Stanley William Lohman

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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) . ”

“ 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 41⁄2 percent of the age of the Earth as a whole. ”

“ 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) . ”

“ 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. ”

“ 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) . ”

“ 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. ”

“ 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. ”

“ 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 51 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. ”

“ 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. ”

“ 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) . ”

“ 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 87 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. ”

“ 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. ”

“ 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. ”

“ Visitors having four-wheel-drive vehicles may wish to drive at least as far as Eye of The Whale (fig. 34) , 70 which is about 2 miles northwest of Balanced Rock. There are several picnic tables at the beginning of this jeep trail, but no water.
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 21⁄2 miles to the main parking lots in The Windows section. ”

“ 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. ”

“ Moab and Spanish Valley are beyond river, and south end of La Sal Mountains forms distant skyline. (Fig. 25)
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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. ”

“ 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. ”