bluuebunny/crossref_metadata_2025 huggingface dataset:
The Montini Volcano; A lava dam on the ancestral Snake River, southwest Idaho
Authors: Malde Harold E.
Published: November 2007

The name Montini Volcano is applied to a much-dissected basaltic vent where Sinker Creek joins the canyon of the Snake River southwest of Boise Fig. (1). The name comes from Montini Ranch—now the Nahas Ranch—on the 1949 edition of the Sinker Butte Topographic Quadrangle (1:24,000). The Volcano is also partly with in the adjacent Wild Horse Butte Quadrangle. Downcutting by the Snake River and Sinker Creek has exposed the plug of the volcano and nearly 600 ft (180 m) of its surrounding tuff and lava.

The Montini Volcano can be reached from milepost 33 on Idaho 78 by following the road shown in Figure 1. Just before reaching Sinker Creek, a single-lane track negotiable by passenger cars leads down Sinker Creek to the central plug of the volcano Fig. (2). Although a gate has been installed at the head of the track to control livestock, the track is open to the public. From the plug, the track continues to a pumping station one mi (1.6 km) down the Snake River (NW¼Sec.6,T.3S.,R.l E.). From here, looking upstream, one has a splendid view of the dissected volcano (Fig. 3). Those wanting to see other parts of the Montin Volcano must back track to the Nahas Ranch and ask permission to use the ranch road. From the ranch headquarters, this roadleads southeast and then northeast to a point on the Snake River about 2 mi (3 km) above the mouth of Sinker Creek. A single lane track on the north
The Late Proterozoic Pocatello Formation; A record of continental rifting and glacial marine sedimentation, Portneuf Narrows, southeastern Idaho
Authors: Link Paul Karl
Published: November 2007

Portneuf Narrows is located on the Inkom, Idaho, 1:24,000 Topographic Quadrangle. The area is ideal for a one-day field trip because it is accessible from 1–15 (Exit 63-Portneuf Area) and is only 3 mi (4.8 km) from Pocatello where tourist services and the Idaho State University Library are available. Stops 1 and 3 are on paved roads. Stop 2 is on a dirt road that can be driven by passenger cars in dry weather. The entire area is on public land.

Stop 1 is an overview of Portneuf Narrows (Fig. 1A); it is reached by heading southeast from Pocatello on I–15 and taking exit 63S. Turn west (right) onto the frontage road (South Fifth Avenue), proceed 0.7 mi (1.1 km), cross under the freeway, and stop on the east side of the frontage road. If approaching from the south (Salt Lake City), take exit 63N, turn right at the frontage road, and proceed 0.2 mi (0.3 km) to Stop 1 on the left side of the road.

The outcrops south of Portneuf Narrows (Stop 2) are reached by heading south on Fort Hall Mine Road from exit 63. Cross the Union Pacific Railroad and the Portneuf River and proceed 0.2 mi (0.3 km) to Portneuf Road. Cross it, and continue straight for 0.6 mi (l km). There, bear left onto dirt road (avoiding road to sanitary landfill) and park at locked gate in Fort Hall Mine Canyon (Stop 2, Fig. 1A). The most complete stratigraphic sections can been seen in the base of the second canyon
Heart Mountain detachment fault and elastic dikes offault breccia, and Heart Mountain break-away fault, Wyoming and Montana
Authors: Pierce William G.
Published: November 2007

This text includes two sites: the first is the Heart Mountain detachment fault and elastic dikes of fault breccia (Site 33 in Fig. 1); the second, located 1 mi (2 km)to the west of the first, is a related feature termed the Heart Mountain break-away fault (Site 33 in Fig. 1). If only one site can be examined, Site 33 should be selected: It is more accessible, and has better exposures and more features pertaining to the Heart Mountain fault.

Site 33 (Fig. 1), showing the Heart Mountain detachment fault and elastic dikes, is situated 0.5 mi (0.8 km) due south of Silver Gate, Montana. It can be reached on foot by climbing a steep mountain slope (600-vertical ft (180-m) gain in 1,800 ft (540 m), beginning at the end of the road 1,000 ft (300 m) south of the Post Office. The site is on public land but at the outset 300 ft (100 m) of private land must be crossed when taking the most direct route. The owner of the undeveloped private land does not object to scientists crossing her land to reach Site 33.
Rhyolite-basalt volcanism of the Yellowstone Plateau and hydrothermal activity of Yellowstone National Park, Wyoming
Authors: Christiansen Robert L. , Hutchinson Roderick A.
Published: November 2007

A volcanic plateau constructed by late Pliocene and Quaternary eruptions spans the Continental Divide and occupies the central part of Yellowstone National Park, mainly in northwestern Wyoming but overlapping into eastern Idaho and southwestern Montana. The National Park is accessible by road through five entrances, reached by U.S. 20 from the west and east, from the north and south, and U.S. 212 from the northeast (Fig. 1). The localities described in this guide are all on or adjacent to the park road system and can be reached, during the summer months (usually early May through late October), by passenger car or, during the winter, by skis or skimobile. A nominal entry fee for vehicles is valid in both Yellowstone and Grand Teton national parks.

Special caution should be exercised in visiting the thermal 89 areas; they are both delicate and dangerous. Designated walk-ways are provided in the thermal areas described here, and posted park regulations should be followed. Specimen collecting in the national park is allowed only by permit, which can be issued by the National Park Service only in advance of a collecting trip.
Idaho- Wyoming thrust belt
Authors: Ore H. Thomas , Kopania A. A.
Published: November 2007

This guide describes two areas of observation in the Idaho-Wyoming thrust belt. The first is a 3-mi (4.9-km) long section on Teton Pass, west of Jackson, Wyoming, along Wyoming 22 (Fig. 1). The geologic map (Fig. 2) and discussion below refer to a section that stretches from 2.5 mi (4.0 km) west of the summit of Teton Pass to 0.5 mi (8.0 km) to the east. The area is depicted on the Teton Pass and Rendezvous Peak 7¼-minute Geologic Quadrangle Maps (Schroeder, 1974, 1976). The second area is along the Hoback Valley and Canyon, about 10 mi (16 km) southeast of Jackson. Observations there are along U.S. 187–189, from Hoback Junction to Granite Creek, about 11.5 mi (18.5 km) east. The area is depicted on the Camp Davis and Bull Creek 7¼-minute Geologic Quadrangles (Schroeder, 1974, 1976). Two other locations in the area are briefly described. They are both on U.S. 26–89 in the Grand Canyon on the Snake River. The first is about 3 mi (4.8 km) southwest of Hoback Junction, where the Darby thrust is exposed, the other is at Keyser Creek, about 8 mi (12.9 km) east of Alpine Junction, where the Little Greys Anticline is exposed. All locations described herein are on public land.
Hoback River Canyon, central western Wyoming
Authors: Dorr John A. , Spearing Darwin R. , Steidtmann James R. , Wiltschko David V. , Craddock John P.
Published: November 2007

Geologic features along the Hoback River Canyon in central western Wyoming illustrate tectonic effects and stratigraphic and structural evidence for dating thrusts and later listric normal faults in part of the Idaho-Wyoming Thrust Belt and adjacent Foreland. Figure 1 and Table 1 combine to show that major thrusts in the Thrust Belt young in thedirection of tectonic transport, in this case from west to east, the oldest being the Paris Thrust and the youngest the Prospect. The preeminent features, logged below and visible from the highway (Fig. 2) are, west to east, the Hoback Fault (listric normal), Bear Thrust, Prospect (=Cliff Creek=Jackson) Thrust and Game Hill Thrust. These are capitalized on Table 1.

The site description begins on the west at Hoback Junction, 13 mi (21 Km) south of Jackson, Wyoming, on U.S. 187-189. It follows U.S. 187-189 east from there for 16 mi (26 km) with four stops enroute (Fig. 2). It crosses from south-central Teton County into northwestern Sublette County within U.S. Geological Survey Camp Davis and Bull Creek 7½-minute tomographic and geologic map quadrangles. Small-scale colored geologic map and cross-section sheets, which include the site, are in the pocket at the back of Dorr and others, 1977. A detailed road log of this area is given by Spearing and Steidtmann (1977).
Sandstones of the Casper Formation of the southern Laramie Basin, Wyoming
Authors: Steidtmann James R.
Published: November 2007

Very large scale, trough cross-stratification in sandstone units of the Casper Formation is well exposed along Sand Creek in the southernmost Laramie Basin, Wyoming (Fig. 1). The exposures of features described herein are located in the SW¼, Sec.31, T.13N., R.74W. and the E½, Sec.l, T.12N., R.75W.(Fig. 1). This locality is included in a field trip guide by Steidtmann and Weimer (1976); photographs of the features mentioned herein are in Steidtmann (1974, 1976).
Early Proterozoic and Precambrian-Cambrian unconformities of the Nemo area, Black Hills, South Dakota
Authors: Redden Jack A.
Published: November 2007

Excellent exposures of both an early Proterozoic uncon formity and the Precambrian-Cambrian unconformity occur in the Nemo area along the eastern side of the Precambrian core of the Black Hills approximately 18 mi (30 km) northwest of Rapid City (Fig. 1). Although the two unconformities are exposed relatively near one another, there is approximately 1.5 Ga difference in their ages. The lithologies and structure of these localities permit significant inferences about tectonic events and geologic history of the Black Hills.
Harney Peak Granite and associated pegmatites, Black Hills, South Dakota
Authors: Shearer C. K. , Papike J. J.
Published: November 2007

The Harney Peak Granite is located in the south-central portion of the Precambrian core of the Black Hills, South Dakota. This field study includes five sites near Keystone, South Dakota (Figs. 1 and 2). All sites are accessible by passenger car. At Site 1, the Harney Peak Granite is exposed at the Mount Rushmore National Memorial. (Large groups visiting at Mount Rushmore are expected to check in at the memorial headquarters.) Hammers or sample collecting are not allowed at the Rushmore site. A suite of Harney Peak Granite maybe collected to the west of the memorial (Site la). Sites 2 through 5 are pegmatites (Diamond Mica, Etta, Peerless, and Dan Patch) associated with the Harney Peak Granite. Permission for access to the Etta pegmatite may be obtained from the Pacer Corporation, Box 912, Custer, South Dakota 57730 (605/673-4458). Permission for access to the Peerless pegmatite maybe obtained from the Rushmore Borglum Museum in Keystone, South Dakota (605/666-4449). The other sites are on public land.
Precambrian metamorphic rocks of the Devil’s Gate- Weber Canyon area, northern Utah
Authors: DeCourten Frank L.
Published: November 2007

The site discussed here in is located in the central Wasatch Mountains near the mouth of Weber Canyon, 9 mi (15 km) southeast of Ogden, Utah. Numerous excellent exposures of Precambrian metamorphic and igneous rocks occur in Weber Canyon from approximately Mountain Green, Utah, downstream to the mouth, in an area of roughly 4 mi2 (10.5 km2) (Fig. 1). The area of principal interest is in sections 26 and 36, T.5N., R. 1 W., and in Sec. 28–32, T.5N., R. 1 E. (Salt Lake Meridian). The Devil’s Gate-Weber Canyon locality occupies the southwest comerof the Snow Basin 7½-minute Quadrangle andthe southeast corner of the Ogden, Utah 7½-minute Quadrangle. I-84 bisects the area and offers easy accessto many excellent outcrops.
Green River Formation (Eocene), central Utah
Authors: Baer James L.
Published: November 2007

The Green River Formation is well exposed in roadcuts along U.S. 50–6 in central Utah. This highway is an all-weather road, and provides easy access to these excellent exposures during the normal field season (Fig. 1).
Multiple soils in pre-Wisconsin drift on Mokowan Butte, southwestern Alberta
Authors: Karlstrom Eric T.
Published: November 2007

The stratigraphy and morphology of superposed pre-Wisconsin soils on Flaxville surface remnants (Alden, 1932) east of Waterton-Glacier Park can best be studed at Mokowan Butte (Fig. 1). The site is located on private land about 1.2 mi (1.9 km) east of the Waterton Park boundary and 3.6 mi (5.8 km) north ofthe International Boundary and is reached by driving about 21 mi (33.6 km) west of Cardston, Alberta, on a dirt road. The trip can be completed in a half day with a robust two-wheel or four-wheel drive vehicle. Landowners’ permission is not required.
The House Range, western Utah
Authors: Hintze Lehi F. , Robison Richard A.
Published: November 2007

The House Range is one of the principal ranges in western Utah (Fig. 1). It trends north-south for 60 mi (100 km)along the west edge of the Sevier Desert and lies 40 mi (65 km) west of Delta, Utah. The range has an asymmetric profile Its eastern slopes, formed mostly on dipslopes of Cambrian strata, rise gradually up from the Sevier Desert floor; its western face, formed by block faulting, rises abruptly from the floor of Tule Valley (also known as White Valley) at an elevation of 4,400 ft (1,300 m) to its highest point, Notch Peak, elevation 9,655 ft (2,943 m). The northwest face of Notch Peak forms one of the tallest sheer cliffs in the west.

Delta, an irrigation-farming community situated in the center of the Sevier Desert, is the nearest source of gas, food, and supplies. U.S. 6-50 cuts southwestward from Delta to cross the southern part of the House Range at Skull Rock Pass. Graded gravel roads extend the entire length of the range on either side; roads cross the range only at Skull Rock Pass, at Marjum Pass in the middle, and at Death (Dome) Canyon a few miles north of Marjum Pass.

People planning to visit the House Range should inquire in Delta about road conditions. Although most of the time the main gravel roads are suitable even for passenger cars, after storms these roads may be washed out and passable only with fourwheel-drive vehicles.
Stratigraphy and structure of the San Rafael Reef, Utah; A major monocline of the Colorado Plateau
Authors: Rigby J. Keith
Published: November 2007

Location. The San Rafael Swell is a major domal uplift in the northwestern Colorado Plateau and dominates the structure of east-central Utah. The San Rafael Reef site is on its eastern edge, approximately 13 mi (21 km) west of Green River, in Emery County, Utah (Fig. 1). 1–70 cuts more or less directly across the structure (Rigby and others, 1974).

Accessibility. Roadcuts are on right-of-way controlled by the Utah State Highway Commission. Land along side the route is generally controlled by the U.S. Bureau of Land Management.Alluvial flats along the San Rafael River are on private land.

Significance of Site. The San Rafael Swell is characteristic of many asymmetric large uplifts of the Colorado Plateau; and itseastern margin, the San Rafael Reef, is representative of monocline of the province. A complete stratigraphic sequence from the Permian White Rim-Cedar Mesa Sandstone up through Triassicand Jurassic rocks to the lower part of the Cretaceus Mancos Shale Fig. 2 is exposed along the highway. These rocks accumulated in a wide variety of depositional enviroments, ranging from marine carbonate and elastic environments to deserts(Rigby, 1978).
Moab salt-intruded anticline, east-central Utah
Authors: Baars D. L. , Doelling H. H.
Published: November 2007

Moab, Utah, lies on the northwestern end of the Moab Valley salt-intruded anticline on the banks of the Colorado River in east-central Utah, in T.25 and 26S., R.21 E. (38°36'N.,109°32'W.), on the Moab 15’ Quadrangle, in southern Grand County, Utah (Fig. 1). U.S. 163 passes through Moab and along the length of Moab Valley. The elevation at Moab is 4,000 ft(1,467 m). The area is readily accessible with any vehicle, but off-pavement lands are almost entirely privately owned and permission should be secured for specific locality access.
Kolob Canyons, Utah
Authors: Grant Sheldon Kerry
Published: November 2007

The site encompasses that portion of the Kolob Canyon ssection of Zion National Park, in southwestern Utah, that is visible from the 5-mi-long (8-km) park highway (Fig. 1). The park road is suitable for passenger cars and other vehicles.

Kolob Canyons offer spectacular views of slopes that show the effects of erosion on the thick massive Navajo Sandstone. In addition, exposures in Taylor Creek, LaVerkin Creek, and their tributaries reveal details of stratigraphy and structure. Much of the Mesozoic section is exposed, from the basal Timpoweap Limestone of Early Triassic age to the Jurassic Carmel Formation, inaccessible at the tops of the Navajo cliffs. Structurally, two episodes of tectonic activity’ are evident. The Late Cretaceus Sevier orogeny produced the Kanarra fold, with effects throughout the site. Most interesting perhaps is the Taylor Creek thrust zone, on the eastern limb of this fold. The Late Cenozoic Hurricane fault scarp forms the western boundary of the area, and uplift along this fault set up conditions that led to the erosional phenomena.
Laramide fault blocks and forced folds of the Livermore-Bellvue area, Colorado
Authors: Matthews Vincent
Published: November 2007

Location and Access. Four localities north of Fort Collins, Colorado (Fig. 1) display many of the structural features found throughout the Wyoming province of the Rocky Mountain Foreland. All of the localities can be viewed from public roads that are easily accessible to passenger cars or buses.

Significance of Locality. The northeastern flank of the Front Range displays several varieties of Laramide folds as well as critical relationships for demonstrating that the folds in the sedimentary rocks are forced folds resulting from differential uplift of faulted blocks of Precambrian basement. Within this smallarea are several beautifully exposed monoclines; differentially up-lifted blocks (both tilted and untilted) of Precambrian basement;and well-displayed asymmetrical anticlines, synclines, domes, andbasins. The area is also cut by a major lineament that separatestwo major structural styles in the Front Range and Denver Basin(Matthews, 1976). In this small area, one can see most of the crucial relationships which bear on the controversy over the nature and origin of Laramide deformation in the Rocky Mountain Foreland Province. The sites are described in more detail in Matthews and others (1976), Matthews and Sherman (1976), and Matthews and Work (1978).
Precambrian structure, metamorphic mineral zoning, and igneous rocks in the foothills east of Estes Park, Colorado
Authors: Hutchinson Robert M. , Braddock William A.
Published: November 2007

The area is located in the north-central part of Colorado and is readily accessible via U.S. 34, which roughly divides the area into north and south halves (Fig. 1). The eastern boundary of the area is 8 mi (9 km) west of Loveland, where U.S. 34 enters Big Thompson Canyon. Big Thompson power plant and Little Dam are at the immediate entrance to the canyon. Hard-bottomed dirt roads run north and south from the highway and afford ready access to the eleven stops shown on Figure 1)1.
Paleozoic-Mesozoic section
Authors: Weimer Robert J. , Roy L. W. Le
Published: November 2007

Several significant sections of Paleozoic and Mesozoic rocks occur in close proximity to one another at the foot of the Front Range west of Denver. The Paleozoic section on the east flank of the central Front Range is well exposed in Red Rocks Park. Excellent exposures of the Mesozoic section are at the 1-70 Road Cut, and along Rooney Road, east of the Dakota Hogbak on the southeast side of 1-70.

Location and access. Red Rocks Park is located northwest of Morrison, Colorado, 10 mi (16 km) west of Denver (Fig. 1). The 1-70 Road Cut is located west of Denver, 3 mi (5 km) south of Golden, Colorado, and is the point at which 1-70 cuts the Dakota Hogback. Rooney Road is east of the Dakota Hogback on the southeast side of 1-70. To reach all three sites, proceed west from Denver about 10 mi(16 km) on 1-70. Leave 1-70 at the Morrison Exit, which is well marked. A parking lot and footpath adjacent to the exit provide access to the 1-70 Road Cut site. To reach the Red Reeks and Rooney Road sites, proceed south from the exit on Colorado 26. About 1 mi (1.6 km) south of 1-70, signs at a marked intersection will direct one west to Red Rocks Park, or east to Rooney Road via Colorado 26 (Alameda Parkway). All three localities are on publicly owned lands and can be reached by passenger car. Adequate parking is available at each locality. Generalized lithologies and
The Florissant Fossil Beds National Monument, Teller County, Colorado
Authors: Hutchinson R. M. , Kolm K. E.
Published: November 2007

The Florissant National Monument is easily accessible by taking U.S. 24 west from Colorado Springs to the small town of Florissant, 35 mi (56 km) away (Fig. 1). At the town center, turn south toward Cripple Creek on the unpaved Teller County Road No. 1. The national monument is 0.5 mi (0.8 km) from the town of Florissant. The entire national monument area can be seen in half a day’s time.
The Garden of the Gods and basal Phanerozoic nonconformity in and near Colorado Springs, Colorado
Authors: Noblett Jeffrey B. , Cohen Andrew S. , Leonard Eric M. , Loeffler Bruce M. , Gevirtzman Debra A.
Published: November 2007

The Garden of the Gods, a city park within the Colorado Springs city limits, is located on the eastern flank of the Colorado Front Range (Fig. 1). It can be reached by following the Garden of the Gods Road (exit 146 from I-25) west 2.4 mi (3.8 km) until it curves to the south and becomes 30th Street. Continue south 1.5 mi (2.4 km) to an unnamed road marked by a small sign (Garden of the Gods) and turn right (west) into the park. Mesa Road, which veers uphill from 30th Street 0.8 mi (1.3 km) north of the turnoff to the park, crests at a spectacular overview of the park and surrounding areas. Several U.S. Geological Survey 7½-minute quadrangle maps cover this region. The Garden of the Gods lies mostly within the Pikeview and Cascade Quadrangles; with its southern part in the Colorado Springs and Manitou Springs Quadrangles. The two stops described here are all on public land and can be reached by passenger car.
Grenadier fault block, Coalbank to Molas Passes, southwest Colorado
Authors: Baars D. L. , Ellingson J. A. , Spoelhof R. W.
Published: November 2007

The Grenadier fault block is a paleotectonic complex exposed in the heart of the San Juan Mountains of southwestern Colorado. Structural and stratigraphic complexities are well exposed by the effects of Pleistocene glaciation and Recent erosion at and above timberline in a rugged alpine setting (Fig. 1). U.S 550 traverses the region between Durango and Silverton, affording excellent access. The most critical exposures lie within T.40N., R.7,8W., near the intersection of 37°45’N. and 107°45’ W. in LaPlata and San Juan Counties. Elevations range between 9,000 and 14,000 ft (3,300-5,133 m), effectively limiting field observations to mid-summer months. The area lies within the San Juan National Forest; access is therefore unrestricted. However, due to the rough terrain, appropriate safety precautions should be observed.
San Francisco Mountain
Authors: Helm Richard F.
Published: November 2007

San Francisco Mountain, about 6 mi (10 km) north of Flagstaff, Arizona (Fig. 1), is a composite volcano in the San Francisco volcanic field of northern Arizona; the volcano is situated on the southern Colorado Plateau about 31 mi (50 km) north of the escarpment that forms its topographic edge. Flagstaff, the major city in the volcanic field, is at the junction of 1-40, U.S. 180, and U.S. 89, the latter two highways passing San Francisco Mountain on its west and east sides, respectively. Access to the mountain is by unpaved U.S. Forest Service roads, most of which are passable by low-clearance vehicles; a few primitive roads require 4-wheel-drive vehicles.

A ski resort on the west side of the mountain normally operates its chairlift during the summer months, providing easy access to the 11,600 ft (3,512 m) level on Agassiz Peak. Hiking restrictions are in effect on Agassiz and Humphreys Peaks, and the designation of the upper part of San Francisco Mountain as the Kachina Peaks Wilderness Area imposes wilderness area restrictions. The Inner Basin is reached by foot or with a vehicle permit from the U.S. Forest Service. The Elden Ranger District office in Flagstaff should be consulted in planning a back-country trip.
Ship Rock, New Mexico
Authors: Delaney Paul T.
Published: November 2007

Ship Rock, the erosional remnant of an Oligocene volcanic vent, is a prominent feature of the skyline in northwest New Mexico. It rises 1,700 ft (500 m) above a surrounding plain, 24 mi (38 km) south-southeast of the Four Corners and 10 mi (17 km) southwest of the town of Shiprock.
Upper Cretaceous-Paleocene sequence, northwestern New Mexico
Authors: Kues Barry S. , Lucas Spencer G.
Published: November 2007

The area discussed here is in San Juan County, New Mexico, approximately 30 mi (48 km) south of Farmington and 20 mi(32 km) northwest of Chaco Canyon National Monument (Fig. 1). The small settlement of Bisti is most conveniently reached by traveling south on New Mexico 371 from Farmington or north on New Mexico 57 and New Mexico 371 from Thoreau, which is about 73 mi (117 km) east of Gallup on 1-40. Both of these routesare paved to within a few miles of Bisti. From New Mexico 44 atHuerfano an improved dirt road (County Road 15) runs southwest about 25 mi (40 km) to intersect New Mexico 371 about 9 mi (14 km) south of Bisti.

All of the stops indicated on Figure 1 are accessible by two-wheel drive vehicles, but many of the side roads into the badlands and arroyo areas require four-wheel drive. Viewing of areas off the main roads is best done on foot. The nearest gasoline, food, and water are in Farmington and several stores along New Mexico 44. Most of the area under consideration is within recently established federal wilderness areas, managed by the U.S. Bureau of Land Management (BLM). A few sections are owned by the State of New Mexico or the Navajo Nation, but no part of the area is within the Navajo Reservation. Permission is not required to examine exposures on federal or state land (a permit from the BLMis required to collect fossils), but permission should be obtained from the few
Precambrian-Upper Paleozoic geology along I-40 east of Albuquerque, New Mexico
Authors: Connolly James R. , Kues Barry S.
Published: November 2007

1–40 follows Tijeras Canyon through the Precambrian coreand overlying Pennsylvanian-Lower Permian sequence of the south end of the Sandia Mountains, beginning immediately eastof the Albuquerque city limits. Geologic features of this area are well displayed in road cuts and exposures near 1–40 and are summarized in this text for an 8.6-mi (13.8-km) interval of 1–40, beginning at the eastbound Carnuel (locally pronounced “carnway”) exit (Fig. 1). This section of 1–40 was constructed with wide shoulders, and there are numerous places where, with reasonable care, it is safe to stop along the highway to examine road cuts. Site descriptions, below, progress from west to east(from Precambrian to Permian), but the traveler should be aware that most of the road cuts referred to are on the north side of the interstate highway, along the west-bound lane. To examine them closely, if proceeding eastward, it is necessary to carefully cross the interstate or to drive to a nearby exit and backtrack. Short hikes off the highway, particularly in Precambrian terranes, can be most informative, and old U.S. 66, which parallels 1–40 between Carnuel and Tijeras, provides the safest access for a “hands-on” look at the Precambrian geology. Recent geologic maps of the area considered here were published by Kelley and Northrop (1975); Myers and McKay (1976) and Connolly (1982).
White Sands National Monument, New Mexico
Authors: LeMone David V.
Published: November 2007

White Sands National Monument is located in west-central Otero and east-central Dona Ana Counties in south-central New Mexico (Fig. 1). It is within and bounded by the White Sands Missile Range. The monument has a visitor’s center with the usual facilities. It is open year-round with the single exception of Christmas Day. Summer hours (Memorial Day to Labor Day) are from 8 A.M. to 10 P.M. Winter hours are from 8:30 A.M. to sunset. Periodic trips to Lake Lucero led by monument personnel are planned for every other month. These trips are subject to change depending on weather conditions and the firing schedule at White Sands Missile Range. Information concerning these special trips may be obtained by phoning (505) 437-1058.
Stratigraphy and sedimentology of the Paleocene Fort Union Formation along the Powder River, Montana and Wyoming
Authors: Flores Romeo M.
Published: November 2007

Extensive areas of the Powder River Basin in southeast Montana and northeast Wyoming are underlain by the Paleocene Fort Union Formation (Fig. 1). The sites selected for the field guide (Fig. 1) are easily accessible via the Powder River road from U.S. 212 (Broadus, Montana) to U.S. 14-16 (northeast of Arvada, Wyoming). The Powder River road is a county road that has a hard gravel surface easily traversed by cars. The outcrops are located either immediately along the road or only 0.25 mi (0.4 km) from the road. The lands along the Powder River are either managed by the Bureau of Land Management or privately owned by ranchers, who reserve the right to grant access to these lands. However, numerous field trips sponsored by the American Association of Petroleum Geologists, U.S. Geological Survey, North Dakota Geological Survey, and Casper College have been permitted access to the study sites. Permission was provided with the agreement that field-trip participants respect the land by not littering, not leaving gates open to stock, and carefully observing fire prevention rules. The rancher to contact for sites 1 and 2 is William Gaye, and the rancher for site 3 is Richard Reese. Mr Gaye maintains a ranch house on the Powder River road; Mr. Reese has a residence in the vicinity of Leiter, Wyoming (Fig. 1).
Southern Lemhi Range, east-central Idaho
Authors: Hait M. H.
Published: November 2007

The Lemhi Range, Idaho, is one of three northwest-trending basin-ranges along the northeastern margin of the eastern Snake River Plain (Fig. 1). The southern end of the range is about 55 mi (88 km) northwest of Idaho Falls. The small town of Howe is the closest location for food, water, gasoline, and a trailer park. The nearest motels and service stations are in Arco, about 22 mi(35 km) to the southwest. The area is covered by six 1:24,000 topographic quadrangles. They are listed in the caption of Figure 2A and will be essential for detailed planning of access.

Access to the outcrops is provided by graded dirt roads from Howe to the alluvial apron where rougher roads (traversable by pickups) lead to the seven major canyons in which the stratigraphic sections are exposed (Fig. 2A). From west to east, these canyons are South Creek Canyon, Black Canyon, Middle Canyon, East Canyon, Box Canyon (informal name), an unnamed canyon with a jeep road that crosses the range, and, on the east side of the range, Kyle Canyon.
Silurian Carbonate Mounds, Palisades-Kepler State Park, Iowa
Authors: Witzke Brian J.
Published: November 2007

Silurian strata are exposed at numerous localities ineast-central and northeast Iowa (Fig. 1), where the total Siluriansequence approaches 500 ft (150 m) in thickness. The bulk of thesequence is dominated by dolomite and cherty dolomite characteristically lacking a notable siliciclastic component. The Siluriancarbonates are pervasively dolomitized, except along portions of the northern and northwestern margins of the outcrop belt, where limestones occur. The Silurian early Llandoverian-Ludlovian)dolomite sequence is divided into six formations (Bunker and others, 1985), and a variety of fossil associations characterize the Silurian sequence (Witzke, 1983).

The youngest Silurian rocks in Iowa are exposed in the southern region of the outcrop belt (Fig. 1) and are assigned, in ascending order, to the Scotch Grove and Gower formations. Strata encompassing a part of the Scotch Grove-Gower intervalare well exposed and publicly accessible in the valley of the Cedar River in and around the area of Palisades-Kepler State Park (Fig. 1, about 10 mi (16 km) southeast of downtown Cedar Rapidsand 4 mi (6.5 km) west of Mt. Vernon. The Cedar River has cutthrough Silurian carbonate mound and intermound facies in the area, displaying a series of exposures along forested slopes andbold cliffs, in part overhanging, that form the scenic palisades. The cliffs reach heights to 65 ft (20 m) in places. Hiking trails in the state park provide access to many of the exposures. The most spectacular and instructive exposures encompass localities Athrough F Fig. 1.

The
Cedar Valley Formation of the Coralville Lake area, Iowa
Authors: Bunker Bill J. , Witzke Brian J.
Published: November 2007

Coralville Lake (Fig. 1) was authorized under the Flood Control Act of 1938 as a means of moderating stream flow on the Iowa River. Construction of the dam was begun in 1949, thendelayed by the Korean conflict, and consequently not completed until 1958. Coralville Dam regulates runoff from 3,084 mi2(8,018 km2) of land upstream, providing flood protection to 1,703 mi2 (4,428 km2) of the Iowa River Valley below the dam. The U.S. Army Corps of Engineers maintains Coralville Lake asa multiple-use project providing primary benefits in flood control and low-flow augmentation, and secondary benefits in recreation, fish and wildlife management, forest management, and waterquality improvement. Lake MacBride (Fig. 1) is a subimpoundment of Coralville Lake. The lake and surrounding land compriseLake MacBride State Park, which is managed by he Iowa Conservation Commission.

Exposures along the valley walls of that portion of the IowaRiver which comprises Coralville Lake, afford one the opportunity to examine at numerous points along its extent the upper most portion of the Wapsipinicon Formation and the entire Cedar Valley Formation. Excellent exposures of the Coralville Member of the Cedar Valley Formation can also be seen in the valley walls of the Iowa River in Iowa City (Witzke, 1984a).
Pennsylvanian cyclothem near Winterset, Iowa
Authors: Heckel Philip H.
Published: November 2007

This section is located on the west side of U.S. 169 about 1.7 mi (2.7 km) south of its junction with Iowa 92 on the western outskirts of Winterset (Fig. 1; E line NE¼SW¼Sec.11, T.75N., R.28W., Madison County, Iowa). Because traffic on this highway can be heavy, pull well off onto the shoulder, and please do notcross the highway.
Starrs Cave Park, Burlington area, Des Moines County, southeastern Iowa
Authors: Glenister Brian F. , Kendall Alan C. , Person Jennifer A. , Shaw Alan-B.
Published: November 2007

Starrs Cave Park and Preserve is a facility situated on FlintCreek (Fig. 1) in the northern outskirts of Burlington, DesMoines County, Iowa (W½Sec.19, T.70N., R.2W.). It is administeredby the Des Moines County Conservation Board, Courthouse Burlington, Iowa 52601. Continuous exposures extending from the Late Devonian English River Siltstone through the Early Mississippian (Kinderhookian) carbonates of the North HillGroup and into the Medial Mississippian (Osagean) BurlingtonLimestone extend for 0.5 mi (0.8 km) along the east bank of FlintCreek. At low creek levels, the exposures are accessible directly from the Starrs Cave parking lot, on the west side of Flint Creekoff Irish Ridge Road. A steep foot trail down the cliffs to the eastprovides access from the northern extension of Irish Ridge Road during periods of high water.
House Springs, Missouri, roadcut and fault
Authors: Thompson Thomas L.
Published: November 2007

This section is a roadcut on Missouri 30 approximately 0.5mi (0.8 km) northeast of the junction of Missouri 30 with Jefferson County road MM, the turnoff tothe town of House Springs; SE¼SE¼NE¼Sec.33, T.43N., R.4E., Jefferson County, Missouri, House Springs 7½-section Quadrangle Map (Fig. 1). An excellent exposure of a northwest-trending fault is in the NW½NW½ Sec. 34, T.43N., R.4E.
I-55 roadcuts, Herculaneum-Barnhart, Missouri
Authors: Thompson Thomas L.
Published: November 2007

This is a sequence of roadcuts on I-55, extending from the NW¼ Sec.19, T.41N., R.6E., to the SE¼ Sec.19, T.42N., R.6E. (Fig. 1). These sections are accessible from the frontage road on the west side and from the Interstate highway. All exposures are i the Herculaneum 7½-minute Quadrangle.
Knob Lick Mountain section
Authors: Kisvarsanyi Eva B. , Hebrank Arthur W.
Published: November 2007

Knob Lick Mountain, in the eastern part of the St.Francois Mountains, is about 9.5 mi ( 15.2 km) south of Farmington, in St.Francois County, Missouri (Wachita Mountain 7½-minute Quadrangle). Rising to agentle elevation of 1,333 ft (400 m) above sea level, Knob Lick Mountain may be reached by following Knob Lick Tower Road for 1.1 mi (1.75 km) west of its junction with U.S. 67, just south of the village of Knob Lick (Fig. la), to the parking lot by the lookout tower a top Knob Lick Mountain (NE¼NE¼SE¼, Sec.8, T.34N., R.6E.). A panoramic view of the St. Francois Mountains is afforded from the bald, 100ft (30 m) south of the lookout tower. The intrusive contact of granite with rhyolite is exposed in an abandoned granite quarry, marked on Figure la (SW¼NE¼NE¼, Sec.8, T.34N., R.6E.), about 2,000 ft (600m) northwest from the lookout tower. Access to the quarry is provided by the old ridge road; walk 2,000 ft (600 m) due northwest from the lookout tower on old ridge road, then 200 ft (60 m) due east through the woods to the quarry. Visit of this site involves about a 1.5-hour hike. The site is on public land.
Elephant Rocks
Authors: Kisvarsanyi Eva B. , Hebrank Arthur W.
Published: November 2007

SE¼SE¼NE¼Sec.15, T.34N., R.3E., Elephant Rocks State Park, Iron County, Missouri; Graniteville 7½-minute Quadrangle. Entrance to the park isfrom Missouri RA,0.7 mi (1.2km) west of its junction with Missouri 21 (Fig. 1). From the parking lot, follow marked trail to the lookout point near the top of the hill.The site is on public land.
Baird Mountain Quarry, southwestern Missouri
Authors: Thompson Thomas L.
Published: November 2007

This section is in a quarry on the west side of Baird Mountain, 1.3 mi (2 km) southeast of Table Rock Dam; NW½SW½NW½Sec.26, T.22N., R.22W., Taney County, Missouri, Table Rock Dam 7¼-minute Quadrangle (Fig. 1). It has been designated the type section of the Baird Mountain Limestone Memberof the Northview Formation (Thompson and Fellows, 1970, p. 149).
The Mount Simon Formation at Eau Claire, Wisconsin
Authors: Ostrom M. E.
Published: November 2007

Exposure in bluff of Chippewa River and in hill called Mount Simon in City of Eau Claire (Fig. 1), in the SW½SW½Sec.8, T.27N., R.9W., Eau Claire County (Elk Mound 7÷-minute Quadrangle). Section includes all rock exposed from top of hill called Mount Simon northwest to base of river bluff.
Cambrian stratigraphy at Whitehall, Wisconsin
Authors: Ostrom M. E.
Published: November 2007

Road cuts north of Whitehall on Trempealeau County Highway “D” and 1.7 mi (2.7 km) north of its juncture with Wisconsin 53 in the SW¼, SW¼, Sec.12, T.22N., R.8W., Trempealeau County, on the Pleasantville 7½-minute Topographic Quadrangle, 1973) (Fig. 1).
The Platte River and Todd Valley, near Fremont, Nebraska
Authors: Wayne William J.
Published: November 2007

From a high point on the south side of the Platte Valley, 4.7 mi (7.5 km) west of Fremont (Fig. 1) and 1.8 mi (2.9 km) north of Cedar Bluffs (SE½SE½ Sec.22, T.17N., R.7E.; Fremont West 7¼-minute Quadrangle), one can view the present Platte River and valley as well as look across an abandoned valle segment through which at least part of the Platte River once flowed (Fig. 2). In addition, the south bluffs of the Platte, which have remained cleanly swept exposures of a large partof the Pleistocene record of eastern Nebraska since before 1900, can be seen from across the river in Hormel Park (N edge SW½Sec.34, T.17N., R.8E.) (Fig.3).

To reach the overview point, follow Nebraska 109 north from Wahoo to Cedar Bluffs, go east 0.25 mi (400 m), then north 2 mi (3.2 km) to County Road 2. Turn west 0.1mi (0.2 km) and stop at the top of the slope (Fig. 1). To reach Hormel Park in Fremont, return to Nebraska 109 and turn east 5 mi (8 km). At U.S. 77, turn northfor 1.5 mi (2.5 km), then west 0.4 mi (0.6km). Follow the gravel road to the southwest about 0.2 mi (0.3 km)to Hormel Park. Drive about 0.2 mi (0.3 km) farther, park, and walk to the edge of the Platte River. Field glasses are useful to examine the bluffs, which are across the river, about 600 ft(200 m) away.

Both the overview point
St. Lawrence and Jordan formations (Upper Cambrian) south of Arcadia, Wisconsin
Authors: Ostrom M. E.
Published: November 2007

Composite section from outcrops and quarries located along Wisconsin 93 (Fig. 1) and extending from 1.8 mi (2.9 km) to 3.5 mi (5.6 km) south of its intersection in Arcadia with Wisconsin 95, in the W¼, NW¼, Sec. 9, T.20N., R.9W., Trempeauleau County (Tamarack 7½-minute Quadrangle, 1973).
Cyclothems in the Carbondale Formation (Pennsylvanian: Desmoinesian Series) of La Salle County, Illinois
Authors: Trask C. Brian
Published: November 2007

The site is located in Sec.8, T.32N., R.2E., La Salle County, Illinois (Fig. 1), on the south bank of the Vermilion River,0.5 mi(0.8 km) west (downstream) of the town of Lowell (Fig. 2). It isin the Margery C. Carlson Nature Preserve owned by the Illinois Department of Conservation. Groups of more than 25 peopleshould check with the site superintendent at Starved Rock StatePark before entering the Preserve. For photographic purposes, thesite can be viewed from the opposite bank, which is ccessiblethrough abandoned clay pits owned by Roy Alleman, Jr. (VillageInn, Tonics, Illinois, 815-442-3535).
Ordovician-Silurian unconformity at Kankakee River State Park, Illinois
Authors: Mikulic Donald G. , Kluessendorf Joanne
Published: November 2007

Upper Ordovician and Silurian rocks are well exposed in aseries of natural outcrops along the Kankakee River from Wilmingtonto Kankakee, Illinois. Some of the best exposures occurin Kankakee River State Park, which extends northwest from the town of Altorf for about 6 mi (9.6 km) (Fig. 1). Thre sites are particularly interesting (Fig. 2).

1. Chippewa Campground—a river bluff on the north sideof the river just below the campground (NW¼NE¼SE¼, Sec.36, T.32N., R.10E., Bonfield 7½ minute Quadrangle, WillCounty).

2. Cowan’s Quarry—abandoned stone pits and river bluffson the north side of the river between the river and State Highwa102 (SE½SW½NW½, Sec.26, T.32N., R.10E, Bon field 7½-minute Quadrangle, Will County).

3. Rock Creek—a canyon of a tributary north of the KankakeeRiver, north and south of the bridge on State Highway 102(S¼SE¼SW¼, Sec.32, T.32N., R.11E., Bourbonnais 7½-minuteQuadrangle, Kankakee County).

All localities except Cowan’s Quarry are accessible by passenger car and are a short walk from a highway or parking lot.Cowan’s Quarry is reached by an unmarked and unmaintaineddirt road leading south to the river from Illinois 102 (Fig. 2). This road is generally in poor condition, but is the only place to park as there is no shoulder on the highway. From the dirt road, walkwest about 300 ft (100 m) along the top of the river bluff to theold stone pits.
Valmeyer Anticline of Monroe County, Illinois
Authors: Norby Rodney D.
Published: November 2007

Strata of the Valmeyer Anticline are exposed in road anstream cuts along Illinois 156 (Fig. 1), which passes throughDennis Hollow from the east edge of Valmeyer to 1.5 mi (2.4km) east of Valmeyer, Monroe County (Sec.2, SE¼SE¼Sc.3, and N½Sec.10, T.3S., R.11W.; Valmeyer 7.5-minute Quadrangle);they are also exposed in the bluff face at Columbia QuarryPlant No. 3, which is 0.9 mi (1.5 km) north of Valmeyer(SE¼NW¼Sec.3, T.3S., R.11W.). The outcrops along Illinois 156are easily accessible with no more than a 300 ft (100 m) walkfrom the highway. Automobile parking is limited to a few widegrassy pullouts adjacent to the south side of the highway andalong driveways of property owners. The area north of Illinois156 has several owners; therefore permission to enter should beobtained from residents nearest a particular outcrop.
Horseshoe Quarry, Shawneetown Fault Zone, Illinois
Authors: Nelson W.John
Published: November 2007

The Horseshoe quarry is located in the SW¼, NW¼, NE¼, Sec.36, T.9S., R.7E., Saline County; Rudement and Equality 7½-minute QuadrangleIllinois (Figs. 1, 2). From Equality, travel south 2.0 mi (3.2 km) via county road to the foot of Wildcat Hills, then west 2.5 mi (4 km) on gravel road to a point 0.2 mi (0.3 km) past the turnoff to Glen O. JonesLake. The longabandoned quarry is in low, wooded hills immediately north of the road, on land administeredby the U.S. Forest Service.
The Cache Valley of southern Illinois
Authors: Masters John M. , Reinertsen Davis L.
Published: November 2007

The Cache Valley in extreme southern Illinois is amajor physiographic feature that extends across all or parts of Pope, Massac, Johnson, Union, Pulaski, and Alexander counties, from the Ohio River on the east to the Mississippi River on the west, and cuts across all or parts of the following Third Principal Meridan townships (Fig. 1): T.13S., R.3, 5, and 63; T.14S., R.1, 2, 3, 4, 5, and 6E, R.1 and 2W; T.15S., R.1, 2, 3, and 4E., R.1, 2, and 3W;T.16S., R.1, 2, 3, and 4W; and T.17S., R.1 and 2W.
Devonian shelf-basin, Michigan Basin, Alpena, Michigan
Authors: Gutschick Raymond C.
Published: November 2007

This chapter cites two localities, Paxton Quarry and Partridge Point (Fig. 1), and combines field observations fromboth to illustrate important stratigraphic relations and principles.Focus is on litho- and biostratigraphyof Middle and Late Devonian rocks as they relate to the Michigan Basin (Fig. 2).

Black organic-rich shales deserve our attention due to their energy potential asource rocks and fracture reservoirs for petroleum and natural gas. The Paxton Quarry offers the opportunity to examine an exceptional exposure of black shale (large area in Fig. 3; thick section in Fig. 4) as part of the formational sheet that continues into the Michigan Basin subsurface. These special rocks offer achallenge to observe and test their physical, chemical, and organic composition and structureto decipher origin, paleoenvironments, diagenesis, history, and economic value. A spectacular display of numerous, largecalcareous concretions, in situ and free of shale matrix, is present in the quarry. How werethey formed?

Partridge Point has an exposed limestone sequence that underlies Antrim black shales beneath Squaw Bay. Applying Walther’s Law, one can go up section and down dip from fossiliferous shallow-water oxygenated Middle Devonian carbonate platform rocks at the shelf marginof the Michigan Basin into Upper Devonian transitional deeper water oxygen-deficient pelagic limestones followed by deep-wateranaerobic black shales of a euxinic basin.
Mississippian Marshall Formation of the Pointe Aux Barques region, eastern Michigan
Authors: Milstein Randall L.
Published: November 2007

Pointe aux Barques Region T.18N., R.1lE. and T.19N., R.13E., Huron County, Michigan; Rush Lake, Port Austin West, Port Austin East, and Kinde West, Michigan, 7½-minute quadrangles.The Pointe aux Barques region ofHuron County extends east from Little Oak Point 18 mi(29 km) along the Lake Huron shoreline to Grindstone City (Fig.1).The Pointe aux Barques area is reachedby following Michigan 53 north from Bad Axe to Port Austin. This picturesque shoreline region is also accessible by boat.