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+Project Gutenberg (https://www.gutenberg.org) public repository for
+eBook #51116 (https://www.gutenberg.org/ebooks/51116)
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-The Project Gutenberg EBook of The Geologic Story of Arches National Park, by 
-S. W. Lohman
-
-This eBook is for the use of anyone anywhere in the United States and most
-other parts of the world at no cost and with almost no restrictions
-whatsoever.  You may copy it, give it away or re-use it under the terms of
-the Project Gutenberg License included with this eBook or online at
-www.gutenberg.org.  If you are not located in the United States, you'll have
-to check the laws of the country where you are located before using this ebook.
-
-Title: The Geologic Story of Arches National Park
-       Geological Survey Bulletin 1393
-
-Author: S. W. Lohman
-
-Illustrator: John R. Stacy
-
-Release Date: February 3, 2016 [EBook #51116]
-
-Language: English
-
-Character set encoding: UTF-8
-
-*** START OF THIS PROJECT GUTENBERG EBOOK GEOLOGIC STORY--ARCHES NATIONAL PARK ***
-
-
-
-
-Produced by Stephen Hutcheson, Dave Morgan and the Online
-Distributed Proofreading Team at http://www.pgdp.net
-
-
-
-
-
-
-    [Illustration: Geology of Arches National Park]
-
-    [Illustration: BALANCED ROCK, guarding The Windows section of Arches
-    National Park. Rock is Slick Rock Member of Entrada Sandstone
-    resting upon crinkly bedded Dewey Bridge Member of the Entrada.
-    White rock in foreground is Navajo Sandstone. La Sal Mountains on
-    right skyline. (Frontispiece)]
-
-    [Illustration: Graphic Title Page]
-
-
-
-
-                        _The Geologic Story of_
-                                 Arches
-                             NATIONAL PARK
-
-
-                            By S. W. Lohman
-                              Graphics by
-                             John R. Stacy
-
-                    GEOLOGICAL SURVEY BULLETIN 1393
-
-
-                UNITED STATES DEPARTMENT OF THE INTERIOR
-                    ROGERS C. B. MORTON, _Secretary_
-
-                           GEOLOGICAL SURVEY
-                       V. E. McKelvey, _Director_
-
-    [Illustration: Department of the Interior · March 3, 1949]
-
-                 U.S. GOVERNMENT PRINTING OFFICE: 1975
-
-
-  Library of Congress Cataloging in Publication Data
-  Lohman, Stanley William, 1907-
-  The geologic story of Arches National Park.
-  (Geological Survey Bulletin 1393)
-  Bibliography: p.
-  Includes index.
-  Supt. of Docs. no.: I 19.3:1393
-  1. Geology—Utah—Arches National Park—Guide-books.
-  2. Arches National Park, Utah—Guide-books.
-  I. Title. II. Series: United States Geological Survey
-  Bulletin 1393.
-  QE75.B9 No. 1393 [QE170.A7] 557.3′08s [557.92′58]
-  74-23324
-
-
- For sale by the Superintendent of Documents, U. S. Government Printing
-                                 Office
-                        Washington, D. C. 20402
-                      Stock Number 024-001-02598-1
-
-
-
-
-                                Contents
-
-
-                                                                     Page
-  Beginning of a monument                                               1
-  Graduation to a park                                                  5
-  Early history                                                         9
-      Prehistoric people                                                9
-      Late arrivals                                                    12
-  Geographic setting                                                   18
-  Deposition of the rock materials                                     20
-  Bending and breaking of the rocks                                    24
-  Uplift and erosion of the Plateau                                    33
-  Origin and development of the arches                                 37
-      Examples of arches                                               46
-  How to see the park                                                  50
-  A trip through the park                                              52
-      Colorado River canyon                                            52
-      Headquarters area                                                57
-      Courthouse Towers area                                           63
-      The Windows section                                              68
-      Delicate Arch area                                               74
-      Fiery Furnace                                                    79
-      Salt Valley and Klondike Bluffs                                  82
-      Devils Garden                                                    83
-  Summary of geologic history                                          98
-  Additional reading                                                  104
-  Acknowledgments                                                     105
-  Selected references                                                 105
-  Index                                                               109
-
-
-
-
-                                Figures
-
-
-                                                                     Page
-  Frontispiece. Balanced Rock.
-  1. Arches National Park                                               6
-  2. Rock art in Arches National Park                                  11
-  3. Wolfe’s Bar-DX Ranch                                              14
-  4. Rock column of Arches National Park                               21
-  5. Common types of rock folds                                        25
-  6. Common types of rock faults                                       26
-  7. Paradox basin                                                     27
-  8. Geologic section across northwest end of Arches National Park     28
-  9. Index map of northwestern part of Arches National Park            28
-  10. Gravity anomalies over Salt Valley                               31
-  11. Tilted block of rocks in Cache Valley graben                     34
-  12. Jointed northeast flank of Salt Valley anticline                 36
-  13. Index map                                                        38
-  14. Tunnel Arch                                                      43
-  15. “Baby Arch”                                                      44
-  16. Broken Arch                                                      45
-  17. Double Arch                                                      47
-  18. Pothole Arch                                                     48
-  19. Glen Canyon Group                                                53
-  20. Navajo Sandstone cliffs                                          54
-  21. Mouth of Salt Wash                                               55
-  22. Southeast end of faulted Cache Valley anticline                  56
-  23. Faulted Seven Mile-Moab Valley anticline                         58
-  24. Three Penguins                                                   59
-  25. Moab Valley                                                      60
-  26. Faulted wall of Entrada Sandstone                                61
-  27. Park Avenue                                                      62
-  28. Balanced rocks on south wall of Park Avenue                      64
-  29. Courthouse Towers                                                65
-  30. The Three Gossips                                                66
-  31. Sheep Rock                                                       66
-  32. Petrified sand dunes                                             67
-  33. “Hoodoos and goblins”                                            68
-  34. Eye of The Whale                                                 69
-  35. Intricate crossbeds in Navajo Sandstone                          70
-  36. Cove Arch and Cove of Caves                                      71
-  37. North Window                                                     72
-  38. Looking southwestward through North Window                       73
-  39. South Window                                                     74
-  40. Turret Arch                                                      75
-  41. Parade of Elephants                                              76
-  42. Suspension foot bridge across Salt Wash                          78
-  43. Delicate Arch                                                    78
-  44. Fiery Furnace                                                    80
-  45. Trail to Sand Dune Arch                                          81
-  46. Sand Dune Arch                                                   82
-  47. Tower Arch                                                       84
-  48. Skyline Arch                                                     85
-  49. Campground in Devils Garden                                      86
-  50. View north from campground                                       87
-  51. Southeastern part of Devils Garden trail                         88
-  52. Pine Tree Arch                                                   89
-  53. Landscape Arch                                                   91
-  54. Navajo Arch                                                      92
-  55. Partition Arch                                                   93
-  56. Double O Arch                                                    93
-  57. Dark Angel                                                       94
-  58. “Indian-Head Arch”                                               95
-  59. Geologic time spiral                                             96
-
-    [Illustration: Petroglyph figure]
-
-
-
-
-Beginning of a Monument
-
-
-According to former Superintendent Bates Wilson (1956), Prof. Lawrence
-M. Gould, of the University of Michigan, was the first to recognize the
-geologic and scenic values of the Arches area in eastern Utah and to
-urge its creation as a national monument. Mrs. Faun McConkie Tanner[1]
-told me that Professor Gould, who had done a thesis problem in the
-nearby La Sal Mountains, was first taken through the area by Marv
-Turnbow, third owner of Wolfe cabin. (See p. 12.) When Professor Gould
-went into ecstasy over the beautiful scenery, Turnbow replied, “I didn’t
-know there was anything unusual about it.”
-
-Dr. J. W. Williams, generally regarded as father of the monument, and L.
-L. (Bish) Taylor, of the Moab Times-Independent, were the local leaders
-in following up on Gould’s suggestion and, with the help of the Moab
-Lions Club, their efforts finally succeeded on April 12, 1929, when
-President Herbert Hoover proclaimed Arches National Monument, then
-comprising only 7 square miles.[2] It was enlarged to about 53 square
-miles by President Franklin D. Roosevelt’s Proclamation of November 25,
-1938, and remained at nearly that size, with some boundary adjustments
-on July 22, 1960, until it was enlarged to about 130 square miles by
-President Lyndon B. Johnson’s Proclamation of January 20, 1969.
-
-According to Breed (1947), Harry Goulding, of Monument Valley, in a
-specially equipped car, traversed the rugged sand and rocks of the
-Arches region in the fall of 1936 and, thus, became the first person to
-drive a car into The Windows section of Arches National Monument. Soon
-after, a bulldozer followed Harry’s tracks and made a passable trail.
-
-When my family and I visited the monument in 1946, the entrance was
-about 12 miles northwest of Moab on U.S. Highway 163 (then U.S. 160),
-where Goulding’s old tire tracks led eastward past a small sign reading
-“Arches National Monument 8 miles.” This primitive road crossed the
-sandy, normally dry Courthouse Wash and ended in what is now called The
-Windows section. At that time there was no water or ranger station, nor
-were there any picnic tables or other improvements within the monument
-proper, and the custodian was housed in an old barracks of the Civilian
-Conservation Corps near what is now the entrance, 5 miles northwest of
-Moab.
-
-Former Custodian Russell L. Mahan reported (oral commun., May 1973) that
-soon after our initial visit in 1946 a 500-gallon tank was installed
-near Double Arch in The Windows section and connected to a drinking
-fountain and that two picnic tables and a pit toilet were added. At that
-time the only access to Salt Valley and what is now called Devils Garden
-was a primitive dirt road which, according to Breed (1947, p. 175), left
-old U.S. Highway 160 (now U.S. 163) 24 miles northwest of Moab, went 22
-miles east, then followed Salt Valley Wash down to Wolfe cabin (fig. 1).
-
-According to Abbey (1971), who served as a seasonal ranger beginning
-about 1958, a sign had by then been erected at the crossing of
-Courthouse Wash which read:
-
-                           WARNING: QUICKSAND
-                           DO NOT CROSS WASH
-                         WHEN WATER IS RUNNING
-
-The ranger station, his home for 6 months of the year, was what Abbey
-described as “a little tin housetrailer.” Nearby was an information
-display under a “lean-to shelter.” He had propane fuel for heat,
-cooking, and refrigeration, and a small gasoline-engine-driven generator
-for lights at night. His water came from the 500-gallon tank, which was
-filled at intervals from a tank truck. At that time there were three
-small dry campgrounds, each with tables, fireplaces, garbage cans, and
-pit toilets. By that time an extension of the dirt road led northward to
-Devils Garden, and some trails had been built and marked.
-
-Bates Wilson became Custodian of the monument in 1949 and later became
-Superintendent not only of Arches but also of the nearby new Canyonlands
-National Park (Lohman, 1974) and the more distant Natural Bridges
-National Monument. In the fall of 1969, Bates told me of some of his
-early experiences in the undeveloped monument, including the evening
-when 22 cars were marooned on the wrong (northeast) side of Courthouse
-Wash after a flash flood. Bates and his “lone” ranger brought ropes,
-coffee, and what food they could obtain in town after closing time,
-threw a line across the swollen stream, had a tourist pull a rope
-across, then took turns wading the stream with one hand on the rope and
-the other balancing supplies on his shoulder. After a fire had been
-built and hot coffee and food passed around, the spirits of the stranded
-group rose considerably, except for one irate woman from the East, who
-refused to budge from her car. Bates and his helper finally got the last
-car out about 1 a.m., after the flood had subsided, and Mrs. Wilson then
-supplied lodging and more food and coffee for those who needed it.
-
-During and for sometime after World War II and the Korean War, lack of
-maintenance funds and personnel had prevented improvement of the
-facilities in many of our national parks and monuments, particularly in
-undeveloped ones like Arches. The day was saved through the wisdom and
-foresight of former Park Service Director Conrad L. Wirth, who saw the
-need and desirability of putting the whole “want” list into one
-attractive, marketable package. In the words of Everhart (1972, p. 36):
-
-  Selection of a name is of course recognized as the most important
-  decision in any large-scale enterprise, and here Wirth struck pure
-  gold. In 1966 the Park Service would be celebrating its fiftieth
-  anniversary. What a God-given target to shoot for! Why not produce a
-  ten-year program, which would begin in 1956, aimed to bring every park
-  up to standard by 1966—and call it Mission 66?
-
-The ensuing well-documented and cost-estimated plan for Mission 66 was
-enthusiastically backed by President Dwight D. Eisenhower and approved
-and well supported by Congress to the tune of more than $1 billion
-during the 10-year period. For Arches, this included a new entrance,
-Park Headquarters, Visitor Center, a museum boasting a bust of founder
-Dr. Williams, and modern housing for park personnel, all 5 miles
-northwest of Moab. By 1958 (Pierson, 1960) a fine new paved road between
-Park Headquarters and Balanced Rock (frontispiece) was completed. These
-badly needed improvements were followed by the completion of the paved
-road all the way to Devils Garden, the building of the modern
-campground, picnic facilities, and amphitheater in the Devils Garden,
-and the construction of turnouts and marked trails.
-
-    [Illustration: Petroglyph figure]
-
-
-
-
-Graduation to a Park
-
-
-Arches graduated to a full-fledged national park when President Richard
-M. Nixon signed a Congressional Bill on November 16, 1971. The change in
-status was accompanied by boundary changes that reduced the area to
-about 114 square miles. The loss of most of Dry Mesa, just east of the
-present boundary (fig. 1), was offset in part by gains of new land
-northwest of Devils Garden. The present (1974) boundaries, roads,
-trails, and named features of the park are shown in figure 1.
-
-The park was virtually completed at graduation time, and so far this
-change in status has shown up mainly in new entrance signs, a new 1972
-brochure and map, and a very informative “Guide to an Auto Tour of
-Arches National Park,” keyed to numbered signs at parking spaces. About
-all that remain to be added are new wayside exhibits, some boundary
-fences, and spur roads and trails.
-
-    [Illustration: ARCHES NATIONAL PARK, showing location in Utah,
-    boundaries, streams, highways and roads, trails, landforms,
-    principal named features, and the city of Moab. The reader is
-    referred to figure 7 and to road maps issued by the State or by oil
-    companies for the locations of other nearby towns and features.
-    Visitors also may obtain pamphlets, from the entrance station or
-    from the National Park Service office in Moab, which contain
-    up-to-date maps of the park and the latest available information on
-    roads, trails, campsites, and picnic sites. (Fig. 1)]
-
-Although Arches had officially become a park in November 1971, it was
-not formally dedicated until May 15, 1972. The ceremony began by having
-the Federal, State, and local dignitaries and other guests totaling 140
-persons board the _Canyon King_, a 93-foot replica of a Mississippi
-River sternwheeler (Lansford, 1972; Lohman, 1974, fig. 69), for its
-maiden voyage down the Colorado River. After about half an hour, the
-heavily laden boat became stuck on a sandbar, and after a 90-minute wait
-the passengers were rescued by jet boats. This delayed a luncheon at the
-Visitor Center put on by the Moab Lions Club. Following the luncheon,
-Park Superintendent Bates Wilson made a brief welcoming address, then
-introduced J. Leonard Volz, Director of the Midwest Region of the
-National Park Service, who served as master of ceremonies. Speakers
-included Utah Governor Calvin L. Rampton, Senator Frank E. Moss, a
-representative of Senator Wallace F. Bennett, Representatives Sherman P.
-Lloyd of Utah and Wayne Aspinall of Colorado, and Mitchell Melich,
-Solicitor General of the Department of Interior, representing Secretary
-Rogers C. B. Morton. After the speeches, a commemorative plaque, donated
-by the Canyonlands Natural History Association, was unveiled by Senator
-Moss and Mr. Melich.
-
-Most of the color photographs were taken by me on 4- × 5-inch film in a
-tripod-mounted press camera, using lenses of several focal lengths, but
-a few were taken on 35-mm film, using lenses of various focal lengths. I
-am grateful to several friends for the color photographs credited to
-them in the figure captions. The black and white photographs were kindly
-loaned from the Moab and Arches files of the National Park Service. The
-points from which most of the photographs were taken are shown in figure
-13.
-
-    [Illustration: Petroglyph figure]
-
-
-
-
-Early History
-
-
-                           Prehistoric People
-
-The Canyon lands in and south of Arches were inhabited by cliff dwellers
-centuries before the first visits of the Spaniards and fur trappers.
-Projectile points and other artifacts found in the nearby La Sal and
-Abajo Mountains indicate occupation by aborigines during the period from
-about 3000-2000 B.C. to about A.D. 1 (Hunt, Alice, 1956). The Fremont
-people occupied the area around A.D. 850 or 900, and the Pueblo or
-Anasazi people from about A.D. 1075 to their departure in the late 12th
-century (Jennings, 1970). Most of the evidence for these early
-occupations has been found in and south of Canyonlands National Park
-(Lohman, 1974), but some traces of these and possibly earlier cultures
-have been found also within Arches National Park.
-
-Ross A. Maxwell (National Park Service, written commun., 1941)
-investigated two caves in the Entrada Sandstone in the upper reaches of
-Salt Wash that contain Anasazi ruins. He mentioned that perhaps a dozen
-or more other caves should be checked for evidence of former occupation
-and, also, that he found several ancient campsites littered with flint
-chips and broken tools.
-
-One cave Maxwell explored some 5 miles north of Wolfe Ranch and north of
-the park is about 300 feet long and 100 to 150 feet deep. It contains
-the remains of one or more ruins of a structure he thought may have
-covered much of the floor. The remaining parts of walls now are only two
-to four tiers of stones in height, although originally they may have
-been more than one story high. Maxwell explored a second cave on the
-east side of Salt Wash, about 2 miles north of Wolfe Ranch, which
-contains 16 storage cists of adobe.
-
-The faces of many older sandstone cliffs or ledges are darkened by
-desert varnish—a natural pigment of iron and manganese oxides. The
-prehistoric inhabitants of the Plateau learned that effective and
-enduring designs, called petroglyphs, could be created simply by
-chiseling or pecking through the thin dark layer to reveal the buff or
-tan sandstone beneath. Most petroglyphs were created by the Anasazi, but
-those showing men mounted on horses were done by Ute tribesmen after the
-Spaniards brought in horses in the 1500’s. The Fremont people and some
-earlier people painted figures on rock faces, called pictographs, and
-some of these had pecked outlines.
-
-The so-called “Moab panel” was described by Beckwith (1934, p. 177) as a
-petroglyph, but, as pointed out by Schaafsma (1971, p. 72, 73), it
-comprises figures having pecked outlines and painted bodies, which
-actually are combinations of petroglyphs and pictographs. This
-beautifully preserved group of paintings is shown in the upper
-photograph of figure 2. Mrs. Schaafsma goes on to say, concerning the
-“Moab panel”:
-
-  The long tapered body, the antenna like headdresses, and the staring
-  eyes are characteristic features of Barrier Canyon style figures
-  elsewhere * * *. Of special interest here are the large shields held
-  by certain figures. A visit to this site indicated that the shields,
-  although apparently of some antiquity, have been superimposed over
-  some of the Barrier Canyon figures. Whether or not this was done by
-  the Barrier Canyon style artists themselves or later comers to the
-  site is impossible to tell.
-
-Although definite proof seems lacking, she suggested (written commun.,
-Nov. 3, 1973) that the “‘Barrier Canyon style’[3] * * * is earlier than
-the work in the same region clearly attributable to the Fremont.” Note
-the three bullet holes in and near the right-hand shield. A ledge above
-the panel that contained petroglyphs during her earlier visit had fallen
-to the base of the cliff by the time my wife and I inspected the panel
-in September 1973.
-
-    [Illustration: ROCK ART IN ARCHES NATIONAL PARK. A (above), “Moab
-    panel,” on cliff of Wingate Sandstone above U.S. Highway 163 between
-    Courthouse Wash and Colorado River, believed to be the work of
-    “Barrier Canyon” style people. B (below), Petroglyphs on ledge of
-    sandstone in Morrison Formation on east side of Salt Wash just north
-    of Wolfe Ranch, believed to have been cut by Ute tribesmen. (Fig.
-    2)]
-
-    [Illustration: Fig. 2 B]
-
-Mrs. Schaafsma believes the petroglyphs in the lower photograph of
-figure 2 to be the work of Ute tribesmen, not only because of the
-horses, but also because of the stiff-legged appearance of the mountain
-sheep. Note the bullet hole above the panel.
-
-
-                             Late Arrivals
-
-Later arrivals in and near Arches National Park included first Spanish
-explorers, then trappers, cattlemen, cattle rustlers and horse thieves,
-followed in the present century by oil drillers, uranium hunters,
-jeepsters, and tourists. Butch Cassidy, the Sundance Kid, and other
-members of The Wild Bunch are known to have frequented parts of what is
-now Canyonlands National Park (Baker, Pearl, 1971), but it is not
-certain whether or not any of them traversed what is now Arches National
-Park.
-
-The first settler in what is now Arches National Park was a Civil War
-veteran named John Wesley Wolfe, who was discharged from the Union Army
-about 3 weeks before the Battle of Bull Run because he suffered from
-varicose veins. In 1888 his doctor told him he had to leave Ohio for a
-dryer climate or he would not live 6 months, so he took his son Fred
-west and settled on a tract of 150 acres along the west bank of Salt
-Wash, where his “Wolfe cabin” still stands (figs. 1, 3). From family
-letters and newspaper clippings compiled by Mrs. Maxine Newell and other
-members of the National Park Service (Maxine Newell, written commun.,
-1971), we learn what life in the area was like:
-
-  We have started a cattle spread on a desert homestead. We call it the
-  Bar-DX Ranch. Fred and I live in a little log house on the bank of a
-  creek that is sometimes dry, sometimes flooded from bank to bank with
-  roaring muddy water. We are surrounded with rocks—gigantic red rock
-  formations, massive arches and weird figures, the like of which youve
-  [sic] never seen. The desert is a hostile, demanding country, hot in
-  summer, cold in winter. The Bar-DX Ranch is a day’s ride from the
-  nearest store, out of the range of schools.
-
-Although John Wolfe had promised his wife and his other children that he
-would return home the first fall that his cattle sales netted enough
-money, he and Fred stayed on and on, and his wife refused to go west and
-join her husband and son. Eighteen years later he sent money from his
-pension check to his daughter, Mrs. Flora Stanley, his son-in-law, Ed
-Stanley, and his two grandchildren, Esther and Ferol, to join him and
-Fred at the ranch. Their train was met at Thompson Springs (now
-Thompson), Utah (fig. 7), by John Wolfe for the 30-mile ride to the
-ranch by horse and wagon. Sight of the tiny log cabin with only a dirt
-floor brought tears to his daughter’s eyes, but her spirits rose
-considerably after John Wolfe promised to build a new log cabin with a
-wooden floor. But the children were enchanted with this strange country,
-with the building of the new cabin, and, especially, with getting to go
-rabbit hunting with Grandpa Wolfe. The Stanleys stayed at the ranch
-until Esther was 10, then moved to Moab to await the arrival of their
-third child, Volna.
-
-In 1910 John Wolfe sold the Bar-DX Ranch, and the entire family moved to
-Kansas. John Wolfe later moved back to Ohio, and died at Etna, Licking
-County, on October 22, 1913, at the age of 84, 25 years after his doctor
-had warned him to move to a dryer climate or face an early death.
-
-Wolfe had sold his spread to Tommy Larson, who later sold it to J. Marv
-Turnbow and his partners, Lester Walker and Stib Beeson. The old log
-cabin gradually came to be known as the “Turnbow cabin,” and this name
-appeared on early maps of the area by the U.S. Geological Survey and on
-early pamphlets by the National Park Service, partly because Marv
-Turnbow served as a camphand in 1927 assisting in the first detailed
-geologic mapping of the area (Dane, 1935, p. 4). In 1947 the ranch was
-sold to Emmett Elizondo, who later sold it to the Government for
-inclusion in what was then the monument.
-
-From information supplied by Wolfe’s granddaughter, Mrs. Esther Stanley
-Rison, and his great-granddaughter, Mrs. Hazel Wolfe Hastler, who
-visited the cabin in July 1970, the original name Wolfe cabin, or Wolfe
-Ranch, has been restored, and appears on the newer maps and pamphlets.
-(See fig. 1.) What remains of Wolfe’s Bar-DX Ranch is shown in figure 3.
-
-    [Illustration: WOLFE’S BAR-DX RANCH, on west bank of Salt Wash at
-    start of trail to Delicate Arch. Left to right: Corral, wagon, “new”
-    cabin, and root cellar. “Old” cabin, which formerly was to right of
-    photograph, was washed away by a flood in 1906. (Fig. 3)]
-
-Arches National Park is surrounded by active uranium and vanadium mines
-and by many test wells for oil, gas, and potash; it is underlain by
-extensive salt and potash deposits. Oil and gas are produced a few miles
-to the north and east, and potash is being produced about 12 miles to
-the south (Lohman, 1974).
-
-Uranium and vanadium have been mined on the Colorado Plateau since 1898
-(Dane, 1935, p. 176) and in the Yellow Cat area (also called Thompson’s
-area), just north of the park (fig. 1), since about 1911 (Stokes, 1952,
-p. 7). The deposits in the Yellow Cat area occur in the Salt Wash
-Sandstone Member of the Morrison Formation (fig. 4). According to Pete
-Beroni (U.S. Atomic Energy Commission, oral commun., August 6, 1973),
-some ore is still being produced in the Yellow Cat area, and the
-production of vanadium ore will increase as soon as the uranium mill at
-Moab is converted to also handle vanadium ore. The Corral and so-called
-Shinarump mines along the southwest side of Moab Canyon just north of
-Sevenmile Canyon (fig. 1) are still actively producing uranium ore from
-the Moss Back Member of the Chinle Formation, according to Mr. Beroni.
-
-The occurrences of salt and potash in and near the park and the attempts
-to find oil and gas nearby are discussed in a recent report (Hite and
-Lohman, 1973), and the deposits beneath Moab, Salt, and Cache Valleys
-are discussed in later chapters.
-
-In 1955 and 1956 the Pacific Northwest Pipeline, known also as the
-“Scenic Inch,” was constructed by the Pacific Northwest Pipeline Corp.
-to transmit natural gas from wells in the San Juan Basin of northwestern
-New Mexico for a total of 1,487 miles to the Pacific Northwest, with
-additional pickups from gas fields in northeastern Utah, northwestern
-Colorado, and southwestern Wyoming (Walters, 1956). This 26-inch
-pipeline follows the general route of U.S. Highway 163 from Cortez,
-Colo., past Moab to Sevenmile Canyon 10 miles northwest of Moab, where
-it turns abruptly to the northeast and crosses about the middle of
-Arches National Park. It crosses the park road and the flat area between
-the Fiery Furnace and the southeast end of Devils Garden, but the scars
-are so well healed that most visitors are unaware of its existence
-unless they happen to look southwestward across Salt Valley, where the
-filled excavation is still visible. The filled trench also appears in
-the lower middle of figure 23.
-
-Unlike Canyonlands National Park a few miles to the south, Arches was
-not on the route of the famous early-day river expeditions of John
-Wesley Powell or of most of those that followed; however, the
-southeastern boundary of the park is the Colorado River, formerly the
-Grand, which was traversed by the first leg of the ill-fated
-Brown-Stanton expedition (Dellenbaugh, 1902, p. 343-369; Lohman, 1974).
-
-The canyon of the Colorado River along the southeastern park boundary is
-deep and beautiful and is a favorite stretch of quiet water for boaters
-and floaters. Partly paved State Highway 128 on the east bank is a part
-of a most scenic drive from Moab to Cisco—a small railroad town about 32
-miles northeast of the eastern border of figure 1 (fig. 7). This road
-has been variously called the “Moab Mail Road,” the “Cisco Cutoff,” the
-“Dewey Road,” or the “Dewey Bridge Road” after an old suspension bridge
-(fig. 7) across the Colorado River at the old townsite of Dewey about 12
-miles south of Cisco. During the summer this deep colorful canyon may be
-viewed at night by artificial illumination. Each evening one-half hour
-after sundown, an 80-passenger jet boat leaves a dock north of the
-highway bridge, carries passengers several miles upstream, then floats
-slowly downstream followed by a truck on the highway carrying 40,000
-watts of searchlights which play back and forth on the colorful red
-canyon walls, while the passengers listen to a taped discourse. The
-entire trip requires about 2 hours.
-
-The spectacular arches and red rocks of Arches and vicinity have been
-used to advantage in making color movies and color TV shows. Parts of
-the recent Walt Disney film “Run, Cougar, Run” were filmed beneath
-Delicate Arch (fig. 43), in Professor Valley of the Colorado River just
-east of the park (fig. 7), and in other sections of the canyon country.
-
-Ever since military jet aircraft broke the sound barrier, there has been
-a growing number of protests from concerned citizens, organizations, and
-National Park Service officials concerning the dangers sonic booms have
-posed to Indian ruins and delicate erosional forms in our national parks
-and monuments, such as natural bridges, arches and windows, balanced
-rocks, and natural spires or towers. Many instances of damaged ruins,
-roads, erosional forms, and broken windows were reported. My wife and I
-can vouch for the destructive power of such booms, for in October 1969,
-while we were having breakfast at Squaw Flat Campground in The Needles
-section of Canyonlands National Park, a particularly severe blast from a
-low-flying jet not only violently rocked our jack-supported trailer but
-broke the windshield of our car.
-
-At Arches National Park, particular fear was felt for Landscape Arch
-(fig. 53), thought to be the longest natural stone arch in the world,
-and many a special round trip from headquarters involving 47 road miles
-and 2 trail miles was made to check on the condition of this arch after
-especially loud sonic booms were heard. Finally, in April 1972,
-following a rash of newspaper and magazine articles that spread across
-the nation, the Secretary of the Air Force put a virtual stop to this
-danger by ruling that, except in an emergency (Moab Times-Independent,
-April 12, 1972):
-
-  Supersonic flights must not only avoid passing over national parks,
-  they also may not fly near them, according to the new regulation. For
-  each 1,000 feet of altitude, the pilot must allow one-half mile
-  between the flight path and the park boundary. The regulation also
-  prohibits supersonic flights below 30,000 feet (over land) so the high
-  speed planes must allow 15 miles between the nearest park boundary and
-  the flight path.
-
-Let us hope that with the aid of this long-needed regulation and
-cooperation from visitors, the arches will remain intact for many more
-generations to see.
-
-    [Illustration: Petroglyph figure]
-
-
-
-
-Geographic Setting
-
-
-Geologists have divided the United States into many provinces, each of
-which has distinctive geologic and topographic characteristics that set
-it apart from the others. One of the most intriguing and scenic of these
-is the Colorado Plateaus province, referred to in this report simply as
-the Colorado Plateau, or the Plateau (Hunt, C. B., 1956, fig. 1). This
-province, which covers some 150,000 square miles and is not all
-plateaus, as we shall see, 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. Arches National Park occupies part of the Canyon Lands
-Section, one of the six subdivisions of the Plateau. As the names imply,
-the Canyon Lands Section of the Plateau comprises a high plateau
-generally ranging in altitude from 5,000 to 7,000 feet, which has been
-intricately dissected by literally thousands of canyons.
-
-Arches National Park is drained entirely by the Colorado River, whose
-deep canyon borders the park on the southeast (fig. 1). Most of the park
-is drained by Salt Wash, which enters the Colorado River just southeast
-of The Windows section, but the southwestern part is drained by
-Courthouse Wash and Moab Canyon, whose flows join the Colorado just west
-of the bridge on which U.S. Highway 163 crosses the river.
-
-When viewed at a distance of 1 foot, the shaded relief map (fig. 1)
-shows the general shape of the land surface in and near Arches National
-Park to the same horizontal scale as it would appear to a person in a
-spacecraft flying at a height of 250,000 feet, or about 47.5 miles. This
-map was prepared from part of the reverse side of a plastic-relief
-map[4] at a scale of 1:250,000 by the U.S. Army Map Service of the Moab
-quadrangle, using a simple time- and money-saving method (Stacy, 1962).
-
-    [Illustration: Petroglyph figure]
-
-
-
-
-Deposition of The Rock Materials
-
-
-The vivid and varied colors of the bare rocks and the fantastic buttes,
-spires, columns, alcoves, caves, arches, and other erosional forms of
-Arches National Park result from a fortuitous combination of geologic
-and climatic circumstances and events unequalled in most other parts of
-the world.
-
-First among these events was the piling up, layer upon layer, of
-thousands of feet of sedimentary rocks under a wide variety of
-environments. Sedimentary rocks of the region are composed of clay,
-silt, sand, and gravel carried and deposited by moving water; silt and
-sand transported by wind; and some materials precipitated from water
-solutions, such as limestone (calcium carbonate), dolomite (calcium and
-magnesium carbonate), gypsum (calcium sulfate with some water),
-anhydrite (calcium sulfate alone), common salt (sodium chloride), potash
-minerals, such as potassium chloride, and a few other less common types.
-Some of the beds were laid down in shallow seas that once covered the
-area or in lagoons and estuaries near the sea. Other beds were deposited
-by streams in inland basins or plains, a few were deposited in lakes,
-and the constituents of deposits like the Navajo Sandstone, were carried
-in by the wind. The character and thickness of the exposed sedimentary
-rocks and the names and ages assigned to them by geologists are shown in
-the rock column (fig. 4) and in the cross section (fig. 8). The history
-of their deposition is summarized on pages 98-102. Figure 4 was compiled
-mainly from generalized sections given by A. A. Baker (1933), Dane
-(1935), McKnight (1940), and Wright, Shawe, and Lohman (1962), and, in
-part, from Hite and Lohman (1973).
-
-    [Illustration: ROCK COLUMN OF ARCHES NATIONAL PARK. Average
-    thickness of units 250-1,000 feet is exaggerated two times; those
-    less than 250 feet, four times. 1 foot = 0.305 meter. (Fig. 4)]
-
-
-  AGE (millions of yrs ago)
-    GEOLOGIC AGE
-      NAME OF ROCK UNIT
-            KIND OF ROCK AND HOW IT IS SCULPTURED BY EROSION
-              THICKNESS (feet)
-                NAMED FOR OCCURRENCE AT OR NEAR
-
-
-  100
-    Late Cretaceous
-      Mancos Shale
-            Lead-gray fossiliferous marine shale. Forms slopes.
-              ?
-                Mancos, Colo.
-      Dakota Sandstone
-            Conglomeratic sandstone, gray shale, carbonaceous shale, and
-                  coal. Forms ledge.
-              100
-                Dakota, Nebr.
-      Unconformity
-    Late Jurassic
-      Morrison Fm.
-              700
-                Morrison, Colo.
-        Brushy Basin Member
-            Variegated shale, some sandstone and conglomerate, petrified
-                  wood, chert, and dinosaur bones. May contain some beds
-                  of Burro Canyon (Early Cretaceous) age.
-        Salt Wash Member
-            Crossbedded white and gray conglomeratic sandstone beds and
-                  lenses, locally carnotite bearing, and red and gray
-                  sandy mudstone. Forms slopes.
-      Unconformity
-  160
-      San Rafael Group
-                (San Rafael Swell, Utah)
-        Summerville Fm.
-            Thin bedded red sandstone and shale. Some cherty limestone
-                  concretions. Forms slopes.
-              0-40
-                Summerville Point, Utah
-        Entrada Ss.
-                (Entrada Point, Utah)
-          Moab Member
-            White, crossbedded fine-grained sandstone. Caps Slick Rock
-                  Member north of Devils Garden and Fiery Furnace and on
-                  Klondike Bluffs.
-              0-100
-                Moab, Utah
-          Slick Rock Member
-            Salmon-colored to pink and white fine-grained generally
-                  crossbedded sandstone, containing some medium- to
-                  coarse-grained sand. Generally forms cliffs or narrow
-                  fins many of which contain arches or windows.
-              0-240
-                Slick Rock, Colo.
-          Dewey Bridge Member
-            Red muddy sandstone and sandy mudstone, with contorted
-                  bedding. Forms easily eroded bases to arches in
-                  Windows Section, hence aided in their development.
-              0-175
-                Dewey Bridge, Utah
-      Unconformity
-  190
-    Jurassic and Triassic(?);
-      Glen Canyon Group
-        Navajo Sandstone
-            Massive crossbedded buff, gray, and white fine-grained
-                  sandstone, and local beds of gray limestone. Forms
-                  cliffs along Colorado River, floors Windows Section.
-              0-350
-                Navajo Country, Four Corners (Glen Canyon, U.)
-    Late Triassic(?)
-        Kayenta Formation
-            Lavender, gray, and white lenses of sandstone, red sandy
-                  shale, and conglomerate. Contains some freshwater
-                  shells. Caps and protects cliffs of Wingate Sandstone.
-              0-250
-                Kayenta, Ariz.
-    Late Triassic
-        Wingate Sandstone
-            Massive, horizontally bedded and crossbedded reddish buff
-                  fine-grained sandstone. Forms vertical cliffs along
-                  Colorado River, Cache Valley, Salt Wash, and
-                  Courthouse Wash.
-              0-350
-                Fort Wingate, N. Mex.
-  200
-      Chinle Formation
-            Irregularly bedded buff to red sandstone, red mudstone,
-                  limestone, and conglomerate. Lenticular sandstone and
-                  conglomerate (Moss Back Member) locally at base.
-                  Freshwater shells, petrified wood, reptile bones.
-                  Forms slopes.
-              0-700
-                Chinle Valley, Ariz.
-                Moss Back Ridge, Utah  Unconformity
-    Middle(?) and Early Triassic
-      Moenkopi Formation
-            Thin-bedded brown shale, gray and brown sandstone, arkosic
-                  grit, and conglomerate. Crops out on southwest side of
-                  Moab Valley and in several places in Salt and Cache
-                  Valleys. Forms slopes.
-              0-1,300
-                Moenkopi Wash, Ariz.
-      Unconformity
-  250
-    Permian
-      Cutler Formation
-            Chocolate brown and red sandy shale, maroon and pinkish-gray
-                  arkose and conglomerate. Lower part probably
-                  equivalent in age to Rico Formation in areas to south
-                  and east. Crops out in Moab Canyon west of Moab fault.
-                  Forms slopes.
-              0-2,500
-                Cutler Creek, Colo.
-    Pennsylvanian
-      Hermosa Formation
-        Unnamed upper member
-            Gray marine fossiliferous sandy limestone, gray and
-                  greenish-gray sandstone and sandy shale, and red sandy
-                  shale. Exposed in ledges southwest of Moab fault in
-                  highway cut west of park entrance.
-              0-1,500
-                Hermosa Creek, Animas River Valley, Colo.
-  300
-        Paradox Member
-            Salt, gypsum, and anhydrite, with black and gray shale and
-                  limestone. Few exposures in Salt and Cache Valleys.
-                  Forms slopes.
-              0-11,000
-                Paradox Valley, Colo.
-      Unconformity
-    Pennsylvanian(?)
-      Unnamed conglomerate
-            Yellow sandstone with boulders of limestone and chert
-                  containing Mississippian fossils. Exposed at two
-                  places in Salt Valley.
-              ?
-
-
-Not exposed in the area but present far beneath the sedimentary cover
-and exposed in several places a few miles to the northeast are examples
-of the other two principal types of rocks—(1) igneous rocks, solidified
-from molten rock forced into or above preexisting rocks along cracks,
-joints, and faults, and (2) much older metamorphic rocks, formed from
-other preexisting rock types by great heat and pressure at extreme
-depths. Igneous rocks of Tertiary age (fig. 59) form the nearby La Sal
-Mountains. The particles comprising the sedimentary rocks in the area
-were derived by weathering and erosion of all three types of rocks in
-various source areas.
-
-Arches National Park and nearby Canyonlands National Park are both in
-the heart of the Canyon Lands Section of the Plateau; therefore, it is
-only reasonable to wonder why the differences in their general character
-seemingly outweigh their similarities. First, let us consider the
-similarities. Both parks are underlain by dominantly red sedimentary
-rocks, both parks feature unusual erosional forms of sandstone, and both
-contain beautiful natural arches, although the arches in Canyonlands are
-restricted almost entirely to the southeastern part of The Needles
-section and are in much older rocks than those in Arches.
-
-To be sure, differences in the rocks themselves play a part in the
-dissimilarity of the two parks, and these differences are of two types.
-First, there are lateral changes in the character of the strata, known
-to geologists as facies changes, brought about by differences in the
-environment, in the type of materials, and in the mode of deposition
-even within relatively short distances. Thus, during parts of the
-Permian Period while sand, later to be known as the Cedar Mesa and White
-Rim Sandstone Members of the Cutler Formation, was being deposited in
-the southern part of Canyonlands, red mud, silt, and sand of the Cutler
-were laid down farther north in Canyonlands (Lohman, 1974, fig. 9), and
-similar, though somewhat coarser, beds of the Cutler were laid down at
-Arches (fig. 4). Further comparisons of the rock columns in the two
-parks show that while limestones of the Rico Formation were being
-deposited in a shallow sea in the southern part of Canyonlands,
-additional red mud, silt, and sand of the Cutler were being laid down
-above sea level in areas to the northeast. The source of the coarser
-materials was the ancient Uncompahgre Highland, which stood above sea
-level from Late Pennsylvanian time to Late Triassic time (figs. 7, 59).
-Although wider and longer, it occupied about the same position as the
-present Uncompahgre Plateau between Grand Junction and Gateway, Colo.
-Streams eroded the hard igneous and metamorphic rocks from this ancient
-landmass and dumped the material into basins to the northeast and
-southwest. The basin to the southwest, now called the Paradox basin
-(after Paradox Valley, Colo.), at intervals contained shallow seas and
-lagoons, which I will discuss later.
-
-Comparison of the rock columns for the two parks also reveals other
-differences. Both parks contain exposures of rocks as old as the
-Pennsylvanian Paradox Member of the Hermosa Formation. However, only in
-the Horseshoe Canyon Detached Unit of Canyonlands are rocks as young as
-the Jurassic Entrada Sandstone, whereas all the spectacular natural
-arches that make Arches famous were formed in the Entrada Sandstone, and
-Arches also contains several younger formations of Jurassic and
-Cretaceous age (fig. 4).
-
-A commonly asked question is “Why are most of the rocks so red,
-particularly those in which the arches were formed?” This can be
-answered with one word—iron, the same pigment used in rouge and in paint
-for barns and boxcars. 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, generally
-only 1 to 3 percent, is enough to produce even the darkest shades of
-red. The white or nearly white Navajo Sandstone and the Moab Member of
-the Entrada Sandstone contain little or no iron.
-
-As pointed out by Stokes (1970, p. 3), microscopic examination of the
-colored grains of quartz or other minerals shows the pigment to be
-merely a thin coating on and between white or colorless particles. Sand
-or silt weathered from such rocks soon loses its color by the scouring
-action of wind or water, so that most of the sand dunes and sand bars
-are white or nearly so.
-
-
-
-
-                   Bending And Breaking of The Rocks
-
-
-Perhaps the greatest geologic contrast between these two closely
-adjacent parks lies in their different geologic structure—the kind and
-amount of bending and breaking of the once nearly flat lying strata.
-Consolidated rocks, particularly brittle types, are subject to two types
-of fracturing by Earth forces. Joints are fractures along which no
-movement has taken place. Faults are fractures along which there has
-been displacement of the two sides relative to one another (fig. 6). As
-noted in the report on Canyonlands National Park (Lohman, 1974), the
-strata there, particularly along the valley of the Green River, are
-virtually flat lying or have only very gentle dips. Along the Colorado
-River above the confluence with the Green, however, the slightly dipping
-strata are interrupted by several gentle anticlinal and synclinal folds
-(fig. 5) and by at least one fault (fig. 6). The largest of these
-folds—the Cane Creek anticline, which crosses the Colorado River north
-of Canyonlands—has yielded oil in the past and is now yielding potash by
-solution mining of salt beds in the Paradox Member of the Hermosa
-Formation.
-
-    [Illustration: COMMON TYPES OF ROCK FOLDS. Top, Anticline, or
-    upfold; closed anticlines are called domes. Bottom, Syncline, or
-    downfold; closed synclines are called basins. From Hansen (1969, p.
-    31, 108). (Fig. 5)]
-
-In strong contrast to Canyonlands, Arches National Park contains three
-northwesterly trending major folds and is bordered on the southwest by a
-fourth. The largest and most important are the collapsed Salt Valley and
-Cache Valley anticlines, which separate the two most scenic groups of
-arches and other erosional forms—Eagle Park, Devils Garden, Fiery
-Furnace, and Delicate Arch on the northeast, and Klondike Bluffs,
-Herdina Park, and The Windows section on the southwest. Farther
-southwest is the Courthouse syncline, containing the attractive group of
-erosional forms called Courthouse Towers (fig. 1). Finally, near the
-southwest edge of the park, is the Seven Mile-Moab Valley anticline
-(also known as the Moab-Spanish Valley anticline), whose southwest limb
-is cut off by the Moab fault (figs. 7, 23). The folds just named and the
-sharply contrasting geologic structures of the two parks are well shown
-on sheet 2 of the geologic map of the Moab quadrangle (Williams, 1964),
-and the geologic formations are shown in color on sheet 1.
-
-    [Illustration: COMMON TYPES OF FAULTS. Top, Normal, or gravity
-    fault, resulting from tension in and lengthening of the Earth’s
-    crust. Bottom, reverse fault, resulting from compression in and
-    shortening of the Earth’s crust. Low-angle reverse faults generally
-    are called overthrusts or overthrust faults. In both types, note
-    amount of displacement and repetition of strata. Displacements may
-    range from a few inches or feet to many thousands of feet. From
-    Hansen (1969, p. 116). (Fig. 6)]
-
-    [Illustration: PARADOX BASIN, in southeastern Utah and southwestern
-    Colorado, showing the extent of common salt and major potash
-    deposits in the Paradox Member of the Hermosa Formation, and the
-    salt anticlines. Adapted from Hite (1972, fig. 1B). (Fig. 7)]
-
-    [Illustration: GEOLOGIC SECTION ACROSS NORTHWEST END OF ARCHES
-    NATIONAL PARK, showing strata beneath Courthouse syncline and Salt
-    Valley anticline. For line of section, see figure 9. Caprock
-    consists of gypsum and shale, from which common salt has been
-    leached by ground water, covered by alluvium. Heavy slanted lines
-    near crest of anticline are faults. Adapted from Hite and Lohman
-    (1973, fig. 13). (Fig. 8)]
-
-    [Illustration: INDEX MAP OF NORTHWESTERN PART OF ARCHES NATIONAL
-    PARK, showing axes of Courthouse syncline and Salt Valley anticline,
-    line of section _A_-_A_′ in figure 8 and line of section _B_-_B_′ in
-    figure 10. Open circles along line of section are sites of test
-    wells for oil, gas, or potash. Adapted from Hite and Lohman (1973,
-    fig. 12). (Fig. 9)]
-
-Arches National Park and most of nearby Canyonlands National Park lie
-within what geologists have termed the “Paradox basin,” which contains a
-remarkable assemblage of sediments called the Paradox Member of the
-Hermosa Formation. These deposits were laid down in shallow seas and
-lagoons during Middle Pennsylvanian time, roughly 300 million years ago
-(fig. 59). As indicated in figure 4, the Paradox Member contains, in
-addition to shale and limestone, minerals deposited by the evaporation
-and concentration of sea water—common salt, gypsum, anhydrite, and
-potash salts. For this reason such deposits are collectively called
-evaporites. Figure 7 also shows that the northeastern part of the
-Paradox basin, which is the deepest part, contains a series of partly
-alined anticlines which have cores of salt and, hence, are called salt
-anticlines. As might be expected, roughly alined synclines intervene
-between the anticlines, but are not shown because of space limitations.
-According to Cater (1970, p. 50): “The salt anticlines of Utah and
-Colorado are unique in North America both in structure and in mode of
-development.” To this may be added that they also are relatively rare in
-the world.
-
-A section across the Salt Valley anticline and the Courthouse syncline
-in the northwestern part of the park is shown in figure 8, and the axes
-of these structures are shown in figure 9.
-
-Normally, a series of roughly parallel northwestward-trending folds
-would result from shortening of a segment of the Earth’s crust by
-compressive forces from the northeast and the southwest, but such does
-not seem to be the origin of these folds. The folds occur in a
-relatively narrow belt along the northeastern part of the Paradox basin,
-the deepest part, which was broken by a series of northwesterly trending
-normal faults (fig. 6) that cut the deep-lying Precambrian and older
-Paleozoic rocks (fig. 8) prior to the deposition of the salt-bearing
-Paradox Member of the Hermosa Formation. Movement along these faults
-continued intermittently during and after deposition of the Paradox,
-however, and resulted in the formation of a series of northwesterly
-trending ridges and troughs. Following Paradox time, normal sediments
-derived from a rising landmass to the northeast began to fill the basin.
-These sediments accumulated most rapidly and to greater thicknesses in
-the fault-derived troughs. Salt differs from normal sediments in two
-properties critical to the development of salt anticlines: first, salt
-is considerably lighter (fig. 10), and, second, salt under pressure will
-flow slowly by plastic deformation, much like ice in a glacier flows
-slowly downstream. Thus, salt in the troughs underlying the thicker and
-heavier masses of sediments was squeezed into the adjoining ridges,
-causing them to rise. Once started, this process tended to be
-self-perpetuating, as the flow of salt from beneath the thick masses of
-sediments in the troughs made room for the accumulation of still greater
-thicknesses of normal sediments. Consequently, the troughs receiving
-most of the sediments began to form downfolds, or synclines, and the
-ridges receiving little or no normal sediments began to form huge salt
-rolls that later were to become the cores of the salt anticlines when
-finally the ridges too were buried by sediments. Thus, the cross section
-(fig. 8) shows about 12,000 feet of the Paradox Member beneath the crest
-of the Salt Valley anticline and only about 2,000 feet beneath the
-Courthouse syncline. Near the middle of these structures farther to the
-southeast, all the Paradox Member has been squeezed out from beneath the
-bordering synclines.
-
-    [Illustration: GRAVITY ANOMALIES OVER SALT VALLEY, along line _B-B′_
-    shown in figure 9, and relative densities and shapes of rock bodies
-    beneath. Densities are in grams per cubic centimeter. Gravity values
-    are in milligals, as shown. The standard acceleration of gravity is
-    980.665 centimeters per second per second; 1 gal is equal to 1
-    centimeter per second per second, and 1 milligal is one thousandth
-    of a gal. Modified from Case and Joesting (1972, fig. 2). (Fig. 10)]
-
-The general shape of the Salt Valley anticline is shown also by
-cross-section _B-B′_ (fig. 10), taken along the northeast-southwest line
-_B-B′_ in figure 9, which is based upon so-called gravity anomalies over
-Salt Valley. The lighter Paradox Member, having an average density of
-2.20, has a lower gravitational attraction than the heavier rocks on
-each side, which have an average density of 2.55.
-
-By this time you are doubtless wondering why prominent upfolds of the
-rocks, such as the Salt Valley anticline and associated Cache Valley
-anticline and the Seven Mile-Moab Valley anticline, now underlie
-relatively deep valleys bordered by prominent ridges. The formation of
-these valleys was not simple and involved many steps extending over a
-considerable amount of geologic time, as portrayed by Cater (1970, fig.
-13; 1972, fig. 4). For a part of the story, let us reexamine the cross
-section (fig. 8); the rest of the story will be told in the section on
-“Uplift and Erosion.”
-
-Figure 8 shows that the unnamed upper member of the Hermosa Formation
-and the overlying Cutler and Moenkopi Formations are thickest beneath
-the Courthouse syncline but wedge out against the flanks of the
-anticline. Although the Chinle Formation and younger rocks appear to
-extend across the fold, and may have extended across this part of the
-fold, in Colorado all rocks older than the Jurassic Morrison wedge out
-against the flanks of the salt anticlines (Cater, 1970, p. 35) and also
-in the widest part of the Salt Valley anticline southwest of the section
-in figure 8. The salt anticlines were uplifted in a series of pulses so
-that some formations either were not deposited over the rising
-structures or were removed by erosion before deposition of the next
-younger unit. By Morrison time the supply of salt beneath the synclines
-seems to have become used up; hence, the anticline stopped rising, and
-the Morrison and younger formations were deposited across the
-structures. Thus, in figure 4, the minimum thickness of all units older
-than the Morrison is given as zero. Figure 4 shows the marine Mancos
-Shale to be the youngest rock unit exposed in the park, but the
-Mesaverde Group of Late Cretaceous age and possibly the early Tertiary
-(fig. 59) Wasatch Formation may have been deposited and later removed by
-erosion.
-
-
-
-
-                   Uplift And Erosion of The Plateau
-
-
-Next among the main events leading to the formation of landforms in the
-park was the raising and additional buckling and breaking of the Plateau
-by Earth forces partly during the Late Cretaceous but mainly during the
-early Tertiary. After uplift and deformation, the Plateau was vigorously
-attacked by various forces of erosion, and the rock materials pried
-loose or dissolved were eventually carted away to the Gulf of California
-by the ancestral Colorado River. Some idea of the enormous volume of
-rock thus removed is apparent when one looks down some 2,000 feet to the
-river from any of the high overlooks farther south, such as Dead Horse
-Point (Lohman, 1974, fig. 15). Not so apparent, however, is the fact
-that younger Mesozoic and Tertiary rocks more than 1 mile thick once
-overlaid this high plateau but have been swept away by erosion. In all,
-the river has carried thousands of cubic miles of sediment to the sea
-and is still actively at work on this gigantic earth-moving project. In
-an earlier report (Lohman, 1965, p. 42) I estimated that the rate of
-removal may have been as great as about 3 cubic miles each century. For
-a few years the bulk of the sediment was dumped into Lake Mead, but now
-Lake Powell is getting much of it. When these and other reservoirs
-ultimately become filled with sediment—for reservoirs and lakes are but
-temporary things—the Gulf of California will again become the burial
-ground.
-
-According to Cater (1970, p. 65-67), who made an intensive study of the
-salt anticlines, collapse of their crests seemingly occurred in two
-stages—the first stage following Late Cretaceous folding; the second
-following uplift of the Plateau later in the Tertiary. Solution and
-removal of salt by ground water played the leading role in the ultimate
-collapse.
-
-    [Illustration: TILTED BLOCK OF ROCKS IN CACHE VALLEY GRABEN, viewed
-    to the east toward Cache Valley from point on gravelled side road to
-    Wolfe’s cabin, about half a mile east of paved road. Steep slope on
-    left composed of Jurassic Morrison Formation, hogback on top formed
-    by Dakota Sandstone of Late Cretaceous age, and gentle slopes to
-    right composed of the Mancos Shale of Late Cretaceous age. (Fig.
-    11)]
-
-As shown by Dane (1935, pl. 1, p. 121-126), collapse of the Salt Valley
-and Cache Valley anticlines was accompanied by considerable faulting and
-jointing, particularly along their northeast sides; by the upward
-intrusion of two large areas of the Paradox Member of the Hermosa
-Formation, one just northwest of the park and one in the middle of Salt
-Valley south of the campground; and by two downdropped masses of rock
-known to geologists as grabens (pronounced gräbǝns)—one just northwest
-of the park and one called the Cache Valley graben, which extends both
-east and west from Salt Wash. The Cache Valley graben has preserved from
-erosion the youngest rock formations in the park, as shown in figure 11.
-
-The remarkable jointing of the rocks on the northeast limb of the Salt
-Valley anticline is shown in figure 12. All the arches in this section
-of the park were eroded through thin fins of the Slick Rock Member of
-the Entrada Sandstone, and some, like Broken Arch, figure 16, are capped
-by the Moab Member.
-
-Differences in the composition, hardness, arrangement, and thickness of
-the rock layers determine their ability to withstand the forces of
-fracturing and erosion and, hence, whether they tend to form cliffs,
-ledges, fins, or slopes. Most of the cliff- or ledge-forming rocks are
-sandstones consisting of sand deposited by wind or water and later
-cemented together by silica (SiO₂), calcium carbonate (CaCO₃), or one of
-the iron oxides (such as Fe₂O₃), but some hard, resistant ledges are
-made of limestone (calcium carbonate). The rock column (fig. 4) shows in
-general how these rock formations are sculptured by erosion and how they
-protect underlying layers from more rapid erosion. The nearly vertical
-cliffs along the lower reaches of Salt and Courthouse Washes and the
-Colorado River canyon upstream from Moab consist of the well-cemented
-Wingate Sandstone protected above by the even harder sandstones of the
-Kayenta Formation. (See figs. 21, 22.) To borrow from an earlier report
-of mine (Lohman, 1965, p. 17), “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 than the Wingate, so even a few feet of the
-Kayenta * * * protect the rock beneath.” In some places, as shown in
-figures 19 and 20, the overlying Navajo Sandstone makes up the topmost
-unit of the cliff.
-
-    [Illustration: JOINTED NORTHEAST FLANK OF SALT VALLEY ANTICLINE,
-    viewed westward from an airplane. Light-colored wedge in middle
-    background is Salt Valley bordered on extreme left by Klondike
-    Bluffs. Dark-colored fins and pinnacles on left, of Slick Rock
-    Member of the Entrada Sandstone, form Devils Garden. Sharp pinnacle
-    above valley is the Dark Angel. (See fig. 57.) White bands of
-    sandstone extending to foreground are composed of Moab Member of the
-    Entrada. Note vegetation in the joints. Photograph by National Park
-    Service. (Fig. 12)]
-
-Last but far from least among the factors responsible for the grandeur
-of Arches National Park and the Plateau in general is the desert
-climate, which allows one to see virtually every foot of the vividly
-colored naked rocks, and which has made possible the creation and
-preservation of such a wide variety of fantastic sculptures. A wetter
-climate would have produced a far different, smoother landscape in which
-most of the rocks and land forms would have been hidden by vegetation.
-On the Plateau the vegetation grows mainly on the high mesas and the
-narrow flood plains bordering the rivers, but scanty vegetation also
-occurs on the gentle slopes or flats.
-
-The combination of layers of sediments of different composition,
-hardness and thickness, the bending and breaking of the rocks, and the
-desert climate, has produced steep slopes having many cliffs, ledges,
-and fins with generally sharp to angular edges, rather than the subdued
-rounded forms of more humid regions.
-
-
-
-
-                  Origin And Development of The Arches
-
-
-Among the questions commonly asked by visitors are, “How do arches
-form?”, “Why are some openings called windows, others arches?”, “What is
-the difference, if any, between arches or windows and natural bridges,
-such as those at Natural Bridges National Monument?”, and “How many
-arches are there in Arches National Park?” Before taking up the origin
-and development of arches, I shall attempt to explain the differences
-between the three types of natural rock openings named above and comment
-upon the number of arches.
-
-    [Illustration: INDEX MAP, showing localities where most of the
-    photographs were taken. Arrows point to distant views. Numbers refer
-    to figure numbers. (Fig. 13)]
-
-I believe most geologists and geographers are in general agreement with
-Cleland (1910, p. 314) that “a ‘natural bridge’ is a natural stone arch
-that spans a valley of erosion. A ‘natural arch’ is a similar structure
-which, however, does not span an erosion valley.” According to this
-definition, Natural Bridges National Monument includes three true
-bridges, whereas all the larger rock openings in Arches National Park
-with which I am familiar are properly termed “arches,” but some are
-called windows. If we were to distinguish between arches and windows, we
-might say that arches occur at or near the base of a rock wall, as do
-the doors of a house or building, whereas windows are found well above
-ground level. This distinction was not followed in naming the rock
-openings in the park, however; for example, Tunnel Arch (fig. 14) is
-considerably higher above the ground than North Window (figs. 37, 38) or
-South Window (fig. 39).
-
-As to the number of arches in the park, I might begin by saying that
-there is no universal agreement as to how large a rock opening must be
-to qualify as an arch. The pamphlet formerly handed to visitors entering
-the park proclaimed that “Nearly 90 arches have been discovered, and
-others are probably hidden away in remote and rugged parts of the area,”
-but the average visitor probably sees less than a third of this number.
-
-David May, Assistant Chief of Interpretation and Resource Management,
-Moab office of National Park Service (oral commun., Oct. 1973), believes
-that if only those in the park having a minimum dimension of 10 feet in
-any one direction were considered to be arches, the number would boil
-down to about 56 or 57. The most complete count of arches and other
-openings in all of southeastern Utah was made by Dale J. Stevens,
-Professor of Geography at Brigham Young University, during the period
-February through April 1973. He considered those with openings of 3 feet
-or larger and found more than 300 in southeastern Utah, of which 124 are
-in Arches National Park, although he stated that several areas of the
-park were not intensively searched because of time limitations (written
-commun., July and Sept. 1973). The 124 arches and openings are
-distributed among the several named areas of the park, as follows:
-Courthouse Towers, 13; Herdina Park, 11; The Windows section, 25;
-Delicate Arch area, 3; Fiery Furnace, 19; Devils Garden, 25; upper
-Devils Garden (northwest of Devils Garden), 14; Eagle Park, 2; and
-Klondike Bluffs, 12.
-
-Professor Stevens generally used a range finder or a steel tape to
-measure the width and height of the openings and the width and thickness
-of the spans, but estimated a few of the dimensions. In the text
-descriptions of arches or captions of figures that follow, I am
-including all or part of these measurements, without further
-acknowledgment.
-
-All the arches in the park were formed in the Entrada Sandstone, mainly
-in the Slick Rock Member but partly in the Slick Rock and Dewey Bridge
-Members, and a few in the Slick Rock Member occur not far beneath the
-base of the overlying Moab Member. The sandstone of the three members is
-composed mainly of quartz sand cemented together by calcium carbonate
-(CaCO₃), which also forms the mineral calcite and the rock known as
-limestone, but the Dewey Bridge Member also contains beds of sandy
-mudstone. Limestone and calcite are soluble in acid, even in weak acid
-such as carbonic acid, HHCO₃, also written H₂CO₃, formed by the solution
-of carbon dioxide (CO₂) in water. Ground water, found everywhere in rock
-openings at different depths beneath the land surface, contains
-dissolved carbon dioxide derived from decaying organic matter in soil,
-from the atmosphere, and from other sources. Even rainwater and snow
-contain a little carbon dioxide absorbed from the atmosphere—enough to
-dissolve small amounts of limestone or of calcite cement from sandstone.
-The calcite cement in the Entrada and in many other sandstones is
-unevenly distributed, however, so that all the cement is removed first
-from places that contain the least amounts, and, once the cement is
-dissolved away, the loose sand is carried away by gravity, wind, or
-water.
-
-Both nearly flat but slightly irregular beds of sandstone and relatively
-thin walls or fins of sandstone are prime targets for this differential
-erosion. Potholes, as shown in figure 18_A_, may be formed in relatively
-flat beds by the dissolving action of repeated accumulations of
-rainwater or snowmelt, even in arid regions like the Plateau.
-
-Relatively thin walls, or fins as they are called in parts of the
-Plateau including Arches, are targets for the formation of alcoves and
-caves by solution of cement and removal of sand by gravity, wind, and
-water, aided by the prying action of frost in joints, bedding planes, or
-other openings. Once a breakthrough of a wall or fin occurs, weakened
-chunks from the ceiling tend to fall, and natural arches of various
-shapes and sizes are produced. Arches form the strongest shapes for
-supporting overlying rock loads, as the rock in the arch is compressed
-toward each abutment by the heavy loads. Blocks of compressed rock
-beneath a relatively flat ceiling tend to be dislodged also by expansion
-due to release of pent-up pressure, until a strong self-supporting arch
-is formed. Release of pent-up pressure in rock walls may help also in
-initiating the formation of alcoves or caves in cliff faces. Man,
-including the ancient Greeks, Romans, Egyptians, and others, has long
-made use of arches in building bridges, aqueducts, temples, cathedrals,
-and other enduring edifices.
-
-As vividly shown in figure 12, the Entrada Sandstone on the northeast
-flank of the Salt Valley anticline has been broken by Earth forces into
-thin slabs mostly 10 to 20 feet thick between nearly parallel joints,
-but, as will be noted in the descriptions of individual arches, some
-rock walls are only 1 or 2 feet thick, whereas others are 50 feet thick
-or more. Some weak or thin slabs have weathered away, leaving the
-stronger or thicker ones as towering fins, particularly in the Fiery
-Furnace and Devils Garden areas. Jointing on a less spectacular scale
-also has broken the Entrada in areas south of Salt Valley, leaving walls
-or fins of rock.
-
-    [Illustration: TUNNEL ARCH, reached by short trail north of main
-    trail through Devils Garden. Opening is 26½ feet wide and 22 feet
-    high; span is about 14 feet thick. (Fig. 14)]
-
-Although all the arches in the park were carved from the Entrada
-Sandstone, slight differences in their mode of origin or placement
-within the Entrada allow them to be grouped into three classes: (1)
-vertical arches formed in the Slick Rock Member alone or in the Slick
-Rock and Moab Members, (2) vertical arches formed mainly in the Slick
-Rock Member but partly in, and with the aid of, the incompetent
-underlying Dewey Bridge Member, and (3) horizontal arches, or so-called
-pothole arches, formed from the union of a vertical pothole and a
-horizontal cave. Hereinafter, the three members will be referred to
-alone, without reference to the Entrada.
-
-    [Illustration: “BABY ARCH,” just southwest of Sheep Rock in
-    Courthouse Towers area. For details, see text. (Fig. 15)]
-
-Before giving examples of arches in each of the three classes, it is
-appropriate to remark that the arches and other erosion forms in the
-park represent but a fleeting instant in geologic time. Many of the
-pinnacles or piles of rock may be the broken remains of former arches,
-and many of the arches we see may be gone tomorrow, next year, or a few
-hundreds of years and, certainly, before many thousands of years. On the
-other hand, many new arches will form by the processes described above
-as the geologic clock ticks on.
-
-    [Illustration: BROKEN ARCH, reached by a ½-mile trail leading
-    northward across field that separates Fiery Furnace from Devils
-    Garden. White thin-bedded unit at top is the Moab Member, which
-    rests upon the massive salmon-colored Slick Rock Member. Opening is
-    59 feet wide and 43 feet high. (Fig. 16)]
-
-
-                           Examples of Arches
-
-Tunnel Arch (fig. 14) is a good example of an arch eroded entirely
-within the massive Slick Rock Member. Just southwest of Sheep Rock (fig.
-31) is an unnamed opening in the lower part of the Slick Rock Member
-which I call “Baby Arch,” because it is one of the newest ones visible
-from the park road (fig. 15). It is only 25½ feet wide and 14 feet high
-and penetrates a wall 14 feet thick. Note that the breakthrough probably
-began along the prominent recessed bedding plane at the base of the
-arch. Its youthfulness is also indicated by the sharp, angular breaks in
-the ceiling and by the pile of freshly fallen rocks. Some visitors have
-asked park personnel why they have not cleared away such debris! Despite
-its youthfulness, the ceiling has already taken on the shape of an arch.
-
-Broken Arch (fig. 16) was formed near the top of the Slick Rock Member
-and is strengthened and protected by the more resistant overlying Moab
-Member, which forms the upper half of the span. The crest is only 6 feet
-thick at the thinnest point and is not broken as the name seems to
-imply.
-
-Double Arch (fig. 17), “one” of the most beautiful in the park, is in
-The Windows section near the east end of the road. The southeast arch,
-which is 160 feet wide and 105 feet high, is the second largest in the
-park, but the west arch measures only 60 feet wide and 61 feet high. In
-common with most arches in The Windows section, these two arches of the
-Slick Rock Member rest upon bases of the weak, easily eroded Dewey
-Bridge Member. More rapid erosion of the Dewey Bridge undercut the
-arches and hastened their development.
-
-    [Illustration: DOUBLE ARCH, in The Windows section. (Fig. 17)]
-
-    [Illustration: PROBABLE STEPS IN FORMATION OF POTHOLE ARCH. _A_,
-    Original pothole probably formed in relatively level bed of
-    sandstone, such as this one, which is in an older rock unit—the
-    White Rim Sandstone Member of the Cutler Formation, a unit not
-    present in Arches. This pothole, which contains 4 feet of water, is
-    in nearby Canyonlands National Park (Lohman, 1974, fig. 17), just
-    north of the edge of the White Rim, about 4½ miles north of the
-    confluence of the Green and Colorado Rivers. Photograph by E. N.
-    Hinrichs. _B_, Pothole is being deepened by solution while cliff is
-    receding toward pothole by weathering. _C_, As erosion continues,
-    pothole and cave in cliff face are growing deeper. _D_, Pothole Arch
-    formed by union of vertical pothole and horizontal cave. _E_,
-    Telephoto view of Pothole Arch from park road near stop 14. Visible
-    span is 90 feet across and 30 feet high. (Fig. 18)]
-
-    [Illustration: Fig. 18 B]
-
-    [Illustration: Fig. 18 C]
-
-    [Illustration: Fig. 18 D]
-
-    [Illustration: Fig. 18 E]
-
-The cause of the wavy bedding in the Dewey Bridge Member, as shown in
-figure 17 but as better shown in the frontispiece, is not known for sure
-but generally is regarded to be the result of irregular slumping during
-or just after deposition of the sediments in a body of water, caused by
-the weight of overlying sediments.
-
-The last example I shall take up is Pothole Arch (fig. 18), which
-differs from all the other examples in that this arch is roughly
-horizontal rather than vertical. Most park visitors, including me, were
-not aware of this interesting feature until after publication of the
-pamphlet “The Guide to an Auto Tour of Arches National Park,” which, as
-previously noted, may be purchased at the Visitor Center. Pothole Arch
-caps a ridge high above the road half a mile northwest of Garden of
-Eden, so only those who happened to look up at the right place were
-aware of its existence.
-
-A different mode of origin than that given in the caption for figure 18
-is depicted on a poster in the Visitor Center, which shows the pothole
-being formed by a waterfall having an apparent flow rate of several
-cubic feet per second. Potholes can be formed in this manner in places
-where sufficient streamflow is available, either continuously or
-following rainstorms, but I believe the process depicted in figure 18 is
-a more likely mode of origin for Pothole Arch.
-
-
-
-
-                          How to See the Park
-
-
-As aptly stated on a poster in the Visitor Center, how to see the park
-depends in part upon the question “How long can you stay?” Inasmuch as
-the park entrance and Visitor Center are beside a through U.S. Highway
-(163), many motorists first become aware of the park’s existence from
-the entrance sign, and some take time for at least a quick visit, such
-as a round trip to The Windows section, which can be made in an hour or
-so.
-
-For those who have or take more time and are able to walk at least short
-distances, a visit of 1 or 2 days is a very rewarding experience.
-Others, particularly avid shutterbugs and those with camping gear,
-profitably spend from several days to a week or more and hike all or
-most of the trails.
-
-Regardless of how long you plan to spend, I urge at least a brief stop
-at the Visitor Center, where excellent displays and a narrated slide
-show help materially in conveying just what the park has to offer. At
-the counter you can purchase a copy of “The Guide to an Auto Tour of
-Arches National Park,” which explains the views from each of 25 numbered
-stops along the park road, as well as other reports describing arches or
-other parks and monuments.
-
-The park is open the year round, but, like most high deserts, it gets
-rather hot in the summer and cold enough in the winter for occasional
-snows and is sometimes closed temporarily because of heavy snowfall. The
-weather generally is ideal during the spring and fall. Even though
-summer daytime temperatures may exceed 100°F (37.8°C) and slow down
-hikers, the nights are cool enough for comfortable sleeping beneath
-ample covers.
-
-Before beginning our trip through the park proper, let us consider a
-beautiful part many people fail to realize actually belongs to the
-park—the Colorado River canyon forming the southeastern boundary.
-
-    [Illustration: Petroglyph figure]
-
-
-
-
-A Trip Through The Park
-
-
-                         Colorado River Canyon
-
-The southeastern boundary of the park for about 11 miles is the Colorado
-River, from the bridge on which U.S. Highway 163 crosses the river to a
-point upstream about half a mile below the mouth of Salt Wash.
-Illuminated night float trips down part of this reach are run during the
-summer, as noted on p. 16. Partly paved State Highway 128 follows the
-southeast side of the river for about 30 miles to Dewey Bridge, then
-goes northward about 15 miles to Cisco, where it connects with Highway
-I-70.
-
-The rocks of the Glen Canyon Group form the southernmost corner of the
-park, as shown in figure 19. About 2 miles northeast of the bridge, we
-cross the axis of the Courthouse syncline (fig. 9), which brings the
-Navajo Sandstone down nearly to river level, as shown in figure 20. The
-underlying Kayenta Formation is largely hidden by vegetation and
-alluvial deposits in this view.
-
-    [Illustration: GLEN CANYON GROUP, forming southernmost point of
-    park, as viewed across the Colorado River from State Highway 128
-    half a mile above Moab bridge carrying U.S. Highway 163. Massive
-    sandstone forming about the lower third of cliff is the Wingate
-    Sandstone, darker thin-bedded sandstones and mudstones forming
-    middle section of cliff comprise the Kayenta Formation, upper cliff
-    is the lower part of the Navajo Sandstone. Note that the saltcedar
-    (tamarisk), which lines both banks of the river, is in full bloom.
-    (Fig. 19)]
-
-    [Illustration: NAVAJO SANDSTONE CLIFFS, bordering west bank of
-    Colorado River in Courthouse syncline, from State Highway 128 about
-    2 miles above the Moab bridge. Note rounded domes at top of cliff.
-    (Fig. 20)]
-
-    [Illustration: MOUTH OF SALT WASH, viewed across Colorado River from
-    point on State Highway 128, 11 miles above Moab bridge. Dark cliffs
-    on upper right and left are of Wingate Sandstone capped by thin
-    protective cover of resistant sandstone beds of the Kayenta
-    Formation. In background Wingate is overlain by entire Kayenta
-    Formation and lower part of the Navajo Sandstone. Wingate is
-    underlain to river level by weathered slope of the Chinle Formation.
-    Water in Salt Wash is largely backwater from the bankfull river;
-    actual flow in wash generally is much less but at times reaches
-    flood proportions. (Fig. 21)]
-
-About 11 miles above the Moab bridge is the mouth of Salt Wash (fig. 1),
-as viewed from State Highway 128. (See fig. 21.) Seventeen miles above
-the bridge (east of area shown in fig. 1), we get an excellent view of
-the southeast end of the highly faulted Cache Valley anticline, as shown
-in figure 22. The background shown in the photograph formerly was the
-easternmost part of the former monument, but when the monument graduated
-to a park on November 16, 1971, this part of Cache Valley along with
-most of Dry Mesa was withdrawn from the park and put under the
-supervision of the Bureau of Land Management, also a part of the
-Department of the Interior.
-
-    [Illustration: SOUTHEAST END OF FAULTED CACHE VALLEY ANTICLINE,
-    viewed northwestward across Colorado River from a point on State
-    Highway 128, 17 miles above Moab bridge. High cliff of Wingate
-    Sandstone on left is capped by thin protective layer of the Kayenta
-    Formation. About upper third of slope below base of cliff is the
-    Chinle Formation, below which is the Moenkopi Formation extending to
-    high-water level. Note bent and broken beds on right. (Fig. 22)]
-
-As noted on page 16, part of “Run, Cougar, Run” was filmed just upstream
-from the irrigated field in the foreground of figure 22, in a wide part
-of the valley called Professor Valley (fig. 7). This valley and the
-Richardson Amphitheater on the southeast side of the river were named
-after a Professor Richardson who settled in the area in the 1880’s. The
-long abandoned townsite of Richardson was 1¼ miles due east from the
-point from which figure 22 was taken.
-
-
-                           Headquarters Area
-
-The junction of the park road with U.S. Highway 163 is shown at the
-lower left of figure 23, and the entrance station, Visitor Center,
-parking lot, and several buildings are seen at the lower right. Several
-residences for park personnel and other buildings are shown in figure
-25. As shown in the lower part of figure 23, the geology at the park
-entrance is rather complex, as the park boundary here is partly along
-the Moab fault and partly along a branch fault—both in the Seven
-Mile-Moab Valley anticline (fig. 7). The Moab fault extends
-northwestward from Moab for more than 30 miles (McKnight, 1940, p. 120,
-121, pl. 1).
-
-As shown in figure 23, soon after leaving the checking station the park
-road begins to ascend the first of several switchbacks, and cuts first
-into the Slick Rock Member, then the Dewey Bridge Member, and finally
-the Navajo Sandstone the rest of the way to and beyond the top of the
-hill.
-
-From points a mile or so up the hill may be seen interesting features in
-several directions.[5] The view to the southwest is shown in figure 23,
-to the west are the Three Penguins (fig. 24). A good view of the Moab
-Valley is had by looking southeastward (fig. 25). A well in the Navajo
-Sandstone at the base of the hill supplies water to all the residences
-and to the Visitor Center, where a drinking fountain and modern
-restrooms are available to the public. Storage is provided by a steel
-tank hidden in a ravine above the buildings shown in figure 25.
-
-To the north the wall of Entrada Sandstone is cut by a normal fault
-(fig. 6), as shown in figure 26.
-
-    [Illustration: FAULTED SEVEN MILE-MOAB VALLEY ANTICLINE. Top, View
-    toward the southwest from park road about 1 mile above entrance
-    station. Bottom, Geologic interpretation of photograph in part after
-    McKnight (1940, pl. 1). Moab fault and branch fault (both normal
-    faults, fig. 6) unite just beyond ridge of Slick Rock Member. Total
-    vertical displacement along both faults is about 2,500 feet. H.F.,
-    unnamed upper member of Hermosa Formation; M.F., Moenkopi Formation;
-    D, downthrown side of faults; U, upthrown side. Valley fill and
-    slope wash of recent (Holocene) age obscure faults and underlying
-    rocks. The original sequence of the rocks may be visualized by
-    placing the Navajo Sandstone, the upper part of which is exposed at
-    the lower right, on top of the Kayenta Formation, the lower few feet
-    of which cap and protect the cliffs of Wingate Sandstone in the
-    background. The Pacific Northwest (gas) Pipeline mentioned on page
-    15 is buried beneath the slice of the Moenkopi Formation between the
-    two faults, which accounts for the disturbed appearance of the rock.
-    (Fig. 23)]
-
-    [Illustration: Geologic interpretation of photograph]
-
-    [Illustration: THREE PENGUINS, viewed westward from park road about
-    1 mile above entrance station. Penguins are carved in massive Slick
-    Rock Member seen resting upon thin-bedded Dewey Bridge Member. (Fig.
-    24)]
-
-    [Illustration: MOAB VALLEY, viewed southeastward from park road
-    about 1 mile above entrance station. Moab fault in about middle of
-    valley, hidden beneath recent (Holocene) valley fill and slope wash,
-    separates unnamed upper member of Hermosa Formation just above U.S.
-    Highway 163 on right from Navajo Sandstone forming hills on left and
-    ledges in foreground. Park Service residences at base of hill. White
-    patch bordering Colorado River on northwest is tailings pile of
-    Atlas Corporation’s uranium mill. Moab and Spanish Valley are beyond
-    river, and south end of La Sal Mountains forms distant skyline.
-    (Fig. 25)]
-
-    [Illustration: FAULTED WALL OF ENTRADA SANDSTONE, north of park road
-    about 1 mile above entrance station. Fault is nearly vertical and
-    normal (fig. 6), but fault trace slopes steeply downward to right,
-    separating upthrown Slick Rock and Dewey Bridge Members on left from
-    downthrown Slick Rock Member on right. Light-colored rock in
-    foreground is Navajo Sandstone. Displacement probably does not
-    exceed 50 feet. (Fig. 26)]
-
-    [Illustration: PARK AVENUE, viewed to the north along trail. (Fig.
-    27)]
-
-
-                         Courthouse Towers Area
-
-About 2.3 miles from the entrance station is a turnoff and parking area
-at the south end of the Park Avenue trail (stop 2), which is about 1
-mile long and ends at another parking area 1.7 miles farther north. An
-interesting hike is best made from south to north in a downhill
-direction, and hikers generally meet the cars of relatives or friends
-awaiting them at the northern parking area. The trail begins in a canyon
-cut in the soft Dewey Bridge Member and walled by high fins of the Slick
-Rock Member (fig. 27), but farther north the canyon is floored by the
-bare Navajo Sandstone. The avenue was named from the resemblance of the
-east wall to a row of tall buildings. Atop the west wall, just to the
-left of the view in figure 27, are two balanced rocks (fig. 28). The one
-on the left, which resembles somewhat the head of an Egyptian queen, is
-offset to the right along a bedding plane, and this offset may have been
-caused by an earthquake.
-
-As we progress toward Courthouse Towers proper, lofty fins and monoliths
-lie mostly on our left, and to the right are fine distant views of the
-La Sal Mountains (stop 4). A general view of the Courthouse Towers is
-shown in figure 29, and closeups of two of the named rock sculptures—the
-Three Gossips and Sheep Rock—are shown in figures 30 and 31. Just beyond
-Sheep Rock, which some think resembles the Sphinx, we see “Baby Arch,”
-shown in figure 15.
-
-Five miles from the entrance station, the road crosses Courthouse Wash
-on a modern bridge (stop 6)—a distinct improvement over the two tracks
-in the sand we used in 1946. The Courthouse syncline, named after the
-wash, extends northwestward through here. (See figs. 8, 9, 20.) About a
-mile west of the bridge, Professor Stevens found another pothole arch. A
-mile and a half north of the bridge is stop 7, where attention is called
-in the booklet to the vast area of “petrified dunes” east of the road,
-which are simply dunelike exposures of the crossbedded Navajo Sandstone
-formed originally by the cementation of a vast area of sand dunes. My
-view of these was taken about 1 mile beyond the stop (fig. 32).
-
-    [Illustration: BALANCED ROCKS ON SOUTH WALL OF PARK AVENUE, at south
-    end of trail. (Fig. 28)]
-
-    [Illustration: COURTHOUSE TOWERS, viewed to the northwest from point
-    on park road about three-fourths of a mile northeast of the south
-    end of Park Avenue trail. Sandstone towers are Slick Rock Member
-    resting on Dewey Bridge Member, which also forms foreground. Three
-    Gossips at upper left, Sheep Rock just beyond. The Organ and Tower
-    of Babel are on right. (Fig. 29)]
-
-    [Illustration: THE THREE GOSSIPS, shown at upper left of figure 29.
-    (Fig. 30)]
-
-    [Illustration: SHEEP ROCK, shown on center-left skyline in figure
-    29. (Fig. 31)]
-
-West of the road between the petrified dunes and The Windows section,
-the Entrada Sandstone, particularly the Dewey Bridge Member, has been
-weathered into grotesque spires and pinnacles resembling the so-called
-“hoodoos and goblins” in Goblin Valley State Park, just north of
-Hanksville, Utah. Typical examples of “hoodoos and goblins” are shown in
-figure 33 (near stop 8). It seems reasonable to assume that some of
-these spires are the skeletal remains of former arch abutments. From
-here may be seen North and South Windows and Turret Arch on the skyline
-to the northeast (figs. 37-40).
-
-    [Illustration: PETRIFIED SAND DUNES, looking northeast from park
-    road 2.7 miles north of Courthouse Wash. The Navajo Sandstone was
-    once a huge sandpile of dunes laid down by winds during an arid
-    interval, so it is interesting to note that the irregularly
-    weathered sandstone once again resembles a pile of crossbedded
-    dunes. See also figure 35. (Fig. 32)]
-
-    [Illustration: “HOODOOS AND GOBLINS,” weathered from Dewey Bridge
-    Member, viewed northwest from park road about 2½ miles north of
-    Courthouse Wash. (Fig. 33)]
-
-
-                          The Windows Section
-
-The Windows section, one of the most beautiful parts of the park, once
-was the only readily accessible part of the former monument and is still
-the only collection of arches seen by many visitors who either do not
-have or do not take time to travel farther north. All the arches and
-erosion forms are on or near a high crest called Elephant Butte (Dane,
-1935, p. 126, 127), which separates Salt Valley from the Courthouse
-syncline. The ridge also marks the south edge of several minor
-anticlines and synclines termed by Dane the “Elephant Butte folds.”
-
-    [Illustration: EYE OF THE WHALE, one of several arches in Herdina
-    Park, just south of jeep trail about 2 miles northwest of Balanced
-    Rock. Cut in Slick Rock Member. Front opening is 60 feet wide and 27
-    feet high, but back opening is only 35 feet wide and 11 feet high.
-    Photograph by Professor Dale J. Stevens, Brigham Young University.
-    (Fig. 34)]
-
-Guarding the approach to The Windows section is Balanced Rock (stop 9).
-As shown in the frontispiece, it is accompanied on the right by another
-balanced rock and a third one may be seen in the distance. The original
-route to The Windows section, pioneered by Goulding, passed just north
-of Balanced Rock. Traces of the old road between here and the Garden of
-Eden parking area are still visible but no longer used. To the west,
-however, a part of the old road is the starting point of a jeep trail
-leading northwestward through Herdina Park to a point near Klondike
-Bluffs, where it joins the dirt road in Salt Valley (fig. 1). Visitors
-having four-wheel-drive vehicles may wish to drive at least as far as
-Eye of The Whale (fig. 34), which is about 2 miles northwest of Balanced
-Rock. There are several picnic tables at the beginning of this jeep
-trail, but no water.
-
-    [Illustration: INTRICATE CROSSBEDS IN NAVAJO SANDSTONE, on north
-    side of road between Garden of Eden and Cove of Caves. Red crest is
-    basal part of Dewey Bridge Member. (Fig. 35)]
-
-Just beyond Balanced Rock, a branch paved road turns eastward 2½ miles
-to the main parking lots in The Windows section. Between the Garden of
-Eden (stop 13) and Cove of Caves are spectacular exposures of the Navajo
-Sandstone showing the crossbedding typical of the original dunes (fig.
-35). Just east of the crossbedded Navajo Sandstone, shown in figure 35,
-we pass Cove Arch and Cove of Caves (stop 10) on the north side of the
-road (fig. 36).
-
-Just around the curve east of Cove of Caves is the first of two parking
-lots (stop 11) forming a one-way loop at the end of this branch of the
-road. From the loop may be seen the greatest concentration of readily
-accessible arches in the park, all of which are roofed by the Slick Rock
-Member and floored by the Dewey Bridge Member. Let us take the short
-paved trail from the upper lot to the southeast, where we come first to
-North Window (fig. 37). If we walk through this arch and climb the rock
-beyond (fig. 37 caption), we see one of the best views in the park (fig.
-38). A short walk south of North Window brings us to South Window (fig.
-39). The other side of this arch may be reached either by walking around
-the nearby southeast end of the fin or by walking through North Window.
-A short walk to the southwest brings us to Turret Arch—the one seen
-through North Window in figure 38. Figure 40 was taken from the
-southwest side of Turret Arch, viewed northeastward toward South Window,
-one corner of which appears at the left. Both North and South Windows
-may be seen in one photograph taken from points near Turret Arch.
-
-    [Illustration: COVE ARCH AND COVE OF CAVES, on north side of road
-    just west of Double Arch and Parade of Elephants. Arch at left and
-    three of the caves on right are roofed by Slick Rock Member and
-    floored by Dewey Bridge Member. Arch is 48½ feet wide and 34 feet
-    high. In time the caves will eat through the 30-foot-thick fin and
-    become arches. Note sharp contact between Dewey Bridge Member and
-    Navajo Sandstone. (Fig. 36)]
-
-    [Illustration: NORTH WINDOW, viewed to the northeast. Large rock
-    seemingly partly blocking left end of arch actually is the southeast
-    end of a fin some 50 feet or more beyond the arch, from which figure
-    38 was taken. Arch is 93 feet wide and 51 feet high. (Fig. 37)]
-
-From the lower parking lot (stop 12), a short walk by paved trail takes
-us to spectacular Double Arch, shown in figure 17. This arch is visible
-from the parking lot but is best seen and photographed from at or near
-the end of the trail. Looking westward from near the trail’s end, we see
-the Parade of Elephants, shown in figure 41. This feature is described
-on pages 16 and 17 of “The Guide to an Auto Tour of Arches National
-Park” as “whimsical stone statuary resembling a circus pachyderm parade.
-With tail in trunk, the elephants rumble toward you along a sandstone
-roadway.”
-
-Ribbon Arch, on the north side of Elephant Butte, is one of the most
-delicate ones in the park (fig. 1). Although it is 50 feet wide and 55
-feet high, the rock span is only 1½ feet wide and 1 foot thick.
-
-On the way back to the intersection with the main park road, we pass
-stop 14, from which may be seen Pothole Arch (fig. 18). One and one-half
-miles north of the intersection with the main road is the Panorama Point
-parking area (stop 15), which affords fine distant views of Salt and
-Cache Valleys and points beyond. A roadside exhibit portrays the gradual
-development of the Salt Valley anticline, which supplements my
-description on pages 27-32. A parking space a short distance farther
-down the hill (stop 16) provides good distant views of the Fiery
-Furnace. I tried several telephoto shots from this viewpoint, but
-preferred my closeup views, such as the one shown in figure 44.
-
-    [Illustration: LOOKING SOUTHWESTWARD THROUGH NORTH WINDOW, from fin
-    shown beyond left side of North Window in figure 37. Turret Arch
-    (fig. 40) is seen at right middle ground, south rim of Moab Valley
-    to left of arch, Colorado River canyon forms left skyline. (Fig.
-    38)]
-
-    [Illustration: SOUTH WINDOW, viewed toward northeast. Arch is 105
-    feet wide and 66 feet high. See text. (Fig. 39)]
-
-
-                           Delicate Arch Area
-
-Two and a half miles northeast of the road intersection near Balanced
-Rock, a gravelled side road leads northeastward to several points of
-considerable interest. The photograph in figure 11 was taken from this
-side road about half a mile northeast of the intersection. About 2 miles
-to the northeast, just beyond Salt Valley Wash, is a parking area (stop
-17) at the beginning of the trail past Wolfe’s Bar-DX Ranch (fig. 3) to
-famed Delicate Arch, which is featured on the front cover. Although the
-trail to the arch is only 1½ miles long, it crosses several hills at the
-outset, then climbs 500 feet, mostly on bare Entrada Sandstone, so is
-considered quite strenuous, particularly in hot weather. The Park
-Service advises hikers to carry water. The Walt Disney crew, cameras,
-gear, cougars, and all climbed this trail in the hottest part of the
-summer of 1971 (see p. 16), while my wife and I were working in the
-vicinity. Visitors who do not wish to make the hike may get a distant
-view of Delicate Arch by driving to a parking area (stop 18) 1.3 miles
-farther east.
-
-    [Illustration: TURRET ARCH, viewed northeast toward South Window,
-    part of which is visible on left. Small opening on right is visible
-    also in figure 38. Largest arch is 39 feet wide and 64 feet high;
-    smaller one is 12 feet wide and 13 feet high. A still smaller one,
-    not visible in the photograph, is 8 feet wide and only 4½ feet high.
-    (Fig. 40)]
-
-    [Illustration: PARADE OF ELEPHANTS, viewed west from end of trail to
-    Double Arch. Two elephants are on right, one on left. (Fig. 41)]
-
-After leaving Wolfe’s Ranch, the trail to Delicate Arch crosses Salt
-Wash on a suspension foot bridge (fig. 42). Just beyond the bridge, a
-short walk to the left (north) leads to the Ute petroglyphs shown in the
-lower photograph of figure 2. The most difficult part of the trail, on
-bare sandstone, is marked by cairns of stones placed at sufficient
-intervals to keep hikers from losing the barely visible trail. When the
-summit finally is reached and the last corner rounded, one suddenly sees
-perhaps the most sublime view in the park—famed Delicate Arch, framing
-part of the La Sal Mountains beyond (fig. 43). This graceful arch and
-mighty Landscape Arch (fig. 53) were considered to be in serious
-jeopardy during the era of sonic booms, but hopefully this danger now is
-past. (See p. 16-17.)
-
-It may be of interest to shutterbugs that professional photographer Hal
-Rumel lugged an 8- × 10-inch camera plus a heavy tripod and accessories
-up the steep trail to get the excellent photograph of Delicate Arch
-shown in figure 43. The late afternoon sun intensified the red somewhat,
-but my shots made earlier in the day using both 4- × 5-inch and 35-mm
-equipment resulted in unwanted shadows, even though the salmon color of
-the Slick Rock Member was more nearly normal.
-
-After leaving the junction with the side road, the main park road
-traverses slices of vertical strata squeezed between faults along the
-north side of Salt Valley, then gradually climbs out of the valley for
-about 2 miles to a parking area (stop 19), from which good views are had
-of the southeast end of Salt Valley and of the grabens in the west end
-of Cache Valley. (See fig. 11.)
-
-    [Illustration: Petroglyph figure]
-
-    [Illustration: SUSPENSION FOOT BRIDGE ACROSS SALT WASH, in front of
-    Wolfe’s cabin at beginning of Delicate Arch trail. (Fig. 42)]
-
-    [Illustration: DELICATE ARCH, from end of trail 1½ miles above
-    Wolfe’s Ranch. The opening is 33 feet wide and 45 feet high. The
-    left abutment is only 5 feet wide at the narrowest point. The arch
-    is carved near the top of the Slick Rock Member, and the top of the
-    span, 19 feet thick, is capped by a few feet of the more resistant
-    Moab Member, as is Broken Arch (fig. 16). Photograph by Hal Rumel,
-    Salt Lake City. (Fig. 43)]
-
-
-                             Fiery Furnace
-
-About half a mile farther uphill is a parking area for viewing the
-southeastern part of the Fiery Furnace (stop 20), a vast array of
-towering fins and pinnacles of the reddish Slick Rock Member separated
-by narrow slots, vaguely resembling flames shooting skyward. The view of
-the Fiery Furnace in figure 44 was taken about 1 mile farther up the
-hill. It is not difficult to get lost among this myriad of fins and
-narrow slots, so ranger-guided tours are conducted during the summer.
-
-About 1 mile farther northwest is a parking area (stop 23) from which a
-short walk to the north end of Fiery Furnace leads to a narrow slot
-between high fins (fig. 45), along which a short sandy trail leads to a
-recess along the southwest wall containing Sand Dune Arch (fig. 46).
-This hidden arch receives sunshine only near the middle of the day and
-is a delightful, shady place to rest.
-
-From the entrance to the slot leading to Sand Dune Arch, a trail goes
-half a mile north across an open field to Broken Arch, shown in figure
-16. This field, which separates the Fiery Furnace and Devils Garden
-areas, is seen from the air in figure 12.
-
-    [Illustration: Petroglyph figure]
-
-    [Illustration: FIERY FURNACE, viewed northwest along park road about
-    1 mile northwest from stop 20. Fins and spires are of the jointed
-    Slick Rock Member (fig. 12), but the top of the Dewey Bridge Member
-    is seen to the right of the curve in the road. (Fig. 44)]
-
-    [Illustration: TRAIL TO SAND DUNE ARCH, looking northwest away from
-    arch, between towering fins of Slick Rock Member, at northwest end
-    of Fiery Furnace. Southeast end of Devils Garden in distance. (Fig.
-    45)]
-
-    [Illustration: SAND DUNE ARCH, in recess along southwest wall of
-    narrow slot shown in figure 45. Slick Rock Member. (Fig. 46)]
-
-
-                    Salt Valley and Klondike Bluffs
-
-Before proceeding to the end of the paved road, let us take an
-unimproved side road, which turns south about a third of a mile beyond
-the last stop, in order to see more of Salt Valley and to visit Klondike
-Bluffs in the northwestern part of the park. After descending 2.3 miles
-of winding road we reach the normally dry bed of Salt Valley Wash, and
-turn abruptly to the northwest. For the next three-fourths of a mile the
-“road” is simply two tracks in the loose, sandy bed of the wash, which
-obviously should not be travelled when flooded or when there is even a
-hint of rain. In dry weather, however, this road may be travelled by
-ordinary passenger car. This stretch of the wash cuts through an
-intruded block of the Paradox Member of the Hermosa Formation consisting
-mainly of gray and brown gypsum, the common salt having been dissolved
-out by ground water. Such an intrusive block of salt-bearing rock is
-known to geologists as a diapir—not to be confused with the garment
-(diaper) worn by infants.
-
-From here on the road traverses a rather uninteresting stretch of valley
-north of Salt Valley Wash. Eleven miles from the starting point, the
-road reaches an intersection from which a side road leads southwestward
-three-fourths of a mile to a parking area at the foot of Klondike
-Bluffs, which form the south side of Salt Valley. From here, one may
-make a strenuous hike over a primitive trail about 1½ miles long to
-beautiful Tower Arch (fig. 47).
-
-The valley road continues northwestward from the intersection to and
-beyond the northwest end of the park and connects with roads to Crescent
-Junction, Thompson, and the Yellow Cat mining district, north of the
-park (p. 14).
-
-Let us return to the paved road and continue our tour of the park.
-
-
-                             Devils Garden
-
-Turning left (northwest) at the intersection with the paved park road,
-we enter Devils Garden—another large maze of towering red fins separated
-by narrow slots, which resembles the Fiery Furnace. After a third of a
-mile, we reach stop 24 and walk 100 feet or more to the north for a good
-view of Skyline Arch (fig. 48). This arch is very appropriately named,
-as it forms the skyline viewed either from the road on the south or from
-the campground on the north, from points south of the amphitheater. Less
-well known is the fact that Skyline Arch is clearly visible to the naked
-eye or through binoculars from stretches of Highway I-70 (or old U.S.
-Highways 6 and 50) about 11 miles to the north. Most arches and other
-erosion forms do not change appearance much from day to day or year to
-year, but some, like “Baby Arch” (fig. 15), show evidence of relatively
-recent origin. In November 1940 (Abbey, 1971, p. 42) Skyline Arch
-suddenly doubled in size by the fall of a large rock that occupied what
-is now the northwest half of the arch. Photographs taken before and
-after this event appear on pages 24 and 25 of the road guide and also in
-the museum at the Visitor Center.
-
-    [Illustration: TOWER ARCH, on Klondike Bluffs, viewed eastward. Arch
-    is in Slick Rock Member but tower on left, after which arch was
-    named, is capped by a protective layer of the resistant Moab Member.
-    Opening is 88 feet wide and 43 feet high. Photograph by Robert D.
-    Miller. (Fig. 47)]
-
-    [Illustration: SKYLINE ARCH, viewed north from point about 100 feet
-    north of stop 24, in Slick Rock Member. Although fins are vertical,
-    note that the strata seem to dip about 15° to the right, although
-    the actual dip is to the northeast. (See fig. 50.) (Fig. 48)]
-
-Another half mile brings us to a one-way (to right) loop at the end of
-the park road. Just beyond the beginning of the loop is a parking lot
-and very attractive picnic area containing several picnic tables shaded
-by piñon pines at the foot of a towering red fin of the Slick Rock
-Member. Just north of this picnic ground, a paved side road leads
-eastward into a truly beautiful, well-equipped campground comprising
-both back-in and drive-through campsites for trailers, campers, or
-tents; three pairs of modern restrooms, hydrants, and drinking
-fountains; and an amphitheater, where illustrated campfire talks are
-given nightly during the summer. The east end of the campground is shown
-in figure 49.
-
-    [Illustration: CAMPGROUND IN DEVILS GARDEN, viewed northwestward
-    across turn-around at southeastern end. (Fig. 49)]
-
-Devils Garden in general and the campground in particular are on the
-crest of a ridge separating Salt Valley to the southwest from the Sagers
-Wash syncline to the northeast, which lies north of Yellow Cat Flat and
-north of the area shown in figure 1. From the higher parts of the
-campground striking views are to be had toward the north and northeast,
-particularly late in the afternoon, as shown in figure 50.
-
-    [Illustration: VIEW NORTH FROM CAMPGROUND, in late afternoon.
-    Reddish Slick Rock Member capped by light-colored Moab Member are
-    seen dipping northeastward toward Sagers Wash syncline. Book Cliffs,
-    north of Thompson, are 16 miles north on left skyline. (Fig. 50)]
-
-In about the middle of the one-way loop at the end of the park road is a
-well that supplies water to the campground from early in the spring
-until the return of freezing weather late in the fall. The well, which
-was drilled in 1962 to a depth of 900 feet, obtains a small amount of
-water from the Wingate Sandstone. No water was found in the overlying
-Navajo and Entrada Sandstones because of the pronounced dip of the rocks
-toward the northeast, which allows any water in these rocks to drain
-northeastward (Ted Arnow, written commun., 1963). Water from this well
-is pumped to a steel tank in a high part of the campground, whence it
-flows by gravity to the three sets of restrooms.
-
-    [Illustration: SOUTHEASTERN PART OF DEVILS GARDEN TRAIL, viewed
-    northwestward. Narrow slot between fins of Slick Rock Member
-    indicates local spacing of joints. (Fig. 51)]
-
-At the northwest end of the one-way loop is a large parking area for use
-by people hiking the Devils Garden trail. This trail leads to seven of
-the most interesting arches in the park, all of which are in the Slick
-Rock Member, and there are many more farther to the northwest. The
-approximate distances to the seven arches are given in the paragraphs
-that follow. The trail is paved for about 1 mile as far as Landscape
-Arch (fig. 53), but from there to Double O Arch (fig. 56) the trail is
-primitive, and the Park Service recommends rubber soles as part of the
-trail is on bare sandstone. For these reasons, many visitors hike only
-as far as Landscape Arch.
-
-    [Illustration: PINE TREE ARCH, viewed northeastward. Opening is 46
-    feet wide and 48 feet high. Fin is 30 feet thick. (Fig. 52)]
-
-Much of the trail, particularly the first part, lies in a narrow slot
-between fins of the Slick Rock Member, as shown in figure 51. After
-about half a mile, a side trail to the north leads to a Y, the
-right-hand fork of which goes to Tunnel Arch (fig. 14). The left-hand
-fork leads to Pine Tree Arch, obviously named for the piñon pine framed
-by this arch (fig. 52).
-
-At the end of the improved part of the trail, we reach Landscape Arch
-(fig. 53), claimed by the Park Service to be the longest known natural
-arch in the world. According to Ouellette (1958) it is 291 feet long and
-118 feet high, but Professor Stevens’ measurements indicate it to be 287
-feet long and 106 feet high. At its thinnest point on the right, the
-span is only 11 feet wide and 11 feet thick. In 1958 three young men
-made what was claimed to be the second known ascent of Landscape Arch,
-using ropes and other climbing gear, after which they walked across
-(Ouellette, 1958). This crossing was made with the permission of a park
-ranger, but such permission is no longer given, for the safety of both
-the arch and of would-be climbers.
-
-Wall Arch is about a quarter of a mile beyond the end of the improved
-part of the trail, and another three-fourths mile brings us to Navajo
-Arch (fig. 54) and Partition Arch (fig. 55). A distant view of Partition
-Arch may be had just before reaching Landscape Arch. Part of the
-remaining trail to Double O Arch (fig. 56) is on the top of a low
-sandstone fin, in part between somewhat higher fins and in part above
-lower slots.
-
-    [Illustration: LANDSCAPE ARCH, viewed southwestward from near end of
-    improved part of Devils Garden trail. Note that ground beneath arch
-    is covered by slope wash and near the middle with what appears to be
-    a small landslide. Slick Rock Member here is more nearly buff than
-    salmon colored, because of a smaller content of iron oxide. Fresh
-    breaks and angular blocks of stone at right abutment indicate
-    relatively recent rock falls. See text for size. (Fig. 53)]
-
-    [Illustration: NAVAJO ARCH, viewed northeastward from a branch of
-    Devils Garden trail. One of few arches having a flat soil-covered
-    floor. Opening is 40½ feet wide. Photograph by National Park
-    Service. (Fig. 54)]
-
-Beautiful Double O Arch (fig. 56) is at the end of the Devils Garden
-trail about 2½ miles northwest of the trailhead. About half a mile
-northwest of the trail’s end is a prominent landmark called Dark Angel
-(fig. 57), which is visible in figure 12 and from the unimproved road in
-Salt Valley.
-
-    [Illustration: PARTITION ARCH, viewed southwestward from near Devils
-    Garden trail. Arch frames part of south wall of Salt Valley and, on
-    skyline, mesas south of Moab Valley. Opening is 27½ feet wide and 26
-    feet high. A smaller opening to the right measures 8½ feet wide and
-    8 feet high. Photograph by Dawn E. Reed. (Fig. 55)]
-
-    [Illustration: DOUBLE O ARCH, viewed about north from northwest end
-    of Devils Garden trail. Large opening is 71 feet wide and 45 feet
-    high; small one at lower left is 21 feet wide and 11 feet high. Span
-    of large opening is 11 feet wide and 6 feet thick. Arch frames a
-    part of the Book Cliffs about 14 miles to the north. Photograph by
-    Hildegard Hamilton, Flagstaff, Ariz. (Fig. 56)]
-
-    [Illustration: DARK ANGEL, a shaft of the Slick Rock Member that is
-    an erosional remnant of a once high, narrow fin. About one-half mile
-    northwest of Double O Arch. Photograph by National Park Service.
-    (Fig. 57)]
-
-    [Illustration: “INDIAN-HEAD ARCH,” in upper Devils Garden. Arch and
-    most of head are in Slick Rock Member, top of head is basal part of
-    Moab Member. Opening is 4 feet wide and 4½ feet high. Photograph by
-    Professor Dale J. Stevens, Brigham Young University. (Fig. 58)]
-
-    [Illustration: GEOLOGIC TIME SPIRAL, showing the sequence, names,
-    and ages of the geologic eras, 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
-    Precambrian Era 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 Paleozoic Era. (Fig. 59)]
-
-
-
-
-                             GEOLOGIC TIME
-                          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!
-
-Professor Stevens found 14 arches in what he called upper Devils Garden,
-northwest of Double O Arch, and two arches in the northwesternmost
-extension of the park known as Eagle Park (fig. 1). One of the unnamed
-arches in upper Devils Garden is shown in figure 58. I am tentatively
-calling it “Indian-Head Arch,” because of the rather obvious
-resemblance.
-
-This ends our journey through Arches National Park, but there remains
-for consideration a summary of the principal geologic events leading to
-the formation of this beautiful part of the Colorado Plateau and a brief
-comparison with the geology of other national parks and monuments on the
-Plateau.
-
-
-
-
-                      Summary of Geologic History
-
-
-Having finished our geologic trip through Arches National Park, let us
-see how the arches and other features fit into the bigger scheme of
-things—the geologic age and events of the Earth as a whole, as depicted
-in figure 59. As shown in figure 4, the rock strata still preserved in
-the park range in age from Pennsylvanian to Cretaceous, or from about
-300 million to 100 million years old—a span of about 200 million years.
-This seems an incredibly long time, until one notes that the earth is
-some 4.5 billion years old, and that our rock pile is but 1/23 or 4½
-percent of the age of the Earth as a whole. Thus, in figure 59, the
-rocks exposed in the park occupy only about the left half of the top
-whorl of the spiral.
-
-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 to about 250 million years, or nearly a full whorl of the
-spiral.
-
-Deep tests for oil and gas tell us that much older rocks underlie the
-area, and we have seen that some of these played a part in shaping the
-park we see today. In addition to the Precambrian igneous and
-metamorphic rocks, there is about 2,000 feet of Paleozoic sedimentary
-rocks older than the Pennsylvanian Paradox Member of the Hermosa
-Formation, most of which was laid down in ancient seas. This includes
-strata of Cambrian, Ordovician, Devonian, Mississippian, and
-Pennsylvanian ages (fig. 59). There are some gaps in the rock record
-caused by temporary emergence of the land above sea level and erosion of
-the land surface before the land again subsided below sea level so that
-deposition could resume. Silurian rocks are absent, presumably because,
-here, the Silurian Period was dominated by erosion rather than
-deposition.
-
-While Pennsylvanian and Permian rocks were being laid down in and
-southwest of the park, a large area to the northeast, called by
-geologists the Uncompahgre Highland (because it occupied the same
-general area as part of the present Uncompahgre Plateau), rose slowly
-above sea level. Whatever Paleozoic rocks were on this rising land plus
-part of the underlying Precambrian rocks were eroded and carried by
-streams into deep basins to the northeast and southwest. Thus, while
-some marine or near-shore deposits were being laid down in and south of
-the park, thousands of feet of red beds were being laid down by streams
-between the park and what is now the Uncompahgre Plateau. During part of
-Middle Pennsylvanian time, a large area, including the park, known as
-the Paradox basin, was alternately connected to or cut off from the sea,
-so that the water was evaporated during cutoff periods and replenished
-during periods when connection with the sea resumed. In these huge
-evaporation basins were deposited the salt and gypsum plus some potash
-salts and shale that now make up the Paradox Member of the Hermosa
-Formation.
-
-Arches National Park contains four northwesterly trending major
-folds—the Salt Valley and Cache Valley salt anticlines, the Courthouse
-syncline, and the faulted Moab-Seven Mile anticline, which forms the
-southwestern border. How these folds were formed was explained on pages
-27-32. The history of their growth, however, was a long one that began
-about 300 million years ago in the Pennsylvanian and ended about 50
-million years ago in the early Tertiary. The growth of these folds
-occurred in two stages. The first stage, which involved the development
-of the salt cores of the anticlines, ended in the Jurassic with the
-beginning of Morrison time; the second stage, which involved additional
-folding that intensified the magnitude and shape of existing folds,
-occurred in the early Tertiary and was followed later by collapse of the
-salt anticlines. The formation and collapse of the Salt Valley and Cache
-Valley anticlines was accompanied by pronounced jointing (fig. 12),
-which allowed differential erosion to produce the tall fins in which the
-arches were formed.
-
-The old Uncompahgre Highland continued to shed debris into the bordering
-basins until Triassic time, when it began to be covered by a veneer of
-red sandstone and siltstone of the Chinle Formation (Lohman, 1965). The
-area remained above sea level during the Triassic Period and most, if
-not all, of the Jurassic Period, although the Jurassic Carmel Formation
-was laid down in a sea that lay just to the west.
-
-Late in the Cretaceous Period a large part of Central and Southeastern
-United States, including the eastern half of Utah, sank beneath the sea
-and received thousands of feet of mud, silt, and some sand that later
-compacted into the Mancos Shale. This formation, as well as all younger
-and some older strata, has long since been eroded from most of the park
-area, but a little of the Mancos is preserved in the Cache Valley graben
-(fig. 11), and the entire Mancos Shale and younger rocks are present in
-adjacent areas, such as the Book Cliffs north of Green River, Crescent
-Junction, and Cisco (figs. 7, 50, 56).
-
-The land rose above the sea at about the close of the Cretaceous and has
-remained above ever since, although inland basins and lakes received
-sediment during parts of the Tertiary Period. Compressive forces in the
-Earth’s crust produced some gentle folding of the strata at the close of
-the Cretaceous, but more pronounced folding and some faulting occurred
-during the Eocene Epoch, when most of the Rocky Mountains took form.
-During the Miocene Epoch igneous rock welled up into older rocks to form
-the cores of the nearby La Sal, Abajo, and Henry Mountains. Additional
-uplift and some folding occurred in the Pliocene and Pleistocene Epochs.
-
-Much of the course of the Colorado River was established during the
-Miocene Epoch, with some additional adjustments in the late Pliocene and
-early Pleistocene Epochs (Hunt, C. B., 1969, p. 67). Erosion during much
-of the Tertiary Period and all of the Quaternary Period plus some
-sagging and breaking of the crest of the anticlines, brought on by
-solution and lateral squeezing of salt beds beneath the Moab-Seven Mile,
-Salt Valley, and Cache Valley anticlines, combined to produce the
-landscape as we now see it.
-
-The Precambrian rocks beneath the area are about 1.5 billion years old;
-so an enormous span of time is represented by the rocks and events in
-and beneath Canyonlands National Park.
-
-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. 59).
-
-Dinosaur N.M., with exposed rocks ranging in age from Precambrian to
-Cretaceous, covers the greatest time span (nearly 2 billion years), but
-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. and N.M. are next, with rocks ranging in age
-from Precambrian through Permian (excluding the Quaternary lava flows in
-the N.M.), but here there 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 Precambrian age with only
-a veneer of much younger rocks, obviously has but one star in its cast.
-Colorado N.M. contains rocks ranging from Precambrian to
-Cretaceous—equal to Dinosaur in this respect, but Colorado is unique in
-that all the 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.
-
-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 (fig. 19), 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, despite the fact that
-the latter is the type locality of the entire Glen Canyon Group. 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. 59), 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 same ancient people who once dwelt in Arches N.P. and
-nearby areas.
-
-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 volcanoes 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. Don’t 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.
-
-
-
-
-                           Additional Reading
-
-
-Many reports covering various aspects of the area have been cited in the
-text by author and year, and these plus a few additional ones are listed
-in “Selected References.” A few works of general or special interest
-should be mentioned, however.
-
-Between 1926 and 1929 the entire area now included in the park was
-mapped geologically in classic reports by Dane (1935) and by McKnight
-(1940). These men and their field assistants mapped the area by use of
-the plane-table and telescopic alidade without benefit of modern
-topographic maps or aerial photographs, except for topographic maps of
-the narrow stretch along the Colorado River mapped under the direction
-of Herron (1917). Only small sections could be reached by automobile, so
-nearly all the area was traversed using horses and mules or by hiking.
-This work plus mapping done in nearby areas to the south and to the
-north (Stokes, 1952) during the uranium boom of the mid-fifties was used
-by Williams (1964) in compiling a geologic map of the Moab quadrangle at
-a scale of 1:250,000.
-
-Several early reports on the Colorado River and its potential
-utilization contain a wealth of information and many fine photographs,
-including two by La Rue (1916, 1925) and one by Follansbee (1929).
-
-You may be interested in brief accounts of the geology of other national
-parks and monuments, or other areas of special interest, such as the
-reports on the Uinta Mountains by Hansen (1969), Mount Rainier by
-Crandell (1969), Yellowstone National Park by Keefer (1971), and ones by
-me on Colorado National Monument (Lohman, 1965) and Canyonlands National
-Park (1974).
-
-For those who wish to learn more about the science of geology, I suggest
-the textbook by Gilluly, Waters, and Woodford (1968).
-
-
-
-
-                            Acknowledgments
-
-
-I am greatly indebted to Bates Wilson, former Superintendent, and to
-former Assistant Superintendent Joe Carithers, for their splendid
-cooperation in supplying data and information; to Chuck Budge, former
-Chief Ranger; Dave May, Assistant Chief of Interpretation and Resource
-Management; Joe Miller, former Maintenance Engineer; Bob Kerr, new
-Superintendent; Maxine Newell, Park Historian and member of the staff at
-Arches National Park; Jerry Banta, former Park Ranger at Arches; and
-Carl Mikesell, Park Ranger at Arches, for their many favors.
-
-I am grateful to several colleagues and friends for the loan of
-photographs, for geologic help and data, and for reviewing this report.
-I am also deeply grateful to my wife, Ruth, for accompanying me on all
-the fieldwork and for her help and encouragement.
-
-
-
-
-                          Selected References
-
-
-  Abbey, Edward, 1971, Desert solitaire, a season in the wilderness: New
-          York, Ballantine Books, 303 p.
-  Baker, A. A., 1933, Geology and oil possibilities of the Moab
-          district, Grand and San Juan Counties, Utah: U.S. Geol. Survey
-          Bull. 841, 95 p.
-  Baker, Pearl, 1971, The Wild Bunch at Robbers Roost: New York,
-          Aberlard-Schuman, 224 p.
-  Beckwith, Frank, 1934, A group of petroglyphs near Moab, Utah: Santa
-          Fe, N. Mex., El Palacio, v. 36, p. 177-178.
-  Breed, Jack, 1947, Utah’s arches of stone: Natl. Geog. Mag., p.
-          173-192, August.
-  Case, J. E., and Joesting, H. R., 1972, Regional geophysical
-          investigations in the central Colorado Plateau: U.S. Geol.
-          Survey Prof. Paper 736, 34 p.
-  Cater, F. W., 1970, Geology of the salt anticline region in
-          southwestern Colorado: U.S. Geol. Survey Prof. Paper 637, 80
-          p.
-  —— 1972, Salt anticlines within the Paradox Basin, _in_ Geologic atlas
-          of the Rocky Mountain region, United States of America:
-          Denver, Colo., Rocky Mtn. Assoc. of Geologists, p. 137, 138,
-          fig. 4.
-  Cleland, H. F., 1910, North American natural bridges, with a
-          discussion of their origins: Geol. Soc. America Bull., v. 21,
-          p. 313-338.
-  Crandell, D. R., 1969, The geologic story of Mt. Rainier: U.S. Geol.
-          Survey Bull. 1292, 43 p.
-  Dane, C. H., 1935, Geology of the Salt Valley anticline and adjacent
-          areas, Grand County, Utah: U.S. Geol. Survey Bull. 863, 184 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.]
-  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., 1968, Principles
-          of geology [3d ed.]: San Francisco, W. R. Freeman & Co., 685
-          p.
-  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.
-  Herron, W. R., 1917, Profile surveys in the Colorado River Basin in
-          Wyoming, Utah, Colorado, and New Mexico: U.S. Geol. Survey
-          Water-Supply Paper 396, 6 p., 43 pls.
-  Hite, R. J., 1972, Pennsylvanian rocks, _in_ Geologic atlas of the
-          Rocky Mountain region, United States of America: Denver,
-          Colo., Rocky Mtn. Assoc. of Geologists, p. 133-137.
-  Hite, R. J., and Lohman, S. W., 1973, Geologic appraisal of Paradox
-          basin salt deposits for waste emplacement: U.S. Geol. Survey
-          open-file report, 75 p.
-  Hunt, Alice, 1956, Archeology of southeastern Utah, _in_ Geology and
-          economic deposits of east-central Utah: Salt Lake City,
-          Intermountain Assoc. of Petroleum Geologists, 7th Ann. Field
-          Conf., p. 13-18.
-  Hunt, C. B., 1956, Cenozoic geology of the Colorado Plateau: U.S.
-          Geol. Survey Prof. Paper 279, 99 p.
-  —— 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, Special Issue no. 2, p. 10-15.
-  Joesting, H. R., Case, J. E., and Plouff, Donald, 1966, Regional
-          geophysical investigations of the Moab-Needles area, Utah:
-          U.S. Geol. Survey Prof. Paper 516-C, 21 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. [1972].
-  Lansford, Henry, 1972, Boatman in the desert, a passenger-carrying
-          sternwheeler in canyon country: “Empire” [magazine of the
-          Denver Post], Nov. 5, p. 18, 19.
-  La Rue, E. C., 1916, Colorado River and its utilization: U.S. Geol.
-          Survey Water-Supply Paper 395, 231 p.
-  —— 1925, Water power and flood control of Colorado River below Green
-          River, Utah, with a foreword by Hubert Work, Secretary of the
-          Interior, p. 1-100. [Appendix A, A report on water supply, by
-          E. C. La Rue and G. F. Holbrook, p. 101-123; and Appendix B, A
-          geologic report on the inner gorge of the Grand Canyon of
-          Colorado River, by R. C. Moore, p. 125-171]: U.S. Geol. Survey
-          Water-Supply Paper 556, 176 p.
-  Lohman, S. W., 1965, 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.
-  McKnight, E. T., 1940, Geology of area between Green and Colorado
-          Rivers, Grand and San Juan Counties, Utah: U.S. Geol. Survey
-          Bull. 908, 147 p.
-  Ouellette, C. M., 1958, Over the top of Landscape Arch: Desert Mag.,
-          p. 13-16, March.
-  Pierson, Lloyd, 1960, Arches National Monument, _in_ Geology of the
-          Paradox basin fold and fault belt: Durango, Colo., Four
-          Corners Geol. Soc. Guidebook, 3d Ann. Field Conf., p. 17-21.
-  Schaafsma, Polly, 1971, Rock art of Utah: Cambridge, Mass., Harvard
-          Univ., Papers of the Peabody Museum of Archaeology and
-          Ethnology, v. 65, 169 p.
-  Stacy, J. R., 1962, Shortcut method for the preparation of
-          shaded-relief illustrations, _in_ Short papers in geology,
-          hydrology, and topography 1962: U.S. Geol. Survey Prof. Paper
-          450-D, p. D164-D165.
-  Stokes, W. L., 1952, Uranium-vanadium deposits of the Thompsons area,
-          Grand County, Utah, with emphasis on the origin of carnotite
-          ores: Utah Geol. and Mineralogical Survey Bull. 46, 51 p.,
-          December.
-  —— 1970, Canyonlands—Geology: Naturalist, v. 21, Summer, Special Issue
-          no. 2, p. 3-9.
-  Walters, H. H., 1956, Pacific Northwest Pipeline—The scenic inch, _in_
-          Geology and economic deposits of east-central Utah: Salt Lake
-          City, Intermountain Assoc. of Petroleum Geologists, p.
-          169-170.
-  Williams, P. L., 1964, Geology, structure, and uranium deposits of the
-          Moab quadrangle, Colorado and Utah: U.S. Geol. Survey Misc.
-          Geol. Inv. Map I-360.
-  Wilson, B. E., 1956, Arches National Monument, _in_ Geology and
-          economic deposits of east-central Utah: Salt Lake City,
-          Intermountain Assoc. of Petroleum Geologists, 7th Ann. Field
-          Conf., p. 50-51.
-  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.
-
-
-    [Illustration: Petroglyph figure]
-
-
-
-
-Footnotes
-
-
-[1]Mrs. Tanner, of Phoenix, Ariz., is the author of an earlier history
-    of Moab (her hometown). She has completed a revision entitled, “The
-    Far Country—A Regional History of Moab and La Sal, Utah,” which will
-    be serialized in the Moab Times-Independent, after which it will be
-    published.
-
-[2]For the benefit of visitors from countries in which the metric system
-    is used, the following conversion factors may be helpful: 1 inch =
-    2.54 centimeters, 1 foot = 0.305 meter, 1 mile = 1.609 kilometers, 1
-    U.S. gallon = 0.00379 cubic meter.
-
-[3]Barrier Creek flows through Horseshoe Canyon in the detached unit of
-    Canyonlands National Park. The canyon walls are adorned by striking
-    pictographs (Lohman, 1974, fig. 2). “Barrier Canyon style” is named
-    after the pictographs found in Horseshoe Canyon.
-
-[4]Plastic-relief maps are no longer available from the U.S. Army Map
-    Service but may be obtained from the T. N. Hubbard Scientific Co.,
-    Box 105, Northbrook, Ill. 60062. A topographic map at a scale of
-    1:250,000 of the Moab quadrangle and similar maps at a scale of
-    1:62,500 for the Thompson, Cisco, Moab, and Castle Valley
-    quadrangles are available from the U.S. Geological Survey, Denver
-    Distribution Section, Federal Center, Denver, Colo. 80225, from the
-    Canyonlands Natural History Association at Moab, and from privately
-    owned shops where maps are sold. Most of the park is covered by the
-    Thompson and Moab quadrangles. The southern part of the park is
-    shown also on the Moab 4 NW, Moab 4 NE, and Mt. Waas 3 NW
-    quadrangles at a scale of 1:24,000. A special topographic map of
-    Arches National Park at a scale of 1:50,000 is in preparation by the
-    U.S. Geological Survey. These maps also may be obtained from the
-    above-listed sources.
-
-[5]This is numbered stop 1 in the booklet referred to earlier “The Guide
-    to an Auto Tour of Arches National Park,” and corresponds to the
-    numeral one on a small sign at the roadside parking place. Some of
-    the other numbers are given in the pages that follow.
-
-
-
-
-                                 Index
-
-
-            [Italic page numbers indicate major references]
-
-
-                                   A
-                                                                     Page
-  Abajo Mountains                                                     101
-      artifacts                                                         9
-  Abbey, Edward                                                         3
-  Aborigines, occupation of area                                        9
-  Acknowledgments                                                   _105_
-  Anasazi people, petroglyphs                                          10
-  Anasazi ruins                                                    9, 103
-  Ancestral Colorado River                                             33
-  Anomalies, gravity, Salt Valley                                      32
-  Anticlines, salt                                                     31
-  Arches, broken remains                                               44
-      examples                                                       _46_
-      former abutments                                                 68
-      horizontal                                                       44
-      how they are formed                                              42
-      natural, defined                                               _40_
-      number in the park                                         40, _41_
-      origin and development                                           37
-      pothole                                                          44
-      vertical                                                     42, 44
-  Artifacts, La Sal and Abajo Mountains                                 9
-  Aspinall, Wayne, Representative                                       8
-
-
-                                    B
-  “Baby Arch”                                                  46, 63, 83
-  Balanced Rock                                                69, 70, 74
-  Banta, Jerry                                                        105
-  Bar-DX Ranch                                                 12, 13, 14
-  “Barrier Canyon style”                                               10
-  Bedding, wavy, Dewey Bridge Member                                   46
-  Beeson, Stib                                                         13
-  Beginning of a monument                                             _1_
-  Bending of rocks                                                   _24_
-  Bennett, Wallace F., Senator                                          8
-  Beroni, Pete                                                     14, 15
-  Black Canyon of the Gunnison National Monument                      102
-  Book Cliffs                                                         100
-  Breaking of rocks                                                  _24_
-  Bridge, natural, defined                                           _40_
-  Broken Arch                                                      46, 79
-  Brown-Stanton expedition, exploration                                15
-  Bryce Canyon National Park                                          103
-  Budge, Chuck                                                        105
-
-
-                                    C
-  Cache Valley                                                 56, 73, 77
-  Cache Valley anticline                         25, 32, 34, 55, 100, 101
-  Cache Valley graben                                             34, 100
-  Campground                                                           86
-      water supply                                                     87
-  Cane Creek anticline                                                 24
-  Canyon de Chelly National Monument                                  102
-  _Canyon King_                                                         8
-  Canyon Lands Section, Colorado Plateau                            9, 22
-  Canyonlands National Park                                 3, 9, 15, 102
-  Canyonlands Natural History Association                               8
-  Capitol Reef National Park                                          103
-  Carithers, Joe                                                      105
-  Carmel Formation                                                    100
-  Cassidy, Butch                                                       12
-  Caves, Entrada Sandstone                                              9
-  Cedar Breaks National Monument                                      103
-  Cedar Mesa Sandstone Member, Cutler Formation                   22, 102
-  Chinle Formation                                      32, 100, 102, 103
-  “Cisco Cutoff”                                                       16
-  Civilian Conservation Corps                                           2
-  Cliff dwellers                                                        9
-  Climate, desert                                                  35, 51
-      wetter, different landscape produced                             37
-  Collapse, salt anticlines                                        33, 34
-  Color photographs, equipment used                                     8
-  Colorado National Monument                                          102
-  Colorado Plateau, geologic formations included                      101
-      rock formations                                            103, 104
-      subdivisions                                                     18
-      uranium-vanadium mining                                          14
-  Colorado Plateaus Province                                           18
-  Colorado River, course established                                  101
-      nighttime illuminated float trip                             16, 52
-  Colorado River canyon                                      35, 51, _52_
-  Cores, salt                                                         100
-  Corral mine                                                          15
-  Courthouse syncline                     25, 30, 31, 32, 52, 63, 68, 100
-  Courthouse Towers area                                         25, _63_
-      number of arches                                                 41
-  Courthouse Wash                                        2, 3, 18, 35, 63
-  Cove Arch                                                            70
-  Cove of Caves                                                        70
-  Crossbedding, Navajo Sandstone                               63, 66, 70
-  Cutler Formation                                                32, 102
-      Cedar Mesa Sandstone Member                                      22
-      White Rim Sandstone Member                                       22
-
-
-                                    D
-  Dark Angel                                                           92
-  De Chelly Sandstone Member, Cutler Formation                        102
-  Dead Horse Point                                                     33
-  Dedication of the park                                                8
-  Delicate Arch                                        16, 25, 74, 75, 77
-  Delicate Arch area, number of arches                                 41
-  Density, average, Paradox Member                                     32
-  Deposition of rock materials, environments                         _20_
-  Desert varnish                                                       10
-  Development of the arches                                          _37_
-  Devils Garden                                    2, 5, 25, 79, _83_, 86
-      fins                                                             42
-      number of arches                                                 41
-      trail                                                        88, 92
-  Dewey Bridge                                                         52
-  Dewey Bridge Member                                              46, 63
-      Entrada Sandstone, composition                                   41
-          “hoodoos and goblins”                                        66
-          park road cutting                                            57
-          The Windows section                                          71
-          vertical arches                                              44
-  “Dewey Road”                                                         16
-  Diapir                                                               83
-  Differential erosion                                                 42
-  Dinosaur National Monument                                     101, 102
-  Dissimilarity of Arches vs. Canyonlands                          23, 24
-  Double Arch                                                   2, 46, 72
-  Double O Arch                                                90, 92, 98
-  Drainage, Arches National Park                                       18
-  Dry Mesa                                                          5, 56
-
-
-                                    E
-  Eagle Park                                                       25, 98
-      number of arches                                                 41
-  Early dwellers                                                      _9_
-  Earthquake, rock offset along bedding plane                          63
-  Egyptian queen, arch resembling                                      63
-  Eisenhower, Dwight D., Mission 66                                     4
-  Elephant Butte                                                       72
-  Elephant Butte folds                                                 68
-  Elizondo, Emmett                                                     13
-  Entrada Sandstone                                      23, 74, 102, 103
-      arches, modes of origin                                          42
-      caves                                                             9
-      cut by normal fault                                              57
-      Moab Member                                                      24
-      no water found                                                   87
-  Environments of deposition                                         _20_
-  Erosion                                                              99
-      Colorado Plateau                                               _33_
-  Evaporation basins                                                   99
-  Evaporites                                                           30
-  Eye of The Whale                                                     69
-
-
-                                    F
-  Facies changes                                                       22
-  “Father of the monument,” J. W. Williams                           1, 4
-  Faults, Cache Valley anticline                                       34
-      Salt Valley anticline                                            34
-  Fiery Furnace                                      25, 42, 73, _79_, 83
-      number of arches                                                 41
-  Fins                                                             63, 79
-  Float trip, nighttime illuminated, down Colorado River               52
-  Folds                                                     _24_, 30, 100
-  Four-wheel-drive vehicles                                            69
-  Fractures                                                          _24_
-  Fremont people, occupation of area                                    9
-      pictographs                                                      10
-  Frost, prying action                                                 42
-
-
-                                    G
-  Garden of Eden                                               50, 69, 70
-  Gas exploration, deep tests                                      15, 99
-  Geographic setting                                                 _18_
-  Geologic age of rocks in park                                      _98_
-  Geologic events forming the Colorado Plateau                       _98_
-  Geologic history, summary                                          _98_
-  Geologic Time Spiral                                           101, 103
-  Geology, at the park entrance                                        57
-  Glen Canyon Group                                          52, 102, 103
-  Glen Canyon National Recreation Area                           101, 103
-  Goblin Valley State Park                                        66, 103
-  Gould, Lawrence M.                                                    1
-  Goulding, Harry, first person to drive into The Windows section   2, 69
-  Grabens                                                              34
-  Grand Canyon National Park and National Monument                    102
-  Gravity anomalies, Salt Valley                                       32
-  Green River                                                         103
-  Ground water                                                         41
-  “Guide to an Auto Tour of Arches National Park,” (The)    5, 50, 51, 72
-  Gulf of California                                                   33
-
-
-                                    H
-  Hastier, (Mrs.) Hazel Wolfe                                          13
-  Headquarters area                                                  _57_
-  Henry Mountains                                                     101
-  Herdina Park                                                     25, 69
-      number of arches                                                 41
-  Hermosa Formation, Paradox Member                    23, 25, 29, 30, 32
-  History, early                                                      _9_
-      geologic, summary                                              _98_
-  “Hoodoos and goblins”                                           66, 103
-  Hoover, Herbert, proclamation                                         1
-  Horizontal arches                                                    44
-  Horseshoe Canyon, pictographs                                        10
-  Horseshoe Canyon Detached Unit of Canyonlands                        23
-  Humid regions, subdued rounded landforms                             37
-
-
-                                    I
-  Igneous rocks                                                    22, 99
-  “Indian-Head Arch”                                                   98
-  Iron in the rocks                                                    23
-  Island in the Sky                                                   102
-
-
-                                    J
-  Jeep trail                                                       69, 70
-  Johnson, Lyndon B., proclamation                                      2
-  Joints                                                    _24_, 34, 100
-
-
-                                    K
-  Kayenta Formation                                      35, 52, 102, 103
-  Kerr, Bob                                                           105
-  Klondike Bluffs                                        25, 69, _82_, 83
-      number of arches                                                 41
-
-
-                                    L
-  La Sal Mountains                                        22, 63, 77, 101
-      artifacts                                                         9
-  Lake Mead                                                            33
-  Lake Powell                                                          33
-  Land forms, formation in the park                                    33
-  Landscape Arch                                               16, 77, 88
-      second known ascent                                              90
-  Larson, Tommy                                                        13
-  Lloyd, Sherman P., Representative                                     8
-  Lohman, (Mrs.) Ruth                                                 105
-
-
-                                    M
-  Mahan, Russel L.                                                      2
-  Mancos Shale                                                    32, 100
-  Maxwell, Ross A., investigation of caves                          9, 10
-  May, David                                                      40, 105
-  Melich, Mitchell, Solicitor General                                   8
-  Mesaverde Group                                                 32, 103
-  Mesaverde National Park                                             103
-  Metamorphic rocks                                                22, 99
-  Metric unit conversion factors                                      _2_
-  Mikesell, Carl                                                      105
-  Miller, Joe                                                         105
-  Mission 66, presidential and congressional support                    4
-  Mississippi River sternwheeler replica                                8
-  Moab, uranium-vanadium mill                                          14
-  Moab bridge                                                          52
-  Moab Canyon                                                      15, 18
-  Moab fault                                                       26, 57
-  Moab Lions Club                                                    1, 8
-  “Moab Mail Road”                                                     16
-  Moab Member, Entrada Sandstone                                   24, 35
-      Entrada Sandstone, Broken Arch                                   46
-      composition                                                      41
-  “Moab panel”                                                         10
-  Moab-Spanish Valley anticline                                        26
-  Moab Valley                                                          57
-  Moab Valley-Seven Mile anticline                               100, 101
-  Moenkopi Formation                                         32, 102, 103
-  Monoliths                                                            63
-  Monument, beginning                                                 _1_
-  Monument Valley                                                101, 102
-  Morrison Formation                                              32, 101
-  Morton, Rogers C. B., Secretary of the Interior                       8
-  Moss, Frank E., Senator                                               8
-  Moss Back Member, Chinle Formation                                   15
-
-
-                                    N
-  National Park Service                                 8, 12, 40, 75, 90
-  Natural Bridges National Monument                        3, 37, 40, 102
-  Navajo Arch                                                          90
-  Navajo Sandstone                                        24, 35, 52, 103
-      canyon floor                                                     63
-      crossbedding                                             63, 66, 70
-      park road cutting                                                57
-      water supply                                                 57, 87
-  Navajo Tribe                                                        102
-  Needles section, The, Canyonlands National Park                 16, 102
-  Newell, (Mrs.) Maxine                                           12, 105
-  Nixon, Richard M., Congressional Bill                                 5
-  North Window                                                 40, 68, 71
-
-
-                                    O
-  Oil exploration                                                      15
-      Cane Creek anticline                                             24
-      deep tests                                                       99
-  Origin of the arches                                               _37_
-
-
-                                    P
-  Pacific Northwest Pipeline                                           15
-  Painted Desert                                                      102
-  Panorama Point                                                       73
-  Parade of Elephants                                                  72
-  Paradox basin                                                        23
-  Paradox Member, Hermosa Formation                23, 25, 29, 30, 82, 99
-      Hermosa Formation, average density                               32
-          upward intrusion                                             34
-  Park, a trip through                                               _52_
-      dedication                                                        8
-      how to see                                                     _50_
-      improvements                                                      4
-  Park Avenue, trail                                                   63
-  Park Service. _See_ National Park Service.
-  Partition Arch                                                       90
-  Petrified dunes                                                  63, 66
-  Petrified Forest National Park                                      102
-  Petroglyphs, Ute                                                 10, 75
-  Pictographs, Fremont people                                          10
-  Pine Tree Arch                                                       90
-  Piñon pines                                                          86
-  Pipeline scars, Pacific Northwest Pipeline                           15
-  Plateau, uplift and erosion                                        _33_
-  Potash occurrence                                                    15
-  Pothole Arch                                                     50, 73
-  Pothole arches                                                       44
-  Powell, John Wesley, Canyonlands National Park                       15
-  Professor Valley                                                     56
-
-
-                                    R
-  Rainbow Bridge National Monument                                    103
-  Rainwater                                                        41, 42
-  Rampton, Calvin L., Utah Governor                                     8
-  Reading, additional                                               _104_
-  References, selected                                              _105_
-  Relief map, shaded, Arches National Park, described              18, 19
-  Ribbon Arch                                                          72
-  Richardson Amphitheater                                              56
-  Richardson, Professor                                                56
-  Rico Formation                                                       23
-  Rison, (Mrs.) Esther Stanley                                         13
-  Rock formations, sculptured by erosion                               35
-  Rock openings, natural, types                                        37
-  Rock types in the park                                               35
-  Roosevelt, Franklin D., proclamation                                  2
-  Rumel, Hal, photographer                                             77
-  “Run, Cougar, Run”                                           16, 56, 75
-
-
-                                    S
-  Sagers Wash syncline                                                 86
-  Salt, occurrence                                                     15
-      properties critical to formation of salt anticlines              30
-  Salt anticlines                                             30, 31, 100
-      collapse                                                     33, 34
-  Salt-bearing rock                                                    83
-  Salt rolls                                                           31
-  Salt Valley                                 2, 68, 73, 77, _82_, 83, 92
-      gravity anomalies                                                32
-  Salt Valley anticline                      25, 30, 31, 32, 73, 100, 101
-      collapse                                                         34
-      fins                                                             42
-  Salt Valley Wash                                          3, 74, 82, 83
-  Salt Wash                                                        35, 55
-      Anasazi ruins                                                     9
-      drainage                                                         18
-      grabens                                                          34
-      sandstone caves near                                             10
-  Salt Wash Sandstone Member, Morrison Formation                       14
-  San Juan Basin, natural gas                                          15
-  San Rafael Swell                                               101, 103
-  Sand Dune Arch                                                       79
-  Sandstone fins                                                   41, 42
-  Schaafsma, Polly, quoted                                         10, 12
-  Scenic drive, Moab to Cisco                                          16
-  “Scenic Inch,” Pacific Northwest Pipeline                            15
-  Sedimentary rocks                                                    20
-      modes of deposition                                              99
-  Seven Mile-Moab Valley anticline                             26, 32, 57
-  Sevenmile Canyon                                                     15
-  Sheep Rock                                                           63
-  Skyline Arch                                                         83
-  Slick Rock Member, Entrada Sandstone                                 34
-      Entrada Sandstone, composition                                   41
-          high fins and pinnacles                              63, 79, 86
-          hiking trail between fins                                    90
-          park road cutting                                            57
-          salmon                                                       77
-          The Windows section                                          71
-          Tunnel Arch                                                  46
-          vertical arches                                          42, 44
-  Slumping of sediments, irregular                                     50
-  Snow                                                             41, 51
-  Sonic booms, dangers posed to arches                             16, 17
-  South Window                                                 40, 68, 71
-  Spanish explorers                                                    12
-      introduction of horses to this country                           10
-  Squaw Flat Campground                                                16
-  Stanley, Esther                                                      13
-      (Mrs.) Flora                                                     13
-      Volna                                                            13
-  Stevens, Dale J.                                     40, 41, 63, 90, 98
-  Strata, lateral changes across the park                              22
-  Sundance Kid                                                         12
-  Sunset Crater National Monument                                     103
-  Supersonic flights banned, Moab-Times Independent                    17
-  Suspension bridge, Colorado River                                    16
-
-
-                                    T
-  Tanner, (Mrs.) Faun McConkie                                          1
-  Taylor, L. L. (Bish)                                                  1
-  Temperatures                                                         51
-  “The Guide to an Auto Tour of Arches National Park”       5, 50, 51, 72
-  The Needles section, Canyonlands National Park                  16, 102
-  The Windows section                    25, 41, 46, 51, 66, _68_, 69, 70
-  Three Gossips                                                        63
-  Three Penguins                                                       57
-  Tower Arch                                                           83
-  Tunnel Arch                                                  40, 46, 90
-  Turnbow, Mary                                                         1
-  Turnbow cabin                                                        13
-  Turret Arch                                                      68, 71
-
-
-                                    U
-  Uncompahgre Highland                                        23, 99, 100
-  Uncompahgre Plateau                                              23, 99
-  Uplift, Colorado Plateau                                           _33_
-  Upper Devils Garden                                                  98
-      number of arches                                                 41
-  Uranium mines                                                        14
-  Ute petroglyphs                                                  10, 75
-
-
-                                    V
-  Vanadium mines                                                       14
-  Vegetation                                                           37
-  Vertical arches                                                  42, 44
-  Visitor Center                                           50, 51, 57, 86
-  Volz, J. Leonard                                                      8
-
-
-                                    W
-  Walker, Lester                                                       13
-  Wall Arch                                                            90
-  Walt Disney crew, “Run, Cougar, Run”                                 75
-  Wasatch Formation                                                    32
-  Water supply, Navajo Sandstone                                       57
-      to the campground                                                87
-  White Rim Sandstone Member, Cutler Formation                         22
-  Wild Bunch, The                                                      12
-  Williams, J. W.                                                    1, 4
-  Wilson, Bates                                                 1, 3, 105
-  Wilson, (Mrs.) Bates                                                  3
-  Windows, distinguished from arches                                 _40_
-  Windows section, The                       25, 46, 51, 66, _68_, 69, 70
-      number of arches                                                 41
-  Wingate Sandstone                                      35, 87, 102, 103
-  Wirth, Conrad L.                                                      4
-  Wolfe cabin                                            1, 3, 12, 13, 14
-  Wolfe, Fred                                                      12, 13
-  Wolfe, John Wesley                                               12, 13
-  Wolfe’s Bar-DX Ranch                                  9, 10, 14, 74, 75
-  Wupatki National Monument                                           102
-
-
-                                    Y
-  Yellow Cat area (Thompson’s area)                                    14
-  Yellow Cat Flat                                                      86
-  Yellow Cat mining district                                           83
-
-
-                                    Z
-  Zion National Park                                                  103
-
-                          ★U.S. GOVERNMENT PRINTING OFFICE: 1975—679-138
-
-    [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.
-
-—In the text versions only, text in italics is delimited by
-  _underscores_.
-
-—The HTML version contains relative hyperlinks to a companion volume on
-  Canyonlands National Park, Gutenberg eBook #51048.
-
-—A third book in the series, on Colorado National Monument, was revised
-  after this book was printed.
-
-
-
-
-
-
-
-End of the Project Gutenberg EBook of The Geologic Story of Arches National
-Park, by S. W. Lohman
-
-*** END OF THIS PROJECT GUTENBERG EBOOK GEOLOGIC STORY--ARCHES NATIONAL PARK ***
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-The Project Gutenberg EBook of The Geologic Story of Arches National Park, by 
-S. W. Lohman
-
-This eBook is for the use of anyone anywhere in the United States and most
-other parts of the world at no cost and with almost no restrictions
-whatsoever.  You may copy it, give it away or re-use it under the terms of
-the Project Gutenberg License included with this eBook or online at
-www.gutenberg.org.  If you are not located in the United States, you'll have
-to check the laws of the country where you are located before using this ebook.
-
-Title: The Geologic Story of Arches National Park
-       Geological Survey Bulletin 1393
-
-Author: S. W. Lohman
-
-Illustrator: John R. Stacy
-
-Release Date: February 3, 2016 [EBook #51116]
-
-Language: English
-
-Character set encoding: ISO-8859-1
-
-*** START OF THIS PROJECT GUTENBERG EBOOK GEOLOGIC STORY--ARCHES NATIONAL PARK ***
-
-
-
-
-Produced by Stephen Hutcheson, Dave Morgan and the Online
-Distributed Proofreading Team at http://www.pgdp.net
-
-
-
-
-
-
-    [Illustration: Geology of Arches National Park]
-
-    [Illustration: BALANCED ROCK, guarding The Windows section of Arches
-    National Park. Rock is Slick Rock Member of Entrada Sandstone
-    resting upon crinkly bedded Dewey Bridge Member of the Entrada.
-    White rock in foreground is Navajo Sandstone. La Sal Mountains on
-    right skyline. (Frontispiece)]
-
-    [Illustration: Graphic Title Page]
-
-
-
-
-                        _The Geologic Story of_
-                                 Arches
-                             NATIONAL PARK
-
-
-                            By S. W. Lohman
-                              Graphics by
-                             John R. Stacy
-
-                    GEOLOGICAL SURVEY BULLETIN 1393
-
-
-                UNITED STATES DEPARTMENT OF THE INTERIOR
-                    ROGERS C. B. MORTON, _Secretary_
-
-                           GEOLOGICAL SURVEY
-                       V. E. McKelvey, _Director_
-
-    [Illustration: Department of the Interior � March 3, 1949]
-
-                 U.S. GOVERNMENT PRINTING OFFICE: 1975
-
-
-  Library of Congress Cataloging in Publication Data
-  Lohman, Stanley William, 1907-
-  The geologic story of Arches National Park.
-  (Geological Survey Bulletin 1393)
-  Bibliography: p.
-  Includes index.
-  Supt. of Docs. no.: I 19.3:1393
-  1. Geology--Utah--Arches National Park--Guide-books.
-  2. Arches National Park, Utah--Guide-books.
-  I. Title. II. Series: United States Geological Survey
-  Bulletin 1393.
-  QE75.B9 No. 1393 [QE170.A7] 557.3'08s [557.92'58]
-  74-23324
-
-
- For sale by the Superintendent of Documents, U. S. Government Printing
-                                 Office
-                        Washington, D. C. 20402
-                      Stock Number 024-001-02598-1
-
-
-
-
-                                Contents
-
-
-                                                                     Page
-  Beginning of a monument                                               1
-  Graduation to a park                                                  5
-  Early history                                                         9
-      Prehistoric people                                                9
-      Late arrivals                                                    12
-  Geographic setting                                                   18
-  Deposition of the rock materials                                     20
-  Bending and breaking of the rocks                                    24
-  Uplift and erosion of the Plateau                                    33
-  Origin and development of the arches                                 37
-      Examples of arches                                               46
-  How to see the park                                                  50
-  A trip through the park                                              52
-      Colorado River canyon                                            52
-      Headquarters area                                                57
-      Courthouse Towers area                                           63
-      The Windows section                                              68
-      Delicate Arch area                                               74
-      Fiery Furnace                                                    79
-      Salt Valley and Klondike Bluffs                                  82
-      Devils Garden                                                    83
-  Summary of geologic history                                          98
-  Additional reading                                                  104
-  Acknowledgments                                                     105
-  Selected references                                                 105
-  Index                                                               109
-
-
-
-
-                                Figures
-
-
-                                                                     Page
-  Frontispiece. Balanced Rock.
-  1. Arches National Park                                               6
-  2. Rock art in Arches National Park                                  11
-  3. Wolfe's Bar-DX Ranch                                              14
-  4. Rock column of Arches National Park                               21
-  5. Common types of rock folds                                        25
-  6. Common types of rock faults                                       26
-  7. Paradox basin                                                     27
-  8. Geologic section across northwest end of Arches National Park     28
-  9. Index map of northwestern part of Arches National Park            28
-  10. Gravity anomalies over Salt Valley                               31
-  11. Tilted block of rocks in Cache Valley graben                     34
-  12. Jointed northeast flank of Salt Valley anticline                 36
-  13. Index map                                                        38
-  14. Tunnel Arch                                                      43
-  15. "Baby Arch"                                                      44
-  16. Broken Arch                                                      45
-  17. Double Arch                                                      47
-  18. Pothole Arch                                                     48
-  19. Glen Canyon Group                                                53
-  20. Navajo Sandstone cliffs                                          54
-  21. Mouth of Salt Wash                                               55
-  22. Southeast end of faulted Cache Valley anticline                  56
-  23. Faulted Seven Mile-Moab Valley anticline                         58
-  24. Three Penguins                                                   59
-  25. Moab Valley                                                      60
-  26. Faulted wall of Entrada Sandstone                                61
-  27. Park Avenue                                                      62
-  28. Balanced rocks on south wall of Park Avenue                      64
-  29. Courthouse Towers                                                65
-  30. The Three Gossips                                                66
-  31. Sheep Rock                                                       66
-  32. Petrified sand dunes                                             67
-  33. "Hoodoos and goblins"                                            68
-  34. Eye of The Whale                                                 69
-  35. Intricate crossbeds in Navajo Sandstone                          70
-  36. Cove Arch and Cove of Caves                                      71
-  37. North Window                                                     72
-  38. Looking southwestward through North Window                       73
-  39. South Window                                                     74
-  40. Turret Arch                                                      75
-  41. Parade of Elephants                                              76
-  42. Suspension foot bridge across Salt Wash                          78
-  43. Delicate Arch                                                    78
-  44. Fiery Furnace                                                    80
-  45. Trail to Sand Dune Arch                                          81
-  46. Sand Dune Arch                                                   82
-  47. Tower Arch                                                       84
-  48. Skyline Arch                                                     85
-  49. Campground in Devils Garden                                      86
-  50. View north from campground                                       87
-  51. Southeastern part of Devils Garden trail                         88
-  52. Pine Tree Arch                                                   89
-  53. Landscape Arch                                                   91
-  54. Navajo Arch                                                      92
-  55. Partition Arch                                                   93
-  56. Double O Arch                                                    93
-  57. Dark Angel                                                       94
-  58. "Indian-Head Arch"                                               95
-  59. Geologic time spiral                                             96
-
-    [Illustration: Petroglyph figure]
-
-
-
-
-Beginning of a Monument
-
-
-According to former Superintendent Bates Wilson (1956), Prof. Lawrence
-M. Gould, of the University of Michigan, was the first to recognize the
-geologic and scenic values of the Arches area in eastern Utah and to
-urge its creation as a national monument. Mrs. Faun McConkie Tanner[1]
-told me that Professor Gould, who had done a thesis problem in the
-nearby La Sal Mountains, was first taken through the area by Marv
-Turnbow, third owner of Wolfe cabin. (See p. 12.) When Professor Gould
-went into ecstasy over the beautiful scenery, Turnbow replied, "I didn't
-know there was anything unusual about it."
-
-Dr. J. W. Williams, generally regarded as father of the monument, and L.
-L. (Bish) Taylor, of the Moab Times-Independent, were the local leaders
-in following up on Gould's suggestion and, with the help of the Moab
-Lions Club, their efforts finally succeeded on April 12, 1929, when
-President Herbert Hoover proclaimed Arches National Monument, then
-comprising only 7 square miles.[2] It was enlarged to about 53 square
-miles by President Franklin D. Roosevelt's Proclamation of November 25,
-1938, and remained at nearly that size, with some boundary adjustments
-on July 22, 1960, until it was enlarged to about 130 square miles by
-President Lyndon B. Johnson's Proclamation of January 20, 1969.
-
-According to Breed (1947), Harry Goulding, of Monument Valley, in a
-specially equipped car, traversed the rugged sand and rocks of the
-Arches region in the fall of 1936 and, thus, became the first person to
-drive a car into The Windows section of Arches National Monument. Soon
-after, a bulldozer followed Harry's tracks and made a passable trail.
-
-When my family and I visited the monument in 1946, the entrance was
-about 12 miles northwest of Moab on U.S. Highway 163 (then U.S. 160),
-where Goulding's old tire tracks led eastward past a small sign reading
-"Arches National Monument 8 miles." This primitive road crossed the
-sandy, normally dry Courthouse Wash and ended in what is now called The
-Windows section. At that time there was no water or ranger station, nor
-were there any picnic tables or other improvements within the monument
-proper, and the custodian was housed in an old barracks of the Civilian
-Conservation Corps near what is now the entrance, 5 miles northwest of
-Moab.
-
-Former Custodian Russell L. Mahan reported (oral commun., May 1973) that
-soon after our initial visit in 1946 a 500-gallon tank was installed
-near Double Arch in The Windows section and connected to a drinking
-fountain and that two picnic tables and a pit toilet were added. At that
-time the only access to Salt Valley and what is now called Devils Garden
-was a primitive dirt road which, according to Breed (1947, p. 175), left
-old U.S. Highway 160 (now U.S. 163) 24 miles northwest of Moab, went 22
-miles east, then followed Salt Valley Wash down to Wolfe cabin (fig. 1).
-
-According to Abbey (1971), who served as a seasonal ranger beginning
-about 1958, a sign had by then been erected at the crossing of
-Courthouse Wash which read:
-
-                           WARNING: QUICKSAND
-                           DO NOT CROSS WASH
-                         WHEN WATER IS RUNNING
-
-The ranger station, his home for 6 months of the year, was what Abbey
-described as "a little tin housetrailer." Nearby was an information
-display under a "lean-to shelter." He had propane fuel for heat,
-cooking, and refrigeration, and a small gasoline-engine-driven generator
-for lights at night. His water came from the 500-gallon tank, which was
-filled at intervals from a tank truck. At that time there were three
-small dry campgrounds, each with tables, fireplaces, garbage cans, and
-pit toilets. By that time an extension of the dirt road led northward to
-Devils Garden, and some trails had been built and marked.
-
-Bates Wilson became Custodian of the monument in 1949 and later became
-Superintendent not only of Arches but also of the nearby new Canyonlands
-National Park (Lohman, 1974) and the more distant Natural Bridges
-National Monument. In the fall of 1969, Bates told me of some of his
-early experiences in the undeveloped monument, including the evening
-when 22 cars were marooned on the wrong (northeast) side of Courthouse
-Wash after a flash flood. Bates and his "lone" ranger brought ropes,
-coffee, and what food they could obtain in town after closing time,
-threw a line across the swollen stream, had a tourist pull a rope
-across, then took turns wading the stream with one hand on the rope and
-the other balancing supplies on his shoulder. After a fire had been
-built and hot coffee and food passed around, the spirits of the stranded
-group rose considerably, except for one irate woman from the East, who
-refused to budge from her car. Bates and his helper finally got the last
-car out about 1 a.m., after the flood had subsided, and Mrs. Wilson then
-supplied lodging and more food and coffee for those who needed it.
-
-During and for sometime after World War II and the Korean War, lack of
-maintenance funds and personnel had prevented improvement of the
-facilities in many of our national parks and monuments, particularly in
-undeveloped ones like Arches. The day was saved through the wisdom and
-foresight of former Park Service Director Conrad L. Wirth, who saw the
-need and desirability of putting the whole "want" list into one
-attractive, marketable package. In the words of Everhart (1972, p. 36):
-
-  Selection of a name is of course recognized as the most important
-  decision in any large-scale enterprise, and here Wirth struck pure
-  gold. In 1966 the Park Service would be celebrating its fiftieth
-  anniversary. What a God-given target to shoot for! Why not produce a
-  ten-year program, which would begin in 1956, aimed to bring every park
-  up to standard by 1966--and call it Mission 66?
-
-The ensuing well-documented and cost-estimated plan for Mission 66 was
-enthusiastically backed by President Dwight D. Eisenhower and approved
-and well supported by Congress to the tune of more than $1 billion
-during the 10-year period. For Arches, this included a new entrance,
-Park Headquarters, Visitor Center, a museum boasting a bust of founder
-Dr. Williams, and modern housing for park personnel, all 5 miles
-northwest of Moab. By 1958 (Pierson, 1960) a fine new paved road between
-Park Headquarters and Balanced Rock (frontispiece) was completed. These
-badly needed improvements were followed by the completion of the paved
-road all the way to Devils Garden, the building of the modern
-campground, picnic facilities, and amphitheater in the Devils Garden,
-and the construction of turnouts and marked trails.
-
-    [Illustration: Petroglyph figure]
-
-
-
-
-Graduation to a Park
-
-
-Arches graduated to a full-fledged national park when President Richard
-M. Nixon signed a Congressional Bill on November 16, 1971. The change in
-status was accompanied by boundary changes that reduced the area to
-about 114 square miles. The loss of most of Dry Mesa, just east of the
-present boundary (fig. 1), was offset in part by gains of new land
-northwest of Devils Garden. The present (1974) boundaries, roads,
-trails, and named features of the park are shown in figure 1.
-
-The park was virtually completed at graduation time, and so far this
-change in status has shown up mainly in new entrance signs, a new 1972
-brochure and map, and a very informative "Guide to an Auto Tour of
-Arches National Park," keyed to numbered signs at parking spaces. About
-all that remain to be added are new wayside exhibits, some boundary
-fences, and spur roads and trails.
-
-    [Illustration: ARCHES NATIONAL PARK, showing location in Utah,
-    boundaries, streams, highways and roads, trails, landforms,
-    principal named features, and the city of Moab. The reader is
-    referred to figure 7 and to road maps issued by the State or by oil
-    companies for the locations of other nearby towns and features.
-    Visitors also may obtain pamphlets, from the entrance station or
-    from the National Park Service office in Moab, which contain
-    up-to-date maps of the park and the latest available information on
-    roads, trails, campsites, and picnic sites. (Fig. 1)]
-
-Although Arches had officially become a park in November 1971, it was
-not formally dedicated until May 15, 1972. The ceremony began by having
-the Federal, State, and local dignitaries and other guests totaling 140
-persons board the _Canyon King_, a 93-foot replica of a Mississippi
-River sternwheeler (Lansford, 1972; Lohman, 1974, fig. 69), for its
-maiden voyage down the Colorado River. After about half an hour, the
-heavily laden boat became stuck on a sandbar, and after a 90-minute wait
-the passengers were rescued by jet boats. This delayed a luncheon at the
-Visitor Center put on by the Moab Lions Club. Following the luncheon,
-Park Superintendent Bates Wilson made a brief welcoming address, then
-introduced J. Leonard Volz, Director of the Midwest Region of the
-National Park Service, who served as master of ceremonies. Speakers
-included Utah Governor Calvin L. Rampton, Senator Frank E. Moss, a
-representative of Senator Wallace F. Bennett, Representatives Sherman P.
-Lloyd of Utah and Wayne Aspinall of Colorado, and Mitchell Melich,
-Solicitor General of the Department of Interior, representing Secretary
-Rogers C. B. Morton. After the speeches, a commemorative plaque, donated
-by the Canyonlands Natural History Association, was unveiled by Senator
-Moss and Mr. Melich.
-
-Most of the color photographs were taken by me on 4- x 5-inch film in a
-tripod-mounted press camera, using lenses of several focal lengths, but
-a few were taken on 35-mm film, using lenses of various focal lengths. I
-am grateful to several friends for the color photographs credited to
-them in the figure captions. The black and white photographs were kindly
-loaned from the Moab and Arches files of the National Park Service. The
-points from which most of the photographs were taken are shown in figure
-13.
-
-    [Illustration: Petroglyph figure]
-
-
-
-
-Early History
-
-
-                           Prehistoric People
-
-The Canyon lands in and south of Arches were inhabited by cliff dwellers
-centuries before the first visits of the Spaniards and fur trappers.
-Projectile points and other artifacts found in the nearby La Sal and
-Abajo Mountains indicate occupation by aborigines during the period from
-about 3000-2000 B.C. to about A.D. 1 (Hunt, Alice, 1956). The Fremont
-people occupied the area around A.D. 850 or 900, and the Pueblo or
-Anasazi people from about A.D. 1075 to their departure in the late 12th
-century (Jennings, 1970). Most of the evidence for these early
-occupations has been found in and south of Canyonlands National Park
-(Lohman, 1974), but some traces of these and possibly earlier cultures
-have been found also within Arches National Park.
-
-Ross A. Maxwell (National Park Service, written commun., 1941)
-investigated two caves in the Entrada Sandstone in the upper reaches of
-Salt Wash that contain Anasazi ruins. He mentioned that perhaps a dozen
-or more other caves should be checked for evidence of former occupation
-and, also, that he found several ancient campsites littered with flint
-chips and broken tools.
-
-One cave Maxwell explored some 5 miles north of Wolfe Ranch and north of
-the park is about 300 feet long and 100 to 150 feet deep. It contains
-the remains of one or more ruins of a structure he thought may have
-covered much of the floor. The remaining parts of walls now are only two
-to four tiers of stones in height, although originally they may have
-been more than one story high. Maxwell explored a second cave on the
-east side of Salt Wash, about 2 miles north of Wolfe Ranch, which
-contains 16 storage cists of adobe.
-
-The faces of many older sandstone cliffs or ledges are darkened by
-desert varnish--a natural pigment of iron and manganese oxides. The
-prehistoric inhabitants of the Plateau learned that effective and
-enduring designs, called petroglyphs, could be created simply by
-chiseling or pecking through the thin dark layer to reveal the buff or
-tan sandstone beneath. Most petroglyphs were created by the Anasazi, but
-those showing men mounted on horses were done by Ute tribesmen after the
-Spaniards brought in horses in the 1500's. The Fremont people and some
-earlier people painted figures on rock faces, called pictographs, and
-some of these had pecked outlines.
-
-The so-called "Moab panel" was described by Beckwith (1934, p. 177) as a
-petroglyph, but, as pointed out by Schaafsma (1971, p. 72, 73), it
-comprises figures having pecked outlines and painted bodies, which
-actually are combinations of petroglyphs and pictographs. This
-beautifully preserved group of paintings is shown in the upper
-photograph of figure 2. Mrs. Schaafsma goes on to say, concerning the
-"Moab panel":
-
-  The long tapered body, the antenna like headdresses, and the staring
-  eyes are characteristic features of Barrier Canyon style figures
-  elsewhere * * *. Of special interest here are the large shields held
-  by certain figures. A visit to this site indicated that the shields,
-  although apparently of some antiquity, have been superimposed over
-  some of the Barrier Canyon figures. Whether or not this was done by
-  the Barrier Canyon style artists themselves or later comers to the
-  site is impossible to tell.
-
-Although definite proof seems lacking, she suggested (written commun.,
-Nov. 3, 1973) that the "'Barrier Canyon style'[3] * * * is earlier than
-the work in the same region clearly attributable to the Fremont." Note
-the three bullet holes in and near the right-hand shield. A ledge above
-the panel that contained petroglyphs during her earlier visit had fallen
-to the base of the cliff by the time my wife and I inspected the panel
-in September 1973.
-
-    [Illustration: ROCK ART IN ARCHES NATIONAL PARK. A (above), "Moab
-    panel," on cliff of Wingate Sandstone above U.S. Highway 163 between
-    Courthouse Wash and Colorado River, believed to be the work of
-    "Barrier Canyon" style people. B (below), Petroglyphs on ledge of
-    sandstone in Morrison Formation on east side of Salt Wash just north
-    of Wolfe Ranch, believed to have been cut by Ute tribesmen. (Fig.
-    2)]
-
-    [Illustration: Fig. 2 B]
-
-Mrs. Schaafsma believes the petroglyphs in the lower photograph of
-figure 2 to be the work of Ute tribesmen, not only because of the
-horses, but also because of the stiff-legged appearance of the mountain
-sheep. Note the bullet hole above the panel.
-
-
-                             Late Arrivals
-
-Later arrivals in and near Arches National Park included first Spanish
-explorers, then trappers, cattlemen, cattle rustlers and horse thieves,
-followed in the present century by oil drillers, uranium hunters,
-jeepsters, and tourists. Butch Cassidy, the Sundance Kid, and other
-members of The Wild Bunch are known to have frequented parts of what is
-now Canyonlands National Park (Baker, Pearl, 1971), but it is not
-certain whether or not any of them traversed what is now Arches National
-Park.
-
-The first settler in what is now Arches National Park was a Civil War
-veteran named John Wesley Wolfe, who was discharged from the Union Army
-about 3 weeks before the Battle of Bull Run because he suffered from
-varicose veins. In 1888 his doctor told him he had to leave Ohio for a
-dryer climate or he would not live 6 months, so he took his son Fred
-west and settled on a tract of 150 acres along the west bank of Salt
-Wash, where his "Wolfe cabin" still stands (figs. 1, 3). From family
-letters and newspaper clippings compiled by Mrs. Maxine Newell and other
-members of the National Park Service (Maxine Newell, written commun.,
-1971), we learn what life in the area was like:
-
-  We have started a cattle spread on a desert homestead. We call it the
-  Bar-DX Ranch. Fred and I live in a little log house on the bank of a
-  creek that is sometimes dry, sometimes flooded from bank to bank with
-  roaring muddy water. We are surrounded with rocks--gigantic red rock
-  formations, massive arches and weird figures, the like of which youve
-  [sic] never seen. The desert is a hostile, demanding country, hot in
-  summer, cold in winter. The Bar-DX Ranch is a day's ride from the
-  nearest store, out of the range of schools.
-
-Although John Wolfe had promised his wife and his other children that he
-would return home the first fall that his cattle sales netted enough
-money, he and Fred stayed on and on, and his wife refused to go west and
-join her husband and son. Eighteen years later he sent money from his
-pension check to his daughter, Mrs. Flora Stanley, his son-in-law, Ed
-Stanley, and his two grandchildren, Esther and Ferol, to join him and
-Fred at the ranch. Their train was met at Thompson Springs (now
-Thompson), Utah (fig. 7), by John Wolfe for the 30-mile ride to the
-ranch by horse and wagon. Sight of the tiny log cabin with only a dirt
-floor brought tears to his daughter's eyes, but her spirits rose
-considerably after John Wolfe promised to build a new log cabin with a
-wooden floor. But the children were enchanted with this strange country,
-with the building of the new cabin, and, especially, with getting to go
-rabbit hunting with Grandpa Wolfe. The Stanleys stayed at the ranch
-until Esther was 10, then moved to Moab to await the arrival of their
-third child, Volna.
-
-In 1910 John Wolfe sold the Bar-DX Ranch, and the entire family moved to
-Kansas. John Wolfe later moved back to Ohio, and died at Etna, Licking
-County, on October 22, 1913, at the age of 84, 25 years after his doctor
-had warned him to move to a dryer climate or face an early death.
-
-Wolfe had sold his spread to Tommy Larson, who later sold it to J. Marv
-Turnbow and his partners, Lester Walker and Stib Beeson. The old log
-cabin gradually came to be known as the "Turnbow cabin," and this name
-appeared on early maps of the area by the U.S. Geological Survey and on
-early pamphlets by the National Park Service, partly because Marv
-Turnbow served as a camphand in 1927 assisting in the first detailed
-geologic mapping of the area (Dane, 1935, p. 4). In 1947 the ranch was
-sold to Emmett Elizondo, who later sold it to the Government for
-inclusion in what was then the monument.
-
-From information supplied by Wolfe's granddaughter, Mrs. Esther Stanley
-Rison, and his great-granddaughter, Mrs. Hazel Wolfe Hastler, who
-visited the cabin in July 1970, the original name Wolfe cabin, or Wolfe
-Ranch, has been restored, and appears on the newer maps and pamphlets.
-(See fig. 1.) What remains of Wolfe's Bar-DX Ranch is shown in figure 3.
-
-    [Illustration: WOLFE'S BAR-DX RANCH, on west bank of Salt Wash at
-    start of trail to Delicate Arch. Left to right: Corral, wagon, "new"
-    cabin, and root cellar. "Old" cabin, which formerly was to right of
-    photograph, was washed away by a flood in 1906. (Fig. 3)]
-
-Arches National Park is surrounded by active uranium and vanadium mines
-and by many test wells for oil, gas, and potash; it is underlain by
-extensive salt and potash deposits. Oil and gas are produced a few miles
-to the north and east, and potash is being produced about 12 miles to
-the south (Lohman, 1974).
-
-Uranium and vanadium have been mined on the Colorado Plateau since 1898
-(Dane, 1935, p. 176) and in the Yellow Cat area (also called Thompson's
-area), just north of the park (fig. 1), since about 1911 (Stokes, 1952,
-p. 7). The deposits in the Yellow Cat area occur in the Salt Wash
-Sandstone Member of the Morrison Formation (fig. 4). According to Pete
-Beroni (U.S. Atomic Energy Commission, oral commun., August 6, 1973),
-some ore is still being produced in the Yellow Cat area, and the
-production of vanadium ore will increase as soon as the uranium mill at
-Moab is converted to also handle vanadium ore. The Corral and so-called
-Shinarump mines along the southwest side of Moab Canyon just north of
-Sevenmile Canyon (fig. 1) are still actively producing uranium ore from
-the Moss Back Member of the Chinle Formation, according to Mr. Beroni.
-
-The occurrences of salt and potash in and near the park and the attempts
-to find oil and gas nearby are discussed in a recent report (Hite and
-Lohman, 1973), and the deposits beneath Moab, Salt, and Cache Valleys
-are discussed in later chapters.
-
-In 1955 and 1956 the Pacific Northwest Pipeline, known also as the
-"Scenic Inch," was constructed by the Pacific Northwest Pipeline Corp.
-to transmit natural gas from wells in the San Juan Basin of northwestern
-New Mexico for a total of 1,487 miles to the Pacific Northwest, with
-additional pickups from gas fields in northeastern Utah, northwestern
-Colorado, and southwestern Wyoming (Walters, 1956). This 26-inch
-pipeline follows the general route of U.S. Highway 163 from Cortez,
-Colo., past Moab to Sevenmile Canyon 10 miles northwest of Moab, where
-it turns abruptly to the northeast and crosses about the middle of
-Arches National Park. It crosses the park road and the flat area between
-the Fiery Furnace and the southeast end of Devils Garden, but the scars
-are so well healed that most visitors are unaware of its existence
-unless they happen to look southwestward across Salt Valley, where the
-filled excavation is still visible. The filled trench also appears in
-the lower middle of figure 23.
-
-Unlike Canyonlands National Park a few miles to the south, Arches was
-not on the route of the famous early-day river expeditions of John
-Wesley Powell or of most of those that followed; however, the
-southeastern boundary of the park is the Colorado River, formerly the
-Grand, which was traversed by the first leg of the ill-fated
-Brown-Stanton expedition (Dellenbaugh, 1902, p. 343-369; Lohman, 1974).
-
-The canyon of the Colorado River along the southeastern park boundary is
-deep and beautiful and is a favorite stretch of quiet water for boaters
-and floaters. Partly paved State Highway 128 on the east bank is a part
-of a most scenic drive from Moab to Cisco--a small railroad town about
-32 miles northeast of the eastern border of figure 1 (fig. 7). This road
-has been variously called the "Moab Mail Road," the "Cisco Cutoff," the
-"Dewey Road," or the "Dewey Bridge Road" after an old suspension bridge
-(fig. 7) across the Colorado River at the old townsite of Dewey about 12
-miles south of Cisco. During the summer this deep colorful canyon may be
-viewed at night by artificial illumination. Each evening one-half hour
-after sundown, an 80-passenger jet boat leaves a dock north of the
-highway bridge, carries passengers several miles upstream, then floats
-slowly downstream followed by a truck on the highway carrying 40,000
-watts of searchlights which play back and forth on the colorful red
-canyon walls, while the passengers listen to a taped discourse. The
-entire trip requires about 2 hours.
-
-The spectacular arches and red rocks of Arches and vicinity have been
-used to advantage in making color movies and color TV shows. Parts of
-the recent Walt Disney film "Run, Cougar, Run" were filmed beneath
-Delicate Arch (fig. 43), in Professor Valley of the Colorado River just
-east of the park (fig. 7), and in other sections of the canyon country.
-
-Ever since military jet aircraft broke the sound barrier, there has been
-a growing number of protests from concerned citizens, organizations, and
-National Park Service officials concerning the dangers sonic booms have
-posed to Indian ruins and delicate erosional forms in our national parks
-and monuments, such as natural bridges, arches and windows, balanced
-rocks, and natural spires or towers. Many instances of damaged ruins,
-roads, erosional forms, and broken windows were reported. My wife and I
-can vouch for the destructive power of such booms, for in October 1969,
-while we were having breakfast at Squaw Flat Campground in The Needles
-section of Canyonlands National Park, a particularly severe blast from a
-low-flying jet not only violently rocked our jack-supported trailer but
-broke the windshield of our car.
-
-At Arches National Park, particular fear was felt for Landscape Arch
-(fig. 53), thought to be the longest natural stone arch in the world,
-and many a special round trip from headquarters involving 47 road miles
-and 2 trail miles was made to check on the condition of this arch after
-especially loud sonic booms were heard. Finally, in April 1972,
-following a rash of newspaper and magazine articles that spread across
-the nation, the Secretary of the Air Force put a virtual stop to this
-danger by ruling that, except in an emergency (Moab Times-Independent,
-April 12, 1972):
-
-  Supersonic flights must not only avoid passing over national parks,
-  they also may not fly near them, according to the new regulation. For
-  each 1,000 feet of altitude, the pilot must allow one-half mile
-  between the flight path and the park boundary. The regulation also
-  prohibits supersonic flights below 30,000 feet (over land) so the high
-  speed planes must allow 15 miles between the nearest park boundary and
-  the flight path.
-
-Let us hope that with the aid of this long-needed regulation and
-cooperation from visitors, the arches will remain intact for many more
-generations to see.
-
-    [Illustration: Petroglyph figure]
-
-
-
-
-Geographic Setting
-
-
-Geologists have divided the United States into many provinces, each of
-which has distinctive geologic and topographic characteristics that set
-it apart from the others. One of the most intriguing and scenic of these
-is the Colorado Plateaus province, referred to in this report simply as
-the Colorado Plateau, or the Plateau (Hunt, C. B., 1956, fig. 1). This
-province, which covers some 150,000 square miles and is not all
-plateaus, as we shall see, 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. Arches National Park occupies part of the Canyon Lands
-Section, one of the six subdivisions of the Plateau. As the names imply,
-the Canyon Lands Section of the Plateau comprises a high plateau
-generally ranging in altitude from 5,000 to 7,000 feet, which has been
-intricately dissected by literally thousands of canyons.
-
-Arches National Park is drained entirely by the Colorado River, whose
-deep canyon borders the park on the southeast (fig. 1). Most of the park
-is drained by Salt Wash, which enters the Colorado River just southeast
-of The Windows section, but the southwestern part is drained by
-Courthouse Wash and Moab Canyon, whose flows join the Colorado just west
-of the bridge on which U.S. Highway 163 crosses the river.
-
-When viewed at a distance of 1 foot, the shaded relief map (fig. 1)
-shows the general shape of the land surface in and near Arches National
-Park to the same horizontal scale as it would appear to a person in a
-spacecraft flying at a height of 250,000 feet, or about 47.5 miles. This
-map was prepared from part of the reverse side of a plastic-relief
-map[4] at a scale of 1:250,000 by the U.S. Army Map Service of the Moab
-quadrangle, using a simple time- and money-saving method (Stacy, 1962).
-
-    [Illustration: Petroglyph figure]
-
-
-
-
-Deposition of The Rock Materials
-
-
-The vivid and varied colors of the bare rocks and the fantastic buttes,
-spires, columns, alcoves, caves, arches, and other erosional forms of
-Arches National Park result from a fortuitous combination of geologic
-and climatic circumstances and events unequalled in most other parts of
-the world.
-
-First among these events was the piling up, layer upon layer, of
-thousands of feet of sedimentary rocks under a wide variety of
-environments. Sedimentary rocks of the region are composed of clay,
-silt, sand, and gravel carried and deposited by moving water; silt and
-sand transported by wind; and some materials precipitated from water
-solutions, such as limestone (calcium carbonate), dolomite (calcium and
-magnesium carbonate), gypsum (calcium sulfate with some water),
-anhydrite (calcium sulfate alone), common salt (sodium chloride), potash
-minerals, such as potassium chloride, and a few other less common types.
-Some of the beds were laid down in shallow seas that once covered the
-area or in lagoons and estuaries near the sea. Other beds were deposited
-by streams in inland basins or plains, a few were deposited in lakes,
-and the constituents of deposits like the Navajo Sandstone, were carried
-in by the wind. The character and thickness of the exposed sedimentary
-rocks and the names and ages assigned to them by geologists are shown in
-the rock column (fig. 4) and in the cross section (fig. 8). The history
-of their deposition is summarized on pages 98-102. Figure 4 was compiled
-mainly from generalized sections given by A. A. Baker (1933), Dane
-(1935), McKnight (1940), and Wright, Shawe, and Lohman (1962), and, in
-part, from Hite and Lohman (1973).
-
-    [Illustration: ROCK COLUMN OF ARCHES NATIONAL PARK. Average
-    thickness of units 250-1,000 feet is exaggerated two times; those
-    less than 250 feet, four times. 1 foot = 0.305 meter. (Fig. 4)]
-
-
-  AGE (millions of yrs ago)
-    GEOLOGIC AGE
-      NAME OF ROCK UNIT
-            KIND OF ROCK AND HOW IT IS SCULPTURED BY EROSION
-              THICKNESS (feet)
-                NAMED FOR OCCURRENCE AT OR NEAR
-
-
-  100
-    Late Cretaceous
-      Mancos Shale
-            Lead-gray fossiliferous marine shale. Forms slopes.
-              ?
-                Mancos, Colo.
-      Dakota Sandstone
-            Conglomeratic sandstone, gray shale, carbonaceous shale, and
-                  coal. Forms ledge.
-              100
-                Dakota, Nebr.
-      Unconformity
-    Late Jurassic
-      Morrison Fm.
-              700
-                Morrison, Colo.
-        Brushy Basin Member
-            Variegated shale, some sandstone and conglomerate, petrified
-                  wood, chert, and dinosaur bones. May contain some beds
-                  of Burro Canyon (Early Cretaceous) age.
-        Salt Wash Member
-            Crossbedded white and gray conglomeratic sandstone beds and
-                  lenses, locally carnotite bearing, and red and gray
-                  sandy mudstone. Forms slopes.
-      Unconformity
-  160
-      San Rafael Group
-                (San Rafael Swell, Utah)
-        Summerville Fm.
-            Thin bedded red sandstone and shale. Some cherty limestone
-                  concretions. Forms slopes.
-              0-40
-                Summerville Point, Utah
-        Entrada Ss.
-                (Entrada Point, Utah)
-          Moab Member
-            White, crossbedded fine-grained sandstone. Caps Slick Rock
-                  Member north of Devils Garden and Fiery Furnace and on
-                  Klondike Bluffs.
-              0-100
-                Moab, Utah
-          Slick Rock Member
-            Salmon-colored to pink and white fine-grained generally
-                  crossbedded sandstone, containing some medium- to
-                  coarse-grained sand. Generally forms cliffs or narrow
-                  fins many of which contain arches or windows.
-              0-240
-                Slick Rock, Colo.
-          Dewey Bridge Member
-            Red muddy sandstone and sandy mudstone, with contorted
-                  bedding. Forms easily eroded bases to arches in
-                  Windows Section, hence aided in their development.
-              0-175
-                Dewey Bridge, Utah
-      Unconformity
-  190
-    Jurassic and Triassic(?);
-      Glen Canyon Group
-        Navajo Sandstone
-            Massive crossbedded buff, gray, and white fine-grained
-                  sandstone, and local beds of gray limestone. Forms
-                  cliffs along Colorado River, floors Windows Section.
-              0-350
-                Navajo Country, Four Corners (Glen Canyon, U.)
-    Late Triassic(?)
-        Kayenta Formation
-            Lavender, gray, and white lenses of sandstone, red sandy
-                  shale, and conglomerate. Contains some freshwater
-                  shells. Caps and protects cliffs of Wingate Sandstone.
-              0-250
-                Kayenta, Ariz.
-    Late Triassic
-        Wingate Sandstone
-            Massive, horizontally bedded and crossbedded reddish buff
-                  fine-grained sandstone. Forms vertical cliffs along
-                  Colorado River, Cache Valley, Salt Wash, and
-                  Courthouse Wash.
-              0-350
-                Fort Wingate, N. Mex.
-  200
-      Chinle Formation
-            Irregularly bedded buff to red sandstone, red mudstone,
-                  limestone, and conglomerate. Lenticular sandstone and
-                  conglomerate (Moss Back Member) locally at base.
-                  Freshwater shells, petrified wood, reptile bones.
-                  Forms slopes.
-              0-700
-                Chinle Valley, Ariz.
-                Moss Back Ridge, Utah  Unconformity
-    Middle(?) and Early Triassic
-      Moenkopi Formation
-            Thin-bedded brown shale, gray and brown sandstone, arkosic
-                  grit, and conglomerate. Crops out on southwest side of
-                  Moab Valley and in several places in Salt and Cache
-                  Valleys. Forms slopes.
-              0-1,300
-                Moenkopi Wash, Ariz.
-      Unconformity
-  250
-    Permian
-      Cutler Formation
-            Chocolate brown and red sandy shale, maroon and pinkish-gray
-                  arkose and conglomerate. Lower part probably
-                  equivalent in age to Rico Formation in areas to south
-                  and east. Crops out in Moab Canyon west of Moab fault.
-                  Forms slopes.
-              0-2,500
-                Cutler Creek, Colo.
-    Pennsylvanian
-      Hermosa Formation
-        Unnamed upper member
-            Gray marine fossiliferous sandy limestone, gray and
-                  greenish-gray sandstone and sandy shale, and red sandy
-                  shale. Exposed in ledges southwest of Moab fault in
-                  highway cut west of park entrance.
-              0-1,500
-                Hermosa Creek, Animas River Valley, Colo.
-  300
-        Paradox Member
-            Salt, gypsum, and anhydrite, with black and gray shale and
-                  limestone. Few exposures in Salt and Cache Valleys.
-                  Forms slopes.
-              0-11,000
-                Paradox Valley, Colo.
-      Unconformity
-    Pennsylvanian(?)
-      Unnamed conglomerate
-            Yellow sandstone with boulders of limestone and chert
-                  containing Mississippian fossils. Exposed at two
-                  places in Salt Valley.
-              ?
-
-
-Not exposed in the area but present far beneath the sedimentary cover
-and exposed in several places a few miles to the northeast are examples
-of the other two principal types of rocks--(1) igneous rocks, solidified
-from molten rock forced into or above preexisting rocks along cracks,
-joints, and faults, and (2) much older metamorphic rocks, formed from
-other preexisting rock types by great heat and pressure at extreme
-depths. Igneous rocks of Tertiary age (fig. 59) form the nearby La Sal
-Mountains. The particles comprising the sedimentary rocks in the area
-were derived by weathering and erosion of all three types of rocks in
-various source areas.
-
-Arches National Park and nearby Canyonlands National Park are both in
-the heart of the Canyon Lands Section of the Plateau; therefore, it is
-only reasonable to wonder why the differences in their general character
-seemingly outweigh their similarities. First, let us consider the
-similarities. Both parks are underlain by dominantly red sedimentary
-rocks, both parks feature unusual erosional forms of sandstone, and both
-contain beautiful natural arches, although the arches in Canyonlands are
-restricted almost entirely to the southeastern part of The Needles
-section and are in much older rocks than those in Arches.
-
-To be sure, differences in the rocks themselves play a part in the
-dissimilarity of the two parks, and these differences are of two types.
-First, there are lateral changes in the character of the strata, known
-to geologists as facies changes, brought about by differences in the
-environment, in the type of materials, and in the mode of deposition
-even within relatively short distances. Thus, during parts of the
-Permian Period while sand, later to be known as the Cedar Mesa and White
-Rim Sandstone Members of the Cutler Formation, was being deposited in
-the southern part of Canyonlands, red mud, silt, and sand of the Cutler
-were laid down farther north in Canyonlands (Lohman, 1974, fig. 9), and
-similar, though somewhat coarser, beds of the Cutler were laid down at
-Arches (fig. 4). Further comparisons of the rock columns in the two
-parks show that while limestones of the Rico Formation were being
-deposited in a shallow sea in the southern part of Canyonlands,
-additional red mud, silt, and sand of the Cutler were being laid down
-above sea level in areas to the northeast. The source of the coarser
-materials was the ancient Uncompahgre Highland, which stood above sea
-level from Late Pennsylvanian time to Late Triassic time (figs. 7, 59).
-Although wider and longer, it occupied about the same position as the
-present Uncompahgre Plateau between Grand Junction and Gateway, Colo.
-Streams eroded the hard igneous and metamorphic rocks from this ancient
-landmass and dumped the material into basins to the northeast and
-southwest. The basin to the southwest, now called the Paradox basin
-(after Paradox Valley, Colo.), at intervals contained shallow seas and
-lagoons, which I will discuss later.
-
-Comparison of the rock columns for the two parks also reveals other
-differences. Both parks contain exposures of rocks as old as the
-Pennsylvanian Paradox Member of the Hermosa Formation. However, only in
-the Horseshoe Canyon Detached Unit of Canyonlands are rocks as young as
-the Jurassic Entrada Sandstone, whereas all the spectacular natural
-arches that make Arches famous were formed in the Entrada Sandstone, and
-Arches also contains several younger formations of Jurassic and
-Cretaceous age (fig. 4).
-
-A commonly asked question is "Why are most of the rocks so red,
-particularly those in which the arches were formed?" This can be
-answered with one word--iron, the same pigment used in rouge and in
-paint for barns and boxcars. 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,
-generally only 1 to 3 percent, is enough to produce even the darkest
-shades of red. The white or nearly white Navajo Sandstone and the Moab
-Member of the Entrada Sandstone contain little or no iron.
-
-As pointed out by Stokes (1970, p. 3), microscopic examination of the
-colored grains of quartz or other minerals shows the pigment to be
-merely a thin coating on and between white or colorless particles. Sand
-or silt weathered from such rocks soon loses its color by the scouring
-action of wind or water, so that most of the sand dunes and sand bars
-are white or nearly so.
-
-
-
-
-                   Bending And Breaking of The Rocks
-
-
-Perhaps the greatest geologic contrast between these two closely
-adjacent parks lies in their different geologic structure--the kind and
-amount of bending and breaking of the once nearly flat lying strata.
-Consolidated rocks, particularly brittle types, are subject to two types
-of fracturing by Earth forces. Joints are fractures along which no
-movement has taken place. Faults are fractures along which there has
-been displacement of the two sides relative to one another (fig. 6). As
-noted in the report on Canyonlands National Park (Lohman, 1974), the
-strata there, particularly along the valley of the Green River, are
-virtually flat lying or have only very gentle dips. Along the Colorado
-River above the confluence with the Green, however, the slightly dipping
-strata are interrupted by several gentle anticlinal and synclinal folds
-(fig. 5) and by at least one fault (fig. 6). The largest of these
-folds--the Cane Creek anticline, which crosses the Colorado River north
-of Canyonlands--has yielded oil in the past and is now yielding potash
-by solution mining of salt beds in the Paradox Member of the Hermosa
-Formation.
-
-    [Illustration: COMMON TYPES OF ROCK FOLDS. Top, Anticline, or
-    upfold; closed anticlines are called domes. Bottom, Syncline, or
-    downfold; closed synclines are called basins. From Hansen (1969, p.
-    31, 108). (Fig. 5)]
-
-In strong contrast to Canyonlands, Arches National Park contains three
-northwesterly trending major folds and is bordered on the southwest by a
-fourth. The largest and most important are the collapsed Salt Valley and
-Cache Valley anticlines, which separate the two most scenic groups of
-arches and other erosional forms--Eagle Park, Devils Garden, Fiery
-Furnace, and Delicate Arch on the northeast, and Klondike Bluffs,
-Herdina Park, and The Windows section on the southwest. Farther
-southwest is the Courthouse syncline, containing the attractive group of
-erosional forms called Courthouse Towers (fig. 1). Finally, near the
-southwest edge of the park, is the Seven Mile-Moab Valley anticline
-(also known as the Moab-Spanish Valley anticline), whose southwest limb
-is cut off by the Moab fault (figs. 7, 23). The folds just named and the
-sharply contrasting geologic structures of the two parks are well shown
-on sheet 2 of the geologic map of the Moab quadrangle (Williams, 1964),
-and the geologic formations are shown in color on sheet 1.
-
-    [Illustration: COMMON TYPES OF FAULTS. Top, Normal, or gravity
-    fault, resulting from tension in and lengthening of the Earth's
-    crust. Bottom, reverse fault, resulting from compression in and
-    shortening of the Earth's crust. Low-angle reverse faults generally
-    are called overthrusts or overthrust faults. In both types, note
-    amount of displacement and repetition of strata. Displacements may
-    range from a few inches or feet to many thousands of feet. From
-    Hansen (1969, p. 116). (Fig. 6)]
-
-    [Illustration: PARADOX BASIN, in southeastern Utah and southwestern
-    Colorado, showing the extent of common salt and major potash
-    deposits in the Paradox Member of the Hermosa Formation, and the
-    salt anticlines. Adapted from Hite (1972, fig. 1B). (Fig. 7)]
-
-    [Illustration: GEOLOGIC SECTION ACROSS NORTHWEST END OF ARCHES
-    NATIONAL PARK, showing strata beneath Courthouse syncline and Salt
-    Valley anticline. For line of section, see figure 9. Caprock
-    consists of gypsum and shale, from which common salt has been
-    leached by ground water, covered by alluvium. Heavy slanted lines
-    near crest of anticline are faults. Adapted from Hite and Lohman
-    (1973, fig. 13). (Fig. 8)]
-
-    [Illustration: INDEX MAP OF NORTHWESTERN PART OF ARCHES NATIONAL
-    PARK, showing axes of Courthouse syncline and Salt Valley anticline,
-    line of section _A_-_A_' in figure 8 and line of section _B_-_B_' in
-    figure 10. Open circles along line of section are sites of test
-    wells for oil, gas, or potash. Adapted from Hite and Lohman (1973,
-    fig. 12). (Fig. 9)]
-
-Arches National Park and most of nearby Canyonlands National Park lie
-within what geologists have termed the "Paradox basin," which contains a
-remarkable assemblage of sediments called the Paradox Member of the
-Hermosa Formation. These deposits were laid down in shallow seas and
-lagoons during Middle Pennsylvanian time, roughly 300 million years ago
-(fig. 59). As indicated in figure 4, the Paradox Member contains, in
-addition to shale and limestone, minerals deposited by the evaporation
-and concentration of sea water--common salt, gypsum, anhydrite, and
-potash salts. For this reason such deposits are collectively called
-evaporites. Figure 7 also shows that the northeastern part of the
-Paradox basin, which is the deepest part, contains a series of partly
-alined anticlines which have cores of salt and, hence, are called salt
-anticlines. As might be expected, roughly alined synclines intervene
-between the anticlines, but are not shown because of space limitations.
-According to Cater (1970, p. 50): "The salt anticlines of Utah and
-Colorado are unique in North America both in structure and in mode of
-development." To this may be added that they also are relatively rare in
-the world.
-
-A section across the Salt Valley anticline and the Courthouse syncline
-in the northwestern part of the park is shown in figure 8, and the axes
-of these structures are shown in figure 9.
-
-Normally, a series of roughly parallel northwestward-trending folds
-would result from shortening of a segment of the Earth's crust by
-compressive forces from the northeast and the southwest, but such does
-not seem to be the origin of these folds. The folds occur in a
-relatively narrow belt along the northeastern part of the Paradox basin,
-the deepest part, which was broken by a series of northwesterly trending
-normal faults (fig. 6) that cut the deep-lying Precambrian and older
-Paleozoic rocks (fig. 8) prior to the deposition of the salt-bearing
-Paradox Member of the Hermosa Formation. Movement along these faults
-continued intermittently during and after deposition of the Paradox,
-however, and resulted in the formation of a series of northwesterly
-trending ridges and troughs. Following Paradox time, normal sediments
-derived from a rising landmass to the northeast began to fill the basin.
-These sediments accumulated most rapidly and to greater thicknesses in
-the fault-derived troughs. Salt differs from normal sediments in two
-properties critical to the development of salt anticlines: first, salt
-is considerably lighter (fig. 10), and, second, salt under pressure will
-flow slowly by plastic deformation, much like ice in a glacier flows
-slowly downstream. Thus, salt in the troughs underlying the thicker and
-heavier masses of sediments was squeezed into the adjoining ridges,
-causing them to rise. Once started, this process tended to be
-self-perpetuating, as the flow of salt from beneath the thick masses of
-sediments in the troughs made room for the accumulation of still greater
-thicknesses of normal sediments. Consequently, the troughs receiving
-most of the sediments began to form downfolds, or synclines, and the
-ridges receiving little or no normal sediments began to form huge salt
-rolls that later were to become the cores of the salt anticlines when
-finally the ridges too were buried by sediments. Thus, the cross section
-(fig. 8) shows about 12,000 feet of the Paradox Member beneath the crest
-of the Salt Valley anticline and only about 2,000 feet beneath the
-Courthouse syncline. Near the middle of these structures farther to the
-southeast, all the Paradox Member has been squeezed out from beneath the
-bordering synclines.
-
-    [Illustration: GRAVITY ANOMALIES OVER SALT VALLEY, along line _B-B'_
-    shown in figure 9, and relative densities and shapes of rock bodies
-    beneath. Densities are in grams per cubic centimeter. Gravity values
-    are in milligals, as shown. The standard acceleration of gravity is
-    980.665 centimeters per second per second; 1 gal is equal to 1
-    centimeter per second per second, and 1 milligal is one thousandth
-    of a gal. Modified from Case and Joesting (1972, fig. 2). (Fig. 10)]
-
-The general shape of the Salt Valley anticline is shown also by
-cross-section _B-B'_ (fig. 10), taken along the northeast-southwest line
-_B-B'_ in figure 9, which is based upon so-called gravity anomalies over
-Salt Valley. The lighter Paradox Member, having an average density of
-2.20, has a lower gravitational attraction than the heavier rocks on
-each side, which have an average density of 2.55.
-
-By this time you are doubtless wondering why prominent upfolds of the
-rocks, such as the Salt Valley anticline and associated Cache Valley
-anticline and the Seven Mile-Moab Valley anticline, now underlie
-relatively deep valleys bordered by prominent ridges. The formation of
-these valleys was not simple and involved many steps extending over a
-considerable amount of geologic time, as portrayed by Cater (1970, fig.
-13; 1972, fig. 4). For a part of the story, let us reexamine the cross
-section (fig. 8); the rest of the story will be told in the section on
-"Uplift and Erosion."
-
-Figure 8 shows that the unnamed upper member of the Hermosa Formation
-and the overlying Cutler and Moenkopi Formations are thickest beneath
-the Courthouse syncline but wedge out against the flanks of the
-anticline. Although the Chinle Formation and younger rocks appear to
-extend across the fold, and may have extended across this part of the
-fold, in Colorado all rocks older than the Jurassic Morrison wedge out
-against the flanks of the salt anticlines (Cater, 1970, p. 35) and also
-in the widest part of the Salt Valley anticline southwest of the section
-in figure 8. The salt anticlines were uplifted in a series of pulses so
-that some formations either were not deposited over the rising
-structures or were removed by erosion before deposition of the next
-younger unit. By Morrison time the supply of salt beneath the synclines
-seems to have become used up; hence, the anticline stopped rising, and
-the Morrison and younger formations were deposited across the
-structures. Thus, in figure 4, the minimum thickness of all units older
-than the Morrison is given as zero. Figure 4 shows the marine Mancos
-Shale to be the youngest rock unit exposed in the park, but the
-Mesaverde Group of Late Cretaceous age and possibly the early Tertiary
-(fig. 59) Wasatch Formation may have been deposited and later removed by
-erosion.
-
-
-
-
-                   Uplift And Erosion of The Plateau
-
-
-Next among the main events leading to the formation of landforms in the
-park was the raising and additional buckling and breaking of the Plateau
-by Earth forces partly during the Late Cretaceous but mainly during the
-early Tertiary. After uplift and deformation, the Plateau was vigorously
-attacked by various forces of erosion, and the rock materials pried
-loose or dissolved were eventually carted away to the Gulf of California
-by the ancestral Colorado River. Some idea of the enormous volume of
-rock thus removed is apparent when one looks down some 2,000 feet to the
-river from any of the high overlooks farther south, such as Dead Horse
-Point (Lohman, 1974, fig. 15). Not so apparent, however, is the fact
-that younger Mesozoic and Tertiary rocks more than 1 mile thick once
-overlaid this high plateau but have been swept away by erosion. In all,
-the river has carried thousands of cubic miles of sediment to the sea
-and is still actively at work on this gigantic earth-moving project. In
-an earlier report (Lohman, 1965, p. 42) I estimated that the rate of
-removal may have been as great as about 3 cubic miles each century. For
-a few years the bulk of the sediment was dumped into Lake Mead, but now
-Lake Powell is getting much of it. When these and other reservoirs
-ultimately become filled with sediment--for reservoirs and lakes are but
-temporary things--the Gulf of California will again become the burial
-ground.
-
-According to Cater (1970, p. 65-67), who made an intensive study of the
-salt anticlines, collapse of their crests seemingly occurred in two
-stages--the first stage following Late Cretaceous folding; the second
-following uplift of the Plateau later in the Tertiary. Solution and
-removal of salt by ground water played the leading role in the ultimate
-collapse.
-
-    [Illustration: TILTED BLOCK OF ROCKS IN CACHE VALLEY GRABEN, viewed
-    to the east toward Cache Valley from point on gravelled side road to
-    Wolfe's cabin, about half a mile east of paved road. Steep slope on
-    left composed of Jurassic Morrison Formation, hogback on top formed
-    by Dakota Sandstone of Late Cretaceous age, and gentle slopes to
-    right composed of the Mancos Shale of Late Cretaceous age. (Fig.
-    11)]
-
-As shown by Dane (1935, pl. 1, p. 121-126), collapse of the Salt Valley
-and Cache Valley anticlines was accompanied by considerable faulting and
-jointing, particularly along their northeast sides; by the upward
-intrusion of two large areas of the Paradox Member of the Hermosa
-Formation, one just northwest of the park and one in the middle of Salt
-Valley south of the campground; and by two downdropped masses of rock
-known to geologists as grabens (pronounced gr�bens)--one just northwest
-of the park and one called the Cache Valley graben, which extends both
-east and west from Salt Wash. The Cache Valley graben has preserved from
-erosion the youngest rock formations in the park, as shown in figure 11.
-
-The remarkable jointing of the rocks on the northeast limb of the Salt
-Valley anticline is shown in figure 12. All the arches in this section
-of the park were eroded through thin fins of the Slick Rock Member of
-the Entrada Sandstone, and some, like Broken Arch, figure 16, are capped
-by the Moab Member.
-
-Differences in the composition, hardness, arrangement, and thickness of
-the rock layers determine their ability to withstand the forces of
-fracturing and erosion and, hence, whether they tend to form cliffs,
-ledges, fins, or slopes. Most of the cliff- or ledge-forming rocks are
-sandstones consisting of sand deposited by wind or water and later
-cemented together by silica (SiO_{2}), calcium carbonate (CaCO_{3}), or
-one of the iron oxides (such as Fe_{2}O_{3}), but some hard, resistant
-ledges are made of limestone (calcium carbonate). The rock column (fig.
-4) shows in general how these rock formations are sculptured by erosion
-and how they protect underlying layers from more rapid erosion. The
-nearly vertical cliffs along the lower reaches of Salt and Courthouse
-Washes and the Colorado River canyon upstream from Moab consist of the
-well-cemented Wingate Sandstone protected above by the even harder
-sandstones of the Kayenta Formation. (See figs. 21, 22.) To borrow from
-an earlier report of mine (Lohman, 1965, p. 17), "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 than the Wingate, so even
-a few feet of the Kayenta * * * protect the rock beneath." In some
-places, as shown in figures 19 and 20, the overlying Navajo Sandstone
-makes up the topmost unit of the cliff.
-
-    [Illustration: JOINTED NORTHEAST FLANK OF SALT VALLEY ANTICLINE,
-    viewed westward from an airplane. Light-colored wedge in middle
-    background is Salt Valley bordered on extreme left by Klondike
-    Bluffs. Dark-colored fins and pinnacles on left, of Slick Rock
-    Member of the Entrada Sandstone, form Devils Garden. Sharp pinnacle
-    above valley is the Dark Angel. (See fig. 57.) White bands of
-    sandstone extending to foreground are composed of Moab Member of the
-    Entrada. Note vegetation in the joints. Photograph by National Park
-    Service. (Fig. 12)]
-
-Last but far from least among the factors responsible for the grandeur
-of Arches National Park and the Plateau in general is the desert
-climate, which allows one to see virtually every foot of the vividly
-colored naked rocks, and which has made possible the creation and
-preservation of such a wide variety of fantastic sculptures. A wetter
-climate would have produced a far different, smoother landscape in which
-most of the rocks and land forms would have been hidden by vegetation.
-On the Plateau the vegetation grows mainly on the high mesas and the
-narrow flood plains bordering the rivers, but scanty vegetation also
-occurs on the gentle slopes or flats.
-
-The combination of layers of sediments of different composition,
-hardness and thickness, the bending and breaking of the rocks, and the
-desert climate, has produced steep slopes having many cliffs, ledges,
-and fins with generally sharp to angular edges, rather than the subdued
-rounded forms of more humid regions.
-
-
-
-
-                  Origin And Development of The Arches
-
-
-Among the questions commonly asked by visitors are, "How do arches
-form?", "Why are some openings called windows, others arches?", "What is
-the difference, if any, between arches or windows and natural bridges,
-such as those at Natural Bridges National Monument?", and "How many
-arches are there in Arches National Park?" Before taking up the origin
-and development of arches, I shall attempt to explain the differences
-between the three types of natural rock openings named above and comment
-upon the number of arches.
-
-    [Illustration: INDEX MAP, showing localities where most of the
-    photographs were taken. Arrows point to distant views. Numbers refer
-    to figure numbers. (Fig. 13)]
-
-I believe most geologists and geographers are in general agreement with
-Cleland (1910, p. 314) that "a 'natural bridge' is a natural stone arch
-that spans a valley of erosion. A 'natural arch' is a similar structure
-which, however, does not span an erosion valley." According to this
-definition, Natural Bridges National Monument includes three true
-bridges, whereas all the larger rock openings in Arches National Park
-with which I am familiar are properly termed "arches," but some are
-called windows. If we were to distinguish between arches and windows, we
-might say that arches occur at or near the base of a rock wall, as do
-the doors of a house or building, whereas windows are found well above
-ground level. This distinction was not followed in naming the rock
-openings in the park, however; for example, Tunnel Arch (fig. 14) is
-considerably higher above the ground than North Window (figs. 37, 38) or
-South Window (fig. 39).
-
-As to the number of arches in the park, I might begin by saying that
-there is no universal agreement as to how large a rock opening must be
-to qualify as an arch. The pamphlet formerly handed to visitors entering
-the park proclaimed that "Nearly 90 arches have been discovered, and
-others are probably hidden away in remote and rugged parts of the area,"
-but the average visitor probably sees less than a third of this number.
-
-David May, Assistant Chief of Interpretation and Resource Management,
-Moab office of National Park Service (oral commun., Oct. 1973), believes
-that if only those in the park having a minimum dimension of 10 feet in
-any one direction were considered to be arches, the number would boil
-down to about 56 or 57. The most complete count of arches and other
-openings in all of southeastern Utah was made by Dale J. Stevens,
-Professor of Geography at Brigham Young University, during the period
-February through April 1973. He considered those with openings of 3 feet
-or larger and found more than 300 in southeastern Utah, of which 124 are
-in Arches National Park, although he stated that several areas of the
-park were not intensively searched because of time limitations (written
-commun., July and Sept. 1973). The 124 arches and openings are
-distributed among the several named areas of the park, as follows:
-Courthouse Towers, 13; Herdina Park, 11; The Windows section, 25;
-Delicate Arch area, 3; Fiery Furnace, 19; Devils Garden, 25; upper
-Devils Garden (northwest of Devils Garden), 14; Eagle Park, 2; and
-Klondike Bluffs, 12.
-
-Professor Stevens generally used a range finder or a steel tape to
-measure the width and height of the openings and the width and thickness
-of the spans, but estimated a few of the dimensions. In the text
-descriptions of arches or captions of figures that follow, I am
-including all or part of these measurements, without further
-acknowledgment.
-
-All the arches in the park were formed in the Entrada Sandstone, mainly
-in the Slick Rock Member but partly in the Slick Rock and Dewey Bridge
-Members, and a few in the Slick Rock Member occur not far beneath the
-base of the overlying Moab Member. The sandstone of the three members is
-composed mainly of quartz sand cemented together by calcium carbonate
-(CaCO_{3}), which also forms the mineral calcite and the rock known as
-limestone, but the Dewey Bridge Member also contains beds of sandy
-mudstone. Limestone and calcite are soluble in acid, even in weak acid
-such as carbonic acid, HHCO_{3}, also written H_{2}CO_{3}, formed by the
-solution of carbon dioxide (CO_{2}) in water. Ground water, found
-everywhere in rock openings at different depths beneath the land
-surface, contains dissolved carbon dioxide derived from decaying organic
-matter in soil, from the atmosphere, and from other sources. Even
-rainwater and snow contain a little carbon dioxide absorbed from the
-atmosphere--enough to dissolve small amounts of limestone or of calcite
-cement from sandstone. The calcite cement in the Entrada and in many
-other sandstones is unevenly distributed, however, so that all the
-cement is removed first from places that contain the least amounts, and,
-once the cement is dissolved away, the loose sand is carried away by
-gravity, wind, or water.
-
-Both nearly flat but slightly irregular beds of sandstone and relatively
-thin walls or fins of sandstone are prime targets for this differential
-erosion. Potholes, as shown in figure 18_A_, may be formed in relatively
-flat beds by the dissolving action of repeated accumulations of
-rainwater or snowmelt, even in arid regions like the Plateau.
-
-Relatively thin walls, or fins as they are called in parts of the
-Plateau including Arches, are targets for the formation of alcoves and
-caves by solution of cement and removal of sand by gravity, wind, and
-water, aided by the prying action of frost in joints, bedding planes, or
-other openings. Once a breakthrough of a wall or fin occurs, weakened
-chunks from the ceiling tend to fall, and natural arches of various
-shapes and sizes are produced. Arches form the strongest shapes for
-supporting overlying rock loads, as the rock in the arch is compressed
-toward each abutment by the heavy loads. Blocks of compressed rock
-beneath a relatively flat ceiling tend to be dislodged also by expansion
-due to release of pent-up pressure, until a strong self-supporting arch
-is formed. Release of pent-up pressure in rock walls may help also in
-initiating the formation of alcoves or caves in cliff faces. Man,
-including the ancient Greeks, Romans, Egyptians, and others, has long
-made use of arches in building bridges, aqueducts, temples, cathedrals,
-and other enduring edifices.
-
-As vividly shown in figure 12, the Entrada Sandstone on the northeast
-flank of the Salt Valley anticline has been broken by Earth forces into
-thin slabs mostly 10 to 20 feet thick between nearly parallel joints,
-but, as will be noted in the descriptions of individual arches, some
-rock walls are only 1 or 2 feet thick, whereas others are 50 feet thick
-or more. Some weak or thin slabs have weathered away, leaving the
-stronger or thicker ones as towering fins, particularly in the Fiery
-Furnace and Devils Garden areas. Jointing on a less spectacular scale
-also has broken the Entrada in areas south of Salt Valley, leaving walls
-or fins of rock.
-
-    [Illustration: TUNNEL ARCH, reached by short trail north of main
-    trail through Devils Garden. Opening is 26-1/2 feet wide and 22 feet
-    high; span is about 14 feet thick. (Fig. 14)]
-
-Although all the arches in the park were carved from the Entrada
-Sandstone, slight differences in their mode of origin or placement
-within the Entrada allow them to be grouped into three classes: (1)
-vertical arches formed in the Slick Rock Member alone or in the Slick
-Rock and Moab Members, (2) vertical arches formed mainly in the Slick
-Rock Member but partly in, and with the aid of, the incompetent
-underlying Dewey Bridge Member, and (3) horizontal arches, or so-called
-pothole arches, formed from the union of a vertical pothole and a
-horizontal cave. Hereinafter, the three members will be referred to
-alone, without reference to the Entrada.
-
-    [Illustration: "BABY ARCH," just southwest of Sheep Rock in
-    Courthouse Towers area. For details, see text. (Fig. 15)]
-
-Before giving examples of arches in each of the three classes, it is
-appropriate to remark that the arches and other erosion forms in the
-park represent but a fleeting instant in geologic time. Many of the
-pinnacles or piles of rock may be the broken remains of former arches,
-and many of the arches we see may be gone tomorrow, next year, or a few
-hundreds of years and, certainly, before many thousands of years. On the
-other hand, many new arches will form by the processes described above
-as the geologic clock ticks on.
-
-    [Illustration: BROKEN ARCH, reached by a 1/2-mile trail leading
-    northward across field that separates Fiery Furnace from Devils
-    Garden. White thin-bedded unit at top is the Moab Member, which
-    rests upon the massive salmon-colored Slick Rock Member. Opening is
-    59 feet wide and 43 feet high. (Fig. 16)]
-
-
-                           Examples of Arches
-
-Tunnel Arch (fig. 14) is a good example of an arch eroded entirely
-within the massive Slick Rock Member. Just southwest of Sheep Rock (fig.
-31) is an unnamed opening in the lower part of the Slick Rock Member
-which I call "Baby Arch," because it is one of the newest ones visible
-from the park road (fig. 15). It is only 25-1/2 feet wide and 14 feet
-high and penetrates a wall 14 feet thick. Note that the breakthrough
-probably began along the prominent recessed bedding plane at the base of
-the arch. Its youthfulness is also indicated by the sharp, angular
-breaks in the ceiling and by the pile of freshly fallen rocks. Some
-visitors have asked park personnel why they have not cleared away such
-debris! Despite its youthfulness, the ceiling has already taken on the
-shape of an arch.
-
-Broken Arch (fig. 16) was formed near the top of the Slick Rock Member
-and is strengthened and protected by the more resistant overlying Moab
-Member, which forms the upper half of the span. The crest is only 6 feet
-thick at the thinnest point and is not broken as the name seems to
-imply.
-
-Double Arch (fig. 17), "one" of the most beautiful in the park, is in
-The Windows section near the east end of the road. The southeast arch,
-which is 160 feet wide and 105 feet high, is the second largest in the
-park, but the west arch measures only 60 feet wide and 61 feet high. In
-common with most arches in The Windows section, these two arches of the
-Slick Rock Member rest upon bases of the weak, easily eroded Dewey
-Bridge Member. More rapid erosion of the Dewey Bridge undercut the
-arches and hastened their development.
-
-    [Illustration: DOUBLE ARCH, in The Windows section. (Fig. 17)]
-
-    [Illustration: PROBABLE STEPS IN FORMATION OF POTHOLE ARCH. _A_,
-    Original pothole probably formed in relatively level bed of
-    sandstone, such as this one, which is in an older rock unit--the
-    White Rim Sandstone Member of the Cutler Formation, a unit not
-    present in Arches. This pothole, which contains 4 feet of water, is
-    in nearby Canyonlands National Park (Lohman, 1974, fig. 17), just
-    north of the edge of the White Rim, about 4-1/2 miles north of the
-    confluence of the Green and Colorado Rivers. Photograph by E. N.
-    Hinrichs. _B_, Pothole is being deepened by solution while cliff is
-    receding toward pothole by weathering. _C_, As erosion continues,
-    pothole and cave in cliff face are growing deeper. _D_, Pothole Arch
-    formed by union of vertical pothole and horizontal cave. _E_,
-    Telephoto view of Pothole Arch from park road near stop 14. Visible
-    span is 90 feet across and 30 feet high. (Fig. 18)]
-
-    [Illustration: Fig. 18 B]
-
-    [Illustration: Fig. 18 C]
-
-    [Illustration: Fig. 18 D]
-
-    [Illustration: Fig. 18 E]
-
-The cause of the wavy bedding in the Dewey Bridge Member, as shown in
-figure 17 but as better shown in the frontispiece, is not known for sure
-but generally is regarded to be the result of irregular slumping during
-or just after deposition of the sediments in a body of water, caused by
-the weight of overlying sediments.
-
-The last example I shall take up is Pothole Arch (fig. 18), which
-differs from all the other examples in that this arch is roughly
-horizontal rather than vertical. Most park visitors, including me, were
-not aware of this interesting feature until after publication of the
-pamphlet "The Guide to an Auto Tour of Arches National Park," which, as
-previously noted, may be purchased at the Visitor Center. Pothole Arch
-caps a ridge high above the road half a mile northwest of Garden of
-Eden, so only those who happened to look up at the right place were
-aware of its existence.
-
-A different mode of origin than that given in the caption for figure 18
-is depicted on a poster in the Visitor Center, which shows the pothole
-being formed by a waterfall having an apparent flow rate of several
-cubic feet per second. Potholes can be formed in this manner in places
-where sufficient streamflow is available, either continuously or
-following rainstorms, but I believe the process depicted in figure 18 is
-a more likely mode of origin for Pothole Arch.
-
-
-
-
-                          How to See the Park
-
-
-As aptly stated on a poster in the Visitor Center, how to see the park
-depends in part upon the question "How long can you stay?" Inasmuch as
-the park entrance and Visitor Center are beside a through U.S. Highway
-(163), many motorists first become aware of the park's existence from
-the entrance sign, and some take time for at least a quick visit, such
-as a round trip to The Windows section, which can be made in an hour or
-so.
-
-For those who have or take more time and are able to walk at least short
-distances, a visit of 1 or 2 days is a very rewarding experience.
-Others, particularly avid shutterbugs and those with camping gear,
-profitably spend from several days to a week or more and hike all or
-most of the trails.
-
-Regardless of how long you plan to spend, I urge at least a brief stop
-at the Visitor Center, where excellent displays and a narrated slide
-show help materially in conveying just what the park has to offer. At
-the counter you can purchase a copy of "The Guide to an Auto Tour of
-Arches National Park," which explains the views from each of 25 numbered
-stops along the park road, as well as other reports describing arches or
-other parks and monuments.
-
-The park is open the year round, but, like most high deserts, it gets
-rather hot in the summer and cold enough in the winter for occasional
-snows and is sometimes closed temporarily because of heavy snowfall. The
-weather generally is ideal during the spring and fall. Even though
-summer daytime temperatures may exceed 100�F (37.8�C) and slow down
-hikers, the nights are cool enough for comfortable sleeping beneath
-ample covers.
-
-Before beginning our trip through the park proper, let us consider a
-beautiful part many people fail to realize actually belongs to the
-park--the Colorado River canyon forming the southeastern boundary.
-
-    [Illustration: Petroglyph figure]
-
-
-
-
-A Trip Through The Park
-
-
-                         Colorado River Canyon
-
-The southeastern boundary of the park for about 11 miles is the Colorado
-River, from the bridge on which U.S. Highway 163 crosses the river to a
-point upstream about half a mile below the mouth of Salt Wash.
-Illuminated night float trips down part of this reach are run during the
-summer, as noted on p. 16. Partly paved State Highway 128 follows the
-southeast side of the river for about 30 miles to Dewey Bridge, then
-goes northward about 15 miles to Cisco, where it connects with Highway
-I-70.
-
-The rocks of the Glen Canyon Group form the southernmost corner of the
-park, as shown in figure 19. About 2 miles northeast of the bridge, we
-cross the axis of the Courthouse syncline (fig. 9), which brings the
-Navajo Sandstone down nearly to river level, as shown in figure 20. The
-underlying Kayenta Formation is largely hidden by vegetation and
-alluvial deposits in this view.
-
-    [Illustration: GLEN CANYON GROUP, forming southernmost point of
-    park, as viewed across the Colorado River from State Highway 128
-    half a mile above Moab bridge carrying U.S. Highway 163. Massive
-    sandstone forming about the lower third of cliff is the Wingate
-    Sandstone, darker thin-bedded sandstones and mudstones forming
-    middle section of cliff comprise the Kayenta Formation, upper cliff
-    is the lower part of the Navajo Sandstone. Note that the saltcedar
-    (tamarisk), which lines both banks of the river, is in full bloom.
-    (Fig. 19)]
-
-    [Illustration: NAVAJO SANDSTONE CLIFFS, bordering west bank of
-    Colorado River in Courthouse syncline, from State Highway 128 about
-    2 miles above the Moab bridge. Note rounded domes at top of cliff.
-    (Fig. 20)]
-
-    [Illustration: MOUTH OF SALT WASH, viewed across Colorado River from
-    point on State Highway 128, 11 miles above Moab bridge. Dark cliffs
-    on upper right and left are of Wingate Sandstone capped by thin
-    protective cover of resistant sandstone beds of the Kayenta
-    Formation. In background Wingate is overlain by entire Kayenta
-    Formation and lower part of the Navajo Sandstone. Wingate is
-    underlain to river level by weathered slope of the Chinle Formation.
-    Water in Salt Wash is largely backwater from the bankfull river;
-    actual flow in wash generally is much less but at times reaches
-    flood proportions. (Fig. 21)]
-
-About 11 miles above the Moab bridge is the mouth of Salt Wash (fig. 1),
-as viewed from State Highway 128. (See fig. 21.) Seventeen miles above
-the bridge (east of area shown in fig. 1), we get an excellent view of
-the southeast end of the highly faulted Cache Valley anticline, as shown
-in figure 22. The background shown in the photograph formerly was the
-easternmost part of the former monument, but when the monument graduated
-to a park on November 16, 1971, this part of Cache Valley along with
-most of Dry Mesa was withdrawn from the park and put under the
-supervision of the Bureau of Land Management, also a part of the
-Department of the Interior.
-
-    [Illustration: SOUTHEAST END OF FAULTED CACHE VALLEY ANTICLINE,
-    viewed northwestward across Colorado River from a point on State
-    Highway 128, 17 miles above Moab bridge. High cliff of Wingate
-    Sandstone on left is capped by thin protective layer of the Kayenta
-    Formation. About upper third of slope below base of cliff is the
-    Chinle Formation, below which is the Moenkopi Formation extending to
-    high-water level. Note bent and broken beds on right. (Fig. 22)]
-
-As noted on page 16, part of "Run, Cougar, Run" was filmed just upstream
-from the irrigated field in the foreground of figure 22, in a wide part
-of the valley called Professor Valley (fig. 7). This valley and the
-Richardson Amphitheater on the southeast side of the river were named
-after a Professor Richardson who settled in the area in the 1880's. The
-long abandoned townsite of Richardson was 1-1/4 miles due east from the
-point from which figure 22 was taken.
-
-
-                           Headquarters Area
-
-The junction of the park road with U.S. Highway 163 is shown at the
-lower left of figure 23, and the entrance station, Visitor Center,
-parking lot, and several buildings are seen at the lower right. Several
-residences for park personnel and other buildings are shown in figure
-25. As shown in the lower part of figure 23, the geology at the park
-entrance is rather complex, as the park boundary here is partly along
-the Moab fault and partly along a branch fault--both in the Seven
-Mile-Moab Valley anticline (fig. 7). The Moab fault extends
-northwestward from Moab for more than 30 miles (McKnight, 1940, p. 120,
-121, pl. 1).
-
-As shown in figure 23, soon after leaving the checking station the park
-road begins to ascend the first of several switchbacks, and cuts first
-into the Slick Rock Member, then the Dewey Bridge Member, and finally
-the Navajo Sandstone the rest of the way to and beyond the top of the
-hill.
-
-From points a mile or so up the hill may be seen interesting features in
-several directions.[5] The view to the southwest is shown in figure 23,
-to the west are the Three Penguins (fig. 24). A good view of the Moab
-Valley is had by looking southeastward (fig. 25). A well in the Navajo
-Sandstone at the base of the hill supplies water to all the residences
-and to the Visitor Center, where a drinking fountain and modern
-restrooms are available to the public. Storage is provided by a steel
-tank hidden in a ravine above the buildings shown in figure 25.
-
-To the north the wall of Entrada Sandstone is cut by a normal fault
-(fig. 6), as shown in figure 26.
-
-    [Illustration: FAULTED SEVEN MILE-MOAB VALLEY ANTICLINE. Top, View
-    toward the southwest from park road about 1 mile above entrance
-    station. Bottom, Geologic interpretation of photograph in part after
-    McKnight (1940, pl. 1). Moab fault and branch fault (both normal
-    faults, fig. 6) unite just beyond ridge of Slick Rock Member. Total
-    vertical displacement along both faults is about 2,500 feet. H.F.,
-    unnamed upper member of Hermosa Formation; M.F., Moenkopi Formation;
-    D, downthrown side of faults; U, upthrown side. Valley fill and
-    slope wash of recent (Holocene) age obscure faults and underlying
-    rocks. The original sequence of the rocks may be visualized by
-    placing the Navajo Sandstone, the upper part of which is exposed at
-    the lower right, on top of the Kayenta Formation, the lower few feet
-    of which cap and protect the cliffs of Wingate Sandstone in the
-    background. The Pacific Northwest (gas) Pipeline mentioned on page
-    15 is buried beneath the slice of the Moenkopi Formation between the
-    two faults, which accounts for the disturbed appearance of the rock.
-    (Fig. 23)]
-
-    [Illustration: Geologic interpretation of photograph]
-
-    [Illustration: THREE PENGUINS, viewed westward from park road about
-    1 mile above entrance station. Penguins are carved in massive Slick
-    Rock Member seen resting upon thin-bedded Dewey Bridge Member. (Fig.
-    24)]
-
-    [Illustration: MOAB VALLEY, viewed southeastward from park road
-    about 1 mile above entrance station. Moab fault in about middle of
-    valley, hidden beneath recent (Holocene) valley fill and slope wash,
-    separates unnamed upper member of Hermosa Formation just above U.S.
-    Highway 163 on right from Navajo Sandstone forming hills on left and
-    ledges in foreground. Park Service residences at base of hill. White
-    patch bordering Colorado River on northwest is tailings pile of
-    Atlas Corporation's uranium mill. Moab and Spanish Valley are beyond
-    river, and south end of La Sal Mountains forms distant skyline.
-    (Fig. 25)]
-
-    [Illustration: FAULTED WALL OF ENTRADA SANDSTONE, north of park road
-    about 1 mile above entrance station. Fault is nearly vertical and
-    normal (fig. 6), but fault trace slopes steeply downward to right,
-    separating upthrown Slick Rock and Dewey Bridge Members on left from
-    downthrown Slick Rock Member on right. Light-colored rock in
-    foreground is Navajo Sandstone. Displacement probably does not
-    exceed 50 feet. (Fig. 26)]
-
-    [Illustration: PARK AVENUE, viewed to the north along trail. (Fig.
-    27)]
-
-
-                         Courthouse Towers Area
-
-About 2.3 miles from the entrance station is a turnoff and parking area
-at the south end of the Park Avenue trail (stop 2), which is about 1
-mile long and ends at another parking area 1.7 miles farther north. An
-interesting hike is best made from south to north in a downhill
-direction, and hikers generally meet the cars of relatives or friends
-awaiting them at the northern parking area. The trail begins in a canyon
-cut in the soft Dewey Bridge Member and walled by high fins of the Slick
-Rock Member (fig. 27), but farther north the canyon is floored by the
-bare Navajo Sandstone. The avenue was named from the resemblance of the
-east wall to a row of tall buildings. Atop the west wall, just to the
-left of the view in figure 27, are two balanced rocks (fig. 28). The one
-on the left, which resembles somewhat the head of an Egyptian queen, is
-offset to the right along a bedding plane, and this offset may have been
-caused by an earthquake.
-
-As we progress toward Courthouse Towers proper, lofty fins and monoliths
-lie mostly on our left, and to the right are fine distant views of the
-La Sal Mountains (stop 4). A general view of the Courthouse Towers is
-shown in figure 29, and closeups of two of the named rock
-sculptures--the Three Gossips and Sheep Rock--are shown in figures 30
-and 31. Just beyond Sheep Rock, which some think resembles the Sphinx,
-we see "Baby Arch," shown in figure 15.
-
-Five miles from the entrance station, the road crosses Courthouse Wash
-on a modern bridge (stop 6)--a distinct improvement over the two tracks
-in the sand we used in 1946. The Courthouse syncline, named after the
-wash, extends northwestward through here. (See figs. 8, 9, 20.) About a
-mile west of the bridge, Professor Stevens found another pothole arch. A
-mile and a half north of the bridge is stop 7, where attention is called
-in the booklet to the vast area of "petrified dunes" east of the road,
-which are simply dunelike exposures of the crossbedded Navajo Sandstone
-formed originally by the cementation of a vast area of sand dunes. My
-view of these was taken about 1 mile beyond the stop (fig. 32).
-
-    [Illustration: BALANCED ROCKS ON SOUTH WALL OF PARK AVENUE, at south
-    end of trail. (Fig. 28)]
-
-    [Illustration: COURTHOUSE TOWERS, viewed to the northwest from point
-    on park road about three-fourths of a mile northeast of the south
-    end of Park Avenue trail. Sandstone towers are Slick Rock Member
-    resting on Dewey Bridge Member, which also forms foreground. Three
-    Gossips at upper left, Sheep Rock just beyond. The Organ and Tower
-    of Babel are on right. (Fig. 29)]
-
-    [Illustration: THE THREE GOSSIPS, shown at upper left of figure 29.
-    (Fig. 30)]
-
-    [Illustration: SHEEP ROCK, shown on center-left skyline in figure
-    29. (Fig. 31)]
-
-West of the road between the petrified dunes and The Windows section,
-the Entrada Sandstone, particularly the Dewey Bridge Member, has been
-weathered into grotesque spires and pinnacles resembling the so-called
-"hoodoos and goblins" in Goblin Valley State Park, just north of
-Hanksville, Utah. Typical examples of "hoodoos and goblins" are shown in
-figure 33 (near stop 8). It seems reasonable to assume that some of
-these spires are the skeletal remains of former arch abutments. From
-here may be seen North and South Windows and Turret Arch on the skyline
-to the northeast (figs. 37-40).
-
-    [Illustration: PETRIFIED SAND DUNES, looking northeast from park
-    road 2.7 miles north of Courthouse Wash. The Navajo Sandstone was
-    once a huge sandpile of dunes laid down by winds during an arid
-    interval, so it is interesting to note that the irregularly
-    weathered sandstone once again resembles a pile of crossbedded
-    dunes. See also figure 35. (Fig. 32)]
-
-    [Illustration: "HOODOOS AND GOBLINS," weathered from Dewey Bridge
-    Member, viewed northwest from park road about 2-1/2 miles north of
-    Courthouse Wash. (Fig. 33)]
-
-
-                          The Windows Section
-
-The Windows section, one of the most beautiful parts of the park, once
-was the only readily accessible part of the former monument and is still
-the only collection of arches seen by many visitors who either do not
-have or do not take time to travel farther north. All the arches and
-erosion forms are on or near a high crest called Elephant Butte (Dane,
-1935, p. 126, 127), which separates Salt Valley from the Courthouse
-syncline. The ridge also marks the south edge of several minor
-anticlines and synclines termed by Dane the "Elephant Butte folds."
-
-    [Illustration: EYE OF THE WHALE, one of several arches in Herdina
-    Park, just south of jeep trail about 2 miles northwest of Balanced
-    Rock. Cut in Slick Rock Member. Front opening is 60 feet wide and 27
-    feet high, but back opening is only 35 feet wide and 11 feet high.
-    Photograph by Professor Dale J. Stevens, Brigham Young University.
-    (Fig. 34)]
-
-Guarding the approach to The Windows section is Balanced Rock (stop 9).
-As shown in the frontispiece, it is accompanied on the right by another
-balanced rock and a third one may be seen in the distance. The original
-route to The Windows section, pioneered by Goulding, passed just north
-of Balanced Rock. Traces of the old road between here and the Garden of
-Eden parking area are still visible but no longer used. To the west,
-however, a part of the old road is the starting point of a jeep trail
-leading northwestward through Herdina Park to a point near Klondike
-Bluffs, where it joins the dirt road in Salt Valley (fig. 1). Visitors
-having four-wheel-drive vehicles may wish to drive at least as far as
-Eye of The Whale (fig. 34), which is about 2 miles northwest of Balanced
-Rock. There are several picnic tables at the beginning of this jeep
-trail, but no water.
-
-    [Illustration: INTRICATE CROSSBEDS IN NAVAJO SANDSTONE, on north
-    side of road between Garden of Eden and Cove of Caves. Red crest is
-    basal part of Dewey Bridge Member. (Fig. 35)]
-
-Just beyond Balanced Rock, a branch paved road turns eastward 2-1/2
-miles to the main parking lots in The Windows section. Between the
-Garden of Eden (stop 13) and Cove of Caves are spectacular exposures of
-the Navajo Sandstone showing the crossbedding typical of the original
-dunes (fig. 35). Just east of the crossbedded Navajo Sandstone, shown in
-figure 35, we pass Cove Arch and Cove of Caves (stop 10) on the north
-side of the road (fig. 36).
-
-Just around the curve east of Cove of Caves is the first of two parking
-lots (stop 11) forming a one-way loop at the end of this branch of the
-road. From the loop may be seen the greatest concentration of readily
-accessible arches in the park, all of which are roofed by the Slick Rock
-Member and floored by the Dewey Bridge Member. Let us take the short
-paved trail from the upper lot to the southeast, where we come first to
-North Window (fig. 37). If we walk through this arch and climb the rock
-beyond (fig. 37 caption), we see one of the best views in the park (fig.
-38). A short walk south of North Window brings us to South Window (fig.
-39). The other side of this arch may be reached either by walking around
-the nearby southeast end of the fin or by walking through North Window.
-A short walk to the southwest brings us to Turret Arch--the one seen
-through North Window in figure 38. Figure 40 was taken from the
-southwest side of Turret Arch, viewed northeastward toward South Window,
-one corner of which appears at the left. Both North and South Windows
-may be seen in one photograph taken from points near Turret Arch.
-
-    [Illustration: COVE ARCH AND COVE OF CAVES, on north side of road
-    just west of Double Arch and Parade of Elephants. Arch at left and
-    three of the caves on right are roofed by Slick Rock Member and
-    floored by Dewey Bridge Member. Arch is 48-1/2 feet wide and 34 feet
-    high. In time the caves will eat through the 30-foot-thick fin and
-    become arches. Note sharp contact between Dewey Bridge Member and
-    Navajo Sandstone. (Fig. 36)]
-
-    [Illustration: NORTH WINDOW, viewed to the northeast. Large rock
-    seemingly partly blocking left end of arch actually is the southeast
-    end of a fin some 50 feet or more beyond the arch, from which figure
-    38 was taken. Arch is 93 feet wide and 51 feet high. (Fig. 37)]
-
-From the lower parking lot (stop 12), a short walk by paved trail takes
-us to spectacular Double Arch, shown in figure 17. This arch is visible
-from the parking lot but is best seen and photographed from at or near
-the end of the trail. Looking westward from near the trail's end, we see
-the Parade of Elephants, shown in figure 41. This feature is described
-on pages 16 and 17 of "The Guide to an Auto Tour of Arches National
-Park" as "whimsical stone statuary resembling a circus pachyderm parade.
-With tail in trunk, the elephants rumble toward you along a sandstone
-roadway."
-
-Ribbon Arch, on the north side of Elephant Butte, is one of the most
-delicate ones in the park (fig. 1). Although it is 50 feet wide and 55
-feet high, the rock span is only 1-1/2 feet wide and 1 foot thick.
-
-On the way back to the intersection with the main park road, we pass
-stop 14, from which may be seen Pothole Arch (fig. 18). One and one-half
-miles north of the intersection with the main road is the Panorama Point
-parking area (stop 15), which affords fine distant views of Salt and
-Cache Valleys and points beyond. A roadside exhibit portrays the gradual
-development of the Salt Valley anticline, which supplements my
-description on pages 27-32. A parking space a short distance farther
-down the hill (stop 16) provides good distant views of the Fiery
-Furnace. I tried several telephoto shots from this viewpoint, but
-preferred my closeup views, such as the one shown in figure 44.
-
-    [Illustration: LOOKING SOUTHWESTWARD THROUGH NORTH WINDOW, from fin
-    shown beyond left side of North Window in figure 37. Turret Arch
-    (fig. 40) is seen at right middle ground, south rim of Moab Valley
-    to left of arch, Colorado River canyon forms left skyline. (Fig.
-    38)]
-
-    [Illustration: SOUTH WINDOW, viewed toward northeast. Arch is 105
-    feet wide and 66 feet high. See text. (Fig. 39)]
-
-
-                           Delicate Arch Area
-
-Two and a half miles northeast of the road intersection near Balanced
-Rock, a gravelled side road leads northeastward to several points of
-considerable interest. The photograph in figure 11 was taken from this
-side road about half a mile northeast of the intersection. About 2 miles
-to the northeast, just beyond Salt Valley Wash, is a parking area (stop
-17) at the beginning of the trail past Wolfe's Bar-DX Ranch (fig. 3) to
-famed Delicate Arch, which is featured on the front cover. Although the
-trail to the arch is only 1-1/2 miles long, it crosses several hills at
-the outset, then climbs 500 feet, mostly on bare Entrada Sandstone, so
-is considered quite strenuous, particularly in hot weather. The Park
-Service advises hikers to carry water. The Walt Disney crew, cameras,
-gear, cougars, and all climbed this trail in the hottest part of the
-summer of 1971 (see p. 16), while my wife and I were working in the
-vicinity. Visitors who do not wish to make the hike may get a distant
-view of Delicate Arch by driving to a parking area (stop 18) 1.3 miles
-farther east.
-
-    [Illustration: TURRET ARCH, viewed northeast toward South Window,
-    part of which is visible on left. Small opening on right is visible
-    also in figure 38. Largest arch is 39 feet wide and 64 feet high;
-    smaller one is 12 feet wide and 13 feet high. A still smaller one,
-    not visible in the photograph, is 8 feet wide and only 4-1/2 feet
-    high. (Fig. 40)]
-
-    [Illustration: PARADE OF ELEPHANTS, viewed west from end of trail to
-    Double Arch. Two elephants are on right, one on left. (Fig. 41)]
-
-After leaving Wolfe's Ranch, the trail to Delicate Arch crosses Salt
-Wash on a suspension foot bridge (fig. 42). Just beyond the bridge, a
-short walk to the left (north) leads to the Ute petroglyphs shown in the
-lower photograph of figure 2. The most difficult part of the trail, on
-bare sandstone, is marked by cairns of stones placed at sufficient
-intervals to keep hikers from losing the barely visible trail. When the
-summit finally is reached and the last corner rounded, one suddenly sees
-perhaps the most sublime view in the park--famed Delicate Arch, framing
-part of the La Sal Mountains beyond (fig. 43). This graceful arch and
-mighty Landscape Arch (fig. 53) were considered to be in serious
-jeopardy during the era of sonic booms, but hopefully this danger now is
-past. (See p. 16-17.)
-
-It may be of interest to shutterbugs that professional photographer Hal
-Rumel lugged an 8- x 10-inch camera plus a heavy tripod and accessories
-up the steep trail to get the excellent photograph of Delicate Arch
-shown in figure 43. The late afternoon sun intensified the red somewhat,
-but my shots made earlier in the day using both 4- x 5-inch and 35-mm
-equipment resulted in unwanted shadows, even though the salmon color of
-the Slick Rock Member was more nearly normal.
-
-After leaving the junction with the side road, the main park road
-traverses slices of vertical strata squeezed between faults along the
-north side of Salt Valley, then gradually climbs out of the valley for
-about 2 miles to a parking area (stop 19), from which good views are had
-of the southeast end of Salt Valley and of the grabens in the west end
-of Cache Valley. (See fig. 11.)
-
-    [Illustration: Petroglyph figure]
-
-    [Illustration: SUSPENSION FOOT BRIDGE ACROSS SALT WASH, in front of
-    Wolfe's cabin at beginning of Delicate Arch trail. (Fig. 42)]
-
-    [Illustration: DELICATE ARCH, from end of trail 1-1/2 miles above
-    Wolfe's Ranch. The opening is 33 feet wide and 45 feet high. The
-    left abutment is only 5 feet wide at the narrowest point. The arch
-    is carved near the top of the Slick Rock Member, and the top of the
-    span, 19 feet thick, is capped by a few feet of the more resistant
-    Moab Member, as is Broken Arch (fig. 16). Photograph by Hal Rumel,
-    Salt Lake City. (Fig. 43)]
-
-
-                             Fiery Furnace
-
-About half a mile farther uphill is a parking area for viewing the
-southeastern part of the Fiery Furnace (stop 20), a vast array of
-towering fins and pinnacles of the reddish Slick Rock Member separated
-by narrow slots, vaguely resembling flames shooting skyward. The view of
-the Fiery Furnace in figure 44 was taken about 1 mile farther up the
-hill. It is not difficult to get lost among this myriad of fins and
-narrow slots, so ranger-guided tours are conducted during the summer.
-
-About 1 mile farther northwest is a parking area (stop 23) from which a
-short walk to the north end of Fiery Furnace leads to a narrow slot
-between high fins (fig. 45), along which a short sandy trail leads to a
-recess along the southwest wall containing Sand Dune Arch (fig. 46).
-This hidden arch receives sunshine only near the middle of the day and
-is a delightful, shady place to rest.
-
-From the entrance to the slot leading to Sand Dune Arch, a trail goes
-half a mile north across an open field to Broken Arch, shown in figure
-16. This field, which separates the Fiery Furnace and Devils Garden
-areas, is seen from the air in figure 12.
-
-    [Illustration: Petroglyph figure]
-
-    [Illustration: FIERY FURNACE, viewed northwest along park road about
-    1 mile northwest from stop 20. Fins and spires are of the jointed
-    Slick Rock Member (fig. 12), but the top of the Dewey Bridge Member
-    is seen to the right of the curve in the road. (Fig. 44)]
-
-    [Illustration: TRAIL TO SAND DUNE ARCH, looking northwest away from
-    arch, between towering fins of Slick Rock Member, at northwest end
-    of Fiery Furnace. Southeast end of Devils Garden in distance. (Fig.
-    45)]
-
-    [Illustration: SAND DUNE ARCH, in recess along southwest wall of
-    narrow slot shown in figure 45. Slick Rock Member. (Fig. 46)]
-
-
-                    Salt Valley and Klondike Bluffs
-
-Before proceeding to the end of the paved road, let us take an
-unimproved side road, which turns south about a third of a mile beyond
-the last stop, in order to see more of Salt Valley and to visit Klondike
-Bluffs in the northwestern part of the park. After descending 2.3 miles
-of winding road we reach the normally dry bed of Salt Valley Wash, and
-turn abruptly to the northwest. For the next three-fourths of a mile the
-"road" is simply two tracks in the loose, sandy bed of the wash, which
-obviously should not be travelled when flooded or when there is even a
-hint of rain. In dry weather, however, this road may be travelled by
-ordinary passenger car. This stretch of the wash cuts through an
-intruded block of the Paradox Member of the Hermosa Formation consisting
-mainly of gray and brown gypsum, the common salt having been dissolved
-out by ground water. Such an intrusive block of salt-bearing rock is
-known to geologists as a diapir--not to be confused with the garment
-(diaper) worn by infants.
-
-From here on the road traverses a rather uninteresting stretch of valley
-north of Salt Valley Wash. Eleven miles from the starting point, the
-road reaches an intersection from which a side road leads southwestward
-three-fourths of a mile to a parking area at the foot of Klondike
-Bluffs, which form the south side of Salt Valley. From here, one may
-make a strenuous hike over a primitive trail about 1-1/2 miles long to
-beautiful Tower Arch (fig. 47).
-
-The valley road continues northwestward from the intersection to and
-beyond the northwest end of the park and connects with roads to Crescent
-Junction, Thompson, and the Yellow Cat mining district, north of the
-park (p. 14).
-
-Let us return to the paved road and continue our tour of the park.
-
-
-                             Devils Garden
-
-Turning left (northwest) at the intersection with the paved park road,
-we enter Devils Garden--another large maze of towering red fins
-separated by narrow slots, which resembles the Fiery Furnace. After a
-third of a mile, we reach stop 24 and walk 100 feet or more to the north
-for a good view of Skyline Arch (fig. 48). This arch is very
-appropriately named, as it forms the skyline viewed either from the road
-on the south or from the campground on the north, from points south of
-the amphitheater. Less well known is the fact that Skyline Arch is
-clearly visible to the naked eye or through binoculars from stretches of
-Highway I-70 (or old U.S. Highways 6 and 50) about 11 miles to the
-north. Most arches and other erosion forms do not change appearance much
-from day to day or year to year, but some, like "Baby Arch" (fig. 15),
-show evidence of relatively recent origin. In November 1940 (Abbey,
-1971, p. 42) Skyline Arch suddenly doubled in size by the fall of a
-large rock that occupied what is now the northwest half of the arch.
-Photographs taken before and after this event appear on pages 24 and 25
-of the road guide and also in the museum at the Visitor Center.
-
-    [Illustration: TOWER ARCH, on Klondike Bluffs, viewed eastward. Arch
-    is in Slick Rock Member but tower on left, after which arch was
-    named, is capped by a protective layer of the resistant Moab Member.
-    Opening is 88 feet wide and 43 feet high. Photograph by Robert D.
-    Miller. (Fig. 47)]
-
-    [Illustration: SKYLINE ARCH, viewed north from point about 100 feet
-    north of stop 24, in Slick Rock Member. Although fins are vertical,
-    note that the strata seem to dip about 15� to the right, although
-    the actual dip is to the northeast. (See fig. 50.) (Fig. 48)]
-
-Another half mile brings us to a one-way (to right) loop at the end of
-the park road. Just beyond the beginning of the loop is a parking lot
-and very attractive picnic area containing several picnic tables shaded
-by pi�on pines at the foot of a towering red fin of the Slick Rock
-Member. Just north of this picnic ground, a paved side road leads
-eastward into a truly beautiful, well-equipped campground comprising
-both back-in and drive-through campsites for trailers, campers, or
-tents; three pairs of modern restrooms, hydrants, and drinking
-fountains; and an amphitheater, where illustrated campfire talks are
-given nightly during the summer. The east end of the campground is shown
-in figure 49.
-
-    [Illustration: CAMPGROUND IN DEVILS GARDEN, viewed northwestward
-    across turn-around at southeastern end. (Fig. 49)]
-
-Devils Garden in general and the campground in particular are on the
-crest of a ridge separating Salt Valley to the southwest from the Sagers
-Wash syncline to the northeast, which lies north of Yellow Cat Flat and
-north of the area shown in figure 1. From the higher parts of the
-campground striking views are to be had toward the north and northeast,
-particularly late in the afternoon, as shown in figure 50.
-
-    [Illustration: VIEW NORTH FROM CAMPGROUND, in late afternoon.
-    Reddish Slick Rock Member capped by light-colored Moab Member are
-    seen dipping northeastward toward Sagers Wash syncline. Book Cliffs,
-    north of Thompson, are 16 miles north on left skyline. (Fig. 50)]
-
-In about the middle of the one-way loop at the end of the park road is a
-well that supplies water to the campground from early in the spring
-until the return of freezing weather late in the fall. The well, which
-was drilled in 1962 to a depth of 900 feet, obtains a small amount of
-water from the Wingate Sandstone. No water was found in the overlying
-Navajo and Entrada Sandstones because of the pronounced dip of the rocks
-toward the northeast, which allows any water in these rocks to drain
-northeastward (Ted Arnow, written commun., 1963). Water from this well
-is pumped to a steel tank in a high part of the campground, whence it
-flows by gravity to the three sets of restrooms.
-
-    [Illustration: SOUTHEASTERN PART OF DEVILS GARDEN TRAIL, viewed
-    northwestward. Narrow slot between fins of Slick Rock Member
-    indicates local spacing of joints. (Fig. 51)]
-
-At the northwest end of the one-way loop is a large parking area for use
-by people hiking the Devils Garden trail. This trail leads to seven of
-the most interesting arches in the park, all of which are in the Slick
-Rock Member, and there are many more farther to the northwest. The
-approximate distances to the seven arches are given in the paragraphs
-that follow. The trail is paved for about 1 mile as far as Landscape
-Arch (fig. 53), but from there to Double O Arch (fig. 56) the trail is
-primitive, and the Park Service recommends rubber soles as part of the
-trail is on bare sandstone. For these reasons, many visitors hike only
-as far as Landscape Arch.
-
-    [Illustration: PINE TREE ARCH, viewed northeastward. Opening is 46
-    feet wide and 48 feet high. Fin is 30 feet thick. (Fig. 52)]
-
-Much of the trail, particularly the first part, lies in a narrow slot
-between fins of the Slick Rock Member, as shown in figure 51. After
-about half a mile, a side trail to the north leads to a Y, the
-right-hand fork of which goes to Tunnel Arch (fig. 14). The left-hand
-fork leads to Pine Tree Arch, obviously named for the pi�on pine framed
-by this arch (fig. 52).
-
-At the end of the improved part of the trail, we reach Landscape Arch
-(fig. 53), claimed by the Park Service to be the longest known natural
-arch in the world. According to Ouellette (1958) it is 291 feet long and
-118 feet high, but Professor Stevens' measurements indicate it to be 287
-feet long and 106 feet high. At its thinnest point on the right, the
-span is only 11 feet wide and 11 feet thick. In 1958 three young men
-made what was claimed to be the second known ascent of Landscape Arch,
-using ropes and other climbing gear, after which they walked across
-(Ouellette, 1958). This crossing was made with the permission of a park
-ranger, but such permission is no longer given, for the safety of both
-the arch and of would-be climbers.
-
-Wall Arch is about a quarter of a mile beyond the end of the improved
-part of the trail, and another three-fourths mile brings us to Navajo
-Arch (fig. 54) and Partition Arch (fig. 55). A distant view of Partition
-Arch may be had just before reaching Landscape Arch. Part of the
-remaining trail to Double O Arch (fig. 56) is on the top of a low
-sandstone fin, in part between somewhat higher fins and in part above
-lower slots.
-
-    [Illustration: LANDSCAPE ARCH, viewed southwestward from near end of
-    improved part of Devils Garden trail. Note that ground beneath arch
-    is covered by slope wash and near the middle with what appears to be
-    a small landslide. Slick Rock Member here is more nearly buff than
-    salmon colored, because of a smaller content of iron oxide. Fresh
-    breaks and angular blocks of stone at right abutment indicate
-    relatively recent rock falls. See text for size. (Fig. 53)]
-
-    [Illustration: NAVAJO ARCH, viewed northeastward from a branch of
-    Devils Garden trail. One of few arches having a flat soil-covered
-    floor. Opening is 40-1/2 feet wide. Photograph by National Park
-    Service. (Fig. 54)]
-
-Beautiful Double O Arch (fig. 56) is at the end of the Devils Garden
-trail about 2-1/2 miles northwest of the trailhead. About half a mile
-northwest of the trail's end is a prominent landmark called Dark Angel
-(fig. 57), which is visible in figure 12 and from the unimproved road in
-Salt Valley.
-
-    [Illustration: PARTITION ARCH, viewed southwestward from near Devils
-    Garden trail. Arch frames part of south wall of Salt Valley and, on
-    skyline, mesas south of Moab Valley. Opening is 27-1/2 feet wide and
-    26 feet high. A smaller opening to the right measures 8-1/2 feet
-    wide and 8 feet high. Photograph by Dawn E. Reed. (Fig. 55)]
-
-    [Illustration: DOUBLE O ARCH, viewed about north from northwest end
-    of Devils Garden trail. Large opening is 71 feet wide and 45 feet
-    high; small one at lower left is 21 feet wide and 11 feet high. Span
-    of large opening is 11 feet wide and 6 feet thick. Arch frames a
-    part of the Book Cliffs about 14 miles to the north. Photograph by
-    Hildegard Hamilton, Flagstaff, Ariz. (Fig. 56)]
-
-    [Illustration: DARK ANGEL, a shaft of the Slick Rock Member that is
-    an erosional remnant of a once high, narrow fin. About one-half mile
-    northwest of Double O Arch. Photograph by National Park Service.
-    (Fig. 57)]
-
-    [Illustration: "INDIAN-HEAD ARCH," in upper Devils Garden. Arch and
-    most of head are in Slick Rock Member, top of head is basal part of
-    Moab Member. Opening is 4 feet wide and 4-1/2 feet high. Photograph
-    by Professor Dale J. Stevens, Brigham Young University. (Fig. 58)]
-
-    [Illustration: GEOLOGIC TIME SPIRAL, showing the sequence, names,
-    and ages of the geologic eras, 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
-    Precambrian Era 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 Paleozoic Era. (Fig. 59)]
-
-
-
-
-                             GEOLOGIC TIME
-                          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!
-
-Professor Stevens found 14 arches in what he called upper Devils Garden,
-northwest of Double O Arch, and two arches in the northwesternmost
-extension of the park known as Eagle Park (fig. 1). One of the unnamed
-arches in upper Devils Garden is shown in figure 58. I am tentatively
-calling it "Indian-Head Arch," because of the rather obvious
-resemblance.
-
-This ends our journey through Arches National Park, but there remains
-for consideration a summary of the principal geologic events leading to
-the formation of this beautiful part of the Colorado Plateau and a brief
-comparison with the geology of other national parks and monuments on the
-Plateau.
-
-
-
-
-                      Summary of Geologic History
-
-
-Having finished our geologic trip through Arches National Park, let us
-see how the arches and other features fit into the bigger scheme of
-things--the geologic age and events of the Earth as a whole, as depicted
-in figure 59. As shown in figure 4, the rock strata still preserved in
-the park range in age from Pennsylvanian to Cretaceous, or from about
-300 million to 100 million years old--a span of about 200 million years.
-This seems an incredibly long time, until one notes that the earth is
-some 4.5 billion years old, and that our rock pile is but 1/23 or 4-1/2
-percent of the age of the Earth as a whole. Thus, in figure 59, the
-rocks exposed in the park occupy only about the left half of the top
-whorl of the spiral.
-
-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 to about 250 million years, or nearly a full whorl of the
-spiral.
-
-Deep tests for oil and gas tell us that much older rocks underlie the
-area, and we have seen that some of these played a part in shaping the
-park we see today. In addition to the Precambrian igneous and
-metamorphic rocks, there is about 2,000 feet of Paleozoic sedimentary
-rocks older than the Pennsylvanian Paradox Member of the Hermosa
-Formation, most of which was laid down in ancient seas. This includes
-strata of Cambrian, Ordovician, Devonian, Mississippian, and
-Pennsylvanian ages (fig. 59). There are some gaps in the rock record
-caused by temporary emergence of the land above sea level and erosion of
-the land surface before the land again subsided below sea level so that
-deposition could resume. Silurian rocks are absent, presumably because,
-here, the Silurian Period was dominated by erosion rather than
-deposition.
-
-While Pennsylvanian and Permian rocks were being laid down in and
-southwest of the park, a large area to the northeast, called by
-geologists the Uncompahgre Highland (because it occupied the same
-general area as part of the present Uncompahgre Plateau), rose slowly
-above sea level. Whatever Paleozoic rocks were on this rising land plus
-part of the underlying Precambrian rocks were eroded and carried by
-streams into deep basins to the northeast and southwest. Thus, while
-some marine or near-shore deposits were being laid down in and south of
-the park, thousands of feet of red beds were being laid down by streams
-between the park and what is now the Uncompahgre Plateau. During part of
-Middle Pennsylvanian time, a large area, including the park, known as
-the Paradox basin, was alternately connected to or cut off from the sea,
-so that the water was evaporated during cutoff periods and replenished
-during periods when connection with the sea resumed. In these huge
-evaporation basins were deposited the salt and gypsum plus some potash
-salts and shale that now make up the Paradox Member of the Hermosa
-Formation.
-
-Arches National Park contains four northwesterly trending major
-folds--the Salt Valley and Cache Valley salt anticlines, the Courthouse
-syncline, and the faulted Moab-Seven Mile anticline, which forms the
-southwestern border. How these folds were formed was explained on pages
-27-32. The history of their growth, however, was a long one that began
-about 300 million years ago in the Pennsylvanian and ended about 50
-million years ago in the early Tertiary. The growth of these folds
-occurred in two stages. The first stage, which involved the development
-of the salt cores of the anticlines, ended in the Jurassic with the
-beginning of Morrison time; the second stage, which involved additional
-folding that intensified the magnitude and shape of existing folds,
-occurred in the early Tertiary and was followed later by collapse of the
-salt anticlines. The formation and collapse of the Salt Valley and Cache
-Valley anticlines was accompanied by pronounced jointing (fig. 12),
-which allowed differential erosion to produce the tall fins in which the
-arches were formed.
-
-The old Uncompahgre Highland continued to shed debris into the bordering
-basins until Triassic time, when it began to be covered by a veneer of
-red sandstone and siltstone of the Chinle Formation (Lohman, 1965). The
-area remained above sea level during the Triassic Period and most, if
-not all, of the Jurassic Period, although the Jurassic Carmel Formation
-was laid down in a sea that lay just to the west.
-
-Late in the Cretaceous Period a large part of Central and Southeastern
-United States, including the eastern half of Utah, sank beneath the sea
-and received thousands of feet of mud, silt, and some sand that later
-compacted into the Mancos Shale. This formation, as well as all younger
-and some older strata, has long since been eroded from most of the park
-area, but a little of the Mancos is preserved in the Cache Valley graben
-(fig. 11), and the entire Mancos Shale and younger rocks are present in
-adjacent areas, such as the Book Cliffs north of Green River, Crescent
-Junction, and Cisco (figs. 7, 50, 56).
-
-The land rose above the sea at about the close of the Cretaceous and has
-remained above ever since, although inland basins and lakes received
-sediment during parts of the Tertiary Period. Compressive forces in the
-Earth's crust produced some gentle folding of the strata at the close of
-the Cretaceous, but more pronounced folding and some faulting occurred
-during the Eocene Epoch, when most of the Rocky Mountains took form.
-During the Miocene Epoch igneous rock welled up into older rocks to form
-the cores of the nearby La Sal, Abajo, and Henry Mountains. Additional
-uplift and some folding occurred in the Pliocene and Pleistocene Epochs.
-
-Much of the course of the Colorado River was established during the
-Miocene Epoch, with some additional adjustments in the late Pliocene and
-early Pleistocene Epochs (Hunt, C. B., 1969, p. 67). Erosion during much
-of the Tertiary Period and all of the Quaternary Period plus some
-sagging and breaking of the crest of the anticlines, brought on by
-solution and lateral squeezing of salt beds beneath the Moab-Seven Mile,
-Salt Valley, and Cache Valley anticlines, combined to produce the
-landscape as we now see it.
-
-The Precambrian rocks beneath the area are about 1.5 billion years old;
-so an enormous span of time is represented by the rocks and events in
-and beneath Canyonlands National Park.
-
-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. 59).
-
-Dinosaur N.M., with exposed rocks ranging in age from Precambrian to
-Cretaceous, covers the greatest time span (nearly 2 billion years), but
-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. and N.M. are next, with rocks ranging in age
-from Precambrian through Permian (excluding the Quaternary lava flows in
-the N.M.), but here there 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 Precambrian age with only
-a veneer of much younger rocks, obviously has but one star in its cast.
-Colorado N.M. contains rocks ranging from Precambrian to
-Cretaceous--equal to Dinosaur in this respect, but Colorado is unique in
-that all the 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.
-
-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 (fig. 19), 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, despite the fact that
-the latter is the type locality of the entire Glen Canyon Group. 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. 59), 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 same ancient people who once dwelt in Arches N.P. and
-nearby areas.
-
-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 volcanoes 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. Don't 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.
-
-
-
-
-                           Additional Reading
-
-
-Many reports covering various aspects of the area have been cited in the
-text by author and year, and these plus a few additional ones are listed
-in "Selected References." A few works of general or special interest
-should be mentioned, however.
-
-Between 1926 and 1929 the entire area now included in the park was
-mapped geologically in classic reports by Dane (1935) and by McKnight
-(1940). These men and their field assistants mapped the area by use of
-the plane-table and telescopic alidade without benefit of modern
-topographic maps or aerial photographs, except for topographic maps of
-the narrow stretch along the Colorado River mapped under the direction
-of Herron (1917). Only small sections could be reached by automobile, so
-nearly all the area was traversed using horses and mules or by hiking.
-This work plus mapping done in nearby areas to the south and to the
-north (Stokes, 1952) during the uranium boom of the mid-fifties was used
-by Williams (1964) in compiling a geologic map of the Moab quadrangle at
-a scale of 1:250,000.
-
-Several early reports on the Colorado River and its potential
-utilization contain a wealth of information and many fine photographs,
-including two by La Rue (1916, 1925) and one by Follansbee (1929).
-
-You may be interested in brief accounts of the geology of other national
-parks and monuments, or other areas of special interest, such as the
-reports on the Uinta Mountains by Hansen (1969), Mount Rainier by
-Crandell (1969), Yellowstone National Park by Keefer (1971), and ones by
-me on Colorado National Monument (Lohman, 1965) and Canyonlands National
-Park (1974).
-
-For those who wish to learn more about the science of geology, I suggest
-the textbook by Gilluly, Waters, and Woodford (1968).
-
-
-
-
-                            Acknowledgments
-
-
-I am greatly indebted to Bates Wilson, former Superintendent, and to
-former Assistant Superintendent Joe Carithers, for their splendid
-cooperation in supplying data and information; to Chuck Budge, former
-Chief Ranger; Dave May, Assistant Chief of Interpretation and Resource
-Management; Joe Miller, former Maintenance Engineer; Bob Kerr, new
-Superintendent; Maxine Newell, Park Historian and member of the staff at
-Arches National Park; Jerry Banta, former Park Ranger at Arches; and
-Carl Mikesell, Park Ranger at Arches, for their many favors.
-
-I am grateful to several colleagues and friends for the loan of
-photographs, for geologic help and data, and for reviewing this report.
-I am also deeply grateful to my wife, Ruth, for accompanying me on all
-the fieldwork and for her help and encouragement.
-
-
-
-
-                          Selected References
-
-
-  Abbey, Edward, 1971, Desert solitaire, a season in the wilderness: New
-          York, Ballantine Books, 303 p.
-  Baker, A. A., 1933, Geology and oil possibilities of the Moab
-          district, Grand and San Juan Counties, Utah: U.S. Geol. Survey
-          Bull. 841, 95 p.
-  Baker, Pearl, 1971, The Wild Bunch at Robbers Roost: New York,
-          Aberlard-Schuman, 224 p.
-  Beckwith, Frank, 1934, A group of petroglyphs near Moab, Utah: Santa
-          Fe, N. Mex., El Palacio, v. 36, p. 177-178.
-  Breed, Jack, 1947, Utah's arches of stone: Natl. Geog. Mag., p.
-          173-192, August.
-  Case, J. E., and Joesting, H. R., 1972, Regional geophysical
-          investigations in the central Colorado Plateau: U.S. Geol.
-          Survey Prof. Paper 736, 34 p.
-  Cater, F. W., 1970, Geology of the salt anticline region in
-          southwestern Colorado: U.S. Geol. Survey Prof. Paper 637, 80
-          p.
-  ---- 1972, Salt anticlines within the Paradox Basin, _in_ Geologic
-          atlas of the Rocky Mountain region, United States of America:
-          Denver, Colo., Rocky Mtn. Assoc. of Geologists, p. 137, 138,
-          fig. 4.
-  Cleland, H. F., 1910, North American natural bridges, with a
-          discussion of their origins: Geol. Soc. America Bull., v. 21,
-          p. 313-338.
-  Crandell, D. R., 1969, The geologic story of Mt. Rainier: U.S. Geol.
-          Survey Bull. 1292, 43 p.
-  Dane, C. H., 1935, Geology of the Salt Valley anticline and adjacent
-          areas, Grand County, Utah: U.S. Geol. Survey Bull. 863, 184 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.]
-  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., 1968, Principles
-          of geology [3d ed.]: San Francisco, W. R. Freeman & Co., 685
-          p.
-  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.
-  Herron, W. R., 1917, Profile surveys in the Colorado River Basin in
-          Wyoming, Utah, Colorado, and New Mexico: U.S. Geol. Survey
-          Water-Supply Paper 396, 6 p., 43 pls.
-  Hite, R. J., 1972, Pennsylvanian rocks, _in_ Geologic atlas of the
-          Rocky Mountain region, United States of America: Denver,
-          Colo., Rocky Mtn. Assoc. of Geologists, p. 133-137.
-  Hite, R. J., and Lohman, S. W., 1973, Geologic appraisal of Paradox
-          basin salt deposits for waste emplacement: U.S. Geol. Survey
-          open-file report, 75 p.
-  Hunt, Alice, 1956, Archeology of southeastern Utah, _in_ Geology and
-          economic deposits of east-central Utah: Salt Lake City,
-          Intermountain Assoc. of Petroleum Geologists, 7th Ann. Field
-          Conf., p. 13-18.
-  Hunt, C. B., 1956, Cenozoic geology of the Colorado Plateau: U.S.
-          Geol. Survey Prof. Paper 279, 99 p.
-  ---- 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, Special Issue no. 2, p. 10-15.
-  Joesting, H. R., Case, J. E., and Plouff, Donald, 1966, Regional
-          geophysical investigations of the Moab-Needles area, Utah:
-          U.S. Geol. Survey Prof. Paper 516-C, 21 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. [1972].
-  Lansford, Henry, 1972, Boatman in the desert, a passenger-carrying
-          sternwheeler in canyon country: "Empire" [magazine of the
-          Denver Post], Nov. 5, p. 18, 19.
-  La Rue, E. C., 1916, Colorado River and its utilization: U.S. Geol.
-          Survey Water-Supply Paper 395, 231 p.
-  ---- 1925, Water power and flood control of Colorado River below Green
-          River, Utah, with a foreword by Hubert Work, Secretary of the
-          Interior, p. 1-100. [Appendix A, A report on water supply, by
-          E. C. La Rue and G. F. Holbrook, p. 101-123; and Appendix B, A
-          geologic report on the inner gorge of the Grand Canyon of
-          Colorado River, by R. C. Moore, p. 125-171]: U.S. Geol. Survey
-          Water-Supply Paper 556, 176 p.
-  Lohman, S. W., 1965, 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.
-  McKnight, E. T., 1940, Geology of area between Green and Colorado
-          Rivers, Grand and San Juan Counties, Utah: U.S. Geol. Survey
-          Bull. 908, 147 p.
-  Ouellette, C. M., 1958, Over the top of Landscape Arch: Desert Mag.,
-          p. 13-16, March.
-  Pierson, Lloyd, 1960, Arches National Monument, _in_ Geology of the
-          Paradox basin fold and fault belt: Durango, Colo., Four
-          Corners Geol. Soc. Guidebook, 3d Ann. Field Conf., p. 17-21.
-  Schaafsma, Polly, 1971, Rock art of Utah: Cambridge, Mass., Harvard
-          Univ., Papers of the Peabody Museum of Archaeology and
-          Ethnology, v. 65, 169 p.
-  Stacy, J. R., 1962, Shortcut method for the preparation of
-          shaded-relief illustrations, _in_ Short papers in geology,
-          hydrology, and topography 1962: U.S. Geol. Survey Prof. Paper
-          450-D, p. D164-D165.
-  Stokes, W. L., 1952, Uranium-vanadium deposits of the Thompsons area,
-          Grand County, Utah, with emphasis on the origin of carnotite
-          ores: Utah Geol. and Mineralogical Survey Bull. 46, 51 p.,
-          December.
-  ---- 1970, Canyonlands--Geology: Naturalist, v. 21, Summer, Special
-          Issue no. 2, p. 3-9.
-  Walters, H. H., 1956, Pacific Northwest Pipeline--The scenic inch,
-          _in_ Geology and economic deposits of east-central Utah: Salt
-          Lake City, Intermountain Assoc. of Petroleum Geologists, p.
-          169-170.
-  Williams, P. L., 1964, Geology, structure, and uranium deposits of the
-          Moab quadrangle, Colorado and Utah: U.S. Geol. Survey Misc.
-          Geol. Inv. Map I-360.
-  Wilson, B. E., 1956, Arches National Monument, _in_ Geology and
-          economic deposits of east-central Utah: Salt Lake City,
-          Intermountain Assoc. of Petroleum Geologists, 7th Ann. Field
-          Conf., p. 50-51.
-  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.
-
-
-    [Illustration: Petroglyph figure]
-
-
-
-
-Footnotes
-
-
-[1]Mrs. Tanner, of Phoenix, Ariz., is the author of an earlier history
-    of Moab (her hometown). She has completed a revision entitled, "The
-    Far Country--A Regional History of Moab and La Sal, Utah," which
-    will be serialized in the Moab Times-Independent, after which it
-    will be published.
-
-[2]For the benefit of visitors from countries in which the metric system
-    is used, the following conversion factors may be helpful: 1 inch =
-    2.54 centimeters, 1 foot = 0.305 meter, 1 mile = 1.609 kilometers, 1
-    U.S. gallon = 0.00379 cubic meter.
-
-[3]Barrier Creek flows through Horseshoe Canyon in the detached unit of
-    Canyonlands National Park. The canyon walls are adorned by striking
-    pictographs (Lohman, 1974, fig. 2). "Barrier Canyon style" is named
-    after the pictographs found in Horseshoe Canyon.
-
-[4]Plastic-relief maps are no longer available from the U.S. Army Map
-    Service but may be obtained from the T. N. Hubbard Scientific Co.,
-    Box 105, Northbrook, Ill. 60062. A topographic map at a scale of
-    1:250,000 of the Moab quadrangle and similar maps at a scale of
-    1:62,500 for the Thompson, Cisco, Moab, and Castle Valley
-    quadrangles are available from the U.S. Geological Survey, Denver
-    Distribution Section, Federal Center, Denver, Colo. 80225, from the
-    Canyonlands Natural History Association at Moab, and from privately
-    owned shops where maps are sold. Most of the park is covered by the
-    Thompson and Moab quadrangles. The southern part of the park is
-    shown also on the Moab 4 NW, Moab 4 NE, and Mt. Waas 3 NW
-    quadrangles at a scale of 1:24,000. A special topographic map of
-    Arches National Park at a scale of 1:50,000 is in preparation by the
-    U.S. Geological Survey. These maps also may be obtained from the
-    above-listed sources.
-
-[5]This is numbered stop 1 in the booklet referred to earlier "The Guide
-    to an Auto Tour of Arches National Park," and corresponds to the
-    numeral one on a small sign at the roadside parking place. Some of
-    the other numbers are given in the pages that follow.
-
-
-
-
-                                 Index
-
-
-            [Italic page numbers indicate major references]
-
-
-                                   A
-                                                                     Page
-  Abajo Mountains                                                     101
-      artifacts                                                         9
-  Abbey, Edward                                                         3
-  Aborigines, occupation of area                                        9
-  Acknowledgments                                                   _105_
-  Anasazi people, petroglyphs                                          10
-  Anasazi ruins                                                    9, 103
-  Ancestral Colorado River                                             33
-  Anomalies, gravity, Salt Valley                                      32
-  Anticlines, salt                                                     31
-  Arches, broken remains                                               44
-      examples                                                       _46_
-      former abutments                                                 68
-      horizontal                                                       44
-      how they are formed                                              42
-      natural, defined                                               _40_
-      number in the park                                         40, _41_
-      origin and development                                           37
-      pothole                                                          44
-      vertical                                                     42, 44
-  Artifacts, La Sal and Abajo Mountains                                 9
-  Aspinall, Wayne, Representative                                       8
-
-
-                                    B
-  "Baby Arch"                                                  46, 63, 83
-  Balanced Rock                                                69, 70, 74
-  Banta, Jerry                                                        105
-  Bar-DX Ranch                                                 12, 13, 14
-  "Barrier Canyon style"                                               10
-  Bedding, wavy, Dewey Bridge Member                                   46
-  Beeson, Stib                                                         13
-  Beginning of a monument                                             _1_
-  Bending of rocks                                                   _24_
-  Bennett, Wallace F., Senator                                          8
-  Beroni, Pete                                                     14, 15
-  Black Canyon of the Gunnison National Monument                      102
-  Book Cliffs                                                         100
-  Breaking of rocks                                                  _24_
-  Bridge, natural, defined                                           _40_
-  Broken Arch                                                      46, 79
-  Brown-Stanton expedition, exploration                                15
-  Bryce Canyon National Park                                          103
-  Budge, Chuck                                                        105
-
-
-                                    C
-  Cache Valley                                                 56, 73, 77
-  Cache Valley anticline                         25, 32, 34, 55, 100, 101
-  Cache Valley graben                                             34, 100
-  Campground                                                           86
-      water supply                                                     87
-  Cane Creek anticline                                                 24
-  Canyon de Chelly National Monument                                  102
-  _Canyon King_                                                         8
-  Canyon Lands Section, Colorado Plateau                            9, 22
-  Canyonlands National Park                                 3, 9, 15, 102
-  Canyonlands Natural History Association                               8
-  Capitol Reef National Park                                          103
-  Carithers, Joe                                                      105
-  Carmel Formation                                                    100
-  Cassidy, Butch                                                       12
-  Caves, Entrada Sandstone                                              9
-  Cedar Breaks National Monument                                      103
-  Cedar Mesa Sandstone Member, Cutler Formation                   22, 102
-  Chinle Formation                                      32, 100, 102, 103
-  "Cisco Cutoff"                                                       16
-  Civilian Conservation Corps                                           2
-  Cliff dwellers                                                        9
-  Climate, desert                                                  35, 51
-      wetter, different landscape produced                             37
-  Collapse, salt anticlines                                        33, 34
-  Color photographs, equipment used                                     8
-  Colorado National Monument                                          102
-  Colorado Plateau, geologic formations included                      101
-      rock formations                                            103, 104
-      subdivisions                                                     18
-      uranium-vanadium mining                                          14
-  Colorado Plateaus Province                                           18
-  Colorado River, course established                                  101
-      nighttime illuminated float trip                             16, 52
-  Colorado River canyon                                      35, 51, _52_
-  Cores, salt                                                         100
-  Corral mine                                                          15
-  Courthouse syncline                     25, 30, 31, 32, 52, 63, 68, 100
-  Courthouse Towers area                                         25, _63_
-      number of arches                                                 41
-  Courthouse Wash                                        2, 3, 18, 35, 63
-  Cove Arch                                                            70
-  Cove of Caves                                                        70
-  Crossbedding, Navajo Sandstone                               63, 66, 70
-  Cutler Formation                                                32, 102
-      Cedar Mesa Sandstone Member                                      22
-      White Rim Sandstone Member                                       22
-
-
-                                    D
-  Dark Angel                                                           92
-  De Chelly Sandstone Member, Cutler Formation                        102
-  Dead Horse Point                                                     33
-  Dedication of the park                                                8
-  Delicate Arch                                        16, 25, 74, 75, 77
-  Delicate Arch area, number of arches                                 41
-  Density, average, Paradox Member                                     32
-  Deposition of rock materials, environments                         _20_
-  Desert varnish                                                       10
-  Development of the arches                                          _37_
-  Devils Garden                                    2, 5, 25, 79, _83_, 86
-      fins                                                             42
-      number of arches                                                 41
-      trail                                                        88, 92
-  Dewey Bridge                                                         52
-  Dewey Bridge Member                                              46, 63
-      Entrada Sandstone, composition                                   41
-          "hoodoos and goblins"                                        66
-          park road cutting                                            57
-          The Windows section                                          71
-          vertical arches                                              44
-  "Dewey Road"                                                         16
-  Diapir                                                               83
-  Differential erosion                                                 42
-  Dinosaur National Monument                                     101, 102
-  Dissimilarity of Arches vs. Canyonlands                          23, 24
-  Double Arch                                                   2, 46, 72
-  Double O Arch                                                90, 92, 98
-  Drainage, Arches National Park                                       18
-  Dry Mesa                                                          5, 56
-
-
-                                    E
-  Eagle Park                                                       25, 98
-      number of arches                                                 41
-  Early dwellers                                                      _9_
-  Earthquake, rock offset along bedding plane                          63
-  Egyptian queen, arch resembling                                      63
-  Eisenhower, Dwight D., Mission 66                                     4
-  Elephant Butte                                                       72
-  Elephant Butte folds                                                 68
-  Elizondo, Emmett                                                     13
-  Entrada Sandstone                                      23, 74, 102, 103
-      arches, modes of origin                                          42
-      caves                                                             9
-      cut by normal fault                                              57
-      Moab Member                                                      24
-      no water found                                                   87
-  Environments of deposition                                         _20_
-  Erosion                                                              99
-      Colorado Plateau                                               _33_
-  Evaporation basins                                                   99
-  Evaporites                                                           30
-  Eye of The Whale                                                     69
-
-
-                                    F
-  Facies changes                                                       22
-  "Father of the monument," J. W. Williams                           1, 4
-  Faults, Cache Valley anticline                                       34
-      Salt Valley anticline                                            34
-  Fiery Furnace                                      25, 42, 73, _79_, 83
-      number of arches                                                 41
-  Fins                                                             63, 79
-  Float trip, nighttime illuminated, down Colorado River               52
-  Folds                                                     _24_, 30, 100
-  Four-wheel-drive vehicles                                            69
-  Fractures                                                          _24_
-  Fremont people, occupation of area                                    9
-      pictographs                                                      10
-  Frost, prying action                                                 42
-
-
-                                    G
-  Garden of Eden                                               50, 69, 70
-  Gas exploration, deep tests                                      15, 99
-  Geographic setting                                                 _18_
-  Geologic age of rocks in park                                      _98_
-  Geologic events forming the Colorado Plateau                       _98_
-  Geologic history, summary                                          _98_
-  Geologic Time Spiral                                           101, 103
-  Geology, at the park entrance                                        57
-  Glen Canyon Group                                          52, 102, 103
-  Glen Canyon National Recreation Area                           101, 103
-  Goblin Valley State Park                                        66, 103
-  Gould, Lawrence M.                                                    1
-  Goulding, Harry, first person to drive into The Windows section   2, 69
-  Grabens                                                              34
-  Grand Canyon National Park and National Monument                    102
-  Gravity anomalies, Salt Valley                                       32
-  Green River                                                         103
-  Ground water                                                         41
-  "Guide to an Auto Tour of Arches National Park," (The)    5, 50, 51, 72
-  Gulf of California                                                   33
-
-
-                                    H
-  Hastier, (Mrs.) Hazel Wolfe                                          13
-  Headquarters area                                                  _57_
-  Henry Mountains                                                     101
-  Herdina Park                                                     25, 69
-      number of arches                                                 41
-  Hermosa Formation, Paradox Member                    23, 25, 29, 30, 32
-  History, early                                                      _9_
-      geologic, summary                                              _98_
-  "Hoodoos and goblins"                                           66, 103
-  Hoover, Herbert, proclamation                                         1
-  Horizontal arches                                                    44
-  Horseshoe Canyon, pictographs                                        10
-  Horseshoe Canyon Detached Unit of Canyonlands                        23
-  Humid regions, subdued rounded landforms                             37
-
-
-                                    I
-  Igneous rocks                                                    22, 99
-  "Indian-Head Arch"                                                   98
-  Iron in the rocks                                                    23
-  Island in the Sky                                                   102
-
-
-                                    J
-  Jeep trail                                                       69, 70
-  Johnson, Lyndon B., proclamation                                      2
-  Joints                                                    _24_, 34, 100
-
-
-                                    K
-  Kayenta Formation                                      35, 52, 102, 103
-  Kerr, Bob                                                           105
-  Klondike Bluffs                                        25, 69, _82_, 83
-      number of arches                                                 41
-
-
-                                    L
-  La Sal Mountains                                        22, 63, 77, 101
-      artifacts                                                         9
-  Lake Mead                                                            33
-  Lake Powell                                                          33
-  Land forms, formation in the park                                    33
-  Landscape Arch                                               16, 77, 88
-      second known ascent                                              90
-  Larson, Tommy                                                        13
-  Lloyd, Sherman P., Representative                                     8
-  Lohman, (Mrs.) Ruth                                                 105
-
-
-                                    M
-  Mahan, Russel L.                                                      2
-  Mancos Shale                                                    32, 100
-  Maxwell, Ross A., investigation of caves                          9, 10
-  May, David                                                      40, 105
-  Melich, Mitchell, Solicitor General                                   8
-  Mesaverde Group                                                 32, 103
-  Mesaverde National Park                                             103
-  Metamorphic rocks                                                22, 99
-  Metric unit conversion factors                                      _2_
-  Mikesell, Carl                                                      105
-  Miller, Joe                                                         105
-  Mission 66, presidential and congressional support                    4
-  Mississippi River sternwheeler replica                                8
-  Moab, uranium-vanadium mill                                          14
-  Moab bridge                                                          52
-  Moab Canyon                                                      15, 18
-  Moab fault                                                       26, 57
-  Moab Lions Club                                                    1, 8
-  "Moab Mail Road"                                                     16
-  Moab Member, Entrada Sandstone                                   24, 35
-      Entrada Sandstone, Broken Arch                                   46
-      composition                                                      41
-  "Moab panel"                                                         10
-  Moab-Spanish Valley anticline                                        26
-  Moab Valley                                                          57
-  Moab Valley-Seven Mile anticline                               100, 101
-  Moenkopi Formation                                         32, 102, 103
-  Monoliths                                                            63
-  Monument, beginning                                                 _1_
-  Monument Valley                                                101, 102
-  Morrison Formation                                              32, 101
-  Morton, Rogers C. B., Secretary of the Interior                       8
-  Moss, Frank E., Senator                                               8
-  Moss Back Member, Chinle Formation                                   15
-
-
-                                    N
-  National Park Service                                 8, 12, 40, 75, 90
-  Natural Bridges National Monument                        3, 37, 40, 102
-  Navajo Arch                                                          90
-  Navajo Sandstone                                        24, 35, 52, 103
-      canyon floor                                                     63
-      crossbedding                                             63, 66, 70
-      park road cutting                                                57
-      water supply                                                 57, 87
-  Navajo Tribe                                                        102
-  Needles section, The, Canyonlands National Park                 16, 102
-  Newell, (Mrs.) Maxine                                           12, 105
-  Nixon, Richard M., Congressional Bill                                 5
-  North Window                                                 40, 68, 71
-
-
-                                    O
-  Oil exploration                                                      15
-      Cane Creek anticline                                             24
-      deep tests                                                       99
-  Origin of the arches                                               _37_
-
-
-                                    P
-  Pacific Northwest Pipeline                                           15
-  Painted Desert                                                      102
-  Panorama Point                                                       73
-  Parade of Elephants                                                  72
-  Paradox basin                                                        23
-  Paradox Member, Hermosa Formation                23, 25, 29, 30, 82, 99
-      Hermosa Formation, average density                               32
-          upward intrusion                                             34
-  Park, a trip through                                               _52_
-      dedication                                                        8
-      how to see                                                     _50_
-      improvements                                                      4
-  Park Avenue, trail                                                   63
-  Park Service. _See_ National Park Service.
-  Partition Arch                                                       90
-  Petrified dunes                                                  63, 66
-  Petrified Forest National Park                                      102
-  Petroglyphs, Ute                                                 10, 75
-  Pictographs, Fremont people                                          10
-  Pine Tree Arch                                                       90
-  Pi�on pines                                                          86
-  Pipeline scars, Pacific Northwest Pipeline                           15
-  Plateau, uplift and erosion                                        _33_
-  Potash occurrence                                                    15
-  Pothole Arch                                                     50, 73
-  Pothole arches                                                       44
-  Powell, John Wesley, Canyonlands National Park                       15
-  Professor Valley                                                     56
-
-
-                                    R
-  Rainbow Bridge National Monument                                    103
-  Rainwater                                                        41, 42
-  Rampton, Calvin L., Utah Governor                                     8
-  Reading, additional                                               _104_
-  References, selected                                              _105_
-  Relief map, shaded, Arches National Park, described              18, 19
-  Ribbon Arch                                                          72
-  Richardson Amphitheater                                              56
-  Richardson, Professor                                                56
-  Rico Formation                                                       23
-  Rison, (Mrs.) Esther Stanley                                         13
-  Rock formations, sculptured by erosion                               35
-  Rock openings, natural, types                                        37
-  Rock types in the park                                               35
-  Roosevelt, Franklin D., proclamation                                  2
-  Rumel, Hal, photographer                                             77
-  "Run, Cougar, Run"                                           16, 56, 75
-
-
-                                    S
-  Sagers Wash syncline                                                 86
-  Salt, occurrence                                                     15
-      properties critical to formation of salt anticlines              30
-  Salt anticlines                                             30, 31, 100
-      collapse                                                     33, 34
-  Salt-bearing rock                                                    83
-  Salt rolls                                                           31
-  Salt Valley                                 2, 68, 73, 77, _82_, 83, 92
-      gravity anomalies                                                32
-  Salt Valley anticline                      25, 30, 31, 32, 73, 100, 101
-      collapse                                                         34
-      fins                                                             42
-  Salt Valley Wash                                          3, 74, 82, 83
-  Salt Wash                                                        35, 55
-      Anasazi ruins                                                     9
-      drainage                                                         18
-      grabens                                                          34
-      sandstone caves near                                             10
-  Salt Wash Sandstone Member, Morrison Formation                       14
-  San Juan Basin, natural gas                                          15
-  San Rafael Swell                                               101, 103
-  Sand Dune Arch                                                       79
-  Sandstone fins                                                   41, 42
-  Schaafsma, Polly, quoted                                         10, 12
-  Scenic drive, Moab to Cisco                                          16
-  "Scenic Inch," Pacific Northwest Pipeline                            15
-  Sedimentary rocks                                                    20
-      modes of deposition                                              99
-  Seven Mile-Moab Valley anticline                             26, 32, 57
-  Sevenmile Canyon                                                     15
-  Sheep Rock                                                           63
-  Skyline Arch                                                         83
-  Slick Rock Member, Entrada Sandstone                                 34
-      Entrada Sandstone, composition                                   41
-          high fins and pinnacles                              63, 79, 86
-          hiking trail between fins                                    90
-          park road cutting                                            57
-          salmon                                                       77
-          The Windows section                                          71
-          Tunnel Arch                                                  46
-          vertical arches                                          42, 44
-  Slumping of sediments, irregular                                     50
-  Snow                                                             41, 51
-  Sonic booms, dangers posed to arches                             16, 17
-  South Window                                                 40, 68, 71
-  Spanish explorers                                                    12
-      introduction of horses to this country                           10
-  Squaw Flat Campground                                                16
-  Stanley, Esther                                                      13
-      (Mrs.) Flora                                                     13
-      Volna                                                            13
-  Stevens, Dale J.                                     40, 41, 63, 90, 98
-  Strata, lateral changes across the park                              22
-  Sundance Kid                                                         12
-  Sunset Crater National Monument                                     103
-  Supersonic flights banned, Moab-Times Independent                    17
-  Suspension bridge, Colorado River                                    16
-
-
-                                    T
-  Tanner, (Mrs.) Faun McConkie                                          1
-  Taylor, L. L. (Bish)                                                  1
-  Temperatures                                                         51
-  "The Guide to an Auto Tour of Arches National Park"       5, 50, 51, 72
-  The Needles section, Canyonlands National Park                  16, 102
-  The Windows section                    25, 41, 46, 51, 66, _68_, 69, 70
-  Three Gossips                                                        63
-  Three Penguins                                                       57
-  Tower Arch                                                           83
-  Tunnel Arch                                                  40, 46, 90
-  Turnbow, Mary                                                         1
-  Turnbow cabin                                                        13
-  Turret Arch                                                      68, 71
-
-
-                                    U
-  Uncompahgre Highland                                        23, 99, 100
-  Uncompahgre Plateau                                              23, 99
-  Uplift, Colorado Plateau                                           _33_
-  Upper Devils Garden                                                  98
-      number of arches                                                 41
-  Uranium mines                                                        14
-  Ute petroglyphs                                                  10, 75
-
-
-                                    V
-  Vanadium mines                                                       14
-  Vegetation                                                           37
-  Vertical arches                                                  42, 44
-  Visitor Center                                           50, 51, 57, 86
-  Volz, J. Leonard                                                      8
-
-
-                                    W
-  Walker, Lester                                                       13
-  Wall Arch                                                            90
-  Walt Disney crew, "Run, Cougar, Run"                                 75
-  Wasatch Formation                                                    32
-  Water supply, Navajo Sandstone                                       57
-      to the campground                                                87
-  White Rim Sandstone Member, Cutler Formation                         22
-  Wild Bunch, The                                                      12
-  Williams, J. W.                                                    1, 4
-  Wilson, Bates                                                 1, 3, 105
-  Wilson, (Mrs.) Bates                                                  3
-  Windows, distinguished from arches                                 _40_
-  Windows section, The                       25, 46, 51, 66, _68_, 69, 70
-      number of arches                                                 41
-  Wingate Sandstone                                      35, 87, 102, 103
-  Wirth, Conrad L.                                                      4
-  Wolfe cabin                                            1, 3, 12, 13, 14
-  Wolfe, Fred                                                      12, 13
-  Wolfe, John Wesley                                               12, 13
-  Wolfe's Bar-DX Ranch                                  9, 10, 14, 74, 75
-  Wupatki National Monument                                           102
-
-
-                                    Y
-  Yellow Cat area (Thompson's area)                                    14
-  Yellow Cat Flat                                                      86
-  Yellow Cat mining district                                           83
-
-
-                                    Z
-  Zion National Park                                                  103
-
-                         *U.S. GOVERNMENT PRINTING OFFICE: 1975--679-138
-
-    [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.
-
---In the text versions only, text in italics is delimited by
-  _underscores_.
-
---The HTML version contains relative hyperlinks to a companion volume on
-  Canyonlands National Park, Gutenberg eBook #51048.
-
---A third book in the series, on Colorado National Monument, was revised
-  after this book was printed.
-
-
-
-
-
-
-
-End of the Project Gutenberg EBook of The Geologic Story of Arches National
-Park, by S. W. Lohman
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-<pre>
-
-The Project Gutenberg EBook of The Geologic Story of Arches National Park, by 
-S. W. Lohman
-
-This eBook is for the use of anyone anywhere in the United States and most
-other parts of the world at no cost and with almost no restrictions
-whatsoever.  You may copy it, give it away or re-use it under the terms of
-the Project Gutenberg License included with this eBook or online at
-www.gutenberg.org.  If you are not located in the United States, you'll have
-to check the laws of the country where you are located before using this ebook.
-
-Title: The Geologic Story of Arches National Park
-       Geological Survey Bulletin 1393
-
-Author: S. W. Lohman
-
-Illustrator: John R. Stacy
-
-Release Date: February 3, 2016 [EBook #51116]
-
-Language: English
-
-Character set encoding: UTF-8
-
-*** START OF THIS PROJECT GUTENBERG EBOOK GEOLOGIC STORY--ARCHES NATIONAL PARK ***
-
-
-
-
-Produced by Stephen Hutcheson, Dave Morgan and the Online
-Distributed Proofreading Team at http://www.pgdp.net
-
-
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-
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-
-</pre>
-
-<div id="cover" class="img">
-<img id="coverpage" src="images/cover.jpg" alt="The Geologic Story of Arches National Park" width="500" height="786" />
-</div>
-<div class="img">
-<img src="images/pmg000.jpg" alt="Geology of Arches National Park" width="600" height="292" />
-</div>
-<div class="img" id="pic1">
-<img src="images/pmg001.jpg" alt="" width="800" height="730" />
-<p class="pcap">BALANCED ROCK, guarding The
-Windows section of Arches National
-Park. Rock is Slick Rock Member of
-Entrada Sandstone resting upon crinkly
-bedded Dewey Bridge Member of
-the Entrada. White rock in foreground
-is Navajo Sandstone. La Sal Mountains
-on right skyline. (Frontispiece)</p>
-</div>
-<div class="img">
-<img src="images/pmg002.jpg" alt="Graphic Title Page" width="496" height="791" />
-</div>
-<div class="box">
-<h1><span class="smaller"><i>The Geologic Story of</i></span>
-<br /><span class="large"><span class="sc"><b>Arches</b></span></span>
-<br /><span class="small">NATIONAL PARK</span></h1>
-<p class="center">By S. W. Lohman
-<br />Graphics by
-<br />John R. Stacy</p>
-<p class="center">GEOLOGICAL SURVEY BULLETIN 1393</p>
-</div>
-<p class="tbcenter">UNITED STATES DEPARTMENT OF THE INTERIOR
-<br />ROGERS C. B. MORTON, <i>Secretary</i></p>
-<p class="center">GEOLOGICAL SURVEY
-<br />V. E. McKelvey, <i>Director</i></p>
-<div class="img">
-<img src="images/pmg003.jpg" alt="Department of the Interior &middot; March 3, 1949" width="414" height="415" />
-</div>
-<p class="center">U.S. GOVERNMENT PRINTING OFFICE: 1975</p>
-<hr />
-<dl class="undent"><dt>Library of Congress Cataloging in Publication Data</dt>
-<dt>Lohman, Stanley William, 1907-</dt>
-<dt>The geologic story of Arches National Park.</dt>
-<dt>(Geological Survey Bulletin 1393)</dt>
-<dt>Bibliography: p.</dt>
-<dt>Includes index.</dt>
-<dt>Supt. of Docs. no.: I 19.3:1393</dt>
-<dt>1. Geology&mdash;Utah&mdash;Arches National Park&mdash;Guide-books.</dt>
-<dt>2. Arches National Park, Utah&mdash;Guide-books.</dt>
-<dt>I. Title. II. Series: United States Geological Survey</dt>
-<dt>Bulletin 1393.</dt>
-<dt>QE75.B9 No. 1393 [QE170.A7] 557.3&prime;08s [557.92&prime;58]</dt>
-<dt>74-23324</dt></dl>
-<hr />
-<p class="center">For sale by the Superintendent of Documents, U. S. Government Printing Office
-<br />Washington, D. C. 20402
-<br />Stock Number 024-001-02598-1</p>
-<div class="pb" id="Page_VII">VII</div>
-<h2 class="center">Contents</h2>
-<dl class="toc">
-<dt class="small">Page</dt>
-<dt><a href="#c1">Beginning of a monument</a> 1</dt>
-<dt><a href="#c2">Graduation to a park</a> 5</dt>
-<dt><a href="#c3">Early history</a> 9</dt>
-<dd><a href="#c4">Prehistoric people</a> 9</dd>
-<dd><a href="#c5">Late arrivals</a> 12</dd>
-<dt><a href="#c6">Geographic setting</a> 18</dt>
-<dt><a href="#c7">Deposition of the rock materials</a> 20</dt>
-<dt><a href="#c8">Bending and breaking of the rocks</a> 24</dt>
-<dt><a href="#c9">Uplift and erosion of the Plateau</a> 33</dt>
-<dt><a href="#c10">Origin and development of the arches</a> 37</dt>
-<dd><a href="#c11">Examples of arches</a> 46</dd>
-<dt><a href="#c12">How to see the park</a> 50</dt>
-<dt><a href="#c13">A trip through the park</a> 52</dt>
-<dd><a href="#c14">Colorado River canyon</a> 52</dd>
-<dd><a href="#c15">Headquarters area</a> 57</dd>
-<dd><a href="#c16">Courthouse Towers area</a> 63</dd>
-<dd><a href="#c17">The Windows section</a> 68</dd>
-<dd><a href="#c18">Delicate Arch area</a> 74</dd>
-<dd><a href="#c19">Fiery Furnace</a> 79</dd>
-<dd><a href="#c20">Salt Valley and Klondike Bluffs</a> 82</dd>
-<dd><a href="#c21">Devils Garden</a> 83</dd>
-<dt><a href="#c22">Summary of geologic history</a> 98</dt>
-<dt><a href="#c23">Additional reading</a> 104</dt>
-<dt><a href="#c24">Acknowledgments</a> 105</dt>
-<dt><a href="#c25">Selected references</a> 105</dt>
-<dt><a href="#c26">Index</a> 109</dt>
-</dl>
-<div class="pb" id="Page_VIII">VIII</div>
-<h2><br /><span class="small">Figures</span></h2>
-<dl class="toc">
-<dt class="small">Page</dt>
-<dt><a href="#pic1">Frontispiece. Balanced Rock.</a></dt>
-<dt><a href="#fig1">1. Arches National Park</a> 6</dt>
-<dt><a href="#fig2">2. Rock art in Arches National Park</a> 11</dt>
-<dt><a href="#fig3">3. Wolfe&rsquo;s Bar-DX Ranch</a> 14</dt>
-<dt><a href="#fig4">4. Rock column of Arches National Park</a> 21</dt>
-<dt><a href="#fig5">5. Common types of rock folds</a> 25</dt>
-<dt><a href="#fig6">6. Common types of rock faults</a> 26</dt>
-<dt><a href="#fig7">7. Paradox basin</a> 27</dt>
-<dt><a href="#fig8">8. Geologic section across northwest end of Arches National Park</a> 28</dt>
-<dt><a href="#fig9">9. Index map of northwestern part of Arches National Park</a> 28</dt>
-<dt><a href="#fig10">10. Gravity anomalies over Salt Valley</a> 31</dt>
-<dt><a href="#fig11">11. Tilted block of rocks in Cache Valley graben</a> 34</dt>
-<dt><a href="#fig12">12. Jointed northeast flank of Salt Valley anticline</a> 36</dt>
-<dt><a href="#fig13">13. Index map</a> 38</dt>
-<dt><a href="#fig14">14. Tunnel Arch</a> 43</dt>
-<dt><a href="#fig15">15. &ldquo;Baby Arch&rdquo;</a> 44</dt>
-<dt><a href="#fig16">16. Broken Arch</a> 45</dt>
-<dt><a href="#fig17">17. Double Arch</a> 47</dt>
-<dt><a href="#fig18">18. Pothole Arch</a> 48</dt>
-<dt><a href="#fig19">19. Glen Canyon Group</a> 53</dt>
-<dt><a href="#fig20">20. Navajo Sandstone cliffs</a> 54</dt>
-<dt><a href="#fig21">21. Mouth of Salt Wash</a> 55</dt>
-<dt><a href="#fig22">22. Southeast end of faulted Cache Valley anticline</a> 56</dt>
-<dt><a href="#fig23">23. Faulted Seven Mile-Moab Valley anticline</a> 58</dt>
-<dt><a href="#fig24">24. Three Penguins</a> 59</dt>
-<dt><a href="#fig25">25. Moab Valley</a> 60</dt>
-<dt><a href="#fig26">26. Faulted wall of Entrada Sandstone</a> 61</dt>
-<dt><a href="#fig27">27. Park Avenue</a> 62</dt>
-<dt><a href="#fig28">28. Balanced rocks on south wall of Park Avenue</a> 64</dt>
-<dt><a href="#fig29">29. Courthouse Towers</a> 65</dt>
-<dt><a href="#fig30">30. The Three Gossips</a> 66</dt>
-<dt><a href="#fig31">31. Sheep Rock</a> 66</dt>
-<dt><a href="#fig32">32. Petrified sand dunes</a> 67</dt>
-<dt><a href="#fig33">33. &ldquo;Hoodoos and goblins&rdquo;</a> 68</dt>
-<dt><a href="#fig34">34. Eye of The Whale</a> 69</dt>
-<dt><a href="#fig35">35. Intricate crossbeds in Navajo Sandstone</a> 70</dt>
-<dt><a href="#fig36">36. Cove Arch and Cove of Caves</a> 71</dt>
-<dt><a href="#fig37">37. North Window</a> 72</dt>
-<dt><a href="#fig38">38. Looking southwestward through North Window</a> 73</dt>
-<dt><a href="#fig39">39. South Window</a> 74</dt>
-<dt><a href="#fig40">40. Turret Arch</a> 75</dt>
-<dt><a href="#fig41">41. Parade of Elephants</a> 76</dt>
-<dt><a href="#fig42">42. Suspension foot bridge across Salt Wash</a> 78</dt>
-<dt><a href="#fig43">43. Delicate Arch</a> 78</dt>
-<dt><a href="#fig44">44. Fiery Furnace</a> 80</dt>
-<dt><a href="#fig45">45. Trail to Sand Dune Arch</a> 81</dt>
-<dt><a href="#fig46">46. Sand Dune Arch</a> 82</dt>
-<dt><a href="#fig47">47. Tower Arch</a> 84</dt>
-<dt><a href="#fig48">48. Skyline Arch</a> 85</dt>
-<dt><a href="#fig49">49. Campground in Devils Garden</a> 86</dt>
-<dt><a href="#fig50">50. View north from campground</a> 87</dt>
-<dt><a href="#fig51">51. Southeastern part of Devils Garden trail</a> 88</dt>
-<dt><a href="#fig52">52. Pine Tree Arch</a> 89</dt>
-<dt><a href="#fig53">53. Landscape Arch</a> 91</dt>
-<dt><a href="#fig54">54. Navajo Arch</a> 92</dt>
-<dt><a href="#fig55">55. Partition Arch</a> 93</dt>
-<dt><a href="#fig56">56. Double O Arch</a> 93</dt>
-<dt><a href="#fig57">57. Dark Angel</a> 94</dt>
-<dt><a href="#fig58">58. &ldquo;Indian-Head Arch&rdquo;</a> 95</dt>
-<dt><a href="#fig59">59. Geologic time spiral</a> 96</dt>
-</dl>
-<div class="img">
-<img src="images/pmg004.jpg" alt="Petroglyph figure" width="500" height="413" />
-</div>
-<div class="pb" id="Page_1">1</div>
-<h2 class="pcap" id="c1">Beginning of a Monument</h2>
-<div class="img">
-<img src="images/pmg005.jpg" alt="" width="500" height="363" />
-</div>
-<p>According to former Superintendent Bates Wilson
-(1956), Prof. Lawrence M. Gould, of the University of
-Michigan, was the first to recognize the geologic and scenic
-values of the Arches area in eastern Utah and to urge its
-creation as a national monument. Mrs. Faun McConkie
-Tanner<a class="fn" id="fr_1" href="#fn_1">[1]</a>
-told me that Professor Gould, who had done a
-thesis problem in the nearby La Sal Mountains, was first
-taken through the area by Marv Turnbow, third owner of
-Wolfe cabin. (See <a href="#Page_12">p. 12</a>.) When Professor Gould went into
-ecstasy over the beautiful scenery, Turnbow replied, &ldquo;I
-didn&rsquo;t know there was anything unusual about it.&rdquo;</p>
-<p>Dr. J. W. Williams, generally regarded as father of the
-monument, and L. L. (Bish) Taylor, of the Moab Times-Independent,
-were the local leaders in following up on
-Gould&rsquo;s suggestion and, with the help of the Moab Lions
-Club, their efforts finally succeeded on April 12, 1929, when
-President Herbert Hoover proclaimed Arches National
-<span class="pb" id="Page_2">2</span>
-Monument, then comprising only 7 square miles.<a class="fn" id="fr_2" href="#fn_2">[2]</a> It was
-enlarged to about 53 square miles by President Franklin
-D. Roosevelt&rsquo;s Proclamation of November 25, 1938, and remained
-at nearly that size, with some boundary adjustments
-on July 22, 1960, until it was enlarged to about 130
-square miles by President Lyndon B. Johnson&rsquo;s Proclamation
-of January 20, 1969.</p>
-<p>According to Breed (1947), Harry Goulding, of Monument
-Valley, in a specially equipped car, traversed the
-rugged sand and rocks of the Arches region in the fall of
-1936 and, thus, became the first person to drive a car into
-The Windows section of Arches National Monument. Soon
-after, a bulldozer followed Harry&rsquo;s tracks and made a passable
-trail.</p>
-<p>When my family and I visited the monument in 1946,
-the entrance was about 12 miles northwest of Moab on
-U.S. Highway 163 (then U.S. 160), where Goulding&rsquo;s old
-tire tracks led eastward past a small sign reading &ldquo;Arches
-National Monument 8 miles.&rdquo; This primitive road crossed
-the sandy, normally dry Courthouse Wash and ended in
-what is now called The Windows section. At that time
-there was no water or ranger station, nor were there any
-picnic tables or other improvements within the monument
-proper, and the custodian was housed in an old barracks
-of the Civilian Conservation Corps near what is now the
-entrance, 5 miles northwest of Moab.</p>
-<p>Former Custodian Russell L. Mahan reported (oral
-commun., May 1973) that soon after our initial visit in 1946
-a 500-gallon tank was installed near Double Arch in The
-Windows section and connected to a drinking fountain and
-that two picnic tables and a pit toilet were added. At that
-time the only access to Salt Valley and what is now called
-Devils Garden was a primitive dirt road which, according
-to Breed (1947, p. 175), left old U.S. Highway 160 (now
-U.S. 163) 24 miles northwest of Moab, went 22 miles east,
-<span class="pb" id="Page_3">3</span>
-then followed Salt Valley Wash down to Wolfe cabin
-(<a href="#fig1">fig. 1</a>).</p>
-<p>According to Abbey (1971), who served as a seasonal
-ranger beginning about 1958, a sign had by then been
-erected at the crossing of Courthouse Wash which read:</p>
-<p class="center">WARNING: QUICKSAND
-<br />DO NOT CROSS WASH
-<br />WHEN WATER IS RUNNING</p>
-<p>The ranger station, his home for 6 months of the year, was
-what Abbey described as &ldquo;a little tin housetrailer.&rdquo; Nearby
-was an information display under a &ldquo;lean-to shelter.&rdquo; He
-had propane fuel for heat, cooking, and refrigeration, and a
-small gasoline-engine-driven generator for lights at night.
-His water came from the 500-gallon tank, which was filled
-at intervals from a tank truck. At that time there were
-three small dry campgrounds, each with tables, fireplaces,
-garbage cans, and pit toilets. By that time an extension of
-the dirt road led northward to Devils Garden, and some
-trails had been built and marked.</p>
-<p>Bates Wilson became Custodian of the monument in
-1949 and later became Superintendent not only of Arches
-but also of the nearby new Canyonlands National Park
-(<a href="../../51048/51048-h/51048-h.htm">Lohman, 1974</a>) and the more distant Natural Bridges
-National Monument. In the fall of 1969, Bates told me of
-some of his early experiences in the undeveloped monument,
-including the evening when 22 cars were marooned
-on the wrong (northeast) side of Courthouse Wash after
-a flash flood. Bates and his &ldquo;lone&rdquo; ranger brought ropes,
-coffee, and what food they could obtain in town after closing
-time, threw a line across the swollen stream, had a
-tourist pull a rope across, then took turns wading the
-stream with one hand on the rope and the other balancing
-supplies on his shoulder. After a fire had been built and hot
-coffee and food passed around, the spirits of the stranded
-group rose considerably, except for one irate woman
-from the East, who refused to budge from her car. Bates
-and his helper finally got the last car out about 1 a.m.,
-after the flood had subsided, and Mrs. Wilson then supplied
-lodging and more food and coffee for those who
-needed it.</p>
-<div class="pb" id="Page_4">4</div>
-<p>During and for sometime after World War II and the
-Korean War, lack of maintenance funds and personnel had
-prevented improvement of the facilities in many of our national
-parks and monuments, particularly in undeveloped
-ones like Arches. The day was saved through the wisdom
-and foresight of former Park Service Director Conrad L.
-Wirth, who saw the need and desirability of putting the
-whole &ldquo;want&rdquo; list into one attractive, marketable package.
-In the words of Everhart (1972, p. 36):</p>
-<blockquote>
-<p>Selection of a name is of course recognized as the most important
-decision in any large-scale enterprise, and here Wirth struck
-pure gold. In 1966 the Park Service would be celebrating its
-fiftieth anniversary. What a God-given target to shoot for! Why
-not produce a ten-year program, which would begin in 1956, aimed
-to bring every park up to standard by 1966&mdash;and call it Mission 66?</p>
-</blockquote>
-<p>The ensuing well-documented and cost-estimated plan
-for Mission 66 was enthusiastically backed by President
-Dwight D. Eisenhower and approved and well supported
-by Congress to the tune of more than $1 billion during
-the 10-year period. For Arches, this included a new entrance,
-Park Headquarters, Visitor Center, a museum
-boasting a bust of founder Dr. Williams, and modern
-housing for park personnel, all 5 miles northwest of Moab.
-By 1958 (Pierson, 1960) a fine new paved road between
-Park Headquarters and Balanced Rock (frontispiece) was
-completed. These badly needed improvements were followed
-by the completion of the paved road all the way to
-Devils Garden, the building of the modern campground,
-picnic facilities, and amphitheater in the Devils Garden,
-and the construction of turnouts and marked trails.</p>
-<div class="img">
-<img src="images/pmg006.jpg" alt="Petroglyph figure" width="500" height="161" />
-</div>
-<div class="pb" id="Page_5">5</div>
-<h2 class="pcap" id="c2">Graduation to a Park</h2>
-<div class="img">
-<img src="images/pmg007.jpg" alt="" width="500" height="304" />
-</div>
-<p>Arches graduated to a full-fledged national
-park when President Richard M. Nixon signed a Congressional
-Bill on November 16, 1971. The change in status
-was accompanied by boundary changes that reduced the
-area to about 114 square miles. The loss of most of Dry
-Mesa, just east of the present boundary (<a href="#fig1">fig. 1</a>), was
-offset in part by gains of new land northwest of Devils
-Garden. The present (1974) boundaries, roads, trails, and
-named features of the park are shown in <a href="#fig1">figure 1</a>.</p>
-<p>The park was virtually completed at graduation time,
-and so far this change in status has shown up mainly in
-new entrance signs, a new 1972 brochure and map, and a
-very informative &ldquo;Guide to an Auto Tour of Arches National
-Park,&rdquo; keyed to numbered signs at parking spaces.
-About all that remain to be added are new wayside exhibits,
-some boundary fences, and spur roads and trails.</p>
-<div class="pb" id="Page_6">6</div>
-<div class="img" id="fig1">
-<img src="images/map1_lr.jpg" alt="" width="600" height="766" />
-<p class="pcap">ARCHES NATIONAL PARK, showing location in Utah,
-boundaries, streams, highways and roads, trails, landforms, principal
-named features, and the city of Moab. The reader is referred
-to <a href="#fig7">figure 7</a> and to road maps issued by the State or by oil
-companies for the locations of other nearby towns and features.
-Visitors also may obtain pamphlets, from the entrance station
-or from the National Park Service office in Moab, which contain
-up-to-date maps of the park and the latest available information
-on roads, trails, campsites, and picnic sites. (Fig. 1)<br /><span class="center"><a class="abl" href="images/map1_hr.jpg">High-resolution Map</a></span></p>
-</div>
-<div class="pb" id="Page_8">8</div>
-<p>Although Arches had officially become a park in November
-1971, it was not formally dedicated until May 15, 1972.
-The ceremony began by having the Federal, State, and
-local dignitaries and other guests totaling 140 persons
-board the <i>Canyon King</i>, a 93-foot replica of a Mississippi
-River sternwheeler (Lansford, 1972; <a href="../../51048/51048-h/51048-h.htm#fig69">Lohman, 1974, fig. 69</a>),
-for its maiden voyage down the Colorado River. After
-about half an hour, the heavily laden boat became stuck
-on a sandbar, and after a 90-minute wait the passengers
-were rescued by jet boats. This delayed a luncheon at the
-Visitor Center put on by the Moab Lions Club. Following
-the luncheon, Park Superintendent Bates Wilson made a
-brief welcoming address, then introduced J. Leonard Volz,
-Director of the Midwest Region of the National Park Service,
-who served as master of ceremonies. Speakers included
-Utah Governor Calvin L. Rampton, Senator Frank
-E. Moss, a representative of Senator Wallace F. Bennett,
-Representatives Sherman P. Lloyd of Utah and Wayne
-Aspinall of Colorado, and Mitchell Melich, Solicitor General
-of the Department of Interior, representing Secretary
-Rogers C. B. Morton. After the speeches, a commemorative
-plaque, donated by the Canyonlands Natural History Association,
-was unveiled by Senator Moss and Mr. Melich.</p>
-<p>Most of the color photographs were taken by me on
-4- &times; 5-inch film in a tripod-mounted press camera, using
-lenses of several focal lengths, but a few were taken on
-35-mm film, using lenses of various focal lengths. I am
-grateful to several friends for the color photographs credited
-to them in the figure captions. The black and white
-photographs were kindly loaned from the Moab and
-Arches files of the National Park Service. The points from
-which most of the photographs were taken are shown in
-<a href="#fig13">figure 13</a>.</p>
-<div class="img">
-<img src="images/pmg010.jpg" alt="Petroglyph figure" width="500" height="129" />
-</div>
-<div class="pb" id="Page_9">9</div>
-<h2 class="pcap" id="c3">Early History</h2>
-<div class="img">
-<img src="images/pmg011.jpg" alt="" width="500" height="228" />
-</div>
-<h3 id="c4">Prehistoric People</h3>
-<p>The Canyon lands in and south of Arches were
-inhabited by cliff dwellers centuries before the first visits
-of the Spaniards and fur trappers. Projectile points and
-other artifacts found in the nearby La Sal and Abajo
-Mountains indicate occupation by aborigines during the
-period from about 3000-2000 <span class="sc">B.C.</span> to about <span class="sc">A.D.</span> 1 (Hunt,
-Alice, 1956). The Fremont people occupied the area around
-<span class="sc">A.D.</span> 850 or 900, and the Pueblo or Anasazi people from
-about <span class="sc">A.D.</span> 1075 to their departure in the late 12th century
-(Jennings, 1970). Most of the evidence for these early
-occupations has been found in and south of Canyonlands
-National Park (<a href="../../51048/51048-h/51048-h.htm">Lohman, 1974</a>), but some traces of these
-and possibly earlier cultures have been found also within
-Arches National Park.</p>
-<p>Ross A. Maxwell (National Park Service, written
-commun., 1941) investigated two caves in the Entrada
-Sandstone in the upper reaches of Salt Wash that contain
-Anasazi ruins. He mentioned that perhaps a dozen or more
-other caves should be checked for evidence of former occupation
-and, also, that he found several ancient campsites
-littered with flint chips and broken tools.</p>
-<p>One cave Maxwell explored some 5 miles north of Wolfe
-Ranch and north of the park is about 300 feet long and
-100 to 150 feet deep. It contains the remains of one or
-more ruins of a structure he thought may have covered
-much of the floor. The remaining parts of walls now are
-only two to four tiers of stones in height, although originally
-they may have been more than one story high.
-<span class="pb" id="Page_10">10</span>
-Maxwell explored a second cave on the east side of Salt
-Wash, about 2 miles north of Wolfe Ranch, which contains
-16 storage cists of adobe.</p>
-<p>The faces of many older sandstone cliffs or ledges are
-darkened by desert varnish&mdash;a natural pigment of iron
-and manganese oxides. The prehistoric inhabitants of the
-Plateau learned that effective and enduring designs, called
-petroglyphs, could be created simply by chiseling or pecking
-through the thin dark layer to reveal the buff or tan
-sandstone beneath. Most petroglyphs were created by the
-Anasazi, but those showing men mounted on horses were
-done by Ute tribesmen after the Spaniards brought in
-horses in the 1500&rsquo;s. The Fremont people and some earlier
-people painted figures on rock faces, called pictographs,
-and some of these had pecked outlines.</p>
-<p>The so-called &ldquo;Moab panel&rdquo; was described by Beckwith
-(1934, p. 177) as a petroglyph, but, as pointed out by
-Schaafsma (1971, p. 72, 73), it comprises figures having
-pecked outlines and painted bodies, which actually are
-combinations of petroglyphs and pictographs. This beautifully
-preserved group of paintings is shown in the upper
-photograph of <a href="#fig2">figure 2</a>. Mrs. Schaafsma goes on to say,
-concerning the &ldquo;Moab panel&rdquo;:</p>
-<blockquote>
-<p>The long tapered body, the antenna like headdresses, and the
-staring eyes are characteristic features of Barrier Canyon style
-figures elsewhere * * *. Of special interest here are the large
-shields held by certain figures. A visit to this site indicated that
-the shields, although apparently of some antiquity, have been
-superimposed over some of the Barrier Canyon figures. Whether
-or not this was done by the Barrier Canyon style artists themselves
-or later comers to the site is impossible to tell.</p>
-</blockquote>
-<p>Although definite proof seems lacking, she suggested
-(written commun., Nov. 3, 1973) that the &ldquo;&lsquo;Barrier Canyon
-style&rsquo;<a class="fn" id="fr_3" href="#fn_3">[3]</a> * * * is earlier than the work in the same
-region clearly attributable to the Fremont.&rdquo; Note the
-three bullet holes in and near the right-hand shield. A
-ledge above the panel that contained petroglyphs during
-her earlier visit had fallen to the base of the cliff by the
-time my wife and I inspected the panel in September 1973.</p>
-<div class="pb" id="Page_11">11</div>
-<div class="img" id="fig2">
-<img src="images/pmg012.jpg" alt="" width="800" height="526" />
-<p class="pcap">ROCK ART IN ARCHES NATIONAL PARK. A (above), &ldquo;Moab panel,&rdquo;
-on cliff of Wingate Sandstone above U.S. Highway 163 between
-Courthouse Wash and Colorado River, believed to be the work
-of &ldquo;Barrier Canyon&rdquo; style people. B (below), Petroglyphs on ledge
-of sandstone in Morrison Formation on east side of Salt Wash
-just north of Wolfe Ranch, believed to have been cut by Ute
-tribesmen. (Fig. 2)</p>
-</div>
-<div class="img">
-<img src="images/pmg013.jpg" alt="Fig. 2 B" width="800" height="568" />
-</div>
-<div class="pb" id="Page_12">12</div>
-<p>Mrs. Schaafsma believes the petroglyphs in the lower
-photograph of <a href="#fig2">figure 2</a> to be the work of Ute tribesmen,
-not only because of the horses, but also because of the
-stiff-legged appearance of the mountain sheep. Note the
-bullet hole above the panel.</p>
-<h3 id="c5">Late Arrivals</h3>
-<p>Later arrivals in and near Arches National Park included
-first Spanish explorers, then trappers, cattlemen,
-cattle rustlers and horse thieves, followed in the present
-century by oil drillers, uranium hunters, jeepsters, and
-tourists. Butch Cassidy, the Sundance Kid, and other
-members of The Wild Bunch are known to have frequented
-parts of what is now Canyonlands National Park (Baker,
-Pearl, 1971), but it is not certain whether or not any of
-them traversed what is now Arches National Park.</p>
-<p>The first settler in what is now Arches National Park
-was a Civil War veteran named John Wesley Wolfe, who
-was discharged from the Union Army about 3 weeks
-before the Battle of Bull Run because he suffered from
-varicose veins. In 1888 his doctor told him he had to leave
-Ohio for a dryer climate or he would not live 6 months, so
-he took his son Fred west and settled on a tract of 150
-acres along the west bank of Salt Wash, where his &ldquo;Wolfe
-cabin&rdquo; still stands (figs. <a href="#fig1">1</a>, <a href="#fig3">3</a>). From family letters and
-newspaper clippings compiled by Mrs. Maxine Newell and
-other members of the National Park Service (Maxine
-Newell, written commun., 1971), we learn what life in the
-area was like:</p>
-<blockquote>
-<p>We have started a cattle spread on a desert homestead. We call
-it the Bar-DX Ranch. Fred and I live in a little log
-house on the bank of a creek that is sometimes dry, sometimes
-flooded from bank to bank with roaring muddy water. We are
-surrounded with rocks&mdash;gigantic red rock formations, massive
-arches and weird figures, the like of which youve [sic] never
-seen. The desert is a hostile, demanding country, hot in summer,
-cold in winter. The Bar-DX Ranch is a day&rsquo;s ride from the nearest
-store, out of the range of schools.</p>
-</blockquote>
-<div class="pb" id="Page_13">13</div>
-<p>Although John Wolfe had promised his wife and his
-other children that he would return home the first fall
-that his cattle sales netted enough money, he and Fred
-stayed on and on, and his wife refused to go west and
-join her husband and son. Eighteen years later he sent
-money from his pension check to his daughter, Mrs. Flora
-Stanley, his son-in-law, Ed Stanley, and his two grandchildren,
-Esther and Ferol, to join him and Fred at the
-ranch. Their train was met at Thompson Springs (now
-Thompson), Utah (<a href="#fig7">fig. 7</a>), by John Wolfe for the 30-mile
-ride to the ranch by horse and wagon. Sight of the tiny
-log cabin with only a dirt floor brought tears to his daughter&rsquo;s
-eyes, but her spirits rose considerably after John
-Wolfe promised to build a new log cabin with a wooden
-floor. But the children were enchanted with this strange
-country, with the building of the new cabin, and, especially,
-with getting to go rabbit hunting with Grandpa Wolfe.
-The Stanleys stayed at the ranch until Esther was 10,
-then moved to Moab to await the arrival of their third
-child, Volna.</p>
-<p>In 1910 John Wolfe sold the Bar-DX Ranch, and the
-entire family moved to Kansas. John Wolfe later moved
-back to Ohio, and died at Etna, Licking County, on
-October 22, 1913, at the age of 84, 25 years after his doctor
-had warned him to move to a dryer climate or face an
-early death.</p>
-<p>Wolfe had sold his spread to Tommy Larson, who later
-sold it to J. Marv Turnbow and his partners, Lester Walker
-and Stib Beeson. The old log cabin gradually came to
-be known as the &ldquo;Turnbow cabin,&rdquo; and this name appeared
-on early maps of the area by the U.S. Geological Survey
-and on early pamphlets by the National Park Service,
-partly because Marv Turnbow served as a camphand in
-1927 assisting in the first detailed geologic mapping of the
-area (Dane, 1935, p. 4). In 1947 the ranch was sold to
-Emmett Elizondo, who later sold it to the Government
-for inclusion in what was then the monument.</p>
-<p>From information supplied by Wolfe&rsquo;s granddaughter,
-Mrs. Esther Stanley Rison, and his great-granddaughter,
-Mrs. Hazel Wolfe Hastler, who visited the cabin in July
-<span class="pb" id="Page_14">14</span>
-1970, the original name Wolfe cabin, or Wolfe Ranch, has
-been restored, and appears on the newer maps and pamphlets.
-(See <a href="#fig1">fig. 1</a>.) What remains of Wolfe&rsquo;s Bar-DX
-Ranch is shown in <a href="#fig3">figure 3</a>.</p>
-<div class="img" id="fig3">
-<img src="images/pmg014.jpg" alt="" width="800" height="479" />
-<p class="pcap">WOLFE&rsquo;S BAR-DX RANCH, on west bank of Salt Wash at start of
-trail to Delicate Arch. Left to right: Corral, wagon, &ldquo;new&rdquo; cabin,
-and root cellar. &ldquo;Old&rdquo; cabin, which formerly was to right of photograph,
-was washed away by a flood in 1906. (Fig. 3)</p>
-</div>
-<p>Arches National Park is surrounded by active uranium
-and vanadium mines and by many test wells for oil, gas,
-and potash; it is underlain by extensive salt and potash
-deposits. Oil and gas are produced a few miles to the north
-and east, and potash is being produced about 12 miles to
-the south (<a href="../../51048/51048-h/51048-h.htm">Lohman, 1974</a>).</p>
-<p>Uranium and vanadium have been mined on the Colorado
-Plateau since 1898 (Dane, 1935, p. 176) and in the
-Yellow Cat area (also called Thompson&rsquo;s area), just north
-of the park (<a href="#fig1">fig. 1</a>), since about 1911 (Stokes, 1952, p. 7).
-The deposits in the Yellow Cat area occur in the Salt
-Wash Sandstone Member of the Morrison Formation (<a href="#fig4">fig. 4</a>).
-According to Pete Beroni (U.S. Atomic Energy Commission,
-oral commun., August 6, 1973), some ore is still
-being produced in the Yellow Cat area, and the production
-of vanadium ore will increase as soon as the uranium mill
-at Moab is converted to also handle vanadium ore. The
-<span class="pb" id="Page_15">15</span>
-Corral and so-called Shinarump mines along the southwest
-side of Moab Canyon just north of Sevenmile Canyon (<a href="#fig1">fig. 1</a>)
-are still actively producing uranium ore from the Moss
-Back Member of the Chinle Formation, according to
-Mr. Beroni.</p>
-<p>The occurrences of salt and potash in and near the park
-and the attempts to find oil and gas nearby are discussed
-in a recent report (Hite and Lohman, 1973), and the
-deposits beneath Moab, Salt, and Cache Valleys are discussed
-in later chapters.</p>
-<p>In 1955 and 1956 the Pacific Northwest Pipeline, known
-also as the &ldquo;Scenic Inch,&rdquo; was constructed by the Pacific
-Northwest Pipeline Corp. to transmit natural gas from
-wells in the San Juan Basin of northwestern New Mexico
-for a total of 1,487 miles to the Pacific Northwest, with
-additional pickups from gas fields in northeastern Utah,
-northwestern Colorado, and southwestern Wyoming (Walters,
-1956). This 26-inch pipeline follows the general route
-of U.S. Highway 163 from Cortez, Colo., past Moab to
-Sevenmile Canyon 10 miles northwest of Moab, where it
-turns abruptly to the northeast and crosses about the middle
-of Arches National Park. It crosses the park road and
-the flat area between the Fiery Furnace and the southeast
-end of Devils Garden, but the scars are so well healed that
-most visitors are unaware of its existence unless they
-happen to look southwestward across Salt Valley, where
-the filled excavation is still visible. The filled trench also
-appears in the lower middle of <a href="#fig23">figure 23</a>.</p>
-<p>Unlike Canyonlands National Park a few miles to the
-south, Arches was not on the route of the famous early-day
-river expeditions of John Wesley Powell or of most of
-those that followed; however, the southeastern boundary
-of the park is the Colorado River, formerly the Grand,
-which was traversed by the first leg of the ill-fated Brown-Stanton
-expedition (Dellenbaugh, 1902, p. 343-369; <a href="../../51048/51048-h/51048-h.htm">Lohman, 1974</a>).</p>
-<p>The canyon of the Colorado River along the southeastern
-park boundary is deep and beautiful and is a favorite
-stretch of quiet water for boaters and floaters. Partly
-paved State Highway 128 on the east bank is a part of a
-<span class="pb" id="Page_16">16</span>
-most scenic drive from Moab to Cisco&mdash;a small railroad
-town about 32 miles northeast of the eastern border of
-<a href="#fig1">figure 1</a> (<a href="#fig7">fig. 7</a>). This road has been variously called the
-&ldquo;Moab Mail Road,&rdquo; the &ldquo;Cisco Cutoff,&rdquo; the &ldquo;Dewey
-Road,&rdquo; or the &ldquo;Dewey Bridge Road&rdquo; after an old suspension
-bridge (<a href="#fig7">fig. 7</a>) across the Colorado River at the old
-townsite of Dewey about 12 miles south of Cisco. During
-the summer this deep colorful canyon may be viewed at
-night by artificial illumination. Each evening one-half hour
-after sundown, an 80-passenger jet boat leaves a dock north
-of the highway bridge, carries passengers several miles upstream,
-then floats slowly downstream followed by a truck
-on the highway carrying 40,000 watts of searchlights
-which play back and forth on the colorful red canyon
-walls, while the passengers listen to a taped discourse. The
-entire trip requires about 2 hours.</p>
-<p>The spectacular arches and red rocks of Arches and
-vicinity have been used to advantage in making color movies
-and color TV shows. Parts of the recent Walt Disney
-film &ldquo;Run, Cougar, Run&rdquo; were filmed beneath Delicate
-Arch (<a href="#fig43">fig. 43</a>), in Professor Valley of the Colorado River
-just east of the park (<a href="#fig7">fig. 7</a>), and in other sections of the
-canyon country.</p>
-<p>Ever since military jet aircraft broke the sound barrier,
-there has been a growing number of protests from concerned
-citizens, organizations, and National Park Service
-officials concerning the dangers sonic booms have posed to
-Indian ruins and delicate erosional forms in our national
-parks and monuments, such as natural bridges, arches and
-windows, balanced rocks, and natural spires or towers.
-Many instances of damaged ruins, roads, erosional forms,
-and broken windows were reported. My wife and I can
-vouch for the destructive power of such booms, for in
-October 1969, while we were having breakfast at Squaw
-Flat Campground in The Needles section of Canyonlands
-National Park, a particularly severe blast from a low-flying
-jet not only violently rocked our jack-supported trailer
-but broke the windshield of our car.</p>
-<p>At Arches National Park, particular fear was felt for
-Landscape Arch (<a href="#fig53">fig. 53</a>), thought to be the longest natural
-<span class="pb" id="Page_17">17</span>
-stone arch in the world, and many a special round
-trip from headquarters involving 47 road miles and 2
-trail miles was made to check on the condition of this arch
-after especially loud sonic booms were heard. Finally, in
-April 1972, following a rash of newspaper and magazine
-articles that spread across the nation, the Secretary of the
-Air Force put a virtual stop to this danger by ruling
-that, except in an emergency (Moab Times-Independent,
-April 12, 1972):</p>
-<blockquote>
-<p>Supersonic flights must not only avoid passing over national
-parks, they also may not fly near them, according to the new
-regulation. For each 1,000 feet of altitude, the pilot must allow
-one-half mile between the flight path and the park boundary. The
-regulation also prohibits supersonic flights below 30,000 feet
-(over land) so the high speed planes must allow 15 miles between
-the nearest park boundary and the flight path.</p>
-</blockquote>
-<p>Let us hope that with the aid of this long-needed regulation
-and cooperation from visitors, the arches will remain
-intact for many more generations to see.</p>
-<div class="img">
-<img src="images/pmg015.jpg" alt="Petroglyph figure" width="300" height="356" />
-</div>
-<div class="pb" id="Page_18">18</div>
-<h2 class="pcap" id="c6">Geographic Setting</h2>
-<div class="img">
-<img src="images/pmg016.jpg" alt="" width="500" height="255" />
-</div>
-<p>Geologists have divided the United States into
-many provinces, each of which has distinctive geologic and
-topographic characteristics that set it apart from the
-others. One of the most intriguing and scenic of these is
-the Colorado Plateaus province, referred to in this report
-simply as the Colorado Plateau, or the Plateau (Hunt, C.
-B., 1956, <a href="#fig1">fig. 1</a>). This province, which covers some 150,000
-square miles and is not all plateaus, as we shall see, 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. Arches National Park occupies part of the Canyon
-Lands Section, one of the six subdivisions of the
-Plateau. As the names imply, the Canyon Lands Section
-of the Plateau comprises a high plateau generally ranging
-in altitude from 5,000 to 7,000 feet, which has been intricately
-dissected by literally thousands of canyons.</p>
-<p>Arches National Park is drained entirely by the Colorado
-River, whose deep canyon borders the park on the
-southeast (<a href="#fig1">fig. 1</a>). Most of the park is drained by Salt
-Wash, which enters the Colorado River just southeast of
-The Windows section, but the southwestern part is drained
-by Courthouse Wash and Moab Canyon, whose flows
-join the Colorado just west of the bridge on which U.S.
-Highway 163 crosses the river.</p>
-<p>When viewed at a distance of 1 foot, the shaded relief
-map (<a href="#fig1">fig. 1</a>) shows the general shape of the land surface
-in and near Arches National Park to the same horizontal
-scale as it would appear to a person in a spacecraft flying
-at a height of 250,000 feet, or about 47.5 miles. This map
-<span class="pb" id="Page_19">19</span>
-was prepared from part of the reverse side of a plastic-relief
-map<a class="fn" id="fr_4" href="#fn_4">[4]</a> at a scale of 1:250,000 by the U.S. Army Map
-Service of the Moab quadrangle, using a simple time- and
-money-saving method (Stacy, 1962).</p>
-<div class="img">
-<img src="images/pmg017.jpg" alt="Petroglyph figure" width="500" height="535" />
-</div>
-<div class="pb" id="Page_20">20</div>
-<h2 class="pcap" id="c7">Deposition of The Rock Materials</h2>
-<div class="img">
-<img src="images/pmg018.jpg" alt="" width="500" height="273" />
-</div>
-<p>The vivid and varied colors of the bare rocks and
-the fantastic buttes, spires, columns, alcoves, caves, arches,
-and other erosional forms of Arches National Park result
-from a fortuitous combination of geologic and climatic
-circumstances and events unequalled in most other parts
-of the world.</p>
-<p>First among these events was the piling up, layer upon
-layer, of thousands of feet of sedimentary rocks under a
-wide variety of environments. Sedimentary rocks of the
-region are composed of clay, silt, sand, and gravel carried
-and deposited by moving water; silt and sand transported
-by wind; and some materials precipitated from water solutions,
-such as limestone (calcium carbonate), dolomite
-(calcium and magnesium carbonate), gypsum (calcium
-sulfate with some water), anhydrite (calcium sulfate
-alone), common salt (sodium chloride), potash minerals,
-such as potassium chloride, and a few other less common
-types. Some of the beds were laid down in shallow seas
-that once covered the area or in lagoons and estuaries
-near the sea. Other beds were deposited by streams in inland
-basins or plains, a few were deposited in lakes, and
-the constituents of deposits like the Navajo Sandstone,
-were carried in by the wind. The character and thickness
-of the exposed sedimentary rocks and the names and ages
-assigned to them by geologists are shown in the rock
-column (<a href="#fig4">fig. 4</a>) and in the cross section (<a href="#fig8">fig. 8</a>). The history
-of their deposition is summarized on pages <a href="#Page_98">98</a>-<a href="#Page_102">102</a>.
-<a href="#fig4">Figure 4</a> was compiled mainly from generalized sections
-given by A. A. Baker (1933), Dane (1935), McKnight
-(1940), and Wright, Shawe, and Lohman (1962), and, in
-part, from Hite and Lohman (1973).</p>
-<div class="pb" id="Page_21">21</div>
-<div class="img" id="fig4">
-<img src="images/pmg019.jpg" alt="" width="1000" height="622" />
-<p class="pcap">ROCK COLUMN OF ARCHES NATIONAL PARK. Average thickness
-of units 250-1,000 feet is exaggerated two times; those less than
-250 feet, four times. 1 foot = 0.305 meter. (Fig. 4)</p>
-</div>
-<div class="ss">
-<dl class="undent"><dt>AGE (millions of yrs ago)</dt>
-<dd>GEOLOGIC AGE</dd>
-<dd class="t">NAME OF ROCK UNIT</dd>
-<dd class="t4">KIND OF ROCK AND HOW IT IS SCULPTURED BY EROSION</dd>
-<dd class="t5">THICKNESS (feet)</dd>
-<dd class="t6">NAMED FOR OCCURRENCE AT OR NEAR</dd></dl>
-<dl class="undent"><dt>100</dt>
-<dd>Late Cretaceous</dd>
-<dd class="t">Mancos Shale</dd>
-<dd class="t4">Lead-gray fossiliferous marine shale. Forms slopes.</dd>
-<dd class="t5">?</dd>
-<dd class="t6">Mancos, Colo.</dd>
-<dd class="t">Dakota Sandstone</dd>
-<dd class="t4">Conglomeratic sandstone, gray shale, carbonaceous shale, and coal. Forms ledge.</dd>
-<dd class="t5">100</dd>
-<dd class="t6">Dakota, Nebr.</dd>
-<dd class="t">Unconformity</dd>
-<dd>Late Jurassic</dd>
-<dd class="t">Morrison Fm.</dd>
-<dd class="t5">700</dd>
-<dd class="t6">Morrison, Colo.</dd>
-<dd class="t2">Brushy Basin Member</dd>
-<dd class="t4">Variegated shale, some sandstone and conglomerate, petrified wood, chert, and dinosaur bones. May contain some beds of Burro Canyon (Early Cretaceous) age.</dd>
-<dd class="t2">Salt Wash Member</dd>
-<dd class="t4">Crossbedded white and gray conglomeratic sandstone beds and lenses, locally carnotite bearing, and red and gray sandy mudstone. Forms slopes.</dd>
-<dd class="t">Unconformity</dd>
-<dt>160</dt>
-<dd class="t">San Rafael Group</dd>
-<dd class="t6">(San Rafael Swell, Utah)</dd>
-<dd class="t2">Summerville Fm.</dd>
-<dd class="t4">Thin bedded red sandstone and shale. Some cherty limestone concretions. Forms slopes.</dd>
-<dd class="t5">0-40</dd>
-<dd class="t6">Summerville Point, Utah</dd>
-<dd class="t2">Entrada Ss.</dd>
-<dd class="t6">(Entrada Point, Utah)</dd>
-<dd class="t3">Moab Member</dd>
-<dd class="t4">White, crossbedded fine-grained sandstone. Caps Slick Rock Member north of Devils Garden and Fiery Furnace and on Klondike Bluffs.</dd>
-<dd class="t5">0-100</dd>
-<dd class="t6">Moab, Utah</dd>
-<dd class="t3">Slick Rock Member</dd>
-<dd class="t4">Salmon-colored to pink and white fine-grained generally crossbedded sandstone, containing some medium- to coarse-grained sand. Generally forms cliffs or narrow fins many of which contain arches or windows.</dd>
-<dd class="t5">0-240</dd>
-<dd class="t6">Slick Rock, Colo.</dd>
-<dd class="t3">Dewey Bridge Member</dd>
-<dd class="t4">Red muddy sandstone and sandy mudstone, with contorted bedding. Forms easily eroded bases to arches in Windows Section, hence aided in their development.</dd>
-<dd class="t5">0-175</dd>
-<dd class="t6">Dewey Bridge, Utah</dd>
-<dd class="t">Unconformity</dd>
-<dt>190</dt>
-<dd>Jurassic and Triassic(?);</dd>
-<dd class="t">Glen Canyon Group</dd>
-<dd class="t2">Navajo Sandstone</dd>
-<dd class="t4">Massive crossbedded buff, gray, and white fine-grained sandstone, and local beds of gray limestone. Forms cliffs along Colorado River, floors Windows Section.</dd>
-<dd class="t5">0-350</dd>
-<dd class="t6">Navajo Country, Four Corners (Glen Canyon, U.)</dd>
-<dd>Late Triassic(?)</dd>
-<dd class="t2">Kayenta Formation</dd>
-<dd class="t4">Lavender, gray, and white lenses of sandstone, red sandy shale, and conglomerate. Contains some freshwater shells. Caps and protects cliffs of Wingate Sandstone.</dd>
-<dd class="t5">0-250</dd>
-<dd class="t6">Kayenta, Ariz.</dd>
-<dd>Late Triassic</dd>
-<dd class="t2">Wingate Sandstone</dd>
-<dd class="t4">Massive, horizontally bedded and crossbedded reddish buff fine-grained sandstone. Forms vertical cliffs along Colorado River, Cache Valley, Salt Wash, and Courthouse Wash.</dd>
-<dd class="t5">0-350</dd>
-<dd class="t6">Fort Wingate, N. Mex.</dd>
-<dt>200</dt>
-<dd class="t">Chinle Formation</dd>
-<dd class="t4">Irregularly bedded buff to red sandstone, red mudstone, limestone, and conglomerate. Lenticular sandstone and conglomerate (Moss Back Member) locally at base. Freshwater shells, petrified wood, reptile bones. Forms slopes.</dd>
-<dd class="t5">0-700</dd>
-<dd class="t6">Chinle Valley, Ariz.</dd>
-<dd class="t6">Moss Back Ridge, Utah  Unconformity</dd>
-<dd>Middle(?) and Early Triassic</dd>
-<dd class="t">Moenkopi Formation</dd>
-<dd class="t4">Thin-bedded brown shale, gray and brown sandstone, arkosic grit, and conglomerate. Crops out on southwest side of Moab Valley and in several places in Salt and Cache Valleys. Forms slopes.</dd>
-<dd class="t5">0-1,300</dd>
-<dd class="t6">Moenkopi Wash, Ariz.</dd>
-<dd class="t">Unconformity</dd>
-<dt>250</dt>
-<dd>Permian</dd>
-<dd class="t">Cutler Formation</dd>
-<dd class="t4">Chocolate brown and red sandy shale, maroon and pinkish-gray arkose and conglomerate. Lower part probably equivalent in age to Rico Formation in areas to south and east. Crops out in Moab Canyon west of Moab fault. Forms slopes.</dd>
-<dd class="t5">0-2,500</dd>
-<dd class="t6">Cutler Creek, Colo.</dd>
-<dd>Pennsylvanian</dd>
-<dd class="t">Hermosa Formation</dd>
-<dd class="t2">Unnamed upper member</dd>
-<dd class="t4">Gray marine fossiliferous sandy limestone, gray and greenish-gray sandstone and sandy shale, and red sandy shale. Exposed in ledges southwest of Moab fault in highway cut west of park entrance.</dd>
-<dd class="t5">0-1,500</dd>
-<dd class="t6">Hermosa Creek, Animas River Valley, Colo.</dd>
-<dt>300</dt>
-<dd class="t2">Paradox Member</dd>
-<dd class="t4">Salt, gypsum, and anhydrite, with black and gray shale and limestone. Few exposures in Salt and Cache Valleys. Forms slopes.</dd>
-<dd class="t5">0-11,000</dd>
-<dd class="t6">Paradox Valley, Colo.</dd>
-<dd class="t">Unconformity</dd>
-<dd>Pennsylvanian(?)</dd>
-<dd class="t">Unnamed conglomerate</dd>
-<dd class="t4">Yellow sandstone with boulders of limestone and chert containing Mississippian fossils. Exposed at two places in Salt Valley.</dd>
-<dd class="t5">?</dd></dl>
-</div>
-<div class="pb" id="Page_22">22</div>
-<p>Not exposed in the area but present far beneath the
-sedimentary cover and exposed in several places a few
-miles to the northeast are examples of the other two
-principal types of rocks&mdash;(1) igneous rocks, solidified
-from molten rock forced into or above preexisting rocks
-along cracks, joints, and faults, and (2) much older metamorphic
-rocks, formed from other preexisting rock types
-by great heat and pressure at extreme depths. Igneous
-rocks of Tertiary age (<a href="#fig59">fig. 59</a>) form the nearby La Sal
-Mountains. The particles comprising the sedimentary
-rocks in the area were derived by weathering and erosion
-of all three types of rocks in various source areas.</p>
-<p>Arches National Park and nearby Canyonlands National
-Park are both in the heart of the Canyon Lands
-Section of the Plateau; therefore, it is only reasonable to
-wonder why the differences in their general character seemingly
-outweigh their similarities. First, let us consider the
-similarities. Both parks are underlain by dominantly red
-sedimentary rocks, both parks feature unusual erosional
-forms of sandstone, and both contain beautiful natural
-arches, although the arches in Canyonlands are restricted
-almost entirely to the southeastern part of The Needles
-section and are in much older rocks than those in Arches.</p>
-<p>To be sure, differences in the rocks themselves play a
-part in the dissimilarity of the two parks, and these differences
-are of two types. First, there are lateral changes in
-the character of the strata, known to geologists as facies
-changes, brought about by differences in the environment,
-in the type of materials, and in the mode of deposition
-even within relatively short distances. Thus, during parts
-of the Permian Period while sand, later to be known as
-the Cedar Mesa and White Rim Sandstone Members of
-<span class="pb" id="Page_23">23</span>
-the Cutler Formation, was being deposited in the southern
-part of Canyonlands, red mud, silt, and sand of the Cutler
-were laid down farther north in Canyonlands
-(<a href="../../51048/51048-h/51048-h.htm#fig9">Lohman, 1974, fig. 9</a>), and similar, though somewhat coarser, beds
-of the Cutler were laid down at Arches (<a href="#fig4">fig. 4</a>). Further
-comparisons of the rock columns in the two parks show
-that while limestones of the Rico Formation were being
-deposited in a shallow sea in the southern part of Canyonlands,
-additional red mud, silt, and sand of the Cutler
-were being laid down above sea level in areas to the northeast.
-The source of the coarser materials was the ancient
-Uncompahgre Highland, which stood above sea level from
-Late Pennsylvanian time to Late Triassic time (figs. <a href="#fig7">7</a>,
-<a href="#fig59">59</a>). Although wider and longer, it occupied about the
-same position as the present Uncompahgre Plateau between
-Grand Junction and Gateway, Colo. Streams eroded
-the hard igneous and metamorphic rocks from this ancient
-landmass and dumped the material into basins to the
-northeast and southwest. The basin to the southwest, now
-called the Paradox basin (after Paradox Valley, Colo.), at
-intervals contained shallow seas and lagoons, which I will
-discuss later.</p>
-<p>Comparison of the rock columns for the two parks also
-reveals other differences. Both parks contain exposures of
-rocks as old as the Pennsylvanian Paradox Member of the
-Hermosa Formation. However, only in the Horseshoe Canyon
-Detached Unit of Canyonlands are rocks as young as
-the Jurassic Entrada Sandstone, whereas all the spectacular
-natural arches that make Arches famous were formed
-in the Entrada Sandstone, and Arches also contains several
-younger formations of Jurassic and Cretaceous age
-(<a href="#fig4">fig. 4</a>).</p>
-<p>A commonly asked question is &ldquo;Why are most of the
-rocks so red, particularly those in which the arches were
-formed?&rdquo; This can be answered with one word&mdash;iron, the
-same pigment used in rouge and in paint for barns and
-boxcars. 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
-<span class="pb" id="Page_24">24</span>
-iron ore, for the merest trace, generally only 1 to 3 percent,
-is enough to produce even the darkest shades of red. The
-white or nearly white Navajo Sandstone and the Moab
-Member of the Entrada Sandstone contain little or no iron.</p>
-<p>As pointed out by Stokes (1970, p. 3), microscopic
-examination of the colored grains of quartz or other
-minerals shows the pigment to be merely a thin coating on
-and between white or colorless particles. Sand or silt
-weathered from such rocks soon loses its color by the
-scouring action of wind or water, so that most of the sand
-dunes and sand bars are white or nearly so.</p>
-<h2 class="pcap" id="c8">Bending And Breaking of The Rocks</h2>
-<div class="img">
-<img src="images/pmg020.jpg" alt="" width="500" height="186" />
-</div>
-<p>Perhaps the greatest geologic contrast between
-these two closely adjacent parks lies in their different geologic
-structure&mdash;the kind and amount of bending and
-breaking of the once nearly flat lying strata. Consolidated
-rocks, particularly brittle types, are subject to two types
-of fracturing by Earth forces. Joints are fractures along
-which no movement has taken place. Faults are fractures
-along which there has been displacement of the two sides
-relative to one another (<a href="#fig6">fig. 6</a>). As noted in the report on
-Canyonlands National Park (<a href="../../51048/51048-h/51048-h.htm">Lohman, 1974</a>), the strata
-there, particularly along the valley of the Green River, are
-virtually flat lying or have only very gentle dips. Along the
-Colorado River above the confluence with the Green, however,
-the slightly dipping strata are interrupted by several
-gentle anticlinal and synclinal folds (<a href="#fig5">fig. 5</a>) and by at
-least one fault (<a href="#fig6">fig. 6</a>). The largest of these folds&mdash;the
-Cane Creek anticline, which crosses the Colorado River
-north of Canyonlands&mdash;has yielded oil in the past and is
-<span class="pb" id="Page_25">25</span>
-now yielding potash by solution mining of salt beds in
-the Paradox Member of the Hermosa Formation.</p>
-<div class="img" id="fig5">
-<img src="images/pmg021.jpg" alt="" width="500" height="733" />
-<p class="pcap">COMMON TYPES OF ROCK FOLDS. Top, Anticline, or upfold;
-closed anticlines are called domes. Bottom, Syncline, or downfold;
-closed synclines are called basins. From Hansen (1969, p. 31,
-108). (Fig. 5)</p>
-</div>
-<p>In strong contrast to Canyonlands, Arches National
-Park contains three northwesterly trending major folds
-and is bordered on the southwest by a fourth. The largest
-and most important are the collapsed Salt Valley and
-Cache Valley anticlines, which separate the two most
-scenic groups of arches and other erosional forms&mdash;Eagle
-Park, Devils Garden, Fiery Furnace, and Delicate Arch
-on the northeast, and Klondike Bluffs, Herdina Park, and
-The Windows section on the southwest. Farther southwest
-is the Courthouse syncline, containing the attractive
-group of erosional forms called Courthouse Towers (<a href="#fig1">fig. 1</a>).
-<span class="pb" id="Page_26">26</span>
-Finally, near the southwest edge of the park, is the
-Seven Mile-Moab Valley anticline (also known as the
-Moab-Spanish Valley anticline), whose southwest limb is
-cut off by the Moab fault (figs. <a href="#fig7">7</a>, <a href="#fig23">23</a>). The folds just
-named and the sharply contrasting geologic structures of
-the two parks are well shown on sheet 2 of the geologic
-map of the Moab quadrangle (Williams, 1964), and the
-geologic formations are shown in color on sheet 1.</p>
-<div class="img" id="fig6">
-<img src="images/pmg022.jpg" alt="" width="500" height="770" />
-<p class="pcap">COMMON TYPES OF FAULTS. Top, Normal, or gravity fault, resulting
-from tension in and lengthening of the Earth&rsquo;s crust. Bottom,
-reverse fault, resulting from compression in and shortening
-of the Earth&rsquo;s crust. Low-angle reverse faults generally are called
-overthrusts or overthrust faults. In both types, note amount of
-displacement and repetition of strata. Displacements may range
-from a few inches or feet to many thousands of feet. From Hansen
-(1969, p. 116). (Fig. 6)</p>
-</div>
-<div class="pb" id="Page_27">27</div>
-<div class="img" id="fig7">
-<img src="images/pmg023.jpg" alt="" width="600" height="756" />
-<p class="pcap">PARADOX BASIN, in southeastern Utah and southwestern Colorado,
-showing the extent of common salt and major potash deposits
-in the Paradox Member of the Hermosa Formation, and the salt
-anticlines. Adapted from Hite (1972, fig. 1B). (Fig. 7)</p>
-</div>
-<div class="pb" id="Page_28">28</div>
-<div class="img" id="fig8">
-<img src="images/pmg024.jpg" alt="" width="1000" height="376" />
-<p class="pcap">GEOLOGIC SECTION ACROSS NORTHWEST END OF ARCHES
-NATIONAL PARK, showing strata beneath Courthouse syncline and
-Salt Valley anticline. For line of section, see <a href="#fig9">figure 9</a>. Caprock
-consists of gypsum and shale, from which common salt has been
-leached by ground water, covered by alluvium. Heavy slanted lines
-near crest of anticline are faults. Adapted from Hite and Lohman
-(1973, fig. 13). (Fig. 8)</p>
-</div>
-<div class="img" id="fig9">
-<img src="images/pmg025.jpg" alt="" width="600" height="553" />
-<p class="pcap">INDEX MAP OF NORTHWESTERN PART OF ARCHES NATIONAL
-PARK, showing axes of Courthouse syncline and Salt Valley anticline,
-line of section <i>A</i>-<i>A</i>&prime; in <a href="#fig8">figure 8</a> and line of section <i>B</i>-<i>B</i>&prime; in
-<a href="#fig10">figure 10</a>. Open circles along line of section are sites of test wells
-for oil, gas, or potash. Adapted from Hite and Lohman (1973, fig. 12). (Fig. 9)</p>
-</div>
-<div class="pb" id="Page_29">29</div>
-<p>Arches National Park and most of nearby Canyonlands
-National Park lie within what geologists have termed the
-&ldquo;Paradox basin,&rdquo; which contains a remarkable assemblage
-of sediments called the Paradox Member of the Hermosa
-Formation. These deposits were laid down in shallow seas
-and lagoons during Middle Pennsylvanian time, roughly
-300 million years ago (<a href="#fig59">fig. 59</a>). As indicated in <a href="#fig4">figure 4</a>,
-the Paradox Member contains, in addition to shale and
-limestone, minerals deposited by the evaporation and concentration
-of sea water&mdash;common salt, gypsum, anhydrite,
-and potash salts. For this reason such deposits are
-<span class="pb" id="Page_30">30</span>
-collectively called evaporites. <a href="#fig7">Figure 7</a> also shows that the
-northeastern part of the Paradox basin, which is the
-deepest part, contains a series of partly alined anticlines
-which have cores of salt and, hence, are called salt anticlines.
-As might be expected, roughly alined synclines
-intervene between the anticlines, but are not shown because
-of space limitations. According to Cater (1970, p. 50):
-&ldquo;The salt anticlines of Utah and Colorado are unique
-in North America both in structure and in mode of development.&rdquo;
-To this may be added that they also are
-relatively rare in the world.</p>
-<p>A section across the Salt Valley anticline and the Courthouse
-syncline in the northwestern part of the park is
-shown in <a href="#fig8">figure 8</a>, and the axes of these structures are
-shown in <a href="#fig9">figure 9</a>.</p>
-<p>Normally, a series of roughly parallel northwestward-trending
-folds would result from shortening of a segment
-of the Earth&rsquo;s crust by compressive forces from the northeast
-and the southwest, but such does not seem to be
-the origin of these folds. The folds occur in a relatively
-narrow belt along the northeastern part of the Paradox
-basin, the deepest part, which was broken by a series of
-northwesterly trending normal faults (<a href="#fig6">fig. 6</a>) that cut the
-deep-lying Precambrian and older Paleozoic rocks (<a href="#fig8">fig. 8</a>)
-prior to the deposition of the salt-bearing Paradox Member
-of the Hermosa Formation. Movement along these
-faults continued intermittently during and after deposition
-of the Paradox, however, and resulted in the formation
-of a series of northwesterly trending ridges and
-troughs. Following Paradox time, normal sediments derived
-from a rising landmass to the northeast began to fill
-the basin. These sediments accumulated most rapidly and
-to greater thicknesses in the fault-derived troughs. Salt
-differs from normal sediments in two properties critical
-to the development of salt anticlines: first, salt is considerably
-lighter (<a href="#fig10">fig. 10</a>), and, second, salt under pressure
-will flow slowly by plastic deformation, much like ice in a
-glacier flows slowly downstream. Thus, salt in the troughs
-underlying the thicker and heavier masses of sediments
-was squeezed into the adjoining ridges, causing them to
-<span class="pb" id="Page_31">31</span>
-rise. Once started, this process tended to be self-perpetuating,
-as the flow of salt from beneath the thick masses
-of sediments in the troughs made room for the accumulation
-of still greater thicknesses of normal sediments. Consequently,
-the troughs receiving most of the sediments
-began to form downfolds, or synclines, and the ridges
-receiving little or no normal sediments began to form huge
-salt rolls that later were to become the cores of the salt
-anticlines when finally the ridges too were buried by sediments.
-Thus, the cross section (<a href="#fig8">fig. 8</a>) shows about 12,000
-feet of the Paradox Member beneath the crest of the Salt
-Valley anticline and only about 2,000 feet beneath the
-Courthouse syncline. Near the middle of these structures
-farther to the southeast, all the Paradox Member has been
-squeezed out from beneath the bordering synclines.</p>
-<div class="img" id="fig10">
-<img src="images/pmg026.jpg" alt="" width="600" height="415" />
-<p class="pcap">GRAVITY ANOMALIES OVER SALT VALLEY, along line <i>B-B&prime;</i> shown
-in <a href="#fig9">figure 9</a>, and relative densities and shapes of rock bodies beneath.
-Densities are in grams per cubic centimeter. Gravity values
-are in milligals, as shown. The standard acceleration of gravity is
-980.665 centimeters per second per second; 1 gal is equal to 1
-centimeter per second per second, and 1 milligal is one thousandth
-of a gal. Modified from Case and Joesting (1972, fig. 2). (Fig. 10)</p>
-</div>
-<p>The general shape of the Salt Valley anticline is shown
-also by cross-section <i>B-B&prime;</i> (<a href="#fig10">fig. 10</a>), taken along the northeast-southwest
-<span class="pb" id="Page_32">32</span>
-line <i>B-B&prime;</i> in <a href="#fig9">figure 9</a>, which is based upon
-so-called gravity anomalies over Salt Valley. The lighter
-Paradox Member, having an average density of 2.20, has a
-lower gravitational attraction than the heavier rocks on
-each side, which have an average density of 2.55.</p>
-<p>By this time you are doubtless wondering why prominent
-upfolds of the rocks, such as the Salt Valley anticline
-and associated Cache Valley anticline and the Seven
-Mile-Moab Valley anticline, now underlie relatively deep
-valleys bordered by prominent ridges. The formation of
-these valleys was not simple and involved many steps
-extending over a considerable amount of geologic time, as
-portrayed by Cater (1970, fig. 13; 1972, fig. 4). For a part
-of the story, let us reexamine the cross section (<a href="#fig8">fig. 8</a>);
-the rest of the story will be told in the section on &ldquo;Uplift
-and Erosion.&rdquo;</p>
-<p><a href="#fig8">Figure 8</a> shows that the unnamed upper member of the
-Hermosa Formation and the overlying Cutler and Moenkopi
-Formations are thickest beneath the Courthouse
-syncline but wedge out against the flanks of the anticline.
-Although the Chinle Formation and younger rocks appear
-to extend across the fold, and may have extended across
-this part of the fold, in Colorado all rocks older than the
-Jurassic Morrison wedge out against the flanks of the
-salt anticlines (Cater, 1970, p. 35) and also in the widest
-part of the Salt Valley anticline southwest of the section
-in <a href="#fig8">figure 8</a>. The salt anticlines were uplifted in a series of
-pulses so that some formations either were not deposited
-over the rising structures or were removed by erosion before
-deposition of the next younger unit. By Morrison
-time the supply of salt beneath the synclines seems to
-have become used up; hence, the anticline stopped rising,
-and the Morrison and younger formations were deposited
-across the structures. Thus, in <a href="#fig4">figure 4</a>, the minimum
-thickness of all units older than the Morrison is given
-as zero. <a href="#fig4">Figure 4</a> shows the marine Mancos Shale to be
-the youngest rock unit exposed in the park, but the Mesaverde
-Group of Late Cretaceous age and possibly the
-early Tertiary (<a href="#fig59">fig. 59</a>) Wasatch Formation may have
-been deposited and later removed by erosion.</p>
-<div class="pb" id="Page_33">33</div>
-<h2 class="pcap" id="c9">Uplift And Erosion of The Plateau</h2>
-<div class="img">
-<img src="images/pmg027.jpg" alt="" width="500" height="205" />
-</div>
-<p>Next among the main events leading to the formation
-of landforms in the park was the raising and additional
-buckling and breaking of the Plateau by Earth
-forces partly during the Late Cretaceous but mainly during
-the early Tertiary. After uplift and deformation, the
-Plateau was vigorously attacked by various forces of
-erosion, and the rock materials pried loose or dissolved
-were eventually carted away to the Gulf of California by
-the ancestral Colorado River. Some idea of the enormous
-volume of rock thus removed is apparent when one looks
-down some 2,000 feet to the river from any of the high
-overlooks farther south, such as Dead Horse Point (<a href="../../51048/51048-h/51048-h.htm#fig15">Lohman, 1974, fig. 15</a>).
-Not so apparent, however, is the fact
-that younger Mesozoic and Tertiary rocks more than 1
-mile thick once overlaid this high plateau but have been
-swept away by erosion. In all, the river has carried
-thousands of cubic miles of sediment to the sea and is
-still actively at work on this gigantic earth-moving project.
-In an earlier report (Lohman, 1965, p. 42) I estimated
-that the rate of removal may have been as great as about
-3 cubic miles each century. For a few years the bulk of
-the sediment was dumped into Lake Mead, but now Lake
-Powell is getting much of it. When these and other reservoirs
-ultimately become filled with sediment&mdash;for reservoirs
-and lakes are but temporary things&mdash;the Gulf of
-California will again become the burial ground.</p>
-<p>According to Cater (1970, p. 65-67), who made an intensive
-study of the salt anticlines, collapse of their crests
-seemingly occurred in two stages&mdash;the first stage following
-Late Cretaceous folding; the second following uplift
-<span class="pb" id="Page_34">34</span>
-of the Plateau later in the Tertiary. Solution and removal
-of salt by ground water played the leading role in the
-ultimate collapse.</p>
-<div class="img" id="fig11">
-<img src="images/pmg028.jpg" alt="" width="800" height="472" />
-<p class="pcap">TILTED BLOCK OF ROCKS IN CACHE VALLEY GRABEN, viewed to
-the east toward Cache Valley from point on gravelled side road to
-Wolfe&rsquo;s cabin, about half a mile east of paved road. Steep slope on
-left composed of Jurassic Morrison Formation, hogback on top
-formed by Dakota Sandstone of Late Cretaceous age, and gentle
-slopes to right composed of the Mancos Shale of Late Cretaceous
-age. (Fig. 11)</p>
-</div>
-<p>As shown by Dane (1935, pl. 1, p. 121-126), collapse
-of the Salt Valley and Cache Valley anticlines was accompanied
-by considerable faulting and jointing, particularly
-along their northeast sides; by the upward intrusion
-of two large areas of the Paradox Member of the Hermosa
-Formation, one just northwest of the park and one in the
-middle of Salt Valley south of the campground; and by
-two downdropped masses of rock known to geologists as
-grabens (pronounced gr&auml;b&#477;ns)&mdash;one just northwest of
-the park and one called the Cache Valley graben, which
-extends both east and west from Salt Wash. The Cache
-Valley graben has preserved from erosion the youngest
-rock formations in the park, as shown in <a href="#fig11">figure 11</a>.</p>
-<p>The remarkable jointing of the rocks on the northeast
-limb of the Salt Valley anticline is shown in <a href="#fig12">figure 12</a>.
-All the arches in this section of the park were eroded
-through thin fins of the Slick Rock Member of the Entrada
-<span class="pb" id="Page_35">35</span>
-Sandstone, and some, like Broken Arch, <a href="#fig16">figure 16</a>,
-are capped by the Moab Member.</p>
-<p>Differences in the composition, hardness, arrangement,
-and thickness of the rock layers determine their ability to
-withstand the forces of fracturing and erosion and, hence,
-whether they tend to form cliffs, ledges, fins, or slopes.
-Most of the cliff- or ledge-forming rocks are sandstones
-consisting of sand deposited by wind or water and later
-cemented together by silica (SiO&#8322;), calcium carbonate
-(CaCO&#8323;), or one of the iron oxides (such as Fe&#8322;O&#8323;), but
-some hard, resistant ledges are made of limestone (calcium
-carbonate). The rock column (<a href="#fig4">fig. 4</a>) shows in general
-how these rock formations are sculptured by erosion and
-how they protect underlying layers from more rapid erosion.
-The nearly vertical cliffs along the lower reaches of
-Salt and Courthouse Washes and the Colorado River
-canyon upstream from Moab consist of the well-cemented
-Wingate Sandstone protected above by the even harder
-sandstones of the Kayenta Formation. (See figs. <a href="#fig21">21</a>, <a href="#fig22">22</a>.)
-To borrow from an earlier report of mine (Lohman, 1965, p. 17),
-&ldquo;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&mdash;the Kayenta
-Formation. The Kayenta is much more resistant than the
-Wingate, so even a few feet of the Kayenta * * * protect
-the rock beneath.&rdquo; In some places, as shown in figures <a href="#fig19">19</a>
-and <a href="#fig20">20</a>, the overlying Navajo Sandstone makes up the
-topmost unit of the cliff.</p>
-<div class="pb" id="Page_36">36</div>
-<div class="img" id="fig12">
-<img src="images/pmg029.jpg" alt="" width="800" height="485" />
-<p class="pcap">JOINTED NORTHEAST FLANK OF SALT VALLEY ANTICLINE, viewed
-westward from an airplane. Light-colored wedge in middle background
-is Salt Valley bordered on extreme left by Klondike Bluffs.
-Dark-colored fins and pinnacles on left, of Slick Rock Member of
-the Entrada Sandstone, form Devils Garden. Sharp pinnacle above
-valley is the Dark Angel. (See <a href="#fig57">fig. 57</a>.) White bands of sandstone
-extending to foreground are composed of Moab Member of the
-Entrada. Note vegetation in the joints. Photograph by National Park
-Service. (Fig. 12)</p>
-</div>
-<div class="pb" id="Page_37">37</div>
-<p>Last but far from least among the factors responsible
-for the grandeur of Arches National Park and the Plateau
-in general is the desert climate, which allows one to see
-virtually every foot of the vividly colored naked rocks,
-and which has made possible the creation and preservation
-of such a wide variety of fantastic sculptures. A wetter
-climate would have produced a far different, smoother
-landscape in which most of the rocks and land forms
-would have been hidden by vegetation. On the Plateau
-the vegetation grows mainly on the high mesas and the
-narrow flood plains bordering the rivers, but scanty vegetation
-also occurs on the gentle slopes or flats.</p>
-<p>The combination of layers of sediments of different composition,
-hardness and thickness, the bending and breaking
-of the rocks, and the desert climate, has produced steep
-slopes having many cliffs, ledges, and fins with generally
-sharp to angular edges, rather than the subdued rounded
-forms of more humid regions.</p>
-<h2 class="pcap" id="c10">Origin And Development of The Arches</h2>
-<div class="img">
-<img src="images/pmg030.jpg" alt="" width="500" height="242" />
-</div>
-<p>Among the questions commonly asked by visitors
-are, &ldquo;How do arches form?&rdquo;, &ldquo;Why are some openings
-called windows, others arches?&rdquo;, &ldquo;What is the difference,
-if any, between arches or windows and natural bridges,
-such as those at Natural Bridges National Monument?&rdquo;,
-and &ldquo;How many arches are there in Arches National
-Park?&rdquo; Before taking up the origin and development of
-arches, I shall attempt to explain the differences between
-the three types of natural rock openings named above and
-comment upon the number of arches.</p>
-<div class="pb" id="Page_38">38</div>
-<div class="img" id="fig13">
-<img src="images/map2_lr.jpg" alt="" width="600" height="743" />
-<p class="pcap">INDEX MAP, showing localities where
-most of the photographs were taken.
-Arrows point to distant views. Numbers
-refer to figure numbers. (Fig. 13)<br /><span class="center"><a class="abl" href="images/map2_hr.jpg">High-resolution Map</a></span></p>
-</div>
-<div class="pb" id="Page_40">40</div>
-<p>I believe most geologists and geographers are in general
-agreement with Cleland (1910, p. 314) that &ldquo;a &lsquo;natural
-bridge&rsquo; is a natural stone arch that spans a valley of
-erosion. A &lsquo;natural arch&rsquo; is a similar structure which, however,
-does not span an erosion valley.&rdquo; According to this
-definition, Natural Bridges National Monument includes
-three true bridges, whereas all the larger rock openings in
-Arches National Park with which I am familiar are properly
-termed &ldquo;arches,&rdquo; but some are called windows. If we
-were to distinguish between arches and windows, we might
-say that arches occur at or near the base of a rock wall,
-as do the doors of a house or building, whereas windows
-are found well above ground level. This distinction was
-not followed in naming the rock openings in the park,
-however; for example, Tunnel Arch (<a href="#fig14">fig. 14</a>) is considerably
-higher above the ground than North Window (figs.
-<a href="#fig37">37</a>, <a href="#fig38">38</a>) or South Window (<a href="#fig39">fig. 39</a>).</p>
-<p>As to the number of arches in the park, I might begin
-by saying that there is no universal agreement as to how
-large a rock opening must be to qualify as an arch. The
-pamphlet formerly handed to visitors entering the park
-proclaimed that &ldquo;Nearly 90 arches have been discovered,
-and others are probably hidden away in remote and rugged
-parts of the area,&rdquo; but the average visitor probably
-sees less than a third of this number.</p>
-<p>David May, Assistant Chief of Interpretation and Resource
-Management, Moab office of National Park Service
-(oral commun., Oct. 1973), believes that if only those in
-the park having a minimum dimension of 10 feet in any
-one direction were considered to be arches, the number
-would boil down to about 56 or 57. The most complete
-count of arches and other openings in all of southeastern
-Utah was made by Dale J. Stevens, Professor of Geography
-at Brigham Young University, during the period
-February through April 1973. He considered those with
-openings of 3 feet or larger and found more than 300 in
-southeastern Utah, of which 124 are in Arches National
-Park, although he stated that several areas of the park
-were not intensively searched because of time limitations
-(written commun., July and Sept. 1973). The 124 arches
-<span class="pb" id="Page_41">41</span>
-and openings are distributed among the several named
-areas of the park, as follows: Courthouse Towers, 13;
-Herdina Park, 11; The Windows section, 25; Delicate Arch
-area, 3; Fiery Furnace, 19; Devils Garden, 25; upper Devils
-Garden (northwest of Devils Garden), 14; Eagle Park, 2;
-and Klondike Bluffs, 12.</p>
-<p>Professor Stevens generally used a range finder or a
-steel tape to measure the width and height of the openings
-and the width and thickness of the spans, but estimated
-a few of the dimensions. In the text descriptions of
-arches or captions of figures that follow, I am including
-all or part of these measurements, without further acknowledgment.</p>
-<p>All the arches in the park were formed in the Entrada
-Sandstone, mainly in the Slick Rock Member but partly
-in the Slick Rock and Dewey Bridge Members, and a few
-in the Slick Rock Member occur not far beneath the base
-of the overlying Moab Member. The sandstone of the
-three members is composed mainly of quartz sand cemented
-together by calcium carbonate (CaCO&#8323;), which also
-forms the mineral calcite and the rock known as limestone,
-but the Dewey Bridge Member also contains beds
-of sandy mudstone. Limestone and calcite are soluble in
-acid, even in weak acid such as carbonic acid, HHCO&#8323;,
-also written H&#8322;CO&#8323;, formed by the solution of carbon dioxide
-(CO&#8322;) in water. Ground water, found everywhere in
-rock openings at different depths beneath the land surface,
-contains dissolved carbon dioxide derived from decaying
-organic matter in soil, from the atmosphere, and
-from other sources. Even rainwater and snow contain a
-little carbon dioxide absorbed from the atmosphere&mdash;enough
-to dissolve small amounts of limestone or of calcite
-cement from sandstone. The calcite cement in the Entrada
-and in many other sandstones is unevenly distributed,
-however, so that all the cement is removed first
-from places that contain the least amounts, and, once the
-cement is dissolved away, the loose sand is carried away
-by gravity, wind, or water.</p>
-<p>Both nearly flat but slightly irregular beds of sandstone
-and relatively thin walls or fins of sandstone are prime
-<span class="pb" id="Page_42">42</span>
-targets for this differential erosion. Potholes, as shown
-in <a href="#fig18">figure 18</a><i>A</i>, may be formed in relatively flat beds by the
-dissolving action of repeated accumulations of rainwater
-or snowmelt, even in arid regions like the Plateau.</p>
-<p>Relatively thin walls, or fins as they are called in parts
-of the Plateau including Arches, are targets for the formation
-of alcoves and caves by solution of cement and removal
-of sand by gravity, wind, and water, aided by the
-prying action of frost in joints, bedding planes, or other
-openings. Once a breakthrough of a wall or fin occurs,
-weakened chunks from the ceiling tend to fall, and natural
-arches of various shapes and sizes are produced. Arches
-form the strongest shapes for supporting overlying rock
-loads, as the rock in the arch is compressed toward each
-abutment by the heavy loads. Blocks of compressed rock
-beneath a relatively flat ceiling tend to be dislodged also
-by expansion due to release of pent-up pressure, until a
-strong self-supporting arch is formed. Release of pent-up
-pressure in rock walls may help also in initiating the
-formation of alcoves or caves in cliff faces. Man, including
-the ancient Greeks, Romans, Egyptians, and others, has
-long made use of arches in building bridges, aqueducts,
-temples, cathedrals, and other enduring edifices.</p>
-<p>As vividly shown in <a href="#fig12">figure 12</a>, the Entrada Sandstone
-on the northeast flank of the Salt Valley anticline has
-been broken by Earth forces into thin slabs mostly 10 to
-20 feet thick between nearly parallel joints, but, as will
-be noted in the descriptions of individual arches, some
-rock walls are only 1 or 2 feet thick, whereas others are
-50 feet thick or more. Some weak or thin slabs have
-weathered away, leaving the stronger or thicker ones as
-towering fins, particularly in the Fiery Furnace and Devils
-Garden areas. Jointing on a less spectacular scale also has
-broken the Entrada in areas south of Salt Valley, leaving
-walls or fins of rock.</p>
-<div class="pb" id="Page_43">43</div>
-<div class="img" id="fig14">
-<img src="images/pmg033.jpg" alt="" width="600" height="833" />
-<p class="pcap">TUNNEL ARCH, reached by short trail north of main trail through
-Devils Garden. Opening is 26&frac12; feet wide and 22 feet high; span
-is about 14 feet thick. (Fig. 14)</p>
-</div>
-<div class="pb" id="Page_44">44</div>
-<p>Although all the arches in the park were carved from
-the Entrada Sandstone, slight differences in their mode of
-origin or placement within the Entrada allow them to be
-grouped into three classes: (1) vertical arches formed in
-the Slick Rock Member alone or in the Slick Rock and
-Moab Members, (2) vertical arches formed mainly in the
-Slick Rock Member but partly in, and with the aid of,
-the incompetent underlying Dewey Bridge Member, and
-(3) horizontal arches, or so-called pothole arches, formed
-from the union of a vertical pothole and a horizontal cave.
-Hereinafter, the three members will be referred to alone,
-without reference to the Entrada.</p>
-<div class="img" id="fig15">
-<img src="images/pmg034.jpg" alt="" width="721" height="600" />
-<p class="pcap">&ldquo;BABY ARCH,&rdquo; just southwest of Sheep Rock in Courthouse Towers
-area. For details, see text. (Fig. 15)</p>
-</div>
-<p>Before giving examples of arches in each of the three
-classes, it is appropriate to remark that the arches and
-other erosion forms in the park represent but a fleeting instant
-in geologic time. Many of the pinnacles or piles of
-rock may be the broken remains of former arches, and
-many of the arches we see may be gone tomorrow, next
-year, or a few hundreds of years and, certainly, before
-many thousands of years. On the other hand, many new
-arches will form by the processes described above as the
-geologic clock ticks on.</p>
-<div class="pb" id="Page_45">45</div>
-<div class="img" id="fig16">
-<img src="images/pmg035.jpg" alt="" width="800" height="484" />
-<p class="pcap">BROKEN ARCH, reached by a &frac12;-mile trail leading northward across
-field that separates Fiery Furnace from Devils Garden. White thin-bedded
-unit at top is the Moab Member, which rests upon the
-massive salmon-colored Slick Rock Member. Opening is 59 feet
-wide and 43 feet high. (Fig. 16)</p>
-</div>
-<div class="pb" id="Page_46">46</div>
-<h3 id="c11">Examples of Arches</h3>
-<p>Tunnel Arch (<a href="#fig14">fig. 14</a>) is a good example of an arch
-eroded entirely within the massive Slick Rock Member.
-Just southwest of Sheep Rock (<a href="#fig31">fig. 31</a>) is an unnamed
-opening in the lower part of the Slick Rock Member
-which I call &ldquo;Baby Arch,&rdquo; because it is one of the newest
-ones visible from the park road (<a href="#fig15">fig. 15</a>). It is only 25&frac12;
-feet wide and 14 feet high and penetrates a wall 14 feet
-thick. Note that the breakthrough probably began along
-the prominent recessed bedding plane at the base of the
-arch. Its youthfulness is also indicated by the sharp,
-angular breaks in the ceiling and by the pile of freshly
-fallen rocks. Some visitors have asked park personnel why
-they have not cleared away such debris! Despite its youthfulness,
-the ceiling has already taken on the shape of
-an arch.</p>
-<p>Broken Arch (<a href="#fig16">fig. 16</a>) was formed near the top of the
-Slick Rock Member and is strengthened and protected
-by the more resistant overlying Moab Member, which
-forms the upper half of the span. The crest is only 6 feet
-thick at the thinnest point and is not broken as the name
-seems to imply.</p>
-<p>Double Arch (<a href="#fig17">fig. 17</a>), &ldquo;one&rdquo; of the most beautiful in
-the park, is in The Windows section near the east end of
-the road. The southeast arch, which is 160 feet wide and
-105 feet high, is the second largest in the park, but the
-west arch measures only 60 feet wide and 61 feet high. In
-common with most arches in The Windows section, these
-two arches of the Slick Rock Member rest upon bases of
-the weak, easily eroded Dewey Bridge Member. More
-rapid erosion of the Dewey Bridge undercut the arches
-and hastened their development.</p>
-<div class="pb" id="Page_47">47</div>
-<div class="img" id="fig17">
-<img src="images/pmg036.jpg" alt="" width="600" height="852" />
-<p class="pcap">DOUBLE ARCH, in The Windows section. (Fig. 17)</p>
-</div>
-<div class="pb" id="Page_48">48</div>
-<div class="img" id="fig18">
-<img src="images/pmg037.jpg" alt="" width="800" height="571" />
-<p class="pcap">PROBABLE STEPS IN FORMATION OF POTHOLE ARCH. <i>A</i>, Original
-pothole probably formed in relatively level bed of sandstone, such
-as this one, which is in an older rock unit&mdash;the White Rim Sandstone
-Member of the Cutler Formation, a unit not present in Arches.
-This pothole, which contains 4 feet of water, is in nearby Canyonlands
-National Park (<a href="../../51048/51048-h/51048-h.htm#fig17">Lohman, 1974, fig. 17</a>), just north of the edge
-of the White Rim, about 4&frac12; miles north of the confluence of the
-Green and Colorado Rivers. Photograph by E. N. Hinrichs. <i>B</i>, Pothole
-is being deepened by solution while cliff is receding toward
-pothole by weathering. <i>C</i>, As erosion continues, pothole and cave
-in cliff face are growing deeper. <i>D</i>, Pothole Arch formed by union
-of vertical pothole and horizontal cave. <i>E</i>, Telephoto view of Pothole
-Arch from park road near stop 14. Visible span is 90 feet
-across and 30 feet high. (Fig. 18)</p>
-</div>
-<div class="img">
-<img src="images/pmg038.jpg" alt="Fig. 18 B" width="500" height="210" />
-</div>
-<div class="img">
-<img src="images/pmg039.jpg" alt="Fig. 18 C" width="500" height="200" />
-</div>
-<div class="pb" id="Page_49">49</div>
-<div class="img">
-<img src="images/pmg040.jpg" alt="Fig. 18 D" width="500" height="201" />
-</div>
-<div class="img">
-<img src="images/pmg041.jpg" alt="Fig. 18 E" width="800" height="568" />
-</div>
-<div class="pb" id="Page_50">50</div>
-<p>The cause of the wavy bedding in the Dewey Bridge
-Member, as shown in <a href="#fig17">figure 17</a> but as better shown in the
-frontispiece, is not known for sure but generally is regarded
-to be the result of irregular slumping during or
-just after deposition of the sediments in a body of water,
-caused by the weight of overlying sediments.</p>
-<p>The last example I shall take up is Pothole Arch (<a href="#fig18">fig. 18</a>),
-which differs from all the other examples in that this
-arch is roughly horizontal rather than vertical. Most park
-visitors, including me, were not aware of this interesting
-feature until after publication of the pamphlet &ldquo;The Guide
-to an Auto Tour of Arches National Park,&rdquo; which, as
-previously noted, may be purchased at the Visitor Center.
-Pothole Arch caps a ridge high above the road half a mile
-northwest of Garden of Eden, so only those who happened
-to look up at the right place were aware of its existence.</p>
-<p>A different mode of origin than that given in the caption
-for <a href="#fig18">figure 18</a> is depicted on a poster in the Visitor
-Center, which shows the pothole being formed by a waterfall
-having an apparent flow rate of several cubic feet per
-second. Potholes can be formed in this manner in places
-where sufficient streamflow is available, either continuously
-or following rainstorms, but I believe the process
-depicted in <a href="#fig18">figure 18</a> is a more likely mode of origin for
-Pothole Arch.</p>
-<h2 class="pcap" id="c12">How to See the Park</h2>
-<div class="img">
-<img src="images/pmg042.jpg" alt="" width="500" height="223" />
-</div>
-<p>As aptly stated on a poster in the Visitor Center,
-how to see the park depends in part upon the question
-&ldquo;How long can you stay?&rdquo; Inasmuch as the park entrance
-and Visitor Center are beside a through U.S. Highway
-(163), many motorists first become aware of the park&rsquo;s
-<span class="pb" id="Page_51">51</span>
-existence from the entrance sign, and some take time for
-at least a quick visit, such as a round trip to The Windows
-section, which can be made in an hour or so.</p>
-<p>For those who have or take more time and are able to
-walk at least short distances, a visit of 1 or 2 days is a
-very rewarding experience. Others, particularly avid
-shutterbugs and those with camping gear, profitably
-spend from several days to a week or more and hike all
-or most of the trails.</p>
-<p>Regardless of how long you plan to spend, I urge at
-least a brief stop at the Visitor Center, where excellent
-displays and a narrated slide show help materially in conveying
-just what the park has to offer. At the counter you
-can purchase a copy of &ldquo;The Guide to an Auto Tour of
-Arches National Park,&rdquo; which explains the views from
-each of 25 numbered stops along the park road, as well
-as other reports describing arches or other parks and
-monuments.</p>
-<p>The park is open the year round, but, like most high
-deserts, it gets rather hot in the summer and cold enough
-in the winter for occasional snows and is sometimes closed
-temporarily because of heavy snowfall. The weather generally
-is ideal during the spring and fall. Even though
-summer daytime temperatures may exceed 100&deg;F (37.8&deg;C)
-and slow down hikers, the nights are cool enough for comfortable
-sleeping beneath ample covers.</p>
-<p>Before beginning our trip through the park proper, let
-us consider a beautiful part many people fail to realize
-actually belongs to the park&mdash;the Colorado River canyon
-forming the southeastern boundary.</p>
-<div class="img">
-<img src="images/pmg043.jpg" alt="Petroglyph figure" width="500" height="212" />
-</div>
-<div class="pb" id="Page_52">52</div>
-<h2 class="pcap" id="c13">A Trip Through The Park</h2>
-<div class="img">
-<img src="images/pmg044.jpg" alt="" width="500" height="257" />
-</div>
-<h3 id="c14">Colorado River Canyon</h3>
-<p>The southeastern boundary of the park for
-about 11 miles is the Colorado River, from the bridge on
-which U.S. Highway 163 crosses the river to a point upstream
-about half a mile below the mouth of Salt Wash.
-Illuminated night float trips down part of this reach are
-run during the summer, as noted on <a href="#Page_16">p. 16</a>. Partly paved
-State Highway 128 follows the southeast side of the river
-for about 30 miles to Dewey Bridge, then goes northward
-about 15 miles to Cisco, where it connects with Highway
-I-70.</p>
-<p>The rocks of the Glen Canyon Group form the southernmost
-corner of the park, as shown in <a href="#fig19">figure 19</a>. About 2
-miles northeast of the bridge, we cross the axis of the
-Courthouse syncline (<a href="#fig9">fig. 9</a>), which brings the Navajo
-Sandstone down nearly to river level, as shown in <a href="#fig20">figure 20</a>.
-The underlying Kayenta Formation is largely hidden
-by vegetation and alluvial deposits in this view.</p>
-<div class="pb" id="Page_53">53</div>
-<div class="img" id="fig19">
-<img src="images/pmg045.jpg" alt="" width="825" height="500" />
-<p class="pcap">GLEN CANYON GROUP, forming southernmost point of park, as
-viewed across the Colorado River from State Highway 128 half a
-mile above Moab bridge carrying U.S. Highway 163. Massive sandstone
-forming about the lower third of cliff is the Wingate Sandstone,
-darker thin-bedded sandstones and mudstones forming
-middle section of cliff comprise the Kayenta Formation, upper cliff is
-the lower part of the Navajo Sandstone. Note that the saltcedar (tamarisk),
-which lines both banks of the river, is in full bloom. (Fig. 19)</p>
-</div>
-<div class="pb" id="Page_54">54</div>
-<div class="img" id="fig20">
-<img src="images/pmg046.jpg" alt="" width="882" height="450" />
-<p class="pcap">NAVAJO SANDSTONE CLIFFS, bordering west bank of Colorado River in Courthouse syncline, from State Highway 128
-about 2 miles above the Moab bridge. Note rounded domes at top of cliff. (Fig. 20)</p>
-</div>
-<div class="pb" id="Page_55">55</div>
-<div class="img" id="fig21">
-<img src="images/pmg047.jpg" alt="" width="600" height="713" />
-<p class="pcap">MOUTH OF SALT WASH, viewed across Colorado River from point
-on State Highway 128, 11 miles above Moab bridge. Dark cliffs on
-upper right and left are of Wingate Sandstone capped by thin protective
-cover of resistant sandstone beds of the Kayenta Formation.
-In background Wingate is overlain by entire Kayenta Formation and
-lower part of the Navajo Sandstone. Wingate is underlain to river
-level by weathered slope of the Chinle Formation. Water in Salt
-Wash is largely backwater from the bankfull river; actual flow in
-wash generally is much less but at times reaches flood proportions.
-(Fig. 21)</p>
-</div>
-<p>About 11 miles above the Moab bridge is the mouth of
-Salt Wash (<a href="#fig1">fig. 1</a>), as viewed from State Highway 128.
-(See <a href="#fig21">fig. 21</a>.) Seventeen miles above the bridge (east of
-area shown in <a href="#fig1">fig. 1</a>), we get an excellent view of the
-southeast end of the highly faulted Cache Valley anticline,
-as shown in <a href="#fig22">figure 22</a>. The background shown in the
-<span class="pb" id="Page_56">56</span>
-photograph formerly was the easternmost part of the
-former monument, but when the monument graduated to
-a park on November 16, 1971, this part of Cache Valley
-along with most of Dry Mesa was withdrawn from the
-park and put under the supervision of the Bureau of Land
-Management, also a part of the Department of the
-Interior.</p>
-<div class="img" id="fig22">
-<img src="images/pmg048.jpg" alt="" width="800" height="592" />
-<p class="pcap">SOUTHEAST END OF FAULTED CACHE VALLEY ANTICLINE, viewed
-northwestward across Colorado River from a point on State Highway
-128, 17 miles above Moab bridge. High cliff of Wingate Sandstone
-on left is capped by thin protective layer of the Kayenta
-Formation. About upper third of slope below base of cliff is the
-Chinle Formation, below which is the Moenkopi Formation extending
-to high-water level. Note bent and broken beds on right.
-(Fig. 22)</p>
-</div>
-<p>As noted on <a href="#Page_16">page 16</a>, part of &ldquo;Run, Cougar, Run&rdquo; was
-filmed just upstream from the irrigated field in the foreground
-of <a href="#fig22">figure 22</a>, in a wide part of the valley called
-Professor Valley (<a href="#fig7">fig. 7</a>). This valley and the Richardson
-Amphitheater on the southeast side of the river were
-named after a Professor Richardson who settled in the
-area in the 1880&rsquo;s. The long abandoned townsite of
-Richardson was 1&frac14; miles due east from the point from
-which <a href="#fig22">figure 22</a> was taken.</p>
-<div class="pb" id="Page_57">57</div>
-<h3 id="c15">Headquarters Area</h3>
-<p>The junction of the park road with U.S. Highway 163
-is shown at the lower left of <a href="#fig23">figure 23</a>, and the entrance
-station, Visitor Center, parking lot, and several buildings
-are seen at the lower right. Several residences for park
-personnel and other buildings are shown in <a href="#fig25">figure 25</a>. As
-shown in the lower part of <a href="#fig23">figure 23</a>, the geology at the
-park entrance is rather complex, as the park boundary
-here is partly along the Moab fault and partly along a
-branch fault&mdash;both in the Seven Mile-Moab Valley
-anticline (<a href="#fig7">fig. 7</a>). The Moab fault extends northwestward
-from Moab for more than 30 miles (McKnight, 1940,
-p. 120, 121, pl. 1).</p>
-<p>As shown in <a href="#fig23">figure 23</a>, soon after leaving the checking
-station the park road begins to ascend the first of several
-switchbacks, and cuts first into the Slick Rock Member,
-then the Dewey Bridge Member, and finally the Navajo
-Sandstone the rest of the way to and beyond the top of
-the hill.</p>
-<p>From points a mile or so up the hill may be seen interesting
-features in several directions.<a class="fn" id="fr_5" href="#fn_5">[5]</a> The view to the
-southwest is shown in <a href="#fig23">figure 23</a>, to the west are the Three
-Penguins (<a href="#fig24">fig. 24</a>). A good view of the Moab Valley is
-had by looking southeastward (<a href="#fig25">fig. 25</a>). A well in the
-Navajo Sandstone at the base of the hill supplies water
-to all the residences and to the Visitor Center, where a
-drinking fountain and modern restrooms are available to
-the public. Storage is provided by a steel tank hidden in a
-ravine above the buildings shown in <a href="#fig25">figure 25</a>.</p>
-<p>To the north the wall of Entrada Sandstone is cut by
-a normal fault (<a href="#fig6">fig. 6</a>), as shown in <a href="#fig26">figure 26</a>.</p>
-<div class="pb" id="Page_58">58</div>
-<div class="img" id="fig23">
-<img src="images/pmg049.jpg" alt="" width="800" height="552" />
-<p class="pcap">FAULTED SEVEN MILE-MOAB VALLEY ANTICLINE. Top, View
-toward the southwest from park road about 1 mile above entrance
-station. Bottom, Geologic interpretation of photograph in part after
-McKnight (1940, pl. 1). Moab fault and branch fault (both normal
-faults, <a href="#fig6">fig. 6</a>) unite just beyond ridge of Slick Rock Member. Total
-vertical displacement along both faults is about 2,500 feet. H.F.,
-unnamed upper member of Hermosa Formation; M.F., Moenkopi
-Formation; D, downthrown side of faults; U, upthrown side. Valley
-fill and slope wash of recent (Holocene) age obscure faults and
-underlying rocks. The original sequence of the rocks may be visualized
-by placing the Navajo Sandstone, the upper part of which
-is exposed at the lower right, on top of the Kayenta Formation, the
-lower few feet of which cap and protect the cliffs of Wingate Sandstone
-in the background. The Pacific Northwest (gas) Pipeline
-mentioned on <a href="#Page_15">page 15</a> is buried beneath the slice of the Moenkopi
-Formation between the two faults, which accounts for the disturbed
-appearance of the rock. (Fig. 23)</p>
-</div>
-<div class="img">
-<img src="images/pmg050.jpg" alt="Geologic interpretation of photograph" width="883" height="600" />
-</div>
-<div class="pb" id="Page_59">59</div>
-<div class="img" id="fig24">
-<img src="images/pmg051.jpg" alt="" width="616" height="600" />
-<p class="pcap">THREE PENGUINS, viewed westward from park road about 1 mile
-above entrance station. Penguins are carved in massive Slick Rock
-Member seen resting upon thin-bedded Dewey Bridge Member.
-(Fig. 24)</p>
-</div>
-<div class="pb" id="Page_60">60</div>
-<div class="img" id="fig25">
-<img src="images/pmg052.jpg" alt="" width="900" height="531" />
-<p class="pcap">MOAB VALLEY, viewed southeastward from park road about 1 mile
-above entrance station. Moab fault in about middle of valley, hidden
-beneath recent (Holocene) valley fill and slope wash, separates
-unnamed upper member of Hermosa Formation just above U.S.
-Highway 163 on right from Navajo Sandstone forming hills on left
-and ledges in foreground. Park Service residences at base of hill.
-White patch bordering Colorado River on northwest is tailings pile
-of Atlas Corporation&rsquo;s uranium mill. Moab and Spanish Valley are
-beyond river, and south end of La Sal Mountains forms distant
-skyline. (Fig. 25)</p>
-</div>
-<div class="pb" id="Page_61">61</div>
-<div class="img" id="fig26">
-<img src="images/pmg053.jpg" alt="" width="800" height="583" />
-<p class="pcap">FAULTED WALL OF ENTRADA SANDSTONE, north of park road
-about 1 mile above entrance station. Fault is nearly vertical and
-normal (<a href="#fig6">fig. 6</a>), but fault trace slopes steeply downward to right,
-separating upthrown Slick Rock and Dewey Bridge Members on
-left from downthrown Slick Rock Member on right. Light-colored
-rock in foreground is Navajo Sandstone. Displacement probably
-does not exceed 50 feet. (Fig. 26)</p>
-</div>
-<div class="pb" id="Page_62">62</div>
-<div class="img" id="fig27">
-<img src="images/pmg054.jpg" alt="" width="500" height="850" />
-<p class="pcap">PARK AVENUE, viewed to the north along trail. (Fig. 27)</p>
-</div>
-<div class="pb" id="Page_63">63</div>
-<h3 id="c16">Courthouse Towers Area</h3>
-<p>About 2.3 miles from the entrance station is a turnoff
-and parking area at the south end of the Park Avenue
-trail (stop 2), which is about 1 mile long and ends at
-another parking area 1.7 miles farther north. An interesting
-hike is best made from south to north in a downhill
-direction, and hikers generally meet the cars of relatives
-or friends awaiting them at the northern parking area. The
-trail begins in a canyon cut in the soft Dewey Bridge
-Member and walled by high fins of the Slick Rock Member
-(<a href="#fig27">fig. 27</a>), but farther north the canyon is floored by the
-bare Navajo Sandstone. The avenue was named from the
-resemblance of the east wall to a row of tall buildings.
-Atop the west wall, just to the left of the view in
-<a href="#fig27">figure 27</a>, are two balanced rocks (<a href="#fig28">fig. 28</a>). The one on the left,
-which resembles somewhat the head of an Egyptian queen,
-is offset to the right along a bedding plane, and this offset
-may have been caused by an earthquake.</p>
-<p>As we progress toward Courthouse Towers proper, lofty
-fins and monoliths lie mostly on our left, and to the right
-are fine distant views of the La Sal Mountains (stop 4).
-A general view of the Courthouse Towers is shown in
-<a href="#fig29">figure 29</a>, and closeups of two of the named rock sculptures&mdash;the
-Three Gossips and Sheep Rock&mdash;are shown in
-figures <a href="#fig30">30</a> and <a href="#fig31">31</a>. Just beyond Sheep Rock, which some
-think resembles the Sphinx, we see &ldquo;Baby Arch,&rdquo; shown
-in <a href="#fig15">figure 15</a>.</p>
-<p>Five miles from the entrance station, the road crosses
-Courthouse Wash on a modern bridge (stop 6)&mdash;a
-distinct improvement over the two tracks in the sand we
-used in 1946. The Courthouse syncline, named after the
-wash, extends northwestward through here. (See figs. <a href="#fig8">8</a>,
-<a href="#fig9">9</a>, <a href="#fig20">20</a>.) About a mile west of the bridge, Professor Stevens
-found another pothole arch. A mile and a half north of the
-bridge is stop 7, where attention is called in the booklet
-to the vast area of &ldquo;petrified dunes&rdquo; east of the road,
-which are simply dunelike exposures of the crossbedded
-Navajo Sandstone formed originally by the cementation
-of a vast area of sand dunes. My view of these was taken
-about 1 mile beyond the stop (<a href="#fig32">fig. 32</a>).</p>
-<div class="pb" id="Page_64">64</div>
-<div class="img" id="fig28">
-<img src="images/pmg055.jpg" alt="" width="600" height="845" />
-<p class="pcap">BALANCED ROCKS ON SOUTH WALL OF PARK AVENUE, at south end of trail. (Fig. 28)</p>
-</div>
-<div class="pb" id="Page_65">65</div>
-<div class="img" id="fig29">
-<img src="images/pmg056.jpg" alt="" width="600" height="679" />
-<p class="pcap">COURTHOUSE TOWERS, viewed to the northwest from point on
-park road about three-fourths of a mile northeast of the south end
-of Park Avenue trail. Sandstone towers are Slick Rock Member
-resting on Dewey Bridge Member, which also forms foreground.
-Three Gossips at upper left, Sheep Rock just beyond. The Organ
-and Tower of Babel are on right. (Fig. 29)</p>
-</div>
-<div class="pb" id="Page_66">66</div>
-<div class="img" id="fig30">
-<img src="images/pmg057.jpg" alt="" width="547" height="801" />
-<p class="pcap">THE THREE GOSSIPS, shown at upper left of <a href="#fig29">figure 29</a>. (Fig. 30)</p>
-</div>
-<div class="img" id="fig31">
-<img src="images/pmg058.jpg" alt="" width="480" height="800" />
-<p class="pcap">SHEEP ROCK, shown on center-left skyline in <a href="#fig29">figure 29</a>. (Fig. 31)</p>
-</div>
-<p>West of the road between the petrified dunes and The
-Windows section, the Entrada Sandstone, particularly the
-Dewey Bridge Member, has been weathered into grotesque
-spires and pinnacles resembling the so-called &ldquo;hoodoos and
-goblins&rdquo; in Goblin Valley State Park, just north of Hanksville,
-Utah. Typical examples of &ldquo;hoodoos and goblins&rdquo; are
-shown in <a href="#fig33">figure 33</a> (near stop 8). It seems reasonable to
-assume that some of these spires are the skeletal remains
-of former arch abutments. From here may be seen North
-and South Windows and Turret Arch on the skyline to
-the northeast (figs. <a href="#fig37">37</a>-<a href="#fig40">40</a>).</p>
-<div class="pb" id="Page_67">67</div>
-<div class="img" id="fig32">
-<img src="images/pmg059.jpg" alt="" width="908" height="550" />
-<p class="pcap">PETRIFIED SAND DUNES, looking northeast from park road 2.7
-miles north of Courthouse Wash. The Navajo Sandstone was once
-a huge sandpile of dunes laid down by winds during an arid interval,
-so it is interesting to note that the irregularly weathered sandstone
-once again resembles a pile of crossbedded dunes. See also
-<a href="#fig35">figure 35</a>. (Fig. 32)</p>
-</div>
-<div class="pb" id="Page_68">68</div>
-<div class="img" id="fig33">
-<img src="images/pmg060.jpg" alt="" width="800" height="595" />
-<p class="pcap">&ldquo;HOODOOS AND GOBLINS,&rdquo; weathered from Dewey Bridge Member,
-viewed northwest from park road about 2&frac12; miles north of Courthouse
-Wash. (Fig. 33)</p>
-</div>
-<h3 id="c17">The Windows Section</h3>
-<p>The Windows section, one of the most beautiful parts
-of the park, once was the only readily accessible part of
-the former monument and is still the only collection of
-arches seen by many visitors who either do not have or do
-not take time to travel farther north. All the arches and
-erosion forms are on or near a high crest called Elephant
-Butte (Dane, 1935, p. 126, 127), which separates Salt
-Valley from the Courthouse syncline. The ridge also marks
-the south edge of several minor anticlines and synclines
-termed by Dane the &ldquo;Elephant Butte folds.&rdquo;</p>
-<div class="pb" id="Page_69">69</div>
-<div class="img" id="fig34">
-<img src="images/pmg061.jpg" alt="" width="800" height="524" />
-<p class="pcap">EYE OF THE WHALE, one of several arches in Herdina Park, just
-south of jeep trail about 2 miles northwest of Balanced Rock. Cut
-in Slick Rock Member. Front opening is 60 feet wide and 27 feet
-high, but back opening is only 35 feet wide and 11 feet high. Photograph
-by Professor Dale J. Stevens, Brigham Young University.
-(Fig. 34)</p>
-</div>
-<p>Guarding the approach to The Windows section is
-Balanced Rock (stop 9). As shown in the frontispiece, it
-is accompanied on the right by another balanced rock and
-a third one may be seen in the distance. The original route
-to The Windows section, pioneered by Goulding, passed
-just north of Balanced Rock. Traces of the old road between
-here and the Garden of Eden parking area are still
-visible but no longer used. To the west, however, a part
-of the old road is the starting point of a jeep trail leading
-northwestward through Herdina Park to a point near
-Klondike Bluffs, where it joins the dirt road in Salt Valley
-(<a href="#fig1">fig. 1</a>). Visitors having four-wheel-drive vehicles may
-wish to drive at least as far as Eye of The Whale (<a href="#fig34">fig. 34</a>),
-<span class="pb" id="Page_70">70</span>
-which is about 2 miles northwest of Balanced Rock. There
-are several picnic tables at the beginning of this jeep trail,
-but no water.</p>
-<div class="img" id="fig35">
-<img src="images/pmg062.jpg" alt="" width="734" height="600" />
-<p class="pcap">INTRICATE CROSSBEDS IN NAVAJO SANDSTONE, on north side
-of road between Garden of Eden and Cove of Caves. Red crest is
-basal part of Dewey Bridge Member. (Fig. 35)</p>
-</div>
-<p>Just beyond Balanced Rock, a branch paved road turns
-eastward 2&frac12; miles to the main parking lots in The
-Windows section. Between the Garden of Eden (stop 13)
-and Cove of Caves are spectacular exposures of the
-Navajo Sandstone showing the crossbedding typical of the
-original dunes (<a href="#fig35">fig. 35</a>). Just east of the crossbedded
-Navajo Sandstone, shown in <a href="#fig35">figure 35</a>, we pass Cove Arch
-and Cove of Caves (stop 10) on the north side of the
-road (<a href="#fig36">fig. 36</a>).</p>
-<p>Just around the curve east of Cove of Caves is the first
-of two parking lots (stop 11) forming a one-way loop at
-the end of this branch of the road. From the loop may be
-seen the greatest concentration of readily accessible arches
-<span class="pb" id="Page_71">71</span>
-in the park, all of which are roofed by the Slick Rock
-Member and floored by the Dewey Bridge Member. Let
-us take the short paved trail from the upper lot to the
-southeast, where we come first to North Window (<a href="#fig37">fig. 37</a>).
-If we walk through this arch and climb the rock beyond
-(<a href="#fig37">fig. 37</a> caption), we see one of the best views in the park
-(<a href="#fig38">fig. 38</a>). A short walk south of North Window brings us
-to South Window (<a href="#fig39">fig. 39</a>). The other side of this arch
-may be reached either by walking around the nearby
-southeast end of the fin or by walking through North
-Window. A short walk to the southwest brings us to
-Turret Arch&mdash;the one seen through North Window in
-<a href="#fig38">figure 38</a>. <a href="#fig40">Figure 40</a> was taken from the southwest side
-of Turret Arch, viewed northeastward toward South
-Window, one corner of which appears at the left. Both
-North and South Windows may be seen in one photograph
-taken from points near Turret Arch.</p>
-<div class="img" id="fig36">
-<img src="images/pmg063.jpg" alt="" width="836" height="600" />
-<p class="pcap">COVE ARCH AND COVE OF CAVES, on north side of road just west
-of Double Arch and Parade of Elephants. Arch at left and three of
-the caves on right are roofed by Slick Rock Member and floored by
-Dewey Bridge Member. Arch is 48&frac12; feet wide and 34 feet high.
-In time the caves will eat through the 30-foot-thick fin and become
-arches. Note sharp contact between Dewey Bridge Member and
-Navajo Sandstone. (Fig. 36)</p>
-</div>
-<div class="pb" id="Page_72">72</div>
-<div class="img" id="fig37">
-<img src="images/pmg064.jpg" alt="" width="762" height="600" />
-<p class="pcap">NORTH WINDOW, viewed to the northeast. Large rock seemingly
-partly blocking left end of arch actually is the southeast end of a
-fin some 50 feet or more beyond the arch, from
-which <a href="#fig38">figure 38</a> was taken. Arch is 93 feet wide and 51 feet high. (Fig. 37)</p>
-</div>
-<p>From the lower parking lot (stop 12), a short walk by
-paved trail takes us to spectacular Double Arch, shown in
-<a href="#fig17">figure 17</a>. This arch is visible from the parking lot but is
-best seen and photographed from at or near the end of the
-trail. Looking westward from near the trail&rsquo;s end, we see
-the Parade of Elephants, shown in <a href="#fig41">figure 41</a>. This feature
-is described on pages 16 and 17 of &ldquo;The Guide to an Auto
-Tour of Arches National Park&rdquo; as &ldquo;whimsical stone
-statuary resembling a circus pachyderm parade. With tail
-in trunk, the elephants rumble toward you along a sandstone
-roadway.&rdquo;</p>
-<p>Ribbon Arch, on the north side of Elephant Butte, is one
-of the most delicate ones in the park (<a href="#fig1">fig. 1</a>). Although it
-is 50 feet wide and 55 feet high, the rock span is only
-1&frac12; feet wide and 1 foot thick.</p>
-<div class="pb" id="Page_73">73</div>
-<p>On the way back to the intersection with the main park
-road, we pass stop 14, from which may be seen Pothole
-Arch (<a href="#fig18">fig. 18</a>). One and one-half miles north of the intersection
-with the main road is the Panorama Point parking
-area (stop 15), which affords fine distant views of Salt
-and Cache Valleys and points beyond. A roadside exhibit
-portrays the gradual development of the Salt Valley anticline,
-which supplements my description on pages <a href="#Page_27">27</a>-<a href="#Page_32">32</a>.
-A parking space a short distance farther down the hill
-(stop 16) provides good distant views of the Fiery Furnace.
-I tried several telephoto shots from this viewpoint,
-but preferred my closeup views, such as the one shown in
-<a href="#fig44">figure 44</a>.</p>
-<div class="img" id="fig38">
-<img src="images/pmg065.jpg" alt="" width="710" height="600" />
-<p class="pcap">LOOKING SOUTHWESTWARD THROUGH NORTH WINDOW, from
-fin shown beyond left side of North Window in <a href="#fig37">figure 37</a>. Turret
-Arch (<a href="#fig40">fig. 40</a>) is seen at right middle ground, south rim of Moab
-Valley to left of arch, Colorado River canyon forms left skyline.
-(Fig. 38)</p>
-</div>
-<div class="pb" id="Page_74">74</div>
-<div class="img" id="fig39">
-<img src="images/pmg066.jpg" alt="" width="600" height="612" />
-<p class="pcap">SOUTH WINDOW, viewed toward northeast. Arch is 105 feet wide
-and 66 feet high. See text. (Fig. 39)</p>
-</div>
-<h3 id="c18">Delicate Arch Area</h3>
-<p>Two and a half miles northeast of the road intersection
-near Balanced Rock, a gravelled side road leads northeastward
-to several points of considerable interest. The
-photograph in <a href="#fig11">figure 11</a> was taken from this side road
-about half a mile northeast of the intersection. About 2
-miles to the northeast, just beyond Salt Valley Wash, is
-a parking area (stop 17) at the beginning of the trail past
-Wolfe&rsquo;s Bar-DX Ranch (<a href="#fig3">fig. 3</a>) to famed Delicate Arch,
-which is featured on the front cover. Although the trail
-to the arch is only 1&frac12; miles long, it crosses several hills
-at the outset, then climbs 500 feet, mostly on bare Entrada
-Sandstone, so is considered quite strenuous, particularly
-<span class="pb" id="Page_75">75</span>
-in hot weather. The Park Service advises hikers to carry
-water. The Walt Disney crew, cameras, gear, cougars, and
-all climbed this trail in the hottest part of the summer of
-1971 (see <a href="#Page_16">p. 16</a>), while my wife and I were working in
-the vicinity. Visitors who do not wish to make the hike
-may get a distant view of Delicate Arch by driving to a
-parking area (stop 18) 1.3 miles farther east.</p>
-<div class="img" id="fig40">
-<img src="images/pmg067.jpg" alt="" width="600" height="612" />
-<p class="pcap">TURRET ARCH, viewed northeast toward South Window, part of
-which is visible on left. Small opening on right is visible also in
-<a href="#fig38">figure 38</a>. Largest arch is 39 feet wide and 64 feet high; smaller
-one is 12 feet wide and 13 feet high. A still smaller one, not visible
-in the photograph, is 8 feet wide and only 4&frac12; feet high. (Fig. 40)</p>
-</div>
-<div class="pb" id="Page_76">76</div>
-<div class="img" id="fig41">
-<img src="images/pmg068.jpg" alt="" width="900" height="522" />
-<p class="pcap">PARADE OF ELEPHANTS, viewed west from end of trail to Double
-Arch. Two elephants are on right, one on left. (Fig. 41)</p>
-</div>
-<div class="pb" id="Page_77">77</div>
-<p>After leaving Wolfe&rsquo;s Ranch, the trail to Delicate Arch
-crosses Salt Wash on a suspension foot bridge (<a href="#fig42">fig. 42</a>).
-Just beyond the bridge, a short walk to the left (north)
-leads to the Ute petroglyphs shown in the lower photograph
-of <a href="#fig2">figure 2</a>. The most difficult part of the trail, on
-bare sandstone, is marked by cairns of stones placed at
-sufficient intervals to keep hikers from losing the barely
-visible trail. When the summit finally is reached and the
-last corner rounded, one suddenly sees perhaps the most
-sublime view in the park&mdash;famed Delicate Arch, framing
-part of the La Sal Mountains beyond (<a href="#fig43">fig. 43</a>). This
-graceful arch and mighty Landscape Arch (<a href="#fig53">fig. 53</a>) were
-considered to be in serious jeopardy during the era of
-sonic booms, but hopefully this danger now is past. (See
-p. <a href="#Page_16">16</a>-<a href="#Page_17">17</a>.)</p>
-<p>It may be of interest to shutterbugs that professional
-photographer Hal Rumel lugged an 8- &times; 10-inch camera
-plus a heavy tripod and accessories up the steep trail to
-get the excellent photograph of Delicate Arch shown in
-<a href="#fig43">figure 43</a>. The late afternoon sun intensified the red somewhat,
-but my shots made earlier in the day using both
-4- &times; 5-inch and 35-mm equipment resulted in unwanted
-shadows, even though the salmon color of the Slick Rock
-Member was more nearly normal.</p>
-<p>After leaving the junction with the side road, the main
-park road traverses slices of vertical strata squeezed between
-faults along the north side of Salt Valley, then
-gradually climbs out of the valley for about 2 miles to a
-parking area (stop 19), from which good views are had of
-the southeast end of Salt Valley and of the grabens in the
-west end of Cache Valley. (See <a href="#fig11">fig. 11</a>.)</p>
-<div class="img">
-<img src="images/pmg069.jpg" alt="Petroglyph figure" width="400" height="140" />
-</div>
-<div class="pb" id="Page_78">78</div>
-<div class="img" id="fig42">
-<img src="images/pmg070.jpg" alt="" width="693" height="600" />
-<p class="pcap">SUSPENSION FOOT BRIDGE ACROSS SALT WASH, in front of
-Wolfe&rsquo;s cabin at beginning of Delicate Arch trail. (Fig. 42)</p>
-</div>
-<div class="img" id="fig43">
-<img src="images/pmg071.jpg" alt="" width="655" height="600" />
-<p class="pcap">DELICATE ARCH, from end of trail 1&frac12; miles above Wolfe&rsquo;s Ranch.
-The opening is 33 feet wide and 45 feet high. The left abutment
-is only 5 feet wide at the narrowest point. The arch is carved near
-the top of the Slick Rock Member, and the top of the span, 19
-feet thick, is capped by a few feet of the more resistant Moab
-Member, as is Broken Arch (<a href="#fig16">fig. 16</a>). Photograph by Hal Rumel,
-Salt Lake City. (Fig. 43)</p>
-</div>
-<div class="pb" id="Page_79">79</div>
-<h3 id="c19">Fiery Furnace</h3>
-<p>About half a mile farther uphill is a parking area for
-viewing the southeastern part of the Fiery Furnace (stop
-20), a vast array of towering fins and pinnacles of the
-reddish Slick Rock Member separated by narrow slots,
-vaguely resembling flames shooting skyward. The view of
-the Fiery Furnace in <a href="#fig44">figure 44</a> was taken about 1 mile
-farther up the hill. It is not difficult to get lost among this
-myriad of fins and narrow slots, so ranger-guided tours
-are conducted during the summer.</p>
-<p>About 1 mile farther northwest is a parking area (stop
-23) from which a short walk to the north end of Fiery
-Furnace leads to a narrow slot between high fins (<a href="#fig45">fig. 45</a>),
-along which a short sandy trail leads to a recess along the
-southwest wall containing Sand Dune Arch (<a href="#fig46">fig. 46</a>). This
-hidden arch receives sunshine only near the middle of the
-day and is a delightful, shady place to rest.</p>
-<p>From the entrance to the slot leading to Sand Dune
-Arch, a trail goes half a mile north across an open field to
-Broken Arch, shown in <a href="#fig16">figure 16</a>. This field, which separates
-the Fiery Furnace and Devils Garden areas, is seen
-from the air in <a href="#fig12">figure 12</a>.</p>
-<div class="img">
-<img src="images/pmg072.jpg" alt="Petroglyph figure" width="300" height="281" />
-</div>
-<div class="pb" id="Page_80">80</div>
-<div class="img" id="fig44">
-<img src="images/pmg073.jpg" alt="" width="937" height="500" />
-<p class="pcap">FIERY FURNACE, viewed northwest along park road about 1 mile northwest from stop 20. Fins and spires are of the jointed
-Slick Rock Member (<a href="#fig12">fig. 12</a>), but the top of the Dewey Bridge Member is seen to the right of the curve in the road. (Fig. 44)</p>
-</div>
-<div class="pb" id="Page_81">81</div>
-<div class="img" id="fig45">
-<img src="images/pmg074.jpg" alt="" width="600" height="849" />
-<p class="pcap">TRAIL TO SAND DUNE ARCH, looking northwest away from arch,
-between towering fins of Slick Rock Member, at northwest end
-of Fiery Furnace. Southeast end of Devils Garden in distance.
-(Fig. 45)</p>
-</div>
-<div class="pb" id="Page_82">82</div>
-<div class="img" id="fig46">
-<img src="images/pmg075.jpg" alt="" width="760" height="600" />
-<p class="pcap">SAND DUNE ARCH, in recess along southwest wall of narrow slot
-shown in <a href="#fig45">figure 45</a>. Slick Rock Member. (Fig. 46)</p>
-</div>
-<h3 id="c20">Salt Valley and Klondike Bluffs</h3>
-<p>Before proceeding to the end of the paved road, let us
-take an unimproved side road, which turns south about a
-third of a mile beyond the last stop, in order to see more
-of Salt Valley and to visit Klondike Bluffs in the northwestern
-part of the park. After descending 2.3 miles of
-winding road we reach the normally dry bed of Salt Valley
-Wash, and turn abruptly to the northwest. For the next
-three-fourths of a mile the &ldquo;road&rdquo; is simply two tracks in
-the loose, sandy bed of the wash, which obviously should
-not be travelled when flooded or when there is even a
-hint of rain. In dry weather, however, this road may be
-travelled by ordinary passenger car. This stretch of the
-wash cuts through an intruded block of the Paradox
-Member of the Hermosa Formation consisting mainly of
-gray and brown gypsum, the common salt having been
-<span class="pb" id="Page_83">83</span>
-dissolved out by ground water. Such an intrusive block of
-salt-bearing rock is known to geologists as a diapir&mdash;not
-to be confused with the garment (diaper) worn by
-infants.</p>
-<p>From here on the road traverses a rather uninteresting
-stretch of valley north of Salt Valley Wash. Eleven miles
-from the starting point, the road reaches an intersection
-from which a side road leads southwestward three-fourths
-of a mile to a parking area at the foot of Klondike Bluffs,
-which form the south side of Salt Valley. From here, one
-may make a strenuous hike over a primitive trail about
-1&frac12; miles long to beautiful Tower Arch (<a href="#fig47">fig. 47</a>).</p>
-<p>The valley road continues northwestward from the intersection
-to and beyond the northwest end of the park and
-connects with roads to Crescent Junction, Thompson, and
-the Yellow Cat mining district, north of the park (<a href="#Page_14">p. 14</a>).</p>
-<p>Let us return to the paved road and continue our tour
-of the park.</p>
-<h3 id="c21">Devils Garden</h3>
-<p>Turning left (northwest) at the intersection with the
-paved park road, we enter Devils Garden&mdash;another large
-maze of towering red fins separated by narrow slots, which
-resembles the Fiery Furnace. After a third of a mile, we
-reach stop 24 and walk 100 feet or more to the north for a
-good view of Skyline Arch (<a href="#fig48">fig. 48</a>). This arch is very
-appropriately named, as it forms the skyline viewed either
-from the road on the south or from the campground on
-the north, from points south of the amphitheater. Less
-well known is the fact that Skyline Arch is clearly visible
-to the naked eye or through binoculars from stretches
-of Highway I-70 (or old U.S. Highways 6 and 50) about
-11 miles to the north. Most arches and other erosion forms
-do not change appearance much from day to day or year
-to year, but some, like &ldquo;Baby Arch&rdquo; (<a href="#fig15">fig. 15</a>), show evidence
-of relatively recent origin. In November 1940
-(Abbey, 1971, p. 42) Skyline Arch suddenly doubled in size
-by the fall of a large rock that occupied what is now the
-northwest half of the arch. Photographs taken before and
-after this event appear on pages 24 and 25 of the road
-guide and also in the museum at the Visitor Center.</p>
-<div class="pb" id="Page_84">84</div>
-<div class="img" id="fig47">
-<img src="images/pmg076.jpg" alt="" width="600" height="732" />
-<p class="pcap">TOWER ARCH, on Klondike Bluffs, viewed eastward. Arch is in
-Slick Rock Member but tower on left, after which arch was named,
-is capped by a protective layer of the resistant Moab Member.
-Opening is 88 feet wide and 43 feet high. Photograph by Robert D.
-Miller. (Fig. 47)</p>
-</div>
-<div class="pb" id="Page_85">85</div>
-<div class="img" id="fig48">
-<img src="images/pmg077.jpg" alt="" width="897" height="550" />
-<p class="pcap">SKYLINE ARCH, viewed north from point about 100 feet north of
-stop 24, in Slick Rock Member. Although fins are vertical, note
-that the strata seem to dip about 15&deg; to the right, although the
-actual dip is to the northeast. (See <a href="#fig50">fig. 50</a>.) (Fig. 48)</p>
-</div>
-<div class="pb" id="Page_86">86</div>
-<p>Another half mile brings us to a one-way (to right) loop
-at the end of the park road. Just beyond the beginning
-of the loop is a parking lot and very attractive picnic
-area containing several picnic tables shaded by pi&ntilde;on
-pines at the foot of a towering red fin of the Slick Rock
-Member. Just north of this picnic ground, a paved side
-road leads eastward into a truly beautiful, well-equipped
-campground comprising both back-in and drive-through
-campsites for trailers, campers, or tents; three pairs of
-modern restrooms, hydrants, and drinking fountains; and
-an amphitheater, where illustrated campfire talks are
-given nightly during the summer. The east end of the
-campground is shown in <a href="#fig49">figure 49</a>.</p>
-<div class="img" id="fig49">
-<img src="images/pmg078.jpg" alt="" width="807" height="600" />
-<p class="pcap">CAMPGROUND IN DEVILS GARDEN, viewed northwestward across
-turn-around at southeastern end. (Fig. 49)</p>
-</div>
-<p>Devils Garden in general and the campground in particular
-are on the crest of a ridge separating Salt Valley to
-the southwest from the Sagers Wash syncline to the northeast,
-which lies north of Yellow Cat Flat and north of the
-<span class="pb" id="Page_87">87</span>
-area shown in <a href="#fig1">figure 1</a>. From the higher parts of the campground
-striking views are to be had toward the north and
-northeast, particularly late in the afternoon, as shown in
-<a href="#fig50">figure 50</a>.</p>
-<div class="img" id="fig50">
-<img src="images/pmg079.jpg" alt="" width="768" height="600" />
-<p class="pcap">VIEW NORTH FROM CAMPGROUND, in late afternoon. Reddish
-Slick Rock Member capped by light-colored Moab Member are
-seen dipping northeastward toward Sagers Wash syncline. Book
-Cliffs, north of Thompson, are 16 miles north on left skyline.
-(Fig. 50)</p>
-</div>
-<p>In about the middle of the one-way loop at the end of
-the park road is a well that supplies water to the campground
-from early in the spring until the return of freezing
-weather late in the fall. The well, which was drilled in
-1962 to a depth of 900 feet, obtains a small amount of
-water from the Wingate Sandstone. No water was found in
-the overlying Navajo and Entrada Sandstones because of
-the pronounced dip of the rocks toward the northeast,
-which allows any water in these rocks to drain northeastward
-(Ted Arnow, written commun., 1963). Water from
-this well is pumped to a steel tank in a high part of the
-<span class="pb" id="Page_88">88</span>
-campground, whence it flows by gravity to the three sets
-of restrooms.</p>
-<div class="img" id="fig51">
-<img src="images/pmg080.jpg" alt="" width="600" height="738" />
-<p class="pcap">SOUTHEASTERN PART OF DEVILS GARDEN TRAIL, viewed northwestward.
-Narrow slot between fins of Slick Rock Member indicates
-local spacing of joints. (Fig. 51)</p>
-</div>
-<p>At the northwest end of the one-way loop is a large
-parking area for use by people hiking the Devils Garden
-trail. This trail leads to seven of the most interesting
-arches in the park, all of which are in the Slick Rock
-Member, and there are many more farther to the northwest.
-The approximate distances to the seven arches are
-given in the paragraphs that follow. The trail is paved
-for about 1 mile as far as Landscape Arch (<a href="#fig53">fig. 53</a>), but
-from there to Double O Arch (<a href="#fig56">fig. 56</a>) the trail is primitive,
-and the Park Service recommends rubber soles as
-part of the trail is on bare sandstone. For these reasons,
-many visitors hike only as far as Landscape Arch.</p>
-<div class="pb" id="Page_89">89</div>
-<div class="img" id="fig52">
-<img src="images/pmg081.jpg" alt="" width="600" height="825" />
-<p class="pcap">PINE TREE ARCH, viewed northeastward. Opening is 46 feet wide
-and 48 feet high. Fin is 30 feet thick. (Fig. 52)</p>
-</div>
-<div class="pb" id="Page_90">90</div>
-<p>Much of the trail, particularly the first part, lies in a
-narrow slot between fins of the Slick Rock Member, as
-shown in <a href="#fig51">figure 51</a>. After about half a mile, a side trail
-to the north leads to a <span class="ss">Y</span>, the right-hand fork of which
-goes to Tunnel Arch (<a href="#fig14">fig. 14</a>). The left-hand fork leads to
-Pine Tree Arch, obviously named for the pi&ntilde;on pine
-framed by this arch (<a href="#fig52">fig. 52</a>).</p>
-<p>At the end of the improved part of the trail, we reach
-Landscape Arch (<a href="#fig53">fig. 53</a>), claimed by the Park Service to
-be the longest known natural arch in the world. According
-to Ouellette (1958) it is 291 feet long and 118 feet high,
-but Professor Stevens&rsquo; measurements indicate it to be 287
-feet long and 106 feet high. At its thinnest point on the
-right, the span is only 11 feet wide and 11 feet thick. In
-1958 three young men made what was claimed to be the
-second known ascent of Landscape Arch, using ropes and
-other climbing gear, after which they walked across (Ouellette,
-1958). This crossing was made with the permission
-of a park ranger, but such permission is no longer given,
-for the safety of both the arch and of would-be climbers.</p>
-<p>Wall Arch is about a quarter of a mile beyond the end
-of the improved part of the trail, and another three-fourths
-mile brings us to Navajo Arch (<a href="#fig54">fig. 54</a>) and Partition Arch
-(<a href="#fig55">fig. 55</a>). A distant view of Partition Arch may be had
-just before reaching Landscape Arch. Part of the remaining
-trail to Double O Arch (<a href="#fig56">fig. 56</a>) is on the top of a low
-sandstone fin, in part between somewhat higher fins and
-in part above lower slots.</p>
-<div class="pb" id="Page_91">91</div>
-<div class="img" id="fig53">
-<img src="images/pmg082.jpg" alt="" width="800" height="493" />
-<p class="pcap">LANDSCAPE ARCH, viewed southwestward from near end of improved
-part of Devils Garden trail. Note that ground beneath arch
-is covered by slope wash and near the middle with what appears
-to be a small landslide. Slick Rock Member here is more nearly
-buff than salmon colored, because of a smaller content of iron
-oxide. Fresh breaks and angular blocks of stone at right abutment
-indicate relatively recent rock falls. See text for size. (Fig. 53)</p>
-</div>
-<div class="pb" id="Page_92">92</div>
-<div class="img" id="fig54">
-<img src="images/pmg083.jpg" alt="" width="742" height="600" />
-<p class="pcap">NAVAJO ARCH, viewed northeastward from a branch of Devils Garden
-trail. One of few arches having a flat soil-covered floor. Opening
-is 40&frac12; feet wide. Photograph by National Park Service. (Fig. 54)</p>
-</div>
-<p>Beautiful Double O Arch (<a href="#fig56">fig. 56</a>) is at the end of the
-Devils Garden trail about 2&frac12; miles northwest of the trailhead.
-About half a mile northwest of the trail&rsquo;s end is a
-prominent landmark called Dark Angel (<a href="#fig57">fig. 57</a>), which is
-visible in <a href="#fig12">figure 12</a> and from the unimproved road in Salt
-Valley.</p>
-<div class="pb" id="Page_93">93</div>
-<div class="img" id="fig55">
-<img src="images/pmg084.jpg" alt="" width="600" height="615" />
-<p class="pcap">PARTITION ARCH, viewed southwestward from near Devils Garden
-trail. Arch frames part of south wall of Salt Valley and, on skyline,
-mesas south of Moab Valley. Opening is 27&frac12; feet wide and 26 feet
-high. A smaller opening to the right measures 8&frac12; feet wide and
-8 feet high. Photograph by Dawn E. Reed. (Fig. 55)</p>
-</div>
-<div class="img" id="fig56">
-<img src="images/pmg085.jpg" alt="" width="853" height="600" />
-<p class="pcap">DOUBLE O ARCH, viewed about north from northwest end of Devils
-Garden trail. Large opening is 71 feet wide and 45 feet high; small
-one at lower left is 21 feet wide and 11 feet high. Span of large
-opening is 11 feet wide and 6 feet thick. Arch frames a part of the
-Book Cliffs about 14 miles to the north. Photograph by Hildegard
-Hamilton, Flagstaff, Ariz. (Fig. 56)</p>
-</div>
-<div class="pb" id="Page_94">94</div>
-<div class="img" id="fig57">
-<img src="images/pmg086.jpg" alt="" width="594" height="999" />
-<p class="pcap">DARK ANGEL, a shaft of the Slick Rock Member that is an erosional
-remnant of a once high, narrow fin. About one-half mile
-northwest of Double O Arch. Photograph by National Park Service.
-(Fig. 57)</p>
-</div>
-<div class="pb" id="Page_95">95</div>
-<div class="img" id="fig58">
-<img src="images/pmg087.jpg" alt="" width="692" height="600" />
-<p class="pcap">&ldquo;INDIAN-HEAD ARCH,&rdquo; in upper Devils Garden. Arch and most of
-head are in Slick Rock Member, top of head is basal part of Moab
-Member. Opening is 4 feet wide and 4&frac12; feet high. Photograph by
-Professor Dale J. Stevens, Brigham Young University. (Fig. 58)</p>
-</div>
-<div class="pb" id="Page_96">96</div>
-<div class="img" id="fig59">
-<img src="images/pmg088.jpg" alt="" width="1000" height="816" />
-<p class="pcap">GEOLOGIC TIME SPIRAL, showing the sequence, names,
-and ages of the geologic eras, 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 Precambrian Era
-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 Paleozoic Era. (Fig. 59)</p>
-</div>
-<div class="box">
-<p class="center ccap">GEOLOGIC TIME
-<br />The Age of the Earth</p>
-<p class="pcap">The Earth is very old&mdash;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&rsquo;s crust. The rock layers
-themselves&mdash;like pages in a long and complicated history&mdash;record
-the surface-shaping events of the past, and buried within them are
-traces of life&mdash;the plants and animals that evolved from organic
-structures that existed perhaps 3 billion years ago.</p>
-<p class="pcap">Also contained in rocks once molten are radioactive elements
-whose isotopes provide Earth scientists with an atomic clock. Within
-these rocks, &ldquo;parent&rdquo; isotopes decay at a predictable rate to form
-&ldquo;daughter&rdquo; isotopes. By determining the relative amounts of parent
-and daughter isotopes, the age of these rocks can be calculated.</p>
-<p class="pcap">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!</p>
-</div>
-<div class="pb" id="Page_98">98</div>
-<p>Professor Stevens found 14 arches in what he called
-upper Devils Garden, northwest of Double O Arch, and
-two arches in the northwesternmost extension of the park
-known as Eagle Park (<a href="#fig1">fig. 1</a>). One of the unnamed arches
-in upper Devils Garden is shown in <a href="#fig58">figure 58</a>. I am tentatively
-calling it &ldquo;Indian-Head Arch,&rdquo; because of the rather
-obvious resemblance.</p>
-<p>This ends our journey through Arches National Park,
-but there remains for consideration a summary of the
-principal geologic events leading to the formation of this
-beautiful part of the Colorado Plateau and a brief comparison
-with the geology of other national parks and
-monuments on the Plateau.</p>
-<h2 class="pcap" id="c22">Summary of Geologic History</h2>
-<div class="img">
-<img src="images/pmg089.jpg" alt="" width="500" height="234" />
-</div>
-<p>Having finished our geologic trip through Arches
-National Park, let us see how the arches and other features
-fit into the bigger scheme of things&mdash;the geologic age
-and events of the Earth as a whole, as depicted in
-<a href="#fig59">figure 59</a>. As shown in <a href="#fig4">figure 4</a>, the rock strata still preserved
-in the park range in age from Pennsylvanian to Cretaceous,
-or from about 300 million to 100 million years old&mdash;a
-span of about 200 million years. This seems an incredibly
-long time, until one notes that the earth is some 4.5 billion
-years old, and that our rock pile is but 1/23 or 4&frac12; percent
-of the age of the Earth as a whole. Thus, in <a href="#fig59">figure 59</a>, the
-rocks exposed in the park occupy only about the left half
-of the top whorl of the spiral.</p>
-<p>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
-<span class="pb" id="Page_99">99</span>
-by erosion, and if we include these the span is increased
-to about 250 million years, or nearly a full whorl of
-the spiral.</p>
-<p>Deep tests for oil and gas tell us that much older rocks
-underlie the area, and we have seen that some of these
-played a part in shaping the park we see today. In addition
-to the Precambrian igneous and metamorphic rocks,
-there is about 2,000 feet of Paleozoic sedimentary rocks
-older than the Pennsylvanian Paradox Member of the
-Hermosa Formation, most of which was laid down in ancient
-seas. This includes strata of Cambrian, Ordovician,
-Devonian, Mississippian, and Pennsylvanian ages (<a href="#fig59">fig. 59</a>).
-There are some gaps in the rock record caused by
-temporary emergence of the land above sea level and
-erosion of the land surface before the land again subsided
-below sea level so that deposition could resume. Silurian
-rocks are absent, presumably because, here, the Silurian
-Period was dominated by erosion rather than deposition.</p>
-<p>While Pennsylvanian and Permian rocks were being
-laid down in and southwest of the park, a large area to
-the northeast, called by geologists the Uncompahgre Highland
-(because it occupied the same general area as part
-of the present Uncompahgre Plateau), rose slowly above
-sea level. Whatever Paleozoic rocks were on this rising
-land plus part of the underlying Precambrian rocks were
-eroded and carried by streams into deep basins to the
-northeast and southwest. Thus, while some marine or near-shore
-deposits were being laid down in and south of the
-park, thousands of feet of red beds were being laid down
-by streams between the park and what is now the Uncompahgre
-Plateau. During part of Middle Pennsylvanian
-time, a large area, including the park, known as the Paradox
-basin, was alternately connected to or cut off from the
-sea, so that the water was evaporated during cutoff periods
-and replenished during periods when connection with
-the sea resumed. In these huge evaporation basins were
-deposited the salt and gypsum plus some potash salts and
-shale that now make up the Paradox Member of the
-Hermosa Formation.</p>
-<p>Arches National Park contains four northwesterly trending
-<span class="pb" id="Page_100">100</span>
-major folds&mdash;the Salt Valley and Cache Valley salt
-anticlines, the Courthouse syncline, and the faulted Moab-Seven
-Mile anticline, which forms the southwestern border.
-How these folds were formed was explained on pages <a href="#Page_27">27</a>-<a href="#Page_32">32</a>.
-The history of their growth, however, was a long one
-that began about 300 million years ago in the Pennsylvanian
-and ended about 50 million years ago in the early
-Tertiary. The growth of these folds occurred in two stages.
-The first stage, which involved the development of the salt
-cores of the anticlines, ended in the Jurassic with the
-beginning of Morrison time; the second stage, which involved
-additional folding that intensified the magnitude
-and shape of existing folds, occurred in the early Tertiary
-and was followed later by collapse of the salt anticlines.
-The formation and collapse of the Salt Valley and Cache
-Valley anticlines was accompanied by pronounced jointing
-(<a href="#fig12">fig. 12</a>), which allowed differential erosion to produce the
-tall fins in which the arches were formed.</p>
-<p>The old Uncompahgre Highland continued to shed
-debris into the bordering basins until Triassic time, when
-it began to be covered by a veneer of red sandstone and
-siltstone of the Chinle Formation (Lohman, 1965). The
-area remained above sea level during the Triassic Period
-and most, if not all, of the Jurassic Period, although the
-Jurassic Carmel Formation was laid down in a sea that
-lay just to the west.</p>
-<p>Late in the Cretaceous Period a large part of Central
-and Southeastern United States, including the eastern
-half of Utah, sank beneath the sea and received thousands
-of feet of mud, silt, and some sand that later compacted
-into the Mancos Shale. This formation, as well as all
-younger and some older strata, has long since been eroded
-from most of the park area, but a little of the Mancos is
-preserved in the Cache Valley graben (<a href="#fig11">fig. 11</a>), and the
-entire Mancos Shale and younger rocks are present in
-adjacent areas, such as the Book Cliffs north of Green
-River, Crescent Junction, and Cisco (figs. <a href="#fig7">7</a>, <a href="#fig50">50</a>, <a href="#fig56">56</a>).</p>
-<p>The land rose above the sea at about the close of the
-Cretaceous and has remained above ever since, although
-inland basins and lakes received sediment during parts
-<span class="pb" id="Page_101">101</span>
-of the Tertiary Period. Compressive forces in the Earth&rsquo;s
-crust produced some gentle folding of the strata at the
-close of the Cretaceous, but more pronounced folding and
-some faulting occurred during the Eocene Epoch, when
-most of the Rocky Mountains took form. During the Miocene
-Epoch igneous rock welled up into older rocks to
-form the cores of the nearby La Sal, Abajo, and Henry
-Mountains. Additional uplift and some folding occurred
-in the Pliocene and Pleistocene Epochs.</p>
-<p>Much of the course of the Colorado River was established
-during the Miocene Epoch, with some additional
-adjustments in the late Pliocene and early Pleistocene
-Epochs (Hunt, C. B., 1969, p. 67). Erosion during much
-of the Tertiary Period and all of the Quaternary Period
-plus some sagging and breaking of the crest of the anticlines,
-brought on by solution and lateral squeezing of salt
-beds beneath the Moab-Seven Mile, Salt Valley, and
-Cache Valley anticlines, combined to produce the landscape
-as we now see it.</p>
-<p>The Precambrian rocks beneath the area are about 1.5
-billion years old; so an enormous span of time is represented
-by the rocks and events in and beneath Canyonlands
-National Park.</p>
-<p>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 &ldquo;Geologic Time
-Spiral&rdquo; (<a href="#fig59">fig. 59</a>).</p>
-<p>Dinosaur N.M., with exposed rocks ranging in age from
-Precambrian to Cretaceous, covers the greatest time span
-(nearly 2 billion years), but has one unit&mdash;the Jurassic
-Morrison Formation&mdash;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
-<span class="pb" id="Page_102">102</span>
-units in supporting roles. Grand Canyon N.P. and N.M.
-are next, with rocks ranging in age from Precambrian
-through Permian (excluding the Quaternary lava flows
-in the N.M.), but here there 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.</p>
-<p>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 Precambrian age with only a veneer of
-much younger rocks, obviously has but one star in its
-cast. Colorado N.M. contains rocks ranging from Precambrian
-to Cretaceous&mdash;equal to Dinosaur in this respect,
-but Colorado is unique in that all the 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.</p>
-<p>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&mdash;a Permian member younger than
-the Cedar Mesa&mdash;plays the starring role.</p>
-<p>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&mdash;the
-Triassic Chinle Formation, in which are found many
-petrified logs and stumps of ancient trees. The Triassic-Jurassic
-Glen Canyon Group (<a href="#fig19">fig. 19</a>), which includes the
-<span class="pb" id="Page_103">103</span>
-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.</p>
-<p>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, despite the fact that the latter
-is the type locality of the entire Glen Canyon Group. 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.</p>
-<p>As we journey upward in the time spiral (<a href="#fig59">fig. 59</a>), 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 &ldquo;hoodoos and goblins&rdquo; in Goblin Valley State Park,
-north of Hanksville, Utah.</p>
-<p>Moving ever upward in the spiral, we come to the Cretaceous&mdash;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 same ancient people who once dwelt
-in Arches N.P. and nearby areas.</p>
-<p>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 volcanoes and
-some older volcanic features at Sunset Crater N.M., near
-Flagstaff, Ariz.</p>
-<p>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
-<span class="pb" id="Page_104">104</span>
-to the footlights. Don&rsquo;t let them down&mdash;visit and enjoy
-the national parks and monuments of the Plateau, for
-they probably are the greatest collection of scenic wonderlands
-in the world.</p>
-<h2 class="pcap" id="c23">Additional Reading</h2>
-<div class="img">
-<img src="images/pmg090.jpg" alt="" width="500" height="192" />
-</div>
-<p>Many reports covering various aspects of the
-area have been cited in the text by author and year, and
-these plus a few additional ones are listed in &ldquo;Selected
-References.&rdquo; A few works of general or special interest
-should be mentioned, however.</p>
-<p>Between 1926 and 1929 the entire area now included
-in the park was mapped geologically in classic reports by
-Dane (1935) and by McKnight (1940). These men and
-their field assistants mapped the area by use of the plane-table
-and telescopic alidade without benefit of modern
-topographic maps or aerial photographs, except for topographic
-maps of the narrow stretch along the Colorado
-River mapped under the direction of Herron (1917). Only
-small sections could be reached by automobile, so nearly
-all the area was traversed using horses and mules or by
-hiking. This work plus mapping done in nearby areas to
-the south and to the north (Stokes, 1952) during the
-uranium boom of the mid-fifties was used by Williams
-(1964) in compiling a geologic map of the Moab quadrangle
-at a scale of 1:250,000.</p>
-<p>Several early reports on the Colorado River and its
-potential utilization contain a wealth of information and
-many fine photographs, including two by La Rue (1916,
-1925) and one by Follansbee (1929).</p>
-<p>You may be interested in brief accounts of the geology
-of other national parks and monuments, or other areas of
-special interest, such as the reports on the Uinta Mountains
-by Hansen (1969), Mount Rainier by Crandell
-<span class="pb" id="Page_105">105</span>
-(1969), Yellowstone National Park by Keefer (1971),
-and ones by me on
-Colorado National Monument (Lohman, 1965) and Canyonlands National Park (<a href="../../51048/51048-h/51048-h.htm">1974</a>).</p>
-<p>For those who wish to learn more about the science
-of geology, I suggest the textbook by Gilluly, Waters, and
-Woodford (1968).</p>
-<h2 id="c24"><br /><span class="small">Acknowledgments</span></h2>
-<p>I am greatly indebted to Bates Wilson, former
-Superintendent, and to former Assistant Superintendent
-Joe Carithers, for their splendid cooperation in supplying
-data and information; to Chuck Budge, former Chief
-Ranger; Dave May, Assistant Chief of Interpretation and
-Resource Management; Joe Miller, former Maintenance
-Engineer; Bob Kerr, new Superintendent; Maxine Newell,
-Park Historian and member of the staff at Arches National
-Park; Jerry Banta, former Park Ranger at Arches;
-and Carl Mikesell, Park Ranger at Arches, for their many
-favors.</p>
-<p>I am grateful to several colleagues and friends for the
-loan of photographs, for geologic help and data, and for
-reviewing this report. I am also deeply grateful to my
-wife, Ruth, for accompanying me on all the fieldwork
-and for her help and encouragement.</p>
-<h2 id="c25"><br /><span class="small">Selected References</span></h2>
-<dl class="undent"><dt>Abbey, Edward, 1971, Desert solitaire, a season in the wilderness: New York, Ballantine Books, 303 p.</dt>
-<dt>Baker, A. A., 1933, Geology and oil possibilities of the Moab district, Grand and San Juan Counties, Utah: U.S. Geol. Survey Bull. 841, 95 p.</dt>
-<dt>Baker, Pearl, 1971, The Wild Bunch at Robbers Roost: New York, Aberlard-Schuman, 224 p.</dt>
-<dt>Beckwith, Frank, 1934, A group of petroglyphs near Moab, Utah: Santa Fe, N. Mex., El Palacio, v. 36, p. 177-178.</dt>
-<dt>Breed, Jack, 1947, Utah&rsquo;s arches of stone: Natl. Geog. Mag., p. 173-192, August.</dt>
-<dt>Case, J. E., and Joesting, H. R., 1972, Regional geophysical investigations in the central Colorado Plateau: U.S. Geol. Survey Prof. Paper 736, 34 p.</dt>
-<dt class="pb" id="Page_106">106</dt>
-<dt>Cater, F. W., 1970, Geology of the salt anticline region in southwestern Colorado: U.S. Geol. Survey Prof. Paper 637, 80 p.</dt>
-<dt>&mdash;&mdash; 1972, Salt anticlines within the Paradox Basin, <i>in</i> Geologic atlas of the Rocky Mountain region, United States of America: Denver, Colo., Rocky Mtn. Assoc. of Geologists, p. 137, 138, fig. 4.</dt>
-<dt>Cleland, H. F., 1910, North American natural bridges, with a discussion of their origins: Geol. Soc. America Bull., v. 21, p. 313-338.</dt>
-<dt>Crandell, D. R., 1969, The geologic story of Mt. Rainier: U.S. Geol. Survey Bull. 1292, 43 p.</dt>
-<dt>Dane, C. H., 1935, Geology of the Salt Valley anticline and adjacent areas, Grand County, Utah: U.S. Geol. Survey Bull. 863, 184 p.</dt>
-<dt>Dellenbaugh, F. S., 1902, The romance of the Colorado River: New York, G. P. Putnam&rsquo;s Sons, 399 p. [reprinted 1962 by Rio Grande Press, Chicago, Ill.]</dt>
-<dt>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.</dt>
-<dt>Follansbee, Robert, 1929, Upper Colorado River and its utilization: U.S. Geol. Survey Water-Supply Paper 617, 394 p.</dt>
-<dt>Gilluly, James, Waters, A. C., and Woodford, A. O., 1968, Principles of geology [3d ed.]: San Francisco, W. R. Freeman &amp; Co., 685 p.</dt>
-<dt>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.</dt>
-<dt>Herron, W. R., 1917, Profile surveys in the Colorado River Basin in Wyoming, Utah, Colorado, and New Mexico: U.S. Geol. Survey Water-Supply Paper 396, 6 p., 43 pls.</dt>
-<dt>Hite, R. J., 1972, Pennsylvanian rocks, <i>in</i> Geologic atlas of the Rocky Mountain region, United States of America: Denver, Colo., Rocky Mtn. Assoc. of Geologists, p. 133-137.</dt>
-<dt>Hite, R. J., and Lohman, S. W., 1973, Geologic appraisal of Paradox basin salt deposits for waste emplacement: U.S. Geol. Survey open-file report, 75 p.</dt>
-<dt>Hunt, Alice, 1956, Archeology of southeastern Utah, <i>in</i> Geology and economic deposits of east-central Utah: Salt Lake City, Intermountain Assoc. of Petroleum Geologists, 7th Ann. Field Conf., p. 13-18.</dt>
-<dt>Hunt, C. B., 1956, Cenozoic geology of the Colorado Plateau: U.S. Geol. Survey Prof. Paper 279, 99 p.</dt>
-<dt>&mdash;&mdash; 1969, Geologic history of the Colorado River, <i>in</i> The Colorado River region and John Wesley Powell: U.S. Geol. Survey Prof. Paper 669, p. I-IV, 59-130.</dt>
-<dt class="pb" id="Page_107">107</dt>
-<dt>Jennings, J. D., 1970, Canyonlands-Aborigines: Naturalist, v. 21, Summer, Special Issue no. 2, p. 10-15.</dt>
-<dt>Joesting, H. R., Case, J. E., and Plouff, Donald, 1966, Regional geophysical investigations of the Moab-Needles area, Utah: U.S. Geol. Survey Prof. Paper 516-C, 21 p.</dt>
-<dt>Keefer, W. R., 1971, The geologic story of Yellowstone National Park, illustrated by John R. Stacy: U.S. Geol. Survey Bull. 1347, 92 p. [1972].</dt>
-<dt>Lansford, Henry, 1972, Boatman in the desert, a passenger-carrying sternwheeler in canyon country: &ldquo;Empire&rdquo; [magazine of the Denver Post], Nov. 5, p. 18, 19.</dt>
-<dt>La Rue, E. C., 1916, Colorado River and its utilization: U.S. Geol. Survey Water-Supply Paper 395, 231 p.</dt>
-<dt>&mdash;&mdash; 1925, Water power and flood control of Colorado River below Green River, Utah, with a foreword by Hubert Work, Secretary of the Interior, p. 1-100. [Appendix A, A report on water supply, by E. C. La Rue and G. F. Holbrook, p. 101-123; and Appendix B, A geologic report on the inner gorge of the Grand Canyon of Colorado River, by R. C. Moore, p. 125-171]: U.S. Geol. Survey Water-Supply Paper 556, 176 p.</dt>
-<dt>Lohman, S. W., 1965, The geologic story of Colorado National Monument [with graphics by John R. Stacy]: Fruita, Colo., Colorado and Black Canyon Natural History Assoc., 56 p.</dt>
-<dt>&mdash;&mdash; 1974, <a href="../../51048/51048-h/51048-h.htm">The geologic story of Canyonlands National Park</a>, with graphics by John R. Stacy: U.S. Geol. Survey Bull. 1327, 126 p.</dt>
-<dt>McKnight, E. T., 1940, Geology of area between Green and Colorado Rivers, Grand and San Juan Counties, Utah: U.S. Geol. Survey Bull. 908, 147 p.</dt>
-<dt>Ouellette, C. M., 1958, Over the top of Landscape Arch: Desert Mag., p. 13-16, March.</dt>
-<dt>Pierson, Lloyd, 1960, Arches National Monument, <i>in</i> Geology of the Paradox basin fold and fault belt: Durango, Colo., Four Corners Geol. Soc. Guidebook, 3d Ann. Field Conf., p. 17-21.</dt>
-<dt>Schaafsma, Polly, 1971, Rock art of Utah: Cambridge, Mass., Harvard Univ., Papers of the Peabody Museum of Archaeology and Ethnology, v. 65, 169 p.</dt>
-<dt>Stacy, J. R., 1962, Shortcut method for the preparation of shaded-relief illustrations, <i>in</i> Short papers in geology, hydrology, and topography 1962: U.S. Geol. Survey Prof. Paper 450-D, p. D164-D165.</dt>
-<dt>Stokes, W. L., 1952, Uranium-vanadium deposits of the Thompsons area, Grand County, Utah, with emphasis on the origin of carnotite ores: Utah Geol. and Mineralogical Survey Bull. 46, 51 p., December.</dt>
-<dt class="pb" id="Page_108">108</dt>
-<dt>&mdash;&mdash; 1970, Canyonlands&mdash;Geology: Naturalist, v. 21, Summer, Special Issue no. 2, p. 3-9.</dt>
-<dt>Walters, H. H., 1956, Pacific Northwest Pipeline&mdash;The scenic inch, <i>in</i> Geology and economic deposits of east-central Utah: Salt Lake City, Intermountain Assoc. of Petroleum Geologists, p. 169-170.</dt>
-<dt>Williams, P. L., 1964, Geology, structure, and uranium deposits of the Moab quadrangle, Colorado and Utah: U.S. Geol. Survey Misc. Geol. Inv. Map I-360.</dt>
-<dt>Wilson, B. E., 1956, Arches National Monument, <i>in</i> Geology and economic deposits of east-central Utah: Salt Lake City, Intermountain Assoc. of Petroleum Geologists, 7th Ann. Field Conf., p. 50-51.</dt>
-<dt>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.</dt></dl>
-<div class="img">
-<img src="images/pmg091.jpg" alt="Petroglyph figure" width="500" height="429" />
-</div>
-<h2><br /><span class="small">Footnotes</span></h2>
-<div class="fnblock"><div class="fndef"><a class="fn"  id="fn_1" href="#fr_1">[1]</a>Mrs. Tanner, of Phoenix, Ariz., is the author of an earlier history of Moab
-(her hometown). She has completed a revision entitled, &ldquo;The Far Country&mdash;A
-Regional History of Moab and La Sal, Utah,&rdquo; which will be serialized in
-the Moab Times-Independent, after which it will be published.
-</div><div class="fndef"><a class="fn"  id="fn_2" href="#fr_2">[2]</a>For the benefit of visitors from countries in which the metric system is
-used, the following conversion factors may be helpful: 1 inch = 2.54 centimeters,
-1 foot = 0.305 meter, 1 mile = 1.609 kilometers, 1 U.S. gallon = 0.00379
-cubic meter.
-</div><div class="fndef"><a class="fn"  id="fn_3" href="#fr_3">[3]</a>Barrier Creek flows through Horseshoe Canyon in the detached unit of
-Canyonlands National Park. The canyon walls are adorned by striking pictographs
-(<a href="../../51048/51048-h/51048-h.htm#fig2">Lohman, 1974, fig. 2</a>). &ldquo;Barrier Canyon style&rdquo; is named after the
-pictographs found in Horseshoe Canyon.
-</div><div class="fndef"><a class="fn"  id="fn_4" href="#fr_4">[4]</a>Plastic-relief maps are no longer available from the U.S. Army Map Service
-but may be obtained from the T. N. Hubbard Scientific Co., Box 105,
-Northbrook, Ill. 60062. A topographic map at a scale of 1:250,000 of the
-Moab quadrangle and similar maps at a scale of 1:62,500 for the Thompson,
-Cisco, Moab, and Castle Valley quadrangles are available from the U.S. Geological
-Survey, Denver Distribution Section, Federal Center, Denver, Colo.
-80225, from the Canyonlands Natural History Association at Moab, and from
-privately owned shops where maps are sold. Most of the park is covered by the
-Thompson and Moab quadrangles. The southern part of the park is shown also
-on the Moab 4 NW, Moab 4 NE, and Mt. Waas 3 NW quadrangles at a scale
-of 1:24,000. A special topographic map of Arches National Park at a scale of
-1:50,000 is in preparation by the U.S. Geological Survey. These maps also
-may be obtained from the above-listed sources.
-</div><div class="fndef"><a class="fn"  id="fn_5" href="#fr_5">[5]</a>This is numbered stop 1 in the booklet referred to earlier &ldquo;The Guide to
-an Auto Tour of Arches National Park,&rdquo; and corresponds to the numeral one
-on a small sign at the roadside parking place. Some of the other numbers are
-given in the pages that follow.
-</div>
-</div>
-<div class="pb" id="Page_109">109</div>
-<h2 id="c26"><br /><span class="small">Index</span></h2>
-<p class="center"><a href="#index_A" class="ab">A</a> <a href="#index_B" class="ab">B</a> <a href="#index_C" class="ab">C</a> <a href="#index_D" class="ab">D</a> <a href="#index_E" class="ab">E</a> <a href="#index_F" class="ab">F</a> <a href="#index_G" class="ab">G</a> <a href="#index_H" class="ab">H</a> <a href="#index_I" class="ab">I</a> <a href="#index_J" class="ab">J</a> <a href="#index_K" class="ab">K</a> <a href="#index_L" class="ab">L</a> <a href="#index_M" class="ab">M</a> <a href="#index_N" class="ab">N</a> <a href="#index_O" class="ab">O</a> <a href="#index_P" class="ab">P</a> <span class="ab">Q</span> <a href="#index_R" class="ab">R</a> <a href="#index_S" class="ab">S</a> <a href="#index_T" class="ab">T</a> <a href="#index_U" class="ab">U</a> <a href="#index_V" class="ab">V</a> <a href="#index_W" class="ab">W</a> <span class="ab">X</span> <a href="#index_Y" class="ab">Y</a> <a href="#index_Z" class="ab">Z</a></p>
-<p class="center small">[Italic page numbers indicate major references]</p>
-<dl class="index">
-<dt class="center" id="index_A"><b>A</b></dt>
-<dt class="jr">Page</dt>
-<dt>Abajo Mountains<span class="jr"> <a href="#Page_101">101</a></span></dt>
-<dd>artifacts<span class="jr"> <a href="#Page_9">9</a></span></dd>
-<dt>Abbey, Edward<span class="jr"> <a href="#Page_3">3</a></span></dt>
-<dt>Aborigines, occupation of area<span class="jr"> <a href="#Page_9">9</a></span></dt>
-<dt>Acknowledgments<span class="jr"> <i><a href="#Page_105">105</a></i></span></dt>
-<dt>Anasazi people, petroglyphs<span class="jr"> <a href="#Page_10">10</a></span></dt>
-<dt>Anasazi ruins<span class="jr"> <a href="#Page_9">9</a>, <a href="#Page_103">103</a></span></dt>
-<dt>Ancestral Colorado River<span class="jr"> <a href="#Page_33">33</a></span></dt>
-<dt>Anomalies, gravity, Salt Valley<span class="jr"> <a href="#Page_32">32</a></span></dt>
-<dt>Anticlines, salt<span class="jr"> <a href="#Page_31">31</a></span></dt>
-<dt>Arches, broken remains<span class="jr"> <a href="#Page_44">44</a></span></dt>
-<dd>examples<span class="jr"> <i><a href="#Page_46">46</a></i></span></dd>
-<dd>former abutments<span class="jr"> <a href="#Page_68">68</a></span></dd>
-<dd>horizontal<span class="jr"> <a href="#Page_44">44</a></span></dd>
-<dd>how they are formed<span class="jr"> <a href="#Page_42">42</a></span></dd>
-<dd>natural, defined<span class="jr"> <i><a href="#Page_40">40</a></i></span></dd>
-<dd>number in the park<span class="jr"> <a href="#Page_40">40</a>, <i><a href="#Page_41">41</a></i></span></dd>
-<dd>origin and development<span class="jr"> <a href="#Page_37">37</a></span></dd>
-<dd>pothole<span class="jr"> <a href="#Page_44">44</a></span></dd>
-<dd>vertical<span class="jr"> <a href="#Page_42">42</a>, <a href="#Page_44">44</a></span></dd>
-<dt>Artifacts, La Sal and Abajo Mountains<span class="jr"> <a href="#Page_9">9</a></span></dt>
-<dt>Aspinall, Wayne, Representative<span class="jr"> <a href="#Page_8">8</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_B"><b>B</b></dt>
-<dt>&ldquo;Baby Arch&rdquo;<span class="jr"> <a href="#Page_46">46</a>, <a href="#Page_63">63</a>, <a href="#Page_83">83</a></span></dt>
-<dt>Balanced Rock<span class="jr"> <a href="#Page_69">69</a>, <a href="#Page_70">70</a>, <a href="#Page_74">74</a></span></dt>
-<dt>Banta, Jerry<span class="jr"> <a href="#Page_105">105</a></span></dt>
-<dt>Bar-DX Ranch<span class="jr"> <a href="#Page_12">12</a>, <a href="#Page_13">13</a>, <a href="#Page_14">14</a></span></dt>
-<dt>&ldquo;Barrier Canyon style&rdquo;<span class="jr"> <a href="#Page_10">10</a></span></dt>
-<dt>Bedding, wavy, Dewey Bridge Member<span class="jr"> <a href="#Page_46">46</a></span></dt>
-<dt>Beeson, Stib<span class="jr"> <a href="#Page_13">13</a></span></dt>
-<dt>Beginning of a monument<span class="jr"> <i><a href="#Page_1">1</a></i></span></dt>
-<dt>Bending of rocks<span class="jr"> <i><a href="#Page_24">24</a></i></span></dt>
-<dt>Bennett, Wallace F., Senator<span class="jr"> <a href="#Page_8">8</a></span></dt>
-<dt>Beroni, Pete<span class="jr"> <a href="#Page_14">14</a>, <a href="#Page_15">15</a></span></dt>
-<dt>Black Canyon of the Gunnison National Monument<span class="jr"> <a href="#Page_102">102</a></span></dt>
-<dt>Book Cliffs<span class="jr"> <a href="#Page_100">100</a></span></dt>
-<dt>Breaking of rocks<span class="jr"> <i><a href="#Page_24">24</a></i></span></dt>
-<dt>Bridge, natural, defined<span class="jr"> <i><a href="#Page_40">40</a></i></span></dt>
-<dt>Broken Arch<span class="jr"> <a href="#Page_46">46</a>, <a href="#Page_79">79</a></span></dt>
-<dt>Brown-Stanton expedition, exploration<span class="jr"> <a href="#Page_15">15</a></span></dt>
-<dt>Bryce Canyon National Park<span class="jr"> <a href="#Page_103">103</a></span></dt>
-<dt>Budge, Chuck<span class="jr"> <a href="#Page_105">105</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_C"><b>C</b></dt>
-<dt>Cache Valley<span class="jr"> <a href="#Page_56">56</a>, <a href="#Page_73">73</a>, <a href="#Page_77">77</a></span></dt>
-<dt>Cache Valley anticline<span class="jr"> <a href="#Page_25">25</a>, <a href="#Page_32">32</a>, <a href="#Page_34">34</a>, <a href="#Page_55">55</a>, <a href="#Page_100">100</a>, <a href="#Page_101">101</a></span></dt>
-<dt>Cache Valley graben<span class="jr"> <a href="#Page_34">34</a>, <a href="#Page_100">100</a></span></dt>
-<dt>Campground<span class="jr"> <a href="#Page_86">86</a></span></dt>
-<dd>water supply<span class="jr"> <a href="#Page_87">87</a></span></dd>
-<dt>Cane Creek anticline<span class="jr"> <a href="#Page_24">24</a></span></dt>
-<dt>Canyon de Chelly National Monument<span class="jr"> <a href="#Page_102">102</a></span></dt>
-<dt><i>Canyon King</i><span class="jr"> <a href="#Page_8">8</a></span></dt>
-<dt>Canyon Lands Section, Colorado Plateau<span class="jr"> <a href="#Page_9">9</a>, <a href="#Page_22">22</a></span></dt>
-<dt>Canyonlands National Park<span class="jr"> <a href="#Page_3">3</a>, <a href="#Page_9">9</a>, <a href="#Page_15">15</a>, <a href="#Page_102">102</a></span></dt>
-<dt>Canyonlands Natural History Association<span class="jr"> <a href="#Page_8">8</a></span></dt>
-<dt>Capitol Reef National Park<span class="jr"> <a href="#Page_103">103</a></span></dt>
-<dt>Carithers, Joe<span class="jr"> <a href="#Page_105">105</a></span></dt>
-<dt>Carmel Formation<span class="jr"> <a href="#Page_100">100</a></span></dt>
-<dt>Cassidy, Butch<span class="jr"> <a href="#Page_12">12</a></span></dt>
-<dt>Caves, Entrada Sandstone<span class="jr"> <a href="#Page_9">9</a></span></dt>
-<dt>Cedar Breaks National Monument<span class="jr"> <a href="#Page_103">103</a></span></dt>
-<dt>Cedar Mesa Sandstone Member, Cutler Formation<span class="jr"> <a href="#Page_22">22</a>, <a href="#Page_102">102</a></span></dt>
-<dt>Chinle Formation<span class="jr"> <a href="#Page_32">32</a>, <a href="#Page_100">100</a>, <a href="#Page_102">102</a>, <a href="#Page_103">103</a></span></dt>
-<dt>&ldquo;Cisco Cutoff&rdquo;<span class="jr"> <a href="#Page_16">16</a></span></dt>
-<dt>Civilian Conservation Corps<span class="jr"> <a href="#Page_2">2</a></span></dt>
-<dt>Cliff dwellers<span class="jr"> <a href="#Page_9">9</a></span></dt>
-<dt>Climate, desert<span class="jr"> <a href="#Page_35">35</a>, <a href="#Page_51">51</a></span></dt>
-<dd>wetter, different landscape produced<span class="jr"> <a href="#Page_37">37</a></span></dd>
-<dt>Collapse, salt anticlines<span class="jr"> <a href="#Page_33">33</a>, <a href="#Page_34">34</a></span></dt>
-<dt>Color photographs, equipment used<span class="jr"> <a href="#Page_8">8</a></span></dt>
-<dt>Colorado National Monument<span class="jr"> <a href="#Page_102">102</a></span></dt>
-<dt>Colorado Plateau, geologic formations included<span class="jr"> <a href="#Page_101">101</a></span></dt>
-<dd>rock formations<span class="jr"> <a href="#Page_103">103</a>, <a href="#Page_104">104</a></span></dd>
-<dd>subdivisions<span class="jr"> <a href="#Page_18">18</a></span></dd>
-<dd>uranium-vanadium mining<span class="jr"> <a href="#Page_14">14</a></span></dd>
-<dt>Colorado Plateaus Province<span class="jr"> <a href="#Page_18">18</a></span></dt>
-<dt>Colorado River, course established<span class="jr"> <a href="#Page_101">101</a></span></dt>
-<dd>nighttime illuminated float trip<span class="jr"> <a href="#Page_16">16</a>, <a href="#Page_52">52</a></span></dd>
-<dt>Colorado River canyon<span class="jr"> <a href="#Page_35">35</a>, <a href="#Page_51">51</a>, <i><a href="#Page_52">52</a></i></span></dt>
-<dt>Cores, salt<span class="jr"> <a href="#Page_100">100</a></span></dt>
-<dt>Corral mine<span class="jr"> <a href="#Page_15">15</a></span></dt>
-<dt>Courthouse syncline<span class="jr"> <a href="#Page_25">25</a>, <a href="#Page_30">30</a>, <a href="#Page_31">31</a>, <a href="#Page_32">32</a>, <a href="#Page_52">52</a>, <a href="#Page_63">63</a>, <a href="#Page_68">68</a>, <a href="#Page_100">100</a></span></dt>
-<dt>Courthouse Towers area<span class="jr"> <a href="#Page_25">25</a>, <i><a href="#Page_63">63</a></i></span></dt>
-<dd>number of arches<span class="jr"> <a href="#Page_41">41</a></span></dd>
-<dt>Courthouse Wash<span class="jr"> <a href="#Page_2">2</a>, <a href="#Page_3">3</a>, <a href="#Page_18">18</a>, <a href="#Page_35">35</a>, <a href="#Page_63">63</a></span></dt>
-<dt>Cove Arch<span class="jr"> <a href="#Page_70">70</a></span></dt>
-<dt>Cove of Caves<span class="jr"> <a href="#Page_70">70</a></span></dt>
-<dt>Crossbedding, Navajo Sandstone<span class="jr"> <a href="#Page_63">63</a>, <a href="#Page_66">66</a>, <a href="#Page_70">70</a></span></dt>
-<dt>Cutler Formation<span class="jr"> <a href="#Page_32">32</a>, <a href="#Page_102">102</a></span></dt>
-<dd>Cedar Mesa Sandstone Member<span class="jr"> <a href="#Page_22">22</a></span></dd>
-<dd>White Rim Sandstone Member<span class="jr"> <a href="#Page_22">22</a></span></dd>
-</dl>
-<div class="pb" id="Page_110">110</div>
-<dl class="index">
-<dt class="center" id="index_D"><b>D</b></dt>
-<dt>Dark Angel<span class="jr"> <a href="#Page_92">92</a></span></dt>
-<dt>De Chelly Sandstone Member, Cutler Formation<span class="jr"> <a href="#Page_102">102</a></span></dt>
-<dt>Dead Horse Point<span class="jr"> <a href="#Page_33">33</a></span></dt>
-<dt>Dedication of the park<span class="jr"> <a href="#Page_8">8</a></span></dt>
-<dt>Delicate Arch<span class="jr"> <a href="#Page_16">16</a>, <a href="#Page_25">25</a>, <a href="#Page_74">74</a>, <a href="#Page_75">75</a>, <a href="#Page_77">77</a></span></dt>
-<dt>Delicate Arch area, number of arches<span class="jr"> <a href="#Page_41">41</a></span></dt>
-<dt>Density, average, Paradox Member<span class="jr"> <a href="#Page_32">32</a></span></dt>
-<dt>Deposition of rock materials, environments<span class="jr"> <i><a href="#Page_20">20</a></i></span></dt>
-<dt>Desert varnish<span class="jr"> <a href="#Page_10">10</a></span></dt>
-<dt>Development of the arches<span class="jr"> <i><a href="#Page_37">37</a></i></span></dt>
-<dt>Devils Garden<span class="jr"> <a href="#Page_2">2</a>, <a href="#Page_5">5</a>, <a href="#Page_25">25</a>, <a href="#Page_79">79</a>, <i><a href="#Page_83">83</a></i>, <a href="#Page_86">86</a></span></dt>
-<dd>fins<span class="jr"> <a href="#Page_42">42</a></span></dd>
-<dd>number of arches<span class="jr"> <a href="#Page_41">41</a></span></dd>
-<dd>trail<span class="jr"> <a href="#Page_88">88</a>, <a href="#Page_92">92</a></span></dd>
-<dt>Dewey Bridge<span class="jr"> <a href="#Page_52">52</a></span></dt>
-<dt>Dewey Bridge Member<span class="jr"> <a href="#Page_46">46</a>, <a href="#Page_63">63</a></span></dt>
-<dd>Entrada Sandstone, composition<span class="jr"> <a href="#Page_41">41</a></span></dd>
-<dd class="ddt">&ldquo;hoodoos and goblins&rdquo;<span class="jr"> <a href="#Page_66">66</a></span></dd>
-<dd class="ddt">park road cutting<span class="jr"> <a href="#Page_57">57</a></span></dd>
-<dd class="ddt">The Windows section<span class="jr"> <a href="#Page_71">71</a></span></dd>
-<dd class="ddt">vertical arches<span class="jr"> <a href="#Page_44">44</a></span></dd>
-<dt>&ldquo;Dewey Road&rdquo;<span class="jr"> <a href="#Page_16">16</a></span></dt>
-<dt>Diapir<span class="jr"> <a href="#Page_83">83</a></span></dt>
-<dt>Differential erosion<span class="jr"> <a href="#Page_42">42</a></span></dt>
-<dt>Dinosaur National Monument<span class="jr"> <a href="#Page_101">101</a>, <a href="#Page_102">102</a></span></dt>
-<dt>Dissimilarity of Arches vs. Canyonlands<span class="jr"> <a href="#Page_23">23</a>, <a href="#Page_24">24</a></span></dt>
-<dt>Double Arch<span class="jr"> <a href="#Page_2">2</a>, <a href="#Page_46">46</a>, <a href="#Page_72">72</a></span></dt>
-<dt>Double O Arch<span class="jr"> <a href="#Page_90">90</a>, <a href="#Page_92">92</a>, <a href="#Page_98">98</a></span></dt>
-<dt>Drainage, Arches National Park<span class="jr"> <a href="#Page_18">18</a></span></dt>
-<dt>Dry Mesa<span class="jr"> <a href="#Page_5">5</a>, <a href="#Page_56">56</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_E"><b>E</b></dt>
-<dt>Eagle Park<span class="jr"> <a href="#Page_25">25</a>, <a href="#Page_98">98</a></span></dt>
-<dd>number of arches<span class="jr"> <a href="#Page_41">41</a></span></dd>
-<dt>Early dwellers<span class="jr"> <i><a href="#Page_9">9</a></i></span></dt>
-<dt>Earthquake, rock offset along bedding plane<span class="jr"> <a href="#Page_63">63</a></span></dt>
-<dt>Egyptian queen, arch resembling<span class="jr"> <a href="#Page_63">63</a></span></dt>
-<dt>Eisenhower, Dwight D., Mission 66<span class="jr"> <a href="#Page_4">4</a></span></dt>
-<dt>Elephant Butte<span class="jr"> <a href="#Page_72">72</a></span></dt>
-<dt>Elephant Butte folds<span class="jr"> <a href="#Page_68">68</a></span></dt>
-<dt>Elizondo, Emmett<span class="jr"> <a href="#Page_13">13</a></span></dt>
-<dt>Entrada Sandstone<span class="jr"> <a href="#Page_23">23</a>, <a href="#Page_74">74</a>, <a href="#Page_102">102</a>, <a href="#Page_103">103</a></span></dt>
-<dd>arches, modes of origin<span class="jr"> <a href="#Page_42">42</a></span></dd>
-<dd>caves<span class="jr"> <a href="#Page_9">9</a></span></dd>
-<dd>cut by normal fault<span class="jr"> <a href="#Page_57">57</a></span></dd>
-<dd>Moab Member<span class="jr"> <a href="#Page_24">24</a></span></dd>
-<dd>no water found<span class="jr"> <a href="#Page_87">87</a></span></dd>
-<dt>Environments of deposition<span class="jr"> <i><a href="#Page_20">20</a></i></span></dt>
-<dt>Erosion<span class="jr"> <a href="#Page_99">99</a></span></dt>
-<dd>Colorado Plateau<span class="jr"> <i><a href="#Page_33">33</a></i></span></dd>
-<dt>Evaporation basins<span class="jr"> <a href="#Page_99">99</a></span></dt>
-<dt>Evaporites<span class="jr"> <a href="#Page_30">30</a></span></dt>
-<dt>Eye of The Whale<span class="jr"> <a href="#Page_69">69</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_F"><b>F</b></dt>
-<dt>Facies changes<span class="jr"> <a href="#Page_22">22</a></span></dt>
-<dt>&ldquo;Father of the monument,&rdquo; J. W. Williams<span class="jr"> <a href="#Page_1">1</a>, <a href="#Page_4">4</a></span></dt>
-<dt>Faults, Cache Valley anticline<span class="jr"> <a href="#Page_34">34</a></span></dt>
-<dd>Salt Valley anticline<span class="jr"> <a href="#Page_34">34</a></span></dd>
-<dt>Fiery Furnace<span class="jr"> <a href="#Page_25">25</a>, <a href="#Page_42">42</a>, <a href="#Page_73">73</a>, <i><a href="#Page_79">79</a></i>, <a href="#Page_83">83</a></span></dt>
-<dd>number of arches<span class="jr"> <a href="#Page_41">41</a></span></dd>
-<dt>Fins<span class="jr"> <a href="#Page_63">63</a>, <a href="#Page_79">79</a></span></dt>
-<dt>Float trip, nighttime illuminated, down Colorado River<span class="jr"> <a href="#Page_52">52</a></span></dt>
-<dt>Folds<span class="jr"> <i><a href="#Page_24">24</a></i>, <a href="#Page_30">30</a>, <a href="#Page_100">100</a></span></dt>
-<dt>Four-wheel-drive vehicles<span class="jr"> <a href="#Page_69">69</a></span></dt>
-<dt>Fractures<span class="jr"> <i><a href="#Page_24">24</a></i></span></dt>
-<dt>Fremont people, occupation of area<span class="jr"> <a href="#Page_9">9</a></span></dt>
-<dd>pictographs<span class="jr"> <a href="#Page_10">10</a></span></dd>
-<dt>Frost, prying action<span class="jr"> <a href="#Page_42">42</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_G"><b>G</b></dt>
-<dt>Garden of Eden<span class="jr"> <a href="#Page_50">50</a>, <a href="#Page_69">69</a>, <a href="#Page_70">70</a></span></dt>
-<dt>Gas exploration, deep tests<span class="jr"> <a href="#Page_15">15</a>, <a href="#Page_99">99</a></span></dt>
-<dt>Geographic setting<span class="jr"> <i><a href="#Page_18">18</a></i></span></dt>
-<dt>Geologic age of rocks in park<span class="jr"> <i><a href="#Page_98">98</a></i></span></dt>
-<dt>Geologic events forming the Colorado Plateau<span class="jr"> <i><a href="#Page_98">98</a></i></span></dt>
-<dt>Geologic history, summary<span class="jr"> <i><a href="#Page_98">98</a></i></span></dt>
-<dt>Geologic Time Spiral<span class="jr"> <a href="#Page_101">101</a>, <a href="#Page_103">103</a></span></dt>
-<dt>Geology, at the park entrance<span class="jr"> <a href="#Page_57">57</a></span></dt>
-<dt>Glen Canyon Group<span class="jr"> <a href="#Page_52">52</a>, <a href="#Page_102">102</a>, <a href="#Page_103">103</a></span></dt>
-<dt>Glen Canyon National Recreation Area<span class="jr"> <a href="#Page_101">101</a>, <a href="#Page_103">103</a></span></dt>
-<dt>Goblin Valley State Park<span class="jr"> <a href="#Page_66">66</a>, <a href="#Page_103">103</a></span></dt>
-<dt>Gould, Lawrence M.<span class="jr"> <a href="#Page_1">1</a></span></dt>
-<dt>Goulding, Harry, first person to drive into The Windows section<span class="jr"> <a href="#Page_2">2</a>, <a href="#Page_69">69</a></span></dt>
-<dt>Grabens<span class="jr"> <a href="#Page_34">34</a></span></dt>
-<dt>Grand Canyon National Park and National Monument<span class="jr"> <a href="#Page_102">102</a></span></dt>
-<dt>Gravity anomalies, Salt Valley<span class="jr"> <a href="#Page_32">32</a></span></dt>
-<dt>Green River<span class="jr"> <a href="#Page_103">103</a></span></dt>
-<dt>Ground water<span class="jr"> <a href="#Page_41">41</a></span></dt>
-<dt>&ldquo;Guide to an Auto Tour of Arches National Park,&rdquo; (The)<span class="jr"> <a href="#Page_5">5</a>, <a href="#Page_50">50</a>, <a href="#Page_51">51</a>, <a href="#Page_72">72</a></span></dt>
-<dt>Gulf of California<span class="jr"> <a href="#Page_33">33</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_H"><b>H</b></dt>
-<dt>Hastier, (Mrs.) Hazel Wolfe<span class="jr"> <a href="#Page_13">13</a></span></dt>
-<dt>Headquarters area<span class="jr"> <i><a href="#Page_57">57</a></i></span></dt>
-<dt>Henry Mountains<span class="jr"> <a href="#Page_101">101</a></span></dt>
-<dt>Herdina Park<span class="jr"> <a href="#Page_25">25</a>, <a href="#Page_69">69</a></span></dt>
-<dd>number of arches<span class="jr"> <a href="#Page_41">41</a></span></dd>
-<dt>Hermosa Formation, Paradox Member<span class="jr"> <a href="#Page_23">23</a>, <a href="#Page_25">25</a>, <a href="#Page_29">29</a>, <a href="#Page_30">30</a>, <a href="#Page_32">32</a></span></dt>
-<dt>History, early<span class="jr"> <i><a href="#Page_9">9</a></i></span></dt>
-<dd>geologic, summary<span class="jr"> <i><a href="#Page_98">98</a></i></span></dd>
-<dt>&ldquo;Hoodoos and goblins&rdquo;<span class="jr"> <a href="#Page_66">66</a>, <a href="#Page_103">103</a></span></dt>
-<dt>Hoover, Herbert, proclamation<span class="jr"> <a href="#Page_1">1</a></span></dt>
-<dt>Horizontal arches<span class="jr"> <a href="#Page_44">44</a></span></dt>
-<dt>Horseshoe Canyon, pictographs<span class="jr"> <a href="#Page_10">10</a></span></dt>
-<dt>Horseshoe Canyon Detached Unit of Canyonlands<span class="jr"> <a href="#Page_23">23</a></span></dt>
-<dt>Humid regions, subdued rounded landforms<span class="jr"> <a href="#Page_37">37</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_I"><b>I</b></dt>
-<dt>Igneous rocks<span class="jr"> <a href="#Page_22">22</a>, <a href="#Page_99">99</a></span></dt>
-<dt>&ldquo;Indian-Head Arch&rdquo;<span class="jr"> <a href="#Page_98">98</a></span></dt>
-<dt>Iron in the rocks<span class="jr"> <a href="#Page_23">23</a></span></dt>
-<dt>Island in the Sky<span class="jr"> <a href="#Page_102">102</a></span></dt>
-</dl>
-<div class="pb" id="Page_111">111</div>
-<dl class="index">
-<dt class="center" id="index_J"><b>J</b></dt>
-<dt>Jeep trail<span class="jr"> <a href="#Page_69">69</a>, <a href="#Page_70">70</a></span></dt>
-<dt>Johnson, Lyndon B., proclamation<span class="jr"> <a href="#Page_2">2</a></span></dt>
-<dt>Joints<span class="jr"> <i><a href="#Page_24">24</a></i>, <a href="#Page_34">34</a>, <a href="#Page_100">100</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_K"><b>K</b></dt>
-<dt>Kayenta Formation<span class="jr"> <a href="#Page_35">35</a>, <a href="#Page_52">52</a>, <a href="#Page_102">102</a>, <a href="#Page_103">103</a></span></dt>
-<dt>Kerr, Bob<span class="jr"> <a href="#Page_105">105</a></span></dt>
-<dt>Klondike Bluffs<span class="jr"> <a href="#Page_25">25</a>, <a href="#Page_69">69</a>, <i><a href="#Page_82">82</a></i>, <a href="#Page_83">83</a></span></dt>
-<dd>number of arches<span class="jr"> <a href="#Page_41">41</a></span></dd>
-</dl>
-<dl class="index">
-<dt class="center" id="index_L"><b>L</b></dt>
-<dt>La Sal Mountains<span class="jr"> <a href="#Page_22">22</a>, <a href="#Page_63">63</a>, <a href="#Page_77">77</a>, <a href="#Page_101">101</a></span></dt>
-<dd>artifacts<span class="jr"> <a href="#Page_9">9</a></span></dd>
-<dt>Lake Mead<span class="jr"> <a href="#Page_33">33</a></span></dt>
-<dt>Lake Powell<span class="jr"> <a href="#Page_33">33</a></span></dt>
-<dt>Land forms, formation in the park<span class="jr"> <a href="#Page_33">33</a></span></dt>
-<dt>Landscape Arch<span class="jr"> <a href="#Page_16">16</a>, <a href="#Page_77">77</a>, <a href="#Page_88">88</a></span></dt>
-<dd>second known ascent<span class="jr"> <a href="#Page_90">90</a></span></dd>
-<dt>Larson, Tommy<span class="jr"> <a href="#Page_13">13</a></span></dt>
-<dt>Lloyd, Sherman P., Representative<span class="jr"> <a href="#Page_8">8</a></span></dt>
-<dt>Lohman, (Mrs.) Ruth<span class="jr"> <a href="#Page_105">105</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_M"><b>M</b></dt>
-<dt>Mahan, Russel L.<span class="jr"> <a href="#Page_2">2</a></span></dt>
-<dt>Mancos Shale<span class="jr"> <a href="#Page_32">32</a>, <a href="#Page_100">100</a></span></dt>
-<dt>Maxwell, Ross A., investigation of caves<span class="jr"> <a href="#Page_9">9</a>, <a href="#Page_10">10</a></span></dt>
-<dt>May, David<span class="jr"> <a href="#Page_40">40</a>, <a href="#Page_105">105</a></span></dt>
-<dt>Melich, Mitchell, Solicitor General<span class="jr"> <a href="#Page_8">8</a></span></dt>
-<dt>Mesaverde Group<span class="jr"> <a href="#Page_32">32</a>, <a href="#Page_103">103</a></span></dt>
-<dt>Mesaverde National Park<span class="jr"> <a href="#Page_103">103</a></span></dt>
-<dt>Metamorphic rocks<span class="jr"> <a href="#Page_22">22</a>, <a href="#Page_99">99</a></span></dt>
-<dt>Metric unit conversion factors<span class="jr"> <i><a href="#Page_2">2</a></i></span></dt>
-<dt>Mikesell, Carl<span class="jr"> <a href="#Page_105">105</a></span></dt>
-<dt>Miller, Joe<span class="jr"> <a href="#Page_105">105</a></span></dt>
-<dt>Mission 66, presidential and congressional support<span class="jr"> <a href="#Page_4">4</a></span></dt>
-<dt>Mississippi River sternwheeler replica<span class="jr"> <a href="#Page_8">8</a></span></dt>
-<dt>Moab, uranium-vanadium mill<span class="jr"> <a href="#Page_14">14</a></span></dt>
-<dt>Moab bridge<span class="jr"> <a href="#Page_52">52</a></span></dt>
-<dt>Moab Canyon<span class="jr"> <a href="#Page_15">15</a>, <a href="#Page_18">18</a></span></dt>
-<dt>Moab fault<span class="jr"> <a href="#Page_26">26</a>, <a href="#Page_57">57</a></span></dt>
-<dt>Moab Lions Club<span class="jr"> <a href="#Page_1">1</a>, <a href="#Page_8">8</a></span></dt>
-<dt>&ldquo;Moab Mail Road&rdquo;<span class="jr"> <a href="#Page_16">16</a></span></dt>
-<dt>Moab Member, Entrada Sandstone<span class="jr"> <a href="#Page_24">24</a>, <a href="#Page_35">35</a></span></dt>
-<dd>Entrada Sandstone, Broken Arch<span class="jr"> <a href="#Page_46">46</a></span></dd>
-<dd>composition<span class="jr"> <a href="#Page_41">41</a></span></dd>
-<dt>&ldquo;Moab panel&rdquo;<span class="jr"> <a href="#Page_10">10</a></span></dt>
-<dt>Moab-Spanish Valley anticline<span class="jr"> <a href="#Page_26">26</a></span></dt>
-<dt>Moab Valley<span class="jr"> <a href="#Page_57">57</a></span></dt>
-<dt>Moab Valley-Seven Mile anticline<span class="jr"> <a href="#Page_100">100</a>, <a href="#Page_101">101</a></span></dt>
-<dt>Moenkopi Formation<span class="jr"> <a href="#Page_32">32</a>, <a href="#Page_102">102</a>, <a href="#Page_103">103</a></span></dt>
-<dt>Monoliths<span class="jr"> <a href="#Page_63">63</a></span></dt>
-<dt>Monument, beginning<span class="jr"> <i><a href="#Page_1">1</a></i></span></dt>
-<dt>Monument Valley<span class="jr"> <a href="#Page_101">101</a>, <a href="#Page_102">102</a></span></dt>
-<dt>Morrison Formation<span class="jr"> <a href="#Page_32">32</a>, <a href="#Page_101">101</a></span></dt>
-<dt>Morton, Rogers C. B., Secretary of the Interior<span class="jr"> <a href="#Page_8">8</a></span></dt>
-<dt>Moss, Frank E., Senator<span class="jr"> <a href="#Page_8">8</a></span></dt>
-<dt>Moss Back Member, Chinle Formation<span class="jr"> <a href="#Page_15">15</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_N"><b>N</b></dt>
-<dt><a id="xnps">National Park Service</a><span class="jr"> <a href="#Page_8">8</a>, <a href="#Page_12">12</a>, <a href="#Page_40">40</a>, <a href="#Page_75">75</a>, <a href="#Page_90">90</a></span></dt>
-<dt>Natural Bridges National Monument<span class="jr"> <a href="#Page_3">3</a>, <a href="#Page_37">37</a>, <a href="#Page_40">40</a>, <a href="#Page_102">102</a></span></dt>
-<dt>Navajo Arch<span class="jr"> <a href="#Page_90">90</a></span></dt>
-<dt>Navajo Sandstone<span class="jr"> <a href="#Page_24">24</a>, <a href="#Page_35">35</a>, <a href="#Page_52">52</a>, <a href="#Page_103">103</a></span></dt>
-<dd>canyon floor<span class="jr"> <a href="#Page_63">63</a></span></dd>
-<dd>crossbedding<span class="jr"> <a href="#Page_63">63</a>, <a href="#Page_66">66</a>, <a href="#Page_70">70</a></span></dd>
-<dd>park road cutting<span class="jr"> <a href="#Page_57">57</a></span></dd>
-<dd>water supply<span class="jr"> <a href="#Page_57">57</a>, <a href="#Page_87">87</a></span></dd>
-<dt>Navajo Tribe<span class="jr"> <a href="#Page_102">102</a></span></dt>
-<dt>Needles section, The, Canyonlands National Park<span class="jr"> <a href="#Page_16">16</a>, <a href="#Page_102">102</a></span></dt>
-<dt>Newell, (Mrs.) Maxine<span class="jr"> <a href="#Page_12">12</a>, <a href="#Page_105">105</a></span></dt>
-<dt>Nixon, Richard M., Congressional Bill<span class="jr"> <a href="#Page_5">5</a></span></dt>
-<dt>North Window<span class="jr"> <a href="#Page_40">40</a>, <a href="#Page_68">68</a>, <a href="#Page_71">71</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_O"><b>O</b></dt>
-<dt>Oil exploration<span class="jr"> <a href="#Page_15">15</a></span></dt>
-<dd>Cane Creek anticline<span class="jr"> <a href="#Page_24">24</a></span></dd>
-<dd>deep tests<span class="jr"> <a href="#Page_99">99</a></span></dd>
-<dt>Origin of the arches<span class="jr"> <i><a href="#Page_37">37</a></i></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_P"><b>P</b></dt>
-<dt>Pacific Northwest Pipeline<span class="jr"> <a href="#Page_15">15</a></span></dt>
-<dt>Painted Desert<span class="jr"> <a href="#Page_102">102</a></span></dt>
-<dt>Panorama Point<span class="jr"> <a href="#Page_73">73</a></span></dt>
-<dt>Parade of Elephants<span class="jr"> <a href="#Page_72">72</a></span></dt>
-<dt>Paradox basin<span class="jr"> <a href="#Page_23">23</a></span></dt>
-<dt>Paradox Member, Hermosa Formation<span class="jr"> <a href="#Page_23">23</a>, <a href="#Page_25">25</a>, <a href="#Page_29">29</a>, <a href="#Page_30">30</a>, <a href="#Page_82">82</a>, <a href="#Page_99">99</a></span></dt>
-<dd>Hermosa Formation, average density<span class="jr"> <a href="#Page_32">32</a></span></dd>
-<dd class="ddt">upward intrusion<span class="jr"> <a href="#Page_34">34</a></span></dd>
-<dt>Park, a trip through<span class="jr"> <i><a href="#Page_52">52</a></i></span></dt>
-<dd>dedication<span class="jr"> <a href="#Page_8">8</a></span></dd>
-<dd>how to see<span class="jr"> <i><a href="#Page_50">50</a></i></span></dd>
-<dd>improvements<span class="jr"> <a href="#Page_4">4</a></span></dd>
-<dt>Park Avenue, trail<span class="jr"> <a href="#Page_63">63</a></span></dt>
-<dt>Park Service. <i>See</i> <a href="#xnps">National Park Service</a>.</dt>
-<dt>Partition Arch<span class="jr"> <a href="#Page_90">90</a></span></dt>
-<dt>Petrified dunes<span class="jr"> <a href="#Page_63">63</a>, <a href="#Page_66">66</a></span></dt>
-<dt>Petrified Forest National Park<span class="jr"> <a href="#Page_102">102</a></span></dt>
-<dt>Petroglyphs, Ute<span class="jr"> <a href="#Page_10">10</a>, <a href="#Page_75">75</a></span></dt>
-<dt>Pictographs, Fremont people<span class="jr"> <a href="#Page_10">10</a></span></dt>
-<dt>Pine Tree Arch<span class="jr"> <a href="#Page_90">90</a></span></dt>
-<dt>Pi&ntilde;on pines<span class="jr"> <a href="#Page_86">86</a></span></dt>
-<dt>Pipeline scars, Pacific Northwest Pipeline<span class="jr"> <a href="#Page_15">15</a></span></dt>
-<dt>Plateau, uplift and erosion<span class="jr"> <i><a href="#Page_33">33</a></i></span></dt>
-<dt>Potash occurrence<span class="jr"> <a href="#Page_15">15</a></span></dt>
-<dt>Pothole Arch<span class="jr"> <a href="#Page_50">50</a>, <a href="#Page_73">73</a></span></dt>
-<dt>Pothole arches<span class="jr"> <a href="#Page_44">44</a></span></dt>
-<dt>Powell, John Wesley, Canyonlands National Park<span class="jr"> <a href="#Page_15">15</a></span></dt>
-<dt>Professor Valley<span class="jr"> <a href="#Page_56">56</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_R"><b>R</b></dt>
-<dt>Rainbow Bridge National Monument<span class="jr"> <a href="#Page_103">103</a></span></dt>
-<dt>Rainwater<span class="jr"> <a href="#Page_41">41</a>, <a href="#Page_42">42</a></span></dt>
-<dt>Rampton, Calvin L., Utah Governor<span class="jr"> <a href="#Page_8">8</a></span></dt>
-<dt>Reading, additional<span class="jr"> <i><a href="#Page_104">104</a></i></span></dt>
-<dt>References, selected<span class="jr"> <i><a href="#Page_105">105</a></i></span></dt>
-<dt class="pb" id="Page_112">112</dt>
-<dt>Relief map, shaded, Arches National Park, described<span class="jr"> <a href="#Page_18">18</a>, <a href="#Page_19">19</a></span></dt>
-<dt>Ribbon Arch<span class="jr"> <a href="#Page_72">72</a></span></dt>
-<dt>Richardson Amphitheater<span class="jr"> <a href="#Page_56">56</a></span></dt>
-<dt>Richardson, Professor<span class="jr"> <a href="#Page_56">56</a></span></dt>
-<dt>Rico Formation<span class="jr"> <a href="#Page_23">23</a></span></dt>
-<dt>Rison, (Mrs.) Esther Stanley<span class="jr"> <a href="#Page_13">13</a></span></dt>
-<dt>Rock formations, sculptured by erosion<span class="jr"> <a href="#Page_35">35</a></span></dt>
-<dt>Rock openings, natural, types<span class="jr"> <a href="#Page_37">37</a></span></dt>
-<dt>Rock types in the park<span class="jr"> <a href="#Page_35">35</a></span></dt>
-<dt>Roosevelt, Franklin D., proclamation<span class="jr"> <a href="#Page_2">2</a></span></dt>
-<dt>Rumel, Hal, photographer<span class="jr"> <a href="#Page_77">77</a></span></dt>
-<dt>&ldquo;Run, Cougar, Run&rdquo;<span class="jr"> <a href="#Page_16">16</a>, <a href="#Page_56">56</a>, <a href="#Page_75">75</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_S"><b>S</b></dt>
-<dt>Sagers Wash syncline<span class="jr"> <a href="#Page_86">86</a></span></dt>
-<dt>Salt, occurrence<span class="jr"> <a href="#Page_15">15</a></span></dt>
-<dd>properties critical to formation of salt anticlines<span class="jr"> <a href="#Page_30">30</a></span></dd>
-<dt>Salt anticlines<span class="jr"> <a href="#Page_30">30</a>, <a href="#Page_31">31</a>, <a href="#Page_100">100</a></span></dt>
-<dd>collapse<span class="jr"> <a href="#Page_33">33</a>, <a href="#Page_34">34</a></span></dd>
-<dt>Salt-bearing rock<span class="jr"> <a href="#Page_83">83</a></span></dt>
-<dt>Salt rolls<span class="jr"> <a href="#Page_31">31</a></span></dt>
-<dt>Salt Valley<span class="jr"> <a href="#Page_2">2</a>, <a href="#Page_68">68</a>, <a href="#Page_73">73</a>, <a href="#Page_77">77</a>, <i><a href="#Page_82">82</a></i>, <a href="#Page_83">83</a>, <a href="#Page_92">92</a></span></dt>
-<dd>gravity anomalies<span class="jr"> <a href="#Page_32">32</a></span></dd>
-<dt>Salt Valley anticline<span class="jr"> <a href="#Page_25">25</a>, <a href="#Page_30">30</a>, <a href="#Page_31">31</a>, <a href="#Page_32">32</a>, <a href="#Page_73">73</a>, <a href="#Page_100">100</a>, <a href="#Page_101">101</a></span></dt>
-<dd>collapse<span class="jr"> <a href="#Page_34">34</a></span></dd>
-<dd>fins<span class="jr"> <a href="#Page_42">42</a></span></dd>
-<dt>Salt Valley Wash<span class="jr"> <a href="#Page_3">3</a>, <a href="#Page_74">74</a>, <a href="#Page_82">82</a>, <a href="#Page_83">83</a></span></dt>
-<dt>Salt Wash<span class="jr"> <a href="#Page_35">35</a>, <a href="#Page_55">55</a></span></dt>
-<dd>Anasazi ruins<span class="jr"> <a href="#Page_9">9</a></span></dd>
-<dd>drainage<span class="jr"> <a href="#Page_18">18</a></span></dd>
-<dd>grabens<span class="jr"> <a href="#Page_34">34</a></span></dd>
-<dd>sandstone caves near<span class="jr"> <a href="#Page_10">10</a></span></dd>
-<dt>Salt Wash Sandstone Member, Morrison Formation<span class="jr"> <a href="#Page_14">14</a></span></dt>
-<dt>San Juan Basin, natural gas<span class="jr"> <a href="#Page_15">15</a></span></dt>
-<dt>San Rafael Swell<span class="jr"> <a href="#Page_101">101</a>, <a href="#Page_103">103</a></span></dt>
-<dt>Sand Dune Arch<span class="jr"> <a href="#Page_79">79</a></span></dt>
-<dt>Sandstone fins<span class="jr"> <a href="#Page_41">41</a>, <a href="#Page_42">42</a></span></dt>
-<dt>Schaafsma, Polly, quoted<span class="jr"> <a href="#Page_10">10</a>, <a href="#Page_12">12</a></span></dt>
-<dt>Scenic drive, Moab to Cisco<span class="jr"> <a href="#Page_16">16</a></span></dt>
-<dt>&ldquo;Scenic Inch,&rdquo; Pacific Northwest Pipeline<span class="jr"> <a href="#Page_15">15</a></span></dt>
-<dt>Sedimentary rocks<span class="jr"> <a href="#Page_20">20</a></span></dt>
-<dd>modes of deposition<span class="jr"> <a href="#Page_99">99</a></span></dd>
-<dt>Seven Mile-Moab Valley anticline<span class="jr"> <a href="#Page_26">26</a>, <a href="#Page_32">32</a>, <a href="#Page_57">57</a></span></dt>
-<dt>Sevenmile Canyon<span class="jr"> <a href="#Page_15">15</a></span></dt>
-<dt>Sheep Rock<span class="jr"> <a href="#Page_63">63</a></span></dt>
-<dt>Skyline Arch<span class="jr"> <a href="#Page_83">83</a></span></dt>
-<dt>Slick Rock Member, Entrada Sandstone<span class="jr"> <a href="#Page_34">34</a></span></dt>
-<dd>Entrada Sandstone, composition<span class="jr"> <a href="#Page_41">41</a></span></dd>
-<dd class="ddt">high fins and pinnacles<span class="jr"> <a href="#Page_63">63</a>, <a href="#Page_79">79</a>, <a href="#Page_86">86</a></span></dd>
-<dd class="ddt">hiking trail between fins<span class="jr"> <a href="#Page_90">90</a></span></dd>
-<dd class="ddt">park road cutting<span class="jr"> <a href="#Page_57">57</a></span></dd>
-<dd class="ddt">salmon<span class="jr"> <a href="#Page_77">77</a></span></dd>
-<dd class="ddt">The Windows section<span class="jr"> <a href="#Page_71">71</a></span></dd>
-<dd class="ddt">Tunnel Arch<span class="jr"> <a href="#Page_46">46</a></span></dd>
-<dd class="ddt">vertical arches<span class="jr"> <a href="#Page_42">42</a>, <a href="#Page_44">44</a></span></dd>
-<dt>Slumping of sediments, irregular<span class="jr"> <a href="#Page_50">50</a></span></dt>
-<dt>Snow<span class="jr"> <a href="#Page_41">41</a>, <a href="#Page_51">51</a></span></dt>
-<dt>Sonic booms, dangers posed to arches<span class="jr"> <a href="#Page_16">16</a>, <a href="#Page_17">17</a></span></dt>
-<dt>South Window<span class="jr"> <a href="#Page_40">40</a>, <a href="#Page_68">68</a>, <a href="#Page_71">71</a></span></dt>
-<dt>Spanish explorers<span class="jr"> <a href="#Page_12">12</a></span></dt>
-<dd>introduction of horses to this country<span class="jr"> <a href="#Page_10">10</a></span></dd>
-<dt>Squaw Flat Campground<span class="jr"> <a href="#Page_16">16</a></span></dt>
-<dt>Stanley, Esther<span class="jr"> <a href="#Page_13">13</a></span></dt>
-<dd>(Mrs.) Flora<span class="jr"> <a href="#Page_13">13</a></span></dd>
-<dd>Volna<span class="jr"> <a href="#Page_13">13</a></span></dd>
-<dt>Stevens, Dale J.<span class="jr"> <a href="#Page_40">40</a>, <a href="#Page_41">41</a>, <a href="#Page_63">63</a>, <a href="#Page_90">90</a>, <a href="#Page_98">98</a></span></dt>
-<dt>Strata, lateral changes across the park<span class="jr"> <a href="#Page_22">22</a></span></dt>
-<dt>Sundance Kid<span class="jr"> <a href="#Page_12">12</a></span></dt>
-<dt>Sunset Crater National Monument<span class="jr"> <a href="#Page_103">103</a></span></dt>
-<dt>Supersonic flights banned, Moab-Times Independent<span class="jr"> <a href="#Page_17">17</a></span></dt>
-<dt>Suspension bridge, Colorado River<span class="jr"> <a href="#Page_16">16</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_T"><b>T</b></dt>
-<dt>Tanner, (Mrs.) Faun McConkie<span class="jr"> <a href="#Page_1">1</a></span></dt>
-<dt>Taylor, L. L. (Bish)<span class="jr"> <a href="#Page_1">1</a></span></dt>
-<dt>Temperatures<span class="jr"> <a href="#Page_51">51</a></span></dt>
-<dt>&ldquo;The Guide to an Auto Tour of Arches National Park&rdquo;<span class="jr"> <a href="#Page_5">5</a>, <a href="#Page_50">50</a>, <a href="#Page_51">51</a>, <a href="#Page_72">72</a></span></dt>
-<dt>The Needles section, Canyonlands National Park<span class="jr"> <a href="#Page_16">16</a>, <a href="#Page_102">102</a></span></dt>
-<dt>The Windows section<span class="jr"> <a href="#Page_25">25</a>, <a href="#Page_41">41</a>, <a href="#Page_46">46</a>, <a href="#Page_51">51</a>, <a href="#Page_66">66</a>, <i><a href="#Page_68">68</a></i>, <a href="#Page_69">69</a>, <a href="#Page_70">70</a></span></dt>
-<dt>Three Gossips<span class="jr"> <a href="#Page_63">63</a></span></dt>
-<dt>Three Penguins<span class="jr"> <a href="#Page_57">57</a></span></dt>
-<dt>Tower Arch<span class="jr"> <a href="#Page_83">83</a></span></dt>
-<dt>Tunnel Arch<span class="jr"> <a href="#Page_40">40</a>, <a href="#Page_46">46</a>, <a href="#Page_90">90</a></span></dt>
-<dt>Turnbow, Mary<span class="jr"> <a href="#Page_1">1</a></span></dt>
-<dt>Turnbow cabin<span class="jr"> <a href="#Page_13">13</a></span></dt>
-<dt>Turret Arch<span class="jr"> <a href="#Page_68">68</a>, <a href="#Page_71">71</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_U"><b>U</b></dt>
-<dt>Uncompahgre Highland<span class="jr"> <a href="#Page_23">23</a>, <a href="#Page_99">99</a>, <a href="#Page_100">100</a></span></dt>
-<dt>Uncompahgre Plateau<span class="jr"> <a href="#Page_23">23</a>, <a href="#Page_99">99</a></span></dt>
-<dt>Uplift, Colorado Plateau<span class="jr"> <i><a href="#Page_33">33</a></i></span></dt>
-<dt>Upper Devils Garden<span class="jr"> <a href="#Page_98">98</a></span></dt>
-<dd>number of arches<span class="jr"> <a href="#Page_41">41</a></span></dd>
-<dt>Uranium mines<span class="jr"> <a href="#Page_14">14</a></span></dt>
-<dt>Ute petroglyphs<span class="jr"> <a href="#Page_10">10</a>, <a href="#Page_75">75</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_V"><b>V</b></dt>
-<dt>Vanadium mines<span class="jr"> <a href="#Page_14">14</a></span></dt>
-<dt>Vegetation<span class="jr"> <a href="#Page_37">37</a></span></dt>
-<dt>Vertical arches<span class="jr"> <a href="#Page_42">42</a>, <a href="#Page_44">44</a></span></dt>
-<dt>Visitor Center<span class="jr"> <a href="#Page_50">50</a>, <a href="#Page_51">51</a>, <a href="#Page_57">57</a>, <a href="#Page_86">86</a></span></dt>
-<dt>Volz, J. Leonard<span class="jr"> <a href="#Page_8">8</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_W"><b>W</b></dt>
-<dt>Walker, Lester<span class="jr"> <a href="#Page_13">13</a></span></dt>
-<dt>Wall Arch<span class="jr"> <a href="#Page_90">90</a></span></dt>
-<dt>Walt Disney crew, &ldquo;Run, Cougar, Run&rdquo;<span class="jr"> <a href="#Page_75">75</a></span></dt>
-<dt>Wasatch Formation<span class="jr"> <a href="#Page_32">32</a></span></dt>
-<dt>Water supply, Navajo Sandstone<span class="jr"> <a href="#Page_57">57</a></span></dt>
-<dd>to the campground<span class="jr"> <a href="#Page_87">87</a></span></dd>
-<dt class="pb" id="Page_113">113</dt>
-<dt>White Rim Sandstone Member, Cutler Formation<span class="jr"> <a href="#Page_22">22</a></span></dt>
-<dt>Wild Bunch, The<span class="jr"> <a href="#Page_12">12</a></span></dt>
-<dt>Williams, J. W.<span class="jr"> <a href="#Page_1">1</a>, <a href="#Page_4">4</a></span></dt>
-<dt>Wilson, Bates<span class="jr"> <a href="#Page_1">1</a>, <a href="#Page_3">3</a>, <a href="#Page_105">105</a></span></dt>
-<dt>Wilson, (Mrs.) Bates<span class="jr"> <a href="#Page_3">3</a></span></dt>
-<dt>Windows, distinguished from arches<span class="jr"> <i><a href="#Page_40">40</a></i></span></dt>
-<dt>Windows section, The<span class="jr"> <a href="#Page_25">25</a>, <a href="#Page_46">46</a>, <a href="#Page_51">51</a>, <a href="#Page_66">66</a>, <i><a href="#Page_68">68</a></i>, <a href="#Page_69">69</a>, <a href="#Page_70">70</a></span></dt>
-<dd>number of arches<span class="jr"> <a href="#Page_41">41</a></span></dd>
-<dt>Wingate Sandstone<span class="jr"> <a href="#Page_35">35</a>, <a href="#Page_87">87</a>, <a href="#Page_102">102</a>, <a href="#Page_103">103</a></span></dt>
-<dt>Wirth, Conrad L.<span class="jr"> <a href="#Page_4">4</a></span></dt>
-<dt>Wolfe cabin<span class="jr"> <a href="#Page_1">1</a>, <a href="#Page_3">3</a>, <a href="#Page_12">12</a>, <a href="#Page_13">13</a>, <a href="#Page_14">14</a></span></dt>
-<dt>Wolfe, Fred<span class="jr"> <a href="#Page_12">12</a>, <a href="#Page_13">13</a></span></dt>
-<dt>Wolfe, John Wesley<span class="jr"> <a href="#Page_12">12</a>, <a href="#Page_13">13</a></span></dt>
-<dt>Wolfe&rsquo;s Bar-DX Ranch<span class="jr"> <a href="#Page_9">9</a>, <a href="#Page_10">10</a>, <a href="#Page_14">14</a>, <a href="#Page_74">74</a>, <a href="#Page_75">75</a></span></dt>
-<dt>Wupatki National Monument<span class="jr"> <a href="#Page_102">102</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_Y"><b>Y</b></dt>
-<dt>Yellow Cat area (Thompson&rsquo;s area)<span class="jr"> <a href="#Page_14">14</a></span></dt>
-<dt>Yellow Cat Flat<span class="jr"> <a href="#Page_86">86</a></span></dt>
-<dt>Yellow Cat mining district<span class="jr"> <a href="#Page_83">83</a></span></dt>
-</dl>
-<dl class="index">
-<dt class="center" id="index_Z"><b>Z</b></dt>
-<dt>Zion National Park<span class="jr"> <a href="#Page_103">103</a></span></dt>
-</dl>
-<p><span class="lr"><span class="smaller">&#9733;U.S. GOVERNMENT PRINTING OFFICE: 1975&mdash;679-138</span></span></p>
-<div class="img">
-<img src="images/pmg092.jpg" alt="U. S. Department of the Interior, March 3, 1849" width="400" height="401" />
-</div>
-<h2 id="c27"><br /><span class="small">Transcriber&rsquo;s Notes</span></h2>
-<ul><li>Retained publication information from the printed edition: this eBook is public-domain in the country of publication.</li>
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