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HORVATH, Allan Leo, 1925- STRATIGRAPHY OF THE SILURIAN ROCKS OF SOUTHERN OHIO AND ADJACENT PARTS OF WEST VIRGINIA, KENTUCKY, AND INDIANA.

The Ohio State University, Ph.D., 1964 Geology

University Microfilms, Inc., Ann Arbor, Michigan STRATIGRAPHY OF THE SILURIAN ROCKS OF SOUTHERN

OHIO AND ADJACEHT PARTS OF WEST VIRGINIA,

KENTUCKY, AND INDIANA

DISSERTATION

Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio S ta te U n iv e r sity

By

Allan Leo Horvath, B.S., 14.S

■K -M- # -Jc

The Ohio S ta te U n iv e rsity 196U

Approved by

A dviser Department of Geology ACKNOWLEDGMENTS

The writer wishes to express his gratitude to R. L. Bates of

The Ohio State University, Department of Geology, who acted as adviser

and gave liberally of his time to supervise the preparation of this manuscript; to C. H. Summerson, who helped acquaint the writer with

various characteristics of the Silurian outcrop during several trips

into the field; to W. C, Sweet for technical information; to W. L.

Calvert and other members of the Ohio Geological Survey who provided

data and working space; and to Continental Oil Company, whose release

of critical cores and geophysical logs made the investigation possible.

I wish to thank Truman Bennett, for his encouragement and help

in obtaining information, and Dale Sparling for advice and criticism .

Information and fa cilities were made available to me by P. H. Price

and V/. R. McCord of the West Virginia Geological Survey; J. B. Patton

of the Indiana Geological Survey; E. N. Wilson and J. H. Poteet of

the Kentucky Geological Survey; and officials of some of the major

o il companies.

My thanks are also extended to two earlier investigators of

the Niagaran in Ohio. D. A. Busch gave suggestions and R. S. Bowman

provided advice and an extended tour of the Niagaran and Cayugan

exposures at Plum Run stone quarry. Finally I am indebted to the

Department of Geology of Ohio Btate University for financial aid from the Friends of Orton Hall fund and the Bownocker fund, which helped defray field and manuscript expenses.

i i i VITA

July 6, 1925 Born - Dayton, Ohio

19£6 .... B.S., University of Dayton, Dayton, Ohio

1957 .... M.S., University of Michigan, Ann Arbor, . Michigan

1957-1960 . Exploration geologist, Atlantic Refining Company, R osw ell, New Mexico

I96O-I96U . Teaching Assistant, Department of Geology, The Ohio State University, Columbus, Ohio

FIELDS OF STUDI

Major Field: Geology

Studies in Paleozoic Stratigraphy. Professors R. L. Bates, W. C. Sw eet, M. P. N eiss and C. K. Summerson

Studies in Paleontology. Professors W. C. Sweet and A. La Rocque

IV CONTENTS

Page

ACKN O'.VLEDGi'iSN T S ...... i i

V IT A ...... iv

ILLUSTRATIONS...... v i i

I . INTRODUCTION ...... 1

Purpose of Investigation ...... 1 Aethods of Investigation ...... 3

II. oTRiiTIGRAPHY...... 8

Aedina Group ...... 12 B ra s s fie ld form ation ...... 13 T uscarora Form ation ...... 19 Cabot Head F o rm a tio n ...... 21 plum Creek c l a y ...... 23 otratigraphic Relations within the Aedina Group ...... 2k

Clinton Group ...... 2$ Oldham Form ation ...... 27 Lulbegrud Clay ...... 30 Dayton Formation ...... 31 VJaco f o r m a tio n ...... 33 B still Formation ...... 3U Rose Hill form ation ...... 36 Osgood shale ...... UO Eisner Formation ...... b2 Laurel lim estone ...... 16 Aassie shale ...... kl Eluphemia d o l o m i t e ...... i;7 Springfield dolom ite ...... Ij.ti Reefer Formation ...... k9 Rochester Formation ...... 33 Correlation Problems in bestern Ohio and Indiana ...... 33 Aississinewa shale ...... 60 Stratigraphic Relations within the Clinton Group ...... 62

v Page

Lockport Group ...... 65 Lilley Formation ...... 66 Cedarville formation ...... 70 Peebles Formation ...... 72 McKenzie Formation ...... 75 Liston Creek lim estone ...... 7 9 Huntington limestone ...... 80 New Corydon limestone ...... 82 otratigraphic Relations within the Lockport Group ...... 83

oalina Group ...... 86 Greenfield formation ...... 87 Kokomo lim e s to n e ...... 92 Williamsport sandstone ...... 9k Wills Creek Form ation ...... 97 Tymochtee Formation ...... 101 Tonoloway F o r m a t i o n ...... 106 Raisin River Formation ...... 110 btratigraphic Relations witnin tne Galina Group ...... 116 Keyser Limestone ...... 118

I I I . COHCLUgIOWo Ai\D GlOLUGIC H IC T O R I...... 123

AFPiSNUIKjSo...... 1R1

Appendix a Attinger W ell...... lit l Appendix b rdller We 1 1 ...... 1U5

AEFSitEHCEo G li'E D ...... 150

v i ILLUSTRATIONS

Figure Page

1 Area of investigation ...... 1

2 Location of lines of principal cross-section and important outcrop localities ...... 6

3 Proposed stratigraphic equivalents for the oilurian . . . 9

U Diagram showing regional stratigraphic relations for the medina G roup ...... 13

5 Diagram showing regional stratigraphic relations for the Clinton Group ...... 26

6 Cross-section showing Oldham-Brassfield relations .... 26

7 Paleogeographic map of the C linton ...... $2

6 Cross-section from north-central Indiana to central O h i o ...... $9

9 Diagram showing regional stratigraphic relations for the Lockport G roup ...... 67

10 cross-section from southwestern Ontario to eastern O h i o ...... '...... 65

11 Diagram showing regional stratigraphic relations for the Salina Group ...... 66

Table 1 Well Locations ...... 133

2 Well Data ...... 137

P la te I Cross-section A-5 II Cross-section C-D III Cross-section ii-F v i i INTRODUCTION

This study of Silurian rocks deals with an area of approxi­ mately U0,000 square miles in Ohio, Kentucky, West Virginia, and border areas of neighboring states, as shown in Figure 1. The

eastern margin is that part of the folded Appalachians along the

Virginia-West Virginia state lin e, extending northward to Cumberland,

Maryland; the western margin is along the Cincinnati arch, paralleling

the Indiana-Ohio state line and continuing southward into north-central

Kentucky. These two marginal areas include major outcrops of Silurian

rocks on opposite sides of the Appalachian basin. The northern boundary extends from Indiana across central Ohio to Pennsylvania; and

the southern boundary extends from Madison County, Kentucky, to

Alleghany County, Virginia. The northern boundary was selected in

order to tie in with the recent Silurian study of Ulteig (1963) in

northern Ohio; the southern, to include type localities for some of

the Silurian formations discussed in the report.

Purpose of Investigation

This investigation of the Silurian strata of southern Ohio

and parts of adjacent states was undertaken with the purpose of

extending into the subsurface the field information obtained by

previous workers. The work of Orton (1871) is noteworthy among the

early field investigations in southern Ohio. Some of his formation

1 names are still in use today. Three of the more recent geologists who described and measured Silurian outcrops in southern Ohio were

Foerste (1935), Busch (1939), and Bowman (1956), Foerste, in a series of investigations from 1896 to 1935, also studied Silurian rocks in southeastern Indiana and Kentucky, A few years earlier,

Cumings and Shrock (1928) worked out much of the Silurian stratigraphy in northern Indiana, On the eastern side of the Appalachian basin,

Swartz and others (1923) correlated the Silurian formations of Mary­ land with the standard section of New York state. Later, Woodward

(19U1) summarized the available information concerning the Silurian strata of West Virginia,

The results of these field investigations spanning approxi­ mately a century contributed much to our knowledge of the Silurian, but at the same time produced a multitude of local formation names.

Usage of these names is often limited by the boundaries of the state or area in which the formations were defined.

Regional subsurface studies by Rittenhouse (19U9) and Freeman

(1951) were major contributions to understanding and correlating

Silurian formations in widely separated parts of the Appalachian basin.

An important part of Freeman's work was the recognition of the in­ fluence of the Cincinnati arch on facies development. The limited information available to these two geologists, however, made it im­ possible to solve many of the problems confronting them. During the last 10 to 15 years, several strategic wells have been drilled by oil companies in Ohio, West Virginia, and Kentucky. It is now possible actually to trace many of the rock units at one outcrop into 3 lithologically equivalent units at a distant outcrop by means of w e ll d a ta .

The major objectives of this study are these:

1) To determine whether various outcrop subdivisions of the Ohio Silurian in present use can be recognized in the subsurface.

2) To trace the Silurian formations from the southern Ohio outcrop eastward into the subsurface and across the Appala­ chian basin into the Virginia-West Virginia outcrop.

3) To trace the Silurian formations in various parts of Ohio into their probable equivalents in northeastern Ken­ tucky, north-central Indiana, and western Maryland.

U) To present a brief geologic history of the region in Silurian time.

Methods of Investigation

Silurian strata, along with younger and older rocks, are ex­ posed at various localities on the Ohio flank of the Cincinnati arch, as shown in Figure 2. Some of the more Important localities which were used to prepare the composite outcrop sections shown on Plates I and II are A-l, section in the gorge south of Clifton, Greene

County, Ohio; A-2, Cedarville quarry on the outskirts of Cedarville,

Greene County, Ohio; C-l, Ralph Rodgers quarry in western Pike County,

Ohio; C-2, section along a creek near "The Point," Highland County,

Ohio; and C-U, outcrop along route Ul near Ohio Brush Creek in Ohio

Township, Adams County, Ohio.

Evidence gained from surface exposures was supplemented by information from two cores that penetrate the Silurian section. These cores, from the M iller and Attinger wells, proved to be the "key" in tracing the formations identified at outcrop into the subsurface. The

\ / £f / j f j ) AREA OF INVESTIGATION APPROXIMATE LIMITS CONTROL OF WELLS SILURIAN SHOWN OUTCROPS. ON CRO& SECTIONS. OTHER CONTROL WELLS. o-r h q a . *1 N On'; o.*° N i e-M i e-M < < n . v -• —-d o o» 100 90 SCALE IN MILES rtf

Area of investigation wells were drilled by Continental Oil Company in late 1961 and early

1962. They are located in Pebble and Perry townships, respectively,

Pike County, Ohio*

A study of the outcrop section within a few miles of the

Attinger well preceded the detailed description of both cores and the integration of their lithologies with the garama-ray-neutron surveys of these wells. The next step was the selection of other wells for which both sample cuttings and geophysical logs were available. Certain control wells were selected and three cross- sections were constructed, as illustrated in Figure 2. Cross-sections

A-B and C-D extend west-east, from west-central Ohio to Maryland, and from southwestern Ohio to eastern West Virginia and Virginia; cross- section E-F extends north-south and connects central Ohio and north­ eastern Kentucky.

During the investigation, sample cuttings from approximately

$0 wells were studied and published descriptions were also consulted.

Idthologic columns for 2 k of these wells are given on the cross- sections. Well cuttings were studied with the aid of a ten-power binocular microscope. Clastic grain size was compared to a standard scale obtained from the Geological Specialty Company. Geophysical logs sought for this study were of the gamma-ray-neutron type; when these were unavailable, self-potential or resistivity logs were sub­ stituted. A **key** well with both cuttings and geophysical log was sometimes used to interpret a nearby well for which only a geo­ physical log was available, or a well with a gap in the lithologic record. Formation tops obtained by this method, and those taken from 6

\ % ^ V I' * \ ^ \ 1 M 1 / V-t 'v'’" '• nd ;' J/ / r- V >-. ■ \ v/>/ %«• s • / vV i s / ~J

'i ' £— J ft i f * i location of lines of principal cross-section an* Important outcrop localities F igu re 8 sample descriptions by Martens (19U5), Freeman (19^1), and various o il companies* are listed in Table 2•

The type localities of many of the formations discussed are in southern Ohio and eastern Kentucky. A few type localities are within 25 miles of the Attinger or M iller wells in Pike County, Ohio.

The subsurface Silurian terminology used in Ohio contains many d riller's terms, such as Big Lime, Newburg or Newburg Sand, and

Packer Shell. Such names are rarely used in this report because their lithologic implications are inadequate and often misleading. STRATIGRAPHY

Some interesting questions suggested by the correlation chart, Figure 3, are set forth below:

In southeastern Ohio the Brassfield formation is partly re­ placed by a tongue of the "Clinton sands." Eastward into West

Virginia, these sands thicken into the Tuscarora formation, which replaces all the Brassfield carbonates.^ Are the "Clinton sands" partly of Lower Niagaran age in West Virginia?

Sedimentary rocks of the Brassfield type thicken eastward

into the basin from the Ohio and Kentucky outcrops, through addition

of shale and carbonate units at the top. Perry (1962) and other geologists consider the added units as part of the Brassfield. Are

these added units in the subsurface equivalent to the Brassfield, or with the Oldham and Plum Creek formations at the outcrop in north-

central Kentucky?

^•The name "Clinton sands" is a driller's subsurface unit in Ohio. A gas-bearing "Clinton limestone" was described by Orton from cuttings -obtained from wells drilled near Lancaster, Ohio, in 1887. Subsequent drilling showed these productive beds to be a series of sandstones separated by varying thicknesses of shale. These sands are custom­ arily divided into 3 units: A lower "2nd Clinton," an intermediate "1st Clinton" and an upper "Stray Clinton." The Lancaster area was the site of the first commercially important "Clinton" production, and the name "Clinton sands" was adopted by drillers seeking this o il and gas reservoir in Ohio. The "Clinton sands" of Ohio are older than, and unrelated to, the Clinton formation of western New York state, and are not a part of the Clinton Group. They can be traced from Ohio into the Medina sandstones of western Pennsylvania and the Tuscarora sand­ stone of West Virginia.

8 RICH- ! HOI© yEL I! A C LI N'TOH LOCK FC'R? 3»LIKA ' I GROUF CREEK surface c a f r u s t u S - p o r c t u C o ra alt . t r i v .V. r l'td a ModLriad .- IKLIANA f.--C KCKOMC ETR OHIO WESTERS ASII RIVER I I RAIS S I R I f GFIELD GFIELD f I R I S FU] IIEKIA FU] p c r e t u O MASS IE CSC COL rS D oroSE m - OHIOS-W crop o r tc u O STRATIGRAFHIC EQUIVOJ-NTA FOR THE SILURIAN SILURIAN THE FOR EQUIVOJ-NTA STRATIGRAFHIC I. I I I S E IUF 3 FIOURF AS ISLANDS BASS C OHIO -C S LILLEY Outcrop-SuLsurface AS S/I S ISL/IID BASS k - RICHMOND II.L 7 S E e WACO - n i c r i . m ET & AS. OHIO ST. EA & CENT. CLSO SAKTiS 'C LISTON ET R NIA IN IRG V WEST WILLIAMS! CRT? WILLIAMS! LI CREEK IS IL W OF KEYSFR LOWFR OE ILL H ROSE KEEFER 10

The Clinton shales show three types of lithology in some wells in east-central Ohio: an upper dolomitic shale or argillaceous dolomite; a middle silty or sandy carbonate; and a lower predominantly green or brownish clay shale. What relationship exists between the

E still formation in southern Ohio and the Clinton shales?

In the subsurface of west-central and northwestern Ohio, the

Bisher, the Alger, and in places the Dayton formations are extremely thin or absent. Are equivalent facies of these strata present or were these formations deposited and then removed by erosion?

The Mississinewa, Liston Creek, Huntington, and Kokomo formations of Indiana were once believed to be normal bedded marine strata. Today geologists believe that these formations are related reef and interreef facies. What relationship then exists between the

Greenfield formation and probable reef accumulations noted in

Lockport sediments from the subsurface of central Ohio?

What is the relationship of the Lilley and Peebles dolomites of southern Ohio to the Lockport dolomite of eastern Ohio and the

McKenzie limestones and shales of West Virginia?

Woodward (19U1) believes the Tonoloway is equivalent to the

Greenfield formation of Ohio. The Tonoloway is presently considered by most geologists to be the uppermost Cayugan formation in West

Virginia. If Woodward's interpretation is correct, then the

Tymochtee formation, which is above the Greenfield in Ohio is equivalent to what formation in West Virginia?

The Raisin River dolomite, (Bass Islands formation of some geologists) has limited areal extent and erratic thickness in Ohio 11 largely as a result of the biluro-Devonian erosional unconformity.

Is this dolomite equivalent to the Keyser formation in Pennsylvania, as proposed by Cate (1961)?

The writer is aware of the wide scope, both geographic and stratigraphic, of the investigation undertaken. However, sufficient information is now available to permit a reasonable explanation for many of the stratigraphic problems in the region. It is hoped that the data included will be of substantial help to future investigators of the Silurian.

It should be noted that the stratigraphic equivalents pro­ posed in this study involve the tracing of rock units from the outcrops in one area into the subsurface and where possible out into outcrops again in a different part of the Appalachian basin. Lithic character­ istics and stratigraphic position are the tools of identification in the subsurface. Age correlations mentioned in the final paragraph or two of each formation are based on the paleontologic investiga­ tions of earlier workers, who correlated the Silurian in southern

Ohio, Maryland, West Virginia, and .Kentucky with the standard oilurian section of Hew York on faunal evidence.

These age designations are included for the reader's informa­ tion, but are not part of the actual investigation since paleontology t is beyond the scope of this study. It should be pointed out that

Figure 3 is not a correlation chart. Time terms are omitted from this chart. According to the rules of stratigraphic nomenclature, groups are rock-stratigraphic terms. Age is implied in correlation of local groups with the standard section of Kew York state where 12 groups are fitted into the Silurian time scale. Confusion will be avoided, if it is remembered, for example, that although Lockport is used as a group name in Ohio, Indiana, West Virginia, New York and other states, the Lockport group and the formations comprising it in one locality are not necessarily correlative (equal in time) to the Lockport Group in another area.

This study, then is concerned with the tracing of outcrops into equivalent subsurface strata which have similar lithology or stratigraphic position. Complications arise from (1) the existence of thicker rock units in the subsurface than on the outcrop, and

(2) changes in facies which are hard to evaluate.

hedina Group

The Hedina Group was named from Kedina, Orleans County, New

York, where red and white sandstones are exposed. This group is essentially the same sequence of rocks once included in the albion beries, except that the hedina Group excludes the Thorold sandstone.

F ish e r (1 959) favors elimination of Albion as a name because it has been used in series, group, and formational senses.

In south-central Ohio, well data show the hedina Group to consist of the Brassfield formation, the 11 Clinton sands," and the

Cabot Head shale. On the flanks of the Cincinnati arch in northern

Kentucky, western Ohio, and Indiana, a single formation, the brass­ field, occupies this interval. The Kedina Group in 'West Virginia includes all beds below the Rose Hill formation and above the

Juniata redbeds. The Tuscarora occupies this stratigraphic p o s itio n . I'UUftUMl fftOMO

FORMATIONS ARC NOT DRAWN TO ANT VERTICAL SCALE

JHORIZONTAL SCALC MILES AL. HORVATH

REGIONAL STRATIGRAPHIC RELATIONS FOR THE MEDINA GROUP FIGURE 4 The Juniata is generally believed to be of Ordovician age, although Chen (196U) has proposed th a t i t i s Lower S ilu r ia n . Chen bases his conclusions on (1) relations of Oswego, Juniata and

Tuscarora sediments which suggest uninterrupted clastic deposition,

(2) occurrence of a strong tectonic unconformity below the Oswego east of the Susquehanna River, Pennsylvania, and (3) change in the depositional environment from Martinsburg to Oswego causing coarser clastic deposits which could be the beginning of a major sedimentary cycle. Chen (196U, p. 6) prefers to place the Silurian-Ordovician boundary between the Martinsburg shale and the Oswego sandstone.

The writer finds Chen's arguments persuasive, but not con­ clusive. In the absence of confirmatory paleontologic or detailed stratigraphic evidence the Juniata should be retained as uppermost

Ordovician. If Chen's proposed classification is accepted, the

Juniata and Oswego would be in ter p r eted as part o f the Lower S ilu r ia n unrepresented in New York and the correlation of the Tuscarora with the standard New York Medina would s till stand.

Some stratigraphers consider the "Belfast bed," which occurs locally at the base of the Brassfield, to be of formation rank.

Foerste (1931, P. 18U) traced this unit into the Brassfield and inter­ preted it as a local facies. An older formation, the Centerville clay, was found by Foerste (1931, p. GU) to occur between the Brass­ field and the underlying Ordovician rocks at a quarry, now flooded, one-half mile northeast of Centerville, Montgomery County, Ohio. The absence of a well-defined exposure, and the uncertainty of distin­ guishing these beds from underlying Ordovician shales in the subsurface, eliminates the Centerville clay from consideration in this paper. The Medina Group in western Ohio and Indiana is composed essentially of the Brassfield formation, although in certain local­ ities thin beds of Cabot Head shale are included.

Brassfield Formation

Orton (1Q71) correlated certain limestones in Ohio with the basal Niagaran unit, the Clinton of New York, on the basis of strati­

graphic position. Foerste (1906, p. 27) gave the name Brassfield to

21 feet of similar limestone exposed in a railroad cut between Brass­

field and Panola in Madison County, Kentucky. In 1909 he applied

this name to the so-called "Clinton limestone" in Ohio that had been

designated by Orton.

The Brassfield consists mostly of carbonate strata, with thin

interbeds of green shale. Most of the rock is limestone, although

the basal zone may be dolomitic. Either two or three units are

recognized, A lower unit, only locally present, consists of greenish-

gray fine-grained argillaceous dolomite or dolomitic limestone, which

is glauconitic and in places silty. Foerste (1896, p. 16U) named

this unit the Belfast bed. The middle unit consists of both fine­

grained and medium- to coarse-grained moderately crinoidal limestone,

generally white to light gray or buff. The upper unit is medium- to

coarse-grained limestone that ranges from light brown or gray-brown

to yellow, pink, or red. One or more layers of calcareous oolitic,

pelletal, or fossiliferous hematite may occur in the upper unit, and

a fairly persistent hematite layer occurs within $ feet of the upper 16 boundary of the Brassfield in most sections; and a coarse "bead bed" with crinoid columnals up to one inch in diameter, has been reported as the top layer at outcrops in southern Ohio and northeastern

Kentucky. The upper unit contains partings and stringers of green clay. In sane areas, including Highland and Adams counties, the middle unit also contains calcareous shale.

The Brassfield presents certain problems in the subsurface.

The formation thickens eastward from the western Ohio outcrop. An analysis of the two cores in Highland County, and records from other wells nearby, indicate that rock strata are added mainly to the top of the Brassfield. In the Miller well these additional beds can be divided into a lower unit consisting of UO feet of greenish-gray shale with a few thin interbedded limestones; a middle unit composed of 6 feet of dolomite and oolitic hematite; and an upper unit con­ taining about 7 feet of green and reddish-brown shale. The Dayton dolomite overlies this upper unit. Some geologists have included these beds in the Brassfield formation, and Perry (1962) has included similar strata in the subsurface of eastern Kentucky in the Brass­ field. The beds are assigned a higher stratigraphic position by the writer and are discussed under the Clinton Group.

Eastward into the basin a facies change takes place in the

Erassfield. East of a line drawn from the eastern border of E lliott

County, Kentucky, northward along the western edge of Lawrence and

Jackson counties, Ohio, and extending across the western one-third of

Vinton, Hocking, and Fairfield Counties, Ohio, part of the Brassfield

is replaced by the wedge edge of the "Clinton sands." See Plate II. West of the zero "Clinton sands" line, the Brassfield In western Licking County and southward along its strike in Fairfield,

Pike, and Scioto counties, Ohio, is dominantly limestone and shalej across the Ohio River in Lewis, Carter, and E lliott counties, Ken­ tucky, the formation consists mostly of dolomite and shale. As the

Brassfield formation is traced westward from Licking County into

Union and Logan counties, Ohio, and then into Jay County, Indiana, the overlying Cabot Head shale thins and disappears. Lower Niagaran medium-grained, gray or light brown dolomite rests upon similar dolomite that is probably Brassfield, The contact is generally placed above beds containing chert and glauconite, and is sometimes difficult to p ic k .

The eastern lim it of the Brassfield occurs in western West

Virginia. The Arrington well on Plate II shows a thin tongue of the lower part of this formation at a depth of U510 feet. In a ll direc­

tions the Brassfield or its equivalent extends beyond the area of

investigation except over part of the Cincinnati arch and in south­ eastern Indiana, where it is missing as a result of erosion.

According to Freeman (1951), the Brassfield seas spread westward from

Ohio and Kentucky into the Ozarks and at least as far south as

v'.'- northern Alabama and M ississippi.

In Ohio the maximum thickness of the outcropping section is approximately 58 feet near Jacksonville in Adams County, according to

Hopkins (195U, p. 89). To the east in the subsurface of Jackson

County the formation attains a thickness of 70 feet in the Grover well

southward in Kentucky the Stamper well in Carter County shows UU feet 18 of Brassfield. (See Plate III.) Northward from Hopkins’ measured section, the formation is 55 feet thick in the Snyder well in Union

County; westward from the Snyder well across the Ohio-Indiana state line this formation is still approximately 50 feet thick in Jay

County. Further west in Howard County, Indiana, the Brassfield car­ bonates thin to less than 30 feet in the Indiana Geological Survey d rill hole no. 72 at Kokomo (Shaver, 1961, p. 13). Some of the

Indiana thicknesses are shown on Figure 8.

The Brassfield formation rests with apparent conformity on redbeds of Ordovician age which comprise the Juniata formation in parts of eastern Ohio.. In western Ohio the Brassfield lies on the gray and greenish-gray thin-bedded limestone and shale of the Richmond

Group, which is Interpreted as a facies of the redbeds. Freeman (1953, pi, 9) shows three major facies of the Richmond Group southeastward from the crest of the Cincinnati arch: (1) gray limestone and shale,

(2) green argillaceous dolomites which become siltier to the east, changing to red silty shales, and finally (3) red silts and red sand­ stones that form the elastics of the Juniata formation.

Kaufmann (196U) n otes evidence o f an unconform ity between the Brassfield and upper Ordovician in Adams County, Ohio. An uncon­ formity is also indicated between the Silurian and Ordovician in an area where the Brassfield is missing and the Osgood rests directly on

Richmond strata. The area is surrounded by Brassfield beds containing pebbles of the underlying very fine-grained Richmond limestone. This situation was noted by Foerste (190U, p. 328) in Ripley, Jennings, and Decatur Counties, southeastern Indiana. The Brassfield-Qrdovician 19 contact may therefore be described as conformable in the basin, but unconformable at various localities on the flanks of the Cincinnati arch .

According to Ehlers and Kesling (1962, p. 7), the Brassfield formation of Indiana, southern Ohio, Kentucky, and states to the south correlates with the Manitoulin dolomite of Michigan and Ontario, the

Becsie formation on Anticosti Island, the lower Mayville dolomite of

Wisconsin, and the lower part of the Power Glen formation of western

New York. On the basis of lithology and stratigraphic position, the

Brassfield of Ohio is equivalent to the Manitoulin of Ontario. All the above-named formations, along with the Kankakee limestone of northern Illinois and the Sexton Creek limestone in southern Illin ois, lie within the Coelo3pira planoconvexa-Atrypa laticorrugata sone according to Ehlers and Kesling.

Tuscarora Formation

The Tuscarora formation was named by Darton (1696) for sand­

stone exposed on Tuscarora Mountain, Pennsylvania. It consists of massive medium- to coarse-grained white sandstone, with a few thin

shales in the upper part. The nearly pure rounded quartz sand is

cemented by silica into usually hard compact beds. The descriptive

terra subquartzite can be applied to most of the Tuscarora.

Subsurface strata are similar to outcropping beds except

that the thin shales are difficult to distinguish from "caving" in * the well cuttings. In this respect the gamma-ray-neutron logs are

h e lp fu l. 20

The thickness of this formation generally ranges between 60 and 200 feet. These beds thin southward on the outcrop along the

Wills Mountain anticline and related structures to about 100 feet in

Mercer and Monroe counties in southeastern West Virginia. The formation is approximately 200 feet thick in northeastern West

Virginia, and reaches 380 feet in the vicinity of Cumberland, Mary­

land, and U85 feet on the Nittany arch of central Pennsylvania. The

Tuscarora and its equivalents occur in parts of eastern Ohio, Penn­

sylvania, West Virginia, Virginia, Maryland, and eastern Tennessee, and are reported in northwestern Alabama and Georgia.

The thickness of the Tuscarora in the subsurface corresponds

roughly to that on the outcrop. The formation thins westward from more than 500 feet in Hardy County, northeastern West Virginia, to

125 feet at the Sand H ills well, Wood County, in the western part of .

th e s t a t e .

The Tuscarora is overlain by the Rose H ill and underlain by

the Juniata formations. Both contacts are believed conformable, as

indicated by their gradational nature. Where the lowest beds of the

Tuscarora are red-stained, the contact between it and the red sand­

stones and silty shales of the Juniata is difficult to pick. The

Tuscarora-Rose H ill contact is distinct in West Virginia, except where

somewhat friable basal "Clinton sand" is present. In this case the

contact is difficult to detect; on the outcrop it is generally placed

where the dense unfossiliferous Tuscarora sandstone is overlain by

thin-bedded sandstones with shale partings which often contain the

typical Rose H ill fo ssil Stegerhynchus neglectum. Woodward (1 9 h l, p. 1 5 1 ) accepts the Tuscarora formation in

West Virginia as basal Silurian, He believes these beds to be wholly equivalent to the Clinch in southwestern Virginia and Tennessee,

Woodward says th a t probably the B r a s s fie ld lim esto n e o f Ohio and Ken­ tucky occurs at this general stratigraphic position. The relations shown on Plates I and II support this equivalent position. As noted earlier, Chen (196U, p. 6) considers the Juniata and underlying

Oswego formations as basal Silurian in West Virginia.

Except for two obscure markings, Arthrophycus and Scolithus verticalis, the Tuscarora is without known fossils. Its age assign­ ment is based on stratigraphic position. The Brassfield formation of

Ohio and Kentucky and the Rockwood formation of eastern Tennessee appear to be equivalent. It is the fauna of these formations and of the overlying Rose H ill that indicates correlation of the Tuscarora with the Medina formations of western New York.

Cabot Head Formation

The term Cabot Head was first applied by Grabau in 1913 to the strata exposed at the northeastern tip of Bruce Peninsula in

Ontario. The strata referred to have subsequently been interpreted in various ways, most recently by Bolton (1957^ p. 16), who states

that lithologic character is a more reliable criterion than occurrence of the bryozoan Helopora fragilis, which is found also in the Clinton

Group, On this basis only the green and reddish shales between the

Manitoulin and Dyer Bay dolomites at the type locality constitute the

Cabot Head form ation . 22

Tha Haff w ell in Sandusky County, northwestern Ohio, penetrates

30+ feet of Cabot Head strata. These shales can be traced southward in the Ohio subsurface through Wyandot and Marion counties into the green shales that overlie the Brassfield in the Martin well in Licking

County and in other wells shown on the cross-sections. In southern

Ohio the Morrow and Buckeye w ells, Milton Township, Jackson County show a thin development (£ to 10 feet) of "Clinton sands'1 in the

Cabot Head s h a le .

The Cabot Head sh a le a tta in s a th ick n ess o f 7U f e e t a t the type section; southeastward near Hamilton, Ontario, the formation is

3U feet thick; and further east into western New York it thins and is replaced by the sandstones and shales of the Grimsby formation. In southern Ohio the formation ranges between a feather edge and approx­ imately £0 feet. The Cabot Head is from 75 to 100 feet thick in the northern peninsula of Michigan according to Ehlers and Kesling (1957,

P. 2 ) .

Tha Cabpt Head is disconformably overlain by various carbonate

strata in most of Ohio and Ontario. The overlying formation is the

Oldham in southern Ohio; the Dayton in parts of southwestern Ohio;

thin undifferentiated Clinton carbonates in northern Ohio; and in parts of eastern Ohio the shale and sandstone of the lower Rose H ill

formation. In Ontario the lower contact is everywhere gradational with the top of the Manitoulin and in Ohio this contact is gradational

or intertongues with the top of the Brassfield.

The fauna of the Cabot Head shows sim ilarities with the under­

lying Brassfield-Manitoulin. Although not limited to this formation 23 or the Brassfield-Manitoulin carbonates, the bryozoan Helopora fragilis is abundant in both the shales and hard calcareous beds uithin the shales.

Plum Creek clay. In Kentucky the stratigraphic position of the Cabot Head i s occupied by th e Plum Creek form ation, named by

Foerste in 1906. This is a clay shale with a little interbedded lim esto n e , named from s tr a ta exposed along Plum Creek, 3 m ile s south­ west of Clay City in Powell County, Kentucky. The formation apparently loses identity in outcrops south of Powell County and north of Clark County, Kentucky, where limestones become more common.

The thickness of the Plum Creek is normally about $ f e e t in

Madison County, Kentucky, and in surrounding outcrop areas. Approx­ imately 22 feet of strata in the Stamper well, shown on Plate III are referred to this formation. This well is located in Carter County,

Kentucky, northeast of the outcrop. The limited outcrop thickness and occurrence of the Plum Creek, compared to the greater thickness and wider distribution of the Cabot Head formation, and the more general acceptance of the latter name causes the writer to favor the

name Cabot Head for shale strata occupying the stratigraphic position between the Brassfield and the overlying Clinton carbonates in the

Ohio subsurface. Typical Plum Creek is unfossiliferous, but sparse

fauna in its northern extension are related to the underlying Brass­

field fauna. This fact caused Foerste (1931, p. 186) to refer the

Plum Creek shale to the Medinan. 2U

Stratigraphic Relations within tha Medina Group

Tha B r a s s fie ld form ation and tha o v erly in g Cabot Head sh a le are the most widespread of a ll the Silurian formations described in

this report, Brassfield strata were examined in the type locality in

Madison County, Kentucky. Similar beds identified in well cuttings were traced from Carter County in northeastern Kentucky to the vicinity of Lake Erie in Sandusky County, Ohio, where they occupy the

position of the Manitoulin dolomite just across the lake in Ontario.

The overlying Cabot Head shale in the Lake Erie area can be traced

southward along th e same ro u te in to the Plum Creek c la y in C arter

County, Kentucky. Figures U and 10 show that the upper part of the

Brassfield, which intertongues with the lower beds of the Cabot Head,

is replaced by shales to the north and in the process loses the

hematite zones and the characteristic color generally associated with

the upper beds. The massive lower Brassfield that continues north­

ward is continuous with the Manitoulin formation of southern Ontario.

Eastward both the Brassfield and Cabot Head formations change

to silty and sandy facies. Both formations intertongue with the

”Cli:ton sands" and the Tuscarora sandstone of eastern Ohio, Kentucky,

and West Virginia. These changes can be observed by a combined

analysis of well cuttings and gamma-ray-neutron logs which support an

equivalent stratigraphic position. Plate II shows these relations.

Well cuttings from south-central Ohio show grains of white quartzitic

sandstone, containing brownish-black and orange-red spots, interspersed

within the Brassfield carbonates. These distinctive sand grains are

* 2* prominent in certain "Clinton”-Tuscarora strata, but are found here and there in the basal formations of the overlying Clinton Group in eastern Ohio and West Virginia also.

Westward into Indiana the Brassfield continues as a recog­ nizable formation, whereas the Cabot Head is absent in north-central

Indiana.

C linton Group

The Clinton Group has its type locality at Clinton, New York, where, according to Fisher (1 9$9), it consists of quartz-pebble con­ glomerate, silty green and gray shale, thin hematites, non-silty platy green shale, and fine-textured impure sandstone. Toward the west and southwest these rocks merge into calcareous shale, limestone, and a few thin sandstones. In western Ohio the silty and sandy residues in the carbonate strata indicate the western-most lim its of the coarser elastics.

The Clinton Group in south-central Ohio includes those beds between the Cabot Head shale and the Lilley formation. Figure $

shows the lower part of the group is absent from most outcrop areas

in western Ohio. The exception is near Lawshe, Adams County. In

West Virginia a ll beds between the Tuscarora and McKenzie formations

comprise the Clinton Group, and in north-central Indiana this group

consists of the beds between the Brassfield and the Liston Creek. In northeastern Kentucky the beds are similar to those in south-central

Ohio except that the Waco and Plum Creek formations occupy the

stratigraphic positions held by the Dayton and Cabot Head formations, respectively, in Ohio. CLINTON CROUP UNIUlKoJi>OLOMIT^ \ f V S M l K |TT

EINL TAIRPI RLTOS O TE LNO GROUP CLINTON THE FOR RELATIONS STRATIGRAPHIC REGIONAL IUE 5 FIGURE rrm FO R M A T IO N S ARC N O T DRAWN DRAWN T O N ARC S N IO T A M R FO L. O H - IM4 M I - TH A V HOR . .L A O AY RIA SCALE L A C S ERTICAL V ANY TO ZONTAL A T N O IZ R O H E L A C S 'EM 27

Oldham Formation •

The Oldham form ation was named by F o erste in 1906 a f te r a town in east-central Kentucky. The best exposures are reported to occur in a railroad cut between Brassfield and Panola in Madison

County, Kentucky. The Oldham consists of thin- to medium-bedded fine- to coarse-grained limestone with interbedded blue-green shales.

Although the Oldham is dominantly gray or brownish-gray at the out­ crop, some of the thin beds show a variation in color and lithology that resemble the upper part of the Brassfield.

The Oldham form ation can be traced from southw estern Ohio

(Figure 6) eastward in the subsurface into the lower dolomites of the

Rose H ill formation at the Sand H ills well in Wood County, West

Virginia. This well is shown on Plate I. The Oldham formation is absent toward the west in Highland County, Ohio, where the Dayton rests unconformably on Brassfield beds, and in north-central Indiana where lower Niagaran rocks that do not resemble Oldham rest on Brass­ field. The writer believes that color variation in the upper thin- bedded Oldham strata, and the unwarranted assumption that a ll hematite zones belong in the Brassfield, have resulted in misidentification of

Oldham as Brassfield in the subsurface. Carbonate beds of uniform th ick n ess above the Plum Creek-Cabot Head sh a le may be tra ced north­ ward from the Stamper well in Carter County, Kentucky, to the M iller well in Pike County or the Grover well in Jackson County, Ohio. The equivalence of these strata to the Oldham of Kentucky is based on lithology, thickness and stratigraphic position. See Plates II and III. 28

MILLER WELL SE C T IO N • • mat SECTION 20 fI m M czz

RASE o r PATTON FORMATION •It

l u l r e o r u d

•31 run •45

KAUFM ANN ( I M 4 , P. I I 5 - I M )

■ ■■ r~ ' ■ t -0 HIOHLAND CO. / X ' l l l L L E R »••• _ _• ------y X WELL KAUFM A NN

l o c . * \ / , ; . . F I R E CO. < ! * ( ♦ , P. 1 (1 -1 1 2 ) 0 i L O C . 2 0 1

A D A M S C O . j

1 0 -1

I / /I DOLOMITE fX H COVERED HI -1001 8 . ^ M. 1 .7 1 || |1 LIMESTONE | +• | HEMATITE

■ M M M L lM C lT O M t r l A T 1 1* 1 I 0 THIN SHALE 1 ------i SH A L E NO HONIZONTAL SCALE -1010

CROSS SECTION SHOWING OLDHAM-BRASSFIELD

> j-«•RASSFIELD R A l / 1 00DOWN TO RELATIONSHIP IN ADAMS 8 PIKE COUNTIES 080 I 1 '

Cross-section showing Gldham-Brassfield relations Figure 6 29

Tha formation is over Hi feet thick near Panola, Madison

County, Kentucky, but is generally between 10 and 11 feet thick at the outcrop in tha surrounding area. It is approximately 12 feat thick in the Stamper w ell, Carter County, Kentucky, and maintains this thickness northward into Jackson County, Ohio, along the dapositional strike.

In the type locality of east-central Kentucky, the Oldham limestone is underlain by the Plum Creek clay and overlain by the

Lulbegrud clay. This same relationship is believed to exist at outcrops near West Union, Adams County, Ohio, and in the subsurface of south-central Ohio. One of the reasons that the Oldham has not been found previously in Ohio is that it cannot be identified with certainty at outcrops between Bath County, Kentucky, and Adams County,

Ohio. North of Owingsville, Bath County, the large number of thin limestones in the Plum Creek clay make the Oldham-Plum Creek contact difficult to determine. Foerste believed the Oldham limestone dis­ appears northward before reaching Fleming County, Kentucky. He based this conclusion partly on the absence of the Stricklandinia norwoodi zone, which occurs at the top of the Oldham in the Brassfield,

Indian Fields, Clay City, and Irvine areas, Kentucky, near the type l o c a l i t y .

Foerste (1935, P* 132, 190) found a single valve of the ostracod Zygobolba rectangula in the Oldham limestone U miles east of

Owingsville, Kentucky. This species is characteristic of the middle part of the Lower Clinton at Cumberland, Maryland. The characteristic fossil of the Oldham in east-central Kentucky is Stricklandinia 30 !* norwoodi, a specias of brachiopod that Foarsta (1935, p. 190) found elsewhere only at Birmingham, Alabama, where it occurs in the

Stricklandinia zone, a short distance beneath the Pentamerus zone.

The latter zone occurs also in the Wolcott limestone of New York.

This roundabout correlation suggests that the Oldham is equivalent to the Lower Clinton of New York, but beneath the level of the

W olcott.

Lulbegrud Clay

Approximately 13 feet of unfossiliferous "blue" shale are exposed along Lulhegrud Creek where it forms the boundary between

Powell and Clark Counties, Kentucky. Foerste (1906, p. $0) named these beds and considered them part of the Alger formation, which was defined as including a ll strata between the Oldham and Bisher formations. Foerste later (1923, p. U) defined the Alger in Ohio as comprising the shale beds between the Dayton and Bisher formations, thus excluding the Lulbegrud clay. As this clay has been tentatively identified on the outcrop in southern Adams County, Ohio, it seems best to dissociate it from the Alger and to consider it a separate form ation .

The outcrop thickness of the Lulbegrud ranges from 6 feet near Crab Orchard, Lincoln County, Kentucky, to more than 1U feet north of Irvine, E still County, Kentucky, In the Anderson well,

Pike County, Ohio, and in the Grover w ell, Jackson County, thicknesses of 9 and 15 feet, respectively, are assigned to this clay shale. 31

The northern extent and differentiation of the Lulbegrud is determined to a large degree by the northern extension of the over- lying Dayton-Waco formation. Without the occurrence of these over- lying carbonate strata, the Lulbegrud cannot be differentiated from the Estill-Alger shales. Similarly, where the underlying Oldham or its equivalent is missing, the Lulbegrud cannot be differentiated from th e Plum Creek c la y . The age o f t h is u n fo s s ilife r o u s c la y i s assigned solely on its position between beds of reported Clinton age.

Dayton Formation

Orton (1871, p. 297-300) named strata exposed near Dayton,

Montgomery County, Ohio, the "Dayton Stone." At the outcrop it con­ sists typically of 2 to 7 feet of gray to greenish-gray fine-grained usually dense, hard limestone.

Well cuttings indicate that the subsurface Dayton consists of % a very light gray to greenish-gray fine-grained dense limestone or dolomite, with the latter predominant. Occasionally some red granular dolomite is interbedded with typical Dayton. In certain localities, especially near the eastern lim its of the formation, the bads are fine- to medium-grained and tan to light brown with occasional green mottling. Glauconite pellets in the overlying basal E still shale, occasional glauconite in the Dayton, the distinctive greenish-gray tinge, and the dense fine-grained texture are most useful in tracing the Dayton in the subsurface.

Well data show that the Dayton continues northeast through

Coshocton County, Ohio. To the east in the Arrington well, Mason 32

County, and in the Sand Hills well, Wood County, West Virginia, the formational thickness is generally maintained although most'of the dolomite changes to dolomitic siltstone with some glauconite. In the latter well the writer assigns the 7510-7605 interval given by

Shearrow (1957, p. UO). Southward in Kentucky the Dayton equivalent is believed to be the Waco limestone and shale, exposed in E still and adjacent counties. The formation is probably not present in the sub­ surface of northwestern Ohio, since the distinctive Dayton lithology

(except for a rare trace) is absent from wells in Hardin, Marion,

Wyandot, and part of Union cou n ties.

The Dayton is exposed as far north as Piqua in Miami County,

Ohio, where it attains a thickness of nearly 12 feet. It is com­ monly 3 to U f e e t th ick in Highland County (Bowman, 1956, p. 1 9 ).

According to Foerste (1931, P. 172) and others, the Dayton reaches

Lewis County, Kentucky. Approximately 8 feet of Dayton (?) strata have been reported as far west as Andersonville in Franklin County,

Indiana.

The relatively uniform thickness of the outcropping Dayton formation continues into the subsurface. The formation maintains its thickness (between 5 and 15 feet) both along its strike and eastward into the deeper parts of the basin. An exception occurs in the

Martin well in LLeking County (Plate III), where an overlying argillaceous basal dolomite in the Clinton shale increases the apparent thickness of the Dayton section. This argillaceous dolomite is considered true Dayton by some geologists, who note that the 33

Dayton tends to become thinner-bedded and more shaly toward the top,

northward and westward from central Greene County, Ohio.

The Dayton formation appears to be conformably overlain by

the S still shale in the area of investigation. Recent investigations by Rexroad et al. (in preparation) indicate a distinct faunal gap between the two formations in Adams County, Ohio. At outcrops in

northern Adams, Clinton, and Highland counties the Dayton rests dis-

conformably on the Brassfield. Eastward in the subsurface beds of

shale and carbonate rocks intervene between the two formations.

These intervening strata occupy the position of the Plum Creek,

Oldham, and Lulbegrud formations, which are found between the Brass­

field and Waco formations in Kentucky. The writer has not been able

to differentiate the Dayton from other Niagaran formations in cuttings

from Indiana w ells.

Foerste (1906, p. $0) at first believed the Oldham limestone

of Kentucky to be equivalent to the Dayton formation in Ohio, but

later changed his opinion (193$, p. 133). The current opinion is that

the Waco of Kentucky is equivalent to the Dayton formation in Ohio.

Supporting evidence includes stratigraphic position, thickness of

beds, and overlying and underlying strata. Rock characteristics are

also helpful in showing equivalence.

Waco formation. In Kentucky the stratigraphic position of the

Dayton is occupied by the Waco limestone. Foerste (1906, p. £3)

named 10 f e e t o f c la y and th in lim esto n es exposed \ m ile e a s t o f Waco,

Madison County, Kentucky, the Waco limestone. Rock cuttings from the

3810-1*6 interval in the Stamper well, Carter County, are indicative 3U of tha Waco formation, although these cuttings are dolomite rather than limestone.

This formation was traced by Foerste over an area of 300 square miles between Irvine, Clay City, Indian Fields, and Brass­ field, Kentucky, He found the thickness to be about 10 or 11 feet.

This is identical with the subsurface thicknesses obtained from well records by the writer. Beyond the area mentioned, the Waco becomes sparsely fossiliferous and Foerste was not able to trace it north of

Indian Fields or south of Berea, Kentucky,

Abundant fossils were found in both limestone and clay of the

Waco e:xposed along the road passing E still Springs north of Irvine,

Kentucky. Corals predominate and bryozoans are numerous, but other fossils are comparatively scarce. The contained fauna is distinct from the Clinton fauna at New York, so that correlation is -based on position below the overlying Estill-Alger shale. The underlying

Lulbegrud clay is unfossiliferous, but the next lower formation, the

Oldham, i s o f C linton age.

E still Formation

The name Alger was taken from a small town in east-central

Kentucky and applied by Foerste in 1906 to that part of the Crab .

Orchard formation that is composed of Lulbegrud snale, Waco limestone, and E s t i l l c la y , l'n th e same year (1906, p . $9) he designated E still

Springs north of Irvine as the type locality for £6 feet of non- fossiliferous blue shales named the E still clay, defined as that part of the Alger that overlies the Waco in Kentucky. In 1923 (p. U) Foerste, believing the Dayton and Oldham to be equivalent, used the name Alger for the stratigraphic interval between the Dayton and

Bisher formations in Ohio. At present tha Waco and Dayton are be­ lieved to be equivalent. The name Alger formation therefore refers to different intervals in Ohio and Kentucky. Foerste's definition of the Alger for Ohio in 1923 makes it equal to the E still clay as defined in Kentucky, although he did not intend it that way. Under the circumstances it seems preferable to use the name E still form ation.

The E still is described as a "blue" shale near its type locality in Kentucky, and as a greenish-gray clay shale containing dolomite stringers in surface exposures in southwestern Ohio. In sample cuttings from wells in E lliott, Carter, and Lewis counties,

Kentucky, the E still contains about equal amounts of red-brown and gray-green shale. In well cuttings from Ohio, it varies from gray or gray-green at the top to a mixture of brown, red-brown, and gray- green throughout the remainder of the formation. In both Ohio and

Kentucky, thin interbedded dolomitic siltstones and dolomites are commonly concentrated near the top and bottom of the E still. Some of these interbeds are too thin to be shown by the minimum 5-foot interval used on the cross-sections; where 5-foot intervals of dolomite and siltstone are shown, thin interbeds of shale are sometimes present. Thickness, extent, and relations with other formations are discussed in the following section on the Rose H ill formation. Most of the Rose Hill is stratigraphically continuous with the E still clay. \ 36

Rose H ill formation. This name was given to strata exposed . at Rose H ill, Cumberland, Maryland, by‘Swartz (1923, p. 280). The

Rose H ill comprises a ll beds between the top of the Tuscarora and the bottom of the Keefer sandstone in Maryland. These beds consist of green or red siltstones and sandstones. Subordinate amounts of ca lca reo u s str a ta may a ls o be p r e se n t. The form ation i s predom inantly shale, although one-third of the total thickness, particularly in the lower part, may be sandstone and siltstone. In the Sand H ills well,

Wood County, West Virginia, thin dolomite stringers, probably equivalent to the Dayton and Oldham formations of Ohio, comprise part of the lower Rose H ill.

The Rose H ill sandstones in the surface and subsurface can be classified into three general types. A very fine sandstone or silt- stone, green, gray, or red-brown, often thin-bedded and somewhat shaly, micaceous, and friable, generally occurs interbedded with s h a le . A second type o f sand ston e, which i s conspicuous but uncommon, is a deep red medium-grained hematitic somewhat angular quartz sand­ s to n e . The hem atite i s d escribed as o o l i t i c , b u t in some in sta n c e s the term pelletal is more appropriate. When present these beds may occur at more than one stratigraphic position, as in the Damron well in Greenbrier County, West Virginia. The name Cresaptown Iron sand­ stone has been applied on the outcrop to one of these beds that con­ tains approximately 20 percent iron. In some wells in western West

Virginia, thin carbonate stringers with pelletal hematite occupy the position of the Oldham. The third type of sandstone is white to light gray with occasional orange staining, and often bears a 37 striking resemblance to Tuscarora subquartzites. The cement may be partly dolomitic or siliceous. This sand is either partly friable or tight and hard, so that individual grains are nearly indistin­ guishable. The latter variety causes boundary difficulties when it occurs near the base of the Rose H ill, where it is gradational with the underlying Tuscarora. This third type of Rose H ill sandstone also resembles some of the "Clinton sands" of Ohio. The latter are generally accepted as equivalent to the Tuscarora of West Virginia and the Medina of New York.

The term Cacapon merits discussion, since some geologists refer to the lower Rose H ill sandstones, siltstones, and shales by this name. The term was used by Darton and Taff (I896) in referring to a conspicuous deep-red medium-grained hematitic sandstone, con­ taining about 20 percent iron, in the Rose H ill formation. The

Cacapon division of the Rose H ill as commonly used by subsurface geologists includes the predominantly sandy lower part of the Rose

H ill beginning with beds that overlie the white "Clinton" or Tuscarora and continuing upward in the section through iron-stained and common

sandstone and shale into the uppermost hematitic sandstone. The

Cacapon division of the Rose H ill occupies only a very general strati­ graphic position, since it is apparent that hematitic or iron-stained

sandstones are not restricted to a particular interval or even to the

same form ation .

Excluding the Cacapon division just described, the Rose H ill

formation of Pennsylvania, West Virginia, and Maryland resembles and is stratigraphically continuous with the E still formation of Ohio and Kentucky. The term Estill-Rose H ill is used in the remainder of this section in describing properties that these beds share as a continuous unit.

The Estill-Rose H ill formation is present throughout the area of investigation, except on the Cincinnati-Findlay arch where these strata have either been removed by erosion or are represented by a carbonate facies. The dominantly shale strata thicken eastward into the deeper part of the Appalachian basin. The thickness ranges from a feather edge in central Ohio to almost 700 feet in the sub­ surface of Preston County, West Virginia. Swartz (1923, p. 28) rep orts $$2 feet of Rose H ill beds near Cumberland, Maryland. Most wells in central and eastern Ohio investigated by the writer show between 80 and 160 feet of shale, whereas the West Virginia wells generally indicate between 200 and i|00 feet. To the south in Martin

County, Kentucky, the James well penetrated 220 feet of Estill-Rose

Hill shale. Eastward thickening indicates a possible source in the

Blue Ridge area of Virginia, Maryland, and perhaps a northern ex­ tension of this area into Pennsylvania.

In south-central Ohio, and in Lewis and Carter Counties, northeastern Kentucky, the Estill-Rose H ill formation is overlain by the Bisher carbonates and underlain by the Layton-Waco formations.

Further south in E lliott County, Kentucky, the lower sandy portion of the Bisher becomes the drillers' "Big Six" producing sand which here overlies the Estill-Rose H ill, In eastern Ohio the lower portion of the driller's "Clinton" shale is equivalent to tha Estill-Rose Hill formation. In this area the upper Estill-Rose Hill contact is placed 3 9 beneath thin very silty or fine sandy carbonate beds in the Clinton shale which can be traced into the Keefer of West Virginia* the lower contact is placed at the top of the driller's "Clinton sands."

Further east in West Virginia and haryland, the Hose H ill formation is overlain by the Keefer sandstone and underlain by the Tuscarora sandstone.

The contact of the E s t i l l w ith the underlying Dayton-Waco formation in Ohio and Kentucky has until recently been considered conformable. Rexroad and others (forthcoming paper) have encountered a faunal gap at the approximate position of glauconitic beds near the base of the E still. The lower contact of the Estill-Rose Hill with the Tuscarora formation in West Virginia has already been described.

Although it appears possible to trace the Estill-Rose Hill of Ohio and Kentucky into the clay at the top of the Osgood in south­ eastern Indiana, Foerste (1935, p. 129) indicates that faunal content suggests a younger age for the Osgood. He explains this faunal d ifferen ce by a p ossib le invasion of Osgood fauna from the south, whereas the Rose H ill-E still (.alger-Rfbolt faunal zone) had its affiliation in an eastern source. Bowman (1956, p. 32) writes that the upper Alger (Estill-Rose Hill) beds of Highland County are probably tim e-equivalent to the Osgood formation of Greene County,

Ohio. Woodward (19U l, p. 91) agrees with bwartz (1923, p. 195) in correlating the Rose H ill of haryland and West Virginia with the pre-

Rochester Clinton of Hew York on faunal evidence. Osgood shale. The name Osgood shale was given by Foerste

(1897* P* 227-229) to a series of interbedded limestones and shales exposed near Osgood, Ripley County, southeastern Indiana. In Indiana the formation consists of two limestones and two shales, which Foerste called the lower and upper Osgood limestones and the lower and upper

Osgood shales. He correlated the lower Osgood limestone, the lowest of these four units, with the Dayton limestone of Ohio. The section at Derbyshire Falls near Laurel, Indiana, (Prosser, 1916, p. 362) illustrates these four units:

U. Buff compact limestone 8'1 3. Blue soft clay shale l’6ir 2. Light gray shaly limestone 1. Light gray, even bedded compact limestone- Dayton(?) 6 ,U"

The above section may be compared with the section at the

Lewisburg quarry, one mile northwest of Lewisburg, Preble County,

Ohio, This Outcrop is approximately 1|0 miles northeast of the one at

Derbyshire Falls, Busch (1939, P. 65) records the same measured section that Foerste had measured at an earlier date:

Light gray clay.shale u . Shaly limestone 3 . Light gray clay shale 3" 2 , Shaly limestone $'• 1 . Light gray clay shale 2'6''

A comparison o f the two s e c tio n s shows th a t the number o f shale and limestone units do not correspond whether or not the Dayton

(?) beds are excluded from the Derbyshire Falls section. The units listed above show even less resemblance to the Osgood units at Bryan

State Park near fellow Springs, Greene County, Ohio, which is 35 miles due east of Lewisburg, At the latter locality the formation consists of an expanded section of blue-gray clay shale with inter­ bedded thin- to medium-bedded dolomite. The thickness and pre­ dominance of blue-gray shale in the Yellow Springs area more nearly resemble the Estill-Rose H ill formation of southwestern Ohio,

Kentucky, and West Virginia.

According to Busch (1939, P* 68), the thick Osgood shale of

Clark and Greene counties is commonly regarded as the northward extension of the Alger (E still) shale of Highland and Adams counties,

Ohio* The writer concurs with this interpretation.

Attempts to trace the Osgood between Laurel, Indiana, and

Yellow Springs, Ohio in the subsurface Were unsuccessful because the few available wells show sample gaps near the surface.

The Osgood formation thins westward from nearly 2$ f e e t a t

Bryan State Park to U feet at the Lewisburg quarry and to 2 feet 6 inches (Dayton excluded) near Laurel, Indiana. The formation thickens southward from Laurel to about 30 feet in Jefferson County, Kentucky.

Northward from Laurel the Osgood thins and disappears along an approximate east-west line through the middle of Randolph County,

Indiana, and extending eastward along the northern edge of Miami

County, Ohio. Examination of cuttings from the Resur well in Jay

County, Indiana, indicates the Osgood shale is not present.

The upper and lower contacts of the Osgood formation in west- central Ohio are reported to be conformable. The formation is over- lain by the Laurel limestone and underlain by the Dayton limestone.

The only fossils recorded from the Osgood of west-central

Ohio were collected by Foerste at Rocky Point, three miles northeast of Dayton, Ohio. They are a ll long-ranging Niagaran forms that are non-diagnostic of the Osgood and useless for correlation. Baasler identified 33 species of bryoaoa from the Osgood of southeastern

Indiana and adjacent parts of Kentucky, a ll of which occur among the

80 species that he identified from the Rochester shale of New York

(1906, p . 5). Busch (1939, p. 69) correlates similar strata in west-central Ohio with the type Osgood of southeastern Indiana on

the basis of lithology and stratigraphic relations. On this basis

the Osgood formation of Ohio correlates indirectly with the Rochester of New York.

The Osgood is important for several reasons: (1) It is one

of only three or four Silurian formations previously identified on both sides of the Cincinnati arch; (2) the westward and northward

thinning of the shale units away from the source areas of the E still-

Rose Hill formation affirms the probable stratigraphic continuity of

the Osgood with these formations; (3) the thin Osgood strata which

occur on the arch consist of almost equal thicknesses of limestone

and shale. The question arises: Is the absence of Osgood shale north

of Randolph County, Indiana, and Miami County, Ohio, due to facies

change or was the shale deposited and later eroded along with the

overlying Bisher in this area as Rittenhouse suggests?

Bisher Formation *

The name Bisher was applied by Foerste (1917, p. 190) to the

lower of the two members of Orton's West Union formation exposed at a

locality just southeast of Hillsboro, Highland County, Ohio. In 1923 (p. 2I4.) Foerste raised the Bisher to formation rank and abandoned the term West Union. A 1935 redefinition consisted of shifting some shales into the upper part of the Bisher formation.

According to Bowman (1956, p. 35)* the Bisher consists of 2 four lithofacies in southern Ohio: silty carbonate, dolomitic shale,

Cryptothyrella carbonate, and limestone. One or more may be locally present, but the basal part of the Bisher is invariably the silty carbonate lithofacies. In southern Ohio the latter lithofacies com­ prises both the upper and lower parts of the Bisher although the

Cryptothyrella carbonate, dolomitic shale, and limestone lithofacies are sometimes interspersed within these beds. This fact led Bowman

(1961, p. 265) to conclude that the silty fine-grained even-textured distinctly bedded dolomite, in layers from a few inches to five feet in thickness, is the most characteristic lithologic expression of the Bisher in southern Ohio.

Three of the four lithofacies are identifiable in the sub­ surface. The Cryptothyrella carbonate can be recognized more easily when weathered. The dolomitic shale is dominant in well cuttings from central and east-central Ohio where it comprises the upper part of the driller's Clinton shale. Wells located in Fairfield, Licking,

Muskingum and Coshocton counties show this lithofacies to be a very

^ B o w m a n bases these lithofacies upon general lithologic types each of which was deposited in a distinctly different lithotope. He uses the term according to Moore's definition "to denote the collective characteristics of any sedimentary rock which furnishes a record of its depositional environment." A lithofacies therefore embraces the or­ ganic characteristics of a deposit as well as its lithologic aspect. argillaceous finely-granular dolomite rather than a dolomitic shale.

The silty carbonate is the most useful lithofacies for subsurface correlation in southern Ohio, because in most localities it is in contact with the basal beds of the overlying Lilley formation. In wells from Pike County, Ohio, to Mason County, West Virginia, the

top of the Bisher coincides with the upper lim its of carbonate strata

having a marked increase in silt or fine sand (Plate II). The dolo­ mitic shale lithofacies is dominant in an east-west belt through

central Ohio; the silty carbonate lithofacies is dominant in southern

Ohioj and the limestone lithofacies seems to be dominant in some western Ohio wells, which suggests that the latter may be partly

equivalent to the Laurel limestone which occurs at approximately the

same stratigraphic position. The Hopkins well in Fayette County,

Ohio, shows an alternation of beds composed of the silty carbonate

(dolomite) lithofacies and the limestone lithofacies. The writer believes the various lithofacies of the Bisher resulted from the

interaction of water depth above the irregular floor of the deposi­

tional basin and rate of clastic influx from clay and sand source

areas in West Virginia.

The Bisher crops out in Highland County, Ohio, where it is

23 to 8I4. feet thick according to Bowman (1961, p. 26$), It is also

exposed in Adams County and across the Ohio River in Fleming and

E still counties, Kentucky. Freeman (19^1, p. 12) traces the Bisher

into the driller's "Big Six" sand in the subsurface of Jackson,

Kentucky. The writer's studies reveal the Bisher to be present in

wells as far south as Magoffin and Martin counties, Kentucky, where the combined "Big Six"-Bisher thickness ranges from $0 to 70 feet.

The Bisher with thicknesses from U5 to 65 feet can be traced by- well cuttings from southern Ohio eastward into Mason County, West

Virginia (Plate II), Further east this interval is occupied by the

Keefer sandstone, and in northern West Virginia by the Keefer and the overlying Rochester shale. In Ohio the northern lim its of the Bisher were not determined, but approximately 10 feet of silty carbonate in the Haff well, Sandusky County, Ohio, are referred to the Bisher formation. In this well the entire Clinton is probably less than 25 feet thick. This fact and the fragmental intermixed condition of the sediments suggest erosion during late Clinton. The Eisher is gener­ ally believed to be confined to the eastern side of the Cincinnati arch, but silty residues from the Springfield formation along the

Greene-Clark County line in Ohio and from the Mississinewa shale of

Indiana indicate a possible westward extension of the Bisher form ation.

The contact between the Bisher and the underlying E3till is . conformable and is reported to be sharp and distinct at nearly all exposures. In the subsurface this is not always the case. In

Marion, Licking, Union, and parts of adjacent counties, much less silt is found in the dolomite residues. In this region the E still clay, which normally underlies the Bisher, Is absent either as a result of facies change or by erosion as Rittenhouse (1 9h9) p rop oses.

The Snyder well in Union County, Ohio, shows non-typical Bisher strata resting unconformably on the Dayton formation. U6

Paleontologic evidence based on ostracods supports a corre­ lation with the Rochester of New York. Foerste (1919, p. 369, 1931, p. 189, 190) lists species from Bisher strata in Clinton, Highland, and Adams counties, Ohio, and Lewis County, Kentucky. Eowman (1956, p . $1) states that the ostracods denoting a Rochester age were probably collected near the base of the Bisher, and are not neces­ sarily indicative of the age of the middle and upper parts of the form ation.

Laurel limestone. Twelve feet of limestone exposed near

Laurel, Franklin County, Indiana, were named by Foerste (I896, p.190) the Laurel limestone. On the basis of stratigraphic position and paleontology, Busch (1939, p. 75) correlated similar limestone beds in western Ohio with the Indiana type section.

In Ohio the formation consists of dolomitic limestone and dolomite, fine- to medium-grained dense, argillaceous in places, and thick-bedded at the outcrop. Limestone occupying the position of the Laurel occurs in the Snyder well, Union County, and in the

Hopkins well, Fayette County, but these strata could not be identi­ fied with certainty.

The Laurel thins eastward in Ohio from feet at New Paris to 15 feet at Lewisburg and 5 feet near Yellow Springs. In. Clark and Greene counties, it is overlain by the Massie shale; in Miami and Preble counties a sharp contact exists where the Euphemia is the overlying formation. The Laurel is underlain by the Osgood shale.

According to Busch (1939, p. 76) and Shaver (1961, p. 18), the Laurel is of Lower Niagaran or Rochester age. Recent reclassification of the Huntington in Indiana resulted in referring beds identified as Huntington at some outcrops to the Laurel. Per­ haps beds called Huntington in western Ohio are also equivalent to

the Laurel.

Massie Shale. The Massie is a thin fossiliferous shale U to

6 feet thick, which lies conformably between the Laurel limestone below and the Euphemia dolomite above in Greene and Clark counties,

Ohio. Esarey and Bieberman (19U8) correlate it with the Waldron

shale of Indiana on both lithologic and faunal evidence. The writer assigns it to the upper part of the Clinton Group and believes it 3 may be equivalent to part of the Bisher in Highland and Adams

c o u n tie s.

Euphemia dolomite. Rocks exposed in a quarry north of

Lewisburg, Preble County, Ohio, were named the Euphemia dolomite by

Foerste (1917, p. 187). These beds are gray medium-grained porous massive dolomite. Fresh exposures show blue-gray mottling. The

Euphemia is found at several places along the Niagaran outcrop from

Greene County westward to the Ohio-Indiana border, but it has not been traced outside Ohio. This formation cannot be differentiated

in well cuttings from carbonate beds above or below. The thickness

of the Euphemia ranges from 3 feet at New Paris to 11 feet at

Springfield.

^''Equivalence'1 or "equivalent" in this paper is used in a litho­ logic or stratigraphic sense. It is not synonymous with correlation which involves age relations based on paleontologic evidence. The Euphemia rests conformably on the Massie shale in Greene and Clark counties, and on the Laurel limestone in Miami, Montgomery, and Preble counties. It is overlain conformably by the Springfield dolomite. The fauna of the Euphemia has affinities with those of the overlying Springfield and Cedarville dolomites. According to Busch

(1939, p. 91) the Euphemia is Lockport in age. The writer believes this formation is equivalent to part of the Bisher formation and places it in the Clinton Group.

Springfield dolomite. Orton (1873, P. U67) named the rocks quarried for building stone near Springfield, Ohio, the Springfield dolomite. In 1917, Foerste divided these strata and renamed the lower part the Euphemia dolomite. The Springfield formation is a light gray generally fine-grained, thin- to medium-bedded dolomite.

Like the Euphemia, this formation cannot be differentiated with certainty in the subsurface from underlying and overlying carbonate beds. Outcrop thicknesses of the Springfield range from 6 to 16 feet.

Both the upper contact with the Cedarville and the lower one with the Euphemia are reported conformable. They are easily recog­ nizable on the outcrop because of the brick-like manner of weathering of the Springfield. Eusch (1939, p. 102) correlates the Springfield with the lower Lockport of New xork on faunal evidence. Butterman

(1961, p. £8) indicates that the Springfield has more coarse residue

(mostly quartz silt) than any of the Niagaran formations above or below it. On this evidence, and on stratigraphic position, the writer favors equivalence with the Bisher formation of southwestern Ohio. h9

Keefer Formation

Eastward from south-central Ohio, s ilt and fine sand become more abundant in the basal Bisher carbonate beds. This lowermost

Bisher is continuous with a widespread sandstone, known as the

Keefer, that overlies the Rose H ill shales in parts of eastern Ohio,

West Virginia, Maryland and Pennsylvania, It was named from Keefer

Mountain near Hancock, Maryland by Stose and Swartz (1912).

Commonly the Keefer is a dense fine-grained subangular to angular white to light gray or red-brown sandstone, which in places resembles the subquartzite of the Tuscarora. It generally has a calcareous cement and is partly shaly. The Keefer occurs in three northeast-southwest trending belts. Along the eastern belt, extending south from Harrisburg, Pennsylvania, through eastern Maryland into

Berkley, Morgan, Hampshire, and Hardy counties, West Virginia, the formation is a rather uniform massive gray sandstone. Along a western belt, from west-central Pennsylvania to Allegany County,

Maryland and Mineral, Grant, and Pendleton counties, West Virginia, the Keefer is coarser, somewhat friable, and more limy. It is along the latter outcrop that a bed of ferruginous sandstone at the top of the Keefer grades into oolitic hematite, called the Roberts iron ore.

The ore bed thins from approximately 2 feet in Maryland and Pennsyl­ vania to 6 inches in West Virginia, Along a median belt in Hampshire,

Hardy, Grant, and Pendleton counties, 'West Virginia the Keefer con­ sists of thin sandstones and sandy shales.

All the lithic characteristics described above can be found in the subsurface, although the lithology noted for the median belt 5o is prevalent in well cuttings examined by the writer. A thin hema­ tite bed is found to occur near the top of the Keefer in the Damron well, Greenbrier County, West Virginia, The thin seam of hematite found at the base of the Keefer in certain outcrops was not found in the few wells examined. Swartz (193U, P« 88, 118) places this lower hematite zone in the uppermost Rose H ill on paleontological evidence.

The Keefer is from 5 to 30 feet thick in West Virginia exr* posures. Well records generally show a range of 10 to 30 feet, al­ though the Keefer may locally range between a feather edge and 100 feet. The Keefer and its equivalent, the driller's "Big Six" sand, covers most of West Virginia, a part of eastern Kentucky and eastern

Ohio, and some areas in Pennsylvania, Maryland, and Virginia.

Where the Rochester shale overlies the Keefer at the outcrop,

the contact is sharp and clear-cut. The Rochester shale is present

in northeastern West Virginia but is absent from some of the south­

eastern counties. The writer was able to identify certain or probable Rochester in only a few wells. Where the Rochester is

absent and the basal part of the overlying McKenzie is composed of

sandy limestone, the upper contact of the Keefer is gradational and

is d ifficu lt to place, ' Westward near the Ohio-West Virginia border

the Keefer grades laterally into the sandy dolomite of the Bisher.

The Keefer sandstone is normally unfossiliferous. Its

limited fauna consists mostly of brachiopods (11 species), a few

trilobites (3 species), and rarely a pelecypod or eurypterid. The

fauna includes both Rose H ill and Rochester forms. Woodward (l?Ul,

p. 106), notes a preponderance of the latter, especially among commonly occurring species. He places both the Keefer and the

Rochester in the expanded Clinton Group of West Virginia. Because of its limited thickness, Swartz (1923, p. 32) considers the Keefer a member of the Rochester formation. The West Virginia Geological

Survey currently accepts the Keefer as a formation (Chen, 196U, p. 15).

Folk (1962, p. 573, fig. 12) proposes a partly contemporaneous origin for the Keefer sandstone and the Rochester shale in Morgan

County and part of northern West Virginia. The Keefer barrier bar developed and as deposition proceeded it gradually moved westward from the northeastern "panhandle11 of West Virginia isolating a large shallow lagoon to the east in which the fine clays and lime muds of the Rochester were deposited; because of impeded circulation they were black and rich in organic matter and pyrite. As the bar moved westward toward Ohio the sand supply dwindled and the sediment was cemented with calcite instead of quartz; the bar passed out of ex­ istence as it reached the Ohio-West Virginia state line thereby re­ moving the barrier to normal marine circulation in the Rochester lagoon. Subsequently the green shales and carbonates of the McKenzie formation were laid down.

The writer finds Folk’s proposal to be a rather ingenious explanation for northern West Virginia, but is not entirely adequate to explain the different lithofacies of the Bisher in Ohio. The dolomitic shale lithofacies is dominant in central Ohio and the silty carbonate lithofacies in southern Ohio. The silty carbonate and a sandy lithofacies ("Big Six" sand) occur in Kentucky. The following explanation (illustrated in Figure 7) is favored by the n o . I ) sb ( b u s

i r ’»v '■ * « ? bl < U. H ; % lA l J

1I V N

O Sf w

o o nt 3; (*-») fa* p t o i .- o *

Paleogeographic map of the Clinton

F igure 7 writer: In western West Virginia a sandy delta extended in a slightly northwesterly direction almost to the southeastern border, of Ohio. To the northeast lay a bay or lagoon in which waters were generally restricted. During times of delta maxima, currents moved sand northeastward to form bars which restricted the bay or lagoon of the type suggested by Folk where Rochester shale was accumulating.

At times the bay opened to normal marine circulation so that argillaceous matter was picked up and scattered westward in the dolomitic shale lithofacies of the Bisher in central Ohio. The growing delta provided the sands of the "Big Six" in Kentucky and the silty carbonate Bisher lithofacies in southern Ohio. During periods of less active clastic sedimentation the Cryptothyrella carbonate and the relatively pure limestone lithofacies were

deposited in southern Ohio.

Rochester Formation

Typical Rochester shale is absent from a ll the Ohio and western West Virginia wells investigated by the writer. However, the argillaceous matter found in the Bisher formation and the upper part of the Clinton shale in Ohio is believed to have the same source as

the Rochester of northeastern West Virginia. The Rochester formation of West Virginia, Pennsylvania, and Maryland is considered continuous with the gray calcareous Rochester shale of western New York, which was named by James Hall in 1838, from the city of Rochester where it

is exposed along the Genesee River. In the Appalachian region,

Woodward (I9J4I, P. 107) describes this formation as thin-bedded, fissile or platy gray to dark shales with thin dense fossiliferous blue-gray limestones. On the outcrop the soft calcareous shales weather rapidly.

The Rochester is present on the outcrop in the northeastern counties of West Virginia and in the subsurface of Randolph, Preston,

Harrison, and Hardy counties. Surface exposures average about 2$ feet in thickness, and deep wells generally show 20 to £0 feet of s tr a t a .

The Rochester shale rests with a distinct lithologic break on the underlying Keefer sandstone. The upper contact with the

McKenzie formation shows different degrees of gradation. The thin limestone and dark shale of both formations have certain sim ilarities in some areas; Folk (1962, p . £77) s ta t e s th a t in Morgan County green shale is characteristic of the McKenzie; Rochester shale is always dark brownish-gray to black. On the outcrop the boundary is placed between the Schallwienella elegans zone of the uppermost Rochester and the W hitfieldella marylandica zone at the base of the McKenzie.

In the Randolph County well, the upper Rochester and the lower

McKenzie both consist of dark gray silty and argillaceous limestone.

Here the contact is arbitrarily placed just above the unit showing an increase in argillaceous material as indicated by the gamma-ray- neutron log.

Woodward (19Ul, p. 112) mentions that the Rochester shale is one of the most fossiliferous formations of West Virginia. It con­ tains a larger number of species than any other Silurian formation

in th e s t a t e . The main fauna i s known as th e D repanellina c la r k i fauna. The essential equivalence of the Drepanellina clarki zone in the Rochester shale of Maryland, West Virginia, and western New York has been established by C. K. Swartz and other Maryland workers despite the absence of the diagnostic species in the New York fauna and of certain New York bryozoans in the Appalachian fauna.

Correlation Problems in Western Ohio and Indiana

Silurian strata in Clark, Greene, Miami, Preble, and adjacent counties of western Ohio differ in many ways from those in south­ western Ohio, The differences are both lithologic and faunal. Most of the problems concern strata that are younger than the Osgood formation—i.e ., the Laurel, Massie, Euphemia, Springfield, Cedar­ v ille, Huntington (restricted), and New Corydon formations. To explain some of the difficulties involved in understanding the relationship of these strata it is necessary to depart from systematic stratigraphy for a few pages,

A relatively recent study dealing with Silurian rocks is a dissertation on the Niagaran formations by Busch (1939). He stated that the Niagaran rocks of western Ohio, southern Indiana, and northern Indiana are quite different, and that little exact corre­ lation had been made between the three areas. These statements are s till true today, although steps are being taken to remedy the situation. The Indiana Geological Survey is presently engaged in an extensive program to unravel the history and correlation problems of the Silurian in that state. Future investigations are also being planned by geologists in western Ohio. The presence of reefs, the influence of the Cincinnati arch

on facies development, and a scarcity of rock exposures owing to

thick glacial drift, have caused most of the correlation difficulties.

The work of Cumings and Shrock (1928) on the Silurian of north-central

Indiana is probably the most complete and it s till forms part of the

basis for Silurian classification. In recent years information has become available from strategic wells which help to understand the

relations between the various strata. Some of this new information

indicates a larger number of reefs in northern Indiana than was

formerly suspected. Subsurface data in west-central and northern

Ohio also indicate reefs, although fewer in number and generally

smaller than those in Indiana,

Recent investigations in Indiana (Shaver, 1961, p. 29, 30)

show that the name Huntington dolomite has been applied to rocks at

different stratigraphic positions. The name has been used to refer

to bedded Lower Niagaran dolomites in east-central Indiana, although

it was originally intended to apply only to Upper Niagaran reef

dolomites near Huntington in northern Indiana. The New Corydon

limestone constitutes the upper part of the Niagaran in Huntington

County, but the type exposures in Jay County have been reported to

lie stratigraphically below the Mississinewa shale. Other rock units

that may require revision and redefinition, according to Shaver

(1961, p . 7 ) , are the B r a s s fie ld lim eston e and some o f the Lower

Niagaran strata.

In western Ohio, beds correlated by Busch (1939) with the New

Corydon and Huntington of Indiana w ill probably be affected by revisions and redefinitions in Indiana, Shaver (1961, p, 53) writes that Busch relegated the lower U3 feat of a 70-foot section exposed in the abandoned Ridgeville quarry, Randolph County, Indiana, to the

Cedarville dolomite. Above the Cedarville in this quarry is the

Huntington (restricted) of Busch. These beds correspond roughly to the Laurel limestone and Osgood formation in the nearby H. and R.

Stone quarry as identified by Pinsak and Sunderman (Shaver, 1961, p . 53). If the Laurel and Osgood identifications are correct, the strata described as Huntington (restricted) in the Ridgeville quarry occupy a stratigraphic position in the Clinton rather than in the

Lockport.

Another interesting development in Indiana (also in Michigan and Ontario) is the interpretation of certain formations as reef and interreef facies. As far back as 1927, Cumings and Shroek considered the "Huntington lithology" as a phase of reef rock of other formations rather than as a single formation. Lowenstam (19U9, p. 25) considers the Mississinewa shale as a still-water facies of his interreef Thom

Group, Several stratigraphers believe that the Kokomo limestone, which correlates with part of the Salina formation, is partly con­ temporaneous with Niagaran reefs growing in fringing shelf areas of northern Indiana, Shaver (1961, p, 23, 2U) now doubts the existence of the classic disconformity supposed to exist at the base of the

Kokomo. The development o f th e se new id ea s i s helping to u nravel the complex relationships of Silurian strata in Indiana and border areas of Ohio and Michigan, £8

fisarey and Bieberman (19U8) consider the Kississinewa shale as the "key11 to Siluro-Devonian stratigraphy in Indiana, On the basis of insoluble residues and lithology, they correlate the

Mississinewa of northern Indiana with the Waldron formation of southern Indiana, Kesling and fihlers (1962, p, l£) support this correlation. However, Shaver (1961, p, 20) prefers a higher position in the standard section for the Mississinewa, which he considers the host formation for the reefs. He indicates that data from coring, field studies, and faunal evidence support a Lockport position for the Mississinewa rather than the Rochester correlation of fisarey and Bieberman, Cumings and Shrock (1927) and Cumings (1930,

19Ul) correlate the Mississinewa with the Rochester on the basis of graptolites.

The writer believes the Mississinewa is an important unit in correlating between Morrow, Union, Crawford, and Wyandot counties, Ohio, and Tipton and Howard counties, Indiana, Figure 8 shows a cross- section across western Ohio and north-central Indiana utilizing well cuttings and gamma-ray-neutron logs to show probable rock equivalents.

Most of the correlation difficulties between southwestern and western Ohio are thought to be environmental differences caused by the location of the two areas relative to the platform area shown in Figure 7. The shallow platform of western Ohio not only kept most of the fewer fine elastics reaching the area in suspension (it was of course farther from the clastic source than southwestern

Ohio), but the resultant ecology would have been favorable for different forms of marine life than existed in the muddier environment MO 1 NM -M tUl (ItlT t Mb t. ft M. T ItK .I I t. T*tOM CO, MMi «d • c o r w n n - mcomo md i. • f t i r it a n t., j*t co. mo*

p ._J ■*’ '♦» r ~ T ~ i * 1 CROSS - SECT ION QT SILURIAN STRATA FROM [P^iiotcwri lilt* NORTH-CENTRAL INDIANA TO CENTRAL OtflO m inw^QMf 1- | SnT%rowt m »W«yt»lT| L " r3 M *-* WKOMIT ) j VMpvtmi p~~1 \

Cross-section from north-central Indiana tc central Jhio

fig u re 5 vn vo 60 away from the platform. The "clean" (Clinton) carbonates of the platform probably include strata of the Springfield and Euphemia formations whereas the "dirty" carbonates along the margins of the platform consist of the argillaceous and silty Bisher. By early

Lockport time near exhaustion of the clastic source to the southeast along with some basin infilling probably helped to equallize environ­ mental conditions between southwestern and western Ohio. The

Lilley-Cedarville formations show comparable lithologies in part although the fauna of these two formations indicate some differences e x is t e d .

M ississin ew a s h a le . The name M ississin ew a Shale was a p p lied by Cumings and Shrock (1927, p. 72) to beds exposed along the

M ississin ew a R iver in Grant, Wabash, and Miami c o u n tie s, Ind ian a.

No type section was designated. The formation is generally con­ sidered to include the argillaceous rocks below the Liston Creek lim eston e and above the more ca lca reo u s Lower Niagaran s tr a t a .

Cumings and Shrock (1928, p. 583) describe the Mississinewa as a calcareous interreef mud containing 16 and 30 percent silica at

Kokomo and Yorktown, Indiana, respectively.

The term Mississinewa "Shale" is a misnomer. At a fresh exposure the beds appear to be massive blue-gray calcareous shale or argillaceous limestone. The formation weathers drab buff and splits into small slabs resembling typical shale. Under a microscope the rock is a calcareous siltstone. In the Kokomo core, Howard

County, Indiana, the Mississinewa is predominantly gray and greenish-

4 gray silty argillaceous dolomite. Some beds near the base of the 61

formation are tan fine- and medium-grained limestone, and the upper­ most beds are gray dolomitic siltstone. The writer finds the

Mississinewa in well cuttings to be gray argillaceous silty dolomite

or argillaceous dolomitic siltstone that looks very similar to

cuttings from the Eisher formation in southern Ohio. Eastward from

Huntington County and southward from Madison County, Indiana,

Mississinewa strata become increasingly difficult to recognize.

Approximately 75 feet of Mississinewa occurs at the outcrop

near Wabash, Indiana, but nowhere is the entire formation exposed.

Nearly 115 feet of these beds have been identified in the core at

Kokomo, Howard County, Indiana, and 95 feet of Mississinewa is

present in the Wells Estate well in Tipton County. Carbonates of

the reef type occupy the position of the Mississinewa in the Baatz

well, Allen County, Indiana, but in the Wakeland well a few miles to

the northwest nearly 50 feet of slightly silty argillaceous dolomite

is designated probable Mississinewa. The fu ll thickness of the

Mississinewa in Indiana is probably about 115 feet, according to

Shaver (1961, p. 61).

In north-central Indiana the Mississinewa is overlain by the

L iston Creek lim esto n e and u nderlain by unnamed Lower Niagaran

carbonates. Both contacts are reported to be conformable. Patton

(1955, P* 16)- says that the Mississinewa is purer and more dolomitic

in northeastern Indiana, which makes the contacts with overlying and

underlying rocks difficult to determine. The formation is considered

an interreef facies and is therefore absent in the vicinity of large

biohermal masses or reefs. In some instances the formation contains 62 beoherms. In.the Grant County core (Shaver, 1961, p. 16, 57) 97

feet of Mississinewa is overlain by biohermal rocks which occupy

20 feet or more of the Mississinewa stratigraphic position. This

fact was determined by comparison with the thickness of the form­

ation in a nearby quarry.

Shaver (1961, p .'20) correlates the Mississinewa with the

Lockport of New York, although earlier workers and some present-day

geologists correlate with the Clinton. In Figure 8 the Mississinewa

is shown to be stratigraphically equivalent to the Bisher formation.

The lithology of the two formations is partly similar also. The

substantial local thickness of the Mississinewa and its copious silt

content in areas far from the clastic source proposed for the Bisher

suggest the possibility that the Mississinewa may be partly derived

from the Bisher by erosion. Another theory is that the thin nearly

silt-free Bisher and its equivalents along the western border of

Ohio are the result of extremely shallow-water wave turbulence which

kept the silt and argillaceous material from settling permanently

over the higher part of the Cincinnati-Findlay platform, borne of the

fine clastic material .was carried by currents around the southern end

of the platform and finally deposited in the protected interreef zone

of north-central Indiana as the Mississinewa beds.

Stratigraphic Relations within the Clinton Group

The Oldham and upper Brassfield beds in the subsurface of

southern Ohio and northeastern Kentucky have partly similar lith ol-

ogies (as in the type area) and cannot be separated except under ideal conditions. Gamma-ray-neutron logs are helpful, along with well cuttings, if the intervening shale is sufficiently developed to be recognizable. One might quarrel with Foerste1s original sub­ division of the section near Brassfield, Kentucky, or with the writer's reclassification of subsurface beds formerly considered

Brassfield in conformity with the original subdivision, but it is believed that recognition of the continuity of Oldham strata in the deeper parts of the Appalachian Basin east of the outcrop areas contributes to an understanding of the Silurian (Figure 6).

The entire Clinton group 'thins and nearly disappears to the northwest in Crawford and Vfyandot counties, Ohio. Approximately 30 feet of carbonate strata is all that remains. Significant erosion at the end of Clinton time, or a succession of lesser breaks in sedimentation (diastams) must be invoked to explain this thinning.

It is believed that much of northwestern and part of central Ohio was a positive area in Niagaran time owing to the presence of the

Findlay platform. Shallow water depth would prevent the accumulation of much permanent sediment. Figure 7 suggests shoal-water conditions on a shelf area during late Clinton and early Lockport time.

The upper $0 feet of the driller's Clinton shale (well No. 3 on Figure 10) is roughly equivalent to the argillaceous lithofacies of the Bisher formation in east-central Ohio. The lower 100 f e e t o f this Clinton shale is composed of the typical greenish-gray and gray shales of the Estill-Rose H ill formation, which represent mildly reducing conditions of deeper water and quicker burial of sediment.

Near the close of Clinton time there was a recession of the shallow epicontinental seas (or less probably renewed uplift along the

Findlay arch), which caused a shoaling of water. Under these

conditions the iron-rich sediment was aerated and oxidized con­

tributing a brownish color to the argillaceous dolomites and

dolomitic shales of the Bisher.

The origin of the Mississinewa Shale of Indiana has puzzled

geologists. It is possible that the upper Mississinewa represents a

concentration of s ilt eroded from earlier sediments (Bisher or

Brassfield), but the writer believes most of the formation is

equivalent to the Bisher in southwestern Ohio. The concentration of

silty Bisher in southern Ohio and its absence from the agitated

water on the platform or shelf in northwestern Ohio suggest that

currents moved the silt westward along the southern border of the

platform through a slightly deeper portion of the shallow seas that

existed along the Ohio-Indiana state line (Figure 7). Freeman (1951,

p. 10-12) gives evidence for a gentle swell at the position of the

Lexington dome near the south end of the Cincinnati arch. Perhaps

this swell or platform blocked the passage of silt and sand into

southern Indiana or perhaps these sediments were deposited and later

eroded. Shaver (l?6l, p. 1$, 6l) describes nearly ten feet of

Mississinewa shale beneath Devonian dolomite in the Hancock core

indicating the Mississinewa may have been once present in southern

Indiana but was later eroded. The thickest beds of the silty

Mississinewa are preserved in the interreef areas of north-central

Indiana. Geologists (Lowenstam, 1950, p. U81-82) acknowledge some

reef-building began in Early Niagaran (Clinton) time in parts of Michigan, Indiana and Ontario. Thus it is perfectly possible from this viewpoint that the Mississinewa represents an interreef facies during part of Clinton-Lockport sedimentation and also represents part of the contiguous Bisher-Mississinewa seas. Bisher strata in th e Lake w e ll in Muskingum County occupy a p o s itio n j u s t beneath dolomite that appears to be a biostromal accumulation. This condition is even more apparent along the zero line of the Bisher formation

(Figure 7). As reported elsewhere in this paper the upper part of the Bisher (equivalent to part of the Lilley) may be of early Lock­ p ort a ge.

Lockport Group

James Hall in 1839 called the limestone excavated in building the Erie Canal at Lockport, New York, the Lockport limestone. It consists of a basal crinoidal limestone, calcitic dolomite (sometimes cherty), and cream-colored sugary-textured dolomite. Fisher (1959)

states that patch reefs occur in the basal limestone (Gasport unit).

In the type area the lockport overlies the Rochester shale

and underlies red shale of the Balina formation. In geological re­ ports after 1839 some authors included the Guelph dolomite in the

Lockport and others excluded it. The United dtates Geological Survey

uses the name Lockport in a formational sense for the dolomite (which

includes beds witji Guelph fauna) that underlies the Saline. and over­

lies the Clinton formation in New York and Michigan. Fisher (1959)

uses Lockport as a group name. 66

L illey Formation

The name Lilley was given by Foerste (1917, p. 190) to beds which Orton had previously called the "Blue Cliff" stone. The name is taken from Lilley H ill at Hillsboro, Highland County, Ohio. Six years later Foerste (1923, P« U2) raised the Lilley to formation rank, and in 1935 he redefined the contact between the Lilley and

Bisher formations. At the type locality the Lilley is a gray to bluish-gray finely crystalline argillaceous dolomite with some shale partings and a 3-foot shale layer at the top.

The most detailed study of the Lilley is that of Bowman

(1956), who finds that the greatest lithologic differences in the

Niagaran of southern Ohio occur in this formation. He divides the

Lilley into three principal lithofacies (1956, p. 17), one or a ll of which may be present at a given outcrop. The first is a crinoidal carbonate lithofacies, which is the most characteristic Lilley studied by Bowman in Highland County, It is generally light gray, medium- to coarse-grained porous dolomite that contains numerous fragments of crinoid stems. The second is an argillaceous carbonate lithofacies. This is the one exposed at the type locality, though it is considered a minor lithofacies in Highland County. It becomes more prominent to the south in Adams County and consists of gray to bluish-gray finely crystalline dolomite or calcareous dolomite with a few crinoid stems. The third or dolomitic shale lithofacies is dark gray to blue-gray dolomitic shale that is only locally present in Highland County. ino 'sk* M

| | | | | UNCONFORMITY

FORMATIONS ARC NOT DRAWN TO ANT VtATICAL OCALC

JO 00 40 00 M IL IO

A.L. MORVATN - 1004

REGIONAL stratigraphic r e l a t i o n s f o r t h e l o c k p o r t g r o u p FIGURE 9 68

Bowman mentions two minor lithofacias: a light tan to gray- crystalline, fine-grained dolomite which he says is probably related to the crinoidal carbonate lithofacies, and a siliceous carbonate lithofacies along the north bluffs of the uhio River.

One of the purposes of this investigation is to determine whether the Lilley formation can be traced into the subsurface.

Efforts to trace it from the Highland County outcrop were successful within the lim its shown on Plates II and III. All three of the major lithofacies are present in cuttings from the Wenzel well, Ross

County, Ohio. The crinoidal carbonate and argillaceous carbonate are found in the Anderson well, Pike County, in the Grover well,

Jackson County, and in the Dever well, Scioto County. In the sub­ surface of Jackson, Scioto, and other Ohio counties to the east, basal beds of the Lilley contain increasing amounts of silt, which make the formation difficult to differentiate from the underlying

Bisher. The writer regards the several lithofacies of the Lilley as transitional beds between the silty argillaceous carbonates of the Eisher and the purer dolomites of the Peebles. The environmental conditions that produced the Eisher were operative during deposition of the Lilley beds. It is probable that parts of both formations were deposited contemporaneously in neighboring environments as

Bowman su g g e sts.

The most useful lithofacies of the Lilley in subsurface correlation are argillaceous carbonate and gray crystalline fine­ grained dolomite which the writer finds to be slightly argillaceous in well cuttings. The two are considered gradational. It is 6 9 fortunate that where two or more lithofacies comprise the Lilley, the upper beds nearly always consist of the gray, more or less argillaceous carbonate. Thus the upper contact can be picked with a fair amount of precision wherever the overlying Peebles consists of relatively pure carbonate beds.

The L illey is traceable from the Highland County outcrops northward to Pickaway, Fairfield, and Perry counties. The formation may also be traced eastward to the western boundaries of Athens,

Morgan, and Muskingum counties, Ohio. Beyond these lim its to the north and east the Lilley cannot be differentiated with certainty from other Niagaran formations. The writer traced the Lilley as far south as Lewis and E lliott counties, Kentucky, by means of well cuttings. The formation has been reported by McFarlan (1938, p. 336) in the subsurface of E still County, Kentucky, where it is an oil reservoir in the Irvine field.

The Lilley ranges in thickness from nearly 80 feet in northern Highland County to about 30 feet in southern Adams County,

Ohio. In Clinton County to the north, Bowman (1956, p. 6 $) found lithology resembling the Lilley in rock that had been identified as

Cedarville. He believes the Cedarville is the northward extension of the Lilley formation. Most of the wells in southern Ohio show the Lilley to range between 30 and 80 feet in thickness. The absence of a consistent pattern of thickening and thinning supports Bowman's contention that the Lilley and Bisner are partly time-equivalent.

The Lilley conformably underlies the Peebles and overlies the

Bisher. Occasionally there is obvious interbedding of Lilley and 70

Bisher strata. In the subsurface eastward from the Highland and

Adams c o u n ties ou tcro p , b a s a l L ille y s t r a ta show in c re a se d s i l t residues, which tend to obscure the lower contact with the Bisher,

particularly where the latter contains some crinoid fragments.

The Lilley can be traced eastward into the deeper part of

the Appalachian basin, where it loses its identity in the basal

Lockport of eastern Ohio, The Lockport in turn is traced laterally

into the KcKenzie limestone of -West Virginia, The argillaceous beds in the Lilley-basal Lockport of eastern Ohio are apparently

continuous with the shaly basal limestones of the KcKenzie. Bowman

(1956, p, 72) believes the Lilley is correlative with at least the

upper part of the Lockport in the region of the Ontario Peninsula,

He also correlates the Lilley with the Cedarville formation in

Clinton, Greene, and Clark counties, Ohio, on the basis of lithology,

stratigraphic position, and general faunal characteristics, although

he admits that specific faunal comparison shows few sim ilarities.

The writer finds it to be equivalent to the Lockport of Ontario on

the basis of stratigraphic position,

Cedarville formation. Orton (1871, p. 277-78) proposed the

name Cedarville or Guelph limestone for a distinct lithologic unit

and used the local designation of Pentamerus limestone because of the

prolific occurrence of this brachiopod within the formation. In

1873 (p. U71) he designated the type locality as numerous quarries in

Cedarville, Greene County, Ohio.

The fresh Cedarville rock is a very light gray to light

grayish-brown, holocrystalline porous dolomite with small irregular 71 cavities largely resulting from the solution of cystoids and crinoids.

Weathering causes much of the Cedarville to break down into thin irregular beds.

A complete section of the Cedarville is not exposed anywhere.

Approximately !?3 feet of strata is exposed in the type locality and

Eusch (1939, P« 106) estimates a maximum thickness of 9$ f e e t fo r

this formation. The writer examined Cedarville rock at Clifton,

Greene County, Ohio, and compared i t with samples from the Peebles and Lilley formations in southwestern Ohio. No certain identifica­

tion on the basis of lithology could be made on this single sample.

The Cedarville at Clifton was intermediate in texture between the more coarsely crystalline crinoidal Lilley and the somewhat finer

Peebles rock. The tan to light grayish-brown color fits either

correlation.

The Cedarville conformably overlies the Springfield dolomite which it resembles in small crushed samples. The upper contact of

the formation is not exposed in Ohio, In the Fairview quarry in

Indiana, rocks of Huntington lithology conformably overlie strata

originally identified as Cedarville. This identification is now doubted by personnel at the Indiana Geological Survey.

According to Busch (1939, p. 129, 131) the Cedarville

correlates with the Bacine of Wisconsin and with the upper Lockport- pre-Guelph of Ontario and New York. Bowman correlates the Cedarville with the Lilley formation in southwestern Ohio although conclusive

paleontological evidence is lacking. Peebles Formation

Niagaran strata at Lilley Hill near Hillsboro, Ohio, were called Guelph, Cedarville, or Pentamerus Limestone by Orton (1871, p. 277, 278, 3 0 1 ), These beds were later reclassified as the

Peebles formation, a name derived from the town of Peebles in northeastern Adams County, Ohio. Foerste (1929, p. 168, 169) applied this name in itially to beds between the overlying Greenfield east of the town of Peebles and the underlying Lilley to the west of town. He misidentified the argillaceous id lle y strata underlying the Peebles as the Bisher formation, but Bowman (1956, p. 75) later corrected the error.

The Peebles is a light gray fine- to medium-grained relatively pure fossiliferous dolomite along the outcrop in Adams and Highland counties, Ohio. Exposures can also be found in western Pike, Ross, and possibly Clinton counties. The rock is pockmarked with small solution cavities or micro-vugs, some of which were probably fossil shells which have weathered out. Locally these cavities contain asphaltic material, as do some overlying zones in the basal Green­ field and occasional zones in the underlying Lilley. The Peebles is typically a pure dolomite, which in places yields insoluble residues of only 0 .1 to 1 .0 percent. According to Butterman (1961, p. U5), it contains less residue than the Lilley, but about the same amount as the overlying Greenfield.

The Peebles observed in well cuttings is light gray or light gray-brown fine- and medium-grained partly crystalline d o lo m ite. A w ell-developed zone of p o ro s ity , known a s the Newburg 73 zone in drillers* terminology, is usually present in the upper part of the formation. The Peebles can be recognized in the subsurface of Pike County not far from the outcrop sections described by

Bowman. From there the formation can be traced eastward until it loses identity in the upper Lockport near the Ohio-West Virginia state line. Northward from Pike County the Peebles may be traced with increasing difficulty as far north as the Riggs well, Morrow

County, Ohio. North of this well the relationship of typical

Peebles to overlying reef carbonates or to the brown dolomites of the upper Lockport and Greenfield becomes more complex. Detailed stratigraphy north of Morrow County is beyond the scope of this paper. It is interesting to note that Ulteig (1963) does not sub­ divide the Lockport in northern Ohio. He states (1963a, p . 6U) that the various lithologies of the Lockport as subdivided and named at the outcrop are not recognizable in the subsurface.

Southward from Pike County, Ohio, well cuttings show the

Peebles to occur in the Shepherd well, Lewis County, Kentucky, and it has been reported in the subsurface of JSstill County, Kentucky, by McFarlan (19U3, p . 3 lU ).

A greenish-gray clay deposit, which occupies depressions on the ancient Peebles surface at many outcrops, can occasionally be detected in well cuttings. In the Wenzel well, Ross County, Ohio, the presence of this clay in cuttings, and on the gamma-ray-neutron log pinpoints the contact of the Peebles with the overlying Green­ field formation. The lithology, faunal content, and thickness of the Peebles dolomite in the western half of Ohio have been interpreted as indicating a reef complex by some geologists (Travis, 1962j Ailing and Briggs, 1961). The lithology and thickness of carbonate rock occurring at the approximate stratigraphic position of the Peebles in some w e lls in Union, Morrow, and Crawford co u n ties su g g e st r e e f origin. Ulteig (1963a, p. 65) interprets this thickening as part of a northwest-southeast connecting basin between the Michigan and

Appalachian basins.

The absence of a uniform pattern of regional thickening or thinning is indicated by subsurface information. In a general south- to-north direction, well data show 85 feet in eastern Pike County,

125 f e e t in Ross County, and 50 f e e t in Pickaway County, JSastward from the outcrop, over 100 feet of Peebles strata are present in the Attinger well in western Pike County. The formation thins to

85 feet in central and eastern Pike County, and maintains this thick­ ness further east in Jackson County. Beyond this point the formation is difficult to trace (Plate II).

The Peebles is conformably underlain by the Lilley formation.

The boundary (where not gradational) can be discerned by a distinct change to the darker gray argillaceous Lilley. Where the upper Lilley consists of relatively pure dolomite, the Lilley-Peebles contact can only be approximated. The argillaceous Lilley shows slight gamma- ray-neutron characteristics which are helpful in picking the contact.

Westward from eastern Highland and Adams counties toward the Cincinnati arch, tha Peebles is progressively overlain by the Green­ field formation and the Ohio shale. This latter relationship can be observed in only a few places, since both the Peebles and the

Ohio shale are absent over most of the arch due to erosion. Green­ field strata overlie the Peebles formation in most of the area of

investigation, A local relief of at least 3 feet on the Peebles

surface and the presence of the clay along the undulating contact

indicate an erosional unconformity in Highland County (Bowman, 1956,

p . 1U3).

Foerste (1935, p. 192) correlated the Peebles formation of

southern Ohio with the Guelph formation of southern Ontario, primarily

on the basis of 3 brachiopods, 1 pelecypod, 2 colonial corals, and

1 gastropod. A total of 13 species found in the Peebles have been

reported in the Guelph, Bowman (1956, p. 810, i-n agreement with

Foerste, declares the Guelph and Peebles are lithologically and

faunally very similar,

McKenzie Formation

This name was derived from Pinto-McKenzie station on the

Baltimore and Ohio Railroad, 9 miles south of Cumberland, Maryland,

and was applied to the interbedded shale and limestone exposed there.

The rocks were first described by Stose (1912), although Ulrich

introduced the name in 1911 in his Revision of the Paleozoic Systems.

The McKenzie formation consists of limestone, dolomite,

shale, siltstone, and sandstone, Travis (1962, p. viii) says that

shale, siltstona and thin limestone predominate in northeastern West Virginia and that limestone and sandstone are more abundant to the south and southeast. On the outcrop in western Maryland and eastern West Virginia, four lithological subdivisions of the

McKenzie are recognizable, although not everywhere present:

U, Arenaceous shal 9 and interbedded limestone including some redbeds in easternm ost exposures,

3. Upper calcareous shale and limestone,

2. Sandstone member,

1, Lower calcareous shale and argillaceous limestone,

F, M, Swartz believes that the intertonguing redbeds near the top are the westward extension of the Bloomsburg redbeds. The middle sandstone member is also red in Maryland and resembles some of the Bloomsburg higher in the section. Locally the red sandstone is called the Rabble Run member, Travis (1962, p, 27-29) describes a massive dense subquartzitic sandstone, mostly white but weathering rust-colored, with a basal Leparditia zone, one mile east of Hunters­ ville, Pocahontas County, West Virginia. This may be a-westward equivalent of the Rabble Run member. The identification of this sandstone within the McKenzie of West Virginia was originally made by Wells and Dally in 1961. Unaware of its existence, previous workers had confused it with the Williamsport or Keefer sandstone at both the outcrop and in the subsurface.

The Dean and Damron wells in Greenbrier County, ’West Virginia show a s u b s ta n tia l sandstone member w ith in the McKenzie. Other w ells in Preston, Randolph, and Fayette counties, West Virginia show thinner sandstone and siltstone members. Wells along a north-south 77

trending belt on both sides of the Ohio-West Virginia state line in

Belmont, Monroe, Washington, and Meigs counties, Ohio, and in Wood,

Jackson, Mason, Putnam, and Kanawha counties, West Virginia, show the

McKenzie limestone intertonguing with the Lockport dolomite. The

latter is the undifferentiated subsurface equivalent of. the Peebles-

Lilley formations.

The McKenzie i s 2k0-23>0 f e e t th ick a t i t s type l o c a l i t y .

F, M. Swartz (193U) states that 3$5 feet of strata are present at

Mt. Union, Huntington County, south-central Pennsylvania. Reger

measured 2i|0 feet of McKenzie at Ketterman school in Grant County

and approximately 15>0 feet near Huntersville, Pocahontas County,

West Virginia. A thickness of 3U0 feet was found in wells in

Harrison and Preston counties. Other West Virginia deep wells show

thicknesses that generally range between 100 and 2^0 feet, except the

Damron w ell in Greenbrier County which has the maximum thickness, over

500 feet. The above data indicate the thickest McKenzie beds extend

-from Mt. Union, Pennsylvania southward through Preston and Harrison

counties, northern West Virginia to Greenbrier County, southeastern

West Virginia. The formation thins westward into Ohio and also thins

south and east of the West Virginia-Virginia state boundary. Absence

of these beds from west-central Virginia indicates a McKenzie hiatus

in this region.

In the eastern outcrop of West Virginia, the McKenzie is over-

lain by the Williamsport sandstone, which Reger (1?2I+, p. 396-98)

considered to be a member of the Bloomsburg red shale of Pennsylvania.

The Williamsport thins in the western part of the state, and is locally absent where the Wills Creek formation overlies the McKenzie*

In the latter instance the upper contact is between carbonate beds and is more difficult to ascertain. The McKenzie contains more limestone members than the underlying Rochester which is predominantly shale in northeastern West Virginia, although it contains limestone in some localities. In many areas the contact between the two is gradational. At the surface, fossils are utilized to place the contact between limestone coquinas containing W hitfieldella mary- landioa above, and limestone containing an abundance of Schell- wienella elegans below (Woodward, 19^1, p. 120), In the subsurface this contact must be chosen primarily on the basis of increased argillaceous material as shown by sample cuttings and geophysical logs. In southern West Virginia, where the Keefer snadstone under­ lies the McKenzie, the lower contact is less of a problem except where the lower McKenzie consists of arenaceous carbonates.

In 1935 F. M, Swartz advocated a Lockport correlation after a thorough study of the McKenzie in which he attempted to explain the lack of typical Lockport fauna as a result of environmental conditions. Travis (1962) describes the relationship between the

McKenzie and Lockport formations, and says there is no significant break between Rochester and McKenzie deposition. The McKenzie formation can be traced from the outcrop in West Virginia westward into the subsurface Lockport of western West Virginia and eastern

Ohio, which in turn can be traced to fossiliferous Pebbles-Lilley outcrops in southwestern Ohio that correlate with the Lockport of

Ontario and western New York. 79

Liston Creek limestone. In 1927 Cumings and Shrock named strata exposed along Liston Creek in southwestern Wabash County,

Indiana, the L iston Creek lim esto n e . The same authors then red efin ed and renamed these beds the Liston Creek formation (1928, p. 71). The revised definition includes a ll strata between the top of the

Mississinewa shale and the base of the Huntington dolomite, including a local Red Bridge member. The Indiana Geological Survey has now returned to the original definition-by excluding the Red Bridge, a name they do not use. Typically the Liston Creek consists of gray to tan fine- to medium-grained cherty limestone with fossil fragments, occurring in thin beds. This lithology is found at exposures in

Madison, Grant, Wabash, and Huntington counties, Indiana. The lower rocks exposed in the Yeoman Stone Company quarry a t Kokomo, Howard

County, Indiana, are said to be thicker bedded and more argillaceous than typical Liston Creek strata.

The writer examined the Liston Creek interval in the Kokomo core and located similar strata in the Wells Estate well in Tipton

County, Indiana. An attempt to trace this formation eastward from

Tipton County by means of well cuttings and gamma-ray-neutron characteristics proved unsuccessful, as the formation has been eroded from the Cincinnati arch. The color and grain size of the

Tipton County well cuttings resemble those of the Peebles in Ohio, but the Liston Creek differs from the Peebles by being predominantly limestone and containing distinctive porcellaneous chert. The writer believes that the Liston Creek is stratigraphically equivalent to 80 the middle unit of the Lockport formation in the subsurface of northern Ohio and Ontario.

The upper contact of the Liston Creek is not exposed at the outcrop, and for this reason and because nontypical strata have been observed in well cuttings, most geologists consider the exact stratigraphic position and thickness of the formation to be uncertain.

The contact with the underlying Mississinewa shale is said to be conformable. The age of the Liston Creek has been variously stated as Lockport and pre-Lockport. It is currently placed well up in the Lockport-Guelph Group by Shaver (1961, p. 21).

Huntington limestone. The Huntington limestone was named by

Kindle (190U, p. U08) for rock exposed in quarries near Huntington,

Indiana. Cumings and Shrock (1928, p. 9^) renamed it the Huntington dolomite, and relocated the type section to nearby outcrops along the Little Wabash River. They designated a new type locality because several distinct formations, complicated by a great coral reef plexus, had become exposed at the original type locality. The

Huntington as redefined is a yellowish to grayish saccharoidal dolomite exposed along the river channel from NElA> SWl/U, NEl/U,

Section 13, T. 28 N., R. 9 E. eastward nearly to the west line of

Section 8, T. 28 N., R. 10 E., where a cherty foxmation comes in above the Huntington.

Shaver prefers Cumings and Shrock1s (192?) original idea that the Huntington should not be considered a formation but. rather a reef phase of other formations. The Liston Creek has been identified throughout the area surrounding Huntington, Indiana, where some of it is in intimate association with the reef complex but nowhere has the Huntington been found to overlie the Liston

Creek (Shaver, 1961, p, 22), The name has been discontinued by the

Indiana Geological Survey, Rocks exposed near the Huntington,

Indiana, type locality are considered to be of Lockport or Upper

Niagaran age, but the 11 Huntington'1 of Randolph and Jay counties, eastern Indiana is now thought to consist of strata that overlie the Brassfield and underlie the Mississinewa Shale, a position that

indicates an Early Niagaran age. Shaver (1961, p. 29), in fact,

suggests that strata containing Huntington fauna very nearly span

the Niagaran, and he attempts to reconcile the conflicting evidence.

This idea is supported by cuttings from the ‘./akeland well, Allen

County, Indiana, which show 250 feet of dolomite in the upper part

of the Niagaran and UO feet or more in the lower part. These cuttings

strongly resemble the Huntington rock.

In west-central Ohio and adjacent parts of Indiana, Busch

(1939, p. 110-112) restricted the Huntington by applying it to that •

part of the formation containing Guelph fauna. The Indiana Geo­

logical Survey considers the Huntington (restricted) at the Ridgeville,

Indiana, quarry equivalent to the Laurel and possibly to part of the

Osgood formation. The exclusive Guelph affinities of Pentamerus

oblongus, which is used by various geologists to correlate Huntington

strata, has been disproved, Bolton (1957, p. ijl) states this species

is also characteristic of middle Clinton rocks along the Niagaran

Escarpment in Ontario. 82

In view of the preceding facts, the Huntington is omitted as a formation name from the correlation chart (Figure 3). It is considered as a reef phase of the Liston Creek, Mississinewa, and other formations in Indiana. No reliable correlation can be made concerning the Huntington (restricted) outcrops of Ohio on available evidence. These exposed rocks are probably equivalent to either the

Laurel or Liston Creek of Indiana. It is recommended that these critical outcrops be re-examined.

New Corydon lim e sto n e . The Mew Corydon lim eston e was named by Cumings and Shrock (1928, p. 113) for strata exposed in quarries near New Corydon, Jay County, Indiana. It consists of brown cherty irregularly bedded limestone with intercalated carbonaceous partings, ranging from a few feet to 20 feet in thickness along the outcrop.

Two years later, Cumings (1930a, p. 183-190) said the New Corydon was a middle member of the Huntington dolomite, and identified 100 feet of this limestone within a L^O-foot total section of Huntington dolomite in a deep well at Fort Wayne, Indiana, Shaver (1961, p. 23) b e lie v e s the New Corydon exposures along the L it t le Wabash R iver

east of Huntington represent an off-reef near-normal lithology of

the Liston Creek, whereas strata exposed at the type locality in

Adams County are thought to be below the stratigraphic position of

the Mississinewa shale.

Rock named New Corydon in western Ohio does not correspond to

the 1930 redefinition of Cumings, since Busch (1939) apparently con­

sidered New Corydon strata to overlie the Huntington formation as

stated in the original definition. Cumings and Shrock (1928b, p. ll£) 83

also stated that they knew of no formation like the New Corydon in

western Indiana or Ohio.

Patton (19l|.9, p. 12) suggests that the New Corydon is a

more dolomitic eastward facies of the cherty upper part of the Liston

Creek. Approximately 75 feet of cuttings from the lakeland well,

Allen County, Indiana, fit the Mew Corydon description. In northern

Ohio and southern Ontario similar beds have been called brown

Niagaran or brown Lockport. The Lockport fauna of the New Corydon

is compatible with this correlation, but the ambiguous usage of the

name by geologists has caused confusion and for this reason the term

is omitted from the correlation chart, terhaps redefinition and

careful correlation w ill make the New Corydon a useful and valid

formation name at some future time.

Stratigraphic Relations within the Lockport Croup

In order to interpret the Lockport of central Ohio, it is

necessary to consider similar strata in areas to the north where the

relationship has been worked out. Imperial Oil Company graciously

permitted Jack Pounder to supply the writer with necessary informa­

tion from southwestern Ontario.

The Guelph-Lockport strata in the subsurface of Ontario

are subdivided into three lithologic units, which are correlative

throughout the area and can be traced into northern Ohio. The upper

unit is believed equivalent to the Guelph and the middle and lower

units to the Lockport. According to Pounder (1963), the lower unit when present ranges from a few feet to 387 feet in thickness and grades from a brown or gray crinoidal limestone or dolomite to a white or gray reefal (bioherm or biostrome) dolomite. If the lower unit is biohermal, the reef may extend into the middle unit and in some places into the upper unit. The lower unit is roughly correlated with the lower Albemarle in the Bruce Peninsula and the Gasport formation in the Niagaran area. Since this unit may grow into pinnacle reef proportions and may penetrate the upper unit it is understandable that no precise stratigraphic position should be assigned to it.

The middle unit represents the bulk of Guelph-Lockport sediment in Ontario and ranges from 30 to 2£o feet in thickness.

It consists generally of brownish-gray argillaceous finely crystal­ line dolomite, although it may also be dark gray to greenish-gray mottled argillaceous dolomite. The unit is thought to correlate with the Goat Island and Eramosa formation of the Niagara Peninsula.

The upper unit consists of gray to buff crystalline frag­ mental dolomite, ranging from 10 to 100 feet in thickness. This unit is primarily an erosional product derived from earlier reefs and sediments. According to Canadian geologists, numerous unconformities can be detected within the unit, as well as one at the top.

The middle and lower units are present in the Haff well,

Sandusky County, northern Ohio. All three units were noted in the

Mertler well in Richland County (Figure 10). The Eckert well in

Wyandot County, the Blicke well in Crawford County, and various other

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Crosa-section from southwestern Ontario to eastern Ohio Figure 10 wells in northern Ohio indicate the presence of reefal dolomites of the lower unit and a possible pinnacle reef is suggested by the thickness and lithology of the lower unit in the WIndbigler well in Morrow County. An examination of cuttings showed that the lower and middle units and possibly an equivalent of the upper unit of the

Canadian Lockport-Guelph are present in the Wakeland and Baatz w ells,

Allen County, northeastern Indiana. The middle unit constitutes the bulk of the Lockport formation in Ohio, as it does in Ontario. The writer believes that the Peebles and Lilley formations of southern

Ohio, most of the subsurface Lockport in eastern Ohio, and the

Liston Creek formation of Indiana are equivalent to this middle unit. The Huntington reef rock of Indiana is probably equivalent to either the upper or lower unit, or to both, depending on the l o c a l i t y .

S a lin a Group

Dana in 1863 proposed the name Salina period to include epochs of "Saliferous" and Guelph limestone deposition. Years later the Guelph was transferred to the Niagaran group, in which it is now included. Goldring (1931, p. 337) included a ll workable gypsum deposits along with the salt in the Salina formation of central and western New York. Although the formation is named for Salina, New

York, where it supplies salt wells, the type locality is given as

Syracuse, New York.

Landes (19U£) subdivided the Salina formation of the Michigan

Basin into units A through G in ascending order. He traced unit A into the Greenfield dolomite of northern Ohio,, and correlated B through G with the Tymochtee formation. The Salina group name became firmly established when Ehlers, Stumm, and Kesling (1951, p. 10) reclassified the Greenfield and Tymochtee dolomites as part of the Salina Group.

Greenfield Formation

Orton (1871, p. 289, 291) described strata exposed at the

Rucker quarry near Greenfield, Ohio, and referred to them as the

Helderberg limestone or Greenfield stone. The formation was later called the Greenfield dolomite by Lane and others (1907, p. 55U), who assigned it to the lowest part of the Bass Islands Series.

More recently, Ehlers, Stumm and Kesling (1951, p. 10) placed the

Greenfield and Tymochtee together in the Salina Group.

Outcrops of the Greenfield are described as gray, brownish- gray, or medium brown fine- to medium-grained distinctly bedded dolomite, with occasional massive zones near the base. The texture may be granular, crystalline, or partly oolitic. Carbonaceous laminae are sometimes present. The basal Greenfield beds are locally porous or vugular, with or without asphaltic material' in the openings. Sometimes this porous zone is shared with the upper part of the Peebles, to form the productive Newburg zone of driller terminology. However, this term has also been used to refer to porous zones at lower stratigraphic positions.

In th e subsurface the G reen field i s m ainly medium brown or gray-brown fine- and medium-grained partly crystalline dolomite, with SALINA GROUP ONAL GRAPHI ONS FR NA GOUP GRO A IN L A S E H T FOR S N IO T A L E R IC H P A R IG T A R T S L A N IO G E R / / / ✓ / / / /

GURE II E R U IG F - ^ / 7 ? I? 0 n m 0 2 UILCS UILCS FOI 9 5 0 4 g S .. OVT 4 0 0 1 • HORVATH A.L. a slightly argillaceous residue. A sparkling effect from scattered crystals is sometimes referred to as sucrosic (Miller, 1955) , although the writer prefers the term micro-sucrosic, since sucrosic is a more apt description for some of the more coarsely crystalline

Lockport. The formation contains anhydrite beds or lenses in most of southern Ohio, but no evaporites are present in wells near outcrop areas in southwestern Ohio. Other textural characteristics such as oolites, carbonaceous laminae, zones of vugular porosity, and asphaltic material were found to be locally present in well cuttings.

Silty residues were obtained from the basal Greenfield (particularly from oolitic dolomite) in some wells in Athens, Meigs, Noble, and

Jackson counties. These residues were helpful in locating the lower boundary of the formation, but similar silty zones were later found at higher positions in other wells, mitigating their stratigraphic usefulness. The writer did not attempt a systematic analysis of

Greenfield residues, although this is something that should be investigated. Butterman (1961, p. 76) obtained fine sand in residues from the basal Greenfield at Ralph Rodgers quarry, Pike County, Ohio.

These silty carbonate beds prove interesting when compared with possibly equivalent strata of the Kokomo formation in Indiana or the

Williamsport member of the ’Jills Creek formation in West Virginia.

Although only 60 feet of Greenfield beds are exposed at

Greenfield, northeastern Highland County, Ohio, H iller (1955, p. 3h)

estimates that an additional 15 to UO feet of the fozmation is

covered. Eastward from Highland County, U3 feet of strata are present in the Anderson well, Pike County; UO feet in the Grover wellf Jackson County; approximately 100 feet in the Buckeye No. 2 well, Jackson County; and about 75 feet in the Arrington well just across the Ohio border in West Virginia. The Greenfield may also be traced from Ohio eastward into the Sand H ill well, Wood County,

West Virginia where strata between 6930 and 6980 were assigned to this formation. This thickness differs from the 6880 to 6980 interval assigned to the Greenfield by Shearrow (1957* p. 30).

A gradational Greenfield-Lockport lithology occurs from 6980 to the McKenzie contact at 7070 feet in this well. Well cuttings in­ dicate that the Greenfield thickens northward, from less than feet in Scioto and Pike counties to 230 feet or more in Fairfield,

Licking, and Delaware counties. These figures are apt to be mislead­ ing with regard to the regional picture, however. Ulteig (1963, fig.

8) shows that the pattern of Greenfield thickening in northern Ohio corresponds to areas of Lockport thinning and conversely where the

Lockport thickens the Greenfield thins. The Greenfield was found to thicken southward from Scioto County into Kentucky. Over 100 feet of

Greenfield was observed in well cuttings from the Williams No. 8 well, Johnson County, Kentucky. It is interesting to note that surface records and well data indicate over 50 feet of the formation in the Bellefontaine outlier, suggesting that the Greenfield covered at least this part of the arch at one time.

At the outcrop in Highland County, Ohio, the Greenfield disconformably overlies the Peebles formation (Bowman, 1956, p. 76), but in the subsurface to the east the contact is gradational. The

Greenfield-Peebles contact can be readily recognized in many wells by the change from brown usually anhydritic and micro-sucrosic dolomite above to relatively pure and generally light-colored fine- to medium-grained dolomite below. However, the Lockport often has a brownish color which makes the contact difficult to choose especially in areas where only traces of anhydrite which may represent 11 caving" are present. Particularly in eastern Ohio the Greenfield beds are difficult to separate from similar underlying Lockport strata. In­ soluble residues are sometimes used to detect the.slightly more argillaceous Greenfield beds. This technique is not entirely acceptable since it is based on a relationship that exists in western

Ohio but not along the Ohio-West Virginia border where the partly argillaceous McKenzie limestone is present. South of Highland

County in the vicinity of the Ohio River the Greenfield beds are missing as a result of the Siluro-Devonian unconformity, and the Ohio shale rests directly on the Peebles (Butterman, 1961, p. 72). The upper contact with the Tymochtee is conformable at the Plum Run quarry, Adams County, Ohio, such as in the Attinger well in Pike

County, where erosion removed Tymochtee strata preceding deposition of the Ohio shale.

The Greenfield can be traced eastward into the basal Wills

Greek formation, and into underlying beds that form the upper part of the Lockport in published descriptions of the Sand Hills well, Wood

County, 'West Virginia (Haught, 1956). Ailing and Briggs (1961, p. 529-

38) state that the sparingly fossiliferous Greenfield beds contain species of the ostracod Leperditia, and the brachiopods Hindella rostralis (Whitfield ), Schuehertella interstriata (Hall), W hitfieldella sub sulcata Grabau, Rhynchospira preafomosa Grabau,

Pentamerus pes-ovis 'Whitfield, Camarotoechia hydraulics (W hitfield)

Ulrich and Bassler are quoted by Foerste (1931, P. 193) as saying the

Greenfield dolomite belongs near the base of the upper half of the

Cayugan,

Kokomo limestone. Foerste (19QU, p. 33) defined the Kokomo at Hopkins, Indiana as consisting of two members, eurypterid beds and an overlying brachiopod bed. Later, at Foerste's suggestion,

Cumings and Shrock (1927, p. 76, 77) confined the formation to the lower of these two. Cumings and Shrock stated that the Kokomo is composed of finely laminated argillaceous limestone lying between the Mississinewa shale below and the Kenneth limestone above. The

Kokomo of Howard and Cass counties, Indiana, is described as gener­ ally gray and brown banded very fine-grained dense and thinly laminated limestone and dolomite.

Where it crops out in Howard and Cass counties, the formation is £0 feet thick. Approximately 20 feet of tan and brown very fine­ grained limestone were observed in cuttings from the Wells Estate well in Tipton County. A sample gap near the surface resulted in an incomplete formation thickness in this well, but 7 or 8 miles to the north feet of Kokomo limestone (nearly all of the type section) is preserved in the Kokomo core, Howard County, Indiana. Eastward to

Allen County near the Indiana-0hio border, 2$ feet of predominantly brown partly porous and sucrosic dolomite is present in the Wakeland well. A few feet of very fine-grained light tan limestone of questionable affinity is present above the dolomite and below brown 9 3 fine-grained very sandy and glauconitic Devonian limestone. The 25 feet of dolomite strongly resembles the Greenfield of Ohio, and also

is similar to the Kokomo. This observation fits in with Cumings and

Shrock's (1930, p. 18U-189) correlation of 3$ feet of beds near

Fort Wayne, Indiana with the Greenfield formation. Shaver (1962,

p . 28) says the correlation of these beds is in doubt as their sandy

dolomite lithology is also characteristic of basal Devonian rocks in

northern Indiana,

The Kokomo beds lie on the Liston Creek limestone or a facies

thereof, and are overlain by the Kenneth Limestone Devonian (?) or by strata of undoubted Devonian age according to Shaver (1962, p. 27).

There is much support for an unconformity between the Kokomo and the

overlying Kenneth limestone, but some geologists, including Shaver,

doubt earlier concepts of a disconformable lower contact. However a

disconformity exists between the Greenfield (Kokomo equivalent) and

Peebles at outcrops in southwestern Ohio.

The Kokomo formation of Indiana cannot at present be assigned

a definite age. A key area exists near Fort Wayne, Allen County,

where Cumings and Shrock (1930) identified well cuttings with Kokomo

characteristics to be Cayugan Greenfield dolomite. Pinsak (1961,

p. Ul) suggests that similar dolomites exposed in the May Stone and

Sand Incorporated quarry on the southwestern edge of Fort Wayne

correlate with the Devonian Detroit River Group of the Michigan

Basin. Although the writer finds the beds in the Fort Wayne area

are lithologically equivalent to the Greenfield of Ohio, lack of

paleontological evidence and the unexplained presence of the fine-grained sand indicate a need for further investigation.

Williamsport sandstone. The name was originally applied by

Eeger (192U) to sandstone considered to be a subdivision of the

Bloomsburg Shale. The name is taken from Williamsport, Grant County,

West Virginia, although no detailed section was measured at the type locality to fix the exact position of these beds with respect to the

Wills Creek or Niagaran strata. The sandstone was redefined by

Woodward (19hl, p. 50), because the distinctive character of the beds does not fit the red facies of the true Bloomsburg. As thus interpreted it forms the basal part of tne Cayugan along the outcrop belt in Pendleton, Grant, Hardy, Hampshire, and Mineral counties,

West Virginia.

The Williamsport is typically a gray to greenish-brown medium textu red quartzose sandstone occurring in medium to th ick b ed s. Out­ crops in Mineral, Grant, and Pendleton counties usually show 3 to I4 feet of massive beds at the base and top with thin-bedded argillaceous sandstones or shales in the middle part. The subquartzitic character , of the Williamsport in Pendleton County causes it to be a ridgemaker.

At certain Mineral County outcrops the siliceous bonding decreases and th e sandstone i s o n ly m oderately hard (Woodward, 19U1, p . 1^1) •

In the West Virginia wells studied, rocks at the approximate

stratigraphic position of the Williamsport are light to dark brownish- gray fine- and medium-grained sandstones, with dolomitic or siliceous

cement. D ifficulties are encountered in tracing the Williamsport westward from the type locality in Grant County. 'Wells in Randolph and Preston counties show shale and siltstone in the upper McKenzie. Apparently the subsurface Williamsport represents the uppermost or

youngest phase of a recurring clastic cycle that was intermittently

present during deposition of the underlying McKenzie; but is this

the same clastic unit named Williamsport on the outcrop? To the

south in the Damron w e ll in G reenb rier County the W illiam sport occurs

about UO feet below Cayugan anhydrite and at a transition point be­

tween dolomite above and probable McKenzie, limestone below. In the

Dean well, 20 miles to the northwest, only a few feet o f sandy

dolomite represent supposed VJilliamsport beds. In the Arrington and

band Hills wells in Mason and Wood counties, western V/est Virginia,

there are in addition to beds called Williamsport one or more thin

sandstones in the overlying V /ills Creek. The upper p a rt o f the

McKenzie in the36 two wells is relatively free of sandy beds that

might be confused with the Williamsport.

The problem results from the fact that the Cayugan-h'iagaran

boundary is usually placed at the base of the first sandstone below

the Clifton Forge sandstone in eastern V/est Virginia, and at the

first sandstone below the 0ri3kany (Ridgely) in western V/est Virginia

If the ’Williamsport is not a continuous widespread sandstone it is

useless for defining the lover boundary of the V/ills Creek or the

upper boundary of the McKenzie in the subsurface, bandy beds in the

licKenzie are probably m isidentifled as ’Williamsport at times. A

possible example is the sandy interval in the Foulke well on Plate II

Note the abnormally thin Lockport that results from choosing the

upper contact at the base of sandstone that is questionably identi­

fied as ’Williamsport. Chen (196U, p. b) doubts that the ’Williamsport sandstone has a definite stratigraphic position. On the basis of recently measured sections, he finds that the Wills Creek Formation is only 20 feet thick in one section but more than 300 feet in another if one accepts the so-called Williamsport sandstone as the lower contact, Chen believes several thin and local sandstones occur in the Cayugan and therefore the Williamsport is not qualified to be ranked as a formation or even as a member of the Wills Creek.

On the basis of information from a few wells the writer believes that some sandstone at the Williamsport position is continuous but over a more limited area than previously reported. Local sandstones in both Cayugan and Niagaran strata complicate attempts to find the areal extent or prove the continuity of such a sandstone. Very likely the Williamsport should be classified as a member of the W ills

Creek formation pending further investigation.

Outcrops of the Williamsport typically range between 20 and

30 feet in thickness. Subsurface thicknesses are harder to establish.

Generally !? to 15> feet is present in wells from Randolph, Fayette,

H arrison, Pocahontas, Kanawha, and Hardy c o u n tie s. Only 2 or 3 f e e t was found present in the Sand H ills well, Wood County, but Travis reports a thickness of 90 feet in the Dean well, Greenbrier County.

This sandstone thins to the west and is absent in eastern Ohio and

Kentucky. These beds may have been a contributing source for the silty residue which is particularly noticeable in the basal part of the Greenfield formation in eastern Ohio.

The Williamsport beds are reported to rest upon the calcareous 97 shales or limestones of the McKenzie, and are overlain by the Wills

Creek limestone.

West and south of east-central Maryland, the red Bloomsburg

thins and is replaced by marine beds. In the vicinity of Homney and

Moorefield, Hampshire County, West Virginia, beds that have been

called Williamsport occupy the position of the thin Bloomsburg string­

ers, But equivalence to part of the Bloomsburg is no help in corre­

lating the Williamsport with the standard section, since the Blooms­ burg facies are known to occupy different stratigraphic levels (Wood­ ward, 19U1, p, 17U). The Cayugan age of the Williamsport is tenta­

tive and depends on the rare occurrence of fossils that include

Leperditia altaj Leperditia elongata var, w illsensis, and a species

of Fterinea. The supposed persistence of these strata near the

base of the Cayugan Wills Creek formation as noted in the literature

is also used as a basis for age determination.

W ills Creek Formation

In eastern V/est Virginia, beds above the Williamsport sand­

stone and below the Tonoloway limestone were identified by Woodward

(I9I4I, p. 175) with the Wills Creek limestone of Maryland. In

Maryland the formation derives its name from Wills Creek at Cumber­

land, where strata were formerly exposed along the creek at the cement

works east of the narrows. The name was first mentioned in U. S.

Geological Survey Folio 179* The outcrop along the Baltimore and Ohio

Railroad near Pinto, Maryland, may be considered the true type local­

ity, although this name was preoccupied and could not be used. 98

In its type locality the Wills Creek consists of interbedded calcareous shale, calcareous mudrock, and argillaceous limestone, with several beds of sandstone. Outcrops in Mineral County, West

Virginia are described as medium gray calcareous shale and platy argillaceous limestone.

In the subsurface the Wills Creek consists mostly of dolomite, particularly in the central and western parts of West

Virginia. Wells in Preston, Greenbrier, and Fayette counties show lim esto n e interbedded w ith th e d o lo m ite. The beds show medium to dark shades of gray, gray-brown, and brown, and tend to be fine­ grained. They are generally more argillaceous in the northern part of the state and in some western counties. In deep wells in Preston,

Randolph, Harrison, and Wood counties there are distinct shale units which are believed to have important correlation value. These shales are similar to the greenish-gray pyritic shales in the lower part of

the Tymochtee formation of Ohio. Also present in deep wells is the mineral anhydrite. It usually occurs as a fine-textured gray to brown material which is hard to detect in the very fine well cuttings

that result from air drilling. Sometimes coarse white crystals are •

present. Although anhydrite and salt are reported from some deep wells, only a few salt-crystal impressions occur in surface exposures

of the V/ills Creek.

At the West Virginia outcrop the Wills Creek limestone ranges

from a reported maximum thickness of feet in Hardy County to $h ■

feet at Alvon, Greenbrier County. Chen (1961;, p. 8) reports a

minimum thickness of 20 feet if the Williamsport sandstone is used to 9 9 define the lower boundary. Other thickness figures are 220 and 2|?0

feet in Pendleton County and 320 and 3!?0 feet in Grant County (Wood­ ward, 19U1, p. 202), Subsurface data yield few reliable thicknesses because of the difficulty of distinguishing the upper contact in well

cuttings. The Wills Creek formation is probably present in the sub­

surface of eastern Ohio and Kentucky, a ll of West Virginia, and the

western half of Pennsylvania, In addition the formation crops out in

Pennsylvania, Maryland, Virginia, and West Virginia.

The Wills Creek formation is overlain by the Tonoloway and

underlain by the Williamsport sandstone or the McKenzie formation in

West Virginia, Sedimentation was undoubtedly continuous in this part

of the basin producing conformable contacts. As described on an

earlier page, the presently accepted lower boundary with the

Williamsport formation is fairly distinct. Where the latter is very

thin or absent, so that the Wills Creek rests essentially on Niagaran

carbonates, the contact is difficult to pick. The Lockport dolomites

and the McKenzie limestones grade upward into calcareous shale, impure

limestone, and dolomite of the Wills Creek formation in such manner

that no satisfactory separation can be made in some West Virginia

wells, Travis (1962, p. 1*3) says that insoluble residues were helpful

in picking the contact in the Gribble well> Harrison County, and in

the United Fuel Gas - Fee well, Clay County, In the latter, the

tested Lockport interval yielded an average of i;3 percent insoluble

residue, compared to 61 percent for the tested Wills Creek-Williams­

port interval. The Gribble well yielded less definitive results and 100 on a percent basis of insoluble residues neither well correlates with the Sand H ills well or with each other.

The upper contact with the Tonoloway is even more difficult to discern in well cuttings and is rarely available from V/est

Virginia well records. According to Woodward (19hl, p. 182), the upper boundary was difficult to determine even in the original definition. No natural boundary exists. As a rule the Wills Creek limestones are more argillaceous than the thin-bedded laminated

Tonoloway limestones above. Weathered exposures show this difference by a rather complete weathering of the Wills Creek to an arenaceous residue that produces a grayish soil whereas the Tonoloway breaks into flat platy fragments that eventually produce an orange colored soil. The insoluble-residue method, in spite of shortcomings, was useful to Travis in locating the lower contact, and it might also prove helpful in estimating the Wills Creek-Tonoloway boundary.

The V/ills Creek formation is the lowermost limestone in the

Cayugan of 'West Virginia. On the basis of position, fauna, and lithology, V/oodward (19Ul, p. 20U) correlates it broadly with the

Camillus shale (limestone) of western and central New York. He further.states that it may be represented in the lowest part of the

Greenfield dolomite of Ohio, In the band Hills well, the lower 30 feet of the V/ills Creek is equivalent to strata in the upper part of the Greenfield whereas the upper nine-tenths of the Wills Creek is stratigraphically equivalent to the lower half of the Tymochtee formation in Ohio. Criteria establishing this equivalence are the presence o f some ty p ic a l G reenfield str a ta and the occurrence of the 101

Salina-Tymochtee "C" shale unit in the basal part of the W ills Creek.

Both the gamma-ray-neutron log and sample cuttings show this distinc­ tive shale unit. On this basis, correlation of the Wills Creek is made w ith the S a lin a Group in Ohio and M ichigan.

Sixteen species representing seven genera of ostracods, among which Leperditia appears to be most abundant, have been found in the

W ills Creek formation. A few eurypterids have been reported at Cumber­ land, Maryland, and in Hardy County, V/est Virginia. Also present are some bryozoans and the brachiopods Camarotoechia litchfleldensis,

Chonetes? interstriata Hall, Howelie11a corallinensis (Grabau), H. vanuxemi (Hall), Lingula sp., and Uncinulus obsolescens Swartz. A species of the pelecypod Actinopterella, and a cyathophylloid coral have also been reported from this formation. These fossils do not give conclusive evidence for an exact correlation of the Wills Creek, nor are they useful for delineating the Wills Creek-'fonoloway boundary.

Tymochtee Formation

In 1873 Winchell (p. 633) named 2k feet of thin-bedded shaly dolomite along Tymochtee Creek in northern Wyandot County, Ohio, the

Tymochtee slate. In the Bass Islands formation proposed by Lane and others (1907, p. £5U) the thin-bedded dolomite believed to intervene between the G reen field and B ut-in-B ay members was c a lle d the

Tymochtee member. The uncertainty resulted from the absence of exposed upper and lower contacts, btauffer (1908) was the first

to use the name Tymochtee formation. He applied the term to 102 approximately 20 feet of thin-bedded compact drab limestone u n derlying

the Sylvania sandstone in Lucas County. In 1951 (p. 10) Ehlers,

Stumm, and Kesling placed the Tymochtee beds in the Salina Group.

H iller (1955, P. 37) identified the Greenfield-Tymochtee contact in

three quarries in southwestern Ohio. At present the upper contact

of the Tymochtee with the Bass Islands is known only in the subsurface.

Outcrops of the Tymochtee occur from Adams County, southern Ohio,

northward through Logan and Wyandot counties to Lake Erie and west­

ward across the northern part of the state.

The Tymochtee consists of predominantly gray fine-grained

dense thin-bedded dolomite that is commonly argillaceous and shaly.

Carbonaceous laminae and shale partings occur frequently, as do mud-

cracked layers, especially in the upper part. Miller (1955, p. 8U)

classified variations within the xymochtee into five lithologic

types. In addition to these he found nontypical Tymochtee strata

in two Fayette County quarries. The five main lithologic types or

lithofacies are:

No. 1 (50 percent) Dolomite, gray-brown and in 1 to 6 inch layers; commonly banded and separated by many b lack sh a ly p a rtin g s; ty p ic a l Tymochtee.

No. 2 ( 8 p ercen t) D olom ite, medium gray to dark yellow-brown; in thick layers 18 to 26 inches; vuggy and contains stromatoporoids.

No. 3 ( 6 p ercen t) S h a le, d o lo m itic and medium gray to greenish-gray with silty residue; probably equiva­ lent to Salina B and C shale units in Michigan b a sin .

No. U (20 p ercen t) D olom ite, a r g illa c e o u s medium to light gray and very dense; fractures evenly and shows conspicuous mottling. 103

No, $ (16 percent) Dolomite, argillaceous light olive- gray to medium gray; m assive to thin-bedded w ith uneven bending or laminations; some layers are brecciated and bituminous residue occurs at certain levels.

The lithology of the Tymochtee in well cuttings can be roughly compared to the types described by H iller (19£5), although nontypical lithology was encountered also. These types apparently do not have a fixed stratigraphic position, except for Type 3 which

occurs in the lower part of the formation. Subsurface Tymochtee

strata are buff, tan, gray, gray-brown, and brown. They are usually

dolomite or calcareous dolomite but vary from argillaceous dolomite

to dolomitic shale. The formation contains bedded white anhydrite,

oolitic dolomite, and occasional porous zones. The well cuttings are

typically dense, with a dull surface that suggests the presence of

argillaceous matter.

In the Michigan basin, Landes (19U£) subdivided the sub­

surface Salina formation into Units "A” through "H" in ascending

order on the basis of lithology and extensive salt layers. In

tracing these units into northern Ohio, Ulteig (1963, P* 2$) co rre­

lates units "B" through "G" with the Tymochtee formation. The upper­

most bedded anhydrite constitutes the top of the Tymochtee in his

report. Only two or three of the eight Salina units traced into

northern Ohio from the Michigan basin can be identified in southern

Ohio, because salt beds and most of the shale which form the major

basis of this subdivision are absent. In southern Ohio, therefore,

the lettered unit divisions of the Salina are not applicable. How­

ever, the shale in the nBM and "Cn unit (Type 3 lithology of Miller) 10U has excellent correlation properties* Ulteig (1963, p . 29) claim s that it can be identified throughout Michigan, Ontario, and Ohio, and into Pennsylvania and New Xork. He believes the "C" shale^ represents a westward tongue of the Vernon shale. The writer extends the area in which this unit can be identified into southern Ohio, parts of eastern Kentucky, and at least the western part of V/est Virginia.

M ille r (19!?5, p . 176-79) has d escrib ed more than 80 f e e t of

Tymochtee strata at Sugar Creek Stone quarry in Fayette County, Ohio.

Approximately U7 feet of typical Tymochtee strata are exposed at

Plum Run Stone quarry, Adams County. The formation can be traced in the subsurface as far south as Johnson and Martin counties,

Kentucky, In the James well, Martin County, it is 200 feet thick.

Eastward from Pike and Licking counties, Ohio, into West Virginia

(Plates I and II) the Tymochtee increases in thickness to about 800 feet as it passes laterally into most of the Mills Creek and the

Tonoloway formations. In western Pennsylvania, Ulteig (1963, pi. 8) indicates more than 700 feet of Tymochtee strata are penetrated by a well in Mercer County.

The lower'Tymochtee contact with the Greenfield is conformable.

In many western Ohio wells the Tymochtee is overlain by the Raisin

River (Bass Islands) dolomite'. The Tymochtee is overstepped by the

Ohio shale at Plum Run quarry in northern Adams County and in other areas south of Fayette County, Ohio. In the subsurface of eastern

^The Galina "C" unit of Ulteig comprises most of this far ranging marker bed, but the upper part of the "E" unit is also present; for simplification both are included in the term "C” shale unit. 10$

Ohio, basal beds of the Helderberg overlie the Tymochtee.

The lower lim it of the Tymochtee is placed by Ulteig (1963, p, 17) below the lowest salt unit or its anhydrite equivalent in northern Ohio. Similarly in central Ohio and some parts of southern

Ohio this contact can be recognized by the unique character of the gamma-ray-neutron log at the base of the Tymochtee or the Salina "B" unit. Where both salt and anhydrite are absent in southern Ohio, some lithologic differences and corresponding gamma-ray-neutron characteristics are s till present. Both the "C11 unit and upper part of the "B" unit of the Salina or the basal Tyjnochtee contain dolomitic shale and argillaceous dolomite with distinctive green coloration in addition to the predominant gray. The lowest of these shales or shaly dolomites may occur as low as 10 to 2$ feet above the Green- field-Tymochtee contact. In western Ohio there is a change from a dull argillaceous gray or gray-brown dolomite above to rich brown partly crystalline (sucrosic) dolomite below. Tymochtee well cuttings also tend to occur in thinner chips than cuttings from the

Greenfield.

The sparingly fossiliferous nature of the Tymochtee has not been very helpful in obtaining precise correlations. Foerste (1935, p. 186) notes that the Tymochtee contains two species mentioned as

characteristic of the underlying Greenfield, namely the brachiopod

Hindella rostralis and the ostracod Leperditia ohioensis. Both

species are smaller than those found in the Greenfield. Additional

fossils found by Miller (1955, P. 130) included Pentamerus pes-ovis

Whitfield and the cephalods Hexameroceras sp. and Michelinoceras (?) 106 sp. He also found some unidentified scolecodonts and poorly preserved pelecypods. The Eurypterids, Surypterus ornatus Leutze and

Pterygotus perryensis Leutze are listed by Ailing and Briggs (1961, p . 5 3 0 ).

Landes (19U5) has suggested Unit ”0" of the Salina formation is represented by the Pointe aux Chenes shale at outcrops on the northern peninsula of Michigan. Ehlers and Kesling (1962, p. 11) suggest the lower part of the Pointe aux Chenes is equivalent to the

Salina "C" and "E" units. If this correlation is confirmed, then the

Pointe aux Chenes formation is equivalent to part of the Tymochtee.

Tl\e Pointe aux Chenes is correlated with the Bertie waterlime in western New York state by Ehlers and Kesling (1962, p. 11) on the basis of a common peculiar fauna that includes Medusaegraptus gramminiformis (Pohlman), Orbiculoidea bertiensis Ruedemann, and

Leperditia scalaris (Jones).

Tonoloway Formation

The Tonoloway formation is the name given strata exposed at

Tonoloway Ridge along Cacapon River near Rock Ford, Morgan County,

West Virginia. According to Swartz (1923, p. U3) the name was first used in the United States Geological Survey's Folio No. 179, 1912 and the beds exposed along the Baltimore and Ohio Railroad at Pinto,

Maryland, should be considered the type area because this section is complete and accessible.

Woodward (19U1, p. 209) differentiates 3 members of the

Tonoloway, The upper and lower members are composed m ainly o f dark gray calcareous shale and thin-bedded laminated clayey limestone. At some localities a 3- to 5 inch sandstone occurs at the base of the upper member. The middle member consists of black limestone, rubbly irregularly bedded dark blue limestone, and scattered beds of gray rather pure limestone. Chert occurs rarely in the middle member.

The Tonoloway limestone is generally fine-grained, although some medium-grained beds have been described. At outcrops the typical gray argillaceous limestone of this formation weathers light or very light gray.,

The Preston County well, UO miles southwest of the Pinto outcrop, shows strata that fit Woodward's threefold subdivision.

The upper Tonoloway (195 feet thick) consists predominantly of gray shaly limestone with a few feet of very fine-grained shaly and silty dolomite near the top. The middle Tonoloway (115 feet) is composed of dark brown to gray-brown limestone that is nearly litho­ graphic in places. The lower Tonoloway (estimated at 273 feet) con­ sists of light, medium and dark gray or gray-black limestone, dolomitic limestone, and dolomite. The dolomite is confined to the lower half. Anhydrite, which occurs in thin beds at various levels throughout most of the Tonoloway, is most common in the basal part of the formation. A similar succession of Tonoloway strata were ob­ served in the Randolph County well, hZ m iles to th e sou th . The two wells are aligned nearly parallel to the depositional strike. About

UO miles west of the Preston County well, only the middle and lower units of the Tonoloway appear to be present in the Gribble well,

Harrison County, according to published sample descriptions by 108

Martens (19U5). Apparently facies change rather than erosion caused the upper unit to be absent, since the Tonoloway-Wills Creek thick­ ness is nearly as great as in the Preston County well and the estimated thickness for the Tonoloway fits the regional pattern quite well. Westward the big change in Tonoloway lithology takes place before the Sand Hills well in Wood County, western West Virginia is reached. Cuttings from this well show that the typical Tonoloway limestone is entirely replaced by dolomite and bedded anhydrite.

The outcrop subdivisions of Woodward no longer apply. In fact the lithology encountered in the Sand Hills well is more readily identifiable with the upper half of the Tymochtee formation in the subsurface of eastern Ohio.

The Tonoloway beds thin westward from 608 feet at Pinto,

Maryland, to estimated thicknesses in West Virginia of feet in the Preston County well, 500 feet in the Gribble well, Harrison

County, and U60 feet in the Sand H ills well, Wood County (Plate I).

The Tonoloway also thins to the southwest, from a maximum of about

820 feet at Mount Union, Huntingdon County, Pennsylvania, to approximately 600 feet in Randolph County, West Virginia. Less than

300 feet of strata are reported near Alvon, Greenbrier County, and less than 100 feet near Bluefield, Mercer County, southern 'West

V ir g in ia .

In West Virginia the Tonoloway formation is overlain by the

Keyser limestone and underlain by the Wills Creek limestone. Avail­

able evidence indicates that both contacts are conformable. The

lower contact with the Wills Creek has already been described. The 109 upper contact is generally indicated in well cuttings by a change from dark brown occasionally cberty Keyser limestone to gray or dark gray argillaceous or shaly Tonoloway limestone below. Bedded anhydrite generally occurs in well cuttings within 20 to £0 feet of the lithologic break that marks the contact.

In the Damron well, Greenbrier County, the contact occurs between d o lo m itic sandstone o f the C lifto n Forge member o f the

Keyser and interbedded limestone and calcareous dolomite of the upper Tonoloway. A sandstone occurs in the Band Hills well at the approximate position of the Clifton Forge, but the contact is placed about 1*0 feet above it, between slighty sandy and pyritic

Helderberg limestones and underlying calcareous dolomites (Bayles,

1956, p. 12), Shearrow (1957, p. 30) used insoluble residues in determining both the Tonoloway-Helderberg and the W ills Creek-

Lockport contacts in this well. Changing lithology in the Keyser apparently requires different criteria for choosing the boundary with the underlying Tonoloway. In one locality the contact is picked at a change from limestone to dolomitej in another locality the change is from cherty or siliceous limestone above to argil­ laceous or shaly limestone below; and in still other localities the base of a sandstone is chosen. Generally speaking the first litho­ logic break above the highest bedded anhydrite is selected as the

Tonoloway-Keyser contact.

Ten species of invertebrate reported from the Tonoloway of

Karyland occur in undoubted Cayugan strata of central Mew York, j However, their range (Swartz, 1923, p. 213) does not permit confident correlations with individual New York formations. On the basis of

stratigraphic position, Woodward (19Ul, p. 2£6) states that lower and middle Tonoloway and part of the upper Tonoloway are represented to

the northeast by Bloomsburg shale, whereas the topmost Tonoloway ex­

tends eastward relatively unchanged into shale and limestone exposed

along the Delaware River, On the evidence of related species of

Leperditia, Camarotoechia, Hindella, Rhynehospira, and Gchuohertella

(Schellwienella) 'Woodward (19Ul, p. 2^7) correlates the Tonoloway

with the Greenfield of Ohio.

Related species of three of the five genera of Leperditia,

Hindella, and Behueherte11a used by Woodward to correlate with the

Greenfield are found in the overlying Tymochtee (Miller, p. 130) or

continue into the Bass Islands dolomite above the Tymochtee (Foerste,

1935, P« 186). The Tymochtee has furnished a meager number of

invertebrate species, but it seems likely that these beds will

eventually yield other species that are presently found in Tonoloway

and Greenfield strata. The writer finds the Tonoloway is strati-

graphically equivalent to the upper part of the Tymochtee formation.

It might be restated that stratigraphic equivalence in this report

does not imply age correlation.

Raisin River Formation

The genetic relationship of the Greenfield, Tymochtee and

Raisin River leads the writer to place all three in the same group.

Accordingly the Raisin River is placed in the Galina Group and the

term Bass Islands is elim inated as a group name. I ll

The term Bass Islands was used by Lane and others (1908, p* 55U). This group of rocks as recently defined occupies the interval between the Salina Group and overlying Devonian sandstone or carbonate strata. The type locality is on the Bass Islands in

Lake Erie north of Sandusky, Ohio. The group was originally divided into the Greenfield, Tymochtee, Put-in-Bay and Rai3in River formations in ascending order. Ehlers, Stumm, and Kesling reclassi­ fied the Greenfield and Tymochtee dolomites as part of the Salina

Group (19^1, P. 10). Ailing and Briggs (1961) doubt the wisdom of

separating the Bass Islands into two formations, because these are not distinctive units in the subsurface and are not exposed in any

one ou tcrop . Summerson (1963, p . 5U) su g g ests th a t the rath er restricted exposures of the brecciated Put-in-Bay are local facies

of the Raisin River formation. The foregoing considerations have

led the majority of present-day geologists to combine the two and refer them to the Bass Islands dolomite. In this report the Raisin t River dolomite is considered to include the Put-in-Eay facies. As

so defined the Raisin River refers to the same strata as the Bass

Islands dolomite used by subsurface geologists.

The R aisin River was named by Lane and oth ers (1908, p . 95U).

Carman (1927, p. U92) considers the type locality to be along the

Raisin River near Monroe in southeastern Michigan, where it is about

200 feet thick.

The formation is generally fine- to very fine-grained

dolomite, dense and sparingly fossiliferous. The color changes as

does the argillaceous content. It is light gray to brownish-gray 112 with occasional yellowish cast, partly laminated dolomite. The form ation occurs in m assive or in th in to medium b ed s. Surface exposures of the Raisin River are present in Lucas, Sandusky, Seneca,

Erie and adjacent counties in northern Ohio. To the south, outcrops are reported in Delaware, Franklin, Fayette, Pickaway, and Madison counties. The writer sampled rocks in the last two counties and crushed samples, along with samples from the Bass Islands in Lake

Erie for comparison with each other and with well cuttings. By comparison with this typical lithology it was possible for the writer to identify the Raisin River in the subsurface of Wayne,

Coshocton and Ross counties, the eastern part of Pike and Licking counties,and in bcioto County, Ohio. Carman (1995, p. 71) reports

6 feet of Raisin River dolomite in a core from a test boring south

of Chillicothe, Ross County,

Ulteig (1963, p. 26) states ttiat the Pass Islands (itaisin

River) in well cuttings from northeastern Ohio is typically brown

argillaceous calcareous dolomite with occasional anhydrite crystals.

In the Gilmore well, Coshocton County, east-central Ohio, he includes

nontypical brown pelletal limestone, which has characteristics of

the Helderberg, in the Bass Islands. In the Marshall well, Guernsey

County, about 23 miles to the southeast, the same interval is occupied by light brown or medium grayish-brown dolomite, with 10 to 20

percent of interbedded anhydrite. Except for the anhydrite this

lithology more nearly resembles that of the Raisin River at outcrops

in western Ohio. In Pennsylvania (Cate, 1961) bedded anhydrite marks

the top of the Salina. 113

The changeable lithology of carbonate beds at the strati­ graphic position of the Bass Islands and Keyser beds in central and eastern Ohio indicates a complex relationship. Geologists do not acknowledge a significant break between the Silurian and Devonian in the deeper part of the Appalachian basin to the east, but rapid lateral changes in rock type in the vicinity of Coshocton, Muskingum, and eastern Guernsey counties indicate that erosion or a facies change (perhaps both) accounts for the absence of Bass Islands d o lo m ite.

The Bass Islands dolomite apparently occupies a position above the Tymochtee (Salina "B" through *• G**) in the Michigan basin and in northern Ohio, but where most of the shaly material is absent from the Tymochtee in southern Ohio these strata resemble, and in places cannot be differentiated from, the Bass Islands formation,

Well cuttings from various' intervals in the Tymochtee of central

Ohio also resemble Bass Islands Strata. The writer concludes that the Bass Islands formation is partly a facies of the Tymochtee. The basin configuration in Cayugan times may have been such that Bass

Islands strata were deposited in some places while dolomite, anhy­ drite, and salt of the Salina-Tymochtee formations were formed in

other areas.

An excellent section of the Bass Islands (Raisin River and

Put-in-Bay of Carman), nearly 8U feet thick, was exposed in the

Holland quarry, Lucas County, Ohio, according to Carman (1927, p. U91,

U93). The lower 5U feet of this section is now under water. Landes

(19U£) shows that the Bass Islands dolomite thickens from 20 feet in ix u

Fulton County, northwestern Ohio, to a maximum of $10 feet near the center of the Michigan basin. Ulteig (1963, p. 26) reports that the formation thickens to 2$0 feet in the subsurface of eastern Ohio, although the latter thickness includes nontypical beds. Almost due south from the Lucas County quarry, approximately 30 feet of typical strata are present in the Dunlap well, Pickaway Countyj U8 feet in the Wenzel well, Ross County; and 30 or more feet in the Dever well,

Scioto County.

Ailing and Eriggs (1961, p. $2h) and Ulteig (1963, p. 26, fig. 13) indicate that the Bass Islands is truncated below the

Silurian-Devonian unconformity in northern Ohio along a general north-south line from eastern Sandusky County through Huron, Richland,

Knox, and eastern Licking counties. In the area of investigation, the writer estimates the truncated western edge of the Bass Islands extends southward from the eastern part of Madison and Fayette counties along the western side of Ross County, through the middle of Pike County and into northeastern Scioto County. Sparse outcrops in Madison and Pickaway counties and few control wells in the area

to the south where the Bass Islands is not present at the surface give only an approximate zero line.

In west-central Ohio the upper contact of- the Bass Islands with the overlying Oriskany sandstone or Devonian limestone can be detected without difficulty in the subsurface, and at outcrops in the

Madison Stone and Halmar quarries in Madison and Pickaway counties respectively. In eastern Ohio the Bass Islands is absent, and the

Keyser formation, which some geologists consider to be correlative 115 with it, cannot at present be differentiated from similar strata that constitute the rest of the overlying Helderberg group.

The nature o f th e B ass Islands-Tym ochtee c o n ta ct i s unknown at the outcrop, but in the subsurface the contact is apparently conformable. Well cuttings indicate a change from buff and pale- brown vary fine-grained, dense dolomite to an underlying grayer and more argillaceous dolomite with associated anhydrite. The anhydrite may be absent in parts of southern Ohio and can be considered diagnostic only in northern Ohio, Pennsylvania, and Michigan.

Carman (1927, P. U93) listed 13 fossil forms identified from the Bass Islands dolomite but without specific identification because of poor preservation. Ailing and Briggs (1961, p. 529-538) list 21 species from the Bass Islands strata of Ohio and Michigan. Some of the more abundant or distinctive species are the ostracod Leperditia alta; the eurypterid Srieopterus microphthalmus eriensis (Whitfieldj the brachiopods Howellella ohioensis (Grabau), Schuchertella inter- striata (Hall), and W hitfieldella prosseri Grabau; and the pelecypods

Goniophora dubia (Hall) and Pterinea lanii Grabau. One or two of these species are shared with the Greenfield, Tymochtee, Kokomo,

Tonoloway, Wills Creek or Akron formations, but none is useful in correlating with a particular formation in the Salina group of New

York state. Different groups of fossils are found in each area of

Salina rocks. Perhaps poor preservation of nearly identical forms does not allow accurate specific or generic identification (Leutze,

1959), or perhaps there has been some confusion of youthful and mature forms. Ailing and Briggs (1961, p. 528) suggest that some 116 of the difficulty may lie in the desire to recognize minute differ­ ences rather than to find sim ilarities among the fauna.

Stratigraphic Relations within the Salina Group

Strata resembling the Greenfield occur at intervals in the lower part of the Tymochtee in some wells, and in others the lower part of the Greenfield grades imperceptibly into the underlying

Lockport. In northern Ohio the lower contact of the Greenfield is placed at the base of the lowest anhydrite. Typical Greenfield continues below the lowest anhydrite in some southwestern Ohio wells.

In other wells, no evaporites are present in the entire Cayugan section. Variation in Greenfield lithology including lack of anhydrite, may result in differences of opinion concerning both the lower and upper contact although approximate position of the Green­ field below the "C" shale unit should prevent any large error in choosing the upper contact.

Because neither contact of the Tymochtee is exposed in the type area, the ldjnits of this formation in the subsurface are largely a matter of interpretation. On the meager data from one well in the township adjoining the one where the type section occurs in Wyandot County, the writer believes that the typical shaly. beds of the Tymochtee do not continue very deep below the surface.

Geologists have speculated on,the possibility that the type Tymochtee is the "C” shale unit of the Galina. A gamma-ray-neutron log on a well or ’’strat" test in the immediate vicinity of the type section would solve this dilemma. The absence of exposures showing the 1 1 7 upper and lower contacts in the type area has led subsurface geolo­ gists including Ulteig (1963) to use a broad interpretation in

delimiting the boundaries of this formation. The uppermost shaly unit in the Cayugan beds (Unit "G" of the Salina in the Michigan basin and northern Ohio subsurface) is interpreted as constituting

the top of the Tymochtee in the subsurface. The lower boundary is at the base of the salt in the "B" unit of the Galina formation in northern Ohio and Michigan. Where the salt is absent the base of

the "B" unit occurs where a thin shale overlies a split anhydrite bed. The Tymochtee as thus defined is characterized by a diverse

littology which includes evaporite beds, dolomite, argillaceous

dolomite, and dolomitic shale. The lim its of the formation appear

to be clear-cut in,northern Ohio and Michigan. It should be

emphasized, however, that even in central and northern Ohio where the

contacts are well defined, relatively "clean" dolomite occurs in many wells at various intervals between the "C" and "G" units. Much

of this "clean" dolomite resembles the Bass Islands dolomite on the

ou tcrop .

The Tymochtee thins to the south and southwest, probably

more as a result of non-deposition than through erosion. The "C"

shale unit persists to the south, but the shale and shaly dolomite

in the "F" and "G" units in northern Ohio do not. The absence of the

upper shaly dolomite causes the Tymochtee (?) strata overlying the

"C" shale unit to be gradational with typical Bass Islands lithology.

In wells in Pike, Ross, and Scioto counties these nontypical

Tymochtee (?) beds grade imperceptibly upward into tho Bass Islands, 118 so £hat it is difficult to pick a- contact other than at the top of the "C" shale unit. A detailed analysis of this interval (insoluble residue, petrographic study) is required. For the time being, the writer prefers to classify most of the beds overlying the Tymochtee

••C" shale unit as a nontypical facies of the Tymochtee.

Only the uppermost beds of Cayugan dolomite are classified in the Bass Islands formation in southern Ohio, bass Islands strata are absent to the east in the vicinity of the Ohio-West Virginia border, where sedimentation generally is considered to have been continuous. Bass Islands lithology fauna represents a hypersaline environment, which also existed during deposition of Tymochtee and

Greenfield sediments. The Bass Islands is considered to be partly a facies of the broadly defined Tymochtee foimation (Saline nBn through "G”) and is equivalent to the upper part of the Tonoloway of

West Virginia. Other geologists (Cate, 1961; Ulteig, 1963) have suggested an equivalence with the Keyser formation. The lower part of the Keyser is now accepted as Silurian (Berdan, 196U, p. 16, 17). The writer believes that the period of nearly normal marine sedimentation represented by the Keyser beds was contemporaneous with an erosional interval in parts of Ohio.

Keyser Limestone

Much controversy has surrounded the age and correlation of the Keyser formation. In the past most geologists have classified it in the Kelderberg group and considered it the oldest Devonian formation in West Virginia and Maryland. However, in Pennsylvania it 119 occupies a position at the top of the Silurian column. Recent evidenoa substantiates the occurrence of the Siluro-Devonian boundary within

the formation. Since the lower part of the Keyser is Silurian and because some geologists think it is equivalent to the Bass Islands, a discussion of this formation is included here.

The Keyser limestone is named from Keyser, Mineral County,

West Virginia, where it is almost completely exposed in quarries on

the ea stern edge o f the c i t y (Woodward, 19U3, p . 3 8 ). The form ation

extends southwestward from Columbia County, east-central Pennsylvania, across Maryland into eastern West Virginia and western Virginia.

Typically the Keyser is a blue to dark-gray limestone, mainly massive and nodular below and more shaly and thin-bedded above. A few strata contain chert, and lenses of pure crinoidal or crystalline

limestone are scattered throughout. A thin shale member near the middle of the formation gradually thickens southward to the latitude

of Pendleton County, where it attains its maximum development. This

is the Big Mountain shale, from Big Mountain in the Smoke Hole

settlement. Southward into Greenbrier County, West Virginia, and

Alleghany County, Virginia, this shale and the lower Keyser limestone

give way to the Clifton Forge sandstone, which occupies most of the

Keyser stratigraphic position from James River southward to south­

western Virginia. The Big Mountain shale and the Clifton Forge sand­

stone are considered members of the Keyser.

Two wells in Preston and Randolph counties show lithology and

thicknesses that compare favorably with the typical Keyser at the out-

crop in Grant and adjacent counties. In the Preston County well the 120 formation is divided into an upper shaly unit and a predominantly massive dark gray or brown cherty limestone that is silty or shaly in places. The upper unit is approximately 125 feet thick, this figure including the 20 to 30 feet of shale and limestone at the base that probably represents the Big Mountain shale. The lower unit is 150 feet thick.

Different lithology exists in the Damron well, Greenbrier

County. Here the basal part of the formation consists of 25 feet of tan dolomitic sandstone with some brown and black stains. This is the Clifton Forge member. It is overlain by 85 feet of gray or gray-brown fine-grained partly sandy limestone. Above this is 5 feet of sandstone which may be a tongue of the thicker Clifton Forge strata to the east. The rest of the overlying Keyser consists of tan and gray partly sandy limestone which may total 250 feet or more in thickness. (This figure is a rough estimate since the contact w ith the o v erly in g Coeyman lim esto n e i s g r a d a tio n a l.) The Big

Mountain shale member is missing from the Damron w ell. Keyser lithology, consisting of tan and brown partly crinoidal limestone, is recognizable in cuttings from the interval overlying the Tonoloway formation in wells in Mason and Wood counties, western West Virginia.

Unfortunately, reasonable estimates of thickness cannot be obtained in these« counties as the Keyser cannot be separated from the overlying formations in the Helderberg group.

Maximum outcrop thickness of the Keyser beds occurs near the type locality, where the formation is fiearly 300 feet thick. It thins toward the western part of the state. Thicknesses of 250-275 feet 121 are reported for Pendleton and Grant counties. Woodward (19U3, p. 155, l£6) gives a thickness of 177 feet for the Gribble well, Harrison

County, and 12$ feet as an average for various Kanawha County w ells.

His Keyser and Helderberg isopachs (19U3, p. 39 and 86) indicate 100 to 1$0 feet in eastern Ohio, with a possible thicker section of these beds along a northwest-trending channel cutting through northern Ohio called the Michigan trough.

The lower contact of the Keyser is marked by a change from the thin-bedded limestones of the Tonoloway to the knobby somewhat more crystalline beds of the Keyser, This contact is somewhat easier to choose at outcrops than from well cuttings. The upper contact with the Coeymans limestone is so indistinct at many exposures that c r i t i c a l f o s s i l s may be required to e s ta b lis h i t (V/oodward, 1 9k3, p. U6). Except in the wells described earlier in Pendleton and

Randolph counties the writer encountered similar difficulty in picking the upper contact in the subsurface. Evidence from diagnostic fossils is unavailable.

Two distinct faunal zones have been recognized in the Keyser of Maryland, Pennsylvania, West Virginia, and Virginia. An upper

Favosites helderbergiae zone corresponds to the upper shaly limestone, and a lower Chonetes jerseyensis zone corresponds roughly to the lower nodular limestone. In the Virginias the Big Mountain shale occurs near the top of this lower zone.

On the basis of similar lithologic character and faunal resemblances, Woodward (19U3, p. 63) concludes that the lower nodular

limestone (Chonetes jerseyensis zone) correlates with the Decker Ferry limestone of eastern Pennsylvania, which by faunal evidence is correlative with the Cobleskill limestone of the type New York section. Berdan (196U, p. 16, 17) shows that the presence of the coral Cystihalysites in Cobleskill, Decker, and lower Keyser beds indicates a Silurian age. Boucot (1957; I960, p. 291) states that

the upper part of the Keyser limestone is Lower Devonian on the basis of brachiopods. Thus the Siluro-Devonian boundary is placed between the lower nodular limestone (Chonetes jerseyensis zone) and

the upper shaly limestone (Favosites helderbergiae zone). Within a

limited area in west-central Virginia and east-central West Virginia,

the Big kountain shale can aid the subsurface geologist in picking

the boundary between the Silurian and the Devonian. CONCLUSIONS AND GEOLOGIC HISTORY

The following conclusions were reached concerning the stratigraphic relations of the Silurian rocks investigated and the history they record. In this section w ill be found full or partial answers to the questions posed at the beginning of the paper (pages

8 andLO).

Medina group. The Brassfield limestone and Plum Creek shale are traced northward by means of well cuttings from the type area in

Kadison County, Kentucky, to Sandusky County, Ohio, where these formations correspond to the Manitoulin dolomite and Cabot Head shale across Lake Erie in Ontario. The Brassfield thickens eastward from the outcrop in southwestern Ohio to wells in south-central Ohio, where the carbonate strata of this formation and the shale of the overlying Cabot Head inter tongue with the " Clinton sands.** Farther east in West Virginia these sands merge into the upper part of the

Tuscarora formation.

Beds formerly assigned to the upper part of the Brassfield

in Ohio and Kentucky, which result in extremely thick sections of the

Brassfield as measured by other geologists, including Perry (1962),

probably co n ta in the Oldham and Plum Creek form ation s.

The Clinton sands of Ohio are of Albi'on age. Basal sands in

the Rose Hill formation (Cacapon division) appear to be part of the

123 12k same eastward-thickening clastic wedge that gave rise to the Clinton sands* These sands in West Virginia occupy the approximate position o f the Dayton and Oldham form ations and are b e lie v e d to be o f Lower

Niagaran age.

The Brassfield-Cabot Head sediments represent the most extensive flooding during the Silurian. The Brassfield seas extended from the Tuscarora deltas and beaches in West Virginia and along the

state lines of Ohio and Pennsylvania, as shown by Yeakel (1962, fig . 17), westward to the Qzarks, northward into Ontario, and south­ ward into northern Alabama and M ississippi (Preeman, 19^1, p. 8).

Oolitic hematite beds formed toward the end of Brassfield times and similar deposits occurred in the Clinton. Hunter (1962, p. 199)

explains this release of iron into the sea as a result of low relief

and increased intensity of weathering on exposed igneous or low-

grade metamorphic rocks.

Clinton group. The Oldham limestone and Lulbegrud^ clay,

which crop out in east-central Kentucky, are present in the sub­

surface of southern Ohio. These beds have previously been misidenti-

fied and placed in the upper part of the Brassfield formation. In

Pike, Jackson, and northern Scioto counties, the Oldham and Lulbegrud

beds are readily detected by the use of well cuttings and gamma-ray-

neutron logs. Although present in adjacent counties, these formations

are difficult to separate from the underlying Cabot Head-Brassfield

sequence. They thin and are absent to the west and northwest in

Ohio, and change to a clastic facies eastward into West Virginia,

The overlying Dayton formation has a fairly consistent lithology and 12$

thickness, which make it an excellent Mmarker" bed. The distinctive

lithology of the Dayton formation can be traced over a somewhat

larger area than the Lulbegrud and Oldham.

The E still shale of Ohio and Kentucky was traced into the

Osgood formation of Indiana, and the Hose H ill formation of West

Virginia (excluding the Cacapon division). The Bisher formation

of southwestern Ohio is probably equivalent to the Springfield and

Euphamia formations of western Ohio; the Kississinewa shale of

Indiana; the upper part of the Clinton shale in the subsurface of

eastern Ohio; and the Keefer sandstone and Rochester shale of West

Virginia, The Clinton shale of eastern Ohio consists of heterogeneous

rocks that can be traced into the argillaceous dolomite and shale of

the E still and overlying Bisher formations in southern Ohio and

northeastern Kentucky; and into the Rochester, Keefer, and part of

the underlying Rose Hill formations in West Virginia.

The entire Clinton is represented by approximately 30 feet

of carbonate, rock on the shelf or platform area in northwestern

Ohio. A ll the Clinton formations in the Appalachian basin to the

east thin and lose their identity as they are traced northwestward

onto the platform. A prolonged period of erosion, as suggested by

Rittenhouse (1?U9) is a possibility. However, evidence, shown on the

gamma-ray-neutron log, and environmental conditions as the shelf area

became adapted to support reef life , indicate that nondeposition

(diastems) throughout the Clinton is probably the major reason for

the absence of recognizable formations belonging to the Clinton

group in this area. 126

The presence of hematite in the Oldham, and glauconite in the

Dayton, indicate that during early Clinton times the land was low and sedimentation slow. The supply of elastics and the rate of basin

subsidence were probably at a minimum. Eventually renewed uplift uncovered the source of iron-rich clay to the east that had produced

the earlier shales of the Cabot Head. The deepening basin received

thick deposits of Estill-Rose Hill shales. At first, sands were

deposited along the eastern margin of the Appalachian basin in West

Virginia, but as flooding increased this strandline moved further

east and the Rose H ill shales were deposited over large areas of

Pennsylvania and Maryland as well as West Virginia. To the northwest,

on the Cincinnftti-Findlay platform, thin carbonates were deposited in

the agitated shallow water. The water level must have fluctuated between critical depths that allowed little permanent deposition.

Toward the end of Estill-Rose H ill times the seas must have receded

somewhat permitting the Keefer delta to build northwestward or

westward. Apparently the southeastern source of shale was nearly

exhausted but an eastern source contributed argillaceous sediment

and deposition of the Rose H ill continued in the Pennsylvania part

of the Appalachian basin. The deposition of the brown argillaceous

Bisher east of the platform represents intermediate water depths between those of the thin pure platform carbonates and the shales of

the Estill-Rose Hill which generally signify slightly reducing

conditions. The Rochester shale of West Virginia was deposited in

a lagoon or restricted embayment centering on the panhandle of

northeastern West Virginia, while farther to the west the bulk of 127 tha argillaceous Bisher was deposited in a wide area bordering the platform. Perhaps currents drifted much of the silt from the

Keefer delta or associated bars along the southern border of the

Cincinnati-Findlay platform. This may have been the source of the silt for the Mississinewa shale of Indiana (Figure 7).

Lockport group. The Peebles and Lilley formations are traced eastward and southward from Highland and northern Adams counties for a distance of at least 1*0 miles in the subsurface. Beyond this lim it the two formations are difficult to separate. The Lilley and Peebles dolomite are essentially equivalent to the Lockport dolomite of eastern Ohio. It is recommended that the name Lockport dolomite be retained for strata overlying the Clinton and underlying the Cayugan in the subsurface of Ohio and northeastern Kentucky. The Lockport dolomite of eastern Ohio intertongues with roughly equivalent lime­

stone of the McKenzie formation in eastern Ohio and western West

Virginia. Most of the Lockport strata in southern and eastern Ohio

is the lithologic equivalent of the middle unit of the Lockport-

Guelph of northern Ohio and southwestern Ontario, although some of

the r e e f a l d olom ites (Bowman, 195>6) o f the L ille y may be sm a ll-s c a le

equivalents to the lower unit.

The Huntington and New Corydon formation names are omitted

from the present classification in western Ohio as a result of misidentification of these rocks in eastern Indiana. The Ohio

outcrops that have been correlated with the Indiana strata need to

be re-evaluated. If both the reclassification of strata in Indiana

(Shaver, 1961) and the correlation of Ohio rock (Busch, 1939) w ith 128 these strata are valid, then Ohio outcrops should be renamed and placed in the Clinton group.

Late Niagaran (Lockport) time was a period of prolific marine life. The cessation of clastic influx, along with warm shallow seas, promoted reef growth, particularly in north-central Indiana. A few small reefs reported in the early literature crop out in northern

Ohio, and recently biostromal buildups and probable bioherms have been found in the subsurface of northern and central Ohio. These reefal dolomites are a southward extension of similar conditions that existed in southwestern Ontario, borne geologists advocate extensive reef bank conditions (Ailing and Briggs, 1961) around the borders of Ohio to produce the restricted basin where Cayugan evaporites were deposited. The marine Lockport sediments of Ohio are apparently continuous with sediments from the McKenzie seas of

West V irg in ia and Maryland, the Guelph-Lockport of O ntario, and the

Liston Creek (including many of the Huntington reefs) of Indiana.

Salina Group. The Greenfield formation of Ohio has wide­ spread and continuous areal distribution. It is considered equivalent to the "A" unit of the balina formation of Michigan and Ontario. The relationship between the Greenfield and probable reef accumulations in northern Ohio must be based on the Green­ field and Lockport isopachs of Ulteig (1963) since most of the reef sites found in Ohio occur in the northern part of the state.

These show the Greenfield thinning over areas of thick Lockport sediments. In some localities the thickened Lockport section represents reef accumulation. The Greenfield is traced into the 129 lower part of the Wills Creek formation as identified in the Sand

H ills well, Wood County, West Virginia.

In Indiana the Kokomo formation (probable equivalent of the

Greenfield) occupies an interreef position. This relationship is considered by some geologists as evidence of reef growth continuing into Cayugan time. Others have pointed out that Kokomo sediments are not necessarily contemporaneous with reef growth.

The Tymochtee shale of Winchell's type section correlates with either the "G", ,,F", or "CM unit, probably the latter, of the

Salina formation as defined by Landes (19U5). Since the upper and lower contacts of the Tymochtee are not visible in the type area, the definition has been expanded for subsurface usage to include all strata below the Salina 11H" unit (Bass Islands equivalent?) and above the Salina "A" unit (Greenfield equivalent) in northern Ohio. Salt, and most of the anhydrite and shale that are the basis for subdividing the Salina formation into units corresponding to Bass Islands,

Tymochtee, and Greenfield in the subsurface of northern Ohio are absent toward the marginal areas of the basin in western and south­ western Ohio. In most of these areas only the 11C" shale unit is present in addition to some nontypical overlying strata. The value of the 11C" shale as a stratigraphic marker (Ulteig, 1963) is en­ hanced by its presence in southern Ohio and parts of West Virginia and Kentucky.

At the time Woodward (19U1) correlated the Tonoloway with the Greenfield, only the Greenfield beds were known to crop out in southwestern Ohio, the Tymochtee outcrops being subsequently 130 discovered by M iller (1955)* Under the circumstances Woodward's error is understandable. Using the "C" shale unit for correlation, • the Tymochtee correlates with the upper part of the W ills Creek and the overlying Tonoloway formation as identified in the Sand Hills w e ll, Wood County, West V irg in ia (Symposium, Woodward, 1957)• The

Tymochtee used in this paper is the broadly defined interpretation of subsurface geologists, or the Salina "A" through "GH units where they are identifiable.

The Bass Islands group has been progressively robbed of its member formations. Originally it was a series name and was composed of the Tymochtee, Greenfield, Raisin River and Rut-in-bay formations.

These formations were named from outcrops that generally represent the basin-margin carbonate facies of the Cayugan evaporite basins.

According to Ailing and Briggs (1961, p. 5l5), these outcrops serve poorly to define the proper framework of Cayugan stratigraphy.

Perhaps the original proponents of the Bass Islands would have used the name Galina if they had known the relationship of the Ohio and

Michigan outcrops to evaporites in the central basin areas. Only in recent years has subsurface information revealed this relationship.

The writer now proposes that the term Bass Islands group, which in recent years has been reduced to a single formation, be eliminated.

The genetic relationship suggested by similar lithology. and fauna in the Greenfield, Tymochtee, and Bass Islands formations support such a proposal.

Landes (19U5), Ailing and Briggs (1961), and Ulteig (1963) accept the Bass Islands dolomite as at least partly equivalent to the 131

"H" unit of the Salina formation of Michigan. The writer has recog­ nized lithology resembling the Bass Islands at various positions within as well as above the Tymochtee formation (broadly defined), and interprets the Bass Islands to be partly a facies of the

Tymochtee formation. The Bass Islands dolomite is not considered correlative with the Keyser formation of West Virginia or Penn­ sylvania, but with the upper part of the Tymochtee in eastern Ohio and with the upper part of the Tonoloway formation in West Virginia.

Part of the configuration and development of the Cayugan evaporite basin is attributed to the development of IJiagaran reef platforms around the Ohio and Michigan basins, as shown by Ailing and Briggs (l?6l, p. !?&). The platforms prevented free inter­ change of oceanic brine. The few scattered wells studied by the writer in Gallia, Scioto, and Lawrence counties do not show any definite buildup of reef bank material. Without detailed investiga­ tion the writer can neither confirm nor deny the location of these reef banks, although the overall picture of reef restriction of the evaporite basin proposed by Ailing and Briggs appears valid. The

Greenfield-Kokomo seas are believed to have been continuous, but whether they joined through the Marietta inlet as suggested by Ailing and Briggs, or through a gap in the Cincinnati platform as suggested by the writer for the earlier Bisher-Tiississinewa seas, is not known. The Greenfield-Kokomo sediments point to conditions of

increasing salinity that resulted in the thick salt and anhydrite deposits of the Subsurface Tymochtee. The persistence of the 11C"

shale unit shows interconnection of the Tymochtee-upper Wills Creek and Tonoloway seas for at least part of Cayugan time. The Bass

Islands seas are believed to have been at least partly contempor­ aneous and continuous with the upper Tymochtee-Tonoloway seas and the resultant sediments may represent shallow or protected environ­ ments where appreciable argillaceous matter was prevented from entering or from being deposited.

Berdan (196U) and others have shown that the lower part of the Keyser (Chonetes jerseyensis zone) is of Silurian age. Since the fauna of the Keyser represents near-normal marine deposition, the writer prefers not to correlate these strata with the hypersaline sediments of the Bass Islands unless reefs or some other semi­ barrier which restricted marine i/aters can be shown to have existed in east-central Ohio permitting normal marine waters alongside hypersaline waters. The Keyser sediments are thought to represent transgressive seas that were contemporaneous with an erosional period in most of Ohio. TABLE 1

WELL LOCATIONS

Bee. or Number County Township Lot Operator Farm

INDIANA I - l h A llen T. 31 II., R. 13 E. 11 Ind. Farm Bureau Baatz 1-2 h A lle n T. 32 I-)., R. 12 E. 33 N. Ind. Fublic Serv. Wakeland 1-3* Grant T. 2h N ., R. 6 £ . 2 Ind., Geol. Survey Sweetster (DH 2$) I-Uf Howard T. 2U N ., R. 3 E. 36 Ind. Geol. survey Kokomo (DH 72) I -5 h Jay T. 23 N ., R. 13 E. 31 Continental Rasur I -6 h Tipton T. 23 N ., R. 3 E. 36 Sun O il 'Wells Estate

KENTUCKY Coordinates K-1S B r e a th itt 13-M-75 United Fuel W illiams K-2h>§ Carter 3-V-77 United Fuel Stamper K-3° E llio t t 2U-T-77 Inland Gas F raley K-U E ll i o t t 21-T-76 United Fuel Pennington k- 5 c Johnson 19-R-79 • Ashland Oil Williams No. 8 k-S c Lewis 18-Y-7U U. E. Lang Clark K-7h Lewis —--- United Fuel Shepherd K-8*1 Martin 19-W-8U United Fuel James

Data from following sources:

a...Driller's log f...Shaver (1961) b...Martens (19h£) g.•.Thomas (I960) c...Freeman (19^1, 19^3) h...Samples, GR-N log or both d...Travis (1962) i...Founder, Imperial Oil (pers. comm.) e ...Mixed sources j...From Geo-Log

\ TaBLE 1—Continued Cample No. County Township Bee. or Operator Farm or dumber Lot Permit

ONTARIO C -C -l1 Essex Colchester So. L-7o Imperial Oil C olch ester (Canada)

)RI0 0- l h Athens Carthage 29 Flagg Co. Chapman S-1089 C-2h Athens Rome 28 Midland Bxplor. Burson P-1395 0-3h Athens • Rome 22 R eal Corp. Skinner S-905 o-l*h Athens Waterloo 16 E l Paso N at. Gas K isor S-1077 o -5 a Adams Eratton — Sinking .Springs Parker D-3 0 - 6h Coshocton Bedford 7 Nat. Assoc. Pet. Gilmore S-761 0-7h Coshocton Keene L-15 Roberson et al. Geib S-69 U 0 - 8 h Crawford Bucyrus 22 Plains Explor. B lick e S-1122 0-9e Delaware Porter L-16 Monk O il & Gas Thurston S-829 O-IOJ Delaware Radnor L-7W J . Adams Humphreys S-1103 o - n h F a ir fie ld Amanda 30 Lancaster N at. Gas Brown S-U38 0 -1 2 5 F a ir fie ld Richland 30 Piubat Ruff 8-91*5 0 -1 3 F a ir f ie ld V io le t 8 Graber F ish er S-8U3 0- 11*5 F a y ette Union l-is-663 Kewanee Hopkins S-750 o-i5h Franklin Columbus(city) Battelle Mem.Inst. B a t t e lle 8-630 o -i6 h G a llia Perry 28 Waggoner G ills 8-915 0-175 Guernsey Adams 15 Lake Shore Pipeline M arshall 8-925 0- 1.35 Hocking Benton 33 Kewanee Amerine S-738 0-19 Hocking Green 3U R ixleben Adcock 8-909 0 -2 0 h Jackson L ib erty 19 Continental Grover S-1023 0-2 l h Jackson i d l t on 23 Kewanee Buckeye S-759 0-229 Knox Jackson 21 Hat. a s s o c . P e t. W ilt S-783 0-23h Lawrence Washington 11 Weed 5c Assoc Cambria Clay 8-900 C-2l*h Licking Hartford L-2 P atten M artin 8-855 0-255 Logan McArthur HS-9930 Ohio O il Johns s-192 0-26 Marion C laridon 3 J . Adams Key 8 - 101*1* H 0-27h Meigs Chester 1-W Ohio F u el Gas Windam S-827 £ Lumber Union to io c S h l 5 - h 0 to -3 cio S to io c S Sandusky -U8** —U7f} -U6, Ross Pike -UUh Pike Pike -U2h Pike lh -U Pike 01 -U Pickaway -39, -38^ Noble -37 -33 Muskingum -32^

36h ’Wayne oooooooooooooooooooooooooooooo h 6 -3 Union 11 3 -3 to cio S -U9“ ichland R -It3^ 37h Wyandot h 'Washington 7 -3 inton V n 3 -3 Union -3U*1 -52h Ross -U3?J 3 ^ Muskingum Muskingum ■3U^ ■33^ Morrow Morrow •3111 Morgan ■30^ ■2 9h 3^ Perry .36^ S Meigs M 2Sh County l n lle A Bennington ille sv ig e M live O Madison Township Beaver Ereercreek Perry Green Union Enoch Highland Troy Townsend l a e S Pebble ngfeld fie g in r p S lley a V esnt leasan P Perry berty ib L erty ib L Concord Tymochtee Swan Huntington Troy Darby ain la P Creek Brush S ec. ec. S TABLE 1—Continued VMS-U016 VHS-I2I4OO VHS-U6U2 Lot VMS-13310 VKS-37U2 VLS-1U887 33 26 L-16 L-23 3-S 20E L-U07 33 9 1 2h 20 L-82 13 3 10 20 23 1 17 18 12 7 o r r o

Maddox cao at . l a t McMahon a Co. Morrow el asel ra B l se a r B rod il O Arnold Adams . J Adams . J Operator Kewanee Kewanee American Pan ir la c in S Adams . J Chem. Dow St Smith Gas Ohio ast E tal en tin on C Gas St il O idgedale R Wahmeyar ra Lks Carbon Lakes Great tal en tin on C Bros g isslin K American Pan riangle T Southern tinental on C Kubat tinental on C tinental on C tal en tin on C ntne tal en tin on C tinental on C ontinental C

is.

Johnston

lkol cik jc lo o ilik YJoodell Anderson r ille M tnger g ttin A Burkhart m a r Dever rie e P ertler M Dunlap Vargo iggs R Murray Jones aff H Wenzel indbigler W Longworth Carreker Rose sell in u Q Lake Eckert Sanger Snyder r isle h S ilkins W ott co S olycross H Hewitt S-895 S-838 8-253 s U 0 -1 S S-10U5 P-22 8-639 S-1033 S-1091 Permit ape No. Sample s S-1068 S-U37 S-1067 S-1072 S-153 S-1095 S-1121 8-1070 P-21 S-1178 S-921 S-779 0 1 s-2 S-1071 S-633 S- S-1066 S-787 S-91U -1009 -1010 6 U or 0 vj

\ TABLE 1- -Continued 4 Sample : Iv umber County Township S ec. or Operator Farm Lot Permit

U.VIRGINIA W-lQi h F ayette liu t t a ll S h e ll O il Foulke 123 V/-2b >6 j h Harrison Grant — Hope H at, Gas G ribble 79 w-3e ,h Greenbrier White oulphur — United Fuel Damron 13 V/-Ue»h G reenbrier YJilliamsburg — Texas Co. Dean 2 Hardy K o o refield — Baker

ecr\ Ta b L a 2 \ NELL DATA

Guelph- L iston K is s is s - Lower Cabot Number E lev. Kokomo Lockport Creek inewa iiiagaran Head B r a s s fie ld Ordovician

INDIANA 1 -1 807 326 512? — 61*6? 800? 9U0? 1-2 856 310 335 550? — 710? 785? 880? 1-3 8ll* —— 11 59 169 299 309 1-1* 80l* 7 — 51 125 21*0 362 392 1-5 922 — .100 — — — 190 210 260 1-6 880 110 130 '205 300 1*10 1*80

Tymoch­ Green­ Naco— Plum B ra ss- Number 2 le v . te e field Lockport B isher Big 6 E s t i l l Ordovician

KY. K -l _ _ _ _ —-- — 2103 2165 21*80 2520 K-2 8U6 1265 1335 1360 1390 11*1*5 ll*53 1637 1652 1661* 1665 1728 K-3 796 11*1*3 — 1613-2. — 1713 1762 1922 1950 2082 K-U 918 — — — 11*1*0 U*55 1510 161*0 1670 1700 1712 1835 K-5 1563 1770 1865 1955 1989 2028 2265 22902*23002. 23102. 2360 K-6 —- — 270 300 — 31*5 1*80 1*95 500 515 555 K-7 910 ----- — 825 915 — 975 111*5 11522.1162 1192 1235 K-8 3080 3305 3U30E. 31*63 3502 3520 C l. Sd. '>095 61*7 3888 ^ °

Tymoch­ Green­ Cabot Clinton Brass- Number £ le v . te e f i e l d Lockport Bisher Estill Dayton

ONTARIO O -C -l 606 750 895 -- 1268 - dSlt.)^10 2 . . estimated formation top T. elevation from topographic map TABLE 2—Continued

Tymoch­ Green­ Cabot Clinton Erass- Number E lev. te e field Lockport B isher E s t i l l Dayton Oldham Head bands field O rdovician t OBIC 0-1 712 3670 U230E. U260E. 3396 l*l*5o 1*626 1*61*0 1*61*6 1*761* 1*735? 1*8607 0-2 827 MM 1*296 WM U5oo 1*666 1*682 1*686 1*732 — 1*910 0-3 653 3550 MM 1*275 1*335 l*5ol* 1*518 1*522 1*735 1*753 o-l* 958 2773E. 3250 -- 3U50 3510 3660 — 3670 37U8 — 3815 0-5 800 MM 85' 180 190 395 — — ~ l*oo? 1*75 0-6 1096 2U96 2918 3111; . 3226 3338 3376 3389? 3U12 31* 32 31*82. 3500? MM 0-7 807 3270 3335b. 35U5 3656 3685 3720? 3750? 3794 ~ C-8 993 385 510E. 785b. — ~ — — 910 — 965 iol*o 0-9 1177 mm MM — ------1585? 1610? I61i0? —— 1670? 0-10 920 MM MM — -M — 1*70? — 1* 80 ? 520? ? 580 0-11 835 1005 1230 1275 1330 1392 1U05 MM U*60 1517 — 0-12 mm 1660 1950E. 2000E. 2270 2350 21*20 21*35 2U5o- 2U55 2U85 0-13 71*2 950 1170? 1215 — 1307 1315? 131*5 — 1375 il;55 C-ll* 965 60? 115? — 220 21*6 285 —— — 300 355 o -i5 7l*5 200? 365 585 61*0 680 690 — — — 700 823 o -i6 633 2555 2950 3000 3110 31U3 3310 3330? 331*0? 3390 3375 — . 0-17 995 3580 1*01*0 l*i5o 1*310? MM 1*535 1*560 1*575 U635 — 1*71*0? 0-18 1061S. MM __— ------21*92 2533? — 2572 2550 — .M __— — 0-19 81*». --- 2767? 2773? — 2860 — C-20 959 i5oo? 1685 1725 18U0 1900 2052 2075 2067 — 2137 2210 0-21 765 2090 2U5o 251*0? 2625 2670 2830 2870 2890 2895 291*5 3025E. MM — — 0-22 880 MM 2810 2896 2930 2950 — C-23 2170 2530 2615E. 2660 2705 2865 2685 291*0? 2915 — 0-21; 1185T. 12U5 151*5 1760 1815 — 1890 1900 1925 — 1965 2035 0-25 1186 70 MM 330 U35 l*5o 1*60 ——— 1*65 500 9 0-2 6 996 MM —— 915 925? • — 970B. 1050 0-27 723 3600 3955? U150? 1*330 -- 1*535 — U55o 1*685- 1*615 1*785 MM 0-28 819 1*21*0 1*813 1*963 5070 5085 5313 5335? MM 5381* • 5535 £ ____ CD 0-29 865 39UO U560? U670E. 1*750 U820 1*970 “ 5068 5036? TABLE 2—Continued

Tymoch­ Green­ Cabot Clinton Brass- Number E lev. tee f ie ld Lockport Bisher E s t i l l Dayton Oldham Head Sands f i e l d Ordovician 0-30 1227 101*5 1375 1613 1650 1720 1730? 171*5 1785 1850 0-31 1398 1230 U+50 1520 1955 1980 ? 2000 — 2070 2130 0-32 1012 31*30* 391*0 1*055? 1*210? 1*255 1*360 1*385 1*393 1*1*35 — U560 0-33 91*9 3230 3760 3990 1*050 1*110 1*212 1*235 — 1*300 1*250 1*1+20 0-3l* 788 2380 2835 3050E. 3160 3200 3290? 3312 — 3378s, 3360£o 31*68 0-35 1160 5092 5818 60l*0E. 6070 611*5 6298 6325? 61*12 6370? 3?9Q & 0-36 970T. 2635 3115 3186 3381* 31*23 351*0 3570? ---- 3610 3655 — 0-37 719 157 21*0 280? 1*1*5 5oo 565 580 590 615 685 . 0-38 661 .995? 1158 1201 1330 1358 1508 1530 151*2 — 1586 0-39 681 1+52 580 625 728 791 926 91*0 91*6 — 986 1030 0-1*0 939 — 135 156 29U 362 1*66 1*72 1*76 — 500 530E. 0-1+1 696 812? 968 1013 1120 1180 1325 13U2 135U — 1391* m soE . 0-1*2 800T. 1032 U60 1215 1275 1355 1500 1510 1520 15U5 0-1*3 1270 1390? 1680 1750 2015? 2070 — 2105 — js*i 221*0 o-UU 135? 275 31*9 1*79 550 615 — — — 625? 710 o-l*5 91*9 668 732 782 1011* 1038 — — ——— 0-1*6 61*1 150 1*20 615 — — ... 765 — 800 885 0-1*7 588 157 221* 268 376 1*00 ——— —— 0-1*8 1690 1900 1930 2002 2052 2222 2275 2285 — 2330 2390 0-1*9 585 1350? 151*0 1580 1676 1722 1885 1918 191*0 — 1977 2038 o-5o 525 710? 861*? 901*? 1012 1050 — — — — — o-5i 10i*0 ? 195 280E. — 380 — — — 1*25? 1*90? 0-52 __— 285E. 360 — — 1*70 1*80? 1*8? — 512 570. o-53 1076 1*0 170E. 255 — __ 365 ..— 390 1*60 o-5l* 971 1930? 2260 2325 21*50? 2535 2665 — — 2702 2695? 2755 o-55 901* 51*10 6185 6375 61*25 65ol* 6709 671*5? 6751*? 6827 6781* 0-56 1072 2260 2765 2885E. 301*5 3113 3132 — —— 3157 3225B. TABLE 2— Continued

Lockp.- Number Elev. Tonoloway W ills Ck. McKenzie Rochester Keefer Rose H ill Cacapon Tuscarora Juniata

W. VA. W-l 2150 7250E. ... 7840 8070 8090 8285 8440 — W-2 1113 7785 — 8730 9170 ■9200 9210 9630 9745 9995? W-3 2841 5465 ---- 5345 — 6387 6490 6675 6825 7020 V<—4 2575 7110E. ---- 7550 • — 7705 7725 7935 7990 — w-5 1377 — — 2545E. 2310 2830 2855 3235 3360 3800 w-6 740 4975 —— 5477 ---- 5697 5723 6115 6130 6251 v/-7 984 5025 ---- 5600 ---- 5775 5800 6095 6215 6320 W-8 597 3520 3870 ? 4025 4145 4170 — 4475 4580 V/-9 3780 7040 —— 7840 ---- 8035 8045 8305 8516E. 8690 VJ-10 2239 5170 . 5590S. 6195E. 6515 6575 6600 7100 7300 7813 W -ll ' 2920 5550S. — — 6550E. 6665 6740 6750 4 7040 7300 7800 W-l 2 1050 6150 665OE. 7015E. — 7215 7250 — 7685 7813 APPFHDDL A

Log of core from Continental- Attinger well, state permit Ho. 21, Perry Township, Pike County, Ohio. Alevation 930 feet.

Devonian system, 71 ft. of rock cored: Depth Ohio and Glentangy Chale, 71 ft.; (ft.)

1. Shale, dark brown, compact finely pyrit- ic, and shale, greenish-gray, somewhat softer; thin beds (i; to 6 inches) of shaly dolomite occur between 92 and 9k f e e t . ------6U.0 to 133.0

Silurian System, 399 ft. of rock cored: Greenfield Formation, 21 ft.:

1. Dolomite, mostly dark brown, fine-grained w ith many sm all v e s ic le s or vugs; \ in ch pyrite and limonitic weathered zone at upper co n ta ct; co lo r changes to medium and pale brown in lower 2 ft. which is less porous; Leperditia at 137 f t . ------1 3 3 .0 to 1U0.0

2 . D olom ite, medium to dark brown, f in e - to medium- grained, porous, and suerosic; oolites at 1U2 ft.; moderately porous with small vesicles at intervals ------ll|0 .0 to

3. Dolomite, pale brown to brownish-gray, fine- to very fine-grained, irregularly bedded; porosity is variable, but mostly low w ith sc a tte r e d v e s ic le s ; some fr a c ­ tures in lower 5 f t . ------1UU.6 to 13U.3

•Peebles Formation, 107 ft.:

1. Dolomite, pale brown, fine-grained, partly fractured and vesicular; some cavities with asphaltic material; a \ to 1 in ch weathered clay zone at top — ------13U.Q to 168.0

D ll 1U2

Depth (ft.) 2. Dolomite, gray and brownish-gray mottled, fine-grained, massive, moderately vesic­ ular; gastropods at 170 and 180 ft. -—— 168.0 to 208.0

3. Dolomite, buff to pale brown, fine-grained and partly dense; vesicles from 217 to 218 ft. and a few from 22$ to 232 ft.; some gastrop od s; many c o lo n ia l c o r a ls from 2Ul to 2$0 ft.; Fletchereria sp. at 2U6 f t . 2 0 8 .0 to 2 5 8 .0

1*. Dolomite, gray to brownish-gray with pale brown limy swirls and patches at 260, 261 and 262 ft.; colonial corals 250.0 to 262.5

Lilley formation, 31.5 ft.;

1. Dolomite, mostly gray, fine-grain3d, dense, carbonaceous; contains pale brown dolomite or limestones swirls of corals; white calcite along stylolites and frac­ tures at 26U ft.; lower U ft. is partly medium-grained and contains crinoids, brachiopods, and corals (Coenites sp.) — 262.5 to 276.0

2. Dolomite, gray and brownish-gray, mostly fine-grained, irregularly bedded, moder­ ately argillaceous and silty; milky chert at 280 ft, and milky chalcedonic chert at 231 and 286 ft.; some colonial corals (Coenites sp. and r*avosites sp.) at 286 ft. and 292 ft. ------276.0 to 2?U.O

Eisner formation, 68.0 f t .:

1. Dolomite, pale brownish-gray to gray, fine-grained, thin-bedded, moderately silty and argillaceous; a 1 inch brecci- ated chert layer at 2 9 k f t . ; some p o ik i- loblastic texture at 2 99 ft. and a very silty zone at 301 ft.; some high angle bedding at 309.5 ft. ------29U.0 to 311.0

2. Dolomite, calcareous, grayish-brown, mostly fine-grained; gray to white chert at 315, 317, 323.5, 330.5 and 333.7 ft.; poikiloblastic texture at 317 and 326-330 ft,; crinoids at 317 and 325 ft.; ostra- cods at 330.5 and 333.7 f t . — ------311.0 to 33U.O 11*3 Depth (ft.) 3. Limestone and dolomite, pale brown to brownish-gray, Line-grained; the upper 1.5 ft. is the limestone ------334.0 to 338.0

1+. Dolomite, pale brown to brownish-gray, argillaceous and calcareous, mostly fine­ grained: a 6 inch gray shale at 351.2 and a 3 inch shale at 352 ft.; a 6 inch bed of medium to coarse grained limestone at 355.0 ft.; crinoids at 353.0 and brachio- pods at 355.0 ft. ------338.0 to 355.5

5. Dolomite, calcarous, pale brown, fine- and medium-grained, slightly argillaceous and silty from 357.5 to 362.0 ft.; argillaceous from 362.0 to 362,5 ft.; many crinoids at 356 f t . and some a t 357.5 f t . ------355.0 to 362.0

S still formation, 103.8 ft.:

1. onale, greenish-gray and dark red-brown, interbedded with thin (;v to \ inch) beds of limestone from 373 to 39k ft.; at 1+08 f t . ; from 1+37 to 1+1+7 f t . ; and Uli.7 to 1+60 ft.; a few brachiopods at 1+1+2 ft, ------3 6 2 .0 to 1+65.8

Dayton Formation, 7.0 ft.:

1. Limestone, partly shaly, green to pale brown to pinkish-brown, fine- to medium- grained — 1+65.6 to 1+72.8

2. Limestone, tan with yellow and green tint, medium-grained with 1+thin shale inter­ beds; slightly glauconitic at top; c r i n o i d a l ------. 1+72 .0 to 1+71+.0

Oldham Form ation, 2 .0 f t . :

1. Hematite, calcareous, oolitic, fossil- iferous, 1+71+.0 to 1+75.0

2. Limestone, dark red-brown, fine- and medium-grained ------1------1+75.0 to 1+76.0 ■ m

Depth (ft.) Cabot Head formation, 2U.0 ft.:

1. bhale, greenish-gray; h inch bed of limestone at U76.3 ft. and a 3 inch raddisn-brown and yellow snaly lime­ stone bed containing some crinoids, bryosoans and brachiopods at U82 ft. ------U7o.O to U88.0

2. Limestone, greenish-gray to reddish- brown, medium-drained, slightly hematitic and lim onitic ------1;88.0 to 1|90.0

3 . Shale, greenish-gray with a 3 and a k inch very fine-grained limestone bed at U96.2 and I4.97.I ft. which resemble Dayton lithology ------1*90.0 to 500.0

Brassfield i’'ormation, 3U.0 ft.?:

1. Hematite, calcareous, oolitic 500.0 to 502.0

2. Limestone, brownish-gray to pinkish-gray to greenish-gray, fine- and medium-grained;

coarse-grained from 503.5 to 505.5 ------502.0 to 505. VI

3 . Shale, greenish-gray, lim y 505.5 to 506.7

1*. Hematite, calcareous, oolitic 506.7 to 507.5

5. Limestone, shaly, pale browhish-gray to greenish gray with thin greenish-gray shale interbeds; the lower 2.7 ft. is dominantly shale 507.5 to 518.7

6. Limestone, mostly pale grayish-brown, medium-and coarse-grained with some very thin irregular streaks of green shale 513.7 to 529.7

7. bnale, calcareous, greenish-gray; contains small limestone fragments and irregular lenses of brownish-gray medium-grained limestone; (basal Brassfield or uppermost Richmond?) 529.7 to 531*. 0 AEPE a DIX E

Log of -core from Continental-iiiller well, state permit No. 22, Pebble Township, Pike County, Ohio. Elevation 681 feet.

Devonian bysteid, UU0.2 ft. of rock cored: Depth Ohio and Glentangy bhale, UU0.2 ft.; (ft.)

1, bhale, dark gray to gray-brown to \ greenish-gray; partly soft; partly iiard and fissile; concentration of pyrite crystals 190-190 ft.; shale is locally calcareous or dolomitic; core missing UU0-UU8 f t . 1 0 .0 to UbO.2

Silurian System, 379.8 £t. of rock cored: Tymochtee formation5, 130.2 ft.:

1. Dolomite, pale brown to brown, fine­ grained, with small vugs or vesicles contains pyrite or asphaltic residue; upper b in. is very fine-grained with \ inch p y r ite seam and lig h t gray cnerty oolitic layer at top; porosity varies

from 5 to 35/» lo ca lly ------4p0.2 to u5U. v n

2. Dolomite, pale brown to brown, fine­ grained, with thin carbonaceous laminae and scattered asphaltic vesicles; porous and with scattered pyrite crystals to U63.U

3. Dolomite, pale brown to brownish-gray, fine-grained, moderately dense; partly mottled light and dark brown; small vesicles at U77.5 ft.; numerous thin carbonaceous laminae; l/l6 inch pyrite seam at U8U.0 ft.; ostracod at U65.0 ft. 2i63.1; to k92 .0

^Strata from h$0.2 to about 523.9 is nontypical Tymochtee that partly resembles the 11ais in liver dolomite, bee text.

11*5 iii6

Depth ( f t .y U. Dolomite, mostly pale brown, fine-grained with small vesicles at 592.5 and 503.2 ft.] a dolomite conglomerate at 592.0 it.; calcareous dolomite from 500 to 505 ft,; oolitic dolomite at 592.0, 511.0 and 513.7 ft. (some siliceous oolites at latter depth); \ inch bed of greenish- gray shale at 525.0 ft.; brachiopods at 531.0 f t ...... 592.0 to 533.0

5. bhale, gray with green mottling;; contains thin irregular dolomite laminae (part of the 11 l" and 11C" or 11C” shale of the oalina fm.). ------533.0 to 536.7

6. Dolomite, pale brown to brown with some green tinges; contains many thin nray shale laminae and partings; lower 5.5 ft. consists mostly of fine-grained greenish- gray dolomite; ostracod at 557.6 f t . 536.7 to poO.O

G reen field form ation, 154.5 f t . :

1. Dolomite, brown to grayish-brown, fine­ grained, locally porous; vesicles or small vugs at 565.0, 603.0 and. 60U.0 ft,; thin irregular carbonaceous laminae; ostracods . at 565.0 and 603.0 to 60U.0 ft.; pale brown mottling at 606.0 ft. ------560.0 to 60y,5

2. Dolomite, pale brown to grayish-brown, fine-drained, sligntly porous to dense; ostracods at 610.5 and 623.0 f t . 609.5 to 62)4,5

feebles formation, 75.5 ft.:

1. Dolomite, pale brown to brownish-gray, partly mottled; scattered vesicles; a fractu red and weathered dolom ite and a thin light gfay clay from 625.5 to about 62 5.5 ft.; some gastropods from 633.0 to o3o.0; colonial corals 625.5 to 653.6

2. Dolomite, pale brown to gray to dark gray­ ish-brown, fine-drained, mostly danse with a few scattered vesicles; several th in sh alo p a rtin g s con tain in g some rounded dolomite fragments in lower foot; colonial corals (mostly 5avosltes). ------653.0 to 651.5 UU7

Depth («.) 3. Dolomite, pale brown to brownish-gray, fine-grained, very porous and vugular from 6 5 6 .0 to 6 5 7 .0 ft.; pale brown color swirling and porosity at 6 5 6 .0 i s from colonial animal remains; colonial corals ani, scattered 'rug 3; a few bracaiopods in

U. Dolomite, dark gray to brown x.o brownish- gray, fine-trained, with irregular pale brown streaks anu swirls; scattered ves­ icles becoming more numerous from 697.5 696.5 ft.; colonial corals ------690.0 to 700.0

Lilley formation, 26.0 ft.;

1. Dolomite, dark ^ray oo brownish-gray, fine- to medium-drained, dense with close- spaced carbonaceous laminae in places; lower 6 inches consists of snaly argill­ aceous dolomite ------700.0 to 710.0

2. Dolomite, „ray with pale brown mottlin^, fine- to coarse-grained; irregular carbon­ aceous laminae; pyrite at 715 ft.; slightly fractured rock at 73-6 and 722 ft.; porosity at 72U to 725 ft.; crinoidal; slightly argillaceous ------710.0 to 72o.O iis her format ion, 62.3 f t .;

1. Dolomite, mottled gray and pale brown, fine- and medium-grained; slightly porous

locally;✓ some fracturing . W and carbonaceous s tre a k s ; 7U0 to 7U6 f t . in te r v a l shows poikiloblastic texture; crinoids ------726.0 to 75h .o

2. Dolomite, pale brown, fine- and medium- grained; partly porous; gastropods at 755.5 to 756.5 ft.; brachiopods 759.0 to 762.6 ft.; crinoid columnals 75U.6 to 773.0

3. Dolomite, light brownish-gray, fine­ grained, dense with irregular dark gray to greenish gray thin shale laminae; residua from dolomite contains quartz s i l t 773.0 to 790.6 U i6

Depth (ft.) B still formation, 135.2 ft.:

1. Shale, gray to greenish-gray to brown or reddish-brown; a 5 inch bed and a 1 in ch bed of dolomite at 805.0 and 808.2 f t . respectively 790.8 to 926.0

Dayton formation, 8.0 ft.:

1». Dolomite, lig.it gray to greenish-gray to brown, fine- and medium-grained; thin- bedded; snaly in top 3 inches with glauconite in this uppermost shale and dolomite. 926.0 to 931.0

Lulbegrud x ormation, 6.0 i't.:

1. Snale, ^reen and brown 931.0 to 910.0

Oldham formation, 7.0 ft.;

1. hematite, oolitic, becoming more calcar- . eous and fossiliferous at 9l l ft., o s tr a ­ cods and gastropods ------910.0 to 912.0

2. Dolomite, brownish-gray, medium-grained and snale, green; interbedded units range betw een 3 and 10 inches; lithology at 912 ft. identical to Oldham sample from type- sec t i o n ------?12.0 to 941.0

3. Hematite, ooliuic, calcareous, and fossiliferous 9al.5 uo 916.1’

Cabot Head formation, 39.9 ft.:

1. bhale, mostly greenish-gray; a 1.1 f t . pale brown, coarse-grained bed of limestone at 980,3 ft.; s e v e ra l 1 to 2 inch dolomite beds occur between 918 and 9&1 f t . ------916.1 to 936.0

Brassfield formation, 11.2 ft.;

1. Limestone, light brownish-gray, medium- grained and shale, greenish-gray 986.0 to 988.9 Xk9

D e p th ( f t . ) 2. Hematite, oolitic, calcareous; a couple inches of irregular'interbedded lime­ stone (brown) in the lower 6 inches 955.9 to 990,14

3. Limestone, brownisn-gray, medium-grained, interbedded with snale greenish-gray; some th in dolom ite beds and some orange dolomite crystals at 99U.S f t . ------990.14 to 1000.1;

U, Dolomite, brownish-^ray, medium-grained, slightly glauconitic and argillaceous; intervals of brownish-gray ch ert 1000,14 to 1005.3

5. Limestone, brownish-gray, fine- to coarse­ grained; trace of chert; a I4 inch bed of greenish-gray snale at 1010.1 ft. ------1005.3 to 101U.5

0. bhale, greenish-gray with thin inter­ bedded limestone, brownish-gray, medium-grained ------10114.3 to 1023.0

7. Limestone, snaly, brown and green, fine- and medium-grained with interbeds of thin calcareous, greenish-gray shale ------1023.0 lo 1030.2

Ordovician bysten, 55.6 ft. of rock cored: Richmond Group, 55.6 ft.:

1 . ohale, greenish-gray and dark red-brown interbedded with green to brownish- gray fine-grained limestone ’1030.2 to 1059.0 REFERENCES CITED

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, 190ljb, The Silurian of northern Indiana, in Hopkins, T.C., A short description of the topography of Indiana, and of the rocks of the different geological periods: Indiana Dept. G eol. and Nat. Resources, Ann. Rept. 28, p. 33-39#

y 1906, The Silurian, Devonian and Irvine formations of east- central Kentucky: Ky. Geol. Survey, Bull. 7, p. 369#

, 1917, Notes on Silurian fossils from Ohio and other states: Ohio Jour. Sci., v. 17, p. l8?-20lw

} 1919, Silurian fossils from Ohio with notes on related species from other horizons: Ohio Jour. Sci., v. 19, p . 367-UOU.

f 1923, Notes on Hedinan, Niagaran, and Chester fossils: Denison Univ. Sci. Lab. Bull., v. 20, p. 37-120, pis. U-l5a.

f 1929, The correlation of the oilurian with that of the Springfield area (abs.): Ohio Jour. Sci., v. 29, p. 168-169#

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, 1935, Correlation of Silurian formations in southwestern Ohio, southeastern Indiana, Kentucky, and western Tennessee: Denison Univ. bull., v. 30, P# 119-205.

Folk, R. L.j 1962, retrograpny of a oilurian section in Vj.Va.: Jour. Sed. Petrography, v. 32, no. 3, p. 539, 578.

Freeman, Louise 3., 1951, Regional aspects of Silurian and Devonian stratigraphy in Kentucky: Kentucky Geol. Burv., Ser. 9, Bull. 6, 565 p., 23 figs.

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} and others, 1957, a symposium on the Sand H ills deep well: West V irg in ia G eol. ourvey R ept. o f I n v e st. Ho. 18, 182 p.

Yeakel, L. s., Jr., 1962, Tuscarora, Juniata and Bald Eagle paleo-currents and paleogeography in the central Appalachians; G e o l. 0 0 c. America L ull., v. 73, P. 1515-15UO. WOOD CQ OMCNC CO. UNION c a MUSKINGUM CO. taomr.n*. 44 M L If • o u t c r o p s e c t io n AOAMS KEWANEE

§

r7

CROSS SECTION A-B SILURIAN STRATA FROM GREENE COUNTY, OHIO TO ALLEGANY COUNTY, MARYLAND HARDY C a AtLEOANV CD HOK BAKER4M 9HBERQER OUTCROF SECTION

ss

$x CROSS SECTION A-B SILURIAN STRATA FROM GREENE COUNTY, OHIO TO ALLEGANY COUNTY, MARYLAND

1964

LITHCLOGIC SYMBOLS

[ / Q yjvuQULAR DOLOMITE |. . y . . | 'NON-STAINED SAHOSTO

|j j \ DOLOMITE | j-tTj [ POLOMITIC LIMESTONE

(III LIMESTONE | + | OOUTlt HIHMlIl

| [•»•] | SANDY LIMESTONE j^^ANHYDRtri

| SANOSTONI SILTSTONE

[-.-J. -| *U»OUAHT*IT* | /•-—| !ILTVdolomite

I -*• — [oOLOMITie SHALE OR SNA T DOLOMITE | — — | SHALE

j | SLADCONITE j | ANHYPRITlC DOLOMITE

| ^ & | CHUT

| = n | mURM&OIB MALE M LIMESTONE j

------Daihid linos Iromh«II i wsll indicats di«islons olhtr TONQLOWAV

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rr CROSS SECTION C-D N__ SILURIAN STRATA FROM HIGHLAND COUNTY. OHIO TO ALLEGHANY COUNTY. VIRGINIA

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