U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Map 3172

Geologic Cross Section C–C’ Through the Appalachian Basin 

From Erie County, North-Central Ohio, to the Valley and Ridge 

Province, Bedford County, South-Central Pennsylvania

By Robert T. Ryder, Michael H. Trippi, Christopher S. Swezey, Robert D. Crangle, Jr., Rebecca S. Hope, 

Elisabeth L. Rowan, and Erika E. Lentz
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2012

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Suggested citation:

Ryder, R.T., Trippi, M.H., Swezey, C.S. Crangle, R.D., Jr., Hope, R.S., Rowan, E.L., and Lentz, E.E., 2012, Geologic cross section C–C’ through the Appalachian basin from 

Erie County, north-central Ohio, to the Valley and Ridge province, Bedford County, south-central Pennsylvania: U.S. Geological Survey Scientific Investigations Map 3172, 2 

sheets, 70-p. pamphlet. (Also available at http://pubs.usgs.gov/sim/3172/.)

ISBN 978–1–4113–3277–5
ii

Contents

Introduction......................................................................................................................................................................................................................................1

Construction of the Cross Section ...............................................................................................................................................................................................1

Structural Framework ....................................................................................................................................................................................................................5

Basement Rocks and Associated Structures ...................................................................................................................................................................5

Thin-Skinned Structures.......................................................................................................................................................................................................7

Stratigraphic Framework...............................................................................................................................................................................................................9

Lower Cambrian to Upper Ordovician Siliciclastic and Carbonate Strata.................................................................................................................10

Upper Ordovician to Lower Silurian Siliciclastic Strata................................................................................................................................................14

Lower Silurian to Middle Devonian Carbonate and Evaporite Strata.........................................................................................................................16

Middle Devonian to Lower Mississippian Siliciclastic Strata......................................................................................................................................18

Upper Mississippian Carbonate Strata............................................................................................................................................................................20

Upper Mississippian, Pennsylvanian, and Permian Siliciclastic Strata.....................................................................................................................21

Acknowledgments........................................................................................................................................................................................................................22

References Cited...........................................................................................................................................................................................................................22

Appendix A.—Table Summarizing Drill Holes, Stratigraphic Units, and Depths of Stratigraphic Units in Cross Section C–C’.................................35

Appendix B.—Scale, Units, and Depths for Gamma-Ray Logging Runs.............................................................................................................................69

Figures

[on sheets 1 and 2]

1. Map of Ohio, West Virginia, Pennsylvania, and adjoining States showing location of cross section C–C’ and selected 

tectonic features.

2. Correlation chart of Paleozoic rocks along cross section C–C’ in Ohio, northernmost West Virginia, and Pennsylvania.

3. Diagram showing major footwall ramps (thrust faults) and zones of bedding-plane detachment in the eastern part of 

cross section C–C’.
iii

Tables

1. Drill holes used to construct cross section C–C’ .....................................................................................................................................................2
Geologic Cross Section C–C′ Through the Appalachian Basin From Erie County, 

North-Central Ohio, to the Valley and Ridge Province, Bedford County, SouthCentral Pennsylvania

By Robert T. Ryder, Michael H. Trippi, Christopher S. Swezey, Robert D. Crangle, Jr., Rebecca S. Hope, Elisabeth L. Rowan, and Erika E. Lentz

Introduction

Geologic cross section C–C′ is the third in a series 

of cross sections constructed by the U.S. Geological 

Survey (USGS) to document and improve understanding of the geologic framework and petroleum systems 

of the Appalachian basin. Cross section C–C′ provides 

a regional view of the structural and stratigraphic 

framework of the Appalachian basin from north-central 

Ohio to the Valley and Ridge province in south-central 

Pennsylvania, a distance of approximately 260 miles 

(mi) (fig. 1). This cross section is a companion to cross 

sections E–E′ and D–D′ (Ryder and others, 2008, 2009) 

that are located about 50 to 125 mi and 25 to 50 mi, 

respectively, to the southwest (fig. 1). Cross sections 

C–C′, D–D′, and E–E′ update earlier geologic cross 

sections through the central Appalachian basin by 

Renfro and Feray (1970), Bennison (1976, 1978), Bally 

and Snelson (1980), and a stratigraphic cross section by 

Colton (1970). Although other published cross sections through parts of the basin show more structural 

detail (for example, de Witt, 1974; Berg and others, 

1980; Faill, 1987; Nickelsen, 1988; Shumaker, 2002; 

Slucher and others, 2006) and stratigraphic detail (for 

example, Piotrowski and Krajewski, 1977a,b; Ryder 

and others, 1992; de Witt and others, 1993; Hettinger, 

2001; Riley and others, 2006), these other cross sections are of more limited extent geographically and (or) 

stratigraphically.

Cross section C–C′ contains much information that is useful for evaluating energy resources in 

the Appalachian basin. Although specific petroleum 

systems are not identified on the cross section, many 

of their key elements (such as source rocks, reservoir 

rocks, seals, and traps) can be inferred from lithologic 

units, unconformities, and geologic structures shown on 

the cross section. Other aspects of petroleum systems 

(such as the timing of petroleum generation and preferred migration pathways) may be evaluated by burial 

history, thermal history, and fluid flow models based on 

what is shown on the cross section. Cross section C–C′

also provides a general framework (stratigraphic units 

and general rock types) for the coal-bearing section, 

although the cross section lacks the detail to illustrate 

key elements of coal systems (such as paleoclimate, 

coal quality, and coal rank). In addition, cross section 

C–C′ may be used as a reconnaissance tool to identify 

plausible geologic structures and strata for the subsurface storage of liquid waste (for example, Colton, 

1961; Lloyd and Reid, 1990) or for the sequestration of 

carbon dioxide (for example, Smith and others, 2002; 

Lucier and others, 2006).

Construction of the Cross Section

Cross section C–C′ is oriented northwest-southeast, approximately normal to the structural grain of the 

region. Several abrupt bends in the section, however, 

are required to accommodate key drill holes that penetrate the entire section of Paleozoic sedimentary rocks. 

Cross section C–C′ follows the general line of section 

used by Ryder and others (1992) in their stratigraphic 

study of Cambrian and Ordovician rocks, but four 

drill holes have been added (two at the northwestern 

end and two near the middle) and two drill holes have 

been omitted at and near the southeastern end (fig. 1; 

table 1).

Cross section C–C′ is based on geological and 

geophysical data from 11 deep drill holes, several of 

which penetrate the Paleozoic sedimentary rocks of 

the basin and bottom in Mesoproterozoic crystalline 

basement rocks of the Grenville province. The locations of the tops of each stratigraphic unit penetrated 

in the 11 deep drill holes were converted from depth in 

feet (ft) below the kelly bushing (KB) to depth below 

ground level (GL), and then were plotted on the cross 

section with respect to mean sea level (MSL). Detailed 

depth information for the tops of the stratigraphic units 

in each well is reported in appendix A. In addition 
2 Geologic Cross Section C–C’ Through the Appalachian Basin

Table 1. Drill holes used to construct cross section C–C’.—Continued

[Drill-hole locations are shown in figure 1. Source of all lithologic logs is Geological Sample Log Company, Pittsburgh, Pa. Abbreviations are as follows: Co., County; min, minute; NA, not available; No., Number; 

Pa., Pennsylvania; W. Va., West Virginia]

Drill 

hole 

number

Name used in text Location American Petroleum 

Institute number

Latitude 

(decimal 

degrees)

Longitude 

(decimal 

degrees)

Lithologic 

log

Cored intervals 

(in feet) and 

stratigraphic unit

Total 

depth 

(in feet)

Age of oldest 

rocks drilled 

(stratigraphic unit)

Ohio

1 Sun Oil Co. No. 1 KrysikWakefieldFlorence Township, Erie Co., Ohio 

(Kipton, Ohio, 7.5-min quadrangle)

34–043–20011 41.304 -82.350 Yes NA 4,463 Mesoproterozoic 

(metamorphic and 

igneous rock).

2 East Ohio Gas No. 1 A & A 

Born

Henrietta Township, Lorain Co., 

Ohio (Kipton, Ohio, 7.5-min 

quadrangle)

34–093–20794 41.289 -82.321 Yes NA 4,591 Mesoproterozoic 

(metamorphic and 

igneous rock).

3 Wiser Oil No. 1–A F.L. Smith 

Estate

Hinckley Township, Medina Co., 

Ohio (West Richfield, Ohio, 7.5-

min quadrangle)

34–103–21143 41.229 -81.703 Yes 5,760–5,844, Wells Creek 

formation, Knox Dolomite 

(Copper Ridge dolomite), 

Knox Dolomite (B zone 

and Krysik sandstone); 

5,860–5,890, Knox Dolomite (B zone and Krysik 

sandstone)

7,040 Mesoproterozoic 

(metamorphic and 

igneous rock).

4 Belden & Blake Co., Limited 

Partnership #9 No. 1–381 

B. Westfall

Marlboro Township, Stark Co., 

Ohio (Hartville, Ohio, 7.5-min 

quadrangle)

34–151–21081 40.952 -81.263 Yes NA 7,961 Late Cambrian 

(Maryville Limestone of Conasauga 

Group).

5 Management Control No. 3 

Frank Murray

Hanover Township, Columbiana 

Co., Ohio (Lisbon, Ohio, 7.5-min 

quadrangle)

34–029–20648 40.786 -80.870 Yes NA 10,242 Late Cambrian (Mount 

Simon Sandstone).

West Virginia

6 Humble Oil No. 1 

S. Minesinger

Clay District, Hancock Co., W. Va.-

Ohio-Pa. (East Liverpool South, 

W. Va., 7.5-min quadrangle)

47–029–00080 40.540 -80.556 Yes 6,315–6,368; Lockport 

Dolomite

10,387 Early Ordovician 

(Beekmantown 

Dolomite).
Construction of the Cross Section 3

Table 1. Drill holes used to construct cross section C–C’.—Continued

[Drill-hole locations are shown in figure 1. Source of all lithologic logs is Geological Sample Log Company, Pittsburgh, Pa. Abbreviations are as follows: Co., County; min, minute; NA, not available; No., Number; 

Pa., Pennsylvania; W. Va., West Virginia]

Drill 

hole 

number

Name used in text Location American Petroleum 

Institute number

Latitude 

(decimal 

degrees)

Longitude 

(decimal 

degrees)

Lithologic 

log

Cored intervals 

(in feet) and 

stratigraphic unit

Total 

depth 

(in feet)

Age of oldest 

rocks drilled 

(stratigraphic unit)

Pennsylvania

7 St. Joe Petroleum Corp. No. 1 

Richard J. Ashcroft

Greene Township, Beaver Co., Pa. 

(Hookstown, Pa., 7.5-min quadrangle)

37–007–20060 40.602 -80.434 Yes NA 7,590 Late Ordovician 

(Queenston Shale).

8 William E. Snee, et al No. 1 

E.C. Ricks

Wharton Township, Fayette Co., 

Pa. (Brownfield, Pa., 7.5-min 

quadrangle)

37–051–20056 39.843 -79.654 Yes NA 12,041 Late Ordovician(?) 

(Tuscarora 

Formation-Juniata 

Formation transition 

zone).

9 Amoco Producing Co. No. 1 

Leonard Svetz

Middlecreek Township, Somerset 

Co., Pa. (Kingwood, Pa., 7.5-min 

quadrangle)

37-111-20045 39.978 -79.334 Yes NA 21,460 Late Cambrian (lower 

sandy member of 

Gatesburg Formation).

10 Kerr-McGee Corp. No. 1 

Schellsburg

Napier Township, Bedford Co., Pa. 

(Bedford, Pa., 7.5-min quadrangle)

37-009-20034 40.104 -78.616 Yes NA 11,850 Late Cambrian (upper 

sandy member of 

Gatesburg Formation).

11 Atlantic Richfield Co. No. 1 

Fred Steele

Snake Spring Township, Bedford Co., 

Pa. (Everett West, Pa., 7.5-min 

quadrangle)

37-009-20060 40.016 -78.422 Yes 14,728–14,758, upper sandy 

member of Gatesburg 

Formation

15,500 Early to Middle Cambrian (Waynesboro 

Formation).
4 Geologic Cross Section C–C’ Through the Appalachian Basin

to the 11 deep drill holes used to construct the cross 

section (table 1), some of the details of middle and 

upper Paleozoic stratigraphy and structure along cross 

section C–C′ were obtained from 13 supplementary 

drill holes. These supplementary drill holes are located 

on the cross section as follows: (1) two drill holes 

between drill holes 4 and 5 in Ohio; (2) two drill holes 

between drill holes 5 and 6 in Ohio; (3) three drill holes 

between drill holes 7 and 8 in southwestern Pennsylvania (Harper and Laughrey, 1987); (4) one drill hole 

between drill holes 8 and 9 in southwestern Pennsylvania; and (5) five drill holes between drill holes 9 and 10 

in south-central Pennsylvania.

The correlation of stratigraphic intervals between 

drill holes was based on a variety of geophysical (wireline) and lithologic logs. The most commonly used geophysical logs were the gamma ray-neutron and gamma 

ray-density log suites (Trippi and Crangle, 2009), 

whereas the most commonly used lithologic logs were 

those produced by the Geological Sample Log Company (table 1). Gamma-ray logs used for correlations 

were digitized as Log ASCII files (LAS), converted to 

graphic images, and then plotted next to their respective 

drill holes (Trippi and Crangle, 2009). The lithology 

assigned to each stratigraphic interval was simplified to 

just a few rock types and lithologic modifiers.

The data from the drill holes were supplemented 

by data about bedrock geology and topography. For 

example, some details of the Pennsylvanian stratigraphy in eastern Ohio were obtained from bedrock 

geologic maps by Larsen and Rea (1990), Slucher and 

Larsen (1990, 1996a,b), Caudill and Slucher (1991, 

revised 1996), Larsen and Slucher (1996), Slucher 

(1996a,b), and Swinford and Shrake (1996 a,b). Similar 

details of the Pennsylvanian stratigraphy in northernmost West Virginia were obtained from the geologic 

map by Grimsley (1907). Also, where applicable, 

selected stratigraphic units in the cross section were 

tied to correlative outcropping units using the geologic 

maps of Ohio (Slucher and others, 2006) and Pennsylvania (Berg and others, 1980) and, locally, using 

quadrangle maps by the Ohio Division of Geological Survey (for example, Slucher and Larsen, 1996a) 

and by the Pennsylvania Bureau of Topographic and 

Geologic Survey (for example, Flint, 1965; Wagner, 

Craft, and others, 1975). The topographic profile for the 

cross section was created from a Shuttle Radar Topography Mission (SRTM) 90-m-grid digital elevation 

model (DEM) for parts of Ohio, Pennsylvania, West 

Virginia, Maryland, and Virginia (Consultative Group 

on International Agricultural Research—Consortium 

for Spatial Information, 2011). This topographic profile 

is approximate and should not be used to determine 

accurate surface elevations.

Although some correlations shown on section 

C–C′ are based on our own interpretations, many correlations are adopted or modified from previous publications, and stratigraphic nomenclature follows existing 

terminology wherever possible. Useful references for 

stratigraphic correlations and (or) nomenclature include 

the following: Colton (1970); Berg and others (1983), 

Patchen and others (1985), Milici and de Witt (1988), 

Swezey (2002), and Slucher (2004) for the entire Paleozoic section; Wagner (1966), Janssens (1973), Riley 

and Baranoski (1991a,b), Ryder and others (1992), 

Wickstrom and others (1992), Riley and others (1993, 

2006), Laughrey and others (2003), and Harris and others (2004) for Cambrian and Ordovician rocks; Clifford 

(1973), Janssens (1977), Smosna and others (1977), 

Ryder (2000, 2004), and Hettinger (2001) for Silurian 

rocks; Piotrowski and Krajewski (1977a,b), Piotrowski 

and Harper (1979), Majchszak (1980a,b), de Witt 

and others (1993), Harper (1999), Harper and others 

(1999), and Filer (2002, 2003) for Devonian rocks; and 

Berryhill and Swanson (1962), Berryhill and others, 

(1971), Wagner, Craft, and others (1975), Edmunds and 

others (1979, 1999), Harper and Laughrey (1987), Berg 

(1999), Brezinski (1999), and Stamm (2004) for Mississippian and Pennsylvanian rocks. A correlation chart 

for all of the stratigraphic units identified along section 

C–C′ is shown in figure 2.

Only selected unconformities are shown in cross 

section C–C′. The regional unconformities shown on 

section C–C′ and in figure 2 include (1) the Middle 

Ordovician Knox unconformity (Harris and Repetski, 

1982; Mussman and others, 1988), (2) the Upper Ordovician to Lower Silurian Cherokee unconformity (Dennison and Head, 1975; Hettinger, 2001), (3) the Middle 

to Upper Devonian unconformity (de Witt and others, 

1993), (4) the Middle Mississippian sub-Loyalhanna 

unconformity (Harper and Laughrey, 1987; Brezinski, 

1999), and (5) the Lower Pennsylvanian unconformity 

(Edmunds and others, 1979; Rice and Schwietering, 

1988; Beuthin, 1994). The correlation of these unconformities with the North American sequences of Sloss 

(1988) is shown on figure 2 and by Swezey (2002).

Basement-involved structures along cross section C–C′ were modified from structure-contour maps 

by Shumaker (1996), Baranoski (2002), and locally 

from interpretations of seismic data by Scanlin and 

Engelder (2003) and Kulander and Ryder (2005). 

High-amplitude, complex, thin-skinned ramp anticlines 

(Schellsburg dome, Wills Mountain, and Evitts Mountain) were compiled on section C–C′ from interpretations by Knowles (1966), Gwinn (1970), and Berg and 

others (1980). The Schellsburg dome in Pennsylvania 

is an extension of the Deer Park anticline in Maryland 

(Shumaker and Wilson, 1985), and it is the first anticline west of the Allegheny structural front (fig. 1). In 

contrast, the Wills Mountain and Evitts Mountain anticlines are the first two anticlines east of the Allegheny 

structural front. Low-amplitude, structurally complex, 

thin-skinned anticlines west of the Allegheny structural front (Negro Mountain, Laurel Hill, and Chestnut 

Ridge) are based on selected drill holes and interpretations by Berg and others (1980), Shumaker (2002), 

and Scanlin and Engelder (2003). The Chestnut Ridge 

anticline, which was drilled by well 8, marks the western limit of the major thin-skinned anticlines shown 

on the cross section. Low-amplitude anticlines located 

northwest of the Chestnut Ridge anticline (for example, 

Amity and Belle Vernon) are defined on section C–C′
Structural Framework 5

by selected drill holes and structure-contour maps on 

the top of the Devonian Ridgeley Sandstone (Cate, 

1961) and on top of selected Pennsylvanian coal beds 

(Hickok and Moyer, 1940; Wagner, Heyman, and others, 1975; Dodge, 1985; Shaulis, 1985; Skema, 1987). 

In Ohio, the homoclinal regional dip on section C–C′

and accompanying local faults are defined by structurecontour maps on the top of the Devonian Berea Sandstone and Onondaga Limestone (Gray, 1982a,b).

Structural Framework

The Wills Mountain anticline marks the western 

margin of the Valley and Ridge province (fig. 1), where 

a thick panel of Cambrian to Ordovician carbonate rocks was decoupled from underlying strata and 

was thrust about 2 mi westward up a major tectonic 

(footwall) ramp. This ramp connected the basal zone of 

detachment (footwall flat) in the Cambrian Waynesboro 

Formation with higher zones of detachment (hangingwall flat) in the Upper Ordovician Antes Shale, Silurian 

Wills Creek Formation, and Devonian Marcellus Formation (thrust terminology from McClay, 1992). The 

net shortening in the Wills Mountain anticline is about 

6 to 7 mi when folding and secondary thrust faulting 

are accounted for. A net structural relief of about 1.5 

mi (8,000 ft) was created by the duplicated Cambrian 

Warrior Formation in the anticline. Following Gwinn 

(1970), Rodgers (1970), and Faill (1998) (and using the 

terminology therein), the juncture between the western 

limb of the Wills Mountain anticline and the adjoining eastern limb of the Schellsburg dome is defined as 

the Allegheny structural front, which is the structural 

feature that separates the Valley and Ridge province 

to the east from the Appalachian Plateau province to 

the west (figs. 1, 3). The Allegheny structural front as 

recognized in south-central Pennsylvania differs from 

the traditional Allegheny structural front as recognized 

in Maryland and West Virginia (for example, Kulander 

and Dean, 1986), where steeply dipping lower Paleozoic carbonate and siliciclastic rocks of the western 

limb of the Wills Mountain anticline are juxtaposed 

directly against less deformed upper Paleozoic rocks 

of the Appalachian Plateau province rather than against 

rocks of the intervening Schellsburg dome.

The Schellsburg dome experienced a lesser 

amount of lateral shortening than the Wills Mountain 

anticline. For example, the thick allochthonous panel of 

Cambrian to Ordovician carbonate rocks in the Schellsburg dome (that was decoupled from the underlying 

strata and thrust about 1.5 mi westward up a footwall 

ramp and over a parautochthonous panel of Cambrian 

to Ordovician carbonate rocks) displays a net shortening of about 4 mi. Together, the Schellsburg dome and 

Wills Mountain anticline in south-central Pennsylvania 

show about the same amount of net lateral shortening as the Deer Park and Wills Mountain anticlines 

combined in Maryland and West Virginia. The footwall 

ramp of the Schellsburg dome, which is shown on the 

easternmost part of the cross section beneath drill hole 

10, connects the basal zone of detachment (footwall 

flat) in the Cambrian Waynesboro Formation with a 

higher zone of detachment (hangingwall flat) in the 

Ordovician Antes Shale. As a result of this lateral shortening, a net structural relief of about 1.4 mi (7,500 ft) 

was created by the duplicated Warrior Formation in the 

anticline. This interpretation of the Schellsburg dome 

structure, where the hangingwall flat occurs in the 

Antes Shale (fig. 3), follows Gwinn (1970). An alternate interpretation of the structure is shown by Berg 

and others (1980), where the hangingwall flat occurs in 

the Silurian Wills Creek Formation and Salina Group.

Basement-involved and thin-skinned structures 

(terminology from Rodgers, 1963) are shown on cross 

section C–C′ and their geometry, style, and timing are 

briefly discussed below. A more detailed treatment of 

structural styles and patterns that characterize the central Appalachian basin is presented by Faill (1998) and 

Scanlin and Engelder (2003). The basement structures 

are largely extensional, and several of them may have 

evolved during the Neoproterozoic to earliest Cambrian rifting of the eastern continental margin of North 

America (Rankin and others, 1989; Thomas, 1991). 

This rifting event was followed by the opening of the 

Iapetus Ocean and the construction of a passive margin 

along the eastern margin of North America (Rankin and 

others, 1989; Thomas, 1991). A Middle Cambrian rifting event, more moderate in scale than the Neoproterozoic rifting event, formed the Rome trough about 200 

mi inland from the evolving passive margin (Beardsley 

and Cable, 1983; Read, 1989a,b; Shumaker, 1996).

In contrast, the major thin-skinned structures are 

contractional in origin and probably developed during 

the Late Mississippian to Permian continental collision 

(Alleghanian orogeny) between eastern North America and Africa (Rodgers, 1988; Hatcher and others, 

1989). The crustal contraction that accompanied the 

Late Mississippian to Permian collision caused large 

horizontal displacements of thick, competent panels 

of Paleozoic strata along thin, incompetent Paleozoic 

strata. In places, the Alleghanian orogeny reactivated 

basement faults and locally inverted the Rome trough 

(Harris, 1978; Shumaker and Wilson, 1996; Scanlin and 

Engelder, 2003; Kulander and Ryder, 2005). Typical 

Appalachian thin-skinned structures are bedding-plane 

detachment zones, footwall ramps, ramp anticlines, and 

imbricate thrust faults (Rodgers, 1963; Gwinn, 1964, 

1970; Wilson and Shumaker, 1985; Woodward, 1985; 

Kulander and Dean, 1986; Faill and Nickelsen, 1999).

Basement Rocks and Associated 

Structures

The basement rocks along cross section C–C′

consist largely of igneous and metamorphic rocks of the 

subsurface extension of the Grenville province (Rankin 

and others, 1993). Most isotopic ages of these rocks 

range between 950 and 1,350 million years old (megaannum, or Ma), and many ages cluster around 1,000 to 

1,100 Ma (Rankin and others, 1993) (fig. 2). Lidiak and 
6 Geologic Cross Section C–C’ Through the Appalachian Basin

others (1966) reported a potassium-argon (K-Ar) age 

of 935 Ma for gneiss and schist in the No. 1 Bruns drill 

hole (Sandusky County, Ohio), which is located about 

50 mi west of drill hole 1, and in the No. 1 Arting drill 

hole (Huron County, Ohio), which is located about 20 

mi southeast of drill hole 1 (fig. 1). As shown on nearby 

geologic cross section E–E′ (Ryder and others, 2008) 

(fig. 1), Lidiak and others (1966) reported a rubidiumstrontium (Rb-Sr) age of 860 Ma for biotite granite in 

drill hole 5 and a K-Ar age of 850 Ma for granodiorite 

gneiss in drill hole 11. Although the ages reported by 

Lidiak and others (1966) are younger than the 950 Ma 

upper limit of Mesoproterozoic basement rocks suggested by Rankin and others (1993), rocks with these 

ages are grouped in this report with rocks of the Grenville province on the basis of their similar lithology and 

structural style. The basement rock in drill hole 1 of this 

cross section is described as a medium-grained granite 

that contains predominantly orthoclase, quartz, and 

accessory biotite and plagioclase (McCormick, 1961). 

Moreover, the basement rocks in drill holes 12, 13, and 

14 in nearby cross section E–E′ are described, respectively, as granite gneiss, gneiss and granite, and quartzoligoclase-biotite gneiss that contains graphite and 

sillimanite (King and others, 1998). Van Schmus and 

others (1996) reported a samarium-neodymium (SmNd) age of 1,272 Ma for gabbro basement in drill hole 4 

on cross section E–E′ (see Wickstrom and others, 1985; 

Ryder and others, 2008) (fig. 1) but could not explain 

the absence of Mesoproterozoic penetrative deformation 

and associated resetting of the apparent age.

The western margin of the subsurface extension 

of the Grenville province is marked by the Grenville 

front (fig. 1), along which intensely deformed Mesoproterozoic metamorphic and igneous rocks (commonly 

characterized by west-verging thrust faults; Culotta and 

others, 1990) are juxtaposed against mildly deformed 

1,470 Ma rocks of the eastern granite-rhyolite province to the west (Van Schmus and others, 1996). The 

basement-involved Bowling Green fault zone, located 

about 70 mi west of the northwestern end of the cross 

section, forms the approximate boundary between 

the Mesoproterozoic basement rocks and rocks of the 

granite-rhyolite province (fig. 1; Wickstrom and others, 

1992; Baranoski, 2002). The Coshocton zone, a 50- to 

100-mi-wide zone of east-verging penetrative deformation in the Mesoproterozoic basement, is located 

approximately between 5 mi east of well 4 and 8 mi 

east of well 7 in the eastern Ohio and westernmost 

Pennsylvania part of cross section C–C′. This zone 

was identified by Culotta and others (1990) from deep 

seismic reflections on COCORP profiles and was interpreted by them to mark the site of a suture zone within 

the Grenville province.

The basement of the Appalachians is a homoclinal ramp that dips gently from an interior craton to the 

external margin of a fold-and-thrust belt, which is typical of many foreland basins. Along cross section C–C′, 

this basement ramp deepens progressively southeastward from about 3,600 ft below mean sea level (MSL) 

at drill holes 1 and 2 to about 25,000 ft below MSL 

beneath the Allegheny structural front at drill hole 10. 

This gradual eastward deepening of the basement ramp 

along section C–C′ is interrupted by the Rome trough 

(fig. 1), a Middle Cambrian rift system that drops the 

basement rocks to as much as 28,000 ft below MSL. 

The western limit of the Rome trough is defined here as 

the down-to-the-east normal fault located about 35 mi 

east of drill hole 7 (Shumaker, 1996; Baranoski, 2002), 

and the eastern limit of the Rome trough is defined as 

the down-to-the-west normal fault several miles east 

of drill hole 9 (Shumaker, 1996; Kulander and Ryder, 

2005). Our interpretation of the boundary faults of the 

Rome trough differs from that of Scanlin and Engelder 

(2003), who place the western boundary fault near the 

Belle Vernon anticline (about 23 mi west of drill hole 

8) and the eastern boundary fault near the Chestnut 

Ridge anticline (beneath drill hole 8). Along cross section C–C′, the Rome trough is about 40 to 45 mi wide 

and has a structural relief on basement that ranges from 

several hundred feet at its western margin to an estimated 8,000 ft at its eastern margin. Although many of 

the basement faults of the Rome trough shown in cross 

section C–C′ have been recognized in previous studies 

(Wagner, 1976; Shumaker, 1996; Scanlin and Engelder, 

2003; Kulander and Ryder, 2005), the overall structural 

interpretation presented here for the deep lower Paleozoic section in section C–C′ is speculative because 

deep-drill-hole data are absent. The northern extension 

of the Central West Virginia arch, a large northeasttrending basement block identified by Kulander and 

Dean (1986), flanks the eastern margin of the Rome 

trough in south-central Pennsylvania and dips gently 

eastward beneath the Allegheny structural front and the 

western part of the Valley and Ridge province.

In northeastern Ohio, the basement ramp locally 

is modified by a northwest-trending zone of en echelon 

faults that is subparallel to cross section C–C′ (fig. 1). 

From northwest to southeast, these faults have the following names: Middleburg fault, Akron fault, Suffield 

fault system, Smith Township fault, and Highlandtown 

fault (Baranoski, 2002) (fig. 1). Based on interpretations by Gray (1982a,b) and Baranoski (2002), the 

basement along cross section C–C′ shows a vertical 

separation of about 50 ft across the Middleburg fault 

(near drill hole 3) and about 100 ft across the Suffield 

fault system (about 9 mi west of drill hole 4). Additional evidence for basement offset along the Suffield 

fault system is presented by Root and Onasch (1999) 

and is based on seismic records.

The northwest-trending fault zone in northeastern 

Ohio continues into Pennsylvania as the northwesttrending Pittsburgh-Washington cross-strike structural 

discontinuity (Lavin and others, 1982; Parrish and 

Lavin, 1982) (fig. 1). This structural discontinuity is 

inferred to be a deeply rooted basement fault zone 

along which strike-slip to dip-slip offset has occurred 

(Lavin and others, 1982; Harper, 1989). The PittsburghWashington cross-strike structural discontinuity crosses 

section C–C′ line in three places: (1) between drill 

holes 6 and 7, (2) about midway between drill holes 7 

and 8, and (3) about 5 mi west of drill hole 9 (fig. 1). 

Seismic records interpreted by Scanlin (2000) support 
Structural Framework 7

the presence and the probable recurrent nature of this 

ancient fault zone in basement rocks beneath the Laurel 

Hill anticline.

Other structures that involve basement rocks 

include various inflections in the basement ramp. Minor 

inflection points or hinge zones in the basement ramp 

occur between drill holes 2 and 3, between drill holes 

3 and 4, and at drill hole 5 in north-central Ohio. The 

north-central Ohio inflection point between drill holes 

2 and 3 may represent the northern extension of the 

Cambridge arch (Cambridge cross-strike structural 

discontinuity of Baranoski, 2002) (fig. 1), which is a 

north-trending basement arch identified by Root (1996) 

from seismic data and from isopach patterns in selected 

Paleozoic strata. Furthermore, the hinge zone between 

drill holes 3 and 4 probably represents offset along 

the Suffield fault, whereas the hinge zone at drill hole 

5 probably represents a simple flexure. Also, a major 

33-mi-wide hinge zone extends from drill hole 7 near 

the West Virginia-Pennsylvania border to about midway 

between drill holes 7 and 8 and approximately coincides with the Ohio-West Virginia hinge zone of Ryder 

and others (1992) that marks the western margin of the 

Rome trough (fig. 1). This wide hinge zone was caused 

by multiple down-to-the-east normal faults.

Most normal (extensional) faults associated with 

the Rome trough rift system were reactivated several 

times during the Paleozoic to produce either renewed 

subsidence or small-scale basin inversion (Shumaker 

and Wilson, 1996). For example, small-scale basin 

inversion has been documented along segments of the 

Rome trough in northern West Virginia and southwestern Pennsylvania where basement-involved normal 

(extensional) faults were reactivated as reverse (contractional) faults to create mildly inverted grabens 

(Scanlin and Engelder, 2003; Kulander and Ryder, 

2005). Most of the small-scale inversion probably 

resulted from contraction during the Late Mississippian 

to Permian Alleghanian orogeny.

The Laurel Hill anticline, which crests near well 

9 on cross section C–C′ (figs. 1, 3), is interpreted in 

this study to be an example of the basin inversion during the Alleghanian orogeny that controlled the initial 

phases of anticlinal growth. The structural geometries 

shown by seismic lines that cross the anticline indicate 

that the Laurel Hill anticline is deeply rooted in lower 

Paleozoic strata and Mesoproterozoic basement rocks 

(Scanlin and Engelder, 2003). The movement that produced this anticline probably was caused by a reversal 

in motion during Alleghanian deformation of the preexisting, down-to-the-west normal fault that serves as 

the eastern boundary of the Rome trough. Furthermore, 

the deep-seated Laurel Hill anticline was modified by 

west-verging faults (footwall ramps) that offset the 

crest of the anticline at about 15,700 and 18,600 ft in 

drill hole 9 and are connected with a detachment zone 

(hangingwall flat) in the Ordovician Antes Shale (fig. 

3). These small, west-verging footwall ramps originated 

where the basal zone of detachment in the Cambrian 

Waynesboro Formation was juxtaposed against more 

competent carbonate beds of the Cambrian Warrior Formation. As shown on cross section C–C′ and by Scanlin 

and Engelder (2003), the upper third of the Laurel Hill 

anticline is detached along the Silurian Salina Group 

and the Middle Devonian Marcellus Formation and 

shows characteristics that are clearly of thin-skinned 

origin. We suggest that this initial deep-seated relief 

on the Laurel Hill anticline interrupted the westwardpropagating Salina and Marcellus detachments (footwall flats) (fig. 3) to form thin-skinned structures 

in the upper third of the anticline. In contrast to our 

interpretation that involves basin inversion, Scanlin and 

Engelder (2003) interpreted the deep-seated part of the 

Laurel Hill anticline to be an east-facing coastal declivity created by several down-to-the-east basement faults. 

In either case, deep structural relief is called upon to 

interrupt zones of bedding-plane detachment to form 

upper-level, thin-skinned structures in the anticline.

The Chestnut Ridge anticline (located at drill 

hole 8) may be another example on cross section 

C–C′ where both basement and thin-skinned tectonics 

probably have contributed to the origin of first-order 

anticlines in the Appalachian Plateau province. The 

influence of basement tectonics on the evolution of the 

Chestnut Ridge anticline is shown by the deeply rooted 

character of the anticline (Scanlin and Engelder, 2003), 

whereas the influence of thin-skinned tectonics on the 

anticline is shown by bedding-plane detachment and 

disharmonic folding in the Silurian Salina Group (Shumaker, 2002; Scanlin and Engelder, 2003). We propose 

the following two-stage origin for the Chestnut Ridge 

anticline: (1) the deeply rooted part of the Chestnut 

Ridge anticline is the result of reverse-motion reactivation (during the Alleghanian orogeny) along a Rome 

trough basement fault zone that originally had a downto-the-west normal sense of separation; and (2) the 

locations of the thin-skinned structures in the Chestnut 

Ridge anticline are controlled by deep-seated structural 

relief, which interrupted westward-propagating zones 

of bedding-plane detachment in the Salina Group, and 

possibly in the Marcellus Formation and Antes Shale. 

Scanlin and Engelder (2003) also favor a two-stage 

origin for the Chestnut Ridge anticline, but suggested 

that the deep-seated structural relief associated with 

the anticline was caused by an upthrown basement 

fault block at the eastern margin of the Rome trough 

(as defined by Scanlin and Engelder, 2003) rather than 

by an upthrown basement fault block within the Rome 

trough.

Other anticlines on cross section C–C′ that may 

have originated by reverse-motion reactivation along 

basement-involved normal faults in the Rome trough 

are the Fayette, Brownsville, Belle Vernon, and Amity 

anticlines (fig. 1). Although Scanlin (2000) and Scanlin 

and Engelder (2003) have interpreted basement faults 

beneath all of these anticlines, they have not documented recurrent fault movement.

Thin-Skinned Structures

Thin-skinned structures in the Valley and Ridge 

province part of cross section C–C′ include the Wills 
8 Geologic Cross Section C–C’ Through the Appalachian Basin

Mountain anticline and the Evitts Mountain anticline 

(Gwinn, 1970; de Witt, 1974; Shumaker and Wilson, 

1985; Faill, 1998). These prominent anticlines have 

high amplitudes and are westward verging. Major thinskinned structures in the eastern part of the Appalachian 

Plateau province in cross section C–C′ include the 

Schellsburg dome at the northeastern end of the Deer 

Park anticline, the Negro Mountain anticline, the Laurel 

Hill anticline, and the Chestnut Ridge anticline (Gwinn, 

1964, 1970; Rodgers, 1970; Scanlin and Engelder, 

2003). These thin-skinned anticlines in the eastern part 

of the Appalachian Plateau province have moderate 

to high amplitudes, and several have complex triangle 

zones accompanied by east- and west-verging imbricate 

faults (Shumaker and Wilson, 1985; Shumaker, 2002; 

Scanlin and Engelder, 2003). All thin-skinned anticlines 

shown on cross section C–C′ originated during the Late 

Mississippian to Permian Alleghanian orogeny (Rodgers, 1970; Faill, 1998; Faill and Nickelsen, 1999).

The Schellsburg dome at the northern end of the 

Deer Park anticline, the Wills Mountain anticline, and 

the Evitts Mountain anticline constitute a group of 

three west-verging, allochthonous blocks of Cambrian 

and Ordovician carbonate rocks that are separated by 

major footwall ramps (thrust faults) that have branched 

off a basal detachment in the Cambrian Waynesboro 

Formation (Gwinn, 1970; Berg and others, 1980) (fig. 

3). These allochthonous blocks, which represent about 

14 to 15 mi of lateral shortening, are juxtaposed against 

a subhorizontal parautochthonous block of Cambrian, 

Ordovician, and Silurian rocks (fig. 3).

The master footwall ramp or thrust fault of 

the Schellsburg dome (which makes up the western 

allochthonous block shown on figure 3) is estimated 

to be about 16,500 ft below MSL on the eastern limb 

of the dome, where allochthonous siliciclastic rocks of 

the Cambrian Waynesboro Formation are juxtaposed 

against parautochthonous carbonate rocks of the Lower 

and Middle Ordovician Beekmantown Group and 

Upper Cambrian Gatesburg Formation. As shown by 

Gwinn (1970), and previously discussed in this report, 

the master footwall ramp of the Schellsburg dome 

flattens into a hangingwall flat in the Antes Shale (fig. 

3). Moreover, zones of bedding-plane detachment may 

form roof thrusts in the Ordovician Antes Shale (about 

7,400 ft depth in drill hole 10) and the Silurian Tonoloway and Wills Creek Formations (about 1,000 ft depth 

in drill hole 10). The proposed roof thrust in the Antes 

Shale merges with the hangingwall flat beneath the 

western limb of the dome, whereas the roof thrust in the 

Tonoloway and Wills Creek Formations continues west 

of the dome as a major detachment zone in the Silurian 

Salina Group. Furthermore, a bedding-plane roof thrust 

probably also exists in the Middle Devonian Marcellus Formation at the Schellsburg dome based on the 

regional Middle Devonian shale detachment proposed 

by Evans (1994). Additional structural complications 

in the Schellsburg dome, shown on section C–C′, are 

back-limb thrust faults that branch off the major basal 

detachment in the Waynesboro Formation. One of these 

back-limb thrust faults offsets the bedding plane (roof 

thrust) in the Antes Shale near the crest of the dome 

(fig. 3) and offsets the Silurian Rose Hill Formation in 

the core of the dome at about 1,000 ft below MSL in 

drill hole 10. Other back-limb thrust faults are located 

about 2 to 7 mi east of the crest of the Schellsburg 

dome (fig. 3).

The master footwall ramp or thrust fault of the 

Wills Mountain anticline (which makes up the middle 

allochthonous block shown on figure 3) branches 

off the basal detachment and propagates upsection 

at least as far as the Upper Devonian Scherr Formation. Although undrilled along cross section C–C′, the 

master thrust of the Wills Mountain anticline (fig. 3) is 

estimated to be about 5,500 ft beneath the exposed crest 

of the anticline and involves carbonate rocks of the 

Ordovician Beekmantown Group juxtaposed against 

siliciclastic rocks of the younger Ordovician Bald Eagle 

and Juniata Formations. In the Kerr-McGee No. 1 

Martin drill hole (fig. 1), about 9 mi southwest of cross 

section C–C′, the master thrust of the Wills Mountain 

anticline places the Ordovician Beekmantown Group 

over the younger Ordovician Reedsville Shale at a 

depth of 6,200 ft (Knowles, 1966). West of the Wills 

Mountain anticline, the master thrust in the No. 1 Martin drill hole flattens into a bedding-plane fault (hangingwall flat) in the Reedsville Shale (Knowles, 1966) 

and then probably rises over the crest of the Deer Park 

anticline as a roof thrust. The Wills Mountain anticline 

in the vicinity of cross section C–C′ is cut by several 

back-limb thrust faults that branch off the basal detachment. The largest of these back-limb thrusts, as shown 

on cross section C–C′ and by Berg and others (1980), 

cuts through Cambrian and Ordovician carbonate 

rocks as far upsection as the Reedsville Shale, where 

it flattens into a bedding-plane fault at the crest of the 

anticline (fig. 3). Furthermore, this bedding-plane thrust 

may act as a roof thrust that joins the master footwall 

ramp of the Wills Mountain anticline. Also, a secondary imbricate thrust (shown on cross section C–C′ and 

by Berg and others, 1980) branches off the primary 

back-limb thrust fault in the Ordovician Beekmantown 

Group and ends about 9,000 ft farther upsection in the 

Ordovician Juniata Formation (fig. 3).

The master footwall ramp or thrust fault of the 

Evitts Mountain anticline (which makes up the eastern 

allochthonous block shown on figure 3) is located at 

about 6,800 ft depth in drill hole 11, where a highly 

deformed complex of thin, repeated thrust slices (horse 

blocks) of the Cambrian Waynesboro and Pleasant 

Hill Formations are juxtaposed against the Ordovician 

Beekmantown Group. A net structural relief of 3.5 to 4 

mi is caused by the duplicated Waynesboro Formation 

in the anticline. An additional structure, a frontal imbricate thrust (fig. 3), branches off the master thrust fault 

of the Evitts Mountain anticline and places the Upper 

Cambrian Gatesburg Formation against the Beekmantown Group at about 12,600 ft depth in drill hole 11. 

This frontal imbricate thrust also places the Ordovician Black River Group against the younger Reedsville 

Shale at the surface west of drill hole 11.

From its juncture with the master thrust of 

the Schellsburg dome, the basal detachment in the 
Stratigraphic Framework 9

Cambrian Waynesboro Formation continues farther 

west for about 40 mi beneath the parautochthonous 

block (Berg and others, 1980) to the eastern margin 

of the Rome trough (fig. 3). West-verging thrust faults 

branch upward from this basal detachment and subdivide the parautochthonous block into several minor 

thrust blocks. The westernmost of the minor thrust 

faults is located beneath the Laurel Hill anticline, 

where the basal detachment abuts Cambrian carbonate 

rocks and ramps upsection to join a higher detachment (hangingwall flat) in the Ordovician Antes Shale. 

Another interpreted minor thrust fault is located in the 

parautochthonous block beneath the Negro Mountain 

anticline, where it may have influenced folds and thrust 

faults associated with the Salina and Marcellus detachment zones.

The major detachment zone (hangingwall flat) 

in the Salina Group west of the Schellsburg dome is 

interpreted on section C–C′ to continue westward for 

another 115 to 145 mi, where the detachment zone 

underlies complex thin-skinned structures such as 

triangle zones, imbricate thrusts, and disharmonic folding in the cores of the Negro Mountain, Laurel Hill, 

and Chestnut Ridge anticlines (Scanlin and Engelder, 

2003). As previously noted, complex thin-skinned 

deformation in the cores of the Laurel Hill and Chestnut Ridge anticlines is probably related in part to 

pre-existing or penecontemporaneous zones of positive, 

northeast-trending structural relief caused by reactivated basement faults. Although the Negro Mountain anticline probably also is related to deep-seated 

structural relief, the relief very likely was caused by an 

imbricate fault that branched off the basal detachment 

rather than by a reactivated basement-involved fault.

As shown on cross section C–C′, the Salina 

detachment in the Negro Mountain, Laurel Hill, and 

Chestnut Ridge anticlines is interpreted according to 

the three-tiered model for plateau anticlines proposed 

by Scanlin and Engelder (2003, adapted from Gwinn, 

1964). This model consists of a detachment zone at the 

base of the anticline, a middle imbricate zone, and an 

upper wedge zone. Scanlin and Engelder (2003) proposed that the zone of regional detachment is located 

in shale and evaporite beds near the base of the Salina 

Group instead of being located in halite- and anhydritebearing beds in the middle part of the Salina Group, as 

favored by Gwinn (1964). Because the shale-bearing 

part of the Salina Group is not identified in this study, 

the regional detachment is placed by default in the 

halite-bearing middle part of the Salina Group. Furthermore, the interpretation by Gwinn (1964) of the structure of the Chestnut Ridge anticline has been revised 

by Shumaker (2002) using new well-log, dipmeter, and 

seismic data. According to this revised interpretation 

(and as shown on cross section C–C′), the structurally 

low and relatively undeformed axial zone (or triangle 

zone) interpreted by Gwinn (1964) is replaced by a 

highly faulted, deep syncline located between the central and western structural highs of the Chestnut Ridge 

anticline.

Bedding-plane detachment in the Marcellus Formation (interpreted to be present at Schellsburg dome) 

also is interpreted to be present at the Negro Mountain, 

Laurel Hill, and Chestnut Ridge anticlines. For example, an interpretation by Shumaker (2002) placed a 

detachment in the Marcellus Formation at the Chestnut 

Ridge anticline, and an interpretation by Evans (1994) 

placed a regional detachment in the Marcellus Formation extending from the Allegheny structural front to 

at least westernmost Pennsylvania. Following these 

interpretations, small imbricate thrust faults are shown 

on cross section C–C′ that branch off the Marcellus 

Formation detachment zone at Negro Mountain, Laurel 

Hill, and Chestnut Ridge anticlines and further contribute to the structural complexity of these anticlines.

The small, northeast-trending Fayette, Brownsville, Belle Vernon, and Amity anticlines, which are 

located west of the Chestnut Ridge anticline, probably 

were caused by minor thrust faults that branch upward 

from the Salina detachment zone. Although not shown 

on the cross section, several of the minor thrust faults 

beneath the small anticlines may branch upward from 

the Marcellus detachment zone. Moreover, these partially detached anticlines are interpreted here to have 

been controlled by deeply rooted structural relief associated with reactivated basement faults. The Salina and 

Marcellus detachments probably continue westward 

from the Amity anticline, possibly as far west as eastern 

Ohio (Evans, 1994; Faill, 1998).

Stratigraphic Framework

The sedimentary rocks shown on cross section 

C–C′ span most of the Paleozoic Era, and their thickness 

ranges from about 4,600 ft at drill holes 1 and 2 to nearly 

27,000 ft at the Allegheny structural front at drill hole 10. 

Lithology, nomenclature, and depositional and tectonic 

settings of the sedimentary rocks along cross section 

C–C′ are briefly outlined and discussed in the following 

text. A more detailed treatment is available in regional 

geological summaries by Colton (1970), Milici and de 

Witt (1988), Read (1989a,b), and Faill (1997a,b, 1998).

Much of the eastward thickening of strata in the 

Appalachian basin was caused by regional tectonism. 

During the Neoproterozoic to Early Cambrian, as the 

proto-Atlantic (Iapetus) Ocean opened and formed a 

rifted continental margin, cooling and thermal contraction of the lithosphere caused subsidence, which 

provided accommodation or preservation space for 

sediments to build an eastward-facing passive continental margin (Bond and others, 1988; Read, 1989a). During several later periods in the Paleozoic, subsidence 

caused by thrust loading provided additional accommodation or preservation space for sediments to accumulate in Appalachian foreland basins (Quinlan and Beaumont, 1984). Eustatic changes also have played a role 

in the eastward thickening of Appalachian strata (Bond 

and others, 1988). For example, a rise in sea level can 

cause load-induced subsidence (by sediments and the 

overlying water column) and provide accommodation 

space for additional sediments on the outer continental 

shelf, whereas a fall in sea level can cause erosion of 
10 Geologic Cross Section C–C’ Through the Appalachian Basin

the inner continental shelf. These eustatic changes were 

caused by changes in global climate and (or) changes in 

regional tectonic activity.

Lower Cambrian to Upper Ordovician 

Siliciclastic and Carbonate Strata

Lower Cambrian to Upper Ordovician siliciclastic and carbonate strata are characterized by dolomite, 

anhydritic dolomite, limestone, and lesser amounts 

of gray shale, red shale, and sandstone (fig. 2). These 

strata thin dramatically from about 6,700 ft in the 

western part of the Rome trough in south-central 

Pennsylvania to about 1,300 ft in north-central Ohio. 

In the eastern part of the Rome trough in south-central 

Pennsylvania, Lower Cambrian to Upper Ordovician 

strata are estimated to thicken to as much as 15,000 ft, 

of which about 6,000 ft are penetrated in drill hole 9. In 

the eastern part of cross section C–C′ (Rome trough to 

the Valley and Ridge province), the Lower Cambrian 

to Upper Ordovician siliciclastic and carbonate strata 

consist of the following units (in ascending order): the 

Chilhowee Group, Tomstown Formation, Waynesboro 

Formation, Pleasant Hill Formation, Warrior Formation, 

Gatesburg Formation, Beekmantown Group, Loysburg 

Formation, Black River Group, and Trenton Group 

(fig. 2). The nomenclature of the Chilhowee Group, 

Tomstown Formation, and Waynesboro Formation in 

this cross section follows that of Fauth (1968) and Root 

(1968) in south-central Pennsylvania, Kulander and 

Dean (1986) in northernmost West Virginia, Southworth and others (2009) in northern Virginia, and Brezinski (1992) in Maryland. The equivalent Cambrian to 

Upper Ordovician strata in the western part of the cross 

section consist of the following units (in ascending 

order): Mount Simon Sandstone, Conasauga Group, 

Kerbel Formation, Knox Dolomite (which includes 

the informally used Copper Ridge dolomite, Rose Run 

sandstone, and Beekmantown dolomite), Wells Creek 

formation (informal usage), Black River Group, and 

Trenton Limestone (fig. 2). The Rome Formation of 

Janssens (1973) is now considered to be an obsolete 

stratigraphic term in eastern and central Ohio (Harris 

and others, 2004; Baranoski and others, 2007) and is 

not used in cross section C–C′.

The distribution and lithology of Cambrian rocks 

in the eastern part of cross section C–C′ are very 

speculative because deep drill holes are largely absent. 

Lithology and thickness data for Cambrian rocks in this 

area are limited to (1) drill hole 9, where the upper part 

of the Gatesburg Formation is penetrated; (2) drill hole 

11, where the upper part of the Waynesboro Formation 

through the Gatesburg Formation is penetrated; and (3) 

outcrop studies in the vicinity of drill hole 11 (Wilson, 

1952). Supplementary data for these Cambrian rocks 

were obtained from drill holes 9 and 13 on nearby cross 

section D–D′ and from drill holes 11 through 14 on 

cross section E–E′ (fig. 1). Drill hole 9 (cross section 

D–D′) near the western margin of the Rome trough 

penetrated the uppermost Copper Ridge Dolomite and 

the Rose Run Sandstone (together equivalent stratigraphically to the Gatesburg Formation in cross section 

C–C′), whereas drill hole 13 (cross section D–D′) in the 

Valley and Ridge province penetrated the upper part 

of the Waynesboro Formation, the Elbrook Formation 

(equivalent stratigraphically to the Pleasant Hill and 

Warrior Formations on cross section C–C′), and the 

Copper Ridge Dolomite (equivalent stratigraphically 

to the Gatesburg Formation on cross section C–C′). By 

comparison, drill holes 11 through 14 in cross section 

E–E′ (located 100 to 130 mi southwest of section C–C′) 

penetrated the entire Cambrian section in the Rome 

trough. Cambrian units between the western margin of 

the Rome trough and the western end of cross section 

C–C′ are reasonably well documented by drill holes 1 

through 5.

On cross section C–C′, the Lower Cambrian Chilhowee Group, the Lower Cambrian Tomstown Formation, and the Lower and Middle Cambrian Waynesboro 

Formation are estimated to have a combined thickness of as much as 3,500 ft in the Rome trough and 

between 1,400 and 2,300 ft on the northern extension 

of the Central West Virginia arch and in the Valley and 

Ridge province. The 50- to 250-ft-thick basal sandstone between the western margin of the Rome trough 

and drill hole 1 is recognized as the Middle and Upper 

Cambrian Mount Simon Sandstone in Ohio and the 

Potsdam Formation in Pennsylvania.

The Lower Cambrian Chilhowee Group (a basal 

sandstone that rests unconformably on Mesoproterozoic basement rocks of the Grenville province) and 

the overlying Lower Cambrian Tomstown Formation 

are the two oldest sedimentary units on cross section 

C–C′. Although neither unit has been penetrated by a 

drill hole in cross section C–C′, a combined thickness 

of about 500 to 800 ft is estimated from outcrops and 

regional trends. Following Root (1968), the Chilhowee through Tomstown interval is interpreted here 

to continue east of cross section C–C′ and crop out in 

south-central Pennsylvania along the Blue Ridge structural front (fig. 1). Westward, the Chilhowee through 

Tomstown interval is interpreted on cross section C–C′

to pinch out across basement fault blocks near the center of the Rome trough.

The Chilhowee Group is interpreted as a transgressive marine deposit with its sediment source to the 

west. The overlying carbonate strata of the Tomstown 

Formation also are interpreted as transgressive marine 

deposits that accumulated on a marine shelf and carbonate ramp after the adjacent craton was submerged 

by the Iapetus Ocean (Read, 1989a,b).

The Chilhowee through Tomstown interval possibly is capped by a disconformity (fig. 2), which is 

overlain by the Waynesboro Formation (Ryder and 

others, 1992). The age of the Waynesboro Formation is uncertain. Although an Early Cambrian age 

is commonly cited for the Waynesboro Formation 

(Butts, 1945; Palmer, 1971; Kulander and Dean, 1986; 

Brezinski, 1992), fossil evidence is very sparse and 

a Middle Cambrian age is plausible for part of the 

formation (Stose, 1909; Woodward, 1949; Root, 1968; 

Read, 1989a,b). An Early and Middle Cambrian age is 
Stratigraphic Framework 11

assigned to the Waynesboro Formation in this report, 

based on probable Middle Cambrian fossils in the 

Rome Formation (equivalent to the Waynesboro Formation) in the Rome trough of western West Virginia 

(Donaldson and others, 1988). Beneath drill hole 9 in 

the Rome trough, we speculate that the Waynesboro 

Formation consists of approximately 2,600 ft of gray 

shale with local beds of red shale, sandstone, and 

dolomite.

At 5,620 ft depth in drill hole 11, the upper 120 

ft of the Waynesboro Formation are characterized by 

red and green shale, dolomite, and sandstone. At this 

locality, the strata of the Waynesboro Formation rest in 

fault contact on the Cambrian Pleasant Hill Formation. 

The Pleasant Hill and Waynsboro have been repeated 

by thrust faults into three horse blocks. The Waynesboro Formation and the underlying horse blocks of the 

Pleasant Hill Formation probably were derived from 

the basal detachment and the master thrust or footwall 

ramp of the Evitts Mountain anticline, tectonically 

transported westward along the footwall ramp (with a 

net vertical displacement of as much as 20,000 ft), and 

juxtaposed against the Beekmantown Group. Along 

the basal detachment between drill holes 9 and 11, the 

Waynesboro Formation consists of a westward-tapering 

wedge (as much as 1,500 ft thick) of clastic red beds 

and carbonate strata that overlie the Tomstown Formation and pinch out near the crest of the northern extension of the Central West Virginia arch. The lithology 

of the Waynesboro Formation at this locality probably 

consists of red, green, and gray shale, sandstone, and 

dolomite, based on the lithology of the Waynesboro 

Formation in drill hole 11 and in outcrop studies by 

Root (1968) in south-central Pennsylvania, by Woodward (1949) in eastern West Virginia, Southworth 

and others (2009) in northern Virginia, and Brezinski 

(1992) in Maryland.

On the basis of cross sections D–D′ and E–E′ (see 

fig. 1 for locations), the Waynesboro Formation probably changes in lithology from gray, shale-dominated 

strata with local beds of sandstone and carbonate rock 

in the central part of the Rome trough to argillaceous 

sandstone with local beds of red shale and dolomite 

in the western part of the Rome trough. The argillaceous sandstone of the Waynesboro Formation in the 

western part of the Rome trough rests directly either 

on Mesoproterozoic basement rocks of the Grenville 

province or on a thin section of the Chilhowee Group, 

thins progressively westward across successive fault 

blocks in the Rome trough, and terminates against a 

fault beneath the No. 1 McMichael drill hole. The argillaceous sandstone of the Waynesboro Formation very 

likely intertongues with gray shale of the Waynesboro 

and carbonate rocks of the Pleasant Hill Formation and 

the lower part of the Warrior Formation in the vicinity 

of the Brownsville anticline. West of the Rome trough, 

the Waynesboro Formation is replaced by the Middle 

and Upper Cambrian Potsdam Formation in Pennsylvania and equivalent Mount Simon Sandstone in Ohio, 

both of which are younger than the Waynesboro (see 

the western margin of the Rome trough on cross section 

C–C′ and drill holes 1, 2, 3, and 5).

In outcrops in eastern West Virginia and in 

the subsurface of the Rome trough in western West 

Virginia, the Waynesboro Formation is interpreted as 

a shallow-water, nearshore-marine deposit (Woodward, 1949; Donaldson and others, 1988). The marked 

contrasts that exist between the thin, clastic, red bedand carbonate-dominated Waynesboro Formation of 

the northern extension of the Central West Virginia 

arch and the thick, gray, shale-dominated Waynesboro 

Formation of the Rome trough probably indicate a 

change from continental-shelf to rift-basin sedimentation. The Waynesboro strata shown on cross section 

C–C′ probably began as shallow-marine-shelf deposits 

that accumulated on a uniformly subsiding continental 

margin and then shifted rather abruptly to more locally 

derived shallow-marine deposits that accumulated in 

the separate rift basins with adjoining high basement 

blocks that constitute the Rome trough. The Mount 

Simon Sandstone and Potsdam Formation are interpreted as transgressive deposits.

The Pleasant Hill Formation is interpreted to rest 

conformably on the Waynesboro Formation, except 

along the crest of the northern extension of the Central 

West Virginia arch. A complete section of the Middle 

Cambrian Pleasant Hill Formation is penetrated in drill 

hole 11 at the eastern end of cross section C–C′, where 

the Pleasant Hill Formation is about 400 to 500 ft thick 

(this thickness is probably apparent because of dipping 

strata) and consists of a limestone that becomes more 

argillaceous in the lower 100 ft. Previously mentioned 

horse blocks of the Pleasant Hill Formation underlie 

this complete section in drill hole 11. These horse 

blocks range in thickness from 490 to 630 ft and consist 

of similar limestone and argillaceous limestone units. 

West of drill hole 11, the Pleasant Hill Formation is 

interpreted to be present throughout the Valley and 

Ridge province and the northern extension of the Central West Virginia arch, and it extends about 35 mi into 

the Rome trough. The combined thickness of the Pleasant Hill Formation through Trenton Group is 8,500 ft 

near the Allegheny structural front (based on the section near drill hole 10) and about 9,000 ft in the middle 

of the Rome trough, under the Lambert syncline. In the 

eastern part of the Rome trough, this interval may be as 

thick as 11,000 ft.

The Pleasant Hill Formation in drill hole 11 is 

conformably overlain by the Middle and Upper Cambrian Warrior Formation, which is 1,400 ft thick and 

consists primarily of sandy dolomite with a 380-ft-thick 

upper limestone unit. The sandy dolomite of the Warrior 

Formation in Pennsylvania (and the equivalent Conasauga Group in Ohio and northernmost West Virginia) 

stretches across all of cross section C–C′; however, the 

limestone unit at the top of the Warrior Formation in 

drill hole 11 only extends to within 9 mi of the crest 

of the northern extension of the Central West Virginia 

arch, where the Warrior Formation is truncated by an 

unconformity. In the region between drill hole 11 and 

the eastern margin of the Rome trough, the contact 

between the Warrior and Pleasant Hill Formations 

remains conformable except near the crest of the arch. 
12 Geologic Cross Section C–C’ Through the Appalachian Basin

Moreover, the Warrior Formation is estimated to thicken 

abruptly from about 200 ft on the crest of the arch, 

where repeated episodes of uplift have occurred, to as 

much as 3,600 ft in the adjoining eastern part of the 

Rome trough. In addition to the thickening, a dolomitic 

sandstone unit is interpreted to be present at the base 

of the Warrior Formation on the basis of the presence 

of a 450-ft-thick unnamed sandstone unit in the middle 

part of the Maryville Limestone in cross section E–E′

(drill holes 13 and 14). This basal sandstone unit of the 

Warrior Formation conformably overlies the Pleasant 

Hill Formation in the Rome trough as far west as the 

Brownsville anticline (middle part of the Rome trough), 

where the Pleasant Hill pinches out into the Waynesboro Formation. Westward from the pinch out edges 

of the Pleasant Hill Formation and the basal sandstone 

of the Warrior Formation to about as far as the western 

margin of the Rome trough, the main dolomite body 

of the Warrior Formation conformably overlies the 

Waynesboro Formation. As interpreted here, the lower 

part of the Warrior Formation locally intertongues with 

the upper part of the Waynesboro Formation. The sandy 

dolomite of the Warrior Formation continues beyond the 

Rome trough into westernmost Pennsylvania, where it 

is estimated to be about 1,000 ft thick beneath drill hole 

7. An equivalent sequence of sandy dolomite and shale 

assigned to the Conasauga Group is present in northernmost West Virginia (beneath drill hole 6) and eastern 

Ohio (drill holes 1–5).

The Middle Cambrian age of the Pleasant Hill 

Formation and Middle to Late Cambrian age of the Warrior Formation, based on trilobite fauna (Wilson, 1952), 

indicate that these units are equivalent to the Conasauga 

Group in adjoining cross sections D–D′ and E–E′. The 

Conasauga Group in cross sections D–D′ and E–E′

is subdivided (in ascending order) into the Pumpkin 

Valley Shale, Rutledge Limestone, Rogersville Shale, 

Maryville Limestone, and Nolichucky Shale or equivalent units (Ryder and others, 2008, 2009). In cross 

section C–C′, the Pleasant Hill and Warrior Formations 

are tentatively recognized as stratigraphic equivalents of 

the Maryville Limestone and Nolichucky Shale of the 

Conasauga Group; however, in addition, the presence of 

lower Middle Cambrian fauna and abundant shale beds 

in the Pleasant Hill Formation (Wilson, 1952) suggests 

that part of the Pleasant Hill Formation may be equivalent to the Rogersville Shale. The absence of the Pumpkin Valley Shale and the Rutledge Shale of the Conasauga Group on cross section C–C′ may be due either 

to stratigraphic pinchout or to a facies change with the 

upper part of the Waynesboro Formation. Along the 

Blue Ridge front in south-central Pennsylvania, Maryland, and northeastern West Virginia, the Pleasant Hill 

and Warrior Formations are considered to be equivalent 

to the Middle and Upper Cambrian Elbrook Formation 

(Root, 1968; Brezinski, 1996).

On cross section C–C′, the Conasauga Group in 

northernmost West Virginia (beneath drill hole 6) and 

Ohio (drill holes 1–5) is subdivided into the Maryville 

Limestone and the overlying Nolichucky Shale in Ohio 

and its stratigraphic equivalent in West Virginia. The 

Maryville Limestone in Ohio, as used in this report and 

by Harris and others (2004) and Baranoski and others (2007), was formerly named the Rome Formation 

of Janssens (1973). Similarly, the Nolichucky Shale 

in Ohio was formerly named the Conasauga Formation of Janssens (1973). Both the Maryville Limestone 

and Nolichucky Shale in Ohio are now recognized as 

formations in the Conasauga Group (fig. 2).

The Conasauga Group and the overlying strata 

through the Trenton Limestone (Group) are interpreted 

as deposits of a post-rift passive-margin sequence, 

where Middle Ordovician continental-scale erosion (Knox unconformity) occurred during a drop in 

eustatic sea level and (or) tectonic uplift that preceded 

the Taconic orogeny (Read, 1989a,b). The Conasauga 

Group in the Rome trough in central West Virginia 

is interpreted as tidal-flat to shallow-water marine 

deposits (Donaldson and others, 1988). Moreover, the 

basal sandstone in the Warrior Formation (the unnamed 

sandstone member in the middle part of the Maryville 

Limestone in cross sections D–D′ and E–E′) probably 

was derived from a cratonic source to the north and 

northwest.

A complete 2,580-ft-thick section of the Upper 

Cambrian Gatesburg Formation was penetrated in drill 

hole 11. In this drill hole, the Gatesburg Formation rests 

conformably on the Warrior Formation and consists 

(in ascending order) of the following members: (1) the 

lower sandy member, which is an 870-ft-thick sandy 

dolomite with quartzarenite sandstone interbeds as 

thick as 5 ft; (2) the Ore Hill Limestone Member, which 

is a 190-ft-thick limestone with dolomite interbeds; 

(3) the upper sandy member, which is a 1,350-ft-thick 

sandy dolomite with quartzarenite sandstone interbeds 

as thick as 5 ft; and (4) the Mines Dolomite Member, 

which is a 165-ft-thick, chert-bearing dolomite. These 

members of the Gatesburg Formation and their cited 

thicknesses are consistent with the members reported in 

nearby outcrops (Wilson, 1952), except for the following: (1) the Stacy Dolomite Member (Wilson, 1952) 

at the base of the Gatesburg Formation is unrecognizable in drill hole 11 and has been combined with the 

lower sandy member in drill hole 11; and (2) the upper 

sandy member is about 600 ft thinner in outcrop than in 

drill hole 11. The Late Cambrian age of the Gatesburg 

Formation is based largely on trilobite fauna in the Ore 

Hill Limestone Member (Wilson, 1952).

The four members of the Gatesburg Formation 

recognized in drill hole 11 are correlated westward 

across the Valley and Ridge province (where the Mines 

Dolomite Member and the uppermost part of the upper 

sandy member were penetrated in drill hole 10) to 

the eastern part of the Rome trough (where the Mines 

Dolomite Member, the upper sandy member, equivalent beds of the Ore Hill Limestone Member, and the 

very uppermost part of the lower sandy member were 

penetrated in drill hole 9). In drill hole 9, the dominant 

lithology of the upper sandy member is quartzarenite sandstone rather than sandy dolomite as reported 

in drill hole 11 and adjoining outcrops. The facies 

change from predominantly dolomite to predominantly 

sandstone is interpreted to occur on cross section C–C′
Stratigraphic Framework 13

within 10 mi to the west of the master footwall ramp 

(thrust fault) of the Schellsburg dome. The Ore Hill 

Limestone and Mines Dolomite Members pinch out 

on cross section C–C′ in southwestern Pennsylvania 

about 11 and 27 miles, respectively, west of drill hole 9. 

Beyond these pinchout limits of the Ore Hill Limestone and Mines Dolomite Members, the Gatesburg 

Formation continues to the Pennsylvania border as 

the dolomite-dominated lower sandy member and the 

sandstone-dominated upper sandy member. The lower 

sandy member of the Gatesburg Formation rests conformably on the Warrior Formation between drill holes 

7 and 11, except near the crest of the northern extension 

of the Central West Virginia arch. The unconformity 

at the top of the Warrior Formation on the northern 

extension of the Central West Virginia arch and the 

previously mentioned unconformities at the base of the 

Warrior and Pleasant Hill Formations are shown on 

cross section C–C′ and are interpreted as having formed 

during recurrent uplift of the arch during the formation 

of the Rome trough.

In northernmost West Virginia, beneath drill hole 

6, Upper Cambrian rocks of the Gatesburg Formation 

change in nomenclature to the Copper Ridge Dolomite 

(equivalent stratigraphically to the lower sandy member 

of the Gatesburg Formation) and to the overlying 

Rose Run Sandstone (equivalent stratigraphically to 

the upper sandy member of the Gatesburg Formation). In Ohio, the stratigraphically equivalent Copper 

Ridge dolomite and Rose Run sandstone are defined 

as informal units within the Knox Dolomite (Slucher, 

2004). The Copper Ridge dolomite continues to the 

western end of cross section C–C′, whereas the Rose 

Run sandstone pinches out in eastern Ohio about 14 

mi west of drill hole 4. The Upper Cambrian rocks thin 

gradually westward across cross section C–C′, from the 

previously noted thickness of 2,580 ft for the Gatesburg 

Formation in drill hole 11 to about 150 ft for the Copper Ridge dolomite in drill hole 1.

The sandy members of the Gatesburg Formation and the Rose Run Sandstone (or sandstone) are 

interpreted as shallow-marine to peritidal deposits (Wilson, 1952; Riley and others, 1993). Also, the quartzarenite composition of the sandstone units suggests that they 

were derived from the craton (Riley and others, 1993).

In drill holes 1 and 2, a 100-ft-thick, silty to argillaceous and (or) sandy(?) dolomite unit in the middle 

of the Copper Ridge dolomite is correlated with the 

B zone of Calvert (1964) in Ohio. As described by 

Janssens (1973), the B zone is a glauconitic siltstone 

and very fine grained sandstone that forms a persistent 

marker bed over much of central Ohio. Janssens (1973) 

further reported that locally (such as in drill hole 1) the 

B zone contains a thin sandstone known informally as 

the Krysik sandstone. The B zone and the Krysik sandstone extend at least as far eastward in cross section 

C–C′ as drill hole 5 and probably underlie drill holes 6 

and 7 near the Ohio-West Virginia border and the West 

Virginia-Pennsylvania border.

The Cambrian Gatesburg Formation in cross 

section C–C′ is overlain conformably by the Lower 

and Middle Ordovician Beekmantown Group, which 

is a thick, widespread dolomite unit that is commonly 

anhydritic and contains (at least in the western half of 

the study area) the Middle Ordovician Knox unconformity (Wagner, 1966; Ryder and others, 1992). The 

Beekmantown Group is about 2,800 ft thick in the Valley and Ridge province (drill hole 10) and about 3,700 

ft thick in the eastern part of the Rome trough (drill 

hole 9). Westward across the Rome trough, the Beekmantown Group thins to about 1,500 ft at the western 

margin of the trough. In northernmost West Virginia 

and northeastern Ohio, stratigraphically equivalent 

units of the Beekmantown Group (Beekmantown 

Dolomite, or informal Beekmantown dolomite and the 

overlying Wells Creek formation) continue to thin in a 

westward direction. The Beekmantown Dolomite (as 

used in northernmost West Virginia) changes nomenclature in Ohio to the Beekmantown dolomite, which 

is an informal unit of the Knox Dolomite (Janssens, 

1973; Slucher, 2004). The Beekmantown Group and 

Beekmantown Dolomite (or dolomite) are interpreted 

as restricted-marine deposits that accumulated on a passive continental margin (Harris, 1973; Read, 1989a,b).

The informal Middle Ordovician Wells Creek formation (fig. 2) is an argillaceous dolomite that replaces 

(by a facies change) the upper anhydritic dolomite of 

the Beekmantown Group in the vicinity of the West 

Virginia-Pennsylvania border. The Wells Creek Formation was introduced in Ohio by Patchen and others 

(1985) and Wickstrom and others (1992) on the basis of 

the Wells Creek Dolomite, which was named by Lusk 

(1927) after a locality in western Tennessee. Wilson 

and Stearns (1968) discontinued the term in Tennessee when their geologic mapping failed to identify the 

Wells Creek Dolomite at the type locality. On cross 

section C–C′, however, the term Wells Creek formation is used (following Wickstrom and others, 1992), 

but its status is informal because its presence in the 

type area is uncertain. The upper anhydritic dolomite 

of the Beekmantown Group (equivalent to the Wells 

Creek formation) is also the approximate stratigraphic 

equivalent of the upper member of the Bellefonte Formation of the Beekmantown Group as used by Wagner 

(1966) and Berg and others (1983). In drill holes 5 and 

6, a thin, unnamed sandstone unit, which is probably 

equivalent to the St. Peter Sandstone, is located at the 

base of the Wells Creek formation.

The Middle Ordovician Knox unconformity is 

probably absent between the northern extension of 

the Central West Virginia arch and the eastern end of 

cross section C–C′, based on studies by Wagner (1966), 

Harris and Repetski (1982), and Mussman and others 

(1988); however, the unconformity is very likely present between the upper and middle anhydritic dolomite 

units in the upper part of the Beekmantown Group at 

about 17,800 ft depth in drill hole 9. The Knox unconformity continues from drill hole 9 to the western 

end of the cross section and accounts for at least part 

of the regional thinning of the underlying Cambrian 

and Lower Ordovician strata. In Ohio, the unconformity cuts downsection and places the Wells Creek 

formation on successively older rocks as follows: the 
14 Geologic Cross Section C–C’ Through the Appalachian Basin

Beekmantown dolomite is truncated by the unconformity about 4 mi east of drill hole 4; the Rose Run 

sandstone is truncated by the unconformity about 14 mi 

west of drill hole 4; and the B zone and Krysik sandstone interval is partially truncated by the unconformity 

in drill hole 1 to within 70 ft of the base of the interval.

The Beekmantown Group (in Pennsylvania) and 

the Wells Creek formation (in Ohio and West Virginia) 

are overlain conformably by a widespread Upper 

Ordovician limestone-dominated interval that extends 

across the entire cross section. This limestone interval 

varies in thickness from about 1,100 ft in the Valley and 

Ridge province (drill hole 10) to about 1,450 ft above 

the eastern part of the Rome trough (drill hole 9). West 

of the Rome trough, the thickness of the limestone 

interval thins gradually to about 900 ft in northernmost West Virginia (drill hole 6) and to about 600 ft 

in north-central Ohio (drill hole 1). On the basis of the 

nomenclature used in the Valley and Ridge outcrop belt 

(Rones, 1969; Laughrey and others, 2003) and in the 

subsurface near drill hole 10 (Wagner, 1966), the limestone interval in drill holes 9 and 10 is divided into the 

following units (in ascending order): (1) the Middle to 

Upper Ordovician Loysburg Formation, (2) the Upper 

Ordovician Black River Group, and (3) the Upper 

Ordovician Trenton Group. The Black River and Trenton Groups (Trenton Limestone in West Virginia and 

Ohio) are recognized across the entire cross section, 

whereas the Loysburg Formation only extends as far 

west as drill hole 6 in northernmost West Virginia. The 

Loysburg Formation pinches out into the Black River 

Group near the Ohio-West Virginia border. Formations 

in the Black River Group (Hatter, Snyder, and Linden 

Hall Formations) and in the Trenton Group (Nealmont, 

Salona, and Coburn Formations) in Pennsylvania have 

been identified by Wagner (1966), Rones (1969), and 

Laughrey and others (2003); however, because the 

formation contacts were not identified in the drill holes, 

labels showing the relative positions of these formations are shown but their contacts are not drawn on 

cross section C–C′.

Across Ohio, northernmost West Virginia, and 

western Pennsylvania, the Black River Group and 

Trenton Limestone (or Group) are characterized by a 

homogeneous lithology (Riley and others, 2006). In 

this part of the cross section, the Black River Group 

consists largely of carbonate mudstone and wackestone, whereas the Trenton Limestone (Group) consists 

largely of fossiliferous, argillaceous limestone (wackestone, packstone, and grainstone). Also, as shown 

on the cross section and in figure 2, two widespread 

potassium bentonite beds (α and β marker beds of Stith, 

1979; Millbrig and Deicke Bentonite Beds of Huff and 

Kolata, 1990; Kolata and others, 1996) are located in 

the uppermost part of the Black River Group in Ohio. 

In the eastern part of the cross section, the Millbrig 

Bentonite Bed (α marker) either defines the Black 

River-Trenton contact or is located 10 to 20 ft below 

the contact (a relation that cannot be shown at the scale 

of the cross section). Near the Ohio-West Virginia 

border, the contact between the characteristic carbonate 

mudstone of the Black River Group and the characteristic fossiliferous argillaceous grainstone of the Trenton Group is located about 110 ft below the Millbrig 

Bentonite Bed, thus shifting the location of the Black 

River-Trenton contact from a younger stratigraphic 

position farther west to an older stratigraphic position 

at this location. This downsection shift of the Black 

River-Trenton contact is first documented in drill hole 

6, where the Trenton Limestone is about 260 ft thick 

and consists of a lower unit of fossiliferous wackestone and packstone and an upper unit of argillaceous 

fossiliferous grainstone. These two units in the Trenton 

Limestone correlate, respectively, with the Nealmont 

Formation and the Salona and Coburn Formations, 

undivided, in central Pennsylvania (Wagner, 1966; 

Laughrey and others, 2003). The zone across which 

initial eastward thickening of the Trenton Limestone 

takes place, because of the downsection shift of the 

Black River-Trenton contact, coincides approximately 

with a northeast-trending ramp margin proposed by 

Riley and others (2006). East of this proposed ramp 

margin, the limestone of the Black River and Trenton 

Groups becomes more argillaceous and fossiliferous. In 

central Pennsylvania about 50 mi north of cross section 

C–C′, the Black River-Trenton contact has shifted even 

farther downsection (by about 100 ft), so that both the 

Millbrig and Deicke Bentonite Beds, as well as many 

other bentonite beds, are present in the Trenton Group 

(Cullen-Lollis and Huff, 1986; Kolata and others, 

1996; Laughrey and others, 2003). The LoysburgBlack River-Trenton interval in central Pennsylvania 

is characterized by the following lithologic units: (1) 

the Loysburg Formation, which consists of interbedded 

to interlaminated calcareous and dolomitic mudstone 

with minor amounts of wackestone, packstone, and 

grainstone (Rones, 1969; Laughrey and others, 2003); 

(2) the Black River Group, which consists of calcareous mudstone commonly interbedded with skeletal 

wackestone, packstone, and grainstone (Rones, 1969; 

Laughrey and others, 2003); and (3) the Trenton Group 

consists of skeletal wackestone, packstone, and grainstone interbedded with argillaceous calcareous mudstone and dark-gray to black shale (Thompson, 1963; 

Laughrey and others, 2003).

The dolomitic limestone of the Loysburg Formation is interpreted as peritidal deposits, whereas the 

limestone of the Black River and Trenton Groups is 

interpreted as subtidal-carbonate-ramp and deeper 

water carbonate-ramp to shelf-margin deposits, respectively (Laughrey and others, 2003; Riley and others, 

2006). The potassium bentonite beds are thought to be 

derived from extensive volcanic ash falls that occurred 

during the Late Ordovician phase of the Taconic orogeny (Huff and Kolata, 1990; Huff and others, 1992).

Upper Ordovician to Lower Silurian 

Siliciclastic Strata

The Upper Ordovician to Lower Silurian siliciclastic strata are characterized by gray shale, red 

shale, sandstone, and black shale (fig. 2). As shown 
Stratigraphic Framework 15

on cross section C–C′, the combined thickness of the 

strata ranges from about 5,000 ft in the vicinity of the 

Allegheny structural front (near drill hole 10) (also see 

isopach maps by Diecchio, 1985) to about 1,300 ft near 

drill holes 1 and 2. In the south-central Pennsylvania 

part of cross section C–C′, the Upper Ordovician to 

Lower Silurian siliciclastic strata consist of the following units (in ascending order): the Antes Shale, Reedsville Shale, Bald Eagle Formation, Juniata Formation, 

Tuscarora Formation (or Medina Group in western 

Pennsylvania), and Rose Hill Formation (Berg and others, 1983; Ryder and others, 1992) (fig. 2). In Ohio, the 

Upper Ordovician to Lower Silurian siliciclastic strata 

change nomenclature as follows: (1) the Utica Shale 

replaces the Antes Shale (Ryder and others, 1992), 

(2) the informally used Cincinnati group replaces the 

Reedsville Shale (Slucher, 2004), (3) the informal 

Medina sandstone, Cabot Head Shale, and informal 

“Clinton”1 sandstone interval replaces the Tuscarora 

Formation or Medina Group (Ryder, 2004), and (4) the 

unnamed and undivided Lower Silurian carbonate and 

shale unit and the overlying Rochester Shale replace 

the Rose Hill Formation (Ryder, 2004) (fig. 2). The 

change in nomenclature from the Juniata Formation 

in southwestern Pennsylvania to the Queenston Shale 

in western Pennsylvania (Berg and others, 1983) and 

Ohio (Ryder and others, 1992; Slucher, 2004) occurs 

approximately 30 miles west of drill hole 8.

The Upper Ordovician to Lower Silurian siliciclastic strata are interpreted as being derived from 

an eastern orogenic source and deposited in a rapidly subsiding foreland basin. This foreland basin 

and its sedimentary deposits are associated with the 

1

The “Clinton” sandstone in Ohio was miscorrelated by drillers 

with strata in the type Clinton Group of New York when in fact it 

is equivalent to the underlying type Medina Group of New York. 

Although this miscorrelation has caused confusion in nomenclature, 

the term continues to be used widely in the literature and by the 

oil and gas industry. Early drillers correctly identified the informal 

Medina sandstone in Ohio as a partial equivalent of the type Medina 

Group of New York.

continent-island arc collision of the Taconic orogeny 

(Colton, 1970; Milici and de Witt, 1988; Drake and others, 1989; Pavlides, 1989; Faill, 1997a).

The Upper Ordovician Antes (or Utica) Shale is a 

black shale unit that extends across cross section C–C′

and ranges in thickness from about 300 ft in drill hole 

2 to about 700 ft in the eastern part of the Rome trough 

(drill hole 9). Upper Ordovician strata that overlie the 

Antes (or Utica) Shale consist of the Reedsville Shale 

(or Cincinnati group) (gray shale, siltstone, and minor 

sandstone with increasing amounts of limestone in 

Ohio), the Bald Eagle Formation (sandstone, siltstone, 

and gray shale), and the Juniata Formation (or Queenston Shale) (red beds). The widespread Cherokee 

unconformity is present at the top of the Juniata Formation (or Queenston Shale) (Hettinger, 2001; Ryder, 

2004). According to Dennison and Head (1975), the 

Cherokee unconformity resulted from a fall in eustatic 

sea level that probably was independent of the Taconic 

orogeny and the resultant classic angular unconformity 

between Upper Ordovician and Lower Silurian rocks in 

eastern Pennsylvania (Pavlides and others, 1968).

The Antes (or Utica) Shale is interpreted as an 

anoxic deposit that accumulated in the distal part of the 

Taconic foreland basin during initial deepening of the 

carbonate platform (the underlying Black River Group 

and Trenton Group (or Limestone)) (Castle, 2001), 

whereas the overlying Reedsville Shale (or Cincinnati 

group), Bald Eagle Formation, and the Juniata Formation (or Queenston Shale) are interpreted as shallowmarine and intertidal deposits that accumulated on 

a prograding clastic wedge (Diecchio, 1985; Castle, 

2001).

Lower Silurian siliciclastic strata overlie the 

Juniata Formation (or Queenston Shale) red beds from 

the Allegheny structural front and adjoining Valley and 

Ridge province westward into north-central Ohio. The 

eastern part of the Lower Silurian siliciclastic strata is 

named the Tuscarora Formation, which is about 450 to 

500 ft thick (including a 100-ft-thick Tuscarora-Juniata 

transition zone) where it intersects cross section C–C′

in south-central Pennsylvania (drill holes 8–10). The 

Tuscarora Formation grades westward into siliciclastic 

strata of the Lower Silurian Medina Group in western 

Pennsylvania (drill hole 7) and of the Lower Silurian 

“Clinton” sandstone and the underlying Cabot Head 

Shale and Medina sandstone in Ohio (drill holes 3–5) 

and along the northernmost West Virginia border (drill 

hole 6). The Medina sandstone, Cabot Head Shale, 

and “Clinton” sandstone have a combined thickness of 

approximately 200 ft (Ryder, 2000, 2004). The Tuscarora Formation has a greater percentage of net sandstone and is typically coarser grained than the Medina 

Group or the combined Medina sandstone-Cabot Head 

Shale-“Clinton” sandstone. Between drill holes 2 and 

3, the “Clinton” sandstone pinches out westward due 

to a facies change and is replaced by the Cabot Head 

Shale. Furthermore, in this same locality, the Medina 

sandstone is replaced by the Lower Silurian Brassfield 

Limestone, which continues to the northwestern end 

of the cross section. The Tuscarora-Medina-“Clinton” 

interval is interpreted as a combined shallow-marineshelf, shoreface, and fluvial-to-estuarine deposit 

(Castle, 1998; Hettinger, 2001; Ryder, 2004) that accumulated as molasse during the Early Silurian late-stage 

uplift of the Taconian orogenic belt (Dorsch and others, 

1994).

The 250- to 750-ft-thick Lower Silurian Rose Hill 

Formation conformably overlies the Medina Group or 

the Tuscarora Sandstone in drill holes 7 through 10. 

The Rose Hill Formation consists of gray shale, red 

shale, dolomite, and limestone (Hettinger, 2001; Ryder, 

2004). About midway between drill holes 7 and 8, the 

lower part of the Rose Hill Formation changes to a 

predominantly dolomite interval that continues westward to the Pennsylvania-West Virginia border between 

drill holes 6 and 7 and into Ohio as far as between drill 

holes 3 and 4. In northernmost West Virginia (drill hole 

7) and northeastern Ohio (drill hole 5), the Rose Hill 

Formation is replaced by the Lower Silurian Rochester 

Shale and an underlying unit of thin dolomite, limestone, and interbedded gray shale identified on cross 
16 Geologic Cross Section C–C’ Through the Appalachian Basin

section C–C′ as “Lower Silurian carbonates and shales, 

undivided” (Ryder, 2000, 2004) (fig. 2). The combined 

Lower Silurian carbonates and shales unit and the 

Rochester Shale overlie the “Clinton” sandstone and 

thin to about 150 ft thick in drill hole 5 and to about 50 

ft thick in drill hole 1. Kleffner (1985), Brett and others 

(1990), Hettinger (2001), and Slucher (2004) recognized an unconformity at the base of the Lower Silurian 

Dayton Limestone, which is included in the Lower 

Silurian carbonates and shales unit. This unconformity 

extends across much of northeastern Ohio and probably also extends into the Rose Hill Formation at least 

as far east as somewhere between drill holes 10 and 11. 

A thin, continuous, locally hematitic sandstone (known 

as the Lower Silurian Keefer Sandstone) conformably 

overlies the Rose Hill Formation and Rochester Shale 

across northernmost West Virginia and Pennsylvania 

(fig. 2). The Rose Hill Formation is interpreted as a 

shallow-marine-shelf deposit (Smosna and Patchen, 

1978).

Lower Silurian to Middle Devonian 

Carbonate and Evaporite Strata

Lower Silurian to Middle Devonian strata consist of a lithologically varied interval of limestone, 

dolomite, sandstone, gray shale, chert, anhydrite, and 

halite (fig. 2). The combined thickness of these stratigraphic units ranges from about 2,500 to 3,000 ft, 

respectively, in drill holes 9 and 8, to about 1,150 ft in 

drill hole 1. In the vicinity of the Allegheny structural 

front and adjoining Valley and Ridge province (drill 

hole 10), the thickness of the Lower Silurian to Middle 

Devonian strata is about 2,150 ft (Heyman, 1977). 

In the far eastern part of the section in Pennsylvania, 

the typical stratigraphic units in this interval are as 

follows (in ascending order): McKenzie Member of 

the Mifflintown Formation, Bloomsburg Formation, 

Wills Creek Formation, Tonoloway Formation, Keyser 

Formation, New Creek Limestone, Corriganville 

Limestone, Mandata Shale, Shriver Formation, Ridgeley Sandstone, Needmore Shale, and Onondaga Formation (Berg and others, 1983) (fig. 2). These stratigraphic 

units extend westward through the rest of Pennsylvania 

into northernmost West Virginia and Ohio, but are 

assigned different names in different parts of the section. The McKenzie Limestone Member of the Mifflintown Member is equivalent to the Lockport Formation from western Pennsylvania westward. The Wills 

Creek Formation is equivalent to the lower part of the 

Salina Group from western Pennsylvania westward. 

The Tonoloway Formation is replaced by the upper part 

of the Salina Group from southwestern Pennsylvania 

westward. The Silurian part of the Keyser Formation 

(Keyser Limestone in West Virginia) correlates with the 

Silurian Bass Islands Dolomite in Ohio. The Shriver 

Formation is replaced by the Licking Creek Limestone 

in south-central Pennsylvania. The Keyser Formation, New Creek Limestone, Corriganville Limestone, 

Mandata Shale, and Licking Creek Limestone in Pennsylvania are mapped as formations in the Helderberg 

Group in northernmost West Virginia; the New Creek 

Limestone, Corriganville Limestone, Mandata Shale, 

and Licking Creek Limestone in Pennsylvania correlate 

with the Helderberg Limestone in Ohio. The Ridgeley 

Sandstone in Pennsylvania correlates with the Oriskany 

Sandstone in northernmost West Virginia and Ohio. The 

upper part of the Needmore Shale is replaced by the 

Huntersville Chert in south-central Pennsylvania. The 

Needmore, Huntersville, and Onondaga Formation (or 

Limestone) in Pennsylvania and West Virginia correlate 

with the Onondaga Limestone in northeastern Ohio or 

with the interval that includes the Bois Blanc Formation, Detroit River Group, Columbus Limestone, and 

Delaware Limestone in north-central Ohio (fig. 2).

The Lower and Upper Silurian Lockport Dolomite in Ohio rests conformably on either the Rochester 

Shale or the Lower Silurian Keefer Sandstone, whereas 

the equivalent McKenzie Member of the Mifflintown 

Formation in Pennsylvania rests conformably on just 

the Keefer Sandstone (fig. 2). The Lockport Dolomite 

consists largely of fine to medium crystalline dolomite, 

several widespread vuggy rubble zones, and local bioherms (Multer, 1963; Santini and Coogan, 1983; Noger 

and others, 1996). By comparison, the McKenzie Member consists of carbonate mudstone and fossiliferous 

wackestone to grainstone interbedded with greenishgray to black shale (Knowles, 1966; de Witt, 1974). 

In drill hole 10, the McKenzie Member is divided 

into upper and lower parts by a thin red-bed unit that 

probably correlates with the Rabble Run Member of 

the Mifflintown Formation (Hoskins, 1961). The facies 

change from limestone and shale of the McKenzie 

Member to crystalline and vuggy dolomite of the Lockport Dolomite occurs in southwestern Pennsylvania 

about 20 mi northwest of drill hole 8.

The McKenzie Member of the Mifflintown Formation is conformably overlain by the Upper Silurian 

Bloomsburg Formation, which is characterized by 

grayish-red shale, mudstone, and sandstone (Hoskins, 

1961; Knowles, 1966; de Witt, 1974). The Bloomsburg 

Formation is 30 to 60 ft thick and extends from outcrops on the flanks of the Wills Creek anticline, through 

drill holes 8 and 9, to a pinchout approximately 8 mi 

west of drill hole 8.

The Upper Silurian Salina Group and the equivalent Wills Creek and overlying Tonoloway Formations 

constitute a well-defined unit that extends across all of 

cross section C–C′ and ranges in thickness from about 

1,000 ft near the Allegheny structural front (drill hole 

10), to about 1,850 ft in southwestern Pennsylvania 

(drill hole 8), to about 600 ft in north-central Ohio 

(drill holes 1 and 2). The Salina Group consists largely 

of anhydritic dolomite, shale, anhydrite, and halite 

with the halite-bearing part concentrated in drill holes 

3 through 9 near the western and southern margins 

of the Salina salt basin as defined by Colton (1970), 

Clifford (1973), Frey (1973), and Smosna and others 

(1977). Halite-bearing intervals in drill holes 3 through 

9 are interpreted from geophysical and lithologic logs 

and from halite beds previously identified by Clifford (1973) and Heyman (1977). Most halite-bearing 
Stratigraphic Framework 17

intervals shown on section C–C′, such as the approximately 600-ft-thick interval in drill hole 5, are not 

composed entirely of halite but instead are intervals 

of interbedded halite, dolomite, shale, and anhydrite. 

As shown by Frey (1973) and Scanlin and Engelder 

(2003), the halite and shale intervals in the Salina 

Group are commonly overthickened because of flowage 

into the cores of thin-skinned anticlines.

Eastward from a location about 18 mi west of drill 

hole 8, the lower part of the Salina Group is replaced 

by argillaceous dolomite and gray shale or mudstone 

of the Upper Silurian Wills Creek Formation. Farther 

eastward, beginning at about drill hole 9, the remainder of the Salina Group is replaced by argillaceous to 

anhydritic limestone and dolomite of the Upper Silurian 

Tonoloway Formation. From a location between drill 

hole 1 to within about 20 mi of drill hole 8, the Salina 

Group rests conformably on the Lockport Dolomite. 

Between drill hole 8 and the eastern end of the cross 

section, the Wills Creek Formation rests conformably 

on the Bloomsburg Formation.

The Late Silurian to earliest Devonian Keyser 

Formation contains the youngest Silurian sediments in 

the cross section; most of the Keyser Formation is of 

Silurian age, based on conodont studies (Denkler and 

Harris, 1988; Baez Rodríguez, 2005). In south-central 

and southwestern Pennsylvania, the Keyser Formation consists of argillaceous carbonate mudstone and 

fossiliferous grainstone (Knowles, 1966; de Witt, 1974) 

that grade into dolomite in western Pennsylvania. In 

northernmost West Virginia, the dolomite is known 

as the Keyser Limestone of the Helderberg Group. 

The majority of the Keyser Formation (or Limestone) 

in Pennsylvania and northernmost West Virginia is 

equivalent to the Upper Silurian Bass Islands Dolomite 

in Ohio, an argillaceous dolomite (80 feet thick or less) 

that extends to the western end of the cross section.

The overall depositional setting of the Lower and 

Middle Devonian carbonate and evaporite rocks was a 

shallow basin with closed circulation where evaporites 

were surrounded by a carbonate shelf with normal sea 

water where limestone was deposited (Smosna and 

others, 1977). Dolomites and evaporite beds of the 

Upper Silurian Salina Group that conformably overlie 

the Lockport Dolomite signal an abrupt change on 

the carbonate shelf from normal circulation to greatly 

restricted circulation caused by a change to a very arid 

climate (Cecil and others, 2004). The Salina Group is 

interpreted as a shallow-water and sabkha (supratidal) 

deposit (Tomastik, 1997). Because halite beds in the 

Salina Group terminate abruptly against the Cambridge 

structural discontinuity (about 25 mi south of cross 

section C–C′; fig. 1), Root (1996) suggested that this 

structure (during the time of Salina deposition) was a 

topographic sill that separated hypersaline, halite-precipitating sea water on the east from less saline water 

on the west. An alternate explanation for the abrupt 

termination of the halite beds is offered by Farmerie 

and Coogan (1995), who suggested that the halite beds 

originally extended westward across the Cambridge 

structural discontinuity and later were dissolved by 

downward-percolating ground water from a Lower 

Devonian erosion surface (the unconformity at the 

base of the Oriskany Sandstone, discussed later in this 

section). Both explanations, however, require positive 

relief on the Cambridge structural discontinuity during 

the Silurian.

Lower Devonian limestones in cross section C–C′

constitute a composite unit that ranges in thickness 

from about 300 ft in drill hole 10, to about 200 ft in 

drill hole 6, and to a pinch-out edge midway between 

drill holes 2 and 3. In Pennsylvania and northernmost 

West Virginia, the New Creek and Corriganville Limestones near the base of the composite unit consist of 

wackestone, packstone, and skeletal grainstone, and the 

Licking Creek Limestone at the top of the composite 

unit consists of slightly fossiliferous calcareous mudstone with local chert (de Witt, 1974; Harper, 1999). 

The Corriganville is overlain by the thin, dark-gray to 

black Mandata Shale (Harper, 1999). In the far eastern part of the section, the Shriver Formation overlies 

the Mandata, but the Shriver grades several miles 

east of drill hole 9 to the Licking Creek Limestone. 

The Shriver Formation consists of silty limestone and 

siliceous shale with abundant chert (Knowles, 1966; de 

Witt, 1974; Harper, 1999). The equivalent Helderberg 

Limestone in Ohio rests unconformably on the Bass 

Islands Dolomite (Patchen and others, 1985; Slucher, 

2004) and extends westward to a point between drill 

holes 2 and 3, where it is truncated by an unconformity 

at the base of the Oriskany Sandstone. These Helderberg strata are generally interpreted as normal marine 

deposits that accumulated in an intracratonic basin and 

on flanking carbonate shelves (Smosna, 1988).

The clean, quartzose Lower Devonian Ridgeley 

Sandstone (or equivalent Oriskany Sandstone) overlies 

the Helderberg Limestone (or Group), and extends 

across most of cross section C–C′ (see also Abel and 

Heyman, 1981, for the Pennsylvania part of the section). Regional unconformities at the top and base of 

the Ridgeley (or Oriskany) Sandstone probably were 

caused by falls in eustatic sea level (Dennison and 

Head, 1975). Of the two unconformities, Dennison and 

Head (1975) considered the upper one to represent the 

longer period of emergence and perhaps the greater 

decrease in water depth. This post-Oriskany unconformity probably truncated the Oriskany Sandstone 

between drill holes 2 and 3 near the pinchout mapped 

by Opritza (1996). West of where the Oriskany pinches 

out, the two unconformities merge and cut progressively downsection across the Helderberg Limestone 

and the uppermost part of the Bass Islands Dolomite. 

The Oriskany Sandstone has been interpreted as a 

shallow-marine deposit (Bruner, 1988; Harper and 

Patchen, 1996), although Cecil (2004a,b) suggested an 

earlier eolian provenance for the Oriskany Sandstone 

and adjacent chert beds (Shriver Formation and Huntersville Chert).

In drill holes 1 and 2, a 50- to 60-ft-thick sandstone and cherty carbonate unit unconformably overlies 

the Salina Group and is unconformably overlain by the 

Middle Devonian Detroit River Group (as suggested 

by regional correlations of Dow, 1962; Slucher, 2004). 
18 Geologic Cross Section C–C’ Through the Appalachian Basin

In this report, the sandstone and cherty carbonate unit 

is correlated with the Lower Devonian Bois Blanc 

Formation, which is recognized in northern Ohio by 

Dow (1962), Janssens (1968), Rickard (1984), Sparling 

(1988), and Slucher (2004); however, several other 

possibilities exist. For example, the sandstone and 

cherty carbonate unit might correlate with the Lower 

Devonian Sylvania Sandstone in northwestern Ohio 

and southwestern Ontario (Carman, 1936; Dow, 1962; 

Slucher, 2004) or with the Lower Devonian Hillsboro 

Sandstone in central and southwestern Ohio (Hansen, 

1999; Slucher, 2004). To further complicate the correlation, the Sylvania and Hillsboro Sandstones might be 

stratigraphically equivalent units.

In the Pennsylvania and northernmost West 

Virginia part of cross section C–C′, the Ridgeley (or 

Oriskany) Sandstone is overlain unconformably by 

a thin, black shale, which is mapped as the Middle 

Devonian Needmore Shale (de Witt, 1974; Harper 

and Patchen, 1996). This shale, in turn, is conformably overlain by a chert-dominated, silty limestone 

(calcareous mudstone), which is mapped as the 

Middle Devonian Huntersville Chert (Diecchio and 

others, 1984; Flaherty, 1996; Harper and Patchen, 

1996). Furthermore, the Huntersville Chert is overlain 

by a thin, argillaceous limestone, which is mapped as 

the Middle Devonian Onondaga Limestone (Flaherty, 

1996; Harper and Patchen, 1996). East of drill hole 

10, the Huntersville Chert is replaced by the black 

shale of the Needmore Shale (de Witt, 1974; Flaherty, 

1996; Harper and Patchen, 1996). Near the Ohio-West 

Virginia border, the Huntersville Chert intertongues 

with argillaceous, slightly fossiliferous limestone that 

extends into Ohio as the Onondaga Limestone (fig. 2). 

Moreover, the thin Onondaga Limestone at the top of 

the Huntersville Chert in Pennsylvania and northernmost West Virginia becomes the uppermost part of the 

Onondaga Limestone in Ohio. In east-central Ohio, 

between drill holes 2 and 3, the Onondaga Limestone 

is replaced by the Middle Devonian Columbus Limestone and the overlying Middle Devonian Delaware 

Limestone. The Columbus and Delaware Limestones 

may be separated by an unconformity (Hansen, 1999; 

Slucher, 2004).

Middle Devonian to Lower Mississippian 

Siliciclastic Strata

Middle Devonian to Lower Mississippian siliciclastic strata include black shale, gray shale, sandstone, 

red beds, and minor argillaceous limestone (fig. 2). 

The Middle Devonian to Lower Mississippian strata 

shown in cross section C–C′ thin dramatically westward from as much as about 7,900 ft in south-central 

Pennsylvania (beneath the No. 1 Lehman drill hole) to 

about 4,300 ft in western Pennsylvania (drill hole 7), 

and to about 1,850 ft in north-central Ohio (drill hole 

3). From several miles east of drill hole 9 to the flanks 

of the Schellsburg dome near drill hole 10 in southcentral Pennsylvania, the Middle Devonian to Lower 

Mississippian siliciclastic strata include the following 

units (and their equivalents, in ascending order): (1) the 

Middle Devonian Hamilton Group (Marcellus Formation and Mahantango Formation); (2) the Middle Devonian Tully Limestone; (3) the Upper Devonian Harrell 

Formation, Brallier Formation, Scherr Formation, 

Foreknobs Formation (Harper, 1993) (equivalent to the 

Greenland Gap Group of Dennison (1970) in cross section D–D′ (Ryder and others, 2009)), and Catskill Formation (Harper, 1993) (Hampshire Formation as used 

by de Witt (1974)); (4) the Upper Devonian and Lower 

Mississippian Rockwell Formation (Harper, 1993); 

and (5) the Lower Mississippian Burgoon Sandstone 

(equivalent to the Price Formation in cross section 

D–D′ (Ryder and others, 2009)) (Brezinski, 1999). The 

Scherr Formation, Foreknobs Formation, and Catskill 

Formation cross an arbitrary boundary near drill hole 9 

and the Laurel Hill anticline, beyond which the formations are mapped as the Elk Group, Bradford Group, 

and Venango Group, respectively. The Elk, Bradford, 

and Venango Groups, which were first mentioned as 

informal sand groups (Wilmarth, 1938), were formalized into stratigraphic nomenclature by Harper and 

Laughrey (1987), Harper (1993), and Harper and others 

(1999).

In western Pennsylvania, northernmost West 

Virginia, and eastern to north-central Ohio, the Middle 

Devonian to Lower Mississippian strata include the following units (in ascending order): the Middle Devonian 

Hamilton Group (Marcellus Shale and Mahantango 

Formation; equivalent to the Plum Brook Shale and 

overlying Prout Limestone) and Tully Limestone; the 

Upper Devonian Genesee Formation and Sonyea Formation (which are in turn stratigraphically equivalent to 

the Harrell Formation to the east); the Upper Devonian 

West Falls Formation (which includes the Rhinestreet 

Shale and Angola Shale Members), Java Formation 

(and the partially equivalent Olentangy Shale), Huron 

Member of the Ohio Shale (or partially equivalent 

Dunkirk Shale Member of the Perrysburg Formation) 

(as shown by de Witt and others, 1993), Chagrin Shale 

(which is equivalent to the upper part of the Brallier 

Formation, the Scherr, Foreknobs, and Hampshire Formations, and the lower part of the Rockwell Formation 

to the east and to the Cussewago Sandstone, Bedford 

Shale, and Ohio Shale to the west); the Upper Devonian Berea Sandstone and the Lower Mississippian 

Sunbury Shale (which are equivalent to the lower part 

of the Rockwell Formation); the Lower Mississippian 

Cuyahoga Formation; and the Lower Mississippian 

Shenango Formation. The top of the 30- to 40-ft-thick 

Tully Limestone, which is located between the Mahantango Formation and the Harrell Formation or Genesee 

Formation, marks the top of the Middle Devonian on 

cross section C–C′.

The Upper Devonian to Lower Mississippian 

siliciclastic strata are interpreted as sediments derived 

from an easterly orogenic source and deposited in a 

rapidly subsiding foreland basin. This foreland basin 

and its sedimentary deposits (the Catskill delta complex 

of Woodrow and Sevon (1985) and Harper (1999); and 

the Price-Rockwell delta complex of Boswell, Heim, 
Stratigraphic Framework 19

and others (1996) are associated with the Acadian orogeny (Colton, 1970; Milici and de Witt, 1988; Osberg 

and others, 1989; Faill, 1997b).

The stratigraphy of the Middle and Upper Devonian black shales has been studied in great detail 

because of the role of black shales as hydrocarbon 

source rocks and reservoirs (Roen and Kepferle, 1993). 

In the vicinity of the Allegheny structural front and the 

adjoining Valley and Ridge province, the lowermost 

of the Devonian black shales is the Middle Devonian 

Marcellus Formation, which rests conformably on the 

Middle Devonian Onondaga Formation. Also in this 

region, the Marcellus Formation and the Onondaga 

Formation are commonly separated by the widespread 

Tioga Ash Bed (Inners, 1979; Way and others, 1986; 

Harper and Patchen, 1996) (Tioga Bentonite of Dennison and Head, 1975) (fig. 2). The Marcellus Formation (or Shale) and the overlying gray shale of the 

Mahantango Formation of the Hamilton Group extend 

across Pennsylvania, northernmost West Virginia, and 

eastern Ohio in cross section C–C′ (Patchen and others, 

1985; Slucher, 2004). The Marcellus Shale pinches 

out between drill holes 2 and 3, but the Mahantango 

Formation of the Hamilton Group continues into northcentral Ohio as a gray shale and limestone unit recognized as the undivided Middle Devonian Plum Brook 

Shale and the Prout Limestone (Rickard, 1984; Slucher, 

2004).

The Harrell Formation and the overlying Brallier 

Formation (from several miles east of drill hole 9 to the 

flanks of the Schellsburg dome near drill hole 10) consist of dark-gray shale and gray, silty shale or siltstone, 

respectively. The Harrell Formation rests unconformably (Middle to Late Devonian unconformity described 

in the following paragraph) on the Tully Limestone 

and crosses an arbitrary boundary near drill hole 8 

into the Genesee and Sonyea Formations. The Brallier 

Formation conformably overlies the Harrell Formation 

to within 4 to 5 mi east of drill hole 8, where it conformably overlies the Sonyea Formation. About 25 mi 

west of drill hole 8, the Brallier Formation crosses an 

arbitrary boundary into rocks of the Chagrin Shale. The 

Chagrin Shale (1) continues westward from the arbitrary boundary; (2) intertongues with and climbs over 

the Rhinestreet and Angola Shale Members of the West 

Falls Formation, the Java Formation, and the Huron 

Member of the Ohio Shale; and (3) is replaced by the 

Three Lick Bed of the Ohio Shale at the western end 

of the cross section (drill holes 1 and 2). The Harrell 

Formation is interpreted as an offshore-marine (basin) 

deposit, whereas the Brallier Formation is interpreted 

as a marine-basin-slope to turbidite-slope to delta-front 

deposit (Lundegard and others, 1985; Harper, 1999). 

The black shales of the Marcellus Formation, Rhinestreet Shale Member, Huron Member, and Dunkirk 

Member are interpreted as anoxic deposits (Boswell, 

1996; Harper, 1999).

A regional Middle to Late Devonian unconformity, 

described and mapped by de Witt and others (1993), is 

present throughout all of cross section C–C′ at the top 

of the Tully Limestone and at the top of the Hamilton 

Group where the Tully Limestone is absent (fig. 2). 

Westward from drill hole 6, where the partially eroded 

Tully Limestone is overlain by the Upper Devonian 

Genesee Formation, successively younger Upper Devonian strata downlap on the Middle to Late Devonian 

unconformity. For example, in drill hole 5, the Upper 

Devonian Sonyea Formation rests unconformably on 

the Hamilton Group, whereas farther west, in drill holes 

3 and 4, the Upper Devonian Rhinestreet Shale Member of the West Falls Formation rests unconformably 

on the Hamilton Group. Furthermore, in drill holes 1 

and 2, the upper part of the Upper Devonian Olentangy 

Shale, which is equivalent to the Java Formation, rests 

unconformably on the Plum Brook Shale and the Prout 

Limestone.

The Scherr and Foreknobs Formations (which 

are present from several miles east of drill hole 9 to 

the flanks of the Schellsburg dome near drill hole 10) 

consist of sandstone, silty and argillaceous sandstone, 

and siltstone, whereas the overlying Catskill Formation in the same region consists of red beds of silty 

sandstone, siltstone, and silty shale. In the vicinity of 

the Negro Mountain anticline, several red bed tongues 

of the Catskill Formation extend into the upper part of 

the Foreknobs Formation. In southwestern Pennsylvania, the equivalent Elk, Bradford, and Venango Groups 

were used by Harper and Laughrey (1987), Harper 

(1993), and Harper and others (1999) and correlate 

approximately with the informal Elk, Bradford, and 

Venango “plays” recognized by Donaldson and others (1996); Boswell, Thomas, and others (1996); and 

Boswell, Heim, and others (1996). Most of the sandstone beds of the Scherr and Foreknobs Formations are 

interpreted as shallow-marine to shoreline, fluvial-deltaic, delta-front, and tidal-flat deposits (Slingerland and 

Loulé, 1988; Harper, 1999; Dennison, 2005), whereas 

the red beds are interpreted as subaerially exposed 

alluvial-plain, fluvial, and fluvial-deltaic deposits (Dennison and others, 1988; Harper, 1999). Sandstones in 

the Elk and Bradford plays are interpreted as prodeltaic-turbidite and distal-shelf deposits that formed in 

deeper water (Donaldson and others, 1996; Boswell, 

Thomas, and others, 1996), whereas sandstones of the 

Venango play are interpreted as marine-shoreline and 

wave-dominated delta deposits (Boswell, Heim, and 

others, 1996).

The Elk Group extends westward from drill hole 

9 for about 12 mi, where it changes facies into the 

upper part of the Brallier Formation. The approximate 

westward limit of the Elk Group, as interpreted on 

cross section C–C′, coincides reasonably well with a 

sandstone boundary on the percent siltstone and sandstone maps of Filer (2002, 2003). The Bradford Group 

extends beyond the Elk Group to a location about 13 

mi west of drill hole 8. Red beds that constitute the 

middle part of the Venango Group are present in drill 

holes 8 and 9 and extend to about 14 mi beyond drill 

hole 8. The entire Venango Group extends across much 

of southwestern Pennsylvania as a 400- to 600-ft-thick 

sandstone-dominated unit that changes facies into the 

upper part of the Chagrin Shale about 10 mi east of drill 

hole 7.
20 Geologic Cross Section C–C’ Through the Appalachian Basin

The Catskill Formation (which extends from 

several miles east of drill hole 9 to the Schellsburg 

dome) is overlain by the Rockwell Formation, a 400- to 

650-ft-thick argillaceous sandstone unit (Kammer and 

Bjerstedt, 1986; Bjerstedt and Kammer, 1988; Berg, 

1999). West of the arbitrary boundary near drill hole 

9, the Rockwell Formation is replaced (in ascending 

order) by the following sandstone and shale units: (1) 

the upper part of the Venango Group; (2) the Upper 

Devonian Oswayo Formation; (3) the informal Upper 

Devonian Murrysville zone of Harper and Laughrey 

(1987); (4) the Lower Mississippian Cuyahoga Group; 

and (5) the Lower Mississippian Shenango Formation, which includes the informal Squaw sandstone 

at the base (Harper and Laughrey, 1987; Berg, 1999). 

The Oswayo Formation continues to drill hole 8 and 

several miles beyond, where the formation changes 

facies to the Riceville Formation. The Murrysville zone 

of Harper and Laughrey (1987) continues farther west 

of drill hole 8 to about the Amity anticline, where it 

changes to the Berea and Cussewago Sandstones (undivided) of Harper and Laughrey (1987). West of drill 

hole 6, the Cussewago Sandstone continues into Ohio 

until just past drill hole 5, whereas the Berea Sandstone 

and the overlying Lower Mississippian Sunbury Shale 

(as recognized by Pepper and others, 1954; Pashin 

and Ettensohn, 1995; Tomastik, 1996) continue across 

eastern Ohio to the end of the cross section (drill holes 

1 and 2).

The unconformity shown on cross section C–C′

at the base of the Berea, Cussewago, and Murrysville 

zone of Harper and Laughrey (1987) is based largely 

on the interpretations of Kammer and Bjerstedt (1986), 

Bjerstedt and Kammer (1988), and Boswell and Jewell 

(1988) in northern West Virginia (see cross section 

D–D′) and south-central Pennsylvania. Although not 

recognized by Pashin and Ettensohn (1995) or Slucher 

(2004) in eastern Ohio, the unconformity at the base 

of the Berea Sandstone is interpreted in this report to 

extend a short distance into eastern Ohio to the vicinity 

of drill hole 5.

Most of the Berea Sandstone in cross section C–C′

is interpreted as fluvial-deltaic, shallow-marine, and 

barrier-island deposits derived from the north and east 

(Pepper and others, 1954; Tomastik, 1996). Sequencestratigraphic interpretations by Pashin and Ettensohn 

(1995) suggested that the Berea Sandstone is essentially a lowstand wedge consisting of sand-rich estuary 

deposits. The sub-Berea unconformity shown on cross 

section C–C′ may be related to a eustatic drop in sea 

level possibly associated with glaciation (Pashin and 

Ettensohn, 1995).

The Cuyahoga Group in southwestern Pennsylvania (drill holes 7–9) and northernmost West Virginia 

(drill hole 6) is overlain by the Shenango Formation 

(Harper and Laughrey, 1987); these two units have a 

combined thickness of 300 to 350 ft. The Cuyahoga 

Group correlates with the Cuyahoga Formation in drill 

hole 5, but the Shenango Formation is absent because 

of truncation. The Cuyahoga Formation extends across 

most of northeastern Ohio and crops out between drill 

holes 2 and 4. East of drill hole 9, the Murrysville zone, 

Cuyahoga Group, and Shenango Formation correlate 

with the upper half of the Rockwell Formation. In 

south-central Pennsylvania (between the Laurel Hill 

anticline near drill hole 9 and the Schellsburg dome 

near drill hole 10), the Rockwell Formation is overlain 

conformably by the 100- to 150-ft-thick Lower Mississippian Burgoon Sandstone (Kammer and Bjerstedt, 

1986; Berg, 1999; Brezinski, 1999). Furthermore, in 

southwestern Pennsylvania (near drill holes 7 and 8), 

the Shenango Formation (equivalent to the uppermost part of the Rockwell Formation) also is overlain 

conformably by the Burgoon Sandstone (Harper and 

Laughrey, 1987). The Burgoon Sandstone (which is 

known informally as the Big Injun sandstone) extends 

westward to several miles west of drill hole 6, where 

the sandstone is truncated by the Lower Pennsylvanian 

unconformity. This location of the truncated margin of 

the Burgoon Sandstone is consistent with the northeasttrending truncated margin of the Burgoon shown by 

Brezinski (1999). The Burgoon Sandstone is interpreted 

as a braided-fluvial deposit (Berg, 1999; Brezinski, 

1999).

Upper Mississippian Carbonate Strata

Upper Mississippian carbonate strata consist of 

(1) calcareous sandstone and sandy limestone of the 

Loyalhanna Formation and (2) fossiliferous limestone 

of the Greenbrier Formation and Wymps Gap Member 

of the Mauch Chunk Formation. The Upper Mississippian Loyalhanna Formation (fig. 2) rests unconformably (Loyalhanna unconformity) on the Lower Mississippian Burgoon Sandstone from the Schellsburg dome 

near drill hole 10 (de Witt, 1974), across the Laurel Hill 

anticline near drill hole 9 (Flint, 1965), to a pinchout 

near the Pennsylvania-West Virginia border between 

the No. 10 Matthews and No. 1 McMichael drill holes 

(Harper and Laughrey, 1987; also located on cross 

section C–C′). South of cross section C–C′, the Loyalhanna Formation merges with a 100-ft-thick quartzose 

sandstone that is informally named the “Greenbrier 

Big Injun sandstone” (Vargo and Matchen, 1996) at the 

base of the Upper Mississippian Greenbrier Formation. 

The Greenbrier Formation on cross section C–C′ is limited to a small area in and around the No. 1 Duvall drill 

hole (Harper and Laughrey, 1987; also located on cross 

section C–C′) about 23 mi west of drill hole 8. This 

locality represents the approximate northernmost extent 

of the Greenbrier Formation into southwestern Pennsylvania (Smosna, 1996). To the east, the top part of the 

Greenbrier Formation thins abruptly to a tongue and 

is replaced by the Wymps Gap Member of the Mauch 

Chunk Formation (fig. 2) in the Laurel Hill (drill hole 

9), Chestnut Ridge, and Negro Mountain anticlines 

(Hickok and Moyer, 1940; Flint, 1965; Stamm, 2004).

The sandstone-dominated Loyalhanna Formation, 

which is commonly characterized by units of mediumscale crossbedding, has been interpreted as an eolian 

deposit (Butts, 1924; Ahlbrandt, 1995; Wynn, 2003), 

as a marine or coastal sand flat deposit (Flint, 1965; 
Stratigraphic Framework 21

Adams, 1970; Carney and Smosna, 1989), or as a combination of eolian, sabkha, and wadi deposits (Krezoski 

and others, 2005). The Greenbrier Formation and the 

Wymps Gap Member are interpreted as predominantly 

shallow-water, open-marine deposits (Flint, 1965; Carney and Smosna, 1989; Brezinski, 1999).

Upper Mississippian, Pennsylvanian, and 

Permian Siliciclastic Strata

The Upper Mississippian, Pennsylvanian, and 

Permian siliciclastic strata on cross section C–C′

consist of sandstone, red and gray shale, limestone, and 

coal (fig. 2). The Upper Mississippian and Pennsylvanian siliciclastic strata are as thick as 1,550 ft, whereas 

the Permian siliciclastic strata are only as thick as 150 

ft (because they are deeply eroded). These Mississippian to Permian strata include the following units (in 

ascending order): the Mississippian Mauch Chunk Formation; the Pennsylvanian Pottsville Group, Allegheny 

Group, Conemaugh Group, and Monongahela Group; 

and the Pennsylvanian to Permian Dunkard Group 

(see figure 2 for all units except the Monongahela and 

Dunkard Groups).

The Upper Mississippian to Permian siliciclastic 

strata are interpreted as predominantly nonmarine sediments derived from an easterly source and deposited in 

a rapidly subsiding foreland basin. This foreland basin 

and its sedimentary deposits are associated with the 

Alleghanian orogeny (Colton, 1970; Milici and de Witt, 

1988; Hatcher and others, 1989; Faill, 1997b, 1998).

Along the Pennsylvania part of cross section C–C′, 

the Upper Mississippian Mauch Chunk Formation 

consists of a 50- to 400-ft-thick unit of gray and red 

shale, sandstone, and fossiliferous limestone (the previously discussed Wymps Gap Member) that conformably overlies the Loyalhanna Formation (Flint, 1965; 

de Witt, 1974; Harper and Laughrey, 1987). Westward, 

the Mauch Chunk Formation thins to a 30-ft-thick shale 

in northernmost West Virginia (drill hole 6), beyond 

which the formation is truncated by the overlying 

Pennsylvanian Pottsville Formation near the Ohio-West 

Virginia border.

The Lower and Middle Pennsylvanian Pottsville 

Group (which consists of sandstone; conglomeratic 

sandstone; sandy, gray shale; gray shale; and minor 

coal) unconformably overlies the Mauch Chunk Formation in Pennsylvania and the Cuyahoga Formation 

in Ohio. The widespread unconformity at the base of 

the Pottsville Group is known by various names that 

include the basal Pennsylvanian unconformity (Brezinski, 1999), the sub-Pennsylvanian unconformity 

(Beuthin, 1994), the Mississippian-Pennsylvanian 

unconformity (Rice and Schwietering, 1988), and the 

Lower Pennsylvanian unconformity (this report). The 

Pottsville Group is 150 to 200 ft thick on cross section 

C–C′ in Pennsylvania where it crops out along both 

flanks of the Chestnut Ridge anticline near drill hole 8 

and the Laurel Hill anticline near drill hole 9 (Hickok 

and Moyer, 1940; Flint, 1965) and along the western 

flank of the Schellsburg dome near drill hole 10. West 

of drill hole 8, the Pottsville Group extends through the 

subsurface of southwestern Pennsylvania (drill holes 6 

and 7) and part of northeastern Ohio (drill hole 5) and 

resurfaces in outcrops in northeastern Ohio near drill 

hole 4. The Pottsville Group may also crop out along 

the deeply incised valley of the Ohio River along the 

Ohio-West Virginia border. In northeastern Ohio, the 

Pottsville Group is difficult to identify as a separate unit 

(Slucher and Rice, 1994) where it is commonly mapped 

with the overlying Allegheny Group (for example, 

Slucher, 1996a; Slucher and Larsen, 1996a; Swinford 

and Shrake, 1996b). In northeastern Ohio, the Pottsville Group is tentatively recognized in drill hole 4 as a 

400-ft-thick unit of sandstone and shale. Between about 

4 mi west of drill hole 4 and about 8 mi west of drill 

hole 3, scattered and discontinuous units of conglomeratic sandstone are mapped as the Sharon Conglomerate 

of the Pottsville Group (Fuller, 1955). Pottsville Group 

strata are interpreted as being primarily fluvial in origin 

(Presley, 1979; Edmunds and others, 1979, 1999; Rice 

and Schwietering, 1988), but thin beds of shale and 

limestone with brackish-water and marine fauna have 

been reported in western Pennsylvania (Edmunds and 

others, 1979, 1999) and in northeastern Ohio (Slucher 

and Rice, 1994). 

The Middle Pennsylvanian Allegheny Group 

(which consists of gray shale, sandstone, coal, and 

local thin limestone) conformably overlies the Pottsville Group. Along cross section C–C′, the Allegheny 

Group extends more or less continuously as a 150- to 

350-ft-thick unit in Pennsylvania, except where the 

group has been eroded along the crest of the Laurel Hill 

anticline in drill hole 9 (Flint, 1965), along the crest of 

the Chestnut Ridge anticline in drill hole 8 (Hickok and 

Moyer, 1940), and on the western flank of the Schellsburg dome near drill hole 10. The Allegheny Group 

extends into northeastern Ohio (with approximately the 

same thickness) to a belt of scattered outcrops about 1 

to 4 mi east of drill hole 4. Prominent coal beds in the 

Allegheny Group (Lower and Middle Kittanning coal 

beds and Upper Freeport coal bed) have been identified along parts of the cross section in Pennsylvania 

(Hickok and Moyer, 1940; Flint, 1965; Wagner, Heyman, and others, 1975) and in Ohio (Larsen and Rea, 

1990; Slucher and Larsen, 1990). Strata of the Allegheny Group are interpreted as alluvial-plain, delta-plain, 

marginal-marine, and peat-swamp deposits (Edmunds 

and others, 1979, 1999).

Conformably overlying the Allegheny Group is 

the Upper Pennsylvanian Conemaugh Group (which 

consists of gray and red shale, sandstone, and coal). 

The Conemaugh Group forms a relatively continuous 

450- to 550-ft-thick unit that crosses western Pennsylvania from near drill hole 8 to about 12 mi east of 

drill hole 7. Between drill holes 8 and 10, incomplete 

sections of the Conemaugh Group are preserved in synclinal structures. West of drill hole 7, the Conemaugh 

Group occurs as discontinuous sections in scattered 

outcrops across northernmost West Virginia (drill hole 

6) and easternmost Ohio (drill hole 5) and extends as 

far west as 6 mi west of drill hole 5. The Conemaugh 
22 Geologic Cross Section C–C’ Through the Appalachian Basin

Group is overlain conformably by the Upper Pennsylvanian Monongahela Group, which is overlain in 

turn by the Upper Pennsylvanian to Lower Permian 

Dunkard Group. The Dunkard Group is the youngest 

Paleozoic strata preserved in the Appalachian basin 

(Berryhill and others, 1971; Harper and Laughrey, 

1987; Edmunds, 1999). Both the Monongahela and 

Dunkard Groups consist largely of gray to red shale, 

sandstone, limestone, and coal. Several limestone beds 

as much as 40 ft thick are reported in the Monongahela 

Group in a region on cross section C–C′ about midway 

between the No. 1 Duvall drill hole and the No. 10 

McDonald drill hole (Wagner, Craft, and others, 1975). 

The thickest and most widespread of the coal beds in 

the Monongahela to Dunkard interval is the Pittsburgh 

coal bed, which is located at the base of the Monongahela Group (Berryhill and Swanson, 1962). The 

Pittsburgh coal bed is as much as 9 to 10 ft thick in the 

Uniontown syncline (Hickok and Moyer, 1940; Tewalt 

and others, 1997) and thins to 1 to 2 ft near the outcrop 

limit of the Monongahela Group southeast of drill holes 

7 and 8 (Tewalt and others, 1997).

Donaldson (1974), Edmunds and others (1979, 

1999), and Edmunds (1999) interpreted the siliciclastic 

and carbonate strata in the Monongahela Group and 

Dunkard Group as alluvial-plain, delta-plain, lacustrine, 

and marginal-lacustrine deposits, whereas Cecil and 

others (1985) interpreted the coal beds as topogenous, 

planar-swamp deposits that accumulated under humid 

climate conditions.

Acknowledgments

We thank Ione L. Taylor (USGS) and James L. 

Coleman, Jr. (USGS), for recognizing the scientific 

value of this regional geologic cross section and for 

their keen interest and enthusiastic support during 

all stages of the investigation. Also, we thank Robert 

C. Milici (USGS) for his critical geological insights, 

discussions of Appalachian geology, and suggestions 

regarding cross-section methodology. Christopher P. 

Garrity (USGS) significantly improved the cross section by providing a digital topographic profile based on 

DEM data. Robert C. Milici, John A. Harper (Pennsylvania Bureau of Topographic and Geologic Survey), 

and James L. Coleman, Jr., improved the cross section 

and text through careful and thoughtful reviews.

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Appendix A.—Table Summarizing Drill Holes, Stratigraphic Units, and 

Depths of Stratigraphic Units in Cross Section C–C’
36 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number 1 2 3 4 5 

American Petroleum Institute 

number 34–043–20011 34–093–20794 34–103–21143 34–151–21081 34–029–20648 

Lease name No. 1 Krysik-Wakefield No. 1 A and A Born No. 1–A F.L. Smith Estate No. 1–381 B. Westfall No. 3 Frank Murray 

Permanent datum Ground level NA Ground level Ground level Ground level 

Ground level elevation (ft) 822.45 848 1,185.5 1,137.3 1,183.3 

Kelly bushing elevation (ft) 828.45 848 1,200 1,144.3 1,193 

Measured from KB (6 ft APD) GL KB (14.5 ft APD) KB (7 ft APD) KB (9.7 ft APD) 

Drill depth (ft) 4,463 4,591 7,040 7,961 10,242 

KB elevation - GL elevation (ft) 6.0 0.0 14.5 7.0 9.7 

Formation 1 Berea Sandstone Sunbury Shale

Sharon Conglomerate of 

Pottsville Group Pottsville Group Conemaugh Group 

System or series Upper Devonian Lower Mississippian Lower Pennsylvanian Lower Pennsylvanian Middle to Upper Pennsylvanian 

Formation top (relative to KB) (ft) -6 0 -14.5 -7 -9.7 

Formation top (relative to GL) (ft) 0 0 0 0 0 

Formation top (relative to SL) (ft) 822.45 848 1,185.5 1,137.3 1,193 

Formation 2 Bedford Shale Berea Sandstone Cuyahoga Formation Cuyahoga Formation Allegheny Group 

System or series Upper Devonian Upper Devonian Lower Mississippian Lower Mississippian Middle Pennsylvanian 

Formation top (relative to KB) (ft) -10 -40 -55 -340 -20 

Formation top (relative to GL) (ft) -4 -40 -40.5 -333 -10.3 

Formation top (relative to SL) (ft) 818.45 808 1,145 804.3 1,173 

Formation 3

Cleveland Member of 

Ohio Shale Bedford Shale Sunbury Shale Sunbury Shale Pottsville Group 

System or series Upper Devonian Upper Devonian Lower Mississippian Lower Mississippian Lower Pennsylvanian 

Formation top (relative to KB) (ft) -60 -100 -380 -635 -190 

Formation top (relative to GL) (ft) -54 -100 -365.5 -628 -180.3 

Formation top (relative to SL) (ft) 768.45 748 820 509.3 1,003 

Formation 4 Three Lick Bed of Ohio Shale

Cleveland Member of 

Ohio Shale Berea Sandstone Berea Sandstone

Cuyahoga Formation 

(upper part) 

System or series Upper Devonian Upper Devonian Upper Devonian Upper Devonian Lower Mississippian 

Formation top (relative to KB) (ft) -107 -150 -390 -657 -450 

Formation top (relative to GL) (ft) -101 -150 -375.5 -650 -440.3 

Formation top (relative to SL) (ft) 721.45 698 810 487.3 743 
Appendix A 37

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number

American Petroleum Institute 

number

Lease name

Permanent datum

Ground level elevation (ft)

Kelly bushing elevation (ft)

Measured from

Drill depth (ft)

KB elevation - GL elevation (ft)

6

47–029–00080

No. 1 S. Minesinger

Ground level

1,039

1,052

KB (13 ft APD)

10,387

13.0

7

37–007–20060

No. 1 Richard J. Ashcroft

Ground level

1,120

1,130

KB (10 ft APD)

7,590

10.0

8

37–051–20056

No. 1 E.C. Ricks

Ground level

2,523

2,539

KB (16 ft APD)

12,041

16.0

9

37–111–20045

No. 1 Leonard Svetz

Ground level

2,450

2,473

KB (23 ft APD)

21,460

23.0

10

37–009–20034

No. 1 Schellsburg

Ground level

1,650

1,663

KB (13 ft APD)

11,850

13.0

11

37–009–20060

No. 1 Fred Steele

Ground level

1,162

1,189

GL

15,500

27.0

Formation 1 Conemaugh Group Conemaugh Group

Burgoon Sandstone 

(Big Injun sandstone)

Mauch Chunk Formation 

(upper part) Shriver Formation Beekmantown Group

System or series

Middle to Upper 

Pennsylvanian

Middle to Upper 

Pennsylvanian Lower Mississippian Upper Mississippian Lower Devonian

Lower to Middle 

Ordovician

Formation top (relative to KB) (ft) -13 -10 -16 -23 -13 0

Formation top (relative to GL) (ft) 0 0 0 0 0 0

Formation top (relative to SL) (ft) 1,039 1,120 2,523 2,450 1,650 1,162

Formation 2 Allegheny Group Allegheny Group Shenango Formation

Wymps Gap Limestone 

Member Mandata Shale

Mines Dolomite Member 

of Gatesburg Formation

System or series Middle Pennsylvanian Middle Pennsylvanian Lower Mississippian Upper Mississippian Lower Devonian Upper Cambrian

Formation top (relative to KB) (ft) -25 -230 -130 -235 -50 -870

Formation top (relative to GL) (ft) -12 -220 -114 -212 -37 -870

Formation top (relative to SL) (ft) 1,027 900 2,409 2,238 1,613 292

Formation 3 Pottsville Group Pottsville Group

Shenango Formation 

(Squaw sandstone)

Mauch Chunk Formation 

(lower part)

Corriganville and New 

Creek Limestones 

(undivided)

Gatesburg Formation 

(upper sandy member)

System or series Lower Pennsylvanian Lower Pennsylvanian Lower Mississippian Middle Mississippian Lower Devonian Upper Cambrian

Formation top (relative to KB) (ft) -368 -565 -215 -310 -93 -1,065

Formation top (relative to GL) (ft) -355 -555 -199 -287 -80 -1,065

Formation top (relative to SL) (ft) 684 565 2,324 2,163 1,570 97

Formation 4 Mauch Chunk Formation Mauch Chunk Formation Cuyahoga Group Loyalhanna Formation Keyser Formation

Ore Hill Limestone 

Member of Gatesburg 

Formation

System or series

Middle to Upper 

Mississippian

Middle to Upper 

Mississippian Lower Mississippian Middle Mississippian

Upper Silurian to 

Lower Devonian Upper Cambrian

Formation top (relative to KB) (ft) -560 -720 -340 -365 -160 -2,400

Formation top (relative to GL) (ft) -547 -710 -324 -342 -147 -2,400

Formation top (relative to SL) (ft) 492 410 2,199 2,108 1,503 -1,238
38 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number 1 2 3 4 5 

American Petroleum Institute 

number 34–043–20011 34–093–20794 34–103–21143 34–151–21081 34–029–20648 

Lease name No. 1 Krysik-Wakefield No. 1 A and A Born No. 1–A F.L. Smith Estate No. 1–381 B. Westfall No. 3 Frank Murray 

Permanent datum Ground level NA Ground level Ground level Ground level 

Ground level elevation (ft) 822.45 848 1,185.5 1,137.3 1,183.3 

Kelly bushing elevation (ft) 828.45 848 1,200 1,144.3 1,193 

Measured from KB (6 ft APD) GL KB (14.5 ft APD) KB (7 ft APD) KB (9.7 ft APD) 

Drill depth (ft) 4,463 4,591 7,040 7,961 10,242 

KB elevation - GL elevation (ft) 6.0 0.0 14.5 7.0 9.7 

Formation 5 Huron Member of Ohio Shale Three Lick Bed of Ohio Shale Bedford Shale Bedford Shale

Cuyahoga Formation 

(unnamed sandstone) 

System or series Upper Devonian Upper Devonian Upper Devonian Upper Devonian Lower Mississippian 

Formation top (relative to KB) (ft) -255 -190 -440 -684 -498 

Formation top (relative to GL) (ft) -249 -190 -425.5 -677 -488.3 

Formation top (relative to SL) (ft) 573.45 658 760 460.3 695 

Formation 6 Olentangy Shale (upper part) Huron Member of Ohio Shale

Cleveland Member of 

Ohio Shale Chagrin Shale

Cuyahoga Formation 

(lower part) 

System or series Upper Devonian Upper Devonian Upper Devonian Upper Devonian Lower Mississippian 

Formation top (relative to KB) (ft) -518 -290 -513 -697 -540 

Formation top (relative to GL) (ft) -512 -290 -498.5 -690 -530.3 

Formation top (relative to SL) (ft) 310.45 558 687 447.3 653 

Formation 7

Prout Limestone and Plum 

Brook Shale (undivided) Olentangy Shale (upper part) Chagrin Shale Huron Member of Ohio Shale Sunbury Shale 

System or series Middle Devonian Upper Devonian Upper Devonian Upper Devonian Lower Mississippian 

Formation top (relative to KB) (ft) -553 -610 -536 -1,942 -712 

Formation top (relative to GL) (ft) -547 -610 -521.5 -1,935 -702.3 

Formation top (relative to SL) (ft) 275.45 238 664 -797.7 481 

Formation 8 Delaware Limestone

Prout Limestone and Plum 

Brook Shale (undivided) Huron Member of Ohio Shale Java Formation Berea Sandstone 

System or series Middle Devonian Middle Devonian Upper Devonian Upper Devonian Upper Devonian 

Formation top (relative to KB) (ft) -635 -650 -1,398 -2,380 -723 

Formation top (relative to GL) (ft) -629 -650 -1,383.5 -2,373 -713.3 

Formation top (relative to SL) (ft) 193.45 198 -198 -1,235.7 470 
Appendix A 39

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number

American Petroleum Institute 

number

Lease name

Permanent datum

Ground level elevation (ft)

Kelly bushing elevation (ft)

Measured from

Drill depth (ft)

KB elevation - GL elevation (ft)

6

47–029–00080

No. 1 S. Minesinger

Ground level

1,039

1,052

KB (13 ft APD)

10,387

13.0

7

37–007–20060

No. 1 Richard J. Ashcroft

Ground level

1,120

1,130

KB (10 ft APD)

7,590

10.0

8

37–051–20056

No. 1 E.C. Ricks

Ground level

2,523

2,539

KB (16 ft APD)

12,041

16.0

9

37–111–20045

No. 1 Leonard Svetz

Ground level

2,450

2,473

KB (23 ft APD)

21,460

23.0

10

37–009–20034

No. 1 Schellsburg

Ground level

1,650

1,663

KB (13 ft APD)

11,850

13.0

11

37–009–20060

No. 1 Fred Steele

Ground level

1,162

1,189

GL

15,500

27.0

Formation 5 Burgoon Sandstone

Burgoon Sandstone 

(Big Injun sandstone)

Murrysville zone of Harper 

and Laughrey (1987) Burgoon Sandstone Tonoloway Formation

Gatesburg Formation 

(lower sandy member)

System or series Lower Mississippian Lower Mississippian

Upper Devonian to 

Lower Mississippian Lower Mississippian Upper Silurian Upper Cambrian

Formation top (relative to KB) (ft) -592 -748 -500 -450 -410 -2,593

Formation top (relative to GL) (ft) -579 -738 -484 -427 -397 -2,593

Formation top (relative to SL) (ft) 460 382 2,039 2,023 1,253 -1,431

Formation 6

Shenango Formation 

(upper part) Shenango Formation Oswayo Formation Shenango Formation Wills Creek Formation

Warrior Formation 

(limestone member)

System or series Lower Mississippian Lower Mississippian Upper Devonian Lower Mississippian Upper Silurian

Middle and Upper 

Cambrian

Formation top (relative to KB) (ft) -636 -834 -605 -570 -1,038 -3,460

Formation top (relative to GL) (ft) -623 -824 -589 -547 -1,025 -3,460

Formation top (relative to SL) (ft) 416 296 1,934 1,903 625 -2,298

Formation 7

Shenango Formation 

(Squaw sandstone)

Shenango Formation 

(Squaw sandstone)

Venango Group 

(upper part) (sandy)

Shenango Formation 

(Squaw sandstone) Bloomsburg Formation

Warrior Formation 

(dolomite member)

System or series Lower Mississippian Lower Mississippian Upper Devonian Lower Mississippian Upper Silurian Middle Cambrian

Formation top (relative to KB) (ft) -692 -908 -670 -600 -1,430 -3,842

Formation top (relative to GL) (ft) -679 -898 -654 -577 -1,417 -3,842

Formation top (relative to SL) (ft) 360 222 1,869 1,873 233 -2,680

Formation 8

Cuyahoga Formation 

(upper part)

Cuyahoga Group 

(upper part)

Venango Group 

(middle part) (shale) Cuyahoga Group

McKenzie Member 

(upper part) of 

Mifflintown Formation Pleasant Hill Formation

System or series Lower Mississippian Lower Mississippian Upper Devonian Lower Mississippian Upper Silurian Middle Cambrian

Formation top (relative to KB) (ft) -722 -922 -807 -688 -1,460 -4,860

Formation top (relative to GL) (ft) -709 -912 -791 -665 -1,447 -4,860

Formation top (relative to SL) (ft) 330 208 1,732 1,785 203 -3,698
40 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number 1 2 3 4 5 

American Petroleum Institute 

number 34–043–20011 34–093–20794 34–103–21143 34–151–21081 34–029–20648 

Lease name No. 1 Krysik-Wakefield No. 1 A and A Born No. 1–A F.L. Smith Estate No. 1–381 B. Westfall No. 3 Frank Murray 

Permanent datum Ground level NA Ground level Ground level Ground level 

Ground level elevation (ft) 822.45 848 1,185.5 1,137.3 1,183.3 

Kelly bushing elevation (ft) 828.45 848 1,200 1,144.3 1,193 

Measured from KB (6 ft APD) GL KB (14.5 ft APD) KB (7 ft APD) KB (9.7 ft APD) 

Drill depth (ft) 4,463 4,591 7,040 7,961 10,242 

KB elevation - GL elevation (ft) 6.0 0.0 14.5 7.0 9.7 

Formation 9 Columbus Limestone Delaware Limestone Java Formation

Angola Shale Member of 

West Falls Formation Cussewago Sandstone 

System or series Middle Devonian Middle Devonian Upper Devonian Upper Devonian Upper Devonian 

Formation top (relative to KB) (ft) -668 -735 -1,650 -2,512 -765 

Formation top (relative to GL) (ft) -662 -735 -1,635.5 -2,505 -755.3 

Formation top (relative to SL) (ft) 160.45 113 -450 -1,367.7 428 

Formation 10 Detroit River Group Columbus Limestone

Angola Shale Member of 

West Falls Formation

Rhinestreet Shale Member of 

West Falls Formation

Chagrin Shale 

(upper part) (sandy shale) 

System or series Middle Devonian Middle Devonian Upper Devonian Upper Devonian Upper Devonian 

Formation top (relative to KB) (ft) -788 -765 -1,688 -2,590 -789 

Formation top (relative to GL) (ft) -782 -765 -1,673.5 -2,583 -779.3 

Formation top (relative to SL) (ft) 40.45 83 -488 -1,445.7 404 

Formation 11 Bois Blanc Formation(?) Detroit River Group

Rhinestreet Shale Member of 

West Falls Formation

Mahantango Formation of 

Hamilton Group

Chagrin Shale 

(middle part) (silty shale) 

System or series Lower Devonian Middle Devonian Upper Devonian Middle Devonian Upper Devonian 

Formation top (relative to KB) (ft) -850 -890 -1,748 -2,700 -1,305 

Formation top (relative to GL) (ft) -844 -890 -1,733.5 -2,693 -1,295.3 

Formation top (relative to SL) (ft) -21.55 -42 -548 -1,555.7 -112 

Formation 12 Bass Islands Dolomite Bois Blanc Formation(?)

Mahantango Formation of 

Hamilton Group

Marcellus Shale of 

Hamilton Group

Chagrin Shale 

(lower part) (shale) 

System or series Upper Silurian Lower Devonian Middle Devonian Middle Devonian Upper Devonian 

Formation top (relative to KB) (ft) -910 -955 -1,785 -2,820 -2,507 

Formation top (relative to GL) (ft) -904 -955 -1,770.5 -2,813 -2,497.3 

Formation top (relative to SL) (ft) -81.55 -107 -585 -1,675.7 -1,314 
Appendix A 41

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number

American Petroleum Institute 

number

Lease name

Permanent datum

Ground level elevation (ft)

Kelly bushing elevation (ft)

Measured from

Drill depth (ft)

KB elevation - GL elevation (ft)

6

47–029–00080

No. 1 S. Minesinger

Ground level

1,039

1,052

KB (13 ft APD)

10,387

13.0

7

37–007–20060

No. 1 Richard J. Ashcroft

Ground level

1,120

1,130

KB (10 ft APD)

7,590

10.0

8

37–051–20056

No. 1 E.C. Ricks

Ground level

2,523

2,539

KB (16 ft APD)

12,041

16.0

9

37–111–20045

No. 1 Leonard Svetz

Ground level

2,450

2,473

KB (23 ft APD)

21,460

23.0

10

37–009–20034

No. 1 Schellsburg

Ground level

1,650

1,663

KB (13 ft APD)

11,850

13.0

11

37–009–20060

No. 1 Fred Steele

Ground level

1,162

1,189

GL

15,500

27.0

Formation 9

Cuyahoga Formation 

(unnamed sandstone)

Cuyahoga Group 

(unnamed sandstone)

Venango Group 

(lower part) (sandy)

Murrysville zone of Harper 

and Laughrey (1987)

Rabble Run Member of 

Bloomsburg Formation

Waynesboro Formation 

(sandstone member)

System or series Lower Mississippian Lower Mississippian Upper Devonian

Upper Devonian to 

Lower Mississippian Upper Silurian Lower to Middle Cambrian

Formation top (relative to KB) (ft) -810 -1,060 -1,158 -803 -1,575 -5,355

Formation top (relative to GL) (ft) -797 -1,050 -1,142 -780 -1,562 -5,355

Formation top (relative to SL) (ft) 242 70 1,381 1,670 88 -4,193

Formation 10

Cuyahoga Formation 

(lower part)

Cuyahoga Group 

(lower part) Chadakoin Formation Oswayo Formation

McKenzie Member 

(lower part) of 

Mifflintown Formation Waynesboro Formation

System or series Lower Mississippian Lower Mississippian Upper Devonian Upper Devonian Lower Silurian Lower to Middle Cambrian

Formation top (relative to KB) (ft) -860 -1,082 -1,387 -865 -1,590 -5,500

Formation top (relative to GL) (ft) -847 -1,072 -1,371 -842 -1,577 -5,500

Formation top (relative to SL) (ft) 192 48 1,152 1,608 73 -4,338

Formation 11

Sunbury Shale equivalent 

of Harper and Laughrey 

(1987)

Sunbury Shale equivalent 

of Harper and Laughrey 

(1987) Bradford Group

Venango Group 

(upper part) (sandy)

Keefer Formation and 

Rochester Member of 

Mifflintown Formation 

(undivided)

Pleasant Hill Formation 

(top of zone of imbricate 

thrust faults)

System or series Lower Mississippian Lower Mississippian Upper Devonian Upper Devonian Lower Silurian Middle Cambrian

Formation top (relative to KB) (ft) -888 -1,146 -1,830 -1,000 -1,848 -5,617

Formation top (relative to GL) (ft) -875 -1,136 -1,814 -977 -1,835 -5,617

Formation top (relative to SL) (ft) 164 -16 709 1,473 -185 -4,455

Formation 12

Berea and Cussewago 

Sandstones (undivided) 

as used by Harper and 

Laughrey (1987)

Berea and Cussewago 

Sandstones (undivided) 

as used by Harper and 

Laughrey (1987) Brallier Formation

Venango Group 

(middle part) (shale)

Rose Hill Formation 

(upper part)

Pleasant Hill Formation 

(thrust fault at top)

System or series Upper Devonian Upper Devonian Upper Devonian Upper Devonian Lower Silurian Middle Cambrian

Formation top (relative to KB) (ft) -912 -1,172 -2,560 -1,228 -1,920 -6,100

Formation top (relative to GL) (ft) -899 -1,162 -2,544 -1,205 -1,907 -6,100

Formation top (relative to SL) (ft) 140 -42 -21 1,245 -257 -4,938
42 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number 1 2 3 4 5 

American Petroleum Institute 

number 34–043–20011 34–093–20794 34–103–21143 34–151–21081 34–029–20648 

Lease name No. 1 Krysik-Wakefield No. 1 A and A Born No. 1–A F.L. Smith Estate No. 1–381 B. Westfall No. 3 Frank Murray 

Permanent datum Ground level NA Ground level Ground level Ground level 

Ground level elevation (ft) 822.45 848 1,185.5 1,137.3 1,183.3 

Kelly bushing elevation (ft) 828.45 848 1,200 1,144.3 1,193 

Measured from KB (6 ft APD) GL KB (14.5 ft APD) KB (7 ft APD) KB (9.7 ft APD) 

Drill depth (ft) 4,463 4,591 7,040 7,961 10,242 

KB elevation - GL elevation (ft) 6.0 0.0 14.5 7.0 9.7 

Formation 13 Salina Group Bass Islands Dolomite

Marcellus Shale of 

Hamilton Group Onondaga Limestone

Dunkirk Shale Member of 

Perrysburg Formation 

System or series Upper Silurian Upper Silurian Middle Devonian Middle Devonian Upper Devonian 

Formation top (relative to KB) (ft) -970 -1,005 -1,892 -2,830 -2,880 

Formation top (relative to GL) (ft) -964 -1,005 -1,877.5 -2,823 -2,870.3 

Formation top (relative to SL) (ft) -141.55 -157 -692 -1,685.7 -1,687 

Formation 14 Lockport Dolomite Salina Group Onondaga Limestone Oriskany Sandstone Java Formation 

System or series Lower to Upper Silurian Upper Silurian Middle Devonian Lower Devonian Upper Devonian 

Formation top (relative to KB) (ft) -1,590 -1,087 -1,900 -3,100 -2,900 

Formation top (relative to GL) (ft) -1,584 -1,087 -1,885.5 -3,093 -2,890.3 

Formation top (relative to SL) (ft) -761.55 -239 -700 -1,955.7 -1,707 

Formation 15 Rochester Shale Lockport Dolomite Oriskany Sandstone Helderberg Limestone

Angola Shale Member of 

West Falls Formation 

System or series Lower Silurian Lower to Upper Silurian Lower Devonian Lower Devonian Upper Devonian 

Formation top (relative to KB) (ft) -1,780 -1,700 -2,180 -3,120 -3,070 

Formation top (relative to GL) (ft) -1,774 -1,700 -2,165.5 -3,113 -3,060.3 

Formation top (relative to SL) (ft) -951.55 -852 -980 -1,975.7 -1,877 

Formation 16

Lower Silurian carbonates and 

shales (undivided) Rochester Shale Helderberg Limestone Bass Islands Dolomite

Rhinestreet Shale Member of 

West Falls Formation 

System or series Lower Silurian Lower Silurian Lower Devonian Upper Silurian Upper Devonian 

Formation top (relative to KB) (ft) -1,800 -1,880 -2,200 -3,278 -3,332 

Formation top (relative to GL) (ft) -1,794 -1,880 -2,185.5 -3,271 -3,322.3 

Formation top (relative to SL) (ft) -971.55 -1,032 -1,000 -2,133.7 -2,139 
Appendix A 43

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number

American Petroleum Institute 

number

Lease name

Permanent datum

Ground level elevation (ft)

Kelly bushing elevation (ft)

Measured from

Drill depth (ft)

KB elevation - GL elevation (ft)

6

47–029–00080

No. 1 S. Minesinger

Ground level

1,039

1,052

KB (13 ft APD)

10,387

13.0

7

37–007–20060

No. 1 Richard J. Ashcroft

Ground level

1,120

1,130

KB (10 ft APD)

7,590

10.0

8

37–051–20056

No. 1 E.C. Ricks

Ground level

2,523

2,539

KB (16 ft APD)

12,041

16.0

9

37–111–20045

No. 1 Leonard Svetz

Ground level

2,450

2,473

KB (23 ft APD)

21,460

23.0

10

37–009–20034

No. 1 Schellsburg

Ground level

1,650

1,663

KB (13 ft APD)

11,850

13.0

11

37–009–20060

No. 1 Fred Steele

Ground level

1,162

1,189

GL

15,500

27.0

Formation 13

Chagrin Shale 

(upper part) (sandy shale)

Chagrin Shale 

(upper part) (sandy shale) Sonyea Formation

Venango Group 

(lower part) (sandy)

Rose Hill Formation 

(sandstone)

Waynesboro Formation 

(sandstone member)

System or series Upper Devonian Upper Devonian Upper Devonian Upper Devonian Lower Silurian Lower to Middle Cambrian

Formation top (relative to KB) (ft) -972 -1,244 -6,580 -1,490 -2,480 -6,510

Formation top (relative to GL) (ft) -959 -1,234 -6,564 -1,467 -2,467 -6,510

Formation top (relative to SL) (ft) 80 -114 -4,041 983 -817 -5,348

Formation 14

Chagrin Shale 

(middle part) (silty shale)

Chagrin Shale 

(middle part) (silty shale) Genesee Formation Chadakoin Formation

Rose Hill Formation 

(lower part)

Pleasant Hill Formation 

(thrust fault at top)

System or series Upper Devonian Upper Devonian Upper Devonian Upper Devonian Lower Silurian Middle Cambrian

Formation top (relative to KB) (ft) -1,535 -1,796 -7,018 -1,852 -2,532 -6,700

Formation top (relative to GL) (ft) -1,522 -1,786 -7,002 -1,829 -2,519 -6,700

Formation top (relative to SL) (ft) -483 -666 -4,479 621 -869 -5,538

Formation 15

Chagrin Shale 

(lower part) (shale)

Chagrin Shale 

(lower part) (shale) Tully Limestone Bradford Group

Castanea Member of 

Tuscarora Formation

Beekmantown Group 

(lower anhydritic 

dolomite?) 

(thrust fault at top)

System or series Upper Devonian Upper Devonian Middle Devonian Upper Devonian Lower Silurian Lower Ordovician

Formation top (relative to KB) (ft) -2,583 -2,935 -7,240 -1,950 -2,680 -7,327

Formation top (relative to GL) (ft) -2,570 -2,925 -7,224 -1,927 -2,667 -7,327

Formation top (relative to SL) (ft) -1,531 -1,805 -4,701 523 -1,017 -6,165

Formation 16

Dunkirk Shale Member of 

Perrysburg Formation

Dunkirk Shale Member of 

Perrysburg Formation

Mahantango Formation of 

Hamilton Group Elk Group Tuscarora Formation

Beekmantown Group 

(dolomite in lower part)

System or series Upper Devonian Upper Devonian Middle Devonian Upper Devonian Lower Silurian Lower Ordovician

Formation top (relative to KB) (ft) -3,390 -3,724 -7,345 -3,200 -2,728 -8,050

Formation top (relative to GL) (ft) -3,377 -3,714 -7,329 -3,177 -2,715 -8,050

Formation top (relative to SL) (ft) -2,338 -2,594 -4,806 -727 -1,065 -6,888
44 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number 1 2 3 4 5 

American Petroleum Institute 

number 34–043–20011 34–093–20794 34–103–21143 34–151–21081 34–029–20648 

Lease name No. 1 Krysik-Wakefield No. 1 A and A Born No. 1–A F.L. Smith Estate No. 1–381 B. Westfall No. 3 Frank Murray 

Permanent datum Ground level NA Ground level Ground level Ground level 

Ground level elevation (ft) 822.45 848 1,185.5 1,137.3 1,183.3 

Kelly bushing elevation (ft) 828.45 848 1,200 1,144.3 1,193 

Measured from KB (6 ft APD) GL KB (14.5 ft APD) KB (7 ft APD) KB (9.7 ft APD) 

Drill depth (ft) 4,463 4,591 7,040 7,961 10,242 

KB elevation - GL elevation (ft) 6.0 0.0 14.5 7.0 9.7 

Formation 17 Cabot Head Shale

Lower Silurian carbonates and 

shales (undivided) Bass Islands Dolomite Salina Group (upper part) Sonyea Formation 

System or series Lower Silurian Lower Silurian Upper Silurian Upper Silurian Upper Devonian 

Formation top (relative to KB) (ft) -1,830 -1,900 -2,265 -3,305 -3,470 

Formation top (relative to GL) (ft) -1,824 -1,900 -2,250.5 -3,298 -3,460.3 

Formation top (relative to SL) (ft) -1,001.55 -1,052 -1,065 -2,160.7 -2,277 

Formation 18 Brassfield Limestone Cabot Head Shale Salina Group (upper part) Salina Group (halite zone)

Mahantango Formation of 

Hamilton Group 

System or series Lower Silurian Lower Silurian Upper Silurian Upper Silurian Middle Devonian 

Formation top (relative to KB) (ft) -1,908 -1,925 -2,309 -3,503 -3,530 

Formation top (relative to GL) (ft) -1,902 -1,925 -2,294.5 -3,496 -3,520.3 

Formation top (relative to SL) (ft) -1,079.55 -1,077 -1,109 -2,358.7 -2,337 

Formation 19 Queenston Shale Brassfield Limestone Salina Group (halite zone?) Salina Group (lower part)

Marcellus Shale of 

Hamilton Group 

System or series Upper Ordovician Lower Silurian Upper Silurian Upper Silurian Middle Devonian 

Formation top (relative to KB) (ft) -1,968 -2,012 -2,630 -3,900 -3,690 

Formation top (relative to GL) (ft) -1,962 -2,012 -2,615.5 -3,893 -3,680.3 

Formation top (relative to SL) (ft) -1,139.55 -1,164 -1,430 -2,755.7 -2,497 

Formation 20 Cincinnati group Queenston Shale Salina Group (lower part) Lockport Dolomite Onondaga Limestone 

System or series Upper Ordovician Upper Ordovician Upper Silurian Lower to Upper Silurian Middle Devonian 

Formation top (relative to KB) (ft) -2,211 -2,070 -2,760 -4,163 -3,708 

Formation top (relative to GL) (ft) -2,205 -2,070 -2,745.5 -4,156 -3,698.3 

Formation top (relative to SL) (ft) -1,382.55 -1,222 -1,560 -3,018.7 -2,515 
Appendix A 45

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number

American Petroleum Institute 

number

Lease name

Permanent datum

Ground level elevation (ft)

Kelly bushing elevation (ft)

Measured from

Drill depth (ft)

KB elevation - GL elevation (ft)

6

47–029–00080

No. 1 S. Minesinger

Ground level

1,039

1,052

KB (13 ft APD)

10,387

13.0

7

37–007–20060

No. 1 Richard J. Ashcroft

Ground level

1,120

1,130

KB (10 ft APD)

7,590

10.0

8

37–051–20056

No. 1 E.C. Ricks

Ground level

2,523

2,539

KB (16 ft APD)

12,041

16.0

9

37–111–20045

No. 1 Leonard Svetz

Ground level

2,450

2,473

KB (23 ft APD)

21,460

23.0

10

37–009–20034

No. 1 Schellsburg

Ground level

1,650

1,663

KB (13 ft APD)

11,850

13.0

11

37–009–20060

No. 1 Fred Steele

Ground level

1,162

1,189

GL

15,500

27.0

Formation 17 Java Formation Java Formation

Marcellus Formation of 

Hamilton Group Brallier Formation

Rose Hill Formation 

(upper part) (fault at top)

Mines Dolomite Member 

of Gatesburg Formation

System or series Upper Devonian Upper Devonian Middle Devonian Upper Devonian Lower Silurian Upper Cambrian

Formation top (relative to KB) (ft) -3,420 -3,746 -7,620 -4,310 -2,810 -10,360

Formation top (relative to GL) (ft) -3,407 -3,736 -7,604 -4,287 -2,797 -10,360

Formation top (relative to SL) (ft) -2,368 -2,616 -5,081 -1,837 -1,147 -9,198

Formation 18

Angola Shale Member of 

West Falls Formation

Angola Shale Member of 

West Falls Formation Onondaga Formation

Harrell Formation (Sonyea 

Formation equivalent)

Rose Hill Formation 

(sandstone)

Gatesburg Formation 

(upper sandy member)

System or series Upper Devonian Upper Devonian Middle Devonian Upper Devonian Lower Silurian Upper Cambrian

Formation top (relative to KB) (ft) -3,595 -3,945 -7,780 -6,970 -2,996 -10,610

Formation top (relative to GL) (ft) -3,582 -3,935 -7,764 -6,947 -2,983 -10,610

Formation top (relative to SL) (ft) -2,543 -2,815 -5,241 -4,497 -1,333 -9,448

Formation 19

Rhinestreet Shale Member 

of West Falls Formation

Rhinestreet Shale Member 

of West Falls Formation Huntersville Chert

Harrell Formation 

(Genesee Formation 

equivalent)

Rose Hill Formation 

(lower part)

Ore Hill Limestone 

Member of Gatesburg 

Formation

System or series Upper Devonian Upper Devonian Middle Devonian Upper Devonian Lower Silurian Upper Cambrian

Formation top (relative to KB) (ft) -3,966 -4,435 -7,795 -7,490 -3,050 -11,300

Formation top (relative to GL) (ft) -3,953 -4,425 -7,779 -7,467 -3,037 -11,300

Formation top (relative to SL) (ft) -2,914 -3,305 -5,256 -5,017 -1,387 -10,138

Formation 20 Sonyea Formation Sonyea Formation Needmore Shale Tully Limestone

Castanea Member of 

Tuscarora Formation

Gatesburg Formation 

(lower sandy member)

System or series Upper Devonian Upper Devonian Middle Devonian Middle Devonian Lower Silurian Upper Cambrian

Formation top (relative to KB) (ft) -4,262 -4,680 -7,905 -7,668 -3,140 -11,400

Formation top (relative to GL) (ft) -4,249 -4,670 -7,889 -7,645 -3,127 -11,400

Formation top (relative to SL) (ft) -3,210 -3,550 -5,366 -5,195 -1,477 -10,238
46 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number 1 2 3 4 5 

American Petroleum Institute 

number 34–043–20011 34–093–20794 34–103–21143 34–151–21081 34–029–20648 

Lease name No. 1 Krysik-Wakefield No. 1 A and A Born No. 1–A F.L. Smith Estate No. 1–381 B. Westfall No. 3 Frank Murray 

Permanent datum Ground level NA Ground level Ground level Ground level 

Ground level elevation (ft) 822.45 848 1,185.5 1,137.3 1,183.3 

Kelly bushing elevation (ft) 828.45 848 1,200 1,144.3 1,193 

Measured from KB (6 ft APD) GL KB (14.5 ft APD) KB (7 ft APD) KB (9.7 ft APD) 

Drill depth (ft) 4,463 4,591 7,040 7,961 10,242 

KB elevation - GL elevation (ft) 6.0 0.0 14.5 7.0 9.7 

Formation 21 Utica Shale Cincinnati group Lockport Dolomite Rochester Shale Oriskany Sandstone 

System or series Upper Ordovician Upper Ordovician Lower to Upper Silurian Lower Silurian Lower Devonian 

Formation top (relative to KB) (ft) -2,820 -2,308 -3,148 -4,433 -4,000 

Formation top (relative to GL) (ft) -2,814 -2,308 -3,133.5 -4,426 -3,990.3 

Formation top (relative to SL) (ft) -1,991.55 -1,460 -1,948 -3,288.7 -2,807 

Formation 22 Trenton Limestone Utica Shale Rochester Shale

Lower Silurian carbonates and 

shales (undivided) Helderberg Limestone 

System or series Upper Ordovician Upper Ordovician Lower Silurian Lower Silurian Lower Devonian 

Formation top (relative to KB) (ft) -3,192 -2,988 -3,315 -4,580 -4,045 

Formation top (relative to GL) (ft) -3,186 -2,988 -3,300.5 -4,573 -4,035.3 

Formation top (relative to SL) (ft) -2,363.55 -2,140 -2,115 -3,435.7 -2,852 

Formation 23

Black River Group 

(Millbrig Bentonite Bed at top) Trenton Limestone

Lower Silurian carbonates and 

shales (undivided)

“Clinton” sandstone, Cabot Head 

Shale, and Medina sandstone 

(undivided) Bass Islands Dolomite 

System or series Upper Ordovician Upper Ordovician Lower Silurian Lower Silurian Upper Silurian 

Formation top (relative to KB) (ft) -3,270 -3,310 -3,383 -4,625 -4,255 

Formation top (relative to GL) (ft) -3,264 -3,310 -3,368.5 -4,618 -4,245.3 

Formation top (relative to SL) (ft) -2,441.55 -2,462 -2,183 -3,480.7 -3,062 

Formation 24 Deicke Bentonite Bed

Black River Group 

(Millbrig Bentonite Bed at top)

“Clinton” sandstone, Cabot Head 

Shale, and Medina sandstone 

(undivided) Queenston Shale Salina Group (upper part) 

System or series Upper Ordovician Upper Ordovician Lower Silurian Upper Ordovician Upper Silurian 

Formation top (relative to KB) (ft) -3,297 -3,395 -3,400 -4,810 -4,273 

Formation top (relative to GL) (ft) -3,291 -3,395 -3,385.5 -4,803 -4,263.3 

Formation top (relative to SL) (ft) -2,468.55 -2,547 -2,200 -3,665.7 -3,080 
Appendix A 47

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number

American Petroleum Institute 

number

Lease name

Permanent datum

Ground level elevation (ft)

Kelly bushing elevation (ft)

Measured from

Drill depth (ft)

KB elevation - GL elevation (ft)

6

47–029–00080

No. 1 S. Minesinger

Ground level

1,039

1,052

KB (13 ft APD)

10,387

13.0

7

37–007–20060

No. 1 Richard J. Ashcroft

Ground level

1,120

1,130

KB (10 ft APD)

7,590

10.0

8

37–051–20056

No. 1 E.C. Ricks

Ground level

2,523

2,539

KB (16 ft APD)

12,041

16.0

9

37–111–20045

No. 1 Leonard Svetz

Ground level

2,450

2,473

KB (23 ft APD)

21,460

23.0

10

37–009–20034

No. 1 Schellsburg

Ground level

1,650

1,663

KB (13 ft APD)

11,850

13.0

11

37–009–20060

No. 1 Fred Steele

Ground level

1,162

1,189

GL

15,500

27.0

Formation 21 Genesee Formation Genesee Formation Ridgeley Sandstone

Mahantango Formation of 

Hamilton Group Tuscarora Formation

Beekmantown Group 

(dolomite in lower part?) 

(thrust fault at top)

System or series Upper Devonian Upper Devonian Lower Devonian Middle Devonian Lower Silurian Lower Ordovician

Formation top (relative to KB) (ft) -4,317 -4,745 -7,929 -7,685 -3,200 -12,775

Formation top (relative to GL) (ft) -4,304 -4,735 -7,913 -7,662 -3,187 -12,775

Formation top (relative to SL) (ft) -3,265 -3,615 -5,390 -5,212 -1,537 -11,613

Formation 22 Tully Limestone Tully Limestone Licking Creek Limestone

Marcellus Formation of 

Hamilton Group

Tuscarora 

Formation-Juniata 

Formation transition zone

Mines Dolomite Member 

of Gatesburg Formation

System or series Middle Devonian Middle Devonian Lower Devonian Middle Devonian Upper Ordovician(?) Upper Cambrian

Formation top (relative to KB) (ft) -4,376 -4,816 -8,023 -8,263 -3,540 -13,920

Formation top (relative to GL) (ft) -4,363 -4,806 -8,007 -8,240 -3,527 -13,920

Formation top (relative to SL) (ft) -3,324 -3,686 -5,484 -5,790 -1,877 -12,758

Formation 23

Mahantango Formation of 

Hamilton Group

Mahantango Formation of 

Hamilton Group Mandata Shale Onondaga Formation Juniata Formation

Gatesburg Formation 

(upper sandy member)

System or series Middle Devonian Middle Devonian Lower Devonian Middle Devonian Upper Ordovician Upper Cambrian

Formation top (relative to KB) (ft) -4,380 -4,870 -8,252 -8,340 -3,620 -14,238

Formation top (relative to GL) (ft) -4,367 -4,860 -8,236 -8,317 -3,607 -14,238

Formation top (relative to SL) (ft) -3,328 -3,740 -5,713 -5,867 -1,957 -13,076

Formation 24

Marcellus Shale of 

Hamilton Group

Marcellus Formation of 

Hamilton Group

Corriganville and 

New Creek Limestones 

(undivided) Huntersville Chert Bald Eagle Formation

Ore Hill Limestone 

Member of Gatesburg 

Formation

System or series Middle Devonian Middle Devonian Lower Devonian Middle Devonian Upper Ordovician Upper Cambrian

Formation top (relative to KB) (ft) -4,572 -4,980 -8,272 -8,360 -4,885 -15,000

Formation top (relative to GL) (ft) -4,559 -4,970 -8,256 -8,337 -4,872 -15,000

Formation top (relative to SL) (ft) -3,520 -3,850 -5,733 -5,887 -3,222 -13,838
48 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number 1 2 3 4 5 

American Petroleum Institute 

number 34–043–20011 34–093–20794 34–103–21143 34–151–21081 34–029–20648 

Lease name No. 1 Krysik-Wakefield No. 1 A and A Born No. 1–A F.L. Smith Estate No. 1–381 B. Westfall No. 3 Frank Murray 

Permanent datum Ground level NA Ground level Ground level Ground level 

Ground level elevation (ft) 822.45 848 1,185.5 1,137.3 1,183.3 

Kelly bushing elevation (ft) 828.45 848 1,200 1,144.3 1,193 

Measured from KB (6 ft APD) GL KB (14.5 ft APD) KB (7 ft APD) KB (9.7 ft APD) 

Drill depth (ft) 4,463 4,591 7,040 7,961 10,242 

KB elevation - GL elevation (ft) 6.0 0.0 14.5 7.0 9.7 

Formation 25 Wells Creek formation Deicke Bentonite Bed Queenston Shale Cincinnati group Salina Group (halite zone) 

System or series Middle Ordovician Upper Ordovician Upper Ordovician Upper Ordovician Upper Silurian 

Formation top (relative to KB) (ft) -3,815 -3,412 -3,592 -5,300 -4,462 

Formation top (relative to GL) (ft) -3,809 -3,412 -3,577.5 -5,293 -4,452.3 

Formation top (relative to SL) (ft) -2,986.55 -2,564 -2,392 -4,155.7 -3,269 

Formation 26

Knox Dolomite 

(Copper Ridge dolomite 

(B zone and Krysik sandstone)) Wells Creek formation Cincinnati group Utica Shale Salina Group (lower part) 

System or series Upper Cambrian Middle Ordovician Upper Ordovician Upper Ordovician Upper Silurian 

Formation top (relative to KB) (ft) -3,850 -3,937 -3,960 -6,130 -5,030 

Formation top (relative to GL) (ft) -3,844 -3,937 -3,945.5 -6,123 -5,020.3 

Formation top (relative to SL) (ft) -3,021.55 -3,089 -2,760 -4,985.7 -3,837 

Formation 27

Knox Dolomite 

(Copper Ridge dolomite 

(lower part))

Knox Dolomite 

(Copper Ridge dolomite 

(B zone and Krysik sandstone)) Utica Shale Trenton Limestone Lockport Dolomite 

System or series Upper Cambrian Upper Cambrian Upper Ordovician Upper Ordovician Lower to Upper Silurian 

Formation top (relative to KB) (ft) -3,920 -4,000 -4,750 -6,430 -5,280 

Formation top (relative to GL) (ft) -3,914 -4,000 -4,735.5 -6,423 -5,270.3 

Formation top (relative to SL) (ft) -3,091.55 -3,152 -3,550 -5,285.7 -4,087 

Formation 28 Kerbel Formation

Knox Dolomite 

(Copper Ridge dolomite 

(lower part)) Trenton Limestone

Black River Group 

(Millbrig Bentonite Bed at top) Rochester Shale 

System or series Upper Cambrian Upper Cambrian Upper Ordovician Upper Ordovician Lower Silurian 

Formation top (relative to KB) (ft) -3,994 -4,035 -5,060 -6,533 -5,615 

Formation top (relative to GL) (ft) -3,988 -4,035 -5,045.5 -6,526 -5,605.3 

Formation top (relative to SL) (ft) -3,165.55 -3,187 -3,860 -5,388.7 -4,422 
Appendix A 49

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number

American Petroleum Institute 

number

Lease name

Permanent datum

Ground level elevation (ft)

Kelly bushing elevation (ft)

Measured from

Drill depth (ft)

KB elevation - GL elevation (ft)

6

47–029–00080

No. 1 S. Minesinger

Ground level

1,039

1,052

KB (13 ft APD)

10,387

13.0

7

37–007–20060

No. 1 Richard J. Ashcroft

Ground level

1,120

1,130

KB (10 ft APD)

7,590

10.0

8

37–051–20056

No. 1 E.C. Ricks

Ground level

2,523

2,539

KB (16 ft APD)

12,041

16.0

9

37–111–20045

No. 1 Leonard Svetz

Ground level

2,450

2,473

KB (23 ft APD)

21,460

23.0

10

37–009–20034

No. 1 Schellsburg

Ground level

1,650

1,663

KB (13 ft APD)

11,850

13.0

11

37–009–20060

No. 1 Fred Steele

Ground level

1,162

1,189

GL

15,500

27.0

Formation 25 Onondaga Limestone Onondaga Formation Keyser Formation Needmore Shale Reedsville Shale

Gatesburg Formation 

(lower sandy member)

System or series Middle Devonian Middle Devonian

Upper Silurian to 

Lower Devonian Middle Devonian Upper Ordovician Upper Cambrian

Formation top (relative to KB) (ft) -4,661 -5,056 -8,340 -8,480 -5,520 -15,178

Formation top (relative to GL) (ft) -4,648 -5,046 -8,324 -8,457 -5,507 -15,178

Formation top (relative to SL) (ft) -3,609 -3,926 -5,801 -6,007 -3,857 -14,016

Formation 26 Huntersville Chert Huntersville Chert Salina Group (upper part) Ridgeley Sandstone Antes Shale

System or series Middle Devonian Middle Devonian Upper Silurian Lower Devonian Upper Ordovician

Formation top (relative to KB) (ft) -4,700 -5,090 -8,600 -8,500 -7,270

Formation top (relative to GL) (ft) -4,687 -5,080 -8,584 -8,477 -7,257

Formation top (relative to SL) (ft) -3,648 -3,960 -6061 -6,027 -5,607

Formation 27 Needmore Shale Needmore Shale Salina Group (halite zone) Licking Creek Limestone

Trenton Group (Coburn, 

Salona, and Nealmont 

Formations, undivided)

System or series Middle Devonian Middle Devonian Upper Silurian Lower Devonian Upper Ordovician

Formation top (relative to KB) (ft) -4,863 -5,230 -8,956 -8,555 -7,614

Formation top (relative to GL) (ft) -4,850 -5,220 -8,940 -8,532 -7,601

Formation top (relative to SL) (ft) -3,811 -4,100 -6,417 -6,082 -5,951

Formation 28 Oriskany Sandstone Ridgeley Sandstone Salina Group (lower part) Mandata Shale Millbrig Bentonite Bed

System or series Lower Devonian Lower Devonian Upper Silurian Lower Devonian Upper Ordovician

Formation top (relative to KB) (ft) -4,872 -5,237 -9,786 -8,800 -8,010

Formation top (relative to GL) (ft) -4,859 -5,227 -9,770 -8,777 -7,997

Formation top (relative to SL) (ft) -3,820 -4,107 -7,247 -6,327 -6,347
50 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number 1 2 3 4 5 

American Petroleum Institute 

number 34–043–20011 34–093–20794 34–103–21143 34–151–21081 34–029–20648 

Lease name No. 1 Krysik-Wakefield No. 1 A and A Born No. 1–A F.L. Smith Estate No. 1–381 B. Westfall No. 3 Frank Murray 

Permanent datum Ground level NA Ground level Ground level Ground level 

Ground level elevation (ft) 822.45 848 1,185.5 1,137.3 1,183.3 

Kelly bushing elevation (ft) 828.45 848 1,200 1,144.3 1,193 

Measured from KB (6 ft APD) GL KB (14.5 ft APD) KB (7 ft APD) KB (9.7 ft APD) 

Drill depth (ft) 4,463 4,591 7,040 7,961 10,242 

KB elevation - GL elevation (ft) 6.0 0.0 14.5 7.0 9.7 

Formation 29

Nolichucky Shale of 

Conasauga Group Kerbel Formation

Black River Group 

(Millbrig Bentonite Bed at top) Deicke Bentonite Bed

Lower Silurian carbonates and 

shales (undivided) 

System or series Upper Cambrian Upper Cambrian Upper Ordovician Upper Ordovician Lower Silurian 

Formation top (relative to KB) (ft) -4,025 -4,104 -5,143 -6,559 -5,730 

Formation top (relative to GL) (ft) -4,019 -4,104 -5,128.5 -6,552 -5,720.3 

Formation top (relative to SL) (ft) -3,196.55 -3,256 -3,943 -5,414.7 -4,537 

Formation 30

Maryville Limestone of 

Conasauga Group

Nolichucky Shale of 

Conasauga Group Deicke Bentonite Bed Wells Creek formation

“Clinton” sandstone, Cabot Head 

Shale, and Medina sandstone 

(undivided) 

System or series Upper Cambrian Upper Cambrian Upper Ordovician Middle Ordovician Lower Silurian 

Formation top (relative to KB) (ft) -4,085 -4,141 -5,154 -7,220 -5,783 

Formation top (relative to GL) (ft) -4,079 -4,141 -5,139.5 -7,213 -5,773.3 

Formation top (relative to SL) (ft) -3,256.55 -3,293 -3,954 -6,075.7 -4,590 

Formation 31 Mount Simon Sandstone

Maryville Limestone of 

Conasauga Group Wells Creek formation

Knox Dolomite 

(Rose Run sandstone) Queenston Shale 

System or series Upper Cambrian Upper Cambrian Middle Ordovician Upper Cambrian Upper Ordovician 

Formation top (relative to KB) (ft) -4,353 -4,203 -5,740 -7,273 -5,997 

Formation top (relative to GL) (ft) -4,347 -4,203 -5,725.5 -7,266 -5,987.3 

Formation top (relative to SL) (ft) -3,524.55 -3,355 -4,540 -6,128.7 -4,804 
Appendix A 51

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number

American Petroleum Institute 

number

Lease name

Permanent datum

Ground level elevation (ft)

Kelly bushing elevation (ft)

Measured from

Drill depth (ft)

KB elevation - GL elevation (ft)

6

47–029–00080

No. 1 S. Minesinger

Ground level

1,039

1,052

KB (13 ft APD)

10,387

13.0

7

37–007–20060

No. 1 Richard J. Ashcroft

Ground level

1,120

1,130

KB (10 ft APD)

7,590

10.0

8

37–051–20056

No. 1 E.C. Ricks

Ground level

2,523

2,539

KB (16 ft APD)

12,041

16.0

9

37–111–20045

No. 1 Leonard Svetz

Ground level

2,450

2,473

KB (23 ft APD)

21,460

23.0

10

37–009–20034

No. 1 Schellsburg

Ground level

1,650

1,663

KB (13 ft APD)

11,850

13.0

11

37–009–20060

No. 1 Fred Steele

Ground level

1,162

1,189

GL

15,500

27.0

Formation 29

Licking Creek Limestone 

of Helderberg Group Licking Creek Limestone Wills Creek Formation

Corriganville and 

New Creek Limestones 

(undivided) Deicke Bentonite Bed

System or series Lower Devonian Lower Devonian Upper Silurian Lower Devonian Upper Ordovician

Formation top (relative to KB) (ft) -4,938 -5,300 -9,990 -8,820 -8,050

Formation top (relative to GL) (ft) -4,925 -5,290 -9,974 -8,797 -8,037

Formation top (relative to SL) (ft) -3,886 -4,170 -7,451 -6,347 -6,387

Formation 30

Mandata Shale of 

Helderberg Group Mandata Shale Bloomsburg Formation

Keyser Formation 

(upper part)

Black River Group 

(Linden Hall, Snyder, 

and Hatter Formations, 

undivided)

System or series Lower Devonian Lower Devonian Upper Silurian

Upper Silurian to Lower 

Devonian Upper Ordovician

Formation top (relative to KB) (ft) -5,062 -5,436 -10,510 -8,900 -8,140

Formation top (relative to GL) (ft) -5,049 -5,426 -10,494 -8,877 -8,127

Formation top (relative to SL) (ft) -4,010 -4,306 -7,971 -6,427 -6,477

Formation 31

Corriganville and 

New Creek Limestones 

(undivided) of 

Helderberg Group

Corriganville and 

New Creek Limestones 

(undivided)

McKenzie Member of 

Mifflintown Formation

Tonoloway Formation 

(intertongues with 

Salina Group equivalent 

including halite in 

lower 200 ft?) Loysburg Formation

System or series Lower Devonian Lower Devonian Lower to Upper Silurian Upper Silurian

Middle to Upper 

Ordovician

Formation top (relative to KB) (ft) -5,080 -5,445 -10,540 -9,080 -8,510

Formation top (relative to GL) (ft) -5,067 -5,435 -10,524 -9,057 -8,497

Formation top (relative to SL) (ft) -4,028 -4,315 -8,001 -6,607 -6,847
52 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number 1 2 3 4 5 

American Petroleum Institute 

number 34–043–20011 34–093–20794 34–103–21143 34–151–21081 34–029–20648 

Lease name No. 1 Krysik-Wakefield No. 1 A and A Born No. 1–A F.L. Smith Estate No. 1–381 B. Westfall No. 3 Frank Murray 

Permanent datum Ground level NA Ground level Ground level Ground level 

Ground level elevation (ft) 822.45 848 1,185.5 1,137.3 1,183.3 

Kelly bushing elevation (ft) 828.45 848 1,200 1,144.3 1,193 

Measured from KB (6 ft APD) GL KB (14.5 ft APD) KB (7 ft APD) KB (9.7 ft APD) 

Drill depth (ft) 4,463 4,591 7,040 7,961 10,242 

KB elevation - GL elevation (ft) 6.0 0.0 14.5 7.0 9.7 

Formation 32 Metamorphic and igneous rocks Mount Simon Sandstone

Knox Dolomite 

(Copper Ridge dolomite 

(upper part))

Knox Dolomite 

(Copper Ridge dolomite 

(upper part)) Cincinnati group 

System or series Mesoproterozoic Upper Cambrian Upper Cambrian Upper Cambrian Upper Ordovician 

Formation top (relative to KB) (ft) -4,450 -4,466 -5,800 -7,340 -6,725 

Formation top (relative to GL) (ft) -4,444 -4,466 -5,785.5 -7,333 -6,715.3 

Formation top (relative to SL) (ft) -3,621.55 -3,618 -4,600 -6,195.7 -5,532 

Formation 33 Metamorphic and igneous rocks

Knox Dolomite 

(Copper Ridge dolomite 

(B zone and Krysik sandstone))

Knox Dolomite 

(Copper Ridge dolomite 

(B zone and Krysik sandstone)) Utica Shale 

System or series Mesoproterozoic Upper Cambrian Upper Cambrian Upper Ordovician 

Formation top (relative to KB) (ft) -4,585 -5,840 -7,522 -7,492 

Formation top (relative to GL) (ft) -4,585 -5,825.5 -7,515 -7,482.3 

Formation top (relative to SL) (ft) -3,737 -4,640 -6,377.7 -6,299 

Formation 34

Knox Dolomite 

(Copper Ridge dolomite 

(lower part))

Knox Dolomite 

(Copper Ridge dolomite 

(lower part)) Trenton Limestone 

System or series Upper Cambrian Upper Cambrian Upper Ordovician 

Formation top (relative to KB) (ft) -6,021 -7,656 -7,782 

Formation top (relative to GL) (ft) -6,006.5 -7,649 -7,772.3 

Formation top (relative to SL) (ft) -4,821 -6,511.7 -6,589 
Appendix A 53

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number

American Petroleum Institute 

number

Lease name

Permanent datum

Ground level elevation (ft)

Kelly bushing elevation (ft)

Measured from

Drill depth (ft)

KB elevation - GL elevation (ft)

6

47–029–00080

No. 1 S. Minesinger

Ground level

1,039

1,052

KB (13 ft APD)

10,387

13.0

7

37–007–20060

No. 1 Richard J. Ashcroft

Ground level

1,120

1,130

KB (10 ft APD)

7,590

10.0

8

37–051–20056

No. 1 E.C. Ricks

Ground level

2,523

2,539

KB (16 ft APD)

12,041

16.0

9

37–111–20045

No. 1 Leonard Svetz

Ground level

2,450

2,473

KB (23 ft APD)

21,460

23.0

10

37–009–20034

No. 1 Schellsburg

Ground level

1,650

1,663

KB (13 ft APD)

11,850

13.0

11

37–009–20060

No. 1 Fred Steele

Ground level

1,162

1,189

GL

15,500

27.0

Formation 32

Keyser Limestone 

(upper part) of 

Helderberg Group

Keyser Formation 

(upper part)

Rochester Member of 

Mifflintown Formation Wills Creek Formation

Beekmantown Group 

(upper anhydritic 

dolomite)

System or series

Upper Silurian to Lower 

Devonian

Upper Silurian to Lower 

Devonian Lower Silurian Upper Silurian Middle Ordovician

Formation top (relative to KB) (ft) -5,153 -5,522 -10,755 -10,183 -8,700

Formation top (relative to GL) (ft) -5,140 -5,512 -10,739 -10,160 -8,687

Formation top (relative to SL) (ft) -4,101 -4,392 -8,216 -7,710 -7,037

Formation 33

Keyser Limestone 

(middle part) of Helderberg Group (Bass Islands 

Dolomite equivalent)

Keyser Formation 

(middle part) (Bass Islands 

Dolomite equivalent) Keefer Formation Bloomsburg Formation

Beekmantown Group 

(dolomite in upper part)

System or series Upper Silurian Upper Silurian Lower Silurian Upper Silurian Middle Ordovician

Formation top (relative to KB) (ft) -5,172 -5,540 -10,790 -10,615 -9,200

Formation top (relative to GL) (ft) -5,159 -5,530 -10,774 -10,592 -9,187

Formation top (relative to SL) (ft) -4,120 -4,410 -8,251 -8,142 -7,537

Formation 34

Keyser Limestone 

(lower part) of Helderberg 

Group (not equivalent to 

Bass Island Dolomite, 

pinches out in Ohio?)

Keyser Formation 

(lower part) 

(not equivalent to Bass 

Island Dolomite, pinches 

out in Ohio?)

Rose Hill Formation 

(upper part)

McKenzie Member of 

Mifflintown Formation

Beekmantown Group 

(lower anhydritic 

dolomite)

System or series Upper Silurian Upper Silurian Lower Silurian Lower to Upper Silurian Lower Ordovician

Formation top (relative to KB) (ft) -5,238 -5,620 -10,820 -10,650 -10,670

Formation top (relative to GL) (ft) -5,225 -5,610 -10,804 -10,627 -10,657

Formation top (relative to SL) (ft) -4,186 -4,490 -8,281 -8,177 -9,007
54 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number 1 2 3 4 5 

American Petroleum Institute 

number 34–043–20011 34–093–20794 34–103–21143 34–151–21081 34–029–20648 

Lease name No. 1 Krysik-Wakefield No. 1 A and A Born No. 1–A F.L. Smith Estate No. 1–381 B. Westfall No. 3 Frank Murray 

Permanent datum Ground level NA Ground level Ground level Ground level 

Ground level elevation (ft) 822.45 848 1,185.5 1,137.3 1,183.3 

Kelly bushing elevation (ft) 828.45 848 1,200 1,144.3 1,193 

Measured from KB (6 ft APD) GL KB (14.5 ft APD) KB (7 ft APD) KB (9.7 ft APD) 

Drill depth (ft) 4,463 4,591 7,040 7,961 10,242 

KB elevation - GL elevation (ft) 6.0 0.0 14.5 7.0 9.7 

Formation 35

Nolichucky Shale equivalent of 

Conasauga Group

Nolichucky Shale equivalent of 

Conasauga Group

Black River Group 

(Millbrig Bentonite Bed at top) 

System or series Upper Cambrian Upper Cambrian Upper Ordovician 

Formation top (relative to KB) (ft) -6,080 -7,730 -7,922 

Formation top (relative to GL) (ft) -6,065.5 -7,723 -7,912.3 

Formation top (relative to SL) (ft) -4,880 -6,585.7 -6,729 

Formation 36

Maryville Limestone of 

Conasauga Group

Maryville Limestone of 

Conasauga Group Deicke Bentonite Bed 

System or series Upper Cambrian Upper Cambrian Upper Ordovician 

Formation top (relative to KB) (ft) -6,121 -7,789 -7,960 

Formation top (relative to GL) (ft) -6,106.5 -7,782 -7,950.3 

Formation top (relative to SL) (ft) -4,921 -6,644.7 -6,767 

Formation 37 Mount Simon Sandstone Wells Creek formation 

System or series Upper Cambrian Middle Ordovician 

Formation top (relative to KB) (ft) -6,520 -8,596 

Formation top (relative to GL) (ft) -6,505.5 -8,586.3 

Formation top (relative to SL) (ft) -5,320 -7,403 

Formation 38 Metamorphic and igneous rocks

Wells Creek formation 

(unnamed sandstone) 

(St. Peter Sandstone equivalent) 

System or series Mesoproterozoic Middle Ordovician 

Formation top (relative to KB) (ft) -6,573 -8,652 

Formation top (relative to GL) (ft) -6,558.5 -8,642.3 

Formation top (relative to SL) (ft) -5,373 -7,459 
Appendix A 55

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number

American Petroleum Institute 

number

Lease name

Permanent datum

Ground level elevation (ft)

Kelly bushing elevation (ft)

Measured from

Drill depth (ft)

KB elevation - GL elevation (ft)

6

47–029–00080

No. 1 S. Minesinger

Ground level

1,039

1,052

KB (13 ft APD)

10,387

13.0

7

37–007–20060

No. 1 Richard J. Ashcroft

Ground level

1,120

1,130

KB (10 ft APD)

7,590

10.0

8

37–051–20056

No. 1 E.C. Ricks

Ground level

2,523

2,539

KB (16 ft APD)

12,041

16.0

9

37–111–20045

No. 1 Leonard Svetz

Ground level

2,450

2,473

KB (23 ft APD)

21,460

23.0

10

37–009–20034

No. 1 Schellsburg

Ground level

1,650

1,663

KB (13 ft APD)

11,850

13.0

11

37–009–20060

No. 1 Fred Steele

Ground level

1,162

1,189

GL

15,500

27.0

Formation 35 Salina Group (upper part) Salina Group (upper part)

Rose Hill Formation 

(dolomite)

Keefer Formation and 

Rochester Member of 

Mifflintown Formation 

(undivided)

Beekmantown Group 

(dolomite in lower part)

System or series Upper Silurian Upper Silurian Lower Silurian Lower Silurian Lower Ordovician

Formation top (relative to KB) (ft) -5,270 -5,655 -11,220 -10,883 -11,010

Formation top (relative to GL) (ft) -5,257 -5,645 -11,204 -10,860 -10,997

Formation top (relative to SL) (ft) -4,218 -4,525 -8,681 -8,410 -9,347

Formation 36 Salina Group (halite zone) Salina Group (halite zone)

Rose Hill Formation 

(lower part)

Rose Hill Formation 

(upper part)

Mines Dolomite Member 

of Gatesburg Formation

System or series Upper Silurian Upper Silurian Lower Silurian Lower Silurian Upper Cambrian

Formation top (relative to KB) (ft) -5,418 -5,810 -11,254 -10,945 -11,520

Formation top (relative to GL) (ft) -5,405 -5,800 -11,238 -10,922 -11,507

Formation top (relative to SL) (ft) -4,360 -4,680 -8,715 -8,472 -9,857

Formation 37 Salina Group (lower part) Salina Group (lower part)

Castanea Member of 

Tuscarora Formation

Rose Hill Formation 

(dolomite)

Gatesburg Formation 

(upper sandy member)

System or series Upper Silurian Upper Silurian Lower Silurian Lower Silurian Upper Cambrian

Formation top (relative to KB) (ft) -5,950 -6,452 -11,438 -11,304 -11,703

Formation top (relative to GL) (ft) -5,937 -6,442 -11,422 -11,281 -11,690

Formation top (relative to SL) (ft) -4,898 -5,322 -8,899 -8,831 -10,040

Formation 38 Lockport Dolomite Lockport Dolomite Tuscarora Formation

Rose Run Formation 

(lower part)

System or series Lower to Upper Silurian Lower to Upper Silurian Lower Silurian Lower Silurian

Formation top (relative to KB) (ft) -6,290 -6,660 -11,550 -11,340

Formation top (relative to GL) (ft) -6,277 -6,650 -11,534 -11,317

Formation top (relative to SL) (ft) -5,238 -5,530 -9,011 -8,867
56 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number 1 2 3 4 5 

American Petroleum Institute 

number 34–043–20011 34–093–20794 34–103–21143 34–151–21081 34–029–20648 

Lease name No. 1 Krysik-Wakefield No. 1 A and A Born No. 1–A F.L. Smith Estate No. 1–381 B. Westfall No. 3 Frank Murray 

Permanent datum Ground level NA Ground level Ground level Ground level 

Ground level elevation (ft) 822.45 848 1,185.5 1,137.3 1,183.3 

Kelly bushing elevation (ft) 828.45 848 1,200 1,144.3 1,193 

Measured from KB (6 ft APD) GL KB (14.5 ft APD) KB (7 ft APD) KB (9.7 ft APD) 

Drill depth (ft) 4,463 4,591 7,040 7,961 10,242 

KB elevation - GL elevation (ft) 6.0 0.0 14.5 7.0 9.7 

Formation 39

Knox Dolomite 

(Beekmantown dolomite) 

System or series Lower Ordovician 

Formation top (relative to KB) (ft) -8,671 

Formation top (relative to GL) (ft) -8,661.3 

Formation top (relative to SL) (ft) -7,478 

Formation 40

Knox Dolomite 

(Rose Run sandstone) 

System or series Upper Cambrian 

Formation top (relative to KB) (ft) -8,890 

Formation top (relative to GL) (ft) -8,880.3 

Formation top (relative to SL) (ft) -7,697 

Formation 41

Knox Dolomite 

(Copper Ridge dolomite 

(upper part)) 

System or series Upper Cambrian 

Formation top (relative to KB) (ft) -9,050 

Formation top (relative to GL) (ft) -9,040.3 

Formation top (relative to SL) (ft) -7,857 

Formation 42

Knox Dolomite 

(Copper Ridge dolomite 

(B zone and Krysik sandstone)) 

System or series Upper Cambrian 

Formation top (relative to KB) (ft) -9,180 

Formation top (relative to GL) (ft) -9,170.3 

Formation top (relative to SL) (ft) -7,987 
Appendix A 57

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number

American Petroleum Institute 

number

Lease name

Permanent datum

Ground level elevation (ft)

Kelly bushing elevation (ft)

Measured from

Drill depth (ft)

KB elevation - GL elevation (ft)

6

47–029–00080

No. 1 S. Minesinger

Ground level

1,039

1,052

KB (13 ft APD)

10,387

13.0

7

37–007–20060

No. 1 Richard J. Ashcroft

Ground level

1,120

1,130

KB (10 ft APD)

7,590

10.0

8

37–051–20056

No. 1 E.C. Ricks

Ground level

2,523

2,539

KB (16 ft APD)

12,041

16.0

9

37–111–20045

No. 1 Leonard Svetz

Ground level

2,450

2,473

KB (23 ft APD)

21,460

23.0

10

37–009–20034

No. 1 Schellsburg

Ground level

1,650

1,663

KB (13 ft APD)

11,850

13.0

11

37–009–20060

No. 1 Fred Steele

Ground level

1,162

1,189

GL

15,500

27.0

Formation 39 Keefer Sandstone Keefer Sandstone

Tuscarora 

Formation-Juniata 

Formation transition zone

Castanea Member of 

Tuscarora Formation

System or series Lower Silurian Lower Silurian Upper Ordovician(?) Lower Silurian

Formation top (relative to KB) (ft) -6,580 -7,058 -11,907 -11,525

Formation top (relative to GL) (ft) -6,567 -7,048 -11,891 -11,502

Formation top (relative to SL) (ft) -5,528 -5,928 -9,368 -9,052

Formation 40 Rochester Shale

Rose Hill Formation 

(Rochester Shale 

equivalent) Juniata Formation Tuscarora Formation

System or series Lower Silurian Lower Silurian Upper Ordovician Lower Silurian

Formation top (relative to KB) (ft) -6,600 -7,065 -12,045 -11,556

Formation top (relative to GL) (ft) -6,587 -7,055 -12,029 -11,533

Formation top (relative to SL) (ft) -5,548 -5,935 -9,506 -9,083

Formation 41

Lower Silurian carbonates 

and shales (undivided)

Rose Hill Formation 

(Lower Silurian 

carbonates and shales, 

undivided, equivalent)

Tuscarora 

Formation-Juniata 

Formation transition zone

System or series Lower Silurian Lower Silurian Upper Ordovician(?)

Formation top (relative to KB) (ft) -6,755 -7,226 -11,875

Formation top (relative to GL) (ft) -6,742 -7,216 -11,852

Formation top (relative to SL) (ft) -5,703 -6,096 -9,402

Formation 42

“Clinton” sandstone, Cabot 

Head Shale, and Medina 

sandstone (undivided) Medina Group Juniata Formation

System or series Lower Silurian Lower Silurian Upper Ordovician

Formation top (relative to KB) (ft) -6,828 -7,320 -12,010

Formation top (relative to GL) (ft) -6,815 -7,310 -11,987

Formation top (relative to SL) (ft) -5,776 -6,190 -9,537
58 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number 1 2 3 4 5 

American Petroleum Institute 

number 34–043–20011 34–093–20794 34–103–21143 34–151–21081 34–029–20648 

Lease name No. 1 Krysik-Wakefield No. 1 A and A Born No. 1–A F.L. Smith Estate No. 1–381 B. Westfall No. 3 Frank Murray 

Permanent datum Ground level NA Ground level Ground level Ground level 

Ground level elevation (ft) 822.45 848 1,185.5 1,137.3 1,183.3 

Kelly bushing elevation (ft) 828.45 848 1,200 1,144.3 1,193 

Measured from KB (6 ft APD) GL KB (14.5 ft APD) KB (7 ft APD) KB (9.7 ft APD) 

Drill depth (ft) 4,463 4,591 7,040 7,961 10,242 

KB elevation - GL elevation (ft) 6.0 0.0 14.5 7.0 9.7 

Formation 43

Knox Dolomite 

(Copper Ridge dolomite 

(lower part)) 

System or series Upper Cambrian 

Formation top (relative to KB) (ft) -9,310 

Formation top (relative to GL) (ft) -9,300.3 

Formation top (relative to SL) (ft) -8,117 

Formation 44

Nolichucky Shale equivalent of 

Conasauga Group 

System or series Upper Cambrian 

Formation top (relative to KB) (ft) -9,420 

Formation top (relative to GL) (ft) -9,410.3 

Formation top (relative to SL) (ft) -8,227 

Formation 45

Maryville Limestone of 

Conasauga Group 

System or series Upper Cambrian 

Formation top (relative to KB) (ft) -9,486 

Formation top (relative to GL) (ft) -9,476.3 

Formation top (relative to SL) (ft) -8,293 

Formation 46 Mount Simon Sandstone 

System or series Upper Cambrian 

Formation top (relative to KB) (ft) -10,078 

Formation top (relative to GL) (ft) -10,068.3 

Formation top (relative to SL) (ft) -8,885 
Appendix A 59

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number

American Petroleum Institute 

number

Lease name

Permanent datum

Ground level elevation (ft)

Kelly bushing elevation (ft)

Measured from

Drill depth (ft)

KB elevation - GL elevation (ft)

6

47–029–00080

No. 1 S. Minesinger

Ground level

1,039

1,052

KB (13 ft APD)

10,387

13.0

7

37–007–20060

No. 1 Richard J. Ashcroft

Ground level

1,120

1,130

KB (10 ft APD)

7,590

10.0

8

37–051–20056

No. 1 E.C. Ricks

Ground level

2,523

2,539

KB (16 ft APD)

12,041

16.0

9

37–111–20045

No. 1 Leonard Svetz

Ground level

2,450

2,473

KB (23 ft APD)

21,460

23.0

10

37–009–20034

No. 1 Schellsburg

Ground level

1,650

1,663

KB (13 ft APD)

11,850

13.0

11

37–009–20060

No. 1 Fred Steele

Ground level

1,162

1,189

GL

15,500

27.0

Formation 43 Queenston Shale Queenston Shale Bald Eagle Formation

System or series Upper Ordovician Upper Ordovician Upper Ordovician

Formation top (relative to KB) (ft) -7,014 -7,560 -13,000

Formation top (relative to GL) (ft) -7,001 -7,550 -12,977

Formation top (relative to SL) (ft) -5,962 -6,430 -10,527

Formation 44 Reedsville Shale Reedsville Shale

System or series Upper Ordovician Upper Ordovician

Formation top (relative to KB) (ft) -7,826 -13,382

Formation top (relative to GL) (ft) -7,813 -13,359

Formation top (relative to SL) (ft) -6,774 -10,909

Formation 45 Utica Shale

Antes Shale 

(Utica Shale equivalent)

System or series Upper Ordovician Upper Ordovician

Formation top (relative to KB) (ft) -8,670 -14,720

Formation top (relative to GL) (ft) -8,657 -14,697

Formation top (relative to SL) (ft) -7,618 -12,247

Formation 46 Trenton Limestone

Trenton Group (Coburn, 

Salona, and Nealmont 

Formations, undivided)

System or series Upper Ordovician Upper Ordovician

Formation top (relative to KB) (ft) -8,954 -15,349

Formation top (relative to GL) (ft) -8,941 -15,326

Formation top (relative to SL) (ft) -7,902 -12,876
60 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number 1 2 3 4 5 

American Petroleum Institute 

number 34–043–20011 34–093–20794 34–103–21143 34–151–21081 34–029–20648 

Lease name No. 1 Krysik-Wakefield No. 1 A and A Born No. 1–A F.L. Smith Estate No. 1–381 B. Westfall No. 3 Frank Murray 

Permanent datum Ground level NA Ground level Ground level Ground level 

Ground level elevation (ft) 822.45 848 1,185.5 1,137.3 1,183.3 

Kelly bushing elevation (ft) 828.45 848 1,200 1,144.3 1,193 

Measured from KB (6 ft APD) GL KB (14.5 ft APD) KB (7 ft APD) KB (9.7 ft APD) 

Drill depth (ft) 4,463 4,591 7,040 7,961 10,242 

KB elevation - GL elevation (ft) 6.0 0.0 14.5 7.0 9.7 

Formation 47 

System or series 

Formation top (relative to KB) (ft) 

Formation top (relative to GL) (ft) 

Formation top (relative to SL) (ft) 

Formation 48 

System or series 

Formation top (relative to KB) (ft) 

Formation top (relative to GL) (ft) 

Formation top (relative to SL) (ft) 

Formation 49 

System or series 

Formation top (relative to KB) (ft) 

Formation top (relative to GL) (ft) 

Formation top (relative to SL) (ft) 

Formation 50 

System or series 

Formation top (relative to KB) (ft) 

Formation top (relative to GL) (ft) 

Formation top (relative to SL) (ft) 

Formation 51 

System or series 

Formation top (relative to KB) (ft) 

Formation top (relative to GL) (ft) 

Formation top (relative to SL) (ft) 
Appendix A 61

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number

American Petroleum Institute 

number

Lease name

Permanent datum

Ground level elevation (ft)

Kelly bushing elevation (ft)

Measured from

Drill depth (ft)

KB elevation - GL elevation (ft)

6

47–029–00080

No. 1 S. Minesinger

Ground level

1,039

1,052

KB (13 ft APD)

10,387

13.0

7

37–007–20060

No. 1 Richard J. Ashcroft

Ground level

1,120

1,130

KB (10 ft APD)

7,590

10.0

8

37–051–20056

No. 1 E.C. Ricks

Ground level

2,523

2,539

KB (16 ft APD)

12,041

16.0

9

37–111–20045

No. 1 Leonard Svetz

Ground level

2,450

2,473

KB (23 ft APD)

21,460

23.0

10

37–009–20034

No. 1 Schellsburg

Ground level

1,650

1,663

KB (13 ft APD)

11,850

13.0

11

37–009–20060

No. 1 Fred Steele

Ground level

1,162

1,189

GL

15,500

27.0

Formation 47 Millbrig Bentonite Bed Millbrig Bentonite Bed

System or series Upper Ordovician Upper Ordovician

Formation top (relative to KB) (ft) -9,110 -15,580

Formation top (relative to GL) (ft) -9,097 -15,557

Formation top (relative to SL) (ft) -8,058 -13,107

Formation 48 Deicke Bentonite Bed Deicke Bentonite Bed

System or series Upper Ordovician Upper Ordovician

Formation top (relative to KB) (ft) -9,158 -15,615

Formation top (relative to GL) (ft) -9,145 -15,592

Formation top (relative to SL) (ft) -8,106 -13,142

Formation 49 Black River Group

Trenton Group (Salona 

and Nealmont Formations, 

undivided) (fault at top)

System or series Upper Ordovician Upper Ordovician

Formation top (relative to KB) (ft) -9,215 -15,710

Formation top (relative to GL) (ft) -9,202 -15,687

Formation top (relative to SL) (ft) -8,163 -13,237

Formation 50

Loysburg Formation 

equivalent Millbrig Bentonite Bed

System or series

Middle to Upper 

Ordovician Upper Ordovician

Formation top (relative to KB) (ft) -9,625 -15,780

Formation top (relative to GL) (ft) -9,612 -15,757

Formation top (relative to SL) (ft) -8,573 -13,307

Formation 51 Wells Creek formation Deicke Bentonite Bed

System or series Middle Ordovician Upper Ordovician

Formation top (relative to KB) (ft) -9,850 -15,820

Formation top (relative to GL) (ft) -9,837 -15,797

Formation top (relative to SL) (ft) -8,798 -13,347
62 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number 1 2 3 4 5 

American Petroleum Institute 

number 34–043–20011 34–093–20794 34–103–21143 34–151–21081 34–029–20648 

Lease name No. 1 Krysik-Wakefield No. 1 A and A Born No. 1–A F.L. Smith Estate No. 1–381 B. Westfall No. 3 Frank Murray 

Permanent datum Ground level NA Ground level Ground level Ground level 

Ground level elevation (ft) 822.45 848 1,185.5 1,137.3 1,183.3 

Kelly bushing elevation (ft) 828.45 848 1,200 1,144.3 1,193 

Measured from KB (6 ft APD) GL KB (14.5 ft APD) KB (7 ft APD) KB (9.7 ft APD) 

Drill depth (ft) 4,463 4,591 7,040 7,961 10,242 

KB elevation - GL elevation (ft) 6.0 0.0 14.5 7.0 9.7 

Formation 52 

System or series 

Formation top (relative to KB) (ft) 

Formation top (relative to GL) (ft) 

Formation top (relative to SL) (ft) 

Formation 53 

System or series 

Formation top (relative to KB) (ft) 

Formation top (relative to GL) (ft) 

Formation top (relative to SL) (ft) 

Formation 54 

System or series 

Formation top (relative to KB) (ft) 

Formation top (relative to GL) (ft) 

Formation top (relative to SL) (ft) 

Formation 55 

System or series 

Formation top (relative to KB) (ft) 

Formation top (relative to GL) (ft) 

Formation top (relative to SL) (ft) 
Appendix A 63

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number

American Petroleum Institute 

number

Lease name

Permanent datum

Ground level elevation (ft)

Kelly bushing elevation (ft)

Measured from

Drill depth (ft)

KB elevation - GL elevation (ft)

6

47–029–00080

No. 1 S. Minesinger

Ground level

1,039

1,052

KB (13 ft APD)

10,387

13.0

7

37–007–20060

No. 1 Richard J. Ashcroft

Ground level

1,120

1,130

KB (10 ft APD)

7,590

10.0

8

37–051–20056

No. 1 E.C. Ricks

Ground level

2,523

2,539

KB (16 ft APD)

12,041

16.0

9

37–111–20045

No. 1 Leonard Svetz

Ground level

2,450

2,473

KB (23 ft APD)

21,460

23.0

10

37–009–20034

No. 1 Schellsburg

Ground level

1,650

1,663

KB (13 ft APD)

11,850

13.0

11

37–009–20060

No. 1 Fred Steele

Ground level

1,162

1,189

GL

15,500

27.0

Formation 52

Wells Creek formation 

(unnamed sandstone) 

(St. Peter Sandstone 

equivalent)

Black River Group 

(Linden Hall, Snyder, 

and Hatter Formations, 

undivided)

System or series Middle Ordovician Upper Ordovician

Formation top (relative to KB) (ft) -9,925 -15,970

Formation top (relative to GL) (ft) -9,912 -15,947

Formation top (relative to SL) (ft) -8,873 -13,497

Formation 53 Beekmantown Dolomite Loysburg Formation

System or series Lower Ordovician

Middle to Upper 

Ordovician

Formation top (relative to KB) (ft) -9,940 -16,640

Formation top (relative to GL) (ft) -9,927 -16,617

Formation top (relative to SL) (ft) -8,888 -14,167

Formation 54

Beekmantown Group 

(upper anhydritic 

dolomite)

System or series Middle Ordovician

Formation top (relative to KB) (ft) -17,000

Formation top (relative to GL) (ft) -16,977

Formation top (relative to SL) (ft) -14,527

Formation 55

Beekmantown Group 

(dolomite in upper part, 

above Knox unconformity)

System or series Middle Ordovician

Formation top (relative to KB) (ft) -17,320

Formation top (relative to GL) (ft) -17,297

Formation top (relative to SL) (ft) -14,847
64 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number 1 2 3 4 5 

American Petroleum Institute 

number 34–043–20011 34–093–20794 34–103–21143 34–151–21081 34–029–20648 

Lease name No. 1 Krysik-Wakefield No. 1 A and A Born No. 1–A F.L. Smith Estate No. 1–381 B. Westfall No. 3 Frank Murray 

Permanent datum Ground level NA Ground level Ground level Ground level 

Ground level elevation (ft) 822.45 848 1,185.5 1,137.3 1,183.3 

Kelly bushing elevation (ft) 828.45 848 1,200 1,144.3 1,193 

Measured from KB (6 ft APD) GL KB (14.5 ft APD) KB (7 ft APD) KB (9.7 ft APD) 

Drill depth (ft) 4,463 4,591 7,040 7,961 10,242 

KB elevation - GL elevation (ft) 6.0 0.0 14.5 7.0 9.7 

Formation 56 

System or series 

Formation top (relative to KB) (ft) 

Formation top (relative to GL) (ft) 

Formation top (relative to SL) (ft) 

Formation 57 

System or series 

Formation top (relative to KB) (ft) 

Formation top (relative to GL) (ft) 

Formation top (relative to SL) (ft) 

Formation 58 

System or series 

Formation top (relative to KB) (ft) 

Formation top (relative to GL) (ft) 

Formation top (relative to SL) (ft) 

Formation 59 

System or series 

Formation top (relative to KB) (ft) 

Formation top (relative to GL) (ft) 

Formation top (relative to SL) (ft) 
Appendix A 65

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number

American Petroleum Institute 

number

Lease name

Permanent datum

Ground level elevation (ft)

Kelly bushing elevation (ft)

Measured from

Drill depth (ft)

KB elevation - GL elevation (ft)

6

47–029–00080

No. 1 S. Minesinger

Ground level

1,039

1,052

KB (13 ft APD)

10,387

13.0

7

37–007–20060

No. 1 Richard J. Ashcroft

Ground level

1,120

1,130

KB (10 ft APD)

7,590

10.0

8

37–051–20056

No. 1 E.C. Ricks

Ground level

2,523

2,539

KB (16 ft APD)

12,041

16.0

9

37–111–20045

No. 1 Leonard Svetz

Ground level

2,450

2,473

KB (23 ft APD)

21,460

23.0

10

37–009–20034

No. 1 Schellsburg

Ground level

1,650

1,663

KB (13 ft APD)

11,850

13.0

11

37–009–20060

No. 1 Fred Steele

Ground level

1,162

1,189

GL

15,500

27.0

Formation 56

Beekmantown Group 

(dolomite in upper part, 

below Knox unconformity)

System or series Lower Ordovician

Formation top (relative to KB) (ft) -17,830

Formation top (relative to GL) (ft) -17,807

Formation top (relative to SL) (ft) -15,357

Formation 57

Beekmantown Group 

(middle anhydritic 

dolomite)

System or series Lower Ordovician

Formation top (relative to KB) (ft) -17,930

Formation top (relative to GL) (ft) -17,907

Formation top (relative to SL) (ft) -15,457

Formation 58

Beekmantown Group 

(dolomite in lower part)

System or series Lower Ordovician

Formation top (relative to KB) (ft) -18,420

Formation top (relative to GL) (ft) -18,397

Formation top (relative to SL) (ft) -15,947

Formation 59

Mines Dolomite Member 

of Gatesburg Formation

System or series Upper Cambrian

Formation top (relative to KB) (ft) -20,740

Formation top (relative to GL) (ft) -20,717

Formation top (relative to SL) (ft) -18,267
66 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number 1 2 3 4 5 

American Petroleum Institute 

number 34–043–20011 34–093–20794 34–103–21143 34–151–21081 34–029–20648 

Lease name No. 1 Krysik-Wakefield No. 1 A and A Born No. 1–A F.L. Smith Estate No. 1–381 B. Westfall No. 3 Frank Murray 

Permanent datum Ground level NA Ground level Ground level Ground level 

Ground level elevation (ft) 822.45 848 1,185.5 1,137.3 1,183.3 

Kelly bushing elevation (ft) 828.45 848 1,200 1,144.3 1,193 

Measured from KB (6 ft APD) GL KB (14.5 ft APD) KB (7 ft APD) KB (9.7 ft APD) 

Drill depth (ft) 4,463 4,591 7,040 7,961 10,242 

KB elevation - GL elevation (ft) 6.0 0.0 14.5 7.0 9.7 

Formation 60 

System or series 

Formation top (relative to KB) (ft) 

Formation top (relative to GL) (ft) 

Formation top (relative to SL) (ft) 

Formation 61 

System or series 

Formation top (relative to KB) (ft) 

Formation top (relative to GL) (ft) 

Formation top (relative to SL) (ft) 

Formation 62 

System or series 

Formation top (relative to KB) (ft) 

Formation top (relative to GL) (ft) 

Formation top (relative to SL) (ft) 
Appendix A 67

Appendix A. Table summarizing drill holes, stratigraphic units, and depths of stratigraphic units in cross section C–C’.—Continued

[Abbreviations: APD, above permanent datum; ft, feet; GL, ground level; KB, kelly bushing; NA, not available; SL, sea level]

Drill-hole number

American Petroleum Institute 

number

Lease name

Permanent datum

Ground level elevation (ft)

Kelly bushing elevation (ft)

Measured from

Drill depth (ft)

KB elevation - GL elevation (ft)

6

47–029–00080

No. 1 S. Minesinger

Ground level

1,039

1,052

KB (13 ft APD)

10,387

13.0

7

37–007–20060

No. 1 Richard J. Ashcroft

Ground level

1,120

1,130

KB (10 ft APD)

7,590

10.0

8

37–051–20056

No. 1 E.C. Ricks

Ground level

2,523

2,539

KB (16 ft APD)

12,041

16.0

9

37–111–20045

No. 1 Leonard Svetz

Ground level

2,450

2,473

KB (23 ft APD)

21,460

23.0

10

37–009–20034

No. 1 Schellsburg

Ground level

1,650

1,663

KB (13 ft APD)

11,850

13.0

11

37–009–20060

No. 1 Fred Steele

Ground level

1,162

1,189

GL

15,500

27.0

Formation 60

Gatesburg Formation 

(upper sandy member) 

(Rose Run sandstone 

equivalent)

System or series Upper Cambrian

Formation top (relative to KB) (ft) -20,835

Formation top (relative to GL) (ft) -20,812

Formation top (relative to SL) (ft) -18,362

Formation 61

Ore Hill Limestone 

Member equivalent of 

Gatesburg Formation

System or series Upper Cambrian

Formation top (relative to KB) (ft) -21,320

Formation top (relative to GL) (ft) -21,297

Formation top (relative to SL) (ft) -18,847

Formation 62

Gatesburg Formation 

(lower sandy member?)

System or series Upper Cambrian

Formation top (relative to KB) (ft) -21,453

Formation top (relative to GL) (ft) -21,430

Formation top (relative to SL) (ft) -18,980

Appendix B.—Scale, Units, and Depths for Gamma-Ray Logging Runs
70 Geologic Cross Section C–C’ Through the Appalachian Basin

Appendix B. Scale, units, and depths for gamma-ray logging units.

[Abbreviations are as follows: API, American Petroleum Institute; ft, feet; KB, kelly bushing; nd, no data; TD, total depth; ft, 

feet]

Well 

number

Scale and units Depths of selected logged 

intervals

Casing shoe 

location(s)

1 0–200 API units

200–400 backup scale

KB to TD 411 ft below KB.

2 0–15 micro Roentgen per hour 60 ft below KB to TD nd

3 0–10 micrograms radium equivalents per ton

10–20 backup scale

20–30 backup scale

KB to TD 491 ft below KB.

4 0–200 API units

200–400 backup scale

40 ft below KB to TD 870 ft below KB.

5 0–200 API units

200–400 backup scale

15 ft below KB to TD 925 ft below KB.

6 0–150 API units

0–200 API units

200–400 backup scale

KB to 1,027 ft

1,000 ft below KB to TD

nd

7 0–200 API units

0–200 API units

KB to 1,282 ft

1,272 ft below KB to TD

nd

8 0–250 API units

0–200 API units

0–150 API units

KB to 9,320 ft

9,320 ft below KB to 11,400 ft

11,4000 ft below KB to TD

1,385 ft below KB.

9,388 ft below KB.

9 0–200 API units

0–200 API units

200–400 backup scale

0–200 API units

70 ft below KB to 1,450 ft

1,450 ft below KB to 10,250 ft

10,250 ft below KB to TD

110 ft below KB.

10 0–150 API units

150–300 backup scale

8 ft below KB to TD 3,120 ft below KB.

11 0–200 API units 146 ft below KB to TD 608 ft below KB.

11,338 ft below KB.

Ryder and others—Geologic Cross Section C–C’ Through the Appalachian Basin—SIM 3172

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