bluuebunny/crossref_metadata_2025 huggingface dataset:
Cambrian and Ordovician stratigraphy in the Lansing area, northeastern Iowa
Authors: Witzke Brian J. , Mckay Robert M.
Published: November 2007

The oldest Paleozoic rocks exposed in Iowa are found in the northeastern corner of the state in Allamakee County. Cambrian exposures in the county form part of the classic reference area in the Upper Mississippi Valley for the Upper Cambrian Croixan Series. Overlying dolomites of the Prairie du Chien Group are exposed as bold cliffs in the bluffs along the Mississippi River and its tributaries. Cambrian and Lower Ordovician strata collectively encompass the Sauk Sequence, the first large-scale transgressive-regressive cratonic marine cycle of the Phanerozoic (Sloss, 1963). A major episode of erosion followed deposition of the Sauk Sequence. A widespread unconformity separates Lower and Middle Ordovician strata in the region, marking the boundary between the Sauk Sequence and the succeeding Tippecanoe Sequence.

The most complete sequence of Cambrian and Ordovician strata in northeast Iowa is exposed between Lansing and Church as one ascends from the Mississippi River up the valley of Clear Creek to the crest of Lansing Ridge along Iowa 9 (Fig. 1) 1). Vertical relief along this profile is 630 ft (192 m), and the composite stratigraphic section measured totals 619 ft (189 m). The base of the section begins along Iowa 26 north of the Mississippi River bridge (loc. 1, Fig. 1), and continues through a series of roadcuts and natural exposures in Mount Hosmer Park (loc. 4, Fig. 1). Strata equivalent to the lower half of the section at locality 1 can be seen behind Knopf’s Standard Station
The Lime Creek Formation of north-central Iowa
Authors: Anderson Wayne I. , Furnish William M.
Published: November 2007

There are three principal exposures of the Lime Creek Formation in the area between Mason City and Charles City, northern Iowa. By a considerable margin, the most extensive site is the quarry of the former Rockford Brick and Tile Company, only 1 mi (1.6 km) west of town in Floyd County (NW¼Sec. 16, T.95N., R.18W.). The Juniper Hill State Preserve is 0.5 mi(0.8 km) to the northwest. Bird Hill is located just a fe miles farther west at a road cut on an east-west county right-of-way in eastern Cerro Gordo County (NE½Sec.24, T.95N., R.19W.). The stratigraphic section known historically as Hackberry Grove, now called Claybanks Forest, lies just south of the Winnebago River (near center NE½Sec.34, T.96N., R.19W.). The Winnebago River was originally called Lime Creek (hence the name Lime Creek Formation). A location map (Fig. 1) has been prepared from the general highway and transportation maps of Cerro Gordo and Floyd counties. Topographic sheets for the Mason City Southeast and Rockford 7½-minute Quadrangles cover the area.

The Rockford Brick and Tile property lies adjacent to County Road B47, west of Rockford. The kilns have been inactive for several years, and permission to visit the grounds must be secured from the present owner, Allied Construction Company, 1211 South Main Street, Charles City, Iowa 50616. Bird Hill is also situated on County Road B47, with a large parking area on the north side of the road. The site has recently been designateda State Preserve. At Hackberry Grove, the Claybanks
Cretaceus exposures, Big Sioux River Valley north of Sioux City, Iowa
Authors: Witzke Brian J. , Ludvigson Greg A.
Published: November 2007

Cretaceus exposures in the Sioux City area, primarily along the Big Sioux River in Iowa and the Missouri River Valley in northeast Nebraska, were of considerable importance in the early formulation of stratigraphic nomenclature in the Western Interior Province (Tester, 1931). It was from this area that Meek and Hayden (1862) originally named the “Dakota Group,” the basal subdivision of Cretaceus rocks as used throughout much of the western U.S. A summary of Cretaceus stratigraphy and paleogeography in the Iowa area is given by Witzke and others (1983).

The east side of the Big Sioux River Valley reveals a series of Cretaceus exposures (Fig. 1) that are among the best in Iowa. Many of the exposures are along the Iowa 12 right-of-way and are publicly accessible (localities 1, 2, 3, 4, 8). Roadside exposures in Stone State Park (localities 5, 6) and old shale pit operations at Kirk Hanson Recreation Complex in Riverside (locality 9) are also publicly accessible, but collecting is discouraged. Other exposures are on private land, and permission must be secured before entering (e.g., shale pit of Siouxland Sand and Gravel, locality 7). Many of the exposures are extremely steep and potentially hazardous; please exercise caution.

A general description of Cretaceus rock units examined and measured at localities 1 through 9 (Fig. 2) is given in the Measured Section. Strata at locality 10 (Fig. 2) are poorly exposed and the illustrated section is adapted from
Exposures of the Fort Hays Limestone Member, Niobrara Chalk (Upper Cretaceus) near Stockton, Kansas
Authors: Laferriere Alan P.
Published: November 2007

A complete section of the Fort Hays Limestone Member occurs within roadcuts along Kansas 24, 2.4 mi (3.8 km) west of Stockton (Stockton 7½-minute Quadrangle) in NE¼Sec.21, T.7S., R.18W., Rooks County, Kansas (Fig. 1). At this locality, a series of three roadcuts occurs within a 0.25-mi (0.4 km) stretch of highway. Stratigraphically higher beds of the Fort Hays crop out at the east end of the exposures. By utilizing all three outcrops, most beds of the unit can be examined near road level with a minimum of climbing.
Hydrocarbon-induced diagenetic aureole at Cement-Chickasha Anticline, Oklahoma
Authors: Al-Shaieb Zuhair
Published: November 2007

The Cement-Chickasha Anticline includes parts of Caddo and Grady counties in southwestern Oklahoma (Fig. 1). The structure is elongated and trends in a northwesterly direction. The town of Cement is located in the central part of the structure. Three major highways intersect the site. The H. E. Bailey Turnpike extends diagonally across the southeastern portion of the site, while U.S. 277/Oklahoma 19 trends east–west through the southern half of the site and connects the towns of Cement and Cyril. Oklahoma 8 trends north-south through the western portion of the site and terminates at the town of Cyril.
Spillway fault system, Tuttle Creek reservoir, Pottawatomie County, northeastern Kansas
Authors: Underwood James R. , Poison Allyn
Published: November 2007

The best exposure of the Spillway fault system is in the northwest wall of the northwest-trending spillway of Tuttle Creek reservoir (SW¼, SE¼SW¼, Sec.18, T.9S., R.8E.) in westernmost Pottawatomie County, immediately northwest of the point where Kansas 13 crosses the spillway (Fig. 1). From Manhattan, Kansas, drive north-northwest on Tuttle Creek Boulevard (also US 24, Kansas 13 and 177) 3.6 mi (5.7 km) from its intersection with Kimball Avenue to the point where Kansas 13 turns right (northeast). Drive 1.8 mi (2.9 km) across the dam to the parking areas on both sides of the road that overlook the spillway to the northeast.
Carboniferous flysch, Ouachita Mountains, southeastern Oklahoma; Big Cedar-Kiamichi Mountain section
Authors: Moiola R. J. , Briggs G. , Shanmugam G.
Published: November 2007

Located in LeFlore County (Big Cedar and Octavia 7½-minute Quadrangles), the Big Cedar–Kiamichi Mountain section is continuously exposed in roadcuts that parallel U.S. 259 (Figs. 1, 2, 3). Commencing 2.6 mi (4.2 km) south of the Big Cedar intersection of Oklahoma 63 and U.S. 259, at the contact between the Stanley and Jackfork Groups (Fig. 3), an uninterrupted sequence of Jackfork is superbly exposed as the road climbs up to and beyond the summit of Kiamichi Mountain. Reinterpretation (Briggs, 1973, and this text) of the section Cline and Moretti (1956) measured at the time U.S. 259 was under construction indicates that 6,604 ft (2,013 m) of Jackfork are present (Fig. 2). The roadcuts are accessible all year, but caution must be exercised by parking cars well off the road, being careful of traffic, and avoiding dangerous areas with high rock faces or areas that may have loose or falling rocks.
Turner Falls Park; Pleistocene tufa and travertine and Ordovician platform carbonates, Arbuckle Mountains, southern Oklahoma
Authors: Donovan R.N. , Ragland D. A. , Schaefer D.
Published: November 2007

Turner Falls Park is located in the Arbuckle Mountains approximately 3 mi (4.8 km) south of Davis on U.S. 77. The park is shown on all highway maps of Oklahoma, and the easiest access is from appropriate exits on I-35 (Fig. 1). There is a small charge for entering the park.

The best-known view of Turner Falls is from the overview gift shop on U.S. 77 (free parking available). From here all the sites described below can easily be visited, although the descent to the falls is via rather steep steps. The less agile who wish to view the falls closely can enter the park via the automobile entrance (which is located approximately 0.5 mi [0.8 km] north of the gift shop). From here it is an easy walk to the foot of the falls. Alternatively it is possible to park above the falls; this is an easy way to examine the top of the old travertine deposit.

No hammers please; the exposures (which are highly photogenic) could easily be ruined.
Pennsylvanian conglomerates in the Arbuckle Mountains, southern Oklahoma
Authors: Donovan R.N. , Heinlen W. D.
Published: November 2007

Two formations illustrate the characteristics of Pennsylva-nian conglomerates in the Arbuckle Mountains of southern Oklahoma the Vanoss Formation and the Conings Ranch Conglomerate.

The Vanoss Formation is exposed on Bromide Hill in Platt National Park which is located on the southern edge of Sulphur and is easily reached by good roads from all directions (Fig. 1). To gain access to the area, follow U.S. 177 south from Sulphur into the park. Approximately 900 ft (300 m) inside the park boundary, immediately after crossing Rock Creek, turn west and follow the perimeter drive for about 1 mi (1.4 km) to Bromide Pavilion (Fig. 2).

The Conings Ranch Conglomerate is exposed on both sides of I-35 and in the median, approximately halfway between the Davis and Turner Falls turnoffs, and forms part of the magnificent Arbuckle Mountains road cuts (Fig. 1) (see also Fay, this volume). A rest area, which provides a lay person’s explanation of the geology, is conveniently located at the southern margin of the Conglomerate on the south lane of I-35. The principal outcrops are between Interstate Stations 2600 and 2630 as designated by the Oklahoma Department of Highways.
Minor T-R units in the Lower Permian Chase Group, northeast Kansas
Authors: Busch Richard M.
Published: November 2007

Site 4: Roadcuts between mile markers 4.4 and 4.6 along east and west sides of Kansas 113 (Seth Childs Road), from 1.25 to 1.45 mi (2 to 2.3 km) south of its intersection with Kansas 24, at the northwest edge of Manhattan, Riley County, Kansas, NW¼, Sec.35, T.9S., R.7E.

Site 5: Roadcuts along the north side of 1-70, between mile markers 306.6 and 307, starting 0.85 mi (1.4 km) west of the overpass for Exit 307 to McDowell Creek Road, Geary County, Kansas, NW¼, Sec.28, T.llS., R.7E.
Structural styles in the Arbuckle Mountains, southern Oklahoma
Authors: Tapp J. Bryan
Published: November 2007

This chapter describes structural features of outcrops in the Arbuckle Mountains, southern Oklahoma, along I-35 and near Arbuckle Lake. The stops are arranged as though the reader is driving south from Oklahoma City toward Dallas. For a description of stratigraphic stops along this same route, and for a generalized location map and cross sections, the reader is referred to the preceding chapter by Fay. The body of the discussion of outcrops evaluates evidence that the structures and sediments seen in the Arbuckle Mountains formed in an aulacogen that has undergone left-lateral-wrench deformation. All of the outcrops along I-35 are public domain. Parking along the interstate is tolerated as long as vehicles are pulled well off of the roadway and groups or individuals do not cross the highway. If a large group is to examine the exposures, it would be best to park in the scenic turnouts and walk along the highway shoulders. The outcrop described near Arbuckle Lake is in a county-owned quarry that is usually inactive on weekends.
Beavers Bend State Park, Broken Bow Uplift, Oklahoma
Authors: Nielsen K. C.
Published: November 2007

Beavers Bend State Park is located approximately 10 mi (16 km) north of Broken Bow, on U.S. 259A. In this park the Mountain Fork River has cut an entrenched meander loop into the Middle Paleozoic flank sequence of the Broken Bow Uplift (Fig. 1). As such, this is a convenient locality to examine the stratigraphic sequence and the structural style of the central uplift of the Ouachita Mountains of Oklahoma.

Within the park, U.S. 259A forms a loop east of U.S. 259 (Fig. 1). There are several good hiking trails; therefore, many of these stops will involve light hiking in order to examine the sequence. Also, detailed maps are provided in Figures 1 and 3 in the hope that interested people will hike independently to study the anatomy of these structures.

The stratigraphic sequence (Site 45) is examined in two stages. The Womble Shale through the Blaylock Sandstone are discussed at the Stephens Gap Area (Locality 5). The Blaylock Sandstone up to the Lower Stanley Shale is reviewed near the Power Station (Locality 2).
The Paleozoic rocks of the Ponca region, Buffalo National River, Arkansas
Authors: McFarland John David
Published: November 2007

Three state highways provide the primary access to the Ponca region (Fig. 1). They are Arkansas 21, 43 (both northsouth), and 74 (east-west). Three campgrounds are located in the area: Lost Valley, Steel Creek, and Kyle’s Landing. These are all Buffalo National River campgrounds and designed for the tent camper.

The roads leading into each camp are gravel and, in the case of Steel Creek and Kyle’s Landing, involve steep grades. Each camp has excellent outcrops within easy walking distance. The roadcuts and mines are easily accessible by passenger car and short walks. Although some of the river exposures may be reached by road or on foot, the ideal mode of travel is by canoe. Unfortunately, water levels typically allow canoe travel for only a few months in the winter and spring. The river in this area is rated class I-II white water, with fairly frequent, generally unobstructed rapids. During the floating season, canoes may be rented from any of several outfitters in Ponca.

The exposures along the River and around the campgrounds are within the boundaries of the Buffalo National River and are under the protection of the National Park Service. Please respect this reservation. Roadcuts in the immediate area but outside the park provide ample outcrops for sample collection.
Silurian rocks of northern Arkansas
Authors: Wise O. A. , Caplan W. M.
Published: November 2007

From Batesville, Arkansas, in Independence County, follow Arkansas 69 north to Cushman (Fig. 1). Turn left (west) on the county road (paved) just beyond the Cushman General Store. If you consider this intersection the zero point of a road log, the pavement ends at about mile 3.5 (5.6 km). At mi 5.1 (8.2 km) you will drive past a good outcrop of Ordovician age limestones of the Plattin, Kimmswick, and Fernvale formations. Of particular interest here is the Plattin-Kimmswick contact, which is sharp and “welded” as well as angular. The Plattin occurs in a small synclinal fold that is truncated by the basal sandy Kimmswick. An orange-colored zone several yards up the road marks a fault that lowers the Fernvale to a position adjacent to the Kimmswick at road level. (See W. W. Craig’s discussion of the lithologies of these units elsewhere in this volume.) At mi 7.0 (11.3 km) is the entrance to Love Hollow Quarry (Fig. 2). The outcrop described below can be found approximately 0.2 mi (0.3 km) north of Love Hollow.

The exposure consists of approximately 60 ft (18 m) of Brassfield, St. Clair, and Lafferty limestones. The shale on which the Brassfield rests at this locality is probably Ordovician age. The lithologic sequence consists of 4 ft (1.2 m) of spar-cemented, coarse fossil debris, overlain by 4 ft ( 1.2 m) of St. Clair, which in this locality is represented by a biomicrite. The contact at this point is slightly angular. The St. Clair is
Horsehead Lake spillway, Arkansas
Authors: McFarland J. D.
Published: November 2007

Horsehead Lake is a small U.S. Forest Service lake located in western Johnson County, Arkansas, at the juncture of the Boston Mountains and the Arkansas River Valley (Fig. 1). To reach the lake, take Arkansas 164 north from 1-40 (the Hunt-Coal Hill exit). From downtown Hunt, continue 2.8 mi (4.5 km) north on Arkansas 164 to the entrance to Horsehead Lake. Walk across the dam to the spillway cut.
Barneston Limestone (Lower Permian) of eastern Kansas
Authors: Twiss Page C. , Underwood James R.
Published: November 2007

The Barneston Limestone is well exposed on the north side of the road cut at milepost 305 on 1-70 in NW¼SW¼Sec.30, T.1lS., R.6E., Geary County, Kansas (Fig. 1), about 10 mi (16 km) east of Junction City. Vehicles traveling east should continue to exit 307 (McDowell Creek Road), pass under 1-70, and return westward to milepost 305. Because Kansas law prohibits pedestrians from crossing a divided highway, vehicles should be parked on the north side, off the pavement and passengers should exit on the right-hand side. Keep far away from the traffic lanes while examining the rocks. The upper two-thirds of this section can be examined closely by walking up the hill on the west side of the road cut.
Lower Stanley Shale and Arkansas Novaculite, western Mazarn Basin and Caddo Gap, Ouachita Mountains, Arkansas
Authors: Zimmerman Jay , Ford James Timothy
Published: November 2007

Elements of the sedimentology and structural geology of two of the most prominent lithologic units in the Arkansas Ouachitas, the Arkansas Novaculite (Devonian-Mississippian), and the Stanley Shale (Mississippian), are illustrated along a 6.1 mi (9.8 km) highway traverse between the village of Glenwood and Caddo Gap, Arkansas. The outcrops described below serve as an introduction to the two broad facies groups present in the Ouachita Mountains and to the structural style that dominates major parts of the range.
Turbidite exposures near DeGray Lake, southwestern Arkansas
Authors: McFarland J. D.
Published: November 2007

DeGray Lake maybe reached by taking Exit 78 from 1-30 just north of Arkadelphia, Arkansas, and proceeding north on Arkansas 7. The access road to the dam area is approximately 3 mi (4.8 km) from the exit.
The upper Jackfork Section, Mile Post 81, I–30, Arkadelphia, Arkansas
Authors: Stone Denise M. , Lumsden David N. , Stone Charles G.
Published: November 2007

A readily accessible 440-ft (132 m) section of the upper Jackfork Sandstone crops out along 1-30 near Arkadelphia, Arkansas. The outcrop is on the west side of 1-30 between Exits 83 (Friendship) and 78 (Arkadelphia, Hot Springs) at the Mile Post 81 marker (Fig. 1).
The DeQueen Formation at the old Highland Quarry, Arkansas
Authors: McFarland J. D.
Published: November 2007

To reach the Highland Quarry, start at the junction of Arkansas 24 and 27 at the north edge of Nashville, Arkansas. Drive north on Arkansas 27 (toward Murfreesboro) for 8.6 mi (13.9 km) and turn left (west) on Arkansas 26 (Fig. 1). The gravels at this junction are units of the Tokio Formation (Upper Cretace- US). Drive 1.6 mi (2.6 km) to the west on Arkansas 26 to the entrance of the quarry. Enter the quarry and ask permission at the mine office. The most convenient exposures are on the west wall of the quarry (Figs. 2, 3). This end of the quarry has been inactive for several years, but if you follow the road through the quarry for 2 mi (3.2 km) or so you will reach more recently developed pits.
The Claiborne Group in southwest Arkansas
Authors: Prior William Lee , Baber Quin
Published: November 2007

Although the middle Eocene age Claiborne Group of southwest Arkansas covers a large area, outcrops are sparse. The easily erodable Claiborne is composed of unconsolidated sand, silt, clay, and lignite. It has a maximum thickness of 1,500 ft (457 m) in Arkansas, generally strikes to the northeast, and dips an average 60 ft to the mi (11 m to the km) to the southeast. The exposures at Camden and Red River in southwestern Arkansas (Fig. 1) display features of a deltaic plain environment. The two exposures are 75 mi ( 120 km) apart and are probably of different parts of the Claiborne section. Currently, the Claiborne Group is interpreted as having accumulated in fluvial-deltaic system. Studies by Bernard and others (1970) have established a classification scheme of sedimentary environments within deltas. Texture, fabric, sedimentary features, geometry, and trends of sediments associated with deltas are controlled by geologic processes and the availability and influx of different sediment types. Based on these criteria, delta depositional environments have been divided into (1) delta plain with natural levees, distributary channels, interdistributary marshs, and flood basins; (2) inner fringe with rivermouth bars; (3) outer fringe; (4) prodelta; and (5) open marine (Figs. 2 and 3). These environments are discussed within the context of high sediment influx, low energy type of coastal delta (birdfoot, lobate) interpretation of the Claiborne Depositional system, as opposed to low sediment, high coastal energy deltas (arcuate, estuarine).
Permian strata of North-Central Texas
Authors: Jones James O. , Hentz Tucker F.
Published: November 2007

Permian sedimentary rocks of North-Central Texas are exposed in a northeast-striking outcrop belt that extends from overlying Cretaceus strata composing the Edwards Plateau in the south to the Red River and Panhandle region in the north. The gently inclined (0.50), west-dipping Permian strata, over 5,500 ft (1,680 m) of section, are represented in this chapter as a transect of about 180 mi (290 km) in the northern part of the outcrop area (Fig. 1).
The Claiborne Group of East Texas
Authors: Sharp Patricia S. , Sartin Austin A.
Published: November 2007

An ancestral coastal plain was the principal setting for the deposition of the Claiborne Group. Units within the Claiborne dip to the southeast at one to two degrees. Generally the Claiborne formations crop out in an arcuate pattern across the east Texas area, with the older formations cropping out farther to the north and west while the younger formations crop out nearer to the present coast.

The ancestral coastal plains area of Texas consists of several major structural features: Sabine Uplift in extreme East Texas, Tyler Basin in east Texas, San Marcos Arch in central Texas, and Rio Grande Embayment in southern Texas (Fig. 1). Formation of these structural features influenced the deposition of the Claiborne units. High areas, such as the Sabine Uplift and the San Marcos Arch, caused rivers to reroute and diverge their courses. This resulted in minimal amounts of material being deposited in those areas of uplift. Subsidence created the basinal features such as the Tyler Basin and Rio Grande Embayment, and great thicknesses of material were deposited in these susiding lows. Normal faulting has vertically displaced the Claiborne units throughout the area.

Claiborne exposures discussed here are located within approximately 6 mi (10 km) of Jacksonville, Texas, in Cherokee County (Fig. 2). Outcrops that primarily expose the Queen City and Weches formations are easily accessible along U.S. 69 north and south of Jacksonville and along U.S. 79 west of Jacksonville. In several localities, upper and lower contacts of the Queen City and Weches formations are visible. The formations are
Cambrian algal reefs of the upper Wilberns Formation, central Texas, The Camp San Saba locality
Authors: Ahr Wayne M.
Published: November 2007

The famous algal reefs of the upper Wilberns Formation in central Texas are well illustrated by the section at the Camp San Saba crossing on the San Saba River, McCulloch County, Texas (Figs. 1, 2). These reefs are entirely within the San Saba Member of the Upper Cambrian Wilberns Formation (Barnes and Bell, 1977).
The Precambrian of Central Texas
Authors: Barnes Virgil E.
Published: November 2007

“Precambrian rocks reach the surface in the Llano region of Central Texas in the highest part of a broad domal arch, the Llano uplift, which appears on a regional geologic map as an island of igneous and metamorphic rocks surrounded by Paleozoic and Cretaceus sedimentary rocks. The widest expanse of Precambrian rocks is about 65 mi ( 105 km), extending westward from the valley of the Colorado River through a subdued topographic basin drained by the Llano River. The broad, gentle basin carved into the Precambrian rocks is bordered by a discontinuous rim of flat-topped limestone hills which are the dissected edge of the Edwards Plateau. Within the basin and at its margins are erosional remnants and down-faulted blocks of Paleozoic rocks which form prominent hills, locally referred to as mountains.” Clabaugh and McGehee (1972, p. 9).

The main Precambrian units present in the Llano region are listed in Table 1, and the distribution of some of these units is shown in Figure 1. This figure is derived from the Llano Sheet of the Geologic Atlas of Texas, scale 1:250,000 (Barnes, 1981). On that map (as well as Fig. 1), the Oatman Creek and Sixmile Granites (Table 1) are lumped as younger granitic intrusive rocky locally, in the southeast part of the Llano Sheet, the Packsaddle Schist is subdivided into four formations (McGehee, 1979). Detailed 7½-minute quadrangle maps include most of the area in which the Packsaddle Schist has been subdivided (Barnes and McGehee, 1976; 1977a, b, c).
The Catahoula Formation; A volcaniclastic unit in east Texas
Authors: Ledger Ernest B.
Published: November 2007

The Oligocene/Miocene Catahoula Formation of the upper Texas coastal plain is a fluvial and lacustrine volcaniclastic unit composed of “normal” quartz-rich fluvial material mixed with distal rhyolitic air-fall ash from coeval volcanic source areas in Trans-Pecos Texas and northern Mexico. It consists of poorly sorted siltstones, sandstones, and mudstones. The silt-size fraction includes abundant, slightly altered, volcanic glass shards. Sandsize grains are mostly quartz, some of which are very coarse—the “rice sands”. The clay-size fraction is montmorillonite, an alteration product of the glass.

The narrow outcrop belt of the Catahoula Formation, which is somewhat less than 300 ft (100 m) thick in Jasper County, extends from central Mississippi, through Louisiana and Texas parallel to the present coastline, and into eastern Mexico where it is not well studied.

Catahoula deposition is characterized by sporadic influxes of air-fall ash into low-gradient fluvial and coastal lake environments. Stratigraphic studies of the Catahoula Formation began as early as 1857, and the formation has since been studied by numerous stratigraphers and sedimentologists, including Hilgard, Penrose, Dumble, Veatch, and Deussen. Dumble (1918) gives a summary of this earlywork. Bailey (1926) named the lateral equivalent in the lower Texas coastal plain of south Texas theGueydan, and along with Renick (1936) established the Catahoula as a mid-Tertiary fluvial unit with abundant volcaniclastic material. A more recent summary of stratigraphic nomenclature is given in Sheldt (1976). Other recent studies of the Catahoula are concerned with petrology, geochemistry, and uranium ore genesis.
Geology of the Marathon Uplift, west Texas
Authors: McBride Earle F.
Published: November 2007

Roadcuts provide the only exposures of public access in the Marathon Uplift. However, roadcuts on U.S. 385 south of the town of Marathon and on U.S. 90 east of Marathon display spectacular features. Mileages to the first five stops in this guide are given from the junction of U.S. 385 south and U.S. 90 at the west edge of Marathon; mileages to the six remaining stops are from the junction of U.S. 385 north and U.S. 90 (Fig. 1).
Persimmon Gap in Big Bend National Park, Texas; Ouachita facies and Cretaceus cover deformed in a Laramide overthrust
Authors: Tauvers Peter R. , Muehlberger William R.
Published: November 2007

Persimmon Gap is unique in that the effects of three major Persimmon Gap. A wind gap that was part of the historic orogenies are exposed. A Paleozoic inlier features the southern- Comanche Trail crosses the southern Santiago Mountains at the most exposed thrust faults (Upper Ordovician over Lower Pennnorthern entrance to Big Bend National Park. The Persimmon sylvanian) of the Ouachita system in Texas. These rocks and the Gap site is 42 mi (68 km) south of Marathon, Texas, along U.S. Cretaceus cover (predominantly limestone) were involved in 385 (Fig. 1). The main outcrop is a prominent peak 0.5 mi (0.8 oblique overthrusting during Laramide left-slip transgression, lokm) east of the highway that can be reached easily by walking up tally creating a positive flower structure. Right-slip transtensional an arroyo into the hills (Fig. 2). Beware of cactus! Permission to faulting of the present cycle of Basin and Range deformation is walk off road should first be obtained at Persimmon Gap Ranger evident via downdropped fault blocks. The geologic history of the station 0.2 mi (0.3 km) south of the outcrop. The park has a region is dominated by repeated movements of basement-rooted nominal entrance fee. northwest-trending faults.
Classic “Kansas” cyclothems
Authors: Heckel Philip H.
Published: November 2007

This quadruple site (Fig. 1) illustrates typical examples of Kansas cyclothems of Pennsylvanian age.

Site 10: Iola and Wyandotte cyclothems (Figs. 2, 6). I-435 exit at Holliday Road, NE¼NW¼, Sec.6, T.12S., R.24E., Ed-wardsville 7½-minute Quadrangle, Johnson County, Kansas.

The best way to get to this section is to proceed south on I-435 from Kansas 32, cross the Kansas River and take the Holli-day Road exit around to the right, pulling off to park on the shoulder before meeting Holliday Road. The lower part of this section (up to the lower Argentine) is easily accessible on the east side of this ramp road, the upper part is accessible on the west side of this road, but requires more careful climbing.

Site 11: Swope and Dennis cyclothems (Figs. 2, 7). U.S. 69 roadcut by Jingo, SW¼SE¼, Sec.31, T.l8S., R.25E., New Lancaster 7½-minute Quadrangle, Miami County, Kansas.

This section is exposed continuously along the east side of U.S. 69 and the north side of a gravel section-line road that crosses U.S. 69, 13 mi (21 km) south of Kansas 68 (Louisburg) exit and 6 mi (9.6 km) north of Kansas 135 (LaCygne) exit. Park along the section-line road east of U.S. 69.

Site 12: Plattsburg cyclothem (Figs. 2, 8). Kansas 47 Altoona lower roadcut, near NW corner, Sec. 17, T.29S., R.16E., Altoona 7½-minute Quadrangle, Wilson County, Kansas.
The Anacacho Limestone of southwest Texas
Authors: Rodgers R. W.
Published: November 2007

The Anacacho Limestone represents an anomaly in the Gulfian-age rocks of Texas. Like the Austin Chalk that it unconformably overlies, the Anacacho is a limestone in a section dominated by terrigenous elastics and mudrocks; unlike the Austin Chalk (which is extensive throughout the margin of the Gulf Basin), the Anacacho is a small carbonate bank that extends less than 96 mi (160 km) along an east-west trend on the flanks of the Uvalde Salient. The formation thins perceptibly to the east toward San Antonio, where it is replaced by rocks of the Taylor Group. The formation reaches its maximum thickness on the flanks of the Uvalde Salient, and terminates abruptly at the western edge of the Anacacho Mountains. West of this termination the Anacacho is replaced by the Upson and San Miguel Formations.

From the Nueces River, west of the Uvalde Salient, westward to the Anacacho Mountains, the limestone outcrop is continuous for approximately 28 mi (46 km). The width of the outcrop varies from 2.4 mi (4 km) to 9 mi (15 km). East of the Uvalde Salient, outcrops of the Anacacho Limestone are discontinuous and scattered. Much of the section is either covered by alluvium or is lost along faults of the Balcones Fault Zone (Bureau of Economic Geology, 1974). This section, from Blanco Creek eastward to San Antonio, is approximately 60 mi (100 km) in length. However, outcrops in this section are limited in length from a few miles to several hundred feet. Exposures are mostly along
West Atchison Drift Section
Authors: Aber James S.
Published: November 2007

A series of long-studied exposures of glacial sediments is found immediately west of the city of Atchison, Atchison County, Kansas, along the south side of White Clay Creek in Sec. 2, 10, 1l, T.6S., R.20E. (Fig. 1). The stream cuts are readily accessible by foot from U.S. 59, which parallels the north side of White Clay Creek. It is advisable to ask local residents for permission to cross private property to reach the stream cuts.
Bunker Hill section of Upper Cretaceus rocks in Kansas
Authors: Hattin Donald E. , Twiss Page C.
Published: November 2007

The Bunker Hill section of the upper part of the Graneros Shale, Greenhorn Limestone, and of the lower part of the Carlile Shale is along the east side of Bunker Hill-Luray Road (Kansas FAS 47) about 4.5 mi (7.2 km) north of 1-70, along the center of the west line of Sec.18, T.13S., R.12W., Russell County, Kansas (Fig. 1). The top of the section is at the intersection with the unpaved side road to the east at an elevation of 1,790 ft (546 m); the base of the section is about 0.5 mi (0.8 km) north at an elevation of about 1,700 ft (518 m). Safest parking is on the side road near the top of the section (Fig. 1T).

Vehicles traveling on 1-70 should exit at the Bunker Hill exit (exit 193) and travel 4.5 mi (7.2 km) north through Bunker Hill to Sec. 18. The Bunker Hill exit is about 9 mi (14 km) east of Russell.
Rocktown channel in Dakota Formation of central Kansas
Authors: Twiss Page C.
Published: November 2007

The Rocktown channel sandstone of the Upper Dakota Formation is exposed on both sides of a road cut on Kansas 232, about 4.1 mi (6.6 km) north of 1-70 in the NW¼SE¼ Sec.19, T.12S., R.10W., Lincoln County, Kansas (Fig. 1). Vehicles traveling on 1-70 should exit at the Wilson and Wilson Reservoir exit (exit 206) and travel north on Kansas 232 toward Wilson Reservoir.
Ogallala Formation (Miocene), western Kansas
Authors: Gutentag Edwin D.
Published: November 2007

The area in the vicinity of Lake Scott State Park, Scott County, Kansas (Fig. 1), contains excellent outcrops of the Ogal-lala Formation. One of the best vertically continuous exposures is in the west side of the roadcut at the ridge called Devils Backbone, which is located in the NW¼, NE¼, Sec.25, T.16S., R.32W. This section is described in Table 1 and diagrammatically sketched in Figure 2.
Mine 19 geologic section, Pittsburg and Midway Coal Mining Company, Cherokee County, Kansas
Authors: Brady Lawrence L.
Published: November 2007

This site is an abandoned strip mine just south of West Mineral in northwest Cherokee County, in extreme southeastern Kansas. It can be reached most easily by traveling 5 mi (8 km) west from Kansas 7 on Kansas 102 to West Mineral and following local roads to the exposures shown in Figure 1.
Evaporates and red beds in Roman Nose State Park, northwest Oklahoma
Authors: Johnson Kenneth S.
Published: November 2007

Roman Nose State Park comprises 540 acres (219 hectares) of public lands where layers of Permian gypsum, dolomite, and shale are well exposed and where fresh water flows from three natural springs. The site is in the central part of Blaine County, northwestern Oklahoma (Fig. 1), located about 6 mi (10 km) north of Watonga, in Secs. 23 and 24, T.17N., R.12W. The park allows free access at all times and provides picnic and camping facilities; the park also contains a resort lodge, meals, and cottages. For information and access to springs and other areas partially closed during winter months (October 1 till early April), contact the Park Superintendent, Roman Nose State Park, Route 1, Box 2-2, Watonga, OK 73772 (telephone: 405/623-4215). The area is on the Watonga Lake 7½-minute Quadrangle.
Carbonate platform facies of the Morrowan Series (Lower Pennsylvanian), northeastern Oklahoma and northwestern Arkansas
Authors: Sutherland Patrick K. , Manger Walter L.
Published: November 2007

The localities described here form a transect from the Arkansas River, near Webbers Falls, Muskogee County, eastern Oklahoma, eastward to the Oklahoma/Arkansas boundary area near Evansville, Arkansas (Fig. 1). Detailed location data for each stop on the transect are given in the text.
Some aspects of the geology of Zodletone Mountain, southwestern Oklahoma
Authors: Donovan R.N. , Younger P. , Ditzell C.
Published: November 2007

Zodletone Mountain, a 250-ft-high (76 m) eminence in Kiowa County, southern Oklahoma, constitutes the northernmost member of the Slick Hills Range and rises 1,649 ft (500 m) above sea level (SW¼SW¼ Sec.9, T.6N., R.14W. Saddle Mountain 15-minute Quadrangle, Oklahoma). The best approach to the mountain is by following Oklahoma 58 south from Carnegie for 7 mi (11 km). At this point turn west along an unpaved section road for 3 mi (4.8 km), then south for 0.5 mi (800 m) to a white two-storied farmhouse, which is the home of Mr. Don Trobe (Fig. 1). Obtain permission to visit here. (Mr. Trobe, like everyone else hereabouts, has been very supportive of geologists. However, no smoking and no litter, please.) About 0.5 mi (0.8 km) south of Mr. Trobe—s home, turn west along another section road and drive 1.7 mi (2.7 km) to a silver gate at SE¼SW¼Sec.16, T.6N., R.14W. From here a fair-weather track runs north to the northeast side of Zodletone Mountain. Follow this track to its termination, park, and walk (but beware of rattlesnakes).
Max Meadows tectonic breccia at Pepper, Virginia
Authors: Schultz Arthur P.
Published: November 2007

Outcrops of extensive Max Meadows tectonic breccia are along the bluffs overlooking New River at Pepper, Virginia (Fig. 1). A few feet (m) northeast of the New River bridge on Virginia 114 turn north into a dirt road. Parkin the wide area just onto the dirt road and do not block the driveway to the private house. Do not drive to the outcrops on the dirt road which is a railroad right of way. Walk northeast about 1,000 ft (300 m) to the railroad tracks along the dirt road.
Chestnut Ridge fenster
Authors: Milici Robert C.
Published: November 2007

The Chestnut Ridge fenster area is located southeast of Ewing, Lee County, Virginia, in parts of the Coleman Gap, Ewing and Back Valley 7½-minute Quadrangles (Fig. 1). From Ewing, Virginia, proceed northeast 1.7 mi (2.7 km) on U.S. 58, turn right on Lee County road 744; proceed 1.1 mi (1.8 km) toroad fork, take right fork. (Route has been on rocks of the Knox Group; outcrops of the Maynardville Formation are exposed on left side of road 0.7 mi [1.1 km] south of road fork.) The fenster is exposed in the road and adajcent fields 1.0 mi (1.6 km) south of the road fork 0.3 mi (0.5 km) beyond the Maynardville Formation exposure.
Thorn Hill
Authors: Byerly Don W. , Walker K. R. , Diehl W. W. , Ghazizadeh M. , Johnson R. E. , Lutz C. T. , Schoner A. K. , Simmons W. A. , Simonson J.C.B. , Weber L. J. , Wedekind J. E.
Published: November 2007

The “Thorn Hill Section” is an amazingly complete and well exposed section of rocks that has served at least four generations of geologists as a reference for early Cambrian through early Carboniferous stratigraphy of the Southern Appalachians. Eastward from War Ridge along 8.8 mi (14 km) of U.S.25-E, across Clinch Mountain to Poor Valley Ridge, Grainger County, Tennessee, virtually every unit between the Rome and the Grainger formations in the Southern Appalachians is exposed in the 10,912 ft (3,326 m) thick sectio (Fig. 1). The section is bounded by two major thrust faults-the Copper Creekfault and the Saltville fault; the Rome Formation is the hanging wall forboth faults. Most of the section is embraced by the Avondale, 7½-minute topographic quadrangle with the remainder on the Dutch Valley, 7½-minute Quadrangle. The stratigraphic descriptions given here are synopses from Walker (1985). The stratigraphy here represents a westward thinning edge of a thick wedge dof Paleozoic sedimentary rocks whose history is recorded in three stratigraphic sequences bounded by unconformities of regional extent (Fig. 2). Sequence I embraces Cambrian through Early Ordovician, Sequence II the middle Ordovician through Early Devonian, and Sequence III Late Devonian through Early Mississippian.

The stratigraphic descriptions given here are synopses from Walker (1985). The stratigraphy here represents a westward thinning edge of a thick wedge of Paleozoic sedimentary rocks whose history is recorded in three stratigraphic sequences bounded by unconformities of regional extent (Fig. 2). Sequence I embraces Cambrian through Early Ordovician, Sequence II the middle Ordovician through Early
Saltville fault at Sharp Gap, Knoxville, Tennessee
Authors: Hatcher Robert D.
Published: November 2007

Sharp Gap is located on the north side of Frontage Road parallel to I-275 in Sharp Gap, which passes through Sharp Ridge, Knoxville, Tennessee (Fig. 1). It also includes exposure on the south side of Sharp Gap at road level off the side of I-275, Knox County, Tennessee, Knoxville and Fountain City 7½-minute Quadrangles, Tennessee (Cattermole, 1958, 1966).
Middle Ordovician shelf-edge skeletal sand-bank, organic build-ups, and quartz-sand-waves of the Holston and Chapman Ridge Formations near Knoxville, Tennessee
Authors: Walker Kenneth R.
Published: November 2007

This set of three outcrops is located south of the city of Knoxville, on the east side of Alcoa Highway (U.S. 129) one mi (1.6 km) south of the James E. Karnes Bridge over the Tennessee River (Fort Loudon Lake). The northernmost of the three outcrops is directly across Alcoa Highway from the Naval Reserve Station. The locality is in the southern part of the Knoxville 7½-minute Quadrangle (Fig. 1). The site is easily accessible, although Alcoa Highway is heavily traveled, and you are cautioned to cross the highway with great care. Parking is available on the east side of the highway just south of the Naval Reserve Station.
The Coosa deformed belt, thin imbricate thrust slices in the Appalachian fold-thrust belt in Alabama
Authors: Thomas William A. , Drahovzal James A.
Published: November 2007

A deep road cut on Alabama 77 (sec. 29, T.14S., R.6E.) near Ohatchee, Calhoun County, Alabama (Fig. 1), provides an exceptionally good view of imbricate thrust faults in the frontal tier of the Coosa deformed belt.
Sequatchie anticline, the northwesternmost structure of the Appalachian fold-thrust belt in Alabama
Authors: Thomas William A.
Published: November 2007

Two stops at Blount Springs, Blount County, Alabama (Fig. 1), provide traverses of parts of the Sequatchie anticline on the Blount Springs culmination. Blount Springs is on U.S. 31 approximately 4 mi (6 km) east of I-65. Interchange 287 on I-65 has only a northbound exit and a southbound entrance connecting with U.S. 31. Interchange 289 (north of Interchange 287 at U.S. 31) on I-65 has exits and entrances both northbound and southbound, and provides access to Blount Springs via Blount County Road 5.
Birmingham anticlinorium in the Appalachian fold-thrust belt, basement fault system, synsedimentary structure, and thrust ramp
Authors: Thomas William A. , Bearce Denny N.
Published: November 2007

At Birmingham, in the central part of the Appalachian foldthrust belt in Alabama, the Birmingham anticlinorium is associated with a large-scale ramp on the regional decollement and includes the Opossum Valley and Jones Valley thrust sheets (Figs. 1,2, and 3). The southeast limb of the asymmetric anticlinorium in the hanging wall of the Jones Valley fault dips gently southeast into the Cahaba synclinorium (Locality 42); the northwest limb in the footwall of the Opossum Valley fault is overturned and dips steeply southeast (Locality 43) (Fig. 3). The youngest rocks in the anticlinorium are Early Pennsylvanian, indicating thrusting during the Alleghanian orogeny. The Middle Cambrian Conasauga Formation is the oldest unit in the hanging walls of the Opossum Valley and Jones Valley thrust faults, thus indicating the stratigraphic level of the regional decollement (Fig. 3).

The Appalachian fold-thrust belt in Alabama may be divided into three domains (Thomas, 1982). The Birmingham anticlinorium is the most northwesterly structure in the central domain, which is characterized by large-scale thrust ramps and associated folds having structural relief of more than 15,000 ft (4,500 m). In contrast, the northwestern domain is characterized by broad, flat-bottomed synclines and narrow, asymmetric anticline having relief of less than 10,000 ft (3,000 m). The southeastern domain is characterized by broad, low-angle, multiplelevel thrust sheets. Amplitude of structures within the central domain, as indicated by dip angles on fold limbs and by preserved thickness of Paleozoic rocks in the synclines, defines a minimum depth to basement of approximately 23,000 ft
Shores Complex and Mélange in the central Virginia Piedmont
Authors: Brown William Randall
Published: November 2007

A 1 mi (l.6km) section just east of Shores Station on the north side of the James River, Fluvanna County, Arvonia 7½-minute quadrangle (Fig. 1). Exposure is along a rough gravel Chesapeake and Ohio Railroad access road beside the tracks. It is a private road and no questions are asked of small groups, but large groups should get permission from: Chessie System Railroad, Division Office, P.O. Box 1254, Richmond, Virginia 23210, phone (804)-226-7400.
Ophiolite in the Lynchburg Group near Rocky Mount, Virginia
Authors: Conley James F.
Published: November 2007

The city of Rocky Mount, Virginia is located in Franklin County in the southwestern Piedmont of Virginia. It is situated on U.S. 220 about halfway between the cities of Roanoke and Martinsville (Fig. 1).
Linville Falls fault at Linville Falls, North Carolina
Authors: Hatcher Robert D. , Butler J. Robert
Published: November 2007

One half mi (1 km) south of the Linville Falls parking area off Blue Ridge Parkway east of the town of Linville Falls, North Carolina, Linville Falls 7½-minute Quadrangle, North Carolina (Fig. 1). This locality is within the Blue Ridge Parkway National Park. Consequently, the collecting of samples and breaking of rocks is prohibited. The actual fault exposure is about 100 yd (90 m) above the falls at the end of the trail from the parking lot and is in the area indicated by a sign to not enter because of the dangerous rapids and the river. This area can be entered by walking carefully.
The Kings Mountain belt and spodumene Pegmatite District, Cherokee and York Counties, South Carolina, and Cleveland County, North Carolina
Authors: Horton J. Wright , Butler J. Robert
Published: November 2007

The Kings Mountain belt and spodumene Pegmatite district are located in Cherokee and York Counties, South Carolina, and Cleveland County, North Carolina, south of Kings Mountain, North Carolina (Fig. 1). This area includes the most complete stratigraphic section, the most productive mineral deposits, and the most intensively studied parts of the belt.
Middle Ordovician High Bridge Group and Kentucky River fault System in central Kentucky
Authors: Kuhnhenn Gary L. , Haney Donald C.
Published: November 2007

The Middle Ordovician High Bridge Group and Kentucky River fault system are exposed along the new part of U.S. 27 just north and south of the Kentucky River near the village of Camp Nelson, Kentucky, in the southwestern quarter of the southwestern section of the Little Hickman 7½-minute quadrangle (Fig. 1). There is ample room to safely park along roadcuts here, but caution is strongly urged because of the common occurrence of heavy traffic. Stop 4 is located on the east side of “Old U.S. 27” along an unnamed road just north of the river and below stop 1.