bluuebunny/crossref_metadata_2025 huggingface dataset:
Shoshone Falls, Idaho; A Pleistocene relic of the catastrophic Bonneville Flood
Authors: Malde Harold E.
Published: November 2007

Shoshone Falls is on the Snake River about 4 mi (6 km) northeast of the city of Twin Falls, near the midpoint of a chaotically eroded 14-mi (22-km) section of the Snake River canyon (Fig. 1). The south side of the falls, where the city maintains apicnic ground and park, offers the best views. Westbound travelers on I–84 should take the Kimberly-Twin Falls exit (no. 182), cross the Snake River on the Hansen Bridge, drive 5 mi (8 km) west on Addison Avenue, and then follow the signs northward to the falls. Those traveling east should take the Twin Falls exit at U.S. 93 (no. 173), cross the Snake River on the Perrine Memorial Bridge, and drive 3 mi (5 km) east on Falls Avenue to the Shoshone Falls road. Viewpoints on the south rim of the canyon at both bridges are convenient stopping places to see the narrow canyon above the falls and the wide canyon enlarged by flood erosion downstream. The north side of the falls can be reached by an improved road leading from U.S. 93.
Evidence for the spillover of Lake Bonneville, southeastern Idaho
Authors: Bright Robert C. , Ore H. Thomas
Published: November 2007

The area described herein is in southeastern Idaho, in Franklin and Bannock counties. It is readily reached via I–15 and various paved state highways from any direction.

Each stop is easily accessible by two-wheel drive vehicles when roads are dry. However, the dirt roads leading to stops 1 to 6 can be extremely slick when soaked. Permission from property owners is required if you desire to wander beyond each stop.

The tour is keyed to the following 7½-minute quadrangles: Pocatello North, Inkom, Arimo, McCammon, Bonneville Peak, Downey West, Downey East, Oxford, and Swan Lake. The latter two are particularly important for locating features south of the overflow site. The Preston and Pocatello 2-degree quadrangles are also suggested.

The trip will take about six hours. It begins in northern Cache Valley at the hamlet of Oxford, proceeds northward through Red Rock Pass and Marsh Valley, and ends in the Pocatello area (Fig. 1). Food and lodging can be found in Preston (dry) and Pocatello.
Geology and evolution of the Grand Canyon of the Yellowstone, Yellowstone National Park, Wyoming
Authors: Richmond Gerald M.
Published: November 2007

The Grand Canyon of the Yellowstone is in east-central Yellowstone National Park. It is accessible from Canyon Village (Fig. 1, inset), where all facilities are available. Check in at the visitor center.

Observe park regulations stay on established trails unless you have off-trail permission; do not break rocks or hot-spring deposits; take no samples, not even loose pieces (collecting is not permitted); leave hammers, picks, and shovels in your vehicle. Suggested time: one full day.
The Rhodes allochthon of the Enos Creek-Owl Creek Debris-Avalanche, northwestern Wyoming
Authors: Bown Thomas M. , Love J. David
Published: November 2007

SE¼SE¼NE¼SW¼ Sec.17, NE¼NE¼SE¼SW¼ Sec.17, W¾N½SW¼SE¼ Sec.17, and W¾S½NW¼SE¼ Sec. 17, T.44N., R.99W., Hot Springs County, Wyoming (Fig. 1; Bown, 1982a, PI. 1). Twentyone Creek, Wyoming, Quadrangle (U.S. Geological Survey 7½ minute topographic series, 1956).
Zone of interaction between Laurentide and Rocky Mountain glaciers east of Waterton-Glacier Park, northwestern Montana and south western Alberta
Authors: Karlstrom Eric T.
Published: November 2007

The evidence for interaction between Laurentide and Rocky Mountain glaciers east of Waterton-Glacier Park can best be studied by examining a number of sites in the zone of glacier overlap and possible confluence. The 10 stops described in this field guide are located in the Saint Mary, Belly, and Waterton drainages in Montana and Alberta (Fig. 1). With the exceptions of Stops 1 and 10, which occur on the Blackfeet Indin Reservation and in Waterton Park, respectively, all stops occur on public roads through private land. Landowner’s permission is not required for the excursion as described but should be obtaine before collecting samples or extensive off-route exploration. The trip can be completed in a long half day with two-wheel drive vehicle. Those with less time may limit their trip to Stops 1 through 5 on the U.S. side or the approximately equivalent Stops 6 through 10 in Canada. The U.S. portion of the trip is covered by the Cutbank 1:250,000 topographic sheet and the Saint Mary, Babb, Duck Lake, Wetzel, Hall Coulee, Emigrant Gap, and Pike Lake 1:24,000 sheets. The Canadian portion is covered by the Lethbridge 1:250,000 sheet and the Cardston and Waterton Lakes (82 H/3 and H/4) 1:50,000 sheets.
Wind River Canyon, Wyoming
Authors: Maughan Edwin K.
Published: November 2007

The Wind River Canyon transects the Owl Creek Mountains near the center of Wyoming. The canyon is in the northwest quadrant of the state (Fig. 1) and within the northeast corner of the Wind River Indian Reservation. U.S. 20 traverses the canyon from a point about 15 mi (24 km) north of the town of Shoshoni in the Wind River Basin to the mouth of the canyon about 5 mi (8 km) south of Thermopolis in the Bighorn Basin. The Wyoming Geological Association and the State Highway Department have erected signs that label the geological formations within the canyon; many of the features that will be noted are referenced to mileposts along the highway.
Type Pinedale Till in the Fremont Lake area, Wind River Range, Wyoming
Authors: Richmond Gerald M.
Published: November 2007

The Fremont Lake area is at the southwest base of the Wind River Range, northeast of the town of Pinedale in Sublette County, Wyoming, (Fig. 1). It is included in the Fremont Lake South Quadrangle (scale 1:24,000) for which a topographic map, a geologic map (Richmond, 1973), and a soils map (Sorenson, 1986) are available.

The area is accessible from Pinedale on U.S. 191, about 100 mi (160 km) north of Rock Springs and 70 mi (112 km) southeast of Jackson. County Road 23-111 (paved) leads northeast from Pinedale into the area. Most of the terrain is in Bridger National Forest, but some is private land. All maintained roads are accessible by passenger car. Many unimproved roads require four-wheel drive. Obtain permission to enter gated roads. Respect signs; close all gates unless found open; and do not drive into areas under irrigation.

For a short tour, take County Road 23-11 f from the east end of Main Street in Pinedale toward Fremont Lake. The road leads up a terrace front, passes a cemetery, and extends northeast across gently rolling Bull Lake end moraines to an S-curve 2.2 mi (3.5 km) from U.S. 191. Here, the road ascends the steep, very bouldery front of the outermost Pinedale end moraine. Park at the bottom and walk 50 yd (46 m) up the road to a cut where Pinedale Till is well exposed (locality A, Fig. 1). Drive on to the moraine crest, from which an out standing overview of Fremont Lake, the enclosing Pinedale
Tertiary subsurface solution versus Paleozoic karst solution, Guernsey, Wyoming
Authors: Bridges L.W. (Dan)
Published: November 2007

Guernsey is located in southeastern Wyoming on the Hartville Uplift between Torrington and Douglas on U.S. 26.Guernsey State Park, which is 1 mi (1.6 km) north of U.S. 26, has an average elevation of 4500 ft (1400 m). It is readily accessible by car or bus anytime of the year because this is one of the warmest parts of Wyoming. Most of the outcrops are located in Guernsey State Park, which is in the Guernsey Reservoir quadrangle, Platte County, Sec.4, T.27N., R.66W., approximately 42°17'N,104°46'W.

Key locations to examine the problem of the nature of the solution surface on the top of the Guernsey Limestone are shown on Figure 1. An excellent view of the principal locality (B) (Fig. 2) on the east side of the North Platte River can be obtained from area A on the west side. The paleo-sinkhole at the south end of the exposure, and the solution surface to the north can be reached for closer examination by means of arduous hikes from parking lot C.

To reach the sinkhole area, walk southeasterly from the parking lot on the maintenance road, through the maintenance yards, down into a tributary valley and south along the river.

To see several 3 to 5 ft (1 to 1.5 m) solution arches, and a chert breccia (Fig. 3), on the solution surface, walk from the parking lot down to the top of the Guernsey Limestone and southward along this unconformity. Hiking here should be done with care because
Dunes of the Wyoming Wind Corridor, southern Wyoming
Authors: Marrs Ronald W. , Kolm Kenneth E. , Gaylord David R.
Published: November 2007

This geological field site, notorious for strong, persistent, unidirectional winds that have created classic eolian landforms, is located in the SW¼ Sec.30, T.25N., R.84W., Carbon County, Wyoming (Figs.1), 1,). The area is readily accessible via paved road by traveling north from the town of Sinclair, Wyoming, a distanceof 30 mi (48 km) on the Seminoe Road. This highway is the main access route to Seminoe State Park. The locale is on public land, administered by the Bureau of Land Management, but it borders on private ranch land to the north and state-owned land to the west.

The area is within the broad, windswept zone of central Wyoming (Fig. 1) known as the Wyoming Wind Corridor(Marrs and Kolm, Kolm 1982). The large active dunes at this site and older stabilized dunes in the area are part of the Seminoe Dune Field (Fig. 1) 2). Most dunes in the area are marginally stabilized parabolic dunes. The few active dunes are relatively large and slow moving with active fronts and partially stabilized tails.
The White River Badlands of South Dakota
Authors: Martin James E.
Published: November 2007

One of the most famous and spectacular Tertiary deposits in North America is the White River Badlands. The colorfully banded, fossiliferous, highly dissected landscapes are exposed across much of southwestern South Dakota; a specific landmark is difficult to designate. Most visitors to the Badlands traverse the area in the Badlands National Park between the towns of Interior and Wall in Pennington and Jackson Counties (Fig. 1). Most geological features may be viewed along South Dakota 240, the Badlands Loop; therefore this area has been designated a landmark. Geology is well-exposed along the route at such localities (Fig. 1) as the Pinnacles, Yellow Mounds, Rainbow Overlook, Banded Buttes Overlook, and Cedar Pass. Due to space limitations herein, frequent references are made to the road log, photographs, and bibliographic references of the area by Martin (1985).
Metamorphic, igneous, and sedimentary relationships on the Sioux Quartzite Ridge, South Dakota
Authors: Bretz Richard F.
Published: November 2007

The Sioux Quartzite Ridge geological site consists of three stops east and northeast of Sioux Falls, Minnehaha County, South Dakota, on the Sioux Falls 1° × 2° topographic map (Fig. 1). Sioux Falls is the starting point for a visit to these stops, which are east of the city on 1–90. All of the stops are on allweather roads, and can be reached by large groups traveling by bus. These stops are included in a longer field trip guide (Brenner and others, 1981), which contains more detail and further references.

Stop 1, the 1–90 section, is about 0.5 mi (0.8 km) east of the Corson-Brandon interchange, where the Interstate crosses Split Rock Creek (NE¼NE¼SW¼Sec.26, T.102N., R.48W.; Brandon 7½-minute Quadrangle). Since parking is not allowed on the interstate highway, park at the interchange and walk to the exposures, which occur both north and south of the highway. The outcrops are on private land owned by Howard R. Johnson, Corson, South Dakota 57019, telephone (605) 582–3898.

To reach the second stop, proceed 3.5 mi (5.7 km) to Exit 410 leave 1–90, turn left (north) onto the county road. Travel 5.8 mi (9.5 km) north and turn left (west) onto a gravel road. Proceed for 1 mi (1.6 km) and turn left (south), following signs to Palisades State Park. Drive 0.1 mi (0.2 km) farther and turn right (west) onto the road that leads into the state park.

Stop 2. Palisades State Park is publicly-owned land, so access is unlimited. A
The Book Cliffs Cretaceous section
Authors: Rigby J. Keith , Russon Michael P. , Carroll Richard E.
Published: November 2007

Location and Access. A classic cross section through Cretaceous and early Tertiary rocks is well exposed along U.S. 50-6 in Price Canyon, a gorge cut through the Book Cliffs of eastern Utah (Fig. 1). Price Canyon occurs, in part, on the Helper, Standardville, and Kyune 7½-minute Quadrangles, in northern Carbon County and southeastern Utah County.

Most significant outcrops are readily available along the highway on land controlled by the Utah State Highway Commission. Land beyond the right-of-way is privately owned in the lower part of the canyon, from Castlegate southward, but above Castlegate it is controlled by the Bureau of Land Management.

Significance. Roadside exposures up Price Canyon provide an almost totally exposed section from the middle of the Late Cretaceous Mancos Shale up to the Paleocene-Eocene Flagstaff and Colton Formations (Fig. 2). These outcrops show threedimensional relationships of open marine, deltaic and piedmont systems of the western margin of the Cretaceus Interior Seaway. The section provides excellent models for interpreting deposition in such environments and records a generally regressive elastic sequence. Relationships of major coal accumulation to these depositional environments are also clearly exposed in and near Price Canyon.

Previous Work. Geologic investigation in the area began more than 80 years ago. Numerous reports that concern the area are listed in Cross et al. (1975); Balsley ( 1982); Fouch and others(1983); and Russon (1986). Fouch and others (1983) summarized regional patterns of deposition of Late Cretaceusrocks of
Exceptionally fossiliferous Lower Ordovician strata in the Ibex area, western Millard County, Utah
Authors: Hintze Lehi F.
Published: November 2007

Exposures of the most richly fossiliferous Lower Ordovician strata in the United States occur about 50 mi (80 km) west of Delta, Utah, and extend over an area 6 by 8 mi(15 by 20 km). These rocks form low-lying hills in the southern part of the House and Confusion ranges (Fig. 1) and are reached by paved U.S. 6–50, which passes along the northern edge of the Ibex area, named for a small ranch abandoned in the 1930s. The area is neither populated nor fenced and isused primarily for winter sheep grazing under administration of the U.S. Bureau of Land zones useful to Ordovician students throughout the world. Management, which maintains graded dirt roads that lead to within easy walking distance of most outcrops. There is no water.
The geology of Salina Canyon, Utah
Authors: Lawton Timothy F. , Willis Grant C.
Published: November 2007

The spectacular exposures in the lower part of Salina Canyon(Figs. 1, 2) lie in the Basin and Range to Colorado Plateau transition zone to the east of thrust-faulted Paleozoic rocks in the Pavant and Canyon ranges. The stratigraphic and structural relations exposed along a 4-mi (6.5-km) east-west corridor here provide unsurpassed insight into the late Mesozoic to middle Tertiary geologic history of central Utah. A well-exposed Middle Jurassic to Upper Cretaceus sedimentary section is unconformably overlain by one of the most complete lower Tertiary sequences found in this part of the state.

The site can be reached by following old U.S. 50 (called the “frontage road” in this text) from Salina or from the Gooseberry Valley exit off 1–70 east of the site (Fig. 1, inset). Examination of the area requires two short hikes, one of about 1 mi (1.6 km) round trip (depending upon your vehicle) and one of 2.5 mi(4.0 km).
Late Paleozoic-Mesozoic stratigraphy, Hite region, Utah
Authors: Baars D. L.
Published: November 2007

Present-day Hite, Utah, is on the east bank of Lake Powel in the Glen Canyon National Recreation Area of southeastern Utah (Fig. 1F). It is in T.33 S., R. 14 E., on the Browns Rim 15-minute Quadrangle, San Juan County, Utah. Hite Crossing bridge over the Colorado River extension of Lake Powell ( Fig. 2)is about 75 mi (120 km) west of Blanding, Utah, and 48 mi (77km) southeast of Hanksville, Utah, along Utah 95. The present site of Hite, relocated when Lake Powell flooded the Colorado River canyons, is at about 3,960 ft (1,200 m) near the mouths of White Canyon, entering the Colorado River from the southeast, and the Dirty Devil River and North Wash, entering from the northwest. Access is best shown on the Hite Crossing 1:100,000 map. The area is readily accessible via Utah 95 and is entirely on public lands, either Glen Canyon National Recreation Area or Bureau of Land Management administered lands.
The Milk River Canyon, Alberta
Authors: Beaty C. B. , Barendregt R. W.
Published: November 2007

The Milk River Canyon is located in southeastern Alberta some 62 mi (100 km) east of the town of Coutts (Fig. 1). Access to a valley overlook by passenger caron paved and unpaved county roads is relatively easy and requires no permissions to cross private land, but the easternmost unpaved section of road (beyond Black Butte, Fig. 2 is to be avoided if wet. The canyon itself is not visible until the overlook on its rim is reached. The map (Fig. 2 shows readily recognizable points on the route from Coutts and indicates distances between conspicuous landmarks. As is customary, barbed wire gates, if encountered, should be left as found: open if open, closed if closed. There are no services available east of Coutts, so gas tanks should be comfortably filled.
Beaver Dam Mountains
Authors: Baer James L.
Published: November 2007

The Beaver Dam Mountains are located in the southwest corner of Utah about 18 mi (30 km) west of St. George (Fig. 1). The range is bisected by U.S. 91 and has well-maintained, graded roads suitable for passenger cars along the eastern side of the range.
Tertiary mineralization—Idaho Springs, Colorado
Authors: Budge S. , LeAnderson P. J. , Holden G. S.
Published: November 2007

As 1–70 climbs westward from Denver to the Continental Divide, it traverses the Idaho Springs, Central City, Empire, Georgetown, and Silver Plume mining districts, which lie near the northeast end of the Colorado Mineral Belt. Together these districts comprise a zone of nearly continuous mineralization extending about 16 mi (27 km) east-northeast from Silver Plume to Central City. Originally gold, then later Ag, Cu, Pb, Zn, and U were produced from the area, beginning in 1859. Most mines at present are inactive. Primary precious-metal production was dominated by gold, with some silver, from the Idaho Springs and Central City districts to the northeast and mainly by silver from the Silver Plume and Georgetown Districts to the southwest.Mineralization was associated with shallow Tertiary igneous activity in country rockcomposed of Precambrian (middle Proterozoic) granite and gneiss.

The Idaho Springs site is one of the few easily accessible locations where the Tertiary intrusive suite and mineralization are well exposed on the surface. The site is a road cut along the north side of 1–70, just west of Idaho Springs (Fig. 1). A sketch, drawn to scale, is provided to show the features that may be observed (Fig. 2) 2). Access to the outcrop is along a 20-ft (6-m) wide service road protected from 1–70 by a guardrail.
The Black Canyon of the Gunnison, Colorado
Authors: Hansen Wallace R.
Published: November 2007

The Black Canyon in southwestern Colorado is easily reached by passenger car from U.S. 50 (Fig. 1). Turn north 8 mi (13 km) east of Montrose, Colorado, to reach Black Canyon of the Gunnison National Monument in the most impressive part of the canyon. The National Monument boundary is 5 mi (8 km)from the turnoff, and the approach is very scenic. A key visitation point in the monument is Chasm View overlook. Most visitors will want to see several other points also. Some parts of thecanyon are accessible only by 4-wheel-drive trails or footpaths.
The carbonatite complex at Iron Hill, Powderhorn district, Gunnison County, Colorado
Authors: Armbrustmacher Theodore J. , Shannon Spencer S.
Published: November 2007

The carbonatite complex at Iron Hill is located southeast of the town of Powderhorn along Cebolla Creek, Deldorado Creek, and Beaver Creek in Gunnison County, Colorado. To reach the complex, travel 9 mi (14.5 km)west of Gunnison on U.S. 50 to the intersection with Colorado 149, turn south on Colorado 149 and travel 15 mi (24 km) to the intersection with Cebolla Creekroad; turn southeast on Cebolla Creek road; after about 2.5 mi (4km), the outcrops on the left are in the carbonatite stock of the Present address: Department of Geology, Adams State College, Alamosa, Colorado 81102 complex. Roads to the east off Cebolla Creek road along Deldorado Creek and Beaver Creek connect with a variety of dirt ranch roads that provide excellent access to the rocks of the complex.These roads are periodically maintained by Humphreys Mineral Industries, Inc., of Denver, Colorado, the property managers.Therefore, most of the complex is easily accessible by short hikes from roads navigable by most vehicles. A number of patented mining claims exist in the area, but permission to access the property has never been denied. The geologic map of the complex(Fig. 1) is located within the Rudolph Hill Quadrangle(Olson, 1974) and within the Powderhorn Quadrangle (Hedlund and Olson, 1975).Access roads are also shown on the Rudolph 325 Hill and Powderhorn 7.5-minute quadrangles (1:24,000). Some of the better localities at which to see specific rock exposures are shown on Figure 1.
Multiple catastrophic drainage of Glacial Lake Missoula, Montana
Authors: Alt David D.
Published: November 2007

The lake-drainage site is in Sanders County, Montana, approximately 65 mi (105 km) northwest of Missoula, and about the same distance southwest of Kalispell (Fig. 1).

Paved, two-lane highways and easily passable side roads provide interconnecting access to most parts of the area at all seasons. Montana 382 between Perma and its junction with Montana 28 passes through Markle Pass and across the giant ripples of Camas Prairie. An unpaved track leads from that road to Wills Creek Pass and the Schmitz Lakes. Montana 28 between Plains and Hot Springs crosses the debris fill in the valley of Boyer Creek, and passes Rainbow Lake and through Duck Pond Pass above its head. An unpaved county road connects Rainbow Lake and Camas Prairie.

Ownership is a mixture of private ranch land, public and private forest land, and Flathead-Salish tribal lands, none of which are posted. Access is generally open to all parts of the area except that people planning to spend significant amounts of time on the tribal lands around Rainbow Lake should buy a recreation permit.

The varve site comprises large roadcuts through stream and glacial lake deposits on and near 1-90 in the vicinity of the Nine-mile Exit, about 19 mi (31 km) west of Missoula, in Missoula County (Fig. 1).
Paradox Valley, Colorado; A collapsed salt anticline
Authors: Chenoweth William L.
Published: November 2007

Paradox Valley is located in west-central Colorado, in western Montrose County (Fig. 1). The valley is approximately 23 mi (37 km) long and averages 3 mi (5 km) in width. It occupies a large part of T.46N., R.17W.;T.47N., R.18 and 19W.; and T.48N., R. 19W. Colorado 90 traverses the valley for nearly its full length. This highway begins at Vancorum, which is on Colorado 141 about 2 mi (3 km) west of Naturita, Colorado. Naturita, the largest settlement in the area, is about 100 mi ( 161 km) south of Grand Junction, Colorado, on Colorado 141. After leaving the northwest end of Par Utah. Paradox and Bedrock, Colorado, are the only settlements in the valley.

County roads (marked with signs) provide access to the rims of the valley as well as the canyon of the Dolores River on both sides of the valley. Molenaar and others (1981, p. 7–9) give a detailed road log of the valley.

The majority of land in the Paradox Valley area is in the public domain, administered by the Bureau of Land Management. West oprivate land, owned by ranchers in Paradox. About 15 percent of the valley floor east of the river is privately owned. The vallems are all public domain, with the exception of numerous patented mining claims.
Recurrent Quaternary normal faulting at Major Creek, Colorado
Authors: McCalpin James P.
Published: November 2007

A well-preserved fault scarp resulting from recurrent Quarternary normal faulting occurs at the western edge of the northern Sangre de Cristo Mountains of south-central Colorado, at the mouth of west-draining Major Creek (Fig. 1). The site is approximately 56 mi (90 km) north-northeast of Alamosa, Colorado, and may be approached from Colorado 17 between Alamosa and Poncha Springs, Colorado. Turn east off of Colorado 17, 50 mi (80 km) north of Alamosa, opposite the junction with U.S. 285, onto a dirt road that leads due east for 6 mi (10 km) across the valley floor toward Valley View Hot Springs. Instead of turning off to the hot springs, bear right and follow the road as it turns south to parallel the range front. The road will continue south past the mouth of Garner Creek [1 mi (1.7 km) south of the hot springs turnoff] to the upper part of the Major Creek alluvial fan [2 mi (3.2 km) south of the hot springs turnoff]. Approximately 0.25 mi (400 m) north of the crossing of Major Creek (Fig. 2) turn onto a dirt driveway leading due east to the head of the fan where the fault scarps occur. Entry through the locked gate will require permission from the landowner on the north side of the fanhead, Dr. Ben Eismann, Dept. of Surgery, University of Colorado Health Science Center, Denver, CO 80262. The fault scarps on the south side of the road (including the 1980 trench site, Profile 35 on Fig.
Alteration zones related to igneous activity, Spanish Peaks area, Las Animas and Huerfano counties, Colorado
Authors: Hutchinson Robert M. , Vine J. D.
Published: November 2007

The Spanish Peaks area is composed of two prominent peaks and associated dike swarms about 19 to 22 mi (30 to 35 km) southwest of Walsenburg in south-central Colorado(Fig. 1). Although the entire area is surrounded by roads, the Apishapa Pass road on the south flank of the high peaks is open only in the summer time. From Walsenburg, the north slope is accessible by driving west on U.S. 160 about 11 mi (18 km) to Colorado 111. Continue 5 mi (8 km) west and south on Colorado 111 to the town of La Veta. Take a country road from the southeast edge of town for about 7 mi (11 km) south and southeast past twin reservoirs to Wahatoya Canyon and the Forest Service Wahatoya trail head at an elevation of about 8,400 ft (2,560 m). The main trail leading south goes to the Bulls Eye Mine, elevation 11,200 ft (3,414 m), on the north slope of West Spanish Peak, elevation 13,626 ft (4,153 m).

Access to the south flank of the Spanish Peaks is from Apishapa Pass, which can be reached by continuing from La Veta south on Colorado 111 about 16 mi (26 km) to Cucharas Pass. Turn left onto the Forest Service road to the northeast and drive about 6 mi (9.6 km) to the trail head at Apishapa Pass (closed in the winter), elevation 11,248 ft (3,428 m). From the pass, a trail leads to timberline on West Spanish Peak at an elevation of about
The mouth of the Grand Canyon and edge of the Colorado Plateau in the Upper Lake Mead area, Arizona
Authors: Lucchitta Ivo
Published: November 2007

The Pierce Ferry area in northern Arizona is easily reached via the paved all-weather Dolan Springs–Meadview road (Fig. 1). The road is poorly maintained, however, and stretches of the pavement have disappeared entirely. The area is also subject to flash floods during the summer thunderstorm season. Meadview, 12 mi (19 km) south of Pierce Ferry, offers modest facilities that include a gas station, country store, motel, and restaurant. A National Park Service ranger stationis nearby.

Even though the upper Lake Mead area as a whole offers interesting geology and breathtaking views, the best place to visit is the northern end of Grapevine Mesa, which affords a truly remarkable overview of much geologic interest and great beauty. This viewpoint, 2.5 mi (4 km) southwest of Pierce Ferry and about 1,700 ft (520 m) higher, is reached by traveling north from Meadview on the paved road to Sand Cove. About 5mi (8 km) north of Meadview, the paved road abruptly drops off the mesa through a narrow slot cut into the resistant limestone that caps the mesa. Just before the slot are a gate and a dirt road to the right (east). This well-graded dirt road is easily passable in dry weather, but not in wet, and leads to the viewpoint at the north end of Grapevine Mesa. Near the viewpoint, on National Park Service land, is a gravel landing strip used routinely by light aircraft of the general public.

The paved road near Meadview affords views of the imposing Grand
Structural geology of the Sawtooth Range at Sun River Canyon, Montana Disturbed Belt, Montana
Authors: Lageson David R.
Published: November 2007

The Sawtooth Range is located in northwest Montana in parts of Pondera, Teton, and Lewis and Clark counties. The range is part of the Rocky Mountain fold and thrust belt, or Disturbed Belt, and lies between Glacier National Park to the north and the Helena salient to the south. In an analogy with the Canadian Rocky Mountains, the Sawtooth Range would represent the Front Ranges of the Rocky Mountain thrust belt (Mudge, 1972; Bally and others, 1966).

The Sun River and its tributaries form the major drainage system in the southern part of the Sawtooth Range. Two dams have been constructed on the Sun River creating Gibson Reservoir and Diversion Lake (Fig. 1).

The entrance to the Sun River Canyon is approximately 20 mi (32 km) northwest of Augusta, Montana. Turn west on Montana 435 (U.S. Forest Service Road 208) at the intersection of highways U.S. 287 and Montana 434–435 in Augusta. Montana 435 is a year-round gravel road that ends at Gibson Dam (Fig. 1). Spectacular exposures of imbricate thrust faults and related structures are found in the lower part of the canyon downstream from Gibson Dam.
Geology along the South Kaibab Trail, eastern Grand Canyon, Arizona
Authors: Beus Stanley S.
Published: November 2007

The South Kaibab Trail head is at the South Rim of the Grand Canyon about 2.25 mi (3.5 km) due east of the National Park headquarters and visitors center at Grand Canyon Village.Convenient access is provided by the paved south entrance road, east Rim Drive Road and Yaki Point Road leading east and north from the village, a driving distance of 3.5 mi (5.75 km) from the Park Headquarters (Fig. 1). Grand Canyon Village at the South Rim is accessible from the south by US 180 and Arizona 64 from Flagstaff (80 mi; 129 km) or by Arizona 64 from just east of Williams (60 mi; 95 km), or from the east via Arizona 64 (57 mi; 92 km) leading west from Cameron.

Detailed geology is shown on the geologic map of the Eastern Grand Canyon, 1:62,500 (Huntoon and others, 1986). A larger scale (1:24,000) topographic, shaded relief map is alavailable (Washburn, 1978), a part of which is used as (Fig. 1).

Overnight motel accommodations and campsites are available at the Grand Canyon Village but generally must be reserved in advance during the major tourist season, April through October. A full day is recommended for a one way traverse of the South Kaibab Trail. Overnight accommodations at the bottom are available at Phantom Ranch or at Bright Angel Creek campground (Park Service permit required), but also generally require reservations several months in advance. The return trip to the rimcan be made back up to the South Kaibab Trail
Geology of the Gray Mountain area, Arizona
Authors: Barnes Charles W.
Published: November 2007

Gray Mountain is a topographic prominence that occupiesmost of the Coconino Point 15-minute Quadrangle, Coconino County, in northern Arizona (Fig. 1). That quadrangle is delimitedby 111°30’ to 111°45’ west longitude, and 35°45’ to 36°00’ north latitude. The total structure extends westerly into the adjacent Grandview Point 15-minute Quadrangle (which includes a very small part of the eastern Grand Canyon), and extends south into the adjacent SP Crater 15-minute Quadrangle.
SP Mountain cinder cone and lava flow, northern Arizona
Authors: Ulrich G. E.
Published: November 2007

SP Mountain is a prominent cinder cone in the northern partof the San Francisco volcanic field near the southern margin of the Colorado Plateau. It is easily visible from U.S. 89 among a cluster of older cinder cones. The area is most readily reached by driving north from Flagstaff about 34 mi (55 km) or south from Cameron 16 mi (26 km) to a graded ranch road that leads westward 5.2 mi (8.4 km). The turnoff is 2.1 mi (3.4 km) north of the entrance to Wupatki National Monument and is marked only by a stop sign. The site is accessible to all vehicles, Ownership of most of the land is divided between the CO Bar Livestock Company and the state of Arizona in a checkerboard pattern of one-mile sections; permission to visit and collect samplesis not required (1984). The northern tip of the SP lava flowextends into the Navajo Indian Reservation (Fig. 1).
Holocene scoria cone and lava flows at Sunset Crater, northern Arizona
Authors: Helm Richard F. , Moore Richard B.
Published: November 2007

Sunset Crater, about 15 mi (25 km) north of Flagstaff, Arizona (Fig. 1), is in the eastern part of the San Francisco volcanic field, on the southern margin of the Colorado Plateau. Access to the Sunset Crater National Monument is by Forest Road 545, an all-weather road off of U.S. 89. Included within the boundaries of the monument are the scoria cone of Sunset Crater and most of one of its associated lava flows, the Bonito flow. Another lava flow associated with Sunset Crater, the Kana-a flow, occurs in the Coconino National Forest east of the monument. Hiking is prohibited on Sunset Crater scoria cone, and collection of specimens is not permitted within the boundaries of the national monument.

Topographic maps published by the U.S. Geological Survey that cover the monument and surrounding area are the Sunset Crater East, Sunset Crater West, O’Leary Peak, and Strawberry Crater quadrangles of the 7%-minute series. The geology of the area is shown by Moore and Wolfe (1976).
Meteor Crater, Arizona
Authors: Shoemaker Eugene M.
Published: November 2007

The location of Meteor Crater is shown on nearly all high-way maps of Arizona. It lies 6 mi (9.7 km) south of 1-40 between Flagstaff and Winslow in northern Arizona; the turnoff from 1-40, 34 mi (55 km) east of Flagstaff, is well marked by signs along the highway.Access to the crater is by a paved road that leads directly to a visitor center and museum on the rim of the crater. Qualified scientists may obtain permissio to hike to various parts of the crater by writing or calling in advance to Meteor Crater Enterprises, 121 East Birch Avenue, Flagstaff, Arizona 86001.
Petrified Forest National Park, Arizona
Authors: Ash S. R.
Published: November 2007

Petrified Forest National Park is located near the southern margin of the Colorado Plateau in the Painted Desert area of east-central Arizona (Fig. 1). The park extends about 26 mi (42 km) north and south. The north entrance is about 68 mi (109 km) west of Gallup, New Mexico, on 1-40 and the south entrance is on U.S. 180 about 17 mi (27 km) east of Holbrook, Arizona. Visitors traveling west can leave 1-40 at exit 311 and enter the park at the north entrance. After entering the park they may follow the scenic park road southward to the southern exit, a distance of about 27 mi (43 km). They then can travel westward on U.S. 180 to Holbrook where they rejoin 1-40. Visitors traveling east may leave 1-40 at exit 285 at Holbrook and drive east on U.S. 180 to the south entrance of the park, a distance of about 18 mi (29 km). Frequent pullouts and short side roads are present throughout the park. Much of the park is accessible to all types of vehicles, although their use is restricted to established roads. There are also two large, undeveloped, wilderness areas in the park. The removal of petrified wood or any other natural, archeological, or historical object from the park is strictly prohibited.
Shonkin Sag laccolith; A differentiated alkaline intrusion, Highwood Mountains, Montana
Authors: Nash W. P. , Monson Lawrence M.
Published: November 2007

The Shonkin Sag laccolith is on the northeast flank of the Highwood Mountains in Sec. 22–27, T.2 1N., R.11 E., in Choteau County, Montana. The laccolith lies entirely within the Geraldine, Montana, 1:24,000 Quadrangle. It is approximately 44 mi (71 km) east of Great Falls and 54 mi (87 km) northwest of Lewiston. The nearest town is Geraldine, about 3 mi (5 km) to the north (Fig. 1). The best access is through Geraldine, which lies on Montana 80,27 mi (43 km) south of Fort Benton or 38 mi (61 km) north of Stanford. The shortest route from Great Falls is by way of U.S. 87 to Geyser, a distance of 47 mi (76 km). From Geyser, a gravel road can be used to reach the Buck Ranch access, 27.3 mi (43.9 km) to the north. This route contains many excellent outcrops and views of other alkalic igneous bodies, including Square Butte and Round Butte. Outcrops of the Shonkin Sag laccolith can be seen on the Buck Ranch, which is entered 3.7 mi (6.0 km) south of Geraldine (Fig. 2). Follow the ranch access 1.5 mi (2.4 km) to the ranch buildings. The western outcrop is adjacent to this road. Trails east of the ranch yard lead to the top of the laccolith and permit easy examination of an entire cross section by traversing down the canyon draining to the southwest. This cross section can be viewed from the Flat Creek Road, which intersects Montana 80, 0.5 mi(0.8 km) north of the small town of Square Butte
The Vanes Caldera, Jemez Mountains, New Mexico
Authors: Nault Kenneth J. De
Published: November 2007

The Vanes Caldera is in Sandoval County, New Mexico (Fig. 1). The caldera, subsequent resurgent dome, later intracaldera domes and flows, and present solfatara activity can be seen from New Mexico 4. Most of the caldera floor itself is owned or controlled by the Baca Ranch and is not accessible. In winter, New Mexico 4 is intermittently closed through the caldera due to ice or snow.
The Emory resurgent ash-flow tuff (ignimbrite) cauldron of Oligocene age, Black Range, southwestern New Mexico
Authors: Elston Wolfgang E. , Seager William R. , Abitz Richard J.
Published: November 2007

The Emory cauldron is traversed by New Mexico 90 about 35 mi (55 km) east of Silver City, in southwestern New Mexico.
Paleozoic reef complexes of the Sacramento Mountains, New Mexico
Authors: Bowsher Arthur L.
Published: November 2007

Reef complexes of Mississippian, Pennsylvanian, and Early Permian age are conspicuous in the western escarpment of the Sacramento Mountains of southeastern New Mexico (Fig. 1). The coincidence of reef trends and the fault zone at the western front of the Sacramento Mountains appears to be significant. The basement fault zone on the western edge of the Sacramento block created platform margins along which Paleozoic shelf-edge reefs accumulated. Facies in Late Paleozoic formations were strongly controlled by structural trends in the Precambrian basement rocks. The Sacramento escarpment lies parallel to and adjacent to the western margin of the "Pedernal Landmass” (Pray, 1961) that trends northerly, as do the Sacramento Mountains.

The La Luz Anticline (Pray, 1961) in the northern part of the Sacramento Mountains plunges to the north(Fig. 1). Beds on the west limb dip 8 to 12 degrees. Numerous deep canyons off this west flank expose thick sequences including nearly all the Paleozoic formations. Exposures perpendicular to the reef-trends thatare available in these canyons (Fig. 2) are unique. Facies Figure changes in the reef complexes are readily available to the field geologist. This area of the Sacramento Mountains is of extreme importance to students of carbonate rocks because of the excellent, numerous, and distinct exposures of the reef complexes.
Upper Cretaceous-Paleocene sequence, Bug Creek area, northeastern Montana
Authors: Sloan Robert E.
Published: November 2007

The area described here is in McCone County, Montana, approximately 100 mi (160 km) northwest of Glendive and 40 mi (64 km) south of Glasgow, on the east side of the Big Dry Arm of the Fort Peck Reservoir. It is located on the Jordan 1:250,000-scale map, the Fort Peek Lake East 1:100,000-scale map, and the Bug Creek 1:24,000-scale topographic map. The Bug Creek area (Fig. 1) is reached by proceeding south on Montana 24 for 24 mi (39 km) from the Fort Peck Dam or north 25 mi (40 km) from the intersection of Montana 200 with Montana 24. At this point a dirt road heads due west for 2.5 mi (4 km), then swings north at the rim of a mesa, and then swings south to the crossing of Bug Creek. The dirt road is passable by any vehicle when dry; four-wheel drive is required when the road is wet. The dirt access road is about 2.5 mi (4 km) south of the crossing of Montana 24 over the South Fork of Rock Creek and 5.5 mi (8 km) south of the road sign to Rock Creek State Park. More than 2 mi (3 km) west of Montana 24, the land is part of the Charles M. Russell National Wildlife Range. Much of the other land is controlled by the U.S. Bureau of Land Management (BLM); some is privately owned. Collection of vertebrate fossils on federal land is by permit only. No permission is required to examine exposures on federal or state land;
Banded Castile evaporates, Delaware basin, New Mexico
Authors: Anderson Roger Y. , Kirkland Douglas W.
Published: November 2007

This site is located along U.S. 62, 0.75 mi (1.2 km) north of the Texas-New Mexico state line and 12 mi (20 km) southwest of Carlsbad Caverns (Fig. 1). This is the main two-lane highway between Carlsbad, New Mexico, and El Paso, Texas. The shoulder of the highway at the outcrop is wide enough to accommodate a single row of cars. The geographic relationship of the outcrop to the Gypsum Plain, a vast expanse (1000 sq mi—2600 sq km)of outcropping gypsum, and to other physiographic features in the vicinity is shown in Figure 1.
Marysville stock and contact aureole, western Montana
Authors: Derkey Robert E. , Derkey Pamela Dunlap
Published: November 2007

The Marysville stock is about 17 mi (27 km) northwest of Helena, Montana, in Lewis and Clark County (Fig. 1). To reach the area from Helena, go7mi(11 km) north on 1–15 to exit 200 and turn west (left) off the exit ramp onto Montana 279 (Lincoln Road). At 8.5mi(14km) from 1-15, turn southwest (left) onto a gravel road marked by signs for Marysville and the Belmont Ski Area. The old mining town of Marysville is about 6 mi (10 km) from this turnoff. Most of the area is readily accessible by passenger car although some areas are accessible only by four-wheel drive or foot (Fig. 2). The mines are on private land. Permission should be obtained from owners with posted land or locked gates.
The McConnell thrust at Mount Yamnuska, Alberta, Canada
Authors: Gretener P. E.
Published: November 2007

McConnell thrust can be reached by driving west from Calgary for 49 mi (78 km, official mileage from the city’s center) along the Trans-Canada (T-C) Highway 1 to the intersection with T-C 1X leading north to the old Calgary-Banff highway (T-C 1A; Fig. 1). Those in a hurry to get to Banff may go past the intersection to viewpoint no. 3 for a distant view of the McConnell thrust, which rises from the valley floor up a ramp into the saddle on the west side of Mt. Yamnuska (Fig. 2). A small splay fault occurs in the saddle, and the eastward continuation of the thrust along the base of the Yamnuska wall is essentially horizontal in the direction of transport. For a closer view, turn north onto T-C 1X and stop at the entrance to the campground; better yet, proceed to the vicinity of the junction with T-C 1A and pull over onto the shoulder for a view as in Figure 3. In all cases, field glasses will be helpful. Those ardent souls who wish to touch the thrust plane should turn east on T-C 1A and drive for 1.3 mi (2.1 km) to the dirt road leading northwest into the quarry at the foot of Mt. Yamnuska. They may park here and then proceed on foot to the upper east end of the marked shale coulee (Fig. 4)—a steep climb of about 1,600 ft (480 m), which should take about 1% hours.
Mississippian Waulsortian bioherms in the Big Snowy Mountains, Montana
Authors: Smith Donald L. , Custer Stephan G.
Published: November 2007

Mississippian-age Waulsortian bioherms in the Lodgepole Formation are well exposed and accessible for field study in Swimming Woman Canyon, Big Snowy Mountains, Central Montana. Swimming Woman Canyon is east of Judith Gap, northeast of Harlowtown, and north of Rygate, Montana (Fig, 1). The site can be reached by automobile via gravel roads from U.S. 191 or from U.S. 12. Three routes to the site are shown. The route selected will depend on the direction the visitor is traveling. Travelers using the Judith Gap route may be tempted to continue east after driving 15 mi (24 km). Part of the road to the east of this point has been abandoned.

Mileages to turns along the route can be scaled from Figure 1, which is adapted from the Roundup I × 2° Army Map Service (AMS) sheet published by the U.S. Geological Survey. The only other available access map is the Lewis and Clark National Forest (Jefferson Division), Montana, Forest Visitor’s Map (planimetric) at a scale of 1:126,720. No topographic map at a scale larger than 1:250,000 is currently available. The Irene 3 NE 1:24,000 Topographic Quadrangle covers the field area and is in preparation. Travelers may want to keep track of mileage using their automobile odometer while off the main highway. The distances from the various starting points to Swimming Woman Canyon Road are: 25 mi (40.2 km) from Judith Gap, 24.2 mi (38.9 km) from Rygate.
The Stillwater Complex, southern Montana; A layered mafic intrusion
Authors: Atkinson W. W. , Derkey Robert E.
Published: November 2007

The Stillwater Complex is about 75 mi (120 km) southwest of Billings, Montana, and northeast of Yellowstone National Park (Fig. 1). Exposures of the NE-dipping complex extend over a 30-mi-long (48 km) strike along the north margin of the Beartooth Mountains. The Benbow and Mountain View areas southwest of Absarokee, Montana (Fig. 1), are readily accessible by passenger car. The Benbow area offers easy access to a variety of rocks from the ultramafic series and chromite deposits but only limited exposures of features from the banded series. The Mountain View area offers easy access to most of the banded series and the platinum deposits.

The Benbow and Mountain View areas are reached by exiting 1-90 at Columbus, Montana (Fig. 1), onto Montana 78 and proceeding south to Absarokee. County Highway 419 to both areas begins 2.5 mi (4.0 km) south of Absarokee. It is a narrow blacktop road that passes through Fishtail, where a small motel and restaurant are located. The Benbow turnoff at Dean, a collection of several houses, is 13.9 mi (22.4 km) from Montana 78. Turn left onto the gravel road marked “Benbow mine” if you wish to tour the Benbow area (Table 1). Continue on County Highway 419 if you wish to tour the Mountain View area (Table 2). The Nye Post Office and Carters Camp are located 20.4 mi (32.8 km) from the Montana 78 junction. Continuing ahead 5.4 mi (8.7 km) will bring you to the platinum mining operations at the end of the backtop road.
A study in contrasts
Authors: Mueller Paul A. , Locke William W. , Wooden Joseph L.
Published: November 2007

The Beartooth Highway (U.S. 212) lies southwest of Billings, Montana (Fig. 1). The section of highway discussed here extends from Red Lodge, Montana, to Cooke City, Montana. The road is paved and well maintained, but it may be temporarily closed by snow as early as Labor Day. It closes for the season by middle to late September, and remains closed until mid-May. The stops discussed here (Fig. 1) are pullouts (4 to 6 cars) on the highway and are accessible by two-wheel drive cars. Other than pullouts the road is narrow, with little possibility of overflow parking. Land ownership is largely National Forest (Gallatin and Custer in Montana, Shoshone in Wyoming) with the exception of private holdings along Rock Creek below the switchbacks.