The Geologic Story of Canyonlands National Park

by Stanley William Lohman

The Needles district

The Needles district is currently (1973) the most highly developed part of the unfinished park as the result of design, not accident, for this district includes the greatest number and widest variety of spectacular features—The Needles proper, The Grabens (pronounced gräbǝns), colossal arches and other erosional forms, large meadows such as Squaw Flat and Chesler and Virginia Parks, a wide variety of prehistoric ruins and pictographs, and Confluence Overlook for viewing the joining of two mighty rivers—the Green and the Colorado. Like the White Rim and The Maze, the Needles district is another of the broad benchlands about midway between the high mesas and the deep canyons.

Utah Highway 211, as mentioned already, is a 38-mile-long paved road leading to the Needles district from U.S. Highway 163 at a point 15 miles north of Monticello and 18 miles south of La Sal Junction. The intersection is well marked by Church Rock ([fig. 37]), a butte of the Entrada Sandstone. Highway 211 gradually climbs an eastward-dipping slope of the Navajo Sandstone dotted with a few buttes and patches of the Entrada Sandstone, such as Church Rock, and reaches the first of two summits 3 miles west of Highway 163. The road crosses a broad gentle valley in the Navajo Sandstone, reaches the second summit about 10 miles from the highway, then descends steeply through the Navajo Sandstone and part of the Kayenta Formation to Indian Creek, 1½ miles below, and follows this creek nearly to The Needles. Half a mile down the canyon takes us to the top of the cliff-forming Wingate Sandstone, and another half mile brings us to Indian Creek State Park and its striking Newspaper Rock ([fig. 5]). Another 1¾ miles takes us to the base of the Wingate and top of the underlying Chinle Formation, which forms the red slope beneath the cliffs.

Historic Dugout Ranch ([p. 14]) is 19 miles west of the highway, and from here a dry-weather road leads southward up north Cottonwood Creek 37 miles to Beef Basin and connects with roads to Elk Ridge and the Bears Ears, both just west of the Abajo Mountains. Just west of the ranch we get a good view ahead of two historic landmarks—North and South Six-Shooter Peaks ([fig. 38]), so named because of their resemblance to a pair of revolvers pointing skyward. The guns are sculptured from slivers of Wingate Sandstone resting upon conical mounds of the Chinle. These can be seen from a wide area; both appear in figures [38] and [40], and the north one is seen in [figure 77].

CHURCH ROCK, standing guard at the intersection of U.S. Highway 163 and the east end of Utah Highway 211 leading to the Needles district. Rock is Entrada Sandstone: red foundation is Dewey Bridge Member; yellowish smooth rounded body of church is Slick Rock Member; white steeple is Moab Member. La Sal Mountains at left. (Fig. 37)

NORTH AND SOUTH SIX-SHOOTER PEAKS, looking west from entrance road to The Needles. (Fig. 38)

A mile west of Dugout Ranch we descend to the top of the Moss Back Member of the Chinle, a ledge of gray-green sandstone forming the base of this generally red formation, and reach the base of the member at the top of the Moenkopi Formation in the next mile and a half. The Moss Back is uranium bearing in nearby areas.

At 3.8 miles west of Dugout Ranch a poorly marked road on the left crosses Indian Creek, then forks; the left-hand fork follows the bed of Lavender Canyon, and the right-hand fork goes into Davis Canyon. Headwaters of both these canyons are new additions to the park.

The red Organ Rock Tongue of the Cutler Formation is seen about 3 miles beyond the turnoff, or about 6 miles west of Dugout Ranch. Another 1½ miles takes us down in the rock column ([fig. 9]) to the top of the Cedar Mesa Sandstone. The White Rim Sandstone, which forms such a prominent bench around the southern part of Island in the Sky (figs. [20]-[23]) and west of the Green River, is missing from the Needles district, its place in the rock column being taken by red shales and sandstones of the Cutler Formation. South of Indian Creek other underlying red beds of the Cutler are gradually replaced in turn by the thick Cedar Mesa Sandstone. Erosion has reduced the general level of the Needles district to or into the Cedar Mesa Sandstone, but many streams have cut into the underlying Rico Formation, and the Colorado River has cut also into, and in places through, the limestones of the unnamed upper member of the Hermosa Formation. Our first view of The Needles is another 4 miles, and 1 more mile takes us to the park boundary, nearly 32 miles from the U.S. Highway 163. We pass a road on the right leading to Canyonlands Resort, and on the left is a new line camp which replaces the restored one at Cave Spring ([fig. 6]).

The unusual features of the Needles district are due in some part to the character and thickness of the underlying rocks but in large part to erosion along joints and faults. Joints are fractures along which no displacement has taken place, and faults are fractures along which there has been displacement of the two sides relative to one another ([fig. 76]). The Cedar Mesa Sandstone comprises 500 to 600 feet or more of hard well-cemented buff, white, and pink beds of massive sandstone. On the basis of the type and amount of deformation and erosion of the Cedar Mesa Sandstone and underlying rocks, the Needles district can be divided into three differing areas: (1) an eastern area where the rocks are relatively undeformed but are carved into an intricate series of canyons, including Salt Canyon and the upper reaches of Davis and Lavender Canyons—the section of the district that contains most of the arches and Indian ruins; (2) The Needles proper, where tensional forces have cracked the brittle Cedar Mesa Sandstone into a crazy-quilt pattern of square to rectangular blocks separated by joints widened by erosion, creating a myriad of spires and pinnacles; and (3) The Grabens, where the previously jointed rocks were later subjected to additional tensional forces that produced a series of nearly parallel faults that trend northeastward and separate downdropped blocks of rock, called grabens, from intervening stationary or upthrown blocks of rock, called horsts.

Let us examine each of these areas in the order named. For traveling to most features a four-wheel-drive vehicle is strongly recommended. Some visitors negotiate the jeep trails with dune buggies or motorcycles, but four-wheel-drive vehicles are considered safer and generally more reliable. A few trails can be traveled only on foot.

Squaw Flat, in the western part of the relatively undeformed area, is a nearly flat area of lower Cedar Mesa Sandstone covered here and there by a thin layer of sparsely vegetated soil and surrounded by generally low hilly erosional forms in the upper part of the sandstone. Short canyons and alcoves in the sandstone hills along the west side afford excellent semi-private campsites, each of which has its own paved access road, picnic table, and trash can ([fig. 39]). Moreover, ground water at shallow depth in the underlying sandstone has encouraged the growth of exceptionally large piñon and juniper trees that provide welcome shade.

SQUAW FLAT CAMPGROUND, in the Needles district, in Cedar Mesa Sandstone. Large piñon and juniper trees draw ground water from this sandstone. (Fig. 39)