. E. Dutton. View from

Sunset Point described (1876) by T. C. Bailey, Deputy U. S.

Surveyor.

1877 Cannonville and Henrieville founded.

1905 The Paunsaugunt Plateau, which includes the park, set aside

as Powell National Forest.

1923 Bryce Canyon National Monument established by Presidential

proclamation.

1924 Act of Congress authorized the establishment of Utah

National Park, subject to extinguishment of private land

titles.

1928 Name changed from Utah National Park to Bryce Canyon

National Park; park established.

[Illustration: Decorated Capital]

Bryce Canyon National Park includes some of the most interesting

exposures of the Pink Cliffs formation, whose rocks are among the most

colorful of any forming the earth's crust. The major beauty spots of the

area are found where forces of erosion have cut back into the plateau,

forming amphitheaters or wide canyons filled with pinnacles and

grotesque forms.

Most of the park area, with some 30 miles of Pink Cliffs, can be seen

from Rainbow Point, at the southern end of the park. Included in this

panorama are such beautiful amphitheaters as Black Birch Canyon, Agua

Canyon, and Willis Creek. In addition, there are magnificent views

across "the land of the purple sage" to Navajo Mountain, 80 miles to the

east, and to the Kaibab Plateau and the Trumbull Mountains to the south,

the latter 99 miles distant.

In reality Bryce is not a canyon; rather it is a great horseshoe-shaped

bowl or amphitheater cut by water erosion into the Paunsaugunt Plateau

and extending down a thousand feet through its pink and white marly

limestone. The character of the area is well indicated by the Paiute

Indian name, "Unka-timpe-wa-wince-pock-ich," which is translated as,

"red rocks standing like men in a bowl-shaped canyon." The largest

amphitheater is 3 miles long and about 2 miles wide, and is filled with

myriads of fantastic figures cut by weathering influences. Its domes,

spires, and temples are decorated in all the colors of the spectrum.

The area was reserved as Bryce Canyon National Monument by Presidential

proclamation, June 8, 1923. The act of June 7, 1924, authorized its

establishment as Utah National Park when certain conditions regarding

land acquisition had been met. The act of February 25, 1928, changed the

name from Utah National Park to Bryce Canyon National Park and

materially increased the size of the area. On September 15, 1928, when

all alienated lands within the proposed park area were transferred to

the United States, in accordance with the act of June 7, 1924, Bryce

Canyon National Park was established. The park now embraces more than

36,000 acres under Federal ownership.

Bryce Canyon National Park is one of the areas of the National Park

System owned by the people of the United States and administered for

them by the National Park Service, Department of the Interior. In these

areas the scenery and the objects of historic, prehistoric, and

scientific interest are carefully preserved and displayed for public

enjoyment.

Geology of Bryce Canyon National Park[1]

_Regional Features._--In Zion and Bryce Canyon National Parks the type

of scenery peculiar to the plateaus of southern Utah and northern

Arizona attains its most complete expression. Layer upon layer of shales

and sandstones have been carved into architectural forms, astonishingly

alike for size and color. The long stretches of even skyline seen on

approaching the parks from Cedar City (west), Panguitch (north), and

Grand Canyon (south) give an impression of extensive flat surfaces that

terminate in lines of cliffs, but viewpoints within the parks reveal a

ruggedness possessed by few other regions. The canyons are so narrow, so

deep, and so thickly interlaced, and the edges of the strata so

continuously exposed that the region seems made up of gorges, cliffs,

and mesas intimately associated with a marvelous variety of minor

erosion forms. The parks might be considered as mountainous regions in

which departures of many thousand feet from a general surface are

downward rather than upward.

The canyons and adjoining terraces are spectacular illustrations of

erosion. They show with diagrammatic clearness the work of running

water, rain, frost, and wind, of ground water and chemical agencies

active throughout a long period of time. The horizontal tables and

benches, broken by vertical lines that in distant view appear to

dominate the landscape, are normal features of erosion of plateau lands

in an arid climate. The tabular forms are the edges and surfaces of hard

strata from which softer layers have been stripped. The vertical lines

mark the position of fractures (joints)--lines of weakness which erosion

enlarges into grooves and miniature canyons. As they entrench themselves

in horizontal layers of rock that vary in resistance to erosion, the

master streams and their tributaries are developing stairlike profiles

on their enclosing walls. Cliffs in resistant rocks and slopes in weak

rock constitute risers and treads that vary in steepness and height with

the thickness of the strata involved. Thus near the south entrance to

Zion Park the edge of a layer of hard conglomerate is a vertical cliff,

its top a platform. Above this platform a long slope of shale, broken by

many benches developed in hard beds, extends upward to the great cliff

faces of West Temple and the Watchman. In front of Zion Lodge a slope of

weak shales leads upward to a cliff of resistant sandstone above which a

slope of shale extends to the vertical wall of Lady Mountain. In Bryce

Canyon the rim road is on the highest tread of a giant rock stairway

that, as viewed from Rainbow Point, leads downward in steps 30 to 400

feet high to the flat lands 3,000 feet below.

[Illustration: _View of multicolored formations from Bryce Point_

(_Union Pacific Railroad photo_)]

The streams at work in the parks, though relatively small, have steep

gradients, including rapids and waterfalls, and are supplied with

disintegrated rock material swept from the ledges by torrential rains

about as fast as formed. They are therefore powerful agents of erosion,

especially in times of flood. The fresh, sharp, angular profile of

mesas, ridges, and canyon walls and the extensive areas of bare rock are

maintained by the rapid down-cutting and prompt removal of rock waste.

The resulting land forms reflect the aridity and the topographic youth

of southern Utah and contrast strongly with the rounded hills, broad

valleys, plant-covered slopes, and deep soils of more humid regions.

_Geologic History._--A large part of geologic history is revealed in the

canyon walls of Zion and Bryce Canyon National Parks. Just as Grand

Canyon is the best known record of ancient geologic history, Zion Canyon

records most clearly the events of medieval geological time, and Bryce

reveals much of modern geologic history. The story of Zion begins where

that of Grand Canyon ends, and ends where Bryce begins. The rocks

exposed in these three national parks incorporate the records of a

billion years.

[Illustration: _Generalized section of sediments in Zion and Bryce

Canyons_]

Bryce Canyon National Park, Utah (1952) · 第 1 / 16 题