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Title: The Geologic Story of Colorado National Monument - Revised Edition
Author: Lohman, S. W.
Language: English
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[Illustration: Geology of Colorado National Monument]
[Illustration: BALANCED ROCK, near head of Fruita Canyon. Spire and
rock are Wingate Sandstone resting on red Chinle Formation; thin
caprock is protective layer of resistant Kayenta Formation.
(Frontispiece)]
[Illustration: The Geologic Story of COLORADO NATIONAL MONUMENT]
_The Geologic Story of_
COLORADO
NATIONAL MONUMENT
By S. W. Lohman
GEOLOGICAL SURVEY BULLETIN 1508
UNITED STATES DEPARTMENT OF THE INTERIOR
JAMES G. WATT, _Secretary_
GEOLOGICAL SURVEY
Doyle G. Frederick, _Acting Director_
[Illustration: U.S. DEPARTMENT OF THE INTERIOR · MARCH 3, 1849]
Library of Congress Cataloging in Publication Data
Lohman, Stanley William, 1907-
The geologic story of Colorado National Monument.
(Geological Survey Bulletin 1508)
Bibliography: p. 131
Includes index.
1. Geology—Colorado National Monument.
2. Colorado National Monument.
I. Title. II. Series: United States Geological Survey Bulletin 1508
QE75.B9 no. 1508 [QE92.C6] 557.3s [557.88′17]
80-607952
For sale by the Superintendent of Documents, U.S. Government Printing
Office
Washington, D.C. 20402
Contents
Page
Preface XI
History of the Monument 1
Early history of the region 5
Prehistoric people 5
Late arrivals 10
Early settlement 10
The Brown-Stanton river expedition 11
Kodel’s gold mine 12
Recent cave dweller 13
Artesian wells 14
Geographic setting 16
The geologic story begins 17
Ancient rocks and events 24
A great gap in the rock record 26
The age of reptiles 27
Early landscape 28
Ancient sand dunes 29
The rains came 32
Another gap in the rock record 35
The sea to the west 39
Deposits and events east of the sea 39
Dinosaurs roam the Monument 47
Dinosaurs on the move 53
Yet another gap in the rock record 54
Peat bogs 55
The sea covers the Plateau 56
The sea’s final retreat 56
End of the dinosaurs 60
The age of mammals 61
Early deposits and events 63
Lake Uinta 63
The mountains rise again 64
Nearby lava flows 71
Ancestral Colorado River 72
Piracy on the high plateaus 72
The age of man 76
The ice age 77
Capture of East Creek 78
Canyon cutting 78
A look into the future 83
How to see the Monument 85
Trips through and around the Monument 88
From Grand Junction through the Redlands to the West Entrance
of the Monument 88
From Fruita to the West Entrance of the Monument 96
Through the Monument from West to East Entrances 97
From the East Entrance to Grand Junction 118
Through Glade Park from the northwest arm of Ute Canyon to
Columbus Canyon 119
From Glade Park to Grand Junction via the Little Park Road 121
Résumé of geologic history and relation to other National Parks
and Monuments in the Colorado Plateau 125
Acknowledgments 130
References 131
Additional reading 133
Index 135
Figures
Page
Frontispiece. Balanced Rock II
Figure
1. John Otto 2
2. John Otto’s Monument 4
3. Map of Colorado National Monument 6
4. Petroglyphs 9
5. Cave 14
6. Independence Monument 19
7. Rock Column of Colorado National Monument 20
8. Geologic Map 22
9. Block diagrams of early Proterozoic events 25
10. Petrified sand dunes 30
11. The Coke Ovens 31
12. Red Canyon 33
13. Thin-bedded Kayenta Formation 34
14. Kayenta Formation 36
15. Gap in the rock record 37
16. Entrada Sandstone 41
17. Moab Member of Entrada Sandstone 42
18. Mottled salmon-and-white Slick Rock Member 43
19. White Entrada Sandstone 44
20. Summerville Formation 46
21. Morrison Formation 48
22. Excavating type specimen of _Brachiosaurus altithorax_ Riggs 51
23. Skeletons of typical dinosaurs of Morrison Formation 52
24. Burro Canyon Formation and Dakota Sandstone 54
25. Mount Garfield 57
26. Photo index map 58
27. Common types of rock folds 62
28. Common types of faults 65
29. Ladder Creek monocline and Redlands fault 66
30. Lizard Canyon monocline 67
31. Kodels Canyon fault 68
32. Kodels Canyon fault 69
33. Geologic structures at Fruita entrance to Colorado National
Monument 70
34. Probable drainage patterns and land forms near the Monument at
four successive stages of development 74
35. Fallen Rock 81
36. Unaweep Canyon 82
37. Redlands fault 89
38. Closeup of updragged Wingate Sandstone along Redlands fault 90
39. Bronze plaque and monument marking the discovery of
_Brachiosaurus altithorax_ Riggs 91
40. Reverse part of Redlands fault 92
41. Northwest end of Redlands fault 93
42. Looking west into Monument Canyon 94
43. Looking west from divide on Broadway 2 miles east of West
Entrance to Monument 95
44. New fill on Rim Rock Drive between two tunnels on west side of
Fruita Canyon 98
45. Fruita Canyon 100
46. Campsites at north end of campground 101
47. Picnic area and parking lot 102
48. Window Rock 103
49. Pipe Organ 104
50. Visitor Center and the Saddlehorn 106
51. Independence Monument 107
52. Ute Canyon 110
53. Cold Shivers Point 112
54. Top of old Serpents Trail 113
55. Looking northeast from old Serpents Trail 114
56. South portal of tunnel through Wingate Sandstone 115
57. Devils Kitchen 117
58. Glade Park fault viewed from the ground 122
59. Glade Park fault viewed from the air 123
60. Ladder Creek monocline and Redlands fault 124
61. Geologic time spiral 126
Preface
From 1946 until about 1956 I carried out fieldwork intermittently on the
geology and artesian water supply of the Grand Junction area, Colorado,
the results of which have been published.[1] The area mapped
geologically contains about 332 square miles in the west-central part of
Mesa County and includes all of Colorado National Monument. During the
fieldwork several successive custodians or superintendents and several
park naturalists urged that upon completion of my professional paper I
prepare a brief account of the geology of the Monument in terms
understandable by laymen, and which could be sold at the Visitor Center.
This I was happy to do and there resulted “The geologic story of
Colorado National Monument,”[2] published by the Colorado and Black
Canyon Natural History Association in cooperation with the National Park
Service. This report contained colored sketches by John R. Stacy and a
colored cover, but the photographs and many of the drawings were
reproduced in black and white.
Later, after I had prepared popular style reports containing mostly
color photographs on Canyonlands[3] and Arches[4] National Parks,
officials of Colorado National Monument and I discussed the possibility
of preparing a revised and enlarged edition of my 1965 report containing
mainly color photographs, inasmuch as the supply of the black and white
edition was nearing exhaustion, and later became out of print. At the
meeting in the Monument on June 8, 1976, attended by Robert (Bob) E.
Benton, Superintendent, A. J. (Jerry) Banta, Supervising Park Ranger,
Margaret Short, Park Naturalist and Secretary of the Natural History
Association, and me, it was agreed that: (1) A revised and enlarged
edition containing mostly color photographs should be prepared for
publication as a bulletin of the U.S. Geological Survey, and (2) that
the Colorado and Black Canyon Natural History Association gave its
permission for use of any or all of the copyrighted material in the
first edition. The present report resulted.
The cover is a duotone of a 9- × 12-cm infrared photograph of
Independence Monument taken by me. (See also fig. 6.) Most of the color
photographs were taken by me on 4- × 5-inch or 9- × 12-cm tripod mounted
cameras using lenses of several focal lengths, but I took some with
35-mm cameras. Some of the color photographs and all the black and white
ones were taken by those credited in the captions, to whom grateful
acknowledgment is made. The points from which most of the photographs
were taken are shown in figure 26.
[Illustration: West side of Otto’s Monument
ROCK OF AGES
CROSS OF AGES]
History of the Monument
The story of how Colorado National Monument came into being is as
colorful as the canyons and cliffs themselves. The fantastic canyon
country had a magical attraction for John Otto[5] (fig. 1) who, in 1906,
camped near the northeastern mouth of Monument Canyon and began building
trails into the canyons and onto the mesas—the high tablelands that
separate the deep canyons. He did this back-breaking work simply because
he wanted to and so that others could share the beauty of this wild
country.
In 1907 Otto got the Grand Junction Chamber of Commerce to petition
Secretary of the Interior James A. Garfield to set aside the area as a
National Monument. Otto’s dream came true on May 24, 1911, when
President William Howard Taft signed the proclamation creating the
Monument. On June 14, Otto climbed to the top of Independence Monument
(fig. 6) where he placed the Stars and Stripes to celebrate Flag Day.
For several years thereafter Otto placed the flag atop Independence
Monument on July 4th to celebrate Independence Day.
Until about 1921 the only routes into the Monument proper were John
Otto’s trails, but in that year the ranchers of Glade Park joined with
Otto in building the steep, twisting Serpents Trail from No Thoroughfare
Canyon to the mesa above—a much shorter route to Grand Junction. It had
54 switchbacks and climbed about 1,500 feet in 2½ miles. The Serpents
Trail was included in the Monument in 1933 and was used until 1950 when
an easier route was built up the west side of No Thoroughfare Canyon and
through a tunnel to the top of the mesa (figs. 3, 56). The Serpents
Trail has been preserved as an interesting foot trail (fig. 55), which
can be hiked downhill in an hour or so. A parking area near the foot of
the trail allows one member of a group to drive ahead to await the
others.
[Illustration: JOHN OTTO, fantastic father of Colorado National
Monument, and his helpers. Photograph courtesy Grand Junction
Chamber of Commerce. (Fig. 1)]
In 1924 John Otto got the idea that the Monument should include a herd
of big game, so he talked the Colorado Game and Fish Department into
shipping six young elk, and he got the local Elks Lodge to pay the
transportation costs. The elk were turned loose in Monument Canyon, but
they found the sparse vegetation and scant water supply ill suited to
their needs, so after a few years they found a way out over the rim and
migrated about 20 miles south of the Monument to lush high country where
they joined with native elk and multiplied to become the ancestors of
the present fine herd on Piñon Mesa (shown in fig. 34_D_). Occasionally
a few return to the Monument and may be seen mainly in Ute Canyon.
Native mule deer are frequently seen in and near the Monument.
Far from being discouraged, Otto then hatched the idea to start a
buffalo[6] herd to be purchased by donations of buffalo nickels from
school children and by contributions from the Odd Fellows and others. He
finally raised enough money to get the patient Game and Fish Department
to send him two cows and one bull. Unfortunately the bull died, so Otto
talked the National Park Service into shipping him a bull from
Yellowstone National Park. This time success crowned his efforts, and
the small herd eventually multiplied to as many as 45 animals, but
generally the herd has been kept at about 20-25 head ever since. You may
spot some of them when you gaze down into Monument or Ute Canyons or
when you drive past the northeastern boundary. Rarely, you may spot one
in Red Canyon.
At the northeast corner of Fourth Street and Ute Avenue in Grand
Junction is a most unusual object, which illustrates yet another
peculiarity of John Otto—fantastic father of Colorado National Monument
(fig. 2). Its history is best told by quoting from Al Look,[7] though
its purpose still remains a mystery.
One day a horse drawn dray backed up to a vacant lot on Grand
Junction’s Main Street [corner 6th] and unloaded a granite cube four
feet square, carved on two sides. It weighed more than a ton and Otto
supervised the setting.
One side [now facing west and not visible in fig. 2] showed a three
foot circle containing a swastika with a five pointed star in each
quarter. Above the emblem was carved “Rock of Ages” and below read
“Cross of Ages.” The second side [now facing south, and shown in fig.
2] was beyond normal comprehension. Two large W’s on either side of a
small swastika were over the letters or initials P.P., then four chain
links with the letters T, H, L, J. inscribed, followed by the initials
I.E. Below on the left was “1918,” over “Year 1”. On the right was
“Old Count” and under it “New Count.” Between them stands the word
‘MARCH.’ Below this are abbreviations for the seven days of the week
with the figure 1 under MON ending with a 6 under SAT. The bottom line
[most of which is barely visible in the photograph] contained the
figure 7 in a circle, a carpenter’s square, a small rectangle,
probably representing a level, a plumb bob, a carpenter’s compass and
a circle showing the western hemisphere. That is all. It made sense to
John Otto because from somewhere he gathered considerable money to
have this monument carved by the local gravestone merchant. It stood
for several years to mystify pedestrians, and was finally moved beside
the Redlands road to the [east entrance of] Colorado Monument where it
is now hidden by weeds.[8]
It was still there in the 50’s when my family and I were startled to
find it. We were afraid it might be lost forever so are glad it finally
found a safe resting place on a concrete slab at the museum. I shall
greatly appreciate hearing from any reader who can decipher this enigma.
[Illustration: JOHN OTTO’S MONUMENT, at southwest corner of the
Historical Museum and Institute of Western Colorado, at northeast
corner of Fourth Street and Ute Avenue, Grand Junction. View looking
north. Face is 4 feet square. (Fig. 2)]
Otto’s rock is at the southwest corner of The Historical Museum and
Institute of Western Colorado. The main attraction inside is a life-size
skeleton of _Allosaurus_ (fig. 23), whose bones are exact plastic
replicas of real ones at the museum of Brigham Young University, at
Provo, Utah. The painstaking casting of the “bones” and assembly of the
self-supporting skeleton was done by Al T. Look, son of author Al Look
listed under “References.” The museum also houses other items of
interest from the Grand Junction area.
Construction of the scenic Rim Rock Drive through the Monument was begun
by the National Park Service about 1931 using workers from the Civilian
Conservation Corps, and the drive eventually was completed to join roads
from Fruita and Grand Junction. The route from Fruita includes a winding
road up Fruita Canyon and through two tunnels to the mesa (figs. 3, 44,
45).
A modern Visitor Center, new housing facilities for park personnel,
additions to the campgrounds, the Devils Kitchen Picnic Area near the
East Entrance, several self-guiding nature trails, and additional
overlooks and roadside exhibits were completed in 1964 as part of the
Mission 66 program of the National Park Service.
The Monument originally included 13,749 acres, but boundary changes in
1933 and 1939 increased the total to 17,660 acres, and the inclusion of
all of No Thoroughfare Canyon and other boundary adjustments in 1978
increased the size to about 20,457 acres, or about 32 square miles (see
map, fig. 3).
Early History of the Region
Prehistoric People
John Otto, early explorers, and even the Ute Indians who once hunted in
the area were by no means the first people to view the Monument, in fact
they were “Johnnies-come-lately.” Considerable evidence indicates that
prehistoric people inhabited the area thousands of years ago.
[Illustration: MAP OF COLORADO NATIONAL MONUMENT, showing location
in Colorado, boundaries, streams, highways and roads, principal
trails, named features, overlooks, and—in triangles—trip guides
localities. The trip guides numbers correspond to the numbers in the
right margins of the section entitled “Trips through and around the
Monument.” Visitors are given pamphlets at the two entrance stations
and may purchase other reports and maps at the Visitor Center. (Fig.
3)]
Many years ago Al Look, of Grand Junction, discovered and excavated two
caves in the part of No Thoroughfare Canyon formerly outside the
Monument. He found stone projectile points, knives, awls, milling
stones, parts of a sandal and coiled basket, reed matting, corn,
corncobs, acorns, and animal bones, but no pottery—indicating that the
people had not progressed beyond basket making. Similar artifacts were
found in several other nearby places on the Uncompahgre Plateau.
Archaeologists have named this old culture the Uncompahgre Complex, and
date it back to a few thousand years before the time of Christ.[9] It
should be pointed out that it is unlawful to remove artifacts, fossils,
rocks, or minerals from a National Park or Monument.
In the summer of 1963 an archaeological survey of Colorado National
Monument was carried out, under the terms of an agreement between the
National Park Service and the University of Colorado, by Stroh and Ewing
and their field assistants.[10] A total of 75 aboriginal sites were
found of which 71 were within the Monument boundaries of that date, and
4 were closely adjacent. These comprised 41 open campsites, 24 rock
shelters, 2 small caves, and 8 chipping stations. Artifacts recovered
included 62 projectile points, 21 metates (grinding stones), 40 manos
(hand stones), 111 whole or fragments of blades or scrapers, 6 choppers,
several fragments of baskets, potsherds (bits of broken pottery) at two
sites, 2 wood awls, several strands of yucca fibers, 3 corncobs, 6
kernels of corn, several bone fragments, storage cists at five sites,
and petroglyphs at three locations.
Stroh and Ewing concluded that the majority of the sites appear to have
been the campsites of a hunting and gathering people, and they
speculated that there may have been aboriginal activity in the area from
as long as several thousand years ago to relatively recent times.
The largest of the petroglyphs,[11] or rock drawings, are on a fallen
slab of Wingate Sandstone in No Thoroughfare Canyon, and are shown in
figure 4. Archaeologist John Crouch (footnote 10), who kindly reexamined
these petroglyphs in February 1980, told me that most of the figures
appear to be Shoshonian (Ute), but that some may be of the Fremont
culture[12] or even older.
[Illustration: PETROGLYPHS, on fallen slab of Wingate Sandstone in
No Thoroughfare Canyon. Figure of man at lower right is about 6
inches high. The fading designs were traced with chalk before
photographing them. Photograph by T. R. Giles, U.S. Geological
Survey. (Fig. 4)]
[Illustration: Petroglyph]
Late Arrivals
Early Settlement[13]
Prior to 1881 the Monument area was inhabited only by Ute Indians, but
it was visited from time to time by a few fur trappers, explorers, and
geologists. In 1776 an expedition led by Fathers Dominguez and Escalante
passed northward across Grand Mesa, the high plateau just east of the
area, which is pointed out in many of the photographs. A trading post
was built by Joseph Roubidoux about 1838 just above the present site of
Grand Junction. In 1853 Captain John W. Gunnison, seeking a new route
for a transcontinental railroad, led an exploring party down what is now
the Gunnison River Valley, past the confluence with the Grand River (now
called the Colorado, p. 16), and on down the valley. Geologists and
topographers of the Hayden Survey found only Ute Indians in the area in
1875 and 1876, and their field season of 1875 was abruptly cut short
because of skirmishes with hostile Utes. After the Meeker (Colorado)
Massacre of 1879, believed by many to have been caused mainly by the
ignorance and shortsightedness of Meeker himself, treaties were signed
forcing the Utes out of western Colorado onto reservations in eastern
Utah, and the last of the Utes was reportedly out of the area by
September 1881. The Grand Valley was immediately opened to settlement,
and the first ranch was staked out on September 7, 1881. Nineteen days
later George A. Crawford founded Grand Junction as a townsite and formed
the Grand Junction Town Company the next month. The success of the new
town was assured on November 21, 1882, when the narrow-gage line of the
Denver and Rio Grande Railroad (now Denver and Rio Grande Western
Railroad) reached it via the Gunnison River valley. The town of Fruita
was founded by William E. Pabor in 1883 and incorporated the following
year.
The Brown-Stanton River Expedition[14]
Of the many early expeditions down the Colorado River, only one went
past what is now Colorado National Monument—the ill-fated Brown-Stanton
expedition. After the pioneering expeditions of 1869 and 1871 down the
Green and Colorado Rivers by Major John Wesley Powell and his men, the
many ensuing river expeditions started in Utah or Wyoming; but the first
phase of the Brown-Stanton expedition started in Colorado—at Grand
Junction. In 1889 Frank M. Brown organized a company for the
construction of the proposed Denver, Colorado Canyon, and Pacific
Railway, which was to carry coal from mines in Colorado over a
“water-level” line through the mighty canyons of the Colorado River to
the Gulf of California some 1,200 miles away, from which coal would be
shipped to various ports in California. On March 26, 1889, president
Brown, chief engineer F. C. Kendricks, and assistant engineer T. P.
Rigney drove the first stake at Grand Junction for a survey of the new
line. Then Brown left for the East to obtain financing, and the other
two men plus some hired hands took off in a boat down the Grand River.
After reaching the confluence, they towed the boat up the Green River to
the town of Green River, Utah, thus becoming the first to make this trip
upstream, albeit on foot and dragging their boats. Brown, who had
returned from the East, his newly appointed chief engineer Robert
Brewster Stanton, and 14 others in six ill-designed boats of cedar
rather than oak, left Green River, Utah, on May 25, 1889. Against the
advice of Major Powell and others, they carried no life preservers.
After many mishaps, Brown and two others were drowned near the head of
Marble Canyon, and the ill-fated expedition temporarily ground to a
halt. However, the indefatigable Stanton had new boats built of oak, and
with a reorganized party of 12 left the mouth of the Dirty Devil River
on November 25. After many additional mishaps the party finally reached
the Gulf of California on April 26, 1890. In spite of Stanton’s heroic
efforts, the railroad was never built, and the Grand Canyon was spared
the huffing and puffing of locomotives.
Kodel’s Gold Mine[15]
As shown in figures 3, 8, and 26, the first major canyon west of the
West Entrance of the monument is called Kodels Canyon (pronounced
\‘kōd^ǝls\). It was named after an early-day stonemason turned
prospector, a hermit, who came to the Fruita area before 1900 and
prospected for gold until at least 1930 in the canyon that now bears his
name. He seemingly built a cabin or house near the mouth of the canyon,
spent most of the rest of his life in a vain quest for gold in the
canyon, barricaded his house against would-be intruders, and took
potshots at anyone approaching his home for fear they were after his
“gold.” Some thought him only half crazy, but when he took repeated
shots at an Indian named Henry Kadig, he was adjudged wholly insane and
sent to the mental hospital at Pueblo, Colorado, for several years. When
he got out he sold the grazing rights in his canyon to the late Irving
Beard of Fruita, and seemingly was not heard from again. According to
various estimates, Kodel dug an adit between 18 and 150 feet into the
dark Proterozoic rock in the side of the canyon (shown in fig. 3), then
sunk a shaft somewhere between 30 and 50 feet deep. He was always “on
the verge of a big strike,” but there is no record of any actual
production.
Later, a prospector from the midwest spent several summers digging in
Devils Canyon, the next major canyon to the west, but he was equally
unsuccessful. The unsuccessful attempts of Kodel and others is not
surprising, for the two canyons are some 100 miles north of the Colorado
mineral belt—a band extending roughly from Boulder to the western part
of the San Juan Mountains, in which ore-bearing Upper Cretaceous or
lower Tertiary rocks were intruded into all overlying rocks of whatever
age.
Recent Cave Dweller
About 3 miles west of the Glade Park Store and Post Office are three
large caves in a cliff of the Wingate Sandstone on the north wall of a
canyon containing a tributary of Clark’s Wash. The middle cave, which
formerly contained a small one-room framehouse and other improvements,
was occupied for about 40 years prior to 1958 by Mrs. Laura Hazel Miller
(fig. 5). A large cave just to the west (left) was used for storage, and
another large cave just to the east formerly was fenced to shelter
domestic animals. Mrs. Miller lived alone most of this time but had a
dog for companionship the last few years she lived in the cave. When my
wife and I visited her in the mid-fifties we had a very pleasant
conversation with this very intelligent woman and could hardly believe
she was 87 years old. She could not understand why anyone could live in
crowded cities as she much preferred the peace and quiet of her cave.
Once a week she walked the 6 miles round trip to and from the Glade Park
Store and Post Office, bought what few necessities she needed, and
telephoned her daughter in Grand Junction. Maybe she had something the
rest of us have missed! She became sick in her nineties and moved to
Grand Junction to live with her daughter. After she died, the property
was sold, and I have since observed that vandals had burned her one room
house and had destroyed most of the other improvements.
[Illustration: CAVE in Wingate Sandstone inhabited by Mrs. Laura
Hazel Miller (visible between gate posts) until 1958. One-room house
was entirely within cave, and smaller storehouses extended back of
the house. Note blackening of cave roof by soot. (Fig. 5)]
Artesian Wells
It may surprise you to learn that several sandstone formations supply
water to artesian wells northeast of the Monument in The Redlands,
Orchard Mesa, and the southwestern side of the Grand Valley, most of
which are 500 to more than 1,000 feet deep. When first drilled and for
some years later these wells flowed at the land surface, but eventually
after too many wells had been drilled too close together, each well
reduced the output of neighboring wells until most wells ceased to flow
naturally. This made it necessary for most well owners to install pumps,
which further aggravated the problem by reducing the artesian head (the
height to which the water rises above the formation from which it
issues). This created a situation not unlike too many children sucking
on straws in the same ice cream soda, and led to a detailed
investigation by the U.S. Geological Survey and the Colorado Water
Conservation Board,[16] outgrowths of which were the present report and
its predecessors.
The water system of the Ute Conservancy District was virtually completed
by late 1964 and began to supply water to rural residents of Grand
Valley between the towns of Palisade and Mack through a vast network of
pipelines. The water is obtained from surface sources on the north flank
of Grand Mesa east of the valley and is brought to the valley via a
pipeline down the valley of Plateau Creek. Use of the new water has
reduced the draft on many of the artesian wells. The reduced draft has
locally arrested the decline in the artesian head or has actually
allowed some recovery in head.
In order of their importance and productivity the water-bearing
sandstones are the Entrada, the Wingate, and local sandstone lenses in
the lower part (Salt Wash Member) of the Morrison Formation (fig. 7). In
a few places small flows or yields are obtained from wells that tap the
Dakota Sandstone and underlying Burro Canyon Formation, but inasmuch as
the Dakota contains some marine sandstones from which all the salt
seemingly has not yet been flushed out, the water from most of these
wells is brackish or salty.
As we will see on the trip “From Grand Junction through The Redlands to
the West Entrance of the Monument,” pages 88-95, in and near the
Monument these sandstones look bone dry, so how can they supply water to
artesian wells? They are indeed dry in all the cliff exposures, but as
will be noted later when the bending and breaking of the rocks are
discussed (p. 64-71), erosion has exposed the upturned sandstones so
that they may take in water from the many small streams that drain the
Monument and adjacent areas for short periods after summer
thundershowers or during spring thaws. The water moves slowly down the
dipping sandstones and becomes trapped under pressure beneath overlying
beds of siltstone or mudstone—materials that are nearly impervious.
Geographic Setting
Geologists and geographers have divided the United States into many
provinces, each of which has distinctive geologic and topographic
characteristics that set it apart from the others. Colorado National
Monument is in the northeastern part of the Canyon Lands section of the
Colorado Plateau Province—a province that contains 15 national parks and
monuments, about 3 times as many as any other province. This province,
hereinafter referred to simply as the Colorado Plateau, or the Plateau,
covers some 150,000 square miles and extends from Rifle, Colo., at the
northeast to a little beyond Flagstaff, Ariz., at the southwest, and
from Cedar City, Utah, at the west nearly to Albuquerque, N. Mex., at
the southeast. This scenic province consists of high plateaus generally
ranging in altitude from 4,500 feet to more than 7,000 feet, which are
deeply and intricately dissected by literally thousands of canyons.
Colorado National Monument is drained entirely by the Colorado River,
which flows to the northwest in the wide Grand Valley just a few miles
from the northeastern border (fig. 3). The small streams that drain the
Monument contain water only after summer thundershowers or after rapid
snowmelt.
Why is the large valley of the Colorado River called the Grand Valley?
The Colorado River northeast from its confluence with the Green River in
the middle of Canyonlands National Park[17] formerly was called the
Grand River, and the Green and Grand joined at the confluence to form
the Colorado River. The Grand River was renamed Colorado River by act of
the Colorado State Legislature approved March 24, 1921, and approved by
act of Congress July 25, 1921. But the old term still remains in names
such as Grand County, Colo., the headwaters region; Grand Valley, a town
16 miles west of Rifle, Colo.; Grand Valley between Palisade and Mack,
Colo.; Grand Mesa, an extensive plateau which towers more than a mile
above the Grand and Gunnison River Valleys; Grand Junction, Colo., a
city appropriately situated at the confluence of the Grand and Gunnison
Rivers; and Grand County, Utah, which the river traverses after entering
Utah.
The Geologic Story Begins
Colorado National Monument is a land of brightly colored cliff-walled
canyons and towering monoliths—a majestic sample of mysterious
canyonlands that stretch hundreds of miles to the west and south. Now a
desert region more than a mile above the sea, it was not always so. More
than a billion years ago the site of the Monument was deep beneath the
sea. Later, lofty mountains were pushed up only to be obliterated
eventually by the slow but relentless forces of erosion. Millions of
years later the earth shook to the stride of 10-ton dinosaurs—then the
sea returned again and sharks swam over the region looking for food.
These are but a few samples of the interesting—even exciting—events in
the long geologic history of the Monument. Many pages, indeed several
whole chapters, of its history are missing and must be inferred from
nearby regions where the story is more complete. Thus, the cliffs and
canyons you are looking at did not get that way overnight. An
understanding of the geologic processes and events that led to the
scenic features of today should help you toward a clearer picture and
greater appreciation of nature’s handiworks (fig. 6).
Geologists recognize rocks of three distinctly different modes of
origin—sedimentary, igneous, and metamorphic, and there are many
variations of each type. The sedimentary rocks of the Monument are
composed of clay, silt, sand, and gravel carried and deposited by moving
water; silt and fine sand transported by wind; and some limestone,
composed mainly of the mineral calcium carbonate, which was precipitated
from water solutions in freshwater lakes. In areas not far to the
northeast and southwest are many sedimentary rocks of marine origin,
that is, materials that were deposited in the ocean or shallow inland
seas, but in the Monument marine sedimentary rocks occur only in parts
of the Dakota Sandstone; however, the overlying marine Mancos Shale
underlies the adjacent Grand Valley and forms the lower slopes of the
Book Cliffs across the valley (fig. 25).
Igneous rocks were solidified from liquid molten rock intruded upward
into any preexisting rocks along cracks, joints, and faults. Molten rock
that reaches the land surface and forms volcanos or lava flows is called
extrusive igneous rock. Joints are cracks or breaks in rocks along which
no movement has taken place. Faults are cracks or joints along which one
side has moved relative to the other. Different types of faults are
shown in figure 28. Metamorphic rocks were formed from either of the
other types by great heat and pressure at extreme depths in the Earth’s
crust. Metamorphic rocks and some intrusive igneous rocks make up the
hard, dark rock that floors all the deep canyons in and near the
Monument. The nearest extrusive igneous rocks are the thick, dark lava
flows that cap towering Grand Mesa to the east and Battlement Mesa to
the northeast.
[Illustration: INDEPENDENCE MONUMENT, separating the two entrances
of Monument Canyon. Looking north from Grand View; Colorado River,
Grand Valley, and Book Cliffs in distance. Roan Cliffs are white
cliffs at extreme distance on right skyline. Dark rock flooring
canyon is Proterozoic metamorphic rock, red material in slope at
base of cliffs is the Chinle Formation, vertical cliffs are Wingate
Sandstone, thin protective caprock on top of cliffs is lower
sandstone of the resistant Kayenta Formation. The top of
Independence Monument is nearly 450 feet above the floor of the
canyon. (Fig. 6)]
[Illustration: ROCK COLUMN OF COLORADO NATIONAL MONUMENT. 1 foot =
0.305 meter. (Fig. 7)]
AGE (millions of years)
GEOLOGIC AGE
NAME OF ROCK FORMATION
KIND OF ROCK AND HOW IT IS SCULPTURED BY EROSION
THICKNESS (feet)
NAMED FOR OCCURRENCE AT OR NEAR
80
Late Cretaceous
Mancos Shale
Gray and black shale, and thin beds of sandstone and limestone.
Contains sea shells. Eroded from Monument, but underlies
Grand Valley and forms lower part of Book Cliffs.
3,800
Mancos, Colo.
Dakota Sandstone
Coaly shale, sandstone, conglomerate, and lignite coal. Contains
plant remains. Forms benches and slopes. Caps highest hill
in Monument.
150
Dakota, Nebr.
115
Early Cretaceous
Burro Canyon Formation
Green siltstone and shale, and sandstone and conglomerate. Forms
benches and slopes. Crops out on highest hill in Monument.
60
Burro Canyon San Miguel Co., Colo.
EROSIONAL UNCONFORMITY
150
Late Jurassic
Morrison Formation
Brightly colored siltstone and mudstone, and sandstone and
limestone. Contains dinosaur bones and fresh-water shells.
Forms slopes and badlands. Lower third with sandstone
lenses is Salt Wash Member, upper two thirds is Brushy
Basin Member.
600
Morrison, Colo.
170
Middle Jurassic
Summerville Formation
Brightly colored siltstone and mudstone, and thin sandstones.
Forms slopes.
54
Summerville Point San Rafael Swell, Utah
Entrada Sandstone
White and salmon-red sandstone. Upper level-bedded Moab Member
forms stair steps, lower mostly cross-bedded Slick Rock
Member forms cliffs.
150
Entrada Point Moab, Utah Slick Rock, Colo.
195
Jurassic and Triassic(?) (missing)
EROSIONAL UNCONFORMITY
210
Late Triassic(?)
Kayenta Formation
Red and purple siltstone and shale, and sandstone and
conglomerate. Forms bench between two cliffs and mesas
between canyons.
45-80
Kayenta, Ariz.
Late Triassic
Wingate Sandstone
Buff and light red sandstone. Cross-bedded and level-bedded.
Forms highest cliffs and most of named rock features in
Monument.
350
Fort Wingate, New Mex.
Chinle Formation
Red siltstone and shale, and some limestone conglomerate. Forms
steep slopes at foot of cliffs.
80-100
Chinle Valley N.E. Ariz.
GREAT UNCONFORMITY
240-1000
Triassic, Paleozoic, Younger Proterozoic (missing)
Unnamed
Schist, gneiss, granite, and pegmatite dikes. Floors main
canyons and forms high bluff above The Redlands.
Unknown
1500
Older Proterozoic
After the materials of the sedimentary rocks were deposited and covered
by younger layers, they generally became saturated or partly saturated
with ground water containing small amounts of dissolved minerals. Some
of these minerals precipitated from solution and cemented the loose
particles into rocks of varying hardness. Thus, most of the sandstones
are partly cemented with the mineral calcite, composed of calcium
carbonate (CaCO₃), but some are cemented also with silica (SiO₂) or
hematite (Fe₂O₃).
Look almost anywhere in the Monument and you will see that the rocks are
piled up in layers of different color, thickness, and hardness—much like
a vast layer cake. In most of the Monument, these layers are flat or
slope gently down to the northeast, but along the northeastern boundary
they are sharply bent or broken as though the cake had been carelessly
placed over the edge of a table and had sagged.
Let us consider these layers one by one, beginning with the oldest at
the bottom, for each is a partial record of events long past. Layers of
rock that can be easily recognized and distinguished from other layers
are called formations and are named after a place where they are well
exposed. For the name to be accepted for general usage it must be the
first published description in a technical report of a particular
sequence of rock layers. The places after which the formations of the
Monument were named are given in the rock column (fig. 7), and the
outcrops of the formations are shown on the geologic map (fig. 8). In
the pages that follow, the geologic events that shaped the Monument we
see today are discussed in chronological order, beginning with the
oldest rocks that floor the deep canyons.
[Illustration: Petroglyph]
[Illustration: GEOLOGIC MAP of Colorado National Monument and
vicinity, simplified and greatly reduced from part of maps at scale
1:31,680 by Lohman (1963, 1965a). For additional surficial deposits
in the Grand Valley and Orchard Mesa see Cashion (1973). (Fig. 8)]
EXPLANATION
QUATERNARY
Qal—ALLUVIUM
Qls—LANDSLIDE DEPOSITS
CRETACEOUS
Km—MANCOS SHALE
Kdb—DAKOTA SANDSTONE AND BURRO CANYON FORMATION, UNDIVIDED
JURASSIC
Jms—MORRISON AND SUMMERVILLE FORMATIONS, UNDIVIDED
Je—ENTRADA SANDSTONE
TRIASSIC
TRk—KAYENTA FORMATION
TRwc—WINGATE SANDSTONE AND CHINLE FORMATION, UNDIVIDED
PROTEROZOIC
PL—SCHIST, GNEISS, GRANITE, AND PEGMATITE
CONTACT FAULT—Dashed where approximately located; dotted where
concealed. U, upthrown side; D, downthrown side
ANTICLINE
SYNCLINE
CENTRAL AXIS OF SYMMETRICAL MONOCLINE—Showing direction of plunge
UPPER BEND OF MONOCLINE—Showing direction of plunge
STRIKE AND DIP OF BEDS
ABANDONED MINE
Geology simplified from Lohman, 1965a
_(Showing location of—)_
DEVILS CANYON MONOCLINE
KODELS CANYON FAULT
LIZARD CANYON MONOCLINE
FRUITA CANYON MONOCLINE
LADDER CREEK FAULT
Ancient Rocks and Events
The dark rocks that floor all the large canyons of the Monument (fig. 6)
and form the high bluffs along the northeastern boundary (figs. 37, 38,
40, 41) are of early Proterozoic[18] age—among the oldest known rocks of
the Earth. Most were once sand and mud that spread out on the bottom of
the sea and later hardened into sedimentary rocks (fig. 9-1). After
thousands of feet of such rocks had accumulated, they were squeezed,
bent, and lifted up by slow but mighty movements of the Earth’s crust to
form high mountains perhaps like the Rockies. Heat and pressure that
developed at great depth in the roots of these mountains changed the
sediments into metamorphic rocks known as schist (finely banded) and
gneiss (coarsely banded) (fig. 9-2). The rocks are about 1½ billion
years old (fig. 7).
Later in Proterozoic time, about a billion years ago, molten material
from below was forced upward along cracks or faults and cooled slowly to
form thin seams or dikes and irregular bodies of granite (fig. 9-3).
Dikes are called pegmatite when they contain large crystals of pink
feldspar, white or clear quartz, black tourmaline, and large flakes of
white mica. Small pegmatite dikes that pass through the older schist and
gneiss may be seen along roadcuts in Fruita and No Thoroughfare Canyons.
[Illustration: BLOCK DIAGRAMS OF EARLY PROTEROZOIC EVENTS (after
Edwin D. McKee). (Fig. 9)]
[Illustration: ① Layers of sand, mud, and other sediment accumulated
in the sea and later were hardened into sedimentary rocks.]
[Illustration: ② The strata were compressed, bent, and uplifted into
high mountains. Heat and pressure at great depth changed the
sediments into banded schist and gneiss.]
[Illustration: ③ Molten rock flowed upward along cracks or faults.
Upon cooling it formed lava at the surface and granite or pegmatite
beneath.]
[Illustration: ④ During eons of time the forces of erosion wore down
the mountains to a nearly level plain.]
A Great Gap in the Rock Record
If you look down into any of the large canyons in the Monument, you will
notice a brick-red formation, the Chinle, which forms steep slopes at
the foot of the high cliffs and lies upon the dark Proterozoic rocks
along nearly straight lines of contact. Such a straight-line contact is
particularly well shown about midway up the high bluffs along the
northeastern boundary of the Monument (fig. 37). If the red layer and
all overlying rocks were stripped away, these straight lines would be
the exposed edges of a remarkably smooth, nearly flat erosion surface on
the top of the dark Proterozoic rocks, as shown in the last diagram of
figure 9. A vast amount of time passed between the carving of this
surface and the deposition of the red Chinle, and no record of the
events during this time is preserved in the Monument.
During the latter part of the Proterozoic Eon and parts of the long
Paleozoic Era that followed, the dark rocks were submerged beneath the
sea several times and received sediments now found in areas to the
northeast and southwest. Beginning in the Pennsylvanian Period some 330
million years ago (fig. 61), a large upfold of the rocks, or anticline
(fig. 27), known to geologists as the Uncompahgre Highland, rose high
above sea level, probably reaching its highest level in Late
Pennsylvanian or Permian time. This old highland formed an imposing
chain of mountains in about the position of the present Uncompahgre
Plateau.
After the old rocks were pushed up into these high mountains what became
of them? From the moment the mountains began to rise, their rocks were
buffeted by wind, pounded by rain, pried open by frost, scoured by
debris-laden streams and, perhaps by glaciers, and the loosened rock
particles were dissolved or carried to the sea. Most rocks are brittle
enough to crack when bent by Earth forces. Such cracks, called joints,
are easy targets for erosion. The freezing of water in joints tends to
pry the rocks apart. The breakup of the rocks was hastened by the
chemical attack on rock minerals by water charged with oxygen and carbon
dioxide. When land plants became established in later geologic eras,
soil acids formed from decaying vegetation also assisted materially in
breaking up the rocks.
These same erosion processes are going on today, but their effects are
scarcely noticeable from year to year except in soft earth after storms
or floods. During eons of time, however, the mountains were again worn
down to a nearly level plain. Missing between the red Chinle and the
dark rocks are many thousands of feet of rocks, some of which once
covered this surface and still occur in other regions less affected by
erosion. This gap in the rock record, which represents more than a
billion years, is known to geologists as a great unconformity. Missing
are part of the lower Proterozoic rocks, all the upper Proterozoic
rocks, all those of the Paleozoic Era, and part of those of the Triassic
Period of the Mesozoic Era. (See figs. 7 and 61.)
Traces of primitive life have been found in some Proterozoic rocks in
the form of lime-secreting algae and casts of worms, but no fossils of
more advanced types have been found because at that time the primitive
animals seemingly had not yet developed shells or skeletons. The ensuing
Paleozoic Era saw the appearance and great development of shellfish,
fish, amphibians, reptiles, and primitive plants. Some of the rock
layers of ages missing at the Monument may be seen as near as Glenwood
Springs to the northeast and Gateway to the southwest.
The Age of Reptiles
All the layers of sedimentary rocks preserved in the Monument above the
dark Proterozoic ones were deposited by wind and water during the
Mesozoic Era. This long era has been called the age of reptiles, for
reptiles, including dinosaurs (meaning terrible lizards), were then the
dominant land animals. The Mesozoic Era has been divided into three
parts—the Triassic, Jurassic, and Cretaceous Periods. Rocks of each of
these periods crop out in the Monument.
Early Landscape
By late Triassic time the Monument was part of a nearly flat plain cut
on the dark Proterozoic rocks, but there were hills or low mountains to
the northeast. Streams from these hills dropped mud, silt, sand, and
some gravel on this plain and into many small lakes that occupied the
gentle depressions. Later, these deposits hardened mainly into red
siltstone and sandstone, but thin beds of gravel were cemented to form
conglomerate, and thin beds of limestone formed in some of the shallow
lakes by the precipitation of the mineral calcium carbonate. These
rocks, which comprise the Chinle (pronounced Chin-lee) Formation, are
only 80 to 100 feet thick in the Monument but are as much as 700 feet
thick near Moab, Utah, southwest of the Uncompahgre Plateau, where the
entire formation is present. There, the Chinle rests on still older
Triassic and Paleozoic rocks—all absent in the Monument for the reasons
noted previously. In some parts of the Plateau, sandstone or
conglomerate beds in the lower part of the Chinle yield uranium ore, but
these beds were not deposited in or near the Monument.
The red color of the Chinle and some of the overlying rocks is caused by
minute amounts of iron oxide—the same pigment used in rouge and red barn
paint. Various oxides of iron, some including water, produce not only
brick red but also pink, salmon, brown, buff, yellow, and even green or
bluish green. This does not imply that the rocks could be considered as
sources of iron ore, for the merest trace of iron, generally only 1 to 3
percent, is enough to produce even the darkest shades of red.
Because it is soft, the Chinle is easily eroded into steep slopes at the
foot of high sandstone cliffs in all canyons of the Monument and on top
of the high bluffs that face The Redlands. It also forms the broad base
of Independence Monument. Rim Rock Drive crosses the Chinle three times
in the lower part of Fruita Canyon and twice in No Thoroughfare Canyon.
Fossil reptile bones, petrified wood, and freshwater shells come from
the Chinle in parts of Arizona and Utah. Reptiles probably roamed the
Monument in Chinle time, but their remains have not been located.
Ancient Sand Dunes
Still later in the Triassic Period the Monument became part of a vast
desert. Winds blowing from the northwest brought great quantities of
fine sand and piled them up into large dunes like those in the Sahara or
in Great Sand Dunes National Monument in Colorado. But like all deserts,
it was not always dry—occasional rainstorms produced many small lakes
and ponds. Some of the sand was washed into these lakes or ponds and
settled in level layers. This huge sandpile eventually hardened into the
buff and light-red sandstone that we now know as the Wingate. The shapes
of the old dunes are indicated by the steep dips of sand layers, called
crossbeds, which stand out in sharp contrast to the nearly level layers
formed in the lakes and ponds (fig. 10).
The spectacular scenery of Colorado National Monument owes its existence
largely to the 350-foot cliffs of the Wingate Sandstone (fig. 6) and to
the desert climate, which allows us to see virtually every foot of the
vividly colored rocks and has made possible the creation and
preservation of such a wide variety of fantastic sculptures. A wetter
climate would have produced a far different and smoother landscape in
which most of the rocks and land forms would have been hidden by
vegetation.
Eroded remnants of the Wingate form most of the named rock features of
the Monument and are shown in many of the photographs. Independence
Monument—a towering slab of sandstone that resembles a bridge pier (fig.
6)—is all that is left of a high narrow wall that once connected the
point east of Independence View with the high mesa north of the slab and
which once separated the two entrances of Monument Canyon. In a few
thousand years this remnant, too, may be gone.
Vertical cliffs and shafts of the Wingate Sandstone endure only where
the top of the formation is capped by beds of the next younger rock
unit—the Kayenta Formation. The Kayenta is much more resistant to
erosion than the Wingate, so even a few feet of the Kayenta, such as the
cap on top of Independence Monument, protect the rock beneath. Once this
cap has been eroded away, the underlying Wingate weathers into rounded
domes, such as the Coke Ovens.
Cold Shivers Point (fig. 53)—a toadstool shaped cap of sandstone of the
Kayenta above a vertical cliff of the Wingate—is perhaps the most aptly
titled feature of the Monument.
[Illustration: PETRIFIED SAND DUNES in Wingate Sandstone along old
Serpents Trail. Looking north across The Redlands and Grand Valley
to the Book Cliffs. Battlement Mesa on right skyline. (Fig. 10)]
The Coke Ovens (fig. 11) and Squaw Fingers were formed partly because
most of the caprock of Kayenta has been weathered away and also because
the brittle rocks were cracked along an evenly spaced set of vertical
joints. These joints trend northward between the two named features.
More rapid weathering along these joints helped form the separate
rounded domes or spires between them. Similarly, northwestward-trending
vertical joints connect and helped shape Kissing Couple, Pipe Organ, and
Sentinal Spire.
[Illustration: THE COKE OVENS, looking north from overlook beneath
Artists Point. A set of north-south joints has allowed erosion of
the Wingate Sandstone to proceed more rapidly along these zones of
weakness and has helped create the four ovens shown. Weathering away
of the protective caprock of the overlying Kayenta Formation has
produced rounded tops on all but the left-hand shaft, which is still
protected by the Kayenta. Note alcoves and arches in cliff of the
Wingate beyond, the formation of the one on the right having been
aided by removal of the underlying soft Chinle Formation. Bench
covered by piñon and juniper above Wingate is resistant thin-bedded
Kayenta Formation. Cliff above the bench is the Slick Rock Member of
the Entrada Sandstone. The Coke Ovens were named from their
resemblance to the beehive-shaped brick ovens formerly used to
convert bituminous coal into coke for smelting iron. (Fig. 11)]
Many of the cliff walls of the Wingate are vertical, some even overhang,
yet in some places the slopes are gentle enough to hold talus and to be
climbed (fig. 12). Why is this? The answer to this question is given in
a later section on “Canyon Cutting.”
Arches or shallow caves weathered out of some cliff faces of the
Wingate, particularly where the underlying Chinle Formation has been
partly scoured away. Although there are no large caves within the
Monument, there are three in a row along the road 3 miles west of the
Glade Park Post Office. One of these was inhabited until 1958 (fig. 5).
Many of the cliff faces of the Wingate are darkened or blackened by
desert varnish—a natural pigment of iron and manganese oxides, silica,
and clay.[19]
Dinosaurs left their footprints in the sands of the Wingate in parts of
the Colorado Plateau, but no tracks or fossils have yet been found in
this formation in or near the Monument.
The Rains Came
The arid climate of Wingate time was followed by a wet period, when
streams from the northeast gradually covered the sand dunes with mud,
sand, and some gravel. The sand and gravel of the stream channels were
cemented into hard sandstone and conglomerate, and the mud of the flood
plains hardened into red and purple siltstone and mudstone. The
resulting Kayenta Formation makes up the bench between the two cliffs
upon which the Visitor Center, campgrounds, and most of scenic Rim Rock
Drive were built. Here, nature was kind, for this gently sloping bench
was an ideal place to build the road from which to look down into the
deep chasms. The Kayenta also caps the broad mesas between the canyons.
It is about 350 feet thick in eastern Utah, only 45 to 80 feet thick in
the Monument, and it is absent altogether not far east of the Monument.
The reasons for the eastward thinning and ultimate disappearance of the
Kayenta and some younger rocks are given in the next section.
[Illustration: RED CANYON, looking northeast toward Grand Junction
from Red Canyon Overlook. Dark notch at the bottom of the northeast
end of the canyon is known as the Gunsight. Linear feature in the
Grand Valley beyond is the Denver and Rio Grande Western Railroad.
Prominent point near middle of Book Cliffs is Mount Garfield (Fig.
25). Battlement and Grand Mesas form left and right skylines,
respectively. Dark green bush in right foreground is Mormon Tea.
(Fig. 12)]
[Illustration: THIN BEDDED KAYENTA FORMATION protecting underlying
cliff of softer Wingate Sandstone. Rim Rock Drive is on bench of the
Kayenta close to thinner cliff of Entrada Sandstone in background.
Looking northwest from a point northeast of Monument Canyon View.
(Fig. 13)]
As noted earlier, the sandstone beds and lenses of the Kayenta generally
are coarser grained (some even contain small pebbles) and much harder
than the underlying Wingate Sandstone—particularly the lower beds of the
Kayenta, which serve as a protective capping, as shown in figure 13 and
in many of the other photographs. Unlike the dominantly fine grained,
well sorted, windblown sands of the Wingate, the coarser stream-laid
sands of the Kayenta are angular and poorly sorted, so that small grains
fill spaces between larger ones. Moreover, in addition to the calcite
cement (which also holds together the sand grains in the Wingate and
Entrada Sandstones), most of the sand grains and pebbles in the Kayenta
are covered by interconnected “overgrowths” of silica (SiO₂), which make
up about 10 percent of the rocks and serve as a nearly insoluble hard
cement.[20]
The combination of the coarse and fine grains and interlocking silica
“overgrowths” makes the Kayenta one of the most resistant rocks in the
Colorado Plateau.
In distant views of weathered outcrops the Kayenta appears to consist
mainly of thin beds or lenses of sandstone, which indeed it does, but in
some fresh exposures, such as roadcuts, the highly lenticular red
flood-plain deposits form striking features which may wedge out from 3
or 4 feet thick to a featheredge within horizontal distances of only a
few feet (fig. 14).
The Kayenta has yielded fossil bones of dinosaurs and other reptiles in
northeastern Arizona and freshwater shells in eastern Utah. As yet,
however, no fossils have been reported from it in or near the Monument.
Another Gap in the Rock Record
Following the wet interval when the Kayenta Formation was deposited over
wide areas of the Colorado Plateau by streams, the Plateau once again
became a vast desert, and this time the dry climate persisted from the
Late Triassic into the Jurassic. The howling winds piled up enormous
sand dunes, layer upon layer, to a total thickness of more than 2,200
feet at Zion National Park, and as much as 500 feet remains in eastern
Utah and parts of southwestern Colorado. This immense sandpile
eventually was cemented by calcite into the Navajo Sandstone.
[Illustration: KAYENTA FORMATION, showing lenses of hard channel
sandstones and wedge of red siltstone and mudstone. Along road cut
of Rim Rock Drive near head of main stem of Ute Canyon. Vertical
grooves remain from drill holes used in blasting roadcut. (Fig. 14)]
Beautifully sculptured remains of the Navajo are featured attractions at
Zion, Capitol Reef, and Arches National Parks, Rainbow Bridge, Navajo,
and Dinosaur National Monuments; border many miles of beautiful Lake
Powell; and form the eastern flank of the San Rafael Swell. For reasons
to be explained, this sandstone thins to the northeast, and is absent
entirely at about the Utah-Colorado State line, some 35 miles southwest
of the Monument. Thus, in the Monument, the Navajo, most of the Kayenta,
and the lower part of the Entrada Sandstone are missing at another gap
in the rock record, as shown in figure 15.
[Illustration: GAP IN THE ROCK RECORD, between Kayenta Formation
below 3½- × 6-inch green notebook and Slick Rock Member of Entrada
Sandstone above. The reasons for this gap are given in the text on
page 38. That this is an erosional unconformity is clearly indicated
by the uneven top of the Kayenta, particularly to the left of the
notebook. Note solution pits and openings in the Entrada near top of
photograph. (Fig. 15)]
How is it possible that the Navajo Sandstone is more than 2,200 feet
thick in Zion National Park, is several hundred feet thick in much of
the Plateau in Utah and parts of southwestern Colorado, yet is absent
entirely, together with a considerable thickness of younger rocks in and
near Colorado National Monument? How much of the missing strata once
were present in the Monument is not known, but it seems clear that at
least part was present but was eroded away before the Entrada Sandstone
was deposited. There is evidence[21] that following the deposition and
consolidation of the Navajo Sandstone the Plateau and adjacent areas
were uplifted, tilted gently westward, and eroded for a considerable
period of time. Erosion naturally was most pronounced in the eastern
areas, including the Monument, where the uplift was greatest. Thus, in
the northeastern part of the Plateau all the Navajo and most of the
Kayenta were eroded away, and erosion continued there while the lowest
member of the Entrada, the Dewey Bridge Member, and the lower part of
the overlying Slick Rock Member were being laid down in the Moab, Utah,
area.[22] This old erosion surface is clearly visible in many places
along the cliff wall on the southwest side of Rim Rock Drive between the
Visitor Center and Kissing Couple.
The reduction in thickness of the Navajo Sandstone from southwest to
northeast and absence of the Navajo and some younger rocks in and near
the Monument are shown on an isometric (three dimensional) block diagram
prepared by artist John R. Stacy and me, which is displayed in the
Museum of the Visitor Center. This block diagram portrays the surface
and subsurface rocks from Zion National Park, Utah, to Black Canyon of
the Gunnison National Monument, Colo., via Capitol Reef National Park,
the Henry Mountains, and Colorado National Monument. Throughout the
Plateau and parts of adjacent areas, the erosion surface on top of the
Navajo Sandstone is covered by scattered pebbles of chert—a hard variety
of silica (SiO₂) derived from cherty beds of freshwater limestone in the
Navajo.[23] Where the Navajo has been completely eroded away and the
ancient erosion surface is on the Kayenta Formation, as in Colorado
National Monument, scattered pebbles (some of which are chert) derived
from the conglomerate lenses in the Kayenta are found locally on the old
surface.[24]
Because of this gap in the rock record we will continue part of our
story farther west, where the rock record is more nearly complete.
The Sea to the West
In Middle Jurassic time the land now called central Utah, which then was
the eroded surface of the Navajo Sandstone, sank beneath an arm of a
shallow sea that came in from the north, and most of the area remained
beneath this sea until Late Jurassic time. Sediment carried into this
sea and into bordering lagoons and estuaries later hardened into the
sedimentary rocks of the Carmel Formation, Entrada Sandstone, and Curtis
and Summerville Formations. The Carmel and Curtis contain abundant
marine fossils of Middle Jurassic age, and in central Utah the
intervening unfossiliferous Entrada also is believed to have been
deposited in or near the sea, and the unfossiliferous Summerville
Formation probably was deposited upon a tidal flat that was submerged
part of the time.
Deposits and Events East of the Sea
In eastern Utah, east of the ancient Jurassic sea, the Entrada Sandstone
is entirely unfossiliferous, was partly water laid and partly wind
blown, and has been divided into three distinctive parts, which in
ascending order are the Dewey Bridge, Slick Rock, and Moab Members.[25]
In and near the Colorado National Monument, the long period of erosion
discussed in a preceding section probably continued well into the
Jurassic, so only the upper part of the Slick Rock Member and the
overlying Moab Member were deposited on the eroded surface of what
little remained of the Kayenta Formation (fig. 14).
The Slick Rock Member was named from its occurrence at and near the
mining town of Slick Rock, Colo., which originally was named after the
appearance of the rock because it generally forms slick, smooth cliffs.
It reminds one of the chicken and egg conundrum. The Slick Rock is
composed mainly of sand dunes that were piled up on the eastern shore of
the Jurassic sea by winds blowing from the northeast. Occasional rainy
spells created lakes and ponds in which some of the sand was laid down
in level beds. This pile of sand later hardened into the cliff-forming
Slick Rock Member, which looks something like the Wingate but is
generally only half as thick, weathers into less abrupt cliffs, is
mostly salmon red, and is almost free of joints. The joints in the
Wingate (fig. 11) probably resulted from the uplift and tilting of the
Plateau before the long period of pre-Entrada erosion; whereas the land
seems to have been more stable during Entrada time. The Slick Rock is
cemented with calcium carbonate (CaCO₃), which is soluble even in weak
acid, such as rain or snow water containing dissolved carbon dioxide.
For this reason solution openings or pits occur in some of the cliff
faces, the most striking of which are those shown near the top of figure
15.
The Slick Rock Member of the Entrada Sandstone forms a line of cliffs
and isolated monoliths that are second in height and grandeur only to
those of the Wingate. The Member is best displayed southwest of Rim Rock
Drive between the Visitor Center and the Coke Ovens and along the
western arm of Ute Canyon (fig. 16). It also forms the Saddlehorn just
south of the camp and picnic grounds near the Visitor Center (fig. 50).
Most of the smooth cliff faces show both the steeply dipping crossbeds
of the old sand dunes and the flat-lying beds of the lake or pond
deposits.
[Illustration: ENTRADA SANDSTONE, just above normally dry waterfall
in west arm of Ute Canyon. Note smooth unjointed cliff of Slick Rock
Member protected at left by overhanging basal bed of Moab Member,
which forms about lower half of slope in distance. Upper part of
distant slope is the Summerville Formation overlain by Salt Wash
Member of the Morrison Formation. Note Slick Rock at left resting
upon eroded crossbedded sandstone in Kayenta Formation, in which the
canyon was cut. (Fig. 16)]
The overlying Moab Member of the Entrada is a white level-bedded
sandstone that generally weathers into stairsteps or ledges. One of the
best exposures of the Moab Member is shown in figure 17, but good
exposures also are seen along the west side of Rim Rock Drive just
northeast of the Coke Ovens Overlook. In some places the Moab Member
forms cliffs continuous with those of the underlying Slick Rock Member.
It appears to consist of hardened beach or lagoon sand that was
deposited along the eastern shore of the sea, which suggests that the
sea extended farther east during Moab and Summerville times than it did
during Dewey Bridge and Slick Rock times. Like the Slick Rock, the Moab
also is cemented by calcium carbonate, but the lower sandstone ledges of
the Moab Member are more resistant to erosion than the Slick Rock
Member, so the Moab helps preserve the underlying cliffs. The top of the
Moab Member forms patches of bare pavement east of the Monument, known
as the “Slick Rim,” which may be observed from the Little Park Road.
[Illustration: MOAB MEMBER OF ENTRADA SANDSTONE, showing typical
steplike weathering. In west arm of Ute Canyon about a quarter mile
above the view shown in figure 16. Moab Member caps and protects
overhang of Slick Rock Member. Moab is overlain by unexposed slope
of Summerville Formation and lower part of Morrison Formation. (Fig.
17)]
Although the Slick Rock Member normally is salmon colored or pink, the
upper half of an outcrop just north of the highest point on Rim Rock
Drive at the head of main Ute Canyon has a distinctly mottled
appearance, wherein much of the color has been leached to white, but
irregular splotches of color appear in the dominantly white upper part,
and white splotches appear in the colored part, as shown in figure 18.
By way of contrast, in an outcrop of the two members of the Entrada
about 2 miles north of the Glade Park Store and Post Office (fig. 19),
the entire Slick Rock Member is as white as the Moab Member, and the
former is white for some distance to the east. Why is the salmon color
entirely missing from the Slick Rock near Glade Park, partly missing in
figure 18, but present virtually everywhere else in and near the
Monument? The answers to this seeming mystery involve events that
occurred long ago, so only the high points will be touched upon here.
[Illustration: MOTTLED SALMON-AND-WHITE SLICK ROCK MEMBER, overlain
by white level-bedded Moab Member, on west side of Rim Rock Drive
about four-tenths of a mile north of head of main Ute Canyon. (Fig.
18)]
It seems reasonable to suppose that the Slick Rock Member at both
localities originally was salmon colored or pink, as it is everywhere
else, but that later, the coloring agent, red ferric iron oxide (Fe₂O₃),
was chemically reduced, or leached to ferrous iron oxide (FeO), by
acidic ground water, and was carried away to the northeast by the slowly
moving ground water. But as I have already pointed out, the cliff
exposures of the sandstones are now bone dry, so what happened to the
ground water and why was it acidic here and not elsewhere?
[Illustration: WHITE ENTRADA SANDSTONE, in outcrop just east of
gravel road about 2 miles north of Glade Park Store and Post Office.
Reasons for absence of salmon color in Slick Rock Member are given
in text. (Fig. 19)]
Before the cutting of the deep canyons of the Monument, which followed
the last major uplifts of the region accompanied by bending and breaking
of the rocks, the now dry sandstones were saturated with ground water
that moved very slowly northeastward. Somewhere to the southwest the
Entrada Sandstone seemingly took in water containing dissolved hydrogen
sulfide gas (H₂S), changing the ground water to a weak acid. The H₂S
could have been produced by a type of anaerobic bacteria that has the
ability to reduce dissolved sulfates (SO₄⁻²) in water to the dissolved
hydrogen sulfide gas, thereby obtaining needed oxygen.
The next questions you might logically ask are (1) if the above
deductions have any merit, how do we know the acid water was caused by
dissolved hydrogen sulfide,[26] (2) what is the source of the sulfate
ions (SO₄⁻²) from which the H₂S was obtained, and (3) why is the color
of the Slick Rock Member in figure 19 completely reduced to white
whereas that in figure 18 is only partly reduced in the upper part?
Although the ground waters from artesian wells in the Grand Junction
area contain small amounts of sulfate as do most ground waters, the
amount needed for the results observed more likely came from solution of
the common mineral gypsum (calcium sulfate containing some water,
CaSO₄·2H₂O). The overlying Summerville and Morrison Formations contain
some gypsum in many places in Utah, so it is not improbable that these
formations contain gypsum locally in Colorado. If so, sulfate-bearing
water could have percolated downward into the Entrada at some point
southwest of Glade Park. But as this must have happened several million
years ago, the clues as to just where this occurred have grown quite
cold.
Seemingly, the color in the Slick Rock Member near and east of Glade
Park was entirely removed by the process described, but the very slow
moving ground water had time to leach only the upper part of the Slick
Rock (the most permeable part) in Ute Canyon before the process was
halted forever by the draining of water from these beds by canyon
cutting.
Shortly before the Jurassic sea to the west dried up, silt, mud, and
some sand were carried into either a shallow arm of the sea or a broad
bay or lagoon near it, and later the silt, mud, and sand hardened to
become the Summerville Formation. The Summerville is only 40 to 60 feet
thick in the Monument but is much thicker in Utah.
The Summerville Formation is so soft that it weathers very rapidly and
hence is exposed at only a few places. It is best displayed in the high
roadcut at Artists Point and along the road to the south for the next
mile (fig. 20), but it is also exposed in roadcuts along the west arm of
Ute Canyon. Even the thinnest beds of the Summerville can be traced for
hundreds of yards, and individual beds have a nearly constant thickness
for such distances. This greatly facilitated the detailed measurement of
a section of the Summerville[27] by my son Bill and me from Artists
Point to the base of the overlying Morrison Formation about a mile
south. Using a 6-foot folding steel rule we measured and described each
thin bed from some key bed at about ground level to one at eye level,
followed the upper key bed southward to ground level, then repeated the
process until the entire 54 feet had been measured and described.
[Illustration: SUMMERVILLE FORMATION, at Artists Point (fig. 3).
Base of formation rests upon Moab Member of Entrada just beneath the
pavement. Note geologist’s pick resting upon lower ledge of
sandstone just to the left of middle. Top of the Summerville here
has been removed by erosion. (Fig. 20)]
The Summerville at the type locality in the San Rafael Swell, Utah, is
much thicker than in the Monument and contains many chocolate-brown
beds; but the Summerville exhibits the same lateral continuity of even
the thinnest beds. Thin sedimentary beds of such uniform thickness are
thought to have accumulated in relatively quiet bodies of water. If you
look at the undersides of some of the blocks of hard light-gray
sandstone that have broken off, you may see corrugations like those on
some metal barn roofs. These are ripplemarks produced by wave or current
action while the sand was still loose, which indicates that the water
was not always entirely quiet. Although much of the Summerville is red,
you will see beds of many other colors including gray, blue gray,
greenish gray, chocolate brown, and reddish brown.
Dinosaurs Roam the Monument
In Late Jurassic time the sea to the west eventually dried up, either
because it was filled with sediments or because the land rose above sea
level, or both. This brought about a change from the parallel bedding in
the marginal marine environment of the Summerville to irregular
stream-channel sandstones, flood-plain silts and muds, and freshwater
lake deposits.
Streams from higher lands to the south brought in mud, silt, and sand
that piled up hundreds of feet thick over thousands of square miles,
including the Monument. These sediments were later compacted into the
brightly colored siltstone, mudstone, sandstone, and limestone now known
as the Morrison Formation. The colors are about the same as those of the
Summerville. Algae and other microscopic organisms extracted calcium
carbonate from the lake waters, and when they died this material settled
on the lake bottoms to make limestone.
The soft siltstone and mudstone of the Morrison Formation weather
rapidly into steep or fairly steep slopes, but the harder beds of
sandstone, most of which are in the lower third of the formation, known
as the Salt Wash Member, are sculptured into bold ledges or low cliffs.
The generally softer upper two-thirds of the formation is called the
Brushy Basin Member. The Morrison is best exposed in and southeast of
The Redlands, where the bare rocks are carved into badlands like the
famous ones of South Dakota. Both the Fruita Canyon and No Thoroughfare
Canyon approaches to the Monument pass typical badlands in the Morrison.
The entire 600 feet of this formation is best seen in the high bluff on
the east side of the mouth of No Thoroughfare Canyon (fig. 21).
[Illustration: MORRISON FORMATION, on east side of mouth of No
Thoroughfare Canyon. Forty feet of Summerville Formation at base is
concealed by slope wash, but underlying white- and salmon-colored
members of Entrada Sandstone are clearly exposed at lower left.
Protective caprock at upper right is lowermost sandstone of
Cretaceous Burro Canyon Formation. Upper two-thirds of Morrison is
typical of the Brushy Basin Member; lower one-third is not typical
of the Salt Wash Member, which generally contains more and thicker
lenses of sandstone, some of which are just around the corner to the
right. Mesa on left skyline is above Serpents Trail in the Monument.
Looking west from Little Park Road. See also figures 55 and 60.
(Fig. 21)]
In parts of the Colorado Plateau southwest of the Uncompahgre Plateau,
the sandstone lenses in the Salt Wash Member of the Morrison contain
uranium and vanadium ore associated with carbonaceous matter, including
coalified wood. No ores have been found in or near the Monument
presumably because such carbonaceous matter, which helped precipitate
the ores, is lacking on the northeastern side of the Uncompahgre
Plateau.
Some of the beds of siltstone and mudstone in the Brushy Basin Member of
the Morrison shown in figure 21 contain bentonite, a clay derived from
the decomposition of volcanic ash, which indicates the presence of
active volcanos in or near the Plateau at the time these beds were
deposited. Bentonite swells when wetted, so it is widely used in
well-drilling muds, sealing canals, etc. Some bentonitic material has
been dug from the Brushy Basin along the Little Park Road just south of
the point from which the photograph in figure 21 was taken and was used
for sealing irrigation canals in the Grand Valley.
The Morrison is not well exposed in the Monument, as the formation is
restricted to the higher parts where most of it is hidden by vegetation.
The lower part is seen in roadcuts and outcropping ledges along a high
stretch of Rim Rock Drive between Artists Point and the head of the west
arm of Ute Canyon, where sandstone lenses in the Salt Wash Member are
especially thick.
The climate during Morrison time was wet enough to support abundant
vegetation along the many lakes and streams—at least enough to feed the
hungry dinosaurs and other reptiles that roamed the area. Many bones and
parts of several skeletons of dinosaurs have been found in the Morrison
at several places in The Redlands not far northeast and northwest of the
Monument.
The most famous dinosaur locality near the Monument is Riggs Hill where,
in 1900, the late Elmer S. Riggs of the Field Columbian Museum (now
Field Museum of Natural History) dug out part of the first known
skeleton of a huge _Brachiosaurus_ (fig. 22). This discovery made quite
a splash in the scientific world, for it was the first and only type of
dinosaur found whose front legs were longer than its hind legs. The
fossilized thigh bone (femur) alone is 6 feet 8 inches long and weighs
549 pounds; the arm bone (humerus), though incomplete, is even longer.
The ribs are 9 feet long. A bronze plaque now marks the site of the
excavation (fig. 39).
In 1901, Riggs removed all but the forepart of a skeleton of
_Apatosaurus_ from the southeast side of a large hill of the Morrison
Formation just south of the old Fruita bridge. Riggs also found remains
of _Diplodocus_, _Camarasaurus_, and _Morosaurus_, and, in 1937, Al
Look, prominent writer and amateur paleontologist of Grand Junction, and
Edwin L. Holt, an instructor in Mesa College at Grand Junction, found
the closely associated remains of _Allosaurus_, _Stegosaurus_, and
_Brachiosaurus_ at the western end of Riggs Hill. Dinosaurs generally
are thought of as huge creatures—many were huge indeed (fig. 23)—but
they came in various sizes and some were quite small.
An interesting Late Jurassic vertebrate fossil locality in the Salt Wash
Member of the Morrison Formation, about 3 miles northwest of the West
Entrance of the Monument and about 3 miles southwest of Fruita, was
discovered in June 1975 by George Callison, Associate Professor of
Biology and Research Associate in Vertebrate Paleontology at the
California State University at Long Beach. During the summers of 1975
and 1976 Dr. Callison and his assistants removed the closely associated
skeletal remains of many small, primitive mammals and both small and
large dinosaurs and other reptiles. Part of the results were presented
in an unpublished manuscript.[28] During the summer of 1977 and later,
additional mammalian fossils were removed by Callison and assistants and
additional reptilian fossils were removed by Lance Erickson,
paleontologist of the Historical Museum and Institute of Western
Colorado (fig. 2). Hopefully, the work will be continued with the aid of
grants from several sources.
[Illustration: EXCAVATING TYPE SPECIMEN OF _BRACHIOSAURUS
ALTITHORAX_ RIGGS from south side of Riggs Hill. Photograph taken in
1900, reproduced by permission of the Field Museum of Natural
History (Chicago). See also figure 39. (Fig. 22)]
The locality, which covers parts of about 180 acres of public land
administered by the Bureau of Land Management, has been fenced and
posted to discourage vandalism, and has been designated the Fruita
Paleontological Area.
In order to evaluate the importance of the locality and to make plans
for its future development and protection, the Bureau of Land Management
held the Fruita Paleontological Workshop on March 28-30, 1977, to which
were invited several renowned vertebrate paleontologists and
archaeologists together with interested local personnel of the Bureau,
the National Park Service, and the Museum. All remarks and prepared
speeches were taken down by a shorthand reporter and were reproduced for
the attendees in the 83 page unpublished “The Fruita Paleontological
Report.”
[Illustration: SKELETONS OF TYPICAL DINOSAURS OF MORRISON
FORMATION.[29] _A_, _Camptosaurus_, a small dinosaur about 11 feet
long; _B_, _Apatosaurus_, a gigantic dinosaur about 76 feet long;
_C_, _Allosaurus_, a large carnivorous dinosaur about 30 feet long;
and _D_, _Stegosaurus_, a large armored dinosaur about 24 feet long.
(Fig. 23)]
The close association of Late Jurassic mammalian and reptilian fossils,
as found at the Fruita site, is of considerable interest and importance,
but is by no means unique, for similar associations occur elsewhere in
Colorado, and in Wyoming, Europe, and Africa. Of those in the United
States, the quarry at Como Bluff, near Laramie, Wyo., is considered by
most of the experts to be the most outstanding. Of the material
unearthed at Fruita thus far, which includes bones of some of the large
dinosaurs found earlier by Riggs, remains of some of the smaller
dinosaurs and a complete skull of the moderately large flesh eater
_Ceratosaurus_ are considered the most important.
Freshwater clam and snail shells abound in some beds of the Morrison,
particularly in limestones, and occur sparingly in other types of beds.
The shells occur mainly in The Redlands, particularly about 1½ miles
west of the Fruita bridge. Some of these shells that are filled with
agate are sought by rockhounds.
Dinosaurs on the Move
The wet climate of Late Jurassic time was followed by arid or semiarid
climate in the Early Cretaceous. Streams continued to deposit gravel,
sand, silt, and mud, but at a much slower rate. These deposits
eventually hardened into the conglomerate, sandstone, and green shale or
siltstone of the Burro Canyon Formation. This formation, together with
part of the overlying Dakota Sandstone, caps Black Ridge, the highest
part of the Monument (7,000 feet) about a mile west of the Coke Ovens.
Several airway beacons on this high ridge may be seen for many miles.
The Burro Canyon is best seen below the Monument on the west side of
Monument Road along the lower part of No Thoroughfare Canyon, where it
is about 60 feet thick (fig. 24).
[Illustration: BURRO CANYON FORMATION AND DAKOTA SANDSTONE, along
west side of No Thoroughfare Canyon, about 2½ miles northeast of the
Monument’s East Entrance. Basal sandstone above road and unexposed
green shale (brown in photograph) comprise the Burro Canyon, here 58
feet thick. White band two-thirds the way up the slope is 40-foot
basal conglomerate of the Dakota Sandstone, above which is 58 feet
of carbonaceous shale, a 14-foot bed of sandstone, and 17 feet of
sandy shale to the top of the hill. The top of the Dakota has been
eroded away. (Fig. 24)]
A few fossil plants and shells have come from the Burro Canyon
Formation, but the seeming absence of dinosaur bones suggests that
possibly these reptiles had to move to areas of greater precipitation,
where food was more abundant. Some dinosaurs may have lived in the area
at this time, but their bones either were not fossilized or they have
not yet been found.
Yet Another Gap in the Rock Record
Deposition of the Burro Canyon Formation was brought to a close by
another uplift of the Plateau, and of course the uplift was followed by
another period of erosion, which continued through the end of Early
Cretaceous time. As noted in the caption for figure 24, seemingly all
but 58 feet of the Burro Canyon was eroded away, but 120 feet remains
along East Creek, only about 12 miles to the southeast, which suggests
that the old erosion surface was a bit uneven. That this period of
erosion was of considerable duration is suggested by the abundance of
the white clay mineral, kaolinite, beneath and in the overlying white
basal conglomerate of the Dakota Sandstone. This type of clay commonly
results from prolonged weathering of many types of rocks and indicates
that the period of pre-Dakota erosion was of long duration.
Peat Bogs
By the beginning of Late Cretaceous time the eroded surface of the
Monument was part of a low plain near sea level, and the sea was
gradually encroaching from the east or northeast. Gravel and sand
carried in by streams combined with the white kaolinite on the surface
to form the 40-foot basal conglomerate of the Dakota Sandstone (fig.
24).
As the land gradually subsided nearer to sea level, swamps which were
formed along the coast supported considerable vegetation. As the trees
and plants died and were covered by silt and mud, they gradually changed
to peat which finally became compacted into coal and brown or black
coaly shale containing plant remains. You can dig out some of this coal
and perhaps find some plant remains near the top of the west canyon wall
just below the highest sandstone bed in figure 24, which is outside the
Monument.
For awhile the coast alternately sank slightly below and rose slightly
above sea level. Beach sand covered the swamp deposits, then more swamp
deposits covered the sand. Some of the sand contains seashells, such as
oysters and clams.
Except on Black Ridge, the Dakota has been entirely eroded from the
Monument, but it crops out with the underlying Burro Canyon in a series
of low hills south of the Colorado River. The Dakota Sandstone is about
200 feet thick.
The Sea Covers the Plateau
Still later in the Cretaceous Period the whole region sank beneath the
sea and stayed there a long time. Silt and limy mud were piled layer
upon layer on the sea floor and hardened into the gray and black Mancos
Shale. Thin layers of sand were cemented into sandstone, and layers of
calcium-carbonate mud became chalk or limestone. Seashells and bones of
sharks and seagoing reptiles have been found in the Mancos in many
places.
The Mancos and all younger rocks have been stripped off the Monument,
but they may be seen one after the other as you travel northeastward.
Thin remnants of the Mancos cap low hills just south of the Colorado
River, and the entire 3,800 feet of the Mancos underlies the Grand
Valley and Book Cliffs. The upper part is clearly exposed in the
towering, barren Book Cliffs, where the soft shale is protected by a
caprock of hard sandstone—the lowermost unit of the overlying Late
Cretaceous Mesaverde Group (fig. 25).
The Sea’s Final Retreat
Slow uplift of the Plateau, including the Monument region, caused the
gradual retreat of the Mancos sea. Deposition of mud on the sea bottom
gave way to deposition of beach sand, coal swamps, and then more beach
sand and coal swamps. Finally, in Late Cretaceous time, the sea withdrew
entirely, never again to return to the Colorado Plateau region.
Streams deposited sand, silt, and mud on the newly uplifted coastal
areas. All these deposits, including some high-grade bituminous coal
that was formed in the swamps, we now know as the Mesaverde Group. The
thick cliff-forming sandstones of this unit are beautifully displayed in
DeBeque Canyon of the Colorado River between Palisade and DeBeque, just
upstream from the Grand Valley. There are several active coal mines in
the Mesaverde between Palisade and Cameo, and outcrops of coal may be
seen on the east side of the road just south of Cameo. The electric
generating station of the Public Service Company of Colorado at Cameo is
conveniently situated over a coal mine and next to the Colorado River,
which supplies cooling water.
[Illustration: MOUNT GARFIELD, a prominent point on the Book Cliffs
bordering the northeastern side of the Grand Valley. Slopes are
Mancos Shale; ledge about halfway upslope is the toe of an ancient
landslide deposit of Mesaverde sandstone blocks marking the level of
an ancestral Grand Valley; capping beds of sandstone at crest are
basal beds of Mesaverde Group. (Fig. 25)]
[Illustration: PHOTO INDEX MAP, showing localities where most of the
photographs were taken. Arrows point to distant views. Numbers refer
to figure numbers. (Fig. 26)
Photographs for four figures are not shown because figures 5, 25 and
36 were taken outside the map borders and figure 1 was taken at an
undisclosed locality in the monument]
The remains of dinosaurs have been discovered in rocks of this age
elsewhere, but near the Monument only their tracks have been found. Some
of these, in coal mines along the Book Cliffs and near Cedaredge, are 38
inches across and their placement indicates an incredible stride of 16¼
feet! Had there been highways in Mesaverde time, this bipedal giant
could have crossed them in two strides.
Both the Mancos and Mesaverde once covered the Monument area but were
removed long ago by erosion.
End of the Dinosaurs
The end of the Cretaceous Period was also the end of the dinosaurs.
Exactly why the “terrible lizards” died out after dominating the world
for more than 150 million years is not known for sure, but many guesses
have been made.
One likely idea is that widespread uplift and mountain building that
began late in Cretaceous time, accompanied by changes in climate, may
have greatly reduced the supply of soft edible plants. If so, it is easy
to imagine how huge dinosaurs accustomed to a ton or more of lush plant
food each day would soon starve to death.
Many dinosaurs were vegetarians. As they died out, the flesheaters, such
as _Tyrannosaurus_, soon ran short of food also, and probably began to
eat each other. _Tyrannosaurus_ closely resembled the Jurassic
_Allosaurus_ shown in figure 23, except that _Tyrannosaurus_ was much
larger and more formidable—in fact it probably was the most terrible
predator that ever roamed the surface of the Earth. The dinosaurs had
become too highly specialized to their environment to adapt themselves
to changes of this kind.
Another fascinating notion is that the growing population of small
primitive mammals devoured dinosaur eggs (which were left unattended
like those of turtles and alligators) nearly as fast as mamma dinosaur
could lay them. But whatever the reason, it is clear that some worldwide
condition caused the gradual extinction of the ponderous
over-specialized dinosaurs and allowed the rise to power of the next
types of animals destined to rule the Earth—the brainier and more
adaptable mammals.
At this time the rocks were gently bent into upfolds, called anticlines
or arches, and downfolds, called synclines or basins (fig. 27). One
upfold that began to take form was the Uncompahgre arch, the crest of
which shapes Piñon Mesa just south of the Monument. But this gentle
upfold was to grow larger and to have its flanks wrinkled and broken in
the next geologic era—the Cenozoic.
The Age of Mammals
The beginning of the Cenozoic Era 65 million years ago—give or take a
few million years—marked the beginning of a long span of geologic time
during which mammals became the ruling land animals. Remains of some
small primitive mammals have been found in Mesozoic rocks (p. 50), but
these tiny newcomers did not have a chance to flourish until the
formidable dinosaurs died out.
The Cenozoic Era is divided into the long Tertiary Period—The Age of
Mammals—and the short (about 2 million years) Quaternary Period—The Age
of Man. The Tertiary in turn is divided into five epochs—the Paleocene,
Eocene, Oligocene, Miocene, and Pliocene (fig. 61). Events during parts
of the Tertiary Period had an important bearing upon the Monument even
though no rocks of this period now occur in the area.
[Illustration: COMMON TYPES OF ROCK FOLDS. Top, anticline, or
upfold; closed anticlines are called domes. Middle, syncline or
downfold; closed synclines are called structural basins. Bottom,
monocline, a common type on the Plateau in which the dip of the beds
changes in amount but not in direction; axes may be mapped along
trends of upper fold, middle flexure, or lower fold. Top and middle
diagrams from Hansen (1969, p. 31, 108). (Fig. 27)]
Early Deposits and Events
The broad inland basins that were formed late in the Cretaceous Period
received sand, silt, and mud brought in by streams from the uplifted or
folded areas. These materials became compacted into the Wasatch
Formation—the red or pink rock from which Bryce Canyon National Park was
sculptured. One such basin lay just northeast of the Monument. The
Monument probably was covered by some of these stream deposits after the
main basin was partly filled.
The mammals that roamed the area during the Paleocene Epoch were
primitive, but more advanced forms appeared later, in Eocene time. Some
of their fossil remains have been found in the Wasatch Formation in
Plateau Creek Valley north of Grand Mesa and near Rifle, about 60 miles
northeast of Grand Junction. The entire 5,000 feet of the Wasatch may be
seen along U.S. Highway I-70 between the towns of DeBeque and Grand
Valley, and much of it helps support towering Grand and Battlement
Mesas.
Lake Uinta
In Eocene time the northern part of the Colorado Plateau sagged downward
and gradually filled with water until it became a huge lake, now known
as Lake Uinta. The waters in it teemed with plants and animals,
particularly micro-organisms such as algae, whose remains, coated with
calcium carbonate, settled to the bottom along with the sand, silt, and
mud washed into the lake by streams. These sediments compacted into the
remarkable Green River Formation which contains, among many rock types,
large deposits of rich oil shale.
The light-colored Green River Formation, which is about 3,800 feet
thick, may be seen from U.S. Highway I-70 in the upper part of the
towering Roan Cliffs on the northwest side of the Colorado River between
DeBeque and Rifle. It also underlies the volcanic caprock of Grand and
Battlement Mesas. John R. Donnell, of the U.S. Geological Survey,
estimated that the oil shale in the Piceance Creek Basin, northwest of
the Colorado River alone, contains more than one trillion barrels of
oil. The Monument was at or near the south shore of this lake, and may
have been covered with a few hundred feet of the Green River Formation.
The Mountains Rise Again
Lakes, like mountains, are temporary things. Even as lakes are forming,
sediment begins to fill them until ultimately they are obliterated. So
it was with Lake Uinta. Sometime after this lake dried up, the Earth’s
crust again became restless. The gentle folds that were formed late in
the Cretaceous were lifted higher and bent more sharply, and the flanks
of some folds were wrinkled and broken (figs. 27, 28). The sharply bent
or broken rocks along the northeastern border of the Monument are
thought to have been deformed mainly at this time, but in part both
earlier and later. That pronounced folding of the rocks followed the
deposition of the Eocene Green River Formation is clearly shown along
the Grand Hogback monocline between the towns of Rifle and Meeker,
Colorado, where the once flat lying beds of the Green River and Wasatch
Formations now stand vertical.
The folds and faults along the northeastern border of the Monument,
which are shown on the geologic map (fig. 8), are discussed briefly
here—more details are given later in “Trips through and around the
Monument.” The folded and faulted northeastern border of the Monument,
which is shown in figure 29 and in several ensuing photographs, is
believed to have resulted from renewed uplift of the area southwest of
the folds and faults, including the Monument. The Redlands fault (figs.
8, 29, 37, 38, 40, 41) generally is a normal fault but locally is a
reverse fault, as discussed on page 92 and as shown in figure 40 and in
the cross section of figure 8. This fault has a maximum vertical
displacement of 700 or 800 feet, but dies out in scissors fashion at
each end. Beyond the end of the Redlands fault in the upper right of
figure 29 may be seen another unbroken monocline. A close-up view of the
northwestern end of this fold in shown in figure 30.
[Illustration: COMMON TYPES OF FAULTS. Top, normal, or gravity,
fault which generally results from tension in and lengthening of a
segment of the Earth’s crust, which allows the lower block to
subside. However, some normal faults, particularly some that are
vertical or nearly so, may result from uplift of the upper block.
Low-angle reverse faults generally are called overthrust faults or
simply overthrusts. In both the normal and reverse faults note
amount of displacement and repetition of strata. Displacement of
such faults may range from a few inches to many thousands of feet,
and in overthrusts may reach many miles. From Hansen (1969, p. 116).
(Fig. 28)]
If we proceed about a quarter of a mile northeast of the point from
which figure 30 was taken, walk about 50 feet north, and look to the
northwest, we see quite a different structure, for here the gentle lower
fold of the Lizard Canyon monocline has become the east end of the
Kodels Canyon fault (fig. 31).
[Illustration: LADDER CREEK MONOCLINE AND REDLANDS FAULT, telephoto
view looking northwest from point near Little Park Road east of the
Monument. No Thoroughfare Canyon in foreground, which is bordered on
the left by northeastward-dipping beds of Wingate Sandstone at
northwest end of Ladder Creek monocline. The old Serpents Trail, the
lower part of which is barely visible, ascends this dipping block of
rock. The dark Proterozoic rocks form the flat-topped bluff to the
right and are exposed by the Redlands fault which lies just above
the sharply upturned remnants of the Wingate Sandstone. (Fig. 29)]
[Illustration: LIZARD CANYON MONOCLINE, looking southeastward across
mouth of Lizard Canyon from southeasternmost loop of Rim Rock Drive
just before it ascends Fruita Canyon. Note gentle lower bend at
lower left and sharper upper one at upper right. Lower bend changes
to Kodels Canyon fault in Fruita Canyon behind camera station. Grand
Mesa forms left skyline. (Fig. 30)]
[Illustration: KODELS CANYON FAULT, looking northwest across mouth
of Fruita Canyon from point on Rim Rock Drive just described in
text. Here, along a normal fault dipping steeply northeastward, the
350-foot cliff of Wingate Sandstone at upper left has been sheared
and squeezed into only a few feet of broken rock overlain by a steep
slope of the Kayenta Formation covered by piñon and juniper. The
thinner cliff at right is the Entrada Sandstone which belongs high
atop the cliffs at left. Book Cliffs form distant skyline at right.
(Fig. 31)]
If you doubt that figure 31 shows a fault, a glance at figure 32 in the
next major canyon eight-tenths of a mile to the northwest should
convince you. Here, on the northwest side of Kodels Canyon, the Wingate
was not thinned but was rent completely asunder by the vertical Kodels
Canyon fault (fig. 32). Kodels Canyon is not readily accessible to
visitors.
The Lizard Canyon monocline, Kodels Canyon fault, and other structures
are clearly shown in the stereoscopic pair of aerial photographs in
figure 33.
Another structural feature within the Monument is the Glade Park fault
(fig. 8), which lies mainly south of the Monument but just cuts across
the south end of No Thoroughfare Canyon in the latest addition to the
Monument. It is well shown both from the air and the ground in figures
58 and 59. It is unique among all the major faults in the area in that
the rocks south of the fault subsided with respect to those on the north
side.
[Illustration: KODELS CANYON FAULT, looking northwestward across
canyon of same name. Base of Wingate cliff on left is just about
opposite the top of the Wingate on right. Here, nature was kind to
the geologist, for the vertical displacement (rise of left side with
respect to right side) is virtually the thickness of the Wingate
Sandstone—about 350 feet. The Wingate on the right is lighter
colored than that on the left seemingly because rockfalls removed
desert-varnish-coated rocks and exposed the true color of the
sandstone. (Fig. 32)]
[Illustration: GEOLOGIC STRUCTURES AT FRUITA ENTRANCE TO COLORADO
NATIONAL MONUMENT. The stereoscopic pair of aerial photographs may
be viewed without optical aids by those accustomed to this
procedure, or by use of a simple double-lens stereoscope, such as
the folding ones used by the armed forces during and after World War
II. Geologic details may be identified by comparing photographs with
the geologic map, figure 8. If viewer is unable to see stereoscopic
pairs in three dimensions, looking at either photograph alone will
convey a good idea of the geologic structure. The monocline near top
of the photographs may be seen on the right-hand side of the highway
in figure 43. Photographs taken in 1937 by U.S. Soil Conservation
Service, hence, alinement of then unpaved Colorado Highway 340
differs from the paved present highway. (Fig. 33)]
At this point in our story it might be well to point out that the
folding and faulting of the rocks just described occurred when thousands
of feet of younger rocks covered the area. Additional folding and
faulting, drainage changes, and gradual removal of the overlying rocks
occurred during the remainder of the Tertiary and Quaternary Periods, as
will be discussed further.
Nearby Lava Flows[30]
Grand and Battlement Mesas, respectively east and northeast of the
Monument, are capped by several resistant thick flows of dark basaltic
lava. The molten rock welled up through fissures at the east end of
Grand Mesa and flowed westward and northwestward over the eroded surface
of Eocene rocks. Radiometric dating of a sample of the basalt indicated
an age of 9½ million years plus or minus half a million years, placing
the event in the Miocene Epoch of the Tertiary Period (fig. 61).
A small remnant of the lava on the crest of the Roan Cliffs just
southwest of the present town of Grand Valley indicates that the flows
crossed this part of the ancestral Colorado River Valley and may have
pushed the young stream westward.
The lava flows are about 800 feet thick on the eastern part of Grand
Mesa but are only about 200 feet thick above the western rim of the
mesa. As the ancestral Gunnison River is believed to be pre-Miocene in
age, it is not known whether or not the lava flows crossed the old river
valley and reached as far west as the Monument.
Ancestral Colorado River
During most of the Pliocene Epoch the ancestral Colorado River did not
flow past what is now Grand Junction; instead, it joined with the
ancestral Gunnison River about 10 miles southeast of the present city,
and the combined streams flowed southwestward across the slowly rising
Uncompahgre arch through what was later to be called Unaweep Canyon
(fig. 36). Southwest of the canyon, near the site of the present town of
Gateway, the ancestral Colorado River was joined by the combined flows
of the ancestral San Miguel River and the previously diverted ancestral
Dolores River, then it flowed northwestward to what is now the mainstem
of the Colorado River.
I have attempted to show my ideas of this ancient drainage system as it
may have existed in middle to late Pliocene time in figure 34. But the
stage was set for more spectacular drainage changes to follow.
Piracy on the High Plateaus
Rivers, like people, do not always choose their courses wisely. After a
few million years of downcutting through the soft sedimentary rocks,
mainly what is now called the Mancos Shale, the ancestral Colorado and
Gunnison Rivers found themselves cutting through the hard Proterozoic
rocks in a deep gorge athwart the slowly rising Uncompahgre arch, which
greatly slowed the downcutting power of the combined streams. Note in
figure 34_A_ that while the mighty ancestral Colorado and Gunnison
Rivers were in this frustrating predicament, a young upstart tributary
began cutting northward from what is now the mouth of the Dolores River
(fig. 34_D_). Although the combined main rivers could lower their
channel only very slowly because of the hard rock in Unaweep Canyon, the
tributary was able to cut downward and headward quite rapidly through
the soft Mancos Shale. It eventually cut around the northwestward
dipping Uncompahgre arch and headed southeastward toward the ancestral
Colorado River near the present site of Palisade.
Then occurred an act of piracy that put to shame the mightiest exploits
of Blackbeard and Captain Kidd. In latest Pliocene or earliest
Pleistocene time additional uplift of the Uncompahgre arch, an unusually
large flood, or both, caused the ancestral Colorado River to overflow
its banks and spill across a low shale divide into the headwaters of the
tributary. Some ponding may have preceded the spillover. With this
enormously increased supply of water, the tributary cut down rapidly
through the soft shale and captured the entire flow of the Colorado
River, but the ancestral Gunnison River still flowed through Unaweep
Canyon, as shown in figure 34_B_. Stream capture of this type is
appropriately called “piracy.”
But the piracy had not ended. Note in figure 34_B_ that the “new” river
sent out several tributaries, one of which headed for and, with the aid
of yet additional and greater uplift, soon captured the ancestral
Gunnison River, as shown in figure 34_C_. This second act of piracy left
Unaweep Canyon really “high and dry” except for small streams that
carried off what little water the canyon received from local rain and
snow. While these piracies were taking place, the Book Cliffs and the
edge of Grand Mesa gradually retreated away from the valley because of
erosion, and more of the Uncompahgre arch was uncovered.
The rising Uncompahgre arch, whose renewed uplifts in latest Pliocene or
earliest Pleistocene times played such an important role in the ultimate
abandonment of ancestral Unaweep Canyon, was asymmetric in that the
crest was not in the middle but was near the southwest side. Although
sharp, locally faulted monoclines are found on both sides of the arch,
including the part within the Monument, in general, the northeastern
flank has a rather gentle northeastward dip; whereas, the southwestern
flank of the arch also is bordered by normal faults of considerable
vertical displacement.[31] Thus, after abandonment, the minor drainage
in Unaweep Canyon continued to flow northeastward from a new divide near
the southwestern border, and ancestral West Creek began cutting
northeastward toward the new divide. The drainage pattern depicted in
figure 34_C_ differs slightly from my earlier interpretation and results
from additional fieldwork.[32]
[Illustration: PROBABLE DRAINAGE PATTERNS AND LAND FORMS NEAR THE
MONUMENT AT FOUR SUCCESSIVE STAGES OF DEVELOPMENT. Solid drainage
lines taken from the Moab and Grand Junction, Utah-Colorado,
topographic maps of the Army Map Service; dashed drainage lines are
my own ideas. _A_, just prior to piracy of ancestral Colorado River;
_B_, after piracy of ancestral Colorado River and just prior to
piracy of ancestral Gunnison River; _C_, abandonment of Unaweep
Canyon after renewed uplift of Uncompahgre arch and piracy of
ancestral Gunnison River; and _D_, present drainage pattern after
additional uplift and piracy of East Creek. Modified from Lohman
(1961, 1965a, 1965b). (Fig. 34)]
[Illustration: A, just prior to piracy of ancestral Colorado River]
[Illustration: B, after piracy of ancestral Colorado River and just
prior to piracy of ancestral Gunnison River]
[Illustration: C, abandonment of Unaweep Canyon after renewed uplift
of Uncompahgre arch and piracy of ancestral Gunnison River]
[Illustration: D, present drainage pattern after additional uplift
and piracy of East Creek.]
At the time of abandonment, ancestral Unaweep Canyon was a V-shaped
canyon resembling Glenwood Canyon just upstream from the city of
Glenwood Springs, Colorado. The reasons for its change in shape and
appearance to the beautiful U-shaped canyon we find today and the
profound effect the abandonment of Unaweep Canyon had on the deepening
of the Grand Valley and the canyons of the Monument will be brought out
in the section “Canyon Cutting.”
The Age of Man
Like the dinosaurs before them, a few of the Tertiary mammals were so
long on brawn and short on brains that they evolved into grotesque
monsters and overspecialized themselves into early extinction.
Fortunately, however, most of the mammals evolved more slowly and
moderately into the forms we find today.
One group—the anthropoid primates—began to think, so they developed
their brains rather than their brawn, particularly the Tertiary
ancestors of man. Few remains of these ancestors have been found in
Tertiary rocks, but many more have been discovered in rocks of the next
geologic period—the Quaternary. Thus, this period may properly be
regarded as the age of man, for man then began to dominate the Earth for
better or for worse.
The Quaternary—latest and shortest of the geologic periods—is divided
into the Pleistocene and Holocene (recent) Epochs (fig. 61).
The Ice Age
During the Pleistocene Epoch, all continents of the Northern Hemisphere
and some of the Southern Hemisphere were partly covered at least four
times by huge glaciers. Each glacial advance in Europe and North America
was ended by a warmer interval during which the glaciers melted and
retreated northward; then, vegetation and soil had time to become
re-established. Thus, the Pleistocene has properly been called the ice
age.
None of the continental glaciers reached the Monument or the Uncompahgre
Plateau, or arch, but small alpine glaciers grew in the high Rocky
Mountains to the east, sculpturing sharp-crested peaks and ridges and
forming beautiful valleys and lakes. Many of the beautiful lakes on
Grand Mesa were formed by glaciation, but some near the edges were
formed by landslides.
The increased streamflow from the greater precipitation and from melting
alpine glaciers in the Rockies, particularly during times of glacial
retreat, helped the Colorado River cut through the rocks faster, thus
assisting in the formation of Colorado National Monument as we see it
today. The river carried thousands of cubic miles of sediment to the
Gulf of California, including a lot of rock that once covered the
Monument, and the river is still actively at work on this immense
earthmoving project.
If the ancestral Colorado River carried sediment at about the same rate
as the present river since the building of Hoover Dam, it may have
carried about 3 cubic miles of sediment each century. Now most of the
rock debris is being dumped into Lake Powell—the new reservoir behind
Glen Canyon Dam. When this, Lake Mead, and other reservoirs ultimately
become filled with sediment, the Gulf of California will again be the
burial ground.
But other events during the Pleistocene also played a role in shaping
the area. The Uncompahgre arch was again uplifted and deformed in the
Pleistocene soon after the abandonment of Unaweep Canyon. This caused
added tilting of the strata and more bending and breaking along some of
the folds and faults in the Monument.
Capture of East Creek
East Creek, which drains the northeastern half of Unaweep Canyon, was
forced to change its course during the Pleistocene Epoch by another act
of piracy. After capture of the Gunnison River by the newly routed
Colorado River, East Creek joined the Gunnison by way of Cactus Park.
Then, a tributary of North East Creek headed southward and captured East
Creek, as shown in figure 34_D_.
Canyon Cutting
When the Colorado River was diverted into its new course through the
Grand Valley past the Monument, the stream channel seems to have been
only about 600 to 800 feet higher than it is today, but the present
divide in Unaweep Canyon is now about 2,500 feet higher than the
channel. The difference of 1,700 to 1,900 feet was caused by the
additional uplift of the Uncompahgre arch during the Pleistocene.
Thus, the Grand Valley and its tributary canyons, such as those of
Colorado National Monument, were cut since the abandonment of Unaweep
Canyon, probably mainly during the Quaternary Period. This suggests that
the cutting of the Monument’s canyons began only about 2 million years
ago, but that much of the canyon cutting occurred only a few hundred
thousand years ago. Indeed, the canyons are still slowly being deepened,
lengthened, and widened.
As you stand on any of the lookout points and gaze down into the canyons
of the Monument, you may well wonder how such immense chasms could have
been cut by such puny streams that are dry most of the time. The streams
flow only for short periods after heavy thundershowers or after rapid
melting of snow. If you are lucky enough to see them flow, you will
notice that the water is red or brown because of the suspended mud,
silt, and sand. If the flow is large, you may see or hear pebbles and
cobbles rolling along the bed. Accordingly, the streams and their
cutting tools are slowly deepening the channels. But, you may ask, how
does this account for such wide, broad-bottomed, cliff-walled canyons?
Such streams act mainly as storm sewers to carry off the rock debris
formed by other types of erosion.
When cutting first began, the Monument’s canyons were narrow, steep, and
V-shaped. When the top of the hard, dark Proterozoic rocks was reached,
however, downcutting slowed just as it had earlier in Unaweep Canyon.
While the streams were thus hung up, other erosional processes caused
the cliff walls to recede away from the streams, forming broad,
flat-bottomed, U-shaped canyons.
Recession of the cliffs away from the middle of the canyons probably was
caused partly by undercutting of the soft Chinle Formation by wind and
in places by streams. This allowed slabs of the overlying Wingate
Sandstone and younger rocks to break off and fall into the
canyons—eventually to break up and to be carted off as sand and mud by
streams.
But other processes are probably the ones chiefly responsible for the
present shape and width of the canyons. The summer sun heats the cliff
faces until they are hot to the touch, but in the present desert climate
of the Monument the rocks cool rapidly after sundown. Oftentimes the hot
cliff faces are chilled rapidly by summer thundershowers. Repeated
heating, cooling, wetting, and drying causes expansion and contraction
of the rocks so that thin layers break off and fall. This process goes
on slowly even in winter on sun-facing cliffs, but it does not occur on
the cliffs that face away from the winter sun.
Even more important, perhaps, is the alternate freezing at night and
thawing by day on sun-facing cliff faces during the winter. Water in
cracks near the cliff faces alternately freezes and melts, gradually
prying off slabs of rock. Canyon walls that are shaded from the sun most
of the winter, however, stay cold or frozen much of the winter; hence,
they are not subject to repeated heating and cooling or freezing and
thawing. Thus, you will notice that because of talus accumulation many
such canyon walls are sloping rather than vertical.
To illustrate the above conjectures concerning the cutting and shaping
of the canyons, let us consider several canyons that trend in different
directions. We have seen in figure 12 that the left side of
northeastward trending Red Canyon is a nearly vertical cliff that faces
the sun most of the winter; whereas, the right side, which is shaded
most of the winter, slopes gently enough to be climbed at many places.
The sides of Ute Canyon, which trends more nearly northward (fig. 52),
slope about equally, as would be expected. However, the west arm of the
Canyon, which trends slightly southeastward, has sides whose slopes
differ markedly (fig. 35).
This brings us to the remarkable transformation of the original V-shape
of Unaweep Canyon to the beautiful U-shape of the present canyon, which
is shown in figure 36. The abandonment of Unaweep Canyon discussed
earlier removed the gigantic storm sewer that for millions of years
carried off the products of vigorous erosion of the canyon walls by the
processes just described. Rock materials that now fall from the cliffs
of the inner gorge in hard Proterozoic rocks and that fall from the
overlying softer sedimentary rocks simply pile up at the foot of the
cliffs to form a canyon equally as U-shaped as those cut by glaciers in
the high mountains. Indeed, Unaweep Canyon has been mistaken for a
glacial canyon by many, including some geologists.
[Illustration: Petroglyph]
[Illustration: FALLEN ROCK, in west arm of Ute Canyon below
waterfall, from Fallen Rock Overlook. Note that the sun-facing left
side of canyon, containing the fallen block of Wingate Sandstone, is
a vertical cliff; whereas, the shaded right side can be readily
climbed. The right side contains a trail near the middle of the
picture, but it is hidden by vegetation. (Fig. 35)]
[Illustration: UNAWEEP CANYON, looking southwest from rim of inner
gorge cut in hard Proterozoic rocks, just to the right side of first
cattle guard on Divide Road, near middle of sec. 16, T. 14S., R. 100
W., about 5 miles northeast of drainage divide shown in figure
34_D_. Drainage divide is just around the corner to the right of the
most distant part of the canyon visible. Slope above vertical cliff
on right consists of Chinle Formation, Wingate Sandstone, and flat
crest of Entrada Sandstone (Kayenta Formation is absent). Paved road
in canyon is Colorado Highway 141. (Fig. 36)]
A Look into the Future
This ends the brief geologic story of Colorado National Monument, except
for a peek into the future, a description of trips through and around
the Monument, and a comparison with other Parks and Monuments on the
Plateau. The temporary nature of lakes, rivers, and even mountains has
been discussed—the Monument of today and the new course of the Colorado
River are no exceptions.
The Colorado River did not solve its problems by abandoning its
hard-rock course in Unaweep Canyon in favor of a soft-rock course
through Ruby and Westwater Canyons—it just postponed them. The river has
again cut down into its old nemesis—the hard Proterozoic rock—in Ruby
Canyon just within the Colorado border, in Westwater Canyon in Utah, and
the Gunnison River has reached the hard rock at its confluence with
Dominguez Creek, not far above Whitewater, as shown in figure 34_D_.
Thus, once again hard rock is slowing down old man river, and will slow
him down for a long time to come. Someday, Westwater and Ruby Canyons
will be deep gorges like Unaweep Canyon. Then it is quite possible that
another young tributary may sneak around the Uncompahgre arch some miles
northwest of these canyons and pirate the river into a new soft-rock
course.
By this time, the Monument will have changed appearance considerably.
Some of the canyons will have come together by eating away the ramparts
that separated them—just as the two entrances of Monument Canyon have
already done. But as the lower canyons thus eliminate themselves, the
headwaters will bite deeper into Piñon Mesa, so perhaps the Monument
will simply creep slowly southwestward. However, renewed uplift, more
volcanos, changes in climate, or other events could alter the picture.
Still, if the geologic clock ran as fast as the ones we use, the picture
of the Monument we see today would be on the screen only a small
fraction of a split second. But the geologic clock ticks on, slowly but
surely, and, someday, the Holocene Epoch in which we live will become
just another brief chapter in the long geologic history of the Earth.
[Illustration: Petroglyph]
How to See the Monument
How to see the monument depends in large part on how long you can stay,
but it depends also upon the direction you are travelling to or through
Grand Junction and Fruita, and on the mode of transportation. Moreover,
the Monument has four entrances—two main entrances from Fruita (West
Entrance) and Grand Junction (East Entrance), and two subordinate
entrances from the Glade Park area to the southwest.
Though by no means as well known as our large National Parks, Colorado
National Monument is more readily accessible than many. It is on two
transcontinental highways (U.S. 6 and 50), is the western terminus of
U.S. 24, and is on nearly completed Interstate 70, one of the most
scenic transcontinental Interstate Highways. Highway I-70 supersedes
many stretches of U.S. 6, 24, and 50, but the latter are still used in
parts of the Grand Valley and elsewhere. The Monument also is on the
main line of the Denver and Rio Grande Western Railroad, which still
maintains limited passenger service between Denver and Salt Lake City,
but this service may eventually be terminated. Grand Junction’s Walker
Field is served by several airlines, and both Grand Junction and Fruita
are served by busses.
Many people driving through the Grand Valley for the first time are
unaware of the Monument’s existence unless they happen to see it on a
roadmap or see road signs pointing toward it, but unfortunately the
signs are unevenly and poorly distributed. People entering Grand
Junction from the east on U.S. 6 and 24 or from the southeast on U.S. 50
are apt to see one or more of the signs—particularly when crossing Grand
Avenue on First or Fifth Streets. If they are heading westward and can
devote at least half a day, they may drive to the East Entrance, follow
Rim Rock Drive for 22 miles northwestward through the Monument, stop at
some or most of the scenic overlooks and the Visitor Center, leave via
the West Entrance, and proceed northwestward on U.S. 6 and 50 or better
yet on I-70. However, as will be described below, longer stops are much
more rewarding. Those driving eastward on I-70 may see the sign at the
Fruita interchange pointing southward toward the Monument—and may take
the above described quickie trip in reverse. Those heading northwestward
on I-70, however, may not be aware of the Monument until they see the
sign at the Fruita interchange; then, they may not have or take time to
double back southeastward through the Monument. If they do drive
southeastward through the Monument, however, they can return to Fruita
following a very scenic northwesterly route through The Redlands on
Broadway (Colo. Highway 340) and South Broadway, or they may take a
paved shortcut from near the East Entrance to South Broadway via South
Camp Road (p. 118). Drinking water and sanitary restrooms are available
in the headquarters area in the campgrounds and picnic grounds and
Visitor Center, and in the Devils Kitchen Picnic Area. Food is not
available in the Monument, so those planning to remain all day should
bring lunches.
I have conducted many groups through the Monument, always choosing to
travel northwestward from Grand Junction through The Redlands, just
northeast of the Monument, to the West Entrance, then returning
southeastward through the Monument.[33] On most days, taking the trip in
these directions affords good lighting for photographing most of the
scenic features. This and other routes are described in the next section
and are plainly labeled so that the visitor may start with any trip he
or she chooses. Regardless of how long you stay or which routes you
follow, it is advisable to be well supplied with color film.
Some of the view points and overlooks have displays or signs to help
interpret the scenic features, and more of these aids are added from
time to time.
There are three maps in this report (figs. 3, 8, 26); these maps will be
helpful to anyone touring the Monument. Figure 3 shows streams, highways
and roads, principal trails, named features, overlooks, and trip-guide
locations; figure 8 is a geologic map; and figure 26 shows localities
where most of the photographs were taken. In addition, topographic maps
of the Monument and adjacent areas by the U.S. Geological Survey, scale
1:24,000, are available from several sources and are a considerable aid
to visitors. In addition to cultural and drainage features, such maps
show the exact shape of the land by means of contour lines, which are
level lines that go in and out of canyons, around ridges, and so forth.
A special map of the Colorado National Monument quadrangle is available
also in a shaded relief edition, which gives a three dimensional effect
by proper shading of canyons and ridges. Both types of maps are for sale
at the Visitor Center, and these and adjacent quadrangles, such as the
Grand Junction, Fruita, Glade Park, and Island Mesa, are sold at several
engineering and stationery stores in Grand Junction and at the U.S.
Geological Survey’s Map Distribution Office, Building 41, Federal
Center, Denver, Colorado, 80225. The latter office and the Visitor
Center also sell copies of my “Geologic Map of the Grand Junction area,
Colorado,” published in 1963 as Miscellaneous Investigations Map I-404.
[Illustration: Petroglyph]
Trips Through and Around the Monument[34]
From Grand Junction through the Redlands to the West Entrance of the
Monument
STARTING POINT
[Mile-marker 1]
We will begin our trip in the southwestern part of Grand Junction at the
intersection of First Street and Grand Avenue, (this is also the
intersection of U.S. Highways 6 and 50 and Colorado Highway 340), by
following a sign on Highway 340 pointing westward toward the Monument.
After crossing a viaduct over the railroad yards and a bridge across the
Colorado River, we come to a traffic light and a sign pointing left
toward the Monument. The road to the left connects with Monument Road
which leads up No Thoroughfare Canyon to the East Entrance. However, we
will continue westward toward The Redlands.
REDLANDS CANAL
[Mile-marker 2]
Just beyond the stoplight we cross a bridge over the Redlands Power
Canal which carries 675 cubic feet per second (cfs, or ft³s⁻¹)[35] from
the Redlands Diversion Dam on the Gunnison River about 2½ miles south of
Grand Junction. A quarter of a mile northwest of the bridge, most of the
water falls to a lower powerplant that generates electricity for pumping
the remaining 50 cfs to three lift canals, which are used mainly for
irrigating peach orchards in the eastern part of The Redlands.
SOUTH BROADWAY
[Mile-marker 3]
After Colorado Highway 340 curves right it is known as Broadway—a paved
road serving much of The Redlands and connecting with the West Entrance
of the Monument. We will follow Broadway about 3 miles, passing low
outcrops and roadcuts of the Dakota Sandstone, some of which contain
coal beds and some of which are covered by a veneer of gravel laid down
by the river when the channel was higher. Then, at the first store and
filling station we turn southwest on another paved road known as South
Broadway.
SOUTH CAMP ROAD SIDE TRIP
[Mile-marker 4]
Just around the curve to the right is a T-intersection from which paved
South Camp Road leads south to a growing suburban area; and 2½ miles to
the southeast it connects with Monument Road at a point only half a mile
north of the East Entrance of the Monument.
Excellent views of the cliffs of dark Proterozoic rocks, the overlying
cliffs of the Wingate Sandstone, and the Redlands fault along the
northeastern border of the Monument are seen all along South Broadway,
but views from South Camp Road and several connecting roads to the
southwest are especially good. (See figs. 37 and 38.) As noted earlier,
the Redlands fault has a maximum vertical displacement of 700 or 800
feet, but dies out in scissors fashion at each end.
[Illustration: REDLANDS FAULT, looking west from South Camp Road
about one mile south of South Broadway. Fault here is nearly
vertical and normal, and lies between updragged Wingate Sandstone
and dark Proterozoic schist, gneiss, and granite. All or most of the
soft Chinle Formation has been squeezed out along the fault. Note
smooth erosion surface atop hard, dark rocks surmounted by slope of
red Chinle Formation and cliffs of Wingate Sandstone capped by
lowermost resistant beds of Kayenta Formation. (Fig. 37)]
_BRACHIOSAURUS_ MONUMENT
[Mile-marker 5]
As we continue westward on South Broadway, note on the right the
brightly colored mudstone and siltstone of the Brushy Basin Member of
the Morrison Formation strewn with large blocks of rusty-looking
sandstone from the Burro Canyon Formation, which caps the high ridge on
the right. Just above the deep cut on the right four-tenths of a mile
west of the intersection with South Camp Road is a bronze plaque set in
a masonry monument, whose lettering is easily readable in figure 39.
Many years after the excavation in 1900 (fig. 22), Elmer Riggs contacted
Al Look, of Grand Junction, in regard to the casting and erection of
this plaque. Al, Elmer, Ed Faber, and a few other citizens put up the
necessary funds and personally erected the plaque and monument. Somehow
or other, _Brachiosaurus_ was misspelled _Brachyosaurus_, as shown in
figure 39, but the intentions were good. Later I will call attention to
another similar monument commemorating the finding by Riggs of another
dinosaur skeleton.
[Illustration: CLOSEUP OF UPDRAGGED WINGATE SANDSTONE ALONG REDLANDS
FAULT, looking northwest from side road 1½ miles southwest of
intersection of South Camp Road and South Broadway. White “pimple”
atop cliff near left skyline is Liberty Cap, an erosional remnant of
the Wingate Sandstone, reachable via the Liberty Cap Trail (fig. 3;
and p. 108). Chinle Formation here was largely squeezed out along
the fault. (Fig. 38)]
WATCH TURNS
After a sharp turn to the north and another to the west, South Broadway
reaches the top of a hill just above the Elk’s Club and curves gently to
the right past sandstone lenses in the Salt Wash Member of the Morrison
Formation. A 610-foot-deep well at the house on the left formerly flowed
about 1½ gallons a minute from the Entrada and Wingate Sandstones.
[Illustration: BRONZE PLAQUE AND MONUMENT MARKING THE DISCOVERY OF
_BRACHIOSAURUS ALTITHORAX_ RIGGS, above roadcut on South Broadway
four-tenths of a mile west of South Camp Road. See also figure 22.
For discrepancy in spelling text. (Fig. 39)]
LEFT TURN
WATCH FOR BUFFALO
[Mile-marker 6]
Half a mile to the north, South Broadway turns sharply to the left even
though another paved road continues northward. Three-fourths of a mile
to the west, we turn northwestward parallel to the Monument boundary
fence for seven-tenths of a mile before turning north again. The 7-foot
chain-link fence just to the left of the road is the northeastern
boundary of the Monument and encloses the herd of buffalo. In the late
forties or early fifties a young bull challenged the older leader for
possession of the herd and gored and pounded the old bull so badly he
had to be shot by a ranger. During the furious battle 125 feet of this
strong steel fence was utterly demolished. It is reported that sometimes
an old bull simply takes one look at the young challenger and retreats
without a battle, but other lone or rogue bulls may temporarily or
permanently leave the herd for other reasons. Such outcasts are
dangerous and unpredictable. One bull kept a ranger “treed” for 4 hours
on a steep rock ledge in the broiling sun before moving on to a patch of
grass. Four of these critters delayed by one week my walking out a
stretch of the Redlands fault on their side of the fence. I decided that
a live geologist had advantages over a dead hero.
REDLANDS FAULT
WINGATE DRIVE SIDE TRIP
[Mile-marker 7]
Throughout most of its 6-mile length the Redlands fault is a vertical or
nearly vertical normal fault, but along and near this 0.7-mile stretch
it is a reverse fault that dips from 45° to 60° to the southwest, as
shown in figure 40 and in the cross section of figure 8. Good views of
the fault are seen all along the fence, but especially at points
one-tenth and four-tenths of a mile northwest of the first turn, the
second of which is shown in figure 40. Just after turning north on South
Broadway, let us turn west a few hundred feet on paved Wingate Drive to
see the northwest end of the Redlands fault, which passes through a col
to the left of updragged remnants of the thinned red Chinle Formation
and the Wingate Sandstone, as shown in figure 41.
[Illustration: REVERSE PART OF REDLANDS FAULT, looking N. 65° W.
from point on South Broadway along boundary fence. Most of Chinle
Formation has been squeezed out, but lower part of Wingate Sandstone
may be seen dipping about 45° southwestward beneath dark Proterozoic
rocks. Next pink band to right is Entrada Sandstone. Jumbled mass of
white sandstone slabs at right of photograph is part of Salt Wash
Member of Morrison Formation and is known locally as “White Rock”.
(Fig. 40)]
[Illustration: NORTHWEST END OF REDLANDS FAULT, passing through col
to left of updragged remnants of Chinle Formation and Wingate
Sandstone. Fault, which here is normal, ends against unbroken Lizard
Canyon monocline in next canyon to northwest. Looking west from
point just south of Wingate Drive a few hundred feet west of South
Broadway. (Fig. 41)]
MONUMENT CANYON TRAIL
About half a mile north of the last turn, South Broadway rejoins
Broadway (Colo. Highway 340) at a stop sign. After we turn left on
Broadway and reach the first curve, we get a nice view westward into
Monument Canyon, as shown in figure 42. The Park Service hopes to
establish a new trailhead at the bridge one-tenth of a mile west of the
curve, from which a new section of trail will follow the normally dry
wash southwestward to join the old Monument Canyon Trail. After we cross
the creek leaving the canyon, we pass a low hill of the Salt Wash Member
of the Morrison Formation on the left. Just beyond the hill, the dirt
road leading southwest to a farmhouse formerly was the beginning of the
Monument Canyon Trail (fig. 3). There is a new temporary trailhead a
quarter of a mile north, but it is hoped that a permanent one can be
built at the bridge about a quarter of a mile to the southeast, as noted
above. Hikers may see buffalo along this trail and should watch out for
outcast bulls.
[Illustration: LOOKING WEST INTO MONUMENT CANYON, from curve on
Broadway just northwest of end of South Broadway, showing
Independence Monument. This monument was seen in figure 6 and will
be seen again in figure 51. Redlands fault ends in this canyon;
Lizard Canyon monocline can be seen on extreme right. (Fig. 42)]
DRAINAGE DIVIDE
[Mile-marker 8]
About half a mile north of the farm road we reach the highest point on
Broadway (Colo. 340) at a drainage divide. Inasmuch as the three
Redlands Lift Canals end east of the divide, there is quite a contrast
between the lush irrigated lands east of the divide and the nearly
barren desert to the west, a view of which is shown in figure 43. To the
southwest of the divide is an excellent view of the
northeastward-dipping beds on the Lizard Canyon monocline. On the left
about a mile northwest of the divide we pass the other entrance of
Monument Canyon, then Lizard Canyon, and a switchback on Rim Rock Drive
ascending the ridge between Lizard and Fruita Canyons. The water well
beneath elevated tank on left is 650 feet deep and formerly flowed at
about half a gallon a minute from the Wingate Sandstone. Household needs
are obtained by pumping.
[Illustration: LOOKING WEST FROM DIVIDE ON BROADWAY 2 MILES EAST OF
WEST ENTRANCE TO MONUMENT. Monoclinal hill on right is Brushy Basin
Member of Morrison Formation capped by basal beds of Burro Canyon
Formation. Rocks at left middle are blocks of sandstone in the Salt
Wash Member of the Morrison. (Fig. 43)]
ROAD INTERSECTION
At the next intersection, Colorado Highway 340 turns right and continues
about 2½ miles to Fruita; the highway to the left reaches the West
Entrance of the Monument in a quarter of a mile. Before turning left
into the Monument, however, we will interrupt our description of the
trip by making a new start from Fruita for the benefit of people
travelling from this direction.
[Illustration: Bison]
From Fruita to the West Entrance of the Monument
MORRISON FORMATION
[Mile-marker 9]
From the Fruita interchange on I-70, the overpass leads north into the
town of Fruita, and Colorado Highway 340 leads south about 2½ miles to
the West Entrance of Colorado National Monument. One mile south we cross
the new bridge over the Colorado River; the old bridge formerly
connecting Fruita with the Monument may be seen half a mile upstream.
Just south of the new bridge we see sandstone on the left and green
shale on the right, both part of the Burro Canyon Formation. The high
hill on the left is made up of brightly colored siltstones and mudstones
of the Brushy Basin Member of the Morrison Formation capped by the basal
sandstone of the Burro Canyon Formation. On the southeast side of this
hill is another bronze plaque set in a masonry monument, similar to the
one at Riggs Hill (fig. 39), commemorating the discovery and removal in
1900 by Elmer S. Riggs of a skeleton of the immense dinosaur
_Apatosaurus excelcus_ Marsh. (See figure 23_B_). About 1¾ miles
northwest of the new bridge is the Fruita Paleontological area discussed
on page 50.
Just south of the hill, the highway curves gently to the left across a
relatively flat surface of the Morrison Formation. To the right may be
seen good exposures of the Entrada Sandstone, at the north end of which
curbstones were quarried from thin beds of the white Moab Member for use
in some of the parking areas along Rim Rock Drive. Some of the beds are
ripple marked[36] from wave action along ancient beaches or within
ancient lagoons. Some ripple-marked curbstones from this quarry may be
seen in the parking area at Red Canyon Overlook, and elsewhere in the
Monument.
As we approach the Monument we see that to the left the rock strata are
bent downward toward us along what geologists call a monocline (see
figs. 27 and 30), but to the right may be seen cliffs of dark
Proterozoic rocks surmounted by slopes of the red Chinle Formation and
cliffs of the buff Wingate Sandstone capped by the lowermost beds of the
resistant Kayenta Formation. The bent and broken rocks ahead are well
shown in figure 33.
About 1½ miles south of the Colorado River we reach the T-intersection
noted previously—at the end of the trip from Grand Junction through The
Redlands to the West Entrance of the Monument—and we are ready for our
trip through the Monument.
Through the Monument from West to East Entrances
WEST ENTRANCE
[Mile-marker 10]
After turning south on Rim Rock Drive from the intersection with
Colorado Highway 340 (Broadway), we cross the Monument’s northern
boundary and reach the checking station at the West Entrance, where a
small entry fee is charged during the summer. At the first left turn we
are in red beds of the Chinle Formation, then in sheared and broken beds
of the Wingate Sandstone along the Kodels Canyon fault. At the
easternmost loop of the road we may look southeastward across Lizard
Canyon to the Lizard Canyon monocline (fig. 30), and if we look down the
slope to the east we will see one of John Otto’s well-built trails that
formerly ascended the west side of Lizard Canyon to what is now the
campground, long before Rim Rock Drive was built. Do not try to stop at
the curve, however; play it safe, drive on, and park at Redlands View a
quarter of a mile west.
REDLANDS VIEW
By walking about 50 feet north of the turnout, we get an excellent view
to the west of the Kodels Canyon fault, as shown in figure 31. Just to
the north of the fault are the sheared and broken beds of the Wingate
Sandstone along the east end of this fault.
NEW EARTHFILL
Just beyond the turnout the road curves left through a cut in the
Wingate Sandstone and ascends the east side of Fruita Canyon. About a
quarter of a mile from the parking area we get a good view (fig. 44) to
the west of the new earthfill on Rim Rock Drive between the two tunnels.
The original fill was washed out in a few minutes on August 8, 1968, by
a cloudburst that dumped an estimated 4 inches of rain on the mesa west
of Fruita Canyon. A culvert beneath the road just north of the north
tunnel was wholly unable to cope with the resulting flood, part of which
plunged over the cliff but most of which roared southward through the
tunnel. According to the only known eyewitnesses—a couple from Ohio
whose car was stalled in 18 inches of swift water in the lower tunnel—an
estimated 4 feet of water flowing through the north tunnel soon
separated the two tunnels by a gaping chasm and flowed down where the
fill had been but moments earlier. They jockeyed their car back and
forth in the south tunnel and retraced the route back toward Fruita.
Later I viewed the chasm from the portal of the north tunnel and found
it awesome indeed.
[Illustration: NEW FILL ON RIM ROCK DRIVE BETWEEN TWO TUNNELS ON
WEST SIDE OF FRUITA CANYON, looking west from east side of canyon.
Previous fill was washed out by flash flood, as described in text.
(Fig. 44)]
[Illustration: Petroglyph]
The road remained closed for 1½ years until December 20, 1969, much to
the annoyance and discomfort of both visitors and Monument
personnel—particularly the latter. During the summer, the usual 16-mile
daily round trip to the post office in Fruita via the West Entrance was
increased to about 80 miles by way of the East Entrance. During the
school season, wives of Monument personnel took turns driving a station
wagon full of children on two daily round trips to the schools and post
office in Fruita. Note in figure 44, taken only 6½ years after the road
was reopened, that small gullies already have been cut in the lower half
of the new fill. Another local cloudburst could remove the new fill, but
let us hope this does not happen!
On the next curve to the east the road cuts entirely through the red
Chinle Formation, which here has a measured thickness of 103 feet.[37]
From the base of the Chinle to about the creek crossing the road cuts
expose the old Proterozoic metamorphic rocks, which here have a purple
hue.
BALANCED ROCK
[Mile-marker 11]
At the southernmost loop of the road is a parking area for viewing
Balanced Rock. The photograph for the frontispiece was taken from the
hillside near the foot of the monolith.
HISTORIC TRAILS VIEW
[Mile-marker 12]
After the road turns north, we again cross the entire Chinle Formation,
then penetrate the Wingate Sandstone through the two tunnels (turn on
your lights) shown on all the maps and in figures 33 and 44. Just beyond
the highest tunnel (turn off your lights) we reach Historic Trails View,
with a sign noting the early expeditions that traversed the area. West
from the parking area, but better yet by walking to the westernmost
curve, may be seen the northern part of the Black Ridge Trail.
[Illustration: FRUITA CANYON, looking northeast from point on Rim
Rock Drive above head of canyon. Dark Proterozoic rocks floor the
canyon, above which are the slopes of the red Chinle Formation and
the cliffs of Wingate Sandstone capped by the lower resistant beds
of the Kayenta Formation. Beyond the Grand Valley are the dark Book
Cliffs and the more distant, light-colored Roan Cliffs, which are
shown more clearly in figure 48. (Fig. 45)]
FRUITA CANYON VIEW
[Mile-marker 13]
This foot trail is part of the old stock trail over which sheep and
cattle once were driven down to the Grand Valley from Glade Park and
Piñon Mesa. The road then winds upward through a series of switchbacks
cut into the Kayenta Formation to Distant View and then to a parking
spot at the relatively new Fruita Canyon View, which affords a splendid
view of Fruita Canyon. Figure 45 was taken from a point about a tenth of
a mile to the east. On the right are housing facilities for Monument
personnel.
CAMPGROUND AND PICNIC AREA
[Mile-marker 14]
At the top of the hill just beyond the head of Fruita Canyon, two roads
turn left; the first makes several loops through the modern campground
and picnic area then returns to Rim Rock Drive; the second enters a
large parking lot at the Visitor Center. Let us take the first road,
then turn sharp to the left again just west of the Saddlehorn and
explore the camp and picnic areas, which are on a gently sloping mesa of
the Kayenta Formation dotted with piñon and juniper trees and bushes of
many kinds. The Saddlehorn is an erosional remnant of the Entrada
Sandstone. (See fig. 50.) The deluxe campground has both drive-through
and back-in campsites, modern restrooms, tables, piped water, and
grills. Two of the drive-through sites on the northernmost loop are
shown in figure 46.
[Illustration: CAMPSITES AT NORTH END OF CAMPGROUND, Grand Valley
and Book Cliffs beyond. (Fig. 46)]
A view of the picnic area and parking lot is shown in figure 47. During
the summer, evening slide talks are given by rangers at a small
amphitheater just north of the Saddlehorn and to the left of the view
shown in figure 47.
WINDOW ROCK
An interesting quarter-of-a-mile self-guiding Window Rock Nature Trail
leads from the northeast corner of the campground to Window Rock and
loops back past Book Cliffs View, which contains a table beneath a
ramada. Window Rock Trail connects with the scenic Canyon Rim Trail,
which leads southwestward to the Visitor Center. Views of Window Rock
and Monument Canyon from Canyon Rim Trail are shown in figures 48 and
49.
[Illustration: PICNIC AREA AND PARKING LOT, looking northeast from
top of the Saddlehorn. Large groups can be accommodated by making
advance reservations. Cliff of Wingate Sandstone on right across
Monument Canyon is part of Lizard Canyon monocline. (See fig. 29.)
(Fig. 47)]
VISITOR CENTER—MONUMENT HEADQUARTERS
After we return to Rim Rock Drive, a double left turn brings us to a
large parking lot. We are now at the Visitor Center and Monument
Headquarters, which is well worth a visit. In the front of the building
are modern restrooms and a drinking fountain. Inside the lobby may be
purchased film, slides, post cards, maps, booklets, and reports. A
narrated slide show and museum help materially in conveying just what
the Monument has to offer. I was pleased at being asked to contribute
several of the geologic exhibits, partly with the aid of former Survey
artist John R. Stacy. From the back door a path leads to a fenced
overlook for viewing an arm of Monument Canyon. The overlook also is the
beginning of Canyon Rim Trail which connects about half a mile to the
northeast with Window Rock Trail at Book Cliff View.
[Illustration: WINDOW ROCK, a window eroded along a vertical joint
near the top of the Wingate Sandstone. Telephoto view looking
northeast from Canyon Rim Trail. Note fenced overlook on Kayenta
Formation to left of window to keep people from crossing joint above
window, for someday the monolith to the right will fall, as did
Fallen Rock (fig. 35). Note light-colored Roan Cliffs of Green River
Formation beyond Book Cliffs. (Fig. 48)]
[Illustration: PIPE ORGAN, looking southeast across Monument Canyon
from Canyon Rim Trail, and Independence Monument to left beyond.
Photograph by Darrell Arnold, Grand Junction. (Fig. 49)]
GAP IN ROCK RECORD
[Mile-marker 15]
Half a mile southwest of the parking lot is one of the narrowest
stretches of Rim Rock Drive at the edge of a Wingate cliff that actually
overhangs. But do not worry, it is well protected by a rock wall. At the
head of the canyon is a large jumbled landslide of the Morrison
Formation that has covered the cliff of Entrada Sandstone. Along the
narrow stretch and just beyond the landslide are excellent views on the
right of the erosional unconformity between the eroded surface of the
Kayenta Formation and the overlying Slick Rock Member of the Entrada
Sandstone, a view of which is shown in figure 15 and a discussion of
which is given on pages 35 to 39.
PIPE ORGAN
[Mile-marker 16]
From the next parking area to the northeast at Pipe Organ Overlook we
may hike half a mile over Otto’s Trail to an overlook of the Pipe Organ;
a view of the Pipe Organ from the northwest is shown in figure 49. From
about the middle of this trail we may look to the northwest across the
canyon to the Visitor Center and the Saddlehorn (fig. 50).
DEPENDENCE VIEW
[Mile-marker 17]
At the next parking area at Independence View we see Independence
Monument (fig. 51) from quite a different angle than the photograph
shown in figure 6. This view clearly shows it to be a thin erosional
remnant of a narrow wall that once connected mesas to the northeast and
southwest and which separated the two entrances of Monument Canyon.
GRAND VIEW
[Mile-marker 18]
Grand View, six-tenths of a mile farther southeast, affords excellent
views of several features in and near Monument Canyon. A short improved
trail to the northeast leads to a sandstone ledge from which the
infrared photograph for the front cover was taken. The trail then veers
eastward to a fenced cliff-top viewpoint from which one may look nearly
straight down to a stretch of Monument Canyon Trail. You may see hikers
on the trail or buffalo in the canyon. The photograph for figure 6 was
taken from a point just north of the north end of the parking area.
MONUMENT CANYON VIEW
[Mile-marker 19]
Another 1⅓ miles takes us to the next parking area at Monument Canyon
View, from which one may walk a short distance to the northeast. The
photograph shown in figure 13 was taken from a point northeast of the
parking area.
From the head of Fruita Canyon to Monument Canyon View, Rim Rock Drive
is on a bench of the Kayenta Formation that separates the two lines of
cliffs. We must now leave this bench, however, because from near Coke
Ovens Overlook to beyond Artists Point the bench ceases to exist, and
the Entrada, Kayenta, and Wingate form virtually a single cliff.
Moreover, we must get up into the Morrison Formation in order to cross
the divide between Monument and Ute Canyons. For these reasons, in the
next three-quarters of a mile south of Monument Canyon View the road
cuts upward through the entire Entrada Sandstone. Just beyond the first
curve are quarries on the right from which curb and building stones were
cut by the Civilian Conservation Corps in the 1930’s for protecting
overlooks and narrow stretches of road. At the southwest end of this
stretch is another parking area at Coke Ovens Overlook, which provides
good views of the north side of the Coke Ovens.
COKE OVENS OVERLOOK
[Mile-marker 20]
The next parking area a quarter of a mile to the southwest is the
Monument Canyon Trailhead of the long trail to the mouth of Monument
Canyon and of a short trail to the Coke Ovens.
ARTISTS POINT
[Mile-marker 21]
Half a mile to the southeast takes us to a large parking area at Artists
Point, which offers a wide variety of scenic views. The best exposure of
the Summerville Formation in the entire area that I mapped[38] is on the
west side of the road, as shown in figure 20. A short trail leads down
to a fenced overlook for viewing the Coke Ovens to the north (fig. 11)
and Monument Canyon to the northeast.
[Illustration: VISITOR CENTER AND THE SADDLEHORN, looking northwest
across canyon from Otto’s Trail. Note thin-bedded bench of the
Kayenta Formation separating cliffs of the Entrada Sandstone above
the Wingate Sandstone below. The Saddlehorn is the remnant of the
Entrada at the extreme right. (Fig. 50)]
[Illustration: INDEPENDENCE MONUMENT, looking northeast from
Independence View. Note updragged block of Wingate Sandstone at
northwestern end of Redlands fault, just to the right of center. The
other side of this block is shown in figure 41. Grand Mesa forms
right skyline. (Fig. 51)]
HIGHLAND VIEW
DIVIDE
[Mile-marker 22]
The Summerville Formation is exposed on the right for about the next
half a mile. In the next three-quarters of a mile to Highland View the
roadcuts are in the sandstone ledges of the Salt Wash Member of the
Morrison Formation. Another half a mile through massive Salt Wash
sandstones takes us to the second highest point on Rim Rock Drive—the
divide between Monument and Ute Canyons, altitude 6,593 feet. From here
we may look far to the south across Glade Park to high Piñon Mesa—the
highest part of the Uncompahgre Plateau northwest of Unaweep Canyon,
where the altitude is about 9,500 feet.
LIBERTY CAP TRAILHEAD
[Mile-marker 23]
Halfway down the hill to the south is a parking area on the left at the
head of Liberty Cap Trail, which goes eastward about 6 miles to Liberty
Cap—a prominent conical point atop the Wingate cliff just west of the
mouth of Ute Canyon, which appears on the left skyline of figure 38.
From there, the trail descends about 2 miles to a gate in the boundary
fence at the mouth of Ute Canyon. The roads connecting the gate with
South Camp Road (fig. 3) were reported (1979) to be closed to foot
travel by private landowners, so hikers reaching this point must either
retrace their steps to the parking area at the head of the Liberty Cap
trail, or return by a primitive trail up main Ute Canyon, turn right up
the west arm of the canyon, and regain Rim Rock Drive by a short
switchback trail noted on page 109. However, the Park Service hopes that
in the future some sort of corridor can be established to connect the
trailhead with the nearby roads. Most of the “trail” up Ute Canyon is
the normally dry channel of the creek, so hikers should watch out for
flash floods. The round trip by Liberty Cap Trail alone is about 16
miles, and if the return trip is made by Ute Canyon the total distance
is about 13 miles. Accordingly, hikers should allow a full day and carry
food and water.
GLADE PARK ROAD
A quarter of a mile west of the Liberty Cap parking area in the west arm
of Ute Canyon is a junction with a gravel road that leads 5 miles south
to the Glade Park General Store and Post Office, where groceries, beer,
gasoline, and fishing and camping supplies are available. Glade Park
connects with scenic roads leading east, west, and south. Later, we will
cover in more detail a round trip from the intersection in Ute Canyon to
one near Cold Shivers Point, and another round trip from Glade Park
around the head of No Thoroughfare Canyon and back to Grand Junction via
the Little Park Road.
But to continue with the trip through the Monument—from the intersection
with the gravel road to Glade Park, Rim Rock Drive turns abruptly to the
southeast and follows the west arm of Ute Canyon for some 3 or 4 miles,
past many interesting points. For the next 1⅓ miles to the first
culvert, which crosses a large tributary, the roadcuts are in the
Summerville Formation and Entrada Sandstone. The photographs in figures
16 and 17 were taken looking north from the culvert and from just
northwest of the culvert, respectively.
FLOOD
[Mile-marker 24]
One day when my family and I were approaching the culvert from the west,
we heard a roar like an express train. Looking to the south we saw that
a severe thundershower was occurring on the headwaters in Glade Park, so
we raced ahead and parked east of the culvert just in time to see and
hear a 4-foot wall of red water come roaring down the tributary, rolling
boulders along as if they were basketballs. Unfortunately, we had no
time to ready or use a camera, so we simply raced down the road
embankment and through the trees and brush to the north in time to see
the flood plunge eastward over a 350-foot cliff of the Wingate Sandstone
to the canyon below. This illustrates the need for caution when
following or crossing “dry” washes in the desert in stormy weather or
when there are storms in the distance.
UPPER UTE CANYON VIEW
[Mile-marker 25]
About two-tenths of a mile northeast of the culvert is Upper Ute Canyon
View, which affords good views of the northeast cliff face of the west
arm of Ute Canyon.
FALLEN ROCK OVERLOOK
UTE CANYON TRAILHEAD
[Mile-marker 26]
For the next 7½ miles Rim Rock Drive is once again on a bench of the
Kayenta Formation between cliffs of the Entrada and Wingate Sandstones.
From Upper Ute Canyon View the road goes southeastward along the canyon
rim about three-tenths of a mile to a parking area. A short trail leads
down from the parking area to fenced Fallen Rock Overlook; the view
shown in figure 35 is from this point. As noted in the caption of figure
35, and on page 108, the Ute Canyon Trail zigzags down the slope from
the road a quarter of a mile southeast of the parking area, but there is
no parking area at the trailhead, so it is safer to park at Fallen Rock
Overlook and walk to the trailhead. The connection with this trail and
the Liberty Cap Trail also is discussed on page 108. On one hike down
this trail we saw two elk, which is a rare sight at such a low altitude,
for they generally stay on or near Piñon Mesa.
UTE CANYON
[Mile-marker 27]
About a mile to the southeast, just beyond the steep dropoff on the
left, there is room to park, walk a short distance through the trees to
the east, and observe a fine view of main Ute Canyon, as shown in figure
52. Just beyond on our right are the cliffs of the mottled
salmon-and-white Slick Rock Member overlain by the all white Moab
Member, as shown in figure 18 and described in the accompanying text.
Half a mile southeast, where the road makes a gentle U-turn and
continues northeastward, we reach the highest point on Rim Rock Drive at
an altitude of about 6,640 feet. Note that the piñon and juniper are
larger, and the bushes are larger and greener at this altitude, for the
average precipitation increases as we go higher.
LOWER UTE CANYON VIEW
[Mile-marker 28]
About a mile northeast of the highest point on the road is a large
parking area on the left, from which a short, shaded trail leads to a
fenced overlook called Lower Ute Canyon View, which faces the northwest
arm of Ute Canyon across the main canyon.
[Illustration: UTE CANYON, looking northeast from point described in
text. Note grass-covered alluvium in distant part of canyon floor.
(Fig. 52)]
RED CANYON OVERLOOK
[Mile-marker 29]
About half a mile beyond this parking area, we reach a small parking
area at Red Canyon Overlook, from which the photograph shown in figure
12 was taken. The dark green bush of Mormon Tea in the right foreground
of figure 12 is one of the largest I have seen in the Monument. The
reasons for the differences between the left and right walls of the
canyon are discussed on pages 79 and 80. The ripple-marked curbstones of
white sandstone in the parking area were quarried from the Moab Member
of the Entrada Sandstone northwest of Fruita Canyon, as noted on page
96.
DS ROAD
COLD SHIVERS POINT
[Mile-marker 30]
Another 2½ miles around the south rim of Red Canyon and the head of
Columbus Canyon takes us to the junction with the paved county road
known as the DS Road, which leads south and southwest to Glade Park and
to the head of No Thoroughfare Canyon. This important intersection will
be included in trips through Glade Park and around the head of No
Thoroughfare Canyon, so it will be discussed later. Meanwhile, we will
continue our trip eastward from this intersection. About a third of a
mile to the northeast is a large parking area, with a path leading to a
fenced overlook at the rim of Columbus Canyon for viewing Cold Shivers
Point—perhaps the most aptly titled feature in the Monument (fig. 53). A
primitive path leads from the overlook to the toadstool-shaped platform
at upper right, on which some visitors dare to stand, but not me. When
the old, steep Serpents Trail was the only route for autos to ascend
from the East Entrance, barrels of water were kept at this parking area
to quench the thirst of boiling radiators.
HEAD OF SERPENTS TRAIL
[Mile-marker 31]
After leaving the parking area, the downgrade on the Kayenta Formation
begins to steepen to the northeast until it becomes advisable to shift
into second gear. In about half a mile we descend a series of steep
switchbacks cut into the Wingate Sandstone on the steepening Ladder
Creek monocline (figs. 8, 29), and we reach the present upper end of the
old Serpents Trail (fig. 54), which is now an interesting foot trail. As
noted earlier, it is convenient to hike down this steep 2½-mile trail
and to have one member of the party drive ahead and await the hikers at
the parking area in the Devils Kitchen Picnic Area, near the foot of the
trail. One of many rewarding views seen during the hike is shown in
figure 55, another was seen in figure 10.
[Illustration: COLD SHIVERS POINT, looking north from fenced
overlook on east edge of Columbus Canyon. Named feature is
toadstool-shaped rock at upper right. Note dark Proterozoic rocks in
canyon bottom. (Fig. 53)]
[Illustration: TOP OF OLD SERPENTS TRAIL, looking northeast from
switchbacks above tunnel. Top of trail is seen at sign on lower
right. Grand Mesa forms right skyline. (Fig. 54)]
[Illustration: LOOKING NORTHEAST FROM OLD SERPENTS TRAIL, before
1950 when the trail was still used by autos and trucks. One of John
Otto’s old foot trails joins the old road at lower middle. Although
no thick lenses of sandstone appear in the Salt Wash Member of the
Morrison Formation in figure 21, in this view a lens about 50 feet
thick begins just around the corner near the base of the high bluff
across No Thoroughfare Canyon and is seen extending as far to the
left as the normally dry wash that drains the canyon. When water
flows down the wash after thundershowers (see p. 118) or from
melting snow, the sandstone lens takes in water (recharge) which
moves slowly down the dip of the lens to the northeast and supplies
several artesian wells. In turn, the light band of the Entrada
Sandstone beneath the cottonwood trees at the right middle and the
dark patch of Wingate Sandstone at the extreme lower right are
recharged in like manner, and they supply water to artesian wells to
the northeast. As the older and deeper sandstones on the right take
in water at higher altitudes, the water in them is under greater
artesian head when tapped by wells. If you think you see covered
wagons near the middle of the photograph arranged in a circle for
defense against attack by Indians, you are correct—a Western movie
was about to be filmed. (Fig. 55)]
[Illustration: Petroglyph]
[Illustration: SOUTH PORTAL OF TUNNEL THROUGH WINGATE SANDSTONE, on
west side of No Thoroughfare Canyon above East Entrance. (Fig. 56)]
FOOT OF SERPENTS TRAIL
Just beyond the lowest switchback shown in figure 54, we penetrate the
Wingate Sandstone through a tunnel, the south portal of which is shown
in figure 56. After we drive through a deep cut in the Wingate Sandstone
just south of the tunnel, we cross the entire red Chinle Formation, then
descend a series of switchbacks in old Proterozoic rocks. The Chinle
Formation is crossed again near the foot of the hill, where it is about
80 feet thick,[39] then we recross the Wingate Sandstone and Kayenta
Formation to the parking area in the Devils Kitchen Picnic Area, near
the foot of the old Serpents Trail.
DEVILS KITCHEN
[Mile-marker 32]
An improved marked trail leads southward from parking area at the foot
of the Serpents Trail, crosses No Thoroughfare Canyon, and continues as
an unimproved trail to the Devils Kitchen, a view of which is shown in
figure 57. The petroglyphs shown in figure 4 are northeast of this
parking area. Those interested in seeing them should inquire at the
ranger station or checking station at the East Entrance.
EAST ENTRANCE
Just beyond the parking area, near the foot of the old Serpents Trail, a
road turns left to a larger parking area for the Devils Kitchen Picnic
Area, where covered tables, grills, and water are available. Just beyond
we pass the checking station and housing facilities for Monument
personnel at the East Entrance of the Monument. During the summer, fees
are collected at this checking station from persons entering the
Monument. A well just east of the housing area obtains water from the
Entrada Sandstone to supply the houses and picnic area.
[Illustration: Petroglyph]
[Illustration: DEVILS KITCHEN, looking north from ridge in middle of
No Thoroughfare Canyon. An erosional remnant of the Wingate
Sandstone capped by the lowermost sandstone of the Kayenta
Formation. Photograph by T. F. Giles, U.S. Geological Survey. (Fig.
57)]
From the East Entrance to Grand Junction
SOUTH CAMP ROAD SHORTCUT
Three fourths of a mile beyond the checking station, South Camp Road
turns left and joins South Broadway 2½ miles to the northwest. This
provides a fine shortcut for persons desirous of travelling back
northwestward through The Redlands to regain the West Entrance of the
Monument. The intersection of South Camp Road and South Broadway, a key
point on the trip “From Grand Junction through The Redlands to the West
Entrance of the Monument,” is noted on page 89.
But let us continue our 3-mile return trip to Grand Junction, in order
to point out several things of interest along Monument Road in the lower
part of No Thoroughfare Canyon. As the canyon narrows just beyond the
road intersection, we see on both sides colorful badlands of the
Morrison Formation capped by the rusty looking basal sandstones of the
Burro Canyon Formation. Behind the building on the right just before the
road curves to the left is an artesian well 575 feet deep that taps both
the Entrada Sandstone and a sandstone lens in the Morrison
Formation[40].
GAP IN ROCK RECORD
[Mile-marker 33]
About 2½ miles below the checking station, we pass on the left the basal
sandstone of the Burro Canyon Formation resting on the Morrison
Formation, as shown in the lower left of figure 24. Just beyond we may
look up the hill to the left and see the 40-foot basal conglomerate of
the Dakota Sandstone resting unconformably on an old erosion surface
atop the Burro Canyon Formation.
FLOOD DAMAGE
Just before we reach the T-intersection with the eastern segment of
South Broadway we may still see on the right some of the destruction
caused by a devastating flood that roared down No Thoroughfare and other
canyons on September 7, 1978, as a result of what was termed the worst
cloudburst to hit Glade Park, the Monument, and the Grand Valley since
1958. A house on the flood plain just above the bridge was badly damaged
and was filled with 4 feet of mud, and the Monument Road bridge across
No Thoroughfare Canyon nearest the intersection was washed out,
necessitating the rerouting of traffic to and from the East Entrance of
the Monument. Moral—never build a house or even pitch a tent in a dry
wash or arroyo in desert regions! Incidentally, indirect measurements by
engineers of the U.S. Geological Survey indicated a discharge of 9,290
cfs just above the washed out bridge in No Thoroughfare Canyon, and
2,980 cfs in Red Canyon beneath the Broadway bridge.
SOUTH BROADWAY
Inasmuch as the bridge on Monument Road has long since been rebuilt, we
will cross it, turn right on South Broadway at the T-intersection, cross
the Redlands Power Canal (p. 88), and join Colorado Highway 340 at the
traffic light; thus, we complete a round trip “From Grand Junction
through The Redlands to the West Entrance of the Monument,” “Through the
Monument from West to East Entrances,” and “From the East Entrance to
Grand Junction.”
Through Glade Park from the Northwest Arm of Ute Canyon to Columbus
Canyon
GLADE PARK ROAD
[Mile-marker 34]
A very pleasant 11-mile drive through Glade Park may be made from the
intersection where Rim Rock Drive crosses the northwest arm of Ute
Canyon (p. 108) to the intersection with the same drive on the rim of
Columbus Canyon a quarter of a mile southwest of Cold Shivers Point (p.
120). The name Glade Park refers not only to the Store and Post Office
mentioned earlier, but also to a nearly flat farming and ranching area
south of the Monument—an area entirely different from the Monument or
The Redlands. Most of the cultivated part of Glade Park is underlain by
nearly flat lying Entrada Sandstone which was weathered to a sandy soil,
but a few areas are underlain by the Morrison Formation. This drive
should appeal particularly to people spending from a few days to a week
or more in the campground. For the more adventuresome, other interesting
roads join Glade Park from several directions, as noted below.
After leaving Rim Rock Drive at Ute Canyon, on a good gravelled road, we
traverse attractive, hilly, wooded country generally southward for about
a mile and climb some 300 feet to a flat area covered mainly by
sagebrush and grass. About 3 miles south of the intersection, we see on
the left the leached white outcrops of the Entrada Sandstone shown in
figure 19.
GLADE PARK
[Mile-marker 35]
Another 2 miles takes us to the Glade Park Store and Post Office at a
four-way intersection.
An improved, gravelled road leads westward through pleasant country some
20 miles to the Utah State line, beyond which an unimproved road leads
either to the Colorado or the Dolores Rivers. Future planning calls for
improving the Utah stretch of this road and for building a bridge across
either the Colorado or Dolores Rivers to connect with scenic Utah
Highway 128. If and when completed, this would afford a very scenic
shortcut from Moab, Utah, to Grand Junction via the Little Park Road (to
be described).
South from the four-way intersection an improved gravelled road takes us
through wooded country, past lakes and campgrounds, to the summit of
Piñon Mesa, as noted earlier.
GLADE PARK FAULT
[Mile-marker 36]
Also, from the intersection a paved county road known as DS (south) Road
leads eastward then northeastward through farming and ranching country 6
miles to the intersection with Rim Rock Drive near Cold Shivers Point.
Three-fourths of a mile east of the Glade Park Store and Post Office the
road crosses the Glade Park fault (fig. 8) along which the Morrison and
Summerville Formations on the right have dropped down with respect to
the Entrada Sandstone on the left. Here, the Entrada also has been
leached to white.
LITTLE PARK ROAD
[Mile-marker 37]
At 1½ miles east of the Glade Park Store and Post Office is the
intersection with the improved gravelled Little Park Road, which will be
described later. At 2¾ miles beyond this intersection, the DS Road
leaves the Entrada Sandstone and is on a wooded stretch of the Kayenta
Formation the remaining 2 miles to Rim Rock Drive. The last one-tenth of
a mile is crooked and steep, so please slow down before reaching the
stop sign at the intersection. Some years ago the brakes on a pickup
truck failed as the driver approached the stop sign, but he was lucky
enough to jump out at the top of the cliff just before the truck plunged
to the bottom of Columbus Canyon.
From Glade Park to Grand Junction Via the Little Park Road
GLADE PARK FAULT
[Mile-marker 38]
From the intersection 1½ miles east of the Glade Park Store and Post
Office, let us turn southeast on the recently improved and gravelled
Little Park Road around the head of No Thoroughfare Canyon, which was
added to the Monument in 1978 (fig. 3). From the intersection it is
about 14 miles to Grand Junction by this route. In half a mile we reach
the new boundary of the Monument at a minor drainage divide, and as we
start down a steep hill beyond we may park on the right and look
southeastward across No Thoroughfare Canyon along the Glade Park fault
(fig. 58) which has produced the fishtail shape of the head of the
canyon, as shown in figures 8 and 59. A different view of the fault and
canyon head is shown by the stereoscopic pair of aerial photographs in
figure 59.
The Little Park Road closely follows the new Monument boundary around
the south end of No Thoroughfare Canyon, either on the Kayenta Formation
or Entrada Sandstone, and affords good views into the canyon from
several places. East of the southeast arm of the canyon, the road leaves
the boundary and goes northeastward about 4 miles to the end of the
improved part of the road, but the unimproved part is good, and the
lower 5 miles is paved. On my geologic maps[41] of the area, I called
this road by its older name—the Jacobs Ladder Road.
LADDER AND ROUGH CANYONS
[Mile-marker 39]
About a quarter of a mile from the end of the improved stretch, one may
turn right on two tire tracks, travel about a quarter of a mile farther,
and park near the junction of Rough and Ladder Canyons, where
interesting geology is reachable by short walks up Ladder Canyon or down
Rough Canyon. About a mile up Ladder Canyon is an interesting abandoned
mica mine.[42]
[Illustration: GLADE PARK FAULT VIEWED FROM THE GROUND, crossing
head of No Thoroughfare Canyon. Looking southeast from Little Park
Road just southeast of new Monument boundary. Fault passes just to
right of white cliff of Wingate Sandstone near bottom of photograph
through notch in east wall of canyon. Note that surface to right
(south) of fault has dropped about 50 feet below left side. Grand
Mesa forms skyline. (Fig. 58)]
From the left side of the road, about 9 miles northeast of our starting
point, we see the view shown in figure 60. About 2 miles farther north,
Little Park Road is paved through a suburban housing development all the
way to The Redlands; there, we may turn right, cross the Gunnison River,
and reach U.S. Highway 50; or we may turn left through Rosevale and
reach Colorado Highway 340.
[Illustration: GLADE PARK FAULT VIEWED FROM THE AIR, crossing head
of No Thoroughfare Canyon from left to right. Land south of the
fault was dropped some 50 feet below that on the north side.
Primitive road around head of canyon has been improved and realined
since photographs were taken. The stereoscopic pair of aerial
photographs may be viewed without optical aids by those accustomed
to this procedure or by use of a simple double lens stereoscope,
such as the folding ones used by the armed forces during and after
World War II. Compare with the geologic map, figure 8. Photographs
taken in 1937 by U.S. Soil Conservation Service. (Fig. 59)]
[Illustration: LADDER CREEK MONOCLINE AND REDLANDS FAULT, looking
northwest from lookout point near Little Park Road. Telephoto view
of left half of this scene is shown in figure 29; photograph of
Morrison Formation shown in figure 21 was taken from point about a
mile farther north. (Fig. 60)]
Résumé of Geologic History and Relation to Other National Parks and
Monuments in the Colorado Plateau
In the geologic story of the Monument discussed on pages 17 to 94, the
geologic processes and events leading to the Monument of today were told
in the order in which they occurred; therefore, the details of the
geologic history have already been covered. Having finished this story
and the trips through and around the Monument, let us see how the
colorful canyons, cliffs, and other erosion forms fit into the bigger
scheme of things—the geologic age and events of the Earth as a whole, as
depicted in figure 61. As shown in figure 7, the rock strata still
preserved in the Monument range in age from Proterozoic to Cretaceous,
or from about 1,500 million to 100 million years old—a span of about
1,400 million years. This seems an incredibly long time, until one
compares figures 7 and 61, and notes that the Earth is some 4,500
million years old, and that the rock pile in the Monument is only about
a third the age of the Earth as a whole.
[Illustration: GEOLOGIC TIME SPIRAL, showing the sequence, names,
and ages of the geologic periods and epochs, and the evolution of
plant and animal life on land and in the sea. The primitive animals
that evolved in the sea during the vast Archean and Proterozoic Eons
left few traces in the rocks because they had not developed hard
parts, such as shells, but hard-shell or skeletal parts became
abundant during and after the Cambrian Period. This drawing was made
when the Geological Survey and most others used the term Precambrian
to embrace what is now included in the Archean and Proterozoic Eons.
The end of the Archean Eon and beginning of the Proterozoic Eon has
been placed at about 2,500 million years ago. Also, because of more
recent radiometric dating, the ages of the boundaries between some
of the geologic periods and epochs have been changed slightly. Of
most concern to this report, the boundary between the Pliocene and
Pleistocene Epochs has been changed from 3 million to 2 million
years. Drawn by John R. Stacy originally for inclusion in a report
by Newman (1976). (Fig. 61)]
The Age of the Earth
The Earth is very old—4.5 billion years or more according to recent
estimates. Most of the evidence for an ancient Earth is contained in
the rocks that form the Earth’s crust. The rock layers themselves—like
pages in a long and complicated history—record the surface-shaping
events of the past, and buried within them are traces of life—the
plants and animals that evolved from organic structures that existed
perhaps 3 billion years ago.
Also contained in rocks once molten are radioactive elements whose
isotopes provide Earth scientists with an atomic clock. Within these
rocks, “parent” isotopes decay at a predictable rate to form
“daughter” isotopes. By determining the relative amounts of parent and
daughter isotopes, the age of these rocks can be calculated.
Thus, the results of studies of rock layers (stratigraphy), and of
fossils (paleontology), coupled with the ages of certain rocks as
measured by atomic clocks (geochronology), attest to a very old Earth!
But this is not the whole story. As indicated earlier, younger Mesozoic
and Tertiary rocks more than 1 mile thick that once covered the area
have been carried away by erosion, and, if we include these, the span is
increased by another 50 million years or so.
If we consider the geologic formations that make up the national parks
(N.P.), national monuments (N.M.) (excluding small historical or
archaeological ones), Monument Valley, San Rafael Swell, and Glen Canyon
National Recreation Area, all in the Colorado Plateau, it becomes
apparent that certain formations or groups of formations play starring
roles in some parks or monuments, some play supporting roles, and in a
few places the entire cast of rocks gets about equal billing. Let us
compare them and see how and where they fit into the “Geologic Time
Spiral” (fig. 61).
Dinosaur N.M. and Colorado N.M., with exposed rocks ranging in age from
Proterozoic to Cretaceous, cover the greatest time spans (nearly 2
billion years), but most of the rocks are missing at Colorado N.M., as
noted below. Dinosaur N.M. has one unit—the Jurassic Morrison
Formation—in the starring role, for this unit contains the many dinosaur
fossils that give the monument its name and fame, although there are
several older units in supporting roles. Grand Canyon N.P. is next, with
rocks ranging in age from Proterozoic through Permian (excluding the
Quaternary lava flows), but here is truly a team effort, for the entire
cast gets about equal billing. Canyonlands N.P. stands third in this
category, with rocks ranging from Pennsylvanian to Jurassic, but we
would have to give top billing to the Permian Cedar Mesa Sandstone
Member of the Cutler Formation, from which The Needles, The Grabens, and
most of the arches were sculptured. The Triassic Wingate Sandstone and
the Triassic(?) Kayenta Formation get second billing for their roles in
forming and preserving Island in the Sky and other high mesas. Now let
us consider other areas with only one or few players in the cast,
beginning at the bottom of the time spiral. Black Canyon of the Gunnison
N.M., cut entirely in rocks of early Proterozoic age with only a veneer
of much younger rocks, obviously has but one star in its cast. Colorado
N.M. contains rocks ranging from Proterozoic to Cretaceous (equal to
Dinosaur in this respect), but Colorado is unique in that all rocks of
the long Paleozoic Era and some others are missing from the cast. Of
those that remain, the Triassic Wingate and the Triassic(?) Kayenta are
the stars, with strong support from the Jurassic Entrada Sandstone and
from the Proterozoic rocks, which floor the U-shaped canyons.
All the bridges in Natural Bridges N.M. were carved from the Permian
Cedar Mesa Sandstone Member of the Cutler Formation, also one of the
stars in Canyonlands N.P. In Canyon de Chelly (pronounced dee shay) N.M.
and Monument Valley (neither a national park nor a national monument, as
it is owned and administered by the Navajo Tribe), the De Chelly
Sandstone Member of the Cutler Formation—a Permian member younger than
the Cedar Mesa—plays the starring role.
Wupatki N.M. near Flagstaff, Ariz., stars the Triassic Moenkopi
Formation. Petrified Forest N.P. (which now includes part of the Painted
Desert) has but one star—the Triassic Chinle Formation, in which are
found many petrified logs and stumps of ancient trees. The
Triassic-Jurassic Glen Canyon Group, which includes the Triassic Wingate
Sandstone, the Triassic(?) Kayenta Formation, and the
Triassic(?)-Jurassic Navajo Sandstone, receives top billing in recently
enlarged Capitol Reef N.P., but the Triassic Moenkopi and Chinle
Formations enjoy supporting roles.
The Triassic(?)-Jurassic Navajo Sandstone, which has a supporting role
in Arches N.P., is the undisputed star of Zion N.P., Rainbow Bridge
N.M., and Glen Canyon National Recreation Area. The Navajo also forms
the impressive reef at the east edge of the beautiful San Rafael Swell,
a dome, or closed anticline, now crossed by Highway I-70 between Green
River and Fremont Junction, Utah.
As we journey upward in the time spiral (fig. 61), we come to the
Jurassic Entrada Sandstone, which stars in Arches N.P., with help from
the underlying Navajo Sandstone, and a supporting cast of both older and
younger rocks. The Entrada also forms the grotesque erosion forms called
“hoodoos and goblins” in Goblin Valley State Park, north of Hanksville,
Utah.
Moving ever upward in the spiral, we come to the Cretaceous—the age of
the starring Mesaverde Group, in which the caves of Mesaverde N.P. were
formed, and which now house beautifully preserved ruins once occupied by
the Anasazi (the ancient people who once dwelt in many parts of the
Plateau).
This brings us up to the Tertiary Period, during the early part of which
the pink limestones and shales of the Paleocene and Eocene Wasatch
Formation were laid down in inland basins. Beautifully sculptured
cliffs, pinnacles, and caves of the Wasatch star in Bryce Canyon N.P.
and in nearby Cedar Breaks N.M. This concludes our climb up the time
spiral, except for Quaternary volcanos and some older volcanic features
at Sunset Crater N.M., near Flagstaff, Ariz.
Thus, one way or another, many rock units formed during the last couple
of billion years have performed on the stage of the Colorado Plateau
and, hamlike, still lurk in the wings eagerly awaiting your applause to
recall them to the footlights. Do not let them down—visit and enjoy the
national parks and monuments of the Plateau, for they probably are the
greatest collection of scenic wonderlands in the world.
Acknowledgments
I am grateful to many friends and colleagues not only for help on the
present report, but also for help on the two preceding reports which
made this one possible. I refer to my Professional Paper 451,[43] which
supplied the detailed geologic data and to the first popular-style
booklet.[44] First of all, I must acknowledge the great help rendered by
members of my family—my eldest son Bill for serving as my unpaid field
assistant for most of the detailed mapping of the Grand Junction area,
and my two younger sons Terry and Bob for similar services during the
last phases of the fieldwork. I am especially indebted to my wife Ruth
for material assistance in all the fieldwork, including the road logging
and the color photography for the present report.
I am grateful to several colleagues of the Geological Survey and
National Park Service for help, data, or reviews of all three reports
noted, and to members of my family for reviewing both popular-style
reports.
For reviewing the present report I am especially indebted to David V.
Harris, Emeritus Professor of Geology, Colorado State University; Harry
A. Tourtelot, Geologist, U.S. Geological Survey, for reviewing both
popular-style reports and contributing petrographic studies to the
detailed report; and to my wife, Ruth.
The comments and criticisms of all reviewers were carefully considered
and most were adopted, but in some places I have preferred to state
things in my own way, and have included topics that seemingly were of
more interest to me than to some of the reviewers. The responsibility
for the form and content of this report thus remains mine.
References
Listed below in alphabetical order are the reports referred to in this
report. In the next section are listed reports for additional reading,
which I hope will be of general interest to most readers of this report.
Beckwith, E. G., 1854, Report of explorations for a route for the
Pacific Railroad: U.S. Pacific R.R. Explor., v. 2, 128 p.
Cashion, W. B., 1973, Geologic and structure map of the Grand Junction
Quadrangle, Colorado: U.S. Geol. Survey Misc. Inv. Ser. Map
I-736 [reprinted 1979].
Cater, F. W., 1970, Geology of the salt anticline region in
southwestern Colorado: U.S. Geol. Survey Prof. Paper 637, 80
p.
Colorado State Planning Commission, 1959, Colorado Year Book,
1956-1958: Denver, 871 p.
Dellenbaugh, F. S., 1902, The romance of the Colorado River: New York,
G. P. Putnam’s Sons, 399 p. [reprinted 1962 by Rio Grande
Press, Chicago, Ill.]
Hamilton, D. L., 1956, Colorado National Monument, past and present:
Intermountain Assoc. Petroleum Geologists, 7th Ann. Field
Conf. Guidebook, p. 48-49.
Hansen, W. R., 1969, The geologic story of the Uinta Mountains [with
graphics by John R. Stacy]: U.S. Geol. Survey Bull. 1291, 144
p.
Hayden, F. V., 1877, Report of progress for the year 1875: U.S. Geol.
and Geog. Survey Terr., embracing Colorado and parts of
adjacent territories, 827 p., 70 pls., 67 figs.
Hunt, C. B., 1969, Geologic history of the Colorado River, _in_ The
Colorado River region and John Wesley Powell: U.S. Geol.
Survey Prof. Paper 669, p. I-IV, 59-130.
Jennings, J. D., 1970, Canyonlands—aborigines: Naturalist, v. 21,
Summer, Spec. Issue 2, p. 10-15.
Lohman, S. W., 1960, Geology of west-central Colorado, _in_ Guide to
the geology of Colorado: Geol. Soc. American, Rocky Mtn.
Assoc. Geologists, and Colorado Sci. Soc., p. 66, 82-84 [with
J. R. Donnell], 86-91.
—— 1961, Abandonment of Unaweep Canyon, Mesa County, Colorado, by
capture of the Colorado and Gunnison Rivers: U.S. Geol. Survey
Prof. Paper 424-B, art. 60, p. B144-B146, fig. 60-1.
—— 1963, Geologic map of the Grand Junction area, Colorado: U.S. Geol.
Survey Misc. Inv. Ser. Map I-404.
—— 1965a, Geology and artesian water supply of the Grand Junction
area, Colorado: U.S. Geol. Survey Prof. Paper 451, 149 p.
—— 1965b, The geologic story of Colorado National Monument [with
graphics by John R. Stacy]: Fruita, Colo., Colorado and Black
Canyon Natural History Assoc., 56 p.
—— 1974, The geologic story of Canyonlands National Park, with
graphics by John R. Stacy: U.S. Geol. Survey Bull. 1327, 126
p.
—— 1975, The geologic story of Arches National Park, with graphics by
John R. Stacy: U.S. Geol. Survey Bull. 1393, 113 p.
Look, Al, 1961, John Otto and the Colorado National Monument: Denver,
Colo., Denver Westerners, Inc., 80 p., [second edition 1962 by
Sandstone Publishing Co., Grand Junction, Colo.].
Newman, W. L., 1976, Geologic time—the age of the Earth: U.S. Geol.
Survey, 20 p.
Pipiringos, G. N., and O’Sullivan, R. B., 1975, Chert pebble
unconformity at the top of the Navajo Sandstone in
southeastern Utah, _in_ Canyonlands Country, Eighth annual
field conference, Sept. 22-25, 1975, Guidebook: Durango,
Colo., Four Corners Geol. Soc., p. 149-156.
Potter, R. M., and Rossman, G. R., 1977, Desert varnish: The
importance of clay minerals: Science, v. 196, no. 4297, p.
1446-1448, June 24.
Williams, P. L., 1964, Geology, structure, and uranium deposits of the
Moab Quadrangle, Colorado and Utah: U.S. Geol. Survey Misc.
Inv. Ser., Map I-360 [reprinted 1976].
Wormington, H. M., and Lister, Robert H., 1956, Archaeological
investigation on the Uncompahgre Plateau in west-central
Colorado: Denver Mus. Nat. History Proc., no. 2, 129 p., 69
figs.
Wright, J. C., Shawe, D. R., and Lohman, S. W., 1962, Definition of
members of the Jurassic Entrada Sandstone in east-central Utah
and west-central Colorado: Bull. Am. Assoc. Petroleum
Geologists, v. 46, no. 11, p. 2057-2070.
Additional Reading
Cater, F. W., 1966, Age of the Uncompahgre uplift and Unaweep Canyon,
west-central Colorado: U.S. Geol. Survey Prof. Paper 550-C, p.
C86-C92.
Everhart, W. C., 1972, The National Park Service, Praeger Library of
U.S. Government Departments and Agencies No. 13: New York,
Praeger Publishers, p. i-xii, 1-276.
Follansbee, Robert, 1929, Upper Colorado River and its utilization:
U.S. Geol. Survey Water-Supply Paper 617, 394 p.
Gilluly, James, Waters, A. C., and Woodford, A. O., 1975, Principles
of Geology [4th ed.]: San Francisco, W. H. Freeman & Co., 527
p.
Hansen, W. R., 1965, The Black Canyon of the Gunnison, today and
yesterday: U.S. Geol. Survey Bull. 1191, 76 p.
Harris, D. V., 1978, The geologic story of the national parks and
monuments [2nd ed.]: Ft. Collins, Colo., Colo. State Univ.
Foundation Press, 325 p.
Hunt, C. B., 1956, Cenozoic geology of the Colorado Plateau: U.S.
Geol. Survey Prof. Paper 279, 99 p.
Keefer, W. R., 1971, The geologic story of Yellowstone National Park,
illustrated by John R. Stacy: U.S. Geol. Survey Bull. 1347, 92
p.
Look, Al, 1951, In my back yard: The Univ. of Denver Press, 318 p.
—— 1955, 1,000 million years on the Colorado Plateau, land of uranium:
Denver, Colo., Bell Publications, 344 p.
Miller, P. H., and Coale, B. V., 1969, Colorado National Monument, a
fantastic landscape sculptured by erosion: Fruita, Colo., The
Colorado-Black Canyon of the Gunnison Nature Assoc., Inc., 73
p.
Peale, A. C., 1877, Geological report on the Grand River district
[Colorado], _in_ F. V. Hayden, U.S. Geol. Survey of the Terr.,
Ann. Rept. 9, 1875: p. 31-101.
[Illustration: Petroglyphs]
Footnotes
[1]Reports referred to in this and some of the subsequent footnotes are
listed under “References” by authors in alphabetical order, followed
by year of publication, and other pertinent data. The report just
referred to is listed as Lohman, 1965a. Other reports of interest
are similarly listed under “Additional reading.”
[2]Lohman, 1965b.
[3]Lohman, 1974.
[4]Lohman, 1975.
[5]For a very interesting account of this colorful character, see Look,
1961-62. My statements regarding Otto were taken mainly from this
account.
[6]So-called buffalo are actually bison.
[7]1961-62, p. 19-21.
[8]Just west of the T-intersection of Monument Road and the eastern
segment of South Broadway.
[9]Wormington and Lister, 1956, p. 81, 119-122.
[10]Archaeological survey of Colorado National Monument, 1963, by George
Stroh, Jr., and George H. Ewing, with laboratory assistance by
William D. Wade. Unpublished duplicated manuscript, 62 p., map,
March 1964. For copies of this and other reports or discussions of
the subject, or both, I am greatly indebted to: Adrienne Anderson,
Regional Archaeologist, Rocky Mountain Region, National Park
Service, Denver; Bruce Rippeteau, State Archaeologist, Denver; John
Crouch, District Archaeologist, Bureau of Land Management, Grand
Junction; H. Marie Wormington, Anthropologist Emeritus, Denver
Museum of Natural History; and Al Look, Grand Junction. Copies of
this and other unpublished reports referred to are on file at the
headquarters of the Monument.
[11]Many of the cliff faces of the Wingate Sandstone, and in parts of
the Plateau other sandstones also, are darkened or blackened by
desert varnish, a natural pigment of iron and manganese oxides,
silica, and clay. (See fig. 32.) The varnish is darker on cliff
faces that have been standing longer. The prehistoric inhabitants of
the canyon country learned that effective and enduring designs could
be created simply by chiseling through the thin dark layer to reveal
the buff, tan, or pink sandstone beneath. These petroglyphs were
chiseled when the rock face was vertical; afterwards the slab fell
to a horizontal position.
[12]The Fremont people were mainly hunters who roamed the Plateau around
A.D. 850 or 900. (See Jennings, 1970.)
[13]Taken mainly from Colorado State Planning Commission, 1959,
Hamilton, 1956, Beckwith, 1854, and Hayden, 1877.
[14]Taken largely from Dellenbaugh, 1902.
[15]Information regarding Kodel and his mine was obtained mainly from Al
Look and C. Frank Moore of Grand Junction and Mrs. Irving C. Beard
of Fruita.
[16]For details see Lohman, 1965a.
[17]See Lohman, 1974.
[18]The Geological Survey has divided the Precambrian into, from oldest
to youngest, the Archean and Proterozoic Eons, with the boundary at
2,500 million years. The two eons now constitute Precambrian time.
[19]Potter and Rossman, 1977.
[20]According to Robert A. Cadigan, U.S. Geological Survey.
[21]See Pipiringos and O’Sullivan, 1975.
[22]See Wright, Shawe, and Lohman, 1962.
[23]Pipiringos and O’Sullivan, 1975.
[24]According to Fred Peterson, U.S. Geological Survey.
[25]Wright, Shawe, and Lohman, 1962; Lohman, 1975.
[26]Paul L. Williams, U.S. Geological Survey, told me in November 1978
that he observed H₂S-bearing spring water leaching the color from
both the Entrada and Wingate Sandstones above Tabeguache Creek some
8 or 10 miles north of Nucla, Colo., and from the Wingate alone
along Onion Creek in eastern Utah.
[27]Lohman, 1965a, p. 47, 48.
[28]Study of a fauna of small vertebrates from the late Jurassic
Morrison Formation of western Colorado, by George C. Callison, 21
pages, June 1978.
[29]_A_, modified from Gilmore, courtesy U.S. National Museum; _B_,
modified from Gilmore, courtesy Carnegie Museum; _C_, modified from
Mathew, courtesy American Museum of Natural History; and _D_,
modified from Romer, after Marsh and Gilmore, courtesy University of
Chicago Press.
[30]From information obtained in several discussions with John R.
Donnell. U.S. Geological Survey.
[31]See Cater, 1970, p. 67.
[32]Lohman 1961, 1965a, 1965b; Hunt 1969, p. 87.
[33]Lohman, 1960, p. 66-100, 88-91.
[34]In the following sections the small numbered triangles in the right
margin refer to key points along the trip routes. Figure 3 shows the
locations of these key points. These numbers should be especially
helpful if the reader happens to follow the road guides in reverse.
[35]One cfs, or one ft³s⁻¹, = 448.8 gallons a minute or 2446.6 cubic
meters a day.
[36]Lohman, 1965a, p. 44.
[37]Lohman, 1965a, p. 22.
[38]Lohman, 1963, 1965a.
[39]Lohman, 1965a, p. 22, 23.
[40]Lohman, 1965a, p. 106, well 33.
[41]Lohman, 1963; 1965a, pl. 1.
[42]Lohman, 1965a, p. 15.
[43]Lohman, 1965a.
[44]Lohman, 1965b.
_Index_
Italic page numbers indicate major references or pre-eminent views
Page
A
Acknowledgments, 130
Agate, 53
Airport, Walker Field, 85
Albuquerque, N. Mex., 16
Algae, 27, 47
_Allosaurus_, 4, 50, _52_, 60
Anasazi people, 129
Animals, buffalo, _3_, 91, 94, 105
cattle, 101
deer, 2
elk, 2, 109
sheep, 99
Anthropoid primates, 76
Anticlines, 61, _62_
_Apatosaurus_, 50, _52_
_excelcus_, 96
Archaeological survey, 1963, 8
Archean Eon, 24, 125
Arches, _61_
Arches National Park, XI, 36, 129
Area, Colorado National Monument, 5
Artesian wells, 14
Artifacts, Indian, 5, 8
Artificial fill, view, _98_
Artists Point, 45, 105
view, _46_
B
Balanced Rock, 99
Basalt, 71
Basins, 61, _62_, 63
Battlement Mesa, lava flows, 21, 63, 64, _71_
views, 30, 33
Beard, Irving, 12
Bentonite, 49
Black Canyon of the Gunnison National Monument, 38, 128
Black Ridge, 53, 55
Black Ridge Trail, _99_
Book Cliffs, _18_, 56, 73
coal, 60
views, 30, 33, _57_, 100
Book Cliffs View, 102, 104
_Brachiosaurus_, 50
_altithorax_, 91
monument, Riggs Hill, 90
Broadway, 86, 89, _92_-95
Brown-Stanton river expedition, 11
Brushy Basin Member, Morrison Formation, 47, 90, 96
bentonite, 49
views, _48_, _95_
Bryce Canyon National Park, 63, 130
Buffalo, 3, 91, 94, 105
Burro Canyon Formation, 53, 55, 90, 96, 118
unconformity, 118
views, 48, _54_
water, 15
C
Cactus Park, 78
Calcite, 21, 35
Callison, George, 50
_Camarasaurus_, 50
Campground, Saddlehorn, 5, 32, 86, _101_
view, 101
_Camptosaurus_, view, 52
Canyon country, 1
Canyon cutting, 78
Canyon de Chelly National Monument, 129
Canyon Lands, 16
Canyon Rim Trail, _102_, 104
views, 103, 104
Canyonlands National Park, XI, 128
Capitol Reef National Park, 36, 38, 129
Carmel Formation, 39
Cattle, 101
Caves, Wingate Sandstone, 13, 32
Cedar Breaks National Monument, 130
Cedar City, Utah, 16
Cedar Mesa Sandstone Member, 128, 129
Cedaredge, coal, 60
Cenozoic Era, 61
_Ceratosaurus_, 53
Chert, 38
Chinle Formation, 26, _28_, 79, 96, 129
faulting, 97
views, 92, 93
road cut, 99, 116
views, 19, 82, 89, _100_
Clams, 53, 55
Clark’s Wash, cave, 13
Cliff faces, erosion, 79
Coal, 49, 55, 56, 57, _60_, 89
dinosaur tracks, 60
Coke Ovens, 29, _30_, 40, 53, _105_
view, _31_
Coke Ovens Overlook, 42, _105_
Cold Shivers Point, 29, _111_
view, _112_
Colorado Highway 141, 83
Colorado Highway 340, 86, 88, 89, 94, 97, 122
Colorado mineral belt, 13
Colorado Plateau, 32, 63, 128
Colorado Plateau Province, 16
Colorado River, 11, 55, 78, 120
ancestral, 71, 72, 73, _74_, 77
future course, 83
name change, 16
Columbus Canyon, 111, _112_, 119
Como Bluff, Laramie, Wyo., 53
Cottonwood trees, view, 114
Crawford, George A., 10
Cretaceous Period, 53, 55, 60, 63
Curbstones, ripple-marked, 96
Curtis Formation, 39
Cutler Formation, 128, 129
D
Dakota Sandstone, 15, 18, 53, _55_, 89
unconformity, 118
view, _54_
De Chelly Sandstone Member, 129
DeBeque, 57, 63, 64
DeBeque Canyon, 57
Deer, mule, 2
Denver and Rio Grande Western Railroad, 85
Desert, 29
Desert varnish, _8_, 32
view, _69_
Devils Canyon, 13
Devils Kitchen, 116, 117
Devils Kitchen Picnic Area, 86, 111, 116
Dewey Bridge Member, 38, 39
Dikes, 24
Dinosaur tracks, coal, 60
Dinosaur National Monument, 36, 128
_Diplodocus_, 50
Dirty Devil River, 12
Distant View, 101
Divide Road, view, 82
Dolores River, 73, 120
ancestral, 72
Domes, drawing, 62
Dominguez, Father, 10
Dominguez Creek, 83
Donnell, John R., oil shale, 64
DS Road, 111, 120
E
Earthfill, 97, 98
East Creek, capture, _75_, 78
Burro Canyon Formation, 55
East Entrance, 85, 116
Elk, 2, 109
Elks Lodge, 2
Entrada Sandstone, _39_, 43, _45_, 101, 119
Dewey Bridge Member, 38, 39
Moab Member, 39, _40_, 42, 96, 111
views, _41_, _42_
ripplemarks, 96
road cuts, 105, 108
Slick Rock Member, 38, 39, _40_, 42, 45
views, 31, 37, _41_, 42, _43_, 44
unconformity, view, _37_
views, 31, 34, _41_, 42, 43, 44, 48, 82, 92, 106, 114
water, 15, _44_, 91, 116, 118, 120
Eocene Epoch, 61, 63, 71
Erickson, Lance, 50
Erosion, 26, 79
Escalante, Father, 10
Expedition, Powell, 11
Explorers, 10
F
Fallen Rock, view, _81_
Fallen Rock Overlook, 81, _109_
Faults, 18, _64_, 65
Glade Park, 69, 120, 121
views, 122, 123
Kodels Canyon, 65, 69, _97_
views, 67, _68_, 69
Redlands, 64, 65, 89, _92_, 94
views, _66_, 90, _93_, 107, 124
Field Columbian Museum, 50
Field Museum of Natural History, 50
Fieldwork, XI
Flagstaff, Ariz., 16
Flash floods, 97, 98, 108, 118
Folds, 64
drawings, 62
Grand Hogback monocline, 64
Ladder Creek monocline, 111
view, _66_
Lizard Canyon monocline, 65, 69, 93, 95, 97
views, _67_, 70, 94
San Rafael Swell, 36, 45, 128, 129
Uncompahgre arch, 72, 73, 77, 78
drawing, 75
Formations, rock. _See_ Rock formations.
Fossils, algae, 27, 47
_Allosaurus_, 4, 50, 52, 60
_Apatosaurus_, 50, 52
_excelcus_, 96
_Brachiosaurus_, 50, 90
_altithorax_, 91
Burro Canyon Formation, 54
Callison, George, 50
_Camarasaurus_, 50
_Camptosaurus_, 52
Carmel Formation, 39
_Ceratosaurus_, 53
Chinle Formation, 28
clams, 53, 55
Como Bluff, 53
Curtis Formation, 39
dinosaurs, 32, 60
_Diplodocus_, 50
Erickson, Lance, 50
Kayenta Formation, 35
_Morosaurus_, 50
Morrison Formation, 47, 53
oysters, 55
Redlands, The, 50, 53
reptiles, sea-going, 56
Riggs Hill, 50
Salt Wash Member, 50
sharks, 56
snails, 53
_Stegosaurus_, 50, 52
Tertiary mammals, 76
tracks, 60
_Tyrannosaurus_, 60
Wingate Sandstone, 32
wood, 28
worms, 27
Fremont culture, 9
Fremont Junction, Utah, 129
Fruita, _11_, 85
Interstate 70, 86
Fruita Canyon, 5, 49, 95, _97_
Chinle Formation, 28
dikes, 24
Kodels Canyon fault, view, _68_
views, 67, _100_
Fruita Canyon View, _101_
Fruita Paleontological area, 51, 96
Fruita Paleontological Workshop, 51
Future, 83
G
Gap in the Rock Record. _See_ Unconformities.
Garfield, James A., 1
Gateway, 27, 72
Geologic history, 125
Geologic time spiral, _126_
Glaciers, 77, 80
Glade Park, ranchers, 1, 107
Entrada Sandstone, 43, 45
Slick Rock Member, 45
Glade Park fault, 69, _120_, _121_
view, _122_, _123_
Glade Park General Store and Post Office, 13, 108
Glen Canyon Dam, 77
Glen Canyon Group, 129
Glen Canyon National Recreation Area, 128, 129
Glenwood Canyon, 76
Glenwood Springs, 27
Gneiss, 24
Goblin Valley State Park, 129
Grabens, The, 128
Grand Canyon National Park, 128
Grand County, Utah, 17
Grand Hogback monocline, 64
Grand Junction, founded, 10
Otto’s monument, 4
Grand Junction Chamber of Commerce, 1
Grand Mesa, 17, 21, 33, 63, 64, _71_, 73
lakes, 77
views, 33, 67, _107_, 113, 122
water, 15
Grand River, 10, 11, _16_
Grand Valley, 17, 56, 63, 76, 78, 85
views, 30, 57, _100_, 101
Grand View, _105_
view, 19
Granite, 24
Great Sand Dunes National Monument, 29
Green River, Utah, 11, 12, 16, 129
Green River Formation, 63, 64
view, _103_
Gunnison, John W., 10
Gunnison River, 10, 17, 78, 83, 88, 122
ancestral, 72, 73
drawing, 75
Gunsight, view, 33
Gypsum, 45
H
Hanksville, Utah, 129
Hayden Survey, 10
Hematite, 21
Henry Mountains, 38
Highland View, _107_
Highways. _See_ Roads.
Historic Trails View, _99_
History, 1
Holocene Epoch, 76, 84
Holt, Edwin L., 50
Hoover Dam, 77
I
Ice age, 77
Independence Monument, XII, 1, _29_, 105
base, 28
views, _19_, 94, 104, _107_
Independence View, 29, _105_
Inland basins, 63
Island in the Sky, 128
J
Jacobs Ladder Road, 121
Joints, 26
Juniper, 101, 109
views, 30, 68
Jurassic Period, 35, 39
K
Kaolinite, 55
Kayenta Formation, 29, _32_, 35, 97, 120, 128, 129
road cuts, 105
unconformity, view, 37
views, 19, _34_, _36_, 41, 68, 100, _103_, _106_, 117
Kissing Couple, 30, 38
Kodels Canyon, _12_, 69
Kodels Canyon fault, 65, 69, 97
views, 67, 68, 69
L
Ladder Canyon, 121, 122
Ladder Creek monocline, 111
views, _66_, _124_
Lake Mead, 77
Lake Powell, 36, 77
Lake Uinta, 63
Landslides, 77, 104
Mesaverde Group, view, _57_
Lava flows, 18, 21, _71_
Leaching, 42, 44
Liberty Cap, _108_
view, 90
Liberty Cap Trail, 90, _108_
Little Park Road, 42, 120, _121_
bentonite, 49
faulting, view, _66_
Lizard Canyon, 95, 97
view, 67
Lizard Canyon monocline, 65, 69, 95, 97, _102_
views, _67_, 93, 94
Look, Al, fossils, 50
prehistoric people, 5
quoted, 3
Lower Ute Canyon View, 109
M
Mack, Colo., _15_, 17
Mancos Shale, 18, _56_, 72
view, _57_
Maps, _87_
geologic, 22
photo index, 58
road guide, 5, _6_
Marble Canyon, 12
Meeker, Colo., 64
Meeker Massacre, 10
Mesas, 1
Mesaverde Group, 56, 57, 129
landslide, view, _57_
Mesaverde National Park, 129
Mesozoic Era, 27
Metamorphic rocks, 18
_See also_ Proterozoic rocks.
Mica mine, 122
Miller, Laura Hazel, cave dweller, 13
Minerals, agate, 53
bentonite, 49
calcite, 21, 35
chert, 38
clays, 8, 49, 55, 69
coal, 55, 56, 57, 89
desert varnish, _8_, 32, 69
gypsum, 45
hematite, 21
kaolinite, 55
mica, 122
silica, 35
uranium ore, 28, 49
vanadium ore, 49
Mining, building stones, 105
Cameo, 57
coal, 57
Devils Canyon, 13
Kodels Canyon, 12
Ladder Canyon, 122
mica, 122
oil shale, 63, 64
Palisade, 57
Miocene Epoch, 61, 71, 72
Moab, Utah, 28, 120
Moab Member, Entrada Sandstone, 39, _40_, 42, 96, 111
views, _41_, _42_
Moenkopi Formation, 129
Monoclines. _See_ Folds.
Monument, _Apatosaurus excelcus_, 96
_Brachiosaurus_, 90
Otto’s, 3
Monument Canyon, 1, 2, 3, 29, _94_, 105
views, _94_, 102, _104_
Monument Canyon Trail, 94, _105_
Monument Canyon View, _105_
Monument Headquarters, 102
Monument Road, 53, 88, _118_
Monument Valley, 128
Mormon Tea, 111
view, 33
_Morosaurus_, 50
Morrison Formation, _47_, 90, 94, 96, 128
badlands, 49, 118
bentonite, 49
Brushy Basin Member, 47, 49, 90, 96
views, 48, 95
Glade Park, 119
gypsum, 45
landslide, 104
road cuts, 107
Salt Wash Member, 15, _47_, 49, 90, 94, 107
views, _41_, _48_, 92, 95
views, 48, 92, _95_
water, 15, 118
Mount Garfield, Book Cliffs, views, 33, _57_
Mule deer, 2
Museum, Historical Museum and Institute of Western Colorado, 4
Visitor Center, 5, 102
N
Natural Bridges National Monument, 129
Navajo Sandstone, 36, 38, 129
Needles, The, 128
No Thoroughfare Canyon, 1, 5, 49, 53, 118, 121
dikes, 24
flood, 118
Glade Park fault, 69
petroglyphs, 9
tunnel, view, 115
views, 9, 48, 54, 66, 117, _122_, 123
North East Creek, 78
O
Odd Fellows, 3
Oil shale, 63
Oligocene Epoch, 61
Orchard Mesa, water, 14
Otto, John, 1, 2
monument, view, XII, 4
Otto’s Trail, 97, 104, 114
view, 107
Oysters, 55
P
Pabor, William E., 11
Paleocene Epoch, 61, 63
Paleozoic Era, 26
Palisade, 17, 57, 73
water, 15
Peach orchards, 88
Pegmatite, 24
Pennsylvanian Period, 26
Permian Period, 26
Petrified Forest National Park, 129
Petroglyphs, 8
view, 9
Photographs, XII
Photography directions, 86
Piceance Creek Basin, 64
Picnic areas, Devils Kitchen, 5, 86, 111, _116_
Headquarters area, 86
view, _102_
Piñon Mesa, 61, 84, 101, 107, 120
elk, 2, 109
Piñon pine, 101, 109
view, 30, 68
Plants, coalified wood, 49
cottonwood trees, view, 114
juniper, 101, 109
views, 30, 68
Mormon Tea, 111
view, 33
piñon pine, 101, 109
views, 30, 68
Pipe Organ, 30, _104_
view, _104_
Pipe Organ Overlook, 104
Piracy, _73_
drawing, 74
Plateau Creek, 15, 63
Pleistocene Epoch, 73, 76, 77, 78
Pliocene Epoch, 61, 72, 73
Powell, John W., expedition, 11
Powerplant, 88
Precambrian rocks. _See_ Proterozoic rocks.
Preface, XI
Prehistoric people, 5
Proterozoic Eon, 24, 26, 125
Proterozoic rocks, _24_, 72, 89, 96, 99
faulting, views, 89, _92_
views, 19, _66_, 83, 100, _112_
Q
Quaternary Period, 61, 78
R
Railroads, 10, 11, 85
Rainbow Bridge National Monument, 36, 129
Red Canyon, 3, _80_, 111
view, _33_
Red Canyon Overlook, 96, _111_
Redlands, The, 89, 97, 118, 119, 122
canals, 88
Chinle Formation, 28
fossils, 50, 53
Morrison Formation, 49
peach orchards, 88
view, 30
water, 14, 88, 94
Redlands canals, 88, 94
Redlands fault, _64_, 65, 89, _92_
views, _66_, 89, _90_, 92, 93, 94, 107, 124
Redlands Road, _3_
Redlands View, _97_
References, 131
Rifle, Colo., 16, 17, 63, 64
Riggs Hill, 50, 90
Rim Rock Drive, _4_, 32, 86, _97_-116, 119
Artists Point, 105
campground, 101
Chinle Formation, 28
earthfill, view, _98_
Entrada Sandstone, 40, 42, _105_, 108
faulting, view, 67
Fruita Canyon, view, 100
gap in rock record, 38
Kayenta Formation, 32, 105, 109
Kodels Canyon fault, view, _68_
Liberty Cap Trail, 108
Moab Member, 42
Morrison Formation, 49
Slick Rock Member, 40, _42_
Summerville Formation, 105, 108
Ute Canyon, 108
views, 34, 36, 43, 67, 68, 98, 100
Visitor Center, 102
Wingate Sandstone, 104, 111
Ripplemarks, 47, 96
Rivers, 11, 16, _72_
Road cuts, Artists Point, 45
Brushy Basin Member, 96
Burro Canyon Formation, 53
Chinle Formation, 28, 99, 116
Entrada Sandstone, 42, 105, 108
Fruita Canyon, 28
Kayenta Formation, 36, 101, 105, 109
Moab Member, 42
Morrison Formation, 49, 96, 107
No Thoroughfare Canyon, 28
Proterozoic rocks, 99, 116
Salt Wash Member, 107
South Broadway, monument, view, _91_
Summerville Formation, 45, 105, 107, 108
Ute Canyon, 36, 45
Wingate Sandstone, 97, 99, 111, 116
Road guides. _See_ Trip guides.
Road stops, Artists Point, 105
Coke Ovens Overlook, 105
Devils Kitchen, 116
Distant View, 101
Fallen Rock Overlook, 109
view, 81
Fruita Canyon View, 101
Grand View, 105
Highland View, 107
Historic Trails View, 99
Independence View, 105
Lower Ute Canyon View, 109
Monument Canyon View, 105
Pipe Organ Overlook, 104
Red Canyon Overlook, 96, 111
Redlands fault, _92_
Redlands View, 97
Upper Ute Canyon View, 109
Roads, Broadway, 86, 89, _92_-95
Colorado Highway 141, view, 82
Colorado Highway 340, 86, 88, 89, 94, 97, 122
Divide Road, view, 82
DS Road, 111, _120_
Fruita, 4
Jacobs Ladder Road, 121
Little Park Road, 42, 49, 66, 120, _121_, _122_
Monument Road, 53, 88, _118_
Rim Rock Drive, _4_, 28, 32, 34, 38, 40, 42, 43, 47, 49, 67, 68,
86, _97_-116, 119
South Broadway, 86, _89_-92, 118
South Camp Road, 86, _89_, 90, 108, 118
U.S. Highway 6, 85, 88
U.S. Highway 24, 85
U.S. Highway 50, 85, 88, 122
U.S. Interstate 70, 63, 85, 96
Utah Highway 128, 120
Wingate Drive, 92
Roan Cliffs, _64_, 71
views, 19, 100, _103_
Rock column, 20
Rock formations, Balanced Rock, 99
Coke Ovens, 29, 30, 40, 105
view, 31
Cold Shivers Point, 29, 111
view, _112_
Devils Kitchen, 116
view, 117
Fallen Rock, view, _81_
Grabens, The, 128
Gunsight, The, 33
Independence Monument, 1, 29, _105_
views, _19_, 94, _107_
Kissing Couple, 30, 38
Liberty Cap, 108
view, 90
Needles, The, 128
petroglyphs, 116
Pipe Organ, 30
view, 104
Saddlehorn, 40, _101_
views, 101, 102, _106_
Sentinal Spire, 30
Squaw Fingers, 30
White Rock, view, 92
Window Rock, _102_
view, _103_
Rock leaching, 42, 44
Rocks, breakup, 26
types, _18_
Rosevale, 122
Roubidoux, Joseph, settler, 10
Rough Canyon, 121
Ruby Canyon, 83
S
Saddlehorn, 40, _101_
campground, 86, 101
picnic area, 86, 101
views, 101, 102, _106_
Sagebrush, 120
Sahara, 29
Salt Wash Member, Morrison Formation, _47_, 90, 94, 107
uranium, 49
views, 41, _48_, 92, 95
water, 15
San Miguel River, ancestral, 72
San Rafael Swell, 36, 45, 128, 129
Sand dunes, 29, 36
Schist, 24
Seagoing reptiles, 56
Sentinal Spire, 30
Serpents Trail, 1, 2, _111_
views, 30, 49, 66, 113, _114_
Sharks, 56
Sheep, 99
Silica, 35
Size, Colorado National Monument, 5
Slick Rim, 42
Slick Rock, Colo., 40
Slick Rock Member, 38, 39, _40_, 42, 45
views, 31, 37, _41_, 42, _43_, 44
Snail shell, 53
South Broadway, 86, _89_-92, 118
South Camp Road, 86, _89_, 90, 108, 118
Squaw Fingers, 30
_Stegosaurus_, 50
view, 52
Stream cutting, 79
Summerville Formation, 39, _45_, 47
road cuts, 105, 108
views, 41, 42, _46_
Sunset Crater National Monument, 130
Synclines, 61
T
Taft, William Howard, 1
Tertiary Period, 61, 71, 76
Thunderstorms, damage, 97, 108, 118
Tools, prehistoric people, 8
Trails, 1
Black Ridge, _99_
builder, 1
Canyon Rim, _102_, 104
views, 103, 104
Coke Ovens, 105
Grand View, 105
Liberty Cap, 90, 108
Lizard Canyon, 97
Lower Ute Canyon View, 109
Monument Canyon, 94, _105_
No Thoroughfare Canyon, 1
Otto’s, 97, 104, 114
Serpents, 1, 2, _111_
views, 30, 49, 66, 113, _114_
Ute Canyon, 108, 109
Window Rock Nature Trail, _102_, 104
Triassic Period, 27, 28, 29, 35
Trip guides, East Entrance to Grand Junction, 118
Fruita to West Entrance, 96
Glade Park, 119
Grand Junction to West Entrance, 88
Little Park Road, 121
West to East Entrances, 97
_Tyrannosaurus_, 60
U
Uinta Lake, 63
Unaweep Canyon, 72, _73_, 78, _80_
ancestral, 76
piracy, drawing, 75
view, _82_
Uncompahgre arch, 61, 72, 73, 77, 78
drawing, 75
Uncompahgre Complex, 8
Uncompahgre Highland, 26
Uncompahgre Plateau, 26, 28, 49, 77, 107
Unconformities, 26, 35, 54, 104
views, _37_, 41, 54
U.S. Highway 6, 85, 88
U.S. Highway 24, 85
U.S. Highway 50, 85, 88, 122
U.S. Interstate 70, 63, 85, 96
Utah Highway 128, 120
Ute Canyon, 2, 3, 40, 45, 80, 119
Fallen Rock, view, _81_
Liberty Cap, 108
Summerville Formation, 45
view, _110_
Ute Canyon Trail, 108, 109
Ute Canyon View, Lower, 109
Ute Canyon View, Upper, 109
Ute Indians, 5, 10
V
Visitor Center, 5, 32, 40, 86, _102_
view, _106_
Volcanics, 18, 71
W
Walker Field, 85
Wasatch Formation, 63, 64, 129
Water, _14_, 15, 79, 91
Entrada Sandstone, 15, 91, 116, 118
leaching action, 42, 44
Morrison Formation, 15, 118
Redlands, The, 14, 88, 94
Wingate Sandstone, 15, 91, 95
West Creek, ancestral, 76
West Entrance, 85, 89, 95
White Rock, view, 92
Whitewater, 83
Window Rock, _102_
view, _103_
Window Rock Nature Trail, _102_, 104
Wingate Drive, 92
view, 93
Wingate Sandstone, _29_, 79, 89, 96, 128, 129
cave, 14
desert varnish, 32
faulting, 97
views, _66_, _68_, _69_, 89, _90_, 92, 93, _107_
folds, view, 66, _102_
petroglyphs, view, 9
Rim Rock Drive, 99, 104, 116
road cuts, 99, 116
sand dunes, view, 30
views, 14, 19, _30_, 31, 34, 66, 69, 82, _100_, 106, 114, _115_,
117, 122
water, 15, 91, 95
Worms, 27
Wupatki National Monument, 129
Z
Zion National Park, 36, 38, 129
★ U.S. GOVERNMENT PRINTING OFFICE: 1981—778-836
[Illustration: U. S. Department of the Interior, March 3, 1849]
Transcriber’s Notes
—Retained publication information from the printed edition: this eBook
is public-domain in the country of publication.
—Corrected a few palpable typos.
—Included a transcription of the text within some images.
—Renumbered footnotes, and modified references to them accordingly.
—In the text versions only, text in italics is delimited by
_underscores_.
—The HTML version contains relative hyperlinks to these companion
volumes, so that offline copies can be interlinked:
—Canyonlands National Park, Gutenberg eBook #51048,
—Arches National Park, Gutenberg eBook #51116.
*** End of this LibraryBlog Digital Book "The Geologic Story of Colorado National Monument - Revised Edition" ***
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