GEOLOGICAL SURVEY PROFESSIONAL PAPER 111()-A-L 
ON THE COVER 

Swamp-forest landscape at time of coal formation : lepidodendrons (left) , sigillarias (in the center), calamites, and cordaites (right), in addition 

to tree ferns and other ferns. Near the base of the 

largest Lepidodendron (left) is a large dragonfly 

(70-cm wingspread). (Reproduced from frontispiece in Kukuk, Paul (1938), "Geologie des Niederrheinisch-W estfaJi.schen Steinkohlengebietes" by permission of Springer-Verlag, New York, Inc.) 
The Mississippian and Pennsylvanian 

(Carboniferous) Systems in the United StatesA. Massachusetts, Rhode Island, and Maine, by James W. Skehan, S.J., Daniel P. Murray, J. Christopher Hepburn, Marland P. Billings, Paul C. Lyons, and Robert G. Doyle 

B. Pennsylvania and New York, by William E. Edmunds, Thomas M. Berg, William D. Sevon, Robert 

C. Piotrowski, Louis Heyman, and Lawrence V. Rickard 

C. Virginia, by Kenneth J. Englund 

D. West Virginia and Maryland, by Thomas Arkle, Jr., Dennis R. Beissell, Richard E. Larese, Edward 

B. Nuhfer, Douglas G: Patchen, Richard A. Smosna, William H. Gillespie, Richard Lund, 

Warren Nor ton, and Herman W. Pfefferkorn 

E. Ohio, by Horace R. Collins 

F. Kentucky, by Charles L. Rice, Edward G. Sable, Garland R. Dever, Jr., and Thomas M. Kehn 

G. Tennessee, by Robert C. Milici, Garrett Briggs, Larry M. Knox, Preston D. Sitterly, and Anthony 

T. Statler 

H. Georgia, by William A. Thomas and Howard R. Cramer 

I. Alabama and Mississippi 

Mississippian stratigraphy of Alabama, by William A. Thomas 

Pennsylvanian stratigraphy of Alabama, by Everett Smith 

Carboniferous outcrops of Mississippi, by Alvin R. Bicker, Jr. 

J. Michigan, by Gar land D. Ells 

K. Indiana, by Henry H. Gray 

L. Illinois, by Elwood Atherton and James E. Palmer 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1110-A-L 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1979 
UNITED STATES DEPARTMENT OF THE INTERIOR 

CECll. D. ANDRUS, Secretary 

GEOLOGICAL SURVEY 

H. William Menard, Director 

Library of Congress catalog-card No. 79-52491 

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 

Stock Number 024-001-03174-4 
FOREWORD 

The year 1979 is not only the Centennial of the U.S. Geological Surveyit is also the year for the quadrennial meeting of the International Congress on Carboniferous Stratigraphy and Geology, which meets in the 

United States for its ninth session. This session is the first time that the 

major international congress, first organized in 1927, has met outside 

Europe. For this reason it is particularly appropriate that the Carboniferous Congress closely consider the Mississippian and Pennsylvanian Systems; American usage of these terms does not conform with the more 

traditional European usage of the term "Carboniferous." 

In the spring of 1976, shortly after accepting the invitation to meet in 

the United States, the Permanent Committee for the Congress requested 

that a summary of American Carboniferous geology be prepared. The Geological Survey had already prepared Professional Paper 853, "Pale<>tectonic Investigations of the Pennsylvanian System in the United States," 

and was preparing Professional Paper 1010, "Paleotectonic Investigations of the Mississippian System in the United States." These major 

works emphasize geologic structures and draw heavily on subsurface data. 

The Permanent Committee also hoped for a report that would emphasize 

surface outcrops and provide more information on historical development, 

economic products, and other matters not considered in detail in Professional Papers 853 and 1010. 

Because the U.S. Geological Survey did not possess all the information 

necessary to prepare such a work, the Chief Geologist turned to the Association of American State Geologists. An enthusiastic agreement was 

reached that those States in which Mississippian or· Pennsylvanian rocks 

are exposed would provide the requested summaries; each State Geologist 

would be responsible for the preparation of the chapter on his State. In 

some States, the State Geologist himself became the sole author or wrote 

in conjunction with his colleagues ; in others, the work was done by those 

in academic or commercial fields. A few State Geologists invited individuals within the U.S. Geological Survey to prepare the summaries for their 

States. 

Although the authors followed guidelines closely, a diversity in outlook 

and approach may be found among these papers, for each has its own 

unique geographic view. In general, the papers conform to U.S. Geological 

Survey format. Most geologists have given measurements in metric units, 

following current practice; several authors, however, have used both 

metric and inch-pound measurements in indicating thickness of strata, 

isopach intervals, and similar data. 

III 
IV FOREWORD 

This series of contributions differs from typical U.S. Geological Survey stratigraphic studies in that these manuscripts have not been examined 

by the Geologic Names Committee of the Survey. This committee is 

charged with insuring consistent usage of formational and other stratigraphic names in U.S. Geological Survey publications. Because the names 

in these papers on the Carboniferous are those used by the State agencies, 

it would have been inappropriate for the Geologic Names Committee to 

take any action. 

The Geological Survey has had a long tradition of warm cooperation 

with the State geological agencies. Cooperative projects are well known 

and mutually appreciated. The Carboniferous Congress has p·rovided yet 

another opportunity for State and Federal scientific cooperation. This 

series of reports has incorporated much new geologic information and for 

many years will aid man's wise utilization of the resources of the Earth. 

H. William Menard 

Director, U.S. Geological Survey 
CONTENTS 

A. Mass·ach usetts, Rhode Island, and Maine, by James W. Skehan, 

S.J., Daniel P. Murray, J. Christopher Hepburn, Marland 

Page 

P. Billings, Paul C. Lyons, and Robert G. Doyle --------- Al 

B. Pennsylvania and New York, by William E. Edmunds, Thomas 

M. Berg, William D. Sevon, Robert C. Piotrowski, Louis 

Heyman, and Lawrence V. Rickard ------------------- Bl 

C. Virginia, by Kenneth J. Englund ------------------------- Cl 

D. West Virginia and Maryland, by Thomas Arkle, Jr., Dennis R. 

Beissell, Richard E. Larese, Edward B. Nuhfer, Douglas 

G. Patchen, Richard A. Smosna, William H. Gille~pie, Richard Lu~d, Warren Norton, and Herman W. Pfefferkorn _ Dl 

E. Ohio, by Horace R. Collins ------------------------------- El 

F. Kentucky, by Charles L. Rice, Edward G. Sable, Garland R. 

Dever, Jr., and Thomas M. Kehn ---------------------- Fl 

G. Tennessee, by Robert C. Milici, Garrett Briggs, Larry M. Knox, 

Preston D. Sitterly, and Anthony T. Statler ------------ Gl 

H. Georgia, by William A. Thomas and Howard R. Cramer----- Hl 

I. Alabama and Mis,si~ssippi 

Mississippian stratigraphy of Alabama, by William A. 

Thomas ------------------------------------------- Il 

Pennsylvanian stratigraphy of Alabama, by Everett Smith 

Carbo~iferous outcrops of Mississippi, by Alvin R. Bicker, 

Jr ------------------------------------------------ J. Michigan, by Garland D. Ells ----------------------------- Jl 

K. Indiana, by Henry H. Gray ------------------------------- Kl 

L. Illinois, by Elwood Atherton and James E. Palmer----------- Ll 

v 
The Mississippian and Pennsylvania.n 

(Carboniferous) Systems in the United 

States.-Massachusetts, Rhode Island, and 

Maine 

By JAMES W. SKEHAN, S.J., DANIEL P. MURRAY, 

J. CHRISTOPHER HEPBURN, MARLAND P. BILLINGS, 

PAUL C. LYONS, and ROBERT G. DOYLE 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1110-A 

Prepared in cooperation with the Massachusetts Department 

of Public Works, the Massachusetts Department of 

Environmental Quality Engineering} Office of the State 

Geologist) and the Maine Geological Survey) 

Department of Conservation 

Historical review and summary of areal, stratigraphic, 

structural) and economic geology of Mississippian and 

Pennsylvanian rocks in Massachusetts) Rhode Island) 

and Maine 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1979 

CONTENTS 

Abstract 

Introduction -----------------------------------------------------------------

).lcknovvledgments -------------------------------------------------------- Narragansett Basin of Massachusetts and Rhode Island, by James W. Skehan, 

S.J., and Daniel P. Murray --------------------------------------------

Basin configuration ------------------------------------------------------

Stratigraphic relationships ---------------"'"-------------------------------

Coal deposits ------------------------------------------------------------ Structural geology -------------------------------------------------------

Metamorphism ----------------------------------------------------------- Igneous activity ---------------------------------------------------------

).lge relationships -------------------------------------------------------- Norfolk Basin of Massachusetts, by Daniel P. Murray and James W. Skehan, S.J. 

Woonsocket and North Scituate Basins of Massachusetts and Rhode Island, 

by James W. Skehan, S.J., and Daniel P. Murray ----------------------------

Deposits near Worcester, Mass., by J. Christopher Hepburn ------------------

Boston Basin, Massachusetts, by Marland P. Billings ------------------------

Lithology ---------------------------------------------------------------- ''Basement" ----------------------------------------------------------

Mattapan and Lynn Volcanic Complexes ------------------------------

Boston Bay Group --------------------------------------------------

Roxbury Conglomerate ------------------------------------------- Cambridge ).lrgillite ---------------------------------------------

Lithofacies in the Boston Bay Group ----------------------------

).lge of the Boston Bay Group ------------------------------------

Blue Hills-Quincy and Nahant areas --------------------------------

Structure ---------------------------------------------------------------- Biostratigraphy of the Pennsylvanian of Massachusetts and Rhode Island, 

by Paul C. Lyons ------------------------------------------------------ History of biostratigraphy of the Narragansett Basin -----------'""--------

Floral zonation ---------------------------------------------------------- Fauna of the Narragansett Basin ----------------------------------------

Paleogeographic implications of paleontologic data ----------------------

Rocks of Maine inferred to be Carboniferous, by Robert G. Doyle --------------

Location and geologic setting --------------------------------------------

Description of the unit inferred to be Carboniferous --------------·--------

Evolution of Carbonif~rous terranes in Nevv England, by James W. Skehan, 

S.J., and Daniel P. Murray --------------------------------------------

Paleoenvironment and paleogeography ------------------------------------

Structural evolution of the Narragansett Basin --------------------------

Structural evolution of southeastern Nevv England ------------------------

Timing and causes of the ).llleghanian Orogeny ----------------------------

References cited -------------------------------------------------------------

Ill 

Page 

A1 

2 

2 

2 

4 

4 

9 

10 

12 

13 

13 

13 

14 

15 

15 

17 

17 

17 

18 

19 

19 

19 

19 

20 

20 

20 

20 

23 

23 

24 

24 

24 

25 

25 

25 

25 

26 

26 

26 
IV CONTENTS 

ILLUSTRATIONS 

[Plate follows references cited) 

Page 

PLATE 1. Pecopteris, Erem.oPteris, Alethopteris?, Odontopteris, Neuropteris, and Sphenopteris. 

FIGURE 1. Map showing the area of southeastern New England occupied by deposits known or inferred to be 

Carboniferous ------------------------------·------------------------------------------------------- A3 

2. Geologic map of the Narragansett, Norfolk, North Scituate, and Woonsocket Basins, Massachusetts and 

Rhode Island ---------------------------.:.------------------------------------------------------------ 5 

8. Schematic structural profile across the southern Narragansett Basin ----------------------------------- 6 

4. Map showing metamorphic zones and locations of drill holes and coal sightings in the Narraganset Basin 11 

· 5. Schematic structural profile across the Norfolk Basin -------------------------------------------------- 14 

6. Geologic map of the Worcester area, Massachusetts------------------------------------------------------- 16 

7. Geologic map of the Boston Basin, Massachusetts------------------------------------------------------- 17 

8. Structural profiles across the Boston Basin ------------------------------------------------------------- 19 

9. Map showing flor~l localities in the Narragansett and Norfolk Basins ---------------------------------- 21 

10. Pennsylvanian stratigraphic correlation chart --------------------------------------------------------- 23 

11. Map of Maine showing locations of rocks inferred to be Carboniferous -------------------------------- 24 

TABLE 

Page 

TABLE 1. Description of stratigraphic units in the Narragansett and Norfolk Basins ---------------------------- A7 
THE MISSISSIPPIAN AND PENNSYLVANIAN (CARBONIFEROUS) 

SYSTEMS IN THE UNITED STATESMASSACHUSETTS, RHODE ISLAND, AND MAINE 

By jAMES w. SKEHAN, S.J.,l DANIEL P. MURRAY,1 

J. CHRISTOPHER HEPBURN,2 MARLAND P. BILLINGS,8 

PAUL C. LYoNs, and RoBERT G. DoYLE 4 

ABSTRACT 

In New England, deposits known or inferred to be of 

Carboniferous age are present in five basins in Massachusetts and Rhode Island and in several additional isolated localities in Massachusetts and eastern Maine. Rocks near 

Worcester, Mass., and in the Narragansett and Norfolk 

Basins are dated as Pennsylvanian on the basis of plant 

megafossils. Deposits of the Boston, Woonsocket, and North 

Scituate Basins and the Harvard Conglomerate at Pin Hill, 

Harvard, Mass., are of uncertain age but may be Carboniferous. Rocks within a series ·of graben blocks in eastern 

Maine are inferred to be Carboniferous. 

The Narragansett Basin, Massachusetts and Rhode Island, 

is a structural depression and topographic lowland occupying 

2,460 kma. Rocks dated by plant megafossils as Early to Late 

Pennsylvanian unconformably overlie a Cambrian or Precambrian basement; the Precambrian basement consists 

primarily of 600-~illion- to 650-million-year-old granitic 

rocks cutting older volcanic, volcaniclastic, and plutonic 

rocks. The Middle to Upper Pensylvanian rocks are coal, 

sandstone, conglomerate, siltstone, and shale. Distribution of 

lithologies and sedimentary structures in the approximately 

3,700-m-thick section indicate that most of the sedimentary 

rocks of the five formations that compose the section were 

deposited in a fluvial environment. 

Anthracite and semianthracite are found widely, in seams 

as much as 8 m thick, in the 1,700-km9 part of the basin that 

has undergone lower greenschist-facies metamorphism. These 

coals have very low sulfur contents; have moderate to high 

contents of ash, which is dominantly secondary quartz; and 

yield 13,000 to 14,700 BTU's per ton. 

The Narragansett Basin is characterized by a rich megaflora consisting of 300 nominal species from approximately 

140 floral localities. Nearly all are confined to the Rhode 

Island Formation and range from Alleghenian to Conemaughian (Westphalian C to Stephanian A) or younger. 

1 Weston Observatory, Department of ~eology and Geophysics, 

Boston College, Weston, Mass. 02193. 

D Depnrtment of Geology nn<l Geophysics, Boston College, Chestnut 

Hill, Muss. 02167. 

a Department of Gcologlcul Sclence~c~, Hurn1rd University, Cambridge, 1\Iass. 02139, and North Conwny, N.H. 03860. 

• State Geologist, l\:lnlne Geological Survey, Augusta, Maine 04330, 

Most rocks in the Narragansett Basin are in the lower 

greenschist facies; however, in southern Rhode Island, the 

regional metamorphic grade increases in a short distance to 

upper amphibolite facies and, in at least an indirect way, 

is associated with the late syntectonic ;to posttectonic N arragansett Pier Granite of Permian age. The larger, Massachusetts part of the basin is faulted and mildly folded. In 

contrast: the southern, Rhode Island, section of the basin is 

moderately to intensely deformed and is characterized by 

several generations of folds and faults. 

The Norfolk Basin contains two formations of Pennsylvanian age, the Wamsutta Formation and the Pondville 

Conglomerate; these formations are also present in the adjacent Narragansett Basin. in the Norfolk Basin, these rocks 

are present in a syncline overturned to the southeast and 

are in part bounded by thrust faults. Plant fossils from the 

Pondville suggest a Pottsvillian age, probably equivalent to 

the Westphalian B of Maritime Canada and Europe. 

The W oonsocke.t and North Scituate Basins contain clastic 

sedimentary rocks long correlated with those of the N arragansett Basin; however, they may be much older. The beds 

dip generally to the east, are polydeformed, and are in the 

upper greenschist facies of metamorphism. 

Two small patches of nonmarine phyllite are present near 

Worcester, Mass. Phyllite encloses a 2-m-thick lens of metaanthracite at the "Worcester Coal Mine." To the south, at the 

second outcrop area, a similar phyllite is interbedded with 

coarse stretched-pebble conglomerate, granule conglomerate, 

and arkose. The metamorphic grade is just below .the almandine isograd. On the basis of plant fossils, the rocks are 

assigned an Early to Middle Pennsylvanian ag'e. The H.arvard Conglomerate, an isolated deposit northeast of Worcester, has been considered Pennsylvanian. However, the unit 

is unfossiliferous, and the field relationships have been 

debated. 

The bedrock in and near the Boston Basin may be assigned .to five map units: ( 1) "basement," Precambrian, 

possibly including some Paleozoic; (2) Blue Hills-Quincy 

and Nahant areas, Lower and Middle Cambrian sedimentary 

rocks and Ordovician (?) igneous rocks; ( 3) Mattapan and 

Lynn Volcanic Complexes, possibly as old as Precambrian 

or as young as Pennsylvanian; (4) Boston Bay Group, having a maximum thickness of 5,700 m and consisting of the 

Cambridge Argillite and the Roxbury Conglomerate, which 

is a: southerly lithofacies of the lower part of the Cambridge 

Al 
A2 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Argillite; and ( 5) Triassic ( ? ) diabases. A diamictite (tillite) is present at the top of the Roxbury Conglomerate. 

Because supposed fossils collected from the Boston Bay 

Group may be inorganic, the age of the group is still in 

doubt. On lithologic and tectonic grounds, the group is considered to be Pennsylvanian, but other ages have been 

proposed. 

The strata of the Boston Bay Group are thrown into a 

series of folds, most of which plunge eastward. Five longitudinal faults, some of which dip steeply, are present. One 

transverse fault strikes north. The deformation was late 

Paleozoic. 

Similarities in ages, lithologies, stratigraphy, and structure of the Narragansett and Norfolk Basins and of the 

deposits at Worcester suggest that their origins are related 

and that all these deposits may have been part of a single 

fluviatile, nonmarine basin. The ages of the Boston, Woonsocket, and North Scituate Basins are uncertain. These 

three basins are dissimilar enough from the other basins 

and have lithologies and stratigraphy, in part at least, similar enough to fossiliferous Cambrian rocks to suggest that 

they may be much older than Carboniferous. All five. basins 

and the deposits at Worcester were deformed by folding and 

faulting in the Alleghanian orogeny. 

Sedimentary rocks inferred to be of Carboniferous age 

have been mapped in eastern Maine within a series of graben 

blocks related to segments of the 320-km-long Norumbega 

fault system. The rocks have been tentatively separated 

into two members, arkosic and nonarkosic. The unit consists 

of multicolored bedded and nonbedded siltstone, sandstone, 

arkose, and polymictic conglomerate. No fossils or economic 

minerals have been reported. 

INTRODUCTION 

Deposits of the Narragansett Basin, Massachusetts and Rhode Island, deposits of the Norfolk 

Basin, Massachusetts, and deposits near Worcester, 

Mass., are dated as Pennsylvanian on the basis of 

plant megafossils. Deposits of the Boston, Woonsocket, and North Scituate Basins and the Harvard 

Conglomerate at Pin Hill, Harvard, Mass., are of 

uncertain age but may be Carboniferous. Sedimentary rocks within a series of graben blocks in 

eastern Maine are inferred to be Carboniferous. The 

area in southeastern New England occupied by de .. 

posits known or inferred to be Carboniferous is 

shown in figure 1. 

The stratigraphic nomenclature used in this paper 

has not been reviewed by the Geologic Names Committee of the U.S. Geological Survey. The nomenclature used here conforms with· the current usage of 

the Massachusetts Department of Public Works ; the 

Massachusetts Department of Environmental Quality Engineering Office, of the State Geologist; and 

the Maine Geological Survey, Department of Conservation. 

ACKNOWI.t:I)(;Mt:NTS 

Research in the Narragansett Basin was supported largely by NSF (National Science Foundation) Grant No. AER7602147 and U.S. Bureau of 

Mines Contract No. J0188022; that in the Norfolk 

Basin was supported by NSF Grant No. AER 

7602147. 

We wish to acknowledge the excellent spirit of cooperation among the authors of the several parts of 

this chapter. We are also grateful to members of 

the Narragansett Basin Project who have assisted 

in various phases of the field and laboratory studies, 

particularly Frederick Adinolfi, Robert Bouchard, 

Gregory Gintoff, Jay Jones, Daniel Logue, Anne 

O'Connell, Jonathan Raben, James W. Ring, S.J., 

Peter Rushworth, and Tarin Smith and to Joanne 

Tucker, Sally Sargent, and Bruce Withey who assisted in the preparation of the manuscript and 

illustrations. 

P. C. Lyons wishes to acknowledge Clifford G. 

Grant, who collected the plant specimens illustrated 

on plate 1, and Paul Jappe, who photographed 

them. The identification of N europteris rarinervis 

(pl. 1, fi.g. Q) was made by W. C. Darrah. 

No review of the Carboniferous geology of New 

England would be complete without mentioning the 

late Alonzo W. Quinn, who was the driving force 

behind the systematic mapping and related studies 

in the Narragansett Basin and other parts of New 

England during the last several decades. We wish 

to dedicate these ·papers to this geologist, one of the 

dedicated pioneers of regional geologic studies in 

New England and one who gave substantial moral 

support to the Narragansett Basin Project from 

the beginning and who followed its progress with 

interest and encouragement. 

We thank William R. Barton, Joseph Pecoraro, 

and Joseph Sinnott for their encouragement to the 

senior author to undertake the Narragansett Basin 

Project and for their assistance, as well as that of 

very many people, especially the Hon Margaret M. 

Heckler who supported the project from the beginning, Thomas P. O'Neill III, Lt. Governor of Massachusetts, and the entire New England Congressional 

delegation. Additionally, we acknowledge Russell 

Dutcher, Lincoln R. Page, Nicholas Rast, and especially Irving Sacks for valuable assistance at many 

stages of the project and all the many others too 

numerous to mention who have contributed in important ways. 

NARRAGANSETT BASIN OF MASSACHUSETTS 

AND RHODE ISLAND 

By ]AMEs W. SKEHAN, S.J., and DANIEL P. MuRRAY 

The Narragansett Basin is a structural depression 

and topographic lowland occupying 2,460 km2• Rocks 
MASSACHUSETTS, RHODE ISLAND, AND MAINE 

42°30' t----------

Harvard Conglomerate 

at Pin Hill, Harvard, 

IJ 

/) 

Carboniferous rocks 

near Worcester, Mass. 

AREA OF FIGURE . 1 

0 5 10 20 KILOMETERS 

c::::=t:::=:t==:::i 

Oi::::=::::i:==:ElO:::::===::::l20 MILES 

FIGURE 1.-Area of southeastern New England occupied by 

deposits known or inferred to be Carboniferous. 

A3 
A4 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

dated by plant megafossils as Early to Late Pennsylvanian unconformably overlie a Cambrian or Precambrian basement ; the Precambrian basement consists primarily of 600-million- to 650-million-yearold granitic rocks (Naylor, 1975) cutting older volcanic, volcaniclastic, and plutonic rocks. The Middle 

to Upper Pennsylvanian rocks (fig. 2) are coal, 

sandstone, conglomerate, siltstone, and shale. Distribution of lithologies and sedimentary structures 

indicate that most of the sedimentary rocks were 

deposited in a fluviatile environment. Most of these 

rocks are in the lower greenschist facies ; however, 

in southern Rhode Island, the regional metamorphic 

grade increases in a short distance to upper amphibolite facies and, in at least an indirect way, is associated with the late syntectonic to posttectonic 

Narragansett Pier Granite of Permian age. The 

larger, Massachusetts, part of the basin is faulted 

and mildly folded. In contrast, the southern, Rhode 

Island, section of the basin is moderately to intensely 

deformed and is characterized by several generations 

of folds and faults. 

The first detailed survey of the Narragansett 

Basin was by Shaler, Woodworth, and Foerste 

(1899). More recently, Quinn and Oliver (1962), 

Mutch (1968), and Skehan and Murray (1978) provided comprehensive reviews of the geology of this 

basin and of the many previous reports on it. All 

Rhode Island has been mapped at the scale of 

1:24,000, and these data are available as published 

or open-file reports. This work is summarized on the 

geologic map of Rhode Island (Quinn, 1971). Lyons 

(1977) has mapped the Massachusetts part of the 

basin in reconnaissance at this scale; his maps are 

available at the scale of 1:31,250 (Lyons, 1977). 

BASIN CONFIGURATION 

Recent mapping has resulted in several significant 

changes in our ideas of the shape of the N arragansett Basin (fig. 2): (1) Discovery of a trilobite 

fauna having Acado-Baltic affinities indicates that 

phyllites on Conanicut Island that were previously 

mapped as Carboniferous are Middle Cambrian 

marine metasediments (Skehan, Murray, Palmer, 

and Smith, 1977). (2) The Narragansett Basin may 

extend to the northeast at least as far as the present 

coastline (Lyons, 1977, p. 17) ; moreover, the basin 

may continue some distance beneath the sea north 

of Cape Cod Bay. (3) New floral ages (Brown and 

others, 1978) confirm the previously assumed Pennsylvanian age for the clastic metasedimentary rocks 

along the southwest margin of Narragansett Bay. 

(4) Observations on distribution of glacial erratics 

relative to bedrock indicate that Pennsylvanian depdsits of the Narragansett and Norfolk Basins are 

separated by no more than 1 km near the northeastern corner of Rhode Island, suggesting that the 

two basins were formerly connected. Recent geophysical studies off southern New England (McMaster and Collins, 1978, p. 15) suggest that the basin 

extends 16-22 km south-southwest of Narragansett 

Bay. 

Contacts between Pennsylvanian sedimentary 

rocks and basement rocks along the basin margin 

and within the basin are exposed in only a few localities. In some exposures, the contact is an unfaulted 

unconformity; in others, the Pennsylvanian rocks 

are in contact with basement rocks as a result -of 

faulting (Quinn, 1971; Skehan and others, 1976; 

Lyons, 1977). 

A relatively simple geometry has been assumed 

for the basement-cover configuration (Shaler and 

others, 1899, fig. 8). High-angle normal and lowangle thrust faults are thought to define the ir-

·regular contact in places. A schematic structural 

profile of the southern Narragansett Basin is shown 

in figure 3. 

STRATIGRAPHIC RELATIONSHIPS 

Five formations, now referred to collectively as 

the Narragansett Bay Group (new name), are 

recognized in the Narragansett Basin, the Pondville Conglomerate, the Wamsutta Formation, the 

Rhode Island Formation, the Dighton Conglomerate, 

and the Purgatory Conglomerate. All these consist 

of clastic terrigenous sedimentary rocks. Lack of 

outcrop coupled with rapid facies changes and structural complexities has prevented the construction of 

a detailed stratigraphy for the Narragansett Basin. 

The stratigraphic sequence of these units is the 

same as that presented by Mutch (1968, fig. 2), except for the age assignment of the Purgatory Conglomerate, which may be correlative ·with the Dighton Conglomerate. A previously estimated total 

thickness (Shaler and others, 1899) of 3, 700 m for 

these formations was highly speculative; however, 

it is consistent with stratigraphic sections determined recently from depth to basement under the· 

Narragansett Basin computed from gravity observations (Peter Sherman, written commun., 1978). The 

lithologic characteristics and ages of these formationn are summarized in table 1. 

Pondville Conglomerate.-The type locality for 

the Pondville Conglomerate is in the Norfolk Basin 

at Pondville Station, Mass. (Shaler and others, 1899, 

p. 134-139), where it consists of coarse conglom-
MASSACHUSETTS, RHODE ISLAND, AND MAINE AS 

0 10 15 

0 5 10 

FIGURE 2.-Geologic map of the Narragan.sett, Norfolk, 

North Scituate, and Woonsocket Basins, Massachusetts 

and Rhode Island. Locations of structural profiles (figs. 

20 KILOMETERS 

15 MILEs 

71000' 

r· '~//-/ ,' 

, 

I 

,' IPri 1 

I 

I 

I 

I~ ~ : : J Narragansett Pier Granite 

~ Diamond Hill Felsite 

~ Dighton Formation 

f.'.)i!':~s.li~·.[J Purgatory Formation 

~ Rhode Island Formation 

GJ Bellingham Conglomerate 

~ Wamsutta Formation·· 

EJ Pondville Conglomerate 

Contact or fault-Dashed 

where inferred 

............... Thrust fault 

++ Syncline, showing plunge 

where known 

-t-+ Anticline 

.....y....,. Overturned anticline, 

showing plunge 

-B Line of section shown 

on figure 3 

3, 5) are shown. The complex fold patterns of the southenl part of the Narragansett Basin are not shown. 
A6 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

:::>. 

·-· cB ~· ~ Cl) I .-. s::: 

& :::>. 

g rE I ~ j -· J:l ~ s::: 

0 & ~ 

Cl) g 

~ ~ 

C3 PERMIAN Narragansett Pier Granite 

PENNSYLVANIAN 

;::::·(!)· ··- ::c··- >" I IQl u•m ~·.I I I 

J.· I I 

C/)1 I I &-g . I I I CQ CQ 

s "' I I I ~]i .~-g. I I CQ "' lij co• I 

I 

IQ. 

o"iij 

~ 

g ~ c: c;;• o-. : :~ (!J ~ u I 

~ I I I 

I 

OC::-c::::::I-===:::J4 KILOMETERS 

E X .P L A N A T I 0 N 

HADRYNIAN 

Newport Granite 

HADRYNIAN 

1111 Na:~~n;!~i'ocks undifferentiated 

Volcanic basement complex 

.CAMBRIAN 

.. Unnamed metasediments 

CAMBRIAN(?) 

Mica-chlorite schist 

CAMBRIAN(?) 

Bulgarmarsh Granite 

. HADRYNIAN(?) .,gg· Scituate Group 

Contact 

Fault-Arrows show relative movement 

~ BeddiAg form line 

1St Si 

St-Ky 

G 

Bi 

Chi 

Metamorphic zone boundary 

First sillimanite zone 

Staurqlite-Kyanite 

Gamet 

Biotite 

Chlorite 

FIGURE 3.-Schematic structural profile across the southern 

Narragansett Basin. 
Stratigraphic 

unlt 

Purgatory 

Conglomerate. 

Dighton 

Conglomerate. 

Rhode Island 

Conglomerate. 

MASSACHUSETTS, RHODE ISLAND, AND MAINE A7 

TABLE !.-Description of stratigraphic units in the Narragansett and Norfolk Basins 

Lithology 

Coarse-grained to 

very coarse 

grained conglomerate, interbedded with 

thin sandstone 

and magnetiterich sandstone 

lenses; clasts 

in conglomerate 

are almost entirely quartzite, 

but several 

varieties of 

quartzite are 

present. 

Gray conglomerate 

consisting primarily of 

rounded quartzite cobbles to 

boulders and 

containing 

subordinate 

rounded granite 

cobbles and 

sla·te pebbles; 

very little sand 

matrix; lenses 

of medium 

sandstone form 

less than .20 

percent of 

the unit. 

Gray sandstone 

and siltstone 

and lesser 

amounts of gray 

to black shale, 

gray conglomerate, and coal 

10 m (SO ft) 

thick. Quartz 

forms the 

major components of the 

sandstone 

(Mutch, 1968, 

fig. 6) and 

conglomerate. 

Sedimentary 

and other 

distinguish· 

lng features 

The sandstone 

lenses are 

faintly crossbedded and 

coarser both 

upward and 

downward into 

adjacent 

conglomerate. 

Both fining- and 

coarseningupward sequences are 

present; paleocurrents have 

been defined 

only locally; 

conglomerate is 

relatively less 

abundant than 

in Dighton. 

Approximate 

thickness 

>30m 

( > 100 ft) 

<300-450 m 

( < 1,000-1,500 ft) 

<3,000 m 

( < 10,000 ft) 

Age References 1 

No Pennsylvanian Mosher and 

fl.oro yet known, Wood, 1976. 

but coal pebble is 

present; several 

distintive lower 

Paleozoic 

faunas are 

present in 

quartzite clasts. 

Small isolated Skehan and 

amounts of others, 1976. 

allochthonous? 

nondiagnostic 

plant debt'is. 

Westphalian C Skehan and 

and D and Murray, 1978; 

Stephanian. Lyons and 

Chase, 1976. 
A8 

Stratigraphic 

unit 

Wamsutta 

Formation. 

Pond ville 

Conglomerate. 

THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

TABLE !.-Description of stratigraphic units in the Narragansett a1Ul NOTjolk Basins-Con. 

Lithology 

Interbedded red 

coarse-grained 

conglomerate, 

Hthic graywacke, sandstone, and 

shale; conglomerate layers 

contain felsite 

clasts < 1.2 m 

(4 ft); a few 

lenses of limestone, one 

rhyolite flow, 

and several 

sheets of basalt 

are present. 

At type local- · 

ity (Pondville 

Station, Mass.) : 

interbedded red 

and green 

slate, siltstone, 

arkose, and 

quartzite-pebble 

congl()merate; 

elsevihere may . 

also include 

gray to greenish coarse 

conglomerate, 

most pebbles 

being quartzite, 

but some being 

granite or 

schist; abundant sandy 

matrix; and 

dark-gray 

granule conglomerate containing pebbles 

of smoky quartz 

6 mm (0.2 in.) 

in diameter 

irregularly 

bedded witJl 

sandstone and 

lithic graywacke. 

Sedimentary 

and other 

dlstlngutsh· 

tog features 

Crossbedding and 

interfingering 

of layers is 

characteristic. 

Generally, a basal 

conglomerate is 

absent, and the 

first-deposited 

beds are siltstone or arkosic 

sandstone; however, sandstone 

.and shale of the 

Wamsutta 

Formation or 

Rhode Island 

Formation may 

lie directly on 

older rocks; 

clasts 16-60 em 

( 6-26 in.) in 

diameter. 

Approximate 

thickness 

300m 

(1,000 ft) 

0-160 m 

. (

1

0-500 ft) 

Age 

Partly equivalent 

to the Rhode 

Island Formation as the red 

layers interfinger with 

gray and black; 

contains a few 

plant fossils. 

Westphalian A 

or B. 

References 1 

Lidback, 1977. 

1 These references are In addition to Quinn and Ollver (1962), Mutch (1968), and Quinn (1971), which contain information on all these 

stratigraphic units. 
MASSACHUSETTS, RHODE ISLAND, AND MAINE A9 

erate resting unconformably upon pre-Devonian 

rocks. The conglomerate grades vertically into gray 

sandstone that grades into Wamsutta redbeds. 

However, in the Narragansett Basin, the Pondville consists of discontinuous arkosic beds and, to 

a lesser extent, conglomerate (Mutch, 1968) resting 

unconformably upon basement rocks that are at 

least locally deeply weathered. Its absence along 

most parts of the basin margin may be due to 

faulting or nondeposition. Moreover, where present, 

it grades upward into either the Wamsutta Formation, as in the northwest part of the basin, or directly into the Rhode Island Formation, as in 

southern Narragansett Bay. Finally, we agree with 

Mutch (1968, p. 180-181) that in the Narragansett 

and Norfolk Basins, this unit contains many lithologies (see table 1), but we are continuing the traditional use of the name Pondville Conglomerate 

rather than using the name Pondville Formation. 

Wa~msutta Formation.-The type locality of the 

Wamsutta Formation is at Wamsutta Mills, North 

Attleboro, Mass. (Shaler and others, 1899, p. 144). 

This unit consists of conglomeratic to arkosic redbeds (table 1). Unlike the Wamsutta in the Norfolk 

Basin, the Wamsutta in the Narragansett Basin 

contains a significant amount of volcanic deposits. 

The Wamsutta Formation interfingers with gray 

and black sandstones and shales of the Rhode Island 

Formation. Mutch (1968, p. 187-188) has described 

the Wamsutta in detail. 

Rhode Island Formation.-The Rhode Island 

Formation was originally called the Rhode Island 

Coal Measures (Shaler and others, 1899, p. 134, 159). 

The evolution of the name and a description of the 

rocks that compose the formation were given by 

Mutch (1968, p. 183) and Quinn (1971, p. 39-41). 

The lithologic characteristics are summarized in 

table 1. 

The Rhode Island Formation eonsists largely of 

gray sandstone and siltstone and contains lesser 

amounts of gray to black shale, gray conglomerate, 

and coal (table 1). Calcareous rocks are confined to 

the southwestern metamorphosed part of the basin 

where they are now represented as amphibolite. 

This formation constitutes most of the basin; 

however, because of stratigraphic complexity and 

lack of outcrops, it is not well understood. Ongoing 

work in the basin by the staff of Weston Observatory, Department of Geology and Geophysics, Boston College, is concentrated on the Rhode Island 

Formation (Weston Observatory Staff, 1977). These 

studies involve mapping of outcrops and a geophysical and drilling program whose purpose is to delineate the coal resources of the basin. Early results 

of these studies, including detailed logs of 3,100 m 

of drill core, have provided preliminary information 

on sedimentary cycles and the paleoenvironment of 

the Rhode Island Formation (Skehan and others, 

1976. p. 449-458; Skehan and Murray, 1978). 

Dighton Conglomerate.-The type locality of the 

Dighton Conglomerate is in Dighton, Mass. (Shaler 

and others, 1899, p. 184-187). The Dighton consists, 

for the most part, of cobble conglomerate in the 

cores of three poorly defined synclines (fig. 2 and 

table 1). 

Purgatory Conglorne1·ate.-The type l'Ocality for 

the Purgatory Conglomerate is Purgatory Chasm 

in southern Narragansett Bay. Clasts in the Purgatory are cobble- to boulder-sized quartzite. This 

formation is confined to the southeastern part of the 

basin where it is everywhere deformed into a 

stretched-pebble conglomerate (table 1). In the 

past it has been correlated either with the Dighton 

(Emerson, 1917, p. 55) or with the lower part of the 

Rhode Island Formation (Quinn and Oliver, 1962, 

p. 67). The recent discovery by John Peck (oral commun., 1978) of a well-rounded coal pebble in the Purgatory, although not diagnostic, favors a higher 

stratigraphic position rather than a lower one. We 

believe that now no compelling structural or stratigraphic evidence exists ·for correlating the Purgatory with the lower part of the Rhode Island 

Formation; results of ongoing studies show that the 

Purgatory Conglomerate may be near the top of the 

stratigraphic column (Sharon Mosher, written commun., 1977; Skehan and Murray, 1978). Thus, on the 

basis of recent structural data and lithologic similarities, we believe that the Purgatory is probably 

correlative with the Dighton Conglomerate. 

COAL DEPOSITS 

The Narragansett Basin supported the limited intermittent mining of anthracite from 1808 until 

1959. Studies of this coal were reviewed by Toenges 

and others (1948) and Quinn and Glass (1958). 

Because of energy shortages in New England and 

renewed interest in coal, these coal deposits are 

being reevaluated in a study that relies heavily upon 

moderately deep continuously cored boreholes (Skehan and Murray, 1978). This section summarizes 

the results to date of studies of the coal drilled 

during this program. 

As outcrops of coal-bearing rocks are very scarce 

in the virtually unmetamorphosed part of the N arragansett Basin, only approximately 25 coal occurrences have been recorded (fig. 4) ; most of these 

are prospects or small abandoned mines, and more 
AlO THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

than half of these places were mined. The largest 

mine was at Portsmouth, R.I., and yielded more than 

1 million short tons (Harry Chase, written commun., 1978). 

The locations of completed drill holes, chosen primarily to sample these coal occurrences, are shown 

in figure 4. The coal is anthracite and semianthracite, not meta-anthracite as previously reported. A 

complete description of the chemical and physical 

properties of the coal is contained in Skehan and 

Murray (1978). 

Coal seams sampled during drilling are as much 

as 10 m thick and commonly are internally folded 

and brecciated. The coal has an very low sulfur 

content and is moderate- to high-ash anthracite 

yielding 13,000-14,700 BTU's per ton (as determined from dry samples free of mineral matter). 

Megascopically, the coal has a dull graphitic appearance and is friable. 

Vitrinites are textured and untextured and show 

mosaic structures in some samples and have reflectance values in the range of normal anthracite; 

organic inert components have unusually low reflectances. Mineral matter includes quartz, sericitized 

feldspar, chlorite, illite or muscovite, calcite, pyrite, 

marcasite, chalcopyrite, sphalerite, and rutile. Petrographically, three types of coal are seen : ( 1) normal 

anthracite similar to Pennsylvania anthracite; (2) 

brecciated anthracite having graphitic carbon coating on surfaces of voids and cracks and common annealing textures; (3) natural coke having graphitic 

coating similar to type 2. In both types 2 and 3, the 

secondary carbon acts as a cementing agent. 

These coals are interpreted to have undergone 

coalification to low-volatile bituminous and semianthracite rank. These two ranks were then deformed to produce natural coke and brecciated anthracite, respectively; voids may have formed where 

coal migrated to low-pressure areas. The deformation also released methane that was subsequently 

thermally cracked to produce a carbon-rich gas 

phase. Upon cooling, carbon precipitated out to give 

the graphitic coating now seen, (Ralph Gray, written and oral communs., 1978). This model for the 

evolution of the coals correlates well with the known 

tectonic and metamorphic history of the N arragansett Basin and can also explain many of the previously confusing physical and chemical analyses 

of the coals. 

STRUCTURAL GEOLOGY 

The Narragansett Basin is characterized by two 

structural domains separated approximately along 

the State boundary between Massachusetts and 

Rhode Island. In Massachusetts, the deformation 

was relatively mild, being characterized by northeast- to east-northeast-trending folds (fig. 2) having axial planes dipping moderately to steeply to 

the northwest. In Rhone Island, the deformation was 

more intense and is characterized by mainly northtrending folds. It is not yet clear whether this 

change in trend is accomplished abruptly nea.r the 

head of the Narragansett Bay, approximately along 

the Rhode Island-Massachusetts border, or gradually 

along an arcuate path whose axial region is the area 

noted above. The southern part of the basin is characterized by folds overturned to the west and associated east-dipping cleavage. The northern part of 

the basin, like the northern part of the Norfolk 

Basin (fig. 2), appears to be characterized by less 

intensely deformed folds that are overturned to the 

southeast and by associated northwest-dipping 

cleavage. The rocks of the southern part of the 

basin are lightly overprinted by structures that are 

dominant in the northern part of the basin. The 

Carboniferous rocks of the Narragansett Basin show 

fewer magnetic lineaments than the rest of southern 

New England west of the basin (Barosh and others, 

1977). Those present are extensions of magnetic 

lineaments in older basement rocks. 

Pennsylvanian rocks at several widely separated 

localities, such as the Hanover, Mass., and Middletown, R.I., areas, rest unconformably on older rocks 

of Late Precambrian and Cambrian age. At several 

other widely separated localities, Precambrian and 

Cambrian rocks are in fault contact with Pennsylvanian rocks. Whether the Pennsylvanian rocks 

were for the most part deposited on an extensively 

eroded land surface or in separate faulted basins is 

not yet known. 

Southern Narragansett Basin.-Mapping by 

Mosher and Wood (1976) and Skehan and Murray 

(1978) has shown that the dominant structural features of the southern part of the Narragansett 

Basin are asymmetric westward-verging folds having east-dipping axial-plane cleavage. Closely associated east-dipping, west-directed thrust faults displace Pennsylvanian rocks. Superimposed on these 

earlier formed structures is a less conspicuous cleavage commonly associated with westward-dipping, 

· high-angle reverse faults (Skehan, Belt, and Rast, 

1977; Mosher and Wood, written commun., 1977; 

Skehan and Murray, 1978). Late normal faults cut 

earlier structures (Quinn, 1971, pl. 1). 

A stretched-pebble conglomerate containing extraordinarily elongated pebbles is present in many 

different localities in the southern Narragansett 
MASSACHUSETTS, RHODE ISLAND, AND MAINE 

~i~ 5•LLJ 

~~~ LLJ'U 

Cj<C 

~l~ I 

• 

••• 

• 

•• I . ·-·-·) 

\ 

\ 

• 

Ch 

• • • • 

• • • 0 

• 

0 

• 

• 

Ch 

0 

• 

• 

• 

EXPLANATION 

Ch 

Cht 

. Bi 

G 

Ky-St 

Si--M 

Si--K 

Metamorphic zones 

Chlorite 

Chloritoid 

Biotite 

Gamet 

Kyanite-Staurolite 

Sillimanite-Muscovite 

Sillimanite-K-Feldspar 

• Coal sighting 

o Drill hole 

Q Multiple closely spaced sites 

~ ~ Narragansett Pier ·Granite 

~ Pre-Pennsylvanian Igneous and Metamorphic 

rocks 

-- Metamorphic isograd-Dashed where inferred 

10 15 KILOMETERS 

i=:c:=I::::J=::::::c::::i:==========:::i1 0 MILES 

FIGURE 4.-Me.tamorphic zones and locations of drill holes 

and coal sightings in the Narragansett Basin. 

All 
Al2 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Basin. A classic location is at Purgatory Chasm, 

Aquidneck Island, Rhode Island, the type locality 

of the Purgatory Conglomerate. The longe.st axis is 

typically parallel to the primary fold axis. 

Northern Narragansett Basin.-The regional 

folding pattern in the northern part of the Narragansett Basin is defined chiefly by reconnaissance 

mapping of the Dighton Conglomerate in the eastnortheast-trending Great Meadow and Dighton synclines ·(Shaler and others, 1899 ; Lyons, 1977). The 

intensity of metamorphism and deformation effects 

in the north are far less than in the south. 

Faults.-Faults of several orientations and relative ages have been recognized and mapped in a 

preliminary and reconnaissance fashion (Shaler and 

others, 1899 ; Quinn, 1971 ; Skehan and others, 1976 ; 

and Lyons, 1977). Figure 2 shows a number of such 

faults. 

West-directed, east-dipping thrusts, interpreted 

as early, are· succeeded by west-dipping high-angle 

reverse faults. These compressional faults are considered to be of Alleghanian age. Preliminary mapping by ourselves and by Lyons (1977) suggests 

that the southeastern margin of the basin may be 

controlled by such a fault, although its angle of dip 

is not y~t known. The northeasern part of the basin 

may be a thrust cut by later normal faults (fig. 2). 

At the Masslite Quarry, Plainville, Mass., southeast-dipping thrust faults, cut by later north-striking normal faults, are reco·gnized. This sequence of 

faults suggests that the Pennsylvanian rocks of the 

Narragansett Basin may have been thrust northwestward over the basement and later displaced by 

normal faults. An 865-foot NX-cored hole near the 

quarry shows that the Pennsylvanian sedimentary 

rocks are unconformable on the basement; therefore, 

the above-mentioned thrust faults are in the cover 

rocks. 

The northern margin of the basin (fig. 2) and the 

eastern third of the southern margin are assumed 

to be offset by normal faults that strike generally 

within 20° of north. Quinn (1971) mapped a horst 

block near the southeastern margin of the basin as 

being bound by north-striking faults and as exposing basement rocks of the Metacom Granite. The 

granite is cut by a series of closely spaced eastdipping older thrusts. The western margin of the 

basin at Diamond Hill is marked by a generally 

north-striking silicified fault zone (Quinn, 1971), 

similar in orientation to that in Bristol, R. I. (fig. 2). 

Faults striking generally northwest or northeast 

may be more numerous than previously recognized ; 

offset on the northeast-striking faults may be more 

important than offset on the northwest-striking 

faults. Evidence for the existence and orientation 

of the northwest-striking faults in the southern part 

of the basin consists of (1) various combinations of 

topographic and drainage alinements that in some 

places are associated with subparallel orientation of 

structural elements in the bedrock, (2) offsets of 

bas.in margins, and (3) steplike offsets of shorelines. 

Because these faults have limited demonstrated continuity, they have not been shown in figure 2. 

METAMORPHISM 

The Narragansett Basin has undergone a Barrovian regional metamorphism that increases in intensity to the southwest as shown in figure 4. 

The metamorphic gradient is neither uniform nor 

simple. All the Massachusetts part of the basin and 

part of the Rhode Island part of the basin are in the 

chlorite zone, on the basis of mineral assemblages 

and coal rank. The thermal maximum of this regional metamorphism is roughly centered about the 

contact between the Narragansett Pier Granite and 

Pennsylvanian metasediments. However, in detail, it 

appears that (1) the isograds are oblique to structural trends but are truncated by the granite, and 

(2) the thermal maximum is actually displaced 

somewhat to the north of the granite. Our ongoing 

studies of the southwestern part of the basin suggest that the peraluminous Narragansett Pier 

Granite is anatectic in origin and thus may be one 

of the results of the metamorphism and not the 

cause. 

Radiometric dates on muscovite and biotite from 

the kyanite-staurolite zone indicate a Permian age 

for the metamorphism (Hurley and others, 1960). 

Moreover, sillimanite-bearing mineral assemblages 

in eastern Connecticut may represent the western 

extension of the Alleghanian metamorphism recorded in Rhode Island (Murray and others, 1978). 

Our studies also suggest that sedimentary rocks 

in the southwestern part of the basin record three 

episodes of metamorphism: (1) an early greenschist facies of dynamothermal metamorphism ; (2) 

a later period of static prograde Barrovian facies 

series that peaked at the second sillimanite isograd; 

and (3) a youngest, localized greenschist facies of 

dynamothermal retrograde metamorphism. 

Because of the availability of thousands of meters 

of drill core from Massachusetts and northern 

Rhode Island and abundant sea cliff exposures, roadcuts, and drill core from construction sites in the 

southwestern part of the basin, we have begun a 

study of the effects of progressive metamorphism 

and deformation on coal and associated rock under 

a wide range of conditions (D. Murray, J. Rehmer, 
MASSACHUSETTS, RHODE ISLAND, AND MAINE A13 

and J. C. Hepburn, unpub. data, 1978). Because of 

the sensitivity of coal to changes in temperature, 

pressure, and other factors, study of this area 

promises to yield valuable insights into regional 

metamorphic processes. 

IGNEOUS ACTIVITY 

Both extrusive and intrusive igneous rocks are 

present within or adjacent to the Narragansett 

Basin. The former are limited to felsic and mafic 

flows within the Wamsutta Formation in the Attleboro area. Moreover, the Wamsutta contains a relatively high percentage of volcanic detritus, implying 

the presence of abundant volcanoes during its formation (Mutch, 1968). 

The subsolvus Narragansett Pier Granite intrudes 

the southwest margin of the Narragansett Basin. 

Away from the contact with the sedimentary rocks, 

this pink granite contains abundant biotite and subordinate muscovite. Near the Pennsylvanian sedimentary rocks, the granite is white, and muscovite 

plus garnet are common (Kocis and others, 1977, 

1978). Recently obtained paleontologic dates from 

xenoliths within the granite (Brown and others, 

1978) and radiometric dates from monazites. (Kocis 

and others, 1978) confirm the previously assumed 

Permian age for the granite. 

Other Permian plutonic events are probably represented by pegmatites found throughout southern 

New England (Zartman and others, 1970) and by 

the granite in southern. New Hampshire (J. B. 

Lyons, oral commun., 1978). 

AGE RELATIONSHIPS 

Radiometric dates coupled with the abundant 

floral dates allow a precise definition of the Alleghanian ·Orogeny as recorded in the Narragansett 

Basin. Floral dates· indicate that deposition of sediments began in early Pottsvillian (Westphalian B) 

time and persisted at least through Conemaughian 

(Stephanian A) time. Moreover, at least several 

hundred meters of Rhode Island Formation plus the 

Dighton Conglomerate lie stratigraphically above 

the Stephanian A (or younger) dated rocks. This 

stratigraphic succession suggests that deposition 

probably continued well into Conemaughian (Stephanian A) time and possibly into early Monongahelan (Stephanian B) time (280 million years ago). 

Mutch (1968, p. 198) summarized radiometric 

data collected through the mid-1960's. Most of these 

ages should be used with caution because they are 

either (1) anomalously old (because of older inherited ages in detrital material) or (2) anomalously young (because of migration of radiogenic material). Of the ages listed in Mutch's review, the 

Rb/Sr biotite and K/ Ar whole-rock ages of Hurley 

and others ( 1960) are probably the most useful. 

These, as well as other ages, were obtained by them 

from biotite-staurolite-garnet schist on Conanicut 

Island, southern Narragansett Bay, and indicate 

that the major progressive metamorphism took 

place 260± 13 m.y. (million years) ago. The somewhat younger (=230 m.y.-250 m.y.) K/Ar biotite 

ages also given may represent ages of cooling or 

uplift. 

Recently, the Narragansett Pier Granite was 

dated at 276 m.y. on the basis of U-Pb ages on 

monazites (Kocis and others, 1978). Dikes of the 

Westerly Granite, a homogeneous peraluminous 

granite, cut the western part of the Narragansett 

Pier Granite and have been dated at 240 m.y. (Hurley and others, 1960). This also may represent a 

cooling age, rather than the age of a much younger 

intrusion. 

Taken together, the age relationships suggest 

that deposition of sediments began in Upper Pottsvillian (Westphalian B) and continued at least 

through Conemaughian time (Stephanian A). The 

deposits were buried, deformed, and metamorphosed 

by 260 m.y. ago .. The lntrusions of the granites were 

virtually contemporaneous at 276 m.y. ago. K/ Ar 

ages in the range of 230 my. to 250 m.y. may record 

uplift or cooling. 

NORFOLK BASIN OF MASSACHUSETTS 

By DANIEL P. MURRAY and JAMES W. SKEHAN, S.J. 

The Norfolk Basin is a northeast-trending basin 

that extends from the northwest margin of the 

Narragansett Basin toward the Boston Basin (fig. 

2). The Norfolk and Narragansett Basins are now 

separated. by about 1 km but were probably connected prior to the formation of the present erosion 

surface and therefore are shown as one basin in 

figure 2. Most of the Norfolk Basin is within the 

Norwood and Blue Hills quadrangles, which were 

mapped by Chute (1964, 1966, 1969). The sedimentology of one of the major outcrops in this basin was 

the subject of a detailed study by Stanley (1968). 

Stratigraphic relationships.-The Pennsylvanian 

rocks of the Norfolk Basin consist of two units, the 

Pondville Conglomerate and the Wamsutta Formation. The Pondville is subdivided into a lower boulder 

conglomerate member and an upper member of gray 

coarse sandstone to pebble conglomerate. On the 

basis of plant megafossils, the upper member has 

been dated as late Pottsvillian (Lyons and others, 
A14 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

1976). The upper member grades upward into the 

Wamsutta which, except for the absence of volcanic 

deposits, is similar to the formation as exposed in 

the Narragansett Basin. A subaerial paleoenvironment had been previously assumed for the Wamsutta on the basis of the red color and presence of mud 

cracks (Stanley, 1968). However, the redness of 

deposits is no longer considered sufficient to indicate a subaerial origin (Van Houten, 1973), and the 

cracks are reinterpreted by the authors to be dewatering structures. The Wamsutta is thought to 

represent outwash or sheet deposits on flood plains 

that formed adjacent to alluvial fans (now seen as 

the coarser grained Pond ville Conglomerate) . 

Structure and metatnorphism.-The dominant 

structural feature of the Norfolk Basin is a northeast-trending syncline overturned to the southeast ; 

this mainly defines the shape of the basin. Several 

high-angle north-striking faults also cut the basin 

(Lyons, 1977, Map B-24). However, the displacement on them is not great. The Pennsylvanian rocks 

are in part bounded by thrust faults. A schematic 

structural profile across the Norfolk Basin is shown 

in figure 5. The entire basin is in the lower greenschist facies. 

WOONSOCKET AND NORTH SCITUATE BASINS 

OF MASSACHUSETTS AND RHODE ISLAND 

By JAMES W. SKEHAN, S.J., and DANIEL P. MURRAY 

The rocks of the Woonsocket and North Scituate 

Basins (fig. 1) have long been correlated with rocks 

at Bellingham, Mass. (Mansfield, 1906, p. 99), referred to as Bellingham Conglomerate (Hall, 1963, 

p. 53). The rocks of these basins consist of gray to 

green conglomerate, sandstone, lithic graywacke, 

and phyllite, all irregularly interbedded (Quinn, 

1971, p. 42). In the Woonsocket Basin, the dominant quartzite pebbles are elongate, but in the North 

Scituate Basin, pebbles are less elongate, conglomerate is less abundant, and sand-size grains are predominant (Quinn, 1971, p. 42). 

:Structure and metamorphism.-Two _alternate 

interpretations of the structure of these basins are 

presently permissible: (1) On the basis of a general easterly dip and discordance of the basin rocks 

with the structure of the older rocks, the eastern 

borders may be a fault (Richmond, 1952) ; or (2) 

the basins may be large infolded synclines, overturned to the northwest. These garnetiferous rocks 

are in the upper greenschist facies. 

On the basis of preliminary structural studies by 

Hall (1963, p. 53), two and probably three phases of 

deformation are recognized. The first phase of folding warped bedding around northeast-plunging 

axes (B1) and caused the formation of an eastdipping axial-plane schistosity ; a mica lineation, 

quartz rods, and stretched pebbles are all parallel 

to the fold axes. The second phase warped the axialplane schistosity of B1 folds in an east-northeast 

direction and caused the formation of a new schistosity and a "crinkle" lineation due to intersection of 

the two schistosities. A third phase apparently 

folded the first schistosity as well as the pebbles 

and warped the crinkle lineation. 

Age.-The rocks of the Woonsocket and North 

Scituate basins may be correlative with those of the 

Narragansett Basin. We suggest the alternative posffH ffH 

S~L~a 200=~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~200 S~L~a 

400. 400 

800 800 1~· 1~ 

0 2 ·MILES cc~~~~~========~ 

EXPLANATION 

H:~?~~~ Wamsutta Formation 

~ 

~ Pondvllle Conglomerate 

Dedham Plutonic Complex 

Sharon Syenite 

Contact 

Fault-Arrows show relative movement 

FIGURE 5.-Schematic structural profile across the Norfolk Basin. 
MASSACHUSETTS, RHODE ISLAND, AND MAINE AlS 

sibility that they may be much older. Because these 

two basins may be virtually in the same structural 

position as the Boston Basin with respect to the 

authenticated Carboniferous basins, an understanding of the age of any of these basins' sedimentary 

rocks may apply to the others. 

DEPOSITS NEAR WORCESTER, MASS. 

By J. CHRISTOPHER HEPBURN 

Two small patches of nonmarine Carboniferous 

rocks near the city of Worcester in east-central 

Massachusetts are shown by one symbol in figure 

1. Pennsylvanian-age plant fossils have been identified from the northern outcrop area. 

Lithology.-Gray to dark-gray, very carbonaceous slate or phyllite is the predominant rock in 

the northern outcrop area (fig: 6). One 2-m-thick 

lens of very impure, shiny, black meta-anthracite 

is present within the phyllite at the site of the longabandoned "Worcester Coal Mine." A similar phyllite 

is also present in the poorly exposed southern outcrop area (fig. 6) where it is interbedded with 

coarse stretched-pebble, polymict conglomerate, 

feldspathic granule conglomerate, and arkose. The 

clasts in the conglomerate are in a shaly matrix. 

Structure and metamorphism.-The Carboniferous rocks of the Worcester area are moderately to 

steeply dipping, and the finer grained rocks show a 

secondary slip cleavage. Electron-microprobe analysis of small garnet porphyroblasts in the phyllite 

show them to have appreciable MnO (as much as 

9.1 weight percent). Thus, the grade of metamorphism is somewhat below that for the normal almandine isograd. 

Age.-The "Worcester Coal Mine" has long been 

of geological interest and has been visited by such 

luminaries as E. Hitchock, Lyell, and Agassiz. Fossils were first found in 1883 supposedly in response 

to a remark by Agassiz of "Where are the fossils?" (Perry and Emerson, 1903, p. 18). Grew, 

Mamay, and Barghoorn, in the most recent summary of the plant fossils, indicate that they "are 

clearly of Carboniferous age and most likely of the 

Pennsylvanian Period" (1970, p. 122) and that they 

most likely can be assigned a Pottsville age. However, P. C. Lyons (in Grew, 1976, p. 395) suggested 

that the flora is Alleghenian (Westphalian C) in 

age, that is, younger than Pottsville (fig. 10). 

The granite-pebble conglomerate in the southern 

outcrop area contains clasts of the adjacent bluequartz-bearing Millstone Hill Granite which has 

been dated at 345 ± 15 m.y. (Zartman and others, 

1965). Therefore, the conglomerate containing this 

granite must be of Carboniferous age. 

Correlation.-Because no readily observable 

structural or metamorphic breaks exist between 

these poorly exposed Pennsylvanian rocks and the 

surrounding rocks, Emerson (1917), in his summary 

of Massachusetts geology, assigned a Carboniferous 

age to many of the rocks in central Massachusetts. 

Recent detailed mapping in the Worcester area 

(Grew, 1973; Hepburn, 1976; J. C. Hepburn and E. 

S. Grew, unpub. data, 1977) has shown that the 

Pennsylvanian deposits are restricted to two small, 

largely fault-bounded basins. The nomenclature of 

the Pennsylvanian rocks of .the Worcester area is 

in a state .of flux at present. The Worcester Phyllite 

in the original formational designations (Emerson, 

1917; Perry and Emerson, 1903) included both 

Pennsylvanian and what are now believed to be 

pre-Pennsylvanian rocks. Probably, the name Worcester Phyllite will be restricted to the pre-Pennsylvanian rocks (Hepburn, 1976) and a new designation will be given to the Pennsylvanian rocks. 

Whether the conglomeratic units in the Pennsylvanian of the Worcester area are similar in age to, and 

can be correlated with, the Harvard Conglomerate 

to the northeast is still not clear. 

The Pennsylvanian rocks of the Worcester area 

probably once were continuous with rocks of similar 

age in the Narragansett and Norfolk Basins and 

likely were deposited under similar conditions. 

Harvard Conglomerate at Pin Hill.-An isolated 

deposit of the Harvard Conglomerate at Pin Hill in 

Harvard, Mass. (fig. 1), has been considered Pennsylvanian in age (Emerson, 1917; Thompson and 

Robinson, 1976). However, the unit is unfossiliferous, and the field relationships have been debated. 

BOSTON BASIN, MASSACHUSETTS 

By MARLAND P. BILLINGS 

The Boston Basin is a lithologic-tectonic unit that 

trends east-northeast, is 50 km long, and is 25 km 

wide (fig. 7). The basin is also a topographic lowland, bounded on the north by the Fells Upland 

and on the south by the Blue Hills and Sharon Upland (LaFor,ge, 1932, p. 8). On the east, the Boston 

Basin is submerged by Boston Harbor and Boston 

Bay, but on the southwest, it merges imperceptibly 

with the Needham Upland. 

The most recent summaries of the bedrock geology 

by Billings (1976a, b) and other pertinent articles 

are in Lyons and Brownlow (1976) and New England Intercollegiate Geological Conference (1976). 
A16 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

EXPLANATION 

~::·.~:::~ Pennsylvanian rocks 

m Silurian-Devonian granitic 

rocks 

I 

I 

l 

I 

I 

I I SDs...~l Silurian-Devonian 

metasedimentary 

rocks 

\ 

fJire?.J Early Paleozoic 

metasedimentary 

rocks 

fJ?:~~.?.] Late Precambrian 

metasedimentary 

rocks 

-- Contact-Dashed where 

approXimate; dotted 

where inferred 

-- Fault-Dashed where 

approximate; dotted 

where inferred 

Worcester Center 

0 

SDs 

/ 

/ 

\ 

\ 

\ 

\ 

\ 

\ 

' I 

I 

J 

~ 

/ 

/ 

/ 

/ SDs 

I 

I 

I 

SDs 

.SDs 

1 MILE 

FIGURE 6.-Geologic map of. the Worcester area, Massachusetts. 

\, 

\1 SDs 

\ 
MASSACHUSETTS, RHODE ISLAND, AND MAINE Al7 

\ 

\ 

' 'I/ 

41° 

15' \\ 

« 

0 ' 

' 

c:, 

' \ 

\ 

-

' I'-

p£ 

I \ 

\ 

1 2 

5 KILOMETERS 

I' I 3 5 MILES 

FIGURE 7.-Geologic map of the Boston Basin, Massachusetts. Structural profiles 

along lines AB, CD, and EF are shown in figure 8. Symbols are shown on p. A 18. 

LITHOLOGY 

In this paper, the rocks will be described as belonging to the following units: ( 1) "basement," 

(2) Mattapan and Lynn Volcanic Complexes, (3) 

Boston Bay Group, and ( 4) rocks of the Blue 

Hills-Quincy and Nahant areas. The Triassic ( ?) 

diabase is not shown and is not discussed in figure 7. 

"BASEMENT" 

A description of "basement" rocks is beyond the 

scope of the present paper. The reader is referred 

to Emerson (1917), LaForge (1932), Bell and Alvord (1976), Castle and others (1976), and Nelson 

(1975). Within the limits of figure 7, many or all 

rocks in the "basement" are Precambrian ; some may 

be Paleozoic. 

MATTAPAN AND LYNN VOLCANIC COMPLEXES 

The Mattapan and Lynn Volcanic Complexes are 

chiefly hard dense white, pink, and red rhyolites, 

often called felsite locally. The less abundant melaphyres are dark green to light green and are composed largely of such secondary minerals as albite, 

hornblende, and epidote. Some trachytes and andesites are present (Emerson, 1917, p. 204). Pyroclastic rocks include crystal tuff, lapilli tuff, breccia, 

and lahars (Nelson, 1975). Although much of the 

material in the Lynn and Mattapan Volcanic Complexes appears to have been erupted on the surface 

as flows, ashfalls, and ashflows, it has long been 

known that many bodies occupy vents and dikes 

in the older rocks, such as the Dedham Granodiorite. 

The Mattapan is 600 m thick in Hyde Park (Billings, 1929, p. 104); data given by Nelson (1975) 

indicate that it is at least 760 m thick in Dover 

and Natick. But in places, as in Hingham and 

Nantasket, the formation is absent. In 1929, I (Billings, 1929, p. 104) thought that an angular unconformity separated the Mattapan from the overlying 

Roxbury. 
A18 

Q) c -

<tiP 0 

·!il Ill 

§ § 

"'6Jt.L. 

c,m 

8 i7l 

~ ~ '"0~ 

c£-g Ill 

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:g~ 

15~ 

~.!( 

u 

0. 

::::1. 

e 

<.:) 

:::>, ~ Ill !il al E c 0 .9 "'6l 

c8 c 

0 

u 

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~ 0 

0:::: 

c Kl 5-x 

...J.£!! 

'"00. 

c E Ill 0 

1a -~ ~@ 

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THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED .STATES 

EXPLANATION 

Figures 7 and 8 

~ ' 

~ 

E ... 2] 

la E ::I Q) C'::E 

Cf) 

i 

-5 

8~ '"0'.0 

16 § 

~::E 

::§! 

l 

~ ./ 

*May be as old as Precambrian or 

as young as Pennsylvanian 

---Contact 

Fault-Dashed where inferred 

-?- High angle; queried where doubtful 

-----.... Thrust; sawteeth on upper plate 

A--B Line of section-Sections shown on 

figure 8 

~ z 

~ 

~ Cf) 

2 

g: 

z 

~ 

~ 

Cf) 

~ 

z 

r5 

0.. 

* 

0:::: 

~ :::> 

d 

Cf) 

~ ~ al O:::~U 5 

~ 8 u 0:::: 

0 

~ R.' 

0:::: g 

rooo 

u ~~~ I.Ll 

~ ~ 

These volcanic complexes are younger than the 

Dedham Granodiorite, which is 608 ± 17 m.y. or 

latest Precambrian (Dowse, 1950; Kovach and 

others, 1977). Moreover, the pronounced unconformity between the volcanic complexes and the 

Dedham (LaForge, 1932, p. 31) indicates deep 

erosion after the emplacement of the Dedham and 

the eruption of the volcanic ·complexes. R. E. Zartman has recently obtained a zircon age ot 580 

m.y. from a rhyolite in the Mattapan Volcanic Complex (E-an Zen, written commun., 1977). Such 

ages are questionable (Higgins and others,. 1977), 

especially for a rock that is present in vents. LaForge ( 1932, p. 33) said that the Lynn "is cut by 

the Quincy granite type." Zartman and Marvin 

(1971) dated the Quincy as 437±32 m.y. (latest 

Ordovician). 

If the Mattapan can be correlated with the volcanic rocks in the Blue Hills, as Chute (1969) assumed, then it is latest Ordovician. The radiometric 

dates are consistent with assigning the Mattapan 

and Lynn Volcanic Complexes to the Cambrian or 

Ordovician. 

The Newbury Volcanic Complex is dated by fossils as latest Silurian and possibly earliest Devonian 

(Shride, 1976, p .. 147). This complex can be traced 

to within 13 km of the Lynn Volcanic Complex. The 

Newbury and Lynn are lithologically similar. On 

the basis of dubious paleontological evidence, Pollard ( 1965) suggested that the Mattapan is Mississippian. Rhyolite and melaphyre similar to those 

in the Mattapan and Lynn Volcanic Complexes are 

present in the Alleghenian (Pennsylvanian) Wamsutta Formation of the Narragansett Basin ( Emerson, 1917). The possibility that the Mattapan and 

Lynn may be as old as Precambrian or as young as 

Pennsylvanian is adopted in figure 7. 

BOSTON BAY GROUP 

Perhaps the most striking ne'w interpretation of 

rocks in the Boston Basin is that the Roxbury 

Conglomerate is a southerly facies of the lower part 

of the Cambridge Argillite. The rocks of the Boston 

Bay Group are relatively unmetamorphosed, although some chlorite is present. The maximum 

thickness of 5,700 m is found in the northern half 

of the basin, but toward the south, the known thickness is only 1,600 m. The group is probably Pennsylvanian, although many geologists would accept 

a much older age. An excellent concise tabular summary of the lithology is given in Rehmer and Roy 

(1976, p. 72). 
MASSACHUSETTS, RHODE ISLAND, AND MAINE A19 

ROXBURY CONGLOMERATE 

The Roxbury Conglomerate is a complex assemblage of nonmarine conglomerate, shale, sandstone 

quartzite, arkose, melaphyre, and diamictite. Most 

of the rocks, except the diamictite, are present 

throughout the formation. The division into members is based on the relative abundance of the 

various lithologic types. From bottom to top the 

three members are: Brookline, Dorchester, and 

Squantum. The compositions and distinctive features of these members were described by Billings 

(1976a) and by Bailey, Newman, and Genes (1976). 

The Brookline Member ranges from 300 to 1,310 m 

in thickness. The Dorchester Member ranges from 

84 to 485 m in thickness. Its top is usually defined 

by the distinctive diamictite of the Squantum Member which many geologists consider to be a tillite 

(Rehmer and Roy, 1976; Bailey and others, 1976; 

Wolfe, 1976). The Squantum ranges from 19 to 122 

m in thickness. 

CAMBRIDGE ARGILLITE 

In the southern part of the Boston Basin, where 

the Cambridge Argillite is above the Squantum 

Member of the Roxbury Conglomerate, the Cambridge is 2,500 m thick. In the northern part of 

the basin, where the lower part of the formation 

Fells Upland 

z 

a: a:,_ UluJ..J 

~O:J 

!§ !§ if: CHARLES RIVER SYNCLINE 

C Sml z m IPc 

is interpreted as a facies equivalent of the Roxbury 

Conglomerate, the Cambridge is 5,700 m thick. The 

"Milton Quartzite" (Billings, 1929, 1976a) is a 

white seric.itic quartzite that is 150m thick and that 

lies 850 m above the Squantum Member. 

LITHOFACIES IN THE BOSTON BAY GROUP 

The facies relationship shown in figure 8 is based 

largely on observations in the City Tunnel Extension (Billings and Tierney, 1964). The axis of 

the Charles River syncline coincides in this diagram 

with the northern limit of the Squantum Member. 

In the south limb of the syncline, the Squantum 

and Dorchester Members, as well as the upper 

part of the Brookline Member, are exposed. But 

where these units should appear on the north limb 

they are replaced by the Cambridge Argillite. More: 

o~e~, on the south limb, many beds of gray argillite, 

Similar to those in the Cambridge Argillite are 

present in the Dorchester Member. Details are ~iven in Billings and Tierney (1964, fig. 9). 

AGE OF THE BOSTON BAY GROUP 

For 77 years, the age of the Boston Bay Group 

has been based on supposed fossils found by Burr 

and Burke ( 1900) in the Roxbury Conglomerate. 

o· 1 2 3 4 5 KLOMETERS 

~ I ; I I ~ I 

I 

1 ~MILES 

FIGURE B.-Structural profiles across the Boston Basin along 

lines AB, CD, and EF shown in figure 7. Symbols are the 

same as those used in figure 7. 
A 20 THE MISSISSIPPIAN AN'D PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

LaForge (1932, p. 38) said: "Except for a few 

short pieces of tree trunks, of which not even the 

genus can be certainly determined and which may 

be either Devonian or Carboniferous, no fossils 

have been found in these rocks." These specimens 

were lost for many decades, but one of them was 

found about 20 years ago in the Harvard paleobotanical collections. Rahm (1962, p. 329) said: 

"kccording to Professor Elso Barghoorn (personal 

communication) the specimens are either Callixylon 

or Cordaites, genera which together span a . period 

from the Upper Devonian to the Permian." Professor ·Barghoorn (oral commun., 1977) has recently 

concluded that the specimen is inorganic. Bailey and 

Newman (1978) also consider the specimen to be 

inorganic, but their_ proposed mechanism for such 

an origin is not satisfactory. Under the circumstances, reliable paleobotanical evidence for dating 

the Boston Bay Group is lacking. 

The Roxbury Conglomerate is younger than the 

Dedham Granodiorite and the Mattapan Volcanic 

Complex, as many of the clasts in the Roxbury 

were derived from the :pedham and Mattapan. If, 

as I ·believed earlier (Billings, 1929), the Mattapan 

and Lynn Volcanic Complexes are unconformable 

beneath the Boston Bay Group, their age tells us 

only that the Boston Bay Group is younger~ However, I agree that the evidence for an unconformity 

should be restudied. 

The most compelling argument on the age of the 

Boston Bay Group is based on the extensive conglomerate in the Boston Bay Group. In the N arragansett and Norfolk Basins, the only paleontologically dated conglomerate of the kind found 

in the Roxbury Formation are Pennsylvanian, thus, 

it seems that tectonic conditions favorable for deposition of "molasse" existed in eastern New England only in the Pennsylvanian. 

BLUE HILLS-QUINCY AND NAHANT AREAS 

The Blue Hills-Quincy area (fig. 6) contains Lower and Middle Cambrian sedimentary rocks and four 

mappable igneous units: (1) a volcanic complex 

(Mattapan Volcanic Complex?), (2) "rhombenporphyry," (3) Blue Hills ·granite porphyry, and 

(4) Quincy Granite (Billings, 1976a). The Nahant 

area. contains Lower Cambrian sedimentary rocks 

and the Nahant Gabbro (Billings, 1976a). 

STRUCTURE 

A more complete discussion of the geological 

structure of the Boston Basin has been presented 

previously (Billings, 1976a, b). Many of the structural features are apparent from the geological 

map (fig. 7) and structural sections (fig. 8). In 

order to be more objective, in figure 7 the longitudinal faults in the southern part of the basin are 

shown as steep (essentially vertical) faults without 

any indication of their genesis. But I still believe 

that they are thrusts, originally dipping south, 

that have been rotated to their present attitude. 

Age of Deformation.-The deformation in ~he 

Boston Basin is presumed to be the same age as 

that in the Norfolk and Narragansett Basins, that 

is, post-Pennsylvanian and older than the Triassic 

Medford Dike. 

BIOSTRATIGRAPHY OF THE PENNSYLVANIAN 

OF MASSACHUSETTS AND RHODE ISLAND 

By PAUL C. LYONS 

The Narragansett Basin has a rich megaflora consisting of about 300 nominal species, nearly all of 

which are from the Rhode. Island Formation; 31 of 

these were considered new species or genera by 

previous workers. The uppermost formation, the 

Dighton Conglomerate, does not have a known 

florule. Animal fossils, principally insects and amphibian tracks, have been found, but these are of little stratigraphic importance because of the scarcity 

of discoveries. Microfloral remains have not been 

found in the coal or adjacent strata of the Rhode 

Island Formation. Because structural complexities 

and facies changes in many parts of the N arragansett Basin interrupt the continuity of the beds, a 

floral zonation scheme is essential for clarification 

of the physical stratigraphy. 

HISTORY OF BIOSTRATIGRAPHY OF THE 

NARRAGANSETT BASIN 

Some of the earliest contributions to American 

paleobotany were based on specimens collected during coal mining operations in the Narragansett 

Basin (Brongniart, 1828-1838; Jackson, 1840; E. 

Hitchcock, 1841; Teschemacher, 1847). No attempt, 

however, was made to relate the megaflora to the 

physical stratigraphy until C. H. Hitchcock (1861) 

correlated the floral assemblages identified by Lesquereux with the stratigraphic section exposed in 

the vicinity of Newport, R.I. This first correlation 

of biologic and rock data was documented by Lyons 

and Darrah (1977) who concluded that the assemblage in the upper part of the Newport section was 

of Stephanian age and referable to the Aquidneck 

shales of Foerste (in Shaler and others, 1899) . 
THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES A21 

71"00' 

_., 

, ,' . ___ , t'~ • ,, 

70 

® 

O~E3!5: .... 5~=:::::1C:O =:;:::::::1e:5 =:::::::i20 KILOMETERS 

O'E ==~...i5i:::::====1:c:O===:::::::i15 MILES 

EXPLANATION 

® Westphailan D-Stephanlan 

• Westphalian C 

~ Westphalian B 

Undifferentiated 

42 

.•... 

Late Carboniferous 

Locality numbers refer to 

unpublished data of 

P. C. Lyons and Jay Jones 

(1978) 

Contact or fault-Dashed 

where inferred 

Thrust fault 

Syncline, showing plunge 

where known 

Anticline 

Overturned anticline, 

showing plunge 

FIGURE 9.-Florallocalities in the Narragansett and Norfolk 

Basins. 
A22 MASSACHUSETTS, RHODE ISLAND, AND MAINE 

The Aquidneck shales are here referred to the upper part of the Rhode Island Formation. 

Brongniart's (1828-1838, p. 303) specimens of 

Pecopteris arguta Brong. (==P. feminaeformis 

Schloth.) apparently came from the roof shales of 

the coal beds mined at Portsmouth, R.I. (fig. 9, loc. 

42) . The Portsmouth coals were assigned to the 

Aquidneck shales (Shaler and others, 1899). Coal 

mining began here in 1809, and these coal beds 

yielded approximately 2 million tons of coal by 

the end of the century. A similar amount of coal is 

still unmined (H. B. Chase, oral commun., 1977). 

Further contributions to the flora of the coalbearing Rhode Island Formation were made later 

in the 19th century (Jackson, 1851; Lesquereux, 

1880-84, 1884, 1889; Clark, 1884; Fuller, 1897; 

Providence Franklin Society, 1887; Shaler and 

others,· 1899). These authors provided lists of 

species but little analysis of the stratigraphic positions of these floras. 

Weston (1917) and Round (1920) presented many 

photographs and sketches of the flora of the N arragansett Basin. Weston;s thesis (1917) contained 

little stratigraphic or locality data. Round's thesis 

(1920) provided generalized locality information 

indicating that her work was based mainly on 

specimens derived from the lower part of the Rhode 

Island Formation, including the Pawtucket (fig. 9, 

loc. 10) and Valley Falls coal beds (fig. 9, loc. 1). 

She concluded that the flora examined was similar 

to that in the Lower Allegheny. Later, Round (1921, 

1922a, b) reported taxonomic data on selected 

species or genera in the basin and correlated (1924, 

1927) the flora with those in New Brunswick, Canada, and Henry County, Mo. 

During the 1930's, Darrah and his students collected specimens from Perrin's Crossing in Seekonk, 

Mass., (fig. 9, loc. 14). The variety of pecopterid 

species reported by Darrah (1969) and the presence 

of Sphenophyllum oblongifolium in these collections 

are evidence of a Late Pennsylvanian (roughly 

Stephanian) age fpr the beds exposed near Perrin's 

Crossing. A stratigraphic section of these beds assigned to the upper part of the Rhode Island Formation is given in Lyons and Chase (1976). Darrah 

(1969) noted the absence of the Neuropteris 

scheuchzeri-N europteris ovata association from this 

florule and from the Mount Hope coal beds, that is, 

the coals mined at Portsmouth, R.I. (fig. 9, loc. 42). 

Knox (1944) reported an important florule from the 

Wamsutta Form·ation (fig. 9, loc. 56) in the same 

area in Attleboro where amphtbian tracks were discovered by Woodworth (1894). Knox (1944) did 

not provide photographs or taxonomic notes, but he 

listed species or genera from the Wamsutta that 

are also found in the lower part of the Rhode Island 

Formation. These taxa include N europteris cf. 

rarinervis, Asterophyllites (Calamocladus) equisetiformis, and Sphenopteris species; only one Pecopteris sp. was found in the Wamsutta. He concluded 

that the Wamsutta assemblage was similar to that 

in the Lower Allegheny and equivalent to that in 

the lower part of the Rhode Island Formation. 

Other florules assignable to the lower part of the 

Rhode Island Formation were ·reported by Lyons 

(1969, 1971) from Foxboro (fig. 9, loc. 24), by 

Oleksyshyn (1976) from Plainville (fig. 9, loc. 20), 

and by Lyons and Chase (1976) from these two 

localities and from Mansfield (fig. 9, loc. 16). Lyons 

and Darrah (1978) have documented a younger 

floral zone within the Rhode Island Formation at 

Easton, Mass. (fig. 9, loc. 70). This assemblage 

consists of 40 species and is dominated by pecopterids: Pecopteris arborescens (pl. 1, figs. A, E), 

very common; P. lamuriana (pl. 1, fig. F) and P. c.f. 

lamuriana (pl. 1, fig. H), common; P. aff. hemitelioides (pl. 1, figs. D, G) ; P. unita (pl. 1, fig. 

C) ; and other pecopterids (pl. 1, figs. B, I). Odontopteris cf. reichiana (pl. 1, fig. L), Neuropteris 

rarinervis (pl. 1, ·fig. Q), and Sphenophyllum oblongifolium are sparingly represented. Other species 

in this assemblage are shown on plate 1, figures J, 

K, M, N, 0, and P. Lyons and Darrah (1978) concluded that the assemblage was transitional between 

the Middle and Late Pennsylvanian epochs and is 

similar to that in rocks of the Upper Allegheny and 

Lower Conemaugh. A comparable flora (Lyons, unpub. data) is found at Barrington, R.I. (fig. 9, 

loc. 57). 

Important new collections made in cot:lnection 

with the Narragansett Basin Project are from 

Bristol, R.I. (fig. 9, loc. 92), and the northern part 

of Conanicut Island, Rhode Island. These florules 

have not yet been documented but are probably 

younger than the Easton florule as evidenced by 

the abundance of Odontopteris specimens. Sphenophyllum oblongifolium and several Odontopteris and 

Pecopteris species reported by Lesquereux ( 1889) 

to be present at Pawtucket, R.I. (fig. 9, loc. 10), 

probably are the youngest reported florule from the 

Narragansett Basin. The flora from these three localities and the floras from Newport (fig. 9, loc. 3) 

and Portsmouth, R.I. (fig. 9, loc. 42), and from 

Seekonk, Mass. (fig. 9), are all considered to be of 

Late Pennsylvanian age. 

A florule from Canton, Mass. (fig. 9, loc. 139), 

dominated by N europteris obliqua, Calamites cisti, 
THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES A23 

Cordaites pricipalis, and a few seeds in the upper 

member of the Pond ville Conglomerate in the Norfolk Basin was reported by Lyons Tiffney, and 

Cameron ( 1976). An important discovery in this assemblage was a species probably belonging to Lonchopteris, a genus not known in North America west 

of New England. The authors concluded that the 

assemblage was similar in other respects, however, 

to that in the Upper Pottsville rocks of the Southern 

Anthracite field, Pennsylvania (White, 1900; Wood 

and others, 1969) . 

FLORAL ZONATION 

A sum·mary of the floral zones here recognized in 

the Pennsylvanian rocks of New England is given in 

figure 10. The florule from the Pondville Conglomerate does not readily compare with any floral zones 

of Read and Mamay (1964). However, this florule 

is in the zone of Lonchopteris assigned by J ongmans 

( 1952) to Westphalian B and, therefore, is presumably equivalent to floral zone 5 or 6 of Read and 

Mamay (1964). On the basis of work by Grew, 

Mamay, and Barghoorn (1970), the florule from the 

"coal mine" at Worcester, Mass. (fig. 6), is presumably referable to floral zone 4. However, I have 

identified a probable N europteris scheuchzeri in this 

assemblage and, therefore, refer it to floral zone 9. 

The lower part of the Wamsutta Formation and 

the lower member of the Pondville Conglomerate do 

not have known florules; however, the lower part of 

the Wamsutta is believed to be in floral zones 5 or 

6, and the lower member of the Pondville is believed 

to be in floral zone 5. A florule has not been identified in the Dighton Conglomerate, but, if one is 

identified, it probably will be assignable to floral 

zone 11 or 12 of Read and Mamay ( 1964). 

FAUNA OF THE NARRAGANSETT BASIN 

Summaries of the fauna found in the N arragansett Basin are in Shaler, Woodworth, and Foerste 

(1899), Quinn and Oliver (1962), and Willard and 

Cleaves (1930). 

Scudder .(1893) described an entirely new insect 

fauna from Rhode Island. Although consisting almost entirely of wings, it included a spider, 11 

(nine new) species of cockroaches, and two other 

species of insects. In 1895, he designated one of the 

two cockroaches that were not specifically identified 

in 1893 as a new species and added a new species of 

cockroach from East Providence. The fauna was collected principally at localities near Pawtucket, Silver Spring (East Providence), Cranston, Bristol, 

and East Providence, R.I. ; it was apparently derived from the lower part of the Rhode Island 

TIME-STRATIGRAPHIC UNITS ROCK-STRATIGRAPHIC UNITS 

FLORAL ZONES NEW ENGLAND NEW ENGLAND 

CENTRAL APPALACHIANS 

OF READ AND 

MAMAY (1964) CENTRAL AND EASTERN MASSACHUSETIS FLORAL. FIGURE 9 

NORTH AMERICA EUROPE WESTERN PENNSYLVANIA PENNSYLVANIA WEST VIRGINIA RHODE ISLAND LOCALITY LOCALITY REFERENCE 

NUMBER 

Stephan ian Bl?l or Cl?l 11 or 12 Waynesburg Formation Dighton Congi!JTlerate This report 

Monongahela Formation Pawtucket. AI 10 lesquereux (1889) 

LATE Conemaugh Formation Rhode Island Fom;Jation Portsmouth. R I 42 

PENNSYLVANIAN Stephanian A and B 11 (upper part) (upper part) Darrah (1969) 

Cantabrian Seekonk. MA 14 

Westphalian D 10 Conemaugh Formation Rhode Island Formation 70 lyons and Darrah (lower part) (middle part) Easton. MA (1978) 

late 9 Foxboro. MA 24 lyons (1969) Westphalian C 

Allegheny Formation LLEWELLYN lyons and Chase (upper part) FORMATION Mansfield, MA 16 (1976) 

middle 8 Worcester Grew and others Westphalian C "coal mine", MA (see figure 61 (19701 MIDDLE 

PENNSYLVANIAN Rhode Island Formation Oleksyshyn (19761 early (lower part) Plainville. MA 20 

Westphalian C 7 Allegheny Formation 

(lower part) Valley Falls. R I 1 Round (19201 

late Sharp Mountain Wamsutta Formation Westphalian B (?) 6 or 7 ~------ Member Kanawha Formation (upper part) Attleboro. MA 56 Knox (19441 ;z 

g 

~ 

Westphalian A or B 5 or 6 ::2: Wamsutta Formation 1 This report a: Schuylkill ~ (lower part) 

EARLY Westphalian 

Member ~ Pondville Conglomerate Lyons and others A· > New River Formation Canton. MA PENNSYLVANIAN Namurian C(?l 5(?1 ~ (upper member) (1976) 

Tumbling Run !:2 Pondville Conglomerate 

Member (lower member) 139 This report 

Namurian B 4 Pocahontas Formation 

FIGURE 10.-Pennsylvanian stratigraphic correlation chart. 
A24 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Formation (Shaler and others, 1899, p. 203). Packard (1889) reported that the lower part of the 

Rhode Island Formation in Pawtucket yielded sevez:al other species of cockroaches of two genera ; a 

spider; Spirorbis, a tube of an annelid worm; and a 

presu'med· track of a gastropod. 

Willard and Cleaves (1930) summarized discover-

~es of seven species of amphibian footprints: four 

from Plainville, Mass., and one each from Seekonk', 

(Perrin's Crossing) and South Attleboro, Mass., 

and East Providence, R.I. Six were new species. 

Six were from the Rhode Island Formation, and one 

was from the Wamsutta Formation in South Attleboro. Lyons and Chase (1976) noted possible amphibian skin from Plainville, Mass., and a burrow 

from Foxboro, Mass. 

PALEOGEOGRAPHIC IMPLICATIONS OF 

PALEONTOLOGIC DATA 

Scudder (1895) noted that none of the 193 

species of North American (including Nova Scotia 

and Cape Breton) cockroach was known from 

Europe and that five of the 14 genera found in 

America are absent from Europe. These faunal data. 

may indicate that North America and _western 

Europe were somewhat isolated during Early and 

Middle Pennsylvanian times. However, the presence of Lonchopteris in New England, Maritime 

Canada, and western Europe indicates that North 

America and Europe were connected during these 

times. The absence of Lonchopteris from areas west 

of New England probably indicates a Pennsylvanian barrier between New England and the central Appalachians. 

Willard and Cleaves (1930) observed that the 

amphibian footprints of the Narragansett Basin 

have a closer affinity to the genera identified in 

Nova Scotia than to the genera described for the 

central Appalachians. This affinity to Nova Scotian 

amphibian genera, together with floral data presented by Round (1924) and Lyons (1971), strongly 

supports a paleogeographic connection between New 

England and Maritime Canada (Lyons, 1976) during Middle Pennsylvanian time. 

ROCKS OF MAINE INFERRED TO BE 

CARBONIFEROUS 

By ROBERT G. DOYLE 

Some sedimentary rocks in parts of Hancock and 

Washington Counties, Maine, are inferred to be of 

Carboniferous age. These rocks are not fossiliferous; 

the assignment of this age is based upon (1) 

proximity to similar rocks that are known to be 

Carboniferous and that crop out approximately 56 

km to the east in the Province of New Brunswii!k 

(Larrabee, 1963) ; (2) lithologic character and the 

lack of any metamorphic imprint, the latter requiring a post-Acadian age; and (3) identification of a 

syntectonic granitic source for the conglomeratic 

granite pebbles within the unit. 

LOCATION AND GEOLOGIC SETTING 

The rocks inferred to be of Carboniferous age are 

present in a graben bounded by subparallel segments (fig. 11) of the Norumbega fault system. The 69" 

FIGURE 11.-Locations of Maine rocks inferred to be 

Carboniferous. 

Norumbega fault system is a major structure extending 320 km north-northeast from Portland, 

Maine, on the south-central Atlantic coast to the 

Maine-New Brunswick line 16 km south of Danforth, Maine. Exposures of the unit are present on 

the northwest shore of Great Pond and in Alligator 

Stream which flows into Great Pond (Great Pond, 

Maine, U.S. Geological Survey 15-minute quadrangle). The unit is bounded on the southeast by silicic 

metavolcanic and metavolcaniclastic rocks of pre-
MASSACHUSETTS, RHODE ISLAND, AND MAINE A25 

sumed Ordovician age (Larrabee and others, 1965), 

and on the north by the quartzite member of the 

Kellyland Formation of Silurian age (Larrabee 

and others, 1965; Ludman, 1975). Metasedimentary 

and plutonic rocks of Siluro-Devonian age (Hussey 

and others, 1967) are present in the area near the 

fault-bounded blocks of the unit inferred to be Carboni1'erous. 

DESCRIPTION OF THE UNIT INFERRED TO BE 

CARBONIFEROUS 

Rocks of the unit inferred to be Carboniferous 

were described by Larrabee, Spencer, and Swift 

(1965) and Stoeser (1966). The present writer uses 

the description provided by Stoeser. The unit is 

separated into two members, the siltstone arkose 

member and the nonarkosic conglomerate member. 

Nonarkosic conglomerate member.-The nonarkosic conglomerate member consists of a red silt/ 

sand matrix enclosing clasts of green and red micaceous quartzite, siltstone, and shale and a small percentage of weathered granitic clasts. The source of 

the clasts is the siltstone arkose member. The nonarkosic conglomerate member is estimated to be 30 

m thick. 

Siltstone arkose member.-The siltstone arkose 

member consists of reddish-brown to purple interbedded arkosic conglomerate, arkosic sandstone, and 

red siltstone. The source of clasts found in this 

member is presumed to be nearby Acadian or Late 

Acadian orogenic plutons of mid-Devonian age. This 

member is estimated to be·520 m thick. 

Bconomic deposits.-No evidence exists of any 

economic materials within the unit. Carbonaceous 

material is absent. 

EVOLUTION OF CARBONIFEROUS TERRANES IN 

NEW ENGLAND 

By JAMES W. SKEHAN, S.J., and DANIEL P. MURRAY 

PALEOENVIRONMENT AND PALEOGEOGRAPHY 

The generally similar ages, lithologies, stratigraphy, and structure of the deposits in the Narragansett and Norfolk Basins and of the deposits at 

and near Worcester (fig. 1) suggest that their 

origins are related and that they may have been 

laid down in a' single basin (Quinn and Oliver, 1962). 

Large-scale faulting, deep erosion, and limited studies of the sediments over the. Avalonian terrane in 

which these basins are situated permit only a general reconstruction of the paleoenvironment and 

paleogeography. 

The ages of the Boston, Woonsocket, and North 

Scituate Basins are uncertain. All three basins have 

geologic features similar to those of the Pennsylvanian basins and are close enough to them to have 

been correlated with them. On the other hand, striking dissimilarities in lithology and stratigraphy 

exist between these three basins and the fossiliferous Pennsylvanian basins. For example, C. A. Kaye 

(oral commun., 1977) has noted that the Cambridge 

Argillite of the Boston Basin may be the equivalent 

of the Middle Cambrian trilobite-bearing Braintree 

Argillite~ Moreover, structures in the Roxbury Conglomerate that were previously assumed to be plant 

fossils have been shown to be sandstone pipes 

(Bailey and Newman, 1978). The recent discovery 

of Middle Cambrian trilobites (Skehan, Murray, 

Palmer, and Smith, 1977) in southern Narragansett 

Bay in rocks previously mapped as Carboniferous 

underscores the plausibilty of Kaye's suggestion. 

The fossiliferous Cambrian rocks in the southern 

Narragansett Bay were considered by Dale (1884) 

to be a southern marine facies of an otherwise 

fluvial basin. The Pennsylvanian deposits of the 

Norfolk and Narragansett Basins are thought to 

have been deposited in an upper fluvial environment 

because (1) the Narragansett and Norfolk Basins 

do not contain any marine fossils, (2) the Narragansett Basin coal has extraordinarily low sulfur 

and trace-element contents (Jack Medlin, unpub. 

data, 1977), and (3) coarse conglomerates are widespread throughout several parts of the Pennsylvanian section in both basins. 

The deposits of the Narragansett and Norfolk 

Basins, moreover, contain a great variety of sedimentary structures, including graded bedding, 

crossbedding, scour and fill, mud cracks, loadcasts, 

raindrop impressions (Chute, 1940; Quinn and 

Oliver, 1962; Stanley, 1968), and sandstone dikes 

(Lyons, 1969). These features, together with the 

paleontological evidence, indicate that the known 

Pennsylvanian rocks were deposited in a fluvial nonmarine environment and were exposed to air (Lyons 

and others, 1976, p. 193-194). Thus, we envision, 

for that part of the Carboniferous represented by 

the known Pennsylvanian deposits and by the deposits considered to be possibly Carboniferous, a 

region of high relief following the late Acadian episodes in which previously formed nappe structures 

in central New England (west of this Carboniferous 

terrane) were domed. 

STRUCTURAL EVOLUTION OF 

THE NARRAGANSETT BASIN 

The following sequence, from oldest to youngest, 

of structural events represents a working model for 
A26 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

the deformational history of the Narragansett 

Basin. 

In Rhode Island: 

1. Northeast-trending isoclinal overturned to recumbent folds formed with associated eastdipping to subhorizontal cleavage and northwest-directed thrust faults. 

2. A milder episode of folding was associated with 

northwest-dipping cleavage and southeastdirected northwest-dipping thrusts. 

3. Cleavage was gently warped, and kink bands 

formed. 

In Massachusetts: 

1. Open folds trending east-northeast and having 

northwest-dipping cleavage formed in most of 

the Massachusetts part of the basin. 

2. Possible southeast-directed thrusting may have 

emplaced the Blake Hill thrust sheet in Plainville and possibly other thrust sheets not yet 

well defined. This episode may have been contemporaneous with event 2 (listed above) of 

Rhode Island. 

Several episodes of normal faulting took place 

following these compressional phases of deformation. Faults formed include: 

1. Northwest-striking faults, such as the Portsmouth Abbey fault (William R. Barton, oral 

commun., 1975), that had significant leftlateral strike motion ; such faults are detected 

by drilling (Skehan and others, 1976). 

2. Northeast- and northwest-striking faults. 

3. North-striking faults. 

STRUCTURAL EVOLUTION OF 

SOUTHEASTERN NEW ENGLAND 

In southeastern New England, the basins known 

or thought to be Carboniferous have been deformed 

by folds and faults that are north trending in the 

south and are east-northeast trending in the north. 

This post-Conemaugh (post-Stephanian A) deformation was characterized by northwest-dipping southeast-moving thrusts and highangle reverse faults 

over most of the Avalonian platform. The southern 

part of the platform is dominantly characterized 

by southeast-dipping, northwest-directed thrusts 

that are cut by later northwest-dipping, southeastdirected thrusts. 

TIMING AND CAUSES OF THE 

ALLEGH\ANIAN OROGENY 

A complex structural history is recorded in the 

pre-Carboniferous and Carboniferous rocks of the 

Avalonian terrane of New England. The following 

two-stage working hypothesis is presented to explain the known data. 

1. The Acadian orogeny represents the collision of 

the Eur-Asian and North American plates; the 

Avalonian terrane formed the leading edge .of 

of the Eur-Asian plate and was sutured to 

the North American plate approximately along 

the zone between the Clinton-Newbury and 

the Bloody Bluff fault zones. (fig. 1). This 

suturing defines the final closure of the ProtoAtlantic Ocean (Iapetus). 

2. Closure of the Hercynian Ocean began in late 

Paleozoic times and resulted in the collision 

of Gondwana with Laurasia. This event is recorded as the Alleghanian orogeny in eastern 

North America and the Variscan-Hercynian 

orogeny in northwest Europe. 

Whether the Avalonian plate was overridden by 

the North American plate or vice versa, the ClintonNewbury and Bloody Bluff fault zones (fig. 1) may 

define the suture and mark the northwestern and 

southeastern boundaries of underplating. Thus, the 

faults on these plates initially form·ed during the 

Acadian; however, their present geometry (such 

as the east-directed, west-dipping, high-angle reverse faults in the northern part of the Avalonian 

platform) was defined during the Alleghanian 

orogeny. Here the Alleghanian (Variscan) orogeny 

was a major orogenic event consisting of the following elements: (1) isoclinal folding and refolding associated with thrusting; (2) upper amphibolite 

facies Barrovian regional metamorphism; and (3) 

intrusion of probably anatectic granites. 

The Alleghanian orogeny may either represent: 

( 1) subsequent interactions between the Eur-Asian 

and North American plates or (2) the collision 

of the South American parts of Gondwana with 

Laurasia. The latter interpretation is a logical extension of Irving's ( 1977) data. 

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A28 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

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MASSACHUSETTS, RHODE ISLAND, AND MAINE A29 

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124, 176 p. 

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A30 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

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and Bucknam, R. C., 1965, Implications of new radiometric ages in eastern Connecticut and Massa.chusetts : 

U.S. Geol. Survey Prof. Paper 525-D, p. D1-D10. 
PLATE 1 

A contact photograph of the plate in this report is aV'ailable, at cost, from U.S. 

Geological Survey Library, Federal Center, Denver, Colorado 80225 
PLATE 1 

[All specimens are from Easton, 1\:lass. E number is original specill)en number; HU number is 

Harvard University, Paleobotanical Collections, specimen number. Line scale equals 1 em.] 

Figure A. 

B. 

c. 

D. 

E. 

F. 

G. 

H. 

I. 

J. 

K. 

L. 

Pecopteris arborescens Schlotheim, E-232a, H.U -45708. 

Pecopteris sp., E-116, HU -45709. 

Pecopteris unita Brongniart, E-216, HU -45710. 

Pecopteris aff. hemitelioides Brongniart, E-97, HU-45711. 

Pecopteris arborescens Schlotheim, E-120, HU-45712. 

Pecopteris lamuriana. Heer, E-110, HU-45713. 

Pecopteris aff. hemitelioides Brongniart, E-113, HU-45714. 

PecopteriS cf. lamuriana Heer, E-141, HU-45715. 

Pecopteris· lepido'rachis( ?) Brongniart, E-132, HU-45716. 

Eremopteris cf. lincolniana D. White, E-202a, HU-45717. 

Alethopteris (?) sp., E-195a, HU -45718. 

Odontopteris cf. reichiana Gutbier, E-194, HU-45719, pinnules outlined for 

clarity. 

M. Alethopteris ( ?) (Brongniart) Goeppert, E-143, HU-45720, pinna and 

N. 

0. 

P. 

Q. 

medial veins outlined for clarity. 

Neuropteris obliqua.( ?) Brongniart, E-243a, HU-45721. 

Eremopteris missouriensis "Lesquereux, E-74, HU-45722. ···· 

Sphenopteris aff. subalata Geinitz, E-204, HU-45723. 

Neuropteris rarinervis Bunbury, E-47, HU-45724. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 11!()-A PLATE 1 

N l_j 

PECOPTERIS, EREMOPTERIS, ALETHOPTERIS(?), ODONTOPTERIS, NEUROPTERIS, AND SPHENOPTERIS 
The Mississippian and Pennsylvanian 

(Carboniferous) Systems in the United ·StatesPennsylvania and Ne~ York 

By WilliAM E. EDMUNDS, THOMAS M. BERG, WilliAM D. SEVON, 

ROBERT C. PIOTROWSKI, LOUIS HEYMAN, and LAWRENCE V. RICKARD 

GEOLOGICAL SURVEY 

Prepared in cooperation with the 

Pennsylvania Geological Survey 

and the New York State MuseumGeological Survey 

Historical review and summary of areal} 

stratigraphic} structural} and economic 

geology of Mississippian and 

Pennsylvanian rocks in Pennsylvania 

and southwestern New York 

PROFESSIONAL PAPER 1110-B 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1979 

FIGURE 1. 

2. 

3. 

4. 

6. 

6. 

7. 

8. 

9. 

10. 

11. 

12. 

CONTENTS 

Abstract 

Introduction -----------------------------------------------------------·------

General geologic setting ------------------------------------------------------

The Appalachian geosyncline --------------------------------------------

Climate ------------------------------------------------------------------

Lithostratigraphy ----------------~-------------------------------------------

General --------------------~--------------------------------------------- Riceville-Oswayo through "Hempfield" sequence --------------------------

Rockwell, Huntley Mountain, and Spechty Kopf Formations --------------

Pocono, Burgoon, and Spechty Kopf Formations --------------------------

Loyalhanna and Greenbrier Formations ----------------------------------

Mauch Chunk F~rmation ------------------------------------------------ Major disconformities in the Mississippian and Pennsylvanian Systems --

Pottsville Group ---------------------------------------------------------

Llewellyn Formation ----------------------------------------------------

Allegheny, Conemaugh, and Monongahela Groups --------------------------

Biostratigraphy --------------------------------------------------------------

Paleozoology -------------------------------------------------------------

Paleobotany -------------------------------------------------------------

Chronostratigraphy ----------------------------------------------------------

Depositional history ---------------------------------------------------------

Economic geology ------------------------------------------------------------

Coal ------------------------------------------~-------------------------­ Oil and gas -------------------------------------------------------------- Clay and shale ---------------------------------------------------------- Carboniferous rocks of New York State, by Lawrence V. Rickard ------------

References cited --------------------------------------------------------------

ILLUSTRATIONS 

Page 

81 

1 

4 

4 

4 

4 

4 

6 

9 

12 

12 

12 

13 

14 

14 

14 

15 

15 

17 

19 

19 

23 

23 

25 

29 

30 

31 

Paie 

Map showing outcrop of Mississippian and Pennsylvanian rocks in Pennsylvania and New York -------- 82 

Map showing generalized paleogeography of the Mississippian-Pennsylvanian depositional basin and source 

areas --------------------------------------------------------------------------------------------- 3 

Chart showing primary lithostratigraphic subdivisions of .the Paleozoic -------------------------------- 5 

Diagrammatic cross section showing the relation of second-order to first-order middle and late Paleozoic lithologic subdivisions ----------------------------------------------------------------------- 5 

Correlation chart of Mississippian and Pennsylvanian rocks in Pennsylvania and New York ---------- 6 

Chart showing the relation of first-order and second-order Paleozoic lithologic subdivisions to stratigraphic nomenclature -------------------------------------------------.---------------------------- 7 

Generalized stratigraphic cross section of Mississippian and Pennsylvanian rocks from Somerset County, 

Pa., to Cattaraugus County, N.Y --------------------------------------------~---------------------- 8 

Generalized stratigraphic cross section of Mississippian and Pennsylvanian rocks from Lycoming 

County, through Crawford County, Pa ------------------------------------------------------------- 9 

Generalized stratigraphic cross section of Mississippian and Pennsylvanian rocks from Bedford County 

through Washington County, Pa ----------------------------------------------------------------- 10 

Generalized stratigraphic cross section of Mississippian and Pennsylvanian rocks from Schuylkill County 

to Susquehanna ·County, Pa -------------------------------------------------------.:.--------------- 11 

Chart showing Mississippian and Pennsylvanian floral zones ---------------------------------------- 18 

Maps showing Upper Devonian, Mississippian, and Pennsylvanian paleography and depositional environments -------------------------------------------------------------------------------------------- 21 

III 
IV CONTENTS 

Page 

FIGURE 13. Maps showing Pennsylvanian paleography and depositional environments ---------------------------- 822 

14. Map showing coal fields of Pennsylvania ·-------------------------------------------------------------- 24 

15. Isocarb map of Pennsylvania ------------------------------------------------------------------------- 25 

16. Chart showing Pennsylvania coal-seam nomenclature -------------------------------------------------- 29 

17. Generalized columnar section showing stratigraphic position of oil- and gas-bearing sands in Mississippian and Pennsylvanian rocks of western Pennsylvania ------------------------------------------ 30 

TABLES 

Pue 

TABLE 1. Pennsylvania coal production, 1976 --------------------------------------------------------------------- ~6 2. Recoverable coal resources of Pennsylvania in beds more than 61, 71, and 91 em thick, by counties and 

rank, as of January 1, 1970 ------------------------------------------------------------------------- 27 
THE MISSISSIPPIAN AND PENNSYLVANIAN (CARBONIFEROUS) SYSTEMS 

IN THE UNITED STATES- PENNSYLVANIA AND NEW YORK 

By WILLIAM E. EoMUNDs,1 THOMAS ?yl. BERG,2 WILLIAM D. SEvoN,2 

RoBERT C. PIOTROWSKI,8 Loms HEYMAN,8 and LAWRENCE V. RICKARD4 

ABSTRACT 

The Mississi,ppian and Pennsylvanian rocks of Pennsylvania and New York constitute a dominantly clastic sequence 700 to 3,200 m (2,300 to 10,600 ft) thick. Deposited 

during the late stages of formation of the Appalachian 

geosyncline, most Mississippian and Pennsylvanian sediments issued from the Acadian orogenic highlands to the 

southeast along the presumed impact zone of the North 

American and African continental p.lates. Less sediment 

came from the rim of the North American craton to the 

north and the older Taconic orogenic highlands to the northeast. Paleomagnetic studies suggest that the PennsylvaniaNew York area was slightly south of the equator during 

Mississippian and Pennsylvanian time; examination of the 

fossil flora indicates a mostly subtropical climate. 

Of the seven alternating clastic and carbonate sequences 

that make up the App·alachian Paleozoic, the MississippianPennsylvanian includes parts of the last two clastic sequences and a thin representative of the last intervening 

carbonate sequence. These three primary Paleozoic units may 

be divided into eight major lithologic groupings, which are 

described herein under 16 principal formations or groups. 

Two widespread disconformities exist from upper middle 

Mississippian through lower Middle Pennsylvanian across 

New York and northern Pennsylvania and possibly beyond. 

Biostratigraphic zonation of the Carboniferous of Pennsylvania and New York has not been accomplished yet. The marine Mississippian strata of northwestern Pennsylvania have 

an abundant fossil invertebrate suite, but most research has 

been directed toward locating the Devonian-Mississippian 

boundary. Various avenues of paleozoological research are 

yet to be followed in both the Mississippian and Pennsylvanian, in order to establish true biozones and correlations 

with the midcontinent. 

The Mississippian has been divided into three and the 

Pennsylvanian into nine presumably time-sequential botanical biostratigraphic zones. 

The Devonian-Mississippian. boundary within .the marine 

section of northwestern Pennsylvania is fairly well located; 

the Mississippian-Pennsylvanian boundary is accurately 

located where disconformable. Elsewhere, these two boundaries are only approximate. The Pennsylvanian-Permian 

1 Consulting Geologist, Camp Hlll, Pa. 17011. 

c Pcnnsylvnnllt Geological Survey, Hnrrlsburg, Pa. 17120. 

• PcnnsylvnnhL Oeologlcul Survey, Pittsburgh, Pa. 15222. 

'New York State 1\Iuseum-Oeologlcal Survey, Albany, N.Y. 12224. 

boundary is controversial. Epoch boundaries, except the Desmoinesian and, locally, the Missourian, are indistinct. 

The depositional history of the Mississippian-Pennsylvanian consisted of the following events in chronological 

order: ( 1) Late Devonian and Early Mississippian marine 

transgression; (2) Early Mississippian stable, delta-dominated coast; (3) early middle Mississippian formation of 

elongate braided alluvial-deltaic sand plain; ( 4) late middle 

Mississippian initiation of Mauch Chunk delta in southeast 

Pennsylvania and epeirogenic uplift of northern Pennsylvania and New York; a shallow marine invasion from the 

southwest was interposed between the delta and upwarped 

area; ( 6) Late Mississippian and Early Pennsylvanian 

prograding of Mauch Chunk delta and continued erosion in 

northern Pennsylvania and New York; (6) Early Pennsylvanian alluvial plain established across all of Pennsylvania; 

(7) Middle Pennsylvanian marine influence in western Pennsylvania established shallow-marine-delta-plain-alluvialplain conditions from west to east; (8) Middle Pennsylvanian westward prograding of depositional environment, limiting Pennsylvania to nonmarine deltaic and alluvial conditions; (9) middle Late Pennsylvanian marine incursions 

into Pennsylvania; ( 10) reduction of depositional environment to shallow estuary remote from marine conditions 

,during Late Pennsylvanian; ( 11) Late Pennsylvanian-

'Permian coastal-plain lacustrine environment, apparently 

severed from marine connection. 

In Pennsylvania, recoverable coal resources more than 

61 em thick amount to approximately 30 billion metric tons. 

Coal heat value ranges from 8,200 to 8,800 calories per gram 

(14,700 to 16,800 Btu per pound) on a dry, ash-free basis. 

Pennsylvania coal production in 1976 was 85.6 million 

metric tons. 

Oil and gas production from Mississippian and Pennsylvanian rocks is small. Raw materials for a wide variety of 

ceramic products are available from Pennsylvanian and some 

Mississippian units. 

INTRODUCTION 

The Carboniferous of Pennsylvania and New 

York is an overwhelmingly clastic sequence containing subordinate amounts of limestone and coal. 

Strata of Mississippian and Pennsylvanian age underlie approximately 45 percent of Pennsylvania 

but extend into New York only as small outliers 

aggregating a few square kilometers (fig. 1). Where 

Bl 
82 PENNSYLVANIA AND NEW YORK 

~PERMIAN 

~.ROCKS 

EXPLANAtiON 

~PENNSYLVANIAN 

~ 

r-:·::::f::~:1 MISSISSIPPIAN 

ROCKS ;:·::::=:·::·~:~; ROCKS D ROCKS OLDER THAN 

MISSISSIPPIAN 

7ff 

SfiA~I--- BROAD TOP 

0 I I 

50 

I 

I 

BASIN 

Gettysburg 

0 

100 MilES 

I 

I 

50 1 00 KilOMETERS 

FIGURE 1.-0utcrop of Mississippian and Pennsylvanian 

rocks in Pennsylvania and New York. 

uninterrupted by unconformities, the Mississippian 

and Pennsylvanian together constitute about 25 percent of the total Paleozoic. 

The demonstrable thickness of combined Mississippian and Pennsylvanian rocks ranges from about 

700 m (2,300 ft) in southwestern Pennsylvania to 

3,000-3,200 m (10,000-10,500 ft) at the Schuylkill 

River Gap in. the Southern Anthracite field. Both a 

smaller minimum and larger maximum can be inferred in other areas but cannot be demonstrated 

directly, as the section is incomplete. As an example, 

in the area around Olean, N.Y., basal Pennsylvanian 

rocks rest disconformably upon the uppermost 

Devonian; a reconstructed Pennsylvanian probably 

would not exceed 450 m (1,500 ft). 

The Mississippian and Pennsylvanian sequence 

contains two widespread resistant sandstone intervals which are prominent ridge and scarp formers 

across much of Pennsylvania. The lower of these two 

intervals is the Mississippian Pocono-Burgoon sandstone and conglomerate; the higher is the sandstone 

and conglomerate of the Pennsylvanian Pottsville 

Formation. Individually or jointly, the BurgoonPocono and the Pottsville sustain the high ridges 

surrounding the four anthacite basins and the Broad 

Top and Wellersburg basins. They also form the lip 

of the Allegheny Front escarpment and the cores of 

Laurel Hill, Chestnut Ridge, and Negro Mountain. 

Mississippian and Lower Pennsylvanian rocks are 

best exposed along the Allegheny Front ; around the 

Wellersburg, Broad Top, and the four anthracite 

basins; along the West Branch of the Susquehanna 
THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 83 

River and the upper reaches of the Allegheny River 

and their tributaries; and on the flanks of Laurel 

Hill and Chestnut Ridge. The Middle and Upper 

Pennsylvanian sequence is fairly well exposed along 

the Monongahela, Allegheny, and Ohio Rivers and 

their major tributaries; the headwaters of the West 

Branch of the Susquehanna River; and in many 

major excavations in the Pittsburgh metropolitan 

area. Many good exposures of various parts of the 

section are found along the major Interstate Highways such as I-70, I-76 (Pennsylvania Turnpike), 

100 100 200 KILOMETERS 

100 100 MILES 

u~c~ c:,O 

c~~-1\ o~'c 

I-79,. I-80, and I-81. Excellent exposures of the Mississippian occur in the Lehigh River gorge near Jim 

Thorpe, and excellent exposures of both Mississippian and Pennsylvanian strata are to be found in the 

vicinity of Pottsville. 

The stratigraphic nomenclature used in this 

paper has not been reviewed by the Geologic Names 

Committee of the U.S. Geological Survey. The nomenclature used here conforms with the current 

usage of the Pennsylvania Geological Survey· and 

the New York State Museum-Geological Survey. 

FIGURE 2.-Generalized paleogeography of the MississippianPennsylvanian depositional basin and source areas. 
84 PENNSYLVANIA AND NEW YORK 

GENERAL GEOLOGIC SETTING 

THf: APPALACHIAN GEOSYNCLINE 

Mississippian and Pennsylvanian rocks were deposited during the late stages of formation of the 

Appalachian geosyncline. Dietz (1972) postulated 

that the Appalachian geosyncline formed along the 

eastern edge of the North American continental 

plate when this plate initially separated from the 

northwest African plate during the late Precambrian, thus opening the proto-Atlantic epicontinental 

seaway. 

During the Ordovician Period, the North American and African plates began to close again, crumpling the outer edge of the Appalachian geosyncline. 

By Mississippian time, the two plates were virtually 

in contact (Hurley, 1968; Schopf, 1975, p. 26), and 

large volumes of sediment were being carried westward from the orogenic mountains upthrust along 

the continental margin toward the cratonic core of 

North America (fig. 2). 

These sediments along with a smaller volume issuing 

from the craton formed the Appalachian exogeosyncline of Kay (1951, p. 17 and pl. 5) and the continental-shelf deposits. 

From Silurian time onward, the geosyncline apparently was sealed off at the northern end in 

eastern New York where the Taconic orogenic mountains were driven against the Adirondack cratonic 

high. The eastern orogenic source extended southwestward from the Taconic uplift area through the 

present location of Philadelphia and Baltimore and 

beyond. 

Mountain building associated with the impact 

of the two continental plates was intermittent. 

After the Late Ordovician Taconic culmination, 

the Acadian orogeny, during Middle to Late Devonian time, produced the sediments of the Upper 

Devonian Catskill delta. Effects of Acadian mountain building continued, but with diminishing intensity, into the middle Mississippian. 

A third orogeny produced the Mauch Chunk delta 

during middle to Late Mississippian and culminated 

in the Early Pennsylvanian, when the Pottsville 

sandstone and conglomerate spread westward. Approximately contemporaneously with this cOlntinental-margin orogeny, epeirogenic upwarping along 

the craton margin uplifted central and western New 

York and northern Pennsylvania to the point at 

which further deposition ceased and some erosion of 

Lower Mississippian units took place. 

Continued collision of the continental margins in 

the late part of the Permian Period-the Appalachian Revolution-produced the massive folding that terminated formation of the classic Appalachian geosyncline. Triassic sediments were deposited in the narrow fault-block basins formed during separation of the North American and African 

plates. 

It should be noted that many workers believe that 

Appalachian geosynclinal development and deformation resulted from causes other than the movement 

of co•ntinental plates described above. 

CLIMATE 

Paleomagnetic studies of rocks of Mississippian 

and Pennsylvanian age (Turner and Tar ling, 1975), 

suggest that Pennsylvania and New York lay 

slightly south of the equator at that time (fig. 2). 

Examination of the Mississippian-Pennsylvanian 

flora by White (1913) and by Koppen and Wegener 

(1924) indicated a subtropical setting, although 

probably not as intensely hot as a low-elevation 

equatorial setting today would imply. Camp (1956) 

concluded that Pennsylvania and New York lay near 

the equator in an area that generally received 

abundant year-round rainfall. 

White (1913, p. 74) considered the Mississippian 

flora to be rather impoverished and stunted, a fact 

suggesting that climatic conditions were less than 

ideal. He further noted that the striking evolution 

of new plant forms in the Early Pennsylvanian suggests optimum temperature and rainfall conditions. 

White believed that Middle Pennsylvanian vegetation was somewhat less lush and that a drier period 

prevailed during late Middle and early Late Pennsylvanian. Latest Pennsylvanian floras reflect a return 

to a substantially better climate. 

LITHOSTRATIGRAPHY 

GENERAL 

The most basic or first-order subdivisions of the 

Paleozoic sedimentary rocks of the Appalachian 

geosyncline are the seven alternating clastic and 

carbonate sequences shown in figure 3. The Mississippian and Pennsylvanian of Pennsylvania span 

part of the upper two clastic divisions (DevonianMississippian and Mississippian-Permian) and include a thin representative of the intervening Mississippian carbonate rocks. These first-order stratigraphic units can be further divided into major 

second-order lithologic groupings as shown in figure 4. 

The Devonian-Mississippian second-order units of 

figure 4 are derived conceptually from the "magnafacies" of Caster (1934). The "marine black shale" 

is, in essence, Caster's Cleveland Magnafacies. The 
THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 85 

PERIOD PRIMARY LITHOSTRATIGRAPHIC OROGENY SUBDIV1SIONS OF THE PALEOZOIC 

Appalachian 

Permian 

Mississippian-Permian 

Pennsylvanian 

clastic deposits 

K Mississippian carboflat_e deposits =:;:: 

Unnamed* 

Mississippian 

Devonian-Mississippian 

Devonian 

clastic deposits Acadian 

Silurian-Devonian 

Silurian 

carbonate deposits 

Ordovician-Silurian 

Ordovician 

clastic deposits 

Taconic 

Cambrian-Ordovician 

carbonate deposits 

Cambrian 

Precambrian-Cambrian 

clastic deposits 

*Contemporary with Ouachitaian 

FIGURE 3.-Primary lithostratigraphic subdivisions of the 

Paleozoic. 

"marine fine-grained clastic rocks" and "marine 

mixed clastic rocks" of figure 4 are equivalent to 

Caster's Chagrin and Big Bend Magnafacies. The 

"red, nonmarine mixed clastic rocks" are Caster's 

Catskill Magnafacies. The "nonred, nonmarine mixed 

clastic rocks" of figure 4 are equivalent, to the best 

of our understanding, to Caster's Tioga Magnafacies. 

The "light gray, nonmarine sandstone and conglomerate" is in essence, Caster's Pocono Magnafacies. 

WEST 

OHIO PENNSYLVANIA 

. PERMIAN . . . . . . . ·? . . . . . 

The present lithostratigraphic nomenclature has 

evolved slowly through the efforts of scores of 

workers during the past 140 years. The formal 

terminology used in this report (fig. 5) is that used 

in the 1979 edition of the Geologic Map of Pennsylvania (Berg and others, 1979). The roots of most 

groups and formations shown in figure 5 (if not 

their precise definition and name) were established 

during the 19th and early 20th centuries. Only the 

Huntley Mountain, Spechty Kopf, Casselman, and 

Glenshaw Formations are conceptually of recent 

origin. 

All units are strictly lithostratigraphic and are 

not intended to have any inherent biostratigraphic 

or chronostratigraphic connotation. The relationship 

between the formal stratigraphic terms given in 

figure 5 and the first- and second-order Paleozoic 

subdivisions given in figures 3 and 4 are summarized 

in figure 6. 

All Mississippian units are defined by their bulk 

lithologic character and are distinguished from contiguous units by fairly distinct lithologic differences. 

Most units reflect more or less discrete depositional 

environments. As can be seen in figure 6, there is a 

high degree of conformity and little overlap between 

Mississippian nomenclature and the second-order 

lithologic subdivisions of the upper Paleozoic of 

Pennsylvania. 

In contrast, most Pennsylvanian units are not defined by any bulk lithologic homogeneity but are 

instead intervals bounded by key beds that are asEAST 

PENNSYLVANIAN 

I NONMARINE MIXED CLASTICS 

WITH SOME COAL 

MARINE AND/OR B ACKISH AND NONMARINE MIXED 

CLASTIC 

ROCKS WITH .L---4-.,....------:-'7 

SOME COAL AND MARINE LIMESTONE I 

I 

MISSISSIPPIAN 

. . . . . . DEVONIAN 

AND FRESHWATER LIMESTONE 

·RED, NONMARINE MIXED 

CLASTIC ROCKS 

? NON-R~D, NONMARIN~ •? • • • • • . . . . . . . . . . . . . ' MIXED CLASTIC ROCKS 

FIGURE 4.-Diagrammatic cross section showing the relation of second-order 

to first-order middle and late Paleozoic lithologic subdivisions. 

.? .. 
86 

I-

(1) 

SOUTHWESTERN 

PENNSYLVANIA 

~ ~ ~ ~ FO~~~~I~N ~ ~ ~ ~ 1------1 u E; ~ WASHINGTON 

:::! ~ FORMATION 

1----+----< ':. ?.;.:~~~Wc~~1 

~ z MONONGAHELA 

~ :;!; FORMATION OR GROUP 

> !Pittsburgh coal) 

f--- CASSEL-

~ CONE- MAN FM. 

~ ~ MAUGH I (A~~~N~s.) ~ GROUP SHAW 

:i ~ fM 

PENNSYLVANIA AND NEW YORK 

(2) 

NORTHWESTERN 

PENNSYLVANIA 

AND 

SOUTHWESTERN 

NEW YORK 

(3) 

NORTH-CENTRAL 

PENNSYLVANIA 

(4) 

SOUTH-CENTRAL 

PENNSYLVANIA 

(BROAD TOP) 

Principal groups, formations. and members 

shown by capital letterSKey beds and other notable subordinate units 

shown by capital and lower case letters in 

parentheses. (includes drillers' 'terms in 

SW Pa.) 

CONEMAUGH 

FORMATION 

151 

SOUTHERN 

AND MIDDLE 

ANTHRACITE 

BASINS 

LLEWEUYN 

FORMATION 

(6) 

NORTHERN 

ANTHRACITE 

BASINS 

LLEWELLYN 

FORMATION 

~ "'~ IUpp~L~~':f~~y coal) ~""Y!AL'l'ILE~IGH~EN~Y~...j.....A""LLE""G"'HE....,N""'v ..,....,~1--:LLEGH~~ ~ ~ ~ FOR~:!~~~~~~~~~OUP IB:a~kv~lre ~~I) FM. OR G~ ~ ~ ~ ~~ORMA~~·~I:::;Bu:.::ck:..;:M::;o:::unl:.::ai:.:,:ncToa::!-l)f---!:.IR:::.:ed~A:,::sh::_:c;:::oa:!!..(l) 

~ ~ POTTSVILlE i; ~ 2: . . SHARP 

- z POTTSVILLE POTlSVILLE M. OR GP. ~ 0 ~ POTTSVILLE MOUNTAIN z POTlSVILLE 

~ FORMATION FORMATION FORMATION )'-. < o.. :::> FORMATION MEMBER ~ 

!;( OR GROUP OR GROUP lrlli;Oiean Cgl) n') rnTl?rr ! - r rr IConnoquenesstn~Ss~ IOieanCgl)(" . IIIII ~ :;:lDr ~a: A ((fi].. !Sharon Cgl ~ I rnnrn \ ~0~ ': 

~-+-=--H['tl,f111 ;"'""[RMITY? [l1_lilj.?hlf--? c '-::: -~ - ? r ~u~;~ , , 'e • !;; I ~ /~ MAUCH ~ 7< ~ l5 '1 Wymps ~ ol. CHUNK ~ f---- · Gap Ls ~ DISCONFORMITY II/ \ FORMATION ~ % \ ~ 

z GREEN-~~ J " > 8 ~ ~ ~BRIAR· (~~~ 4-'~0YALHANNI O~om~~~NtR.) ~ ~ \. ~ ~ :E s k'_/ ~1c. s?sl: '"•~'l,~~j\il _I] ~ ~ ~ nrrr 1 ?~1Sf~Nio?~I1J?i 

z ?~/Sr~NjOf~/7'? MT. 

~ BURGOON lfz ~~ BURGOON z CARBON 

~ SANDSTONE - g ~ ~ :=;::: ~ BURGOON SANDSTONE ~ ~ MEMBER. POCONO \ 

L--J--------1 1/ ~~:;; u \ i(s_ SANDSTONE ~ ~ "HEMPFIELo- SH-:-f (Patton Red Shale) (Patton Red Shale)['?, ..._ ?- FORMATION 

1/ SHENANGO ss.l I '1.. BECKCUYAHOGA HUNTLEY ·i_ VILLE 

l2nd Gas sand) ~-~Wf~~~v,~\ ROCKWEU $ MEMBER I 

1Murrysvtlle1 .. Kna "C 1 1hti.s ~::CC: MOUNTAIN SPECHTY / 

S~) PP g ~ i:i!"' IRtddlesburg SPEC~TY KOPF 

1--+-z-_+? ---?- w RICE- - fjc.d;;RunCgll- -?-f-?-- Shaiei' i-?KOPF -?-1-?- -~7 ~ 

z ct ,_ !Hundred- ("Oswayo" ~ VILLE ~OSWAYO FORMATION FORMATION FORMATION 

ct a ~ loot sand) beds) z SHALE FM. FORMATION 

~ ~ ~ . ~ ~ !Woodcock ?0/SCONFORM/TY?j > !:; ~ ~ Ss.) CATS- CATSKILL OR I l ~ ~ 2 !Nineveh en VENANG KILL Fg:~~~I~N HAMPSHIRE Fg:~A~I~N F~~~~~ILOLN ~ Sand) ~ FM. FM. FORMATION 

FIGURE 5.-Correlation chart of Mississippian and Pennsylvanian rocks in Pennsylvania and New York. 

sumed (sometimes fallaciously) to be both distinctive and widely continuous. Aside from the lower 

Pottsville sandstone and conglomerate, there is no 

dominant lithologic distinctiveness to any substantial 

part of the Pennsylvanian. All is a more or less 

heterogeneous mixture of sandstone, shale, claystone, limestone, and coal. Such differences as do 

exist are subtle variations in proportion, such as a 

change from 4 or 5 percent coal within the Allegheny 

Group to 1 or 2 percent in the Conemaugh Group. 

For this reason, there is a large amount of overlap 

between the nomenclature and the second-order divisions in figure 6. 

on sequence among a multiplicity of overlapping 

local beds and lenses, and on the above-mentioned 

subtle variations in lithologic proportion. Pennsylvanian lithostratigraphic subdivision will not e;;tsily 

stand rigorous application of the standard rules of 

stratigraphic nomenclature. 

Stratigraphic relationships among the Mississippian and Pennsylvanian units given in figure 5 across 

Pennsylvania are shown in the panel diagrams of 

figures 7 through 10. 

RICEVILLE-OSWAYO THROUGH "HEMPFIELD" 

SEQUENCE 

(Figure 5, column 2) Most of the unit-defining key beds are coal, and, 

with one exception, all generally fail to meet the 

strict requirements of widespread continuity and 

distinctiveness expected of a key bed. Boundaries of 

most Pennsylvanian units are projected on interval, 

The Riceville-Oswayo through "Hempfield" sequence in north'Yestern Pennsylvania spans the Devonian-Mississippian boundary and is a mixture of 

fine-grained sandstone, siltstone, and shale, contain-
THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

FIRST-ORDER LITHOLOGIC DIVISIONS OF 

THE APPALACHIAN 

PALEOZOIC (FIGURE 3) 

., 

Mississippian--Permian 

clastic rocks (lower 

part) 

Mississippian carbonate 

rocks 

Devonian-Mississippian 

clastic rocks (upper 

part) 

' 

SECOND-ORDER LITHOLOGIC LITHOSTRATIGRAPHIC DIVISIONS OF THE APPALACHIAN NOMENCLATURE PALEOZOIC IN PENNSYLVANIA (FIGURE 5) : (FIGURE 4) 

Dunkard Group (Permian) 

Monongahela Group or Formation 

Nonmarine mixed clastic deposits Casselman Formation 

with some coal and fresh-water Conemaugh Group (S. central Pa.) 

limestone. Upper Allegheny Group (SW. and NW. Pa.) 

Allegheny Group (N. central and S. central Pa.) 

Upper Pottsville Group (N. central ~nd S. central Pa.) ... 

Marine and/or brackish· and 

Glenshaw Formation (SW. Pa.) nonmarine:mixed clastic 

deposits with some coal Lower Allegheny Group (SW. and NW. Pa.) 

and marine limestone Upper Pottsville Formation or Group (SW .. and NW. Pa.) 

Sandstone and conglomerate Llewellyn Formation 

Lower Pottsville Formation or Group (western and with some coal and finer central Pa. and SW. N.Y.) clastic deposits Pottsville Formation (eastern Pa.) 

Greenbriar Formation 

Limestone to calcareous sandstone Loyalhanna Formation 

Wymps Gap Member of Mauch Chunk Formation 

Red, nonmarine mixed clastic Mauch Chunk Formation deposits (Mississippian) 

Light gray, nonmarine sandstone Burgoon Sandstone 

Pocono Formation and conglomerate Spechty Kopf Formation (in part) 

Non-red, nonmar.ine mixed clastic Rockwell Formation 

Huntley Mountain Formation deposits Spechty.Kopf Formation (in part) 

Unnamed marine equivalents of Burgoon Sandstone 

Marine mixed clastic deposits Riceville-Oswayo through "Hempfield" sequence 

Venango Formation (Devonian) 

Red nonmarine mixed clastic · 

deposits (Devonian) Catskill (Hampshire) Formation (Devonian) 

Marine fine grained clastic deposits Not represented in figure 5 

Marine black shale Not represented in figure 5 

FIGURE 6.-The relation of first-order and second-order 

Paleozoic lithologic subdivisions to stratigraphic nomenclature. 

87 
88 PENNSYLVANIA AND NEW YORK 

:I: 

(!) 

::::> 

~ 

~ 

Somerset Johnstown 

~ ~ 

CASSELMAN. FORMATION 

Ebensburg Coalport Clear&eld 

+ + ~ 

PENNSYLVANIA 

~--------~A-m_e_s_m_a~rin_e_z_o-ne--------------------~~ 

0 GLENSHAW FORMATION 

Driftwood 

t Brookhind 

~ 

Wharton 

u t 

Upper Freeport coal 

ALLEGHENY GROUP 

Note: Pennsylvanian units are 

essentially time parallel 

Principal groups, formations, and 

members shown by capital letters. 

Key beds and other notable subordinate units shown by capital and 

lower case letters. 

MILES 

0 10 20 

I I 

I 

I 

I I 

I 

0 10 20 30 

KILOMETERS 

Approximate vertical 

exaggeration X 170 

300 

200 

500 

400 

100 300 

50 200 

100 

0 0 

>I 1€-----------------------------272 Kilometers (170 miles)--------------------~ 

FIGURE 7.-Generalized stratigraphic cross section Of Mississippian and Pennsylvanian rocks from Somerset County, 

Pa., to Cattaraugus County, N.Y. 

ing occasional zones of flat-pebble conglomerate. 

Sandstones and intervening finer grained units have 

been named individually, but the entire sequence has 

no collective name. As long as individual units persist, this system of individual names works well. 

When, however, a component (usually one of the 

sandstones) disappears laterally, the nomenclature 

breaks down, resulting in the nameless gaps appearing in figure 5, column 2 bottom. The name "Hempfield" for the shale sequence overlying the Shenango 

Sandstone proposed by Caster (1934) is flawed by an 

erroneous type section, based on a miscorrelation in 

which the shale cited actually underlies the Shenango Sandstone rather than overlying it as Caster intended (Kimmel and Schiner, 1970). Kimmel and 

Schiner ( 1970) chose to correct the error by in corporating the shale overlying the Shenango Sandstone into an extended Shenango Formation as an 

unnamed upper member. It would be preferable to 

retain the name "Shenango" for the sandstone alone 

and to formally name the shale above the Shenango 

Sandstone. The informal term "Hempfield" is used 

in this report when the unit in question is discussed. 

Shale and siltstone in this sequence are generally 

dark gray to medium dark gray, weathering to light 

olive gray or olive gray. Some shale is also grayish 

red to grayish brown. Sandstone is medium light 

gray to olive gray and has planar bedding and smallto medium-scale crossbedding. These rocks frequently have an abundant and diverse marine invertebrate fauna, extensive bioturbation, numerous 

trace fossils, some fish remains, and rare plant frag-
THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 89 

MeadviUe TltusviUe 

! l 

. . .. 

VENANGO FORMATION 

Note: Pennsylvanian units are 

essentially time parallel 

KeUettviUe 

t 

LIMIT 

St. Marys 

~ OF OUTCROP 

Renow 

J 

WatervUie 

t 

ovalhanna 

Fm. 

~-----------------256 Kilometers (160 miles)-----------------~ 

0 

I 

0 

5 10 

I I I I 

10 20 

METERS FEET 

20.MILES 

I I 

300 1000 

30 KILOMETERS 

200 

PENNSYLVANIA Principal groups, formations and 

members shown by capital letters. 

500 

400 

300 

200 

100 

0 

Key beds and other subordinate units 

shown by capital and lower case letters. 

100 

50 

VERTICAL EXAGGERATION X210 

0 

FIGURE B.-Generalized stratigraphic cross section of Mississippian and Pennsylvanian rocks from Lycoming County, 

through Crawford County, Pa. 

ments. Where completely present, the Riceville-Oswayo through "Hempfield" is about 180 to 215 m 

(600 to 700 ft) thick. 

The "unnamed marine clastics" which are laterally 

equivalent to the Burgoon Sandstone (fig. 5, column 

2) are also, logically, an. upward continuation of 

Riceville-Oswayo through "Hempfield" sequence. 

Only recently recognized, these post-"Hempfield" 

marine rocks are exposed at the surface in limited 

areas in northern Armstrong and northwest Indiana 

Counties. They probably continue in the subsurface 

westward to Ohio, where a similar relationship is 

noted between the Logan (Burgoon) Sandstone and 

laterally equivalent marine beds. 

The transgressive marine Riceville-Oswayo 

through "Hempfield" sequence that overlies the regressive marine Venango Formation and prograding 

nonmarine Catskill Formation is the facies equivalent of the dominantly nonmarine Huntley Mountain 

and Rockwell Formations. The sub-Burgoon section 

in the subsurface of southwestern Pennsylvania 

(fig. 5, column 1) is essentially a continuation of the 

general Riceville-Oswayo through "Hempfield" marine interval. 

This sequence, along with the unnamed marine 

equivalents of the Burgoon, is approximately correlative with the Waverly Group of Ohio. 

ROCKWELL, HUNTLEY MOUNTAIN, AND 

SPECHTY KOPF FORMATIONS 

(Figure 5, columns 3-6) 

The Rockwell Formation, Huntley Mountain Formation (Berg and Edmunds, 1979), and, in most 

areas, the Spechty Kopf Formation are a dominantly 
BlO PENNSYLVANIA AND NEW YORK. 

Brownsville 

t 

Central City 

+ 

::I: 

(!) 

::>0.. CASSELMAN FORMATION 

1----~ ~~---------~~~~~~------------~ ~ Ames marine zone ZC!) 

0 

u GLENSHAW FORMATION 

Upper Freeport coal 

ALLEGHENY GROUP 

0 

c 

ri 

:::0 

0 

., 

Brookville-Clarion coal co~· lex . Gordon coal r-------..:.:.;:.::.::::..:.:.:;::_-=.:.=.:..:.::::.:..:..~~~.:.r::.:;~;..._--...,_.--:---:--~-~-f-- --? ---t--"""='"="""__, 

POTTSVILLE GROUP M~'=~~'!_~~~a!t!£~£k~ t------.:::=::--------------Connoquenessing Sandstone 

Hundred-foot Sand 

Principal groups, formations and 

members shown by capital letters. 

Key beds and noteable subordinate 

units (including drillers terms) 

shown by capital and lower case letters. 

PENNSYLVANIA 

Note: Pennsylvanian units are 

essentially time parallel 

METERS FEET 

300 1000 

200 

500 

400 

100 

~\ ,, 

,, 

,, 

,, 

\ 

\ 

,, 

,, 

,, 

,, '· \ 

\ 

' \ 

,, 

'\ 

'\\ 

\ 

~ 

., 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

'\ 

ROCKWELL ' 

FORMATION 

VERTICAL 

' ' 

300 EXAGGERATION X175 

MAUCH 

CHUNK 

FM. 

50 0 5 10 20 MILES 

100 I I I I 

0 0 I I i 

0 10 20 30 KILOMETERS 

~---------------192 Kilometers (120 miles)--------------~ 

FIGURE 9.-Generalized stratigraphic cross section of Mississippian and Pennsylvanian rocks from Bedford County, 

throue:h Washington County, Pa. 
THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 811 

Pottsville Hazleton Sugar Notch Mountain Top Pittston Dunmore Forest City 

~ 

LLEWELLYN 

FORMATION 

Buck Mountain coal SHARP MTN. MEMBER 

SCHUYLKILL MEMBER 

TUMBLING RUN MEMBER 

MAUCH 

CHUNK 

FORMATION 

Prinicpal formations and members shown by 

capital letters. 

Key beds and other notable subordinate units 

shown by capital and lower case letters. 

~ ~ i ~ ~ 

800 

2000 

500 

1000 

5 10 20 MILES 

I I I I 500 I I 100 

10 20 30 KILOMETERS o 0 

VERTICAL EXAGGERATION X26 

PENNSYLVANIA 

~------------------131 Kilometers (82 miles)-------------------7> 

FIGURE 10.-Generalized stratigraphic cross section of MisSISSippian and Pennsylvanian rocks from Schuylkill 

County to Susquehanna County, Pa. 

nonmarine mixture of sandstone, siltstone, and 

shale. 

All three units are lateral equivalents of one another and of the lower part of the Pocono Sandstone 

of northeastern Pennsylvania as well. In its type 

area around the western end of the Southern Anthracite field, the Spechty Kopf is· almost entirely 

sandstone and lithologically is a continuation of the 

overlying Pocono. Elsewhere, the Spechty Kopf is 

the nonmarine mixture mentioned above and is generally rather similar to the Rockwell Formation, except for the lack of red beds. 

The Rockwell and Huntley Mountain are dominantly nonmarine facies equivalents of the RicevilleOswayo through "Hempfield" marine sequence of 

northwestern Pennsylvania; they interfinger with 

marine beds along their western margin. A few 

marine units, such as the Cedar Run conglomerate 

bed of the Huntley Mountain and the Riddlesburg 

shale member of the Rockwell represent strong, but 

brief, eastward marine transgressions. 

There is some indication that the Huntley Mountain thickens in north-central Pennsylvania, replacing the Burgoon Sandstone by facies change in much 

the same way that the Burgoon is replaced by marine facies equivalents in northwestern Pennsylvania. In western Maryland, the Rockwell seems to 

replace the Burgoon in a similar way. 

The sandstone, siltstone, and shale of these formations are generally various shades of gray or greenish gray. Plant fossils are sometimes present. The 

Rockwell and Huntley Mountain contain scattered 
812 PENNSYLVANIA AND·NEW YORK 

grayish-red shale and some thin beds or lenses of 

flat pebble conglomerate. The Spechty Kopf and 

Rockwell locally contain notable occurrences of 

diamictite, which may be glacial or glaciofluvial deposits (Sevon 1973). 

The Huntley Mountain is distinguished from the 

Rockwell and Spechty Kopf by its overall greenish 

or olive cast and by much thin flaggy sandstone. 

The Huntley Mountain has more lithic affinity to 

the underlying Catskill Formation, whereas the 

Spechty Kopf and Rockwell appear to have more 

lithic a.ffinity to the overlying Pocono Formation. 

The distinctiveness of the Huntley Mountain Formation is believed to.stem from differences in provenance and basin characteristics. The sediment source 

·for the Spechty Kopf and Rockwell was the "new" 

orogenic belt to the southeast (Pelletier, 1958), 

whereas the Huntley Mountain may have been derived partly from the old Taconic Highlands to the 

northeast and possibly the craton to the north as 

well. In addition, the Huntley Mountain was deposited in the more restricted northeastern end of 

the Appalachian basin. 

The Rockwell, Huntley Mountain, and Spechty 

Kopf Formations are generally 180 to 250 m ( 600 

to 800 ft) thick. Where they apparently replace the 

Burgoon Sandstone laterally, the Huntley Mountain 

and Rockwell may expand to 300m (1,000 ft). 

POCONO, BURGOON, AND SPECHTY KOPF FORMATIONS 

(Figure 5, all columns) 

The Pocono and Burgoon Formations and, in its 

type area around the western end of the Southern 

Anthracite field, the Spechty Kopf Formation are 

dominantly medium- to coarse-grained, mediumlight to very light gray sandstone· often containing 

quartz pebble conglomerate zones. No red beds are 

present, but subordinate dark shale and· siltstone 

are found. The Pocono is as much as 500 m (1,650 

ft) thick and the Burgoon as much as 110 m (360 

ft). Plant fossils are common, especially in the finer 

grained lenses, but no marine invertebrate fossils are 

found. 

The Burgoon appears to be the westward extension of the upper part of the Pocono. Around its 

depositional margins, the Pocono-Burgoon appears 

to grade laterally into upward extensions of subjacent units: the Huntley Mountain Formation in 

north-central Pennsylvania; the lower Mississippian 

marine clastic rocks of northwestern Pennsylvania 

and Ohio; and the Rockwell Formation in western 

Maryland and northern West Virginia. 

LOYALHANNA AND GREENBRIER FORMATIONS 

(Figure 5, columns 1, 3, and 4) 

The Loyalhanna Formation is a thin tongue, less 

than 30 m ( 100 ft) thick, of the middle Mississippian Greenbrier Group limestone extending across 

southwestern and central Pennsylvania. The Loyalhanna grades from a sandy limestone in the south 

to a calcareous sandstone in the north, in most places 

strikingly crossbedded. A second thin Greenbrier 

tongue, the Wymps Gap Limestone Member of the 

Mauch Chunk Formation, is present throughout 

much of southwest-central Pennsylvania. The 

Loyalhanna and Wymps Gap merge in southwestern 

Pennsylvania to form the subsurface Greenbrier 

Formation, which in turn is traceable into part of 

the thick Greenbrier carbonate sequence of West 

Virginia (Adams, 1970). 

The Loyalhanna lies directly and possibly disconformably upon the upper surface of the Burgoon 

Sandstone except in part of north-central Pennsylvania, where an early wedge of the Mauch Chunk 

Formation intervenes (Wells, 1974). 

MAUCH CHUNK FORMATION 

(Figure 5, columns 1, 3-6) 

The Mauch Chunk Formation is composed of grayish-red shale and siltstone and some light-gray to 

yellowish-gray sandstone. It is almost entirely nonmarine, containing some plant fossils and fish fragments. Maximum thickness is uncertain but probably is in the 2,450- to 2,750-m (8,000- to 9,000-ft) 

range. 

The lower part of the Mauch Chunk is a facies 

equivalent of the Greenbrier-Loyalhanna. In southwestern Pennsylvania, the basal Mauch Chunk 

wedges out between the underlying Loyalhanna and 

the Wymps Gap Limestone Member of the Mauch 

Chunk, which converge to form the Greenbrier 

Limestone of southwesternmost Pennsylvania. In 

part of north-central Pennsylvania, a tongue of 

Mauch Chunk red beds underlies the Loyalhanna 

facies. 

The upper Mauch Chunk is also a facies equivalent 

of the basal Pottsville in the area of the Southern 

Anthracite field where the two units are interbedded. 

Whether the Pottsville-Mauch Chunk contact is conformable or disconformable elsewhere has caused 

considerable controversy, which is discussed in the 

following section. 

The Mauch Chunk is absent because of nondeposition or erosion, or both, throughout northwestern 

Pennsylvania and adjacent New York, as well as extreme southwestern and northeastern Pennsylvania. 
THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 813 

It undergoes considerable facies changes from southwest to northeast before it is cut out erosionally 

along the margins of the Northern Anthracite field. 

MAJOR DISCONFORMITIES IN THE MISSISSIPPIAN AND 

PENNSYLVANIAN SYSTEMS 

(Figure 5, columns 1, 4, and 6) 

The formation of two widespread disconformities during the Mississippian and Pennsylvanian 

Periods has been hypothesized for Pennsylvania and 

New York. The earlier of these disconformities is 

believed to have formed on top of the Burgoon Sandstone before deposition of the Loyalhanna Limestone 

during Meramecian and, perhaps, early Chesterian 

time (Reger, 1927). The second disconformity, between the basal Pottsville and the underlying Mississippian and uppermost Devonian strata, formed 

from late Chesterian through early Atokan time. 

The existence of the Burgoon-Loyalhanna disconformity is largely based upon the presumed relative 

ages of the Loyalhanna-Greenbrier (late Meramecian, on the basis of marine invertebrates) and the 

Burgoon (presumed Osagean at the latest, on the 

basis of plant fossils). However, the reality of this 

disconformity is questionable. The contact between 

the two is sharp but otherwise remarkably uniform. 

The age of the Loyalhanna is probably fairly reliable, but control on the terminal age of the Burgoon 

is very weak. We postulate later in this report that 

the Burgoon Sandstone was deposited on a vast 

anastomosing alluvial sand plain, which by Meramecian time was depositionally static. If so, the 

relation between the Burgoon and Loyalhanna is 

simply that of a transgressive marine unit encroaching on a foundering alluvial plain. However, at the 

same time, it appears that epeirogenic uplift was beginning in northern Pennsylvania and New York 

inducing mild erosion of the Lower Mississippian 

sediments and restricting the northwestward encroachment of the Loyalhanna. The northern source 

of the sand fraction of the Loyalhanna is believed 

to be an erosional escarpment of the Burgoon. 

The sub-Pottsville disconformity was originally 

proposed by I. C. White (1891) to explain the absence of certain floral assemblages from the presumed time-sequential Mississippian-Pennsylvanian 

paleobotanical zonation system. The disconformity 

was also proposed to explain the northwestward 

thinning of the Pennsylvanian Pottsville and the 

progressive northwestward loss of the Mississippian 

Mauch Chunk Formation and subjacent Mississippian strata. 

Only in the Southern Anthracite field (fig. 5, 

column 5), and in southeastern West Virginia, 

where the complete floral sequence is present, were 

the Mauch Chunk (or equivalent in West Virginia) 

and Pottsville believed to be conformable. North and 

west from these limited conformable areas, successively older Mississippian strata were believed to 

have been truncated by erosion during Early Pennsylvanian time. After erosion, Pennsylvanian Pottsville units were deposited in onlap fashion, so that 

the basal Pennsylvanian became progressively 

younger to the northwest. In the extreme case in 

New York, the Lower Pennsylvanian Olean conglomerate rests disconformably upon the uppermost 

Devonian Oswayo Formation. 

There seems to be little doubt that in places where 

the Pottsville rests upon units older than the Mauch 

Chunk, a disconformity is required. In at least part 

of northern Pennsylvania and New York, erosion 

probably continued from the Meramecian Epoch 

into the Morrowan or, possibly, the Atokan Epoch. 

To what extent erosion was continuous during this 

span of time depends entirely upon how far north 

Mauch Chunk sediments encroached before being 

eroded back to their present limit. The lower beds 

of the Mauch Chunk (excluding the pre-Loyalhanna 

tongue in north-central Pennsylvania) now extend 

only a short distance beyond the northern limit of 

the Loyalhanna. Around its present margin, the 

Mauch Chunk apears to have been uplifted and 

eroded back by the Late Mississippian to Early 

Pennsylvanian epeirogenic activity, but how far this 

beveling cut the Mauch Chunk back from its original 

maximum encroachment is unknown. Nor is it clear 

how far to the southeast this erosional disconformity continues upon the upper surface of the Mauch 

Chunk. 

According to White's classical concept, the disconformity should exist where the lowest Pennsylvanian floral zone disappears. If this concept is 

true, the disconformity would extend across the 

entire State, except for the Southern Anthracite 

field. However, physical observation of the Mauch 

Chunk-Pottsville contact in other areas has produced 

doubts about any substantial disconformable break 

(Ferm and Cavaroc, 1969; Ferm, 1974). Glass and 

others (1977, p. 14) have suggested that some of the 

Lower Pennsylvanian floral zones are biofacies 

equivalents of the Upper Mississippian zone related 

to the Mauch Chunk Formation. This possibility 

has been rejected by most paleobotanists on the 

basis of phylogenetic comparisons between floral 

suites of the zones involved. It is also possible that 

the interrelationships between the floral assemblages 

and the lithostratigraphic units may have been 

oversimplified, resulting in the misplacing of a 
·B14 PENNSYLVANIA AND NEW YORK 

lithostratigraphic boundary on a biostratigraphic 

basis. 

POTTSVILLE GROUP 

(Figure 5, columns 1-6) 

The Pottsville is dominantly sandstone, conglomerate, and siltstone, and has subordinate amounts of 

coal, shale, and limestone. Thickness of the group 

is 215 to 460 m (800 to 1,500 ft) in the Southern 

and Middle Anthracite fields, but only 15 to 85 m 

(50 to 250 ft) elsewhere in Pennsylvania. 

The Pottsville is entirely nonmarine except in 

western Pennsylvania, where some marine limestone 

and shale are present in the upper part. Plant fossils are common throughout. 

The lower Pottsville is a facies equivalent of the 

uppermost Mauch Chunk in the. area of the Southern 

Anthracite field and may or may not be conformable 

with most of the Mauch Chunk elsewhere (see preceding section on "Major Disconformities"). The 

Pottsville rests disconformably on lower units down 

to the Upper Devonian Oswayo in northwestern 

Pennsylvania and southwestern New York, and the 

Upper Devonian Catskill Formation at the northern 

end of the Northern Anthracite field. 

The Pottsville is thinnest ( 15 to 40 m, 50 to 130 

ft) where it lies directly upon the eroded Burgoon 

Sandstone, which apparently produced an Early 

Pennsylvanian topographic high. The unusual Mercer high-alumina flint clays occur at this disconformable Burgoon-Pottsville contact and at a similar 

contact between the Pottsville and a resistant sandstone in the lowermost part of the Mauch Chunk 

Formation. 

The Pottsville in northwestern and north-central 

Pennsylvania was derived from the reworking of 

earlier Paleozoic sediments in New York uplifted 

around the rim of the North American craton (Fuller, 1955). The source of the remaining Pottsville 

was the orogenic highlands to the southeast (Meckel, 

1967). 

LLEWELLYN FORMATION 

(Figure 5, columns 5 and 6) 

The Llewellyn Formation is a mixture of interbedded conglomerate, sandstone, siltstone, claystone, 

and coal. The Llewellyn is the lateral equivalent of 

the Allegheny and Conemaugh Groups of western 

Pennsylvania, and possibly the Monongahela Group 

and part of the Dunkard Group as well. In general, 

the Llewellyn is much coarser grained than the 

equivalent rocks to the west. Maximum remaining 

thickness is 1,070 m (3,500 ft). The entire sequence 

is nonmarine, except for the thin Mill Creek limestone bed in the Northern Anthracite field (Chow, 

1951). Plant fossils are common. 

ALLEGHENY, CONEMAUGH, AND MONONGAHELA 

GROUPS 

(Figure 5, columns 1-4) 

The Allegheny, Conemaugh, and Monongahela 

Groups are a sequence composed of many beds of 

sandstone, siltstone, claystone, coal, and limestone. 

Except locally, no rock type is dominant throughout 

any substantial part of the section. Subtle differences 

are found in the proportion of the various rock 

types as well as changes in secondary characteristics, such as color and presence or absence of 

marine fossils. 

The establishment of these three groups along 

with the overlying Permian ( ?) Dunkard Group 

arose from early recognition that parts of the 

total post-Pottsville sequence frequently contained 

mineable coal beds, whereas others did not. The 

Allegheny and Monongahela have mineable coals 

and were originally called the "Lower Productive" 

and "Upper Productive," respectively, whereas the 

Conemaugh and Dunkard, which contain thin seams, 

were the "Lower Barren" and "Upper Barren." In 

effect, these units were defined by a slight change in 

a secondary characteristic (thickness) of a volumetrically minor lithologic constituent (coal). 

Whatever its economic virtue, the use of "coal 

mineability" as the defining characteristic for formal 

geologic units was vague and impossible to apply 

consistently. Recognizing this difficulty, and faced 

with a lithologically heterogeneous. section, 19th 

century geologists turned to key beds to provide 

boundary markers for the Allegheny, Conemaugh, 

and Monongahela Groups. To retain the concept that 

the Allegheny and Monongahela Groups contained 

most of the mineable coals, the key beds selected 

were the lowest and highest coal beds in each 

unit. 

Inasmuch as a key bed must be a single identifiable widespread unit, it has been accepted, more· or 

less on faith, that coal seams do indeed have these 

necessary characteristics. In reality, only the Pittsburgh coal (the base of the Monongahela Group) 

has the true continuity expected of a key bed. In 

practice, the other boundaries of the four groups are 

correlated generally on the basis of vertical spacing, 

and by reference to the relative position of a 

multiplicity of other beds recognized throughout the 

sequence. Any coal conveniently close to the expected key-bed boundary is used as such, so long as 

it persists. For obvious reasons, the code of strati-
THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 815 

graphic nomenclature (American Commission on 

Stratigraphic Nomenclature, 1970) cannot be rigously applied to these units; 

The Allegheny Group from the base of the Brookville coal to the top of the Upper Freeport coal is 

persistently about 80 to 100 m (270 to 320 ft) 

thick. The lower half contains some marine or 

brackish water units and no freshwater limestone. 

The upper half is entirely nonmarine and contains 

freshwater limestone. The Allegheny Group has no 

redbeds. 

The Conemaugh Group lies between the top of the 

Upper Freeport coal and the base of the Pittsburgh 

coal; it is divided into two formations at the top 

of the Ames marine zone. The lower formation 

(Glenshaw) contains four widespread marine zones. 

The upper formation (Casselman) is entirely nonmarine except for a limited brackish-water zone in 

the lower part. The Conemaugh Group ranges from 

less than 170 m (550 ft) in Washington County, to 

more than 275 m (900 ft) in Somerset County. It 

contains scattered redbeds and nonmarine limestones throughout; several marine limestone units 

occur in the Glenshaw Formation. 

The Monongahela Group extends from the base 

of the Pittsburgh coal to the top of the Waynesburg 

coal, and is 85-115 m (275-375 ft) thick in Pennsylvania, increasing from west to east. It is entirely 

nonmarine, contains abundant freshwater limestone, 

and has no redbeds. 

BIOSTRATIGRAPHY 

Marine units containing the principal faunal suites 

are largely confined to the Devonian-Mississippian 

Riceville-Oswayo through "Hempfield" sequence; 

the Mississippian Loyalhanna-Greenbrier sequence ; 

and the Pennsylvanian lower Allegheny Group and 

Glenshaw Formation. Marine units are mostly limited to western Pennsylvania. (See figs. 4 and 5.) 

Except for a few thin marine tongues, all the remaining Mississippian and Pennsylvanian is nonmarine, and the associated fauna is sparse and 

poorly understood. 

Fossil plants are common in the Pennsylvanian 

sequence, and the interrelations between the Pennsylvanian flora and fauna are fairly well understood. 

Plant fossils occur sporadically throughout the nonmarine Mississippian sequence but only rarely in 

close association with any marine fauna. 

PALEOZOOLOGY 

In 1948, Cooper (p. 256) commented on the paleontologic aspects of the Mississippian System in the 

central and northern Appalachians: "The stratigraphic work upon which the succession was divided 

into formations was almost entirely of a physical 

character, and it has been carried on in a near-vacuum of systematic paleontology. Thus many regional 

correlations are inaccurate." In 1979, that statement 

regarding the Mississippian of Pennsylvania is still 

valid. A similar but less harsh commentary is applicable to the present status of paleozoologcal research 

in the Pennsylvanian System of this part of the 

Appalachian region. 

Although adequate paleontological studies of the 

Mississippian are lacking, the singularly important 

contributions on this subject by Caster (1930, 

1934) and Chadwick ( 1935) should be recognized. 

Caster's documentation of Late Devonian and 

Mississippian invertebrates of northwestern Pennsylvania, along with his pioneering formulation of 

facies concepts still stands today as the standard 

biostratigraphic reference for that area. 

Because of the complex facies patterns and lateral 

intergradations discussed by Caster (1934) and 

herein under "Lithostratigraphy," and because of 

the necessarily voluminous systematic paleontology 

yet to be accomplished, a biostratigraphic zonation 

of the Lower Mississippian marine sequence has 

not been established. Considerable effort has been 

directed at establishing the position of the Mississippian-Devonian boundary (Caster, 1934; Chadwick, 1935; Holland, 1958), and consideration has 

been given to the possibility that many faunal elements may overlap and approximate a gradation 

(Caster and others, 1935). Caster's invertebrate 

faunal lists (1934) tell little of actual abundances 

of the various taxa, but some inferences can be 

made regarding diversity changes from Devonian 

to Mississippian. In the Mississippian, there appear 

to be significant diversity increases amongst strophomenid and spiriferid brachiopods, along with increases of diversity amongst archaeogastropods, 

particularly the trochinids. 

Holland (1958) described 47 species, subspecies, 

and morphological variants of brachiopods in the 

Oswayo and Knapp Formations. He concluded that 

only two species crossed the Oswayo-Knapp 

boundary (1958, p. 71) in the Bradford-Warren 

area. The systemic boundary is there placed at the 

horizon having the greatest number of new brachiopod forms. Chief among these brachiopods are the 

genera Dictyoclostus and Syringothyris. Holland 

(1958, p. 71) admitted that facies may be a 

controlling factor in the distribution of brachiopods 

across the Devonian-Mississippian boundary. This 

points up the requirement that detailed paleobio-
816 PENNSYLVANIA AND NEW YORK 

geographic and paleoecologic studies should go handin-hand with systematic descriptions of the fossils. 

Williams (1903) long ago emphasized the importance of understanding the shifting of faunas 

with depositional environments. His examples were 

drawn from the Upper Devonian of northern Pennsylvania and southern New York. The principles he 

articulated are equally applicable to the DevonianMississippian sequence of northwestern Pennsylvania today. 

Sass (1960) affirmed the Kinderhookian age of the 

Corry Sandstone in Pennsylvania and pointed out 

that correlation with the Berea Sandstone to the 

west is based on stratigraphic position rather than 

faunal evidence. He suggested (1960, p. 296) that 

the lower member of the Corry may well correlate 

with the upper part of the Bedford Shale of Ohio 

but that systematic studies of Bedford faunas are 

still needed. Sass also recognized the influence of 

environments on the invertebrates, citing the more 

common rugose brachiopod species in the eastern 

. part of the Corry as evidence of more nearshore 

conditions (1960, p. 295). On the basis of paleobotanical evidence, conodont zonation, and regional 

lithostratigraphic correlations, deWitt (1970) concluded that the basal Bedford shale may be very 

Late Devonian in Ohio and Kentucky but that the 

remaining Bedford Shale and Berea Sandstone are 

Early Mississippian. 

In southwestern Pennsylvania, emphasis has also 

been placed on locating the Mississippian-Devonian 

boundary rather than on biostratigraphic zonation. 

Laird (1941, 1942) listed invertebrates collected 

from the Devonian and Mississippian strata exposed 

in the anticlinal inliers of Fayette County. He said 

(1941, p. 18) that the occurrence of certain species 

of Syringothyris, Eumetria, Leptodesma, and Palaeoneilo mark the base of the Mississippian. The disappearance of certain species of what is now Cyrtospirifer ("Spirifer disjunctus" gens) marks the upper limit of the Devonian System. 

In 1943, Busch (p. 154) examined invertebrates 

in a shale interval in the upper part of the Shenango 

Formation in the Oil City 15-minute quadrangle in 

northwestern Pennsylvania. He concluded, on the 

basis of comparison with invertebrates of the Mississippi Valley, that the interval could be assigned 

to a series no older than middle Meramecian. Weller 

and others (1948, p. 160) questioned Busch's identifications and seriously questioned his correlation. 

They mentioned that strata overlying the Cuyahoga 

in Ohio are not known to be younger than uppermost Osagean. Szmuc (1970, p. 47) considers the 

Shenango fauna in northeAstern Ohio to bear a close 

affinity to that of the eastern part of the M~adville 

Formation (Cuyahoga Group). 

Other than what has been accomplished by Chadwick and by Caster and his students at Cincinnati, 

and what was done before the turn of the century 

by the Second Pennsylvania Survey, very little work 

has been directed toward the paleozoology of the 

Lower Mississippian of Pennsylvania. Recent work 

on trace fossils in the Devonian and Mississipian of 

northwestern Pennsylvania by Gutschick and Lamborn (1975) points to a whole new avenue of biostratigraphic analysis. Another avenue may be 

opened through conodont studies. 

The Upper Mississippian (Meramecian through 

Chesterian) is represented in Pennsylvania mainly 

by the Mauch Chunk Formation, which is dominantly nonmarine and rarely bears an invertebrate fauna. 

In the southwestern part of the State, where the 

Greenbrier limestones intertongue with the Mauch 

Chunk redbeds, some paleozoological insights have 

been obtained. Benson (1934) identified some brachiopods from a Greenbrier tongue near Uniontown, 

Pa., and concluded that the brachiopod fauna is 

similar to those of the Greenbrier Formation of 

West Virginia and the Ste. Genevieve Limestone of 

Kentucky. Haney (1963, p. 198-199) described the 

Greenbrier fauna of Pennsylvania as a principally 

brachiopod-crinoid assemblage closely related to the 

fauna of the Batesville Sandstone of Arkansas. He 

regards the Greenbrier fauna as a late Meramecian 

to early Chestrian assemblage. 

In his study of the Mauch Group in northwestern 

West Virginia, Busanus (1974, 1976) identified an 

assemblage characterized by pelmatozoans and articulate brachiopods from the Wymps Gap Limestone 

tongue of the Greenbrier. Because most of the forms 

identified in the Mauch Chunk-Greenbrier transition are relatively long ranging, Busanus (oral commun., 1978) does not believe that an Elviran (Late 

Chesterian) age for that part of the section can be 

refined. 

The Wymps Gap Limestone in Somerset County, 

Pa., as delineated by Flint (1965, p. 48), is somewhat 

above the base of the Chesterian Series. Another 

limestone called the "Deer Valley" directly overlies 

the Loyalhanna Limestone and is considered as basal 

Chesterian,. but Flint (1965, p .. 49) recommended 

further stratigraphic and paleontologic studies. 

The Mississippian-Pennsylvanian boundary is 

marked by a clear unconformity over a large part of 

Pennsylvania, as has been discussed under "Lithostratigraphy" above. Where the Mauch Chunk and 

Pottsville are interbedded, the systemic boundary 

is picked with varying degrees of confidence by 
THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 817 

paleobotanical methods. Some potential for paleozoological definition of the Mississippian-Pennsylvanian boundary in Pennsylvania may be found in 

the detailed study of freshwater arthropods and 

bivalves, but to date, no such research has been done. 

Raymond (1911, p. 95-96) presented a list of invertebrates found in the Vanport marine zone of the 

Pennsylvanian Allegheny Group, along with invertebrates in five marine zones of the Conemaugh Group. 

His list was preliminary, and no accurate biostratigraphic correlations could be inade from it. Williams (1960) identified a large fauna from the Pottsville and Allegheny Groups of western Pennsylvania 

and established the beginnings of proper paleozoological zonation within those groups. He (Williams, 

1960, p. 911) explained the necessary paleoecological 

and paleoenvironmental evaluations that are a prerequisite to accurate zonation and correlation. 

The Glenshaw Formation of the Conemaugh 

Group is characterized by several marine "zones," 

which may be genuine fossiliferous limestone beds 

or which may grade laterally to highly fossiliferous, 

carbonaceous, calcareous .siltstone. The best known 

and most widespread of these units are the Brush 

Creek, the Cambridge (Pine Creek), and the Ames. 

The Ames marine zone is used as a key bed to mark 

the top of .the Glensh~w Formation. Over much of 

their extent, these marine units may be true biostromes. Invertebrate faunal diversity appears to be 

greater in these marine zones than at any other 

horizon within the Mississippian or Pennsylvanian. 

Seaman (1940, 1941, 1942) listed a large number of 

invertebrates from these three marine zones and 

pointed out some minor differences between the 

three suites, but he did not attempt to erect biozones 

or to establish correlations with the midcontinent. 

Chow (1951) documented the occurrence of a, 

marine zone in the Llewellyn Formation called the 

Mill Creek Limestone; correlation with the Ames 

of western Pennsylvania is based on interval and 

faunal content. Further studies on the Glenshaw 

marine units have been carried out by Lintz (1958), 

Murphy (1970), Rollins and Donahue (1971), Shaak 

(1972), and Donahue and Rollins (1974). The thrust 

of recent research and investigation with regard to 

the Glenshaw marine intervals has been more to 

recognize and define fossil invertebrate communities 

and their ecosystem dynamics through time and in 

relation to sedimentation cycles (Shaak, 1972; Rollins and Donahue, 1975). Paleontological zonation by 

invertebrates in this part of the Carboniferous will 

be contingent upon the success of these paleoecological investigations. 

The upper part of the Conemaugh Group, the 

Casselman Formation, is for the most part nonmarine, and relatively little paleozoological information has been derived from these rocks. The overlying nonmarine Monongahela Group has to date 

·also yielded relatively little paleozoological data. 

Durden (1969) has provided an important avenue 

for zonation and correlation through his research 

on blattoid insects in these nonmarine strata, as 

well as in the underlying Allegheny and Pottsville 

Groups and the laterally equivalent Llewellyn Formation. 

Fossil vertebrates (fish) have been collected by 

various workers from all of the Carboniferous of 

Pennsylvania, but the most serious research on this 

topic has been carried out by Lund (1970). Continued detailed studies of fossil fishes may well provide a basis for zonation of the upper Conemaugh 

and Monongahela Group. 

PALEOBOTANY 

The floral biostratigraphy of Pennsylvania was 

investigated with considerable energy in the late 

19th and early 20th centuries, but interest has 

dwindled since, so that only a few poorly supported 

workers continue, intermittently, to pursue the subject. The most authorative summary of the floral 

biostratigraphy of the entire Mississippian-Pennsylvanian was given in Read and Mamay (1964). 

Darrah (1969) produced an extensive review of the 

Late Pennsylvanian flora. The floral biostratigraphic 

sequence shown in figure 11 is based mostly on 

Read and Mamay (1964). 

The 12 Mississippian and Pennsylvanian floral 

zones shown in figure 11 are considered biostratigraphically and chronologically sequential. At no 

single place in Pennsylvania, however, is the complete sequence found. The absence of zones 7 and 8 in 

the Southern and Middle Anthracite fields is probably a matter of nonpreservation or locally unsuitable growth environment, rather than a missing 

stratigraphic section. (See "'Nood and others, 1969, 

p. 79. 

North and northwest from the Southern Anthracite field, Lower Pennsylvanian floral zones 4, 5, 6, 

and 7 disappear, as do Mississippian zones 3 and 

2. This expanding gap in the floral sequence was explained by White (1891) as the result of widespread 

erosion at the end of the Mississippian, which successively removed the Mississippian sequence 

toward the northwest. Subsequently, onlapping sediments of the Lower Pennsylvanian Pottsville sequence advanced slowly across this erosion surface. 

The lowest Pottsville becomes progressively younger 

toward the northwest, and the older Pennsylvanian 
818 PENNSYLVANIA AND NEW YORK 

~oi" DOMINANT PENNSYLVANIA EXCEPT en ~ ~:i~ CHARACTERISTIC SOUTHERN AND MIDDLE w w SOUTHERN and MIDDLE a: 1- ---~~>- FLORAL SPECIES ANTHRACITE FIELDS en C2 ~ ANTHRACITE FIELDS w > (READ and MAMAY, 1964) en en ~!!S~ 

c: c: 

Possibly present in uppermost Llewellyn ~-~ ca 

13 Callipteris spp. Dunkard Group OE "§ Formation 3:ca CD (,) Q.. 

?-~?-

12 Danaeites spp. Upper Monohgahela Group Possibly present in upper Llewellyn Forma~ I 

tion. ·c;, c: '-CU ::;·-

11 Lescuropteris spp. 

Lower Mononga~ela Group and . Possibly present in upper Llewellyn Forma- ~ 

Casselman Formation of Conemaugh Group tion •C: 

-~·! ~::::J Neuropteris flexuosa Glenshaw Formation of Conemaugh Group Lower Llewellyn Formation 0 10 and Pecopteris spp. ·and upper Allegheny Group ~ 

c: !Jpper Sharp Mou.ntain Member of Pottsville ca c: ·;; 9 Neuropteris rarinervis Lower Allegheny Formation tormation ~nd possibly lowermost Llewel- CD ca n Formation . c: 

·s ·- Not known. Presumed equivalent to middle ~ c: 

Neuropteris tenuifolia Upper Pottsville Formation (Mercer)' (I) ca 8 Sharp Mountain Member of Pottsville For- CD 

c > mation -

> 

Not known. Presumed equivalent to lower c: (I) 

Middle Pottsville Formation (Connoquenes- ca 

7 Megalopteris .spp. Sharp Mountain Member of Pottsville For- . ~ c: 0 

sin~) ... mation <t c: 

CD 

Lowest Pottsville Formation in NW. Pa. Q.. 

Neuropteris tennesseeana and (Sharon). Absent elsewhere by disconfor- 6 Mariopteris pygmaea· mity ( nondepositiorr) and/or biofacies with Schuylkill Member of Pottsville Formation 

zone 3 

c: 

Absent by disconformity (nondeposition) Upper Tumbling Run Member of Pottsville ~ Mariopteris pottsvillea e 5 and Aneimites spp. and/or biofacies with zone 3 ·Formation 0 

~ 

\ \ . ..) .,.) 

Neuropteris pocahontas Absent by disconformity (nondeposition) Lower Tumbling Run Member of Pottsville \ \ 4 and Mariopteris evem- and/or biofacies with zone 3 Formation .,.) .,.) 

opteroides .!\ \ CD· • ..) . ..) 

;; \ \ Mauch Chunk Formation. Absent in SW. Pa. CD 

Fryopsis spp. and .r:. 3 (marine facies) and northern Pa. (Discon- M~uch Chunk Formation u Sphenopteridium spp ~ formable nondeposition and erosion) -

.c: c: 

l!.!! ca CI)U 

~e ·-

Q. Burgoon and· upper Pocono Formations. AbUpper Pocono Forma"tion ~ Q. 2 Triphyl/opteris spp. sent in northern Pa. by disconformable non- ac: ·- deposition and· erosion 

:gca (I) 

OCD (I) 

·-

(I) 

.!.C: (I) 

Upper Huntley Mountain, upper Rockwell, Upper Spechty Kopf and lower Pocono For- CD.!! 

~~ ·- 1 Adiantites spp. c:o · and lower Pocono Formations mations ·-

~.r:. 0 ~ 

FIGURE H.-Mississippian and Pennsylvanian floral zones. 
THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 819 

floral zones disappear. See the section on "Major 

Disconformities of the Mississippian-Pennsylvanian" 

for additional discussion of this subject. 

CHRONOSTRATIGRAPHY 

The time boundaries of the Mississippian and 

Pennsylvanian Periods and their subordinate epochs 

(fig. 5) are placed entirely by reference to the biostratigraphy of the rock sequence. No supplementary physical data, such as radioactive dating, are 

available. 

Of the three period boundaries involved, only the 

Devonian-Mississippian boundary in the marine 

section of northwestern Pennsylvania, and the 

boundary marked by the disconformity between the 

Pennsylvanian Pottsville and Lower Mississippian 

Burgoon (or older .strata) are located with some 

reasonable precision. The extension of the DevonianMississippian boundary eastward into the dominantly nonmarine Huntley Mountain, Rockwell, and 

Spechty Kopf Formations is primarily based upon 

interval and some general control from the plant 

fossils. 

The Pennsylvanian-Mississippian boundary in the 

Southern Anthracite area, where the Pottsville 

reaches maximum thickness, may be placed arbitrarily at the base of that unit. Because, however, 

the upper Mauch Chunk is the lateral facies equivalent of at least part of the Pottsville, the period 

boundary must pass into the Mauch Chunk at some 

point. Because there is some doubt as to what extent the Pottsville-Mauch Chunk contact is conformable or disconformable elsewhere, the position 

of the Pennsylvanian-Mississippian boundary is obscure. 

The least clear of the three period boundaries is 

that between the Pennsylvanian and Permian. The 

problem is inordinately complex. The most exhaustive examination of the location of the Pennsylvanian-Permian boundary is in "The Age of the 

Dunkard" (Barlow, 1975), a symposium in which 23 

paleobotanical and paleozoological specialists discuss 

the problem. Opinions range from placing the Permian-Pennsylvanian boundary as low stratigraphically 

as the Casselman Formation of the Conemaugh 

Group, to above the uppermost occurrence of the 

Dunkard. Much simplified, the problem centers about 

whether or not the first occurrence of the Permian 

index fossil, Callipteris conferta in the Appalachians 

corresponds chronologically with its first occurrence 

in the Permian standard section in central Europe. 

The epoch boundaries within the Carboniferous 

of Pennsylvania are poorly defined, ·except for those 

of the Desmoinesian and, in western Pennsylvania, 

the Missourian. 

DEPOSITIONAL HISTORY 

Sediments of the Mississippian and Pennsylvanian Periods were deposited upon the vast Upper 

Devonian Catskill deltaic complex. These sediments 

were derived from the southeastern orogenic uplift, which had formed along the impact margin of 

the North American and African continental plates, 

and also from the edge of the North American cratonic heartland and the older Taconic impact area 

to the north and northeast. 

The Catskill deltaic comple·x achieved maximum 

westward progradation during the late part of the 

Late Devonian (Chautauquan) (fig. 12A). Shortly 

before the end of that period, a widespread and relatively abrupt marine transgression terminated the 

Catskill deltaic complex, overrunning its upper 

surface by 80-160 km (50-100 mi) and depositing 

the Riceville Shale and Oswayo Formation (fig. 12B). 

Some thin marine tongues advanced briefly as far 

east as Clinton and Bedford Counties. The effects 

of the transgression were such that even the equivalent nonmarine Huntley Mountain, Rockwell, and 

Spechty Kopf Formations lost most of the typical 

Catskill characteristics, notably most of the distinctive red coloration. The presence of some possible 

ghtciolacustrine sediments in the Spechty Kopf and 

Rockwell (Sevon, 1969, 1973) suggests a more severe climate and the presence of glaciers in the 

orogenic highlands to the east. 

During Early Mississippian (Kinderhookian) time 

(fig. 12C), some westward progradation took place, 

but, in general, a fairly stable coastal plain was 

established, dominated by delta-lobe development 

(Demarest, 1946; Pepper and others, 1954). This 

episode was followed by the westward extension of 

the elongate anastomosing alluvial-deltaic Burgoon 

sand plain during early middle Mississippian ( Osagean) time (fig. 12D.) 

Three notable changes in the depositional environment were introduced, more or less simultaneously, in middle-Late Mississippian (Meramecian) time (fig. 12E) . Mild epeirogenic uplift across 

northwestern Pennsylvania and adjacent New York 

ended deposition in that area and initiated some 

erosion of the Burgoon and equivalents and of older 

rocks. Similar upwarping probably affected extreme 

northeastern Pennsylvania. In southeastern Pennsylvania, strong sediment influx initiated redbed 

deposition of the Mauch Chunk delta. Between the 

northwestward-prograding Mauch Chunk delta and 

the upwarped area in the northwest, a shallow re-
820 PENNSYLVANIA AND NEW YORK 

stricted embayment penetrated as far as Sullivan 

County, depositing the Loyalhanna calcareous sandstone, a lateral equivalent of the Greenbrier marine 

carbonate sequence of West Virginia (Adams, 1970; 

Wells, 1974). Influx of sand streaming off the 

wasting Burgoon to the north introduced a strong 

sand fraction to the Loyalhanna. Similarly, red 

clastic material from the advancing Mauch Chunk 

delta gave the Loyalhanna facies a strong red cast 

in places. 

During the Late Mississippian (Chesterian) and 

Early Pennsylvanian (early Morrowan) time, the 

Mauch Chunk encroached northwestward, squeezing 

out the Greenbrier-Loyalhanna embayment except 

in extreme southwest Pennsylvania (fig. 12E). The 

Mauch Chunk apparently encroached across the uplifted northwest area for some unknown, but probably limited, distance before continued uplift resulted in erosion of the Mauch Chunk margin and 

further wearing away of the Burgoon and lower 

strata. The Mauch Chunk itself was overrun from 

the southeast by the course alluvial clastic material 

of the Tumbling Run and Schuylkill Members of the 

Pottsville Formation. 

By Early-Middle Pennsylvanian (late MorrowanAtokan), Pottsville alluvial clastic deposits from the 

southeast orogenic source had spread across all but 

the northwest quarter of Pennsylvania and adjacent 

New 'York (fig. 13A). Renewed Pottsville alluvial influx from the fringes of the North American craton 

spilled across New York and northwestern Pennsylvania. The northwest and southeast Pottsville clastic deposits merged, burying almost all older rocks. 

In a narrow band across Jefferson, Clearfield, Centre, 

and Clinton Counties, however, a cuestalike erosional remnant of the Burgoon Sandstone (and, 

locally, a similar remnant of a lower Mauch Chunk 

sandstone) stood high enough to escape burial (fig. 

13A). Along the crest of these sandstone ridges, the 

unusual Mercer high-alumina flint clays formed 

(Edmunds and Berg, 1971, p. 57-61). 

A general marine transgression during Middle 

Pennsylvanian (early Desmoinesian) produced a 

shallow marine embayment across west-central 

Pennsylvania surrounded by lower and upper 

delta-plain and alluvial-plain environments (fig. 

13B) (Ferm, 1974; Ferm and Cavaroc, 1969). The 

associated sediments of the upper Pottsville and 

lower Allegheny Groups in the west, and the upper 

Sharp Mountain and lower Llewellyn Formations in 

the east are typically complex and variable. 

By late Desmoinesian time, the sea had withdrawn 

westward into Ohio, allowing deposition of the entirely nonmarine upper Allegheny Group and lower 

quarter of the Glenshaw Formation in Pennsylvania 

(fig. 13) (Ferm, 1974). 

Widespread marine invasions spread across western Pennsylvania during early Missourian time, reintroducing the shallow marine and lower deltaplain sediments associated with the upper threequarters of the Glenshaw Formation (fig. 13D) 

(Donahue and Rollins, 197 4 ; Morris, 1967). One of 

these brief marine transgressions, represented by 

the Mill Creek Limestone (Chow, 1951), went as far 

east as Wilkes-Barre, the most easterly marine 

penetration since early Late Devonian. 

The sea withdrew completely and permanently 

by late Missourian to early Virgilian time, leaving 

Pennsylvania almost isolated at the extreme northeastern end of a very restricted estuary. The Casselman Formation was deposited as alluvial-deltaic 

sediments along the estuary margin. 

By late Virgilian time, the northeastern end of 

the Appalachian basin is believed to have been 

totally severed from any marine connection, and a 

widespread lake or system of lakes formed, receiving 

the Upper Pennsylvanian Monongahela Group sediments, as well as those of the succeeding Permian ( ?) Dunkard Group (fig. 13F) (Berryhill and 

others, 1971; Donaldson, 1969, 1974). 

· The sedimentological origin of the Pennsylvania 

coal-bearing sequence has been the object of intense 

speculation for well over a century. Early studies 

attributed a high degree of lateral persistence to 

various thin lithosomes found in the Pennsylvanian 

sequence, most particularly to the coal beds (Rogers, 

1858 ; Lesley, 1879). The concept of coal bed persistence was raised to the level of official dogma 

when the boundaries of the lithostratigraphic subdivisions of the Pennsylvanian were formally defined by key bed coals. 

In the late 1920's, a standardized repetitive sequence of rock types, called the cyclothem, was devised for the Pennsylvanian of the ·midcontinent 

(Wanless, 1931). The cyclothem concept called for 

strong lateral continuity of the individual rock 

types and, by inference, cyclic repetition of widespread depositional environments, caused and controlled by basinwide geological phenomena. Local 

geological phenomena were relegated to the minor 

role of "disrupters" of what would otherwise have 

been a "normal complete" cyclothem. In the central 

Appalachians, coal seams and other rocks had long 

been presumed to be thin but enormously widespread lithosomes ; the cyclothem concept suddenly 

promised to provide the long-desired theoretical 

foundation for the assumption of widespread lateral 

continuity of lithosomes. Only Ashley (1931) tended 
THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 821 

A. UPP.ER DEVONIAN (UPPER CHAUTAUOUAN) 

PROGRADING 

DELTAIC 

SEDIMENTS 

(Catskill Formation) 

I 

I 

Maxmium northwestward progradation of the Catskill Delta. 

C. LOWER MISSISSIPPIAN (KINDERHOOKIAN) 

UPPER DELTAPLAIN 

SEDIMENTS 

(upper Rockwell 

Formation) 

Stable coast. Depositional variations controlled by deltaic switching. 

E. UPPER-MIDDLE MISSISSIPPIAN (MERAMECIAN) 

TECTONIC 

UPWARPING 

(Erosion of Burgoon 

and older units) 

Sh.allow.marine transgression between upwarped northwestern 

positive area and early stage of northwestward prograding 

Mauch Chunk Delta. 

B. UPPERMOST DEVONIAN (UPPERMOST CHAUTAUOUAN) 

FROM CRATONIC AND NE. 

OROGENIC SOURCES 

~ ~ ~.._":> ·-$><::' ·~ / / ~ "' ,y;Cfl ~ .r-~ /OJ (lower Huntley Mtn. Fm.) «.~· ,)Y ~ c..'' Q)p: ?; ~&q «.o ~ ·§Jj RETREATING o 

.j' CfJ ::\o ~0~ ~~~ DELTAIC 

~-..~ ~ ~q, ·~q, ~~4./~o SEDIMENTS 

~~ Pr, ~ i::'~'!-- ~~4. (lower Rockwell ~~ .~0 (:) cS~~,~ 0~ .... q,~ '8 ~o I . ~ \ 

\ 

\ 

I 

I 

I 

/ 

Eastward marine transgression terminates Catskill Delta. 

D. LOWER-MIDDLE MISSISSIPPIAN (OS~GEAN) 

FROM CRATONIC AND NE. 

OROGENIC SOURCES 

BRAIDED ALLUVIALDELTAIC-PLAIN SANDS 

(Burgoon Formation and 

Mt. Carbon Member) 

? 

Stagnant basin, developing braided alluvial-deltaic sand plain. 

Strong resistance to additional subsidence. 

F. UPPER MISSISSIPPIAN (CHESTERIAN)-LOWER. 

PENNSYLVANIAN (MORROWAN) 

Maximum northwestward progradation of Mauch Chunk Delta. 

Erosion of sub-Loyalhanna units in northwest. 

FIGURE 12.-Upper Devonian, Mississippian, and Pennsylvanian paleogeography and depositional environments. 
822 PENNSYLVANIA AND NEW YORK 

A. LOWER PENNSYLVANIAN (UPPER MORROWAN-ATOKAN) 

NORTHERN ALLUVIAL PLAIN 

(OieaJ sandstone ~ (Stiaron Sandstone and conglomerateC/ J ~ 

and Conglomera~e""l ? -:-~/UNBURIED / CREST ~ OF ~f..~ v~~~ 

MERCER HIGH ALUMINA BURGOON ESCARPMENT ~~~~ FLINT CLAY -~ ~ 

CONNOQUENESSING SANDSTON • ,~\t>-\.. ~~'~" \..v '1:: 

/, 

sou-rHERN /.-Q~'t.~¥:, /O~c:,_o\J / 

Pottsville alluvial sediments from northern and southern sources 

bury older units except narrow positive remnant of Burgoon 

escarpment. 

C. MIDDLE PENNSYLVANIAN (UPPER DES MOINESIAN) 

FROM CRATONIC SOURCE 

·"" \ 

I ' I 

UPPER DELTA-PLAIN I 

SEDIMENTS / 

(upper Allegheny Group and // 

lower Glenshaw Formation~/ 

/ 

n. 

/ 

/ 

/ 

General progradation displaces lower delta-plain and marine environments westward into Ohio. 

E. UPPER PENNSYLVANIAN (UPPER MISSOURIAN AND 

LOWER VIRGILIAN) . 

FROM CRATONIC SOURCE 

RESTRICTED 

ESTUARINE-MARGIN 

DEL TAlC SEDIMENTS 

(Casselman Formation) 

I 

I 

n. 

I 

I 

/ 

I 

/ 

. ..,) 

\ 

I 

I 

I 

/ 

Northern end of the Appalachian Basin reduced to shallow estuary, remote from open marine conditions. 

B. MIDDLE PENNSYLVANIAN (LOWER DESMOINESIAN) 

FROM CRATONIC SOURCE 

General transgression producing embayment coast. Complex 

lithologies largely controlled by delta switching. 

D. MIDDLE -UPPER PENNSYLVANIAN (LOWER MISSOURIAN) 

Series of abrupt, widespread marine transgressions. 

F. UPPER PENNSYLVANIAN (UPPER VIRGILIAN) 

;· 

LACUSTRINE AND 

LACUSTRINE-MARGIN 

DEL TAlC SEDIMENTS 

(Monongahela 

Formation) 

/ 

/ 

' ' I 

I 

I 

I 

I 

I 

/ 

Northern end of Appalachian Basin detached from marine conditions. 

FIGURE 13.-Pennsylvanian paleogeography and depositional 

environments. 
THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 823 

to reject the existence of a detailed Appalachian 

cyclothem. 

Decades were spent trying to fashion the Appalachian cyclothem or cyclothems (Stout, 1931; 

Reger, 1931; Beerbower, 1961; Branson, 1962; 

Sturgeon and others, 1958). Eventually, it became 

apparent that no single cyclothem or reasonably 

small number of cyclothems could be devised for 

the Pennsylvanian of the central Appalachians, because of the very limited vertical or lateral lithic 

continuity. 

In the past 30 years, a huge body of fact and 

theory has evolved dealing with sediments and processes of modern coastal plains. The application of 

these concepts (Ferm, 1974; Donaldson, 1974) to 

the Pennsylvanian rocks of the central Appalachians 

has provided the key to understanding the Pennsylvanian sequence in all its lithologic complexity and 

variability without resorting to oversimplification. 

It seems reasonably certain that the deposition 

of individual Pennsylvanian lithosomes is not controlled entirely by basinwide agencies, but rather by 

relatively local conditions of sedimentation having 

relatively little areal extent and even less temporal 

persistence. Basinwide sedimentation controls are 

only overprinted on dominantly local controls. Basinwide geological phenomena did produce most of the 

gross character of the Pennsylvanian, or large parts 

of it, such as: the general presence or absence of 

redbeds, marine units, or freshwater limestones; 

the average thickness of coal beds ; and the overall 

coarseness of the clastic fraction. Basinwide phenomena did not, however, dictate the lithology or 

vertical and horizontal arrangement of individual 

lithosomes. 

ECONOMIC GEOLOGY 

COAL 

Coal fields.-Pennsylvania, which is at the northern end of the Appalachian coal basin, has about 

39,000 km2 (15,000 sq mi) that is underlain by one 

or more coal beds. 

Geographically, the coal-bearing areas of Pennsylvania can be divided into the following fields (fig. 

14): 

1. Main Bituminous field. 

2. George Creek (Wellersburg) field. 

3. Broad Top field. 

4. North-Central fields (five small fields). 

5. Northern Anthracite field. 

6. Western Middle Anthracite field. 

7. Eastern Middle Anthracite field. 

8. Southern Anthracite field. 

More than 90 percent of current production comes 

from the Main Bituminous field. 

Rank and heat value.-Pennsylvania coal ranges 

in rank from high-volatile bituminous to anthracite; 

rank increases from west to east (fig. 15). Fixed 

carbon content ranges from 55 to 97.5 percent (dry, 

ash-free proximate analysis) 

On a dry, ash-free basis, the heat value of Pennsylvania coal increases from an average low of about 

8,200 cal/g (14,700 Btu/lb) in Beaver and Lawrence 

Counties to an average maximum of 8,800 cal/g 

( 15,800 Btu/lb) in northern Somerset and southern 

Cambria Counties, and in the Broad Top and Georges 

Creek fields. From this high; the heat value decreases with increasing rank to a minimum of about 

8,000 cal/ g ( 14,400 Btu/lb) in Carbon County. Mined 

coal on an as-received basis will generally yield 550 

to 1100 cal/g (1,000 to -2,000 Btu/lb) less than the 

dry, ash-free value. 

Sul/u1· content.-Although the sulfur content of 

Pennsylvania coal can vary widely for any one seam, 

even on a local scale, the following· two genera]izations apply: (1) the average sulfur content of coal 

seams increases westward, and (2) the stratigraphically lower mineable coals tend to contain more sulfur. In both generalizations, the high concentration 

of sulfur is related to the brackish to marine depositional environment interpreted for the overlying 

clastic sediments. 

Most coal in the anthracite fields contains 0.5 to· 

1.5 percent sulfur. The Pennsylvania anthracite 

fields represent one of the largest reserves of lowsulfur coal in the Eastern United States. 

Main Bituminous field coal is mostly high-sulfur 

(more than 2 percent S), perhaps 5 to 10 percent of 

the coal is low-sulfur (less than 1 percent S), and 

25 to 30 percent is medium-sulfur (1 to 2 percent S). 

Much of the low-sulfur reserves are concentrated in 

the Pittsburgh seam. 

The small reserves of the Georges Creek and 

Broad Top fields are medium-sulfur; those of the 

North-Central fields are low- to medium-sulfur. 

Coking potential.-Except for minor nonbanded 

varieties, all Pennsylvania coal cokes to a degree 

expected of its rank. That is, the bituminous coal 

cokes well, and the anthracite and semianthracite 

coal cokes poorly, or not at all. 

Bituminous coal usually has a free swelling index 

of 5 to 9 and an agglutinating value of 6.5 to 11.0. 

Most medium- and high-volatile bituminous coal contracts upon coking, whereas low-volatile bituminous 

coal expands strongly. The low-volatile coal is especially valuable for upgrade blending with more 

abundant high-volatile coal. 
824 PENNSYLVANIA AND NEW YORK 

t.-=-~=-i:25======:550 ____ 7ii5====:::=::::3190 MILES 

FIGURE 14.-Goal fields of Pennsylvania. 

Results of ASTM coke strength tests indicate that 

Pennsylvania coals behave as would be expected of 

their rank, although individual samples may vary 

considerably. If properly blended, most Pennsylvania 

coke will have adequate strength. 

On an as-received and as-carbonized basis, Pennsylvania coal usually produces the following percentage of coking products: coke-66 to 81 percent, 

gas-10 to 17 percent, tar-2 to 9 percent, and ammonium compounds-4 to 10 percent. The percentage of coke increases and the percentage of 

other products decreases with increasing rank. 

High sulfur content is the persistant detrimental 

factor in the use of Pennsylvania coal for coking 

purposes. 

Anthracite, semianthracite, and nonbanded bituminous coal are nonagglomerating and noncoking. 

A small amount of anthracite is used in some coke 

blends and in foundry coke. 

In 1975, Pennsylvania produced 26 million tons of 

coal for coke manufacture, largely from Washington, Greene, Allegheny, Westmoreland, and Cambria 

Counties. 

Mining and production.-In 1976, 820 mining 

companies in Pennsylvania produced 85,591,169 t 

(metric tons) (91,039,650 short tons) of coal from 

2,038 mines. Of this total, 29 companies and affiliates 

produced 41,595,051 t (45,849,925 short tons) or 

about 50 percent. Table 1 summarizes coal production for 1976. 

Resources.-The estimated recoverable coal resources of Pennsylvania as of January 1, 1970, are 

summarized in table 2 (Edmunds, _1972). Production 

since January 1, 1970, has been about 32 million t 

of anthracite and 650 million t of bituminous. 

In-place coal resources for Pennsylvania are approximately 57 billion t of bituminous in beds more 

than 46 em (18 in.) thick and 15 billion t of anthracite in beds more than 61 em (24 in.) thick. , 

Coal-seam correlations.-All significant coal 
THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 825 

O-==-~lllli:25::::::=:=::::i50 .... ___ 7iC5==:==:==::::l100 MILES 

FIGURE 15.-Isocarb map of Pennsylvania. 

seams of Pennsylvania are of PennsylvanianPermian age and thus are broadly equivalent 

throughout the State. The lowest (Lykens) coals of 

the Southern and Western Middle Anthracite fields 

are somewhat older (Morrowan) than any other coal 

in the State, and the highest Permian coals in the 

southwest corner of the Main Bituminous field are 

the youngest. 

Many of the difficulties in determining the properties and extent of individual coal seams stem from 

the custom of considering each coal as a single, indefinitely continuous bed. Most coal names (such as 

Brookville, Lower Freeport, Sewickley, etc.) actually 

represent several areally limited individual coal 

lenses, or multiply-split coal complexes at about the 

same stratigraphic position within the coal-bearing 

sequence. Except for the extraordinarily widespread 

Pittsburgh coal, most coal seams appear to be continuous for at most several thousand square kilometers and usually very much less. 

Keeping in mind the fact that individual coal 

names represent similar stratigraphic position more 

than actual bed continuity, customary seam nomenclature within each of the coal fields is as shown 

in figure 16. 

OIL AND'GAS 

Thousands of wells drilled in western Pennsylvania, primarily for Upper Devonian objectives, have 

penetrated the Carboniferous section. Commercial 

quantities of both oil and gas have been discovered 

within the Carboniferous of western Pennsylvania 

(fig. 17), although this production is at present relatively small in comparison with production from 

Upper Devonian rocks. 

Mississippian system.-The Mississippian System 

in the subsurface of western Pennsylvania comprises, in upward succession, the Pocono Group, the 

Greenbrier Group, and the Mauch Chunk Formation. 

The Pocono Group (used here as a subsurface term) 

consists of sand and shale and contains several 
826 PENNSYLVANIA AND NEW YORK 

TABLE I.-Pennsylvania coal production (meflric tons), 1976 

[Data from Pennsylvania Dept. Environmental Resources, 1977] 

Bituminous Anthracite Combined 

Type mine Tonnage 

Deep --------------~--------------------- 40,214,887 

Strip ------------------------------------ 36,507,906 

Culm and silt bank reprocessing ---------- 784,249 

Auger ----------------------------------- 283,428 

Total ------------------------------ 77,790,470 

hydrocarbon-bearing horizons. These include the 

Murrysville or Cussewago sand (considered to be the 

basal Mississippian unit in the subsurface), which is 

the most important natural-gas-producing horizon 

within the Carboniferous. The Berea sand is stratigraphically above the Murrysville and is the most 

important oil-producing horizon within the Carboniferous. The Berea is stratigraphically equivalent 

to the Corry sandstone but has a different source 

area. The detailed stratigraphic relationships of the 

Murrysville, Berea, and Corry sands have been studied by Pepper and others (1954). Other productive 

sands within the Pocono Group· include, in upward 

succession, the Squaw, the Shenango or Slippery 

Rock, and the Big Injun or Burgoon sands. 

The Loyalhanna, which is commonly a sandy lime-· 

stone, is a transitional unit between the underlying 

Big Injun sand and the overlying Greenbrier limestone. The Loyalhanna and Greenbrier are not known 

to be productive in western Pennsylvania. The 

Mauch Chunk red shale overlies the Greenbrier 

Group. The top of the Mississippian System is 

marked by a major unconformity, and in the subsurface, the Mauch Chunk, Greenbrier limestone, and 

Loyalhanna are successively truncated to the north 

by this unconformity. 

Pennsylvanian System.-In the subsurface Pennsylvanian System of western· Pennsylvania, the 

Pottsville Group includes the hydrocarbon-bearing 

Maxton s·and, also referred to as the Third Salt or 

Lower Connoquenessing sand, the Second Salt or 

Upper Connoquenessing sand, and the First Salt or 

Homewood sand. The Salt sands produce brine and 

are also the largest gas producers within the Pennsylvanian System. 

The Allegheny Group includes three productive 

sands: the Clarion or Lower Gas sand ; the Kittanning s·and, also known as the Middle Gas sand or the 

First Gas sand ; and the Upper Freeport or Upper 

Gas sand. The top of the Allegheny Group is the 

Upper Freeport coal. The Upper Freeport coal conNumber of Number of Number of 

mines Tonnage mines Tonnage mines 

159 468,437 109 40,683,324 268 

1,498 2,683,602 119 39,191,508 1,617 

16 1,648,660 73 2,432,909 89 

64 None None 283,428 64 

1,737 4,800,699 301 82,591,169 2,038 

tains large quantities of methane; in the future, 

this unit may become an important source of natural 

gas. 

The Conemaugh Group includes several producing 

sandstone units: the Big Dunkard, also referred to 

as the Hurryup or the Mahoning sand ; the Little 

Dunkard or Buffalo sand; the Saltsburg sand; and 

the Murphy or Morgantown sand. The Saltsburg 

sand is the most important oil-producing unit within 

the Pennsylvanian System, and the Big and Little 

Dunkard, which in places merge into one sand referred to as the Dunkard, are together second in importance for the production of oil in the Pennsylvanian System. The Dunkard was the first oil-bearing unit discovered in the Carboniferous ; the first 

producing well was drilled in 1863, just 4 years after 

the Drake discovery. The Murphy or Morgantown 

sand is· the highest producing sandstone within the 

Carboniferous. 

One other unit must be mentioned within the 

Pennsylvanian System-the Pittsburgh coal, at the 

base of the Monongahela Group. Commercial quantities of pipeline-quality gas are being produced from 

the Pittsburgh coal. Since 1964, the U.S. Bureau of 

Mines has conducted a comprehensive methane-control research program. Three programs are currently underway in Washington County using methods devised by the U.S. Bureau of Mines to extract 

methane for commercial purposes from the Pittsburgh coal prior to mining. Gas obtained from coal 

demethanization could become an important resource 

in the future. 

Nature of traps.-The traps within the sandstone 

units of the Carboniferous appear to be controlled 

by lithologic characteristics and minor local structural control. Production is dependent upon porosity, 

which in turn is dependent upon the original conditions of accumulation of the sediments and their 

later cementation. Production is in porous and permeable lenticular sandstone which varies greatly in 

persistence, texture, and thickness. 
TABLE 2.-Reco1Jerable coal resources of Pennsyl1Jania in beds more than 61, '!1, and 91 em thick, by counties ctmd ra:nk, Cl8 of January 1, 1970 

(miUions of metric tons) 

[Data from Edmunds, 1972. Figures are rounded to first two digits (first digit 9 mUUon or less). Numbers w1ll not total exactly because of independent rounding) 

Recoverable reserves more than 61 em thick Recoverable reserves more than 71 em thick Recoverable reserves more than 91 em thick 

COUNTYt High- Medium- Low- Semi- High- Medium- Low- Semi- High· Medium- Low· Semi· ~ volatile volatile volatile an- An- volatile volatile volatile an- .An- volatile volatile volatile an- Anbitumi- bltuml· bitumi- thra· thra- bltuml- bltumi- bttumi- thra- thra- bitumi· bltumi- bitumi- thra- thra- = trj 

Total no us no us no us cite cite Total no us no us no us cite cite Total no us no us no us cite cite :s: 

00 

00 - MAIN BITUMINOUS AND GEORGES CREEK FIELDS -

00 

00 

-

"'tt 

Allegheny ------- 770 770 620 620 240 240 "'tt 

Armstrong ------ 1,100 1,100 ----

---- ----

---- -------- ----

---- 960 960 -------- ---- ----

---- ---- ----

---- 750 750 ----

---- ----

---- ----

---- ----

---- -> 

Beaver --------- 620 620 ---- 320 320 ---- ---- 180 180 ---- ---- ---- .z ---- ---- ---- Blair ----------- 10 ----- 7 3 ---- ---- 8 ----- 6 2 ---- ---- 3 2 1 ---- ---- > 

Butler ---------- 1,000 1,000 ---- ---- 780 780 ---- ---- 330 330 

Cambria -------- 1,300 ----- 510 790 ---- ---- 910 ----- 360 550 ---- ---- 350 ---- 150 200 ----

---- ----

---- ~ Cameron -------- 17 11 6 ---- ---- ---- 11 7 4 ---- ---- ---- 0 0 0 ---- ---- ---- "'tt 

Centre ---------- 110 110 75 75 3 3 ---- trj ---- ---- ---- ----- ---- ---- ---- ---- ---- .z Clarion --------- 570 570 ---- ---- ---- ---- 410 410 ---- ---- ---- 73 73 ---- ---- ---- .z Clearfield ------- 910 230 880 ---- ---- ---- 650 160 490 ---- ---- ---- 82 20 62 ---- ---- ---- 00 

Clinton --------- 14 14 ---- ---- ---- 9 9 ---- ---- ---- 5 ----- 5 ---- ---- ---- ~ 

Eik ------------- 130 130 ---- ---- ---- 100 100 ---- ---- ---- ---- 42 42 ---- ---- ---- ---- t'l 

Fayette --------- 2,300 1,800 500 1,900 1,500 400 ---- ---- ---- 1,000 750 250 ---- ---- ---- < ---- ---- ---- Greene > ---------- 4,100 4,100 ---- ---- ---- ---- 3,600 3,600 ---- ---- ---- 2,500 2,500 ---- ---- ---- ---- .z Indiana --------- 2,000 1,500 500 ---- ---- ---- 1,500 1,100 400 ---- ---- ---- 570 430 140 

Jefferson -------- 1,000 1,000 ---- ---- ---- ---- 800 800 ---- ---- ---- ---- 240 240 ---- ----

---- ----

---- ----

---- -> 

Lawrence ------- 150 150 140 140 ---- ---- ---- ---- 70 70 ---- ---- ---- ---- .z ---- ---- ---- ---- McKean -------- 120 120 ---- ---- ---- ---- 87 87 ---- ---- ---- ---- 5 5 ---- ---- ---- ---- r::n 

Mercer --------- 100 100 ---- ---- 74 74 ---- ---- ---- 19 19 ---- ---- ~ 

r::Jl Somerset ------- 1,900 ----- 950 950 ---- ---- 1,500 ----- 750 750 ---- ---- 610 ----- 310 300 ---- ---- ~ Venango 110 110 ---- ---- ---- ---- 73 73 ---- ---- ---- ---- 7 7 ---- ---- ---- ---- trj 

VVashington ----- 3,900 3,900 ---- ---- ---- 3,500 3,500 ---- ---- ---- ---- 2,400 2,400 ---- ---- ---- iS: Westmoreland ___ 2,000 1,500 500 ---- ---- ---- 1,800 1,400 400 ---- ---- 1,200 960 240 ---- ---- r::n 

Field totals 24,000 18,000 4,000 1,700 20,000 16,000 2,900 1,300 10,000 8,800 1,200 500 ---- ---- ---- ---- ---- ---- -.z 

~ 

= BROAD TOP FIELD trj 

~ 

.z 

Bedford -------- 64 ----- ---- 64 ---- ---- 60 ----- ---- 60 ---- ---- 52 ----- ---- ---- 52 ---- -

~ 

Fulton ---------- 9 ----- ---- 9 ---- ---- 7 ----- ---- 7 ---- ---- 4 ----- ---- 4 ---- ---- t.%J 

Huntingdon ----- 22 ----- ---- 22 ---- ---- 16 ----- ---- 16 ---- ---- 5 ----- ---- 5 ---- ---- ~ 

Field totals 94 ----- ---- 94 ---- ---- 83 ----- ---- 83 ---- ---- 61 ----- ---- 61 ---- ---- 00 

~ 

> 

~ 

NORm-CENTRAL FIELDS trj 

00 

Bradford ------- 5 ----- ---- 5 ---- ---- 4 ----- ---- 4 ---- ---- 1 ----- 1 

Lycoming ------- 21 ----- 21 ---- ---- ---- 15 ----- 15 ---- ---- ---- 4 ----- 4 ---- Sullivan -------- 4 ----- ---- ---- 4 ---- 3 ----- ---- ---- 3 ---- 0 ----- ---- ---- 0 

Tioga ---------- 17 ----- 17 ---- ---- ---- 12 ----- 12 ---- ---- 4 ----- 4 ---- Field totals 47 ----- 38 5 4 ---- 34 ----- 27 4 3 ---- 9 ----- 8 1 0 ---- OJ 

N 

~ 
TABLE 2.-Recover.able coal resources of Pennsylvania in beds more tl~an 61,71, and 91 em thick, by counties amd rank, as of January 1, 1970-Continued 

(millions of metric tons) 

[Data from Edmunds, 1972. Figures are rounded to first two digits (first digit 9 million or less). Numbers wiU not total exactly because of independent rounding] 

Recoverable reserves more than 61 em thick Recoverable reserves more than 71 em thick 

COUNTYl 

Carbon --------- Columbia ______ _ 

Dauphin -------- Lackawanna ___ _ 

Lebanon ------- Luzerne -------- Northumberland _ 

Schuylkill ------- Susquehanna ___ _ 

Wayne ---------

Field totals 

PennsylTotal 

140 

210 

310 

150 

430 

740 

850 

4,400 

2 

3 

7,300 

vania total 31,000 

High- Medium· Low- Semivolatile volatile volatile anbitumi· bitumi· bitumt- thraAnthrano us no us nous cite cite 

140 

210' 

150 160 

150 

430 

740 

280 560 

400 4,000 

2 

3 

830 6,500 

Total 

Highvolatile 

bituminous 

Medium- Low- Semivolatile volatile anbitumi- bitumi- thra· 

nous nous cite 

ANTHRACITE FIELDS 

300 150 2 

410 

2 

TOTALS 

18,000 4,000 1,800 830 6,500 20,000 16,000 2,900 1,400 3' 

1 Excludes small recoverable reserves from Crawford, Erie, Forest, Potter, Warren, and Wyoming Counties. 

Anthracite 

150 2 

410 2 

•2 

Recoverable reserves more than 91 em thick 

Total 

10,0004 

High· Mediumvolatile volatile 

bitumi· bitumi· 

nous nous 

8,800 1,200 

Low- Semi· 

volatile anbitumi· thranous cite 

560 04 

An· 

thracite 

2 Reserves In beds more than 71 em thick cannot be separately calculated, but in most cases should be 90 percent or more of the tonnages In beds more than 61 em thick. 3 Reserves In beds more than 91 em thick cannot be separately calculated. 

4 Excludes counties of the Anthracite fields. 

c;g 

1\) 

00 

'1:1 

trj 

z 

z 

00 

to< 

t"4 

~ z 

~ 

> 

> z 

t:j 

z 

trj 

~ 

to< 

0 

~ 

~ 
THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 829 

1:! COAL SEAMS OF THE MAIN ~<i~ u COAL SEAMS ~i~ COAL SEAMS OF THE SOUTHERN, W<i_cJ> 8t: BITUMINOUS AND GEORGES CREEK ;2>w 8t: OF THE BROAD TOP FIELD ... z ;2>w t: WESTERN-MIDDLE AND EASTERN- ~~ffi FIELDS ~ffit;; ... z a:f- z MIDDLE ANTHRACITE FIELDS wwti:i s;:, s=> www ::::> 

\!) (Principal mined seams in capital letters) <~~ \!) (Principal mined seams in capital letters) ~~~ (Principal mined seams in capital letters) ~~~ 

? No. 29 

BOO Unnamed coal 

Windy Gop 400 No. 28 c.. 1200 

c.. ~ G ROGERS => 

Q Ninoveh a: 700 => ., ...: 300 No. 27 0 ~ 

~ z McQue 

z Fish Crook 8 1100 

=> 

0 

Ton Milo 600 No. 26 fl1qsquito Hollow h1pps 200 Jollytown Speer 

? KELLY No. 25 1000 

~=~~~s~t~r~ "B" 

Waynesburg "A" Dudley 500 WAYNESBURG Barnettstown No. 24 

J!\~rn 100 Uniontown No. 23 

? UL ON 900 Gordon SEWICKLEY 

Fishpot ~~~ No. 22 REDSTONE 400 ~>~ 

PITISBURGH Faust I No. 21) Littlo Pittsburgh 

Franklin BOO Lonaconing 

c.. Upper Clarysvillo Rabbit Hole (No. 20) => 

Q Lower Clarysvillo 

., 

a: Wollorsburg 300 

G Berton (Elk Lick) Fodorol Hiii(Ouquosno) u COAL SEAMS OF THE ~~~ 

Tunnoi(No. 19) => 

~ Harlom 

Uppor Bakerstown §~ NORTHERN ANTHRACITE FIELDS ffiffi~ PEACH MOUNTAIN (No. 18) 700 z Lowor Bakerstown s;:, (Principal ":lined seams in capital letters) ~~~ 8 \!) UTILE TRACY (No. 17) 

Brush Crook 200 Upper Four-Foot (No. 16Y2) 

Mahoning TRACY jNo. 16) 

UPPER FREEPORT IE) Little Chnton (No. 15V:!) 

ffig; LOWER FREEPORT (0) No. 11 Clinton (No. 15V•) 600 UPPER KITIANNING (C') No. 10 600 UTILE DIAMOND (No. 15) 

XC MIDDLE KITIANNING (C) No.9 Leader (No. 14Yz) 

~Ill hOWER KITIANNING (B) No.8 DIAMOND (No. 14) 100 

CL~~YI~l) No.7 Diamond Loader (No. 14l) 

~P~f~V orci~ No.6 

No.5 UTILE ORCHARD (No. 13) 

NO.4 500 500 Quakertown ORCHARD (No. 12) 

Sharon NO.3 PRIMROSE (No. 11) 

No.2 Rough (No. lOY:!) 

"0 

400 HOLMES (No. 10) a; 400 LOWER FOUR-FOOT (No. 9Yz) u: 

"' MAMMOTH TOP SPLIT (No. 9) :0 

"0 

!:! COAL SEAMS W;j(/) SNAKE ISLAND MAMMOTH MIDDLE SPUT(No.8Yz) ~ 9~ OF THE NORTH-CENTRAL FIELDS ~~ffi ABBOTI (8-FDDT) MAMMOTH LOWER SPLIT (No. 8) ~ wwti:i 51;, (Principal mined seams in capital letters) ~~~ SKIDMORE (No. 7) \!) KIDNEY (MILLS, &-FOOT) 300 ~ Skidmore Leader (No. 7L) w 300 

~ 100 HILLMAN (4-FOOT) ~D~~N~~BM~rN No. 51 Rock 

~~CI) SEYMOUR (CUSHING) TOP DIAMOND Lln'LE BUCK MTN. (No. 4) s:«~c.. 

~~~ iR:~t~ BOTIOM DIAMOND rs1 t TOP ROCK 6T. CHECKERt } 

oor fruok BOTIOM R CK (B. CHE KER) (LANCE) scorn STEEL c..~ 200 200 ...: Kidney TOP BALTIMORE (T.GRASSYG T.P~~STON) 

R~iiTil-~T mTIMORE (B. RA • 

TOP NEW C UNTY Lykens Volley NO. 1 (T. MARCY, T. TWIN) BOTIOM NEW COUNTY 18. MARCY,B.TWIN) Lykens Valley NO. 1 V:! 

~%h~~~J~f1~8~bM ROSSI LYKENS VALLEY NO. 2 Lykens Valley NO. 3 

TOP RED ASH (DUNMORE NO. 1) 100 Lykens Valley No. 3V:! 100 Lykens Valley No. 3't'4 MIDDLE REO ASH (DUNMORE NO. 2) Lykens Valley No. 31

/a LOWER REO ASH (DUNMORE NO. 3) LYKENS VALLEY NO.4 

~~~ DUNMORE NO. 4 ("A") LYKENS VALLEY NO. 5 LYKENS VALLEY NO. 6 

~>~ Lykens Valley No. 7 

FIGURE 16.-Pennsylvania coal-seam nomenclature. 

CLAY AND SHALE 

The Pennsylvanian-Mississippian sequence is the 

source of materials suitable for producing a wide 

variety of ceramic products including all grades of 

refractories, most types of brick and tile, lightweight 

aggregate, and stoneware. The Allegheny Group 

and uppermost Pottsville Group (Mercer Formation) 

of western Pennsylvania are the most important 

sources, yielding most of the refractory-grade clay 

and lightweight aggregate, as well as much clay and 

shale suitable for most other types of brick and tile. 

The Conemaugh and Monongahela Groups, the Rice-
830 PENNSYLVANIA AND NEW YORK 

MC DONALD AREA (A) 

UI'PER WASHINGTON LIMESTONE 

JOLLYTOWN COAL 

METERS 200 FEET 

l-500 

1-

1-400 

~ ~------,---- -~-

~-------i c i

1 i i , __ j____ --+---,--\ I I" I ' I ' 

1------1 WASHINGTON COAL 

1-------11----f-----1 WAYNESBURG COAL 

100-f--300 

-

,-----~ I -J '- ! r,' I J:.~...._, i 

1 I - l ~r-·--L 

......_ __ --1 SEWICKLEY COAL 

1------+----t PITTSBURGH COAL 

~· ·;;· ~· ·;;· ;;· ·;;·~· MURPHY SAND, MORGANTOWN SAND !:= AMES LIMESTONE 

~~~~ SALTSBURG SANDSTONE 

t2· ·~· ~· 2· ·~· ~· ~· LlffiE DUNKARD SAND, BUFFALO SAND 

.-:·:·:-.• •••• •••• Bl~fHU~N~~~~~~D, HURRY UP SAND: 

1-~--+----1 UPPER FREEPORT COAL 

1-------1 LOWER FREEPORT ~OAL 

-200 50--

-100 

- o---o 

BUTLER AREA (B) 

~~~~.AMES LIMESTONE p.; PITTSBURGH REDS 

·-- .· . . ·~.-:--=--~~ BUFFALO SANDSTONE BRUSH CREEK COAL 

' r-- I • t·---y ·' I I I I .. l,.,-",-/1 I r 

I I B I ----1 I ---' I I ' I t I I ) L-- .C--~ : j- -~ ;' I • / ~ 

L / , '--{ / ( " -< I '1'-o., I . I '\. ,I "'""""-'') ) I I /11. I J ,..._ I I ~""> 1 ,~-'--1 ,r .. .Jt, -~ I I 

: ;:-~./'"-/ I I 

t, .. ---" I . I ' ; I I ;' I ) ~ I L ____ ..!'---- -1------L--.LMAHONING SHALE. LIMESTONE, SANDSTONE 

~G~fA F~tFfr!IJ~ ~?f}J: SAND, UPPER GAS SAND 

UPPER KITTANNING COAL 

~----1 MIDDLE KITTANNiNG COAL 

~~~s KITTANNING SANDSTONE, MIDDLE GAS SAND LOWER KITTANNING COAL 

r-~=----t:i ... :::~ .. :::'~~.:::::· .. ·:::· .. ~:0 .. ~:.~:.~·1 .. :r::FIR::ST;":S;:AL;;T::SA;::N;;;-D,-;;H~OM-;;EW;;,;O;;;;O;;-D ;;:;SA:OoiNorr-----~:-~;.:;:-;~.;~.;.~:-:;-:::t.·.' -~hE~:;!:ESAND, LOWER GAS SAND 

SECOND SALT SAND. CONNOQUENESSING SAND -MERCER COAL SHEFFIELD AREA (C) 

r--~lffi~~~=~·:·~· ··~···~·~·~· ·~··. ~~R"te1~~~.V:.~JfJr~ifT· LOWER CONNOQUENESSING • • • P&~~ ~OO~~~:EE~Ets~~~ ~~~~S:ri-~~~ BROOKVILLE COAL 

I GREE~RIER LOYALHANNA LIMESTONE ·.~-s:~~~. LOYAL~ .:-:.:-:•:-:.;.:: •• : ~OE~~O~~~:.NgOAL 

~ ·~~ ... ·:.~:.·;:.·i.~.i ""NJUN SANO ::::::::::;:::;:::: .,,.OOH SANIISTONE{MOI""'· SANOI ,f't~':fj :7:"'""""""'" 

z 

<! 

z 

0 

(ij 

0 

CD ~--=---=--== PATTON SHALE 

}.:{:/{:~ SHENANGO SANDSTONE (SLIPPERY ROCK SAN.DSTONEI ."';""...:.. • ... :.,:r.·; 

........ SQUAW SAND :::::::::::::::::~ SHENANGO·CUYAHOGA SAND 

•••••• ••••• ••••••• SECOND GAS SANDJ BEREA-CORRY SAND Gt.t~: + CORRY 

"""··,...... """" .......... ,....,,, ....... ,.,,...,; • .-.I, MIIRRV!:VILI ~ SAND BUTLER (THIRTY FOOT SANDI ·~ MURRYSVILLE SAND. (GAS SANDI. CUSSEWAGO SAND ::;.;:~~·;· :~;;~: KNAPP 

DRAKE SAND~-=~ RICEVILLE SHALE 

; :: •• ·..:.,· • .:..·...:.,. GANTZ SAND } HUNDRED FOOT SAND ~·~·~:): = .. }4. FIFTY FOOT SAND} ~~~~.:~g ~~~~~:~I :-:.;:,·.·;:·:·.·: FIFTY FOOT SAND 

FIGURE 17 .-Generalized columnar section showing stratigraphic position of oil- and gas-bearing sands in Mississippian and Pennsylvanian rocks of western Pennsylvania. 

ville-Oswayo to "Hempfield" sequence, and, to a lesser degree, the Mauch Chunk Formation provide raw 

material for most types of nonrefractory brick and 

tile. Because of their high content of coarse clastic 

materials, the Pocono, Burgoon, Huntley Mountain, 

Rockwell, Spechty Kopf, Pottsville (except Mercer), 

and Llewellyn have only limited potential for ceramic 

products. 

in small outliers on the hilltops in the nonglaciated 

part of southwestern New York, in Allegany, Cattaraugus, and Chautauqua Counties (fig. 1). The 

rocks consist of thin shale, sandstone, and conglomerate of marine and alluvial origin, in nearly 

flat-lying beds that have a gentle regional dip in a 

southerly direction. Rocks of Early Mississippian 

age are unconformably overlain by those of Early 

Pennsylvanian age. However, the Pennsylvanian 

rocks may be found directly upon the latest Devonian 

strata where Mississippian rocks are absent. 

CARBONIFEROUS ROCKS OF NEW YORK STATE1 

By LAWRENCE V. RICKARD 2 

The Carboniferous rocks of New York State are 

1 Published by permission of the Director, New York State Museum, 

.Tournai Series No. 246. 2 New York State Museum-Geological Survey, Albany, N.Y. 12224. 

Among the earliest investigations of these beds, 

the most significant was. that conducted in Cattaraugus County (Salamanca and Olean 15-minute 

quadrangles) by Glenn (1903) and Butts (1903) . 

Subsequently, except for much later work by Caster 
THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 831 

(1934) and Holland (1958), these rocks have received little attention. The stratigraphic column, 

given below, is a simple one, there being only three 

units in New York State. 

Pennsylvanian Period 

Pottsvillian Series 

Sharon Shale 

Olean Conglomerate 

Mississippian Period 

Kinderhookian Series 

Knapp Formation 

The Knapp Formation (Glenn, 1903) consists of 

two units of conglomerate or sandstone; shale is 

found above and between these units. Caster ( 1934) 

proposed formal names for some of these divisions 

based on exposures in northern Pennsylvania, but 

the names have not been used in New York. The 

Knapp overlies the Oswayo shale and sandstone of 

the latest Devonian and is unconformably overlain 

by the Olean conglomerate of Early Pennsylvanian 

age. The type section of the Knapp Formation is at 

Knapp Creek Station, near "Olean Rock City" in Cattaraugus County. The formation is about 18 to 32 

m thick and is restricted to that county, although 

several outliers extend westward across the line into 

Chautauqua County. 

The Knapp shale is described as sandy, olivegreen, or rusty brown. The conglomerate, often 

limonitic, contains loosely cemented flat or discoidal 

quartz pebbles. Both units may be fossilliferous; 

brachiopods, pelecypods, and some plants have been 

found. Holland ( 1958) concluded that the considerable differences in the brachiopod faunas of the 

Knapp and the underlying Devonian strata confirmed 

the Mississippian age of the Knapp. The formation 

is not everywhere present beneath the Olean Conglomerate. 

The Olean Conglomerate (Lesley, 1875) varies 

from a coarse cream-colored quartz sandstone containing few pebbles to a conglomerate almost entirely composed of pebbles. There is much rapid 

variation, both horizontally and vertically, within 

the Olean. However, the formation usually consists 

of a thickly bedded, round or ·ovoid quartz pebble 

conglomerate, 15 to 28 m thick. It is strongly crossbedded, and the pebbles are white, milky, or rosecolored vein quartz, 10 to 90 mm in diameter. 

The type section of the Olean is at Rock City, 10 

km south of the city of Olean in southern Cattaraugus County, where its enlarged joints form the 

well-known "Olean Rock City." Elsewhere, the Olean 

is found in scattered hilltop exposures. Conspicuous 

ledges of the formation are seen because of its resistance to erosion. The formation appears to be of 

alluvial origin; plant remains of Pottsvillian age are 

the only fossils known to be indigenous to the Olean. 

In places, the conglomerate is at lower altitudes than 

the Knapp owing to the relief of the unconformity 

between them. 

Virtually nothing is known concerning the occurrence of a thin patch of dark, sandy, ferruginous 

shales once exposed overlying the Olean Conglomerate near Rock City. These shales have been referred to the Sharon Shale (Rogers, 1858) of Penn .. 

sylvania, but their thickness, extent, and fossil content in New York are unknown. 

There are no economic resources derived from the 

Carboniferous rocks of New York State. 

REFERENCES CITED 

Adams, R. W., 1970, Loyalhanna Limestone-cross-bedding 

and provenance, in Fisher, G. W., and others, eds., 

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Benson, F. M., 1934, The brachiopods of the Greenbrier 

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Berryhill, H. L., Jr., Schweinfurth, S. P., and Kent, B. H., 

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stratigraphic nomenclature for Upper Pennsylvanian 

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832 PENNSYLVANIA AND NEW YORK 

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Butts, Charles, 1903, Fossil faunas of the Olean quadrangle: 

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Caster, K. E., and others, 1935, Demise, of "Bradfordian 

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Chadwick, G. H., 1935, Faunal differentiation in the Upper 

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342. 

Chow, M. M., 1951, The Pennsylvanian Mill Creek limestone 

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Geology, v. 56, no. 4, p. 255-263. 

Darrah, W. C., 1969, A critical review of the upper Pennsylvanian floras of eastern United States with notes on 

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de Witt, Wallace, Jr., 1970, Age of Bedford Shale, Berea 

Sandstone, and Sunbury Shale in the Appalachian and 

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153-170. 

Donaldson, A. C., 1969, Ancient deltaic sedimentation (Pennsylvanian) and its control on the distribution, thickness, and quality of coals, in Some Appalachian coals 

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Field Trip 1969: Morgantown, W. Va., West Virginia 

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---1974, Pennsylvanian sedimentation of central Appalachians, 'l1n Briggs, Garrett, ed., Carboniferous of the 

southeastern United States: Geol. Soc. America Spec. 

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Durden, C. J ., 1969, Pennsylvania correlations using blattoid insects: Canadian Jour. Earth Sci., v. 6, no. 5, p. 

1159-1177. 

Edmunds, W. E., 1972, Coal reserves of Pennsylvania; total, 

recoverable, and strippable (January 1, 1970): Pennsylvania Geol. Survey, 4th ser., Inf. Circ. 72, 35 p. 

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resources of the southern half of the Penfield 15-minute 

quadrangle, Pennsylvania: Pennsylvania Geol. Survey, 

4th ser., Atlas 74cd, 184 p., 22 fold. maps. 

Ferm, J. C., 1974, Carboniferous environmental models in 

eastern United States and their significance, in Briggs, 

Garrett, ed., Carboniferous of the southeastern United 

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Ferm, J. C., and Cavaroc, V. V., Jr., 1969, A field guide to 

Allegheny deltaic deposits in the upper Ohio Valley, 

with a commentary on deltaic aspects of Carboniferous 

rocks in the northern Appalachian Plateau [1969 Spring 

Field trip]: [n.p.] Ohio Geol. Soc., and Pittsburgh, Pa., 

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Survey, 4th ser., County Rept. C56-A, 267 p. 

Fuller, J. 0., 1955, Source of Sharon Conglomerate of northeastern Ohio: Geol. Soc. America Bull., v. 66, no. 2, p. 

159-175. 

Glass, G. B., Edmunds, W. E., Shepps, V. C., Inners, J. D., 

and Sholes, M. A., 1977, Geology and mineral resources 

of the Ramey and Houtzdale quadrangles, Clearfield and 

Centre Counties, Pennsylvania: Pennsylvania Geol. Survey, 4th ser., Atlas 85cd, 94 p. 

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southwestern .New York: New York State Mus. Bull. 

69, p. 967-989. 

Gutschick, R. C., and Lamborn, Richard, 1975, Bifungites, 

trace fossils from Devonian-Mississippian rocks of 

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212. 

Haney, W. D., 1963, Stratigraphy of Greenbrier limesto·ne 

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Holland, F. D., Jr., 1958, The Brachiopoda of the Oswayo 

and Knapp Formations of the Penn-York embayment: 

Cincinnati, Ohio, Univ. Cincinnati, Ph.D. dissert., 524 

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12, pt. 2, p. 1619 (1959). 

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geologischen Vorzeit: Berlin, Gebriider Borntraeger, 255 

p. 

Laird, W. M., 1941, The Upper Devonian and Lower Mississippian of southwestern Pennsylvania: Pennsylvania 

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---1942, The stratigraphy of the Upper Devonian and 

Lower Mississippian of southwestern Pennsylvania: 

Cincinnati, Ohio, Univ, Cincinnati, unpub. Ph.D. thesis, 

244 p. 

Lesley, J. P., 1875, Notes on the comparative geology of 

northeastern Ohio, northwestern Pennsylvania, and 
THE MISS,JSSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 833 

western New York: Pennsylvania Geol. Survey, 2d, 

[v.] I, p. 57-108. 

---1879, Preface, in White, I. C., The geology of Lawrence 

County: Pennsylvania Geol. Survey, 2d [v.] QQ, p. ixxxxvi. ('See especially p. xx-xxi.) 

Lintz, Joseph, Jr., 1958, The fauna of the Ames and Brush 

Creek shales of the Conemaugh Formation of western 

Maryland: Jour. Paleontology, v. 32, no. 1, p. 97-112. 

Lund, Richard, 1970, Fossil fishes from southwestern Pennsylvania; Part I, Fishes from the Duquesne Limestones 

(Conemaugh, Pennsylvanian): Carnegie Mus. Annals, 

v. 41, no. 8, p. 231-261. 

Meckel, L. D., 1967, Origin of the Pottsville Conglomerates 

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Morris, D. A., 1967, Lower Conemaugh (Pennsylvanian) 

depositional· environments and paleogeography in the 

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Morris, R. W., Rollins, H.· B., and Shaak, G. D., 1973, A 

new ophiuroid from the Brush Creek Shale (Conemaugh 

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Murphy, J. L., 1970, Coiled nautiloid cephalopods from the 

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2, p. 195-205. 

Pelletier, B. R., 1958, Pocono paleocurrents in Pennsylvania 

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Pepper, J. F., de Witt, Wallace, Jr., and Demarest, D. F., 

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Raymond, P. E., 1911, A preliminary list of the fauna of 

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no. 2, p. 397-410. 

---1931, Pennsylvanian cycles in West Virginia: Illinois 

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Prof. Paper 602, 150 p. 
The Mississippian and Pennsylvanian 

(Carboniferous) Systems in the United StatesVirginia 

By KENNETH J. ENGLUND 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1110-C 

Prepared in cooperation with the 

Virginia Division of Mineral 

Resources 

Historical review and summary of areal, stratigraphic, 

structural, and economic geology of Mississippian 

and Pennsylvanian rocks in southwestern Virginia 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1979 

FIGURE 1. 

2. 

3. 

4. 

CONTENTS 

Abstract ----------------------------------------------------------------

Introduction ------------------------------------------------------------- Early investigatio:ls ______________________________ - ----------- _ ---- _-----

Present investigations ___________________________________ ---------- ____ -- _ 

Geologic setting _____________________________________ ---- __ ---- _ --- ____ --

Contact relations with underlying rocks -------------------------------

Contact relations with overlying rocks --------------------------------

Structural events during deposition.,-----------------------------------

Structural events following deposition --------------------------------

Stratigraphy ------------------------------------------------------------ Mississippian System _____________________________ -- __ ---- __ ----- _- --

Big Stone Gap Member of the Chattanooga Shale -----------------

Price Formation ______ -·-- ________ --------- ____ ------------------

Maccrady Shale -------------------------------------------------

Greenbrier Limestone -------------------------------------------- Bluefield Formation _________________________ ------ _____ ---------

Hinton Formation -----------------------------------------------

Princeton Sandstone --------------------------------------------- Mississippian and Pennsylvanian Systems ----------------------------

Bluestone Formation _________________ -------------------- ____ ---

Lee Formation --------------------------------------------------

Pennsylvanian System -----------------------------------------------

Pocahontas Formation -------------------------------------------

New River Formation ----.,..-------------------------------------- Norton Formation ______________________________________________ _ 

Gladeville Sandstone ---------------------------------------------

VVise Formation ------------------------------------------------- Harlan Formation _____________________________________________ _ 

Mississippian-Pennsylvanian boundary _______________________________ _ 

Facies changes ------------------------------------------------------ Depositional environments __________________ ------- _____________________ _ 

Igneous rocks -----------------------------------------------------------

Economic resources ------------------------------------------------------

Coal ----------------------------------------------.,.----------------- Natural gas and petroleum -------------------------------------------

Limestone ----------------------------------------------------------

Acknowledgments -------------------------------------------------------

References cited ---------------------------------------------------------

ILLUSTRATIONS 

Page 

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1 

1 

2 

3 

3 

3 

3 

4 

4 

4 

4 

5 

8 

8 

10 

10 

11 

11 

11 

14 

15 

15 

15 

16 

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16 

16 

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Map showing outcrop of the Mississippian and Pennsylvanian Systems in Virginia ---------------------

Index map of the southwestern Virginia coal field ----------------------------------------------------

Stratigraphic nomenclature used in southwestern Virginia -------------------------------------------

Stratigraphic cross section showing the relation of formations to the Mississippian-Pennsylvanian systemic 

boundary between the Cumberland Gap and Bramwell areas of the southwestern Virginia coal field __ 

III 

Page 

C2 

5 

6 

12 
rrHE MISSISSIPPIAN A·ND PENNSYLVANIAN (CARBONIFEROUS) SYSTEMS 

IN THE UNITED STATES-VIRGINIA 

By KENNETH J. ENGLUND 

ABSTRACT 

Carboniferous rocks in Virginia range f1·om Early Mississippian to Middle Pennsylvanian in age and consist mostly 

of inte1·bedded sandstone, siltstone, shale, li.mestone, claystone, and coal. These sedimentary deposits are assigned to 

15 formations, which underlie areas that total approximately 7,000 km~ in the Appalachian Plateaus and the 

Valley and Ridge physiogTaphic provinces in the southwestern part of the State. 

The sedimentation patterns and fossil content of the rock 

sequence have recorded fluctuations between marine and 

continental depositional environments in the east-central part 

of the Appalachian basin. In Mississippian time, marine 

events predominated during the deposition of a southeastward-thickeni~g sequence of mostly limestone, shale, and 

siltstone, which, to the east, includes lobes of barrier-bar and 

terrestrial coal-bea1·ing sediments. A repetition of marine 

and t~rrestrial environments p1·evailed until Early Pennsylvanian time, when a major seaward progradation of deltaic 

coal-bearing .sediments took place. Deposition was continuous 

across the systemic boundary in the trough area or eastern 

part of the Appalachian basin, whereas on the western limb 

of the basin, including westernmost Virginia, Upper Mississippian and Lower Pennsylvanian rocks were eroded sufficiently to form a hiatus between the Mississippian and 

Pennsylvanian Systems. The deposition of terrestrial coalbearing sediments continued throughout Early and Middle 

Pennsylvanian time with only an occ·asional marine transgression. Carboniferous rocks were folded and faulted by 

thrusting from the southeast during late or post-Paleozoic 

deformation. Consequently, sti·ata in the Appalachian 

Plateaus were gently folded and, in the Cuml?erland overthrust sheet, thrust about 6.4 km to the northwest. At the 

southeastern edge o~ the plateaus and in the Valley and 

Ridge province, Ca1 boniferous strata were highly folded 

and faulted. 

Coal, natural gas, and limestone are the principal mineral 

resources of economic interest in the Carboniferous rocks of 

Virginia. Coal of high-volatile A to low-volatile bituminous 

rank is the principal developed mineral resource. 

INTRODUCTION 

The Mississippian and Pennsylvanian Systems 

in Virginia are represented by approximately 5,100 

m of sedimentary rocks consisting of intercalated 

sandstone, siltstone, shale, claystone, limestone, and 

coal. The distribution of the rocks representing these 

systems is limited to the western part of the State, 

principally to the Appalachian Plateaus, and, to a 

lesser extent, to isolated areas of the adjoining Valley and Ridge province (fig. 1). Within the ·Appalachian Plateaus, strata are relatively flat and, except 

for sharply upturned beds near the southeastern 

edge, show only slight to moderate structural deformation. In contrast, correlative rocks of the Valley and Ridge province are found in several discontinuous and highly deformed fault slices that strike 

northeast across the west-central part of the State. 

Rocks of Missis~ippian age are the most widely distributed and include: (1) subsurface beds beneath 

Pennsylvanian r-ocks of the Appalachian Plateaus, 

(2) upturned beds at the southeastern edge of the 

plateaus, and (3) sporadic occurrences in the faulted 

and folded belt of the Valley and Ridge province. 

These rocks are largely of marine origin, but locally 

they grade into, and include, nearshore and terrestial 

deposits. Pennsylvanian rocks consist mostly of terrestial coal-bearing deposits that underlie the Appalachian Plateaus in the east-central part of the 

broad Appalachian coal basin and a few outliers in 

the faulted and folded belt. The latter areas are too 

small to show at the map scale. 

The stratigraphic nomenclature used in this paper 

has not been reviewed by the Geologic Names Committee of the U.S. Geological Survey. The nomenclature used here conforms with the current usage of 

the Virginia Division of Mineral Resources. 

EARLY INVESTIGATIONS 

Early investigations of the Mississippian and 

Pennsylvanian rocks of Virginia were made by Lesley ( 1873) , Stevenson ( 1881), Rogers (in MacFarlane, 1879), Boyd (1887), and McCreath and 

d'Invilliers (1888). These studies furnished preCl 
C2 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

EXPLANATION 

• Pennsylvanian 

System 

Mississippian 

System f',J 

Fault 

Contact 

( 

aoo/ 0~ 

380 ~·~----~--~~--+-------~~ ~ 

0 50 I I I I I I II II 1 I 

100 MILES 

I 

0 50 100 KILOMETERS 

FIGURE 1.-0utcrop of the Mississippian and Pennsylvanian Systems in Virginia. 

liminary assessments of the economic potential of 

various mineral occurrences and also provided the 

incentive for later comprehensive efforts to subdivide and map Carboniferous rocks (Campbell, 1893, 

1894a, 1896, 1897; Ashley and Glenn, 1906; Butts, 

1914; and Hinds, 1916). The nomenclature used by 

these workers differed from area to area, but by the 

early 1920's a relatively standardized set of subdivisions had been established in county and regional 

reports (Hinds, 1918; Harnsberger, 1919; Giles·, 

1921, 1925; Wentworth, 1922; Eby, 1923; and 

Campbell and others, 1925). Subsequent reports 

covered a broad range of stratigraphic studies, economic assessments, and geologic mapping that delineated occurrences of coal or natural gas in Carboniferous rocks (Butts, 1940, 1941; Averitt, 1941; 

Cooper, 1944; Wanless, 1946; Wilpolt and Marden, 

1949; Brown and others, 1952; Huddle and others, 

1956; Harris and Miller, 1958; Englund and Smith, 

1960; Englund, 1964a, h; LeVan, 1962; Read and 

Mamay, 1964; and Miller, 1965). Recent reports 

emphasize both geologic mapping and regional' 

stratigraphic studies (Englund and Delaney, 1966; 

Englund, 1968a, 1974; R~ L. Miller, 1969; M. S. 

Miller, 1974; Miller and Roen, 1971). 

PRESENT INVESTIGATIONS 

Current studies of rocks of Mississip·pian and 

Pennsylvanian age in Virginia are concerned principally with regional stratigraphy, resource assessments, and geologic mapping. To meet the need for 

a standard reference section for rocks of Pennsylvanian age, the establishment of a Pennsylvanian 

System stratotype was initiated in 1972 by the U.S. 

Geological Survey in consultation with interested 

geologists from State surveys, industry, and universities. For this study, a composite stratotype consisting of stratigraphically overlapping outcrop 

sections has been assembled with the support of 

paleontologic investigations, geologic mapping, and 

core drilling (Englund and others, 1977). These 

sections are located along a line between Tazewell 

County, Va., and the Dunkard basin in west-central 

West Virginia. 

The Virginia Division of Mineral Resources is cooperating with the U.S. Geological Survey in the collection of coal samples for analyses including ultimate and proximate, heat-content, free-swelling index, ash-fusibility, and major-, minor-, and traceelement determinations (Medlin and Goleman, 

1976). This study is contributing to a nationwide 
VIRGINIA C3 

program to assess the environmental and economic 

aspect of increased coal consumption including conversion processes, recoverable mineral by-products, 

and optimum utilization. 

Mississippian and Pennsylvanian rocks are also 

being mapped in several 7-lh minute quadrangles in 

Virginia for updating the assessment of the quantity and quality of coal resources (Miller and 

Meissner, 1978; Meissner and Miller, unpub. data; 

Englund and Warlow, unpub. data). In this study, 

coal beds are being mapped and sampled for information ·On the areal extent, thickness, chemical 

'composition, rank, ash and sulfur contents, and 

lateral changes in the coal deposits. Additional research concerning thickness and lithic variations in 

the roof and floor rocks, depositional controls and 

systems, and postdepositional structural features is 

being conducted to determine the effect of these 

geologic factors ·On the exploration and development 

of coal resources. 

GEOLOGIC SETTING 

CONTACT RELATIONS WITH UNDERLYING ROCKS 

In Virginia, Mississippian strata conformably 

overlie rocks of Late Devonian age. At Cumberland 

Gap, underlying strata consist of about 60 m of black 

shale assigned to the Chattanooga Shale of Late 

Devonian age. Northeastward, .this shale increases 

in thickness to about 244 m at Big Stone Gap, where 

it includes a middle merriber of gray siltstone 

(Miller, 1965). The upper or Big Stone Gap Member of the Chattanooga Shale is a black shale or 

siltstone that is partly Mississippian in age (Harris 

and Miller, 1958). 'Continuing northeastward along 

the outcrop belt at the southeastern edge of the 

Appalachian Plateaus, strata of Late Devonian age 

increase in ·thickness to about 610 m in northern 

Tazewell County, where they consist of the Brallier 

~hale, a medium- to dark-gray shale with lesser 

amounts ot interbedded siltstone and sandstone, and 

the Chemung Formation, a medium-light-gray very 

fine to fine-grained sandstone with minor amounts 

of greenish-gray shale. Only a few thin beds of 

black shale, typical of the Chattanooga Shale, are 

in these Upper Devonian rocks. In the northeasternmost expos·u'res of this outcrop belt, basal Mississippian strata consist of as much as 15m of black shale 

that correlates with the Big Stone Gap Member 

(Englund, 1968a). The discontinuous belt of Carboniferous rocks in the adjoining Valley and Ridge 

province also includes the Big Stone Gap Member 

at the base .of the Mississippian System. The underlying Upper Devonian strata are assigned to the 

Braillier Shale and the Chemung Formation (Bartlett and Webb, 1971). 

The age of Upper Devonian formations is based 

on conodonts (Roen, Miller, and Huddle, 1964) and 

brachiopods (Butts, 1940, p. 319-331; Cooper, 1944, 

p. 142; and Bartlett and Webb, 1971, p. 34-35). 

CONTACT RELATIONS WITH OVERLYING ROCKS 

The youngest Carboniferous rocks in Virginia are 

the Harlan Formation of Middle Pennsylvanian age. 

Only remnants of the formation are preserved on 

mountaintops in the southwesternmost part of the 

State where the upper contact is an erosional surface. Carboniferous rocks are not known elsewhere 

in Virginia where younger formation of Triassic, 

Cretaceous, and Tertiary age are present. In nearby 

areas of Kentucky and West Virginia, rocks equivalent to the Harlan Formation are conformably overlain by younger Pennsylvanian strata. 

STRUCTURAL EVENTS DURING THE DEPOSITION OF 

CARBONIFEROUS ROCKS 

The deposition of strata of Carboniferous age in 

the Appalachian basin ·took place during a period 

of slow subsidence as recorded by the shallow-water 

character of most of the sedimentary sequence. Subsidence was greatest along the eastern margin of 

the basin where the thickest sequence of strata accumulated. Deposition continued with only minor 

interruption throughout the Mississippian Period 

and into the early part of the Pennsylvanian Period. 

During deposition of the Mississippian strata, slight 

warping has been reported in nearby areas of West 

Virginia (Cooper, 1961, p. 95-99; Thomas, 1966) 

and along the Waverly arch in Kentucky (Englund, 

1972). However, such relationships are not readily 

evident in Virginia. · · 

Shortly after the deposition of the Pocahontas 

Formation in Early Pennsylvanian time, this southeastward-thickening wedge of Mississippian and 

Pennsylvanian rocks was uplifted, mostly where the 

western margin of deposition overlapped the eastern flank of the 'Cincinnati arch. Subsequent erosion 

truncated Lower Pennsylvanian strata including 

part of the New River Formation, the Pocahontas 

Formation, and Upper Mississippian strata, including several members in the upper part of the Bluedone Formation. Westward beyond the State, rocks 

of Late Mississippian age were completely eroded 

in places. 
C4 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

After the period of widespread erosion between 

the Mississippian and Pennsylvanian Systems, which 

was progressively greater toward the Cincinnati 

arch and along the crest of the Waverly arch, the 

deposition of Lower Pennsylvanian strata resumed. 

Again, the rate of deposition of coal-bearing strata 

in the Lower and Middle Pennsylvanian Series approximated the rate of subsidence, which was greatest along the eastern margin of the basin. 

STRUCTURAL EVENTS FOLLOWING DEPOSITION 

At the end of Carboniferous sedimentation, a 

southeastward-thickening. wedge of sediments extended from the Cincinnati arch southeast across 

southwestern Virginia and into the trough of the 

Appalachian geosyncline. The youngest sediments of 

Middle Pennsylvanian age were virtually flat lying 

after their deposition. Perhaps an additional 300 m 

or more of Pennsylvanian sediments accumulated in 

Virginia and have since been eroded. During the 

Appalachian orogeny, possibly as early as Late 

Pennsylvanian or Early Permian time, mountainbui'lding stresses were projected northwest with sufficient intensity to affect Carboniferous rocks 

throughout southwestern Virginia. Consequently, 

the present attitude of Carboniferous rocks reflects 

both the regional downwarping of the Appalachian 

geosyncline and structural deformation associated 

with postdepositional faulting. 

Structurally, the areas underlain by Carboniferous 

rocks are divided by faulting into three distinct segments: (1) relatively flat lying rocks of 1

the Appalachian Plateaus northeast of the Cumberland 

overthrust sheet, (2) gently folded and faulted rocks 

of the Cumberland overthrust sheet, and (3) intensely folded and faulted rocks of the Valley and 

Ridge province. In the area of relatively flat lying 

rocks of the Appalachian Plateaus, Car,boniferous 

rocks dip mostly 1 o to 2°. Locally, ·along gentle 

northe,ast-trending flexures, the dip increases to as 

much as 5o. At the southeastern edge of the area, 

beds are near vertical or slightly overturned. 

Rocks of the Cumberland overthrust sheet have 

moved about 6.4 km northwestward (Englund, 

1971) and are warped into two broad folds-the 

Middlesboro syncline and the Powell Valley anticline. In Virginia, this thrust sheet is bounded on 

the northeast by the Russell Fork fault and in the 

subsurface by the Pine Mountain overthrust fault. 

Strata in the trough of the Middlesboro syncline are 

gently warped but may dip as much as 5° on the 

fringes of the trough area. The syncline is outlined 

by resistant Lower Pennsylvanian conglomeratic 

sandstone, which dips from a few degrees to nearly 

vertical along Cumberland Mountain and from 20° 

to 30° along Pine Mountain on the southeast and 

northwest limbs, respectively. The Powell Valley 

anticline parallels the Middlesboro syncline and 

plunges northeastward beneath Carboniferous rocks, 

which dip from a few degrees to vertical or slightly 

overturned (fig. 2) . _ 

In the areas of intensely folded and faulted rocks, 

Carboniferous rocks are almost entirely Mississippian in a.ge, are found in fault slices as much as 5 

km wide and 170 km long, and generally dip from 

0° to 50°. 

STRATIGRAPHY 

Carboniferous rocks in Virginia range in age from 

Early Mississippian to Middle Pennsylvanian and 

are of marine and terrestrial sedimentary origin. Of 

this sequence, the lower 2,500 m are assigned to 

eight formations of Mississippian age and the upper 

2,600 m, to seven formations of Pennsylvanian age 

(fig. 3) 0 

MISSISSIPPIAN SYSTEM 

BIG STONE GAP MEMBER OF THE 

CHATTANOOGA SHALE 

The Big Stone Gap Member (Stose, 1923) of Late 

Devonian and Early Mississippian age includes basal 

Carboniferous strata in most of southwestern Virginia. In the type area, Big Stone Gap, Va., it consists of black evenly bedded shale and siltstone as 

much as 80 m thick. Northeastward, the member 

thins to 3 m or less in the Bramwell area, and southwest of Big Stone Gap, it merges with the underlying part of the Chattanooga Shale, which is entirely Devonian in age at Cumberland Gap. In the type 

section, the member contains both Early Mississippian and Late Devonian conodont faunas. The lowest 

definitely Mississippian conodont fauna is found 

about 28 m above the base and is characterized by 

Siphonodella, which is present throughout the upper 

part of the member. The following species have been 

identified (Roen and others, 1964) : 

Elictognathus lacerata (Branson and Mehl) 

Polygnathus communis (Branson and Mehl) 

inornatus (E. R. Branson) 

Pseudopolygnathus sp. 

Siphonodella duplicata (Branson and Mehl) 

quadruplicata (Branson and Mehl) 

Spathognathodus aciedentatus (E. R. Branson) 
Coalfia~f 

0 10 20 30 40 50 KILOMETERS I I I I I I 

VIRGINIA 

TAZEWELL 

...,_ .. 

,...-·-t,S\ 

, '\ .. ~"" , " ' 

..... ../ -~ ' ~-·- \ ' ,/ , SMYTH 

\ .. ...> ' '\ ,./ \ / .. / WASHINGTON , "') _ _..,.-

/

,/ SCOTT \ V' GRAYSON 

LEE VIRGINIA \ · -----~' ----~a;-'~------' ---------TENNEssEE---------' ,r-------

FIGURE 2.-lndex map of the southwestern Virginia coal field (shaded). 

C5 

PRICE FORMATION 

The Price Formation (Campbell, 1894b) of Early 

Mississippian age is also known as the Grainger 

Formation in southwesternmost Virginia, where it 

includes the basal Mississippian strata. Elsewhere 

in Virginia, the formation conformably overlies the 

Big Stone Gap· Member of the Chattanooga Shale. 

The Price consists largely of light-gray very fine to 

medium-grained sandstone· and light-gray to greenish-gray shale, silty shale, and siltstone. Grayish-red 

beds also are present locally. Eastward in the Valley 

and Ridge province, the formation coarsens and includes feldspathic sandstone and well-rounded 

quartz pebbles and granules. Several glauconite beds 

have been recognized (Bartlett and Webb, 1971, p. 

36) , and coal beds have been locally noted in the 

formation (Campbell and others, 1925). 

Marine fossils are abundant locally in the Price 

Formation and include the following forms (Bartlett and Webb, 1971, p. 36) : 

As much as 6 m of cherty dolomite, a wedge of 

the Fort Payne Chert, is at the top. of the Price 

Formation at Cumberland Gap (Englund, 1964b). 

In the northeastern outcrops of Mississippian rocks, 

strata equivalent to the Price consist of coarsegrained conglomeratic sandstone assigned to the 

Pocono Formation, which overlies the Hampshire 

Formation of Devonian age. The thickness of the 

Price Formation increases northeastward from 90 

m at Cumberland Gap to more than 500 m in the 

faulted and folded belt. 

Brachiopods : 

Cama'rotoech£a sp. 

Chonetes sp. 

shumardanus De Koninck 

Dictyoclostus burlingtonensis (Hall) 

Punctospirifer sp. 

Reticularia pseudolineata (Hall) 

Schellwienella? sp. 

Schuche'rtella desiderata Hall and Clark 

Spi'rifer cf. S. stratiformis Meek 

· winchelli? Herrick 

Tete'racamera '! sp. 

Tm·ynifer cf. T. pseudolineata (Hall) 

Bryozoans: 

Cystodictya sp. 

F enestrellina regalis? (Ulrich) 

tenax (Ulrich) 

Polypora impressa? (Ulrich) 

Rhombopo'ra sp. 

Pelecypods : 

Allm·isma? sp. 

A viculopecten? sp. 

Solemya? sp. 
C6 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

CUMBERLAND GAP AREA 

Ashley and 

Glenn (1906) 

Englund and others 

(1961) Englund(1964a) 

~;~-fiff&i11fci Hignite Formation a. Hignite Formatiort" 

::::J 

Catron Formation e Catron Formation (!) 

1---------1 i:: 

Mingo Formation £ Mingo Formation 

~--------------~~ Hance Formation aJ Hance Formation 

Naese Sandstone 

Member 

Naese Sandstone 

Member 

Bee Rock 

Sandstone Member 

Hensley Member 

BIG STONE GAP AREA 

Campbell (1893) Miller (1965) Miller 

and Roen (1971) 

~::;j.·.'·:.'·~r--""<··:.·:.·:._.:.:·:.:·:.'·;.'·:.'~ 

Harlan Sandstone Harlan Formation 

Wise Formation 

Gladeville Sandstone > Norton Formation 

Bee Rock 

Wise Formation 

Gladev•le Sandstone 

Norton Formation 

Bee Rock 

Sandstone 

Member 

------------~~------~c c: 

0 

c: 

0 

E 

0 

u.. 

Q) 

Q) 

_, 

Pennington Shale 

c: 

0 

E 

Middlesboro 

Member 

0 

co 

E 

0 

u.. 

Q) 

Q) 

_, 

co 

E 

0 

u.. 

Q) 

Q) 

_, 

0 

u.. 

.:D:.::a.:.::rk:...:.R.:.:;id~:l!lr..::e...:;M:.:.:e::.:m..:.:b:.::e:....r -i~-o::::-....:liil=l:lf----------------....j.....---"""'....,..........,~ ~ --~. White Rocks 5 Nl 

Sandstone 

~ 

Member 

Chadwell Member [) 

~ ember g 

Lower Member '§ 

Q) 

0... 

~ ~ Upper Member 

eB 

~ ~ 

Z

Q) .§ 

_, Lower Member 

Pennington Shale 

Newman Limestone 

Q, 

::::J 

0 

Bluestone 

(!) Formation 

c 

0 

Cl 

c 

c: 

c 

~ P~r~in-ce-to_n_S_a_n_d_s-to-n ..... ~ 

c: Little Stone Gao Member 

E ·~Middle Red Member .!: E 

:z: .f Stony Gap Sandstone Mbr. 

Bluefield Formation 

Greenbrier Limestone 

Newman Limestone Fort Payne Chert ~ Maccrady Shale 

- __::::s 

Grainger Formation Grainger Shale Price Formation 

Big Stone Gap 

SW. VIRGINIA 

Miller (1974) 

Wise Formation 

Gladeville Sandstone 

Norton Formation 

Quartz Arenite c: Upper a> 

Member .~ 

c 

0 

-co 

E 

0 

co Midd;;>l u.. E Quartz Arenite 

~ Membe ~ u.. > 

Q) 

Q) 

a: 

-' Low~r ~ Quartz Arenite z Member 

- ~c;;,ontas jiJY ___!~rmation 

IJ ~c:::;;;..-4---- c: 

0 

·.;::; 

§ 

0 

u.. 

Q) 

c: 

~ Q)---------t ii5 Pride Shale Member 

Princeton Interval 

c: Little Stone Gap Member 

:§·g 

... ca .!: E 

:z: ~ -S-t-on_y_G-ap_S_a-nd-st-on_e_M_b-fr. 

Bluefield Formation 

Greenbrier Limestone 

~----------------r---~-----------+--------r----------------;-----?-------? --~----------------------------- Chattanooga Chattanooga Member of 

Shale Shale Chattanooga Shale Chattanooga Shale 

FIGURE 3.-Stratigraphic nomenclature used in southwestern Virginia; vertical lines indicate strata missing. 
-

-

TAZEWELL COUNTY 

Harnsberger (1919) 

Norton Formation 

Lee Formation 

Bluestone Formation 

c:: 

0 

·~ 

Cooper (1944) 

Lee Formation 

Bent Mountain Member 

Hunt Member 

E Bratton Sandstone Member 

&£ Belcher Member 

Mud Fork Member 

Glady Fork Sandstone Mbr. 

Picestem Shale Member 

Pride Shale Member 

Princeton Sandstone Princeton Sandstone 

c 

0 

·.;:::; 

cu 

E 

0 

u.. Hinton Formation c Falls Mils Sandstone Mbr. 

B 

Bluefield Shale 

~ Avis Limestone Member 

·c: 

c 

Q) 

0... Stony Gap Sandstone Mbr. 

Bluefield Shale 

"Gasoer'" limestone 

··ste. Genevieve'" limestone 

Newman Limestone 1--..;.;H.;.;.ill~sd:..:a...;.la_L_im_e_st_on_e __ -1 

little Valley Formation 

Grainger Shale 

Maccrady Formation 

Price Formation 

Big Stone Gap Shale 

"Chemung" 

Formation 

VIRGINIA 

BRAMWELL AREA 

Sandstone 

Bee Rock~ ......:. 

Member 

Hensley) 

.g Member) 

c 

0 

·.;:::; 

cu 

E 

0 cu 

E 

~ Middlesboro Q) 

u.. 

~ Member 

c 

0 

·.;:::; 

cu 

E 

0 

u.. 

I~ B 

C/) 

Q) 

::J 

a5 

Lll" -

ocahontas 

ormation 

-~pp~r~ 

Memoer~ 

Bramwell Member 

Red Member 

Gray Member 

Glady Fork 

Sandstone Member 

Pride Shale 

Member 

Princeton Sandstone 

Upper Shale Member 

c Falls M~ls Sandstone Mbr. 

·.8 Pratter Shale Member E Tallery Sandstone Member 

0 Middle Shale Member 

u.. Neal Sandstone Member 

5 little Stone Gao Member 

E :f Hackett Sandstone Member 

Stony Gap Sandstone Mbr. 

Indian Mils 

Sandstone Member 

Greenbrier Limestone 

Maccrady Shale 

Price Formation 

Big Stone Gap Member 

of Chattanooaa Shale 

Chemung Formation 

FIGURE 3.-Continued. 

THIS REPORT 

sw. NE. 

~:::::::::~~~~:::::::~~~ 

Harlan Formation 

Wise Formation 

Gladeville Sandstone 

Norton Formation 

B~ Sandstone c 

0 

Member .... 

cu 

Hensley E 

.._ 

Membe 0 

u.. 

.._ 

Q) 

Middlesboro > 

a:: 

Member ~ Q) 

c z 0 

~ 

cu 

E 

~·= rmation 

u.. 

0 ~ 

White Roc 

Sandstone 

Membe Q) Bluestone 

Q) 

__. Formation 

Chadwell 

Member ~-s 

c 

0 

·.;:::; 

Pinnacle cu 

Overlook E 

0 Member u.. 

_......,..ittle Stone Gail Mbr. g 

Stonvg E 

Sandstone :I: 

Member 

Bluefield Formation 

Greenbrier Limestone 

Maccrady Shale 

Price Formation 

Big Stone Gap Member 

of Chattanooaa Shale 

Chemung Formation 

~ 

w 

1-

(/) 

>- (/) 

z 

~ 

z 

<{ 

> 

__. 

>-

(/) 

z 

z 

w 

0... 

z 

~ 0... 

0... 

(/) 

(/) 

(/) 

~ 

~ 

1-

(/) .~(/) w oz!:!:! a: 

w ~i=ffi (/) z(/) 

8 

c 

cu 

.:.e. 

0 

:i Q) 

=o 1--

1J 

~ 

1--

c 

cu 

~ 

e 

0 

Q) ~ 

~ 

__. 0 

c 

Q) cu 

a. "! a. C/) 

::> Q) 

,$;. 

u 

1---

1-- Meramecian 

z 

~(/) a..!:!:! 

oa:: a::W ::>(/) 

w 

c 

.!!! 

iii 

,$;. 

a. 

1i) 

Q) 

3: 

c 

cu 

·;: 

::J 

E 

cu 

z 

c 

cu 

Q) 

C/) 

5 

~ Osagean -"J,-- 0 -~ c 

__. Kinder- :; .!!! 

hookian g __ 

DEVONIAN 

C7 
C8 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Gastropods : 

Euphemites galericulatus (Winchell) 

Oxydiscus sp. 

Correlative beds in nearby areas of Tennessee 

contain the following faunas of Early Mississippian 

age, most likely Osagean (Englund, 1968b, p. 9) : 

Corals: 

Cyathaxonia sp. indet. 

A mplexizaphrentis sp. undet. 

Trochophyllum verneuili Milne Edwards 

and Haime 

"Zaphrentoid" corals 

Cladochonus amplexus (Rowley) 

Bryozoans: 

Fenestella sp. indet. 

Sajj01·dotaxis cf. S. incrassatus (Ulrich) 

Cystodictya sp. undet. 

Brachiopods: 

Schuchertella sp. 

Chonetes aff. C. glenparkens1:s Weller 

sp. 

Small spinoise productoid 

Strophalosia? sp. 

Productina sampsoni (Weller)? 

Labriproductus? sp. 

Rhynchonellid indet. 

Punctospirifer subellipticus (McChesney) 

Strophopleura sp. 

Spirifer aff. S. shephardi Weller 

aff. S. vernonensis Weller 

Spirifer or Branchythris sp. indet. 

Crurithyris cf. C. parva (Weller) 

Pelecypods : 

Cypricardinia sp. 

Gastropods : 

Platyceras sp. 

Echinoderms: 

Crinoid stems and plates 

Batocrinoid anal tube 

Echinoid plate 

Trilobites: 

Phillibole cf. P. conkini Hessler 

Proetides? sp. indet. 

Ostracodes : 

Bairdia sp. 

Graphiadactyllis lineata (Bassler) 

Graphidactyllis? sp. 

MACCRADY SHALE 

The Maccrady Shale (Stose, 1913) of Early Mississippian age is a distinctive grayish-red to brightred shale including minor amounts of sandstone, silistone, or very finely crystalline dolomitic limestone. 

It attains a maximum thickness of about 45 m in the 

. Bramwell area, thins southwestward, and is absent 

at Cumberland Gap. Thinning has resulted from 

truncation at the disconformable base of the overlying Greenbrier Limestone. Fossils, consisting of 

small assemblages of bryozoans and brachiopods of 

Osagean age, are sparse in the Maccrady Shale 

(Butts, 1940, p. 353; Cooper, 1944,. p. 153). 

GREENBRIER LIMESTONE 

In southwestern Virginia, the Greenbrier Limestone (W. B. Rogers, in Macfarlane, 1879) of Late 

Mississippian age has been identified as part of the 

Newman Limestone (Campbell, 1893, p. 38) or has 

been divided into the Warsaw Formation and the St. 

Louis, Ste. Genevieve, and Gasper Limestones by 

Butts (1940, p. 355-381) or the Little Valley Formation and the Hillsdale, "Ste. Genevieve," and 

"Gasper" Limestones by Cooper (1944, p. 154-169). 

The Greenbrier consists mostly of thick-bedded very 

finely to coarsely crystalline limestone that is light 

olive gray and, l~s commonly, medium gray and 

brownish gray. It also includes oolitic, cherty, and 

yellowish-gray weathering argillaceous limestone 

beds and a few interbeds of greenish-gray or grayish-red shale. It extends throughout most of the 

area underlain by Carboniferous rocks and ranges 

from a minimum thickness of about 80 m at Cumberland Gap to about 335 m in the Bramwell area. 

A maximum thickness of about 900 m is found in 

the faulted and folded belt. Marine faunas of Late 

Mississippian age are present in nearly all beds of 

the Greenbrier Limestone. The following fossils 

were collected from basal beds assigned to the Little 

Valley Formation by Cooper (1944, p. 156-157) : 

Protozoan: 

Endothy1·a sp. 

Coral: 

T1·iplophyllum compressum (Edwards and 

Haime) 

Blastoid: 

Pentremites conoideus Hall 

Bryozoans: 

Fenest?·alia sancti-ludovici (Prout) 

F enestrellina serratula (Ulrich) 

tenax (Ulrich) 

Fistulipora sp. 

Stenopora sp. 

Worthenopora spinosa (Ulrich) 
VIRGINIA C9 

Brachiopods : 

Cama'rotoechia cf. C. g1·osvenor·i (Hall) 

mutata (Hall) 

Cliothy1·idina sp. 

Echinoconchus biseriatus (Hall) 

01·thotete.~ lcaskaslciensis (McChesney) 

P1·oductus cf. P. altonensis Norwood and 

Pratten 

·indianiensis Hall 

tenuicostus Hall ·, 

Retic'itla1·ia sa.lemensis Weller 

~pi'l·ife?· bi/u1·catus Hall 

St?·ept01··hynchus 'I'Uginos'wn (Hall) 

Pelecypod: 

A viculopecten am plus Meek and Worthen 

The lower middle part of the Greenbrier, assigned 

to the Hillsdale Formation, has yielded the following 

forms (Cooper, 1944, p. 159) : 

Algae: 

"Gi1·anvella" sp. 

Corals: 

LUhost1·otionella "canadensis" ( Gastlenau) 

p?·oli/e?·a (Hall) 

Sy1·ingopo1·a V1:1·ginica Butts 

Bryozoans: 

Dichot1·ypa sp. 

FenestTellfna tenax (Ulrich) 

!l emit1·ypa p1·outana Ulrich 

Polypo1·a bisertiata Ulrich 

Stenop01·a, sp. 

Brachiopods : 

B1·achythy1is altonensis Weller 

Cliothy1·idina sublamellosa (Hall) 

Dielasma sp. 

01·thotete.~ lcaskaskiens·is (McChesney) 

Productus ovatus Hall 

gallatinensis Beede 

tenuicostus Hall 

Spi'l·ife?· delicatus Rowley 

cf. S. pellaensis Weller 

Gastropod: 

Bellm·ophon cf. B. sublaevis Hall 

The following fossils were collected from the 

upper middle part ("Ste. Genevieve" equivalent) of 

the Greenbrier Limestone (Cooper, 1944, p. 163-

164) : 

Corals: 

Menophyllum p1·incetonensis (Ulrich) 

Sy'l'?:ngopora sp. 

Triplophyllum spinulosum (Edwards and 

Haime) 

Blastoids: 

Pent1·emites princetonensis Ulrich 

buttsi Ulrich 

pulchellus Ulrich 

Crinoid: 

Platyc1·inUes huntsvillae Safford 

Bryozoans: 

Batostomella inte1·stincta Ulrich 

Fistulip01·a pecuUaTis Rominger 

Lioclemella sp. 

Brachiopods : 

Athyris dens a Hall 

CUothy1·idina cf. C. parvirost1'is (Meek 

and Worthen) 

hi1·suta (Hall) 

sublamellosa (Hall) 

Dielasma sp. 

Echinoconchus genevievensis Weller 

Gi1·tyella indianensis ( Girty) 

P1·oductus·ovatus Hall 

infiatus McChesney 

pa1·vus Meek and Worthen 

Spin:ferina sp. 

Spi?·ifer pellaensis Weller 

Fossils in the upper part, ("Gasper" equivalent) 

of the Greenbrier include (Cooper, 1944, p. 168) : 

Corals: 

Campophyllum gasperense Butts 

Triplophyllum spinulosum (Edwards and 

Haime) 

Blastoids: 

Pent1·emites "go doni" Ulrich 

py'l·ifo'l·mi.~ Say 

sp. 

ce1·vinus Hall 

patei Ulrich 

Crinoids: 

Agassizoc1·inus sp. 

cf. A. conicus Wachsmuth and 

Springer 

Platyc1·inites sp. (stem plates not spinose) 

Pte?·otoc?·inus serratus Weller 

spatulatus Wether by 

Tala1·ocrinus infiatus Ulrich 

ovatus Worthen 

Bryozoans: 

A Tchimedes proutanus Ulrich 

sp. 

Cystodictya sp. 

Brachiopods : 

Chonetes cf. C. chesterensis Weller 

Cliothyridina sublamellosa (Hall) 
C10 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED S'rATES 

Composita tr·inuclea (Hall) 

Diaphr·agmus elegans (Norwood and 

Pratten) 

Echinoconchus sp. 

Eumetria verneuilana (Hall) 

Orthotetes cf. 0. kaskaskiensis 

(McChesney) 

Spirifer leidyi Norwood and Pratten 

Spiriferina cf. S .. fJpinosa (Norwood and 

Pratten) 

BLUEFIELD FORMATION 

The Bluefield Formation (Campbell, 1896) of Late 

Mississippian age is also identified in southwestern 

Virginia as the upper member of the Newman Limestone. It conformably overlies the Greenbrier Limestone and consists mostly of medium- to mediumdark-gray, greenish-gray, and grayish-red partly 

calcareous shale. Interbedded limestone and argillaceous limestone is fine crystalline to medium 

crystalline and light olive gray to medium gray. 

Locally, the formation includes beds of siltstone or 

fine-grained sandstone as much as 24 m thick. Also, 

a few thin coal beds associated with underclay and 

carbonaceous shale ·are present in places. The Blu·efield Formation increases in thickness eastward from 

about 90 m at Cumberland Gap to 365 m in the 

Bramwell area. It is found throughout the area of 

Carboniferous rocks in southwestern Virginia, except for a few localities where only lower Mississippian rocks are preserved. 

The Bluefield is abundantly fossiliferous, particularly the limestone and calcareous shale beds in 

the lower part of the formation. The forms listed 

below indicate that the Bluefield is correlative with 

the Glen Dean Limestone and possibly the Golconda 

Limes,tone of the midcontinent region (Cooper, 1944, 

p.171-172): 

Blastoids: 

Pentremites brevis Ulrich 

maccalliei Schuchert 

Crinoid: 

Pterotocrinus spatulatus Wether by 

Bryozoans: 

Archimedes communis Ulrich 

sp. 

Fenestrellina cf. F. tenax (Ulrich) 

Fistulipora sp. 

Polypora sp. 

Septopora subquadrans Ulrich 

Stenopora sp. 

Brachiopods : 

Camarophm·ia explanata (McChesney) 

Cliothyridina sublamellosa (Hall) 

Diaphragmus elegans (Norwood and 

Pratten) 

Eumetria verneuilana (Hall) 

Orthotetes cf. 0. kaskaskiensis 

(McChesney) 

Productus cf. P. in/latus :McChesney 

Reticularia setigera (Hall) 

SpiTifer cf. S. incr·ebescens Hall 

cf. S. transversa (McChesney) 

Pelecypods : 

A viculopecten sp. 

Edmonia sp. 

Myalina sp. 

Sphenotus sp. 

HINTON FORMATION 

The Hinton Formation (Campbell and Mendenhall, 1896) of Late Mississippian age is characterized by abundant grayish-red partly calcareous 

shale and siltstone, but it also includes several intercalated sandstone beds, minor amounts of medium-gray and greenish-gray shale, fossiliferous 

limestone and calcareous shale, and a few thin beds 

of coal or carbonaceous shale underlain by rooted 

underclay. It conformably overlies and locally intertongues with the Bluefield Formation. Southwestward from Big Stone Gap, correlative strata have 

been included in the Pennington Formation or 

Group. 

The Stony Gap Sandstone Member at the base of 

the Hinton is commonly quartzose, highly resistant, 

ripple bedded and as much as 30 m thick. It consists of white to very light-gray, very fine to medium-grained sandstone, which locally splits into 

two or more beds with greenish-gray or grayish-red 

shale intervening. Well-rounded pebbles and cobbles 

also are found in the member at a few localities. In 

places, the member grades to micaceous ripplebedded sandstone that contains a relatively small 

amount of quartz. 

The thickest and most widespread of several 

marine beds in the Hinton Formation is ~the Little 

Stone Gap Mem:ber (Miller, 1964) or Avis Limestone of Reger ( 1926). It is found as much as 185 

m above the Stony Gap .Standstone Member in the 

Bramwell area but converges southwestward to 

within 25 m of the top. of the Stony Gap Sanstone 

Member near Cum·berland Gap. The Little Stone 

Gap Member consists of medium-gray limestone, 
VIRGINIA C11 

argillaceous limestone, and calcareous shale that 

totals as much as 23 m in thickness. Marine fossils, 

including brachiopods, pelecypods, bryozoans, and 

gastropods of Chesterian age are common in the 

mem:ber. 

The Tallery Sandstone Member is the most prominent and widely distributed of several sandstone 

units in the upper part of the Hinton Formation. It 

is white to light gray, very fine to medium. grained, 

thick bedded to massive, and, in most places, quartzose. It commonly contains well-rounded quartz 

pebbles and, for this reason, has been misidentified 

as the stratigraphically higher Princeton Sandstone 

(fig. 4) 0 

The Tallery Sandstone Member ranges from 0 to 

50 m in thickness and is split locally into two or 

more beds separated by medium-gray or greenishgray shale. 

The total thickness of the Hinton Formation 

ranges from a minimum of 50 m at Cumberland 

Gap to as much as 395 m in the Bramwell area. 

PRINCETON SANDSTONE 

The lithically distinctive Princeton Sandstone 

(Campbell and Mendenhall, 1896) of Late Mississippian age conformably overlies the Hinton Formation. It has been described as a polymictic conglomerate or as a coarse conglomeratic subgraywacke 

(Cooper, 1961, p. 69) and consists mainly of lightgray, fine- to coarse-grained, thick-bedded to massive 

calcite-cemented sandstone. Clasts in the formation 

are highly diverse in composition, size, and abundance and are composed of well-rounded to angular 

fragments of quartz, shale, siltstone, limestone, 

chert, and ironstone. The Princeton Sandstone attains a maximum thickness of about 18 m in the 

Bramwell area. Southwestward it becomes thinner, 

less conglomeratic, and grades to a very fine grained 

ripple-bedded sandstone before wedging out at the 

base of the Pride Shale Member of the overlying 

Bluestone Formation in west-central Tazewell 

County, Va. Fossils in the Princeton are largely 

limited to reworked specimens in limestone clasts. 

MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS 

BLUESTONE FORMATION 

The youngest Mississippian strata in Virginia are 

included in the Bluestone Formation (Campbell, 

1896), which consists of six widely recognized members. The Bluestone attains a maximum thickness of 

a:bout 250 ·m in Tazewell County, Va .. 

The Pride Shale Member (Reger, 1926), at the 

base of the formation, is a dark-gray evenly bedded 

shale that grades locally to silty shale or to interlaminated siltstone and shale. Basal beds of the 

member may include partly calcareous greenishgray and grayish-red shale. Pyrite and ironstone 

nodules and lenses as much as 1.3 em thick are 

com.mon in the dark-gray shale. A characteristic 

feature of the member is a grooved or fluted vertical 

surface in relatively fresh or slightly weathered 

exposures. From a maximum thickness of about 80 

m in the Bramwell area, the Pride Shale thins 

southwestward and is not differentiated southwest 

of Big Stone Gap. Marine and ~brackish-water fossils 

are found locally in the mem·ber. 

The Glady Fork Sandstone Member (Reger, 1926) 

varies in composition from silty ripple-bedded sandstone to coarse conglomeratic subgraywacke. The 

sandstone is light gray, fine to coarse grained, and 

thin bedded to massive. Well-rounded to angular 

clasts in the member are composed of quartz, shale, 

siltstone, limestone, chert, and ironstone. The Glady 

Fork sandstone is found only in Tazewell County 

where it ranges from 0 to 18m in thickness. 

The gray member of the Bluestone Formation is 

a wedge of interbedded medium-gray shale, lightgray sandstone, siltstone, argillaceous limestone, and 

a few thin beds of coal and associated underclay. It 

is restricted to Tazewell County, where it attains a 

maximum thickness of 60 m, and, where the Gladys 

Fork Sandstone wedges out, the gray member 

merges southwestward with the Pride Shale Member. Fresh- or brackish-water ostracodes and pelecypods are found in several beds o.f carbonaceous 

shale. A flora, dominated by Stigmaria stellata is 

found in several beds of the member (Gillespie and 

Pfefferkorn, 1977). 

The red member of the Bluestone Formation is 

largely grayish-red, partly calcareous shale, siltstone, and sandstone. Lesser amounts of greenishgray to medium-gray shale, siltstone, sandstone, 

argillaceous limestone, rooted underclay, coal, and 

carbonaceous shale are also present. The member is 

as much as 100m thick in the Bramwell area, thins 

southwestward, and wedges out in the Big Stone 

Gap area. Ostracodes and Lingula are common in 

carbonaceous shale beds. 

The Bramwell Member (Englund, 1968a), the 

uppermost unit of Mississippian age in the Bluestone Formation, is predominantly medium-gray to 

medium-dark-gray shale that coarsens upward and 

locally grades from very fine to fine-grained ripplebedded sandstone. A persistent basal bed of black 

carbonaceous shale contains abundant ostracodes, 

pelecypods, and Lingula; overlying beds of the 
C12 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

CUMBERLAND GAP 

AREA 

SOUTHWEST 

- -----:-----------

EXPLANATION 

r7l 

l:.:.:..J 

Sandstone, Sandstone, Sandstone, 

conglomeratic, quaruose conglomeratic 

quaruose 

r.:1 u 

Sandstone, 

rippl~-bedded 

Sandstone Limestone 

~ 

~ Limestone and calcareous shale 

.D 

Shale, interbedded with 

siltstone, sandstone,· 

coal,underclay, and/ or limestone 

FIGURE 4.-Stratigraphic cross sec,tion showing the relation of formations to the Mississippian-Pennylvanian 

systemic boundary between the Cumberland Gap and Bramwell areas of the southwestern Virginia coal 

field. Line of section shown in figure 2. 
r ~ 

Lower Pennsylvanian 

Upper Mississippian 

Pride Shale Member 

Bluefield Formation 

METERS 100 L

OOFEET 

50 

0 MILES 

0 . 5 10 KILOMETERS 

VIRGINIA 

BRAMWELL AREA 

NORTHEAST 

. . . . . . . . ~· .. . . · .. · .. ·. : .. : :: ....... ': . 

Pocahontas Formation 

Stony Gap Sandstone 

Member 

FIGURE 4.-Continued. 

c 

0 

c 

x 

C13 
C14 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

member contain articulate brachipods and pelecypods. Ellipsoidal argillaceous limestone concretions, 

15-50 em in diameter, are found locally. In Virginia, 

the member is limited to Tazewell County, where it 

ranges. from 16 to 36 m in thickness. The following 

assemblages of Late Mississippian age were ·collected 

from a marine faunule in the Bramwell Member 

(Englund, 1974, p. 34). 

USGS 22500-PC 

Fenestella sp. 

Polypo'ra? sp. 

Lingula sp. 

Orbiculoidea sp. indet. 

Orthotetes cf. 0. kaskaskiensis ( M·cChesney) 

Diaphragmus cf. D. cestriensis (McChesney) 

Ovatia sp. 

Anthracospirifer leidyi (Norwood and Pratten) 

Eumetria cf. E. vera (Hall) 

Polidevcia sp. 

Paleyoldia sp. indet. 

Aviculopecten sp. (approaching Limipecten) 

Posidonia? sp. indet. 

Solenomya sp. 

Sphenotus sp. indet. 

Wilkingia? sp. 

Edmondia sp. 

Composita subquadrata (Hall) 

Knightites (Retispira) sp. 

USGS 22754-PC 

Lingula sp. 

Orbiculoidea? sp. indet. 

Orthotetes aff. 0. kaskaskiensis (McChesney) 

Diaphragmus cf. D. cestriensis 

Ovatia cf 0. elongata Muir-Wood and Cooper 

Anthracospirifer leidyi (Norwood and Pratten) 

Composita subquadrata (Hall) 

sp. 

Eumetria cf. E. vera Hall 

Beecheria cf. B. whitfieldi ('Girty) 

Schizodus sp. 

Cypricardella? sp. 

Sphenotus sp. indet. 

Bellerophontid gastropod, indet. 

Trilobite pygidium (fragment) 

The upper member of the Bluestone Formation 

consists principally of slightly calcareous shale and 

siltstone that show the typical grayish-red and 

greenish-gray colors of the Bluestone Formation. 

A persistent bed of light-greenish-gray sparsely 

rooted ·claystone and scattered ironstone spherules 

is at the ·top of the member. The member intertongues and grades laterally with the lower sandstone mem·ber of the Pocahontas Formation of Early 

Pennslyvanian age. For this reason and because of 

the presence of N europteris pocahontas, a Lower 

Pennsylvanian fossil, the upper member is classified 

a~ Pennsylvanian in age. The member ranges from 

0 to 24 m in thickness and merges westward with 

the red member of the Bluestone Formation. 

LEE FORMATION 

The Lee Formation (Campbell, 1893) of Late Mississippian and Early Pennsylvanian age has been 

divided in the type area, Lee County, Va., into seven 

mapped members, which are, in ascending order: 

Pinnacle Overlook, Chadwell, White Rocks Sandstone, Dark Ridge, Middlesboro, Hensley, and Bee 

Rock Sandstone Members (Englund, 1964a). The 

Late Mississippian members-Pinnacle Overlook, 

Chadwell, and White Rocks Sandstone Membersare quartzose sandstone and conglomeratic sandstone lobes that total as much as 135m in thickness, 

and intertongue with the Bluestone or Pennington 

Formation. Basal Pennsylvanian beds consist of 

dark-gray shale, fine-grained sandstone, coal, and 

underclay which constitute the Dark Ridge Member, 

a correlative of the Pocahontas Formation. The 

Middlesboro Member disconformably overlies the 

Dark Ridge Member, Pocahontas Formation, or the 

Bluestone Formation. It is the most prominent and 

extensive member of the Lee Formation, es·pecially 

in the Cumberland Gap and Big Stone Gap areas, 

where it consists of four locally coalescing quartzose 

and conglomeratic sandstone tongues that total as 

much as 150m in thickness. Northeastward, the proportion of nonresistant strata in the member increases, a relationship that is accompanied by a 

divergence and splitting of the quartzose ·conglomeratic tongues (fig. 4). The lower and upper tongues 

of the member were designated lower and middle 

quartz arenite members orf the Lee Formation by 

Miller ( 197 4, p. 63). 

The Hensley Member of the Lee Formation is a 

sequence of nonresistant sandstone, siltstone, shale, 

coal, and underclay as ·much as 122 m thick. Where 

the Bee Rock Sandstone Member tongues. out, strata 

equivalent to the Hensley Member are -included , in 

the Norton Formation (fig. 4). 

The Bee Rock Sandstone Member, the uppermost 

unit of the Lee Formation in Virginia, consists of 

two lobes of quartzose conglomeratic sandstone that 

are as much as 90 m thick. It grades at its northeastern fringe to nonresistant feldspathic sandstone 

of the Norton Formation. 
VIRGINIA C15 

The seven members of the Lee Formation aggregate 485 m in thickness.. Plant fossils are found 

throughout the Lee Formation, and the floras are 

similar to thos·e listed for the New River and Pocahontas Formations. Fresh- and brackish-water invertebrate faunas are also present. 

PENNSYLVANIAN SYSTEM 

POCAHONTAS FORMATION 

The Pocahontas Formation (Campbell, 1896) is 

a northwestward-thinning wedge of coal-bearing 

clastic rocks that underlies an area of about 9,000 

km:: at the southeastern edge of· the Appalachian 

coal field. It conformably overlies the Bluestone 

Formation, and, in contrast to the variegated and 

calcareous beds of that formation, the Pocahontas 

consists of interbedded light- to dark-gray sandstone, siltstone, shale, coal, and underclay. Of these, 

sandstone is most abundant and constitutes about 

70 percent of the formation; siltstone, shale, and 

underclay total 28 percent; and coal, the remaining 

2 percent. Outcrops in Virginia are limited to a 

narrow discontinuous belt of upturned beds at the 

southeastern edge of the coal field (fig. 2) . From a 

maximum thickness of about 299 m in the outcrop 

area, the formation thins northwestward for about 

48 km to where it wedges out in the subsurface at an 

average depth of about 450 m below the principal 

valley floors. 

Fresh- or brackish-water pelecypods and Lingula 

are present in several beds; plant fossils, including 

stems, leaves, and roots, are found throughout the 

formation. The flora is characterized by an abundance of New·opte'ris pocahontas, and other reported 

forms are as follows (Pfefferkorn and Gillespie, 

1977) : 

L11ginopte·ris sp. 

M esocalamites sp. 

Ma'riopte,.ris pottsvillea White 

Calamites sp. 

Palmatopteris furcata (Brongniart) H. Potonie 

Asteroph11lUtes charaeformis Sternberg 

N e'wropte'ris smithsii Lesquereux 

NEW RIVER FORMATION 

The Pocahontas Formation is conforma:bly overlain by the New River Formation of Early Pennsylvanian age in most outcrop areas. This conforma:ble 

contact, placed at the base of the Pocahontas No. 8 

coal bed, extends northwestward for several kilometers .to where the upper beds of the Pocahontas 

Formation are truncated by the unconformity at the 

base of the Pineville Sandstone Member of the New 

River Formation or the correlative Middlesboro 

Member of the Lee Formation. Northwest of the 

area underlain by .the Pocahontas Formation, upper 

beds of the Bluestone Formation were also eroded 

away, and there the disconformity at the base of 

the New River coincides with the widespread Mississippian-Pennsylvanian unconformity (Englund, 

1969). In addition, a hiatus is substantiated by the 

absence of floral zone 4 of Read and Mamay (1964). 

The New River Formation (Fontaine, 1874)" is 

widely recognized in West Virginia, but in Virginia 

it is limited to parts of Buchanan and Tazewell 

Counties where the laterally equivalent Lee Formation has tongued out. The New River ranges from 

about 425 to 520 m in thickness and is a coal-bearing sequence of sandstone, siltstone, shale, and underclay. Lithically, it is similar to the Pocahontas 

Formation except for the presence of thicker and 

more widespread beds of quartz-pebble conglomerate 

or congomeratic sandstone. To the .southwest and 

west, these coarse clastic rocks grade to quartzose 

conglomeratic sandstone of the Lee Formation 

(Englund and Delaney, 1966). Sandstone in the New 

River Formation is typically light gray, fine to 

coarse grained, thin to . thick bedded, and locally 

massive. In addition to quartz, which ranges from 

45 to. 65 percent, the sandstone contains a notable 

amount of white-weathering feldspar, mica, and 

carbonaceous grains. Fossil plants are abundant in 

the formation, including the following forms, which 

were identified in conjunction with the Pennsylvaian System stratotype study in near-by areas of 

West Virginia (Pfefferkorn and Gillespie, 1977) : 

Calamites sp. 

Aster·ophyllites cha?·aefoTmis Sternberg 

Lyginopteris sp. 

M aTiopteTis pottsvillea White 

Alethopteris decurrens Artis 

Sphenophyllum cumeifolium ( Stern1berg) Zeiller 

Fresh- or brackish-water faunules are found in 

several beds of the New River Formation. A marine 

assemblage collected from a calcareous shale overlying the Pocahontas No. 8 coal bed in Buchanan 

and Tazewell Counties (Henry and Gordon, 1977) 

includes: 

Rugose coral, gen. and sp. indet. 

Small pelecypods indet. 

Pelmatozoan columnals 

Paleyoldia? sp. 

Lingu,la carbonaria McChesney 

Schizodus? sp. indet. 
C16 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Orbiculoidea sp. indet. (fragment) 

Bellerophontacean, gen. and s.p. indet. 

Small marginiferid productoid? 

Straparollus (Euomphalus?) sp. indet. 

Composita sp. indet. 

Pleurotomaracean ·gen. and sp. indet. 

Nuculopsis cf. N. girtyi Schenck 

Palaeosolen sp. 

Phestia sp. 

Fish scales 

NORTON FORMATION 

The Norton Formation (Campbell, 1893) of Early 

and Middle Pennsylvanian age is composed mostly 

of medium- to. dark-gray shale and siltstone and 

lesser amounts of fine- to medium-grained sandstone, 

coal, and underclay. In contrast to the quartzose 

conglomeratic sandstone typical of the Lee Formation, that of the Norton tends to be finer grained, 

feldspathic, and micaceous, and has a relatively low 

quartz content of 50 to 60 percent. In most areas, 

the Norton Formation conformably overlies the Lee 

Forrriation; however, where the Lee is absent along 

the Virginia-West Virginia State line, correlative 

beds are assigned to the Kanawha Formation, which 

overlies the New River Formation. The thickness of 

the Norton increases northeastward fro·m a minimum of 165 m to as much as 600 m. Fossil plants, 

including stems, leaves, and roots, are found 

throughout the formation. Several carbonaceous 

shale beds contain fresh- or brackish-water pelecypods and Lingula. 

GLADEVILLE SANDSTONE 

The Gladeville Sandstone (Campbell, 1893) is a 

widely recognized resistant unit that conformably 

overlies the Norton Formation. In the type area, 

Miller (1969) described the formation as a massive, 

strongly cross1bedded medium-grained quartzose: 

sandstone about 15.5 m thick. Regionally, the Glad~ 

ville grades to fine-grained feldspathic micaceous 

sandstone that is nonresistant and possibly absent 

in places. 

WISE FORMATION 

The Wise Formation (Campbell, 1893) of Middle 

Pennsylvanian age is an important ooal-·bearing 

sequence in the southwestern Virginia coal field. It 

conformably overlies the Gladeville Sandstone and, 

in addition to coal, consists of sandstone, siltstone, 

shale, underclay, and limestone. The sandstone is 

light gray, fine to medium grained, thin bedded to 

massive, micaceous, feldspathic, and contains about 

· 50-60 percent quartz. Several sandstone members, 

including the Robbins Chapel, Keokee, Clover Fork, 

and Reynolds Sandstone Members are as much as 30 

m thick (Miller, 1969, p. 25-30). The shale and siltstone are mostly medium to dark gray, but beds of 

black cal"bonaceous shale and calcareous shale are 

also present. Two widesp·read marine units in the 

formation-Kendrick Shale of Jillson ( 1919) and 

the Magoffin Beds of Morse ( 1931) -consist of 

limestone, calcareous shale, or siltstone that contains abundant brachiopods and pelecypods. Fossil 

plants are abundant in many shale and siltstone 

beds. The Wise Formation averages about 580 m in 

thickness. 

HARLAN FORMATION 

The Harlan Formation (Campbell, 1893) of Middle Pennsylvanian age conformably overlies the. Wise 

Formation and includes the youngest Carboniferous 

rocks in Virginia. Sandstone is the dominant lithology; it ranges from fine to coarse grained, light 

to medium light gray, and feldspathic to quartzose. 

At the base of the formation the sandstone is massive, cliff forming, and occupies channels that truncate underlying beds. Siltstone, shale, and several 

coals and associated underclay are present in overlying :beds. The Harlan Formation attains a maximum thickness of about 200 m in the highest mountaintops along the Virginia-Kentucky State line. 

Plant fossils are fo_und throughout the formulation. 

MISSISSIPPIAN-PENNSYLVANIAN BOUNDARY 

The boundary between the Mississippian and 

Pennsylvanian Systems in Virginia has been placed, 

by definition and on the basis of paleontologic data, 

at the contact between the Bluestone and Pocahontas 

Formations. This long-standing practice has continued in recent studies in the southeasternmost outcrops where the .Pocahontas attains its maximum 

thickness of about 213 m. However, a modification 

of this relationship, the systemic boundary exto the northwest of the lower .sandstone mem·ber of 

the basal tongue of the Pocahontas Formation in 

the upper part of the Bluestone Formation. Because 

of this relationship, the systematic ·boundary extends from the base of that sandstone member into 

the upper part of the Bluestone Formation at approximately the contact between the Bramwell Member and the upper mem·ber (fig. 4). About 48 km 

northwest of the outcrop area, the unconformity at 

the base of the Pineville Sandstone Member of the 
VIRGINIA C17 

New River Formation, or the Middlesboro Member 

of the Lee Formation, truncates the Pocahontas 

Formation and the upper part of the Bluestone 

Formation. Thus, the depositional continuity of beds 

across the systemic boundary is replaced to the 

northwest by a widely recognized hiatus. Maximum 

truncation of Mississippian beds. takes place near 

the Virginia-Kentucky State line, where the Middlesboro Member disconformably overlies the Pride 

Shale Member of the Bluestone Fomation. 

FACIES CHANGES 

The facies in the Carboniferous rocks of Virginia 

are representative of various continental and marine 

depositional environments. For example, the Lower 

Mississippian Price Formation and its correlatives 

consist of greenish-gray shale and siltstone containing marine fossils in the Cum,berland Gap area 

and westward. In the easternmost outcrops of the 

faulted and folded belt, this part of the stratigraphic 

section is a coarse clastic terrestrial coal-bearing 

sequence. Similarly, a largely marine facies of fine 

clastic rocks in the Bluestone Fo·rmation of the 

Bramwell area is represented to the southwest by 

nearshore deposits of coarse orthoquartzite that 

dominate the Lee Formation in the Cumberland 

Gap area. The latter rock type in overlying beds of 

the Lee also intertongues and grades laterally with 

coal-bearing paludal and fluvial facies of the Norton 

and New River Formations, which are characterized 

by feldspathic subgraywacke sandstones. An idealized facies relationship between marine and continental rocks is also shown by marine shale in the 

Bluestone Formation and clean-washed bar sandstone, alluvial distributary sandstone, and coaJ-bearing paludal deposits in the Pocahontas Formation, 

which are found in lateral sequence southeastward 

across the southwestern Virginia coal field (Englund, 1974). 

D.EPOSITIONAL ENVIRONMENTS 

Patterns of sedimentation in the Carboniferous 

rocks of Virginia record the fluctuations of marine 

and continental environments in a shallow, slowly 

subsiding basin. Southwestern Virginia was inundated by a shallow marine sea during the initial 

deposition of Early Mississippian sediments in the 

Big Stone Gap Member of the Chattanooga Shale. 

A detailed study of the lithically similar Chattanooga Shale in Tennessee by Conant and Swanson 

(1961, p. 60-62) concluded on the basis of paleontologic and sedimentologic data that deposition was 

in a shallow-water marine environment. The overlying Price Formation recorded the first seaward 

progradation of terrestrial sediments during Mississippian time in Virginia. Beds of coal and carbonaceous shale intercalated with fluvial sandstone 

indicate that deposition took place in broad coastal 

swamps that were periodically cros~d by fluvial 

distributaries, while marine deposition continued 

to the west in the correlative Grainger Shale o.f the 

Cumberland Gap area. 

Extensive marine transgression is again evident 

in the overlying Maccrady Shale, which may represent nearshore tidal deposits that were uplif.ted 

and eroded slightly prior to the onlap of subtidal 

to supratidal clastic and nonelastic Greenbrier sediments. Marine organisms flourished during deposition of the Greenbrier, and the fragmental condition 

of the fossils indicates a nearshore or tidal environment of deposition. A seaward encroachment o.f 

nearshore mud and sand and brief periods of marine 

transgression are recorded in the overlying Bluefield Formation. At times, brackish- or fresh-water 

swamps .supported vegetation growth and peat ~ccumulation. The Stoney Gap Sandstone Member at 

the base of the Hinton Formation records a convergence of offshore bars, as indicated by sandstone distribution patterns, by the clean, well-washed, and 

well-sorted character of the sand, and by the occurrence of marine limestone beds a few meters above 

and below the member. A repetition of terrestrial 

and marine environments continued throughout the 

deposition of the Hinton Formation, as shown by the 

local occurrences of coal, lagoonal shale, bar sandstone, and limestone.· 

The deposition of the Princeton Sandstone suggests a high-energy prograding shoreline where wellrounded quartz and chert pebbles were transported 

by longshore and tidal currents together with locally 

derived limestone clasts. Miller (1974, p. 109) proposed a quiet-water lagoonal environment, directly 

behind beach-barrier bars for the origin of the overlying Pride Shale Member, which contains both 

brackish-water and marine faunas. The Glady Fork 

Sandstone Member represents the intertidal redistribution of sand and gravel by current and wave 

action which preceded the seaward p-rogradation of 

terrestrial sediments of the gray member of the 

Bluestone. The red member of the Bluestone contains thin nodular limestone of a supratidal environment as well as tidal-creek channels. The drowning 

of the coastal plain on which the red member was 

deposited took place during the deposition of marine 

sediments of the Bramwell Member of the Bluestone. 
C18 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Deposition of the Pocahontas Formation began 

with a coarse clastic wedge building seaward over 

marine sediments and intertonguing with the prodeltaic mud of the upper member of the Bluestone 

Formation. Thickness and lithic variations in this 

clastic wedge demonstrate that sand deposition was 

concentrated in several merging delta lobes and was · 

interspersed with quartz-pebble gravel along some of 

the main distributaries. The orientation of these 

delta lobes indicates a general northwest progradation of sediments originating from the southeast. 

During deposition of the upper part of the basal 

sand wedge, a decrease in the influx of sand was accompanied by southeastward encroachment by mud 

over areas of relatively thin sand, mostly in the 

interlobe areas. The main distributaries continued 

to disperse sand at a reduced rate but in sufficient 

quantities to permit intertonguing on a small scale 

with mud during the final phase of sand deposition. 

Deposition of the silt and mud was followed by 

accumulation of peat, as recorded by coal as much 

as 1.2 m thick over the sand lobes. The concentration of peat on abandoned lobes may have been due 

to the greater compactibility of mud in the interlobe 

areas, resulting in lagoons with water too deep for 

optimum growth of vegetation. 

Marine regression to the northwest resumed during deposition of the middle and upper parts of the 

Pocahontas Formation, which consist of several delta lobes stacked above those of the lower unit. The 

superposition of lobes over lower ones indicates that 

the sediments were transported generally along the 

same drainage lines that existed previously. During 

the deposition of these beds, the shoreline stabilized 

sufficiently for the formation of a barrier bar of 

clean well-washed sand. The location of the thickest 

part of the bar just beyond a large centrally located 

lobe suggests that distributaries of this lobe were 

the principal source of s~nd. At the distal edges of 

the lobe, the sand was subject to reworking and winnowing by waves and longshore currents, possibly 

from the northeast, as indicat~d by a gradual southwestward thinning of the bar away from distributaries of the principal lobe. Continued regression 

during the deposition of the Pocahontas was accompanied by a northwestward growth of alluvial distributaries over and beyond the barrier bar. Swamp 

deposits are more extensive up·ward in the sequence 

and consist of silt, mud, and peat that accumulated 

over abandoned sublobes and, to a lesser extent, in 

interlobe areas. The widespread occurrence of peat 

may have been related to shoreline stability as well 

as to a minimum influx of sediments. Incursion of 

clastic materials decreased abruptly, and widespread 

swamp conditions prevailed during deposition of the 

Pocahontas No. 3 coal bed. 

After the deposition of the Pocahontas Formation, 

much of the area was inundated by a transgressing 

sea, and marine muds were deposited locally above 

the Pocahontas No. 8 coal bed. Shortly thereafter, 

the northwestern edge of the formation was uplifted and extensively eroded. Truncation of the 

Pocahontas Formation and beds in the upper part of 

the underlying Bluestone Formation was followed 

by the deposition of the overlying New River and 

Lee Formations in environments dominated by 

coastal and near-coastal deltaic processes. Sedimentation was similar in many respects to that of the 

Pocahontas Formation, except for the formation of 

more widespread and thicker barrier bars of clean 

well-washed sand. 

The Norton Formation, which intertongues with 

the Lee Formation in Virginia, represents back-barrier, lagoonal, and lower delta-plain environments 

where coal beds are relatively thin and discontinuous. Landward from the deposits, the coal beds are 

thicker and more widespread, and intervening sandstones occupy channels characteristic of the upper 

delta plain. A similar relationship· is recorded upward in the N ortori and overlying formations, except for the Wise and Harlan Formations which also 

contain fluvial sandstones that occupy deeply incised channels of an alluvial plain. Therefore, the 

environmental sequence extends laterally as well as 

upward from the Lee Formation, from back-barrier, 

through lower and upper delta-plain, to an alluvialplain environment. 

IGNEOUS ROCKS 

Igneous activity during the deposition of Carboniferous rocks in Virginia is suggested by the occurrence of sanidine in a bentonite bed associated with 

a coal bed of uncertain correlation in the Wise 

Formation (Nelson, 1959). Sanidine also occurs in 

a flint clay bed in the Fire ·clay coal of Kentucky 

(Seiders, 1965), a correlative of the Wallins Creen 

coal bed of the Wise Formation. These occurrences, 

which may represent the same bed, have been attributed to a volcanic origin. 

ECONOMIC RESOURCES 

COAL 

Bituminous coal is the principal developed mineral resource in rocks of Carboniferous age in Vir-
VIRGINIA C19 

g1n1a. Commercial mining, which began in the late 

1880's in the southwestern Virginia coal field has 

depleted extensive areas of the most accessible highquality coal. Most production has come from underground mines, including both large mines that have 

facilities for rail shipment and many small mines 

that use truck haulage. Large-scale surface mining 

began in the 1940's and now accounts for 30 percent of total production, mostly from narrow contour strips on mountain slopes which locally are accompanied by auger mining. A record amount of 36 

million metric tons of coal was mined from underground and surface operations in 1976 (Virginia 

Dept. of Labor and Industry, 1977). 

Small-scale mining of semianthracite, which began in the early 1900's in the Valley coal fields of 

the faulted and folded belt, attained a maximum 

annual production of about 247,000 metric tons in 

1926 (Bro-wn and others, 1952, p. 39). Commercial 

mining of this coal was inactive in 1976. 

Coal in the southwestern Virginia coal field consists of common banded varieties that range in rank 

from high-volatile A to low-volatile bituminous. 

Mined coal beds commonly have a high free-swelling 

index (Nos. 5-9), a low to medium sulfur content 

(0.5 to 2.0 percent), a high heat value ( 13,500 to 

14,900 Btu), and a low ash content (2 to 9 percent). 

Because of its excellent coking properties, the coal 

is in demand by both the domestic and foreign markets. A comparison of the trace-element content of 

Virginia coal beds with those of other areas shows 

essentially the same or much lower concentration 

(Medlin and Goleman, 1976). Available analyses of 

semianthracite from the Valley coal field indicate 

that the coal is mostly lo·w in sulfur content (0.3 to 

1.2 percent), moderately high in ash (12.8 to 28.4), 

and moderately high in heat value ( 10,530 to 

12,890 Btu) (U.S. Bureau of Mines, 1944). 

Coal is found in nine ·formations of Cavboniferous 

age in Virginia and in at least 120 beds, of which 

55 are of economic importance. The Pocahontas, 

New River, Norton, and Wise Formations contain 

most of the coal resources and mining development. 

The distribution of individual coal beds ranges from 

those a few square kilometers in area to widespread 

beds that extend throughout much of the southwestern Virginia coal field. Coal bed thicknesses 

range from less than 1 em to as much as 5 m, 

but more commonly from 1 to 1.5 m in mining areas. 

Coal beds of Cavboniferous age contain a total 

remaining identified resource of 8,662 million metric 

tons (Averitt, 1975, p. 15). Of this total, about 47 

percent is in thin heds (85-70 em thick), about 35 

percent in intermediate beds (70-105 em thick), 

and about 18 percent in thick beds (more than 105 

em thick) (Brown and others, 1952). Recent investigations have indicated the presence of an additional 4,.535 million metric tons of undiscovered 

resources. 

NATURAL GAS AND PETROLEUM 

Natural gas has been produced commercially from 

Carboniferous rocks in Virginia since 1938. Initial 

pr·oduction was from sandy zones in the Little Valley 

Limestone, equivalent to part of the Greenbrier 

Limestone, of the Early Grove gas field in the Ridge 

and Valley area of Scott County (Averitt, 1941). 

The first commercial gas well in the Appalachian 

Plateau of Virginia was completed in 1948 in sandstone of Late Mississippian age (LeVan, 1962). Gas 

production is currently from the Price Formation, 

Greenbrier Limestone, and the Hinton Formation. 

Nearly 7,000,000 Mcf of gas was· produced from 

180 wells in 1976 from Mississippian and Devonian 

rocks (Lytle and others, 1977). Rocks of Carboniferous age lack petroleum production, but shows of 

oil have been reported at several horizons in these 

strata. 

LIMESTONE 

The Greenbrier Limestone .has been the principal 

source of crushed stone in rocks of Carboniferous 

age. It has been quarried at several localities for 

roadstone and concrete aggregate. 

ACKNOWLEDGMENTS 

The wri.ter is grateful for the fieldwork collaboration and contributions of his research associates, 

particularly R. L. Miller, C. R. Meissner, Jr., J. F. 

Windolph, Jr., and R. C. Warlow. Reviews by G. 

H. Wood, Jr., T. W. Henry, and P. C. Lyons provided many critical and helpful suggestions. The cooperation of the Virginia Division of Mineral Resources is sincerely appreciated 

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C20 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

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---1964b, Geology of the Middlesboro South quadrangle, 

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Quad. Map GQ-301. 

---1968a, Geologic map of the Bramwell quadrangle, West 

Virginia-Virginia: U.S. Geol. Survey Geol. Quad. Map 

GQ-745. 

---1968b, Geology and coal resources of the Elk Valley 

area, Tennessee and Kentucky: U.S. Geol. Survey Prof. 

Paper 572, 59 p. 

---1969, Relation of the Pocahontas Formation to the 

Mississippian-Pennsylvanian systemic boundary in southwestern Virginia and southern West Virginia [abs.]: 

Geol. Soc. America Abs. with Programs, [v.1], pt. 4, 

p. 21. 

---1971, Displacement of the Pocahontas Formation by 

the Russell Fork fault, southwest Virginia: U.S. Geol. 

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---1972, Central Appalachian tectonics as indicated by 

structural features in Carboniferous rocks [abs.]: Am. 

Assoc. Petroleum Geologists Bull., v. 56, no. 10, p. 2108. 

---1974, Sandstone distribution patterns in the Pocahontas Formation of southwest Virginia and southern 

West Virginia: Geol. Soc. America Spec·. Paper 148, 

p. 31-45. 

Englund, K. J., Arndt, H. H., Gillespie, W. H., Henry, T. W., 

and Pfefferkorn, H. W., 1977, A field guide to ·proposed 

Pennsylvanian System stratotype, West Virginia: American Assoc. Petroleum Geologists/Society Econ. Paleontologists and Mineralogists, Ann. Convention, Wasfiington, D.C., June 1977, 80 p. 

Englund, K. J., and DeLaney, A. 0., 1966, Intertonguing relations of the Lee Formation in southwestern Virginia: 

U.S. Geol. Survey Prof. Paper 550-D, D47-D52. 

Englund, K. J., and Smith, H. L., 1960 Intertonguing and 

lateral gradation between the Pennington and Lee formations in the Tri-State area of Kentucky, Tennessee, 

and Virginia [abs.]: Geol. Soc. America Bull., v. 71, 

no. 12, p. 2015. 

Englund, K. J., Smith, H. L., Harris, L. D., and Stephens, 

J. G., 1961, Geology of the Ewing quadrangle, Kentucky 

and Virginia: U.S. Geol. Survey Geol. Quad. Map 

GQ-172. 

Fontaine, W. M., 1874, The "Great Conglomerate" on New 

River, West Virginia: Am. Jour. Sci., 3d, v. 7, p. 

459-465, 573-579. 

Giles, A. W., 1921, The geology and coal resources of Dickenson County, Virginia: Virginia Geol. Survey Bull. 21, 

224 p. 

---1925, The geology and coal resources of the coal-bearing portion of Lee County, Virginia: Virginia Geol. 

Survey Bull. 26, p. 1-177. 

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and biostratigraphy at the Mississippian-Pennsylvanian 

boundary ·in the Pennsylvanian System stratotype area, 

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Ser. 154, p. 41. 

Harnsberger, T. K., 1919, The geology and coal resources 

of the coal-bearing portion of Tazewell County, Virginia: Virginia Geol. Survey Bull. 19, 195 p. 

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Map GQ-111. 

Henry, T. W., and Gordon, Mackenzie, Jr., 1977, Late Missippian and Pennsylvanian faunas in area of proposed 

Pennsylvanian System stratotype in Englund and others. 

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Geologists/Society of Econ. Paleontogists and Mineralogists, Ann. Convention, Washington, D.C., June, 1977, 

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· Bull. 12, 206 p. 

---1918, The geology and coal resources of Buchanan 

County, Virginia: Virginia Geol. Survey Bull. 18, 250 p. 
VIRGINIA C21 

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2, p. 96-104. 

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of the Big A Mountain quadrangle, Russell and Buchanan Counties, Virginia: U.S. Geol. Survey Geol. 

Quad. Map GQ-1350. 

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24, p. 22-62. 

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473-494. 

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and eastern Kentucky: U.S. Geol. Survey Oil and Gas 

Inv. (Prelim.) Chart 38, 3 sheets, text. 
The Mississippian and Pennsylvanian 

(Carboniferous) Systems in the United StatesWest Virginia and Maryland 

By THOMAS ARKLE, JR., DENNIS R. BEISSEL, RICHARD . 

E. LARESE, EDWARD B. NUHFER, DOUGLAS G. PATCHEN, 

RICHARD A. SMOSNA, WILLIAM H .. GILLESPIE, RICHARD 

LUND, C. WARREN NORl'ON, and HERMAN W. PFEFFERKORN 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1110-D 

Prepared in cooperation with the 

West Virginia Geological and Economic Survey 

and theM aryl and Geological Survey 

Historical review and summary of area, stratigraphic, 

structural, and economic geology of Mississippian, 

Pennsylvanian, and Lower Permian rocks in West Virginia 

and adjacent parts of Maryland 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1979 

CONTENTS 

Page 

Jlbstract ----------------------------------------------------------------- D1 

Introduction ------------------------------------------------------------- 1 

Acknowledgments ---------------------------------------------------- 1 

Early geologic work ------------------------------------------------------ 3 

Physiography ------------------------------------------------------------ 4 

Structure ---------------------------------------------------------------- 6 

~ineral resources -------------------------------------------------------- 7 

Coal ---------------------------------------------------------------- 8 

Oil and natural gas --------------------------------------------------- 9 

Construction and industrial minerals ----------------------------------- 10 

Iron ore ------------------------------------------------------------- 11 

Ground water -------------------------------------------------------- 11 ~iss·issippian System --------------------------------------------- 11 

Pennsylvanian and Permian Systems ------------------------------- 11 

~ississippian System ----------------------------------------------------- 12 

Lithostratigraphy ---------------------------------------------------- 12 

Systemic boundaries ---------------------------------------------- 13 

Tectonic influence on sedimentation -------------------------------- 14 

Pocono Formation ------------------------------------------------ 14 

ldaccrady Formation ---------------------------------------------- 15 

Greenbrier Group ------------------------------------------------ 15 

~auch Chunk Group ---------------------------------------------- 16 

Biostratigraphy and paleontology -------------------------------------- 17 

Invertebrate ----------------------------------------------------- 17 

Vertebrate ------------------------------------------------------- 17 

Paleobotany ------------------------------------------------------ 18 

History·of study --------------------------------------------- 18 ~ississippian .flora _________________________ -------------- ___ _ 18 

Pennsylvanian and Permian Systems -------------------------------------- 19 

Lithostratigraphy ---------------------------------------------------- 19 

Older mining district --------------------------------------------- 19 

Pocahontas Formation -------------------~-------------------- 21 

New River Formation ---------------------------------------- 23 

Kanawha Formation and Charleston Sandstone Group ---------- 23 

Younger mining district ------------------------------------------ 24 

Pottsville Group ---------------------------------------------- 24 

Allegheny Formation ----------------------------------------- 25 

Conemaugh Group -------------------------------------------- 27 ~onongahela Group ------------------------------------------ 27 

Dunkard Group ---------------------------------------------- 28 

Biostratigraphy and paleontology ------------------------------------- 28 

Invertebrate ----------------------------------------------------- 28 

Vertebrate ------------------------------------------------------- 29 

Paleobotany ------------------------------------------------------ 30 

References cited --------------------------------------------------------- 31 

ILLUSTRATIONS 

FIGURE 1. Correlation chart showing late Paleozoic classification ---------------------------------------..;:::.--..... -- , 

2. Geologic map of the late Paleozoic of West Virginia and ~aryland --------------------------'\l'~...: ... ·-.. 'J':·· 4 

m 
IV 

FIGURE 3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

11. 

12. 

CONTENTS 

Physiographic map of West Virginia and adjacent Maryland --------------------------------------

Structural map of the late Paleozoic of West Virginia and Maryland -------------------------------

Map showing late Paleozoic mineral resources of West Virginia and Maryland -----------------------

Map showing outcrop of the Mississippian and type sections in West Virginia and Maryland --------

Cross section of Mississippian strata along outcrop belt --------------------------------------------

Map showing basin trends and coal-mining features of Pennsylvanian-Permian strata in West Virginia 

and Maryland ------------------------------------------------------------------------------ Geologic cross section from the Ohio River to Princeton, W. Va ------------------------------------

Chart showing rthe Pennsylvanian System selective classification-older mining district (southern West 

Virginia)---------------------------------------------------------------~--------------------

Cross sections showing rock assemblages of the younger mining district -------------------------~-­

Chart showing the Pennsylvanian and Permian Systems selective classification-younger mining district (northern West Virginia and Maryland)-------------------------------------------------

Page 

D5 

6 

8 

13 

14 

20 

21 

22 

25 

26 
THE MISSISSIPPIAN AND PENNSYLVANIAN (CARBONIFEROUS) 

SYSTEMS IN THE UNITED. STATESWEST VIRGINIA AND MARYLAND 

By THOMAS ARKLE, JR./ DENNIS R. BEISSEL./ RICHARD E. LARESE/ EnwARD B. NuHFER/ DouGLAS G. PATCHEN/ RICHARD A. SMOSNA/ WILLIAM H. GILLESPIE,2 RICHARD LuND,3 C. WARREN NoRTON/ and HERMAN 

W.PFEFFERKORN4 

ABSTRACT 

This review of the upper Paleozoic rocks (Mississippian, 

Pennsylvanian, and Permian Systems) of West Virginia and 

Maryland embodies the work of outstanding 19th-century 

and early 20th-century geologists. 

Upper Paleozoic rocks are predominantly composed of 

fine- to medium-grained clastic materials, which were deposited as a complex delta; exceptions are the organie and 

chemical deposits interspersed throughout the section. Delineation of facies changes, thickening characteristics and trends 

of thick units, and distribution of traceable beds such as 

coal and limestone, suggest structural control of deltaic 

sedimentation during late Paleozoie time. An irregular surface on Mississippian strata marks a break in sedimentation 

(unconformity) between Mississippian and Pennsylvanian 

time, except in areas of continuous sedimentation on or 

near exposures in southern West Virginia. 

Mississippian rocks contain frequent marine horizons. 

Dally's work on Mississippian invertebrate faunas indicates 

.that Pocono deposition was time-transgressive, ranging from 

early Kinderhookian through late Osagian in the south, and 

late Osagean through Meramec·ian in the north. The Maccrady Formation is Meramecian, although the basal units 

may be late Osagean. The basal Greenbrier Group is middle 

Meramecian in the south, correlating with the type area, 

whereas upper parts of the formations range into the 

Chesterian. However, the northern Greenbrier is early Chesterian. Mauch Chunk rocks are middle to late Chesterian. 

Mississippian vertebrate evidence is sparse. The Pocono 

and Maecrady have yielded no identifiable vertebrates. Greenbrier rocks contain rare Meramecian vertebrates in the south 

and somewhat more common Middle and Late Mississippian 

faunas to the north. Mauch Chunk faunas correlate with 

the type Chesterian and are similar to Upper Visean rocks 

in Britain. Appalachian and European Carboniferous floras 

are very similar, although detailed correlation is hard because of lack of studies. 

Invertebrate faunas in Pennsylvanian rocks are relatively 

uncommon. In the older mining district (southern West 

Virginia), the Pocahontas and New River Formations eontain no useful marine beds. The Kanawha Formation contains several marine faunas of Morrowan, Atokan, and basal 

Desmoinesian age. Vertebrate evidence is similarly laeking 

in the older mining district. One basal Kanawha Forma-tion 

locality yields vertebrates giving a tentative Morrowan age. 

Allegheny rocks of the younger mining district (northern 

West Virginia) possess no useful marine beds, although 

correlative strata in adjacent States are Desmoinesian. 

Lower Conemaugh marine zones are Missourian through 

lower Virgilian in age. Upper Conemaugh, Monongahela, and 

Dunkard beds are barren of marine fossils. 

Conemaugh and early Monongahela vertebrates in the 

younger mining district show Virgilian affinities. Sediments 

above the Benwood limestone contain vertebrates corresponding to Wolfcampian faunas. The upper part of the Greene 

Formation above the Burton sandstone has a possible Leonardian correlation. Pennsylvanian paleobotany needs more 

study, but a basic zonation is being worked out and correlated with the European sequence. 

INTRODUCTION 

Upper Paleozoic rocks underlie 81 percent of western and southern West Virginia and much of Garrett 

County, smaller areas of Allegany County, and a few 

hilltops of Washington County in Maryland. This 

paper reviews the early geologic work, physiography, SJtructure, and mineral resources, and focuses 

upon the lithostratigraphy and biostratigraphy. 

Figure 1 shows the historical development, to the 

present, of West Virginia/Maryland late Paleozoic 

nomenclature. It also shows the approximate relationships of rock divisions to (1) U.S. midcontinent 

series time-rock units, and (2) the European stages 

(Moore and others, 1944, chart 6 ; Weller and others, 

1948, chart 5; Dunbar and others, 1960, chart 7; 

McKee and Crosby, 1975, p. 2) . 

The Mississippian and Pennsylvanian sections in 

the United States are approximate equivalents of, 

1 West Virginia Geological and Economic Survey, Morgantown, W. Va. 

26606. 2 Department of Geology, West Virginia University, Morgantown, W. 

Va. 26606. 3 Department of Biology, Adelphi University, Garden City, L. I., N. Y. 

1'1530, and Research Associate, West Virginia Geological and Economic 

Survey. 4 Department of Geology, University of Pennsylvania, Philadelphia, Pa. 

19174. 

Dl 
D2 THE MISSISSIPPIAN AND PE~NSYLVANIAN SYSTEMS IN THE UNITED STATES 

SYSTEM 

Lower 

Permian? 

MIDCONTINENT 

SERIES 

Wolfcampian 

VIRGINIA 

1835-1844 

XVI 

MARYLAN~WEST VIRGINIA 

NORTH SOUTH 

a. Greene 

e Formation (!) 

'E 

t-,....-----r - - (1) - - - .: 

§ Washington 

{/) 

::> 

0 

a: 

c 

.!!! ... c 

~1 Q.~ 

=>c c 

:. 

Virgilian XV 

XIV 

Missourian 

o Formation 

Monongahela 

Group 

Conemaugh 

Group 

------ -~------~---------~ 

Desmoinesian 

r--- (2) ---

Atokan 

(Lampasas) 

Morrowan 

xm 

xn 

Allegheny 

Formation 

Pottsville 

• • •• •••• ? ••••••• 

Charleston 

Sandstone Group 

Kanawha 

Formation 

New River 

Formation 

~t-------1 

Pocahontas 

Formation 

Bluestone 

Formation 

Princeton z 

0 

a:l 

a: 

c( 

0 

Devonian 

---? ---

Chesterian 

XI 

~ ~----4'. ~ ~ XI 

Mauch 

Chunk 

Group 

Sandstone 

Hinton 

Formation 

Bluefield 

Formation 

Greenbrier Group 

~ 

1- -

M-era-mec-ian_ -·t-----+t'........_ ~ ~ ~~"-"'-.. """-~ "'-.. '""-~'----------1 1 Maccrady Formation 

Osagean 

X Pocono Group 

Kinderhookian 

IX Hampshire I Chemung 

(1) Position of Washington coal. (2) Position of Coalburg or Stockton coals. 

FIGURE 1.-Late Paleozoic classification. 

EUROPEAN 

STAGES 

Sakmari~;~n 

.( 

Stephanian 

Westphalian 

Upper 

Namurian 

Lower 

Namurian 

-------

c 

.!!! 

E 

IU 

c 

0 

Visean 

Tournaisian 

_.__? --

respectively, the lower and upper Carboniferous of 

Europe. The term "Permo-Carboniferous" (Wilmarth, 1938, p. 1640) was commonly used in early 

geologic reports in the United States, following the 

practice of many European workers. The U.S. Geological Survey included the Permian Series as the 

upper epoch of the Carboniferous until 1941 (Dunbar and others, 1960, p. 1767). The Dunkard Group, 

essentially of Permian age, is included in this discussion, because sedimentation continued without 

interruption from the Monongahela Group of Pennsylvanian time into the Dunkard Group. A long controversy continues over the as·signment of the Dunkard Group to the Permian System (Fontaine and 

White, 1880, p·. 105-120; Dunbar and others, 1960, 

p. 1789, 1790; Barlow, 1975, p. vii-xviii). 

The stratigraphic nomenclature used in this paper 

has not been reviewed by the Geologic Names Com:-

mittee of the U.S. Geological Survey. The nomenclature used here conforms with the current usage of 

the West Virginia Geological and Economic Survey, 

with the exceptions of the term "Charleston Sand-
WEST VIRGINIA AND MARYLAND D3 

stone Group" (fig. 1) and Lower No. 5 Block, Upper 

No. 5 Block, and No. 6 Block coals (R. S. Reppert, 

oral co~mun., 1977) (fig. 10). 

ACKNOWLEDGMENTS 

Many persons and agencies contributed to the organization and preparation of this report. A steering 

committee directed the progress of the paper. It consisted of Alan C. Donaldson and John J. Renton, 

West Virginia University, Morgantown, W. Va.; 

Monty H. Nock, Maryland Geological Survey, Baltimore, Md. ; and Robert B. Erwin, Director, and 

Richard E. Larese, Douglas G. Patchen, Carl J. 

Smith, Larry D. Woodfork, and Thomas Arkle, Jr., 

staff members of the West Virginia Geological and 

Economic Survey, Morgantown. 

The authors offer special acknowledgments to 

Charles W. Lotz, Jr., for layout .and preparation of 

12 figures and to Thomas R. Jake for layout; to Fred 

Schroyer, Steven W. McClelland, and C. Warren 

Norton for editorial review; and to Jean Fullmer for 

hours of service in several typings of the manuscript. All are members of the staff of the West Virginia Geological and Economic Survey. 

Biostratigraphic material was prepared as follows: Mississippian, Pennsylvanian, and Permian 

plants, by William H. Gillespie, West Virginia University, Morgantown, W. Va., and Herman W. Pfefferkorn, University of Pennsylvania, Philadelphia, 

Pa.; Mississippian, Pennsylvanian, and Permian 

vertebrates, by Richard Lund, Adelphi University, 

Garden City, Long Island, N.Y.; Pennsylvanian invertebrates, by C. Warren Norton, and Mississippian invertebrates, by Richard A. Smosna, both of the 

West Virginia Geological and Economic Survey, 

Morgantown. 

The remaining sections of the paper were prepared by members of the staff of the West Virginia 

Geological and Economic Survey: Introduction, early 

geologic work, physiography, structure, coal, and 

lithostratigraphy of Pennsylvanian and Permian 

Systems, by Thomas Arkle, Jr. ; ground water, by 

Dennis R. Beissel; con.struction and industrial minerals and iron ore, by Edward B. Nuhfer and Richard E. Larese; oil and natural gas, by Douglas G. 

Patchen; and lithostratigraphy of Mississippian 

System, by Richard A. Smosna. 

EARLY GEOLOGIC WORK 

A colonial military road crossed Maryland and 

Pennsylvania to Fort Duquesne (Pittsburgh) in the 

mid-18th century. This road was extended to Wheeling in what was then western Virginia and became 

the National Road in 1818, parts of which are now 

U.S. Route 40. Improvements to this road and the 

completion in 1852 of the Baltimore and Ohio Railroad across Maryland and northwestern Virginia 

(between Baltimore a:nd Wheeling) opened the area 

for geologic study and subsequent mineral developments during the first half of the 19th century. 

The major rock divisions of late Paleozoic age in 

western Viriginia (much of which became West 

Virginia on June 20, 1863) and Maryland (fig. 1) 

were first studied and described between 1835 and 

1844 by W. B. Rogers (1884), State Geologist of 

Virginia, and by his brother H. D. Rogers (1838, 

1840, 1844, 1858), State Geologist of Pennsylvania. 

The Rogers brothers (Pennsylvania's First Survey) and the staff of the Second Pennsylvania Geological Survey in 1875, under J. P. Lesley ( 1876), 

contributed greatly to geologic knowledge of Maryland, the Virginias, Pennsylvania, and Ohio. 

The first Maryland Geological Survey was organized in 1833 under J. T. Ducatel, State Geologist, 

and J. B. Alexander, State Topographic Engineer; 

the third and present Maryland Survey was organized on March 11, 1896, under William. B. Clark 

(1897, 1905). The West- Virginia Geological Survey 

was organized on February 20, 1897, under Israel C. 

White (1891, 1903, 1908), formerly of the Pennsylvania and U.S. Geological Surveys. 

A growing coal industry focused on commercial 

coals during the first quarter of the 20th century. 

Correlation p·roblems, particularly in Middle Pennsylvanian strata, were posed by bed configuration 

and lithofacies changes between the strata deposited 

on the northwestern West Virginia/Maryland craton and the southern West Virginia basin. 

The paleobotanical work of White (1900a, b; 

1913), showed that northern West Virginia's Allegheny Formation coal was younger than that of 

southern West Virginia's Kanawha Formation. 

Campbell (1903) resolved the mapper's dilemma by 

showing a facies change involving the stratigraphic 

equivalents of: (1) the upper Pottsville (Homewood 

sandstone), Allegheny, and lower Conemaugh strata 

of northern West Virginia; and, (2) the Charleston 

sandstone (Campbell, 1901, p. 5) along the Elk River 

near Charleston (fig. 1) . 

Geologic maps and reports on the upper Paleozoic rocks of West Virginia were completed between 

1906 and 1939 by G. P. Grimsley, Ray V. Hennen, 

C. E. Krebs, D. B. Reger, J. L. Tilton, P. H. Price, 

and L. M. Morris, assisted by W. A. Price, Rietz C. 
D4 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Tucker, W. F. Prouty, D. D. Teets, Jr., Robert M. 

Gawthrop, and E. T. Heck of the West Virginia Geological Survey, and David G. White and George H. 

Girty of the U.S. Geological Survey. 

Maps and reports on upper Paleozoic geology in 

Maryland's Allegany, Garrett, and Washington 

Counties were completed between 1900 and 1951 by 

Cleveland Abbe, Jr., -G. C. Martin, C. C. O'Hara, 

W. B. Clark, R. B. Clark, R. B. Rowe, Heinrich Ries, 

and Ernest Cloos, of the Maryland GeologiC'al Survey, which by the 1950's had become the Maryland 

Department of Geology, Mines, and Water Resources. The ~stratigraphy of Maryland's coal measures was revised in the second coal report (Swartz 

and Baker, 1922). During World War II, exploration 

for coal and refractory clay by the U.S. Bureau of 

Mines and the U.S. Geological Survey culminated in 

EXPLANATION 

Dunkard 

Monongahela 

Conemaugh 

~ 

~~ ~ f:.::.:,.·:::~.1-AII-e-ghen_y __ J -~ Allegheny-

~ Pottsville 

~ Oiliii] Kanawha - ~ -- Pottsville CB New River undivided 

ITII] Pocahontas 

~ Mauch Chunk ] ~ Mississippian undivided 

~ . Greenbrier-Macaady 

IIIIIIIIIIID _B_oco_n_o __ _ 

c=J. Older rocks 

the remapping of the Pennsylvanian of Maryland. 

This remapping was done in the early 1950's by Karl 

Waage of the U.S. Geological Survey and T. M. 

Amsden of the then Maryland Department· of Geology, Mines, and Water Resources. (fig. 2). 

PHYSIOGRAPHY 

The upper Paleozoic strata of West Virginia and 

Maryland form part of the Appalachian Plateaus 

province (fig. 3) and limited synclinal-mountain 

areas of the Valley and Ridge province farther east. 

The Appalachian Plateaus province extends from 

west of the Ohio River ·eastward across the Allegheny Mountain ·section of the plateau, to the Allegheny Front. The Allegheny Front is underlain by 

resistant Pottsville sandstone. The steep slope to the 

east, leading down to the Valley and Ridge province, 

!~ t\ I ,J· , ____ / 

/ 

50 MilES 

-EJ~~i[311~ 50 KilOMETERS 

FIGURE 2.-Geologic map of the late Paleozoic of West Virginia and Maryland. 
WEST VIRGINIA ·AND MARYLAND D5 

0 H I 0 

KENTUCKY 

P E N N S Y L V A N I A 

VIRGINIA 

50 MILES 

-ll!:::::iMA~~---=3--

50 KILOMETERS 

FIGURE a.-Physiographic map of West Virginia and adjacent Maryland. 

is on less resistant Mississippian and older strata. 

The Appalachian Plateaus province is deeply dissected, hilly to mountainous country, and the outliers 

are linear mountainous ridges of sandstone and 

shale containing a few irregular coal beds (figs. 

2-4). 

The water of the plateau and southeastern Lower 

Mississippian outliers drains westward to the Ohio 

River. As shown in figure 3, the north-flowing 

Monongahela drainage, the. south-flowing Greenbrier River, and the west-flowing Elk and Little 

Kanawha Rivers all begin in the high country of 

Randolph and Upshur Counties near Spruce Knob, 

Pendleton County, the highest point in West Virginia (1,482 m or 4,862 ft) and the environs of the 

Catskill-Pocono stratigraphic anomaly (Flowers, 

1956, p. 8, 10-14; fig. 4). Waters of eastern Tucker, 

Grant, and Mineral Counties, West Virginia, the 

eastern slope of the Allegheny Front, most of western Maryland, and the northern lower Mississippian 

ou'tliers flow into ~the Potomac River, thence east to 

the Chesapeake Bay and the Atlantic Ocean. 

Only two rivers entirely cross West Virginia: the 

Ohio crosses the State from north to south, and the 

New/Kanawha Rivers, as a system, cross east to 

west. The Ohio River's glaciofluvial sand-and-gravel 

deposits are dominated by rock debris from hard 

sandstone and quartzite that emanated from ablat-
D6 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

EXPLANATION 

Anticlinal axis 

Syndinal axis 

-Fault 

t=:='??] 

l:::=====:J Catskill-Pocono 

stratigraphic anomaly 

• 

• ALLEGHENY 

: MOUNTAIN 

• 

• • 

.. FOLDED 

50 MILES 

FIGURE 4.-Structural map of the late Paleozoic of West Virginia and Maryland. 

ing Pleistocene glaciers north of West Virginia. The 

New /Kanawha River system begins near Blowing 

Rock in North Carolina's Blue Ridge Mountains and 

flows across the Valley and Ridge province, and the 

Appalachian Plateaus province to Point Pleasant 

on the Ohio River. Some granitic and metamorphic 

rocks are present in the bedload deposits. of the 

New /Kanawha Rivers. The bedload sand-and-gravel 

deposits of all other streams of West Virginia are 

largely of sandstone, the rock most resistant to 

physical and chemical disintegration, and other sedimentary rock types indigenous to the Valley and 

Ridge and Appalachian Plateaus provinces. 

STRUCTURE 

The upper Paleozoic strata of West Virginia and 

Maryland are exposed on the eastern side of a synclinal belt extending north-nor-theast from the subsurface in Alabama to near the Great Lakes in Ohio 

and New York, a distance of 1,448 km ( 900 mi) 

(fig. 4). These strata are infolded between the Appalachian tectonic I>elt on the east and the more 
WEST VIRGINIA AND MARYLAND D7 

stable Indiana-Ohio upland and the Lexington (Kentucky) and ·Jessamine (Tennessee) do-mes on the 

west. 

Early work depicted the .surface structures of upper Paleozoic strata as reflections of episodic basement deformation. The deformation intensity 

declined progr.essively from the crystalline Appalachians (Piedmont and Blue Ridge provinces) on 

the east to the basement of the sedimentary Appalachians (Valley and Ridge and Appalachian Plateaus provinces) on the west. Since World War II, 

however, deep drilling for natural gas on anticlinal 

structures of the sedimentary Appalachians has 

found many thrust faults. A restudy of the structures, based on drilling, geophysical logging, and 

surface geological investigations, suggests this alternative view of Appalachian tectonics·: A decollement 

zone (perhaps in Silurian evaporites) and associated 

thrust faults extending upward into Middle Devonian strata, plus folding, are suggested as the mechanisms for the formation of .surface structures in 

the Valley and Ridge and subsurface structures in 

the Appalachian Plateaus. Structural manifestations 

in Cam,brian and Precambrian strata are believed 

coincidental to this later tectonic activity in the Valley and Ridge province and subsurface of the Appalachian Plateaus province (Rodgers, 1972). 

Delineation of facies changes, thickening characteristics and trends of thick units, and distribution 

of traceable beds such as ·coal and limestone, suggest 

later structural control of deltaic ~sedimentation during late Paleozoic time (Arkle, 1974). Compressional forces formed the surface structure of the 

Appalachians from at least Mis~sissippian time 

through the rest of Paleozoic depo'sition, after the 

earlier period of extensional tectonics. The entire 

ro~ck section was further deformed at the end of 

Paleozoic deposition (Rodgers, 1972, p. 4). 

Two surface-structural trends, running eastnortheast and north-northeast, are evident in West 

Virginia (note arrows in fig. 8, and relate these to 

fig. 4). These trends conform to the structural 

salients of the Appalachian Mountains. Southern 

West Virginia's upper Paleozoic strata are ~shown in 

a northeast-trending, northwest-dipping broad monoclinal structure (fig. 4). Strata inclination is moderate, reaching 48 m/km (250 ft/mi) on the Warfield anticline, the dominant structure. This di'p 

increases to 57 m/km (300ft/mile) on the Dry Fork 

anticline, bringing Upper Mississipian strata to the 

surface and exposing basal Pennsylvanian beds just 

to the southeast. Farther southeast, in southeastern 

Mercer and Monroe Counties (,see fig. 3 for county 

location), deformation intensity of the thick, less 

resistant Mississippian strata increases progressively between the higher Pennsylvanian escarpment 

and the Valley and Ridge province, where middle 

and lower Mississippian (and older) strata are vertical or slightly overturned (figs. 2-4). 

En echelon structures, trending north-northeast in 

the Allegheny Mountain section (figs. 3 and 4) bring 

resistant Pottsville sandstone to the surface, forming mountainous areas. More hos.pitable country is 

formed on the less resistant Mississippian and Devonian strata in breached anticlines and on the 

younger Pennsylvanian ·coal-bearing strata in adjacent synclines. Anticlines are slightly asymmetric 

to the west, and maximum dips are 20°. The anticlines plunge south-southwest over the CatskillPocono stratigraphic anomaly and lose identity in 

southern West Virginia monoclinal structure. 

The Nineveh syncline is the axis of the Dunkard 

basin, a north-northeast-trending synclinorium extending from Huntington, W.Va., to· Pittsburgh, Pa. 

The basin configuration is best delineated by Pittsburgh coal exposures (fig. 4). Normal to the Nineveh 

syncline, the Pittsburgh coal is 518 m (1,700 ft) 

above sea level on Scot~ch Hill, Preston County, and 

320 m (1,050 ft) at the head of the Monongahela 

River in Marion County, both in west Virginia; it 

is 378 m (1,240 ft) at its western exposure in Belmont County, Ohio. The Pittsburgh coal is slightly 

above sea level along the Nineveh axis in. West v·irginia. West of the Allegheny Mountain ~section, 

strata in the synclinorium dip 38 m/km (200 ft/mi), 

decreasing to less than 4 m/km (20 ft/mi) on the 

Ohio River. 

The ano-malous Burning Springs anticline lies 

athwart the Dunkard basin axis. This anticline is 

complex, steeply dipping, north-trending and plunging, and is surrounded by nearly flat-lying strata. 

Surface dips range from as much as 55° on a narrow flat crest on the east flank, to 70° on the west 

flank. Here, as on many other anticlines in the Appalachian Plateaus province, deep drilling has disclosed thrust faults extending into the Devonian. 

Projection of the relatively iSimple Appalachian 

Plateaus surface structures into the subsurface is 

not valid because they may not be maintained at 

depth (Woodward and others, 1959, p. 164). .. , 

MINERAL RESOURCES 

Mineral resources from upper Paleo·zoic rocks 

(fig. 5) are economically important to West Virginia 

and Maryland. 1Coal accounted for 94 percent of 

West Virginia's mineral ·resources, which were 
DB THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

EXPLANATION 

~ 

~ 

NUMERAL PRECEDING SYMBOL INDICATES NUMBER OF 

OPERATIONS IN 1976, BY COUNTY 

4 !I Underground coal mine 39 0 Surface coal mine 

Original minable extent 

of coal seams In 1 !I LS Limestone mine 8 ~ LS Limestone quarry 

West Virginia and Maryland 

2 !I CL Clay mine 1 ~CL Clay pit 

Gas field OUfield 2 ~ SS Sandstone quarry 

Mississippian 

outaop 

50 MILES 

---E=-~~.c~·~~ 50 Kn.OMETERS 

FIGURE 5.-Late Paleozoic mineral resources of West Virginia and Maryland. 

valued at $3.5 billion (at the source) in 1976; it accounted for 28 percent of Maryland's mineral resources, valued at $172.9 million in 197 4. Upper 

Paleozoic strata also provide the following materials 

in West Virginia and Maryland : all the refractory 

clay; all the concrete sand from crushed sandstone ; 

most of the oil, clay, shale, and crushed sandstone; 

appreciable natural gas; appreciable limestone for 

aggregate and cement manufacture; and some industrial limestone. 

COAL 

During the mid-1700's, explorers and surveyors 

noted .the existence of coal in West Virginia and 

Maryland. In 1811, coal fired the first steamboat on 

the Ohio River. In 1840, W. B. Rogers (1884) reported coal production o.f 271,157 t (m,etric tons) 

(298,894 short tons) in West Virginia; about 70 percent of this coal was used by the salt industry on 

the Kanawha River above Charleston. 

In Maryland, two coal mines operated as early as 

1782 and 1804. Coal was ·carried east to Cumberland, 

Md., over the National Road as early as 1820. Access 

to the northern coal fields was provided by the 

Chesapeake and Ohio Canal (completed in 1850) 

and the Baltimore and Ohio Railroad (completed in 

1843), both connecting the eastern seaboard to Cum-

·berland. 
WEST VIRGINIA AND MARYLAND D9 

West Virginia coal production increased slowly 

until the completion of the rail network in the late 

1800s. Original coal resources, measured to 30.5 C_!n 

( 12 in.) thick in the western 69 percent of the State, 

were estimated at 105.9 billion t (116.7 short tons). 

Production expanded rapidly to 132.5 million t 

(146.1 million short tons) in 1927. Only during 

World War II and the postwar years to 1947 did 

production exceed 136.1 million t (150 million short 

tons). Production remained high through the recent 

1965-67 peak, and fell irregularly to a 92.3-milliont (101.7 million short tons) low in 1974. Coal production in 1976 was 98.1 million t (108.1 million 

short tons) from 903 underground and 504 surface 

or "outside" mines (West Virginia Dept. Mines, 

1976, p. 15) ; surface mining accounts for 19 percent 

annually. 

More than 70 percent of West Virginia's annual 

coal production ·Comes from low- to high-volatile, 

generally low-sulfur ( < 1 percent) seams at multilevels in southern West Virginia. The remainder is 

produced from high-volatile, high-sulfur ( > 1 percent) coal of northern West Virginia, principally 

the thick, uniform Pittsburgh coal. ·Correlative· coals 

grade into low- to medium-volatile (and locally lowsulfur) ·coal in the Allegheny Mountain section (fig. 

4) of West Virginia and Maryland. Much of Maryland's early production was from the Pittsburgh coal 

in Allegany ·County, but when this coal was depleted 

early in the 20th century, mining shifted to the less 

uniform and thinner Allegheny and Conemaugh 

coals. 

About a third of the coal production of West Virginia is used to generate electricity annually, more 

than half is used domestically or exported for metallurgical purposes, and the remainder supplies industrial and retail markets. Mining employment 

reached 121,280 in 1923. After machines were introduced, employment declined to 41,593 in 1968, and 

stood at 59,802 in 1976 (West Virginia Dept. Mines, 

1976, p. 13-14). 

West Virginia coal reserves are estimated at 33.1 

billion t (36.5 billion short tons.) from seams >71.1 

em (28 in.) thick. Appreciable reserves <71.1 em 

(28 in.) thick are available. About 1.9 billion t (2.1 

billion short tons) of reserves is recoverable by surface mining. Some 33.4 percent of reserves is lowsulfur ( < 1 percent) coal (U.S. Bur. Mines, 1971, 

p. 118; 1974, p. 275). 

Maryland's coal production increased from 1,548 

t ( 1, 706 short tons) in 1842 to a 5.0-million-t ( 5.5 

million short tons) peak in 1907. Subsequently, production averaged about 4.1 million t ( 4.5 million 

short tons.) per year until 1918, and thereafter declined irregularly to a 453,600-t (500,000 short tons) 

low in 1954. In recent years, coal production for 

steam generation has increased slowly to a 2.4-mil-

. lion-t (2.7 million short tons) high in 1976. Surfacemining methods, introduced during World War II, 

now account for 94 percent o.f Maryland's coal production. 

Total recoverable reserves in Maryland are estimated at 775.6 million. t ( 854.9 million short tons) 

for seams more than 68.6 em (27 in.) thick. About 

90.7 million t (100 million short tons) is recoverable 

by surface-mining methods; the remainder is recoverable only .by underground mining. Additional 

coal reserves exist in seams thinner than 68.6 em 

(27 in.) (Weaver and others, 1976, p. 1-3). 

OIL AND NATURAL GAS 

West Virginia's oil and gas industry began with 

oil production from the Rathbone Well (Wirt 

County) in 1859. The State ranked second or third 

in crude oil production from then until 1900, the 

peak year. Production and the State's rank have 

both decreased steadily during this century. Annual 

oil production is now only 12 percent of 1900's, and 

annual gas production is now about 52 percent of 

that produced during the. peak gas year, 1916. 

During the early years of the industry (the last 

half of the 19th century), shallow Pennsylvanian 

sandstone (Pottsville, Allegheny, Conemaugh, and 

Monongahela strata) along the Burning Sprtngs 

anticline and Ohio River was drilled for oil and associated natural gas. Deeper drilling penetrated important oil and natural-gas reservoirs in Mississippian sandstone and in thin basal Greenbrier sandy 

dolomite in western West Virginia. More recently, 

natural-gas reservoirs have been developed in Mississippian sandstones in southern West Virginia 

(fig. 5) . Driller'·s names have been given to 11 Mississippian and 10 Pennsylvanian producing sands 

between the Berea sand (base of Pocono ·Group) 

and the Minshall sand (Monongahela Group) . 

West Virginia has 357 fields in 53 counties; Maryland has 1 field. In West Virginia, oil and natural 

gas are produced from upper Paleozoic reservoirs in 

43 of the 53 counties; in Maryland, no county produces oil or gas from upper Paleozoic rocks. 

At the end of 1976, West Virginia's original oil 

in place was estimated at 351,966 thousand t (2,625,-

316 thousand barrels), 10.7 percent in Pennsylvanian reservoirs and 58.5 percent in Mississippian. 

An estimated 73,089 thousand t ( 545,173 thousand 

bbls) was assumed to be recoverable, 6.6 percent in 
D10 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Pennsylvanian and 55.3 percent in Mississippian res·ervoirs. 

Currently, Pocono and Greenbrier reservoirs are 

the most common Mississippian targets in the State 

for development and in several southern counties 

for exploration. The Mauch Chunk sands are also 

productive in this southern area. In Pennsylvanian 

strata., only basal sands are being developed at present. 

CONSTRUCTION AND INDUSTRIAL MINERALS 

Limestone.-Commercial limestone production 

(fig. 5) indicates the economic importance of the 

Mississippian Greenbrier Group. The Greenbrier, a 

group o.f marine limestones, has exceptional thickness, persistent continuity, generally acceptable 

purity, and extensive areas of surface exposure. 

Most Greenbrier limestone is used for road aggregate, cement, and agricultural lime. High-purity 

limestone from the southern ~counties is also used as 

rock dust in coal mines. 

Lateral and vertical variations in purity are documented in the Greenbrier Group. Textural and mineralogical variations along the northeast-trending 

outcrop belt from Tucker ·County to Monroe County 

W. Va., have been described by Leonard (1968). 

The entire limestone sequence . of the Greenbrier is 

usable, but the highest purity limestone is found in 

the Union Formation. The "white oolite member" of 

the upper Union (Leonard, 1968, p. 101) persists 

through Monroe County and much of Greenbrier 

County, where it is extensively quarried. As the 

oolitic beds diminish in size and continuity to the 

northeast, limestone purity generally decreases. 

Westward, beneath the plateau, insoluble residues 

generally increase as the Greenbrier grades toward 

the .sandier facies found in the subsurface of western West Virginia. Four quarries operate in the 

basal .sandy Greenbrier (Loyalhanna) in Garrett 

County, Md. 

Present mining operations are restricted to outcrop areas and include both open-pit and underground mines (Larese and others, 1977). The underground mines enter surface exposures and follow 

only the gentle dips of the strata. Deep shaft mining· 

in western West Virginia has been discussed 

(Kusler and Corre, 1968) but has not yet been undertaken. 

Some thin Pennsylvanian limestone beds of minor 

economic importance are utilized locally. These beds 

were described by McCue, Lucke, and Woodward 

( 1939) ; they were further discussed and were classified according to their usability, 1

by the West Virginia University Coal Research Bureau (1965). 

Most of this limestone is nonmarine ; a lacustrine 

origin has been attributed to some beds. All beds 

have persistently high dolomite and (or) insolubleresidue oontent and are not potential sources of 

high-calcium limestone. Of these beds, the Benwood 

and Redstone limestones of the Monongahela Group 

are the most important commercial sources. Benwood exposures occur in Ohio, Brooke, Tyler, Doddridge, and Harrison Counties ; minable thicknesses 

of the Redstone occur in Monongalia, Harrison, 

Marion, and Upshur Counties. Present extraction 

yields local road aggregate and minor amounts of 

agricultural lime. 

Sandstone.-Upper Paleozoic sandstone is currently extracted in 23 quarries in 13 counties (fig. 5) 

and is used as road-base aggregate, concrete sand, 

and, to a lesser extent, dimension stone. 

High-silica ( 98 percent) sandstone is mostly restricted to the Pottsville ·Group (Lower Pennsylvanian), Mauch Chunk Group (Upper Mississippian), and Pocono Group (Lower Mississippian) 

(Arkle and Hunter, 1957). In northern West 

Virginia, the Connoquenessing and Homewood Sandstones (Pottsville Group) have been quarried for 

glass sand. In the southern part of the State, highsilica material at the horizons of the Nuttall, Raleigh, and Pineville sandstones (New River Formation, Pottsville Group) underlies small areas, whiCh 

are suitably located for mining (Arkle and Hunter, 

1957). 

Sandstones of the Mauch Chunk and Pocono 

Groups are impure, commonly containing appreciable argillaceous material; consequently, many do not 

qualify for high-silica applications. However, two 

sandstones within the Mauch Chunk Group, the 

Stony Gap and Droop, are relatively pure and may 

have potential as special-purpose sands. An additional pure quartz-cemented conglomeratic member 

of the Pocono Group has been quarried for construction aggregate in Preston County and adjacent areas 

of Maryland. 

The youngest Paleozoic sandstones in West Virginia-the Conemaug.h-Monongahela Group in the 

Pennsylvanian: and the Dunkard Group in the Permian-are generally too impure to be high-silica 

sandstone sources. These units are locally quarried 

for road-base aggregate and historically have been 

used for dimension sandstone and abrasive stone 

(grindstone, pulpstone) (Eggleston, 1975). 

Clay and shale.-West Virginia's clay and shale 

industry is relatively small. Four mines produce clay 
WEST VIRGINIA AND MARYLA~D D11 

and shale for manufacturing common brick, fire 

brick, block, and clay stemming. 

Only clay and shale of the Pennsylvanian Allegheny Formation and Conemaugh -Group are currently being used .. Two Allegheny clays, the Lo:vyer 

Kittanning and Clarion, .have excellent fire-clay 

qualities and are presently being extracted by underground methods in. Hancock County (fig. 5). 

These clays directly underlie the Lower Kittanning 

coal, and range from 2.1 to 6. 7 m ( 7 to 22 ft) in 

thickness in the northern panhandle. Reserves have 

been estimated at 1 billion tons under less than 500 

feet overburden (Cross and Schemel, 1956) . Allegheny plastic and flint clays are mined for produc~ 

tion of refractory fire ·brick and ground-and-calcined 

clay in adjacent parts of Maryland. Conemaugh 

shale is extracted from two quarries in Cabell and 

Lincoln Counties for manufacture of common brick, 

tile, and clay stemming. 

Recent work by Lessing and. Thomson ( 1973) has 

shown that many late Paleozoic clays and shales 

have potential for the manufacture of face brick, 

structural tile, lightweight aggregate, and sewer 

pipe. 

Salt.-N atural brines from upper Paleozoic strata 

have been used extensively in West Virginia, although the State's brine fields are presently inactive. 

Major sources were the "Salt Sands" in the Pennsylvanian Pottsville Group and the "Big Injun 

Sand" of the Mississippian Pocono Group. A compilation of geological information, production sites, 

chemical analyses, and economic utilization of these 

brines has been provided by Price and others 

(1937). 

IRON ORE 

Although there is no present iron mining in West 

Virginia, an active history of production from Pennsylvanian rocks was noted by Eggleston ( 1975, p. 

25) and Grimsley (1909, p. 106-107). The latter 

reference also gives the location, analyses, and na .. 

ture of the ore in various counties. Iron deposit~ 

from Pennsylvanian strata consist of impure sideritic-Iimonitic nodular beds which are discontinuous 

and sporadically distributed through the coal measures in a broad belt from Preston and Monongalia 

Counties through Kanawha and Wayne Counties. 

These occurrences will probably not be economically 

important in the foreseeable future. The sites, together with the abandoned remnants of iron furnaces and the implements made there, are mainly of 

historical interest. 

GROUND WATER 

Three [actors affect water quality from upper 

Paleozoic strata: ( 1) Mine drainage from Pennsylvanian strata pollutes water, principally in the 

northern ·part of the State, ( 2) in the oil and gas 

field.s (fig. 5), fresh water is degraded by upward 

migration of brine, and (3) variable ground-water 

quality conditions, ·both within and between aquifers, are caused by local geologic, hydrologic, and 

cuJ.tural phenomena. 

MISS:ISSI·P,PIAN SYSTEM 

Ground-water availability is highly variable in the 

Mississippian outcrop belt in West Virginia. Clark 

and others ( 1976) found well yields in southeastern 

West Virginia to be governed primarily by well 

depth, topography, geologic structure, and stratigraphy. Yields were generally higher in deep wells, 

valley wells, and wells near axes. Valley wells. in the 

Mauch Chunk Group had a higher median specific 

capacity than wells in any other Mississippian unit. 

Ground-water occurrence in the karst region, underlain ·by Greenbrier limestone in southeastern 

West Virginia, is controlled by interconnection of 

solution cavities and channels along fracture systems in carbonate ·strata. Wells .in .the Maccrady 

Formation and Pocono Group yield ·moderate water, 

but hillside and hillto·p wells in. the Maccrady may 

not yield enough for domestic use (Clark and others, 

1976). 

In northeastern West Virginia, wells penetrating 

the Greenbrier and Pocono Groups. have yields ~dequate for domestic use. Few wells. tap Mississippianage rocks outside the outcrop belt in eastern West 

Virginia and western ·Maryland; consequently, yield 

data are scarce. In the subsurface of western West 

Virginia, Mississippian-age rocks are usually below 

the freshwater I saltwater interface. 

PENNSYLVANIAN AND PERMIAN SYSTEMS 

Southern West Virginia.----Ground-water data for 

Pennsylvanian strata in southern West Virginia are 

scarce. A water-resources study of this area's Guyandotte River basin is in progress. 

Pottsville Group sandstones. are the most extensive aquifers in southern West Virginia. Doll and 

'others ( 1960) found that Pottsville sandstone in 

Kanawha County yields more water than does shale 

of the same group. Well yields ranged from 1 to 522 

gpm, averaging 118 gpm. The freshwater/saltwater 

interface is 90-150 m (300-500 ft) deep. Wilmoth 

(1967) reported 88,000 gpd/ft transmissivity from 
D12 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

an aquifer test in the Pottsville Group in Raleigh 

County. To the ,southeast in the New River basin, 

Clark and others ( 1976) found Pottsville wells to 

have a median specific capacity of 0.23 gpm/ft. They 

suggested that valley wells in the Pottsville would 

yield sufficient water for small municipal and industrial supplies. 

Sandstones overyling .the Pottsville are also major 

aquifers in southern W es,t Virginia. Wells in these 

sandstones produce primarily from fractures.· In 

Kanawha County, the average well yield was 125 

gpm, the deepest freshwater well being at 93 m 

(306 ft) (Doll and others~ 1960). A 13,000-gpd/ft 

transmissivity was reported by Wilmoth (1967) 

from an aquifer test in the same sandstones. 

Northern West Virginia and western Maryland. 

-In northern West Virginia, Pottsville strata have 

the highest potential for ground-water development. 

In the Monongahela River basin, Pottsville wells 

yield an average 44 gpm (Ward and Wilmoth, 

1968). Yields reach a maximum of 250 gpm, valley 

wells being the highest ·producers. Transmissivity 

values from aquifer tests reached a maximum of 

10,000 gpd/ft. The Pottsville contains saltwater west 

of a line from Morgantown in Monongalia County 

to Buckhannon in Upshur County. 

A ground-water study of eastern Monongalia 

County by Quagliotti (1974) revealed an average 

Pottsville sandstone well yield of 57 gpm. Maj pr 

aquifers were found throughout the Pottsville 

Group, but the lower Pottsville had the highest potential. 

Allegheny Formation sandstones provide adequate 

water for small to moderate industrial and public 

drinking supplies (Ward and Wilmoth, 1968). As in 

other Pennsylvanian strata, well yields in the Allegheny generally decrease from east to west in northern West Virginia. Average yields ranged from 31 

gpm in eastern Monongalia County ( Quagliotti, 

197 4) to 26 gpm over the entire Monongahela River 

basin (Ward and Wilmoth, 1968). In the Little 

Kanawha River basin, Allegheny well yields were 

less, but no average was reported (Bain and Friel, 

1972). All the highest yielding Allegheny wells were 

in valleys underlain by thick sandstone ·beds. A 

27,000-gpd/ft transmissivity was determined from 

an aquifer test in Allegheny strata in Taylor County 

(Ward and Wilmoth, 1968). 

Several Conemaugh Group sandstone units are 

considered to be aquifers in northern West Virginia 

and western Maryland. Well yields average about 10 

gpm, but transmissivities are generally less than 

1,000 gpd/ft. Basal Conemaugh sands contain saltwater in the western part of the Monongahela River 

basin (Wilmoth, 1966), and because of mining and 

drilling activity, poor quality water is found as far 

east as eastern Harrison ·County (Nace· and Bieber, 

1958). 

Wells producing from Monongahela strata generally have low yields. Mining activity througho.ut 

northern West Virginia and western Maryland has 

drained much of the Monongahela Group, particularly in outcrop areas. 

Basal Dunkard sandstones are the most important 

Penna-Pennsylvanian-age aquifers in Harrison 

County (Nace and Bieber, 1958) and the Little 

Kanawha River basin (Bain and Friel, 1972). Wells 

in the Dunkard Group average 13 gpm in the Monongahela River basin and 6 gpm in Mason and Putnam Counties (Wilmoth, 1966). The Dunkard is 

contaminated locally with saltwater from old oil 

wells. It also feeds many springs. with freshwater. 

In W-etzel County, Dunkard wells close to mapped 

fracture traces had significantly higher yields than 

did other wells (Sole and others, 1976). 

MISSISSIPPIAN SYSTEM 

LITHOSTRATIGRAPHY 

Lithologically, the Mississippian System may be 

divided into three parts (fig. 6) : (1) Lower sandstone (Pocono Formation) and overlying red shale 

(Maccrady Formation) , ( 2) middle limestone 

(Greenbrier Group) , and ( 3) Qpper red shale 

(Mauch Chunk Group). Mississippian strata crop 

out in or underlie all West Virginia counties (except Jefferson), but important exposures-including 

many type sections-occur only along the eastern 

part of the State (fig. 6). 

Cooper (1948, p. 258), pleading for future investigations, claimed that in the central Appalachians, 

geologists will find "some of the thickest and most 

varied seCitions of the Mississippian. * * *" Moreover, in Virginia and West Virginia, "the system 

therein probably ·contains the fullest Mississippian 

sectio·n on the North American continent." Indeed, 

the Mauch Chunk and Maccrady red beds are extraordinarily thick and extensive, whereas the 

Greenbrier limestones reflect the final major marine 

flooding of the region. Yet so little published work 

on the Mississippian of the State is available,! 

For this reason, most stratigraphic data in this 

paper are from West Virginia Geological Survey 

County ·Geologic Reports published between 1907 

and 1939 and from more recent unpublished graduate theses. Also, Dennison and Wheeler (1975) 
WEST VIRGINIA AND MARYLAND D13 

SOUTHEAST 

SYSTEM SERIES 

GROUP 

Mauch 

Chunk 

Chesterian 

z 

s; 

11. 

11. 

-~ 

ii) 

!a Greenbrier ::;: 

Meramecian 

Osagean \ Klnderhookia~ 

'In extreme southern West Virginia, 

uppermost beds of Bluestone Formation 

ore Pennsylvanian 

'Lower Maccrady Formation may be Osagean 

'Most of Hampshire Formation is Devonian 

FORMATION 

Bluestone 

Formation' 

Princeton 

Sandstone 

Hinton 

Formation 

Bluefield 

Formation 

Alderson 

Limestone 

Greenville 

Shale 

Union 

Limestone 

Pickaway 

Limestone 

Taggard 

Formation 

Denmar 

Formation 

Hillsdale 

Limestone 

Maccrady 

Formation2 

Pocono 

Formation 

NORTH 

FORMATION 

Mauch 

Chunk 

Formation 

f..---7-

Greenbrier 

Limestone 

Pocono 

Formation 

Hampsh1re 

Formation' 

have provided a general review of fluvial Mississippian strata o.f the southeastern United States. 

SYSTEMIC BOUNDARIES 

With only limited paleontological evidence, the 

Mississippian System base is traditionally put at the 

base of the Pocono Formation. The Berea Sandstone 

Member is the basal subdivision o.f the Pocono in the 

subsurface and consequently is considered to be the 

basal Mississippian stratigraphic unit, established 

solely as a convenient lithologic marker. 

Throughout most of West Virginia, lowest Pocono 

rocks intertongue with Upper Devonian Hampshire 

(Catskill) Formation red beds. The interpretation 

follows that the time boundary is not coincident 

with a lithologic boundary, and Dally (1956) 

thought the upper Hampshire to be partly of Mississippian age. In the southernmost counties, however, the Pocono grades downward into the Upper 

Devonian Chemung Group, the boundary being 

vaguely placed where thick beds o.f crossbedded, 

conglomeratic Pocono sandstone rest on flaggy beds 

of Chemung sandstone. 

The Mississippian upper boundary clearly coincides, with a marked erosional unconformity. From 

southeast to northwest across the State, the Pennsylvanian Pottsville Group rests, on successively 

older units of the Mississippian Mauch Chunk 

Group. In fact, pre-Pottsville erosion removed the 

entire Mauch Chunk and part to all o.f the Greenbrier in north-central and western West Virginia 

(Youse, 1964). In Hancock County (northern panhandle), the Pottsville sits directly on the Pocono 

Formation. Only in very southern West Virginia is 

the Mississippian-Pennsylvanian contact conformable. Along the West Virginia/Virginia State line, 

lowest Pottsville sandstones from the southeast intertongue with variegated Mauch Chunk shale and 
D14 THE MISSISSIP'PIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

siltstone to the northwest (England and others, 

1976). The uppermost Mauch Chunk beds. there are 

of Pennsylvanian age. 

TECTONIC INFLUENCE ON SEDIMENTATION 

Tectonism concurrent with sedimentation is illus-

.trated by ( 1) the pronounced subsidence o.f the 

southern basin and (2) the enormous. volume of detritus in the Appalachian basin. In the southern 

basin, as much as 1,700 m (5,576 ft) of continental 

and shallow-marine sediments was deposited (fig. 

7) ; simultaneously, less than 300 m (984 ft) was 

laid down on- a relatively stable shelf in the northwestern two-thirds of the State. In between, the 

Mississippian System thickens notably over a short 

distance (hinge line)_- In the Appalachian basin, 

combined uplift and erosion of an eastern landmass 

supplied the enormous volume of detritus, incluaing 

the molasse facies of the Pocono (Dally, 1956) and 

Mauch Chunk (Hoque, 1968). In southern West Virginia and Virginia, polymictic conglomerates of the 

Princeton Sands.tone (Mauch Chunk Group) have 

been identified as reworked Silurian, Devonian, and 

Mississippian sediments (Thomas, 1966). 

POCONO FORMATION 

The Pocono Formation has been mapped throughout the eastern outcrop belt, but subdivisions are 

generally thin and cannot be traced from one region 

to the next. Only in the extreme eastern panhandle 

are mappable units within the Pocono distinguished; 

hence, where the Rockwell, Purslane, and Hedges 

Formations (in ascending order) can be distinguished, the Pocono is raised to the rank of "group." 

The thickest Pocono Group section is in Berkeley 

County, where it totals 335m (1,099 ft) ; it thins to 

EXPLANATION 

FEET 

1500 

1000 

500 

Hampshire 

(: :;;:! Roo Shale 

~Limestone 

~S~ndstone Ia:..:.:..:..:. 

---------------

Shelf 

METERS 

500 

400 

300 

200 

100 

"Catskill island" 

10 20 I I 

1

1

0 2b ~o 4'o 

VERTICAl EXAGGERATION X 100 

30 MILES I 

~0 KILOMETERS 

Hinge 

line 

FIGURE 7.-Cross section of Mississippian strata along outcrop belt. 

SOUTH 

Basin 
WEST VIRGINIA AND MARYLAND D15 

150 m ( 492 ft) to. the southwest in Hampshire and 

Hardy Counties. The Rockwell Formation includes 

interbedded arkosic, conglomeratic, and argillaceous 

sandstone; sandy and silty shale; fine conglomerate; 

coal; and occasional plant -fossils. The Purslane 

Sands.tone is predominantly fine-grained sandstone 

alternating with conglomerate and some sandy 

shale; at the top are beds· of black shale· and coal. 

The Hedges Formation consists of sandy shale, thin 

beds of laminated argillaceous sandstone, black 

shale, and semianthracite coal. Plant fossils have 

been reported from the black shale in Hampshire 

County; this unit thins to the southwest and is absent in Hardy County. The upper contact of the 

Pocono Group 'is not seen because rocks younger 

than Pocono are not present in this area. 

In southern West Virginia, the Pocono Formation 

resembles the Pocono Group of the HampshireBerkeley County area, except that it is noticeably 

thinner (fig. 7). The undifferentiated Pocono ranges 

from 60 to 180 m (197 to 582 ft) in thickness, consisting primarily of brown, coarse-grained and conglomeratic cross.bedded sandstone. Sandy shale, 

some red, and lenses of impure coal and conglomerate are also present. In .the southern counties, the 

Sunbury Shale Member (traced via the subsurface 

to its type section in Ohio) is a black sandy shale 

containing minor sandstone; its thickness ranges 

from 5 to 50 m (16 to 164ft). Several authors have 

recognized the basal Berea Sandstone Member (a 

gas reservoir in the west) in the outcrop. In this 

area, the upper limit of the Pocono is placed above 

the coal-bearing strata and below Mac·crady Formation red shale or limestone. 

The Pocono Formation thins drastically in central 

West Virginia and actually is missing over a large 

territory called the "Catskill island" (Figs. 2 and 

7). The island was a deltaic lobe, standing above 

sea level (Dally, 1956). Consequently, an unconformity is present here between the Hampshire 

(Catskill) Formation and the overlying Greenbrier 

Limestone. 

North of this area, the Pocono Formation progres-

·sively thickens, reaching a maximum of 200 m ( 656 

ft) in Monongalia County (the thickening is mostly 

in the lower part). The unit is predominantly conglomeratic sandstone containing interbedded sandy . 

or calcareous shale, siltstone, rare limestone, and 

occasional coal streaks (Tucker County only). Coquinas of marine fossils, particularly brachiopods, 

are scarce in the sandstone beds. The upper contact 

with limestone of the Greenbrier Formation is 

sharp. 

MACCRiADY FORMATION 

The Maccrady Formation is restricted to outcrops 

in the southeastern counties and to the subsurface 

in the south. Its maximum thickness in the State, 

125 m ( 410 ft), is in Monroe County, but it thickens 

to the southeast into Virginia (where the type section is situated). The unit thins to the north and 

northwest and is absent north of Randolph County 

(fig. 7). On the whole, Maccrady thickness is quite 

variable, particularly in the subsurface, and indicates an upper erosion surface in those areas 

where it thins and pinches out (Youse, 1964; 

Flowers, 1956). The formation consists of red and 

purple arenaceous shale and siltstone and varying 

amounts of green and yellow shale, yellow lime&tone 

in the upper part, and calcareous sandstone. Minor 

anhydrite has been reported from these red beds in 

Wayne, McDowell, and Raleigh Counties. 

The Maccrady Formation has received scant geologic attention. Plant fossils are rare, as are marine 

fossils in the limestone beds. Dennison and Wheeler 

(1975) considered most of the Maccrady north of 

Mercer and Monroe Counties. to be of marine origin. 

GREENBRIER GROUP 

Southeastern West Virginia's Greenbrier Group 

is lithologically complex and very thick. It is dominated by limestone; interbedded shales provide a 

basis for subdivision. Marine fossils are abundant, 

and a few strata contain plant fossils. The lowest 

formation, the Hillsdale, is a cherty, argillaceous 

limestone which loses its shaly nature and thins to 

the north, pinching out in Pocahontas County. The · 

overlying Denmar Formation consists of both cherty 

and oolitic limestone, becoming shaly near the top 

(Wells, 1950). This shale may be red, calcareous or 

sandy, and contains plant and marine fossils. The 

next higher Taggard Formation is distinguished by 

red and green occasionally sandy shale, interbedded 

with oolitic limestone. The formation never exceeds 

15 m (49 ft) in thickness and is succeeded by the 

Pickaway Limestone, which has a diverse character 

-sandy and micritic in some parts and oolitic elsewhere, containing fossiliferous beds and an occasional red streak, and marked by stylolites and 

characteristic jointing. Like all Greenbrier subdivisions, the Pickaway thins to the north. 

Above is the notably oolitic Union Limestone. It is 

very fossiliferous, and in the middle it is somewhat 

shaly (red). Both massive and lenticular beds have 

been reported. The clastic Greenville Shale may or 

may not be present on to·p of the Union; it is dark 

or black, calcareous, and lenticular. The highest 
D16 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Greenbrier formation is the sandy and oolitic Alderson Limestone. 

In Randolph County, the Greenbrier Group 

changes drastically; it thins to the north, the lower 

formations pinching out; simultaneously, the facies 

change. To the south the limestone generally includes 

more micrite and oolite, whereas the northern 

Greenbrier contains more clastic (though nonoolitic) 

limestone (Leonard, 1968). 

North of central Randolph County, the Greenbrier has not been divided; hence, its rank is reduced to "Greenbrier Limestone." A threefold division is useful, however : ( 1) the basal Loyalhanna 

Member is a crosshedded arenaceous limestone or 

calcareous sandstone, (2) the middle red and green 

shale and siltstone, tentatively equated with the Taggard and Pickaway Formations of the south (Leonard, 1968), intertongue with basal Mauch Chunk 

red beds in Pennsylvania, and (3) the upper, abundantly fossiliferous limestone correlates with the 

Greenbrier Member of the Mauch Chunk Formation 

in Pennsylvania. Lithologic correlation with the 

southern Union and Alderson Formations is questionable. 

The basal member in the north-central West Virginia subsurface is a sandy limes.tone or a calcareous 

sandstone, typically less than 12 m (39 ft) thick; it 

has been dolomitized throughout most of this region 

(Martens and Hoskins, 1948). To the southwest, the 

basal member is generally oolitic. Oolite distribution 

was determined by topographic features on the preGreenbrier erosional surface (Youse, 1964). Anhydrite traces are commonly found in the lowermost 

Greenbrier of the southwestern counties. 

The Greenbrier Group (Formation) extends 

across the State, except for small areas along the 

Ohio River and in most of the eastern panhandle. In 

northern West Virginia, its thickness ranges from 

15 to 30 m ( 49 to 98 ft) , and in the west, from 15 

to 45 m ( 49 to 148 ft) ; it thickens systematically to 

a maximum in Mercer County, 550 m (1,804 ft). 

The upper contact is everywhere gradational with 

the Mauch Chunk Group in outcrop, there being red 

shale in the upper part of the Greenbrier Limestone 

and marine limestone in the lowest Mauch Chunk 

shale. 

MAUCH CHUNK GROUP 

Like other major Mississippian stratigraphic 

units, the Mauch Chunk Group (of prevailing ;red 

and variegated shale) has different characteristics 

in different geographical areas. In the southern 

basin it is a thicker,. more variable group divisible 

into several formations; in the north and northwest 

across the hinge line, it is thinner and more uniform 

(fig. 7). 

In Mercer, Monroe, and Summers Counties, the 

Mauch Chunk Group is almost 1,000 m (3,280 ft) 

thick, and four formations are recognized. These 

units are traced as far north as Randolph County, 

although the total thickness is halved. The lowest 

third of the oldest (Bluefield) formation is gradational with the_ underlying Greenbrier, containing 

interbedded gray and green marine shale and limestone and minor amounts of terrestrial shaie and 

sandstone. An important member, relatively thin 

but areally extensive, is the Reynolds. Limestone. 

The upper part of the Bluefield contains terrestrial 

shale and sandstone, mostly red, and some coal and 

marine and freshwater limestone. 

The overlying Hinton Formation is composed of 

interbedded red, arenaceous, partly calcareous shale 

and siltstone; ferruginous and calcareous sandstone; 

many fossiliferous limestone beds ; and coal and associated underclay. One significant member is the 

Avis Limestone, which, like the Reynolds, resembles 

the Greenbrier in lithology and faunal assemblage. 

The overlying co~rse-grained, pebbly, crossbedded 

Princeton Sandstone reportedly contains shale and 

plant fossils. The thickness of this littoral deposit, 

6 to 24m (20 to 79ft), varies erratically across the 

southern outcrops. 

The youngest formation, the Bluestone (named 

for the river in Mercer County), is· similar to the 

lowest two Mauch Chunk formations, consisting of 

red and green calcareous shale and siltstone, variegated sandstone, shaly and lenticular limestone, and 

coal and underclay. Like the Bluefield and Hinton, 

the Bluestone yields both plant and marine fossils 

and represents coastal-plain sedim·entation. 

North of central Randolph County, undifferentiated red and green shale .interbedded with green 

flaggy sandstone is termed the Mauch Ohunk Formation. Thin marine limestone is present near the 

base. Coal in the northern counties is absent, even 

though the formation is largely of continental 

origin. Only sparse plant fossils have been noted. A 

local conglomerate in Tucker ·County has been 

labeled the Princeton Member. 

In West Virginia's subsurface, the Mauch Chunk 

Formation thins westward from 90 m (~95 ft) in 

the central part of the State to nothing in Ritchie 

and Wood Counties. Overall, such drastic thinning 

is due to (1) the erosional unconformity at the top 

of the Mississippian System and (2) the increased 

distance from the southeastern source of Mississip-
WEST VIRGINIA AND MARYLAND D17 

pian clastic materials (Dennison and Wheeler, 

1975). 

BIOSTRATIGRAPHY AND PALEONTOLOGY 

Very little study has been made of Mississippian 

biostratigraphy (fig. 1) and paleontology in the 

State since 1950. Most recent papers merely restate 

age relationships published in older reports. 

INVERTEBRATE 

On the basis of marine invertebrates, Dally 

(1956) concluded that the Pocono Formation of the 

south ranges from the lower Kinderhookian Series 

through upper Osagean. Simulrtaneously, the last 

Devonian Hampshire (Catskill) red beds were being 

deposited to the north. The marine invertebrate 

fauna to the north is late Osagean through Merame-. 

cian (Dally, 1956), noticeably younger than the 

southern Pocono fauna. 

The Maccrady Formation has traditionally been 

considered late Osagean to early Meramecian, but 

Dally ( 1956) thought the entire Maccrady to be 

early Meramecian. 

Preliminary conodont biostratigraphy (Chaplin, 

1971) shows that the Hillsdale Limestone, lowest 

formation of the southern Greenbrier Group, correlates with the middle Meramecian of the type area. 

According to Wells ( 1950), the Hillsdale and Denmar Formations are middle and late Meramecian, 

respectively, whereas the Taggard Formation straddles the Meramecian-Chesterian boundary. The 

Pickaway and Union Limestones contain an early 

Chesterian fauna (Hickman, 1951). The Greenbrier 

Formation appears to be younger to the north, that 

is, entirely Chesterian. A hite Chesterian pelecypod 

and endothyroid foraminiferal fauna was identified 

from the upper Greenbrier Limestone in Monongalia 

County (Wray, 1952). On the other hand, Uttley 

( 197 4) put the lower Loyalhanna Member of northern West Virginia and Pennsylvania in the Meramecian because of the contained conodont elements. 

He believed that the rest of the Greenbrier Limestone was Chesterian. 

The Mauch Chunk, then, is middle to late Chesterian. Middle Chesterian conodonts were recovered 

from the Bluefield Formation by Rexroad and Clarke 

(1960). In southern West Virginia, Englund and 

others (1976) reported a (late?) Chesterian marine 

invertebrate fauna from a calcareous siltstone near 

the top of the Bluestone Formation ; the overlying 

member of shale and siltstone (also of the Bluestone) intertongues with the Pennsylvanian Pottsville Group. In Mercer County, where the Mississippian-Pennsylvanian contact is gradational, the 

uppermost Mauch Chunk beds (perhaps 15m, 49ft) 

are of Pennsylvanian age. 

VERTEBRATE 

Carboniferous vertebrate biostratigraphy is an 

uncertain art at best, made difficult by scarce material, consisting principally of isolated chondrichthyan teeth and scales. Ample evidence exists that 

most Carboniferous chondrichthyans, particularly 

among the bradyodonts, had heterodont dentitions, 

but articulated dentitions with associations of tooth 

"species" are very rare. 

Extensive early work, but no recent revision, has 

been done on the lower Carboniferous of the central 

United States (Newberry and Worthen, 1866; St. 

John and Worthen, 1875, 1883) and Europe (Davis, 

1883 ; Woodward, 1889) . 

Early Carboniferous vertebrates from West Virginia are particularly scarce. The area's geologic 

setting is at the interface between the midcontinental seas and the fluviatile environment of the 

rising Appalachian mountains, as well as at the 

junction between the northeastern and southeastern 

United States Carboniferous coal basins. 

At a time when the vertebrate record could provide vital evidence in the study of plate tectonics, it 

is embarrassing that we know nothing whatsoever 

about a region of undeformed sediments across the 

center of the possible dispersal route among European, North American, and Gondwanaland faunas. 

The following discussion is based of necessity 

upon limited collections in the Carnegie Museum, 

Pittsburgh, Pa. 

Marine.-The basal Mississippian Pocono Group 

and Maccrady Formation have yielded only occasional unidentified bone and scale fragments. However, the Greenbrier Group contains useful fossils. 

Two chondrichthyan teeth, a petalodont and an 

orodont, have been found in Benedict's Cave, 

Greenbrier County. Neither can be presently identified to genus. Isolated fish teeth and spines become 

rarer southward. The spine, Physonemus falcatus 

(St. John and Worthen, 1883), from about 27m (90 

ft) below the top of the Greenbrier in the Acme 

quarries at Alderson, and the tooth, Poecilodus st. 

ludovicii (St. John and Worthen, 1883) , from the 

top of the Greenbrier at the Savannah Lane quarries, Lewisburg, are both named from the type St. 

Louis limestone. P hysonemus jalcatus is abundant 

in the upper Chesterian Bear limestone of Montana, 

and Poecilodus ranges into the Pennsylvanian (St. 

John and Worthen, 1883). 
D18 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

The Greenbrier at the Lake Lynn quarry, Fayette 

County, Pa., yields acanthodian and petalodontiform 

denticles and a variety of teeth. These are the elasmobranchs Cladodus sp. and Hybocladodus sp. (midCarboniferous), the bradyodonts Venustodus argutus (Chesterian), V. leidyi (also from the type St. 

Louis limestone), V. variabilis (also Burlington 

limestone of Iowa), Psephodus crenulatus (found 

in the Keokuk limestone), P. Concolutus (Burlington limestone), and Helodus-like anterior cochliodont teeth. The orodont Desmiodus tumidus is 

known from the Loyalhanna limestone (at Breakneck, Fayette County, Pa.) and the St. Louis limestone, and th~ acanthodian Gyracanthus is present 

in the Greenbrier of Uniontown, Pa., plus the rest 

of the world. 

At present, we have little basis for faunal differentiation between Meramecian and Chesterian vertebrates, either in the upper Greenbrier or elsewhere. Possibly, if additional prospecting is car~ 

ried out, the lower Greenbrier of southern West Virginia might yield a conspicuously different fauna. 

Non marine.-The earliest nonmarine West Virginia Mississippian vertebrates are in the Bickett 

shale, Bluefield Formation, Mauch Chunk Group of 

Greer, Monongalia County. The anthracosaurian 

amphibian Pr·oterogyrinus scheelei (Romer, 1970) 

( = M auchchunkia bas sa, Hotton, 1970; see Panchen, 

1975) and the temnospondylous amphibian Greererpeton burkemorani (Romer, 1969) occur with the 

lungfish Tranodis cas{rensis (Thomson, 1965). 

The fauna is similar to that of the British Upper 

Visean Oil Shale Group (Panchen, 1973, 1975); 

Tranodis also oc'curs in the type Chesterian. Bone 

fragments are not uncommon from the Bluefield 

Formation elsewhere in northern West Virginia. 

Fragmentary fish and amphibians have been found 

in the Hinton formation, Mauch Chunk Group 

(Romer, 1941; Panchen, 1967). 

PALEOBOTANY 

HISTORY OF STUDY 

William B. Rogers was the first professional geologist to study the upper Paleozoic rocks of the area 

(1835-41). Although his classification was based 

solely on physical stratigraphy, tempered with economics (Rogers, 1884), he did mention several fossiliferous horizons. The first article on the area's 

fossil plants was published by two medical doctors 

(Hildreth and Morton, 1835) at about the same time 

as Rogers' first report (Gillespie and Latimer, 

1961). In the early-to-middle 1850's, Lesquereux 

collected in the Ohio and Kanawha Valleys; he also 

studied and described Hildreth's and other collections (Lesquereux, 1858), which he later included 

in his several-volume summary (Lesquereux, 1880-

84). This work also included the first attempt in 

North America to use plant fossils biostratigraphically. Fontaine and White (1880), in their volume 

on West Virginia and Pennsylvania Dunkard floras, 

suggested that Permian rocks might be present, thus 

initiating a controversy that still is not settled (Barlow, 1975). 

Many of David White's pioneering studies (middle 1880's and later) were based on fieldwork in 

West Virginia. He (White, 1913, 1936) and Darrah 

(1934) suggested that at least part of the European 

and Appalachian upper Paleozoic geologic columns 

were roughly correlative in detail. Jongmans and 

others (1937, both papers), after collecting in West 

Virginia in the early 1930's, and Bertrand (1939), 

after collecting in Pennsylvania at about the same 

time, agreed with White. As the result of an extensive collecting trip in 1956, Bode (1958) concluded 

that the similarities between European and American floras were much greater than the differenc~. 

Read and Mamay (1964) established a comprehensive zonation of North American Carboniferous 

and Permian floras, and Darrah ( 1969) reviewed 

the American literature and summarized his extensive personal observations. Remy and Remy (1977) 

reviewed the literature on North American late 

Paleozoic floras and compared the results with their 

version of the European late Paleo.zoic. The latest 

studies have been made in conjunction with the U.S. 

Geological Survey's Pennsylvanian System Stratotype program (Gillespie and Pfefferkorn, 1976, 

1977; Pfefferkorn and Gillespie, 1977a, b, c). We 

have known for years that the great majority of 

genera and many species of Carboniferous and 

Permian plant compressions are common to Europe 

and North America. However, the lack of a readily 

available, comprehensive, up-to-date reference has 

resulted in misunderstandings and a lack of attention to floral characterization o.f chronostratigraphic 

divisions. 

Also, the rarity of Appalachian upper Paleozoic 

marine horizons has led to correlation problems with 

the type Permian. Wagner'.s (1974) work in Spain 

on the upper Carboniferous indicates a marine invertebrrute/plant compression/palynological West 

European-Russian correlation. It may be possible to 

extend the results to the American midcontinent 

using marine faunas, and then to the Ap,palachians 

using compression and palynological floras found in 

terrestrial sediments. This correlation should resolve 
WEST VIRGINIA AND MARYLAND D19 

whether the Autuniun is late Carboniferous or Permian (Havlena, 1975) and, therefore, whether Permian sediments exist in the Appalachians·. 

The Amerosinian Megaprovince's remarkable 

similarities probably begin with the Late Devonian 

Archaeopteris and Rhacophyton floras. These -Similarities continue through the late Paleozoic, culminating with the latest Dunkard floras-Late 

Pennsylvanian or Early Permian. 

MISSISSIPPIAN FLORA 

In West Virginia, the Early Mississippian or Pocono flora is characterized by Lepidodendropsis 

(Read, 1955). In ·basal units, Adiantites and Rhodea 

are the most commonly associated plants. Adiantites 

is replaced by Triphyllopteris in the upper Pocono. 

Plant fossils are scarce in the Maccrady and marine 

Greenbrier, although shaly lenses in the upper 

Greenbrier and Mauch Chunk (Upper Mississippian) usually contain Fryopsis, Cardiopteridium, 

fragmented stems, and megaspore ·clusters. The upper Mauch Chunk is characterized by a consistently 

oc·curring flora dominated by Stigmaria stellata, 

Sphenopteri.s elegans, and Sphenophyllum tenerrimum. This flora, also present in several other Eastern and Midwestern States, is characteristic of the 

Namurian A. 

Thus, the major difference between the European 

lower and upper Carboniferous and the North 

American Mississippian and Pennsylvanian is the 

Namurian A, located at the base of the European 

upper Carboniferous and at the top of the North 

American Mississippian (White, 1936; Gillespie and 

Pfefferkorn, 1977). 

PENNSYLVANIAN AND PERMiAN SYSTEMS 

LITHOSTRATIGRAPHY 

A general map (fig. 8), four ·cross sections, and 

two classifications with an incomplete plethora of 

stratigraphically arranged names, support this discussion of a thick diverse rock section. The cross 

sections (figs. 9, 11) show representative highly 

repetitious assem:blages of strata typical of the 

Pennsylvanian and Permian. Selected coals (from a 

list of 117) , a few limestones, argillaceous beds, and 

sandstones are included in the classifications (figs. 

10, 12). Sandstones are found dose above most coals, 

and, except for the Pocahontas-New River sandstone, each sandstone assumes the name of the underlying. coal (unless an earlier name has preference, or a special depositional situation exists). 

The area of Pennsylvanian-Permian strata is 

arbitrarily divided into the "older mining district" 

and the "younger :mining district" (fig. 8). The 

older mining district conforms to an east-northeasttrending geologically older coal basin in southern 

West Virginia (which swings southwest to include 

strata in eastern Kentucky, western Virginia, central Tennessee, and northwestern Alabama) . The 

younger mining district generally conforms to a 

north-northeast-trending geologically younger coal 

basin in northern West Virginia, western Marytand, 

southwestern Pennsylvania, eastern Ohio, and northeastern Kentucky (Arkle, 1974, p. 9). 

On the east in the Allegheny Mountain Section 

(fig. 2), the Pottsville Group cons:ists of much quartzose sandstone, some subgraywacke, argillaceous 

beds, and irregular thin coal beds; subdivision is 

difficult. As the unit thickens to the south-southeast, 

the quartzose sandstones are confined to upper beds 

or thin to·ward southeasternmost exposures; they 

disappear to the southwest in the State's central 

Upshur and Webster Counties. The westerly disappearance of the quartzose sandstones trends north in 

the subsurface into Pennsylvania. On exposures in 

southeastern West Virginia, Allegheny and Conemaugh strata thin perceptibly, change facies, and 

lose coals. 

The Pottsville Group is composed orf subgraywacke and argillaceous beds above an irregular Mississippian surface north of the 61-m (200-ft) 

isopach in the subsurface of Mason, Wood, and 

Pleasants Counties of north-central West Virginia 

(fig. 8). From here, the Pottsville section thickens 

rapidly to the south-southeast in southwestern. West 

Virginia, and the Allegheny Formation loses identity 

below Conemaugh red beds. The lithologic characteristics of the subsurface section, based on limited 

data, are a thin replica of the thickening exposed 

section to the south. 

OLDER MINING DISTRICT 

Sediments from a southerly source were deposited 

in a rapidly !but intermittently subsiding basin in 

southern West Virginia. Little paleogeographic 

change took place during Mississippian and early 

Pennsylvanian time. Source materials. became 

coarser and more abundant, and the paleoclimate 

fostered extensive flora growth and plant-debris 

preservation in a chemically reducing environment 

d~ring deposition. 

The district includes the Pocahontas, New River, 

and Kanawha Formations and the Charleston Sandstone Group; these units have a ·maximum cumula-
D20 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

LANATIO;N 

Area of the 

younger 

mining district 

==C> 

Trend of the 

younger 

coal basin 

--67m--

61-Meter (200 Foot) 

Isopach of the 

PotlsvUie Group 

Direction - of 

thickening 

of the 

Potlsville 

Group 

00000 

Western hmit of 

Upper PotlsvUie 

quartzose 

sandstones 

DODO 

Southwest limit 

of major 

coal 

production 

• 

, 

, 

•• •• 

Mining 

district 

boundary 

Area of the 

older Trend of the 

older 

~ 

~ 

Coal production, by county 

907,185 metric tons 

(1,000,000 short tons) 

or more, 1976 

/ 

, 

' 

mining district coal basin 

D~ D' 

50 MU.ES 

.. -E,~--~~----C31~~ 0 50 KU.OMETERS 

FIGURE 8.-Basin trends and coal-mining features of Pennsylvanian-Permian strata in West Virginia and Maryland. 

tive thickness of about 1,326 m ( 4,350 ft) . (The 

older term "Charleston Sandstone Group" (Campbell, 1901, p. 5) informally describes the lithostratigraphy without regard to time-rock relationships, 

which are currently being studied by the USGS in 

connection with the stratotype section project for 

the Ninth International Carboniferous Congress.) 

The younger mining district of northern and western West Virginia includes the Pottsville, Allegheny, 

Conemaugh, Monongahela, and Dunkard Groups; 

these units have a maximum cumulative thickness of 

about 914 m (3,000 ft) (fig. 1). Strata of the upper 

Pottsville, Allegheny, and possibly the lower Conemaugh to the north have a facies relationship with 

the essentially subgraywacke Charleston Sandstone 

Group sequence to the south. 

The boundary between mining districts is the surface expression of an atypical north-northwestthinning section of the older mining district, subjacent to the east-southeast-thinning of an atypical 

section of the younger mining district. In the north, 

the division is the base of the upper Pottsville 

quartzose sandstones; farther southwest, it is the 

Conemaugh red-beds base and the top of the 

Charleston Sandstone Group. 

The Pottsville· Group of the younger mining district was deposited on an irregular Mississippian 

surface and shows a fairly uniform (although vari-
WEST VIRGINIA AND MARYLAND D21 

able) thickness north of the 61-m (200-ft) isopach 

line in northern West Virginia, in western Maryland, and , throughout much o.f the northern remainder of the Appalachian coal field. 

Younger strata of the Pocahontas and New River 

Formations were deposited on an irregular older 

Mississippian surface to the north-northwest (in the 

direction of thinning) . In the subsurface, the New 

River quartzose sandstone facies was deposited on 

an irregular Lower Mississippian. surface on the 

Burning Spring anticline of Pleasants, Wood, and 

Wirt Counties (Flowers, 1956, p. 15). A transition 

zone between Mississippian and Pennsylvanian time 

marks a continuous-deposition area on exposures in 

Mercer and Summers Counties and in the subsurface 

farther north in McDowell, Wyoming, and Raleigh 

Counties (Arkle and Latimer, 1961, p. 121; Englund 

and others, 1977, p. 38, 39). 

The coal-bearing facies of the Pocahontas, New 

River, and Kanawha Formations and the Charleston 

Sandstone Group is exposed ever farther northnorthwest on a broad north-northwest-dipping 

monocline in ascending the section. Major coals have 

formed in narrow linear patterns paralleling the 

east-northeast .basinal trend. They are eroded on 

southeasternmost exposures where many coals ·are 

thickest. Coals of the New River Formation and 

Charleston Sandstone Group thin southeast of their 

maximum development and possibly disappear in 

that direction. All coals thin and disappear in ascending order, farther to the northwest. 

The Kanawha and Charleston Sandstone section 

shows that a back-barrier delta environment during 

Pocahontas and New River time gave way to lower 

and upper delta-plain environments. ·Deposition of 

the Charleston Sandstone Group culminated with 

deposition of deltaic subgraywacke between the No. 

6 Block coal and the base of the Conemaugh redbeds 

(figs. 9 and 10). 

POCAHONTAS FORMATION 

The Pocahontas Formation (fig. 10) includes 

strata from the top of the Mauch Chunk red beds 

and the base of the lo•west Pennsylvanian sandstone 

to the top of the Flattop Mountain sandstones. A 

thickness of 216 m (710 ft) can be seen between 

Pocahontas, Va., and Great Flattop Mountain (at 

the common corner of McDowell and Mercer Counties, W. Va., and Tazewell County, Va.) (White, 

20 Mn.ES SEE FIGURe B FOR LOCATION OF SECTION 

METERS FEET i' 

5000 

1000 

VERTICAL EXAGGERATION X 26.4 

I I 

I 

20 K LOMETERS 

~CHARLESTON; 

I. ... end ofturnpike 

WARFIELD 

ANT1fL1NE 

--r ~sToc~oN-WA---~--~ 

· KANAWHA FORMATION · 

EXPLANATION 

PENNSYLVANIAN AND PERMIAN 

D 

Conemaugh, Monongahela, and Dunkard Groups (undifferentiated) 

Allegheny Fonnatlon 

Sandstone facies of the Charleston 

Sandstone Group 

D 

Coalbea!:tng fades of the Pocahontas, 

New River, and Kanawha Fonnatlons 

and Charleston Sandstone Group 

D . 

. Quartzose sandsfone faCies of the 

Pocahontas and New River Fonnatlons 

~oonfonnity 

BASE OF THE Mali lied from Arlde, 1974, p. 20. Published 

GREENBRIER LIMESTONE with permission of Geological Society of 

America 

MISSISSIPPIAN 

Mauch Chunk Group 

(undifferentiated) 

Greenbrier Group 

(undifferentiated) 

Maccrady Fonnatlon 

(Red Beds) 

FIGURE 9.-Geologic· cross section from the Ohio River to Princeton, W. Va. 
D22 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Conemaugh Group 

Charleston No. 6 Block coal 

Sandstone Upper No. 5 Block coal (North Coalburg) 

Group Lower No. 5 Block coal (No. 5 Block) 

107m HomeWood Sandstone 

(350ft Kanawha Black flint1 

maximum) Stockton coal 

Coalburg coal 

Winifrede coal 

Chilton "A" coal 

Winifrede limestone1 

Chilton coal 

Hernshaw coal 

Dingess coal 

Dingess limestone, 

Seth limestone1 

Kanawha Cedar Grove coal 

Alma coal 

Formation Campbells Creek limestone1 

640m Peerless coal 

(2100 ft Campbells Creek coal 

maximum) 'Powellton coal 

Stockton I imestone2 

Unnamed shale2 

Eagle coal 

Eagle limestone1 

Lower War Eagle coal 

Gilbert shale1 

Gilbert coal 

Douglas coal 

.Douglas sandstone 

Douglas shale2 

Nuttall sandstone 

Skelt shaleZ 

New River Hartrid.ge shale2 

Sewell coal ("Pocahontas No. 12") 

Formation Beckley coal ("Pocahontas No. 11") 

0 to 314m Ouinnimont shale 

(1030 ft) Fire Creek coal ("Pocahontas No. 10") 

Pocahontas No .. 9 coal 

Pineville sandstone 

Pocahontas No. 8 coal 

Flattop Mountain sandstone 

Pocahontas Pocahontas No. 6 coal 

Formation Pocahontas No.4 coal 

Unnamed shale2 

0 to 216m Pocahontas No. 3 coal 

(710ft) North Fork shale2 

Squire Jim coal 

MISSISSIPPIAN SYSTEM 

1Manne 

~Fresh or brackish 

FIGURE 10.-Pennsylvanian System selective classification-older mining district (southern West Virginia). 

1908, p. 13). The form81tion thins rapidly to the 

north-northwest and disappears to the northeast in 

Greenbrier County, W. Va. (fig. 2). 

are present. Penecontemporaneous slumping and 

sedimentary features (such as crosslaminations) 

are common. 

The Pocahontas is ·compo-sed of subgraywacke 

(repetitious, massive, slightly argillaceous, medium 

grained, and locally conglomeratic) and gray to medium-gray shale intercalated with thin impure underclay and coal. Thin sideritic nodules and lenses 

T.hirleen coals have been named; the Squire Jim 

is the thickest of four basal coals. Successive coals 

are the Pocahontas Nos. 1 to 7 ; 3, 4, and 6 are 

commercially important. These coals are generally 

less than 1.8 m (6 ft) thick, although in one area, 
WEST VIRGINIA AND MARYLAND D23 

the Pocahontas No. 3 coal is 3.4-4.5 m (11-15 ft) 

thick. 

Other Pocahontas coals are thinner and more irregular. Most have been surface mined, at least 

locally. The soft bright metallurgical coals, often 

multi bedded, are low volatile ( 13.0 ± percent), low 

sulfur (0.5+ percent), and have high caloric value 

(15,000± Btu). 

NEW RIVER FORMATION 

The New River Formation (fig. 10) includes 

strata from the top of the Flattop Mountain subgraywacke to the top of the quartzose Nuttall sandstone. A thickness of 314 m (1,030 ft) can be seen 

along the New River Gorge of Fayette and Summers 

Counties and on exposures in southern West Virginia (Hennen, 1919, p. 294). In the subsurface to 

the north-northwest, the Pocahontas ( ?) and New 

River Formations are represented by only 106.7 m 

(350ft) of quartzose s·andstone, which thins rapidly 

where it is exposed to the northeast and which loses 

identity farther northwest in Tucker County (fig. 8 

and 11, cross section C-C). 

The formation is composed of subgraywacke (repetitious, massive, slightly argillaceous, medium 

·grained, locally conglomeratic), quartzose sandstone, and gray to medium-gray shale, intercalated 

with thin impure underclay and coal. Siderite nodules and lenses are present. The 1 :1 sandstone/ 

shale ratio increases (in sandstone) perceptibly 

north-northwest. Medium-scale crosslaminations are 

common in quartzose sandstones, which ·are fewer 

and thinner south-southeast from the type locality. 

Sixteen coals are named; successive co·als in the 

basal strata are numbered Pocahontas Nos. 8 and 9 

above the Pocahontas Formation, and miners designate the younger commercial Fire Creek, Beckley, 

and Sewell coals as Pocahontas Nos. 10, 11, and 12, 

respectively. 

The coals' physical and chemical characteristics 

are similar to those of Poc~hontas Formation coals, 

although they are gradationally higher in volatile 

matter. Commercial coals are generally <1.8 m (6 

ft) thick, although the Fire Creek and Beckley coals 

are 2.7 m (9 ft) thick locally. Other thinner, less 

uniform ·coals have heen mined, both underground 

(in the past) and surface (more recently and extensively). The coals are ·soft, ·bright, medium volatile 

( > 18.0 + percent), and low sulfur (0.5 + percent), 

with 14,500 + Btu caloric v·alues. Correlative coals 

are fewer and less uniform in the thinning section 

northeast of Fayette County, where they ·become 

high-volatile and low-sulfur metallurgical coals. 

New River and Pocahontas smokeless coals were 

used in the past on ships because of high ·caloric 

values and freedom from spontaneous combustion. 

They were also used early (1863) for manufacturing weak coke in "beehive" ovens. To enhance coke 

strength, low-medium volatile coals :have been 

blended for many years with more reactive, highvolatile coking coal in byproduct ovens. 

KANAWHA FORMATION AND CHARLESTON SANDSTONE 

GROUP 

The Kanawha Formation (fig. 10) includes strata 

from the top of the Nuttall quartzose sandstone to 

the base of the Stockton coal or, in its absence, the 

overlying Kanawha Black Flint. The Charleston 

Sandstone Group extends upward to the base of the 

Conemaugh Group red beds. 

The Kanawha Formation, 305 m (1,000 ft) thick 

east of the city of Charleston, thickens to more than 

640 m (2,100 ft) on southeastern exposures. The 

section and coals thin on exposur.es toward the 

northeast and lose identity in the subsurface (figs. 

8 and 11, cross section C-C'). 

T·he Charleston Sandstone Group is 107.7 m (350 

ft) thick at Charleston, _.where .basal subgraywacke 

changes to the coal-bearing facies (figs. 9 and 10) 

farther southeast. The unit is traceable to Kentucky 

and loses identity north-northeast in Lewis and 

Webster Counties (fig. 8). 

The Kanawha Formation and Charleston Sandstone Group are complex stratigraphic units, composed of subgraywacke (repetitive, irregular, thin 

to massive beds, locally conglomeratic) and light to 

medium-gray shale/mudstone (1: 1) intercalated 

with thin carbonate strata and 42 multibedded coal 

seams. Above the Winifrede coal, subgraywackes of 

fine to medium-grained sand in a sideritic/argillaceous-mineral matrix :become. medium-grained 

sand in an argillaceous-mineral matrix. The upper 

Kanawha and Charleston sections are principally 

subgraywacke, and the coals are thinner or absent 

as the section passes below drainage on the northwest and on exposures to the southeast ·in Wyoming 

and Mingo Counties. Three lacustrine-brackish and 

six marine limestones, also shale and impure sideritic concentrations, are present below the Winifrede coal. The only exception is the marine Kanawha Black Flint, shale, and siltstone above the 

· Stockton coal. These units occur as thin beds, lenses, 

and concretionary bodies as much as 0.9 m (3 ft) 

thick. Underclays are thin or absent in Kanawha/ 

Charleston strata. 
D24 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Ascending the section, the lower group of 24 coals 

(to above the Cedar Grove) and the upper group of 

18 coals (including the remainder of the Kanawha 

and Charleston coals) are physically transitional.. 

The lower group is 364 m (1,195 ft) thick (maximum), and the upper group is 326 m (1,070 ft) 

thick (maximum). 

Of the lower ·coal group, the 11 coals immediately 

above the Nuttall sandstone are generally minable 

only in the thickest section in Mingo, McDowell, and 

Wyoming Counties. Of these, the Douglas. and Lower 

War Eagle are soft bright. m·edium volatile (26.0 + 

percent) and low sulfur (0.6+ percent), attaining 

minable thicknesses of >0.6 m (2 ft). Locally, the 

sulfur content of the Gilbert and associated coals is 

> 1.0 percent. The remaining 13 coals are bright 

gas-and-coking coals, high volatile (29.0-35.0 percent), sulfur < 1.0 percent (but locally as much as 

2.0 percent), and 14,500 + Btu. The more important 

are the Eagle (No. 1 Gas), Powellton, Cam.pbell 

Creek (No. 2 Gas), Peerless, Alma, and Cedar 

Grove. 

The upper group contains 18 ·coals. The Hernshaw and Chilton are physically transitional between the soft, bright, high-volatile gas coals. (below) and the dull (splint) coal interbedded with 

thin beds of cannel and ordinary blocky-weathering 

bituminous coal (above). The transitional coals are 

chemically similar to those below and above, except 

that sulfur content is < 1.0 to > 3.0 percent. 

The upper group's principal coals are the locally 

thick Winifrede, ·Coalburg, Stockton, and No. 5 

Block, all characterized as high-volatile, low-sulfur 

coals, split into many benches by thin-to-thick shale, 

clay, and bone partings. These steam coals, 0.9-3.6 

m (3-13 ft) thick, resist pulverization from transportation and handling and lose little fuel value in 

storage. They have been marketed as "Kanawha 

Splints." In manufacturing coke, the No. 5 Block 

coal is blended with low-volatile ·coals~ 

YOUNGER MINING DISTRICT 

Sedim.ents from a southerly source were deposited 

in a gently subsiding, north-northeast-trending 

basin in northern West Virginia and western Maryland during Pennsylvanian and Permian times 

(fig. 8). Lacustrine-swamp-deposit thickness and 

development suggest that repetitive-strata-assemblage axes (fig. 11), in ascending order, shifted 

east-southeast from the Durikard basin axis after 

Allegheny time to the Allegheny Mountain section 

(fig. 4) during Conemaugh time. The axes then 

migrated west during the rest of the Paleozoic deposition. The late Dunkard deposition axis coincided 

again with the Dunkard basin axis at the end of late 

Paleozoic time. 

Allegheny, Conemaugh, Monogahela, and Dunkard (Washington and Greene formations) strata 

thin from axes west-northwest into Ohio and eastsoutheast in northern West Virginia and Maryland. 

On southeast exposures, Allegheny coals thin an.d 

disappear in a· facies of gray shale and fine- to 

medium-grained subgraywacke (figs. 8 and 11, cross 

section B-B') . To the southwest, lacustrine and 

marine limestone and coal of the ·Conemaugh and 

younger strata are transitional with red shale, red 

mudstone, and increasing percentages o.f subgraywacke. The transitional facies usually contains thin, 

areally limited coal, irregular lacustrine and marine 

limestone, and shale, intercalated with or associated 

with red shale, mudstone, and subgraywacke (figs. 

8, 9, and 11, and cross section A-A' and D-D'). 

Subgraywackes coales·ce locally in the transitional 

and red facies to form cliffs more than 30 m ( 100 

ft) thick (Arkle, 1959, p. 122). 

A back-barrier environment dominated regionally 

in Pottsville time, giving way to lower and upper 

delta-plain environments as late as early Conemaugh time. Although occasional lacustrine-marine 

and swamp incursions extended south-southwest, 

terrestrial sediments encroached inexorably northnortheast on a broad coastal plain, as can be seen in 

ascending the Conemaugh, Monongahela, and 

Dunkard section. 

POTTSVILLE GROUP 

Lesley ( 1876, p. 222, 224) used the name "Pottsville" for 18 m (59 ft) of white sandstone overlying 

probable Mauch Chunk Umbra! red shale and underlying XIII, the Lo·wer Coal Group (Allegheny 

Formation) in the Boyd's Hill well group near Pittsburgh (fig. 1) .. He (1876, p. 232) coined the term 

Pottsville from a to·wn of the same name in the 

Southern Anthracite ·coal field of eastern Pennsylvania. 

The Pottsville Group (fig. 12) extends from the 

irregular Mississippian surface to the Brookville 

coal and Mt. Savage clay directly overlying the 

Homewood Sandstone. The top of the quartzose 

Homewood sandstone is normally used as the top of 

the Pottsville Group in the area of limited exposures 

in West Virginia (fig. 8), because the Brookville 

coal and Mt. Savage clay are not identified in northern West Virginia. 

Three coals-thin, irregular, and not useful stratigraphically-in the upper 61 m (200 ft) of the 
WEST VlltGINIA AND MARYLAND D25 

EXPlANATION 

BCoal 

Oshale 

~Red ~ shale 

J;: :~·;; : ·j Sandstone 

mLbnestone 

ifj M!Uine fossO 

D 

FEET 

500 

400 

300 

200 

100 

0 

METERS 

100 

0 

SEE FIGURE 8 FOR LOCATIONS OF SECTIONS 

0 I' I I I 

10 KLOMETERS 

I I l 

10 MLES 

c· 

D' 

CEDARVILLE SANDSTONE 

; ..... ···::·.-::.:~·· ·.· ..... 

~nt.~F-~ · • ·· ~PilTSBUBGH .SANDS .•••• •• • • • • ••.•• ••.• ........ ·:: "· •• -

- E4?· .·.:· ·> :·::: =::::: :: .. : :::·.: ....... .'·:'.·: :.:. ·."·.:-::: .. ·.:-~.: .. ~-...... ;.;;15?~ 

PITTSBURGH COAL 

CONEMAUGH:-:-. - • • • • • . • • • • . • ·- • • • • • • • • • • . . • . •• 1 • .. • - ___ _ 

VERTICAL EXAGGER'ATION X 105.6 From Smith ard others (1974, p. 16 ard 20; 1976, p. 24} 

Revised by Thomas. R. Jake 

FIGURE 11.-Cross sections showing rock assemblages of the younger mining district. 

northern West Virginia Pottsville are described in 

the southwestern Pennsylvania Pottsville (figs. 8 

and 11, cross section C-C'). 

ALLEGHENY FORMATION 

H. D. Rogers (1840) described the Allegheny 

series in the Allegheny River valley above Pittsburgh, Pa. Stevens (1873, p·. 15) redefined the Allegheny to include only those strata between the 

top of the Homewood sandstone and the base of the 

Mahoning sandstone (or the top of the Upper Freeport coal). Typical Allegheny strata are exposed 

above drainage in the Allegheny Mountain section of 

West Virginia and Maryland, along the Ohio River 

in Hancock County, on the northern end of the 

Burning Springs anticline of Pleasants and Wood 

counties, and on the Tug Fork River, just below 

Fort Gay, all in West Virginia. The formation is 

46 m (125 ft) thick on southeastern exposures in 

Tucker County, W. Va., more than 61 m (200 ft) 

thick in Maryland, and about 76 m (250 ft) thick 

in Hancock County, W. Va. 

The Allegheny Formation (fig. 12) is a complex 

sequence of lenticular, thin- to massive-bedded subgraywacke and light-gray to gray shale and mudstone, intercalated with irregularly thick, low-duty 

refractory underclay and coal (figs. 8 and 11, cross 

sections B-B' and C-C') . Thick deposits of Lower 

Kittanning and Clarion refractory clay have been 

mined extensively in Hancock County, W. Va. (two 

mines at present), and Allegany County, Md. Subgraywacke is locally quartzose in the Allegheny 

Mountain ·section of West Virginia and Maryland. 

Locally, thin lacustrine limestone underlies the 

Upper Kittanning and younger coal in Preston and 

Hancock Counties, W. Va., and in Maryland. In 
D26 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN TliE UNITED STATES 

Dunkard 

Group 335m+ 

(1100 ft) 

Monongahela 

Group 

7Q-122 m + 

(23Q-400 ft) 

1Marine 

Conemaugh 

Group 

137-259 m 

(450-850 ft) 

Allegheny 

Formation 

3Q-91 m 

( 1 Oo-300 ft) 

Pottsville 

Group 

15(7)-61 m 

(5Q-200 ft) 

.END OF THE LATE PALEOZOIC 

Proctor sandstone 

Windy Gap limestone 

Nineveh coal 

Nineveh limestone 

Jollytown sandstone· 

Jollytown coal 

Hundred sandstone 

Upper Washington limestone 

Lower Marietta sandstone 

Washington ~al 

Waynesburg sandstone 

Cassville shale-Elm Grove limestone 

Waynesburg coal 

Gilboy sandston~ 

Uniontown coal 

Benwood limestone 

Sewickley coal 

Redstone coal 

Rsdstone I imestone 

Upper Pittsburgh sandstone 

Pittsburgh coal 

Lower Pittsburgh sandstone 

Elk lick coal 

Ames limestone1 

Harlem coal 

Saltsburg sandstone 

Woods Run limestone1 

Bakerstown coal 

Pine Creek limestone1 

Buffalo sandstone 

Brush Creek limestone1 

Brush Creek coal 

Mahoning sandstone {Mahoning coal 

Thornton fire clay Uffington shale 

Upper Freeport coal 

Bolivar fire clay 

Upper Freeport sandstone 

lower Freeport coal 

i Upper Kittanning coal 

Washingtonville limestone1 

Middle Kittanning coal 

. Hamden (Columbiana) limestone1 

lower Kittanning coal 

lower Kittanning clay 

Vanport (Ferriferous) limestone1 

Clarion fire clay 

Homewood sandstone 

Mercer coal 

Connoquenessing sandstone 

Sharon sandstone(?) 

MISSISSIPPIAN SYSTEM 

FIGURE 12.-Pennsylvanian and Permian Systems selective classification-younger mining 

district (northern West Virginia and Maryland). 

lower Allegheny strata, a thin local marine zone 

in sandstone is exposed on the Burning Springs 

anticline, and three marine shale horizons are exposed on the Ohio River in Hancock County. 

tensively) in the Allegheny Mountain section. The 

mining section is often thick ( > 2.4 m, 8 ft) . The 

coals are separated into benches by irregular, thin 

to thick partings. West of the Allegheny Mountain 

section, they are blocky weathering, bright, high 

volatile ( >29.0 percent), high sulfur ( >2.0 perThe Lower Kittanning and Upper Freeport coals 

are mined, both underground and surface (more ex-
WEST VIRGINIA AND MARYLAND D27 

cent), and have caloric values of 14,000 + Btu. The 

coals change to medium volatile (20.0-29.0 percent) 

in Tucker County, W. Va., and become low volatile 

( <20.0 percent) locally on exposures in Maryland. 

Locally, the coals are low to medium sulfur ( <1.5 

percent). 

CONEMAUGH GROUP 

Platt (1875, p. 8) named the strata (fig. 12) between the Upper Freeport coal and the base of the 

Pittsburgh coal for the Conemaugh River, a Monongahela tributary. The group thickens from 137 m 

(450 ft) on the Ohio River to 250 m (850 ft) at 

the Maryland-West Virginia boundary in Tucker 

County, W. Va. It thins to 150 m (500 ft) in the 

Barbour-Randolph-Upshur County area, and apparently to 53 m (350 ft) on exposures in Clay, Kanawha, Lincoln, and Wayne Counties, all in West 

Virginia. 

The Conemaugh Group is composed of red or lightgray to gray shale and mudstone, and thin- to 

massive-bedded fine- to medium-grained subgraywacke, intercalated with thin beds of marine and 

lacustrine limestone and thin irregular coals (Allegheny Mountain section excepted). The entire section is transitional, having principally red shale 

and mudstone; the percentage of subgraywackes 

perceptably increases to the southwest. 

Widespread thin marine limestone and associated 

thicker shale were deposited during Brush Creek, 

Pine Creek, Woods Run, and Ames times in the 

lower part of the Conemaugh in western and northern West Virginia. No marine strata are evident on 

exposures in Braxton, Clay, Kanawha, or Lincoln 

Counties (fig. 2). 

The Mahoning and Bakerstown coals, <1.8 m (6 

ft) thick, have been underground mined. The Mahoning, Brush Creek, Bakerstown, Harlem, Elk 

Lick, Little Clarksburg, and Little Pittsburgh coals 

have been surface mined. Conemaugh coals are 

blocky weathering, bright and dull banded, high 

volatile (>35.0 percent), high sulfur (>2.0 percent), and have caloric values of 14,000+ Btu. Volatility decreases to 15.0 percent in the Allegheny 

Mountain section,·where the coals are low to medium 

sulfur. The Bakerstown coal has < 1.0 percent sulfur 

on the Potomac River in Tucker and Grant Counties. 

MONONGAHELA GROUP 

This group best shows the lateral transition from 

terrestrial red beds to lacustrine swamp deposits because of its geographic distribution and the uniformity and thickness of its limestone and coal 

(figs. 8 and 11, cross. section D-D'). 

H. D. Rogers (1840, p. 150) named the strata for 

the Monongahela River where they cropped out 

near Pittsburgh, Pa. Stevenson ( 1873, p. 15) redefined the group to include those strata between 

the base of Pittsburgh coal and Waynesburg sandstone (fig. 12). Fontaine and White (1880, p. 105-

120), describing fossils with Permian affinities in 

the Cassville shale below the Waynesburg sandstone, placed the Pennsylvanian-Permian boundary 

atop the Waynesburg coal. 

The group is 76 m (250 ft) thick on the Ohio 

River, 122 m (400 ft) thick on the Monongahela 

River, and 107 m (350 ft) thick at one locality in 

the Allegheny Mountain section of Maryland. 

The section is composed of gray shale and mudstone, thin- to massive-bedded subgraywacke, lacustrine limestone, and coal. Gray shale and mudstone 

are transitional with red shale and mudstone, and 

subgraywacke increases perceptibly as limestone and 

coal disappear to the southwest (figs. 8 and 11, cross 

section D-D'). The Redstone, Benwood, and Waynesburg thin-bedded lacustrine limestone and associated 

thin mudstone are thick carbonate accumulations. 

The Pittsburgh, Redstone, Sewickley, and Waynesburg coals are widesp·read in the northern part of 

the Dunkard basin. 

The Pittsburgh coal, accounting for about 24 percent of the State's annual production, is thick and 

uniform in the Dunkard basin. Only basal beds of 

the Monongahela Group as high as the Sewickley 

coal are locally present in upland areas. of the Allegheny Mountain section synclines. The mining of a 

large area of thick Pittsburgh coal in Allegany 

County, Md., accounted for the early peak (1907) in 

that State's coal production. The mining section is 

1.5 m (5 ft) thick on the Ohio River, 2.7 m (9 ft) 

thick on the Monongahela River, and 3.6+ m (12 

ft) thick in the Allegheny Mountain section. 

Monongahela Group coals are blocky weathering, 

bright and dull banded. The Pittsburgh and Redstone are high volatile and high sulfur ( >2.0 percent) and have caloric values of 14,000 ± Btu. The 

Redstone is minable only in Barbour, Lewis, and Upshur Counties, in a small area north of Morgantown, 

and in Mason County. In the Allegheny Mountain 

section, and in areas contiguous with the section, 

both coals are locally 1.5 percent .sulfur and of metallurgical grade (fig. 3). 

The Sewickley coal is similar to the older Pittsburgh and Redstone but generally has a higher sui-
D28 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

fur content ( >3.0 percent). The three coals notably 

lack the thick partings prevalent in the Allegheny 

and upper Kanawha. coals. Pittsburgh and Sewickley volatility decreases to 20.0 ± percent in the Allegheny Mountain section. The thick Waynesburg coal 

is broken into 0.6-0.9 m (2-3 ft) benches by thin to 

thick partings. It tends toward high ash ( >8.0 percent) and high sulfur ( >2.0 percent) content. It is 

thickest on the Monongahela River, where it is surface mined, and locally in West Virginia's. northern 

panhandle on the Ohio River. 

DUNKARD GROUP 

The Dunkard Group was described on Dunkard 

Creek, a Monongahela River tributary in southwestern Pennsylvania (White, 1891, p. 22). It extends 

from the top of the Waynesburg coal (fig. 12) to 

above the Windy Gap coal and limestone (which are 

t~e youngest swamp lacustrine deposits of the la.te 

Paleozoic). The Dunkard Group is more than 335 m 

(1,100 ft) thick along the Dunkard basin axis in 

Pennsylvania's southwestern corner and contiguous 

areas 'of West Virginia. In recent years, some have 

placed the base of the Permian at the Washington 

coal, 30-46 m (100-150 ft) above the Dunkard base. 

Sedimentation from at least early Conemaugh time 

continued without interruption to the end of Dunkard deposition. 

The Dunkard section, rarely divisible into Washington and Greene Formations in West Virginia, is 

composed principally of red shale, mudstone, and 

thin- to massive-bedded graywacke. The Waynesburg 

"A" (between the Waynesburg sandstone and Washington coal) and Washington coals are high vola tile, 

high ash, and high sulfur. They are associated with 

gray shale, mudstone,. and lacustrine limestone in 

the basal 30.5-43.7 m (100-150 ft) of the Dunkard 

Group. They are usually present in northern West 

Virginia, but are thickest along the Ohio River in 

one or more benches 0.6-0.9 m (2-3 ft) thick, separated by variable partings. Thin lacustrine limestone, thin coal ( <0.3 m or 1 ft), and associated 

gray beds extend above to the Nineveh limestone 

only in northern West Virginia. Beginning with the 

Nineveh, the high Greene limestone and associated 

coal streaks are exposed in the hilltops along the 

Ohio River, between the area of greatest thickness 

in Pennsylvania and Jackson County, W.Va. 

BIOSTRATIGRAPHY AND PALEONTOLOGY 

INVERTEBRATE 

Marine invertebrate faunas in West Virginia's 

Pennsylvanian rocks are uncommon and, when present, are often composed of long-ranging taxa inappropriate for biostratigraphic work. In addition, the 

bulk of published papers on the State's Pennsylvanian paleontology is still exploratory and largely taxonomic; detailed biostratigraphy is not available. 

The geologically younger mining district in northern and western West Virginia consists of largely 

Middle and Upper Pennsylvanian rocks similar to 

those of surrounding States (figs. 2 and 8). It has 

attracted most researchers because it contains several regional marine intervals and coal of great economic and stratigraphic value. By contrast, the geologically older mining district to the south contains 

a Lower and Middle Pennsylvanian stratigraphic 

s·ection dissimilar to that of the north and is· complex 

lithologically. Although the need is greater in the 

older district, very few researchers have studied 

faunal elements there. 

Older mining district.-The North Fork shale of 

the Pocahontas Formation contains a local brackishmarine fauna (fig. 10) that has been little studied, 

and only long-ranging nondiagnostic taxa have been 

found (Hennen and Gawthrop, 1915). Local brackish-water fossils from the Pocahontas No. 6 coal 

roof shale (Price,- 1916) complete the limited suite . 

of invertebrate fossils from localities in the Pocahontas Formation. 

The New River Formation includes local brackishwater faunas in the roof shales of the Sewell and 

Sewell "B" coals. Durden (1969) placed the Quinnimont shale in the Namurian C (lower Morrowan) 

on the basis of blattoid insect wings. 

The Kanawha Formation contains· several marine 

horizons that have locally abundant, well-preserved 

faunas. As is true of the low·er formations, few 

studies of Kanawha faunas exist, and most are 

necessarily preliminary. Lower marine units-Gilbert shale, Eagle limestone, . Campbell Creek limestone and Seth limestone-have had almost no attentiqn· (Price, 1915, 1916). Cephalopods and crinoids 

(Furnish and Knapp, 1966; Strimple and Knapp, 

1966) place the Dingess and Winifrede limestones 

in the upper Morrowan (Westphalian B) Gastrioceras (cephalopod) zone and the Stereobrachicrinus 

(crinoid) zone. Moore and others (1944) assigned 

the Winifrede limestone to the lower Atokan Mesolobus striatus (brachiopod) zone. Merrill (1973) 

concluded that the Kanawha Black Flint belonged in 

the basal Desmoinesian .Cavusgnathus biofacies of 

the Neognathodus n. sp. B (conondont) zone (upper 

Westphalian B) . 
WEST VIRGINIA AND MARYLAND D29 

Younger m~n~ng district.-Few biostratigraphically useful ~ottsville rocks are found in the younger mining district. Durden (1969) studied blattoid 

wings in shales of the Connoquenessing sandstone, 

dating them as lower Westphalian B (Morrowan). 

Brackish-water faunas, found in several places in 

Pottsville rocks in the Georges Creek-Potomac basin 

(western Maryland and adjacent West Virginia), 

have not been studied. 

Allegheny rocks in the younger mining district 

lack continuous marine marker horizons. The Vanport and Hamden limestones are reported locally in 

northern West Virginia hut not in Maryland. Both 

are ·considered middle Desmoinesian in .surrounding 

S·tates, on the basis of diagnostic foss.ils--cephalopods ( Wellerites zone-Unkelsbay, 1954), fusulinids 

(Fusulina zone----Smyth, 1974), and conodonts 

(Neognathodus roun·dyi zone-Lane and others, 

1971). Insect faunas. from the Georges Creek-Potomac basin (Durden, 1969) show the Parker coal 

(Lower Freeport) to be. lower Westphalian D. 

Lower Conemaugh rocks contain several important marine zones. The Brush Creek and Ames limestones are useful marker horizons, and the Pine 

Creek and Woods Run limestones are locally present. They have not been studied in West Virginia, 

but surrounding States yield excellent faunas. The 

Brush Creek limestone is basal Missourian, evidenced by cephalopods (Eothalassoceras zoneUnklesbay, 1954), fusulinids (Triticites irregularis 

subzone-Smyth, 1974), and conodonts (Spathognathodus cancellosus/ S. elegantulus zone-Lane and 

others, 1971). The Woods Run limestone is middle 

Missourian, evidenced by fusulinid ( Triticites irregularis subzone-Smyth, 197 4) and conodont 

(Spathognathodus excelsu.s/S. gracilus zone-Lane 

and others, 1971) data. The Ames limestone is lowermost Virgilian, from its fusulinid ( Triticites 

cullomanensis subzone-Wilde, 1975) and conodont 

(Spathognathodus elegantulus/S. elongatus zoneLane and others, 1971) fossils. Blattoids (Durden, 

1969) reinforce· this interpretation, together with 

Stephanian A faunas from the Mason coal (below 

the Brush Creek coal) ·and Bakerstown coal, and 

Stephanian C insects from the freshwater Duquesne 

limestone (between the Ames lim.estone and Elk Lick 

coal). 

Neither upper Conemaugh, Monongahela, nor 

Dunkard beds contain marine fossils. This has created ambiguity in Permo-Carboniferous boundary 

placement. Correlation attempts have been made 

using nonmarine invertebrates. Eager (1972) studied upper Monongahela Group freshwater bivalves 

and ·concluded that they were ·more allied to Rotliegendes Permian faunas than to the European 

upper Carboniferous. Durden ( 1975) and Tasch. 

( 1975) contributed findings on Dunkard blattoids 

and estheriids, respectively, both concluding that 

the faunas are distinctively Permian. Indeed, upper 

Dunkard insects are correlative with the Leonardian 

of Texas and New Mexico. 

VERTEBRATE 

Nonmarine Pennsylvanian vertebrates.- West 

Virginia's Pennsylvanian vertebrates are rare and 

little studied. The younger mining district vertebrate record has been explored to a limited extent 

(Lund, 1975, 1976; Olson, 1975), ·but the older mining district is paleontological terra incognita. 

T~he earliest known Pennsylvani·an vertebrates 

from West Virginia occur near Ansted (southeast 

of Charleston) , at about the level of the Lower 

Douglas coal (basal Kanawha Formation, Pottsville 

Group, fig. 10). This is the only known vertebrate 

horizon from the southeastern ·coal ·basin. Investigators to date have uncovered xenacanth shark teeth 

(Xenacanthus sp. cf. X. triodus) and Helodus simplex spines and a dental battery (Bradyodonti: 

Helodontiformes) among .the chondrichthyans, and 

Megalichthyes scales (Rhipidistia) and a trissolepid 

near Sphaerolepis among the bony fishes. 

The H elodus material is the first associated dentition of this species from the Western Hemisphere. 

It was originally reported fro.m Britain's Knowles 

Ironstone (Moy-Thomas, 1936). Isolated teeth have 

been reported through the Dunkard in freshwater 

deposits (Lund, 1975) but are hard to distinguish 

from the helodontiform anterior teeth of various 

cochliodonts (Lund, 1976). 

The sphaerolepid is a mo·rphological predecessor 

orf fish from the Virgilian Birmingham shale of 

Pittsburgh (Lund, 1975). These forms are related 

to but are distinct from Sphaerolepis, from the Upper Pennsylvanian· of Kounova, Bohemia, Czechoslovakia (Gardiner, 1967) . 

The Kounova and Pittsburgh specimens have 

cycloidal scales that have very fine enameloid pectinations and poinh!, w·hereas the headless Ansted 

specimen has the distinctive scales only on the lower 

flank. Nonmarine vertebrate faunas from northern 

West Virginia, southwestern Pennsylvania, and 

eastern Ohio are relatively well known and indicate 

a Virgilian age for rocks from the Conemaugh 

Group above the Mason shale to the lower 'half of 
D30 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

the Monongahela Group (Lund, 1975), correlating 

with European Stephanian faunas. 

Marine Pennsylvanian vertebrates.-The limited 

lower and middle Conemaugth marine fauna ·contains very few identifiable vertebrates. Identifiable 

remains from the Ames limestone (fig. 12) include 

acanthodians : Cladodus sp. ( Chondrichythyes : Elasmobranchii) ; Petalodus ohioensis; J anassa striglina, 11Peltodus" transversus, Peripristis semicircu,.. 

laris (Bradyodonti :Petalodontiformes) ; the orodont 

Chomatodus sp.; the cochliodont Deltodus angularis; 

and Physonemus cf. P. ancinaciformes (incertae 

sedis). Vaugqn (1967) described a vertebrate (in 

certae classis.) found in. .the Ames limestone as well. 

The few useful teeth and spines· (Romer, 1952; 

Baird, 1957) roughly indicate a Late Pennsylvanian 

age, which, surprisingly, agrees with the age of the 

nonmarine vertebrates. A faunal continuity with 

the lower Permian is indicated. 

Nonma1·ine Permian vertebrates.-The Benwood 

limestone (fig. 12) seems to herald a marked, 

though primarily evolutionary ·change in the vertebrate fauna. The larger fossil vertebrates from the 

top o.f the Benwood limestone through the uppermost Greene Formation beds correspond in detail to 

Autuniun European faunas as well as to those from 

the western United States Wolfcamp. The uppermost Greene Formation has possible Leonardian 

faunal affinities (Lund, 1976; Olson, 1975). 

The vertebrates show ·evolutionary continuity 

from the Conemaugh through the Dunkard, changing with depositi9nal environment changes as the 

Pennsylvanian epicontinental sea retreated. There 

are no faunal discontinuities. The vertebrate record 

indicates a Wolfcampian age for the Uniontown, 

Waynesburg, Washington, and Greene formations, 

and a possible Leonardian age for beds roughly 

about the Nineveh limestone and above. The Virgilian-Wolfcampian boundary has been classically 

accepted as the end of the Pennsylvanian (see Introduction and Dunkard Group discussion). 

PALEOBOTANY 

In West Virginia, the Iithostratigraphically 

prescribed Mississippian/Pennsylvanian boundary 

is the base of the Bluestone Formation Upper Member, which intertongues with the basal unit of the 

overlying Pocahontas Formation. The Namurian A 

flora disappears, and the zone o.f N europteris pocQ;-

hontas ·begins in the Upper Member. Consequently, 

the lowermost plant biostratigraphic zone in the 

Pennsylvanian is defined by N. pocahontas, a close 

relative of N. schlehani, the characteristic plant in 

the lowermost upper Carboniferous. of Europe. 

Some taxonomists believe that these plants may be 

varieties of the same species (Williams, 1937; Bode, 

1958). 

Many plant biostratigraphic zones, based on first 

occurrences and concurrent ranges, are now being 

established for the remaining upper Paleozoic sediments. They do not .coincide exactly with established 

lithostratigraphic boundaries. More than 200 floras 

have been collected in West Virginia during the last 

four field seasons by the U.S. Geological Survey's 

Pennsylvanian Stratotype Study. These, along with 

past collections and illustrated reports, indicate that 

the upper Paleozoic rock sequence in West Virginia 

is correlative with similarly aged rocks across the 

United States, and with established Namurian, 

Westphalian, Stephanian, and Autuniun sequences. 

N europteris pocahontas generally characterizes 

basal Pocahontas Formation units. Lygirwpteris 

(ranges of L. stangeri, L. hoeninghausi, and others, 

are not firmly established) begins just below the 

Pocahontas No. 1 coal. M ariopteris eremopteroides 

appears just abo·ve the Pocahontas No. 2 coal. 

Sphenopteris, Calamites, Alethopteris, Lepidodendron, Sphenophyllum, and Asterophyllites species 

form other zones in the Pocahontas, although ranges 

are not completely known. N europteris smithsii, a 

large-pinnuled N. pocahontas variant, and Mariopteris pottsvillea, M. eremopteroides variant, appear 

near the Pocahontas No. 7 coal. 

Important New River Formation additions are 

Alethopteris decurrens near the Beckley coal and 

Sphenophyllum cunei folium, N europteris heterophylla, N. obliqua, and Asterophyllites equisetiformis slightly above the Sewell coal. N. pocahontas 

and N. smithsii disappear near the Sewell B coal. 

The Kanawha Formation base is marked by .the 

appearance of N europteris gig an tea and the end of 

the lyginopterids and Alethopteris decurrens. Other 

important Kanawha plants are Alethopteris lonchitica, Annularia radiata, Sphenophyllum majus, 

S. cuneifolium, and S. emarginatum. N europteris 

scheuchzeri and N. ovata appear near the top. 

In the lower Allegheny Group (fig. 12), several 

species disappear: Alethopteris lonchitica, N europteris obliqua, N. heterophylla, N. gigantea, N. rarinervis, Linopteris spp., Sphenophyllum cuneifolium, 

and S. majus. S. oblongifolium appears, peoopterids 

become more numerous, and Asolanus camptotaenia 

becomes common. The Charleston Group flora is 

similar. Allegheny floras continue through the Cone-
WEST VIRGINIA AND MARYLAND D31 

maugh Group with more Sphenophyllum oblongifolium and increased pecopterid species. 

Near the 'base of the Monongahela Group, the 

following join with N europteris ovata and N. 

scheuchzeri as major species: Alethopteris zeilleri, 

Danaeides emersonii, Lescuropteris moorei, N emejeopteris feminaeformis, Pecopteris unita, P. arborescens, Sphenophyllum longifolium, Callipteridium 

pteridum, and C. gigas. All ·continue well into the 

Dunkard Group. Some occur only rarely. 

At about the upper Washington limestone horizon, undoubted Callipteris conferta is found (Gillespie and ·others, 1975). Fontaine and White 

( 1880) listed this species fro·m the Washington coal 

roof shales in Monongalia County, and Darrah 

(1975) concurred. Bode (1958) .believed it to be a 

different species, probably C. lyratifolia. Others, 

such as Plagiozamites cf. P. planchardi, Walchia, 

and Taeniopteris sp., have been reported from the 

upper ·Conemaugh through the Dunkard (Darrah, 

1975), but they are facies-dependent and exceedingly rare. 

When these data are ·compared with those of the 

European section, several important correlations 

can be made: ( 1) the Namurian A is well defined 

by Stigmaria stellata, Sphenopteris elegans, and 

Sphenophyllum tenerrimum, (2) the Westphalian 

B base is marked by disappearance of the lyginopterids, (3) the Westphalian C is marked by abundance of neuropterids and Alethopteris lonchitica, 

( 4) the Westphalian D is marked by the first appearance of N europteris ovata, and ( 5) the Stephanian is marked ·by the beginning of Sphenop·hyllu~ oblongifolium, Alethopteris zeilleri, N emejeopteris feminaeformis, and Callipteridium gigas. 

The Autuniun begins with the first occurrence of 

Callipteris conferta. 

Several of the historically used biostratigraphic 

boundaries of Europe can be recognized generally in 

West Virginia and across North America. The many 

first-occurrence and concurrent biostratigraphic 

zones being established in West Virginia will 

greatly refine the presenrt knowledge for this 

continent. 

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D32 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

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WEST VIRGINIA AND MARYLAND D33 

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D34 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

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WEST VIRGINIA AND MARYLAND D35 

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The Mississippian and Pennsylvanian 

(Carboniferous) Systems in the United StatesOhio 

By HORACE R. COLLINS 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1110-E 

Prepared in cooperation with the Ohio 

Department of Natural Resources, 

Division of Geological Survey 

Historical review and summary of areal, 

stratigraphic, structural, and 

economic geology of Mississippian 

and Pennsylvanian and Lower 

Permian rocks in Ohio 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1979 

FIGURE 1. 

2. 

3. 

4. 

CONTENTS 

~bstract -----------------------------------------------------------------

Introduction ------------------------------------------------------------- History of classification ------------------------------:---------------------

]dississippian --------------------------------------------------------

Pennsylvanian --------------------------------------------------------

Permian ------------------------------------------------------------- Geologic setting _________________________________ ------ _ ----------------- _ 

Structure ----------------------------------------------------------------

Lith:~:::~~;~~~ Bedford Shale _ ~ ~ ~ ~~ ___________________________ ~ ~= = =~= = == = = = = = = == = = === = == = =========~==== = = = ==== ==== ------- -'-~ ------------ -~-

Berea Sandstone --------------------------------------------------

Sunbury Shale ---------------------------------------------------

Cuyahoga Formation ---------------------------------------------

Logan Formation ------------------------------------------------- ]daxville Limestone ___________________ - __ -------------------------

Pennsylvanian ------------------------------------------------------- Pottsville Group _____________________________ ---------------------

~llegheny Group -------------------------------------------------

Conemaugh Group ------------------------------------------------

]donongahela Group -----------------------------------------------

Dunkard Group --------------------------------------------------

Permian ------------------------------------------------------------- Biostratigraphy ____ · _____________________________________________________ _ 

]dississippian _________________________________________________ -----·--

Bedford Shale ---------------------------------------------------

Berea Sandstone -------------------------------------------------- Sunbury Shale ______________________________ : ___________________ _ 

Cuyahoga Formation ___________________ ----- ___________ -----------

Logan Formation -------------------------------------------------

]daxville Limestone __ ---------------------------------------------

Pennsylvanian -------------------------------------------------------

]darine faunas --------------------------------------------------- Nonmarine faunas (including Permian) ---------------------------- Plants (including Permian) ______________________________________ _ 

Economic products --------------------------------------------------------

Coal ----------------------------------------------------------------

Clay and shale -------------------------------------------------------

Sandstone -----------------------------------------------------------

Oil and gas ----------------------------------------------------------

Limestone ------------------------------------------------~---------­

Ground water --------------------------------------------------------

References cited ----------------------------------------------------------

ILLUSTRATIONS 

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24 

]dap showing extent of Carboniferous rocks of Ohio -------------------------------------------------

]dap showing the location of counties in Ohio --------------------------------------------------------

Generalized stratigraphic column of the Carboniferous section of Ohio ------------------------------

]dap showing extent of proposed facies of the Cuyahoga Formation ----------------------------------

m 

Page 

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3 

5 

6 
IV CONTENTS 

FIGURE 5. 

6. 

7. 

8. 

Map showing extent of proposed facies of the Logan Formation -------------------------------------

Schematic cross section showing thickness changes of Devonian shales in eastern Ohio ----------------

Map .showing general trend of the principal structural features of southeastern Ohio -----------------

Correlation chart showing the relationship of the Carboniferous section of Ohio to the European and U.S. 

Page 

E7 

10 

11 

midcontinent classification --------------------------------------------------------------------- 18 

TABLES 

Page 

TABLE 1. Subdivision of the Cuyahoga Formation proposed by Holden (1942) --------------------------------- E4 

2. Subdivision of the Logan Formation proposed by Holden (1942) ------------------------------------- 8 

3. Basic types of cyclothems in the Pennsylvanian System of Ohio ------------------------------------ 9 

4. Generalized stratigraphic column for the Pottsville Group of Ohio ---------------------------------- 14 

5. Generalized .stratigraphic column for the Allegheny Group of Ohio ----------------------------------- 15 

6. Generalized stratigraphic column for the Conemaugh Group of Ohio --------------------------------- 15 

7. Generalized stratigraphic column for the Monongahela Group of Ohio -------------------------------- 16 

8. Generalized stratigraphic column for the Dunkard Group of Ohio ------------------------------------ 16 
THE MISSISSIPPIAN AND PENNSYLANIAN (CARBONIFEROUS) 

SYSTEMS IN THE UNITED STATES-OHIO 

By HoRACE R. CoLLINS 1 

ABSTRACT 

Carboniferous rocks in Ohio are present at the surface 

over most of the eastern half of the State and have been 

intensively studied for more than 150 years. All Ohio's coal 

and sandstone and most of its clay and shale resources are 

derived from units of this age. Much of the work on the 

Ohio Carboniferous -is oriented toward the economic possibilities of these rocks. The stratigraphic classification of 

the Pennsylvanian (upper Carboniferous) was established 

originally to emphasize the economic importance of the 

subdivisions. 

The Mississippian (lower Carboniferous) is predominantly 

clastic deposits; the Pennsylvanian is a complex repetitive 

sequence of sandstone, mudstone, shale, limestone, coal, and 

clay. The contact between the Mississippian and Pennsylvanian is everywhere marked by a major disconformity. 

Biostratigraphically, the marine carbonate units of both 

the Mississippian and the Pennsylvanian have been zoned 

and correlated with the U.S. midcontinent region on the 

basis of invertebrate microfossils; Pennsylvanian rocks also 

have been zoned and correlated with the northern Appalachian region on the basis of plant macrofossils. Invertebrate macrofossils are important in both regional correlation and age assignment. 

The Carboniferous of Ohio is not structurally complex, 

although important exceptions are found in the southeastern 

part of the State. The contacts with both the underlying 

Devonian and the overlying Permian Systems are gradual 

and are not marked by recognizable disconformities. The 

break between Permian- and Pennsylvanian-age rocks, how- · 

ever, is a controversial matter and is made on the basis of 

paleontology and not lithology. 

INTRODUCTION 

To most present-day workers,. the Carboniferous 

oo Ohio normally includes only the Mississippian and 

Pennsylvanian Systems; however, most authors of 

the middle and late 1800's included roeks now 

classified as Permian (or Permian-Pennsylvanian 

transition) i.n the Carboniferous. Prosser (1905, p. 

2) assigned the Upper Barren Coal-measures to 

the Dunkard Formation and placed the formation 

in the Permian ( ?) System; he did not, however, include the Permian in the Carboniferous. The general 

clas·sification of Devonian, Carboniferous, and Per1 Division Chief and State Geologist, Ohio Department of Natural 

Resources, Division of Geologica] Survey, Columbus, Ohio 43224. 

mian in Ohio has changed little since Prosser's 1905 

revision. A significant name change, however, was 

made in the early 1900's when most American geologists generally accepted the terms Mississippian 

and Pennsylvanian for the now little-used Carboniferous. A brief discussion of the Permian age question and of the rocks traditionally assigned to this 

system will be given later. In following the usual 

practice of Ohio geologists and the current practice 

of the U.S. Geological Survey, I did not include 

Permian rocks in the Carboniferous System. 

Outcrops of Carboniferous-age r-ocks in Ohio are 

confined appro)Cimately to the eastern half of the 

State (fig. 1). Mississippian units crop out along a 

band extending more than 480 km ( 300 mi) from 

AshtaJbula and Trumbull Counties (s·ee fig. 2 for 

county locations) on the northeast, westward to 

Erie and Huron Counties in the north-central part 

of the State, and then southward to Adams and 

Scioto Counties on the Ohio River. The outcrop .belt 

ranges from 8 km ( 5 mi) to slightly more than 80 

km (50 mi) in width. Lamborn and others (1938, 

p. 43) estimated that Mis.sissippian outcrops are 

present over an approximate area of 8,586 mi2 

( 22,238 km2 ) • Except in. the southernmost part of 

the State, outcrops are largely mantled by glacial 

drift. Mississipp-ian rocks dip under cover to the 

south-southeast, where they are overlain by Pennsylvanian-age units. A small area of Mississippianage rocks is present in Fulton, Defiance, and Williams Counties in extreme northwestern Ohio. This 

area is covered by thick glacial drift, and no outcr.ops are known. . 

South o.f Ross County, beyond the glacial boundary, Mississippian exposures are common. Many 

excellent exposures are also found in the narrow 

belt east of the drift limit from Ross County north 

to Holmes County. In the areas covered by glacial 

drift, exposures are less ·common; however, along 

principal streams near the edge of the drift boundary, good outcrops can. ·commonly be found. Away 

from the glacial boundary, where drift is thicker, 

El 
E2 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

0 

0 

W/#}_tennsylvariian and Permian 

lW!& Dunkard Group 

Pennsylvanian 

I Monongahela Group 

Conemaugh Group 

Allegheny Group 

Pottsville Group 

Mississippian 

ITI1J Mississippian undifferentiated 

- Glacial boundary 

50 100 MILES 

50 100 KILOMETERS 

FIGURE 1.-Extent of Carboniferous rocks of Ohio (modified from King and Beikman, 1974). 
OHIO E3 

DlriAP'rCCt: 

VA Ol.( MONtCOWERV 

TRUIIIIIUl\. 

0 10 20 30 40 MILES I I I I I I I I I I I 

10 20 30 40 KILOMETERS 

FIGURE 2.-Location of counties in Ohio. 

bedrock crops can generally be found only along 

major ·strea~s. 

Highway cuts and quarries provide additional 

exposures in areas where glacial drift obscures outcrops. Hyde (1953) and Pepper and others (1954) 

discussed various aspects of middle and Lower Mississipian stratigraphy on a more or less statewide 

basis; their reports are invaluable guides to specific 

outcrops. Szmuc (1970) described the Mississippian 

of northeastern Ohio and gave many section 

localities. 

Pennsylvanian-age rocks lie to the east and south 

of the Mississippian outcrop belt and cover approximfl,tely the easternmost third of the State. Most 

of the Pennsylvanian rocks lie beyond the limit of 

glacial drift; exposures are numerous. Glacial drift 

mantles parts of the section in the northeasternmost counties; however, the drift is relatively thin, 
E4 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

and good ·exposures ~can generally ;be found. Highway cuts in many places provide the best sections 

in the glaciated parts of the system. Active open-pit 

mines generally provide excellent exposure; however, after mining has been completed, rapid modern 

reclamation method:s es·sentially eliminate strip 

mines as stratigraphic .study areas. Denton and 

others (1961) gave many section descriptions and 

localities representative of the Pennsylvanian in 

Ohio; their report is useful as a general guide to the 

system in the State. 

Permian-age rocks cap the Pennsylvanian System in the easibern and southeas.tern ·countie·s of 

Athens, Belmont, Meigs, Monroe, Morgan, Noble, 

and W a.shington. Outcrops of Permian and PermianPennsylvanian transition-age rocks are abundant 

throughout their area of occurrence. The abundance 

of incompetent red mudstone in this part of the 

section, as well as in the underlying Monongahela 

and Conemaugh Groups, leads to a high incidence 

of slumping, which masks many outcrops. Highway cuts, however, particularly along the interstate· 

system, provide excellent exposures. 

The stratigraphic nomenclature used in this p·aper 

has not been reviewed by the ·Geologic Names Committee of the U.S. Geological Survey. The nomenclature used here conforms with the current usage of 

the Ohio Department. of Natural Resources, Division of ·Geological Survey. 

HISTORY OF CLASSIFICATION 

MISSISSIPPIAN 

The present classification (fig. 3) of the Mississip'P'ian System (lower Carboniferous) in Ohio, unlike that of the Pennsylvanian System ( up,per Carboniferous) , was largely developed by geologists 

working principally for the State geological survey. 

In the first annual report of the newly organized 

geological survey, Briggs ( 1838, p. 79-80) introduced the term Waverly sandstone series for all the 

rocks lying above what is now recogniz;ed as the 

Ohio Shale (Devonian) and below a conglomerate 

p·resently known to correlate with the basal Pennsylvani.an ... age Sharon conglomerate. Andrews ( 1871, 

p. 83) named the Upper Mississippian Maxville 

Limestone, which .he described as being discontinuous and lying on the Logan Sandstone group; 

this was the first such usage of Logan in the geological literature of Ohio. Andrews also referred to 

the Logan Sandstone group as the Upp-er Waverly 

group. Newberry (1870, p. 21) listed the principal 

elem·ents of the Waverly group in northern Ohio 

as being, in ascending order, Cleveland Shale, Bedford Shale, Berea Grit, and Cuyahoga Shale." The 

Cleveland Shale was subsequently assigned to the 

underlying Devonian-age Ohio Shale. 

It remained for Hicks ( 1878, p. 216) to describe 

the Sunbury Formation and formally introduce that 

name. Hicks (p. 216-217) introduced also the term 

Black Hand for a thick s·andstone and ·conglomerate 

in the Black Hand gorge on the Licking River. The 

Black Hand sandstone was subsequently made a 

member of the Cuyahoga Formation. 

Althou~h some minor differences existed in the 

terminology and in the precise positions of boundaries, the basic classification of the Mississippian 

section in Ohio was well established by the Jate 

1800's. Prosser (1905, p. 4) listed the accepted 

units, in ascending orde·r, as Bedford Shale; Berea 

Grit, Sunbury Shale; Cuyahoga, Black Hand, and 

Logan Formations; and Maxville Limestone". With 

the exception of the Black Hand Formation, 

Prosser's classification is still valid. 

On the basis of several facies that could be recognized within the unit, Hyde (1915) proposed a 

subdivision of the Cuyahoga Formation. Hyde 

divided the outcrop region into several areas that 

had few lateral changes. and, in general, had vertically uniform lithologies (fig. 4). Each facies, consisting of one to several members (table 1), was 

given a name taken from an area that typified a 

TABLE !.-Subdivision of the Cuyahona Formation proposed 

by Holden {19.1,.2)1 

1. Henley shale facies: 2. Hocking Valley conglomerate 

facies: 

Black Hand conglomHenley shale erate member. 

member. Fairfield sandstone 

3. Granville shale 

facies: 

Black Hand 

siltstone 

member. 

Raccoon shale 

member. 

5. Killbuck shale 

facies: . Black Hand 

shale member. 

Armstrong sandstone 

member. 

Burbank shale 

and sandstone mem- ber. 

member. 

Lithonolis siltstone 

member. 

4. Toboso conO'lomerate facies: 

Black Hand conglomerate member. 

Pleasant Valley shale 

and sandstone 

member. 

6. River Styx sandstone facies: 

Black Hand sandstone 

member. 

Armstrong sandstone 

member. 

Rittman com?.·lomerate submember. 

7. Tinkers Creek shale facies: 

Meadville shale member. 

Sharpsville sandstone member. 

Orangeville shale member. 

Aurora sandstone submember. 

1 Modified by Holden from Hyde (1915). 
OHIO 

SYSTEM GROUP FORMATION OR BED MEMBER 

PERMIAN 

"E Washington (No. 12) coal 

J~z nl 

..lO: 

c: 

~~~ :::::1 

c ~zz 

a:Z<( 

wW> 

o...O... 

Waynesburg (No. 11) coal nl 

Q) 

~ 

nl 

Cl 

c: 

0 

c: 

0 

~ 

Pittsburgh (No. 8) coal 

~ 

Cl 

:::::1 

nl 

z E Ames Limestone 

~ Q) 

c: z 0 

~ u 

...J 

>- Upper Freeport (No.' 7) coal (/) 

z > z c: 

Q) w ~ 0... Cl 

~ 

<( 

Brookville (No. 4) coal 

Q) 

·::; 

II) 

a· 

0... 

...,.._-~ 

~--'"' ..... Sharon Conglomerate ----- ...--......_,. ,.....;;;;.._.:;..;....; -- - - 1-"'"-- _,__ --

Maxville Limestone ----- ~ - - --- f-"'" ---- - - Vinton Sandstone 

Logan Formation Allensville Conglomerate 

Byer Sandstone 

Berne Conglomerate 

z Black Hand Sandstone 

<( Cuyahoga Formation Portsmouth Shale 0::: > 0... "&; Buena Vista Sandstone 

u; Henley Shale (/) > 

nl u; 

(/) ~ 

~ Sunbury Shale 

Berea Sandstone 

Bedford Shale Sagamore Shale 

Euclid Shale 

z 

<( Cleveland Shale z Ohio Shale Chagrin Shale 0 

> Huron Shale w 

c 

FIGURE B.-Generalized stratigraphic column of the Carboniferous section of Ohio (including 

immediately overlying and underlying units) . 

E5 
E6 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

I 

7 \ 

I 

41°;---------------~------------------~-------~ 

I Youngsto ~ 0

Canton 

EXPLANATION 

Facies boundary, dashed 

where inferred 

1 Henley facies 

2 Hocking Valley facies 

3 Granville facies 

4 T oboso facies 

5 Killbuck facies 

6 River Styx facies 

7 Tinkers Creek facies 

0 100 MILES 

r-~~--~~~--L---L---~-----------~ 

0 50 100 KILOMETERS 

FIGURE 4.-Extent of proposed facies of the Cuyahoga Formation; Hocking Valley, Granville, and Toboso facies from 

Hyde, 1915, figure 1; Henley, Killbuck, River Styx, and Tinkers Creek facies from Holden, 1942, figure 2 (modified 

from Wolfe and others, 1962). 
OHIO 

___ 84° ..l.----- ,---- Toledo 

LAKE 

I 

I 

I 

50 100 MILES 

~~~~~-4--~--~---,---------___j 

0 50 100 KILOMETERS 

E7 

I 

0 I Youngst~wn 

cPanton 

EXPLANATION 

Facies boundary 

1 Vanceburg facies 

2 Scioto facies 

3 Pretty Run facies 

FIGURE 5.-Extent of proposed facies of the Logan Fonnation, from Holden, 1942, figure 3 (modified from Wolfe and others, 

1962). 
E8 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

TABLE 2.-Subdivision of the Logan Formation proposed by 

Holden (1942) 

1. Vanceburg siltstone facies: 

Vinton sandstone member. 

Churn Creek siltstone and shale member. 

Vanceburg siltstone member. 

Rarden shale member. 

Buena Vista sandstone member. 

2. Scioto Valley shale facies: 

Vinton sandstone member. 

Portsmouth shale member. 

Buena Vista sandstone member. 

3. Prettv Run sandstone facies: 

Rushville shale member. 

Vinton sandstone member. 

Allensville conglomerate member. 

Byer sandstone member. 

Berne conglomerate member. 

particular facies. Holden (1942), following Hyde's 

original proposal, enlarg-ed and in part modified the 

subdivision of the Cuyahoga and extended the concept into the overlying Logan Formation (fig. 5; 

table 2). 

However, Hyde's and Holden's proposed subdivisions of the Cuyahoga and Logan Formations to 

date have not been widely used. 

PENNSYLVANIAN 

The Pennsylvanian sequence in Ohio has four 

major subdivisions. These. subdivisions were ·established on p~actical rather than lithologic or paleontologic criteria and bas.ically follow the original 

clas:sification established by 'Rogers ( 1858) for 

Pennsylvania. The basis for the subdivisions, as 

Rogers' original names suggest, is the ~elative 

abundance of minable coal. Rogers' units, in ascending order, were Seral Conglom·erate, Lower Productive (Older) Goal Measures, Lower Barren 

(Older) Coal Measures, Upper Productive (Newer) 

Goal Measures. Various geoJogists, working primarily in Pennsylvania, made a number of modifications in the original proposal, and Pros·ser ( 1905) 

adopted for Ohio the names and overall classification accepted a;t that time. In ascending order, the 

units are Pottsville, AUegheny, Conemaugh, and 

Monongahela. These units, which in Ohio have been 

called formations, series, measures, and groups, are 

presently ·considered to be groups. 

The group boundaries as presently used in Ohio 

are : Pottsville--Sharon conglom·erate to the base 

of the BrookviHe (No. 4) coal; Allegheny-base of 

the Brookville coal to top of the Upper Freeport (No. 

7) coal; Conemaugh-top of the Upper Freeport 

coal to the base of the Pittsburgh (No. ·8) coal; 

Monongahela-base of the Pittsburgh coal to the 

top of the Waynesburg (No. 11) coal. The Waynesburg coal marks the base and the Washington (No. 

12) ·coal the top of a Permian-Pennsylvanian transition zone, which includes the lower part of the 

Dunkard Group. Strata above the Washington coal 

include the upper part of the Dunkard, which is 

presently considered to be Permian in age. 

Within the four groups, individual economically 

im·portant and persistent units have been named. 

How~ever, many of these units, considered to be 

beds according to the American Code orf Stratigraphic Nomenclature are, although named, not 

persistent or economically imporlant. 

More than 100 individual beds have been named 

in the Pennsylvanian section of Ohio. (See tables 

4-8.) The large number of named units is related, 

in part, to the early geologic concept that sedim,entary rock units were tabular in nature and could 

correlated over a wide geographic area. This concept was aided in Ohio by the fact that a few Pennsylvanian-age beds do have a reasonably wide areal 

extent and also by the fact that, because of the 

repetitive nature of the sequence, many beds have 

a general although not precise relationship to 

similar beds at different localities. The proliferation of named units was also, in part, a response 

to the need of a growing industrial society to have 

identifying terms to use in the exploration and 

development of the region's mineral resources. 

A second system of classification, proposed by 

Stout ( 1931), was based on lithoJogic and paloontologi~c consideration. Stout noted that a threefold 

division of the Pennsylvanian could be made on the 

basis of whether the calcareous beds were deposited 

under marine or freshwater ·conditions. Stout's 

classification ·consisted of (1) a lower unit encompassing all the rocks from the base of the Sharon 

conglomerate to the base of the Hamden limestone, 

containing marine shale and limestone, (2) a middle 

transitional unit from the base o.f the Hamden to 

the top of the . Skelley limestone, containing both 

marine and freshwater lim·estone, and (3) an upper 

unit from the top of the Skelley limestone to the 

torp of the Waynesburg coal, containing only freshwater limestone. A ·minor change in Stout's boundary between the lower and middle units would be 

needed to accommodate the fact that the type 

Hamden limestone was subsequently shown to be 

nonmarine (Sturgeon and others, 1958). For unknown reasons, possibly entrenchment of the earlier 

system, lack of correlation with the more clastic 

section of neighboring Pennsylvania and West Virginia, or some di·ssatisfaction by the proposer, this 

classification was never adopted. 
OHIO E9 

TABLE 3.-Basic types of cyclothems in the Pennsylvanian 

System of Ohio1 

Lower unit Middle unit Upper unit (transitional) 

1. Clay, nonmarine. Cycle same as 2 Cycle same as 5 

Shale and sand- in lower unit. in middle unit. 

stone, largely 

marine. 

Iron ore, marine. 

Limestone, 

marine. 

Coal, nonmarine. 

2. Clay, nonmarine:~. 4. Clay nonma- 6. Clay nonma- Shale and sand- rine 9

• rine 3

• 

stone, largely Limestone, Limestone 

marine. nonmarine. and calcarLimestone, Shale and eou.s sh.~le, 

marine. sandston.e, nonmarine. 

Coal, nonmarine. partly rna- Coal, nonma ..... rine. rine. 

Limestone, 

marine. 

Coal, nonma- rine. 

3. Clay, nonmarine. 5. Clay, nonma- 7. Clay, nonma- Shale and sanrl- rine. rine. 

stone, probably Limestone, Shale and 

brackish water nonmarine. sandstone, or marine. Shale and nonmarine. 

Shale, fossili- sandstone, Coal, nonma- ferous, brack- nonmarine. rine. 

ish water. Coal, nonmaCoal, nonmarine. rine. 

lFrom Stout, 1931. 

D Commonest cycle in lower unit. 8 Distinctive cycles of the unit in which they occur. 

The cyclical nature of Pennsylvanian strata was 

noted by some early workers, but the concept of the 

cyclothem was proposed and elaborated on by Weller 

(1930, 1931) and Wanles·s and Weller (1932). Stout 

(1931) also recognized cycles in Ohio and described 

s·even basic types (ta:bl.e 3) and their distribution 

within his propos·ed threefold clas,sification of the 

Pennsylvanian section. The concept of the cyclothem 

has been used extensively by most Pennsylvanian 

workers in Ohio and has proved to be an extremely 

v~aluable field tool. A few workers have used cyclothems in a formal stratigraphic sense in reporting 

field investigations. 

More recently, a number of workers have called 

attention to the deltai·c nature of Pennsylvanian 

rocks. The similarities between the sedimentary 

framework of Pennsylvanian rocks in the northern 

Appalachian basin and the sediments of modern 

deltas are .so great that Ferm and Cavaroc (1969) 

used the same terminology for specific recent environments and for ancient environments. No comprehensive classification, however, has been offered 

for the complex ·s·equence of Pennsylvanian rocks on 

the ·basis of deltaic models. 

PERMIAN 

As stated earlier, rocks now .considered to be 

Permian-Pennsylvanian transition in age were, 

prior to 1900, included in the Carboniferous. The 

U.S. ·Geological Survey included the Permian in the 

Carboniferous as late as 1957. Rogers' (1858) Upper 

Barren Measures. was subsequently named the 

Dunkard Series (originally Dunkard Creek Series) 

by White (1891). White placed the lower boundary 

of the Dunkard at the top of the Waynesburg coal 

and included all the overlying .strata in the App~­

lachian region in the Dunkard. Fontaine and White 

( 1880) had previously ·correlated the rocks in this 

interval as Permian in ·age. The break between the 

Pennsylvanian and Permian is not lithologic, but 

rather is bru;ed primarily on the presence o.f Callipteris conferta, considered by many to be an index 

fossil of the Permian. Cross (1958) failed to find 

undisputed Callip·teris conferta below the Washington coal. In November 19-59, members o.f the U.S. 

Geological Survey and the Pennsylvania, Ohio, and 

West Virginia Geological Surveys agreed to consider the Washington Formation (lower Dunkard) 

as Pennsylvanian and Permian in age and the 

Greene Formation (upper Dunkard) as Permian in 

age. Berryhill and .Swanson (1962, p. C43) placed 

the base of the Permian at the base of the W~ashington coal. Rocks between the base o.f the Waynesburg 

coal and the base of the Washington ·coal were 

designated the Waynesburg Formation o.f Pennsylvanian and Permian age. The Waynesburg Formation has not been formally used in Ohio; however, 

the base of the Permian has been acceprted as being 

at the position of the Washington coal (Collins and 

Smith, 1977). 

The lack of a lithologic break in the s·equence 

from basal Conemaugh through the highest rocks in 

the section, a thickness of more than 360 m ( 1,200 

ft) , coupled with only a gradual waning of Pennsylvanian floral types and only generally an increase 

in Permian flora, have led some workers (Gillespie 

and Clendening, 1969; Gillespie and others, 1975; 

Glendening, 1975) to argue for a Pennsylvanian age 

for all rocks no·w classified as Permian. The age 

of the Dunkard is still an enigma. 

GEOLOGIC SETTING 

Basal Missi~ssippian rocks in Ohio are, at the 

surface, everywhere underlain by the Devonian-age 

Ohio Shale. The Ohio Shale in central and southern 

Ohio ·consists of black to brownish-black fissile shale. 

In the northern part of the State, the Ohio Shale 

can be subdivided, in ascending order, into the 
E10 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNPfED STATES 

Eastern Ohio tion is also disconformable, as first noted by Morse 

==--.---------F-o-rm-a---,tio_n_o_r m_e_m_b-er-------, ( 1910) 0 Hyde ( 1953, p. 58) suggested that the "abBerea Sandstone solute range of relief on the pre-Pennsylvania [sic] 

c: 

IU 

·c: 

0 

> CD 

Q 

Bedford Shale 

Huron Shale Member 

Olentangy Shale 

FIGURE 6.-Schematic cross section showing thickness changes 

of Devonian shales in eastern Ohio; lens of siltstone and 

sa'ndstone shown represents the occurrence of these clastic 

rocks in several stratigraphic positions within the Chagrin 

Shale Member of the Ohio Shale as far west as Guernsey 

County (modified from Janssens and de Witt, 1976). 

Huron, Chagrin, and Cleveland Shale Members. The 

Cleveland Member is a predominantly black bituminous shale containing intercalated beds of gray 

shale and siltstone of the inte~rfingering Chagrin 

Member. The Chagrin Member is composed of gray 

shale and siltstone ·and interfingers to the w·est with 

the Cleveland Member (fig. 6). In northern Ohio 

along Lake Erie to the Ohio-Pennsylvania border, 

the Mississippian Bedford Shale is underlain by the 

Cleveland Member on the west and the Chagrin 

Member on the east. 

The nature of the contact between the Devonian 

and Mississippian has not boon studied in great 

detail; however, little evidence for a major unconformity at this contact is see~. Where adjacent rock 

types are relatively dissimilar (that is, red Bedford 

over black Ohio Shale) the ·contact is .distinct and 

easily identified. However, where the Bedford consists o.f gray shale overlying gray shale and siltstone of the Chagrin shale, the contact is indistinct 

and ·cannot be readily identified; in such areas some 

workers have included the Bedford in the Devonian. 

The contact between the Mississippian and the 

Pennsylvanian is clearly disconformable. The contact :between the upper Mississippian Maxville Limestone and the middle Mississippian Logan Formaerosion surface may amount to 350 or even 400 

fe·et [107 to 122 m] ." Local relief, however, is more 

probably ahout 15 to 23 m (50 to 75 ft). Basal 

Pennsylvanian rocks may rest directly on the Maxville Limestone, the Logan Formation, or even the 

Cuyahoga Formation, depending on the degree of 

post-Mississippian erosion in the area. Pennsylvanian beds in the Pottsville Group as high as·the Massillon sandstone are reported as being in direct contact with the Cuyahoga Formation. 

The contact between the Pennsylvanian and overlying Permian definitely lacks a dear-cut break of 

any type. Rocks presently assigned to the Permian 

and Permian-Pennsylvanian transition are indistinguishable from beds in the underlying Monongahela and Conemaugh Groups, which are considered unquestionably Pennsylvanian in age. 

STRUCTURE 

The Carboniferous rocks of Ohio are not structurally complex ex.cept in the region o.f the Burning 

Springs 3Jnticline, the Cam·bridge arch, and the 

Parkersburg-Lorain syncline, which will be discussed later. Mississippian and Pennsylvanian rocks 

were depo-sited on the west and northwest flank of 

the Pittsburgh-Huntington basin. For the most part, 

units dip gently (0°20') southeast into the· basin, 

but along the northern margin of the basin the dip 

component is southerly; in the southernmost part of 

the State, the dip· is somewhat easterly. This regional 

trend is broken locally by m.inor structures generally considered to be largely penecontemporaneous 

features. Faults are relatively rare and generally 

have displacements of less than 1 m. 

The principal ·structural features affecting Carboniferous rocks in Ohio are the post-Permian-age 

Burning Springs anticline, the Cambridge arch, and 

the Parkersburg-Lo·rain syncline (fig. 7). The 

northernmost part of the Burning Springs anticline 

crosses the Ohio River from West Virginia near 

Newport in Washington County and extends to 

about the Washington-Monroe County line, where 

it disappears on the .surface. The trend of the 

Burning Springs anticline is north-south and follows 

the westward pinchout of the Silurian-age Salina 

F 1 salt. The structure may be the result of imbricate 

thrust faulting caused by termination of the decollement glide zone of a westward-northwestwardmoving thrust sheet (Gwinn, 1964; Rodger:s, 1963; 

Woodward, 1959). 
I ' 

J 

OHIO 

84° -------...1..---- r Toledo 

I 

' I 

0

Canton 

COLUMBUS 

0 50 100 MILES 

~~~~~~~~'---L---LI . I I I ---.------------~1 I 

0 50 100 KILOMETERS 

FIGURE 7.-General trend of the principal structural features of southeastern Ohio. 

Ell 

I 

I 

\ 

I 

0 I 

Youngstown 
El2 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

The Cambridge arch is a prominent structural feature that affects Carboniferous rocks in southeastern 

Ohio. This feature trends northwest-southeast from 

northern Washington County through Cambridge in 

central Guernsey County and into Muskingum County. Mapping by Collins and Smith (1977) in 

Washington County indicates that this feature is 

not, as some workers have suggested, a continuation 

of the Burning Sp·rings anticline. Clifford and Collins (1974) reported that the Cambridge arch follows the pinchout of the Silurian-age Salina E salt; 

east of the pinchout, elevations of the Pittsburgh 

coal are about 91 m (300 ft) higher than those to 

the west. Only a gentle southeastward dip is found 

below the salt. These authors interpreted the structure to be the result of ·movement of a southeastward-thickening block of supra-Salina rocks northwestward along a salt glide plane. A postulated 

nearly vertical tear fault (or series of faults) marks 

the western limit of this movement. 

The Parkersburg-Lorain syncline is a broad 

troughlike structure that trends northwest from 

Washington County to Lorain County. Stout and · 

others (1935, p. 898) considered it to be· "the most 

outstanding structural feature of the eastern half of 

the state * * * which can be traced on surface beds 

from Parkersburg [Wood C~unty, West Virginia] on 

the Ohio River, northwest to Lorain County [Ohio] 

at Lake Erie." Little work beyond that of Stout and 

others has been done on this structural feature, and 

its precise nature remains largely unknown. 

LITHOSTRATIGRAPHY 

MISSISSIPPIAN 

The Mississippian System in Ohio consists of six 

formations, which are, in ascending order, Bedford 

Shale, Berea Sandstone, Sunbury Shale·, Cuyahoga 

Formation, Logan Formation, and Maxville Lime ... 

stone. Thicknesses of the clastic units differ considerably, but average on the outcrop 29, 11, 6, 103, and 

51 m (95, 35, 20, 339, and 166 ft), respectively. The 

Maxville Limestone, because of intensive postMississippian erosion, differs extremely in thickness, 

generally not exceeding 15 meters (50ft) on the outcrop. The stratigraphy of most of these formations 

has been widely studied ; however, the Cuyahoga 

and Logan have undoubtedly received the most attention because of efforts to subdivide these units. 

With the exception of the Maxville Limestone, the 

Mississippian rocks of Ohio form a northwestwardthickening clastic sequence of shale, sandstone, and 

conglomerate. Erosion has everywhere reduced the 

original thickness of the Mississippian; however, as 

much as 305 m (1,000 ft) of clastic strata is reported by Hyde (1927, p. 43) in Vinton County. The 

Maxville Limestone is thickest in the southern part 

of the State and is absent in the northern part, but 

the original thickness trend of the unit is not apparent because of severe erosion, which has completely 

removed the unit in many areas. 

BEDFORD SHALE 

The Bedford Shale, as stated above, rests directly 

on Devonian-age shale and in many places is essentially indistinguishable from the underlying beds. 

The formation takes its name from the town of Bedford in Cuyahoga County. The Bedford in southern 

Ohio consists largely of bluish-gray sandy shale containing, particularly in the upper part, sandstone 

and siltstone. In the central and north-central parts 

of the State, the unit becomes red to reddish brown, 

although bluish-gray shale is also present; the unit 

is also much more argillaceous than it is to the 

south. Both the red and gray shales are used by the 

ceramic industry in Franklin and Delaware Counties. North from Franklin County to Lorain County, 

the amount of red shale increases, and red shale predominates in the north. From Cuyahoga County to 

the Ohio-Pennsylvania line, red shale is largely replaced by gray to blue-gray shale and interbedded 

siltstone. Two such massive siltstone me1nbers in 

Cuyahoga County have been named the Sagamore 

and Euclid siltstones (fig. 3). The Euclid member 

was formerly quarried for flagstone. In extreme 

eastern Ashtabula and Trumbull Counties the Bedford rests on the Cussewago Sandstone, which is the 

basal Mississippian unit in this area. 

BER-EA SANDSTONE 

The Berea Sandstone takes its name from the 

town in Cuyahoga County. This unit as well as the 

underlying Bedford has been described and discussed 

in detail by Pepper and others (1954), who made a 

classic report and an in-depth analysis of these 

units. In southern Ohio, the Berea is rep·resented by 

light-gray to buff siltstone, which in many areas cannot be distinguished from the underlying Bedford. 

From about central Ohio (Franklin County) north 

to the type area. and east to the Pennsylvania-Ohio 

border, the unit consists of fine- to medium-grained 

sandstone. In the north-central part of that area, the 

basal part of the Berea is represented by a massive 

channel sand that reaches a thickness. of more than 

72 m (235 ft) at the Buckeye quarry at South Am-
OHIO E13 

herst, Lorain County (Pepper and others, 1954, p. 

28). In many areas, massive channel sand is overlain by ripple-marked thin-bedded sandstone. 

SUNBURY SHALE 

The Sunbury Shale, which was named for the 

village in Delaware County, consists of thinly bedded fissile carbonaceous black shale. The unit is thin, 

averaging only about 6 m (20ft), but is remarkebly 

persistent and can be traced from the Ohio-Kentucky 

line north to Cuyahoga County. East from Cuyahoga 

County to the Ohio-Pennsylvania line, however, the 

Sunbury cannot be separated from the overlying 

Orangeville shale of the Cuyahoga Formation. 

CUYAHOGA FORMATION 

The Cuyahoga Formation is a thick rather complex sequence of shale, sandstone, and conglomerate. 

The unit takes its name from Cuyahoga County, 

where it was first described. The thickness of the 

unit differs; a maximum of about 190 m (625 ft) 

was reported in the Hocking Valley region by Hyde 

(1915, p. 670). The Henley shale, Buena Vista sandstone, and Portsmouth shale (ascending order) are 

significant members in southern Ohio. The higher 

Black Hand sandstone and Berne conglomerate 

members are widespread in the central part of the 

State. In northern Ohio, the unit is predominantly 

bluish-gray shale. 

LOGAN FORMATION 

The Logan Formation, which was. named for the 

town in Hocking County, marks the top of the clastic part of the Mississippian sequence in Ohio. The 

Logan consists of sandstone, conglomerate, sandy 

shale, and shaly sand. The Byer sandstone, Allensville conglomerate, and Vinton sandstone (ascending 

order) are widely recognized members in the southern ·and south-central parts of the State. The Logan 

extends northward only to about Wayne County and 

is not present in northern or northeastern Ohio. 

conformity and concluded that its relief was rela-

. tively low. The discontinuous nature of the Maxville 

is a reflection of dissection that took place between 

the close of Mississippian deposition and the beginning of Pennsylvanian deposition. Limestone is confined mainly to the area south of a line from Muskingum County to Belmont County. Maxville pebbles, 

however, are incorporated in basal Pennsylvanian 

rocks on the outcrop as far north as Wayne County, 

and Uttley (1974) reported a small area of limestone in Jefferson County. The thickness of the unit 

differs considerably, generally being less than 15 m 

(50 ft) on the outcrop and perhaps reaching as 

much as 59 m (195 ft) in the subsurface. These 

data clearly show that the Maxville once covered a 

much larger area and that the present distribution 

is the result of severe widespread post-Mississippian erosion. 

The possibility has long been recognized that 

rocks correlated with Maxville represented more 

than one correlative stratigraphic and age unit. Uttley (1974), on the basis of a synthesis of ava.ilable 

paleontological and stratigraphic data, suggested 

that the Maxville could be divided into units of formational rank and that it spans both Meramecian 

and Chesterian time. (See fig. 8.) 

PENNSYLVANIAN 

The Pennsylvanian rocks of Ohio are a repetitive 

sequence of lenticular sandstones, mudstones, freshwater and m:arine limestones, clays, and coals, averaging about 335 m (1,100 ft) in thickness. Rapid 

facies changes are the norm, and mos.t beds do not 

have good lateral continuity. Because of the general 

lack of distinctive lithologic or faunal differences 

within any individual group, correlation must be 

made on the basis of gross lithologic characteristics 

and stratigraphic sequence. 

Unlike the underlying Mississippian rocks, the 

Pennsylvanian rocks of Ohio thicken slightly to the 

southeast. Greatest thickness is along the Ohio River 

in Monroe and Washington Counties, where an in~ 

MAXVILLE LIMESTONE crease in thickness of about 67 m (200 ft) more 

The Maxville Lim.estone, named for the village in than the outcrop· average is found. Basal PennsylPerry County, is the only carbonate unit in the vanian units reach as high as the Massillon sandMississippian section of Ohio. The unit is very dis- stone and rest directly on the Maxville Lin1estone, 

continuous on the outcrop 'and only slightly more Logan Formation, or Cuyahoga Formation, dependpersistent in the subsurface. Morse (1910) recog- ing on the depth of the pre-Pennsylvanian erosion. 

nized that the Maxville rested disconformably on Sands!tone ranges from massive to shaly bedded 

the underlying Logan Formation; other workers and from very fine grained to coarse grained and 

have subsequently confirmed this fact. Uttley (1974) conglomeratic. The mineralogic ~composition of sevrev.iewed the existing data on the pre-Ma.xville dis -I eral sandstone units in the Monongahela and Dun-
E14 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

kard Groups ranges from 62 to 90 percent quartz, 2 

to 21 percent clay and silt, 0.1 to 1 percent heavy 

minerals, 2 to 10 percent feldspar, 1 to 8 percent 

mica, and 1 to 9 percent rock fragm.ents (Collins 

and Smith, 1977). The lowest sandstone of the 

Pottsville Group tends to be much cleaner and contains 98 to 99 percent quartz. 

Mudstone units are prominent in the Conemaugh, 

Monongahela, and Dunkard Groups. Mudstone units 

are virtually nonbedded, break with an irregular 

fracture, are generally calcareous and have limy 

nodules, are semiplastic to nonplastic, and consist 

predominantly o.f clay- and silt-size particles. Mudstones are predominantly red or some shade of red, 

and green to greenish-gray mottling is common. 

Such units have been variously called clay-shale, 

shale, marl, and red beds. 

Nonmarine limestones range from light to dark 

gray and are generally cryptocrystalline to very finely crystalline and homogeneous. They normally have 

a relatively high clay content and break down readily 

on weathering. Conglomeratic or brecciated nonmarine limestones, in which both matrix and pebbles 

are composed of similar material, are relatively 

common. 

Marine limestones vary from black to medium 

greenish gray to light gray and are generally me-· 

di urn crystalline to coarsely crystalline. The beds 

range from relatively pure limestone ( > 90 percent 

CaCOa) to calcareous shale. In some areas, the limestones of the Allegheny and Pottsville Groups grade 

into marine flints. 

Clays are present under most coals and are generally illitic, noncalcareous, plastic to ·semiplastic, 

light to dark gray, nonbedded, and in many places 

bear root traces. In the Allegheny and Pottsville 

Groups, much of the clay is a kaolinitic nonplas,tic 

"flint" type. 

Ohio's coal is of high-volatHe bituminous rank, 

and, on an "as received" basis, ranges from about 

5 to 20 percent ash, from 1 to 6 percent sulfur, and 

from 10,000 to 13,000 Btu (British thermal units). 

Coals overlain by marine shale and limestone tend to 

contain more sulfur than those overla,in by nonmarine strata. 

POTTSVILLE GROUP 

The Pottsville is the basal group of the Pennsylvanian System in Ohio. The group averages 78 m 

(256ft) in thickness on the outcrop and consists of 

thick conglomerates, sandstones, and shales, and of 

thin coals, marine limestones, and shales. Stout and 

others (1943, p. 140) estimated that sandstones constitute about 42 percent of the total thickness of the 

group. Very thin iron carbonate or clay ironstone 

beds are associated with many of the marine zones ; 

although no longer of commercial interest, these 

"ores" were the basis for the historically important 

Hanging Rock iron district of southern Ohio and 

northern Kentucky. Non marine limestone is not 

known to be present in this group. 

The named beds in the Pottsville of Ohio number 

26 (table 4). The Sharon conglom·erate, which is 

the lowest significant unit in the group·, is very 

erratic in distribution, having been depos~ted in 

valleys cut in the underlying Mississippian. The 

Sharon is typically composed of clean medium to 

coarse quartz sand or pebbles. This unit's principal I 

area of occurrence is Summit, Portage, Geauga, and 

adjacent counties in northern Ohio. The unit also is 

present in Jackson, Pike, and Scioto Counties to the 

south. The Sharon and the higher Massillon sandstone are both noted for high-purity silica;. both 

units are economically important. The Sharon (No. 

1) and Quakertown (No. 2) coals, which are associated with these units, also tend to· be the Ohio 

coals lowest in sulfur. 

Like the Sharon conglomerate, all beds from the 

base of the Pottsville to the Massi11on sandstone 

were deposited on a rather deeply dissected Mississippian surface and, for that reason, are erratic .in 

occurrence. Above the Massillon sandstone the secTABLE 4.-Generalized stratigraphic column for the Pottsville 

Group of Ohio 

Bed Material 

Homewood ----------------- Shale or sandstone. 

Tionesta No. 3b ------------ Coal, local. 

Upper Mercer, 

Big Red Block ------------ Ore, irregular 

Upper Mercer -------------- Limestone or flint. 

Bedford -------------------- Coal, patchy. Sand Block ----------------- Ore, siliceous, local. 

Upper Mercer No. 3a -------- Coal, local. 

Lower Mercer, 

Little Red Block ---------- Ore, kidney. 

Lower Mercer -------------- Limestone, persistent, marine. 

Middle Mercer -------------- Coal, persistent, thin. 

Flint Ridge ---------------- Coal, thin, local. 

Boggs --------------------- Ore and limestone, marine. 

Lower Mercer No. 3 -------- Coal, persistent, thin. 

Lowellville (Poverty Run) __ Coal, thin, nonpersistent. 

Vandusen ------------------ Limestone, or ore, marine. 

Bear Run ------------------ Coal, local. 

Massillon 

(Connoquenessing) ------- Shale or sandstone. 

Quakertown No. 2 ---------- Coal, patchy. 

Huckleberry ---------------- Coal, thin, local. 

Guinea Fowl --------------- Ore. local. 

Anthony ------------------- Coal, thin. 

Sciotoville ------------------ Clay, flint and plastic. 

Sharon -------------------- Ore, local, marine. 

Sharon No. 1 --------------- Coal, patchy. Sharon -------------------- Conglomerate, patchy. 

Harrison ------------------- Ore, local, impure. 
OHIO E15 

tion becomes more re·gular, but, heeause of rapidly 

changing facies, individual beds are generally difficult to trace· for great lateral distances .. 

ALLEGHENY GROUP 

The Allegheny Group has 32 nam·ed beds (table 

5) averaging about 65 m (212 ft) in thickness, and 

is similar in most respects to the underlying Pottsville Group. A major lithologic difference is the appearance of thin nonmarine limestone in the 

Allegheny Group. The Hamden limestone is the 

lowest freshwater limestone 'in the Pennsylvanian 

of Ohio and appears slightly above the Lower Kittanning (No. 5) coal. This group is of major ecoIllOmic im:portance in the State because of its large 

coal and clay resources and lesser, but important, 

limestone resourc,es. 

CONEMAUGH GROUP 

The Conemaugh, containing 40 named beds (table 

6), is the thickest of the four groups composing the 

Pennsylvanian section. The group averages 122 m 

( 400 ft) on the outcrop. The Conemaugh is virtually 

devoid of major econo·mically important coals. Thick 

sandstones, mudstones, and shales are abundant. Thin 

coals, freshwater and marine limestones, marine 

shales, and clays are also present. Above the Skelley 

TABLE 5.-Generalized stratigraphic column for the Allegheny 

Group of Ohio. 

Bed Material 

Upper Freeport No. 7 ------- Coal, patchy. 

Upper Freeport ------------ Limestone and marly shale. 

Bolivar -------------------- Coal, local, thin. 

Bolivar -------------------- Clay, flint and pla.stic. Upper Freeport ------------ Shale or sandstone. 

Dorr Run ------------------ Shale, marine, local. 

Lower Freeport (Rogers) ___ Coal, patchy. 

Lower Freeport ------------ Limestone, local. 

Lower Freeport ------------ Shale or sandstone. 

Upper Kittanning ---------- Coal, seldom present. Washingtonville (Yellow 

Kidney ore) -------------- Shale, marine. 

Middle Kittanning No. 6 ____ Coal, persistent. 

Leetonia ------------------- Limestone, local. 

Red Kidney ore ------------- Shale, siliceous. 

Strasburg ------------------ Coal, local. 

Oak Hill ------------------ Clay, flint and plastic. 

Hamden ------------------- Limestone, nonpersistent. 

Columbiana -----·----------- Limestone, marine, local. 

Lower Kittanning No. 5 ____ Coal. 

Lawrence ------------------ Coal, shaly, local. 

Kittanning ----------------- Shale and sandstone. 

Ferriferous ---------------- Ore, irregular. 

Vanport ------------------- Limestone, marine. 

Scrubgrass ----------------- Coal, seldom present. 

Clarion No. 4a ------------- Coal, patchy. 

Canary -------------------- Ore, very local. 

Clarion -------------------- Sandstone, irregular. 

Winters -------------------- Coal, very local. 

Zaleski -------------------- Flint, impure, marine. 

Ogan ---------------------- Coal, local. 

Putnam Hill ---------------- Limestone, marine. 

Brookville No. 4 ------------ Coal, persistent. 

limestone, the section becomes more continental, and 

marine units disappear from the section; Lingula 

specimens, however, are present in a very few localities at the position of the much higher Permian-age 

Washington coal. In general, the freshwater limestones becom.e much thicker in the upper half of the 

group. 

The first •appearance of red coloration in this 

group indicates an important change in Pennsylvanian-a.ge rocks. Red rocks are not present in the 

underlying Pottsville or Allegheny Groups. Red 

mudstones and thinner red shales become quite abundant from about the Anderson coal upward. The 

first occurrence of red strata, however, is normally 

at, or slightly ~above, the Upper Freeport coal. Thus, 

the appearance of red beds is quite useful as a 

general str,atigraphic. marker, particularly in the 

subsurface. 

MONONGAHELA GROUP 

The Monongahela Group, containing 25 named 

beds (table 7), averages 75 m (247 ft) in thickness 

TABLE 6.-Generalized stratigraphic column for the Conemaugh Group of Ohio 

Bed Material 

Upper Pittsburgh ----------- Limestone, irregular. 

Upper Little Pittsburgh ----- Coal, very local. 

Bellaire -------------------- Sandstone, local. 

Lower Little Pittsburgh ----- Coal, seldom present. Summerfield 

(Lower Pittsburgh) ------ Limestone. 

Connellsville --------------- Sandstone, local. 

Clarksburg ----------------- Coal, local. 

Clarksburg ----------------- Limestone and marly shale. 

Morgantown ---------------- Sandstone, local. 

Elk Lick ------------------- Coal, usually wanting. Elk Lick ------------------- Limestone and marly shale. 

Birmingham ---------------- Shale, siliceous. 

Skelley -------------------- Limestone, local, marine. 

Duquesne ------------------ Coal, seldom evident. 

Gaysport ------------------ Limestone, siliceous, marine. 

Ames ---------------------- Limestone, marine. 

Ames ---------------------- Coal, very local. 

Harlem -------------------- Coal, persistent. Rock Riffle ----------------- Limestone, very local. 

Round Knob-Pittsburgh _____ Clay, calcareous. 

Saltzburg ------------------ Sandstone, local. 

Barton -------------------- Coal, local. 

Ewing --------------------- Limestone, ferruginous. 

Cow Run ------------------ Sandstone, local. 

Portersville ---------·------- Limestone, marine. 

Anderson ------------------ Coal, persistent. 

Bloomfield ------------------ Limestone, local. 

Cambridge ----------------- Limestone, marine. 

Wilgus --------------------- Coal, nonpersistent. 

Buffalo -------------------- Shale or sandstone. 

Upper Brush Creek --------- Limestone, marine. 

Upper Brush Creek --------- Coal, local. 

Lower Brush Creek --------- Limestone and shale, marine. 

Lower Brush Creek --------- Coal, local. 

Mason --------------------- Coal, local. 

Upper Mahoningo ----------- Shale or sandstone. 

Mahoning (Groff) ---------- Coal. 

Thornton ------------------ Clay, irregular. Mahoningo ------------------ Limestone, loc·al. 

Lower Mahoning ------------ Shale or sandstone. 
E16 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

and, except for the presence of several commercially 

important coal beds, is very much like the upper half 

of the Conemaugh. Arkle (1959) described three 

facies in the Monongahela Group in the Appalachian 

basin. These facies in the Ohio part of the basin are: 

( 1) a gray facies consisting of many alternating 

thin gray shale and limestone beds and thick coals in 

the northern and central part of the outcrop area, 

(2) a red facies consisting of thin variegated red 

and yellow mudstone and massive sandstone in the 

southeastern part of the State; coal is. lacking or 

much thinner than that in the northern area, and 

(3) a transitional facies consisting of thin impure 

coals, limestones, and variegated red and yellow mudstones in central eastern Ohio tying together the 

northern and southern areas. As stated above, no 

marine units are known in the group. 

DUNKARD GROUP 

As pres·ently interpreted, rocks assignable to the 

Dunkard Group span the Permian-Pennsylvanian 

boundary; for this reason these rocks are discussed 

both here and under the Permian. (See table 8 for 

stratigraphic column.) The Dunkard Group· in Ohio 

averages 191 m (626ft) in thickness on the outcrop 

and, as stated above, has traditionally been assigned 

to the Permian System. Presently, however, the 

rocks from the top of the Monongahela Group 

TAB;LE 7.-Generalized stratigraphic column for the Monongahela Group of Ohio 

Bed Material 

Waynesburg No. 11 --------- Coal, fair purity. 

Gilboy --------------------- Shale and sandstone. 

Little Waynesburg --------- Coal, persistent. 

Waynesburg---------------- Limestone and marly shale. 

Uniontown ----------------- Shale or sandstone·. 

Uniontown No. 10 ---------- Coal. 

Lower Uniontown ----------- Coal, very local. 

Uniontown ----------------- Shale, siliceous, and 

limestone. 

Arnoldsburg ---------------- Sandstone. 

Arnoldsburg---------------- Coal, wanting. 

Arnoldsburg---------------- Limestone and calcareous 

shale. 

Fulton --------------------- Shale, green, or shaly sandstone. 

Benwood ------------------- Coal, very local. 

Benwood ------------------- Limestone and calcareous 

shale. 

Upper Sewickley ------------ Sandstone, local. 

Meigs Creek No. 9 

(Sewickley) -------------- Coal. 

Lower Sewickley ------------ Sandstone. 

Fishpot -------------------- Coal, persistent, thin. 

Fishpot -------------------- Limestone and marly shale. 

Pomeroy (Fishpot) --------- Sandstone. 

Pomeroy (Redstone) ________ Coal, nonpersistent. 

Lower Mehts Creek 

(Lower Sewickley) ------- Coal, local. 

Redstone ------------------- Limestone and marly shale. 

Upper Pittsburgh ----------- Sandstone, local. 

Pittsburgh No. 8 ------------ Coal, persistent. 

(Wayne:Sburg coal) to the base of the Washington 

coal (lower Dunkard) are classified as PermianPennsylvanian in age. The rocks in this interval 

average 33 m (109 ft) and are indistinguishable 

from the underlying Monongahela Group. The age 

assignment for this part of the Dunkard is based 

not on lithology but rather,on the waning of ·a typically Pennsylvanian flora and an increase of a Permian flora. 

PERMIAN 

Following U.S. Geological Survey usage, the 

Dunkard Group in Ohio traditionally has been divided into the Washington and Greene Formations 

The Washington ave·rages 67 m (221 ft) in thickness and the Greene, 123 m (405 ft). No lithologic 

bas'is exists in Ohio for dividing the Dunkard into 

two formations. and, unlike the underlying Pennsylvanian groups, neither is there a p·ractical basis 

(table 8). The fact that undis.puted Callipteris conferta specimens have not been found lower than the 

Washington coal (lower half of the Washington 

Formation) and the generally Permian character 

of the flora iabove the Washington coal form the 

basis for the current classification of these rocks. 

(See discussions of the Permian and Dunkard elsewhere in this paper.) 

The following statement from Stauffer and 

Schroyer ( 1920, p. 15) -provides an apt description 

of the Dunkard in Ohio: 

The Dunkard is a most variable series of rocks. There are 

sandstones, shales, beds of limestone, and coal; in fact it 

TABLE 8.-Generalized stratigraphic column for the Dunkard 

Group of Ohio 

Bed Material 

Gilmore -------------------- Sandstone. 

Do. ---------------------- Limestone, loc·al. 

Nineveh ------------------- Sandstone, local. 

Do. ---------------------- Coal, local, shaly. 

Do. ---------------------- Limestone, irregular. 

Hostetter ------------------ Coal, thin, shaly, local. 

Fish Creek ----------------- Coal, very local. 

Do. ---------------------- Sandstone, local. 

Dunkard ------------------- Coal, local, impure. 

Jollytown ------------------ Sandstone, local. 

Jollytown 'A" -------------- Coal, local, impure Upper Washington -----..,..---- Shale, variable. 

Hundred ------------------- Sandstone, local. 

Upper Marietta ------------ Sandstone. 

Washington "A" ------------ Coal, shaly, local. 

Creston-Reds 

(Little Washington) ______ Limestone. 

Lower Washington ---------- Limestone. 

Lower Marietta ------------ Sandstone,' local. 

Washington ---------------- Coal, shaly. Little Washington ---------- Coal, shalv. 

Mannington ---------------- Sandstone, local. 

Waynesburg "A" ---------_,- Coal. nonpersistent. 

Waynesburg ---------------- Sandstone, rather steady. 

Elm Grove ----------------- Limestone. 

Cassville ------------------- Shale, gray. 
OHIO E17 

includes nearly all the different varieties of sediments from 

coarse sandstone and conglomerate to the finest grained 

shale. These change rather rapidly from one to the other, 

so that it is often impossible to trace a horizon for any 

great distance. And then too, there is considerable similarity 

between a number of beds at different stratigraphic elevations. This is especially true of the shales which are often 

featureless and devoid of any marks whereby they may be 

recognized. Shale is the most abundant rock in the series. 

The higher shales are often red in the northern part of the 

area, while to the south red is the prevailing color of the 

shale throughout the whole series. Selenite crystals are occasionally to be found in these red shales. This is especially 

true in the vicinity of Marietta. Most of the limestones occur 

in the northern part of the area where the sandstones are 

but poorly developed. As the limestones are traced southward 

they pass into calcareous shales which are often full of 

nuggets of lime. Finally these disappear as do also nearly 

all traces of coal beds, and the series becomes one of chiefly 

shale and sandstone. These latter inc·rease materially in importance in the southern part of the Dunkard field. 

The shales referred to by Stauffer and Schroyer 

are, in fact, the mudstones (commonly called red 

beds) described in the lithostratigraphy section. 

BIOSTRATIGRAPHY 

The subdivisions used in the Carboniferous o.f 

Ohto are mainly rock-stratigraphic units and were 

established with little regard for time stratigraphy; 

this is especially true for the Pennsylvanian, where 

the classification is based largely on the relative 

abundance of minable coals. Age correlations have 

been made of the Carboniferous of the northern 

Appalachians, of the American midcontinent region, 

and of the European section (fig. 8). 

The lower Miss,iss:ippian in Ohio is age-correlated 

primarily on the basis of invertebrate macrofossils. 

Floral zones have been established for the Mississippian in the Eastern United States, but plants are 

far too rare in the Ohio section to· be of value. The 

uppermost Mississip-pian (Maxville Limestone) has 

been correlated primarily on the basis of conodonts. 

The Pennsylvanian of Ohio has been correlated 

mainly on the basis of floral zones. and fusulinids. 

MISSISSIPPIAN 

Although locally fossiliferous, the clastic units of 

the Mississippian in Ohio are not known for their 

abundant biota. Marine to brackish-water invertebrate faunas represent the most abundant group of 

fossils ; vertebrate forms and plants are rare·. 

BEDFORD SHALE 

In northern and central Ohio the Bedford Shale 

is fossiliferous in the basal few feet. This zone, 

at the contact with the underlying Cleveland shale 

(Devonian), yields abundant specimens of Lingula 

and Orbiculoidea. Mollusks, particularly bivalves, 

dominate the fauna of the soft gray shale and ironstone concretions of the basal few feet. The large 

spiriferid Syringothyris bedfordensis also is abundant in this zone. 

Very little work has been done on the Bedford 

fauna since the reports of Herrick (1888a, b), 

Girty (1912), Cushing and others (1931), and Hyde 

(1953). 

BEREA SANDSTONE 

Very few fossils have been obtained from the 

Berea in Ohio. Rare fish remains have been reported: chondrichthyan dermal spines referred to 

Ctenacanthus (Newberry, 1889) and most notably 

well-preserved remains of the paleoniscoid 11Palaeoniscum" ( Gonatodus) brainerdi. Newberry reported 

numerous specimens from a now long-abandoned 

quarry at Chagrin Falls (eastern Cuyahoga County) 

(1873) and from Independence (south-central Cuyahoga County) (1889). 

Plant remains, mostly carbonized fragments of 

Annularia, and poorly preserved brachiopods, including Lin_gula melie and Trigonoglossa, have been 

reported (Szmuc, 1970). 

SUNBURY SHALE 

The Sunbury Shale has yielded fish remains and 

a restricted invertebrate assemblage that includes 

the brachiopods Lingula melie and Orbiculoidea 

herzeri, sponge spicules, scolecodonts, conodonts, and 

foraminifers (Szmuc, 1957). Localities in northern 

Ohio have yielded well-preserved, although disarticulated, remains of the shark Stethacanthus. 

CUYAHOGA FORMATION 

Certain members of the Cuyahoga Formation are 

abundantly fossiliferous locally throughout the 

State. In northern Ohio, Szmuc (1957) reported the 

following generic diversity for the Cuyahoga macrofauna: brachiopods, 37; bivalves, 20; gastropods, 9; 

cephalopods, 4; s'ponges, 4 ; anthozoans, 2 ; bryozoans, 5 ; arthropods, 3. The most notably abundant 

and diverse macrofauna is that of the Meadville 

member in the Cuyahoga Valley, particularly in 

Medina County. Szmuc (1970) indicated that the 

Meadville member is the most fossiliferous unit in 

northeastern Ohio, and more than 125 species of 

invertebrates have been reported; most common are 

bryozoans and the brachiopods Unispirifer and 

Ericiatia. Szmuc (1970) summarized the paleon-

. tology of the remaining members of the Cuyahoga 

Formation in northern Ohio. 
E18 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

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-o~ 

c: 0 ·- 0 ~..c: 

:::;;::;; ~~~~~"-4'" 

-

Maxville Limestone 

Maxville 

~ 

Limestone 

Logan Formation 

Cuyahoga Formation 

Sunbury Shale 

Berea Sandstone 

Bedford Shale 

DEVONIAN 

----- -- --- FIGURE 8.-Correlation chart showing the relationship of the Carboniferous section of Ohio 

to the European and U.S. midcontinent classification (modified from Moore and others, 

1944; Weller and others, 1948; Dunbar and others, 1960). 
OHIO E19 

The Cuyahoga fauna of central and southern Ohio 

has been reported upon most ·extensively by Hyde 

(1953), who listed numerous collecting localities. 

Manger (197la) reported upon ammonoid cephalopods from the Cuyahoga of so~thern Ohio. 

The most notable of the many collecting localities 

reported · for the Cuyahoga Formation by Hyde 

(1953), is the Sciotoville Bar locality, a ledge along 

the northeast bank of the Ohio· River in Scioto 

County, Ohio. This classic locality, from which Hyde 

obtained a large part of the fauna Hlustrated in the 

1953 report, has been submerged since 1920 because 

of construction of a lock and dam. Manger (1971b) 

a·ssigned the Sciotoville Bar locality to the upper 

part of the Portsmouth member. 

LOGAN FORMATION 

The fauna of the Logan Formation was described 

by Hyde (1953) and most comprehensively by 

Fagadau (1952). The clastic lithotope of the Logan 

Formation results in differing and, in some places, 

imperfect preservation of the macrofauna; however, 

Fagadau listed the following generic diversity of the 

Logan: bivalves, 22; brachiopods, 20; gastropods, 5; 

coelenterates, 5; ostracods, 2; trilobites, echinoderms, annelids, bryozoans, and scaphopods, 1 genus 

each. 

Fagadau divided the Logan Formation into two 

faunal zones. The lower zone, which includes all 

strata below the Vinton member, is dominated by 

brachiopods, particularly Rhipidomella missouriensis 

var. sulchella, Chonetes cf. C. pulchellus, and Spiriferina depressa; however, the bivalve Allorisma 

winchelli and the gastropods Tropidodiscus cyrtolites, "Worthenia" strigillata, and Platyceras haliotoides are locally abundant. This lower zone of the 

Logan has faunal affinities with the underlying 

Cuyahoga Formation, as indicated by the mutual 

occurrence of 26 o.f the 62 species known from the 

Logan. 

The upper zone of the Logan Formation, which 

includes the Vinton mem.ber, is dominated by brachiopods, of which Dictyoclostus agmenes, Rhipidomella mesiolis, and Rhynchopora cooperensis are 

the most important. Composita and Pugnoides make 

their first appearance in the middle part of this 

zone. Of the 25 species reported from the up·per 

zone, 8 are present in the lower zone and 6 are 

known from the Cuyahoga Formation. 

The Logan Formation is locally fossiliferous 

throughout its area of outcrop; however, the best 

collecting areas are in Licking, Fairfield, Ross and 

Scioto Counties. Fagadau (1952, p. 99) listed 

numerous localities, as did Hyde (1953). 

MAXVILLE LIMESTONE 

The macrofauna of the Maxville Limestone was 

studied by Morse (1910, 1911). Scatterday (1963) 

studied the conodont fauna, which serves as the 

principal basis for correlation of this unit. Of the 

36 Maxville species listed by Morse (1910), 21 are 

mollusks; brachiopods, however are numerically 

dominant. Macrofossils are present throughout the 

Maxville, but they are most abundant, most easily 

obtained, and best preserved in the light-gray calcareous shale units. The massive sublithographic 

beds are seemingly less fossiliferous. 

Numerous Maxville localities are listed by Morse 

(1910, 1911), Scatterday (1963), and Uttley (1974). 

A locality of particular note is the quarry Somerset Lime and Stone, Inc., west of Somerset in Hopewell Township, Perry County, Ohio. 

PENNSYLVANIAN 

The Pennsylvanian biota of Ohio has received 

considerable attention for more than a century, encouraged, in part, by the presence of economically 

valuable mineral deposits in these strata. 

MARINE FAUNAS 

Marine invertebrate faunas of the Pennsylvanian 

have been studied extensively, beginning in Ohio 

with the reports o.f the Ohio Geological Survey 

under the direction of J. S. Ne,wberry (1869-1882). 

Smyth (1957) published on fusulinids, and Mark 

(1912) . and Morningstar (1922) reported on the 

faunas of ·the Conemaugh and Pottsville Groups, 

respectively. More recently, Sturgeon and Hoare 

(1968) wrote the first monagraph on Pennsylvanian 

invertebrate groups in Ohio, a volume on brachiopods. 

Sturgeon and Hoare (1968, p. 12), in reference 

to the brachiopod fauna, indicated that the Ohio 

fauna is slightly less diverse than that of the Western Interior basin ; there are 42 genera and 93 

species and varieties from the Ohio Pennsylvanian 

versus 46 genera and 130 species for the Western 

Interior basin. This reduced diversity for the Appalachian basin is probably evident in other faunal 

groups also. Multiple factors, including less favorable environments and physical barriers to migration into the Appalachian basin, are responsible for 

this reduction in diversity. In addition, an influential factor must be the absence of marine units in 

the upper Conemaugh and Monongahela Groups, 
E20 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

which represent almost all the Virgilian sequence of 

the Western Interior basin (Sturgeon and Hoar·e, 

1968, p. 13). Paleoecology o.f the Pennsylvani_an 

marine faunas and environments have only recently 

received serious investigation. Principal inv·estigators have been Donahue ~and Rollins (1974) and 

their ~students and Ferm ( 1970) and his students. 

In Ohio, 28 marine horizons. of Pennsylvanian age 

have been repo·rted; only about 9 of these, however, 

can be considered important from the .standpoint of 

yielding abundant ·and divers·e faun~ and of being 

widespread. The important units have produced 

faunas that include corals, :bryozoans, fusulinids, 

arthropods, sponges., mollusks, and brachiowds. 

Generally, brachiopods are n umer.lcally dominant; 

however, the molluscan assemblage is more diverse. 

These units and faunas a:re most ·conveniently discus:sed by stratigraphic groups. 

Pottsville Group.-Although 11 marine horizons 

have pvoduced fossils in the Pottsville, the Lower 

and Upper Mercer limestones are most significant. 

Distinctive brachiopods in the Pottsville include 

Cleiothyridina orbicularis var. crassalamellosa; 

Schizophoria resupinoides ?, Rugosochonetes delicatus, Plicochonetes dotus, Desmoinesia mwricatina 

var. missouriensis, Antiquatonia costellata, Juresania nebrascensis var. infiatia, and Krotovia paucispina (.Sturgeon and Hoa:re, 1968). Distinctive 

Pottsville fusulinids are Fusulinella iowensis and F. 

stouti (Smyth, 1957). 

Allegheny Group.-Important marine units in the 

AUegheny Group ·are, in ascending order, Putnam 

Hill limestone, Vanport limestone, Columbiana s~hale, 

and Washingtonville shale. Diagnostic Allegheny 

brachiopods include Composita girtyi, Wellerella 

tetrahedra, Mesolobus mesolobus, M. lioderma, 

Eolissochonetes fragilis, Chonetinella crassiradiata, 

and Reticulatia rugatia (Sturgeon and Hoare, 1968). 

Distinctive fusulinids include W edelcindellina euthysepta, Fusulina carmani, F. serotina, and F. leei 

(Smyth, 1957). 

Conemaugh Group.-The Brush Creek limestone, 

Cambridg·e limestone, and Ames limestone are the 

most important :fossiliferous units in the Conemaugh. Distinctive brachiopods include Derbyia 

parvicostata, W ellerella osagensis, Enteletes hemiplicatus, Orthotetes conemaughensis, Punctospirifer 

kentuckyensis var. amesi, Composita ohioense, C. 

magna, N eo chonetes semiacanthus, N. granulifer, 

Chonetinella alata, C. fiemingi, Hystriculina wabashensis, Pulchratia cf. P. ovalis, P. symmetrica var. 

regularis, Echinaria semipunctata, E. moorei, 

Antiquatonia portlockiana var. c1·assicostata, Retiulatia huecoensis, Juresania nebrascensis v~r. 

pulchra, Linoproductus cf. L. platyumbonus, L. cf. L. 

magnispinus, and L. oklahomae (Sturgeon and· 

Hoare, 1968). Distinctive Conemaugh fusulinids are 

Triticites ohioensis, T. skinneri, and T. cullomensis 

(Smyth, 1957). 

Collecting localities.-Sturgeon and Hoare ( 1968) 

listed 346 localities from which they obtained 30,000 

brachiopod specimens. Most of these localities have 

yielded a diverse assemblage of other invertebrate 

g~oups, and perhaps one-.fourth have produced teeth 

or dermal spines o.f chondrichthyan fish. This locality register is the most comprehensive and up-todate record available for marine Pennsylvanian 

fossils in Ohio. 

NONMARINE FAUNAS (INCLUDING PERMIAN) 

Nonmarine units yield faunas of bivalves, ostracodes, estherids, and vertehl'lates, including paleoniscoid and chondrichthyan fishes and, rarely, amphibians and reptiles. The nonmarine limestones yield 

diminutive ·molluscan faunas, but these units have 

never been ·collected systematically as have the 

·marine horizons; therefore, their faunas are less 

well known. Eagar (1975) collected nonmarine bivalves from units in Ohio, discuss·ed these faunas, 

and made comparison with other nonmarine faunas 

in North America ·and Europe. 

Lo·calities for nonmarine fossils are localized and 

less well known generally than are localities for 

marine units. Deserving of special mention, how-

. ever, is the famous Linton vertebrate locality, at 

the mouth o.f YeHow Creek just south o.f Wellsville, 

section 7, Saline Township, Jefferson County, Ohio. 

A layer of cannel coal, several inches in thickness, 

at the base of the Upper Freeport coal (uppe·rmost 

Allegheny ·Group), has produced ~emains of amphibians, paleoniscoid and chondrichthyan fishes, 

and phyllocarid crustaceans. This fauna has received 

considerabl·e study by many authors, including Newberry (1873, 1875), Cope (1875), Romer (1930, 

1963), Moodie (1909, 1915, 1916), Steen (1931), 

Baird (1964), and Weston (1944). The mine dump 

of the long-abandoned Black Diamond mine still 

yields fos:sils to diligent collectors .. 

The Dunkard Group in Ohio has yielded fragmentary remains of amphibians, reptiles, freshwater ·chondrichthyans, paleoni.scoids, and dipnoans. 

These remains must be conside~ed rare, although the 

total of these specimens indicate·s a di v·erse "lake 

and pond" vertebrate fauna. Olson (1975) and 

Berman -and Berman ( 1975) considered the fauna 

correlative to the classi·c Lower Permian Wichita 
OHIO E21 

and Gle·ar Fo:rk Groups of Texas. These authors and 

Lund (1975) recently summarized the Dunkard 

vertebrate fauna. 

Vertebrate remains appear to be more abundant 

i.n the Washing:ton Formation. Two localities are 

worthy of note. Moren (1952) reported the Cameron locality in section 18, Adams Township, Monroe County, Ohio, and Romer (1952) ·evaluated its 

fauna, which includes pleuracanth teeth, dipnoan 

remains, and the tetrapods Eryops, Diploceraspis, 

Melanothyris, and EdaphosaurttS, among others. The 

Cameron locality yields fossils from a limestone and 

shale sequence about 2 to 3 m (7 to 10 ft) below 

the Waynes~burg "A" coal. Olson (1970) summarized 

information on this locality. 

The most productive vertebrate locality in the 

Dunkard Group of Ohio has been a localized channel 

conglomerate exposed near Belpre, Washington 

County. Thi.s depo·sit lies above the Upper Marietta 

s·andstone near the top of the Washington Formation and has yielded a diver.se, although fragm·entary, vertebrate assemblage. Olson (1970, 1975) 

summarized the fauna o.f the Belpre locality; this 

fauna includes chondrichthyans, dipnonas, pal·eoniscoids, and the tetrapods Eryops, Diploceraspis, 

M egamolgophttS, Diadectes, EdaphosaurttS, and 

Dimetrodon. 

An important nonmarine invertebrate occurrence 

in Belmont County is the presence of Lingula 

permiana in a shale parting of the Washington co·al. 

This is the only known appearance in Ohio of a 

brackish-water form above the mid-Conemaugh 

Skelley Hm·estone. 

PLANTS (INCLUDING PERMIAN) 

Plant impressions and compressions are abundant 

throughout the osection, particularly in the shales 

overlying coals. The flora of the Pennsylvanian in 

the Appalachian basin was divided into several zones 

by Read (1947). The flora of Read's Mariopteris 

pygmaea zone (fig. 8) is found in the roof shale of 

the Sharon coal (Pottsville Group) in northeastern 

Ohio. Cas.ts and molds of Lepidodendron, Stigmaria, 

and Calamites are common in sandstone, particularly 

that directly overlying coal. Petrifactions are less 

common, although some notable examples have been 

found. The Middle Branch of the Shade River in 

Lodi Township, Athens County, has long been 

famous for well-preserved (petrified) Psaronius. 

Hildreth ( 1838, p. 43) first described this general 

locality, and Andrews ( 1873, p. 287-288) placed 

the stratigraphic position in the lower part of the 

Monongahela (above the Pomeroy coal of Andrews) ; 

Andrews also used the term PsaronittS in his text. 

Blickle (1940) and Morgan (1959) described 

PsaronittS of the Shade River area in detail from 

the extensive collection of Blickle. Coal halls containing poorly preserved material have been known 

from Ohio for several years (Denton and others, 

1961, p. 154) ; however, only recently did Rothwell 

( 1976) and Good and Taylor ( 197 4) des.cribe wellpreserved coal-ball floras from the middle Conemaugh and Monongahela Groups, respectively. 

The first flora repo-rted from Ohio and one of the 

earliest, if not the earliest, paleo-botanical account in 

the United States was published in' 1821 by Ebenezer Granger on plant impressions found in the 

uppermost part of the Pottsville Group at Zanesville, Muskingum Countx, Ohio. The material, which 

included N europteris grangeri Brongniart, was collected by Granger probably just below the Brookville coal at the Putnam Hill section on the west 

bank of the Muskingum River. 

Another locality with a rich and interesting flora 

was described by Andrews (1875) from the lower 

part (7-9 m or 25-30 ft above the Maxville Limestone) of the Pottsville Group; the specimens were 

collected about 2 miles east o.f Rushville, Perry 

County, Ohio. Specim·ens identified and illustrated by 

Andrews included s·everal species of Megalopteris 

and Orthogoniopteris. These lo-calities, and many 

others, are listed and discussed by Stout ( 1945) . 

Many other papers on Carboniferous floras are listed 

by Romans and McGann ( 197 4) . 

ECONOMIC PRODUCTS 

Carbo-niferous rocks in Ohio have been and continue to be a major source of valuable mineral 

resources. The Pennsylvanian is most noted for 

coal, but clay, sandstone, shale, and oil and gas 

(mostly in the past) have also made important contributions to the State's mineral wealth. Sandstone, 

oil and gas (mostly in the past), and shale have 

been the m·aj or resources produced from Mississippian rocks. 

COAL 

Coal is clearly the leading economic product of 

the Pennsylvanian System in Ohio and, in fact, is 

the most valuable mineral resource produced in the 

State. Coal beds assignable to the Monongahela 

Group (Upper Productive of early classifications) 

are the State's current m:ajor producing seams. Coals 

of the Allegheny Group (Lower Productive of early 

classifications) presently are second in total production. Coals of the Pottsville Group· were formerly 
E22 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

produced in Ohio, whereas mining of coal of the 

Conemaugh (Lower Barren of early classifications) 

has been of very minor importance. The Mississippian System in Ohio is not coal bearing. 

From 1800, the first year of recorded production, 

to 1974, more than 2.7 billion tons of coal were 

mined in Ohio. The highest tonnage recorded for a 

single year was 55.1 million tons in 1970. The 

second highest year was 1918, when more than 

47.9 million tons were mined. The character of the 

State's coal mining industry changed dramatically 

from 1918, ~hen less than 2 million tons of coal 

was produced by open-pit m•ethods, to 1970, when 

a:bout 37 million tons of the record total was from 

open pits. Strip mining began in Ohio in 1914, but 

did not .become important until Wor.ld War II. From 

1960 to 1970, strip mining increased and in 1970 

accounted for more than 70 percent of the State's 

total p·roduction. In recent years, however, the percentage of the State's coal production from underground mining has been increasing slowly (Collins, 

1976). 

At the pres·ent time, the most productive seams 

are, in des·cending order of importanc·e, Pittsburgh 

(No. 8), Meigs Creek (No. 9), Middle Kittanning 

(No. 6), Lo·wer Freeport (No. 7A), and Waynesburg (No. 11). The Upper Freeport (No. 7), Lower 

Kittanning (No. 5), Quakertown (No. 2), and 

Sharon (No. 1) coals were formerly more extensively mined, but depletion of reserves, changes in 

mining methods, and economics have greatly reduced the importance of these seams. 

Ohio's coals all fall into the high-volatile, bituminous rank and range from 5 to 20 percent ash, 

from 1 to 6 .percent sulfur, and from 10,000 to 13,000 

Btu. Low-sulfur ·coals, principally the Sharon and 

Quakertown, were formerly mined in Ohio, but 

most of the known reserves of these coals have been 

depleted. Most of the State's remaining resources 

fall into the medium (l.l to 3.0 percent) to high 

(more than 3 percent) sulfur range. 

On the basis of the latest resource tabulation of 

46,488,251,000 tons (Brant and DeLong, 1960), less 

5,395,442,000 tons mined and lost to mining and 

less 50 percent postulated to unavailability, 20, 

546,404,500 tons are left as Ohio's resource base. 

The resource base, however, includes coal not minable under current economic and technological conditions and, therefore, does not define the amount 

of coal that is presently available for production. 

CLAY AND SHALE 

Clay was formerly produced in· considerably 

greater quantities than it is at present. Competition 

from concrete and plastics and from foreign pottery 

has made .major inroads on Ohio's potte·ry and 

structural clay products industry. However, Ohio 

has traditionally led the Nation in the production 

of fireclays (coal underclays) and the production of 

structural clay products (such as sewer pipe, drain 

tile, and brick). Ohio is also a major p·roducer of 

refractories. 

Buff-burning clays particularly suitable for face 

bdck are confined entirely to the Pennsylvanian 

System and primarily to the Pottsville and Allegheny Groups. The Allegheny Hroup is the principal 

clay-producing sequence of the State, primarily because of the Lower Kittanning clay. The Lo·wer 

Kittanning, which immediately underlies the Lower 

Kittanning ·coal, is both .the State's most widespread 

and most productive clay unit. This unit has been 

worked extensively for day us·ed in the manufacture 

of such products as refractories, s·ewer tile, building 

brick, wall and floor tile, and pottery ; Lower Kittanning clay also has been us.ed in cement for lightweight aggregate .and as foundry bonding clay. 

The Clarion, Oak Hill, Middle Kittanning, Lower 

Freeport, and Upper Freeport are other important 

clay units of the Allegheny Group. At the present 

time only the Clarion is being widely produced. 

The clay resources of the Pottsville Group are 

the second most important in the State in production. The Tionesta and Brookville ·clays ·are worked 

rather extensively for use in the manufacture of 

face brick, .sewer tile, wall tile, and refractories and 

are next in importance to the Lo.wer Kittanning. 

The clays of the Conemaugh and Monongahela 

Groups tend to be thin and dis·continuous and are 

for the most part unsuited for ·ceramic use; these 

clays have been o.f little importance to the State's 

ceramic industry. 

The Mississippian-age Bedford Shale and Logan 

Formation are worked in several localities in the 

State for clay used in the manufacture of face 

brick and tile. Pennsylvanian-age shale is sometimes 

blended with the clay to lower the firing range of 

the product. 

SANDSTONE 

Ohio is the largest producer of sandstone in the 

United States. Sandstone was. one of the first 

mineral resources of the Carboniferous to be exploited by the early European settlers in Ohio 

(Stout, 1944). Sandstones useful for building stone, 
OHIO E23 

flagging, ·curb stone, decorative stone, refractories, 

grindstone, and pulpstone are abundant throughout 

the Carboniferous. In a few localities, upper Mississippian and lower Pennsylvanian sandstones are 

suitable sources of glass sands and silica pebb~e. 

The use of sandstone as building stone has decreased substantially ·since the early 1900's owing to 

the use of cement block and brick. Grindstones have 

similarly lost favor to artificial abrasives. Even 

though many classical uses of ·sandstone have 

diminished over :the years, other uses have been 

found, and production still remains relatively high. 

Present uses include dimension stone, aggregate, 

glass sand, metallurgical pebble, refractory linings, 

foundry •sand, and riprap. 

The principal sandstone units that have been developed ,in the Mississippian include units in the 

Bedford and Berea and units o.f the Cuyahoga, 

notably the Buena Vista and the Black Hand. 

Presently the Berea Sandstone in Lorain, Erie, and 

Huron Counties to the north and the Buena Vista 

mem.ber of the Cuyahoga Formation in Scioto 

County to the south are the principal producing 

units. 

The Pennsylvanian System in Ohio contains many 

beds of sandstone about 6 to 12 m (20 to 40 ft) in 

thickness ·and several that locally thicken to as much 

as 31+ m (100+ ft). Many of these units have 

been ~exploited locally on a small scale. Two units, 

the Sharon conglomerate and Massillon sandstone, 

have been rather widely developed commercially and 

are the principal producing units at the present 

tim·e. 

OIL AND GAS 

Carboniferous rocks have played a significant role 

in the development o.f the oil and gas industry in 

Ohio. Oil w·as known to exist in Ohio from the 

earliest days o.f statehood. A brine well drilled in 

1814 in Noble County yielded large quantities of 

oil and gas (Hildreth, 1833, p. 64). Commercial 

development, however, did not start until 1859-60, 

when a gas well was developed in the Berea Sandstone at East Liverpool, Columbiana County. The 

success of the Drake well in western Pennsylvania 

in 1859 sparked drilling activity in several areas 

of eastern Ohio. Carboniferous rocks were the object 

of interest in these early exploration programs. 

Oil was discovered in 1860 at Macksburg, Washington County, in stratigraphic units assignable to 

the Pennsylvanian-age Conemaugh Group and in 

Mecca Township, Trumbull County, in the Mississippian-age Berea Sandstone. By the late 1800's, oil 

and gas had been discovered also in the Missi.ssippian-age Cuyahoga and Logan Formations and in 

the Pennsylvanian-age Pottsville and Allegheny 

Groups. 

With the exception of the Berea Sandstone, extensive development of Carboniferous rocks in Ohio 

for oil and gas seems to be unlikely. The Berea, because of its much greater persistence and, in some 

areas, more uniform thickness, still offers opportunity for development. 

LIMESTONE 

The Maxville Limestone, as stated earlier, is the 

orily carbonate unit in the Mississippian System of 

Ohio, and is the single most .important limestone in 

the Carboniferous. The Maxville ha:s been used for 

the manufacture of agricultural lime, quicklime, 

cement, road metal, railroad ballast, blast-furnace 

flux, and dimension stone. Presently, the unit is 

worked underground in Muskingum County for the 

manufacture of cement. Stone for riprap, road 

metal, concrete aggregate, and agricultural lime is 

quarried in the same area, as well as in Perry 

County. The Maxville formerly was deep-mined in 

Upper Township, Lawrence County, for cement 

stone. 

Several Pennsylvanian-age marine limestones are 

commercially quarried: the Putnam Hill and Vanport limestones in the Allegheny Group and the 

Brush Creek and Cambridge limestones in the Conemaugh Group. The Vanport is the most extensively 

worked of these units. The bed is presently quarried 

for cement stone in Lawrence and Mahoning Counties and for riprap, road m·etal, and cement aggregate in Jackson, Lawrence, Mahoning, and Tuscarawas Counties. The unit is quarried for fluxstone 

in Mahoning County. 

The Putnam Hill is worked for cement stone as I 

well as for crushed stone in Stark County. The 

Brush Creek limestone is quarried for crushed stone 

in Athens County, and the Cambridge limestone is 

quarried for the same purpose in Guernsey County. 

Freshwater limestones of the Conemaugh and 

Monongahela Groups are worked in a very small 

way for agricultural lime and for road metal. The 

Ewing limestone (Conemaugh Group) in Noble 

County, the Fishpot limestone (Monongahela 

Group) in Belmont and Harrison Counties, and the 

Benwood lim·estone (Monongahela Group) in Morgan and Washington Counties are the units presently being worked. 

Other Pennsylvanian units have been worked on 

a minor scale. The thinness of the marine beds and 
E24 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

the poor quality of the freshwater units are limiting 

factors in the use and development of these resources. 

GROUND WATER 

Ground water is not produced in prolific amounts 

from the Carboniferous rocks of Ohio, and major 

supplies must be obtained from surface waters. 

Units in the Pennsylvanian System throughout the 

State, with some notable exceptions, produce water 

at a general rate o.f 0.3 liters per second (5 gallons 

per minnte) O·r les·s. Major exceptions are the 

Sharon and Massillon sandstones (Pottsville 

Group), which normally produce 2 to 6 liters per 

second (25 to 100 galloris per minute). Rare local 

exceptions do occur, and production o.f several hundred gallons per minute has been reported from 

Pennsylvanian units .. Low ground-water yield is related to the fact that the Pennsylvanian section i·s 

to a large extent composed of impermeable shale 

and mudstone and sandstone which tend to have 

relatively low permeabilities. I 

M.ississ.ippian "Sandstone is generally somewhat 

cleaner, better sorted, and more permeable. Mississippian sands also tend to be somewhat more 

regular in distribution. Most of the region where 

water may be obtained from these s~ands will yield 

0.3 to 2 liters per second (5 to 25 gallons per 

minute). As in the overlying Pennsylvanian, a unit 

rarely delivers several hundred gallons per minute. 

REFERENCES CITED 

Andrews, E. B., 1871, Report of progress in the second dis~ 

trict: Ohio Geol. Survey Rept. Prog. 1869, pt. 2, p. 

55-142. 

---1873, Report on second geological district: Gallia, 

Meigs, Athens, Morgan, Muskingum Counties: Ohio 

Geol. Survey Rept. 1, pt. 1, Geology, p. 225-364. 

---1875, Descriptions of fossil plants from the coal meas~ 

ures of Ohio: Ohio Geol. Survey Rept. 2, pt. 2, Paleon~ 

tology, p. 413-426. 

Arkle, Thomas, Jr., 1959, Monongahela series, Pennsylvanian 

System, and Washington and Greene Series, Permian 

System, of the Appalachian basin, Field Trip 3 of Geol. 

Soc. America, Guidebook for field trips, Pittsburgh Mtg., 

1959, p. 115-141. 

Baird, Donald, 1964, The aistopod amphibians surveyed: 

Breviora, no. 206, 17 p. 

Berman, D. S., and Berman, S. L., 1975, Broiliellus hektotopos 

sp. nov. (Temnospondyli: Amphibia) Washington For~ 

mation, Dunkard Group, Ohio, in Barlow, J. A., ed., The 

age of the Dunkard-Proceedings of the First I. G 

White Memorial Symposium, Morgantown, W.Va., 1972: 

Morgantown, West Virginia Geol. and Econ. Survey, p. 

69-78. 

Berryhill, H. L., Jr., and Swanson, V. E., 1962, Revised 

stratigraphic nomenclature for Upper Pennsylvanian 

and Lower Permian rocks, Washington County, Pennsylvania: U.S. Geol. Survey Prof. Paper 450-C. p. C43-C46. 

BHckle, A. H., 1940, Ohio Psaronii: Univ. Cincinnati, unpub. 

Ph.D. dissert., 62 p. 

Brant, R. A., and DeLong, R. M., 1960, Coal resources of 

Ohio: Ohio Div. Geol. Survey Bull. 58, 245 p. 

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OHIO E25 

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E26 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

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18, p, 159-168. 
Th.e Mississippian and Pennsylvanian 

(Carboniferous) Systems in the United States-.-

Keritucky 

By CHARLES L. RICE, EDWARD G. SABLE, GARLAND R. 

DEVER, JR., and THOMAS M. KERN 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1110-F 

Prepared in cooperation with the 

/(entucky Geological Survey 

Historical review and summary of areal, stratigraphic, 

structural, and economic geology of Mississippian 

and Pennsylvanian rocks in Kentucky 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1979 

CONTENTS 

Page 

~bstract ----------------------------------------------------------------- F1 

Introduction -----------.-------------------------------------------------- 2 

Physiography -------------------------------------------------------- 2 

Scenic features ------------------------------------------------------- 3 

General history of the Carboniferous ---------------------------------- 4 

Mississippian System. ----------------------------------------------------- 5 

Geologic setting --------------------------------------------~--------- 5 

Stratigraphy --------------------------------------------------------- 5 

Biostratigraphy ------------------------------------------------------ 10 

Mississippian-Pennsylvanian boundary ------------------------------------- 11 

Pennsylvanian strata of eastern Kentucky ---------------------------------- 14 

Geologic setting ------------------------------------------------------ 14 

Stratigraphy --------------------------------------------------------- 14 

Pennington Formation -------------------------------------:-------- 16 

Lee Formation --------------------------------------------------- 16 

Breathitt Formation ---------------------------------------------- 17 

Conemaugh and Monongahela Formations -------------------------- 20 

Pennsylvanian strata of western Kentucky --------------------------------- 20 

Geologic setting ------------------------------------------------------ 20 

Stratigraphy --------------------------------------------------------- 21 

Biostratigraphy of the Pennsylvanian of Kentucky -------------------------- 22 

Post-Carboniferous tectonic events ----------------------------------------- 23 

Economic geology __________________________ --------------- ____ ----------- 24 

References cited ---------------------------------------------------------- 28 

ILLUSTRATIONS 

Page 

FIGURE 1. Geologic map of Kentucky showing distribution of Carboniferous rocks --------------------------- F2 

2. Physiographic map of Kentucky ----------------------------------------------------------------- 3 

3. Cross section showing Mississippian rock units and relationships in Kentucky ---------------------- 6 

4. Chart showing stratigraphic nomenclature of the Mississippian System in Kentucky and southeastern 

Illinois ------------------------------------------------------------------------------------ 7 

5. Chart showng stratigraphic nomenclature of tbe Chester Series and equivalent strata in Kentucky ___ 8 

6. Chart showing occurrences of selected Mississippian fossil fauna helpful in recognition of map units in 

Kentucky ---------------------------------------------------------------------------------- 12 

7. Sketch map of sub-Pennsylvanian valley systems in the western Kentucky coal field ----------------- 13 

8. Generalized geologic map of the pre-Pennsylvanian surface in the northwest part of the Cumberland 

Plateau, eastern Kentucky --------------------------------------------~--------------------- 13 

9. Generalized cross sections showing two interpretations of Carboniferous rocks exposed along Interstate Highway 64, eastern Rowan and western Carter Counties ------------------------------ 13 

10. G(\!neralized cross sections of the Pennsylvanian System of eastern and western Kentucky ---------- 15 

11. Isopach map of the interval between the base of the Kendrick Shale of Jillson (1919) and the base of 

the Magoffin Member of the Breathitt Formation in eastern Kentucky ----------.,.--------------- 16 

12. Correlatiion chart of the Lee Formation in southeastern Kentucky and southwestern Virginia ---------- 17 

13. Correlation chart of the Pennsylvanian System of eastern Kentucky showing coal beds and other key 

beds -------------------------------------------------------------------------------------- 18 

14. Diagram comparing nomenclature of Owen (1856, 1857a,b) with that of this report ---------------- 21 

15. Generalized structure map of Kentucky -------------·-------------------------------------------- 24 

16. Graphs showing coal production of the eastern and western coal fields of Kentucky from 1890 to 1975 

showing surface and underground mining ---------------------------------------------------- 25 

17. Chart showing sources of oil, natural gas, and industrial and metallic minerals in Carboniferous rocks 

of western Kentucky __________________________ . _____ .,_ ____ ------ ____ __ ____ __ ___ _ __ ___ ___ _ ___ 26 

18. Chart showing sources of oil, natural gas, and industrial metallic minerals in Carboniferous rocks of 

eastern Kentucky -----------------------------·-------------------------------------------- 27 

In. 
THE MISSISSIPPIAN AND PENNSYLVANIAN (CARBONIFEROUS) 

SYSTEMS IN THE UNITED STATES-KENTUCKY 

By CHARLES L. RICE/ EDWARD G. SABLE·, 

GARLAND R. DEVER, JR., and THOMAS M. KEHN 1 

ABSTRACT 

Kentucky is unique among the States of the Eastern United 

States in that it contains parts of two major sedimentary 

basins that have nearly complete successions of Carboniferous 

rocks. These basins, the Appalachian and Easte·rn Interior 

each contain more than 2,100 m of Mississippian and Penn~ sylvanian strata. · 

Carboniferous strata directly underlie four of Kentucky's 

six principal physiographic regions: the Knobs, Mississippian 

Plateau, Western Coal Field, and Cumberland Plateau. 

Weathering and erosion of Carboniferous rocks in these 

regions have produced a variety of scenic ·features such as 

caverns, gorges, natural bridges, and waterfalls. 

Mississippian rocks conformably overlie Late Devonian 

strata and are principally of marine origin. Environments of 

deposition ranged from relatively deepwater basin to lower 

delta plain. The Mississippian succession in the State consists of four major lithogenetic groups: ( 1) distal terrigenous detrital deposits of westward and southward prograding 

deltaic systems (Kinderhook, Osage); (2) marine carronate 

deposits, partly basinal, but dominantly shelf limestone and 

dolo~ite (Osage, Meramec); (3) rhythmically alternating 

marme carbonate and terrigenous detrital deposits shelf 

limestone alternating with sandstone and shale from ;, southward and southwestward prograding delta (Chester); and 

( 4) terrigenous detrital deposits of westward- and southwardprograding deltaic systems (Chester) . Major source areas 

for terrigenous sediments were to the northeast and east of 

Kentucky. Penecontemporaneous tectonic activity is suggested 

by distinct variations in the thickness and distribution orf 

units along the trends of major structural features in parts 

of the State. Some biostratigraphic zones virtually correspond 

with lithostratigraphic units and serve as practical aids in 

field identification. 

The . Mississippian-Pennsylvanian systemic boundary generally IS marked by an erosional unconformity, which locally 

may represent a removal of more than 275m of M;ssissippian 

strata in western Kentucky and more than 60 m in eastern 

Kentucky. In southeastern Kentucky, depqsition was continuous from Late Mississippian into Early Pennsylvanian time. 

A ~ecently proposed thesis that the Mississippian-Pennsylv~nian unco~formity in ~ortheastern Kentucky is a depositional or facies boundary IS untenable in view of field relation1 Kentucky Geological Survey, Lexington, Ky. 40606. 

ships between lithologic· units in the area. The sub-Pennsylvanian surface across east-c·entral and northeastern Kentucky 

also shows a truncation of progressively older Mississippian 

strata toward the north. 

The Pennsylvanian strata of eastern Kentucky form a 

clastic wedge that thickens southeastward toward the axis of 

the Appalachian basin. The rocks are largely deltaic in origin, 

dominantly thick orthoquartzite in the lower part and siltstone, shale, and relatively thin discontinuous subgraywacke 

in the upper part. Channel-fill deposits of pebbly orthoquartzite of the Lee Formation (Morrow) form a series of broad 

lobes generally oriented northeast-southwest, parallel with 

the axis of · the Appalachian basin and with a dominant 

southwest transport direction. The Breathitt Formation ( Morrow, Atoka, Des Moines) consists of siltstone, clay shale, subgraywacke, coal, ironstone, and limestone. It was deposited 

largely in lower and upper. delta-plain environments: tidal 

flats, interdistributary bays, swamps, and shallow anastomosing stream channels. As many as 30 major coal beds or coal 

zones are present in the formation. Stratigraphic subdivision 

of the Breathitt is based on recognition of key beds, particularly marine units, and sequences of key beds. The Conemaugh and Monongahela Formations (Missouri, Virgil) are 

present in northeastern Kentucky. In contrast with the darkcolored shale of the Breathitt, the Conemaugh and Monongahela are characterized by the presence of red, green, and 

variegated shale. The formations apparently represent deltaic 

deposits that were repeatedly inundated by eastward-transgressing seas. 

The Pennsylvanian strata of western Kentucky in the 

southern part of the Eastern Interior basin also are largely 

deltaic in origin. T.heir lithology is similar to that of the Lee 

and Breathitt Formations of eastern Kentucky except that 

marine limestones, repl.'esenting as many as 35 transgressions, 

form a larger part of the succession. About 24 principal coal 

beds or coal zones have been identified in western Kentucky. 

Limestones are important key beds for stratigraphic subdivision, but the most useful marker bed is the No. 11 coal bed 

which has a distinctive clay shale parting. Subsidence was 

relatively uniform across the basin during Early and Middle 

Pennsylvanian time; the alternation of shallow marine and 

deltaic deposits probably is related to the shifting of southward and southwestward prograding delta lobes. 

Carboniferous rocks are the major source of mineral resources in Kentucky. The State currently is the leading producer of bituminous coal in the United States and has an 

estimated original reserve of about 65.6X 10° metric tons of 

Fl 
F2 THE MISSISSIPPIAN f'\ND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

high-voltatile A and B bituminous coal in the Pennsylvanian 

deposits of eastern and western Kentucky. A large percentage 

of the oil, natural gas, and industrial and metalic minerals 

produced in the State has come from Carboniferous rocks. 

INTRODUCTION 

Carboniferous strata underlie and crop· out in 

about two-thirds of the surface area of Kentucky 

(fig. 1). The State is unique in the Eastern United 

States because it contains. parts of two major sedimentary basins that have nearly complete successions of Carboniferous rocks. These basins, the Appalachian and the Eastern Interior, though different 

in their tectonic and depositional histories, each 

contain more than 2,100 m of Carboniferous strata 

in Kentucky representing both the Mississippian 

and Pennsylvanian System~s. The basins are linked 

by a belt of lower Carboniferous rocks. (Mississippian Osage and Mera.mec ages) extending across 

the Cincinnati arch in south-central Kentucky. Mississippian rocks (mainly limestone, sandstone, shale, 

and siltstone) are dominantly marine in origin, and 

Pennsylvanian rocks (mainly sandstone, siltstone, 

shale, and coal) are dominantly of deltaic and fluvial 

origin. 

Carboniferous rocks are the major source of mineral resources in Kentucky. The State currently. is 

the leading producer of bituminous coal in the 

United States, producing from Pennsylvanian deposits in both the App·alachian and Eastern Interior 

EXPLANATION 

~ Cretaceous rocks underlain by Mississippian rocks 

~ Cretaceous rocks underlain by pre-Mississippian rocks 

[=:J Pennsylvanian rocks 

.. Mississippian rocks 

[=:J Pre-Mississippian rocks 

basins-the eastern and western Kentucky coal 

fields, respectively. Carboniferous units are also a 

principal source of petroleum, natural gas, limestone, sandstone, shale, clay, fluorspar, sphalerite, 

galena, barite, and, formerly, iron ore. 

The stratigraphic nomenclature used in this paper 

has not been reviewed by the Geologic Names Committee of the U.S. Geological Survey. The nomenclature used here conforms with current usage of the 

Kentucky Geological Survey. 

PHYSIOGRAPHY 

Carboniferous strata directly underlie four of 

Kentucky's six principal physiographic regions.: the 

Knobs, Mississippian Plateau, Western Coal Field, 

and Cumberland Plateau (fig. 2). The other regions 

in the State are the Blue Grass, underlain by Ordovician, Sdludan, and Devonian rocks, and the Mississippi Embayment where Cretaceous and Tertiary 

sedimentary deposits rest on Paleozoic rocks. 

The Knobs region is a narrow, arcuate belt of 

conical hills, or knohs, around the outer border o.f 

the Blue Grass region. The Knobs are erosional 

remnants, consisting of Mississippian (Osage) shale 

and ·siltstone, wh~ch occur along the front of the 

Pottsville escarpment across east-central Kentucky 

and along the front of Muldraughs Hill across westcentral and south-central Kentucky. Muldraughs 

Hill is a limestone-capped escarpment bordering the 

50 100 MILES 

50 100 KILOMETERS 

FIGURE 1.-Geologic map of Kentucky showing distribution of Carboniferous rocks. 
KENTUCKY F3 

SCENIC AREAS 

1. Breaks of the Sandy 

2. Red River Gorge 

3. Rockcastle River Gorge 

4. Cumberland River Gorge 

5. Mammoth Cave 

I " 100 KILOMETERS 

FIGURE 2.-Physiographic diagram of Kentucky (From Lobeck, 1929), showing the location of scenic areas. 

M.ississipp.ian Plateau region ; the Pottsville escarpment, capped by Lower Pennsylvanian sandstone, 

borders the Cumberland Plateau. 

The Mjssissippian Plateau forms a broad, arcuate 

belt around the Western Coal Field and extends 

eastward to the Pottsville escarpment. It consists of 

two principal parts divided by the Dripp.ing Springs 

escarpment, an east- and south-facing ridge generally .capped ·by the Big CHfty ·sandstone Member 

of the ·Golconda Formation (Chester). The outer 

part is a broad plain w.ith extensive karst development underlain mostly by the St. Louis and Ste. 

Genevieve Limestones ( Meramec) . The inner part of 

the plateau is a dissected upland of moderate relief 

underlain by limestone, sandstone, and ·shale of 

Chester age. 

The Western Coal Field is a gently rolling to hilly 

upland dissected by stre·ams occupying broad, very 

flat, .poorly drained and often swampy valleys. Two 

major rivers drain the area; one has its headwaters 

in the coal field. The area is underlain by Pennsylvandan (Morrow-v.irg.il) shale, sandstone, limestone, 

and coal. Deep weathering has made natural exposures sparse except along the margins of the basdn 

where streams have cut into the older and generally 

more resistant Lower Pennsylvanian rocks. Sandstone of the Caseyville Formation (Morrow) forms 

prominent ridges and cliffs along parts of the border 

of the coal field, and thes·e constitute the Pottsville 

escarpment of that area. 

The Cumberland Plateau, which is underlain by 

Pennsylvanian (Morrow-V1irgil) shale, .sandstone, 

and coal, is an intricately dissected upland of concordant sharp ridges and V-shaped valleys. It is 

bordered on the west ·by the Pottsville escarpment. 

Lower PeJ}.nsylvani'an (Morrow) .sandstone, overlain 

by less resistant shale, locally forms broad uplands 

of little rel.ief along the south-central and southwest 

border of the plateau. Pine and Cumberland Mountains, two northeast-trending ridges also ·capped by 

Lower Pennsylvanian (Morrow) sandstone, border 

the plateau on the southeast. Four r.ivers drain the 

area, three of which have their headwaters generally in or near Pine and Cumberland Mountains 

where local relief is as much as 700 m. 

SCENIC FEATURES 

Weathering and erosion of Carboniferous rocks in 

Kentucky ·have produced a variety of scenic features 

of interest to both laymen and geologists (McFarlan, 

1958). Many of these features are available to the 

general public and ·have been incorporated into 

State and National parks (fig. 2). Some of the most 

spectacular scenery in the State is found in the 

Breaks of the Sandy, a gorge cut through the north 

end of Pine Mountain by the Russell Fork of the 

Big Sandy River (McGrain, 1975), and in the gorges 

of the Red, Roc·kcastle, and Cumberland Rivers and 

South Fork of the Cumberland River along the western border of the Cumberland Plateau. Many nat-
F4 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

ural bridges. have formed in narrow, sandstonecapped divides, particularly in the Red River area 

(McFarlan, 1954), and many waterfalls, including 

the 20-m Cumberland Falls (McGrain, 1955), have 

formed on resistant Pennsylvanian sandstone. 

The Mississippian Plateau of western Kentucky is 

a classic karst region, containing a broad sinkhole 

plain and extensive systems of underground drainage and caverns, including the Mammoth Cave-Flint 

Ridge cave system, formed in the St. Louis and Ste. 

Genevieve Limestones, and Girkin Formation (Mississippian) (Liversay, 1953). In eastern Kentucky, 

caves that have formed locally in the Mississippian 

limestone northwest of the Pottsville escarpm·e~t include the Carter and Cascade Caves in the northern 

part of the area (McGrain, 1954) and those in the 

Sloans Valley system near the south border of the 

State (Malott and McGrain, 1977). 

The conical hills of the Knobs, remnants of the 

uplands behind the retreating Muldraughs Hill and 

Pottsville escarpment, form a stliiking example of an 

erosional landscape (McGrain, 1967). 

Many exposures of Carboniferous rocks ·can be 

found in roadcuts along major Federal and State 

highways, dn strip mines .of the eastern and western 

coal fields, and in limestone quarries. (See, for example, Dever and M·cGra:in, 1969; Smith and others, 

1969, 1971; Stokley and McFarlan, 1952). Extensive exposures of complex Pennsylvanian deltaic 

sequences of shale, sandstone, and coal are found in 

roadcuts as much as 100 m high in eastern Kentucky, particularly along U.S. Highway 23 in the 

v~icinity of Pikeville. 

GENERAL HISTORY OF THE CARBONI·FEROUS 

The Carboniferous periods in Kentucky have generally been treated as three separate top.ics : the Mississippian and the Pennsylvanian of eastern Kentucky and the Pennsylvanian of western Kentucky. 

Miller (1919, p. 94-141), in the first ·CO·mprehensive synthesis of the geology of Kentucky, cited 

early work on Mississippian rocks by D. D. Owen, 

A. F. Foerste, E. 0. Ulrich, Charles Butts, Stuart 

Weller, and others. These .pioneer efforts were followed by systematic studies of Mississippian rocks 

in Kentucky :and adjacent States by Butts (1917, 

1922), Ulrich (1917), Stockdale (19-39), Bind by 

several State surveys· dn a cooperative plan for 

geologic mapping along the borders of the Eastern 

Interior basin (Weller and Sutton, 1940) . McFarlan 

(1943, p. 57-95), incorporated resuUs o.f these later 

studies in an expanded revision of Miller's earlier I 

synthesis. Definitions and oo.rrelations of Upper 

Mississippian rock units Jn western Kentucky were 

refined by S.touder (1941) and McFarlan and others 

( 1955), and in eastern Kentucky by McFarlan and 

Walker ( 19.56) . 

The first usable subdivision of the Pennsylvanian 

strata of eastern Kentucky was made by Campbell. 

He named the Lee Formation in the Cumberland 

Mountains ( 1893) and later described the formation .in exposures near the Pottsv:ille es,ca.rpment 

( 1898), giving the name Breathitt Formation to the 

overlying Pennsylvanian rocks. In northeastern 

Kentucky, Phalen ( 1912) divided the Pennsylvanian 

rocks into the Pottsville, Allegheny, Conemaugh, and 

Monongahela Formations. Ashley and Glenn (1906) 

subdivided the thick sequence of Breathitt rocks of 

the Cumberland overthrust block and named the 

Hance, Mingo, Catron, H~ignite, and Bryson Formations, ~selec,ting ~certain coal beds as formational 

boundaries. 

Extensive stratigraphic analyses and syntheses of 

the Pennsylvanian rocks of eastern Kentucky have 

been made by Wanless (1939, 1946, and 1975a) as a 

part of his studies of the Appalachian basin. Huddle and others ( 1963), aided by many earlier reports of the Kentucky Geological Survey and the 

U.S. Geological Survey, made detailed stratigraphic 

analys·es o.f each coal district in eastern Kentucky 

and computed its coal reserves. 

The earliest geologi.cal work in the western Kentucky coal field was carried out by Owen from early 

1854 to 1859. He named the Caseyville Formation 

and the principal limestone beds of the overlying 

"Coal Measures," and est~blished the system of 

numbering coal beds that has been only slightly modified hy subsequent work. Significant stratigraphic 

contributions were made by Glenn (1912a and b, 

and 1922), who named the Tradewater, Lisman,_ and 

Dixon Formations, and extended the Carbondale 

Formation from Illinois into Kentucky. Kehn 

(1973) comhined the Lisman and Henshaw Formations to form the Sturgis Formation. Other impo·rtant contributions include reports by Hutchinson 

(1912) and Lee (1916), who were first to map and 

describe in detail the stratigraphy of the Pennsylvanian of western Kentucky, and Smith and Smith 

(1967), who were first to describe in detail the 

uppe·r part of the Pennsylvanian section. Wanless 

( 1975b) summarjzed ·the stratigraphy o.f the Western Coal Field as a part of his investigation of the 

Pennsylvanian of the Eastern Interior basin (Illinois basin) . 

In 1960, the U.S. Geological Survey and the Kentucky Geolog;ical Survey be·gan a cooperative geologi-
KENTUCKY F5 

cal mapping program, and by 1977, all Kentucky had 

been map~ped geological.ly at a scale of 1 :24,000; 

these maps are published in the GQ (Geologic Quadrangle) Map Series of the U.S. Geological Survey. 

During this period, many refine.ments were made in 

Carboniferous Mthostratigraphy (Englund and Windolph, 1971; Kepferle, 1971; Kepf.erle and Lewis, 

197 4; Lewis, 1971; Outerbridge, 1976; Sable and 

others, 1966; Weir and others, 1966) ; resource investigations by the Kentucky Geological Survey involving oil and gas, coal, limestone, and day were 

accelerated, along with associated stratigraphic 

studies, and have resulted in many publications by 

the State Survey. Investigators using the geologic 

maps have published other research reports on details of the stratigraphy and sedimentation of the 

Missis·sipp!ian (Kepferle, 1977; Weir, 1970; Indiana 

University, 1969, 1972; Vincent, 1975) and of the 

Pennsylvanian (Englund, 1964; Kehn, 1973; Kosanke, 1973). The most recent ·summary o.f Carboniferous rocks of the Eastern Interior basin (Pryor 

and Sable, 197 4) ·covers parts of Kentucky and cites 

principal modern references. Stratigraphic information collected during the cooperative mapping program was used in compiling the present report. 

MISSISSIPPIAN SYSTEM 

Mississippian rocks in Kentucky are principally 

mar·ine; environments of deposition ranged from 

relatively deepwater basin through shallow subtidal 

and supratidal to lower delta plain. Dominant lithologies, relative thickness·es, and relationships of Mississippian units are shown in figure 3. Nomenclature 

and unit correlations ·currently used in Kentucky are 

basically lithostratigraphic (figs. 4 and 5). Some 

biostratigraphic zones virtually correspond with 

lithostratigraphic units and serve as practical aids 

in field identification and mapping (fig. 6). 

GEOLOGIC SETTING 

Basal Mis·sissippian rocks throughout Kentucky 

conformably overlie rocks of Late Devonian age, 

which are pr.incipally dark carbonaceous shale 

(Chattanooga, New Albany, and Ohio Shales) (fig. 

4). The top of the Chattanooga and New Albany is 

the top of the Devonian ·succession in western, southern, and west-central Kentucky. Carbonaceous shale 

of Mi·ssissippian age, .correlative with the Sunbury 

8hale, is present in ·uppermost New Albany beds of 

east-central Kentucky and the upper Chattanooga 

of southeastern Kentucky. In the parts of northeastern and southeastern Kentucky where the Bedford .Shale 'and Berea Sandstone are present between 

the Ohio ('or Chattanooga) and Sunbury Shales, the 

systemic boundary is within the Bedford S'hale. 

Mississippian strata in much of Kentucky are 

overlain by Pennsylvanian (Morro·w) rocks. The 

systemic boundary generally is a dis·conformity, but 

strata that show continuous deposition extending 

from Late Mississippian into Early Pennsylvanian 

time are locally preserved .in southeastern Kentucky. 

In extreme western Kentucky, Cretaceous sediments 

of the Mississippi Embayment unconformably ove,rlie Miss·,issippian units (fig. 1). 

The Appalachian and Eastern Interior basins 

presently are s·eparated by the north-tr·ending Cincinnati arch. (See fig. 15.) The exact nature of the 

arch during Carboniferous time ois uncertain. It was 

a pos.itive feature during Late Devonian time, but 

depositional patterns in the Borden Formation 

(Osage) .show no evidence o.f a north-trending arch 

across central Kentucky in Early Mississippian time. 

The Appalachian and Easte·rn Interior basins apparently were connected across southern Kentucky 

throughout Mississippian time, but the arch may 

have been a shoal or emergent lowland in northern 

Kentucky during the Late Mississippian. Tectonic 

activ;ity during the Carboniferous is .suggested by 

distinct thickness variations in Upper Mississippian 

units along the trends orf the Kentucky River fault 

system and Waverly arch in northeastern Kentucky 

(Dever and others, 1977) and, ·conjecturally, along 

the trend of the Rough Creek fault system in western Kentucky (Craig. and Connor, 1978) (s·ee fig. 

15). 

STRATIGRAPHY 

The Mississippian succession in Kentucky consists 

of four major lithogenetic groupings: 

1. Distal terrigenous detrital deposits (shale, siltstone, and sandstone) o.f westward and southward prograding deltaic systems (Kinderhook, 

Os-age): Bedford Shale, Berea Sandstone, Sunbury Shale, and Borden Formation below the 

Floyds Knob Bed. 

2. Marine carbonate deposits, partly basinal ·but 

dominantly shallow-water shelf limestone and 

dolomite (Osage, Meramec): Fort Payne Form-ation, Muldraugh and Renfro Members of 

Borden Formation;. Warsaw, Harrodsburg, 

Salem, St. Louis, and Ste. GeneV!ieve Limestones. 

3. Rhythmically alternating marine carbonate and 

terrigenous detrital deposits, shallow-water 

shelf limestone alternating with sandstone and 

shale from a southward and ·southwestward 
METERS 

PALESTINE!· ••. • .. 

wZ 

z!:2 

>I-

<< C1..::J!: 

t::~ 

Above terminology and boundaries are those of the Illinois Geological 

Survey 

WEST 

A 

..2 

~ 

~ 

~ C) 

c 

l 

50 100 150 KILOMETERS I I I I I ' I I I l 

0 25 50 75 MILES 

~ CQ 

EXPlANATION 

METERS 

30 

Q Sandstone ~ Argillaceous limestone 

[g) Siltstone 0±J Aranaceous limestone 

~A' 

0 

~~ ~cf 

I 

] 

~ -;, 

I 

- - - -\s;dfurdsh;ie -;nd 

Berea Sandstone 

D Shale IifiJ Oolitic, pelletal, or foraminiferal limestone 

~ Bituminous shale li!JiJ Bryozoan limestone 

EJ Calcareous shale ~ Crinoidallimestone 

e:I!J Limestone tt::±J Evaporite rock 

{£?iJ Dolomitic ~ Chert 

limestone IZ3J Dolomite GJ Glauconitic bed 

E!9 Siliceous carbonate 

FIGURE 3.--Cro.ss section showing Mississippian rock units and relationships in Kentucky. (All scales approximate.) 

EAST 

A" 

METER 

300 

200 

"'%j 

0') 

8 

~ 

tz:1 

a:: 

-

Ul 

Ul 

Ul 

Ul -

1-4 

1-0 

1-0 

-

> z 

> z 

t1 

1-0 

tz:1 

z 

z 

Ul 

~ 

tot 

< 

> z 

-> z 

Ul 

~ 

Ul 

8 

tz:1 

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Ul 

1-4 

z 

8 

~ 

tz:1 

d 

z 

-

8 

tz:1 

t1 

Ul 

8 

> 

8 

t_%j 

Ul 
KENTUCKY F7 

EASTERN INTERIOR BASIN APPALACHIAN BASIN 

~ (/) 

~ w ILLINOIS KENTUCKY a: 

w 

I I 

EAST-CENTRAL (/) 

SOUTHEASTERN WEST- SOUTH- SOUTHEASTERN (/) WESTERN AND CENTRAL CENTRAL NORTHEASTERN (PINE MOUNTAIN) 

PENNINGTON c=--?- PENNINGTON 

FORMATION ~~e~IE~s. > 

FORMATION 

? 

I z 

~ (CHESTERIAN UNITS ARE BANGOR a: 

~ SHOWN IN FIGURE 5) LIMESTONE UPPER 

MEMBER 

w UPPER ::c HARTSELLE u FORMATION MEMBER 

*KIDDER w ? 

LIMESTONE z 

0 w MEMBER 1-. 

*LEVIAS LIMESTONE *LEVIAS z (/) 

0 w w 

MEMBER OF LIMESTONE 1- ~ z 

~w (/) ::::J 0 

a: RENAULT LIMESTONI MEMBER w 1-

~ ROSICLARE ~ z (/) 

-z ::::J <( 

a.. AUX VASES >o ~ w 

::> WI- SANDSTONE w ~ 

SANDSTONE a1~ MEMBER 

STE. _, STE. GENEVIEVE ~ STE. GENEVIEVE ::::J (!) 

STE. (!)~ *FREDONIA GENEVIEVE ~ LIMESTONE z LIMESTONE z w- ·MEMBER MEMBER z GENEVIEVE t--' LIMESTONE LIMESTONE 1- ~ g LIMESTONE (/) z ~ LOWER 

MEMBER 0 u ~ MEMBER w z 

~ (J)w UPPER _z MEMBER ST. LOUIS ::>0 w gt; ST. LOUIS LIMEz ~ LIMESTONE .w LOWER ST. LOUIS STONE MEMBER 

<( ~--~ LIMESTONE - (/)- MEMBER a.. ' _, 

a.. 

- SALEM SALEM SALEM (/) 

(/) LIMESTONE LIMESTONE AND 

- WARSAW *RENFRO (/) -- WARSAW (/) ULLIN LIMESTONE 

HARRODSBURG FORMATIONS MEMBER 

- r-- LIMESTONE ~ LIMESTONE 

~ 1-- - - - 1-- - f-- ---- f- - - --

FORT FORT PAYNE *MULDRAUGH FORT PAYNE 

PAYNE z FORT PAYNE 

FORMATION FORMATION MEMBER FORMATION 0 CHERT 

~ FLOYDS *WILDIE ~ 

KNOB BED MEMBER a: z 0 *NADA 0 (*HOLTSCLAW 

LL 

~ *HALLS GAP z MEMBER z SILTSTONE 

~ MEMBER w ~ MEMBER c 

(!) a: a: 

<( 0 0 

(/) LL *NANCY *NANCY CXl *COWBELL 

0 z MEMBER MEMBER GRAINGER 

a: w MEMBER FORMATION 

~ c 

a: 

0 GENWOOD *NANCY _, CXl LTSTONE MEMBER 

I\.:1EMBER 

SPRINGVILLE 

. NEW PROVIDENCE NEW PROVIDENCE ~*FARMERS SHALE SHALE SHALE MEMBER MEMBER . 

--------- z SUNBURY ~ CHOUTEAU :at: ROC~ FORD SHALE 

0 LIMESTONE LIMESTONE <( 

0 >- (!) 

:X: z BEREA 0 a: <w ow w ~~ SANDSTONE z~ c HANNIBAL HANNIBAL (MAURY FORMATION 2 <:x: <:x: 

~ SHALE SHALE EQUIVALENT) 

~: BEDFORD 1=(/) 

I- __ SHALE <( 

- - ::c - u 

g~ NEW ALBANY CHATTANOOGA NEW ALBANY CHATTANOOGA OHIO 

~z GROUP SHALE SHALE SHALE SHALE 

FIGURE 4.-S.tratigraphic nomenclature of the Mississ·ippian System in Kentucky and southeastern Illinois. Asterisk ( *) 

·indicates type section in Kentucky. 
F8 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

~ 

EASTERN INTERIOR BASIN I APPALACHIAN BASIN 

en ~ !!I EAST- CENTRAL 

~ ~ WEST- SOUTH- SOUTHEASTERN 

~ WESTERN AND 

en CENTRAL CENTRAL NORTHEASTERN (PINE MOUNTAINf · 

1111111111 r 1 I I II I 11 Ill 7 II II 1111 II lli 7 1111111T 

GROVE CHURCH 

SHALE 

KINKAID Gre LIMESTONE 

EGAP 

DEGONIA MBER 

7 - SANDSTONE 

~ CLORE ~z 

LIMESTONE <C(O PENNINGTON 

~i= 0 z o<C( ..J 0 

PALESTINE Q 

~~ w 

~ ~ FORMATION 

SANDSTONE u.O X u,.U. u :E :::> t: a: 

m w 0 

MENARD . ..J u. . LIMESTONE 

WALTERSBURG 

SANDSTONE 

VIENNA 7 

LIMESTONE STONY GAP 

r--?- SANDSTONE 

z *TAR SPRINGS CARTER MEMBER 

<C( z SANDSTONE CAVES ss. ? 

- <C( Q.. - BANGOR Q.. a: *GLEN DEAN - w LIME· C/) 1- LIMESTONE STONE 

UPPER 

C/) MEMBER 

- C/) HART- C/) w •HARDINSBURG C/) X SELLE 

- u SANDSTONE FORMATION 

~ 7 

HANEY 

LIMESTONE MEMBER 

GOLCONDA *BIG CLIFTY 

FORMATION SANDSTONE MEMBER w 

BEECH CREEK w z z 0 

LIMESTONE 0 ·~ 1- MEMBER en UPPER w w a: w :E 

CYPRESS ELWREN z w :E :J 

0 m :J 

SANDSTONE SANDSTONE 1- ~ z en z <C( 

w w LOWER ~ a: ~ <C( MEMBER ~ w ~ REELSVILLE :J 0 w ! 

LIMESTONE w g z ! z 

! z ..J ~ 0 z CJ • 1-

PAINT CREEK zQ ~ en MEMBER 

•SAMPLE 

~i w 

LIMESTONE ~ 

(SHALE) SANDSTONE z ..J 

CJa: 0 • 0 ~ 

BEAVER BEND u. 

LIMESTONE 

*BETHEL MOORETOWN 

SANDSTONE FORMATION 

RENAULT PAOLI 

LIMESTONE LIMESTONE 

FIGURE 5.-Stratigraphic nomenclature of the Chester Series and equivalent strata in Kentucky. Asterisk ( *) indicates 

type section in Kentucky. 
KENTUCKY F9 

.prograding delta (Chester) : Paoli-Renault 

Limestone through Grove Church Shale of 

western Kentucky; Paoli Limestone through 

Glen Dean Limestone correlatives in the Newman Limestone, Monteagle Limestone, Hartselle Formation and Bangor Limestone of 

south-central and eastern Kentucky. 

4. Terrigenous detrital deposits (dominantly shale, 

varied amounts of s-andstone, .some marine 

limes~tone and dolomite) of westward and 

southwa·rd prograding deltaic systems ( Ghes~ 

ter) : Pennington Formation of ea-stern Kentucky; Buffalo Wallow and Leitchfield Formations of western Kentucky. 

Major source areas for Mississippian terrigenous 

sediments were ( 1) to the northeast, within or beyond the Acadian tectonic belts of the Northeastern 

United States and eastern Canada, and, possibly, 

northern Canada; ~and (2) to the east, within or 

beyond the Piedmont prov;ince of the Eastern United 

States. A third possible source for Upper Mississippian sediments has been reported to the south in 

the area between the Ouachita Mountains of Arkansas and the Black Warrior bas~n of Alabama and 

Mississ;i.ppi (Thomas, 197 4). 

During Kinderhook time, distal deltaic deposits 

(Bedford Shale, Berea Sandstone) prograded southward and westward into eastern Kentucky, spreading across Late Devonian ·carbonac·eous sediments 

(Ohio and Chattanooga Shales) (Pepper and others, 

1954). When progradation ceased, the deltaic depo~its were onlapped eastward and northeastward 

by carbonaceous sediments of Mississippian age 

(Sunbury Shale). Thin distal deposits of shale and 

limestone (Hannibal Shale, Rockford Limestone) 

probably from northern sources are preserved in 

western Kellltucky, but across much of the State, the 

Kinderhook is locally represented only by a very 

thin stratum orf clay shale and phosphatic nodules, 

suggesting starved-basin conditions. 

Osage time was marked by a major renewal in 

westward and southwestward deltaic progradation 

into Kentucky. The lower and middle Borden Formation is a sequence that coarsens progressive from 

deepwater, prodelta clay shale (New ProV:idence 

Shale Member) upward through .silty shale (Nancy 

Member) into siltstone (Holtsdaw Siltstone, Halls 

Gap, and Cowbell Members) ·containing local deltafront turbidite deposits (Kenwood Siltstone, 

Farmers, and W.ildie Members) (Kep.ferle, 1977; 

Moore and Clarke, 1970; Peterson and Kepferle, 

1970; Weir, 1970). The western limit of foreset siltstone forms a remarkably straight, northwestwardtrending Borden delta front, ·extending across westcentral and south-centr~l Kentucky. Water depths 

s·eaward of the front may have ·been as great as 85 m 

(Indiana University, 1972). A depositional hiatus 

following active progradation !iS indicated by the 

presence o.f a thin glauconitic unit (Floyds Knob 

Bed, F,loyds Knob correlative .in Wilde and Nada 

Members) extending across the outer delta plakform 

and slope and into the ba.sin. 

Extensive carbonate deposition began during 

Osage time, partly contemporaneous with but mostly 

following the deltaic P·rogradation, and continued 

through Merame·c into Chester time. The initial 

deposits were argillaceous and siliceous, dolomitic 

siltstone, .silty dolomite, and micro grained . and 

crinoidal limestone (Fort Payne Formation, Muldraugh and lower Renfro Members of the Borden 

Formation), which were deposited seaward (west) 

of the delta front and across the prodelta slope and 

outer delta platform in basinal to supratidal environments. Locally, distinct elongate bodies of limestone and sandstone ('Cane Valley Limestone and 

Knifley Sandstone Memher·s of the Fort Payne Formation) were formed as submarine barrier-shoals 

and banks parallel to and seaward of the delta front 

(Indiana University, 1972). Succeeding bryozoancrinoidallimtes.tone (Harrodsburg and War·saw Limestones) and bioclastic, pelletal, and foraminiferal 

limestones (Salem Limestone) form widespread 

units in western and south-central Kentucky, but 

pinch out northeastward across east-central Kentucky. These units contain varied amounts of dolomitic limestone, shale, and sandstone. The Warsaw 

in western Kentucky has a variable thickness reflecting deposition on the irregular basinal deposits 

of the Fort Payne. The first major cycle of carbonate 

deposition during this period is cap.ped by a sequence 

of tidal-flat and sup·ratidal dolomite and limestone 

containing evaporite deposits (lower St. Louis Limestone, upper Renfro Member of the Borden Formation). 

During renewed transgression •in late Meramec 

tim·e, the initial deposits were subtidal, fossiliferous, 

micro grained, and bioclastic Hmestone (upper St. 

Louis Limestone), succeeded by shallow subtidal 

oolitic and bioclastic limestone (Ste. Genevieve 

Limestone). In western Kentucky, subsidence virtually in equilibrium with basin filling probably began in St. Louis time or som·ewhat earlier and continued through the remainder of the M~ississ.ippian 

Period. Carbonate deposition was interrupted at the 

end of Meramec time by a period of widespread exposure. A prominent zone o.f altered limestone 
FlO THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

(Bryantsville Breccia Hed) formed during subaerial 

exposure and vadose diagenesis at the toip of the 

Ste. Geneieve throughout much of its out-crop belt 

across the State. Episodes of renewed activity along 

the early Paleozoic Waverly arch and Kentucky 

River fault system interrupted St. Louis and Ste. 

Genevieve deposition in northeastern Kentucky and 

were followed by a period of extensive erosion ·On 

the upthrown (northern) side of the· fault system. 

During Chester time, about 370 m of rhythmically 

alternating carbonate and terrigenous detrital units 

accumulated in western Kentucky !in very shallow 

water. Carbonate sediments were deposited on a 

broad shallow marine shelf; terrigenous sand and 

clay were brought in ·by prograding deltaic lobes of 

the Michigan River, which intermittently encroached southward .into the shallow shelf environment (Potter, 1963; Swann, 1963, 1964). Elongate 

sandstone hodies were probably mainly of distl'libutary origin, ·conrtaining one or more tidal-channel 

deposits (Mooreto,wn-Bethel) ; widespread shale was 

delta platform clay and prodelta clay. Thin coal was 

formed locally. Late·ral shifting of the M·ichigan 

R:iver system ac~oss central Illinois and Indiana was 

a controlling facto·r that determined gross variations 

in detrital sediment distr.ibution in Kentucky; 

periodic dimatic or tectonic oscillations in source 

areas controlled the volume of detrital input .into the 

Eastern Interior basin. The Cincinnati and Ozark 

arch areas were relatively positive features, posSiibly 

shoals or emergent lowlands, whi.ch partly controllea 

the axis of detrital deposition ( S.wann, 1963, p. 15). 

Major shoreline fluctuations, combined with diminished detl'!ital supply, contributed to widespread 

carbonate deposition .. between times of maximum 

detrital deposition. The 'Proportion of shale and 

sandstone to limestone generally increases northward across western Kentucky and upward within 

the Chester succession. 

In southern and eastern Kentucky, lower and 

middle Ches·ter units and their correlatives are dominantly limestone; detrital units that are relatively 

thick and extensive in western Kentucky commonly 

are represented only by thin deposits of shale. S'andstqne (Hartselle Formation) possibly derived from 

a southern source area, extends into south-central 

Kentucky from Tennessee and may have been deposited as a barrier island or an offshore bar 

(Thomas, 1974). Limestone of lower Chester age 

contains · several zones of alteration that were 

formed :in part during ·prolonged exposure and diagenesis of tidal-flat and supratidal deposits capping 

a series of fining-upward sequences. In northeastern 

Kentucky, the distribution of lower Chester correlatives reflects deposition on the post-Ste. Genevieve erosional surface and the persistence of the 

Waverly arch (see structure map, fig. 15) as a positive f.eature. In southeastern Kentucky, the Meramec 

and lower through middle ( ?) Chester ·correlatives 

exposed along Pine Mountain consist of very thick 

depos,its of shelf limestone and thin shale. These deposits indicate that shallow marine carbonate deposition kept pace with the relatively rapid subs,idence of this part of the Appalachian basin. 

During latest Chester time, terrigenous detrital 

depos~its (Pennington Formation ; upper Newman 

Limestone (Englund and Windolph, 1971)) of westward-prograding deltaic systems spread across eastern Kentucky. The change from. ·carbonate deposition to deltaic detrital deposition was gradual; the 

upper part o.f the carbonate succession .contains increased am.ounts o.f interbedded shale and argillaceous lim·estone. The Pennington is dominantly 

shale containing varied amounts of sandstone, some 

limestone and dolomite, and minor coal, rep.re.senting 

offshore-bar, lagoonal, tidal-flat, estuarine, distributary, and coastal-marsh de.posi:ts. Southeastward, 

sandstone becomes. a major constituent o.f the Pennington. A linear sandstone body (Carter Caves 

Sandstone) in northeastern Kentucky i~s described 

variously as an offshore bar (Englund and Windo,lph, 1971), a beach-barrier island system (Horne 

and other.s, 1974), or a tidal-·channel deposit paralleHng the Waverly arch (Ettensohn, 1977, p. 18-29). 

In west-central Kentucky, the upper 'part of the 

Chester succession (Buffalo Wallow and Leitchfield 

Formations) in the eastern part of the Eastern Interior basin is lithologically similar to the Pennington of eastern Kentucky. The geographic proximity 

and l~itho1ogic similarity o.f these approximately correlative units suggest that the Buffalo Wallow and 

Leitchfield may contain detrital rooks der.ived from 

both the southward-prograding Michigan River and 

westward-prograding Pennington deltaic systems. 

BIOSTRATIGRAPHY 

Taxonomy and zonation of m.egafossils in M~issis- · 

s.ippian rocks stem from extensive early studies in 

Kentucky and adjacent States by Stuart Weller 

(1920, 1926), J. M. Weller (1931), Butts (1915, 

1917, 1922), and Ulrich (1917), and others. These 

studies were reviewed and updated by Weller and 

Sutton 1940) . Crinoids, brachiopods, blastoids, 

bryozoans, soHtary and colonial corals, and echinoids 

are dominant forms in the Mississippian assemblage; pelecypods, gastropods, and trilobites are 
KENTUCKY F11 

locally abundant. Crinoid studies by Horowitz 

( 1965), and biofacies studies of a Ghester rock unit 

(Vincent, 1975) are two exa·mples of the many 

selective studies done in recent years. 

A significant change in the crinoid fauna marks 

the Chester-Meramec series boundary in western, 

west-central, and south-central Kentucky-the 

change from PlatycTin'ites penicillus Meek and 

Worthen, a Merame·c form, to Tala'rocrinus spp., a 

Chester form. The fauna ·change corresponds to the 

time of formation of a widespread zone of altered 

limestone (Bryantsville Breccia Bed) interpreted to 

have developed during subaerial exposure and diagenesis. Other Mississ·ippian boundaries and the 

Devonian-Missis.sippian syste.mic boundary appear 

to occur within intervals of continuously deposited 

strata, and faunal criteria .for specific boundary demarcation are not conclusive. However, many specific and generic forms have proved valuable aids in 

practical rec·ognition and mapping o.f stratigraphic 

units. Figure 6 shows general strat·igraphic occurrences o.f selected fossil faunal elements that have 

been successfully used in ma:pping Mississippian 

rock units in Kentucky. The list is incomplete and 

does not show faunal ranges. 

Microfossils in Mississippian rocks of Kentucky 

include endothyrid and paleotextulariid Foraminifera, conodonts, and ostracodes. Although no syste·matic studies have been done for the entire system 

in Kentucky, foraminiferal studies -include those by 

Browne and Pohl ( 1973), Browne and others 

(1977), Conk·in (1954, 1956, 1961), Pohl and others 

( 1968), and Pohl ( 1970). Conodont studies, following z.onation used in the Mississippi Valley (Collinson and others, 1962, 1971), include those by Rexroad (1958, 1969), Nicoll and Rexroad (1975), Rexroad and Liebe (1962), and Howoritz and Rexroad 

(1972). 

The zonation of plant megafossils :in western Kentucky and adjacent States of the Eastern Interior 

basin has established criteria for distinguishing Miss·issippian sandstone from l·ithologically similar 

Pennsylvanian strata (Jennings, 1977). A rare lycopod occurrence in the· basal St. Louis Limestone of 

west-central Kentucky was reported by Browne and 

Bryant (1970). 

MISSISSIPPIAN-PENNSYLVANIAN BOUNDARY 

The M·ississippian-Pennsylvanian boundary along 

the margins of the W es•tern Coal Field and northwest margin of the Cumberland Plateau has long 

been ·interpreted to represent a regional unconformity (Miller, 1919, p. 252). Extensive subsurface 1 

work by Bristol and Howard ( 1971) in western 

Kentucky helped to identify a general northward 

and northeastward truncation of progressively older· 

Mississippian strata and several broad southwesttrending sub-Pennsylvanian valleys (fig. 7). These 

valleys or channels are •incis·ed as much as 75 m 

into the ge11tly rolling plain of the truncated Mississippian surface and may locally represent removal 

of more than 275m of Mississippian strata. Detailed 

studies of parts of these channels have been made 

by Davis and others (1974) and Shawe and Gildersleeve ( 1969). Extending eastward from the easternmost channel shown in figure 7 is a tongue of 

conglomeratic sandstone that has been interpreted 

by Burroughs ( 1923) as the remnants of a "Potts-· 

ville-filled channel" resting on rocks as old as the 

St. Louis Limestone (Mississippian). 

In the narrow outcrop helt along the western edge 

of the Cumberland Plateau of eastern Kentucky, the 

unconformity ·is marked ~by channels as much as 60 

m deep and locally by paleokarst topography developed on Mississippian limestone. The sub-Pennsylvanian surface (fig. 8) also shows a north or northnorthwestward tru!lcation of Mississippian strata, 

probably reflecting the influence of the Cincinnati 

and Waverly arches at that time (Englund, 1972) .

1 

The existence of the Mis·sissippian-Pennsylvanian 

unconformity in northeastern Kentucky was challenged by Horne and Ferm ( 1970), Horne and 

others (1971), Ferm and others (1972), Ferm 

(1974), and Horne and others (1974), who attempted to show the relations·'-lip of the largely terrestrial Pennsylvanian deposits (Lee and Breathitt 

Format-ions) above the unconformity to the underlying marine Mississippian strata by means of a 

dep-ositional model. If correct, their thesis· is highly 

s·ignificant in considering the age and stratigraphic 

relations of many Carboni·ferous units .in the Appalachian and midcontinent area. Their depositional 

model, ·called the "Lee-Newman barrier shoreline 

model" (Horne and others, 1971), identifies orthoquartzite (commonly Lee Formation) as be~ch-barrier deposits that grade landward into lagoonal and 

lower deUa-plain shale, subgraywacke, and ·coal 

(Breathitt Formation) and seaward into red and 

green marine shale (Pennington Formation and 

N-ada Member of Borden Formation) that surrounds 

offshore c~rbonate islands (Newman Limestone). 

1 Strata in northeastern Kentucky identified as Pennington by various 

workers have been assigned to the Newman Limestone by Englund and 

Windolph ( 1971). The relations of these rocks, generally less than 10 

m thick, to strata of the Penni'llgton Formation in south-central Kentucky, as much as 50 m thick, or those in the type area of Cumberland 

Mountain, as much as 350 m thick, are uncertain. 
F12 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Cl) 

w 

a: 

w 

Cl) 

<( 

a: 

w 

f-7-

w 

~~ WI- -JCJ) 

<Cw 

CJ)~ 

::::; 

-

w 

CJ)I- ~~ a:CJ) 

<(W 

~~ _, 

""¥Z-

>e z if !;t 

<( li: ~ w lftf2 C!J 

<( 

Cl) 

0 

WESTERN 

Spirifer increbescens Hall 

Composita subquadrata (Hall) 

Sulcatopinna missouriensis 

Pterotocrinus spp* 

Archimedes spp* 

Talarocrinus spp. 

Lithostrotion (Siphonodendron) 

genevievensis 

Platycrinites penicillus Meek and 

Worthen 

"Lithostrotion" proliferum Hall* 

Lithostrotion castelnavi Hayasaka* 

Melonechinus sp. 

Syringopora sp. 

Endothyra baileyi Hall 

Hapsiphy/lum sp. 

Brachythyris subcardiiformis(Hall) 

Echinocrinus sp. * 

Spirifer latera/is 

Pentremites conoideus 

Talarocrinus sp. 

-

~~ =>O 

g~ .w 

~--~ CJ)::::; 

-

-I U.O 

(I) z CtllC ca:l- a:::lcn 

~~~~~ :1: ::::; 

-

z zo 

Wj:: 

0<( 

a:~ 

Oa: 

me u. 

WEST-CENTRAL 

Spirifer increbescens Hall 

Composita subquadrata Hall 

Pterotocrinus spp. * 

Prismopora sem.ilata Ulrich 

Archimedes spp. * 

Archimedes spp. * 

lnflatia inflata (McChesney)* 

Agassizocrinus spp. 

Lithodromus veryi (Greene) 

Talarocrinus spp. 

Lithostrotion (Siphonodendron) 

genevievensis 

Platycrinites penicillus Meek and 

Worthen 

Zz 

co 

1-p: 

(!)<( 

~~ Za: 

zo 

~u. 

- "Lithostrotion" proliferum Hall* !!?~ 

Lithostrotion caste/navi Hayasaka* 8~ 

Melonechinus sp. ~~ 

Archeocidaris sp. 

Syringopora sp. 

Endothyra bail~yi Ha II 

Brachythyris subcardiiformis (Hall) 

Hapsiphyllum sp. 

Marginirugus magnus 

Orthotetes keokuk (Hall) 

Syringothyris textus (Hall) 

Very large crinoid stem segments* 

f--'---

CJ) ~ 

a:CJ) 

<Cw 

~z 0 01- ZC/) 

<(W 

~ ~::::; 

w 

CJ) ~ 

SOUTH-CENTRAL 

AND 

EAST-CENTRAL 

Pterotocrinus spp. 

Archimedes spp. * 

Large crinoid· stem segments* 

Pentremites spp. * 

Agassizocrinus spp. 

Talarocrinus spp. 

-------

Platycrinites penicillus Meek and 

Worthen 

"Lithostrotion" proliferum Hall 

Lithostrotion castelnavi Hayasaka 

Syringopora sp. 

Hapsiphyllum sp. 

Spirifer latera/is 

Very large crinoid stem segments* 

FIGURE 6.-Stratigraphic occurrence of selected Mississippian fossil fauna, on the basis of general abundance 

and ease of recognition, that are helpful in recognition of map units in Kentucky. Asterisk denotes very 

abundant; shaded areas denote intervals of largely terrigenous detrital strata. 
KENTUCKY 

They interpreted the dntra- and post-Mississippian 

erosional unconformities, described by previous 

workers, to be depositional or facies-controlled 

boundaries. 

Central to the development of the Lee-N·ewman 

model is a cross section of Carboniferous rocks ex311" 

--

811" 

I 

1

1 

50 

50 

I 

87° 

100 MD.ES 

I 

86" 

_j -~----~-------------

39" 

311" 

37° 

85" 

EXPLANATION 

Pennington 

Fonnatlon 

Newman 

Limestone 

840 83" 

-----.:..K.Y ____ ~~ 

TENN 

I '• 

~0 

50 

I 

I 

100 KILOMETERS 

100 MILES 

I 

F13 

FIGURE 7.-Sub-Pennsylvanian valley systems in the western 

Kentucky coal field. 

FIGURE 8.-Generalized geologic map of the pre-Pennsylvanian 

surface in the northwest part of the Cumberland Plateau, 

eastern Kentucky. 

West A 

0 2 MILES 

West 

t_. I !"'TI--'--.-1 _ ___, 

0 1 2 KILOMETERS 8 

·Lee and Breathitt Formations, undivided 

East 

Breathitt Formation 

Modified from Ferm and others (1971, fig. 131 

and Home and others (1974, fig. 21 

East 

lji~ =-=- ~ ----!1-~-~ 11 ~=~~=-===~=-=. =~=~~=~=~~==~ =~~=~~ ~=~ ==~:ir~~;~£.~=-~~=T ~~~~~~== ==.~:.=~= ~~-:-::~. :_·:. :_:_: : :-:--:-::::::: 

Orthoquartzite sandstone 

Limestone 

Dolomite 

EXPLANATION This report 

~ Red and green shale 

~ Siltstone 

c=J Sandstone, siltstone, and shale 

undifferentiated 

FEET METERS 200 

50 

FIGURE 9.-Generalized cross sections showing two interpretations of Carboniferous rocks exposed along Interstate Highway 

64, eastern Rowan and western Carter Counties, northeastern Kentucky. 
F14 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

posed along Interstate Highway 64 in northeastern 

Kentucky. Relations between rock units along part 

of the highway as interpreted by Ferm and others 

(1971, fig. 13) and Horne and others (1974, fig. 2) 

are shown in fig. 9A. The intertonguing of a thick 

sequence of marine shale (Pennington and Nada) 

with two isolated bodies of carbonate rocks (Newman) and lenses of orthoquartzite (Lee) is intended 

to show a west-migrating shoreline environment. 

The proposed depositional model is untenable in 

view of field relationships betw·een lithologic units 

in the area. Study of exposures along the interstate 

highway by the present writers h'as estabHshed the 

presence o.f erosional remnants and lithologic sequences that .indicate the former continuity o.f carbonate units across the area (fig. 9B). No intertonguing of limestone and shale along the margins 

of the carbonate bodies was seen. Red and green 

shaJes. ~in the road seotion were found to belong to 

the Nada Member of the Borden Formation and two 

thin ·shale units in the Newman Limestone; the 

·measured thicknesses of these shales are less than 

·half· that indicated in figure 9A. In the authors' 

opinion, the distribution o.f rock units shown in 

figure 9B reflects. erosional and depositional thinning related to two regional unconformities that 

have ·been described by Dever and others (1977), 

Patterson and Hosterman (1962), and Sheppard 

(1964). The lower unconform•ity followed deposition o.f the basal limestone unit of the Newman and 

locally ·cuts into the Cowbell Member of the Borden 

Formation. ·The upper unconformity is Mississippian-Pennsylvanian; it is overlain by deltaJic carbonaceous shale .and siltstone containing minor 

sandstone bodies that are dominantly fluviatile in 

origin. The unconformity has a local relief of about 

25 m; total thickness of missing Mississippian strata 

may be ·more than 50 m. 

In southeastern Kentucky, the Mississippi-Pennsylvanian systemic boundary occurs in the upper 

part o.f the Pennington Formation in an intertonguing and intergrading sequence of siltstone, 

sandstone, and shale: strata above are largely continental, and those below are largely marine. Englund (1974, p. 38) identified a major Pennsylvanian 

unconformity at the base of the New River Formation in Virginia and West Virginia and at the base 

of the Middlesboro Member of the Lee Formation 

in southeastern Kentucky. (See fig. 12.) He showed 

that this unconformity cuts progressively older 

strata northwestward and suggested that it coincides w.ith the widespread Mississippian-Pennsylvanian unconformity of the midcontinent region. 

PENNSYLVANIAN STRATA OF EASTERN 

KENTUCKY 

The Pennsylvanian rocks of eastern Kentucky 

form a clastic wedge that thickens southeastward 

toward the axis of the Appalachian basin. The· rocks 

crop out in an area of about 27,000 km2 and occupy 

a central part of the Appalachian coal field that extends from New York to Alabama. 

The depositional ·character of the Pennsylvanian 

strata is deltaic. The lower part generally is dominated by thick orthoquartzite and the upper part 

by siltstone, shale, and generally thin discontinuous 

subgraywacke. Although only a few widespread 

marine transgressions. took. place during ·Pennsylvanian Ume, many coal beds are overlain by shale 

that locally contains sparse brackish-water or marine fauna. 

GEOLOGIC SETTING 

By Late Mississippian time, eastern Kentucky was 

the site of shallow-water clastic deposition, which, 

except where interrupted by the formation of 

swam.ps, continued throughout Pennsylvanian time. 

In southeastern Kentucky, or the central part of the 

basin, continuous deposition took pJ.ace across the 

systemic boundary, while to the northwest, basal 

Pennsylvanian sediments were disconformably deposited on the eroded Mississippian surface. 

Pennsylvanian deposition was strongly influenced 

by the rapidly subsiding Appalachian trough, whose 

axis was southeast of and generally parallel to the 

strike of P·ine and Cumberland Mountains. The cross 

section in figure 10 shows the great thickening of 

sedimentary r-ocks toward the axis of the trough. 

Figure 11 illustrates the influence of the subsiding 

trough on deposition of part of the Breathitt Format,ion. Campbell (1898) thought that much o.f the 

northwestward thinning of Early Pennsylvanian 

strata was due to onlap and that as much as onequarter of the basal Lee section is not present in 

outcrops of the Pottsville escarpment along the western border of the basin. 

Most Upper Pennsylvanian rocks have been 

eroded from eastern Kentucky, except for those 

preserved in a broad syncline in northe·astern Kentucky. (See fig. 15.) Although the section locally 

may be thick enough to include Perm,ian strata, 

such have not been identified. 

STRATIGRAPHY 

The Pennsylvanian strata of eastern Kentucky 

comprise locally .part of the Pennington Fonnation 
Bordley 

section 

Unnamed 

limestone 

zone 

Sulphur 

Springs 

coal 

Geiger 

lake coal 

Carthage 

limestone 

c: 

0 

·w 

.f 

·~ 

~ ~ 

~ 

Carthage Limestone 

~~~ Madisonville Limestone _1 I 

c: 

§ 

c: 

f 

~ ~ No.11 coal -~ -g -2 No. 9 coal l, 

~ ~ No. 6 coal _ J. 

~ 

Jl 

----------------- f.,_ Unnamed limestone ~ 

!a Curlewlimestone ---------------------

/ ~ -~ No. 4 coal Lead Creek Limestone ig 

:: ~tb~:_-. .-.~_:S0%88@IT:,,,?,,;_~ ... : .. : ... ~---~-.: ... ,:.,.:. __ ;:_._,=,._,~,.: .... ... ~ :. :.77-T-7.~ =.9 

~= "'E 

~0 <.JLL 

Tar Springs Sandstone Top Glen Dean Limestone 

METERS FEET 

300 f 1000 

200 

100 

800 

600 

400 

200 

10 '20' 30 40 MILES 

Hi 20 30 40 50 60 KILOMETERS 

0 50 100 MLES section 

0 50 100 150 KILOMETERS 

EXPlANATION 

1521 Limestone 

~ Cherty limestone 

ILI] Orthoquartzite 

E3) P~bbly orthoquartzite 

D Subgraywacke, sitstone, and day shale 

ffi Coal bed with underday 

.2' 

a 

j 

....: 

[iJ 

log Mountain section 

showing named 

·coal beds 

FIGURE 10.-Genera.lized. cross sections of the Pennsylvanian of eastern and western Kentucky. Missing section above -land surface ·across Cincinnati arch 

represents a gap of about 200 km. Anticlinal structure· in eastern Kentu-'!ky cross section is only apparent and is due to placement of section line. Sandstone of the Log Mountain section is subgraywacke except that of the Lee Fonnation. 

~ 

tr=J 

z 

t-3 

~ 

0 

~ 

~ 

~ 

1-L 

~ 
F16 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

39" 

as• 84" 

EXPLANATION 

Isopach 

Dashed where projected; 

contour interool 25 meters 

Thrust fault 

38" Sawteeth on upper 

plate 

37" 

83" 

1

1

1 1

1 

I \ 

&1 

I 

50 100 KILOMETERS 

82" 

OHIO 

100 MILES 

I 

FIGURE H.-Isopach map showing interval between the base 

of the Kendrick Shale of Jillson (1919) and the base of the 

Magoffin Member of the Breathitt Formation in eastern 

Kentucky. 

and all the overlying Lee, Breathitt, Conemaugh, 

and Monongahela Formations. 

PENNINGTON FORMATION 

The upper part of the Pennington Formation in 

southeastern Kentucky contains Pennsylvanian flora 

(Maughan, 1976). The Mississippian-Pennsylvanian 

systemic boundary there occurs in a gradational 

sequence between the highest marine unit (LUtle 

Stone Gap Member o.f the Pennington Formation of 

M~ississippian age) and the base of the Middlesboro 

Member of the Lee Formation. This sequence includes reddish-, greenish- and dark-gray clay shale, 

gray and brownish-gray siltstone, ·coarse- to finegrained pebbly orthoquartzite, and fine-grained silty 

sandstone. Thin coal beds and underclay that occur 

near the top of the Pennington are truncated locally 

by the Middlesboro Member of the Lee Formation 

in southeastern Kentucky. 

LEE FOR!MA TION 

The Lee Formation is characterized by massive 

pebbly orthoquartzite that locally contains lens·es of 

conglomerate; in places, sandstone makes up more 

than 80 percent of the formation. In extreme southeastern Kentucky, :the unit is locally more than 500 

m thick and has been divided into· eight members, 

six of which, the Pinnacle Overlook, Chadwell, White 

Rocks, Middlesboro, Bee Rock Sandstone, and N aese 

S-andstone Members, are dominantly :sandstone 

(Englund, 1964). The other two, the Dark Ridge 

and Hensly Members, consist generally of carbonaceous siltstone and shale, thin bedded subgraywacke, 

and coal. Figure 12 shows the relations of these 

units in various parts o.f the Cumberland overthrust 

block. 

Along the PottsviUe escarpment, only the extensively mapped and named pebbly orthoquartzite 

units are ass~igned to the Lee Formation : the 

Livingston Conglomerate, Rockcastle Sandstone, 

Corbin Sandstone, and Grayson Sandstone Members. 

Other quartzose sandstones occur between these 

named members, but they are generally thin and 

discontinuous, and all pinch out into or locally intergrade with siltstone or subgraywacke of the Breathitt Formation. 

The Lee Formation :is composed of a series of 

broad orthoquartzite lobes generally oriented northeast, generally parallel with the axis of the Appalachian basin and showing a dominant sbuthwest 

transport direction (Potter and Siever, 1956 a and 

b; Englund and Delaney, 19·66; Englund, 197 4). The 

orthoquartzite lobes· of the Cumberland overthrust 

block intertongue with or grade into nonresistant 

subgraywacke to the southeast in southwestern Virginia, and siltstone ·and subgraywacke to the northwest (Englund, 1968, pl. 5). The thickest part of 

each successive s·andstone member is farther northwest, and in places it ·cuts into the older sandstone 

member. Thus, the top o.f the Lee Formation is 

placed at strat·igraphically higher levels toward the 

northwest as shown in figure 13. 

Ferm (1974, p. 94) and Donaldson (1974, p. 48) 

suggested that the Lee Formation of ·eastern Kentucky is a beach-barrier and back-barrier complex 

of northwestward ... migrating shoreline environments. They suggested that the dominant southwest 

current direction of these strata was caus·ed by longshore currents and southwestward migration of tidal 

channels. However, the marine rocks that should be 

associated with a beach or barrier system., are rare 

in the Lee Formation or intercalated Breathitt 

strata. On the contrary, the Rockcastle and Corbin 

Sandstone Members pinch out into deltaic siltst;one 

and sandstone. Pennsylvanian strata underlying the 

Rockcastle and Corbin consist dominantly of car-
KENTUCKY F17 

~ NORTHEASTERN CENTRAL AND SOUTHEASTERN CUMBERLAND SOUTHWESTERN lii 

>- PINE MOUNTAIN PINE MOUNTAIN MOUNTAIN VIRGINIA 

en 

NAESE MEMBER / NAESE MEMBE~ UPPER 

MEMBER / BEE ROCK MEMBER BEE ROCK MEMBER 

z SANDSTONE NEW RIVER 0 z AND SHALE 

~ 0 HENSLEY MEMBER MEMBER HENSLEY MEMBER FORMATION MIDDLE MEMBER ~ D z 

~ ~ 0 

z a: ~ ~ f2 a: 

~ 0 SANDSTONE ~ 

w u.. MIDDLESBORO a: ..J 

~ w MEMBER 0 >- MEMBER u.. en w c z LOWER ..J MIDDLESBORO w z . w 

w MEMBER MEMBER ..J 

Q. SANDSTONE 

AND SHALE DARK RIDGE MEMBER 

MEMBER 

__ B_ __ _/WHITE ROCKS 

~ SANDSTONE "· "- MEMBER POCAHONTAS 

MEMBER FORMATION 

z z CHADWELL MEMBER Q 0 A 

< i= 

a: 

~ ------ <t 

a: 

~ .___ --- _T_ ----- ~ 

f2 lt Zz BLUESTONE FORMATION 

z ~Q z :$ z z 0 

R: ~ 0 LOWER TONGUE OF PINNACLE OVERLOOK (!)< I-ll. 1- MEMBER OF ?;~ PRINCETON FORMATION (!)::::> 

iii (!) (!) LEE FORMATION zo !!2 z z LEE FORMATION Za: -a: en z z -- ~lt ~(!) !!2 z z w 

::E It w HINTON FORMATION Q. Q. 

FIGURE 12:.-Correlation chart of the Lee Formation in southeastern Kentucky and southwestern Virginia. 

bonaceous shale and siltstone that contain plant material and coal beds, and seat rocks that contain 

abundant root im.pressions. Some of these basal 

strata consist of coarsening upward sequences that 

range from 1 m to as much as. 10 m in thickness. 

Evidence of bioturbation is common, but few brackish-water or marine fauna are present. The sequences do not persist laternlly more than a few 

kilometers and p·rohably were deposited in small 

shallow interdistributary bays associated with lower 

delta-plain deposits. The lithology and interrelations 

of the lower part of the exposed Pennsylvanian section suggest that the sandstone m.embers of the Lee 

Formation were large s·and-filled distributary channels of a dominantly southwest-prograding delta. 

BREATHITT FORMATION 

The Breathitt Formation crops out over most of 

the eastern coal field. 2 The Breathitt has been locally 

ranked as a group and has ·been divided into· formaD The name "Pottsville" has been generally applied to these rocks and 

the underlying Lee Formation. Phalen (1912) had defined the Pottsville 

and Allegheny Formations in Kentucky as they were generally used in 

Ohio and Pennsylvania; McFarlan (1943) raised both these units to 

ser!es rank. The Breathitt Formation is equivalent to the upper part of 

the Pottsville Formation and all the overlying Allegheny Formation; 

the top of the Pottsville has not been identified in Kentucky but is 

thought to occur at about the position of the Princess No. 5 coal bed 

in northeastern Kentucky. 

tions on the basis of key beds, but. as these formations are all lithologically alike, they are not differentiated in the following discussion. Regionally, the 

Breathitt and generally underlying Lee Formation 

intertongue. In most areas, the base of the Breathitt 

is placed at the top of the uppermost cliff-forming 

orthoquartzite, but along the Pottsville escarpment 

all Pennsylvanian strata except for the named members of the Lee Formation having regional extent 

are assigned to the Breathitt Formation (Weir and 

Mumma, 1973). 

The Breathitt Formation is as much as 950 m 

thick in ,southeastern Kentucky but is preserved in 

its entirety only 'in northeastern ·Kentucky, where 

it is about 250 m thick. The formation is characterized not only by large differences in thickness but 

also by rapid lateral changes in lithology. These 

characteristics have made bas'in-wide correlations 

difficult, particularly in the lower part of the section. The formation contains most of the minable 

coal in eastern Kentucky. Coal occurs in as many as 

30 major coal beds or coal zones to which more than 

150 names have been appHed; some of the most 

widely used names are included in figure 13. 

The formation consists of siltstone and clay shale, 

subgraywacke, coal, ironstone, and limestone. Siltstone and clay shale intergrade, are commonly car~ 
F18 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

NORTH 

!PRINCESS AND LK:KING RIVER 

COAL RESERVE DISTRICTS) 

TOM COOPER, VAN LEAR, OR 

LmLE CANEY COAL 

GRASSY COAL 

EAST 

IBIG SANDY COAL RESERVE 

DISTRICT I 

SOUTHWEST 

!HAZARD AND SOUTHWESTERN 

COAL RESERVE DISTRICTS) 

SOUTHEAST 

IUPPER CUMBERLAND RIVER 

COAL RESERVE DISTRICT) 

FIGURE 13.-C<>rrelation chart of the Pennsylvanian of eastern Kentucky showing coal beds and other key beds. Members of 

the Lee Fonnation are shaded. Coal reserve districts from Huddle and others (1963). 
KENTUCKY F19 

bonaceous and contain plant fragments; some thin 

zones contain brachiopods, pelecypods, ·cephalopods, 

gastropods, and crino·ids. The subgraywacke is com.-

monly fine grained, and grades into· siltstone; it is 

characteristically micaceous and quartz rich (55 to 

70 ·percent). Ironstone occurs principally as sideritic 

concretions in thin discontinuous lenses or nodules 

in siltstone or shale; iron ores in the form of silty · 

to sandy siderite or limonite occur as J><?ds generally 

less than 50 em thick at the base of the formation 

and in the upper part of the section in northeastern 

Kentucky. Calcareous rocks occur as rare concretionary zones in sandstone and as s~mall to large argillaceous concretions in siltstone and shale; the latter 

are commonly associ a ted with marine horizons but 

may not contain fossils. 

The Breathitt Formation is not readily divisible 

into lithologic units. 'Subdivision of the formation 

is based on the recognition of key beds, generally 

coal beds and marine zones and, because· single beds 

do not :persist acro·ss the entire basin, on sequences 

of key beds. The Fire Clay coal bed with its distinctive hard flint-clay parting was the first to be 

recognized as an ,i,mpo·rtant key bed, and has been 

used extensively as a structure horizon. The flintclay parting, as much as 40 em thick, is reportea to 

contain sanidine and may be the ·alteration p~roduct 

of a volcanic ash fall (Seiders, 1965) . Other coal 

beds are locally useful as key beds, particularly commercial ·CQal beds that have wide extent and are exposed by mining O'perations. 

The best stratigraphic tools for the ·correlation 

and :subdivision of the Breathitt Fo.rmation are 

marine zones several of which are of wide extent. 

The most 'i.mportant are the Magoffin Membe·r, the 

Kendrick Shale of Jil.Ison (1919), and the Lost 

Creek Limestone of Morse (1931). These units resemble one another in their lithologic character and 

are comparable to the marine ,parts of Weller's 

cyclothem (in Wanless and Weller, 1932, p. 1003). 

They are an up·ward-coarsening, bay-fill sequence of 

argillaceous and sandy sediments from 1 to as much 

as 35 m in thickness that were depos,ited after rapid 

marine transgressions over very extensive flat 

shelves. The lower part of the marine deposits is a 

dark-gray fossiliferous clay shale that locally contains thin beds or concretions of fossiliferous nmestone. These beds grade upward into gray siltstone 

containing thin discontinuous lenses of siderite. The 

marine zones commonly overlie a coal bed ; the top 

is marked by an unconformity, generally at the base 

of a channel-fill sandstone or :at the base of a coal 

bed. 

None of the named marine zones extend across tbe 

entire coal field, and few have been identified in 

more than a small part of it. The Magoffin Member 

has the widest distribution, but it too becomes thin, 

discontinuous, and ferruginous along what is interpreted to have been the margins of its bay in northeastern Kentucky. 

Marine invertebrate fossils are present in many 

parts of the Breathitt Formation, but they are unusual in any given section. Most occurrences other 

than in the named marine zones are thin, indistinct 

and sparsely fossiliferous marine bands in siltstone 

and shale sequences that have little continuity 

(Eagar, 1973). These marine bands do not coincide 

with changes of lithology and are probably related 

to changes in salinity in small shallow bays or tidal 

channels. Because many marine zones in eastern 

Kentucky are not associated with large open bay 

deposits such as the Magoffin, they must have 

formed at least 50 km, and perhaps more than 75 

km, from such environments. 

In the eastern and southeastern parts of the basin, 

the marine zones in the lower part of the Breathitt 

below the Magoffin are more numerous, thicker, 

more continuous, more fossiliferous and contain a 

larger variety of fossil fauna. This distribution suggests that open marine waters reached eastern Kentucky from the south and southwest along the axis 

of the subsiding Appalachian geosyncline rather 

than from the north and northwest as has been sug1 gested by Donaldson (1974) and by Horne and 

1 others (1974). Similar conclusions were reached by 

Nelson (192·5) with regard to rocks of the same age 

in southern Tennessee. Only in strata above the 

Magoffin did marine transgressions enter the basin 

fro·m the west and north. The V anport Limestone as 

used by Phalen (1912) and younger Pennsylvanian 

marine zones oc-cur only in northeastern Kentucky 

and are related to southward- and southeastwardtransgressing seas. 

Thick ( 10 to 40 m) sandstone deposits of the 

Breathitt are generally less massive and resistant 

than the orthoquartzite of the Lee Formation. They 

appear to be stacked deposits of shallow anastomosing ~streams. Channel cuts deeper than 5 m are rarely 

observed. Grain size varies from sandstone set to 

set, commonly from bed to bed; only the uppermost 

channel deposit has in its upper part the fining·-upward sequence characteristic of the classic fluviatile 

deposit. Thick sandstone deposits commonly show 

rap,id lateral lithologic changes and rarely form 

mappable units, and even the named sandstone mem-
F20 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

bers are difficult to recognize short distances from 

their type areas. 

The distribution of sandstone and shale in the 

Breathitt Formation has. not been studied systematically. Analyses of small areas support general 

im.pressions that the lower part of the Breathitt is 

dominantly siltstone a;nd shale, and the upper part 

mostly sandstone (Huddle and Englund, 1966). In 

an eight-county area across the central part of the 

coal field, the line of greater than. 50 percent sandstone follows and generally encloses the outcrop of 

the upper part of the Breathitt as it is preserved 

along the axis of the broad eastern Kentucky .syncline (Newell 'and Rice, 1977). (See fig. 15.) The 

sandstone content also apparently •increases in the 

lower part of the formation in the easternmost. part 

of the State. Subangular quartz grit and wellrounded quartz pebbles in coarse-grained sandstone 

occur locally in two areas along the margins of the 

State: in the Jesse and Reynolds Sandstone Members in the middle Breathitt in the northeastern part 

of the Cumberland overthrust block, and in the upper Breathitt in northeastern Kentucky. Current 

directions in the Breathitt have not been studied, 

but sediments probably were derived from Appalachian highlands to the east and southeast. 

CONEMAUGH AND MONONGAHE.LA FORMATIONS 

The Conemaugh and Monongahela Formations are 

not separately differentiated in Kentucky because of 

their lithologic ·similarity. In other areas of the Appalachian basin, the Conemaugh is defined as extending upwards from the top of the Upper Freeport 

coal to the base of the Pittsburgh coal. In Kentucky, 

both these coal horizons occur in poorly exposed 

shale sequences and are only tentatively identified as 

thin discontinuous coal or underclay zones. As a result, the base of the Conemaugh is commonly proj ected from other stratigraphic horizons or is placed 

at the base of persistent and conspicuous red and 

variegated shale. 

The Conemaugh ~and Monongahela Formations 

crop out in an area of a:bout 1,000 km2 in northeastern Kentucky ·and have a combined thickness of 

more than 175 m; the thickness of the Conemaugh 

is estimated to be about 110m. They are mainly siltstone and shale and contain various amoun~ of 

subgraywacke, limestone, and ·co,al. The siltStone 

and shale are various shades of red, green, and gray; 

they are co.mmonly calcareous and .many contain 

thin beds ·and concretions of marine limestone. Black 

shale in the upper part of .the Conemaugh locally 

contains conchostracans-brackish- or fresh-water 

bivalved ·crustaceans (Connor and Flores, 1978). 

Subgraywacke occurs locally in ·channel deposits as 

much as 30 m thick that are ·commonly conglomeratic at their base. Marine limestone contain 

brachiopods, crinoids, gastropods, and fusulinids. 

Only a few coal beds occur •in the lower part of the 

Conemaugh, and these are thin and discontinuous. 

Regional studies ~suggest that rocks of Conemaugh 

and Monongahela age were deposited by northwestflowing streams (Wanless, 1975a, p. 49--53; Arkle, 

1974, p. 28). Shallow fresh-water lakes formed 

locally on the delta ·plain particularly during Monongahela deposition, and deltaic deposits were repeatedly inundated by eastward-trans·gress•ing seas, 

particularly during Conemaugh time. 

Red and green shale, characteristic of the Conemaugh, first occurs in the upper 50 rn of the Breathitt Formation, where greenish-gray shale is interbedded with the usual dark-gray shale of the 

Breathitt, in what is perceived as a "greening" of the 

shales; reddish-gray shale first appears in the upper 

25 m. These changes of color are thought to be 

related to a reduction in the amount of organic 

matter in the sediments and may represent a 

gradual shift toward less extensive swamps in contiguous areas and perhaps toward arid conditions 

in the source area. 

PENNSYLVANIAN STRATA OF WESTERN 

KENTUCKY 

The Pennsylvanian strata of the western Kentucky coal field occupy about 12,000 km2 of the 

southeastern part of the Eastern Interior basin, and 

are about 1,200 m thick. Like the Pennsylvanian 

rocks in eastern Kentucky, they are largely deltaic 

in origin and contain many coal beds. However, marine limestone makes .up a larger part of the section 

in western Kentucky than in eastern Kentucky. 

GEOLOGIC SETTING 

The Pennsylvanian rocks of western Kentucky unconformably overlie strata of Mississippian age. ·The 

southwestward paleoslope established ~n Mississippian time and s~hown by the sub-Pennsylvanian 

channel systems (fig. 7) ·probably was maintained 

throughout most of Pennsylvanian time (Potter, 

1963). The oldest Pennsylvanian strata deposited in 

these channels are pebbly orthoquartzites, assigned 

to upper Morrow age by Wanles·s (1975b, p. 74). 

Pennsylvanian strata . in the Eastern Interior 

basin thicken toward a depocenter in southeastern 

Illinois (McKee and Crosby, 1975, pl. 11). In wes·t-
KENTUCKY F21 

ern Kentucky, the interval between the No. 9 coal 

bed of Pennsylvanian age and the Vienna Limestone 

of Mi-ssissippian age ·ranges only from about 370 to 

460 m and suggests that subsidence was nearly uniform over the area during Early and Middle Pennsylvanian time. Some eastward thinning of strata 

in western Kentucky (fig. 10) might suggest the 

influence of the Cincinnati arch during Pennsylvanian time. 

The effect of the Cincinnati arch on Pennsylvanian 

deposition has long been a matter of speculation 

(Ashley, 1907; Miller, 1910). Detailed correlations 

between the Appalachian and Eastern Interior 

basins have been hampered by the lack of key beds 

common to both. basins and by the great variability 

of thickness (particularly in eastern Kentucky) and 

lithology of the Pennsylvanian sediments. Correlations, such as those shown in figure 10, have been 

based upon sparse paleontological evidence. Regional 

studies by Potter and Siever (1956a, b) and Siever 

and Potter (1956) of the petrology, crossbedding 

directions, . and sources of the basal Pennsylvanian 

sediments in the Eastern Interior basin indicate that 

the Cincinnat~ arch was not a major barrier to southwest transport of sediment derived mainly from 

source areas in the middle and northern Appalachians and the southeastern Canadian Shield. 

Fusulinids of Early Permian age from drill core 

samples in the Bordley quadrangle (R. C. Douglass, 

written commun., 1977) occur in the uppermost part 

of the section in a conformable sequence of shale and 

limestone (fig. 10). 

Cretaceous rocks are present to within 24 km of 

the western margin of the coal field and may have 

overlapped Pennsylvanian strata; however, they 

have not been recognized in the coal field. Pleistocene 

lake beds and outwash cover much of the low-lying 

areas along stream valleys adjacent to the Ohio 

River; in the same area, thick deposits of loess 

blanket hills (Ray, 1965; Shaw, 1915, Frye and 

others, 1972). These preglacial Pleistocene deposits 

and locally as much as 60 m thick in the valleys of 

the Ohio and Tradewater Rivers. · 

STRATIGRAPHY 

The Pennsylvanian strata of western Kentucky 

are divided into four formations, in ascending order, 

the Caseyville, Tradewater, Carbondale, and Sturgis 

Formations (fig. 14). Formations above the Caseyville are not lithostratigraphic units, and their 

boundaries are commonly placed at regionally persistent coal beds. The Caseyville Formation, like the 

Lee Formation of eastern Kentucky, is characterWESTERN KENTUCKY COAL FIELD 

I>Nen (1856-07a, b) This Report 

z ~ Member, ~ g 

ti; ffi ~ bed, 

~ (i) f2 and zone 

~ :::!: 

~ 

P= ~~--~ """""' limestone { ~ zone 

= 

Iii 

~ ~ > ~ 

r- Geiger lake f-- coal 

.m I'~ If a 

(i) 

II!. 

~· 

;:, c: 

·~ 

lisman coal ~ 

6 

.Ia 

r---' :::!: No. 18 coal I--

No. 18 coal!--

---- P= Carthage limestone p:::!:c; ~ Carthage limestone Membe; ,0 No. 17 coal,/ ~ 

No. 17 coal/ I-- :::,....-----

No. 16 coal No. 16coal 

No. 15 coal f--

~ No. 15 coal zone I--

No. 14 coal r--

~ z t-t- Madisonville 

Member 

limestone ~ 

No. 13 coal f-- <t No. 14 coal f--

~ z No. 13 coa~........_ Anvil Rock Sandstone ~ <t ji[ > Provilence limestone No. 12 coal r-- _. 1-

No. Member ,,/ 11 coal >- 1---- (i) No. 11 (Herrin) coal

1

/ I-- No. 10 coal c: z .!ll 

No:9 coal I-- -z !B "' No. 10 (Briar Hill) Coal coa,:/ ~ 

No. 8 coal 1-- w 

~~ No.9 coal 

No.7 --0.. No. 8b coal I-- coal 1-- !B~ No.8 coal 1-- .me~ 

No.6 coal 1-- -- ~ No. 7 coal ·~ 1--

No.5 coal ~ - - No.6 (Davis) coal ~ 

II!. 

Curlew Sandstone ~ "' No.4 coat of No. 4 coal =a p::c:i 

~ :'!il 

Curlew Limestone Owen (18571.;, . :::!:1-

No. 3 coal f--

Curlew Limestone Member ~ I No.4 coal/ 

No. 2 "'' >-----~ Lead Creek (Dunbar) limestone !== 

16~ Membebunbar coal/ 

r--

s No.lb«•l-~ 9,_ 

No.3 coal 1-- "' I!! "' <t 

H ~ ~ • i(''"'"""' :ll coal _ ~ No.2 coal 1--

l~M~ \ -I-'-- No. 1 b (Bell) coal r--

c: Battel)' Rock .!ll li; (Main Nolin) t--

ll coal 

a?.e; ~ 1:::!: 

FIGURE 14.-Diagram comparing n~menclature of Owen 

( 1856, 1857a, b) with that of this report. 
F22 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

ized by pebbly orthoquartzite; some of the basal 

sandstone is more than 75 m thick. However, the 

Caseyville, locally more than 200 m thick, is in · 

places dominantly shale and siltstone. The top of 

the formation is arbitrarily placed at the base of the 

No. 1b (Bell) coal bed where present, or is placed 

at the top of a persistent sandstone; in many places 

the Caseyville cannot be differentiated from the 

overlying Tradewater Formation. Subgraywacke is 

dominant above the Caseyville, although Siever 

(1957) reported a transitional zone between orthoquartzite and subgraywacke in the lower part of the 

Tradewater Formation. Because of poor exposure, 

much of the stratigraphy of the Pennsylvanian of 

western Kentucky is known primarily from subsurface data. 

The Pennsylvanian rocks consist of carbonaceous 

siltstone and clay shale, generally medium- to finegrained sandstone, marine limestone containing 

brachiopods, pelecypods, cephalopods, gastropods, 

crinoids, bryozoans, corals, and fusulinids in beds 

from less than 2 to more than 9 m thick ; and argillaceo'us and concretionary nonfossiliferous limestone. Sandstone and siltstone constitute about 55 

to 80 percent of the Pennsylvanian section, and silty 

shale and clay shale, generally associated with coal 

and limestone beds, make up about 20 to 45 percent. 

Limestone beds, although they make up only 

about 5 percent of the section, are an important tool 

for coal exploration and stratigraphic analysis. More 

than 35 marine transgressions have been· recorded 

in the Pennsylvanian section of the Eastern Interior 

basin (Wanless, 1975b, p. 72). In western Kentucky, 

four limestone horizons are recognized as being 

regionally persistent: the Curlew Limestone Member of the Tradewater Formation, and the Providence, Madisonville, and Carthage Limestone Members of the Sturgis Formation. The Lead Creek or 

Dunbar Limestone Member of the Tradewater Formation is found only in the eastern part of the coal 

field. 

About 24 principal coal beds or coal zones have 

been identified in western Kentucky. Most of these 

are shown in figure 14. The most persistent and 

thickest coal beds occur in the upper Tradewater 

Formation, the Carbondale Formation, and the lower 

Sturgis Formation. These include the Dunbar and 

Nos. 4, 6, 7., 9, 11, 12, 13, and 14 coal beds. 

The No. 11 coal bed contains a distinctive clay 

shale parting that can be traced throughout the 

Eastern Interior basin, making the coal bed the 

most useful marker in the western Kentucky coal 

field. This parting, 5 to 10 em thick, generally is 

light bluish gray, and is referred to as the "blue 

band." It has a pelletal or grainy structure similar 

to some flint clays but is composed of illite, chlorite, 

and kaolinite (Woltman, 1956). 

The Pennsylvanian rocks of western Kentucky and 

the Eastern Interior basin were deposited in alternately deltaic and shallow marine environments resulting in repeated sequences of strata that have 

been attributed to diastrophic changes (Weller, 

1956) or to eustatic sea level and climatic changes 

(Wanless and Shepard, 1936). These deposits probably resulted from a normal depositional pattern in 

a slowly subsiding bas:in that had a continuous 

source of terrigenous sediments (Wanfess and 

others, 1970). Interpretations of Pennsylvanian 

deposition in the Eastern Interior basin indicate that 

it was dominated by many prograding and shifting 

delta lobes of the Michigan River system (Pryor 

and Sable, 1974). 

BIOSTRATIGRAPHY OF THE PENNSYLVANIAN 

OF KENTUCKY 

Pennsylvanian System boundaries are all poorly 

defined in Kentucky, and their position as shown in 

the column (figs. 13 and 14) should be considered 

approximate. Most Pennsylvanian flora and fauna 

in Kentucky consist of relatively long-ranging forms 

of little value for detailed stratigraphic work. Most 

have not been systematically studied. The earliest 

investigations of fos:sil flora in Kentucky by Lesquereux (1857, 1861) were in part summarized by 

N6e (1923). Read and Mamay (1964) divided the 

Upper Paleozoic into 15 floral zones and assigned 9 

of these, zones 4 through 12, to the Pennsylvanian. 

All the Pennsylvanian zones occur in eastern Kentucky. They have also assigned the strata in western 

Kentucky to floral zones 6 through 12; however, 

they reported that plant fossils transitional to zones 

4 and 5 occur in basal Pennsylvanian strata in Indiana. None of the zonal boundaries of Read and 

Mamay correspond to lithostratigraphic horizons in 

Kentucky. 

Kosanke (1965a, b, 1966, 1967, 1968, 1969, 1971, 

1972) studied the spore assemblages of eastern Kentucky Pennsylvanian coals, but he indicated that the 

range zones of only a few taxa are useful for even 

the most general regional and interregional correlations. In detailed studies of coals in part of northeastern Kentucky, Kosanke (1973) suggested that 

the Princess 5B coal bed occurs at about the same 

stratigraphic :ttosition as the Davis or No. 6 coal bed 

of western Kentucky. (See fig. 10). He also corre-
KENTUCKY F23 

lated the Princess No. 7 coal bed with the Briar Hill 

or No. 10 ·.coal bed of western Kentucky. These 

analyses refer only to the youngest coals in the 

Pennsylvanian section of eastern Kentucky; regional 

and interregional coal correlations for most of the 

Breathitt and Lee Formations still depend mainly 

upon interpretations of physical stratigraphy. 

Coal-ball material has been described by Schopf 

(1961) from the Hamlin coal zone in eastern Kentucky and has been reported from the No. 11 coal 

of western Kentucky from a locality about 3.5 km 

northwest of Providence. (See fig. 15.) The latter 

contains a lycopsid-dominated assemblage that includes .stems of the following genera: Lepidocarpon, 

Co1~daite, Sphenophylltt-m, Sigillaria, and M edullosa 

(J. M. Schopf, 1963, written commun.). 

Pennsylvanian fauna of Kentucky have not been 

studied in detail. Morse (1931) cataloged and listed 

most of the major Pennsylvanian marine horizons in 

eastern Kentucky. Furnish and Knapp (1966) and 

Strimple and Knapp (1966) studied ammonoids and 

crinoids of upper Morrowan age from the Kendrick 

Shale of Jillson (1919) in detail, but only limited 

studies of megafauna (Cox, 1857) and microfauna 

(Thompson and Shaver, 1964) of western Kentucky 

have been published. 

Wanless (1975a and b) made extensive use of 

fusulinid zones for regional and interregional correlations of the Pennsylvanian of the Appalachian 

and Eastern Interior basins. These fossils locally are 

abundant in many of the marine limestones of western Kentucky but have not been carefully studied. 

A fusulinid that has "intermediate" attributes between Pro fusulinella and Fusulinella has been identified in the Lost Creek Lim.estone of Morse (1931) 

in southeastern Kentucky (Ping, 1978) ; no specific 

equivalent has been found in western Kentucky, but 

taxonomically it falls between the forms in the Lead 

Creek Limestone and the Curlew Limestone Members of the Tradewater Formation (R. C. Douglass, 

1978, written commun.). Wanless (1975b, p. 81) indirectly correlated the Curlew Limestone of the 

Tradewater Formation of western Kentucky with 

the Magoffin Member of the Breathitt Formation of 

eastern Kentucky on the basis of occurrences of 

Fusuh"'nella iowensis .in the Curlew and in Mercer 

Limestone Me·m·bers of the Pottsville Formation in 

Ohio. However, the Magoffin apparently occurs well 

below the Fusulinella zone and therefore below the 

Curlew Limestone. Limestone equivalent to the Mercer o.f Ohio has not yet been identified .in Kentucky, 

but fusulinids do occur in the Vanport Limestone as · 

used by Phalen (1912) and in the Brush Creek 

Limestone and Ames. Limestone Members of the 

Conemaugh Formation in northeastern Kentucky. 

The Brush Creek contains Triticites ohioensis ; a 

related species, Kansanella sp. aff. K. Tennis, is reported from the Carthage Limestone Member of the 

Sturgis Formation of western Kentucky (R. C. 

Douglass, 1978, written rommun.) . 

POST-CARBONIFEROUS TECTONIC EVENTS 

After depos.ition of the Pennsylvanian rocks, the 

southeastern part of the Appalachian basin was 

warped upward to form the broad eastern Kentucky 

syncline (fig. 15) ; this event was probably associated with a northwestward movement of about 12 

km of the Cumberland overthrust block. 

Two major fault systems, the Irvine-Paint Creek 

and the Kentucky River fault systems, cross the 

northern part of the Cumberland Plateau and extend 

into central Kentucky. They show a maximum vertical displacement of Pennsylvanian rocks of about 

75 m; the down-dropped block is to the south. 

The Moorman syncline in western Kentucky appears to have been a subsidiary depocenter of the 

Eastern Interior basin in Pennsylvanian time. In 

late Paleozoic or early Mesozoic time, movement in 

the Rough Creek and Pennyrile fault systems resulted ·in further downwarping of the syncline and 

in making it a distinct structural basin. 

The Rough Creek fault system is about 5 to 8 km 

wide and extends westward from central Kentucky 

through the central part of the western Kentucky 

coal field. It consists of many normal and thrust ( ?) 

faults which form a series of grabens and horsts. 

Vertical displacement along the system is as great 

as 900 m. 

The Kentucky River, Irvine-Paint Creek, and 

Rough Creek fault systems are part of the 38th 

parallel lineament, a west-trending alinement of 

structural features extending from northeastern 

Virginia to south-central Missouri. Post-Pennsylvanian movement appears to have been· mainly vertical, 

although en echelon faulting of short (8 km), northeast-oriented, normal faults occurs north and south 

of the Rough Creek system and may represent 

strike-slip movement. Regional Bouguer gravity 

I 

anomaly patterns in eastern and central Kentucky 

. suggest a right-lateral offset of about 80 km in the 

Precambrian basement (Heyl, 1972). Peridotite intrusions and fluorite mineralization in western Kentucky and kimberlite dikes in northeastern Kentucky 

may be related to this deep-seated zone of weakness. 

Radiogenic age dating of biotite from peridotite and 
F24 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

EXPLANATION 

Fault 

Thrust Fault 

Sawteeth on upper plate 

Antidine 

Syncline 

0 50 100 MilES I· •, ,• I·,. I I I 

0 50 100 KilOMETERS 

FIGURE 15.-Generalized structure map of Kentucky. 

kimberlite intrusions indicates emplacement in 

Early Permian time (Zartman and others, 1967). 

The City of Middlesboro is in a crater-like structure about 5.5 km in diameter in which the Pennsylvanian rocks are intensely deformed and locally 

brecciated. Englund and Roen (1962) noted shatter 

cones in sandstones in the center of the basin and 

interpreted the feature to be a meteorite-impact 

crater. 

ECONOMIC GEOLOGY 

Coal is the principal mineral resource of the Carboniferous in Kentucky. Beds of Pennsylvanian age 

have yielded more than 4.06 X 109 metric tons since 

commercial production began in about 1790 (Currens and Smith, 1977). Figure 16 shows the distribution of production between the eastern and western 

coal fields and the important contribution of S-llrface 

mining in the last three decades. Much of eastern 

Kentucky production has come from coal beds in 

the Elkhorn coal zone ; most western Kentucky production has come from the Nos. 9 and 11 coal beds. 

The coal is high-volatile A and B bituminous; the 

eastern Kentucky coal is of higher rank and generally lower in ash and sulfur content than the wes.tern Kentucky coal. Most coal is produced for utility 

or steam coal, but many coals of eastern Kentucky 

are used in the production of high-quality metallurgical coke. Estimates of original reserves in beds 

thicker than 35 em for eastern Kentucky .are 

30.33X 109 metric tons and for western Kentucky, 

35.27 x 109 metric tons (Huddle and others, 1963). 

Garboniferious strata are also a major source of 

oil, natural gas, and industrial and metallic minerals 

in Kentucky (figs. 17 and 18) . An estimated 60 

to 80 percent of the State's oil production and an 

estimated 50 to 70 percent of its natural gas production have come from Carboniferous rocks. Kentucky's cumulative -production of oil from 1883, the 

first year in which ·production records were kept 

(Crawford, 1958), through 1976 is 86.4X106 metric 

tons. Cumulative natural-gas production is estimated to be 92.6 x 109 m3 • Mississippian units in 

western Kentucky have been the principal source of 

Carboniferous oil, and Mississ•ippian rocks in eastern Kentucky have been the principal source of Carboniferous natural gas. Of the 1 X 106 metric tons o.f 

oil produced in Kentucky in 1976, about 70 percent 

came from Mississippian sandstone and limestone 

and about 5 percent came from Penm:;ylvanian sand-

-stone. Of the 1.8 x 109 m3 of natural gas produced 

during 1976, about 55 percent was from Mississippian sandstone and limestone and about 5 percent 

from Pennsylvanian sandstone. 

Missis·sippian limestone is the principal source of 

crushed stone for construction and agricultural ·use 

in wes.tern, south-central, and eastern Kentucky; 

most of the quarries and underground mines producing stone from Mississipp•ian rocks operate 
KENTUCKY F25 

Cl) 

z 

c 

.... 

(..) 

~ 20 

:E 

WESTERN COAL FIELD 

~ f, 

Underground I \ 

. production -........a J \ I 

/" .. •1\ I \ I ,. I 1 \f \~\.,. I 

,.,.. '\,. 

/'.I _,~ 

_ _., 

0~--~--~--~~~~L---~--L---L---J 

1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 

YEARS 

...,_,,, 

EASTERN 'cOAL FIELD 

,, 

~ 

'' "a ' ,,, 

Underground 

1

., \J ~ \\ 

production"/\ ,.. I 

I \ I \ 

/./ 

( 

I 

J 

I 

I 

I 

I 

I 

I 

) 

I ' I ' I I I \ !\ 

I ' ' \ II n I I 'I' l \ I 

J I Ill f \ I 

: \1' ~/ I I I 

I v 

I 

,J 

1910 1920 1930 1940 1950 1960 

YEARS 

1970 1980 

FIGURE 16.-Coal production of the eastern and western coal fields of Kentucky from 1890 to 1975 showing surface and 

underground mining. Auger production included in surface production. Surface production not significant and not 

separately reported prior to 1920. Modified from Currens and Smith (1977). 

partly or entirely in the Ste. Genevieve Lime·stone. 

Small quantities of limestone have also ·been obtained from thin beds of Pennsylv·anian age. Highcalcium limestones, mainly oolitic I.imestones of the 

Ste. Genevieve Limestone, Hirkin Formation, and 

Newman Limestone (Mississippian), are used for 

cem·ent, fluxstone, rook dust for underground coal 

mines, and formerly for lime. Oolitic limestones of 

the Girkin and, to a lesser extent, the Ste. Genevieve have been quarried for building stone in southcentral Kentucky. Pennsylvanian sandstone is 

crushed for construction aggregate. Road-surfacing 

material has been produced from rock asphalt deposits in sandstone of the Caseyville Formation 

(Pennsylvanian) and Big ·Clifty Sandstone Member 

of the Golconda Form·ation (Mississippian) in westcentral Kentucky. Deposits of high-silica sandstone 

of both Mississippian and Pennsylvanian ages have 

been sources of glass, molding, and foundry sands, 

sandstone of the Caseyville is ·being used in the 

manufacture of ferrosilicon. Dimenson stone has 

been produced from Mississ.ippia:n siltstone and 

sandstone and Pennsylvanian sandstone. 

Mississippian shale and Pennsy.lvanian shale and -

underclay are used for the production of structural 

clay products, mainly brick and tile, and, at one 

site, for lightweight aggregate. In northeastern 

Kentucky, a major fire-brick industry was based ori 

deposits of refractory clay in the Breathitt Formation (Pennsylvanian) , the main source being the 

Olive Hill Clay Bed of Crider (1913) .in the basal 

part of the Breathitt. 

Fluorspar has been yp.ined from depo~ts in Mississippian rocks of the western Kentucky fluorspar 

district, about 25 km. northeast o.f Paducah. Sphalerite (locally the principal mine product) , galena, 

barite, cadmium, germanium, and silver have been 

recovered as byp·roducts of fluorspar mining. The ore 

bodies occur as vein deposits along faults and, to a 

lesser extent, as 'bedding-replacement deposits 

(Tr·ace, 1974). 
F26 

z 

~ 

z 

fJ) 

~ z 

z 

~ 

z· 

<{ 

Q. 

Q. 

en 

fJ) 

fJ) 

fJ) 

THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

WESTERN 

STURGIS 

FORMATION 

GROVE CHURCH 

SHALE 

KINKAID 

LIMESTONE 

DEGONIA 

SANDSTONE 

CARBONDALE 

FORMATION 

TRADEWATER 

FORMATION 

CASEYVILLE 

FORMATION 

WEST-CENTRAL 

AND 

SOUTH-CENTRAL 

BUFFALO 

CLORE 

LIMESTONE 9 ~ 1-----~P-A....;;L~ES-T~I~NE;:__ ___ -1 ~ ~ WALLOW 

SANDSTONE 0 ~ 1------=--:-M=E~N:'-:-A:-=:=R"""D.:..=....----i ~ ~ FORMATION 

LIMESTONE ....1 u. 

WALTERSBURG 

SANDSTONE 

VIENNA 

LIMESTONE 

TAR SPRINGS TAR SPRINGS 

SANDSTONE SANDSTONE 

GLEN DEAN GLEN DEAN 

LIMESTONE LIMESTONE 

HARDINGSBURG HARDINSBURG 

SANDSTONE SANDSTONE 

HANEY HANEY 

~ ~ 1----=:;LI:.:.:M;.;:E~S_:..TO;::-;N;.;,;E~M:O:=E:.:.:M..:.:B:..::E:.:.:R_-l ~ ~ t--........:::LI:.:.:M.:..::E~ST,.;.,O;.;N...;.;E:;...,;,;,M;;;;E:;.:.M.:..::B:.::E.:..:.R_--l 8 ~ BIG CLIFTY 8 BIG CLIFTY 

....1 a: SANDSTONE MEMBER ....1 r-+--SA_N_,D=S=T=O.,_,N....,E=M=EM~BE_R_-1 

g !! BEECH CREEK g I BEECH CREEK 

LIMESTONE MEMBER 1--~LI::.::M.:::E:.::::S.:.:TO~N~E:....:.:M.:.::E:!!M.:.::B~E!.!R_~ 

CYPRESS ELWREN 

SANDSTONE SANDSTONE 

PAINT CREEK 

LIMESTONE 

(SHALE) 

BETHEL 

SANDSTONE 

RENAULT 

LIMESTONE 

·STE. GENEVIEVE 

LIMESTONE 

ST. LOUIS 

LIMESTONE 

SALEM 

LIMESTONE 

WARSAW 

LIMESTONE 

FORT PAYNE 

FORMATION 

REELSVILLE 

z 1-----=L.;.:.;IM..:.:E;..::S..:..T.=.O.:..:.N=-E __ __. 

z Q SAMPLE 

S2 ~· . SANDSTONE e: ~ !----~=~~------~ 

~ a: BEAVER BEND 

~ 1-----=L!!.:IM~E:!::S~TO=NE::....... __ ~ 

MOORETOWN 

FORMATION 

PAOLI 

LIMESTONE 

STE. GENEVIEVE 

LIMESTONE 

ST. LOUIS 

LIMESTONE 

SALEM 

LIMESTONE 

HARRODSBURG 

LIMESTONE 

~BORDEN BORDEN 

FORMATION 

~. FORMATION 

FUELS 

• 

• * . * 

. * 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

. * 

. * 

STONE 

~c L 

L 

~c 

A~C,D 

sA·R,S 

~c L 

L~c 

~D,S 

s 

L~c 

s~R;s 

L~c 

L~c.D,s 

L~C,D 

S~C,S 

L~C,S 

L~C,D,S 

~c 

L 

L~c 

L~c 

~c ~·D L S 

CLAY 

AND 

SHALE 

,XS,L 

MINERAL 

DEPOSITS 

AND 

IRON ORE 

~I 

~I 

~I 

~I 

~I 

FIGURE 17 .-Sources of oil, natural gas, and industrial arid metallic minerals in Carboniferous rocks of western Kentucky. Stratigraphic range of principal mineral deposits from Amos (1974) and Trace (1974). For explanation see 

figure 18. 
KENTUCKY 

~ EAST-CENTRAL, w EASTERN .... SOUTH-CENTRAL SOUTHEASTERN (/) AND >- (/) NORTHEASTERN 

MONONGAHELA 

FORMATION 

z CONEMAUGH 

~ FORMATION z 

~ BREATHITT 

~ BREATHITI FORMATION (/) FORMATION BREATHITT z LEE GROUP z 

w LEE FORMATION Q., FORMATION 

BREATHITI BREATHITI LEE 

FORMATION FORMATION FORMATION 

PENNINGTON 

PENNINGTON FORMATION PENNINGTON 

FORMATION CARTER ) 

FORMATION 

CAVE SS. 

BANGOR 

LIMESTONE 

HARTSELLE 

FORMATION NEWMAN 

MONTEAGLE 

LIMESTONE NEWMAN 

z LIMESTONE LIMESTONE 

Q., 

~ ST. LOUIS D.; LIMESTONE r:;; 

(/) WARSAW-SALEM 

~ FORMATIONS ~ BORDEN FORT PAYNE 

~(BORDEN FORMATION CHERT 

ORMATION . GRAINGER 

FORMATION 

>- SUNBURY <( SUNBURY 

z SHALE (!) SHALE 

;a~ 0 

BEREA ow BEREA <t~ z<t 

SANDSTONE ~~ SANDSTONE 

~(/) BEDFORD <( BEDFORD z :I: SHALE u SHALE 

EXPLANATION 

FUELS 

• on * Natural gas 

L ~ Lbnestone 

~C Construction 

L stone, 

agricultural 

Umestone 

L ~D Dimension stone 

s 

L ~ Special uses: 

cement, flux. 

rock dust, 

lbne 

STONE 

S ~ Sandstone 

5 

"X;C Construction 

aggregate 

D 

S ~ Dimension stone 

s ~R Rock asphalt 

s 

S ~ Special uses; 

glass, moulding, 

and foundary 

sands; 

ferrosdicon 

FUELS STONE 

L 

~c 

• "* s 

~D,S 

• "* S~C,D 

S~C,S 

• * 

s 

~s 

~c L 

• * L~c.s 

L 

~c 

L~c 

L~c 

• * ~D ~c s 1.: 

• * 

ClAY 

AND 

SHALE 

XS Structural 

s 

~D 

day products 

X R Refactory 

L day 

X Lightweight 

aggregate 

CLAY 

AND 

SHALE 

XS,R 

XS,R 

xs 

MINERAL 

DEPOSITS AND 

IRON ORE 

~I 

Auorspar 

Sphalerite 

Galena 

Barite 

Iron Ore 

F27 

IRON 

ORE 

~I 

~I 

~I 

~I 

~I 

FIGURE 18.-Sources of oil, natural gas, and industrial and metallic minerals in Carboniferous rocks of eastern Kentucky. 
F28 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Limonitic and sideritic iron ores in Carboniferous 

rocks were mined extensively during the 19th century for .smelting in local furnaces. Deposits in the 

Breathitt and Conemaugh Formations (Pennsylvanian) and at the top of the N ewm·an Li·mestone 

(Mississippian) were ·sources o.f ore for furnaces ·in 

northeastern and east-central Kentucky. Furnaces 

were built at several :locations in west-central and 

western Kentucky to utilize ore from deposits in 

Missi·ssippian and Pennsylvanian units. 

Subsurface deposits o.f gypsum and anhydrite in 

the lower St. Louis Limestone (Mississippian) of 

west-central Ken:bucky may be a potential resource 

(McGrain and Helton, 1964). 

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192 p. 

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KENTUCKY F29 

Eagar, R. M. C., 1973, Variation in shape of shell in relation 

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Englund, K. J., 1964, Stratigraphy of the Lee Formation in 

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F30 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

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KENTUCKY F31 

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America Spec. Paper 148, p. 187-208. 
F32 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

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The Virginias, v. 6, p. 7-16. 

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of the No. 6 coal of Illinois: Illinois State Acad. Sci. 

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1967, K-Ar and Rb-Sr ages of some alkalic intrusive 

rocks from central and eastern United States: Am. Jour. 

Sci., v. 265, no. 10, p. 848-870. 
The Mississippian and Pennsylvanian 

(Carboniferous) Systems in the 

United States-Tennessee 

By ROBERT C. MILICI, GARRETT BRIGGS, LARRY M. KNOX, 

PRESTON D. SITTERLY and ANTHONY T. STATLER 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1110-G 

Prepared in cooperation with the State of Tennessee 

Department of Conservation, Division of Geology 

Historical review and summary of areal, stratigraphic, 

structural, and economic geology of Mississippian and 

Pennsylvanian rocks in Tennessee 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1979 

FIGURE 1. 

2. 

3. 

4. 

6. 

6. 

7. 

8. 

9. 

to. 

11-16. 

CONTENTS 

Page 

Albstract ----------------------------------------------------------------- G1 

Introduction ------------------------------------------------------------- 1 

Alcknowledgments ---------------------------------------------------- 6 

Stratigraphy ------------------------------------------------------------- 6 

Chattanooga Shale --------------------------------------------------- 5 

Grainger Formation ___ ----------------------------------------------- 8 

Fort Payne Formation ------------------------------------------------ 10 

Newman Limestone and equivalents ------------------------------------ 12 

Chilhowee Mountain belt ------------------------------------------ 13 

Clinch Mountain belt --------------------------------------------- 13 

Newman Ridge and Pine Mountain block -------------------------- 14 

Carbonate platform deposits of the Cumberland Plateau and Highland 

Rim ------------------------------------------------------- 14 

VVarsaw Limestone ------------------------------------------- 15 

St. Louis Limestone ------------------------------------------ 16 

Monteagle and Ste. Genevieve Limestones ---------------------- 17 

Hartselle Formation ------------------------------------------ 17 Bangor Limestone _ _ _ _ _ _ _ __ _ _ __ _ _ _ _ __ _ _ __ __ _ _ ____ __ __ _ _ ____ _ _ _ 17 

Pennington Formation _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ __ _ __ ___ _ _ __ __ __ __ _ _ _ ___ _ 18 

The coal measures ---------------------------------------------------- 18 

Gizzard Group ----------------------------------~---------------- 19 

Crab Orchard Mountains Group --------------------------------- 22 

Crooked Fork Group ---------------------------------------------- 24 

Delta-plain sequence -------------~-------------------------------- 24 

Indicators of depositional environments in the upper-delta-plain sequence ------ 28 

Siderite -------------------------------------------------------------- 30 

Fossil trees ---------------------------------------------------------- 31 

Heavy metals and sulfur ---------------------------------------------- 32 

Mississippian oil and gas fields in the northern Cumberland Plateau ---------- 34 

References cited ---------------------------------------------------------- 36 

ILLUSTRATIONS 

Map showing distribution of Carboniferous strata in Tennessee --------------------------------

Chart showing nomenclature of Mississippian strata in Tennessee ------------------------------

Chart showing nomenclature of Pennsylvanian strata in eastern Tennessee and adjacent parts of 

lCentucky -----------------------------------·------------------------------------------- Map showing locations of stratigraphic cross sections in eastern Tennessee --------------------

Map showing ages of pre-Chattanooga strata in Tennessee -----------------------------------

Isopach map of the Chattanooga Shale in eastern Tennessee ----------------------------------- Stratigraphic cross section along line Al-Al' ______ ---·-- ________________________________________ _ 

Stratigraphic cross section along line B-B' ____________________________ ----- _____________ ----- _ 

Generalized isopach map of the Grainger Formation in eastern Tennessee ----------------------

Map showing distribution of facies of the Fort Payne Formation in central Tennessee ----------

Stratigraphic c·ross section: 

11. Allong line B-C-D· -----------------------·-------------------------------------------

12. Allong line C-C' ---------------------------------------------------------------------

13. Allong line D-E'-F'-D' -------------------------------------------------------------

14. Allong line E-E' --------------------------------------------------------------------

15. Allong line F-F' ---------------------------------------------------------------------

III 

Page 

G2 

2 

3 

4 

5 

6 

8 

9 

9 

12 

15 

16 

19 

20 

21 
IV CONTENTS 

Page 

FIGURES 16-20: Map showing areas underlain by, and areas mined out of: 

16. The Sewanee and Richland coal seams in the southern Cumberland Plateau, Tennessee --- G23 

17. The Coal Creek coal bed in northern Tennessee --------------------------------------- 25 

18. The Jellico coal bed in northern Tennessee -------------------------------------------- 26 

19. The Big Mary coal bed in northern Tennessee --------------------------------------- 28 

20. The Pewee coal bed in northern Tennessee -------------------------------------------- 29 

21. Columnar section of upper Middle Pennsylvanian coal-bearing sequences, with drawings of strip mine 

high walls _______ -------- _ ------------ _____ --·---- ________________ ------ _________ ----- ___ 30 

22. Tree, showing generation of new roots at a higher sediment-water interface that formed when the 

base was buried by a flood deposit ------------------------------------------------------- 32 

23. Planar-convex sand bodies at the base of a fossil tree ---------------------------------------- 33 

24. Lepidodendron buried in growth position by shaly deposits to a depth of 4.6 m (15 ft) ---------- 34 

25. Map showing locations of Mississippian oil and gas pools in the northern Cumberland Plateau ____ 35 

TABLES 

Page 

TABLE 1. Representative analyses and rank of S·elected Tennessee coal beds (Luther, 1959; Johnson and Luther, 

1972) ---------------------------------------------------------------------------------------- G25 

2. List of selected Mississippian oil and gas pools, Tennessee ----------------------------------------- 36 
THE MISSISSIPPIAN AND PENNSYLVANIAN (CARBONIFEROUS) 

SYSTEMS IN THE UNITED STATES-TENNESSEE 

By RoBERT C. MILICI/ GARRETT BRIGGS/ LARRY M. KNox/ 

PRESTON D. SITTERLY/ and ANTHONY T. STATLER4 

ABSTRACT 

Carboniferous strata are distributed widely across Tennessee. In general, Mississppian deposits in eastern Tennessee are thick and are dominated by terrigenous clastic deposits in the Appalachian geosyncline; Mississippian deposits to the west are thin and are composed of limestone 

that was deposited on a carbonate platform. The ~eosyncline was filled, and the carbonate platform was ultmately 

overlapped by Upper Mississippian and Pennsylvanian terrigenous clastic deposits. 

Geosyncline sequences are present in several isolated areas 

on Valley and Ridge thrust blocks, whereas carbonate plat-· 

form deposits extend from the western Valley and Ridge, 

beneath the Cumberland Plateau, to the western Highland 

Rim. Stratigraphic nomenclature reflects regional changes in 

stratigraphic sequences from the geosyncline to the carbonate 

platform. The Carboniferous strata were deposited in marine 

littoral, and delta-plain environments. ' 

Tennessee produces petroleum from Mississippian strata 

primarily in the northern part of the Cumberland Plateau~ Pennsylvanian strata contain abundant coal beds, and five 

of these, the Sewanee, Coal Creek, Jellico, Big Mary, and 

Pewee, contain most of the reserves. 

INTRODUCTION 

Carboniferous strata underlie a great area of 

central and eastern Tennessee, extending westward 

from limited exposures on fault blocks in the Valley 

and Ridge across. the Cumberland Plateau to the 

broad plateau of the Highland Rim (fig. 1). The 

lower part of the Mississippian section is pres.erved 

on the Highland Rim, which forms a crude ellipse 

around Ordovician and Silurian strata of the 

Central Basin (Nashville structural dome) of Tennessee. The most completely preserved section of 

Carboniferous strata in the State is beneath the 

Cumberland Plateau, where the stratigraphy of the 

older beds is known both from their extensive ex1 Tennessee Department of Conservation, Division of Geology, Knoxville, 

Tenn. 87919. 

11 University of Tennessee, Knoxville, Tenn. 37916. 

a Sehorn and Kennedy, Knoxville, Tenn. 87902. 

'Tennessee Department of Conservation, Division of Geology, Nashville, 

Tenn. 87219. 

posure along the linear Sequatchie Valley and from 

the many oil tests drilled in the region. 

The lower part of the Carboniferous sequence in 

Tennessee is composed largely of carbonate rocks 

that were deposited on a relatively shallow stable 

platform to the west, and of terrigenous clastic and 

carbonate rocks that were deposited in a subsiding 

geosyncline to the east (fig. 2) . The upper part of 

the sequence consists almost entirely of coal-bearing 

terrigenous clastic deposits, representing either 

coastal barrier island-lagoon depositional environments or the depositional environments diagnostic 

of deltaic sedimentation (fig. 3). The carbonate sequence is separated from. the coal-bearing beds by 

a transitional unit, the Pennington Formation, a 

heterogeneous unit composed of many lithologies. In 

general, the lower carbonate rocks and the transitional Pennington Formation are Mississippian, 

whereas overlying terrigenous clastic rocks are 

Pennsylvanian. 

Structurally, the Cumberland Plateau lies in a 

broad elongated downwarp between the Nashville 

dome and the thrusts of the Valley and Ridge. The 

synclinori urn pi unges gently northeastward from a 

broad, low, west-trending cross structure, a ·branch 

of the Nashville dome, that extends along the southern boundary of Tennessee west of Chattanooga. 

The southeastern regional dip from the Nashville 

dome, combined with the gentle northeastern regional plunge induced by the Chattanooga. arch, accounts for the distribution of the coal-bearing strata 

of the plateau; only lowermost Pennsylvanian beds 

remain in the southern plateau, whereas younger 

beds are preserved in the Wart burg basin and on 

the Pine Mountain block to the northeast. 

Historically, the Tennessee coal field has been divided into northern (Glenn, 1925) and southern Nelson, 1925) coal fields. The boundary generally follows 

the routes of the old Tennessee Central Railway and 

Gl 
G2 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

/ 

_,. ___// EXPLANATION 

( r- J Mississippian 

~hldt:.antob2_·a L CJ Pennsylvanian 

Contact 

Fault 

0 50 100 MILES 

11

1

1 1

1 

I '1 

I I 

I 

0 50 100 KILOMETERS 

FIGURE !.-Distribution of Carboniferous strata in Tennessee (from King and Beikman, 1974). 

(/) WESTERN CUMBERLAND PINE MOUN1AIN BELT EAST OF CLINCH CHILHOWEE w HIGHLAND PLATEAU AND BLOCK (Englund, NEWMAN RIDGE MOUNTAIN MOUNTAIN a: 

w (Mixon and Harris, 1971) RIM EASTERN 1964, 1968) (Sanders, 1952, unpub. (Newman and Nelson, (/) 

HIGHLAND RIM data; Hasson, 1973) 1965) 

Gizzard Group 

(lower part) Pennington Foramtion Pennington Formation Pennington Formation 

z 

<( 

a: Pennington Formation w Cove Creek t- Formation (/) 

w 

:I: 

u Bangor Limestone Fido Sandstone 

Hartselle Sandstone CD 

c Fisher Creek 0 Limestone t:i 

Ste. Genevieve Newman Limestone Newman Limestone CD 

Limestone Monteagle Limestone E Gilliam Creek z ::i Limestone <( c 

u .., 

E Clifton Creek Limestone w ~ Snowflake Formation :::!!: St. Louis Limestone St. Louis Limestone 

<( z a: Laurel Branch Limestone w Pressmens Home :::!!: Greasy Cove Formation 

Warsaw Limestone Warsaw Limestone Formation 

Maccrady 

Formation 

z 

<( 

w 

(!) Fort Payne Grainger Fort Payne Formation Fort Payne Formation <( Chert Formation (/) 

0 

Grainger Formation Grainger Formation Grainger Formation 

~ 

z 

<( 

~ 

0 

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:I: Maury Shale Maury Shale Mau,Y Shale a: 

w ? ? ? 0 

z 

~ Chattanooga Shale Chattanooga Shale Chattanooga Shale 

(upper part) (upper part) (upper part) 

FIGURE 2.-N omenclature of Mississippian strata in Tennessee. 
(/) 

w Wilson and others a: 

w (1956) (/) 

>-

z Cross Mountain w 

:I: Formation 

(!) 

w 

...J 

...J 

<( 

1-Grassy Spring coal bed-

---1 1-- Rock Spring coal bed -

Vowell Mountain 

Formation 

- Pewee coal bed -

Readoak Mountain 

Formation 

1-- Windrock coal bed -

<( 

:I: 

~ Graves Gap Formation 

z 

~ 

r-- Jordan coal bed -

Indian Bluff Formation 

-Jellico coal bed -

Slatestone Formation 

TENNESSEE 

Englund (1964, 1968) 

Wanless (1946, pl. 32) 

Bryson Formation 

1- Red Spring coal bed ? -

Hignite Formation 

a. 1--- Sharp coal bed- ::J 

0 Catron Formation 5 

:t:: ~ Poplar Lick coal bed - :s 

(Q 

Q) 

m 

Mingo Formation 

\ 

1-- Harlan coal bed -

Hance Formation 

I 

I 

, 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

, 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

, 

I 

I 

I 

I 

, 

I 

I 

, 

I 

(/) 

w Slighty modified from a: Englund(1964, 1968)1 w Wilson and others ( 1956)1 (/) 

"'-Poplar Creek coal bed 

Wartburg Sandstone 

a. 

::J 

e a. (!) Hance Formation ::J Glenmary Shale :t:: e :s (!) (Q 

~ Q) 

0 Coalfield Sandstone m LL 

"0 

Q) 

~ 

0 Burnt Mill Shale .e 

u 

Crossville Sandstone 

Dorton Shale 

a: Roc~castle Conglomerate w 

> 

~ a. Lee Formation ::J 

~ e 

z (!) Vandever Formation (/) 

c: 

·a; 

E 

::J 

0 Newton Sandstone ~ 

'E 

(Q 

.r:. 

~ 

0 Whitwell Shale 

..c 

(Q 

u 

Sewanee Conglomerate 

? 

Signal Point Shale. Pennington Formation 

(upper member) 

a. 

::J 

e 

(!) Warren Point Sandstone Tongues of Lee 

'E Formation (Q 

... ?- ...._ ::::1 ? 

a a: 

w 

1- Raccoon Mountain Pennington Formation (/) 

w Formation (lower member) 

:I: 

u 

1Queried dguble lines show opinions concerning 

the Mississippian- Pennsylvanian boundary. 

G3 

FIGURE 3.-Nomenclature of Pennsylvanian strata in eastern Tennessee and adjacent parts of Kentucky. Only coal 

beds that separate formations are shown. 
Hh" KENTUCKY --- ------.7.-----~----~-

--~= ~~ L~,, A ~'(~~~~i~~~Pi~~ N ·'"1~;:~:::- z:-;r· '!I -...r--... . .. AE-~ 

,.....:..-\ J-· 

--~~_..,..--~~Hvfttll.,; ~._.. 

..__...,__ -.-"--\ D E K A L 

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EXPLANATION 

_,,, 

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. ?'"\,t;:::_~~;~;) Mississippian Pennsylvanian 

c.-"··-l 0 15 30 MILES I I I I I 

0 15 30 KILOMETERS 

.. -'~;eo£Jj:,_~:··- .. ;G:L_ __ FIGURE 4.-Location of stratigraphic cross sections in eastern Tennessee. 

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TENNESSEE G5 

the more recently constructed Interstate 40 between 

Harriman and Monterey. The southern Cumberland 

Plateau and the western part of the northern 

plateau consist of broad, moderately dissected uplands underlain by widespread thick orthoquartzites 

and interbedded shale units. In contrast, the higher 

mountains in the northeastern part of the Cumber~ 

land Plateau in Tennessee are underlain by units 

composed mostly of shale and siltstone and thinner 

sandstone beds; these sandstone beds are not nearly 

so widespread as the orthoquartzites and are generally subgraywackes. Carboniferous strata are exposed on the western half of the Pine Mountain 

thrust block; -this part of the block is in the plateau. 

Four major outcroppings of Carboniferous strata 

occur on the thrust bl.o.ck.s of the Valley and Ridge 

of Tennessee: on Whiteoak Mountain to the south, 

near Chilhowee Mountain along the toe of the Blue 

Ridge, and to the north near Clinch Mountain and 

on Newman Ridge. The outcrop along the Blue Ridge 

contains only the lower part of the Mississippian 

section ; a little Pennsylvanian is preserved at the 

top of the section along Whiteoak Mountain; and the 

Pennington Formation caps the Mississippian sections in the Clinch Mountain strike belt and on Newman Ridge. Regional stratigraphic cross sections 

along lines shown in figure 4 are presented herein 

to illustrate Devonian to Pennsylvanian thickness 

and facies variations in eastern Tennessee. 

The stratigraphic nomenclature used in this paper 

has not been reviewed by the Geologic Names Committee of the U.S. Geological Survey. The nomenclature used here conforms with the current usage 

of the Tennessee Department of Conservation, Division of Geology. 

ACKNOWLEDGMENTS 

The regional stratigraphic framework was compiled largely by Milici. Briggs .summarized research 

on delta-plain depositional environments performed 

at the Univer.sity of Tennesse·e under DOE (U.S. 

Department of Energy) · Research Contract No. 

E-(40-1)-4946. Knox assisted in preparing the 

regional stratigraphic cross sections and contributed 

the sections on the Coal Creek and Jellico coal beds. 

Sitterly oontributed the sections on the Pewee and 

Big Mary coal beds, and Statler described the petroleum resources of Carboniferous strata in Tennessee. A. R. Leamon assisted in preparing the coal 

maps. E. T. Luther reviewed the manuscript. 

STRATIGRAPHY 

The final major cycle of Paleozoic sedimentation 

in Tennessee began with the Middle to Late Devonian submergence of an erosional surface that cut 

across beds ranging in age from Middle Ordovician 

to Early Devonian. Then, mud, silt, and sand of the 

Chattanooga Shale were deposited on this surface. 

The Chattanooga Shale lies upon about 25 formati:ons in central and eastern Tennessee (fig. 5). Basal 

beds of the Chattanooga range generally from Middle to Late Devonian in age .With minor exceptions, 

the Devonian-Mississippian boundary-the base of 

the Carboniferous system-is either within or at the 

top of the Chattanooga Shale. On the basis of 

studies of conodonts, plant fossils, and bones, 

Conant and Swanson (1961, p. 21) described the 

Chattanooga as being entirely Devonian in central 

Tennessee. However, conodonts studied by Roen and 

others (1964) and fossils described by Glover 

(1959) show that the upper part of the Chattanooga 

is Mississippian in the Valley and Ridge near Big 

Stone Gap in southwestern Virginia and near Chilhowee Mountain in eastern Tennessee. 

CHATTANOOGA SHALE 

The Chattanooga ,Shale (Hayes, 1891), which is 

a potential source of uranium and hydrocarbons, 

50 MILES I 

FIGURE 5.-Ages of pre-Chattanooga strata in eastern Tennessee. 
G6 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

varies greatly in thickness in Tennessee. In places 

in central Tennessee, the formation is absent altogether (Conant and Swanson, 1961, pl. 1; Wiethe 

and Sitterly, 1978). Elsewhere in central Tennessee 

it ranges from 3 to 10m (10 to 33 ft) in thickness. 

The formation thickens greatly to the east and may 

be as much as 610 m (2,000 ft) thick in the Greendale syncline along Clinch Mountain (fig. 6). 

Chilhowee Mountain belt.-The Chattanooga 

Shale is about 7.6 m (25 ft) thick along the northwest flank of Chilhowee Mountain (Neuman and 

Nelson, 1965, p. D40-D41). There the formation 

consists of dark gray carbonaceous shale and has 

several centimeters of fine-grained sandstone at its 

base. In the Chilhowee Mountain strike belt, the 

Chattanooga overlies the Bays Formation (Middle 

Ordovician) unconformably, in some places resting 

on quartzites and in other places on bentonitic volcanic ash within the Bays (Glover, 1959, p. 145). 

Fossils collected by Neuman and Nelson (1965) 

and by Glover (1959) indicate that the Chattanooga 

along Chilhowee Mountain is of Late Devonion or 

Early Mississippian age. 

Clinch Mountain belt.-The Paleozoic stratig- · 

raphy of the Greendale syncline along Clinch Mountain was studied in detail by Sanders ( 1952) . The 

nomenclature of Devonian and Mississippian formations that was proposed by Sanders (1952) for 

that region has not been formally published but has 

been modified and adopted by the Tennessee Division of Geology for mapping· purposes and is used 

in this report. 

87" 86" 

The Chattanooga Shale crops out along the southeastern flank of Clinch Mountain. The formation 

thickens markedly from about 122 m ( 400 ft) at 

the southern end of the outcrop belt in Grainger 

County to about 610 m (2,000 ft) in Hawkins 

County, and from this area thins northeastward into 

Virginia. 

In the Greendale syncline strike belt, the Chattanooga rests on older Devonian beds that are commonly mapped with the Clinch Sandstone because 

they are so thin. Sanders (1952) recognized about 

1.8 m ( 6 ft) of coarse-grained fossiliferous sandstone, which he correlated with the Ridgely Sandstone (Lower Devonian) of the central Appalachians. On Clinch Mountain, the Ridgely (or Oriskany) 

is in places overlain by about 0.3 m (1 ft) of yellowish-gray chert, which Sanders (1952) correlated 

with the Huntersville Chert of West Virginia. 

Dennison and Boucot (1974) correlated the preChattanooga Lower Devonian sequence at Little War 

Gap on Clinch Mountain with the Wildcat Valley 

Sandstone of Miller, Harris, and Roen (1964) and 

divided it into a lower Oriskany Member (2.9 m, 9.4 

ft thick) and an upper Huntersville Member (2.4 

m, 7.9 ft thick), which is composed of fine-grained 

glauconitic and phosphatic sandstone. 

Sanders (1952) subdivided the Chattanooga Shale 

of the Greendale syncline into three units ( classified as members by the Tennessee Division of Geology), tHe Little War Gap Shale Member at the base, 

the Klepper School Member in the middle, and the 

Salt Lick Gap Shale Member at the top. Hasson 

I 

82" -1-7 

Johnson City 0 ( 

~~1/' 

50 MILES 

I 

50 KILOMETERS 

FIGURE 6.-Isopach map of the Chattanooga Shale in eastern Tennessee (in part from Conant and Swanson, 1961, pl. 15). 

Isopachs in meters. 
TENNESSEE G7 

(1972, 1973) and Dennison and Boucot (1974) 

placed the top of the Chattanooga Shale at a somewhat higher stratigraphic level than did Sanders 

(1952). 

A detailed section of the Little War Gap Shale 

Member was m.easured along Tennessee Highway 70 

near Little War Gap in Clinch Mountain by Dennison and Boucot (1974, p. 98-99). In this. section, 

the member is 287 m (940 ft) thick and generally 

consists of fissile black shale and subsidiary amounts 

of gray shale. 

The Klepper School Member consists generally of 

finely laminated dark-gray micaceous siltstone, darkgray laminated silty shale, and interlaminated lightgray and dark carbonaceous siltstone and shale. 

Southwest of its type section on Tennessee Highway 70, the Klepper School ·contains beds of very 

fine grained light-gray sandstone that range in 

thickness from 15 to 61 em. (0.5-2 ft). Sanders 

(1952) estimated the unit to be about 244 m. (800 

ft) thick at its type section, thinning to 152 m 

(500 ft) or less to the southwest. Dennison and 

Boucot (1974) measured 327.4 m (1,074 ft) for the 

Klepper School Member at its type section. 

Sanders (1952) mapped about 7.6 m (25 ft) of 

fissile black shale above the Klepper School Me·mber 

as the Salt Lick Gap Shale Member, but exposures 

are too poor to designate and measure a type section. Correlation of the upper part of the Chattanooga Shale, including the Salt Lick Gap Shale 

Member, in the Greendale syncline in Tennessee with 

strata near Big Stone Gap in southwestern Virginia 

is in question. Hasson (1972) placed as much as 

65.8 m (216ft) of the basal beds of Sanders' (1952) 

Grainger Formation in the Chattanooga Shale and 

correlated this unit with the Big Stone Gap Member of the Chattanooga Shale (Roen and others, 

1964). If Hasson (1972) is correct, then the Big 

Stone Gap, including the Salt Lick Gap Shale at 

its base, should be extended into Tennessee as the 

upper member of the Chattanooga Shale. 

Newman Ridge and Pine Mountain block.-The 

Chattanooga Shale thins progr~ssively to the northwest, and on Newman Ridge along the southeast 

side of Powell Mountain, it consists of about 122 m 

( 400 ft) of grayish-black carbonaceous shale (fig. 

7). The shale is commonly pyritic and contains I 

small amounts of interbedded greenish-gray shale 

(Harris and Mixon, 1970; Mixon and Harris, 1971; 

Harris and others, 1962) . On Newman Ridge, the 

Chattanooga overlies the Upper Silurian Hancock 

Dolomite (Sneedville Limestone of Hardeman and 

others, 1966). 

On rthe Pine Mountain block near Cumberland 

Gap, the Chattanooga is 61-91 m (200-300 ft) thick 

and consists mostly of grayish-black carbonaceous 

and pyritic shale that lies unconformably on the 

Hancock Dolomite (Englund, 1964; Harris, 1965). 

Englund (1964) ·considered the 15.2 m (50 ft) of 

greenish-gray shale that in places is at the base of 

the Chattanooga to be part of that formation. 

Central Tennessee.-Because of its potential as a 

low-grade uranium resource, the Chattanooga in 

central Tennessee and in nearby areas was extensively studied by the U.S. Geological Survey (Hass, 

1956; Glover, 1959; Conant and Swanson, 1961). 

The Chattanooga lies on formations· ranging in age 

from Middle Ordovician to Devonian in central 

Tennessee; the older beds are truncated ove·r the 

crest of the Nashville dome (Wilson, 1949, pl. 2; 

Conant and Swanson, 1961, pl. 3). In central Tennessee, the Chattanooga is divided into three members, a basal Hardin Sandstone Member, a middle 

Dowelltown Member, and an upper Gassa.way 

Member. 

The Hardin Sandstone Member is. generally present in several counties in central Tennessee, where 

it is as much as 4.9 m (16 ft) thick (Conant and 

Swanson, 1961, fig. 6). The me·mber consists of 

massive fine-grained gray sandstone containing 

minor amounts of phosphate and bones. The Hardin 

Sandstone Member was regarded by Conant and 

Swanson (1961, p. 28) as a local overthickening of a 

widespread but very thin basal Chattanooga sandsone or conglomerate. They preferred to restrict the 

use of the name Hardin to the area where the unit 

is thick, is of Devonian age, and is fine grained and 

massively bedded. The Hardin Sandstone Member is Upper Devonian, but elsewhere· the· age of 

the thin basal sandstone or conglomerate v·aries as 

the age of the overlying shale varies. and is, in different places, Late Devonian or possibly Mississippian (Conant and Swanson, 1961, p. 25). 

The Dowelltown Member overlies either the 

Hardin Sandstone Member or the much older beds 

beneath the Chattanooga and consists of a lower 

black shale unit and an upper unit composed of interbedded light-gray claystone and dark-gray shale 

beds. The member is present around the northern 

and central parts of the Highland Rim, where it is 

commonly 4.6-6.1 m (15-20 ft) thick, but it is not 

very thick near the southern border of Tennessee. 

The contact between the Dowelltown Member and 

overlying Gassaway Member was interpreted by 

Conant and Swanson (1961, p. 29) to be a dias.tem 

or slight unconformity within the Chattanooga. The 
G8 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

A 

c: o.!2 

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:~~~~~~~~~~~~~~~~~( Harlan coal bed 

Pathfork coal bed 

Clear Fork coal bed 

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FIGURE 7.-Stragraphic cross section along line A-A'. 

Gassaway Member is the most widespread of the 

three members of the Chattanooga Shale. Typkally 

the unit consists of massive black bituminous shale. 

In Tennessee, the member is generally 4.6-6.1 m 

(15-20 ft) thick but thins to the south, and along 

the southern Tennessee border, it is less· than 3 m 

(10ft) thick. 

GRAINGER FORMATION 

The Grainger Formation (Keith, 1895) overlies 

the Chattanooga Shale in the Chilhowee Mountain, 

Clinch Mountain, and Newman Ridge strike belts 

and in exposures on the Pine Mountain block. The 

formation grades to the west and south into the 

Fort Payne Formation and to the north and northwest into the Borden Formation (figs. 7, 8). The 

Grainger reaches a maximum thickness. of 320 m 

(1,050 ft) ; the thicker sections are near Chilhowee 

Mountain, and thinner ones are on the Pine Mountain block (fig. 9) . 

Chilhowee Mountain belt.-Neuman and Nelson 

(1965, p. D43) measured 320 m (1,050 ft) of 
B 

Limestones 

35" 

TENNESSEE 

RACCOON MOUNTAIN 

Sewanee Conglomerate 

~rf:-t'~tlt-r.. Signal Point Shale 

Fort Payne 

Formation 

Chana nooga Shale --

METERS FEET 

240 800 

0 

Gizzard Group 

Pennington Formation 

Bangor Limestone 

Hartselle Sandstone 

10 MILES 

10 15 KILOMETERS 

FIGURE B.-Stratigraphic cross section along line B-B 

0 

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83" 

I 

50 MILES 

I 

50 KILOMETERS 

G9 

B' 

CHILHOWEE 

MOUNTAIN 

BELT 

, FIGURE 9.-Generalized isopach map of the Grainger Formation in eastern Tennessee. Isopach interval 50 meters. 
G10 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Grainger near Chilhowee Mountain. The lower and 

middle parts of the formation consist of gray shale 

and sandy shale that is overlain by massive gray 

sandstone and siltstone. The upper part of the formation consists· of coarser grained and conglomeratic sandstones containing quartz pebbles as much 

as 2.5 em (1 in.) long. The formation contains a 

few beds of foss.iliferous sandy limestone; the fos~ 

sils suggest that the Grainger in this area is of 

Warsaw age. 

Clinch Mountain belt.-The type ai,"ea of the 

Grainger is in the Greendale syncline, along a low 

ridge called Pine Mountain which is. east of Clinch 

Mountain. The Grainger was studied there by 

Sanders (1952) and by Has.son (1972, 1973). 

Sanders (1952) divided the Grainger into four lithologic m.embers, a. basal member, a lower sandstone 

member, a middle siltstone-shale member, and an 

upper sandstone member. The basal member, which 

is 61-91 m (200-300 ft) thick, consists of darkgray argillaceous shale and olive-gray siltstone, thin 

beds of fine-grained sandstone, and a little lim.estone. 

The lower sandstone membe·r ranges from 15.2 to 

61 m (50 to 200 ft) in thickness. along the Greendale syncline in Tennessee. The unit consists of very 

fine grained light-gray sandstone and some pebble 

conglomerate. The middle member of the Grainger 

consists of 122 to 152 m. ( 400 to 500 ft) of gray 

shale and olive-gray siltstone; two glauconite zones 

are in the upper part. Except for the· glauconite 

beds, the middle and basal members are lithologically similar. The upper sandstone member of the 

Grainger consists of as much as 45.7 m (150 ft) of 

very fine grained to coarse-grained feldspathic, 

medium-gray sandstone and some interbedded olivegray silty shale. Cross bedding is. common, and the 

upper part of the member contains pebble conglomerate of vein quartz, quartzite, feldspar, and slate. 

Hasson (1972, 1973) restricted the Grainger Formation in the Greendale syncline to the upper three 

members of Sanders (1952) and correlated the basal 

member with most of the Big Stone Gap Member 

of the Chattanooga Shale in southwestern Virginia. 

Hasson ( 1973) provided two measured sections of 

the Grainger (restricted), one at the type section 

in Grainger County, and another in Hawkins 

County, which he designated as the standard refer~ 

ence section for the formation. Depending upon the 

assignment of the basal m.ember of .the Sanders 

(1952), the Grainger is either 168 or 234 m (552 

or 768 ft) thick at the srtandard reference section. 

Hasson (1972, 1973) concluded that the Grainger 

was of Kinderhook-Osage age, on the basis of 

brachiopods, bryozoans, and crinoid columnals that 

he studied. 

Newman Ridge.-ln the Newman Ridge strike 

belt-the next belt northwest of the Greendale 

syncline-the Grainger Formation is considerably 

thinner than in the Greendale syncline. Near the 

south end of Newman Ridge, the Grainger, as 

mapped by Harris and Mixon (1970) and Harris 

and others (1962), consists of 107-122 m (350-400 

ft) of greenish-gray shale and siltstone, some grayish-red shale is near the middle of the formation, 

and about 6.1 m (20 ft) of thin-bedded greenishgray chert is at the top. 

Pine Mountain block.-The Grainger thins and 

changes markedly to the northwest between its exposures on both sides of the Middlesboro syncline 

on the Pine Mountain block. Near Middlesboro, Ky., 

the formation consists of 91-99 m (300-325 ft) of 

greenish-gray and grayish-red shale containing 

abundant siderite nodules; about 6.1 m. (20 ft) of 

Fort Payne Chert is at the top (Englund, 1964). 

On the northwest side of the Pine Mountain block, 

the Grainger consists: of a maximum of 69 m. ( 225 

ft) of greenish-gray and grayish-red shale containing siderite nodules·. The formation thins and intertongues with the Fort Payne to the ·southwest between Jellico and Pioneer, to where only about onethird meter (a foot) of shale (Maury Formation) is 

at the base of the Fort Payne (Englund, 1968, fig. 

6). Fossils described by Englund (1968, p. 9) show 

that the Grainger is of early Osage age. 

Paul Potter (oral commun., 1976) pointed out 

that the unit mapped as Grainger by Englund 

(1968) at Jellico is lithologically similar to the 

Borden Formation of eastern Kentucky. Like 

Potter, the present writers believe that the term 

Grainger should be used in eastern Tennessee where 

the formaton is thick, sandy, and s.iJty and predominantly gray, whereas the term Borden is more 

appropriate for correlative thinner greenish-gray 

and grayish-red shale of the Jellico-Pioneer area. 

The change in facies from Grainger to Borden lithologies seems to be related to the tectonic setting in 

which the strata were deposited; the Borden was 

deposited on the stable shelf, and the Grainger on 

the shelf edge and in the basin. 

FORT 1PAYNE FORMATION 

The Grainger (or Borden) grades. laterally into 

the Fort Payne Formation ; where the two coexist, 

the Fort Payne overlies the Grainger (Smith, 1890). 

The Fort Payne Formation is widespread in Tennessee; it extends· from the western part of the Val-
TENNESSEE G11 

ley and Ridge, passes beneath the Cumberland 

Plateau, where it crops out along the eastern side 

of Sequatchie Valley and in Elk Valley, to the Highland Rim. The boundary between the Fort Payne 

and Grainger or Borden is shown approximately by 

the zero isopach in figure 9. The formation ranges 

from about 30 to 91 m. (100 to 300 ft) in thickness. 

The base of the Fort Payne is marked almost 

everywhere by the thin (generally about a meter (3 

ft) or less) Maury Formation (Stafford and Killebrew, 1900). The Maury is characteristically a 

greenish-gray to grayish-green shale, mudstone, 

siltstone, or claystone. Phosphate nodules are common and in som.e places, the formation is abundantly glauconitic. The Maury is too thin to map 

separately and is commonly included with the Fort 

Payne. 

The Fort Payne Formation contains several 

lithologies and facies in Tennessee. The stratigraphy 

of the formation has not been studied in detail on 

a regional basis, and much of the description in this 

report was obtained from published geologic quadrangle maps. Wilson (in press) mapped about 76.2 

m (250 ft) of cherty limestone and dolo·mite in the 

Whiteoak Mountain syncline. Englund (1968) described the Fort Payne as consisting of 30 to 53 m 

(100 to 175 ft) of finely crystalline bedded cherty 

dolomite containing greenish-gray shale partings in 

the area of its transition to the Borden Formation. 

In northern Sequatchie Valley, the Fort Payne 

consists of about 61 m (200 ft) of siliceous and 

cherty limestone and dolomite. To the south, the 

formation i·s thinner and more deeply weathered so 

that outcrops consist of beds of crinoidal chert. 

The Fort Payne of the Highland Rim is a heterogeneous mixture of carbonate and terrigenous clastic 

material and a rock described by the Tennessee Division of Geology on many geologic quadrangle maps 

as silicastone. Silicastone is defined by the Tennessee 

Division of Geology in its quadrangle mapping as 

"sedimentary rocks composed of fragmental (siltsize) and/or precipitated silica." 

Calcareous shale and siltst~ne and cherty argillaceous limestone are the dominant lithologies o.f 

the eastern Highland Rim. However, Cho·wns and 

Elkins (1974, p. 887) noted that dolomite, which 

had not been reported by previous workers (see for 

example, Wilson and Barnes, 1968), was present in 

the Fort Payne in the area that they studied. The 

formation ranges from about 21.3 to 39.6 m (70 to 

130 ft) in thickness in the southeastern Highland 

Rim and is 76.2 m (250 ft) or more thick to the 

northeast, near Kentucky. In places, the lower part 

of the formation consists of several meters of greenish-gray to light-olive-gray shale that encapsulates 

beds, bioherms, and lenses of crinoidal limestone 

as much as 9 m (30 ft) thick (fig. 10). Chert is 

abundant throughout the formation in carbonate 

rocks and calcareous siltstones as bands, beds, 

lenses, nodules, or irregularly shaped masses. Two 

silicastone-bearing areas of Fort Payne are in central 

Tennessee, one at the Kentucky line and a larger 

area that appears to extend from the central part of 

the eastern Highland Rim to the southwestern part 

of the western Highland Rim (fig. 10). 

Geodes of quartz are common in the Fort Payne. 

Those studied by Chowns and Elkins ( 197 4) appear 

to be pseudomorphs after anhydrite and are associated with tidal-flat and lagoonal sedimentary sequences. Chowns and Elkins (1974) identified siliceous sponge spicules and spiculite in the Fort Payne 

and Warsaw; these fossils may have been the 

source of the abundant silica in the formation. 

In the southwestern ~ighland Rim, the Fort 

Payne can be divided into an upper cherty facies 

and a lower siltstone facies. The cherty facies consists of irregular rough plates and granules of 

brown, gray, or black chert in a matrix of calcareous 

brown to gray siltstone, and interbedded chert and 

siltstone. The lower siltstone facies consists of gray 

calcareous massively bedded siltstone containing 

siliceous and calcareous geodes and irregular beds 

of chert. Locally, the lower siltstone facies contains 

crinoidal and glauconitic limestone beds, and in 

places it is petroliferous. In this area, the Fort 

Payne ranges in thickness from 61 to 91 m (200 to 

300ft). 

The lower siltstone facies gives way to the 

northeast so that the cherty facies overlies silicastone-bearing strata (fig. 10). The silicastone is 

generally gray to brownish gray and contains various amounts of calcite and dolomite. Chert and 

quartz geodes are common. Olive-gray to brownishor greenish-gray shale is present beside and below 

the silicastone in this area, and crinoidal limestone 

is locally abundant within the shale. 

In the northwestern part of the Highland Rim, 

the upper cherty facies is absent, and the Fort 

Payne is represented mostly by brownish-black, 

brownish-gray, and grayish-black calcareous siltstone. The siltstone in places is shaly, is. cherty, or 

contains quartz geodes. In places, the upper part of 

the Fort Payne contains crossbedded calcarenite 

15.2 m (50 ft) or more below the Fort PayneWarsaw contact, the calcarenite is similar to that 

of the Warsaw Limestone. 
Q1.2. THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

--=::; 

... h .... ;' 

SOE I 

EXPLANATION 

Q Upper cherty facies, lower 

sU tstone facies 

0 SUicastone facies 

Q Basal crinoidal limestone 

D Cherty carbonate siltstone 

and shale 

10 20 MILES 

10 20 KILOMETBlS 

FIGURE 10.-Facies of the Fort Payne Formation in central Tennessee. 

In the north-central Highland Rim, the formation consists of brownish-black to gray cherty calcareous or dolomitic siltstone and shale that is interbedded with gray cherty and silty dolomitic limestone. Lenticular masses and bioherms of crinoidal 

limestone as much as 7.6 m (25ft) thick are present 

in the lower part of the Fort Payne in the western 

and northern Highland Rim (fig. 10). 

In the western valleys of the Tennessee and 

Cumberland Rivers along the Kentucky line, the 

Fort Payne is represented by brown to black dense 

chert interbedded with siliceous shaly limestone 

and calcareous to dolomitic siltstone. Some of the 

chert is in rough irregular plates and granules in a 

siliceous or calcareous matrix. Small siliceous geodes 

are common. The New Providence Shale is a facies 

within the Fort Payne in places in this area and is 

represented by about 6.1 to 21.3 m (20 to 70 ft) of 

medium-gray to grayish-green calcareous and 

glauconitic shale and a few thin beds of silty nodular 

crinoidallimestone. 

The Fort Payne Formation, as mapped by the 

Tennessee Division of Geology, includes all beds 

between the Maury Formation and Warsaw Limestone and is of Kinderhook or Kinderhook-Osage, 

age (Conkin and Conkin, 1975). 

NEWMAN LIMESTONE AND EQUIVALENTS 

The Newman Limestone (Campbell, 1893, p. 38) 

consists of those beds between the top of the Fort 

Payne Formation and the base of the Pennington 

Formation (fig. 2). The unit is mapped as a formation on Newman Ridge and on the Pine Mountain 

block (Mixon and Harris, 1971; Englund, 1964, 

1968). The Tennessee Division of Geology recognizes 

formations within the Newman in the Clinch Mountain strike belt east of Newman Ridge and uses a 

slight modification of the nomenclature proposed by 

Sanders (1952, and unpub. data in the files of the 

Tennessee Division of Geology). Strata equivalent 

to the lower part of the Newman were recognized by 

Neuman and Nelson (1965) in the Chilhowee Moun-
TENNESSEE G13 

tain belt. In the Cumberland Plateau and Highland 

Rim, Newman equivalents are divided into another 

set of formations that are mostly limestone but contain subordinate amounts of sandstone and shale. 

CHILHOWEE MOUNTAIN BELT 

Neuman and Nelson (1965) named the postGrainger Mississippian beds near Chilhowee Mountain the Greasy Cove Formation. The unit consists 

of about 305 m (1,000 ft) of gray argillaceous limestone interbedded with red and gray fine-grained 

sandstone, siltstone, and shale (fig. 8). The top of 

the formation has been cut off by faulting, and 

younger beds,are unknown in this area. Brachiopods 

in limestone beds suggest that the Greasy Cove is 

of Warsaw age. 

CLINCH MOUNTAIN BELT 

The Newman Limestone is estimated to be between 637 and 914 m (2,090 and 3,000 ft) thick in 

the strike belt east of Clinch Mountain (fig. 7), 

where it was subdivided by Sanders (1952), from 

base up,ward, into the: Maccrady Formation, Press:-

mens Home Formation, Laurel Branch Limestone, 

Snow Flake Formation, Clifton Creek Limestone, 

Gilliam Creek Limestone, Fisher Creek Formation, 

Fido Sandstone, and Cove Creek Formation. 

The Maccrady Formation (Stose, 1913) consists 

of about 18.3-21.3 m (60-70 ft) of gray to grayishred claystone, shale, calcareous siltstone, and sandstone. In places, grayish-red siltstone is gypsiferous, 

reflecting the equivalence of the Maccrady in Tennessee to the gypsum-bearing beds of the same 

age in southwestern Virginia. 

The Pressmens Home Formation (J. E. Sanders, 

unpub. data in the files of the Tennessee Division 

of Geology) consists of about 45.7 m (150 ft) of 

calcareous siltstone, sandstone, limestone, and 

dolomite. In places, the limestone is cherty, and the 

unit locally contains 3 to 4.6 m (10 to 15 ft) of 

oolitic limestone near its top at the type section in 

the Pressmens Home quadrangle. 

The Laurel Branch Limestone (Sanders, 1952) is 

composed of very fine grained dark-gray to black 

limestone that contains chert nodules and lenses and 

silicified corals, brachiopods, and bryozoans. The 

unit is about 24.4 m (80ft) thick. 

Sanders (1952) named the Snow Flake Fo·rmation 

for a siltstone unit 36.6 to 39.6 m (120 to 130 ft) 

thick between the Laurel Branch and Clifton Creek 

limestones. The unit is composed of silty shale and j 

siltstone lithologically similar to . the Grainger Formation. The base of the Snow Flake is marked by 

0.3 m (1 ft) of calcareous sandstone. The sandstone 

is overlain by about 30 m (100 ft) of weathered 

silty shale and calcareous siltstone, and then by 2.4 m 

(8 ft) of fissile black limestone and 2.4 m (8 ft) of 

fissile black shale, and at the top by about 3 m (10 

ft) of silty crystalline fossiliferous limestone. 

The Clifton Creek Limestone (Sanders, 1952) is 

composed of about 39.6 m (130 ft) of dark-gray to 

black finely crystalline limestone containing small 

scattered nodules' of black chart. Dark-gray oolitic 

limestone that is 0.3 m (1 ft) thick is about 7.6 m 

(25ft) below the top. 

The Gilliam Creek Limestone (S~nders, 1952) is 

about 122 m ( 400 ft) thick and consists typically of 

cherty gray to brownish-gray limestone, some argillaceous to silty, and some containing "porphyritic" 

crystals of calcite in a matrix of aphanitic rock. In 

general, the unit consists in its lower part of 40 m 

(130ft) of medium crystalline limestone containing 

0.6 m (2 ft) of oolitic limestone 12.2 m ( 40 ft) above 

the base. Next above is 18.3 m (60ft), more or less, 

of silty aphanitic and cherty limestone, above which 

is 3. 7 m ( 12 ft) of very coarsely crystalline calcarenite. The upper part of the formation is composed of 

interbedded cherty and silty limestone. 

The Fisher Creek Formation (Sanders, 1952) consists of three members. The lower member is composed of about 152 m (500 ft) of coarse silty laminated gray limestone, gray crossbedded calcarenite, 

greenish-gray to yellowish-gray shaly and calcareous 

siltstone, and fine-grained gray limestone. The 

middle sandstone member of the Fisher Creek Formation consists of 15.2 m (50ft) of medium-grained 

calcareous gray sandstone in beds 15-30 em ( 0.5-

1 ft) thick; in places, the sandstone grades laterally 

into calcarenite. The upper member of the Fisher 

Creek Formation consists of about 305 m (1,000 ft) 

of interlaminated gray limestone, coarser silty limestone, greenish-gray calcareous siltstone, and finegrained gray limestone. Massive calcarenite beds are 

present in subordinate amounts. 

The Fido Sandstone of Butts (1927) consists 

6.1-15.2 m (20 to 50 ft) of very fine to medium.-

grained gray calcareous sandstone or grayish-red 

sandy calcarenite in the Clinch Mountain belt. The 

formation is commonly crossbedded and in places 

contains fossil frag1nents. 

The Cove Creek Formation of Butts ( 1927) consists of three members in the Clinch Mountain belt 

in Tennessee, a lower limestone member, a middle 

sandstone member, and an upper limestone member. 

The lower member consists of 68.6-107 m (225-350 
G14 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

ft) of massive argillaceous limestone containing 

laminations, ribbons, and discontinuous lenses of 

quartz sand. The middle member is composed of 

about 15.2 m (50ft) of fine- to medium-grained gray 

calcareous sandstone and sandy calcarenite. The 

upper member consists of gray argillaceous or shaly 

limestone interlaminated with siltstone. The member 

is about 30m (100ft) thick, and the total thickness 

of the Cove Creek Formation of Butts (1927) 

ranges from 122 to 152 m ( 400 to 500 ft) in Tennessee. 

The names Cove Creek Limestone and Fido Sandstone were abandoned by the U.S. Geological Survey 

on the basis of a report by Wilpolt and Marden 

(1949). They replaced the name Cove Creek Limestone by the name Bluefield Formation, which has 

precedence, and the Fido was determined to be 

equivalent to the lower part of the Bluefield and the 

upper part of the Greenbrier Limestone (Keroher 

and others, 1966). For this reason, the Cove' Creek 

and Fido should not be perpetuated in the stratigraphic nomenclature for Mississippian strata in 

Tennessee, and a set of local names should be proposed. 

The great thickness and lithologic aspects of the 

Newman Limestone in the Greendale syncline suggest that it is largely a slope deposit marginal to 

the carbonate platform. However, detailed petrologic studies have not yet been made. 

NEWMAN RIDGE AND p,JNE MOUNTAIN BLOCK 

The Newman Limestone consists of a lower limestone member and an upper limestone and shale ~~ 

member on Newman Ridge and on the Pine Mountain block (Mixon and Harris, 1971 ; Harris and 

Mixon, 1970; Harris and others, 1962, Harris, 1965; I 

Engund, 1964, 1968). The formation thins from 

241m (790ft) on Newman Ridge to a maximum of 

223 m (730 ft) along Cumberland Mountain to no 

more than 210m (690ft) in Elk Valley. 

The formation is more calcareous to the northwest, primarily because of an increase in thickness 

of the lower limestone member. This member is 

composed of about 70 m (230 ft) of chert-bearing 

light-olive-gray. calcilutite interbedded with bioclastic and oolitic limestones on Newman Ridge and of 

79 m (260 ft) of similar lithologies along Cumberland Mountain; in Elk Valley, the lower member 

is 122-131 m (400-430 ft) thick and its lowest 

6.1 m (20ft) consists of finely crystalline olive-gray 

or dolomitic argillaceous limestone that contains 

lenses of coarse sand and jasper-bearing conglomerate. This basal unit is overlain by oolitic and bioclastic gray limestone that contains thin beds of 

greenish-gray or grayish-red shale. 

The upper member is about 171 m ( 560 ft) thick 

on Newman Ridge and consists of greenish-gray 

shale and siltstone interbedded with olive-gray calcilutite, argillaceous calcilutite, and medium-grained 

oolite. In the Cumberland Mountain belt, the upper 

members consists of 99 m (325 ft) or more of 

medium-gray calcareous shale interbedded with 

medium-gray to olive-gray calcilutite and oolitic, bioclastic limestone. In Elk Valley, the correlative unit 

is composed principally of gray, greenish-gray, and 

grayish-red shale interbedded with fine- to coarsegrained limestone or argillaceous limestone and is 

67.1-100.6 m (220-330 ft) thick. 

The Mississippian section on I-75 south of Jellico 

was studied in detail by members of a Sedimentation 

Seminar at the University of Cincinnati, and a detailed report of the seminar is being published by 

the Tennessee Division of Geology (in press). Significantly, the seminar group was able to identify in 

the Newman at Jellico the formations typical of the 

Mississippian section in the Cumberland Plateau to 

the west and south, including a bit of the Warsaw, 

the St. Louis, Monteagle, Hartselle, and Bangor. 

The Newman (or Bangor) -Pennington contact 

is picked differently by different workers. In the Elk 

Valley region, Englund (1968, p. 13) mapped the top 

of the Newman at the base of 6.1 m (20 ft) of massive sandstone, placing the considerable thickness 

of interbedded shale and limestone beds below in 

the upper member of the Newman. In Tennessee, 

other workers map the base of the Pennington lower 

in the section, selecting as a matter of convenience 

the base of yellowish-gray weathering silty dolomite 

beds a little above the solid limestone of the Bangor. 

The reader should be aware, therefore, that the 

upper member of the Newman Limestone, as mapped 

in Newman Ridge and on the Pine Mountain block, 

may include correlatives to beds mapped elsewhere 

within the lower part of the Pennington Formation. 

CARBONATE PLATFORM DEPOSITS OF THE 

CUMBERLAND PLATEAU AND HIGHLAND RIM 

Beneath the Cumberland Plateau and Highland 

Rim, the Fort Payne Formation is overlain by a 

carbonate sequence containing minor amounts of 

sandstone and shale. On the eastern side of the 

Nashville dome, the sequence is divided into the 

Warsaw, St. Louis, and Monteagle Limestones, the 

Hartselle Sandstone, and the Bangor Limestone 

(figs. 11 and 12). West of the dome, where the upper 
TENNESSEE G15 

B c D 

.. Rockcastle Conglon:'e.ra~e. ··:...;,··~·· ~xq:x::: 

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VandeverForrnatio~=::= 

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Chattanooga Shale / _/ / 

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/ -17 

MET~~LFEr 

60 200 

O 5 10 MILES 

5 1 0 15 KILOMETERS 

FIGURE 11.-Stratigraphic cross section along line B-C-D. 

part of the section is removed . by erosion, the Ste. 

Genevieve Limestone occupies the position of the 

Monteagle. 

WARSAW LIMESTONE 

The Warsaw Limestone (Hall, 1857) is 15-55 m 

(50 to 180 ft) thick on the eastern Highland Rim. 

It is distinguished from the Fort Payne and the 

St. Louis by the character of its chert; chert in the 

Warsaw is mostly porous or spo'ngy, whereas chert 

in the adjacent formations is dense and hard. 

In the southern part of the Cumberland Plateau 

and eastern Highland Rim, the Warsaw is composed 

of slightly cherty brown to gray, medium- to coarsegrained bioclastic limestone. In some places the formation is sandy, silty, or dolomitic. 

Terrigenous clastic content increases generally to 

the north, so that the Warsaw in the east-central 

Highland Rim consists of dark-gray to brownishgray sandy and silty limestone, which is bioclastic 

in part. In places, calcareous shale, siltstone, and 

argillaceous limestone are the dominant lithologies, 

and these are commonly interbedded with bioclastic 

calcarenite. Silicastone containing quartz geodes is 

common in the lower part of the formation in some 

places. 

On the. northeastern part of the Highland Rim 

along the Kentucky line, the Warsaw is composed 

mostly· of calcareous crossbedded very fine to 

medium-grained sandstone that grades laterally 

within short distances into crossbedded silty or 

sandy bioclastic limestone. 

On much of the western Highland Rim, the Mississippian limestones are weathered to a rubble of 

chert and clay. Where preserved in that area, the 

Warsaw is represented by 12-61 m (40-200 ft) of 

gray, yellowish-brown, brownish-gray, or olivegray fine- to coarse-grained limestone. The limestone is commonly crossbedded and bioclastic and in 

places is glauconitic. Some is silty or dolomitic. Local 

oolitic limestone beds at the top of the Warsaw are 

regarded as possible equivalents to the Salem Limestone of nearby States. Chert is common in the formation as nodules, lenses, and large irregular 

masses. Dolomitic limestone, silty dolomite, and 

sandy siltstone are also common in the formation, 
G16 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

c ••• 0 

.. 

·· .. ·. METERS FEET 

C' 

120-r- 400 

60-~ 200 

. . . 5 I 10 MilES L.....--r-......L.."T""""""-~1 0 I I I 

5 10 15 KllOMffiRS 

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anaor Limestone 

rtseue ~an . .., ...... ·.·:.··· .......................... . ..L 

- Monteag~ ...... umest 

and these generally are brownish gray to yellowish 

brown, are cherty, and contain small siliceous 

geodes. 

ST. LOUIS LIMESTONE 

The St. Louis Limestone (Engelmann, 1847) generally ranges from 12 to 55 m ( 40 to 180 ft) in thickness on the eastern Highland Rim. In the southeastern Highland Rim, the St. Louis is composed 

mostly of yellowish-gray, yellowish-brown, and gray 

very fine to medium-grained dolomitic limestone and 

dolomite containing balls and doUs of dense paleblue to bluish-gray chert. Gray bioclastic limestone 

is common in some places and locally contains fragments of algae, crinoids, and brachiopods. · 

Northeastward along its outcrop the St. Louis 

consists of medium- to medium-dark-gray, brownishgray, or light-olive-gray limestone, containing beds 

of brownish-gray to yellowish-brown, fine-grained 

dolomite a:nd walnut- to baseball-sized spherical 

chert cannonballs. Quartz geodes are common in 

some places. Some beds contain calcite bird's eyes, 

and some are petroliferous. In places, the formation 

contains thin beds of greenish-gray shale. Foraminifera were observed in several places in the formation along the Kentucky line and on the western 

Highland Rim. 

The St. Louis Limestone ranges from 45.7 to 

108.2 m (150 to 355ft) in thickness on the western 

Highland Rim but more commonly is about 61 m 

(200ft) thick. There the formation consists of fineto coarse-grained yellowish-gray, yellowish-brown, 

and gray limestone and silty or dolomitic limestone. 

Some is crossbedded and bioclastic, but more commonly beds are thick to massive. Thin oolitic zones 

are present locally within the unit. In places, the 
TENNESSEE G17 

upper part of the St. Louis consists of fine- to 

medium-grained gray limestone that contains 

abundant rounded cannonballs of chert. These beds 

overlie poorly sorted calcarenites that are locally 

petroliferous. Elsewhere cherty calcareous siltstones 

or silty dolomite beds as much as 6.1 m (20ft) thick 

mark the base of the formation. 

The formation is characterized by more or less 

abundant Lithost1·otion proliferum and Lithostrotionella castelnaui, and these fossils together with 

the cannonball cherts are the key to identification 

of the unit. 

MONTEAGLE AND STE. GENEVIEVE LIMESTONES 

The Monteagle Limestone (P. R. Vail, 1959; in 

Stearns, 1963, p. 4-8) consists of 45.7-115.8 m (150-

380 ft), commonly about 76 m (250 ft), of light- to 

medium-gray and light-olive-gray bioclastic and 

oolitic limestone and some beds of light-gray to 

light-olive-gray, .bird's-eye-bearing micrite. Greenish-gray to olive-gray shale and yellowish-gray 

dolomitic interbeds are common in some sections, 

but are only a small part of the formation. Mediumto dark-gray and bluish-gray chert is present locally 

in some beds but is generally not abundant. A yellowish-gray to yellowish-orange, porous bryozoanbearing chert (Lost River Chert of Elrod, 1899) 

serves as a marker bed near the base of the formation. The porous chert is produced by weathering of 

siliceous limestone beds in a zone 1 m (3 ft) or less 

thick and is common as blocks or pieces in the soil 

overlying the zone. In some places, scattered sand 

grains are in limestone beds near the base of the 

·formation. 

The Ste. Genevieve Limestone (Shumard, 1860) 

on the northwestern Highland Rim is stratigraphically equivalent to the lower part of the Monteagle 

Limestone on the eastern Highland Rim and plateau. 

The Ste. Genevieve consists of about 61 m (200 ft) 

of rock lithologically similar to that of the Monteagle. The Lost River Chert of Elrod (1899) persists to the western Rim and serves there too as 

marker beds 3-6.1 m (10-20 ft) above the base of 

the formation. Only in the structurally deformed 

Wells Creek basin area of the northwestern Highland Rim have Mississippian beds younger than the 

Ste. Genevieve been preserved. In this area, a graben 

contains about 61 m (200 ft) of beds younger than 

the Ste. Genevieve; these beds have been tentatively 

correlated with the Renault, Bethel, and Paint Creek 

Formations of western Kentucky. 

Depositional environm·ents of carbonate sands 

near Monteagle, Tenn., ranged from shoals .to the interior platform (Bergenback and others, 1972). 

Shoal deposits of crossbedded oolitic carbonate sands 

are separated by subaerial crusts, represented by micrites containing fenestral fabrics and laminae; the 

crusts formed during brief periods of emergence. 

Brecciated nodular beds of micrite and dololutite are 

interpreted to represent caliche paleosols. Oolitic 

sands of tidal and marine sand deposits grade into 

poorly sorted, burrowed, pelletal, and bioclastic 

sands that accumulated in interior platform environments. 

HARTSELLE FORMATION 

The Hartselle Formation (Smith, 1894), a persistent clastic unit in the predominantly carbonate 

sequence, is as much as 27.4 m (90 ft) thick. In 

general, the Hartselle consists of olive-gray to 

greenish-gray shale, silty shale, and rippled to crossbedded, grayish-orange, yellowish-brown, and gray 

sandy limestone and calcareous sandstone. In places 

where the clastic unit is absent, the stratigraphic 

interval is marked by yellowish-gray dolomite. Zones 

of oolitic and bioclastic limestone are near the base 

of the formation in some places. Where sandstone is 

the dominant lithology, the Hartselle forms a prominent topographic bench along the western Cumberland Escarpment between the surfaces of the Highland Rim and Cumberland Plateau. The Hartselle is 

generally thin or absent in southern Tennessee; 

where present, it is represented mostly by shale. The 

formation thickens and becomes more sandy along 

its outcrop to the north, but in the subsurface to 

the northeast it thins and grades into a shaly facies. 

BANGOR LIMESTONE 

The Bangor Limestone (Smith, 1890) consists of 

24.4 to perhaps 152.4 m (80 to 500 ft) of mediumgray to medium-dark-gray, or brownish-gray limestone. The Bangor is commonly petroliferous and is 

generally darker and more argillaceous than the 

Monteagle. The formation generally contains oolitic 

and bioclastic beds. A few thin beds are dolomitic 

and pale yellowish brown ; thin beds of greenishgray to olive-gray shale are common. The formation 

generally contains lenses and nodules of mediumgray to medium-dark-gray chert. The Bangor is 

thickest in the southeastern part of the Cumberland 

Plateau, thinning generally to the west across the 

plateau and to the north into Kentucky. 
G18 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

PENNINGTON FORMATION 

The Pennington Formation (Campbell, 1893) is a 

heterogeneous unit composed of dolomite; limestone ; red, green, or gray shale ; fine-grained sandstone; and conglomeratic sandstone. In general, the 

formation ranges in thickness from 30 to 152.4 m 

(100 to 500 ft). On the eastern side of the plateau, 

the Pennington is thicker and contains a greater 

proportion of terrigenous clastic· deposits; to the 

west, it is thinner and more calcareous. 

The Pennington may be divided into five stratigraphic units that have some lateral continuity 

(Vail, 1959). Silty, yellowish-gray and light-olivegray to brownish-gray fine-grained dolomite beds in 

a zone ranging from 1 to 10 m (3.3-33 ft) in thickness commonly mark the base of the formation. In 

some places, the dolomite contains quartz-filled 

geodes, and less commonly it contains vugs filled 

with celestite or strontianite. Frazier (1975) concluded that celestite-bearing geodes in Fentress 

County are replacements of gypsum nodules that 

formed a little way beneath the surface of a sabkhalike environment. The basal dolomite zone is in 

many places overlain by limestone, succeeded by 

beds of red and green shale, fine-grained sandstone 

or quartz-pebble conglomerate, an upper limestone 

unit, and locally by some shale and sandstone at top. 

Limestone beds generally resemble those of the 

Bangor and are gray, oolitic to bioclastic, and, in 

places, shaly. 

In Tennessee, the Pennington contains beds that 

were deposited in littoral (but nondeltaic) depositional environments. Bergenback, Horne, and Inden 

(1972) recognized that the Pennington near Monteagle contains units deposited in tidal flat, tidal 

channel, levee, and intertidal environments. Milici 

( 197 4) described fine-grained sandstones within the 

Pennington as representing offshore sandbars 

formed from fine sand and clay winnowed by waves 

and longshore currents from beach sands. A regional 

stratigraphic cross section (fig. 13) shows that 

quartz-pebble conglomerates on the northeast can be 

traced southwestward into fine-grained sandstone 

typical of the Pennington. According to Englund 

and Smith (1960) and Englund (1968), these conglomerates are tongues of Lee in the Pennington in 

northeastern Tennessee and adjacent parts of Virginia and Kentucky. As shown in the cross section 

(fig. 13), these tongues are in places overlain by red 

and green Pennington shale and appear to pass laterally below beds of limestone. 

In southern Tennessee, similar beds of quartzpebble conglomerate interbedded with olive-gray to 

dark-gray carbonaceous shale and siltstone and thin 

coal are called Gizzard and are considered to be of 

Mississippian or Pennsylvanian age (Milici, 1974). 

Englund (1968) classified strata similar to those in 

the Gizzard as Pennington and placed the top of the 

Pennington (base of Lee) at a higher stratigraphic 

level. The Pennington-Gizzard problem and its relation to the nature of the Mississippian-Pennsylvanian boundary was discussed by Milici (1974). 

THE COAL MEASURES 

The coal-bearing strata of Tennessee are mostly 

of Early and Middle Pennsylvanian age (fig. 3) and 

are divided generally into a lower sequence of thick 

orthoquartzite interbedded with shale and some 

coal, and an upper sequence dominated by shale but 

containing subsidiary amounts of sandstone and 

much more coal than the lower sequence. This basic 

div.ision is apparent in the stratigraphic cross section of the northern Cumberland Plateau (figs. 7, 

13-15). Wilson and Stearns (1960) recognized this 

dichotomy, referring to the orthoquartzites as 

blanket sandstones and to the upper sandstones as 

digitate. Ferm (1974) showed that on a regional 

basis, the progradational sequence from Pennington 

red and green shale, limestone and fine-grained 

argillaceous sandstone through the orthoquartzite 

to the section dominated by shale and many coal 

beds represented a transition from marine deposits 

to littoral deposits and then to delta-plain facies. 

Units deposited in shoreline environments are evident in the Gizzard and Crab Orchard Mountains 

Groups and persist perhaps into the lower part of 

the Crooked Fork Group. Quartzose barrier sandstones (deposited in beaches, tidal deltas, tidal chan-. 

nels, washovers, and bars) are abundant in the 

Gizzard and Crab Orchard Mountains Groups (Ferm 

and others, 1972; Milici, 1974; this report, fig. 3). 

Sandstone formations vary widely in thickness, generally ranging from 10 to 100 m ( 33 to 328 ft) , 

. although composite sandstone bodies 91-122 m 

(300-400 ft) thick are known in a few places. 

Quartz-pebble conglomerate and conglomeratic sandstone characterize each of the blanket sandstones in 

some places. However, the Sewanee and Rockcastle 

Conglomerates almost everywhere contain at least 

a few quartz pebbles. Thick dark-gray shale associated with the orthoquartzite sandstone bodies is 

thought to have been deposited in back-barrier 

lagoons. In places, this shale is calcareous and contains marine fossils. Elsewhere, it grades through 

. burrowed and flasered beds, interpreted to be tidal 

flats, into sandstone. Coal beds are associated with 
TENNESSEE G19 

D E' F' D' 

~~ 

J~ --- ---

MET~~~LFE~ 

60 200 

O 5 MILES 

5 KILOMETERS 

FIGURE 13.-Stratigraphic cross section along line D-E'-F'-D' 

these back-barrier-fill seque~ces, and· in places, 

marsh deposits are characterized by thick zones 

containing fossil roots and by anastomosing channel 

fills of sandstone, shale, and siltstone. 

GIZZAR!D GROUP 

The Gizzard Group (Safford, 1869) is composed of 

three formations, the Raccoon Mountain Formation, 

Warren Point Sandstone, and Signal Point Shale. In 

southern Tennessee, the boundary between the Raccoon Mountain and Pennington Formations is picked 

at the top of the highest red or green shale or limestone, and in a few places, at the top of recognizable 

Pennington Sandstone. This convention generally 

separates coal-bearing beds above from the main 

mass of marine strata below. 

The convention used for selecting the top of the 

Pennington in southern Tennessee does not work 

well around the periphery of the Wartburg basin, 

where the stratigraphic reconstruction (fig. 13) 

illustrates a complex facies between the Pennington 

and the Gizzard, wherein quartz-pebble conglomer-
G20 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

E E' 

Windrock coal bed 

Blue Gem coal bed ~ 

Poplar Creek coal bed 

METERS FEET 

120L00 

60 200 

5 MILES 

0 

5 KILOMETERS 

FIGURE 14.-Stratigraphic cross section along line E-E'. 

ate, coal, carbonate deposits, and red beds intertongue both laterally and vertically. Similar facies 

variations were reported by Horne· and others 

(1974) along the Mississippian-Pennsylvanian boundary in northeastern Kentucky and by Englund and 

Smith (1960) and Englund (1968) in northern Tennessee and adjacent States. 

Raccoon Mountain Formation.-The Raccoon 

Mountain Formation (Wilson and others, 1956) consists of a few tens of meters to about 91 m (300 ft) 

of gray shale, siltstone, sandstone, and coal. In some 

places in southern Tennessee, the Raccoon Mountain 

Formation is thick, it contains as many as seven 

coal beds in the Sale Creek and Raccoon Mountain 

coal basins (Milici, 1974). These coal beds are mostly 

thin and discontinuous, although some are of good 

grade and were extensively mined at one time. 

Warren Point Sandstone.-The Gizzard Group is 

divided by separating out the Warren Point Sandstone (Nelson, 1925), which is a persistent mappable unit in southern Tennessee. Where thick, the 

formation consists of 30-91 m (100-300 ft) of fine 

to coarse sandstone that in places contains abundant 

quartz pebbles. In places, thin shale and coal beds 

interrupt the sequence of massive sandstone. Where 

the Warren Point thins to several meters and is indistinguishable from the sand in the Raccoon Mountain, the Gizzard is divided into informal map units. 

Regionally, the Warren Point consists of a series of 

laterally discontinuous lenticular sand bodies, which 
TENNESSEE G21 

F 

Coal Creek coal seam 

Chattanooga Shale 

MET~~~L~~~ 

60 200 

5 MILES 

0 

5 KILOMETERS 

F' 

FIGURE 15.-Stratigraphic cross section along line F-F' 

are correlated by position in sequence to the type 

area. In this way, Gizzard sandstone bodies in the 

subsurface of northern Tennessee are correlated 

with Warren Point Sandstone in southern Tennessee 

(figs. 11-14). 

Signal Point Shale.-The Signal Point Shale (Wilson and others, ·1956) consists generally of 20-55 m 

(66-180 ft) of gray shale, siltstone, thin sandstone, 

and a few thin coal beds. Where mappable, this finegrained clastic unit separates the massive sandstone 

and conglomeratic sandstone of the Warren Point 

Sandstone from the Sewanee Conglomerate. In many 

places, the Signal Point is missing, and coarse 

quartz-pebble conglomerate and conglomeratic sandstone of the Sewanee lie upon the Warren Point. In 

a few places, the entire Gizzard is missing, and the 

Sewanee rests directly on the Pennington Form~ 

tion. Where the Sewanee and Warren Point are 

lithologically similar, they are mapped together as a 

thick composite sand body. Coal beds within the 

Signal Point are mostly thin, discontinuous, and 

only locally important. 
G22 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

CRAB ORCHARD MOUNTAINS GROUP 

The Crab Orchard Mountains Group (Wilson and 

others, 1956) includes the Sewanee Conglomerate, 

Whitwell Shale, Newton Sandstone, Vandever Formation, and Rockcastle Conglomerate. The group is 

represented by these five formations in the southem Cumberland Plateau and in the Crab Orchard 

Mountains. On the northwestern part of the plateau, 

the lower stratigraphic units grade laterally into 

the Fentress Formation, and only the Rockcastle 

persist's as a mappable unit (Wilson, 1956). 

Sewanee Conglomerate.-The Sewanee Conglomerate (Safford, 1893) is the most persistent stratigraphic unit in the Tennessee coal measures. The 

formation ranges generally from 24.4 to 27.4 m (80 

to 90 ft) in thickness, but in some areas it is as 

much as 61 m (200ft) thick. It is composed of fineto coarse-grained sandstone and contains pebbles, 

which are locally abundant. In several places, the 

formation thins to several meters, and the quartz 

pebbles are absent. The Sewanee Conglomerate is 

exposed on much of the southern plateau, is easily 

recognizable in the subsurface of the Wartburg 

basin (fig. 13), but thins to the northwest where it 

grades into the Fentress Formation (figs. 14, 15). 

Whitwell Shale.-The Whitw·en Shale (Butts and 

Nelson, 1925) consists of about 10 m (33 ft) to as 

much as 61 m (200 ft) of gray shale, silty shale, 

sandstone, and coal. The formation contains most of 

the commercial coal in the southern plateau (fig. 

16). The most widely prospected seam is the Sewanee, which is generally within the lower half or 

third of the formation. The Richland coal bed, 

which is at or near the base of the Whitwell, is also 

of commercial quality. As many as four seams are 

within the Whitwell in some areas, but there individual coal beds are too thin to be commercially expoitable. 

In the past, most of the mining of the Sewanee 

and Richland coal beds was in the southern part of 

the plateau, near Whitwell and Tracy City, and this 

is still the area of greatest activity. The quadrangle~~ 

northeast of the Whitwell-Tracy City district and 

the area west of Rockwood contain sizable coal reserves. Most of the Sewanee and Richland coal is 

marketed either as steam coal or, after being 

washed, as metallurgical coal. Although Whitwell 

coal is currently being prospected by deep core drilling, some areas in the southern plateau are relatively 

untested. 

Newton Sandstone.-The Newton Sandstone 

(Nelson, 1925) · consists generally of about 10 m 

(33 ft) to as much as 45.7 m (150 ft) of fine- to 

medium-grained sandstone. In some places, the formation is coarse grained, contains quartz pebbles, 

and is conglomeratic. The formation is generally 

persistent in the southern plateau, between the 

shale and siltstone of the Whitwell and Vandever. 

In a few places, the Whitwell Shale is absent, and 

the Newton rests directly upon the Sewanee. The 

Newton Sandstone is below drainage in the Wartburg basin, where it consists of sandstone, some of 

which contains quartz pebbles (figs. 13-15). Like 

other formations of the Crab Orchard Mountains 

Group, the Newton grades northwestward into shale 

and siltstone of the Fentress Formation. 

Vandever Format·ion.-The Vandever Formation 

(Nelson, 1925) ranges generally from 61 to 137 m 

(200 to 450 ft) in thickness and consists mostly of 

shale and sandstone and some siltstone and coal 

beds. The formation is divided into three members 

in the southern plateau. The upper and lower members, which consist of shale, minor siltstone, thin 

sandstone, and coal beds, are separated by a middle 

sandstone member. Where the sandstone member is 

thick and conglomeratic, it is mapped as the Needleseye Conglomerate Member of the Vandever Formation (Luther and Swingle, 1963). The Vandever Formation contains two main coal beds, the Lantana 

seam in the lower member and the Morgan Springs 

near the top of the upper member. Both of these 

seams are generally suitable for steam coal. 

In the subsurface of the Wart burg basin, the 

Vandever consists of anastomosing sandstone, conglomeratic sandstone, and shale containing beds of 

coal (fig. 13). The top of the Vandever is difficult to 

select in this region because of irregular facies variations in the formation. 

Fentress Formation.-The Fentress Formation 

(Glenn, 1925) consists of the interlaminated and 

flasered shale and fine sandstone and thin beds of 

sandstone and coal between the top of the Pennington and the base of the Rockcastle Conglomerate 

along the northwestern side of the Cumberland 

Plateau. The Fentress Formation is as much as 

76.2 m (250ft) thick. Like the facies in the Gizzard, 

those in the Fentress are extremely variable, and 

both formations are overlain by blanket orthoquartzites. 

Rockcastle Conglomer·ate.-The Rockcastle Conglomerate (Campbell, 1898) is a widespread blanket 

orthoquartzite throughout much of the central and 

northwestern parts of the Cumberland Plateau. In 

general, the formation ranges from 30 to 91 m (100 
TENNESSEE G23 

36oOO'r--___ __;1;.5'----~-~---=8:::::S'.y.OO:..'~----r------t7~~---; 

0 

I 

, .. 

I 

5 

10 MILES 

I 

10 KILOMETERS 

D . 

EXPLANATION 

Area underlain by Sewanee and 

Richland coal seams 

Deep mined areas 

Strip mine, or strip mined and 

augered area 

FIGURE 16.-Areas underlain by, and areas mined out of, the Sewanee and Richland coal seams in the southern 

Cumberland Plateau, Tennessee. 
G24 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

to 300 ft) in thickness and consists of fine- to coarsegrained, loca1ly conglomeratic sandstone. The formation generally contains a widespread shale and 

coal bed (Nemo) near the middle. To the east, shale 

interbeds are more common and thicker and, like the 

Vandever, the formation consists of anastomosing 

shale and sandstone and thin coal beds (figs. 13-15). 

The Rockcastle can thus be divided regionally into 

a barrier phase consisting generally of orthoquartzite to the west, and a back barrier phase of orthoquartzite, shale, and coal to the east. 

CROOKED FORK GROUP 

The Crooked Fork Group consists of a succession 

of six shale and sandstone formations (fig. 3) : the 

Dorton Shale (Wilson and others, 1956), the Crossville Sandstone (Wanless, 1946), the Burnt Mill 

Shale (Wilson and others, 1956), the Coalfield Sandstone (Wilson and others, 1956), the Glenmary 

Shale (Wilson and others, 1956), and the Wartburg 

Sandstone (Keith, 1896). The Crooked Fork Group 

crops out around the periphery of the Wartburg 

basin and in belts on either side of the Crab Orchard 

Mountains (Hardeman and others, 1966). The group 

ordinarily ranges from 91 to 122 m (300 to 400 ft) 

in thickness and is the uppermost to contain thick 

sandstone. However, the sandstone of the Crooked 

Fork is not nearly as thick or laterally persistent as 

that in the groups below. 

The formations within the Crooked Fork range 

generally from 20 to 30 m ( 66 to 100 ft) in thickness, 

although locally several were mapped as 45.7 m 

(150 ft) thick. The shale is generally medium to 

dark gray and in places is interbedded with siltstone or thin sandstone. Sandstone is commonly fine 

to medium grained but in places may be coarser. 

Quartz pebbles are uncommon within the sandstone 

but are present in the Crossville and Wart burg 

sandstones in an area north of the New River. Although the depositional environments of the 

Crooked Fork Group have not been studied in detail, 

it is apparent that these beds are transitional between the littoral beach-barrier sequence below and 

the delta-plain sequence above. 

The only coal bed of significance in the group is 

. the Rex, which is at or near the base of the Dorton 

Shale. In places, the Rex is thick enough to be commercially exploitable and after washing may be 

suitable as a metallurgical grade coal. The Poplar 

Creek coal bed at the top of the group is of local 

commercial significance. 

DEL TA-PL·AIN SEQUENCE 

In Tennessee the beds above the Wart burg Sandstone are divided into six formations, all named by 

Wilson, Jewell, and Luther (1956): the Slatestone 

Formation, Indian Bluff Formation, Graves Gap 

Formation, Redoak Mountain Formation, Vowell 

Mountain Formation, and Cross Mountain Forma,.. 

tion (fig. 3). Wils·on, Jewell, and Luther (1956) 

originally described the thick units as groups, but 

when it became apparent that they could not be 

easily divided into mappable units, they were reduced in rank to formations (Hardeman and others, 

1966). 

Slates tone Formation.-The Slatestone Formation 

consists of 91 to 219m (300 to 720ft) of gray shale 

and subsidiary amounts of siltstone and silty sandstone. The formation includes the strata between 

the top of the Poplar Creek coal bed and the top• of 

the Jellico coal bed. The formation consists of gray 

clayey to sandy shale that in places is separated into 

members by four mappable fine- to medium-grained 

sandstones, named by Wilson, Jewell, and Luther 

(1956) the Stephens, Petros, Sand Gap, and Newcomb sandstones. The sandstones are lenticular and 

commonly are 10m (30ft) or more thick but rarely 

are more than 30m (100 ft) thick. Important coals 

within the formation ar·e the Coal Creek, Petros, 

Blue Gem, and Jellico coals. The Coal Creek and the 

Jellico are the most extensively mined and have the 

largest reserves in the formation. 

Coal Creek coal bed.-The Coal Creek coal bed 

underlies much of the northern Tennessee coal field 

(fig. 17). It is a high-quality steam coal (table 1). 

Thicknesses may be as much as 1.65 m (5.42 ft), 

but they vary greatly within short distances. A 

rider seam commonly is about 6.1 m (20 ft) above 

the coal. Recoverable reserves of the Coal Creek coal 

are in Anderson, Campbell, and Claiborne Counties. 

Additional reserves are in Morgan and Scott Counties in a coal seam that is variously correlated either 

with the Poplar Creek or with the Coal Creek. Because evidence is not available to resolve the correlation problem, the two areas are separated by a 

dashed line in figure 17. For convenience, however, 

the coal tonnage is included with the Coal Creek 

even though the correlation is uncertain. Total recoverable reserves of the Coal Creek coal are approximately 190 million short tons. 

Extensive underground mining of the Coal Creek 

seam began in 1870 and continued into the 1950's in 

Anderson County near Oliver Springs, Briceville, 

Lake City, and Eagan (fig. 17). Today, the only 
Scnm 

Moisture 

Sewanee --- 3.04 

Coal Creek _ 3.47 

Jellico ----- 3.06 

Big Mary __ 3.08 

Pewee ----- 3.60 

TENNESSEE 

TABLE !.-Representative analyses and rank of selected Tennessee coal beds 

[Data from Luther, 19'5>9·, and Johnson and Luther, 1'9172] 

Proximate Ultimate 

percent percent Heat 

value 

Volatile Fixed (btu) matter carbon Ash Sulfur Hydrogen Carbon Nitrogen Oxygen 

29.21 58.17 9.62 0.93 4.96 75.29 1.48 8.16 13,099 

36.44 55.49 4.67 1.34 5.42 76.26 1.86 9.64 13,760 

36.79 53.53 6.68 2.20 5.54 77.06 1.89 8.6 13,509 

36.0 49.67 11.27 3.12 5.1 70.83 1.49 8.51 12,667 

36.81 54.23 5.7 .68 5.55 78.73 1.65 10.18 13,571 

Ash 

softening 

temperature/"F 

2,532 

2,030 

2,304 

2,304 

2,421 

1 Ranked nccordi,ng to Standard Specifications for Classification of Coals by Ra·nk of the American Society for Testing and Materials, ~Abbreviations. 

hvAb=high-volatilc A bituminous. 

hvBb=high-volatilc B bituminous. 

hvCb=high-volntile C bituminous. 

G25 

Rank 

average 1 

hvAb2 

hvBb 

hvBb 

hvCb 

hvBb 

1967. 

84°37'30'' 

36"37'30'' 

30' 22'30'' 15' 7'3r:J' B3°52'3r:J' 

.. ' .. i >·_>···-

/

\ ,' 

. '( I ., 

0 

-.. J~g~!Y.f!<_'(_ .. 

. , 

I 

TENNESSE~ · . 

36"00'~------------~------------~-------------._----------~ 

EXPLANATION 

12] Area underlain by · · Coal Creek seam 

@[:,J>j Deep mined area 

E2J Strip mined area 

- -- - --- Fault zone 

I 

5 MILES 

I 

5 KILOMETERS 

FIGURE 17.-Areas underlain by, and areas mined out of, the Coal Creek coal bed in northern Tennessee. 
G26 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

major underground mine on the Coal Creek coal is 

the Consolidation Coal Co. mine on Tackett Creek in 

Claiborne County. Less than 20 percent of the total 

Coal Creek surface trace has been surface mined. 

Jellico coal bed.-Approximately 122 m (400 ft) 

above the Coal Creek coal is the Jellico coal (fig. 18). 

The Jellico coal is a medium-grade seam (table 1). 

Recoverable reserves are in Anderson, Campbell, 

Claiborne, Morgan, and Scott Counties. These reserves total approximately 54 million short tons. 

Present deep mining of the Jellico coal is limited 

to a few relatively small mines. However, large old 

deep mines are near Petros, Jellico, and Log Mountain west of Bryson. Many of the surface mines on 

30' 22'30" 15' 

the Jellico seam are near the large old underground 

mines at Petros and Jellico. In addition to these, several strip mines are on the Jellico coal in Scott 

County. Less than 10 percent of the total surface 

trace of the Jellico coal is stripped. 

Indian Bluff Formation.-The Indian Bluff Formation consists of 61 to 143 m (200 to 470 ft) of 

clayey to sandy gray shale and minor amounts of 

siltstone and sandstone. The formation includes the 

strata between the top of the the Jellico coal and 

the top of the Pioneer Sandstone Member, or Jordan 

coal bed where the Pioneer is absent. The Indian 

Bluff Formation is in places divided into members 

by the Seeber Flats (Wilson and others, 1956), 

7'3r:J' 

,.· 

- - ~TIJCK'(. •• -·TENNESSEE 

EXPLANATION 

52'30" 

D Area underlain by Jellico seam 

11$?"1 Deep mined area 

~ Strip mined area 

- - - - - Fault zone 

0 5 MILES 

I I 

0 5 KILOMETERS 

83"45' 

36"00' L---------A--------L-----_..._ ___ __,_ _ _, 

FIGURE 18.-Areas underlain by, and areas mined out of, the Jellico coal bed in northern Tennessee·. 
TENNESSEE G27 

Stockstill (Wilson and others, 1956), and Pioneer 

Sandstones (Glenn, 1925). The sandstones are fine 

to medium grained and lenticular. Thicknesses of 

these sandstones are as much as about 24m (80ft), 

and of the three, the Pioneer Sandstone is the thickest and most widespread. The only coal bed of any 

economic significance within the Indian Bluff Formation is the Joyner seam. 

Graves Gap Formation.-The Graves Gap Formation extends from the top of Pioneer Sandstone 

to the top of the Windrock coal bed. The formation 

consists of 55 to 122 m ( 180 to 400 ft) of clayey to 

sandy gray shale and minor amounts of siltstone and 

sandstone. In places, sandstone beds, named the 

Armes Gap Sandstone and Roach Creek Sandstone 

by Wilson, Jewell, and Luther (1956), are thick 

enough to divide the formation into members. The 

sandstones are generally fine to medium grained and 

lenticular. These sandstone members may be as 

thick as 21-24 m (70 to 80 ft). The Graves Gap Formation contains four economically important coal 

beds, the Jordan, Lower Pioneer, Upper Pioneer, and 

Windrock. 

The Redoalc Mountain Formation.-The Redoak 

Mountain Formation includes the strata between the 

top of the Windrock coal and the top of the Pewee 

coal. The formation consists of 91 to 140 m (300 to 

460 ft) of gray clayey to sandy shale and minor 

amounts of sandstone and siltstone. In places, the 

formation is divided into members by lenticular 

sandstones named the Caryville, Fodderstack, and 

Silvey Gap Sandstones by Wilson, Jewell, and Luther 

(1956). The Silvey Gap and Caryville are as thick as 

20 m (65 ft), but the Fodderstack is thinner and 

locally attains a thickness of 10 m (30 ft). Important coal beds in the Redoak Mountain Formation 

are the Big Mary, Beech Grove, Sharp, Red Ash, 

Walnut Mountain, and Pewee. Of these, the Big 

Mary (fig. 19) and the Pewee (fig. 20) are the most 

widely mined and contain the greatest reserves. 

Big Mary coal bed.-Recoverable reserves of the 

Big Mary coal bed were 101,274,000 short tons in 

1959 (Luther, 1959). The Big Mary seam ranges in 

thickness from 0.30 to 2.59 m ·(1 to 8.5 ft), including shale partings and beds that range generally 

from 0.05 to 1.2 m (0.17 to 4ft). In a few places, the 

Big Mary is split by shale beds as much as 3 m (10 

ft) thick, so that each split is too thin to mine. The 

Big Mary has been extensively strip mined, augered, 

and deep mined in Tennessee (fig. 19). Approximately 20 percent of the Big Mary cropline has been 

strip mined. The most extensively deep-mined areas 

are near Petros, Devonia, Rosedale, Turley, and 

Fork Ridge. The Big Mary seam is a low-grade 

steam coal because of its relatively high sulfur and 

ash contents (table 1). The Tennessee Valley Authority purchases most of the coal mined from the 

Big Mary seam. 

Pewee coal bed.---.:The Pewee coal bed is at the top 

of the Redoak Mountain Formation approximately 

116-122 m (380-400 ft) above the Big Mary coal 

bed. Recoverable reserves of the Pewee seam were 

32,934,000 short tons in 1959 (Luther 1959). Since 

then, an undetermined amount has been mined. The 

Pewee seam ranges in thickness from approximately 

0.3 to 2.1 m (1 to 7 ft) including partings that range 

from 5 to 76 em ( 0.17 to 2.5 ft). At most places the 

coal is solid, or partings aggregate less than 15 em 

(0.5 ft) in thickness. The Pewee has been extensively strip mined, augered, and deep mined in Tennessee (fig. 20). Approximately 35 percent of the 

Pewee cropline has been strip mined. The most extensively deep-mined areas are in the mountains 

surrounding Pewee and in the areas northwest of 

Petros, west of Fork Ridge, and north of Windrock. 

The Pewee is a high-grade steam coal (table 1). 

Vowell Mountain Formation.-The Vowell Mountain Formation includes the 1strata betw·een the top 

of the Pewee coal and the top of the Frozen Head 

Sandstone. The formation ranges from 70 to 128 m 

(230 to 420 ft) in thickness and consists of gray 

clayey to sandy shale and minor siltstone and some.> 

sandstone. A sandstone member in the middle of 

the formation was called the Pilot Mountain Sandstone by Wilson, Jewell, and Luther (1956). Glenn 

(1925) named the Frozen Head Sandstone at the 

top. Like other sandstones in the delta-plain sequence, these sandstones are fine to medium grained, 

are lenticular, and may be as much as 18-20 m (60:.... 

65 ft) thick. The coal beds in the Vowell Mountain 

Formation are the Split, Petree, Lower and Upper 

Pine Bald, and Rock Spring coals. Only the Lower 

Pine Bald coal and the Rock Spring coal have been 

mined, and the Rock Spring is the highest seam in 

Tennessee that has been mined underground on a 

large scale (Luther, 1959, p. 136). Barlow (1969) 

studied the plant fossils of the northern coal field 

and concluded that the Rock Springs coal bed was 

the base of the Allegheny Series in Tennessee. 

Cross Mountain Formation.-The Cross Mountain 

Formation includes strata between the top of the 

Frozen Head Sandstone and the top of Cross Mountain and is 169 m (554 ft) thick at its type section. 

These are the youngest Pennsylvanian beds preserved in Tennessee. The formation is composed of 

sandstone and shale members lithologically similar 
G28 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

D 

~ 

t::J 

EXPLANATION 

Area underlain by Big Mary 

coal seam 

Deep mined area 

Strip mined or strip mined and 

augered area 

5 MILES 1---~-...J 

5 KILOMETERS 

36°00' .__ ______ ..~...._ ______ .,L_ ______ .l._ _____ __J 

FIGURE 19.-Areas underlain by, and areas mined out of, the Big Mary coal bed in northern Tennessee. 

to the strata below. Named sandstone members are 

the Low Gap and Tub Spring Sandstones. They are 

both lenticular and vary grea.tly in thickness ; the 

Low Gap reaches a maximum of 21.3 m (70 ft), and 

the Tub Spring is as much as 15.2 m (50 ft) thick. 

The Cross Mountain contains six named coal seams 

in Tennessee, but only the Upper and Lower Grassy 

Spring coals, the Cold Gap coal, and the Lower Wild 

Cat coal have been mined (Johnson and Luther, 

1972, p. 5) 0 

INDICATORS OF DEPOSITIONAL 

ENVIRONMENTS IN THE UPPER-DELTA-PLAIN 

SEQUENCE 

The sequence reviewed in this section includes the 

upper three (Redoak Mountain, Vowell Mountain, 

and Cross Mountain) of six formations generally 

assigned to the Middle Pennsylvanian in Tennessee. 

The interval, which is about 305 m (1,000 ft) thick, 

was selected for study because it was only recently 

strip mined, and the highwall exposures are largely 
TENNESSEE G29 

84•37'3(1' 30' 

--------- ---------- 22'

3

11' KENTIJCKY 15' --TENNESSEE- - 84•oo· 113"52'3(1' 

3~~· r-------------------------~-------------4--~-o ___ o~·~~~-+------~ 

EXPLANATION 

0 

Wind rock {!;:::: :.j Area underlain by Pewee coal seam 

PSfa Deep mined area 

~ Strip mined, or strip mined and 

~ augered area 

5 MILES 1-----.--.....J 

3~·~--------------------~~----------------~----------------~ 5 KILOMETERS 

FIGURE 20.-Areas underlain by, and areas mined out of, the Pewee coal bed in northern Tennessee. 

unreclaimed. The interval contains a dozen or more 

minable coal seams within the Wartburg basin, but 

only two or three (principally the Big Mary and 

Pewee coals) are laterally continuous and minable 

almost basinwide. 

Figure 21 is a columnar section of the 305-m-

( 1,000-ft-) thick sequence, the width of which is designed to show both the primary lithology, and selected drawings of 50-m- (164-ft-) long sections of 

strip-mine highwalls. The lateral sections depict 

facies relationships seen in highwall exposures near 

the Scott-Anderson County line. The columnar section consists of several sequences that coarsen upward, each of which begins with dark-gray shale 

and fauna indicative of a marine or brackish-water 

incursion. Overlying channel, · levee, and splay deposits reflect the progradation and reestablishment 

of the delta. The extent and duration of each episode is indicated by the thickness and extent of the 

facies. The establishment of a coal swamp signaled 

the end of each progradational phase, at which time 

the river system that maintained the complex was 
G30 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

EXPLANATION 

[~?A) Sandstone 

D Sdtstone 

• Shale 

(:':·:·:::·::·j Layered siderite 

~ Limestone concretion 

' Coarsening upward 

sequence 

' rming upward 

sequence 

A. Fossd tree 

< Marine fossds 

FIGURE 21.-Columnar section of upper Middle Pennsylvanian 

coal-bearing sequence, with drawings of strip-mine highwalls. 

abandoned; then, when subsidence exceeded sedimentation, the delta plain was inundated. 

The stage of delta development . represented by 

the columnar section was principally that of the 

lower delta plain and was characterized by broad 

interdistributary bays and sluggish channels having 

low, barely emergent levees and numerous but localized crevasse splays. Although the sequence is generally one of progradation leading to the ultimate 

establishment of an upper-delta-plain/terrestrial environment, this progradation was intermittent and 

was punctuated by many reversals or lateral shifts 

in environment. The environments represented range 

from shallow-water marine to those of the upper 

delta plain including freshwater swamps and coalesced point-bar deposits. 

The broad areal extent of the Big Mary coal bed 

within the Wart burg basin and the marine zone that 

typically overlies it testify to the abandonment and 

inundation of a widespread delta complex. At least 

seven marine incursions took place within the interval studied. The one that covered the Big Mary coal 

was relatively slow to retreat, as is evidenced by a 

sequence that is 17 m (55 ft) thick of medium- to 

dark-gray clay shale beds that contains a diverse 

marine fauna, rhythmically repetitious thin layers 

of siderite, and several tabular clayey siltstone beds 

interpreted to be delta-front sheet deposits. The 

' marine zone is discontinuous and is. locally absent 

eastward across the basin. This absence suggests 

that the sea invaded from the west (Thomas 

Roberts, oral commun., 1977). A second prominent 

marine zone covers the Upper Grassy Spring coal 

bed, but, because the Grassy Spring coals are confined to only the higher mountain tops, strip mines 

are few and far ·apart, and the· associated marine 

zone is poorly described. Distributary-mouth bar 

sequences were observed in highwalls above both 

the Big Mary (White, 1975) and Upper Grassy 

Spring (top of section-fig. 21) coals. 

When the delta complex grew substantially, channels formed and meandered broadly, forming extensive point-bar deposits such as those in the highwalls above the Pewee coal bed (fig. 21) . Abundant 

fossil remains of large trees are preserved in growth 

position on levees and in interdistribu.tary areas at 

several horizons but are best preserved in the interval overlying the Pewee coal bed. The presence of 

many large trees is interpreted to signify the establishment of a freshwater s;wamp similar in some 

ways to modern cypress swamps. 

SIDERITE 

Siderite is present throughout the entire study 

interval, in both marine and nonmarine beds. The 

nature of siderite occurrences varies within the sequence, however, and is considered useful in interpreting depositional environments. In sequences 

known to be marine by virtue of fossils and facies 

associations, siderite is present in thin (about 5 em, 

2 in.) persistent layers that alternate with the dark-
TENNESSEE G31 

gray silty shales. Above the marine deposits, these 

layers grade into segmented disk-shaped nodular 

masses as the sequence in which they are enclosed 

coarsens and becomes less marine. Occurrences of 

siderite in this layered form are typical both of the 

gray shale sequence overlying the Big Mary coal 

bed and of other marine intervals within the sequence studied. 

The marine formation of siderite was not accepted 

by Berner (1971). He described siderite as a relatively common constituent of ancient nonmarine 

sediments, where it is normally found in association 

with coal beds and freshwater clay. He stated 

further that siderite is not stable in marine sediments and has never been observed forming in 

modern marine sediments. 

Large lens-shaped concretions of siderite or limestone (micrite) as much as 2.4 m (8 ft) in diameter 

and 1 m (3.3 ft) in width are found within the 

marine to brackish intervals, especially above the 

Big Mary coal, but the concretions are not everywhere associated with layered siderites. That these 

concretions, called "flying saucers" by the miners, 

are clearly diagenetic is indicated by the fact that 

thin laminae of the enclosing shale pass undisturbed 

into the carbonate masses. Subsequent compaction 

caused draping of layers immediately above and beneath the concretions. 

Where trees are preserved in growth position in 

carbonaceous shale of terrestrial origin, siderite is 

present in large irregularly shaped masses, some of 

boulder proportions. Unlike the conformable diskshaped masses in the marine intervals, the irregularly shaped masses cut across the bedding as did 

the roots of ancient trees around which they nucleated. Less commonly, siderite masses filled in and 

preserved the trees themselves. Siderite masses of 

the irregularly shaped variety are most abundant 

where fossil trees are large and numerous; hence, 

they are believed to be useful in recognizing freshwater-swamp and upper-delta-plain environments. 

Both nonmarine and marine siderite deposits are 

believed to have lithified quickly, whether they precipitated chemically as a primary sediment or 

formed diagenetically. As channels moved and the 

shales and their interbedded siderite layers were 

scoured, the lithified siderite formed large clasts in 

channel lag deposits. 

FOSSIL TREES 

Studies of the fossil trees preserved in growth 

position in the area around the Wart burg basin have 

provided a new understanding of depositional environments and rates of sedimentation. The transition from a lower-delta plain to an upper-delta plain 

environment is marked by a gradual change in flora. 

Following widespread marine incursions, such as 

the one that terminated the Big Mary coal swamp, 

the delta complex from lower to upper delta plain 

was slowly reestablished. 

The lower delta plain is characterized by thin and 

areally restricted levees, splays, and bar deposits 

devoid of plants preserved in life position. Coincident with the growth in size and extent of the levees 

and splays is the appearance of .the tree, Calamites. 

Because of the early appearance of Calamites in the 

reestablishment and progradation o.f the delta, 

Calamites is thought to have been more salinity 

tolerant than the larger Lepidodendron and Sigillaria found ·preserved in growth positions higher in 

the sequence and hence higher on the delta plain. 

Probably Calamites first became established on low, 

barely subaerial levees where pore waters were 

fresh to brackish but where salinity varied widely 

seasonally if ·not diurnally. Because Calamites had 

a wide range of salinity tolerance, it persisted on 

the delta plain in freshwater environments. 

Upward in the section and in assoc·iation with 

larger and coar.ser levee, splay, and point-bar deposits, the larger Lepidodendron and Sigillaria appear and become abundant. These larger trees probably had a low salinity tolerance and grew only in 

freshwater environments. The trees became established first on levees on the lower delta plain where 

pore waters were fresh; they spread onto the up.per 

delta pla·in and into the freshwater :interdistributary 

areas, became more abundant, and formed swamps. 

The presence of Calamites among Lepidodendron 

and Sigillaria indicates that the environments .in 

which Calamites flourished included freshwater environments. Sigillaria and Lepidodendron are particularly abundant in the interval immediately overlying the Pewee coal. 

In strip-mine highwalls, the sequence observed 

consists of interbedded, interdistributary silty gray 

shale and undulating distal levee or flood deposits. 

Fossil trees 1 m (3.3 ft) or more in diameter have 

roots in the gray shale, indicating that the trees 

grew in a shallow-water, highly carbonaceous swamp 

environment. The undulating fine sandstone and siltstone layers represent flood deposits, which periodically covered the swamps and buried the trees to 

depths of 0.5 m (1.6 ft) or more. Burial to such 

depths kills most modern trees, but these ancient 

trees were capable of generating n·ew roots at the 

new sediment-water interface (fig. 22). 
G32 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

----- -- S-H-A-r-E --- • rl. .L:\.r.LJ_ -

FIGURE 22.-Tree, showing generation of new roots at a higher sediment-water interface that formed when the base was 

buried by a flood deposit. 

In several deposits, the base of a fossil tree i.s surrounded by a planar-convex body of sandstone as 

shown in figure 23. The sand collected in a depression produced by compaction of the swamp-floor 

mud by the increasing weight of the growing trees. 

During floods, the depressions around the bases of 

trees were filled with the coarser sediment carried 

by the moving water. Within the planar-convex 

bodies, numerous carbonaceous partings contain 

roots and conform to the curvature of the lower 

convex boundary of the sand body, indicating that 

tree growth, compaction, sand deposition, and the 

generation of new roots at each successive sedimentwater interface were all parts of a gradual continuing process. 

Figure 24 shows a tree that was buried to a depth 

of 4.6 m (15ft). Because the tree is in growth position and shows no root regeneration, it probably was 

buried very quickly, certainly before it could decay. 

Probably the tree (and others like it) grew in a 

back swamp, the level of which was substantially 

below the water level of the adjacent levee-confined 

river. When crevasses formed in the natural levee, 

sediment-laden waters rushed into the back swamp, 

their velocity was quickly checked, and deposits 

were immediately laid down around the trees. Thus, 

a tree, rooted in mud, could be buried by 4.6 m (15 

ft) of sediment without being knocked over by the 

transporting current. Minkin (1977) described several trees that were bent over, all at the same level 

and in the same direction during burial by such a 

flow. Moving sediment and water apparently continued to push against the upper parts of the trees 

after the lower parts of the trees had been buried 

and stabilized. 

HEAVY METALS AND SULFUR 

Franks (1976) and Thompson (1977) conducted 

studies of the heavy-metal content and associations 

of several depositional facies in the hope that these 
TENNESSEE 

·/ 

.. .. ~ ----- ~ 

FIGURE 23.-Planar-convex sand bodies at the base of a fossil tree. 

G33 
G34 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

FIGURE 24.-Lepidodendron buried in growth position by 

shaly deposits to a depth of 4.6 m (15 ft) . 

would provide criteria for distinguishing marine 

from nonmarine sediments or marsh deposits from 

swamp deposits. The two studies focused on the Big 

Mary and Pewee coals and the sedimentary rocks, 

exposed above them in strip-mine highwalls. The Big 

Mary ~as selected because it is overlain by a marine 

sequence and the Pewee because it is overlain by 

freshwater swamp deposits. The elements investigated were As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and 

Rb. 

The studies were inconclusive about the value of 

these elements as environmental indicators. However, the studies did show that the concentration of 

heavy metals is primarily a function of grain size. 

Concentrations are high in the shale, particularly 

in the shale immediately overlying coal beds, but 

are relatively low in the coarser deposits. The coal 

beds themselves have low concentrations of the 

heavy metals. 

The coal in the Middle Pennsylvanian sequence is 

typically high in sulfur and ash. In places, the Big 

Mary coal contains 2.8 percent sulfur and 9.5 percent ash, and the Pewee coal contains 1.1 percent 

sulfur and 10.9 percent ash (Garman and Jones, 

1975). The ash content reflects proximity to a 

source of detrital sediment during peat accumulation, whereas sulfur content relates in some degree 

to the position on the delta-plain complex where the 

coal formed. The high sulfur content of the Big 

Mary supports the inference that it was formed on 

the lower delta plain in association with brackish or 

marine water. The moderate sulfur content of the 

Pewee coal supports the interpretation that it was 

deposited higher on the delta plain in association 

with fresh water in a depositional environment 

similar to that of the Eocene Wilcox lignite of 

Texas (Kaiser, 1974). The high sulfur and heavymetal concentrations in these and other Middle 

Pennsylvanian coals indicate that the Tennessee 

area, like the area in West Virginia described by 

Horne and others 1 (1977), was slow to subside. 

MISSISSIPPIAN OIL AND GAS FIELDS IN THE 

NORTHERN CUMBERLAND PLATEAU 

Most of Tennessee's oil production has come from 

carbonate reservoirs of Mississippian age in Scott 

and Morgan Counties. Since 1969, more than 90 percent of the State's oil production has come from 

Fort Payne reservoirs found in these two counties. 

Although oil and gas production in this area dates 

from the early 1900's, the discovery of the Oneida 

West Fort Payne pool in 1969 initiated an active 

shallow play which is still continuing. Although the 

primary objective is limestone of the Fort Payne 

Formation, smaller oil and gas pools are in the 

Monteagle, Bangor, and Warsaw limestones and the 

Hartselle sandstone. To date, no significant discoveries have been made in the Pennsylvanian rocks, 

although several small oil wells and shut-in gas wells 

have been completed in Lower Pennsylvanian sandstone in Scott County. 

Figure 25 shows the locations of the more important Fort Payne and Monteagle pools in Scott, 

northern Morgan, and eastern Fentress Counties. 

Table 2 lists selected pools, discovery dates, number 

1 H orn e, J. C., Ferm, J. C., Caruccio, F . T., Cohen, A. D. , Baganz, 

B. P ., Cantrell , C. L ., Corvinus, D. A., Geidel, G., H owell, D. J. , Math ew, 

D., Melton, R. A. , P edlow, G. W ., Sewel, J . M., a n d Staub, J. R., 1977, 

Depositional models in coal exploration a nd mine p la nning, unp ublish ed 

ma n uscript on fi le w it h ( 1 ) T ennessee D iv. Geology, Knoxville, T enn., a n d 

( 2) Carobna Coal Gr ou p , Dept. Geology, U niv. Sou t h Ca r olina, Columbia, 

S.C. 
TENNESSEE G35 

36" 

30' 

EXPLANATION 

Q Fort Payne Formation D Monteagle Limestone 'lJ Gas " Oil 

0 

I 

0 

I 

10 

10 MILES 

I I 

15 KILOMETERS 

FIGURE 25.-Mississippian oil and gas pools in the northern Cumberland Plateau. Dashed line encloses a group of oil pools. 

Fort Payne production: 1. Oneida West, 2. Honey Creek So., 3. Gum Branch, 4. Indian Creek, 5. Burrville, 6. Boone 

Camp (abandoned), 7. Lick Branch unit, 8. Low Gap, 9, Reuben Hollow, 10. Hurricane Ridge. Monteagle production: 

11. Glenmary, 12. Sunbright, 13. Union Hill, 14. Li.ttle Clear Creek, 15. Douglas Branch, 16. Shirley, 17. Big Branch, 

18. Grimsley North, 19. Hurricane Creek, 20. Coal Hill. 

of producing wells, and cumulative oil production. 

Fort Payne reservoirs have produced nearly 4 million bbl of oil in Scott and ·Morgan Counties, 3.8 

million bbl since 1969. Data on gas-pool production 

are omitted from table 4 because production to date 

has been quite limited. Owing to lack of pipeline 

facilities, many of the gas wells in the trend are 

currently shut-in. 

As presently known, the area of productive Fort 

Payne is about 32 km (20 mi) long, is 13-19 km 

(8-12 mi) wide, and trends northeast from Burrville 

in Morgan County to Oneida in Scott County. No 

major structural features are present in the area, 

which is west of the Pine Mountain fault block and 

north of the Cumberland Plateau overthrust. Regional dip is about 7.6 m/km (40 ft/mi) to the 

southeast. Mapping of the subsurface reveals only 

minor structural warping. Available data indicate 

that most Mississippian reservoirs are primarily 

stratigraphic traps having little or no relationship 

to observed structure. 

Fort Payne reservoirs consist of one or more 

zones of vugular porosity found within local lenses 

or mounds of fossiliferous and fragmental limestone 
G36 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

TABLE 2.-List of selected Mississippian oil and gas pools, Tennessee 

Number 

in figure 

25 Field name, County Year of discovery 

Number of Cumulative production producing to December 1977 (bbl) wells 

Fort Payne Pools 

6 __________________ Boone Camp, Morgan 1924 13 150,000 est. 

l_ __ --- ______ --- ___ Oneida West, Scott 1969 40 1,215,687 

(Off fig. 25) Broken Leg, Overton 1970 10 43,699 

2 __________________ Honey Creek So., Scott 1972 15 239,586 

3 __________________ Gum Branch, Scott 1973 6 71,509 

4 __________________ Indian Creek, Morgan 1973 35 1,312,102 

5_ ----- ____________ Burrville, Morgan 1974 39 321,700 

7 __________________ Lick Branch Unit, Scott 1976 26 463,968 

8 __________________ Low Gap, Scott 1976 18 . 100,863 

9 __________________ Reuben Hollow, Scott 1977 10 37,456 

Monteagle Pools 

1L _________________ Glenmary, Scott 

14 __________________ Little Clear Creek, Morgan 

20 __________________ Coal Hill, Scott 

15 __________________ Douglas Branch, Morgan 

1 Abandoned. 

that overlie the typical massive chert and siliceous 

carbonate rocks of the lower Fort Payne. These 

lenses are generally tabular or elongate, locally are 

as thick as 24 m (80 ft), and range in areal extent 

from 80-120 ha (200-300 acres) to 7-10 km2 (3-4 

mi 2 ). Studies of samples indicate that these lenses 

contain little or no chert and are in sharp contact 

with the underlying cherty carbonate. They are 

overlain by dark-gray, impermeable, dolomitic siltstones (upper part of the Fort Payne and lower part 

of the Warsaw) which serve as seals for the reservoirs. Structural mapping indicates that a surface 

of considerable relief is on the top of the cherty 

carbonates even within the limits of a single pool. 

Previous studies (Statler, 1971, 1975) suggest that 

the thickness and configuration of the cherty carbonate in the lower part o.f the Fort Payne may have 

an important bearing on the location and geometry 

of the productive limestone lenses. 

Younger Mississippian oil and gas fields have 

been found in a wider area extending into western 

Fentress County, and several small fields have been 

found along the eastern edge of the Cumberland 

Plateau in Anderson and eastern Morgan Counties. 

The most important of these fields are in the Monteagle Limestone, which locally has good porosity 

and permeability in the massive oolitic and bioclastic limestone facies. Most of the Monteagle discoveries are gas reservoirs; they are apparently 

mainly stratigraphic traps, although structural 

warping may contribute fracture porosity locally. 

1916 20 206,500 est. 

1928 4 79,050 

1950 1 38,567 

1972 12 47,288 

The fact that several gas-gathering systems are currently being constructed in the area should greatly 

stimulate interest in and drilling for these shallower 

gas reservoirs. 

Outside of the area shown in figure 25, the Cumberland Plateau is only sparsely drilled. Although 

widely scattered wildcats in the southern and eastern parts of the plateau have not yet found commercial quantities of oil or gas, large areas remain 

virtually untested. Mississippian lithologies and 

drilling depths are comparable to those of the producing area in the northern plateau. 

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TENNESSEE G37 

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G38 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

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Wilson, R. L., in press, Geologic map of the Oolte.wah quadrangle, Tennessee: Tennessee Div. Geology Geol. Map 

GM 112-SE, scale 1 :24,000. 
The Mississippian and Pennsylvanian 

(Carboniferous) Systems in the Unite_d StatesGeorgia 

By WILLIAM A. THOMAS and HOWARD R. CRAMER 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1110-H 

Prepared in cooperation with the Georgia 

Department of Natural ResourcesJ 

Geologic and Water Resources Division 

Historical review and summary of arealJ stratigraphicJ 

structuralJ and economic geology of Mississippian 

and Pennsylvanian rocks in Georgia 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1979 

CONTENTS 

Albstract -----------------------------------------------------------------

Introduction ------------------------------------------------------------- History of the study of the Carboniferous rocks ----------------------------

Distribution and structural setting of the Carboniferous rocks ---------------

Mississippian stratigraphy of northwest Georgia, by Willaim AL. Thomas ------

Lithofacies ---------------------------------------------------------- Evolution of stratigraphic nomenclature --------------------------------

Lithostratigraphy ___________________ ---------------------------------

Maury Shale -----------------------------------------------------

Fort Payne Chert ------------------------------------------------

Tuscumbia Limestone ---------------------------------------------

Monteagle-Bangor Limestones --------------------------------------

Pennington Formation and Raccoon Mountain Formation above northwestern carbonate facies ---------------------------------------- Lavender Shale Member of Fort Payne Chert ----------------------

Unnamed lower limestone of clastic facies --------------------------

Floyd Shale ------------------------------------------------------ Unnamed sandstone at top of Floyd Shale --------------------------

Bangor Limestone tongue of southeastern clastic facies --------------

Pennington Formation of. southeastern clastic facies ----------------

Raccoon Mountain Formation of southeastern clastic facies ----------

Possible facies transition -----------------------------------------

Paleontology ---------------------------------------------------------

Biostratigraphy -------------------------------------------------- Paleoecology _______________________________________ ---- _________ _ 

Depositional and tectonic framework ----------------------------------

Pennsylvanian stratigraphy of northwest Georgia, by Howard R. Cramer ----

Lithofacies ---------------------------------------------------------- Evolution of stratigraphic nomenclature -------------------------------- Lithostratigraphy ______________________________________ ----- ________ _ 

Pennsylvanian rocks on Sand Mountain, Catoosa County ------------

Pennsylvanian rocks on Little Sand Mountain, Chattooga County ------

Pennsylvanian rocks on Rocky [Rock] Mountain, Floyd County ------

Pennsylvanian rocks on Pigeon Mountain and on the southern part of 

Lookout Mountain, Chattooga, Dade, and Walker Counties --------

Pennsylvanian rocks on the northern part of Lookout Mountain, Dade 

and Walker Counties -------------------------------------------

Pennsylvanian rocks on Fox Mountain, Dade County -----------------

Pennsylvanian rocks on Sand Mountain, Dade County ----------------

Correlation of Pennsylvanian rocks --------------------------------

Biostratigraphy ----------------------------------------~------------­ Depositional and tectonic framework -----------------------------------

Past interpretations ----------------------------------------------

Current interpretations ------------------------------------------- Mississippian-Pennsylvanian boundary problem -----------------------------

Mineral resources of the Carboniferous rocks ------------------------------

Coal -------------------~-------------------------------------------­ Clay and shale ------------------------------------------------------- Building stone ____________ -------------------------------------------

Limestone and dolostone ----------------------------------------------

Chert ---------------------------------------------------------------

Slate ---------------------------------------------------------------- Ground water 

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IV CONTENTS 

Paae 

Scenjc features ----------------------------------------------------------- 1-134 

References cited ---------------------------------------------------------- 34 

ILLUSTRATIONS 

Page 

FIGURE 1. Index map of Georgia --------------------------------------------------------------------------- 1-11 

2. Correlation chart showing the evolution of Carboniferous nomenclature in Georgia -------------------- 3 

3 . .,Geologic map o~ northwest Georgia and outline map showing localities mentioned in text -------------- 4 

4. Diagrammatic stratigraphic cross sections of Mississippian rocks in northwest Georgia -------------- 6 

5. Chart showing the evolution of stratigraphic subdivision and nomenclature of Mississippian rocks in 

northwest Ge:orgia ____________________________ -·-- ____________ ---- ______ --- _ ------- _____ ----- 7 

6. Chart showing microfacies of Mississip.pian carbonate rocks in Georgia ------------------------------ 10 

7. Chart showing marine benthic communities in the Floyd Shale ------------------------------------- 16 

8. Generalized lithofacies and paleogeographic maps of Mississippian rocks in northwest Georgia -------- 17 

9. Generalized columnar sections showing Pennsylvanian and Mississippian rocks above the Bangor Limestone 19 

10. Correlation chart showing evolution of Pennsylvanian nomenclature in Georgia ----------------------- 21 

11. Hypothetical stratigraphic cross section of rocks 'near the Mississippian-Pennsylvanian boundary in northwest Georgia ------------------------------------------------------------------------------- 31 

12. Graph showing coal production in Georgia for 5-year intervals from 1860 to 1977 -------------------- 32 

TABLE 1. 

2. 

TABLES 

Page 

Coal reserves, Georgia, 1907-74 -------------------------------------------------------------------- H32 

Proximate analyses and sulfur content of Georgia coals ---------------------------------------------- 33 
THE MISSISSIPPIAN AND PENNSYLVANIAN (CARBONIFEROUS) 

SYSTEMS IN THE UNITED STATES-GEORGIA 

By WILLIAM A. THOMAS1 and HowARD R. CRAMER2 

ABSTRACT 

Mississippian and Pennsylvanian rocks are exposed in the 

Appalachian fold and thrust belt of northwest Georgia. The 

Mississippian System includes a carbonate facies on the 

northwest and a clastic facies on the southeast. The carbonate facies is characterized by high-energy shallow-marine 

limestones. The clastic facies is composed mainly of prodelta 

mud and includes minor delta-front sands. Intertonguing of 

the clastic and carbonate facies indicates that delta progradation alternated with transgression and delta destruction. 

Both facies of the Mississippian System grade upward 

through a sequence of fine clastic rocks to massive sandstone that has commonly been considered as Pennsylvanian. 

However, the Mississippian-Pennsylvanian boundary is not 

precisely defined. Early Pennsylvanian rocks (Pottsville) are 

the youngest Paleozoic· rocks in northwest Georgia. The 

Pennsylvanian System is predominantly sandstone and shale, 

and contains subordinate amounts of conglomerate, coal, 

and siltstone. The lower coal-bearing rocks appear to have 

been deposited in a shoreline environment; bar, tidal-delta, 

and lagoonal deposits have been identified. The upper coalbearing rocks appear to have been deposited in a lower-deltaplain environment; the sedimentary units are individually 

more widespread and less variable·. Bituminous coal is the 

major economic resource, although the reserves are uncertain 

and may be somewhat less than 100 million tons. All the 

coal is medium- and low-volatile, low sulfur, and for the most 

part in beds much less than 1 m thick. 

INTRODUCTION 

Sedimentary rocks· of the Mississippian and Pennsylvanian Systems are exposed in the Appalachian 

fold and thrust belt of northwest Georgia (fig. 1). 

The maximum thicknes~s is more than 1,000 m. The 

Mississippian System includes a carbonate facies on 

the northwest and a clastic facies on the southea·st. 

Both facies of the Mississippian System grade upward into a Pennsylvanian clastic sequence characterized by ~andstone, shale, and coal. 

In the Appalachian Piedmont o.f Georgia (fig. 1), 

som.e metamorphic and plutonic rocks yield radiometric dates indicating a Mississippian-Pennsylvanian age (Pinson and others, 1957; Smith and 

1 Dcpa•rtmcnt of Geology, Georgia State University, Atlanta, Ga. 3()!30·3. 2 Department CJf Geology, Emory University, Atlanta, Ga. ~0·322. 

others, 1969; Hurst, 1970; Fullagar, 1971; Fullaga.r 

and Butler, 1974; Jones and others, 1974; Whitney 

and others, 1976). None of the metas•edimentary 

rocks in the Appalachian Piedmont of Geo·rgia has 

yet been shown to represent Mississippian-Pennsylvanian deposition. To the southwest, in the Piedmont of Alabama, metasedimentary rocks in the 

Talladega Slate belt include sedimenta.ry deposits 

of Mississippian (Carrington, 1967, p. 26) and 

Pennsylvanian ages (Butts, 1926, p·. 219). Parts of 

the Talladega have been traced from Alabama into 

northwest Georgia (Cressler, 1970, p. 51). 

£!!!::::: 

·::::::: 

········ ········ ······· ······· 

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EXPlANATION 

IITiillJ Appalachian fold &nd 

thrust belt 

FIGURE 1.-Index map of Georgia. 

Hl 
H2 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

In south Georgia, beneath the Mesozoic-Cenozoic 

strata of the Gulf Coastal Plain, the Suwannee basin 

contains a thick sequence of Paleozoic clastic sedimentary rocks (fig. 1). Palynological studies of 

samples from one well (Anderson No. 1 Great 

Northern Paper Co.) indicate a Devonian age 

(McLaughlin, 1970). Studies of fossils in cores 

from another well (Warren No. 1 Chandler) yield 

conflicting results. Ostracodes suggest a Late Ordovician or Early Silurian age (Swartz, 1949, p. 320) ; 

however, Pennsylvanian pelecyp:ods have been 

identified in slightly deeper beds. (Palmer, 1970). 

Possibly Mississippian-Pennsylvanian strata will be 

documented by future work in the pre-Mesozoic 

basin. 

The purpose of this paper is to review the Mississippian and Pennsylvanian sedimentary rocks in 

Georgia as they are presently understood. The scope 

of the paper is limited to c.onsideration of known 

Mississippian-Pennsylvanian strata in the Appalachian fold and thrust belt of northwest Georgia. To 

facilitate organization, a twofold subdivision has 

been used; however, that ·subdivision is hampered 

by problems of identification of the MississippianPennsylvanian boundary. In general, Thom.as has 

gathered and interpreted data relative to Mississippian rocks, and Cramer has gathered and interpreted 

data relative to Pennsylvanian rocks. The Mississippian limestone is a distinct lithostratigraphic entity, 

but the overlying :sequence of shales and sandstones evidently lacks persistent lithostratigraphic 

markers. Massive sandstone above the base of the 

shale-sandstone sequence forms a bluff that is topographically distinct; however, the bluff \evidently 

is formed by different sandstone units at different 

places. In any local stratigraphic column, the top 

of the limestone and a bluff-forming sandstone are 

the most readily identified beds. In the following 

discussions, these beds are used loosely as reference 

horizons. Available biostratigraphic data suggest 

that the Mississippian-Pennsylvanian boundary is 

probably within the shale-sandstone ·sequence between the top of the limestone and the massive 

sandstone but may be as hjgh as so·me of the massive sandstones. 

The discus,sion and interpretations are based on 

data from publications, unpublished manuscripts, 

field notes, and core descriptions available for compilation in 1977. We acknowledge the assistance of 

many geologists in identifying data sources. Cores 

from the Rocky Mountain area, Floyd County, were 

described by H. D. Lowe and G. S. Grainger of the 

Southern Co. ; data from cores and outcrop•s were 

provided by G. S. Grainger and W. V. Conn of 

Georgia Power Co. Cores from Pigeon and Lookout 

Mountains, Walker and Chattooga Counties, were 

described by Duane Jorgensen of the United States 

Gypsum Co. Core descriptions and measured secti.on data were provided by Robert Bolding o.f West 

Georgia College, R. C. Milici of the Tennessee Division of Geology, B. J. Timmons of Florida Rock Industries, D. H. White, Jr., of the U.S. Bureau o.f 

Mines, and R. L. Wilson of the University of Tennessee at ·chattanooga. Access to file data of the 

Georgia Geological Survey was. provided by S. M. 

Pickering, Jr., .and J. B. Murray. The manuscript 

has been read by J. B. Murray, D. E. Ogren, S. M. 

Pickering, Jr., Mark Rich, J. A. Waters, and E. L. 

Yochelson, and we apop-reciate their comments. 

The stratigraphic nomenclature used in this paper 

has not been reviewed by the Geologic Names Committee of the U.S. Geological Survey. The nomenclature used here conforms with the current usage 

of the Georgia Department of Natural Resources, 

Geologic and Water Resources Divi:sion. 

HISTORY OF THE STUDY OF THE 

CARBONIFEROUS ROCKS 

Figure 2 shows the evolution of the classification 

schemes that have been used for the Carboniferous 

rocks of Georgia. 

The period from 1809 to 1892 includes that time 

from when geology was first studied in the United 

States to when the Carboniferous rocks of Georgia 

were first investigated. During this· period, the 

Carboniferous rocks of Georgia were examined only 

incidentally, as parts of larger regional studies. The 

nomenclature used did not originate in Georgia but 

was introduced from elsewhere. Williams (1891) 

provided a history of the nomenclature evolution of 

the Carboniferous rocks of Georgia and elsewhere. 

The period from 1892 to 1904 encomnas·ses the 

time when geologists, mostly .from the U.S. Geological Survey, first investigated the rocks of Georgia 

and proposed names for the subdivisions. The period 

begins with the works of Hayes (1892; 1894; 1895; 

1902) and ends with the summary work on the Carboniferous of the entire Appalachian chain by 

Stevenson (1903, 1904). Economic studies of the 

Carboniferous rocks of Georgia were made by 

Spencer (1893) and McCallie (1904). Many of the 

stratigraphic concepts developed during this period 

are in use today. 

Between 1904 and 1942, little new information 

accrued about the Carboniferous of Georgia except 

that in individual reports on economic geology. In 
· GEORGIA H3 

CARBONIFEROUS ROCKS 

Secondary 

Transition 

Appalachian Coal Field 

Carboniferous 

Carbonlflere lnferlere ou Carbonifiere Superieur ou 

Calcalre du Montagne Terrain Houiller 

Vespertine U~bnil Sera I 

Carboniferous 

Carboniferous 

Sub Carboniferous Coal Measures 

Lower Sub Upper Sub Carboniferous Carboniferous Carboniferous 

Carboniferous 

Fort Floyd Mountain Payne Shale Limestone Coal Measures 

Chert 

Waverlyan Tennesseean Pennsylvanian 

Carboniferous (on map) 

Mississippian (in legend) Pennsylvanian (in legend) 

Mississippian Pennsylvanian 

Tournais- StephanI an Visean Namurian Westphalian ian 

AUTHOR AND 

DATE 

U.S. Map 

Maclure 1809 

Ga. State Map 

Williams, in White 

1849 

U.S. Map 

Marcou 1853 

Rogers 1858 

U.S. Map 

Hitchcock and Blake 

1874 

Ga. State Map 

Little 1876 

U.S. Census Map 

McCutcheon 1884 

Ga .. State Map 

Spencer 1893 

Ulrich 1911 

Ga. State Map 

.Georgia Div. 

Mines, Mining, and 

Geology 1939 

Ga. State Map 

Georgia Geological 

Survey 1976 

European Stages 

FIGURE 2.-Correlation chart showing the evolution of Carboniferous nomenclature in Georgia. 

1939, the first modern geologic map of the State was 

published (Geo-rgia Div. Mines, Mining, and Geology, 

1939) ; this map included a summa.ry of the Carboniferous stratigraphy to that date. 

During, and just after the war years, from 1940 

to about 1950, the need for mineral-resource development prompted geologists again to investigate 

the Carboniferous rocks of Georgia. Most of the resulting reports deal with the coal resources. The 

summary volume of Pennsylvanian stratigraphy of 

the southern Appalachians (Wanles'S, 1946) appeared S~t this time, and also the volume o.f the 

geology of northwest Georgia (Butts. and Gildersleeve, 1948). Correlation charts prepared by committees of the Geological Society of America (Mississippian, Weller, chairman, 1948; Pennsylvanian, 

Moore, chairman, 1944) fixed the nomenclature of 

the Carboniferous of Georgia in relation to that of 

other States. 

Afte.r 1950, geological education in Georgia 

flourished, and much data about the Carboniferous 

resulted from student research. Authors of theses 

mainly used the nomenclature recommended by 

Butts (in Butts and Gildersleeve 1948). 

Expanded activity in geological mapping took 

place between 1960 and 1969, and much detail was 

uncovered by geologists. from the U.S. Geological 

Survey and the Georgia Geological Survey (Cressler, 

1963; 1964a, b; 1970; Croft, 1964). The work of 

Culbertson (1963) summarized the nomenclature 

of the Pennsylvanian rocks. The concepts of regional 

stratigraphic analysis emanating from the Northwestern University school of stratigraphy were applied to Georgia (Stearns and Mitchum, 1962). In 

thi'S report the Pennsylvanian rocks of Georgia are 

shown on three-dimensional map'S in a regional 

context. 

Work by Hobday (1969) initiated another era of 

stratigraphic studies in the Carboniferous rocks o.f 

Georgia. Before this, Ferm and his associates ( Ferm 

and others, 1967; Ferm, 1974) had begun to look 

at the Carboniferous rocks of the Appalachian 

region, not as layers as in a cake, but as a sequence 

of laterally discontinuous, time-transgressive sedimentary units that are a result of changing environments in the coastal, littoral, and deltaic regimes. 

The work of Hobday (1974) was the first published 

account of the Carboniferous rocks of Georgia that 

used such a sedimentologic model as the· primary 

interpretation. Application of this kind of interpretation will require a reevaluation of all of the clastic 

rocks of the Carboniferous of Georgia. 

The U.S. Geological Survey's paleotectonic study 

of the Pennsylvanian of the United States (McK~ 

and others, 1975) summarizes all the available data. 

This and the most recently published geologic map 

of the State (Georgia Geological Survey, 1976) will 

serve as springboards for the reevaluation and future interpretations. 

DISTRffiUTION AND STRUCTURAL SETTING 

OF THE CARBONIFEROUS ROCKS 

Mississippian and Pennsylvanian strata in northwest Georgia are within the Appalachian fold and 

thrust belt (figs. 1, 3A). Pennsylvanian strata, the 
H4 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

----y---

~ I 

( \ 

I 

/ BARTOW 

E ; ; ; : J Pennsylvanian 

A liiiiHWI Mississippian 8 

D Pre-Mississippian 

FIGURE 3.-Geologic map (A) of northwest Georgia and outline map (B) showing localities mentioned in text. Geologic map 

adapted from the g-eologic map of Georgia (Georgia Geological Survey, 1976). 

youngest rocks exposed in northwest Georgia, cap 

flat-topped mountains. The Pennsylvanian beds are 

preserved in the troughs of synclines and commonly 

have gentle dips. Mississippian rocks are exposed 

along the mountain slopes and in adjacent valleys .. 

On the east and south, the Appalachian fold and 

thrust belt is bordered by metamorphic rocks o.f the 

Appalachian Piedmont along the Cartersville (Great 

Smoky) fault. The next major structure northwest 

of the Cartersville fault is the Rome fault, the 

sinuous trace of which reflects low dip and folding 

of the fault plane (fig. 3A). The Rome fault block is 

internally complicated by folds. and faults and is 

composed of lower Paleozoic formations except for 

small areas of Mississippian rocks north of the 

Cartersville fault in Polk County. A regional structural recess in the Appalachian structural system in 

northwest Georgia is expressed by abrupt curves 

in strike of both the Cartersville and Rome faults. 

Northwest of the Rome fault is the large, complex Floyd synclinorium which plunges into a depression northwest of Rome in Floyd County (fig. 

3B). North of the depression, a complex southplunging anticline divides the synclinorium into two 

branches; a thrust fault along the west limb of the 

anticline ends ·southward down the plunge. Southwest of the depression, northeast-trending anticlines 

plunge northeastward. An abrupt change in strike 

within the synclinorium at the depression outlines 

the regional structural recess (fig. 3A). Much of the 

surface area of the depression and synclinal 

branches of the Floyd synclinorium is formed on 

Mississippian rocks. Pennsylvanian rocks in synclinal troughs cap three isolated mountains: Rocky 

Mountain (shown as Rock Mountain on the 71/2-min 

quadrangle map named for the mountain), northwest of Rome; Little Sand Mountain, north of 

Rome; and Sand Mountain3 , east of Ringgold (fig. 

3B). 

Northwest of the Floyd synclinorium on the 

Peavine anticlinorium, Cambrian and Ordovician 

3 Two separate topographic features in northwest Georgia are called 

Sand Mountain: (1) on the east, an &really small mountain east of Ringll'Old in Catoosa County, and (2) in the northwest corner of Georgia, in 

Dade County, a broad flat-topped mountain that extends into Alabama 

and Tennessee. 
GEORGIA H5 

rocks are expo·sed, and the anticlinorium separates 

Mississippian-Pennsylvanian outcrops of northwest 

Georgia into two major parts (fig. 3A). On the 

southeast is the large outcrop· area in the Floyd 

synclinorium. On the northwest is a large area of 

Mississippian and Pennsylvanian outcrops on 

Pigeon, Lookout, and Sand Mountains. 

Northwest of the Peavine anticlinorium, the strata 

are broadly folded in the Pigeon Mountain and 

Lookout synclines (fig. 3A) . The two synclines. are 

separated by the southwest-plunging McLemore 

Cove anticline. The anticline flattens down plunge, 

and the Pigeon Mountain and Lookout synclines apparently m.erge southwestward into the more narrow Lookout ·syncline along Lookout Mountain in 

Alabama. The no·rthwest limb of the Lookout syncline is formed by the en echP.Jon Wills Valley and 

Lookout Valley anticlines (fig. 3A). Northwest of 

the en echelon anticlines, the broad flat-bottomed 

Sand Mountain syncline extends northwestward beyond the northwest corner of Georgia. The most 

northwesterly Appalachian anticline, the Sequatchie 

anticline, is farther northwest in Tennessee and 

Alabama. 

Pennsylvanian rocks form a wide outcrop area 

on the flat mountain tops in the Pigeon Mountain 

and Lookout synclines. A continuous outcrop extends from the northern end of Lookout Mountain 

at Chattanooga, Tenn., acros·s northwest Georgia, 

and southwestward into Alabama. Lo·w·er Pennsylvanian sandstones form a p·rominent bluff, or brow, 

around the top of Pigeon and Lookout Mountains. 

Mississippian formations, mainly lim.estones, are exposed along the slopes of Lookout and Pigeon Mountains. A •similar arrangement of outcrops and rock 

types is found on Sand Mountain in the northwest 

corner of Georgia (fig. 3B). 

MISSISSIPPIAN STRATIGRAPHY OF 

NORTHWEST GEORGIA 

BY WILLIAM A. THOMAS 

LITHOFACIES 

The Mississippian System of northwest Georgia 

includes two geographically and stratigraphically 

distinct facies. The facies on the northwest i1s mainly carbonate rock, and that to the southeast is mainly clastic rock (fig. 4). Areas of distribution of the 

two facies are divided. roughly by the Peavine anticlinorium (fig. 3A). 

The northwestern carbonate facies may be subdivided into three successive units. The lower unit 

is characterized by bedded chert and cherty carbonate. The middle and thickest unit is mainly noncherty limestone. The upper unit is cha.racterized by 

maroon, green, and gray mudstones and. shales. 

Boundaries between the three subdivisions are _gradational. 'The shale unit at the top of the Mississippian System grades upward into a sequence of sandstone, shale, and coal that has been assigned to the 

Pennsylvanian System. 

The southeastern clastic facies is mainly shale 

but also includes sandstone. The lower part of the 

southeastern clastic facies contains bedded chert 

similar to that in the bedded chert unit at the base 

of the northwestern carbonate facies. The clastic 

facies also contains interbeds of limestone similar 

to the limestone in the middle unit of the northwestern carbonate facies (fig. 4). The southeastern 

clastic facies of Mississippian. rocks is overlain by 

sandstone of the Pennsylvanian System. 

Lim.estone tongues within the southeastern clastic 

facies indicate a lateral transition characterized by 

intertonguing of the tw'O facies ; however, outcrop 

sections d.o not show the complete range of intermediate characteristics between the two facies .. 

Along the Peavine anticlinorium, in the probable 

area of facies transition, Mississippian rocks have 

been removed by erosion. Interpretation of structure of the anticlinorium (Butts, in Butts and 

Gildersleeve, 1948, geologic map) suggests only 

minor structural telescoping of the sedimentary 

facies. Some possible transitional aspects can be 

seen where the section is mostly limestone on Sand 

Mountain (Catoosa County) in the western northtrending branch of the Floyd synclinorium (fig. 

3A). To the south in the Floyd synclinorium, the 

Mississippian System i·s repres,ented by the clastic 

facies. Evidently the clastic facies grades northward 

to the carbonate facies along the western branch of 

the Floyd synclinorium, but details a.re obscure because of poor exposure. Ap·parently the facies 

boundary roughly parallels structural strike along 

the Peavine anticlinorium, but it trends somewhat 

more ea·sterly and extends into the Floyd synclinori urn on the north. 

Trends of major facies patterns are paralleled by 

major thickness trends in the Mississippian System 

(fig. 4). On the northwest, the carbonate facies 

ranges in thickness from approximately 360 to 460 

m. The system thickens to the southeast, and in the 

depression of the Floyd synclinorium the clastic 

facies is as much as 775 m thick. Because of poor 

exposure, thickness data for the clastic facies are 

sp·arse. Complex ·structure precludes a thickness 
H6 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

D 

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8 

0 

~ 

8~~~~~~--~~~~ 

L

OOMETERS 

00 

00 

0 KILOMmRS 

0 

LOCAL SECTIONS 

1 Composite Sections: HookerScratch Ankle HoDow 

2 Section: Trenton 

3 Section: Johnson Crook 

4 Section: Waterfail Branch 

5 Section: Nichols HoDow 

6 Core: U.S. Gypsum Co. 

7 Section: McLemore Cove 

8 Core: U.S. Gypsum Co. 

Section: Menlo 

9 Section: Sand Mountain 

10 WeD: Atlanta Gas Light Co. 

No. 1 Fitzpatrick 

11 Section: Littl_e Sand Mountain 

12 Cores: Georgia Power Co. 

(Rocky Mountain) 

13 Cores: Aorlda Rock Industries, 

Inc. 

14 WeD: Atlanta GaS Light Co. 

No.1 Camp 

-----

10 

EXPLANATION 

E!:J3 Limestone 

1- ,....j Shale-mudstone 

0 Sandstone 

E:±:J Chert nodules In 

limestone 

fi' : 1 ~~ Chert and limestone 

l- --..= l Argillaceous Umesto~e and calcareous shale 

LAVENDER 

--i-

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·~ 

20 KR.OMETERS 

9 ____. 

FIGURE 4.-Diagrammatic stratigraphic cross sections of Mississippian rocks in northwest Georgia. Top of each section is base of massive sandstone. Lithologic symbols on 

cross sections show the part of each local section that is 

included in available descriptive data. Letters A through 

F on cross sections show approximate stratigraphic positions of maps in figure 8. Data for local sections from 

Sullivan (1942) (section 3), Allen (1950) (section 9), 

Clement (1952) (section 3), Moore (1954) (section 2), 

Wheeler (1954) (sections 4, 5), Windham (1956) (section 

9) , Wilson ( 1965) (section 1) , McLemore ( 1971) (sections 1-5, 7-9, 11), Florida Rock Industries, Inc. (section 

13), Georgia Geological Survey (sections 10, 14), Georgia 

Power Co. (section 12), and U.S. Gypsum Co. (sections 

6, 8). 
GEORGIA H7 

measurement of Mississippian rocks on .the Ro·me 

fault block. 

EVOLUTION OF STRATIGRAPHIC NOMENCLATURE 

Pioneer stratigraphic work in Tennessee and 

Alabama led to the recognition of three major subdivisions of Carboniferous rocks (Safford, 1869; 

Smith, 1879). The Lo·wer Sub-Carboniferous or Siliceous group included the cherty beds that make up 

the lower part of the Mississippian in Georgia. The 

Upper Sub-Carboniferous or Mountain Limestone included the carbonate sequence of northwest Georgia. 

The Coal Measures apparently included the shale at 

the top of the Mississippian as well a~s the overlying sandstone-shale-coal sequence of the Pennsylvanian. 

The first identification o.f formation subdivisions 

in Georgia apparently is the work of Hayes (1891) 

Early Reports Hayes, 1891 Hayes, 1894 

NW SE NW 

Coal Measures 

(Millstone Grit) Coal Measures Lookout Sandstone 

Bangor Bangor Limestone Limestone, 

Upper Sub· .Oxmoor 

who extended the stratigraphic names Fort Payne 

Chert, Oxmoor Sandstone, and Bangor Limestone 

from Alabama. Hayes first used the name Floyd 

Shale for the lower part of the clastic sequence in 

Georgia (fig. 5). 

In quadrangle mapping at Ringgold and Rome, 

Hayes (1894; 1902) recognized the two geographically distinct s.equences of Mississippian rocks in 

Georgia. He used the name Bangor for all carbonate 

rocks above the Fort Payne Chert on the no·rthwest, 

and he used the names Floyd and Oxmoor for the 

shale and sandstone parts of the clastic sequence on 

the southeast (fig. 5). The name Bangor was also 

us·ed for a limestone unit above the Floyd and 

Oxmoor of the clastic sequence. Hayes (1894) specifically recognized that the clastic facies changes 

northwestward into the carbonate facies and that 

the Floyd on the southeast is the same age as the 

lower part of the Bangor on the northwest. 

Hayes, 1902 Geo~Wa State map; Georgia Div. 

Mines, ining, and Geology, 1939; Butts, Cressler, 1970 

SE NW in Butts and Gildersleeve, 1948 SE 

Pottsville Formation Sewanee 

Conglomerate 

Lookout Sandstone Gizzard Formation Gizzard 

Pennington Shale2 Formation 

Bangor Limestone Bangor Limestone Bangor 

Limestone 

Oxmoor Sandstone Hartselle Sandstone1 Hartse~~!~~stone Carboniferous 1 Banl)or Floyd Shale Cll 

or Bangor Limestone Golconda Limestone3 iii Limestone ~ 

Mountain Gasper Limestone3 (/) 

Limestone Floyd Shale Floyd Shale "'0 Floyd Shale* ~ Unnamed Ste. Genevieve Limestone3 u;: limestone 

St. Louis Limestone3 unit 

Tower Sub· Fort Payne Chert Fort Payne Chert 

Carboniferous or Fort Payne Chert1 Fort Payne Chert Fort Payne Chert Lavender Shale 

Siliceous Group Member* Lav:;ra~b:rhale 

Mclemore, 1971 Georgia State map; Georgia This Paper Rock Types 

NW SE NW Geological Survey, 1976 SE NW SE NW SE 

Sewanee Sandstone Sandstone 

Pennsylvanian 

Raccoon Mountain Formation Gizzard Formation Raccoon Mountain Formation Shale -sandstone 

Pennington Shale Pennington Shale Pennington Formation Shale 

Bangor ......,...,.... Bangor Limestone Bangor Limestone 0 

c:rn 

Ol Limestone Limestone =~ 

ls~~~~~~~e Harts~:~~~~stone I'I!Cil 

Hartselle Sandstone I[IC: Unnamed sandstone - - Sandstone cb2 Cll -rn Cll Limestone - Golconda Formation iii OlCI) iii - Shale 

Monteagle ~ mE ~ - Gasper Limestone ____ (/) c:::; (/) - -Sand~n! Limestone4 Floyd Shale "'0 0 "'0 

I Ste, Genev1eve Unnamed ~ ~ Unnamed > 0 Limestone limestone u;: limestone u;: Limestone 

Tuscumbia Limestone1 St. Louis Limestone member Tuscumbia Limestone member Cherty limestone 

Fort Payne Chert Fort Payne Chert Fort Payne Chert Chert Argillaceous limestoneLavender Shale Member Lavender Shale Member calcareous shale 

~~~en~:;,:f'J: f~g~i~7 1~ ~~org1a 2Name extended from Virginia 

3Name extended from MISSISSippi 

4Na~~e~xt~nd:J f~~~~s:n:ssee 

FIGURE 5.-Chart showing the evolution of stratigraphic subdivitsion and nomenclature of Mississippian rocks in northwest Georgia. 
H8 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

On the 1939 State geologic map of Georgia and 

in a subsequent report by Butts (in Butts and 

Gildersleeve, 1948, p. 3-79), s·everal formation 

names were extended into Georgia from the Mississippi Valley section (fig. 5). These subdivisions 

were based mainly on earlier work, in which Butts 

(1926) had extended the use of the Mississippi 

Valley units to Alabama. The same units were subsequently extended to Georgia from Alabama. 

Recognition of St. Loui,s, Ste. Genevieve, Gasper, 

and Golconda was based mainly upon the presence 

of certain distinctive faunal elements (Butts, in 

Butts and Gildersleeve, 1948, p. 45-48). Above the 

Golconda (of- Butts, 1926) in Alabama is an extensive sandstone unit, the Hartselle Sandstone. Originally the name Bangor_ Limestone had been· used in 

Alabama for the entire limestone sequence above 

the Fort Payne Chert (in that sense, Hayes, 1894, 

extended the use of Bangor into Georgia) , and 

Hartselle Sandstone had been recognized as a member of the Bangor (Thomas, 1972a, fig. 2). Later, 

Butts (1926) restricted the Bangor to limestone 

beds above the Hartselle Sandstone and raised 

Hartselle to formation rank. In the latter sense, 

Butts (in Butts and Gildersleeve, 1948, p. 48). 

extended .the use of Hartselle and Bangor into 

Georgia. 

The Hartselle Sandstone in Alabama is a distinctive sandstone unit locally as much as 50 m thick 

(Thomas, 1972a, pl. 10), and a sandstone and sandy 

limestone approximately 3 m thick marks the position of the Hartselle at the north end of Lookout 

Mountain in Chattanooga, Tenn. (Butts, in Butts 

and Gildersleeve, 1948, p. 48). However, the limestone sequence in Georgia ·contains no persistent 

sandstone unit at the stratigraphic position of· the 

Hartselle. Extension of the name Hartselle Sandstone from Alabama has led to a frustrating search 

for a rock unit to fit the stratigraphic name. 

Butts (in Butts and Gildersleeve, 1948, P'· 49) 

also extended the name Pennington from Alabama 

for the shale unit at the top of the Mississippian 

section (fig. 5). The name Pennington was defined 

in Virginia (Campbell, 1893, p·. 28) and had been 

extended to Alabama by Butts (1910). 

The clastic facies on the southeast in Georgia 

was assigned to the Floyd Shale· (Butts, in Butts 

and Gildersl,eeve, 1948, P'· 49-52). So defined, the 

Floyd included interbeds of limestone and ,sandstone, but stratigraphic names were not applied to 

any of these units (Butts in Butts. and Gildersleeve, 

1948, p. 50). Butts defined the Lavender Shale 

Member of the Fort Payne Chert as a dark-colored 

shale member (fig. 5). The Lavender Shale Member is restricted generally to the east of the area of 

the Fort Payne Chert. 

Preparation of county maps by Cressler (1970) 

led to further subdivision of the clastic facies (fig. 

5). A distinctive limestone tongue in the upper 

part of the clastic facies was identified as Bangor 

Limestone, following the usage of Hayes ( 1891). 

The clastic rocks below the Bangor and above the 

Fort Payne Chert were called Floyd Shale, and a 

sandstone unit near the top of the Floyd was designated the Hartselle Sandstone Member (Cressler, 

1970, p. 48). The Hartselle Sandstone Member as 

mapped by Cressler (1970) is. the same unit Hayes 

(1891; 1902) called Oxmoor Sandstone. Both names 

had been extended from Alabama, and the change 

introduced by Cressler reflected changes in ~subdivision and nomenclature of the Alaba.ma section. The 

Hartselle Sandstone in Alabama occupies a well-defined stratigraphic position, and Cressler's (1970) 

work extended the use· of the name into the clastic 

facies in Georgia. A limestone unit at the base of 

the Floyd Shale was mapped locally by Cressler 

(1970) as an unnamed limestone unit. 

In a dissertation, McLemore (1971) proposed revis'ions of some of the stratigraphic nomenclature 

to recognize lithologically distinct units (fig. 5). The 

name Tuscumbia was extended from Alabama for 

the lower cherty part of the carbonate facies above 

the Fort Payne Chert. Overlying the Tuscumbia is 

a noncherty limestone unit for which the name 

Monteagle Limestone was extended to Georgia from 

Tennessee. McLemore (1971) continued the use of 

the name Hartselle for a shaly and locally sandy unit 

that he identified within the carbonate facies between Monteagle and Bangor. Although the thickness of the complete Monteagle-Bangor interval is 

relatively constant, the stratigraphic position of the 

unit assigned to the Hartselle seems to vary abruptly from section to section resulting in ahrup·t reciprocal changes in thickness of beds assigned to 

Monteagle and to Bangor. It appears likely that the 

rocks designated as Hartselle are not a continuous 

clastic unit but rather are several local cla·stic 

lenses at different stratigraphic positions. McLemore 

(1971) also used the name Hartselle Sandstone for 

a sandstone unit within the clastic facies. 

Many of the formal stratigraphic names applied 

to Mississippian rocks in northwest Georgia have 

been extended from other areas, and subdivision of 

the Georgia succession has been designed to coliform to a scheme of subdivision defined elsewhere. 

Some units have been identified on the basis of rock 
GEORGIA H9 

characteristics, but many of the formation names 

that have been extended into Georgia were applied 

to subdivisions that were identified on the basis of 

their fossil content. Such units are biostratigraphic 

units in terms of modern concepts and are not neces·sarily distinct as rock-stratigraphic units. This review of the evolution of stratigraphic nomenclature 

in Georgia provides the background for recognition 

of units that are distinct on the basis of rock type, 

in keeping with a modern definition of rock-stratigraphic units (fig. 5). 

The rocks of the carbonate facies are divided 

herein into the Fort Payne Chert, Tuscumbia Limestone, Monteagle-Bangor Lim.estone-s undifferentiated, and Pennington Formation, in ascending 

order (fig. 5). The Fort Payne is characterized by 

bedded chert. The Tuscum.bia is cherty limestone. 

The Monteagle-Bangor sequence is characterized by 

bioclastic and oolitic limestones that contain very 

little chert. Maroon and green mudstone is characteris·tic of the Pennington, and the formation 

grades upward into a sequence of gray shale, sandstone, and coal. 

Because no persistent sandstone unit can be 

identified within the carbonate facies, the rockstratigraphic unit called Harts·elle cannot properly 

be identified in Georgia. The Hartselle Sandstone is 

a distinct rock-stratigraphic unit in Alabama, but 

isopach mapping shows that the Hartselle Sandstone pinches out eastward along an irregular northtrending line more than 65 km west of the GeorgiaAlabama State line (Thomas, 1972a, pl. 10). Because the Hartselle Sandstone of Alabama does not 

continue eastward into Georgia, and because the 

beds that have been assigned to the Hartselle in 

Georgia do not constitute a distinct rock-stratigraphic unit, it is inappropriate to continue the use 

of the name Hartselle in Georgia. Lack of a mappable stratigraphic unit precludes the need for a 

separate unit between Monteagle and Bangor. 

In northeastern Alabama the Monteagle and 

Bangor Limestones are differentiated because of 

the Hartselle Sandstone between them (Thomas, 

1972a, p. 22). East of the pinch-out of Hartselle 

Sandstone in Alabama, a contact between Bangor 

and Monteagle cannot be reliably traced, and the 

carbonate sequence can be identified best as Monteagle-Bangor undifferentiated (Thomas, 1972a, p. 

22). Us·e of Monteagle-Bangor undiffe·rentiated is a 

practical approach to the present problem of subdivision of the carbonate facies in northwest Georgia. 

On the 'southeast, the clastic facies.contains several 

stratigraphic units that have not been precisely defined. The lower part of the sequence has been called 

Floyd Shale, and the Floyd rests on either Fort 

Payne Chert or its facies equivalent, the Lavender 

Shale Member. The Lavender does not constitute a 

single distinctive member within the Fort Payne; 

rather it appears to be a laterally equivalent facies 

that intertongues with the entire Fort Payne Chert. 

In Floyd County, the Lavender or Fort Payne is 

overlain by a distinctive lim.estone unit that has 

been included within the Floyd Shale (Cressler, 

1970, p. 47). Presumably the limestone unit in the 

lower part of the clastic facies is a tongue of the 

lower part of the carbonate facies. However, because the limestone unit cannot be traced or precisely correlated to the carbonate sequence, it should 

be referred to as an unnam·ed limestone m.ember of 

the Floyd Shale or as a new formation, rather than 

as one of the named units of the carbonate sequence 

(fig. 5). 

Above the limestone unit the Floyd Shale is 

mainly shale and contains a few thin beds of sandstone and limestone. The shale sequence grades upward into a sandstone unit that has been called 

Hartselle. However,. the sandstone· is not physically 

continuous with the Hartselle Sandstone of Alabama but is separated from the Hartselle by a wide 

area in the carbonate facies of northwest Georgia 

and northeast Alabama. Therefore, the name Hartselle is inappropriate for the sandstone in the clastic 

facies in Georgia; however, no formal name is 

presently available (fig. 5). 

The sandstone unit is overlain by a tongue of the 

Bangor Limestone, and the Bangor is overlain by a 

shale unit in the stratigraphic position of the Pennington. Thus, the Pennington both on the northwest 

and southeast overlies Mississippian limestone and 

is overlain by sandstone and shale that are generally considered to be Pennsylvanian. 

LITHOSTRATIGRAPHY 

MAURY SHALE 

The Maury Shale is a thin, extensive, distinctive 

unit at the base of the Mississippian System in Alabama, Tennessee, and Georgia (Hass, 1956, p. 23; 

Conant and S~wanson, 1961, p. 66). The Maury consists of partly silty to sandy green and gray shale. 

The rocks are commonly glauconitic, and the formation characteristically contains phosphatic nodules 

(Wheeler, 1955; Conant and Swanson, 1961, p. 63). 

In Georgia, the formation is generally less than 2 

m thick. 
HlO THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

FORT PAYNE CHERT 

In weathered outcrops the Fort Payne Chert 

typically consists of light-colored chert in nodular 

beds less than one-fourth meter thick. The formation in northwest Georgia has a maximum thickness 

of more than 60 m (fig. 4). Much of the bedded chert 

evidently has been concentrated by the present 

weathering cycle from siliceous carbonate rocks. 

Cherty dolostone and cherty limestone (microfacies 

5, 6, and 8 of McLemore, 1971, p. 99; fig. 6) make 

up much of the formation. Parts of the formation 

include quartz geodes which contain relict anhydrite 

replaced by quartz and calcite (Chowns, 1972, p. 

90) . The weathered Fort Payne Chert commonly 

contains molds of echinoderm columnals· and other 

fossils. The Fort Payne Chert of northwest Georgia 

is part of a regionally extensive cherty facies that 

extends westward through the Fort Payne Chert of 

northern Alabama and Mississippi and is possibly 

continuous farther west with the upper part of the 

Arkansas Novaculite of the Ouachita Mountains in 

Arkansas (Thomas, 1972b, p. 96; 1977a, p. 16). In 

Georgia, the Fort Payne grades eastward into the 

Lavender Shale Member. 

MICROFACIES DESCRIPTION 

TUSCUMBIA LIM·ESTONE 

The Tuscumbia Limestone is· characterized by 

bioclastic limestone that contains relatively abundant nodules of chert. Chert appears to be scattered 

randomly through the formation, and no persistent 

marker beds have been defined. Beds of lime mudstone and finely crystalline dolostone are common ; 

dolomitic mudstones locally contain calcite pseudomorphs after gypsum (McLemore, 1971, p. 102). 

Argillaceous limestone and thin beds of calcareous 

shale are rare. The formation ranges from approximately 35 to 65 m. in thickness (fig. 4). 

The contacts of the Tuscumbia with the underlying Fort Payne Chert and the overlying Monteagle 

Limestone are gradational. The bedded chert of the 

F·ort Payne contrasts with the nodular chert o.f the 

Tuscumbia. The contact between the Tuscumbia and 

Monteagle is a regional upward change from cherty 

lim·estone to g·enerally noncherty oolitic limestone. 

The contact is arbitrarily placed above· the highest 

cherty lime mudstone and below the lowest thick 

oolitic limestone (McLemore, 1971, p. 102). However, the sequence above the arbitrary contact includes some thin cherty limestone, and thin beds of 

DEPOSITIONAL ENVIRONMENT 

1 Echinoderm grainstone and Shallow marine, outer platform of carbonate bank 

sparry echinoderm packstone High current energy 

2 Sparry bryozoan packstone and Protected shallow marine, inside bars (barrier rim) 

muddy bryozoan packstone Low current energy 

3 Oolitic grainstone and sparry Shallow marine, shoals or bars 

oolitic packstone High current energy 

4 Skeletal wackestone 

Shallow marine, protected lagoon 

Low current energy 

5 .Mudstone (lime mudstone) 

Shallow marine, lagoon between oolite shoals 

Low current energy 

6 Dolostone Shallow marine shelf, supratidal 

7 Muddy skeletal packstone 

Shallow marine, protected lagoon 

Low current energy 

a· Dolomitized limestone Partial dolomitization of shallow marine limestone 

FIGURE 6.-Chart showing microfacies of Mississippian carbonate rocks in George (modified from 

McLemore, 1971). 
GEORGIA H11 

oolitic limestone are present in the Tuscumbia. The 

contact as defined may not he practical for detailed 

mapping. 

MONTEAGLE-BANGOR LIMESTONES 

In the absence of a traceable contact between 

subdivisions, the upper part of the carbonate facies 

in Georgia is herein considered as MonteagleBangor Limestones undifferentiated. The MonteagleBangor sequence ranges fro·m 135 to 275 m in thickness (fig. 4) and is mainly oolitic and bioclastic 

lim.es.tone (microfacies 1, 2, and 3 of McLemore, 

1971; fig. 6). Thick beds of oolitic limestone are 

commonly crossbedded. The sequence includes beds 

of lime mudstone. Thin beds of dolostone and dolomitic limestone make up a small part of the unit, 

and dolostone locally contains scattered gypsum 

crystals.. Chert nodules in thin intervals· are scattered throughout the Monteagle-Bangor. Some 

cherty zones apparently extend laterally for short 

distances, but none are so extensive as to provide 

stratigraphic markers. 

The Monteagle-Bangor sequence includes a. few 

beds of argillaceous limestone and calcareous shale. 

The shaly ·intervals commonly are no more than 

10 m thick and include limestone interbeds. Shale 

interbeds appear to be randomly distributed 

throughout the sequence. Two shaly zones in the 

lower (Monteagle) part of the sequence apparently 

extend at least 25 ~ along the· Pigeon Mountain 

syncline. In northeastern Alabama, a shaly zone 

marks the middle Monteagle (Thomas, 1972a, p. 

21) , but that zone cannot be traced into Georgia. 

Locally, east of the pinch-out of the Hartselle Sandstone in Alabama, a thin shale marks the same stratigraphic horizon; but, the shale unit has limited extent (Thomas, 1972a, p. 42). Most of the shaly intervals ap·p·ear to have limited lateral extent in 

Georgia. Some shaly zones in the upper part of the 

succession locally contain thin beds of sandstone. 

The upper part of the limestone sequence gene·rally includes beds of gray calcareous shale and maroon 

and green mudstone, and the Monteagle-Bangor 

grades upward into the Pennington Formation. In 

southern Tennessee and northeastern Alabama, a 

distinctive dolostone unit marks the base of the 

Pennington (Ferguson and Stearns, 1967, p. 58; 

Thomas, 1972a, p. 84). Although the upper part of 

the Bangor in Georgia includes some dolostone 

beds, the marker unit has not been identified. 

PENNINGTON FORMATION AND RACCOON 

MOUNTAIN FORMATION ABOVE NORTHWESTERN 

CARBONATE FACIES 

Overlying the carbonate facies is a sequence of 

fine-grained clastic ·sediments approximately 65 to 

130 m thick (fig. 4) . The lower part of the sequence, 

the Pennington Formation, is characterized by 

maroon and green shale· and mudstone. Impressions 

of fenestrate bryozoans are abundant. The maroon 

and green mudstone grades up into dark-gray shale. 

The upper part of the sequence includes beds of 

siltstone and fine-grained sandstone, but locally the 

upper part contains maroon mudstone like that of 

the lower part. The upper, characteristically darkgray, sandstone-bearing part of the sequence evidently belongs to the Raccoon Mountain Formation 

as used in Tennessee (Culbertson, 1963, p. E56). 

The Pennington-Raccoon Mountain contact is 

within a gradational sequence that includes a variety 

of vertical arrangements of rock typ·es. The Tennessee Division of Geology defines the top of the Pennington as the top of the highest limestone or 

maroon and green mudstone (Milici, 1974, p. 118). 

The Raccoon Mountain Formation contains gray 

shale, sandstone, and coal. Sandstone units in the 

Raccoon Mountain appear to be laterally discontinuous. Siderite nodules are common in the shale 

units. On Sand Mountain (Dade County), the formation contains several coal beds. The overlying massive bluff-forming sandstone is formed by different 

stratigraphic units in different places (Wilson, 

1965, p. 28). 

LAVENDER SHALE MEMBER OF FORT PAYNE CHERT 

The Lavender Shale Member of the Fort Payne 

Chert consists of dark-gray calcareous shale and 

dark-gray argillaceous lime mudstone. The calcareous rocks weather to light-gray, greenish-gray, and 

yellowish-gray :shale and mudstone, and the type 

section of the member consists of weathered shale 

(Butts, in Butts and Gildersleeve, 1948, p. 44; 

Cressler, 1970, p. 45). Petrographic work shows 

that the typical rock of the Lavender, where unweathered, is as much as 75 percent. carbonate 

(Hurst, 1953, p. 218). 

The Lavender does not constitute a single unit 

within· the Fort Payne, and beds of Lavender rock 

types are distributed randomly within the Fort 

Payne Chert interval (Cressler, 1970, p .. 47). The 

Lavender includes discontinuous beds of chert. 

Thickness of the argillaceous rocks increases to·ward 

the east as the thickness of rocks typical of the Fort 

Payne Chert decreases. Beds of argillaceous rocks 
/ H12 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

are rare in the Fort Payne west of the Peavine anticlinorium, but farther east, the Lavender replaces 

most of the Fort Payne. The facies boundary between Lavender and Fort Payne apparently is a 

very irregular north-trending line through the Floyd 

synclinorium. On the Rome fault block in Polk 

County, thin intervals of Fort Payne Chert are 

found in scattered small thrust :slices, and the Fort 

Payne is replaced eastward across Polk County by 

the Lavender Shale Member (Cressler, 1970, p. 41). 

Near the depression of the Floyd synclinori urn, 

the Lavender Shale Member apparently is nearly 80 

m thick (fig.~). It is not clear whetJler the top of the 

Lavender is equivalent to the top of the Fort Payne 

or whether the Lavender also includes equivalents 

of some younger beds. 

UNNAMED LOWER LIMESTONE OF CLASTIC FACIES 

The lower part of the interval that commonly has 

been mapped as Floyd Shale is a limestone unit in 

the depression of the Floyd synclinori urn. The limestone may be more than 180 m thick (fig. 4). The 

lower limestone unit is characterized by bioclastic 

limestone, some of which contains coarse bioclasts. 

The unit also includes gray-black, very argillaceous 

lime mudstones that are. similar to the Lavender 

Shale Member. Some of the bioclastic limestone contains black nodular chert. The very argillaceous lime 

mudstone within the sequence of bioclastic limestones suggests intertonguing with the clastic facies. 

Farther south, on the Rome fault block in Polk 

County, the lower part of the Floyd is shale (slate), 

and evidently the limestone grades southward to 

shale. 

FLOYD SHALE 

The Floyd is characteristically dark-gray to black 

shale, part of which is calcareous and part of which 

is carbonaceous. The Floyd Shale above the unnamed lower limestone apparently is as much as 

290 m thick (fig. 4). Locally the shale contains 

siderite nodules, and at one locality in northwestern 

Polk .County :pyritk nodules in the shale contain 

fossils (Cressler, 1970, P'· 48). The Floyd includes 

thin ·beds of siltstone, sandstone, and limestone. 

Around Rocky Mountain, the unnamed lower limestone is overlain by calcareous· shale; but, around 

Little Sand Mountain north of Rocky Mountain, the 

unnamed lower limestone member of the Floyd is 

overlain by a sandstone unit approximately 11 m 

thick (fig. 4). The sandstone is characteristically 

fine grained but the lower part commonly is very 

fine grained and argillaceous. The lower part of the 

sandstone consists of thin ripple-laminated sandstones that have thin clay partings. Small unidentified plant fragments lie on bed surfaces. 

UNNAMED SANDSTONE AT TOP OF FLOYD SHALE 

Most of the Floyd Shale sequence contains. relatively little sandstone, but the shale· grades upward 

into a sandstone unit. The sandstone is fine to very 

fine grained and commonly is interlaminated with 

clay. The sandstone unit throughout most of its extent appears to be less than 20 m. thick (fig. 4) ; 

however, it is reported to be about 90 m thick on 

Judy Mountain west of Rome (Cressler, 1970, p. 

48). Because the outcrop on Judy Mountain is isolated by erosion from other exposures of the sandstone, correlation of the much thicker sandstone on 

Judy Mountain with the thinner sandstone elsewhere is uncertain. 

BANGOR LIMESTONE TONGUE OF SOUTHEASTERN 

CLASTIC FACIES 

The lim.estone interval within the southeastern 

clastic facies is as much as 200 m thick, but that 

interval includes beds of shale and sandstone (fig. 

4) . The Bangor tongue includes bioclastic limestone 

and argillaceous lime mudstone. Part of the bioclastic limestone contains nodules of dark-colored 

chert. The argillaceous lime mudstone weathers to 

massive clay that contains numerous impressions 

of fenestrat~e bryozoans. ·clastic beds within the Bangor tongue consist of dark-gray clay shale and finegrained sandstone, generally in thin wavy beds having partings of shale. The limestone interval and the 

sandstone-shale interbeds indicate repeated intertonguing of the clastic and carbonate facies. 

PENNINGTON FORMATION OF SOUTHEASTERN 

CLA,STIC F A!CIE.S 

Above the Bangor Limestone tongue is a darkcolored shale in the stratigraphic position of the 

Pennington Formation (fig. 4). The lower part of 

the Pennington includes thin beds of brownweathered claystone which contains molds of 

brachiopods; the claystone may be weathered from 

argillaceous limestone. The upper part of the Pennington includes thinly bedded sandstone and shale 

in which sandstone generally increases in abundance 

upward. Some sandstone beds have micaceous, carbonaceous laminae on top. Siderite nodules are common in parts of the .shale sequence. The Pennington 

Formation interval generally coarsens· upward and 

grades upward into a sandstone unit. Although correlation of the sandstone unit above the shale is un-
GEORGIA H13 

certa;in, it may be considered to mark the base of 

the Raccoon Mountain Formation. 

R~ACCOON MOUNTAIN FORMATION OF 

SOUTHEASTERN CLASTIC FACIE'S 

The sandstone at the base of the Raccoon Mountain Formation forms a prominent ledge on Rocky 

Mountain and Little Sand Mountain in Floyd and 

Chattooga Counties. The sandstone unit is locally 

more than 50 m thick (fig. 4) and consists of very 

fine to fine-grained slightly argillaceous sandstone. 

The beds are characteristically thin; some are ripple laminated. Carbonaceous, micaceous laminae 

mark the tops of sandstone beds, and clay partings 

are com.mon. Toward the top of the unit, the sandstone is more quartzose. Echinoderm columnals, 

bryozoan fragments, and possible brachiopod fragments are preserved in one sandstone bed. The sandstone is overlain by dark-colored shale, sim.ilar to 

the dark-colored shale below the sandstone unit. The 

upper shale interval is as much as 120 m thick (fig. 

4) and includes thin beds of sandstone and a few 

thin beds of limestone. Thin coaly beds are found 

in the lower part; siderite nodules are common in 

the upper part of the shale. The shale at the top of 

the Raccoon Mountain Formation is overlain by 

massive bluff-forming sandstone, part of which contains quartz pebbles. 

POSSIBLE FACIES TRANSITION 

The carbonate and clastic facies. in Georgia are 

distinct, but details of the facies transition are obscure. However, a section exposed around Sand 

Mountain in Catoosa County east of Ringgold shows 

features that suggest the nature of the facies transition. Because of complicated structure in the area, 

different authors have reported different thicknesses 

and stratigraphic sequences for Mississippian rocks 

(Allen, 1950; Windham, 1956; McLemore, 1971). 

The problem is mainly one of recognizing stratigraphic units, particularly the sandstone or sandstones. 

The section is mainly limestone, but the lower part 

is dominated by the Lavender Shale facies rather 

than the Fort Payne Chert (fig. 4). Above the Mississippian limestone sequence is a thin interval of 

maroon, green, and gray shale of the Pennington 

Formation. The Pennington is overlain by massive 

bluff-forming sandstone that contains quartz pebbles and that is considered to be Pennsylvanian. Between the La vender and Pennington, most outcrops 

are limestone. On Sand Mountain, a sandstone unit 

is exposed within the east-dipping limestone se- 1 

quence; and west of Sand Mountain on Cherokee 

Ridge, a sandstone is exposed within the east-dipping lim.estone sequence. On the assumption that 

the Hartselle Sandstone is the only sandstone within 

the limestone sequence in northwest Georgia, both 

the sandstone on Cherokee Ridge and the sandstone 

on Sand Mountain have been called Hartselle. That 

correlation requires that a thrust fault has duplicated the section between Sand Mountain and 

Cherokee Ridge and that the Mississippian section 

is 300 to 350 m thick (Windham, 1956; McLemore, 

1971, P·· 239). 

The sandstone on Cherokee Ridge is a distinctive 

light-gray fine-grained quartzose sandstone that is 

thick bedded to massive. Where exposed on Cherokee 

Ridge, this sandstone appears to be at least 15 m 

thick. The sandstone on Cherokee Ridge is associated with an interval of shale and sandstone which 

is more than 30 m thick (Allen, 1950, p. 150). In 

contrast, the sandstone on Sand Mountain is a 

brown slightly argillaceous fine-grained sandstone 

characterized by thin, irregular beds, some of which 

are ripple laminated. Clay partings are common. 

The contacts· betw·een the sandstone on Sand Mountain and the adjacent limestones are not exposed, 

but the interval that contains the ·sandstone apparently is not more than 12 'm thick. 

Both lithologic characteristics and thickness distinguish the sandstone on Sand Mountain from that 

on Cherokee Ridge. Evidently the two sandstones 

are not the· same but represent two different sandstone tongues within the carbonate facies. Following that interpretation, the amount of implied structural duplication is reduced. The thickness of Mississippian rocks may be nearly 500 m (fig. 4). 

Whereas a thickness of 300 to 350 m is anomalously 

thin for the Mississippian in Georgia, a thickness 

of 500 m is intermediate between that of the carbonate facies and the maximum for the clastic facies. 

The possible relationship of · the two clastic 

tongues in the limestone s·equence to the Floyd Shale 

farther south in the Floyd synclinori urn has not 

been established. The section on Sand Mountain 

east of Ringgold has some characteristics of the 

southeastern clastic facies but it is dominated 

(above the Lavender at least) by carbonate rocks 

similar to those of the northwestern carbonate 

facies. Regardless of interpretation of details, the 

section on Sand Mountain contains a large amount 

of carbonate rock and is more like the northwestern 

carbonate facies than the southeastern clastic 

facies. Facies strike, therefore, crosses structural 

strike along the western north-trending branch of 
H14 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

the Floyd synclinorium where the dastic sequence 

of the depression grades northward into the intermediate or carbonate sequence on Sand Mountain. 

PALEONTOLOGY 

BIOSTRATIGitAPHY 

The oldest formation in the Mississippian of 

northwest Georgia is the Maury Shale which overlies the Late Devonian Chattanooga Shale. Regional 

correlations b~sed on conodont studies :show that 

the Maury is of Kinderhook age and that the upper 

beds are probably Osage (Hass, 1956). 

The Fort Payne Chert contains a fauna of corals 

and brachiopods characteristic of the Keokuk and 

Burlington Formations of the standard Mississippian section of the Mississippi Valley (Butts, in 

Butts and Gildersleeve, 1948, p. 44). Among the 

typical fossils reported from the Fort Payne are 

"Hadrophyllum ovale, Zaphrentis cf. Z cliffordana, 

Z. compressa, large crinoid stems, one-half inch or 

more in diameter, Athyris lamellosa, Chonetes 

shumardanus, Linoproductus ovatus, Dictyoclostus 

(Productus) cf. D. crawfordsvillensis, D. cf. D. inflatus, D. cf. D. viminalis, Spirifer, · leidyi type, 

Spirifer rostellatus" (Butts, in Butts and Gildersleeve, 1948, p. 44). Cressler (1970, p. 42) collected 

Torynifer cf. T. pseudolineata, Leptogonia cf. L. 

analoga Brachythyris cf. B. suborbicularis, Spirifer 

sp., Cleiothyridina? s.p., echinoderms, and corals 

from the Fort Payne of Polk Gounty. 

The Lavender Shale Member of the Fort Payne 

Chert contains a bryozoan and brachiopod fauna 

which also demonstrates equivalence to the Burlington-Keokuk (Butts, in Butts and Gildersleeve, 

1948, p. 44). From the Lavender Shale Member, 

Butts (in Butts and Gildersleeve, 1948, p. 44) tentatively identified "Dictyonema sp., Cystodictya. 

linearis, H emitrypa near H. nodosa, Fenestrellina 

burlingtonensis, Fenestralina near funicula, F. multispinosa, F. regalis, F. near F. rudis, Brachythyris 

subcardiformis ?, Cleiothyridina glenparkensis, Dictyoclostus (Productus) burlingtonensis, Phaethonides spinosus." The Lavender Shale Member in 

Polk County has yielded Brachythyris sp., other 

brachiopods, Cypricardella or Cypricardinia sp., 

other pelecypods, Sinuitina? sp., other gastropods, 

and echinoderms (Cressler, 1970, p. 43). The trilobite, Australosutura georgiana, has been described 

from the Lavender Shale Mem·ber near Ringgold 

(Rich, 1966) and has been collected from the Fort 

Payne Chert in Alabama (McKinney, 1969) . 

The name Tuscumbia Limestone is now ap·plied 

to the cherty limestone beds which Butts (in Butts 

and Gildersleeve, 1948, p. 45) referred to the St. 

Louis Limestone. Like most o.f the other form·ation 

names that Butts extended from the Mississippi 

Valley section into Alabama and Georgia, the St. 

Louis was recognized mainly on the basis of its fossil fauna. Thus, the unit wa:s traced as a biostratigraphic zone rather than as a lithostratigraphic 

formation. The Tuscumbia (St. Louis) in Georgia 

is characterized by the presence of two species of 

corals, Lithostrotionella castelnaui and Lithostrotion proliferum (Butts, in Butts. and Gildersleeve, 

1948, p. 46). No fossils diagnostic of Warsaw and 

Salem have been reported from the section in 

Georgia, and Butts (in Butts and Gildersleeve, 1948, 

p. 42) concluded that a hiatus separates Fort Payne 

and St. Louis. However, the lower Tuscumbia in 

Alabama contains a Warsaw-Salem fauna (Drahovzal, 1967, p. 14). The lithologic succession in 

Georgia does not require an unconformity, and possibly the lack of Warsaw-Salem fossils is a result of 

factors other than a hiatus. 

The Monteagl,e-Bangor Limestones contain a characteristic Genevievian-Chesterian fauna. Butts (in 

Butts and Gildersleeve, 1948, p. 3-79) listed fossils 

representative of the Ste. Genevieve, Gasper, Golconda, and Glen Dean from the sequence now assigned to the Monteagle-Bangor. The units· Butts 

understood as formations are now defined as timestratigraphic units in Illinois (Swann, 1963). The 

succession is divided into Genevievian (Ste. Genevieve) , Gasperian (Gasper) , Hom:bergian ( Golconda-Glen Dean), and Elviran (post-Glen Dean) 

Stages (Swann, 1963, fig. 1). Because the definition 

of a formation used by Butts and others of his time 

was based on index fossils, the formations are directly comparable with time-stratigraphic subdivisions. Thus, Butts' work provides. a time-stratigraphic correlation with the Mississippi Valley 

section. 

The Monteagle contains the Ste. Genevieve guide 

fossil, Platycrinus penicillus (Butts, in Butts and 

Gildersleeve, 1948, p. 46; McLemore, 1971, p. 115). 

Gasper forms reported from Georgia include Talarocrinus, Campophyllum gasperense, Pentremites 

pyriformis, P. godoni, and Agassizocrinus ovalis 

(Butts, in Butts and Gildersleeve, 1948, p. 47). 

Lithostrotionoid corals, similar to the characteristic 

forms of the St. Louis, are found in association with 

Gasper faunas in the limestone sequence in northwest Georgia (Butts, in Butts and Gildersleeve, 

1948, p. 47) and in the Floyd Shale (Broadhead, 

1975, p. 33). The value of lithostrotionoids as guides 

to the M;eramec may be questioned in light of these 
GEORGIA H15 

associations. Beds equivalent to the Golconda are 

marked by Pterotocrinus capitalis (Butts, in Butts 

and Gildersleeve, 1948, p. 47). 

The Bangor contains a distinctive Glen Dean 

fauna including Pentremites cherokeeus, P. spicatus, Archimedes communis, A. meekanus, A. 

swallovanus, Fenestrellina cestriensis, F. serrulata, 

F. tenax, Prismopora serrulata, Septopora subquadrans, Polypora cestriensis, Composita subquadrata, and Spiriferina transversa (Butts, in 

Butts and Gildersleeve, 1948, p. 48). A collection 

from an outcrop of the Bangor Limestone and Pennington Formation northwest of Rising Fawn includes Pterotocrinus tridecibrachiatus, P. edestus, 

and Pentremites gutschicki; these forms indicate 

age equivalence of the upper Bangor to the Kinkaid 

Lim.estone of the Illinois basin (Waters and Chowns, 

1977). 

Fossils from the Floyd Shale include an age range 

of Meramec to Chester; index fossils are listed by 

Broadhead (1975, p. 30-31) as: 

Chester undifferentiated 

Cleiothyridina sublamellosa 

Reticulariina spinosa 

Spirifer leidyi 

Pentremites (godoni and pyriformis 

groups) 

Agassizocrinus 

Z eacrinites 

Middle Chester 

Cravenoceras 

Tylonautilus 

Lower Chester 

Talarocrinus 

Lyrogoniatites 

N eoglyphioceras 

Meramec 

Cystelasma 

Lithostrotionella 

Lithostrotion proliferum 

Perditocardinia dubia 

Forbesiocrinus 

Some assemblages from the Floyd contain forms 

characteristic of two successive stages; for example, 

one assemblage contains both the Lower Chesterian 

goniatite Lyrogoniatites and the Middle Chesterian 

goniatite C1·avenoceras (Broadhead, 1975, p. 32). 

Broadhead (p. 32) concludes that these. assemblages 

are from beds very near the stage boundary. The 

oldest fauna in the Floyd Shale includes both 

Cystelasma and Perditocardinia dubia which have 

been reported from the Salem Limestone (Broadhead, 1975, p. 34). The limestone unit within the 

lower Floyd contains Talarocrinus which is distinctive of the Gasper (Butts, in Butts and Gildersleeve, 

194·8, p. 51). Butts (in Butts and Gildersleeve, 1948, 

p. 51) reported fossils distinctive of St. Louis and 

Gasper from the Floyd east of Ringgold ; however, 

the section at that locality is mainly limestone like 

the Tuscumbia and Monteagle. Fossils collected 

from the Floyd Shale in western Polk County include Lyrogoniatites newsomi georgiensis, Goniatites cf. G. kentuckiensis, and N eoglyphioceras 

georgiensis which indicate an Early Chester age 

(Crawford, 1957, p. 46; Cressler, 1970, p·. 49). 

The youngest fossils from the Floyd are compatible with an age assignment that is equivalent 

to the Haney (upper Golconda) Limestone (Broadhead, 1975, p. 35). Within the clastic sequence, the 

sandstone at .the top of the Floyd Shale· has been 

assumed to be equivalent to the H·artselle Sandstone of Alabama, and the sandstone is overlain by 

a limestone that has been considered to be a tongue 

of the Bangor Lim·estone. The Bangor Limestone in 

the carbonate facies of northwest Georgia and Alabama contains a Glen Dean fauna; and, because of 

its position below the Bangor, the Hartselle Sandstone of Alabama has been assumed to be equivalent 

to the Hardinsburg Sandstone of the Mississippi 

Valley (Butts, 1926, p. 195). Limestone within the 

clastic sequence in northeastern Chattooga County 

has yielded specimens of Pentremites robustus 

which indicates age equivalence to Haney or Glen 

Dean (J. A. Waters, written com.mun., 1978). 

PALEOFJCOLOGY 

Fossil faunas indicate marine environments for 

Mississippian sediments in northwest Georgia. The 

carbonate facies o.f northwest Georgia is characterized by a brachiopod-bryozoan-echinoderm-coral 

fauna that indicates an open-marine-shelf environment. Echinoderm fragments are· associated with 

rock types that denote high current energy. (McLemore, 1971, p. 49). Rock types that suggest low 

current energy contain relatively large concentrations of bryozoans (McLemore, 1971, p. 104). Reeflike clusters of corals are less than 1 m in height 

and width (Owen, 1955). 

Broadhead (1975, 1976) has defined and characterized five communities of marine benthic organisms within the Floyd Shale (fig. 7). Definition 

of the communities has been based on the recogni-

.tion of a few groups of animals, and each of the 

communities may show much faunal diversity 

(Broadhead, 1975, p. 42; 1976, p. 268). Communi-
Hl6 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

COMMUNITY CHARACTERISTICS ROCK TYPES INTERPRETATION 

Low faunal diversity; Lingula; (1) Bioturbated sandy siltstone Prodelta or distal 

Lingula bryozoans, articulate brachiopods; and silty shale delta front fragments of terrestrial plants 

(2) High faunal diversity; lnflatia, 

Spirifer, Phestia, Aviculopecten; Silty shale to argillaceous Bivalvia-Spiriferida- Restricted bays 

Productidina bryozoans, echinoderms, gastropods; limestone 

fragments of terrestrial plants 

(3) Low faunal diversity; Fenestella, Bay, distal prodelta, 

Fe nest ell idae Archimedes; brachiopods Calcareous shale to siltstone mudbank 

High. faunal diversity; Pentremites, 

(4) Composita, Cleiothyridina, Spirifer, Calcareous shale to lime 

Pentremites-Spiriferida- Reticulariina, lnflatia, Michelinia; Open marine shelf 

Fenestellidae crinoids, gastropods, pelecypods, mudstone 

bryozoans 

(5) Low faunal diversity; Michelinia, Lime mudstone to bioclastic 

Michelinia-Rugosa Pentreinites; crinoids, brachiopods and oolitic limestone Carbonate bank 

FIGURE 7.-Chart showing marine benthic communities in the Floyd Shale (modified from Broadhead, 1975, 1976). 

ties 1, 2, and 3 reflect various components of a prograding delta., whereas communities 4 and 5 are 

associated with trans.gressive carbonate units that 

suggest delta destruction. Although understanding 

of the distribution of communities is complicawted 

by complex structure and some uncertainty in 

stratigraphic position, communities 1 and 2 are most 

common on the south and east, and community 5 is 

restricted to the north and west (Broadhead, 1976, 

p. 272). Com.munity 4 is widely distributed, but 

community 3 ·is relatively uncomm~on (Broadhead, 

1976, p. 272). The evident distribution pattern :suggests that a delta system prograded northward and 

(or) westward onto a marine shelf and that episodically delta lobes were abandoned and reworked. At 

a locality in Catoosa County, east of Ringgold, an 

oolitic and skeletal limestone containing community 

5 is overlain by about 1 m of silty limestone and 

siltstone that contains fragments of a terrestrial 

plant (Broadhead, 1975, p. 60; 1976, p. 271). The 

plant-bearing beds are overlain by calcareous shale 

and limestone containing community 4. This locality 

is in the probable area of facies transition and apparently is indicative of numerous, abruptly 

bounded tongues of the southeastern clastic facies 

within the carbonate facies. 

DEPOSITIONAL AND TECTONIC FRAMEWORK 

The major facies of Mississippian rocks. in northNest Georgia were deposited in two different depositional regimes. On the northwest is a carbonateshelf sequence and on the southeast is a fine-clastic 

sequence of prodelta and delta-front sediments. Intertonguing of the carbonate and clastic facies results from migration of the prograding delta front 

and epi:sodic transgression of the carbonate shelf 

facies over the deltaic sediments (fig. 4). The northwestern ·corner of Georgia remained in the carbonate-shelf regime throughout most of the MississiPpian. In latest Mississippian an extensive complex 

of clastic sediments prograded over the carbonate 

facies. 

The thinness and mineralogy of the Maury Shale 

suggest very slow accumulation of clastic sediments 

(McLemore, 1971, p. 99), and the Fort Payne Chert 

indicates the initial deposition of Mississippian carbonate sediments on the shallow-marine shelf. The 

as;sociation of dolostone and relict evaporites in the 

Fort Payne reflects a ;sabkha environment ( Chowns, 

1972, p. 90). On the east, the argillaceous limestone 

and calcareous shale of the Lavender Shale Member are evidently the most distal part of a sediment 

dispersal system and probably were deposited in 

deeper water off the shallow shelf (fig. 8A) . The -

broad area of mixing of carbonate and clastic sediments in the Lavender suggests that no abrupt 

shelf edge had formed. 

The Tuscumbia cherty limestones were deposited 

in an open-marine-shelf environment (fig. 8B). The 

Tuscumbia probably is correlative with at least the 

lower part of the lower limestone mem·ber of the 

Floyd Shale. If we assume that correlation, the Tuscumbia and related limestones extend farther ea:st 

than part of the Fort Payne Chert and represent a 
A 

I ----r--

~ ( 

.> 

) '.,._; 1\v 

n . ..___.J""¥,;;, 

E 

GEORGIA 

I ----r--

~ ( 

.> 

) '.,._; 

1\~ .n . ....__- _,_, ~ 

----r--

~ ( 

.> 

) '.,._; 

·v 

10 20 !KILOMETERS 

c 

F 

H17 

I ----r--

~ ( 

.> 

) '.,._; 1\v 

"'-""-- _ _,_,~ 

~----r--

~ ( 

.> 

) '.,._; 1\v 

n . ..,__ _ _,_,~ 

FIGURE B.-Generalized lithofacies and paleogeographic maps of Mississippian rocks in northwest Georgia. Approximate stratigraphic position of each map is shown by letter on cross sections in figure 4. Line pattern indicates approximate area of facies 

transition. A. Fort Payne Chert/Lavender Shale Member. B. Tuscumbia Limestone/unnamed lower limestone/Floyd Shale. C. 

Lower part of Monteagle-Bangor Limestones/Floyd Shale. D. Middle part of Monteagle-Bangor Limestones/unnamed sandstone/ 

Floyd Shale. E. Upper part of Monteagle-Bangor Limestones/Bangor Limestone tongue in clastic facies/Floyd Shale. F. Pennington Formation/Raccoon Mountain Formation/top of Bangor Limestone. 

transgression of the shallow-marine shelf over the 

muddy sediments of the Lavender. 

The Monteagle-Bangor sequence demonstrates 

persistence of the carbonate shelf (fig. SC, SD, and 

BE). The sequence is mainly composed of oolitic and 

bioclastic limestones that indicate high-current 

energy on shoals and bars of a carbonate bank ( McLemore, 1971; fig. 6). Lime mudstones and muddy 

bioclastic limestones indicate deposition on the shelf 

in protected lagoons between oolite shoals. Rare 

dolostones suggest local supratidal areas on the 

shelf. Rare beds of shale represent the most distal 

outwash from laterally equivalent clastic facies. 

On the southeast, the fine clastic sequence of the 

Floyd Shale consists mainly of prodelta muds (fig. 

SC). Benthic faunal communities in the Floyd sug-
H18 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

gest distal prodelta, delta front, and marine-bay 

environments (Broadhead, 1975; 1976; fig. 7). On 

the Rome fault block, prodelta shales rest directly 

on Fort Payne Chert (compare fig. SA with fig. 8B). 

Farther northwest, the prodelta shales overlie the 

lower limestone member of the Floyd ( com.pare fig. 

BB with fig. 8C). The lower limestone is evidently 

equivalent to the lower part of the carbonate facies, 

presumably Tuscumbia and part or all of Monteagle. 

These relations indicate northwestward progradation of the prodelta sediments onto the carbonate 

shelf. Argillaceous zones within the lower limestone 

indicate pulses in the general progradation. 

Sandstone units in the Floyd Shale are delta-front 

sands (fig. 8C and 8D). The sequence locally 

coarsens upward from shale into sand through a 

fine-grained ripple-laminated sand. The upper part 

of each sand unit is generally more thick bedded 

and quartzose. At least two different sandstone units 

are present: one just above the lower limestone unit, 

the other at the top of the Floyd (fig. 4). 

Because of the small outcrop area and poor exposures, insufficient data are available to define the 

extent of the sandstone units, and details of geometry of the delta-front facies are unknown. The 

deltaic sediments locally prograded northwestward, 

and distribution of facies demonstrates that clastic 

sediment was transported into the area south and 

east of the carbonate facies. Presumably the preserved delta-front S·ediments were supplied through 

a fluvial system, but the orientation of the fluvial 

system and the location of the source of the sediment presently cannot he defined. 

Other Mississippian clastic facies in the region 

indicate similar deltaic deposition, and for some of 

these the directions of progradation are better defined. On the west in Alabama, a deltaic sandstoneshale sequence in the Parkwood Formation progrades northeastward onto the western part of the 

Bangor Limestone (Thomas, 1972a, p. 81; 1974, p. 

196). Along Appalachian synclines in Alabama the 

Parkwood deltaic sandstones reach their maximum 

eastward extent but apparently are limited to the 

west of the Georgia-Alabama State line. Thus, the 

sandstone units in the Floyd Shale of Georgia evidently are not continuous with the Parkwood sandstones presently exposed in Alabama. Furthermore, 

the most extensive Parkwood sandstones are in the 

upper part of the Mississippian section in Alabama, 

and the most extensive sandstones· in the section in 

Georgia appear to be older. 

To the north in Tennessee, a clastic sequence of 

Pennington, Raccoon Mountain, and younger units 

progrades southwestward over the Mississippian 

carbonate facies (Ferm and others, 1972, fig. 3). 

However, that clastic wedge progrades over the 

Bangor Limestone in Georgia and is younger than 

the deltaic sandstones of the Floyd (fig. 4). Older 

Mississippian ciastic rocks are p·reserved locally in 

the Greasy Cove Formation in eastern Tennessee 

(Neuman and Wilson, 1960); but, because of limited 

exposure, the original extent of that unit is 

unknown. 

Possibly the fluvial system that fed the deltaic 

facies in Georgia originated in the same provenance 

as did the Parkwood system of Alabama or in the 

same provenance as did the Greasy Cove clastic 

rocks on the north in Tennes,see. Either source 

requires a long fluvial system outs.ide (on the south 

or east) the lim,its of presently preserved Mississippian strata in Georgia. Alternatively, the sandstones 

in Georgia may have had local sources to the south 

or east. Regardless o.f the location of the sediment 

source, preserved rocks in Georgia are in the prod~lta and delta-front facies (fig. 8C and 8D). No 

se:~iments of the delta plain have been recognized. 

A.n extensive tongue of Bangor Limestone indicates marine transgression over the deltaic sandstone facies (fig. 8E). The contact between the 

sandstone and overlying transgressive limestone is 

not ~~pos.ed, and details of destructional reworking 

of the abandoned delta lobe cannot be defined on the 

basis of available data. Within the limestone tongue 

another shale-sandstone unit indicates another pulse 

of delta progradation that was followed by delta 

destruction and deposition of the upper part of the 

Iim.estone. 

The Bangor grades upward into marine shale of 

the Pennington, and the Pennington grades upward 

from maroon and green mudstone to gray shale. 

The upper part of the shale srequence contains 

siderite nodules and carbonaceous beds as well 

as sandstone .interbeds. The Pennington-Raccoon 

Mountain sequence represents the transition ftom 

marginal marine to bay and lagoonal sediments (fig. 

SF). A few local bar sands are included. The finegrained clastic sequence is· overlain by massive ,sandstone of a barrier complex ( Ferm and others, 1972) . 

The clastic sediments in the upper part of the Mississippian in Georgia are part of a large-scale clastic 

wedge that prograded southwestward over the Mississippian carbonate facies (Thomas, 1974, p. 205; 

1977b, p. 1258). 
GEORGIA H19 

PENNSYLVANIAN STRATIGRAPHY OF 

NORTHWEST GEORGIA 

BY HOWARD R. CRAMER 

LITHOFACIES 

Pennsylvanian sedimentary rocks are confined to 

Chattooga, Dade, Walker, Catoosa, and Floyd 

Counties (figs. 3 and 9), and have been summarized 

in three major regional studies (Wanless, 1946; 

Stearns and Mitchum, 1962; McKee and others, 

1975). The rocks are almost entirely clastic and are~ 

in approximate order of abundance: sandstone, siltstone, shale, coal, clay (as underclay) , and siderite 

(also called ironstone) . Some of the clastic rocks are 

cemented by carbonate. Very little limestone is 

known. 

'Coal is the major economic resource of the Pennsylvanian rocks, and has been the subject of many 

reports. The works of McCallie (1904) and Johnson 

t 

100 METERS 

50 

0 

EXPLANATION 

[J Pennsylvania outcrop 

--- Possible fault 

10 20 30 KILOMETERS 

A 8 c 

B 

(1946) remain the most comprehensive studies of 

the coal and enclosing rocks to date, although much 

detail can be gleaned from the publications of the 

U.S. Geological Survey and the U.S. Bureau of 

Mines. 

EVOLUTION OF STRATIGRAPHIC NOMENCLATURE 

Coal-bearing rocks have long been known from 

Georgia. Maclure's map (1809) showed the rocks to 

be Secondary in age (following the W ernerian 

s·cheme), and his text alluded to ·coal. Williams' map 

(in White, 1849) showed the rocks to be Transition 

in age (still following the Wernerian scheme) and 

outlined two distinct coal terranes, one in Dade 

County and the other in Walker County. Hayes 

(1892) was the first to subdivide the Pennsylvanian 

rocks of Georgia. He recognized two distinct units, 

the Lookout Sandstone below and the Walden Sandstone above. 

D EFGH JK 

EXPLANATION 

Bluff- forming sandstone 

Other sandstone and siltstone 

Shale and clay 

8 Bangor Limestone 

Other limestone 

• Coal 

o Marine fossils 

FIGURE 9.-Generalized columnar sections showing Pennsylvanian and Mississippian rocks above the Bangor Limestone. 
H20 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Other studies of Pennsylvanian rocks in nearby 

States, notably Alabama and Tennessee, have resulted in nomenclature which has been later introduced for the rocks of Georgia. Culbertson (1963) 

summarized the history of Pennsylvanian nomenclature in Georgia. 

More recently, the U.S. Geological Survey Pennsylvanian paleotectonic study (McKee and others, 

1975) included much data about the Pennsylvanian 

of Georgia; the rocks are included in the stratigraphic category of Interval A. The stratigraphic 

nomenclature has been deliberately simplified for 

regional comprehension. 

Most recently, the geologic map o.f Georgia 

(Georgia Geological Survey, 1976) has been revised, 

and the twofold subdivision of the rocks proposed 

by Hayes (1892) has· been retained. Figure 10 

shows the nomenclature that has been used for the 

Pennsylvanian rocks of Georgia. Because the rock 

succession consists of alternating units of sandstones and gray shales and siltstones, the identification and tracing of a common reference unit is difficult, causing much confusion in the nomenclature .. 

The figure shows: (a) That there have been numerous interpretations for the same rocks, (b) that uncertainties exist even in the most recent interpretations, and (c) why the nomenclature used in this 

report has been simplified. 

In order to avoid introducing any new nam·es into 

what is intended to be a summary, no form.al stratigraphic nomenclature is used in this report; all of 

the rocks are Early Pennsylvanian, or Pottsvillian 

in age. 

Generally, the Pennsylvanian of Georgia is exposed in sandstone-capped plateaus and mountain 

tops, and these topographic features can be used 

for reference. Three categories of Pennsylvanian 

rocks· can be recognized: (a) Massive bluff-forming 

sandstone on the brow of the plateaus at the top of 

steep slopes. Massive sandstone may be found in the 

rocks below the bluff-forming sandstone, giving the 

impression of two sandstone bluffs. In these places, 

notably near Cloudland, the upper one is ·considered 

the bluff-forming sandstone. (b) Rocks stratigraphically, and general topographically, above the bluffforming sandstone. (c) Rocks below the bluff-forming sandstone exposed in the steep slopes of the 

plateaus and above the Mississippian MonteagleBangor Limestones. 

This threefold subdivision is used entirely for 

reference, and no stratigraphic correlation is intended. For instance, the bluff-forming sandstone is 

probably not everywhere the same continuous stratigraphic unit. It has been called by different researchers in different places, the Flat Rock Sandstone, the Warren Point Sandstone, the Sewanee 

Conglom:erate, the Lookout Sandstone, or the Bon 

Air Sandstone. 

LITHOSTRATIGRAPHY 

Correlation problems result from. many factors, 

economic, topographic, and stratigraphic. 

During the years when the stratigraphy of the 

area was being defined, coal mining was not extensive, and was entirely underground, providing few 

or no map's of value to the modern stratigr.apher. 

Now strip mining is taking plaee, although only in 

very limited areas. 

Topographically, problems result from the generally p-oor exposures on the talus-covered steep 

slopes of the plateaus and on the flat terrane of the 

plateau surfaces. Sandstone or conglomerate forms 

the brow of the plateaus, and as many similar-appearing sandstones and conglomerates are in the 

section, visual tracing is the only way to correlate 

one rock unit with another. 

Stratigraphically, correlation is difficult because: 

(a) Measured sections taken from the literature are 

often incomplete because of the topographic difficulties cited, or are very old and not sufficiently detailed for modern stratigraphic interpretation. (b) 

Sections often encompass several miles of horizontal 

traverse to include but a few hundred feet of vertical section. In view of the rapid horizontal facies 

changes known, such sections, if presented vertically, would be misleading. (c) Almost all of the previous correlations have been based upon the assumption that the rocks are in continuous blankets, 

especially the coal seams. The rocks are now suspected to be of deltaic or littoral origin, and as such 

would have very limited horizontal continuation. 

(d) The common oecurrence of sedimentation features such as pebble beds and zones, crossbedding, 

flaser bedding, and so on, both in horizontal and 

vertical context, make the use of these features extremely sensitive for correlation over any but immediate outcrop distances. (e) Almost no paleontol- ~ 

ogical data are available except for a few floral lists 

from uncertain stratigraphic and geographic localities (just enough to show the rock to be Early 

Pennsylvanian). (f) Uncertain, but probable, structural complexities in the region may have juxtaposed distinctly different stratigraphic or sedimentologic units. 

Another correlation problem relates to the base 

of the Pennsylvanian System, at its contact with the 
UNDERLYING 

ROCKS 

Upper SubCarboniferous 

Bangor 

Limestone 

Pennington 

Formation 

Pennington 

Formation 

Pennington 

Formation 

Pennington 

Formation 

Pennington 

Formation 

Pennington 

Formation 

Pennington 

Formation 

Pennington 

Formation 

Pennington 

Formation 

Pennington 

Formation 

GEORGIA 

PENNSYLVANIAN ROCKS 

Coal Measures 

Lookout Sandstone Walden Sandstone 

Pottsville Formation 

Lookout Formation 

Lower Upper Walden Formation 

Unnamed Conglom Unnamed Conglomerate erate 

lookout Formation 

Whitwell Shale Bonair Vandever 

Gizzard Sewanee Rockcastle Sandstone Sandstone Shale 

Member Member 

Lee Group 

Warren Sewanee WhitWell Newton Unnamed Point Gizzard Formation Conglom- Shale Eastland Sandstone Sandstone Sandstone erate 

Carboniferous (on map) 

Pennsylvanian (in legend) 

Pottsville Formation (in text) 

Pottsville Series 

New River Group 

Gizzard Formation Crab Orchard Mountains Group 

Raccoon Warren Sewanee Whitwell Newton RockMountain Point Signai.Point Conglom- Vandever castle 

Formation Sandstone Shale erate Shale Sandstone Shale Sandstone 

Gizzard Group Crab Orchard Mountains Group Q) 

> oc: .:00: uo t..) Warren Sewanee -g·~ 0 Signal Point cc Point Con glom- oE 

~a - Shale ou. ~ Sandstone erate 

z 

Interval A2 

Lookout Sandstone 

Sewanee Pennsylvanian 

Gizzard Formation Conglom- undifferentiated 

erate 

Bluff-forming sandstone 

Rocks below bluff-formina sandstone Rocks above bluff-forming sandstone 

AUTHOR AND 

DATE 

Little 1876 

Hayes 1892 

H21 

Georgia Div. of Mines, 

Mining and Geology 

1939 

Moore and 

others 1944 

Johnson 1946 

Wanless 1946 

Butts and 

Gildersleeve 

1948 

Stearns and 

Mitchum 1962 

Culbertson 1963 

Wilson 1965 

McKee and 

others 1975 

Georgia Geological 

Survey 1976 

This paper 

FIGURE 10.-Correlation chart showing the evolution of Pennsylvanian nomenclaturn in Georgia. 
H22 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

underlying Mississippian System. The actual level 

of the contact in the succession of rocks below the 

bluff-forming sandstone is unclear, and has been 

much discussed in the literature; in som.e places the 

bluff-forming sandstone may he Mississippian. 

The rocks below the bluff-forming sandstone are 

predominantly shale containing bedded sandstone 

and coal (fig. 9). The sandstones may be well developed and several meters thick. A small amount 

of nodular and laminar siderite is found in some 

localities. The paleobotanical data are· sparse; only 

a few plants and no palynomorphs have been described. Only recently have marine invertebrates 

been discovered in these rocks immediately below 

the bluff-forming sandstone, and these have not yet 

been evaluated. These rocks have been called the 

Raccoon Mountain Formation, the Gizzard Formation, and the lower part of the Lookout Sandstone. 

Underlying this sandstone and shale sequence is 

another sequence of clastic rocks, mainly shale, but 

including limestone, a little sandstone, and a small 

amount of coal and siderite. These clastic beds contain, in some localities, unquestioned Mississippian 

marine fossils, and are generally included in the 

Pennington Formation. These rest upon unquestioned marine limestones of the Monteagle-Bangor 

sequence. 

The contact between the clastic Pennington rocks 

and the clastic rocks overlying them is not obvious 

in the field. Some geologists separate the two sequences on the basis of unconformity, but because 

of the nature of the sedimentation, there are several unconformities within them. Other geologists 

separate the two sequences on the basis of lithology, 

but it can be shown that the lithology of each formation is not unique, and the exposures. are generally poor. Still other geologists would separate the 

two sequences on the basis of fossils, but fossils are 

sparse. 

Accordingly, in the following discussion, and on 

figure 9, thes.e rocks are not separated, but are included together in the clastic sequence known as the 

"rocks below the bluff-forming sandstone" and 

above the Monteagle-Bangor Limestones. 

For the above reasons, it seems prudent to describe the Pennsylvanian rocks of Georgia purely 

as vertical lithologic successions and to avoid any 

horizontal correlation. Cores are important because 

they show the true vertical sequence and lithology 

of the sediments. Unfortunately, some of the more 

important ·sedimentary characteristics needed for 

correlation are not recovered from cores, particularly sedimentary structures and their orientation. Core 

data are used wherever pos.sible in the following discussions, and are supplemented by data from nearby 

outcrops where possible. 

The following discussions of Pennsylvanian rocks 

are taken from the most recently-published geologic 

map of Georgia (Georgia Geological Survey, 1976), 

from the published accounts from which the map 

was prepared, and from fieldwork by the authors. 

PENNSYLVANIAN ROCKS ON SAND MOUNTAIN, 

GATOOSA COUNTY 

Sand Mountain in Catoosa County (fig. 9, locality 

A) contains a small outlier o.f Pennsylvanian rocks 

preserved in a syncline at the northern part of the 

Floyd synclinorium. Pennsylvanian rocks underlie 

only a few hundred square meters at the crest o.f 

the mountain. 

No cores are known. The section illustrated in 

figure 9 is taken from two sources. The upper part, 

the bluff-forming sandstone, is taken from Allen 

(1950, p. 158), and the lower part, rocks below the 

bluff-forming sandstone, are from McLemore ( 1971, 

p. 239). The section is at the crest o.f the mountain. 

The bluff-forming sandstone ·consists entirely of 

massively bedded, cross·bedded, conglomeratic quartz 

sandstone, 46 m thick. It has been called the Pottsville by Allen (1950), the Lookout Sandstone by 

Hayes (1894) and Cressler (1963), and on the 

present geologic map of the State (Georgia Geological Survey, 1976). McLemore (1971) called these 

rocks the Raccoon Mountain Formation. 

The rocks below the bluff-forming s·andstone are 

poorly exposed, but are entirely shale, 29 m thick. 

In this area, the rocks were called the Pennington 

Formation by Allen (1950) and Me Lemore (1971) 

and were considered Mississippian in age. 

No coals are known, and the basis for considering 

the bluff-forming sandstone Pennsylvanian is entirely its stratigraphic position. No fossils are reported 

from the Pennington Formation ·at this locality, and 

its age is considered Mississippian on the basis of 

its regional distribution and stratigraphic position. 

PENNSYL V ANlAN ROCKS ON LITTLE SAND 

MOUNTAIN, CHATTOOGA COUNTY 

Pennsylvanian rocks are mapped as constituting 

the entire mountain, and are preserved in the Floyd 

synclinorium (fig. 9, locality B). These are among 

the least known Pennsylvanian rocks in Georgia, 

and to this date, no measured section has been pubHshed. A brief description by Spencer ( 1893, p. 

127) is the only published account: 

a remnant of the Coal Measures occurs on Little Sand 

Mountain, which rises from 300 to 500 feet above the valley. 
GEORGIA H23 

The lower part of the mountain consists of shale succeeded 

by sandstone, which are massive, but in layers of mode-rate 

thickness. The surface of the southern end of the mountain 

forms a basin, drained by Mill Creek, which cascades over 

a ledge of sandstone 15 or 20 feet thick. Descending the 

little chasm of the horse-shoe falls, there is a layer of rock, 

more or less shaly, having a thickness of 15 inches, through 

which a dozen seams of coal are scattered, each with a 

thickness of a quarter or half an inch. From this plateau a 

ridge extends some miles northward, composed of the same 

rock. No other coal is known upon it other than that just 

described. 

The section illustrated in figure 9 has been compiled from field reconnaissance, topographic maps 

and aerial photographs, and from a generalized description of par:t of it given by Me Lemore (1971, 

p. 246). All the rocks described are from the southern part of the mountain. 

The beds overlying the Monteagle-Bangor Limestones and below the bluff-forming :sandstone consist o.f about 121 m of ·clastic rocks, the lower 56 

m of which are mainly gray and green shale containing siderite nodules and fenestrate bryozoans. 

Overlying this shale sequence is about 30 m of thinbedded, fl·aggy, fine-grained sandstone which contains a marine fauna of fenestrate bryozoans, 

echinoderm columnals, and possibly brachiopods; 

this fauna has not yet been evaluated. 

Overlying this sandstone is a poorly exposed section of about 35 m of gray ·shale. 

The ·bluff-forming sandstone apparently rests 

unconformably upon the gray shale, is about 15 m 

thick, is massively bedded at the base, and more 

thinly bedded toward the top. The· quartz sandstone 

contains discrete beds of ·conglomerate containing 

quartz pebbles as much as 1 em in diameter. 

The bluff-forming sandstone is overlain by an unknown thickness of gray shale that fills the bowl 

o.f the basin at the southern end of the mountain; 

the sandstone forms the rim. The shale is at least 10 

m thick. 

Me Lemore (1971, p. 246) considered the clastic 

rocks a:bove the Bangor Limestone and below the 

thin-bedded, fine-grained sandstone to be the Mississippian Pennington Formation, and the thin-bedded, 

fine-grained sandstone to be the basal sandstone 

in the Raccoon Mountain Formation. The 1939 geologic map o.f the State (Georgia Div. Mines, Mining, 

and Geology, 1939) showed all the rocks above the 

shale to be Pottsville as did Cressler ( 1970). The 

most recent geologic map of the State (Georgia Geological Survey, 1976) has the rocks mapped as 

Pennsylvanian undifferentiated. 

For this report, the ~lowermost clastic rocks are 

considered Mis.sis·sippian on the basis of regional 

facies considerations and paleontology. The bluffforming sandstone is considered Pennsylvanian only 

on the basis of its stratigraphic position. 

PENNSYLVANIAN ROCKS ON ROCKY [ROCK] 

MOUNTAIN, FLOYD COUNTY 

Rocky Mountain, called Rock Mountain on the 

71/2""minute quadrangle, contains an outlier of Pennsylvanian rocks preserved in a syncline within the 

Floyd synclinorium (fi·g. 9, locality C). 

Natural exposures on the rugged slopes are extremely 'poor, resulting :in very limited and incomplete knowledge of the section from surface exposures. Recently, however, the Georgia Power Co. 

has investigated the mountain in regard to construction of a pump-storage facility, and has taken 

numerous cores. The section illustrated in figure 9 

is prepared from several of these co·res which overlap to form a co.mplete section. The top of the section is within a few feet of the top ·of the mountain, both topographically ·and stratigraphically. 

The lowermost 75 m of rocks, those above the 

Bangor Limestone, are mainly shale containing beds 

of limestone and carbonatic .sandstone, with a few 

thin seams of coal near the top. Above these beds 

are about 55 m of thin-bedded, fine-grained sandstone which form's ledges or steps on the slope of the 

mountain, and which contains marine fossils. 

This ledge-forming, thin-bedded, fine-grained 

sandstone is overlain by 120 m of gray shale containing ·a few beds of sandstone, ·some of which are 

fossiliferous. 

Ahove this shaly sequence is about 40 m of bluffforming sandstone which is massively bedded, crossbedded, channeled, and medium to coarse grained; 

it is somewhat thinner bedded toward the top, and 

conglomeratic throughout. This unit forms the 

prominent sca:r.p around the top ·of the mountain. 

Over the bluff-forming sandstone is a gray shale 

sequence, 63 m thick, which contains a few beds of 

carbonatic, medium-grained, arkosic sandstone, and 

a marine fauna of· gastropods, pelecypods, orthoconic nautiloids, fenestrate bryozoans and brachiopods. 

Published accounts of the rocks on Rocky Mountain are unclear about the nomenclature used· for 

the rocks below the bluff-forming sandstone. The 

lower, sha1y part regionally resembles the Pennington Formation of Missis,sippian age, but no basis 

exists for an age assignment for the fine-grained 

sandstone nor for the bluff-forming sandstone and 

the rocks above it except for the marine fossils 

which have not yet been evaluated. No coal,s other 
H24 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

than the thin seams mentioned are known. The bluffforming sandstone is generally considered to be 

Pottsville on the basis of its lithology and stratigraphic position. 

PENNSYLVANIAN ROCKS ON PIGEON MOUNTAIN 

AND ON THE SOUTHERN PART OF LOOKOUT 

MOUNTAIN, CHA TTOOGA, DADE, AND WALKER 

CO UNTIE'S 

Lookout Mountain and Pigeon Mountain together 

form a sigmoidal-shaped, flat-topped plateau west 

of the Peavine anticlinorium. Because the section on 

the southern part o.f Lookout Mountain is different 

from the· sectiqn on the northern part, and because 

a structural discontinuity may be between them, it 

seems practical to discuss the two parts of the mountain separately ; the rocks on Pigeon Mountain are 

continuous with the rocks on the southern part of 

Lookout Mountain. The line of distinction between 

the northern and southern parts of Lookout Mountain appears to trend northeastward (figs. 3 and 9) 

from the narrow constrictivn between the two to 

the place where the fauJt intersects the eastern 

brow of the mountain. 

The well-known coal deposits on Lookout Mountain have been much studied in the past, and 

numerous sections have been measured, hut none 

is complete because of the poor exposures ·everywhere except on the brow of the :plateau. Fortunately the U.S. Gypsum Co. has drilled some cores 

on the mountain for the purpose of finding evaporites in the underlying Mississippian limestone, and 

the,se holes pass through the entire Pennsylvanian 

section in that locality. 

The most com.plete of these cores, and the one used 

for figure 9, locality D, is near the community of 

Cloudland, at an altitude of 443 m. 

The beds between the Monteagle-Bangor Limestones and the bluff-forming sandstone are 150 m 

thick The lower 110 m are mainly shale containing 

some .fossiliferous limestone beds near the base. The 

upper 40 m are mainly quartz sandstones with interbedded shale; the sandstones form ledges, so·me 

very pronounced on the steep slopes, so that two 

bluffs are present. Goal is associated with the uppermost sandstone and shale. 

Hobday (1974," p. 217-218) provided a measured 

section of some of these strata from the brow of the 

plateau nearby. He described the bluff-forming 

sandstone and the sandstone-shale interval immediately below, and provided an interpretation o.f the 

sedimentary environment. From his description, the 

presence of two potential bluff-forming sandstones 

can he deduced: 

*** The lower 300 feet of this outcrop consists of upward 

coarsening sequences, between 8 and 40 feet thick, composed of shale and siltstones with minor sandstones. Over"-

lying these is a vertical s.equence of eight orthoquartzite 

bodies averaging 10 feet in thickness, separated by silts"tone 

averaging one foot in thickness. The sandstones are both 

massive and low-angle planar cross-bedded and are cut into 

their upper part by channels up to 15 feet deep, which contain bedding types similar to those in the unchanneled portions .... Separated from the top of these sandstones by 50 

feet of silty shale are two superimposed orthoquartzite complexes which clearly illustrate the mutually perpendicular 

relation between the trough cross beds and the long, lowangle planar cross beds. The overlying upward-coarsening 

"bay-fill" sequence of siltstone, with horizontally bedded 

sandstones and a highly carbonaceous shale on top, is capped 

by low-angle planar cross-bedded sandstones*** 

The bluff-forming sandstone, at the top of the 

steep slope, is 47 m thick, massive conglomeratic, 

crossbedded, and contains a few thin shale lenses. 

The rocks over the bluff-forming sandstone are· 

mainly sandstone containing shale beds and are 

about 110 m thick. Imm,ediately over the bluff-forming sandstone one of the shale sequences is about 

12m thick. 

The beds below the bluff-forming sandstone, and 

immediately above the Bangor Limestone, are generally mapped as the Pennington Formation, and 

the beds above thes·e, but still below the bluff-forming sandstone, are mapped as the Gizzard Formation or the lower part of the Lookout Formation. 

The bluff-forming sandstone has been m.ap.ped as 

the Sewanee Conglomerate and the Lookout Sandstone; it has been mapped as Pennsylvanian undifferentiated on the present State geologic map, and 

the rocks above the bluff-forming sandstone have 

been mapped as Walden Sandstone or as Pennsylvanian undifferentiated. 

Several well-developed coal seams are in this 

section; two are above the bluff-forming sandstone, 

called the Tatum and Sewanee seams. The one below the bluff-forming sandstone is known as the 

Cliff seam. All have been mined sporadically, but 

all are discontinuous. 

PENNSYLVANIAN ROCKS ON THE NORTHERN PART 

OF LOOKOUT MOUNTAIN. DADE AND WALKER 

COUNTIES 

This part of Lookout Mountain is northwest of 

the line running northeastward from the narrow 

constriction of Lookout Mountain (figs. 3 and 9) . 

These rocks contain immense reserves of coal and 

have been extensively investigated. Because of the 

incomplete exposures, however, no continuous section is known; the section in figure 9 is a composite-, 

from four different localities. 
GEORGIA H25 

The lowermost rocks were described by Sullivan 

(1942, p. 26) from Johnson Crook (fig. 9, locality 

E) ; they rest upon Bangor Limestone, are mainly 

shal,e, are 123 m thick, and contain s·ome limestone 

beds. They are generally mapped as the Pennington 

Formation. 

Above these are some rocks described by Wanless (1946, p. 24) from the west brow of Lookout 

Mountain just east of Trenton (fig. 9, locality F). 

They are 43 m thick, are mainly gray shales containing, ledge-forming sandstone beds, some very 

pronounced, and have a discontinuous coal seam near 

the top. These have been mapped as the Gizzard 

Formation, as. part of the Lookout Sandstone, and 

as Pennsylvanian undifferentiated on the current 

State geologic map·. 

The bluff-forming sandstone rests upon these. 

Part of this section described above (Wanless, 1946, 

p. 24) fig. 9, locality F) can be seen in the core described by Johnson (1946) from nearby. The bluffform.ing sandstone is very massive, crossbedded, 

channeled, conglomeratic, and coarse-grained quartzose; it is 70 m thick. It has been mapped as the 

W~arren Point Sandstone, the Sewanee Conglomerate, the Lookout Sandstone, the Bon Air Sandstone, and as Pennsylvanian undifferentiated on the 

current State geologic map. 

Above the bluff-forming sandstone are 182 m of 

shale containing beds of sandstone and coal. The 

sandstones are finer grained and are more evenly 

bedded and widespread than those below. The illustrated section is from a core d~scribed by Johnson 

(1946) and from a section measured by Wanless 

( 1946, p. 31). The individual sandstone and shale 

units have been given different names by different 

workers, but th~y have been collectively called the 

Walden Formation or Pennsylvanian undifferentiated (fig. 9, localities G and H). 

The rocks above the bluff-forming sandstone have 

been dated as Medial Pottsville on the basis of 

paleobotany. No fossils are known from the bluffforming sandstone nor from the beds immediately 

below; the beds called the Pennington Formation 

have been dated as Late Mississippian on the basis 

of marine fossils· and regional considerations. 

PENNSYLVANIAN ROCKS ON FOX ·MOUNTAIN, 

DADE COUNTY 

Fox Mountain, the northeastern part of which is 

in Dade County, is a small outlier of the much 

larger Sand or Raccoon Mountain. The rocks are 

preserved in the trough of a syncline, and are the 

least known of the Pennsylvanian rocks of northw.:st Georgia. 

The section illustrated (fig. 9, locality I), is taken 

from McCallie ( 1904, p. 73) and from a field reconnaissance. The rocks above the Monteagle-Bangor 

Limestones are poorly exposed, but app~ear to be 

about 69 m of varicolored shale at the base and gray 

shale toward the top. Limestones are interbedded 

toward the base, and sandstones are interbedded 

toward the top. A thin, relatively persistent coal 

seam is at the top, immediately, under the bluffforming sandstone. 

The bluff-forming sandstone forms the top of the 

plateau. It is medium to coarse grained, very conglomeratic, massive to thin bedded, channeled, and 

crossbedded. It is at least 33 m thick, though the 

top is now here exposed. 

No fossils are known. The age of the rocks below 

the bluff-forming sandstone are proba;bly Mississippian on the basis of regional considerations and 

stratigraphic position. The bluff-forming sandstone 

is probably Pennsylvanian. 

PENNSYLVANIAN ROCKS ON SAND MOUNTAIN, 

DADE COUNTY 

Sand Mountain in Georgia is a ·part of a much 

larger feature known as Sand or Raccoon Mountain in Alabama and Tennessee. The rocks are preserved as the trough of a broad syncline, f.orming 

a plateau, into which ohsequent streams have incised deep valleys. 

The section in figure 9 is composite, from two 

different localities. Most o,f the section is from 

Scratch Ankle Hollow (fig. 9, locality J), actually 

in Tennessee, measured by Wilson (1965, p. 36-38), 

and the lowermost part of the section is from an 

uncertain location identified only as Hooker (fig. 9, 

locality K) by McLemore (1971, p. 221). The 

Scratch Ankle Hollow section contains the type secmuch resemble the upper beds of the Bangor Limetion of the Raccoon Mountain Formation as identified by Wilson, Jewell, and Luther (1956). 

The lowermost 32 m of gray shale in the composite section rests u·pon Bangor Limestone, and 

McLemore referrc·d to these beds as being within 

what he called the Pennington Formation. What 

McLemore considered to be the lower part of the 

Pennington Formation contains beds which very 

much resemble the upper beds of the Bang.or limestone of this report. 

Above the 32 m of gray shale are shale and sandstone beds 106 m thick (Wilson, 1965, p·. 36-38) 

which contain several commercial coal seams. Me-
H26 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Lemore (1971) included some of these rocks within 

what he called the upper part of the Pennington 

Formation in the section which he measured. These 

rocks have been called by others the Lookout Sandstone, Gizzard Formation, Raccoon Mountain Formation (the type section), and the Norwood Cove 

and Flat Rock Formations. One of the sandstones 

in this part of the section thickens and becomes the 

bluff-forming sandstone ·elsewhere on Sand Mountain (Wilson, 1965, p. 28). 

The composite nature of this part of the section 

results in uncertainty about the thickness; the 

Hooker section has an uncertain top, and the Scratch 

Ankle Hollow section has an uncertain base. This 

results in an uncertain amount of overlap in the 

two measurements. Refer.::nce to other published 

sections from nearby (McCallie, 1904; Spencer, 

1893; Troxell1946) show the irregularity of deposition of the beds and why the correlations have· been 

so chaotic. Ferm and others (1972) described the 

sedimentary circumstances under which these beds 

could have been deposited, if true, would explain 

why· the problems are present. 

The bluff-forming sandstone is 39 m thick, massively bedded, conglomeratic, crossbedded, quartz 

sandstone. This has been called the Flat Rock Sandstone, part of the Gizzard Formation, the Warren 

Point Sandstone, the Lookout Sandstone, the 

Sewanee Conglomerate, and Pennsylvanian undifferentiated. 

The beds above the bluff-forming sandstone constitute a shale .sequence about 30 m thick, overlain 

by a conglomeratic sandstone about 3 m thick. The 

sandstone caps the highest hills. on Sand Mountain, 

and is the youngest formation on the mountain in 

Georgia. These rocks have been called the Walden 

Formation, the Signal Point Shale, and the Sewanee 

Conglomerate, respectively. 

Paleobotanically, the coal beds below the bluffforming sandstone contain a flora that is Medial 

Pottsville in age; the beds below these, which rest 

upon the Bangor Limestone, contain Mississippian 

fossils. No fossils are in the rocks above the bluffforming sandstone. 

The coal resources on Sand Mountain are in beds 

below the bluff-forming sandstone, whereas the 

coals on the northern part of Lookout Mountain are 

in beds above the bluff-forming ·sandstone, yet the 

C·Oals are the same age, M·edial Pottsville. 

CORRELATION OF PENNSY.L V ANI AN ROCKS 

It is easy to understand how the twofold subdivision of Pennsylvanian rocks originated (fig. 10). 

Everywhere a similar-appearing, conglomeratic, 

bluff-forming sandstone can he seen at the edges of 

the plateaus, with shale, sandstone and coal underneath, with a distinctly irregular sedimentation pattern, whereas the rocks over the bluff-forming 

sandstone are clearly more widesp-read and continuous in distribution, and can be traced with more 

assurance. 

The bluff-forming sandstone and the irregularly. 

disposed rocks below were called the Lookout Sandstone, and the more uniform rocks above the bluffforming sandstone were called the Walden Sandstone. Later, the rocks below the bluff-forming sandstones were .identified as the Gizzard Formation, 

which contained one sandstone known as the Warren Point; the bluff-forming sandstone was called 

the Sewanee Conglomerate. The Walden Sandstone 

was subdivided into three shale and three sandstone formations. 

As more data were gathered, the bluff-forming 

sandston8 was found not to be the same unit everywhere; the bluffs were being formed by whichever 

sandstone happened to be at the level of erosion. 

Therefore, if different sandstones were found to be 

the bluff-forming sandstone, then the correlations of 

the rocks above and below would have to be altered; 

this accounts for the plethora of terms which have 

been us·ed for the .same rocks. An appreciation of 

the lateral variation in the rocks below the bluffforming sandstone would also influence any decision 

about the correlation of these rocks over long distances. 

Furthermore, correlations in the past have been 

predicated upon the "layer cake" philosophy of 

. stratigraphy, that the units are form·ed as widespread blank·ets and can be correlated on the basis 

of superposition. Rc·sults of modern studies show 

that this concept, particularly for the Pennsylvanian 

of Georgia, is not valid, for the rocks are distinctly 

interfingered and not blanketlike. 

Correlations in the past have been based partly 

on the assumption that the 'Coal beds are widespread 

and that correlation by superposition and (or) 

lithology was possible. Detailed studies show that 

the coal beds are very irregularly disposed and distributed. Caution should be exercised when corrdating the coal seams. 

BIOSTRATIGRAPHY 

Little paleontological investigation of the Pennsylvanian rocks of Georgia has been carried out hecause most of the rocks arc nonmarine and fossils 
GEORGIA H27 

are sparse. Most investigations have been paleobotanical. 

The first published report of fossil plants was by 

Lesquereux (1880-84, p. 852) who listed a flora of 

27 species from an uncertain locality and stratigraphic position in Dade County. Inas.much as mining activity at that time:· was confined to the Etna 

and Dade coal seams, the flora was probably from 

the rocks below the bluff-forming sandstone. He 

correlated this flora with that of the No. XI zone in 

Pennsylvania, which is now called the Mauch Chunk 

Formation, of Late Mississippian age. 

White (1900, p. 817), on the other hand, not·~d 

that the flora of the roof shale of the Dade coal (below the bluff-forming sandstone, and from where 

Lesquereux's flora may have come) was similar to 

the flora of the M ariopfhris pottsvillea zone of elsewhere in the Appalachians; he considered the age 

of this zone to be Early Pottsville, but not the 

earliest. 

White later ( 1943), identified M ariopteris pottsvillea from rocks over the Castle Rock coal seam 

(also known as the Etna seam), im·mediately below 

the bluff-forming sandstone in Dade County; the 

Castle Rock seam i:s a few tens of feet above the 

Dade coal ·seam, which also contains the M. pottsvillea zone flora in the roof shale. 

In the same reference, White (1943) noted Aneimites ten~tifolia difoliatis and A. pottsvillensis var. 

inte1·media in the roof shale over the Durham No. 

5 ·coal seam, above the bluff-forming sandstone on 

the northern part of Lookout Mountain in Walker 

County. These are also Early Pottsville in age, although not the earliest. 

Allen and Lester ( 1954, p. 131-149) listed and 

illustrated a curious flora of 23 species from coalmine dumps o.f uncertain stratigraphic and geographic position, although clearly in rocks above 

the -bluff-forming sandstone. This flora contains 

species that have much older and much younger 

ages than the Eady Pottsville. 

Read and Mamay (1964), .in their work on the 

floral zones of the upper Paleozoic, identified the 

Ma1·iopte1·is pottsvillea-Aneimites spp. zone as the 

No. 5 zone -in their classification. Zone 5 was according to them, Medial Pottsville, or Early New River 

in the terms of Appalachian stratigraphers. 

Wilson (1965, p. 49) suggested that a coal seam 

at the base of the Norwood Cove Formation, the 

base of which he was calling Pennsylvanian, in rocks 

below the ·bluff-forming sandstone, contained spores 

having definite Chesterian (Late Mississippian) 

affinities. 

Wanless (1975, p. 32) concluded that the Pennsylvanian rocks in Georgia are entirely within zones 

5 and 6 of Read and Mamay. He noted the presence 

of elements of floral zone 6 from shale "just above· 

the Sewanee coal on Lookout Mountain". Which 

coal he meant ·by the Sewanee is not clear, although 

in an earlier report (Wanless, 1946), he meant 

that coal which is in the shale immediately over the 

bluff-forming sandstone on .the southern part of 

Lookout Mountain. In a later report (Wan less, 

1961), he implied that all of the coals above the 

bluff-forming sandstone in the northerp. poart of 

Lookout Mountain are the Sewanee, in the sense of 

the Sewanee ·coal basin. If this is so, it would include ·the Durham No.5 seam, the same seam which 

contained. the species of Aneimites noted by White 

(1943) which were included in floral zone 5 by 

Read and Mamay (1964). 

Detailed biostratigraphic correlations based on 

paleobotany cannot be made with certainty at this 

time, but generally the presence of zone· 5 and possibly of zone 6 of Read and Mamay seems reasonable. Zones 5 and 6 are entirely in the Pottsvine Series, Lower Pennsylvanian, although not the 

lowest. These correlate with rocks of Morrowan 

age of the midcontinent region and with rocks of 

Westphalian-A age of Europe. 

Invertebrates from the Pennsylvanian rocks of 

Georgia are rare. Wanless ( 1946, p. 32-33) reported a Lingula-bearing shale from the rocks overlying the bluff-forming sandstone on the northern 

part of Lookout Mountain. 

Molds of imbricated pelecypod shapes are found 

in one of the sandstones exposed in a strip mine on 

Sand Mountain, Dade County, but identification 

other than the suggestion of beach-environment deposition is not possible. 

Brachiopods, fenestrate bryozoans, and crinoiq 

columnals have been found in the thin-bedded, finegrained sandstone unit belo.w the bluff-forming 

sandstone on Little Sand Mountain in Chattooga 

County, above beds commonly considered Pennington Formation, but these fossils have not yet been 

analyzed. 

Brachiopods, pelecypods, gastropods, orthoconic 

cephalopods, and fenestrate bryozoans have been 

found in a carbonatic, arkosic sandstone from rocks 

a~bove the bluff-forming sandstone on Rocky Mountain, but these are not well enough preserved· for 

positive identification. 

Limestones, which, if present, would not only be 

a potential source o.f marine invertebrates, but 

would make splendid marker 'beds for the maps in 
H28 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

this otherwise clastic-rock terrane, are rare. Only 

two have been identified, and neither investigated; 

both are thin and appar·ently not widespread. 

Spencer ( 1893, p. 252) noted a seam. of limestone in 

the shale unit 3.07 to 5.2 m above a coal bed, later 

to he known as the No. 4 coal, on Lookout Mountain, 

Walker County. M·cCaHie (1904, p. 41) failed to 

find this rock, and Wanless (1946, p. 32) reported 

a covered interval which included the limestone at 

that part of his measured section. 

Anothe·r limestone, at least 0.6 m thiok, was reported in one of the cores made by the Georgia 

Power Co. en Rocky Mountain. It is in the rocks 

above the bluff-forming sandstone; this has not been 

investigated. 

DEPOSITIONAL AND TECTONIC FRAMEWORK 

PAST INTERPRETATIONS 

The first comprehensive study of Pennsylvanian 

rocks in Georgia, tha:t of McCallie (1904), does not 

contain any geological background for the origin of 

the rocks or of the coals. 

The first dis-cussions of the rocks and coals were 

included in the report of Wanless (1946, p. 129) in 

which the Pennsylvanian rocks of the entire southern Appalachian Moun'tains were described. He 

sp.eculated upon cyclothemic deposition, so common 

in the rocks of the midcontinent area, and concluded that: 

*** a sort of rhythmic sequence is frequently repeated *** 

This begins with a massive basal siltstone or sandstone, unconformable on underlying strata. The sandstone grades up 

into siltstone or sandy shale, and the shale may contain 

sandstone partings and fossil plants. The siltstone is followed by an underclay which is often divided by shale or 

siltstone and may have siltstone or sandstone at the top. The 

coal zone follows, and often includes several be·nches of coal 

spread through an interval of as much as 20 feet. The coal 

zone is overlain by shale which is generally plant bearing 

in the immediate roof and which may contain ironstone or 

occasionally impure limestone bands or concretions and may 

yield fresh- or brackish water fauna and rarely a marine 

fauna. This may grade up into sandy shale and siltstone 

to the next higher sandstone, or the sandstone may cut out 

part or all of the shale and rest on the coal, or even cut 

out the coal. 

There are many ·resemblances between the rhythms *** 

here and the cyclothems*** the differences being the obvious 

results of differences in environment and rates of sedimentation. 

***The Warren Point, Sewanee, Herbert, Newton, Rockcastle*** sandstones are all basal members of such sequences 

***at least a considerable part of the sediment was derived 

from the east or southeast. 

Certain districts seem to have been near the points of 

discharge of large rivers carrying sandy or gravelly sediment. 

He further noted (Wanless, 1946, p. 131): 

The sediments all seem to have formed in aqueous environments which include piedmont, valley flat, marsh, lake, delta, 

lagoon, and shallow sea-floor environments. Even the coarsest 

sediments are too well sorted with too nearly horizontal 

bedding surfaces and are too extensive to suggest a piedmont 

environment adjacent to high uplands*** The coals are 

evidently of a marsh environment*** 

***A widespread delta plain fronting the sea, with a network 

of delta lakes, marshes, and lagoons and shifting channels 

of discharge for the streams seems the most likely type of 

environment. 

As regards the tectonic setting, Wanless concluded (194·6, p. 132) : 

Adequate sedimentation pr.evailed during the deposition 

of the coal measures of the southern Appalachian field. *** 

[excess sediment was bypassed to a more distant locality] 

*** If thi:s assumption is correct, the amount of sediment 

deposited during a particular interval is a measure of the 

amount of downwarping. The southeastern border of the coal 

field [including northwest Georgia] was downwarped several thousand feet more than the region of Ohio *** and the 

rate of downwarping increased southeastward at a uniform 

rate. 

He showed that the basins of deposition formed 

during the Pottsville, and that great changes in 

thickness take place within short distances, such 

as that between the rocks under the bluff-forming 

sandstone in Sand Mountain and the northern p_a.rt 

of Lookout Mountain. Milici ( 197 4) named the Raccoon Mountain basin as the depositional center for 

the thick section of rocks under the bluff-forming 

sandstone on Sand Mountain. 

Wanless' pioneer work was followed by many 

studies and interpretations of the sedimentary petrology of the sandstones, mostly of those on the 

northern part of Lookout Mountain. Renshaw 

(1951) recognized deltaic and beach :sedimentation, 

and Allen (195:5) and Albdtton (1955) identified 

tida:l-flat sediments. 'r.he latter writer also speculated 

upon a southeastern source for the sediments. Shotts 

(1957) showed that the coals on the southern part 

of Lookout Mountain are in discrete basins, and 

that they are separated from one another by what 

he called deltaic variations in .sedimentation. 

Tanner ( 1959) first noted, from crossbedding 

studies, that Pennsylvanian rocks were deposited by 

currents that were more toward the south than toward the north ; he suggested a shoreline toward 

the north-northeast. Schlee ( 1963), also, after crossbedding studies, concluded that the Pennsylvanian 

sandstones are mainly from a fluviatile environment 

and that the predominant transport direction w·as 

toward the southwest. He .suggested that the sandstones are .from sands deposited on flood plains or 
GEORGIA H29 

in estuaries, and that they are the result o.f sheets 

of anastomosing linear sand bodies. 

Chen and Goodell (1964) studied the petrography 

of the bluff-forming sandstone on both pa.rts of 

Looko~t Mountain. They found provenance to have 

been mainly a crystalline-rock terrane, and the direction of regional transport to have been to the 

southwest. They suggested a paludal or marginalcontinental environment fo·r the sandstones. 

Wilson ( 1965) believed that the Pennsylvanian 

rocks on Sand Mountain wer·e of terrestrial origin, 

and saw no clear evidence for the marine origin suggested by Wilson and Stearns (1960). He interpret:d provenance as having been highlands to the 

east or northeast, with small amounts of the sediments possibly having come from as far away as 

the Canadian Shield. The coals are from freshwater 

swamps. Boron-trace studies support this interpretation. 

The volume on Pennsylvanian paleotectonics of 

the United States (McKee and others, 1975), the 

summation of Pennsylvanian stratigraphy to that 

date, includes much data about the rocks in Georgia. 

They were deposited in a basin with the· source of 

the sediments having been to the ·east and northeast, 

and with the provenance having been a series of 

w,:Jts of mountainous islands, like those which flank 

the Pacific basin today. The conglomerates, sandstones, and mudstones form a series. of detrital 

wedges. In some areas, sand and mud accumulated 

without much interruption, but elsewhere, deposition of d::.1tritus ceased periodically, and coal beds 

resulted. The sea is believed to have transgressed 

periodically from the southwest. Cyclic sedimentation is plainly evident, but cyclothemic conditions 

are less uniform r'.:gionally. 

Coarse sediment entered the App·alachian basin, 

including Georgia, several times during the deposition of Pottsville sediments, a result of erosion and 

sedimentation caused by contem.poraneous tectonism. Whether the alternations between the 

coarse, conglomeratic sandstones, clay, and coal 

beds resulted from intermittant renewal of tectonism or from -climatic changes cannot be dotermined from the exposures in Georgia. 

The above review of the data and the interpretation shows no unequivocable explanation for the 

sedimc:ntary environment or tectonic setting for the 

Pennsylvanian rocks of Georgia. The rocks are 

neither unquestionably marine nor unquestionably 

terrestrial. 

CURRENT INTERPRETATIONS 

More recent investigations of the Pennsylvanian 

rocks in the Appalachian Mountains· in general, and 

in Alabama and Tennessee in particular, have allowed for interpretations which take into account 

the uncertainties outlined above-an environment 

between t}1e marine and the terrestrial, that o.f the 

littoral zone, the barrier-island complex, and the 

lower-delta plain. 

During the time that the Pennsylvanian paleotectonics volume was heing prepared, new ideas regarding the interpretations of the Appalachians 

around Georgia were fermenting. John Ferro and 

his associates and students identified possibl~ depositional environments for the Pennsylvanian rocks 

of Georgia and vicinity. 

The current interpretations were initiated by 

Stearns and Mitchum (1962) who applied isopach 

and lithofacies studies to a regional stratigraphic 

analysis of the Pennsylvanian of the southeastern 

United States. They noted a belt of high-sand ratios 

which pass·ed through Georgia, subparallel to the 

present outcrop patterns, and trended northeast. 

They suggested no explanation, but it is possible 

that .. these belts of high-sand ratios were roughly 

parallel to the paleoshorelines and that they could 

have resulted from. barrier-island complexes. Considerable evidence now supports this interpretation. 

In many oplaces, particularly along the western 

brow of the northern part of Lo,okout Mountain, 

the bluff-forming sandstone is massively bedded, 

crossbedded, conglomeratic, channeled, and quartzose. The crossbedding is in ·channels, p.Janar, and 

trough-like, such as would .be expected in a barrierisland complex environment .. 

In other places, the bluff-forming sandstones are 

not as massive or conglomeratic; these could be preserved from other parts of the b~rri€r-island complex, such as tidal deltas, washover fans, or dunes. 

The dark-gray shales and bedded .sandstones which 

accompany the more massive sandstones could be 

from .barrier-island mars:hes., which were occasionally invaded by the sea or from washover fans or tidal 

fans from the seaward side, or from terrestriallyderived detritus from the landward side, such as 

flood plains. ·coal could form when these marshes 

were filled to sea level and a soil could form ; if the 

environment would not support v.egetation, ironston~ · could precipitate. An environment such as 

this·· would explain the irregular distribution of the 

coal and the sandstones, and the frequent intimate 

mixing of them. 
H30 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Milici (1974) and Ferm and others (1972) recognized, for instance, from, nearby Tennessee and 

Alabama, rocks from the littoral environment. The 

coal-bearing sandstone and shale (the Racoon Mountain Formation), from beneath the bluff-forming 

sandstone are from lag:oon complexes that formed 

behind barrier bars. Tidal deltas, washover fans, 

and beach deposits are also part of this complex, 

and the sandstones from these features are interdigitated with the coal-bearing, shaly, lagoon deposits. The shifting of the strand line, whether 

tectonic or eustatic, resulted in blanket-sandstone 

deposits (the bluff-forming sandstone) as the bars 

migrated over the marsh deposits to follow the 

strand line. 

The interpretation that these rocks were deposited 

in a littoral environment provides an explanation 

for the correlation chaos; the various units, sandstone, conglomerate, shale, coal, and others, are all 

interfingered rather than being superimposed. The 

coals and siderite layers result from a stillstand of 

the .sea when the lagoons were filled to sea level so 

that they could supprort the coal-producing vegetation or ironstone-forming conditions. 

Thomas (1972a), in a report on the Mississippian 

rocks of Alabama, recognized that the rocks lying 

athwart the Mis·sissippian-Pennsylvanian boundary, 

in part those below the bluff-forming sandstone, are 

the result of similar depositional environments. The 

littoral environment prograded southw·estward, 

bringing clastic sediments into and onto. the carbonate shelf. Although his discussion does not includ8 Georgia, it could clearly be extrapolated to include the State. Marine rocks are overlain by intercalated clastic rocks of marine and littoral origin. 

The alternation of marine and littoral environments 

resulted from strand-line fluctuations throughout 

the interval. 

Thomas' thesis, of a southwc~stward-prograding 

clastic lithosome, was supported by the observations of Ferm (1974) who, in speculating about the 

sedimentary similarities between the Carboniferous 

rocks of eastern North America, western Europe 

and Africa, sugg.ested that a landmass somewhere 

in the North Carolina area shed sediments outward 

in all directions. Sediments coming to the Georgia 

area would have been from a metamorphic terrane, 

as indicated by the ·petrologic studies, and from the 

northeast, as suggested by the textural and structural studies. 

Hobday (1974) believed that some of the Pennsylvanian rocks of Georgia were deposited in a 

littoral environm·ent. His studies of one of the 

orthoquartzite bodies in the section near Cloudland, 

the one forming the lower bluffs (fig. 9, locality D) 

on the southern part of Lookout Mountain, show it 

to be a deposit of a barrisr island. The associated 

shale and coal originated in relation to this feature. 

The sedimentary features that distinguish the 

rocks over the bluff-forming sandstone from those 

under it on the northern part of Lookout Mountain 

and on Sand Mountain, Dade County, were noted 

as .early as 1892 by Hayes ( 1892, p. 50) who used 

this distinction to create the first subdivisio~ of the 

Pennsylvanian rocks of Georgia. He noted : 

"These upper rocks [those over the bluff-forming 

sandstone], embraced under the name Walden, are 

more homog·eneous than the Lookout [the bluffforming sandstone and the rocks under it] and show 

marks of fewer abrupt changes in conditions o.f sedimentation." 

This same difference was noted by Wanless 

(1961) when he discussed what he called the 

Sewanee coal basin. Although his text did not clearly indicate which ~coal he meant, the environment 

of deposition that he discussed for the basin was 

clearly for rocks overlying the bluff-forming sandstone on the northern part of Lookout Mountain. 

He noted the persistency of thes·e units over large 

areas, and ·showed the relations of the$e deposits to 

deltaic s·edimentation. The regional correlations were 

based on the flora of the roof shales of some of the 

coals. He suggested that the basin persisted for the 

time that several of the coals were deposited, and 

not just one of them. 

The coal deposits on the northern part of Lookout 

Mountain, those above the bluff-forming sandstone, 

seem to have a different character from those below 

the bluff-forming sandstone elsewhere. The coal 

seams themselves, and the enclosing shales and 

srandstones, are much more laterally continuous., reflecting a greater geographic area for the depositional environment, and one which was more 

stable over a longer time than one closer to sea 

level, where strand-line fluctuations would be reflected in the changes in sedimentation. The thickness of the coals also support the interpretation of 

a more stable long-lived environment. Such an environment would be found on the delta plain, behind and inland to the littoral, offshore-bar environment. 

Therefore, if the tectonic-sedimentation regime 

which began in the Mississippian, of deltaic progradation over a carbonate sequence, were to have 

continued into the Pennsylvanian, the resulting 

vertical sequenc·e of rocks to be expected over the 
GEORGIA H31 

open-m-arine rocks would be prodelta and deltafront clastic ·-rocks, which in turn would be overlain by deposits of barrier-bar complexes and barmarsh deposits, which in turn would be overlain by 

delta-plain deposits. in which the coal seams would 

be thicker and more widespread. 

As this appears to be true in Georgia, the systemic boundary between the Mississippian and 

Pennsylvanian must be in the com.plex of clastic 

rocks between the Monteagle-Bangor Limestones of 

unquestioned Miss.issippian age and the ov£rlying 

clastic rocks that contain a Pennsylvanian flora. 

MISSISSIPPIAN -PENNSYLVANIAN BOUNDARY 

PROBLEM 

The boundary between Mississippian and Pennsylvanian rocks in Georgia has commonly been assigned to designated marker beds of some description such as at the top. of the highest maroon mudstone, below the low.est c·oal bed, at the base of the 

massive bluff-forming sandstone, or at the base of 

the lowest quar~z-pebble-bearing sandstone. Although the Mis,s.issippian-Pennsylvanian systemic 

boundary is by definition a time-stratigraphic horizon, the criteria by which it has been identified in 

Georgia have been rock-stratigraphic. 

F.ossils in the limestone sequence establish a 

Mississippian age, and plant fossils demonstrate a 

Pennsylvanian age in the coal above· the massive 

sandstone. The horizon of the M·ississippian-Pemnsylvanian boundary must be within the lithofacies 

transition beds between .the limestone and the coalbearing sequence, and the systemic boundary has 

commonly been placed at the contact between the 

Pennington and Raccoon Mountain Formations 

(Culbertson, 1963; Wilson, 1965, p. 47; Milici, 1974, 

p. 118). That -contact traditionally has been considered to be a regional unconfor·m.ity (Culbertson, 

1963, p. E56), but recent work indicates that the 

succession is gradational except locally where sandstone at the :base of the Raocoon Mountain rests on 

a scoured surface (Milici, 1974, p. 121). Lack of 

detailed biostratigraphic data from this part of the 

section precludes precise identification of the boundary. Spores from a coal bed in the Raccoon Mountain Formation of Alabama have "definite Chesteri·an affinities" (Wilson, 1965, p. 49), and invertebrate fossils from Raccoon Mounta·in equivalents in 

Alabama are Mississippian (Milici, 1974, p. 118). 

Possibly the systemic boundary is within the Raccoon Mountain Formation. 

The rock succession in Georgia suggests continuous sedimentation during deposition of a prograding ·clastic sequence (fig. 11). The succession above 

the Mississippian carbonate sequence grades up.ward 

from m·arine and near-shore mudstone to massive 

barrier and (or) delta-front sandstones. The interpretation that the strata reflect prograding sedimentation implies the identifi·cation of time-stratigraphic planes acros·s temporally equivalent facies 

(fig. 11). Identification of the systemic boundary 

awaits resolution of a maze of biostratigraphic and 

lithostratigraphic details. 

MINERAL RESOURCES OF THE 

CARBONIFEROUS ROCKS 

COAL 

The most valua:ble mineral deposit in the Carboniferous rocks of Georgia is bituminous coal; it 

is still being mined after more than 100 years. The 

first mining took place in Dade County in 1854. In 

1891, the first ·coal was taken from Walker County 

on Lookout Mountain, and after 1892, when the railroad arrived at Durham, production increased dramatically. By 1900, all of the coal from Georgia was 

coming from the Lookout Mountain field in Walker 

County except for one mine still operating on Sand 

Mountain, .in Dade County. The peak year of pr<;>-

duction was 1903, when 417,000 short tons we·re 

taken, mostly from the Durham No. 5 coal. 

In 1920, strip ·mining was introduced to Georgia, 

and sporadic production continued. Production 

again increased during World W·ar II, but declined 

steadily after that, and has .been negligible for many 

years. Currently, production has again increased 

dramatically. 

FIGURE 11.-Hypothetical 1stratigraphic cross section of rocks near the Mississippian-Pennsylvanian boundary in northwest 

Georgia. Heavy dashed line shows interpreted position of a time-stratigraphic line. 
H32 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Production o.f coal from Georgia, by quintade, is 

shown in figure 12, and the reports of McCallie 

(1904) and Johnson (1946) remain the most complete sources of information to· date. 

Coal seams.-Many seams o.f coal have been 

mined, and there is much confusion about the correlation of the various seams. The same name has 

been .given to clearly different seams, and the same 

seam has been given different names. As a result, 

the information derived from the literature is hard 

to evaluate. 

On Sand Mountain, aU of the coals from Georgia 

are .in the rocks below the bluff-forming sandstone; 

those above have not yet been developed if they 

exist. Two well-known seams are the Castle Rock, 

or Etna Beam, and the Dade seam. The name Etna 

is generally used for the coal immediately under 

the bluff-forming sandstone and the Dade seam is 

about 10 m below the Etna. The other seamsRattlesnake, Red Ash, Mill Creek, Cliff, and New 

England, are irregular and discontinuous, and all 

are subject to miscorre1lation. The seams reach thicknesses of more than 2 m, but most are much thinner 

than 1m. 

The coals on the northern part of Lookout Mountain are much better known and have been more 

fully exploited than those on Sand Mountain. Three 

prominent coal seams are an uppermost A seam, 

rn 

c: 

Q) 

Q. 

0 

c: "iii 

E 

::l "C 0 ('I) 

2000 ~ !Xi ~ s 5 ~ 

1800 ~ 0 c: 0 0 0 

...J c: 

1600 "iii 

E 

::l 

0 

1400 ~ 

c: s 

1200 .Q ~ :a 0 Q) 0 

Q. ...J 

1000 Q) 

0 = c: ... 800 -~ IU 

~ 3: 

600 E ~ 

<( 0 

3: <a 400 "€ 

Q) 

"C 

200 .... ~ II= N c: ..... ~· ~ 0 0 8 

FIGURE 12.-Graph showing coal production (given in thousands of short tons) in Georgia for 5-year intervals from 

1860 to 1977. 

the Durham No. 5 seam a few tens of meters below 

the A seam, and the Durham No.4, or Tatum seam, 

about 15m below the Durham No.5. All are above 

the bluff-forming sandstone. A thin, discontinuous 

coal seam is immediately below the bluff-forming 

sandstone called the Cliff, or Castle Rock seam. All 

the coals have been mined at one time or another, 

with the No. 5 being the biggest single producer. 

All have been called the Sewanee coal seam in the 

literature. 

On the southern part of Lookout Mountain above 

the bluff-forming sandstone are two coals seams 

which have been extensively mined. The uppermost 

one is the Tatum seam, with the Sewanee seam a 

few tens of meters below it. The Sewanee seam is 

known to be as much as 2 m thick, but is usually less 

than a meter. A thin, discontinuous zone of coals 

is immediately below the bluff-forming sandstone. 

These coals are called the Cliff seams No. 1 and 

No. 2, or the upper and lower Cliff coals. They have 

also been called the Etna and (or) Castle Rock 

seams. All of the coals on the southern part of 

Lookout Mountain are being mined today in one 

place or another; none is everywhere p·resent, 

however. 

Coal reserves.-The figures for the reserves of 

coal in Georgia have varied considerably. The differences in the figures reflect not only changes in 

the techniques of reserve calculations, hut differing 

interpretations of the correlations of the coals. 

Table 1 shows the reserves as calculated in different 

years. 

TABLE 1.-Coal reserves, Georgia, 1907-74 

Original Rem8:ining 

Date Source [~rfli~~ss ~~~~~~s Rema·rks 

of short tons) of short tons) 

1907 __ Campbell, 1908 933 921 

1942 __ Peyton, 1942 400 Unpublished 

data. 

1942 __ Sullivan, 1942 188 184 Sand Mountain 

only. 

1946 __ Johnson, 1946 24 

1948 __ Gildersleeve, 1948 206 120 In Butts and 

Gildersleeve, 

1948. 

1948 __ Peyton, 1948 115 Unpublished 

data. 

1960 __ Averitt, 1961 100 76 Average of 

others. 

1967 __ Averitt, 1969 24 18 

1974 __ Averitt, 1975 84 78 Includes hypothetical possibilities. 

1974 __ Averitt, 1975 1 Demonstrated 

reserve base. 
GEORGIA H33 

T·he figure of 1 million tons, currently quoted, is 

a product of a conservative formula, the Demonstrated Reserve Base, designed to allow comparison 

of coal reserves fro·m different areas. It .is baSed 

upon the reserves in beds 24 or more inches thick, 

less than 1,000 feet deep, and economically exploitwble .in 1974. Not much Georgia coal falls into this 

tightly restr.icted ·cate-gory, hence the low figure. 

Coal 'rank and chemistry.-Table 2 shows published cumulative analyses .of ·Geo·rgia coals. All the 

coals are medium-volatile bituminous on the table, 

but individual coal analyses include much low-volatile bituminous coal. 

Because of the problems of coal-seam correlation, 

much confusion probably exists in the identity of 

the coals cited in the table. Also, the variation in 

the analytical quality is considerable. Some are the 

averages of a few tens of analyses, and some are 

average for as few as three. 

All the coals, except for a few that have very 

distinctly different analyses, are low in sulfur. Many 

other trace-element studies have been made on 

Georgia coals, the results of which may be found in 

Stadnichenko and others (1961), Walker and Hartner (1966), and in Zubovic and others (1966). 

CLAY AND SHALE 

C~ay and shale are actual and potential mineral 

resources from the ·Carboniferous rocks of Georgia. 

T.he underclays of the Pennsylvanian terrane have 

been tested for their fi·re-brick potential, and none 

is useful for that, although they test well for general ceramic properties. Inacessibility prevents 

their being deve·loped at this time. 

Shale in the Pennington and Floyd formations of 

Mississippian age is being used for ceramic products 

and po·rtland ·cement; most comes from the Floyd 

formation. None that has· been tested is suitable 

for whitewear or bloating. Smith (1931) and McLemore (1971) provide numerous analyses and deTABLE 2.-Proximate analyses and sulfur content of Georgia 

coals, in percent 

Coal H~o Volatile Fixed AS'h Sulfur matter carbon 

Cliff ----------- 1.7 21.1 70.5 8.1 2.0 

Dade ---------- 2.5 23.9 63.4 11.4 .9 

Red Ash -------- 4.8 23.9 70.2 4.4 1.3 

Etna ----------- 2.6 26.3 66.8 5.3 1.8 

Rattlesnake ---- 3.8 24.6 65.0 9.3 1.1 

Durham 4 ------ 2.8 20.2 72.1 5.4 .7 

Durham 5 ------ 2.4 20.0 72.5 5.5 .9 

A -------------- 2.6 20.2 61.6 18.1 2.1 

Sewanee ------- 2.9 18.1 65.6 13.5 1.0 

scriptions of clay and shale deposits from the Carboniferous rocks of Georgia. 

BUILDING STONE 

Some crossbedded sandstones in the Pennsylvanian have been used for flagstone (Sullivan, 

1942), as has the so-called Hartselle Sandstone on 

Lookout Mountain (U.S. Geol. Survey and U.S. 

Bur. Mines, 1968, p. 200-201). This latter unit 

is more likely a Pennsylvanian sandstone. 

Burns (1892, p. 899) wrote of the Millstone Grit 

on Lookout Mountain, presumably the bluff-forming 

sandstone, and pointed out its value· as a potential 

source of millstones. The market for these is depressed at the mom:ent. 

LIMESTONE AND DOLOSTONE 

All the limestone and dolo-stone resources of the 

Carboniferous rocks of Gc.orgia are from the Mississipp-ian. Cement limestone is taken from parts of 

the Monteagle-Bangor facies. and from one of the 

limestone tongues in the Floyd Shale. Numerous 

other quarries provid2 limestone for aggregate, 

most of which also comes from the MonteagleBangor; a little comes from the cherty Tuscumbia 

Limestone. A small amount of M'ississippian limestone is used for aglime, and one quarry provides 

fluxstone. McLemore (1971) provides a review of 

the limestone and dolostone resources of the Mississippian rocks. 

CHERT 

Chert is found in great abundance in the weathered parts of the Fort Payne and Tuscumbia terranes, and is us:d for aggregate and road metal 

locally. 

SLATE 

In Polk County, the Floyd Shale has been metamorphosed to slate and is exposed in a few of the 

slices in the overthrust belt. It has been taken in 

the past along with the much more abundant Rock-. 

mart Slate, of Ordovician age. Cressler (1970) gives 

the details. 

GROUND WATER 

Northwest Georgia in .general has a good supply 

of ground water, sufficient for most domestic needs, 

but the rugged topography of the Carboniferous 

terrane 'Precludes the possibility of obtaining large 

supplies for commercial development ( Schneid~r 

and others, 1965). Precipitation is between 132 and 
H34 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

152 em per year, and Wyrick (1968) shows groundwater flows of 0-73,000 liters per day per square 

kilometer. The maximum yield of ground water, in 

liters per minute per day is 379 to 1,137 for Sand 

Mountain, and 1,137 to 2,274 for Lookout and 

Pigeon Mountains. Croft ( 1964) and Cressler 

( 1963; 1964a b; 1970) provide the details about the 

ground water, of the Carboniferous terrane. 

SCENIC FEATURES 

Many scenic features have already been set aside 

for pub He enjoyment and recreation on the Carboniferous terrane, and even more are possible candidates for such development. The sandstone-capped 

plateaus have deep canyons cut into them by the 

ohsequent streams draining them. Cloudland Canyon State Park is one such feature (just north of 

locality G, fig. 9). DeSoto Falls State Park, southward on the same mountain .in Alabama, is a similar feature, and many others could also be developed 

as parks and scenic areas. 

Rock City is an attraction formed from jointseparated blocks of the bluff-forming sandstone on 

the northeastern bluff of Lookout Mountain. 

Many caves have been formed in the Mississippian 

limestone below the ,bluff-forming sandstone that 

forms the cap rock of the plateaus ; some of the 

caves may be developed commercially. Included in 

these is Ellison's Cave, on the eastern flank of 

Pigeon Mountain; this cave is the largest in Georgia 

and contains one o.f the largest vertical pits in the 

world. 

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H36 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

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The Mississippian and Pennsylvanian 

(Carboniferous) Systems in the United StatesAlabama and Mississippi 

Mississippian Stratigraphy of Alabama 

By WILLIAM A. THOMAS 

Pennsylvanian Stratigraphy of Alabama 

By W. EVERETT SMITH 

Carboniferous Outcrops of Mississippi 

By ALVIN R. BICKER, JR. 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1110- I 

Prepared in cooperation with the Geological Survey 

of Alabama and the Mississippi Geological, 

Economic and Topographical Survey 

Historical review and summary of areal, stratigraphic, 

structural, and economic geology of Mississippian and 

Pennsylvanian rocks in Alabama and Mississippi 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1979 

MISSISSIPPIAN STRATIGRAPHY OF ALABAMA 

CONTENTS 

Page 

Abstract ----------------------------------------------------------------- Il 

Introduction ------------------------------------------------------------- 1 

Mississippian lithofacies -------------------------------------------------- 3 

Evolution of stratigraphic nomenclature ----------------------------------- 5 

Lithostratigraphy -------------------------------------------------------- 8 

Maury Shale --------------------------------------------------------- 8 

Fort Payne Chert ---------------------------------------------------- 8 

Tuscumbia Limestone ------------------------------------------------- 8 

Monteagle Limestone ------------------------------------------------- 9 

Bangor Limestone --------------------------------------------------- 9 

Floyd Shale --------------------------------------------------------- 10 

Pride Mountain Formation and Hartselle Sandstone -------------------- 10 

Parkwood Formation ------------------------------------------------- 12 

Pennington Formation ____ ---- _____ ------ __ _ __ __ _ _ _ __ ___ _ _ __ _ _ _ _ _ _ _ _ _ _ 13 

Biostratigraphy ---------------------------------------------------------- 13 

Base of Pottsville and problem of Mississippian-Pennsylvanian Boundary ----- 15 

Depositional and tectonic framework -------------------------------------- 17 

References cited ---------------------------------------------------------- 21 

ILLUSTRATIONS 

Page 

FIGURE 1. Outline geologic map of Alabama ------------------·-------------------------------------------- 12 

2. Diagrammatic stratigraphic cross sections of Mississippian rocks in Alabama --------------------- 4 

3. Generalized isopach and facies maps of parts of Mississippian System in Alabama ---------------- 5 

4. Chart showing evolution of stratigraphic subdivision and nomenclature of Mississippian rocks in 

Alabama -------------------------------------·-------------------------------------------- 6 

5. Generalized lithofacies and paleogeographic maps of Mississippian rocks in Alabama ------------- 16 

III 
THE MISSISSIPPIAN AND PENNSYLVANIAN (CARBONIFEROUS) SYSTEMS 

IN THE UNITED STATES-ALABAMA AND MISSISSIPPI 

MISSISSIPPIAN STRATIGRAPHY OF ALABAMA 

By WILLIAM A. THOMAS 1 

ABSTRACT 

Mississippian rocks in Alabama are exposed along the 

Appalachian fold and thrust belt and extend through the 

Black Warrior basin and East Warrior platform northwest 

of the Appalachians. The lower part of the Mississippian 

System is an extensive unit of chert and cherty carbonate 

(Fort Payne and Tuscumbia); the upper part includes three 

different facies. In north-central Alabama, the upper part 

of the Mississippian is a shallow-marine limestone facies 

(Monteagle and Bangor). On the southwest, the carbonate 

facies is bordered by a northeast-prograding sequence of 

prodelta mud and deltaic sand and mud (Floyd and Parkwood). Tongues of the clastic facies pinch out northeastward 

into the carbonate facies. The most extensive tongue of shale 

and sandstone (Pride Mountain and Hartselle) extends from 

the lower part of the clastic facies and grades northeastward 

into the Monteagle Limestone on the East Warrior platform. 

The upper part of the clastic facies grades northeastward 

into the Bangor Limestone near the southwest edge of the 

East Warrior platform. The Mississippian SySibem thickens 

southwestward in the clastic facies off the East Warrior plat- t 

form and is thicker in Appalachian synclines southe.ast of 

the platform. Where the section is thick in Appalachian 

synclines, the clastic facies (Floyd and Parkwood) progrades 

over the Bangor Limestone and extends much farther northeast than on the East Warrior platform. In northeastern 

Alabama, a southwest-prograding clastic facies (Pennington) grades southwestward into the upper part of the 

Bangor Limestone. Both the northeast-prograding FloydParkwood clastic facies and the southwest-prograding Pennington Formation grade upward into massive sandstones of 

the Pottsville Formation, and the Pottsville extends over the 

Bangor Limestone in north-central Alabama. Although the 

Mississippian-Pennsylvanian boundary is not precisely defined, the Pottsville is commonly consider.ed to be Pennsylvanian. 

Distribution of thickness and facies of Mississippian rocks 

in Alabama define the Black Warrior basin and East Warrior platform. Greater thickness and extent of the northeast-prograding clastic facies indicate contemporaneous Ap~ 

palachian .synclines southeast of the East Warrior platform. On a more regional scale, the northeast-progr~ding 

Floyd-Parkwood sequence is at the eastern limit of a major 

clastic wedge centered on the Ouachita structural salient, 

1 Department of Geology, Georgia State University, Atlanta, Ga. 30303. 

and the southwest-prograding Pennington sequence is at 

the southwestern fringe of a clastic wedge centered on the 

Tennessee Appalachian structural salient. The large-scale 

clastic wedges converged on the Mississippian carbonate 

facies in the Alabama Appalachian structural recess. 

INTRODUCTION 

In northern Alabama, Mis.si:ssioppian rocks are 

expos,ed in :a wide outcrop area along the north limb 

of the Black W arr:ior basin and have been drilled 

in the subsurface beneath Pennsylvanian rocks 

throughout the basin (fig. 1) . The north lim.b of 

the Black Warrior basin is a homocline of low dip, 

and the basin is bordered on the southeast by the 

Appalachian fold and thrust belt. The eastern part 

of the Black Warrior .basin is defined as the East 

Warrior -platform ('f,homas, 1972-a, p. 5). 

In the Appalachian fold and thrust :belt, Mississippian rocks are ex·posed in narrow linear outcrops 

along Appalachian structures, including both limbs 

of the Sequ:atC!hie anticline; the northwest limbs of 

the Birmingham anticlinorium, Murphree Valley 

anticline, and Wills Valley anticline; both limbs o.f 

the Blount Mountain and Lookout synclines; the 

northwest limb of the Cahaba syncline (southeast 

limb of Birmingham anticlinorium); the northwest 

lim.b of the Coosa synclinorium ; and the Coosa deformed belt along the southeast limb of the Coosa 

synclinorium (fig. 1). Farther southeast in the Piedmont province of Alabama, some metasedimentary 

rocks are o.f Mjssissippian age (Carrington, 1967, 

p. 26; 1972, p. 1-18). 

Toward the west and southwest both in the Black 

Warrior basin and along Appalachian structures, 

Paleo~oic rocks plunge southwest beneath the cover 

of Mesowic strata in the ·Gulf Coastal Plain (fig. 1). 

In the subsurface (below Mesozoic coastal-plain 

beds) of western Alabama, the nor:thwesternmoSit 

11 
12 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

·., 

I • 

I • 

I 

' I 

'•A I I 

I 

I 

I

' BLACK 

WARRIOR 

BASIN 

-?-v-!-v-A I 

I 

I 

I 

I 

I 

~d 

I ... 1 .. 

I ·. 

' •• EAST WARRIOR 

\ :PLATFORM 

1: \ 

\~ ~.~ 

\~ 

41~rn." · · · . <:~lf1 Of A11 • • • • • • • • • 

'"1eso · • • • zo,c coastal . . •. . -p/am strata 

MVA MURPHREE VALLEY ANTICLINE 

BMS BLOUNT MOUNTAIN SYNCLINE 

COB COOSA DE.fORMED BELT 

I 

' \ 

\ 

\ 

\ 

.. ' ·' ... 

' , 

( 

' ' 

' I 

J 

\ 

I 

, 

I 

"\ . 

' 

\ 

,------· --------------- ______ . _____ _j' / 25 50 75 100 KILOMETERS 

' . 

,, I 

I 

I 

N 

t 

EXPLANATION 

---..---- Thrust fault 

• - • --; - Anticline 

Metamorphic boundary (subsurface) 

~--- Southwest edge of 

East Warrior platform 

FIGURE 1.-0utline geologic map of Alabama. End points of cross sections of figure 2, are indicated by dots (A-A', B-B', 

C-C'). Outcrop of base of Pennsylvanian is shown only in area northwest of Appalachian foid and thrust belt. 
MISSISSIPPIAN STRATIGRAPHY OF ALABAMA 13 

Appalachian structure is the Pi·ckens-Sumter anticline (fig. 1), and the subsurface fold and thrust 

belt includes at least two other major structures 

(Thomas, 1973). 

The descriptions and interpretations sum·marized 

here are based on measured outcrop sections from 

each of the outcrop belts and on data (sample descriptions and geophysical logs) from wells in the 

Black Warrior basin (Thomas, 1972a). More detailed descriptions, as 'W'ell as detailed stratigraphic 

cross sections and maps, have been published in 

Monograph 12 of the Geological Survey of Alabama 

(Thomas, 1972a). The regional setting of Mississippian rocks in Alabama has been discussed .in the 

context of stratigraphic cross sections and maps 

(Thomas, 1974). 

This paper sum:marizes published descriptive data 

available in 1977 and reviews the evolution of stratigraphic subdivision and correlation in Alabama. The 

data and conclusions are summarized in a discussion 

of depositional and tectonic framework. The manuscript has been review¢ by J. A. Drahovzal and G. 

H. Mack. 

The stratigraphic nomenclature used in this paper 

has not been reviewed by the Geologic Names Com~ 

mittee of the U.S. Geological Survey. The nomenclature used here conforms with the current usage of 

the Geological Survey of Alabama. 

MISSISSIPPIAN LITHOFACIES 

The Mississippian System o.f Alabama may be 

divided into two general units (fig. 2). The lower 

unit is a regionally extensive interval of cherty limestone and chert (Fort Payne and Tuscumbia formations) . The Fort Payne Chert is underlain by· a thin 

widespread green shale (Maury Shale) that marks 

the l>Me of the Mississippian System in Alabama. 

The upper part o.f the· Mississip·pian (above Tuscumbia) encompasses three different laterally equivalent facies. In north-central Alabama, the upper part 

of the Miss.iS&ippian is almost entirely limestone 

(Monteagle and Bangor Limestones). The carbonate 

facies grades southwestward into a succession of 

shale and sands·tone (Floyd and Parkwood formations) . Toward the northeast, the upper part of the 

carbonate facies grades into another succession of 

shale and sandstone (Pennington Formation) . All 

three facies of the upper part of the Mississippian 

are overlain by massive sandstone and quartz-pebble 

conglomerate of the Pennsylvanian Pottsville Formation. 

T.he Fort Payne-Tuscumbia interval is more than 

100 m thick in north-central Alabama on the East 

Warrior platform, but toward the southwest, the 

cherty carbonate interval thins gradually to less 

than 50 m in the Black Warrior basin (figs. 2, 3). 

Similarly, toward the southeast in Appalachian synclines, the Fort Payne-Tuscumbia interval thins to 

less than 50 m and pinches out locally. 

The thickness of Mississippian rocks between the 

top of the Tuscumbia and the base of the Pottsville 

ranges from a minimum of about 200m on the East 

Warrior platform in north-central Ala;bama to more 

than 1,000 min the Coosa synclinorium (figs. 2, 3). 

The thickness of the upper part of the Mississippian 

is less than 300 m across the East Warrior platform, 

which encompasses the eastern end of the Black 

Warrior basin and the northwestern part of the 

Appalachian fold and thrust belt, including the 

Sequatchie anticline. The southwestern edge of the 

E.ast Warrior platform is marked by an abrupt 

southwestward increase in thickness of the upper 

part of the Mississippian; in the Black Warrior 

basin, the thickness. increases 1A> more than 500 m. 

The East Warrior platform is bounded on the southeast by thicker sections in Appalachian synclines. 

Maximum thickness is more than 400 m in the 

Blount Mountain and Lookout synclines, more than 

800 m in the Cahaba syncline, and more than 1,000 

min the Coosa synclinorium. 

The Floyd-Parkwood clastic facies thickens southwestward in the Black Warrior basin and is also 

relatively thick in the Cahaba and Coosa synclines 

(fig. 2). The clastic facies grades northeastward 

into the carbonate facies along a boundary that 

trends southeastward across the Black Warrior 

basin, diagonally across the East Warrior platform, 

and into· the northwestern part of the Appalachian 

fold and thrust belt, where the facies boundary is 

approximately perpendicular to Appalachian structural strike. Tongues of cla.stic rocks extend northeastward fro~m the clastic facies and pinch out toward the northeast within the carbonate facies on 

the East Warrior platform. The most extensive 

tongue of the clas.tioc facies (Pride Mountain Formation and Hartselle Sandstone) extends from the 

lower part of the Floyd Shale and underlies the 

Bangor Limestone in north-central Alabama (fig. 2). 

Farther northeast, the Pride Mountain-Hartselle 

clastic tongue grades northeastward into the Monteagle Limestone and pinches out between the Monteagle and Bangor Limestones (figs. 2, 3) . The 

upper ·part of the clastic facies grades northeastward· into the Bangor Limestone across the south-
14 

H 

G 

F 

E 

THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

A 

BLACK WARRIOR BASIN 

SOUTHWEST 

B 

CAHABA SYNCLINE 

SOUrHWEST 

H 

G 

EXPlANATION 

Q Sandstone 

~ Shale, mudstone 

E:;j Limestone 

Chert nodules 

in limestone 

Chert and 

limestone 

~ Chert 

fl3 Dolostone 

10 

EAST WARRIOR PLATFORM 

BLOUNT MOUNTAIN 

SYNCLINE 

Datum: base Pottsville 

c 

300 METERS SOUTHWEST 

200 

100 

H 

20 30 KILOMETERS 

F 

A' 

NORTHEAST 

B' 

LOOKOUT SYNCLINE 

COOSA SYNCLINORIUM 

Datum: base Pottsville 

NORTHEAST 

E D Be 

A 

C' 

NORTHEAST 

F 

Eo 

~ A 

FIGURE 2.-Diagrammatic stratigraphic cross sections of Mississippian rocks in Alabama. End points of cross sections are shown on map in figure 1. Letters A through H on cross sections show approximate stratigraphic posi-

. tions of maps in figure 5. 
MISSISSIPPIAN STRATIGRAPHY OF ALABAMA 15 

\ 

\ 

I 

\ 

\ 

\ 

EXPLANATION \ 

-50-Isopach of Fo~ayne- \ 

Tuscumbia (METERS) .'"'-. 

• • • • • • • • • Southeast limit ,J' 

of Fort Payne : 

M / 

1111111111 Area of facl~ transttk>n ~ PM from Monteagle {M) '\ 

to Pride Mountain (PM) , 

P(p·o-o-c j ogo~o~c Area of massive oolitic 0 ..., "' " ' lim~tone and local \ 

Isopach maximum of •• 

,. --.. --------------~~~! .!:.~-~~~- ___ )_ 

~ l 

EXPLANATION 

W<. • • PG • Limit of sandstone In 

Parkwood (PI<) and Pennington ( PG) 

(letters where sandstone present) 

-1.0-Isopach of Interval between 

top of Tuscumbia and 

base of Pottsville (Kll.OMETER) 

\ 

I 

\ 

\ 

\ 

\ 

\ 

........ 

,J" 

l 

( 

\ 

i 

\. , .. - .. -----------------------.- __ j_ 

(_ ) 

l () ') j;L~ 25 50 75 100 KILOMETERS 

FIGURE a.-Generalized isopach and facies maps of parts of Mississippian System in Alabama. 

western part of the East Warrior platform. Similar 

pattern1s of distribution of the m~ajor facies prevail 

along Appalachian synclines; however, the clastic 

facies is thicker and extends much farther northeast along the more southeasterly structures. In the 

relatively thicker .sections· along Appalachian synclines, the upper part of the claJs.tic facies extends 

far to the northeast above the Bangor Limestone 

(fig. 2). In the Coosa synclinorium, the clastic facies 

extends to the northeast end of the outcrop, and the 

carbonate facies is represented only by a southwestthinning tongue of lim·estone and chert (fig. 2) . Distribution of the Floyd-Parkwood clastic facies indicates that the rocks in Alabama are at the eastern 

fringe of a regionally extensive clastic wedge that 

includes the very thick Mississippian clastic rocks 

of the Ouachita Mountains (Thomas, 1974, p. 201; 

1977, p. 1259). 

The Pennington Formation is restricted to the 

northeastern corner of Alabama and grades westward into the upper P,·art of the Bangor Limestone . 

(fig. 2). The Pennington Formation of Alabama 

evidently is only the distal fringe of a regionally 

extensive clastic wedge centered farther northeast 

(Thomas, 1974, p. 205; 1977, p. 1258). 

EVOLUTION OF STRATIGRAPHIC 

NOMENCLATURE 

In 1879, Smith established a threefold division of 

Carboniferous rocks in Alabama and identified 

regional equivalents (fig. 4). The Lower Sub-Carboniferous was divided into Lower Siliceous ( equivalent to Keokuk and Burlington) and Upper Siliceous (equivalent to St. Louis). The Upper Sub-:-

Carboniferous or Mounta;in Limesto,ne (equivalent 

to· Chester) contained the entire carbonate sequence 
16 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

SMITH SMITH SMITH SMITH McCALLEY 

1879 1890 1892 1894 1896 

s N s N s N 

COAL MEASURES COAL MEASURES COAL MEASURES COAL MEASURES COAL MEASURES 

BANGOR w BANGOR BANGOR 

LIMESTONE ..J 

<{ LIMESTONE LIMESTONE :I: 

w C/) w z 0 z 

~ z C/) OX MOOR <{ ~ OX MOOR w LA GRANGE SANDSTONE OX MOOR w w ~ SHALE z ~ HARTSELLE 

::::J SANDSTONE AND SANDSTONE ~ ::::J AND SANDSTONE 

z SHALES C/) z SANDSTONE 

~ 0 

z ~ z <{ z => C/) => 

0 a: 0 ~ 0 ~ HARTSELLE 

BANGOR 0 BANGOR SANDSTONE 

LIMESTONE ~ LIMESTONE X 

0 

UPPER SILICEOUS· ST. LOUIS OR TUSCUMBIA OR 

HUNTSVILLE TUSCUMBIA (ST. LOUIS) LIMESTONE ST. LOUIS 

FORT PAYNE CHERT LIMESTONE 

LOWER SILICEOUS LAUDERDALE LAUDERDALE (KEOKUK) LAUDERDALE OR 

(KEOKUK) CHERTY LIMESTONE KEOKUK CHERT 

BUTTS BUTTS WELCH. THOMAS 

1910 1926; 1927 1958 1972a 

s N s N sw NE 

POTTSVILLE FORMATION POTTSVILLE FORMATION POTTSVILLE FORMATION 

PARKWOOD I PARKWOOD I PARKWOOD- - FORMATION HIATUS FORMATION HIATUS - FORMATION- PENNINGTON - I PENNIN~T_ON PENNIN~l__ON - - FORMATION 

FORMATION I FORMATION - - - FLOYD I FLOYD -I - SHALE I BANGOR SHALE BANGOR - BANGOR LIMESTONE 

I LIMESTONE LIMESTONE --

- - I I - - HARTSELLE SANDSTONE MEMBER HARTSELLE SANDSTONE SANDSTONE 

HARTSELLE FLOYD 

SHALE 

..=:-

- SANDSTONE 

HARTSELLE -

-

-- GOLCONDA FORMATION l:i!.:f~-t;,~. tt!LL - I MYNOT SAND- I PRIDE MOUNTAIN -

CYPRESS SANDSTONE FORMATION - I STONE MEMBER I - ~ SA~~~kL - I <t ME 

~ I - z SOUTHWARD 

I GASPER FORMATION => ~ SPRING SS MBR - I - FLOYD BANGOR ~~ WAGNON - SHALE I LIMESTONE MEMBER I - MONTEAGLE 

BETHEL SANDSTONE ~ ~ TANY~~~:FNCH - LIMESTONE I -LL IER 

g: I ALSOBROOK - I 

STE. GENEVIEVE LIMESTONE MEMBER -

I ST. LOUIS TUSCUMBIA TUSCUMBIA 

LIMESTONE LIMESTONE TUSCUMBIA LIMESTONE 

WARSAW 

FORT PAYNE CHERT FORT PAYNE CHERT FORT PAYNE CHERT 

FIGURE 4.-Evolution of stratigraphic subdivision and .nnmenclature of Mississippian rocks in Alabama. 
MISSISSIPPIAN STRATIGRAPHY OF ALABAMA 17 

above the lower cherty unit. Smith ( 1879, p. 17) 

designated the local name, LaGrang·e Sandstone, for 

a persistent sandstone within the Mountain Limestone. The Coal Measures included the coal-bearing 

sequence later assigned to the Pennsylvanian 

System. 

Later, Smith ( 1890) applied local formation 

names to Mississippian stratigraphic units (fig. 4). 

The Fort Payne· Chert encompassed all the cherty 

limestones in the siliceous Lower Sub-Carboniferous. The carbonate sequence above the Fort 

Payne Chert was called the Bangor Limestone. 

Toward the south in Alabama, the Bangor Limestone is replaced by a sandstone and shale succession 

called Oxmoor Sandstone and Shales (Smith, 1890, 

p. 155) . The name Oxmoo·r was extended to replace 

Lagrange for the sandstone within the limestone 

sequence. The Oxmoor included the entire southwestern clastic sequence. . 

In summary reports, Smith (1892, 1894) defined 

two divisions of the beds originally called Fort 

Payne Chert (fig. 4). The upper cherty limestone 

unit was referred to as St. Louis or Huntsville in 

1892 and as the Tuscumbia (St. Louis) Limestone 

in 1894. The lower subdivision was called Lauderdale (Keokuk) in 1892 and Lauderdale (Keokuk) 

cherty limestone in 1894. Smith ( 1894) used the 

name Hartselle Sandstone to replace Lagrange and 

Oxmoor for the sandstone unit within the Bangor 

Limestone. 

McCalley (1896, p. 40) restricted Bangor to the 

I~imestone above the Hartselle Sandstone and extended the Hartselle Sandstone downward to· include 

a succession of sandstone and shale beds below the 

Bangor Limestone and above the Tuscumbia (fig. 4) . 

McCalley ( 1896, p. 40) recognized a prominent 

sandstone (Hartselle of earlier and later use) at the 

top of his Hartselle and described the westward or 

southwestward thickening of the sandstone-shale 

unit. 

Butts (1910, p. 7) recogniz~d equivalence of the 

carbonate sequence of northe,rn Alabama to part of 

the clastic sequence to the south and modifieq the 

stratigraphic nomenclature to reflect that interpretation (fig. 4). Fort Payne Chert was restricted. 

to the bedded ~chert previously called Lauderdale 

cherty lim.estone. Butts (1910, p. 7) extended Bangor Limestone downward to the top of the redefined 

Fort Payne and recognized a gradational contact between the Fort Payne and cherty limestone of the 

lower Bangor. Following Smith (1894), Hartselle 

Sandstone was defined as. a member of the Bangor. 

Butts (1910, p. 8) extended use of Floyd Shale from 

northwest Georgia as the shaly lower part of the 

clastic sequence and defined a new name, Parkwood 

Formation, for the sandstone-shale succession of 

the upper part. Floyd and Parkwood replaced Oxmoor (fig. 4). Tne name Pennington Formation was 

extended from Virginia for shale above the Bangor 

Limestone (fig. 4). Butts (1910, p. 7) described the 

Pennington as being overlain by the Pottsville Formation on the north and by the Parkwood Formation on the south. Butts (1910, p. 7) concluded that 

the Bangor and Pennington are contemporaneous 

with the Floyd and are older than the Parkwood. 

He (1910, p. 8) suggested that where Parkwood is 

present, sedim.entation was continuous from Mis,sissip·pian into Pennsylvanian. Absence of Parkwood 

below the Pottsville north of Birmingham was regarded as an indication of regional unconformity 

between Mississippian and Pennsylvanian rocks 

(Butts, 1910, p. 8). 

In the classic report on the geology of Alabama, 

Butts (1926) retained the use of local stratigraphic 

names for several units and extended names from 

the Mississippi Valley for other stratigraphic subdivisions in Alabama (fig. 4). Tuscumbia Lim·estone 

was used interchangeably with Warsaw and St. 

Louis for the cherty limestone above the Fort Payne 

Chert. Formation names extended from the Mississippi Valley were applied to the succession of shale, 

limestone, and sandstone between the Tuscumbia 

and the Hartselle (fig. 4). Bangor Limestone wa.s 

restricted to beds above the Hartselle Sandstone 

(Butts, 1926, p. 195), and Hartselle was raised to 

formation rank (Butts, 1926, p. 192). The Pennington Formation apparently was. described only for 

beds between Bangor and Pottsville in northern 

Alabama (Butts, 1926, p. 199) ; later, Butts (1927, 

p. 12) cons-idered the shale between Bangor and 

Parkwood south of Birmingham (Pennington of 

Butts, 1910, p. 7) as part of the Floyd Shale. 

Recognizing the impracticality of identification of 

the Mississippi Valley units for the beds between 

Tuscumbia and Hartselle in northwestern Alabama, 

Welch (1958) defined the entire succession of shale, 

limestone, and sandstone as the Pride Mountain 

Formation. Welch ( 1958) provided member definition for each part of the formation, which is described as consisting "of relatively thick units of 

shale that alternate with thinner units of limestone, 

sandstone, and siltstone" (fig. 4). The Pride Mountain Formation constitutes a clastic tongue in the 

lower part of the Mississippian carbonate sequence; 
18 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

it grades northeastward into the limestone sequence 

in northeastern Alabama. 

Stratigraphic subdivisions currently used for Mississippian rocks by the Geological Survey of Alabama (fig. 4) were outlined in a comprehensive review of Mississippian stratigraphy of Alabama 

(Thomas, 1972a). The southwestern clastic facies is 

divided into the Floyd Shale and the P~rkwood Fo·rmation. Generally, the Floyd Shale overlies. the Tuscumbia Limestone. The Tuscumbia evidently grades 

southeastward into shale, and where the Tuscumbia 

is absent, Floyd Shale rests directly on the Fort 

Payne Chert. A tongue of t.he lower part of the clastic sequence extends northeastward into the carbonate facies and is divided into the Pride Mountain Formation (shale, sandstone, and limestone) 

and the Hartselle Sandstone at the to.p. The Hartselle 

Sandstone pinches out both to the southwest within 

the shale unit in the lower part of the clastic facies 

and to the northeast within the carbonate facies. 

Southwest of the pinchout o.f the Hartselle Sandstone, the Pride Mountain Formation below is not 

distinct from the Floyd Shale above, and the Floyd 

Shale extends down to the top o.f the Tuscumbia 

Limestone. Toward the northeast, in northeastern 

Alabama, the Pride Mountain Formation grades into 

a limestone unit between the Tuscumbia and Hartselle. The name Monteagle Limestone was extended 

from southern Tennessee for the limestone above the 

Tuscumbia and below the Hartselle · Sandstone or 

Bangor Limestone (Thomas, 1972a, p. 19), and Monteagle replaced the names Butts (1926) had extended 

from the Mississippi Valley. The uppe1r part o.f the 

Mississippian carbonate sequence in Alabama is the 

Bangor Limestone. The Bangor overlies the Hartselle Sandstone, and toward the northeast where the 

Hartselle pinches out, the Bangor rests directly on 

Monteagle Limestone. East of the pinchout o.f the 

Hartselle Sandstone, the Monteagle and Bangor 

Limestones are not differentiated. In northeastern 

Alabama, the upper part of the Bangor grades 

northeastward into a clastic facies of shale, mudstone, sandstone, dolostone, and limestone. The name 

Pennington Formation has been restricted to the 

clastic facies on the northeast (Thomas, 1972a, p. 

83). 

LITHOSTRATIGRAPHY 

MAURY SHALE 

The Maury Shale is a thin persdstent unit of green 

clay shale characterized by phosphatic nodules. In 

northern Alabama, the Maury is generally less than 

2 m thick; however, the formation provides a distinctive lithologic marker at the base of the MissisSiippian System. 

FORT PAYNE CHERT 

The Fort Payne Chert in Alabama is typified by 

buff-weathered chert in irregular nodular beds. 

Commonly, the weathered chert contains abundant 

molds of echinoderm columnals and brachiopods, 

and the texture o.f some of the weathered chert suggests decalcified silic·eous limestone. In unweathered 

exposures and in the subsurface, the Fort Payne is 

dark-gray to light-gray Sliliceous micrite and bluegray to smoky chert in irregular beds and nodules. 

The formation locally includes light-gray coarse bioclastic limestone in lenses less than 3 m thick. The 

Fort Payne Chert includes some dark shale in northwestern Alabama (Butts, 1926, p. 164) and shaly 

beds in eastern Alabama. In northern Alabama, the 

formation oontadns geodes. 

The Fort Payne ranges in thickness from more 

than 50 m on the East Warrior platform to less than 

20 m on the southwest in the Black Warrior basin. 

The formation also thins southeastward across the 

Appalachian fold and thrust belt. Apparently the 

Fort Payne Chert pinches out southeastward along 

an irregular line along the Coosa deformed belt and 

the upplunge southwest end of the Coosa synclinorium (fig. 3). 

The oontact between the Fort Payne Chert and 

Tuscumbia Limestone is gradational from the siliceous micrite and bedded chert typical of the Fort 

Payne upward to a succession of light-colored bioclastic limestone and micrite containing abundant 

nodules of light-colored chert (Thomas, 1972a, p. 

12). Differentiation of the two· units is progressively 

less distinct westward .in the Black Warrior basin. 

Where the Tuscumbia Limestone is absent along the 

southeastern Appalachian structures, the Fort 

Payne is overlain by dark clay shale and argillaceous 

limestone o.f the Pride Mountain Formation-Floyd 

Shale. 

TUSCUMBIA LIMESTONE 

The Tuscumbia Limestone consists mainly of 

light-gray micrite and bioclastic limestone in thick 

beds. Crossbedded, coarse crinoidal limestone beds 

are locally as much as 3 m thick. Oolitic limestone is 

rare. In northeastern Alabama, thin lenses and beds 

of finely crystalline dolostone and dolomitic limestone are scattered randomly throug'lhout the Tus-
MISSISSIPPIAN STRATIGRAPHY OF ALABAMA I9 

cumbia; dolostone is more common in equivalent 

beds in southern Tennessee (Ferguson and Stearns, 

1967, p. 56). Light-gray and white chert nodules are 

common throughout the formation; dark-gray chert 

is less common. Part o.f the ·chert contains fossil 

molds. Fenestrate bryozoans are locally abundant. 

Concentrically banded, concretionary chert is abundant locally. 

The Tuscumbia Lim·estone is more than 50 m 

thick on the East Warrior platform in north-central 

Alabama; it thins gradually southwestward in the 

Black Warrior basin to less than 15 m (fig. 2) . 

Along Appalachian synclines, the formation thins 

and pinches out to the southeast and southwest, and 

it is absent at the southwest end of the Cahaba syncldne and along the Coosa synclinorium, except 

locally on the northwest limb (fig. 2). 

Where the Tuscumbia is overlain by the clastic 

facies, the basal beds of the Pride Mountain Formation-Floyd Shale commonly are shaly, oolitic, and 

(or) sandy limestone that suggests an upward 

gradation into the shale success·ion. The pinchout o.f 

the Tuscumbia along Appalachian synclines may be 

a resul~t o.f lateral gradation into the lower part o.f 

the clastic facies (Thomas, 1972a, p. 17). Alternatively, thinning of the Tuscum·bia in the Black Warl'lior basin has been attributed to an unconformity 

at the top of the formation (Welch, 1958; 1959). In 

northeastern Alabama, the contact between the Tuscumbia and overlying Monteagle Limestone· is gradational; the Monteagle is characterized by lightcolored massive oolitic Hmestone and contains significantly less chert, dolostone, and micrite than 

does the Tuscumbia. 

MONTEAGLE LIMESTONE 

The Monteagle Limestone is characterized by 

light-gray ooli.tic limestone in crossbedded, massive 

beds more than 3 m thick. Thick-bedded bioclastic 

limestones are common. Interbeds o.f mdcrite are less 

common. Interbeds of finely crystalline dolostone 

and dolomitic limestone are rare and are randomly 

distributed. Nodules of gray and black chert are 

rare. The Lost River Obert, a marker in the lower 

Monteagle of Tennessee (Ferguson and Stearns, 

1967, p. 57) , does not appear to· be laterally persistent in Alabama. In the northeastern corner of 

Alabama, the middle part of the Monteagle contains 

a distinctive unit of interbedded limestone and shale 

about 8 m thick (Thomas, 1972a, p. 21). 

In northeastern Ala;bama, the Monteagle is approximately 65 m thick and is almost entirely limestone. Toward the southwest on the East Warrior 

platform, the Monteagle grades southwestward to 

clay shale of the Pride Mountain Formation (figs. 

2, 3) . The facies boundary between the Monteagle 

and Pride Mountain rises stratigraphically north-

. eastward, and a thin tongue of clay shale of the 

upper Pride Mountain extends northeastward above 

the Monteagle and below the eastward-pinching 

Hartselle Sandstone. East of the pinchout of both 

Pride Mountain and Hartselle, the Monteagle is 

overlain by the Bangor Limestone in a continuous 

succes&ion of limestone beds. Although a MonteagleBangor contact may be projected eastward, the two 

formations are clearly s·eparable only where the 

Hartselle and (or) Pride Mountain intervene, and 

the undifferentiated Monteagle-Bangor cannot be 

reliably subdivided farther east (Thomas, 1972a, p. 

22). 

The Monteagle Limestone extends southeastward 

into Lookout syncline and grades southwestward to 

the Pride Mountain Forma;tion near the southwest 

end of the syncline, just as it does on the East Warrior platform (figs. 2, 3). Southeast o.f the Lookout 

syncline, the Monteagle grades into the clastic facies 

(Pride Mountain-Floyd). 

BANGOR LIMESTONE 

The Bangor Limestone is mainly bioclastic limestone and oolitic limestone. The formation also includes micrite and thin beds o.f shaly argillaceous 

limestone and calcareous shale. Thin laterally discontinuous beds o.f maroon and green blocky mudstone are scattered through the upper half of the 

formation. Chert is generally restricted to the upper 

part of the Bangor. A few small mass·es of coral are 

scattered widely. In northeastern Alabama, a dolostone unit extends from the basal Pennington Formation into· the Bangor Umestone. 

The Bangor Limestone ranges approximately 

from 130 to 180 m in thickness on the East Warrior 

platform. A linear isopach and limestone isolith 

maximum is alined approximately with the southwestern edge of the East Warrior platform in northwestern Alabama and trends southeastward diagonally .across the pla-tform northeast of the edge 

(Thomas, 1972a, pl. 11; 1974, fig. 6). Southwest of 

the linear isopach-isolith maximum, thickness of 

limestone decreases where the Bangor grades southwestward into the clastic facies (Thomas, 1972a, 

p. 50). Similarly, the Bangor thins northeastward 

where the upper part grades laterally into the Pennington Formation (fig. 2). 
I10 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

The Bangor thickens southeastward to more than 

180 m along the Sequatchie anticline and Blount 

Mountain and Lookout synclines .. Farther southeast 

in the Appalachian fold and thrust belt, the Bangor 

generally is less than 150 m thick, but there, much 

of the Bangor-equivalent interval is in the FloydParkwood clastic facies (fig. 2). However, the Bangor Limestone also thins southwestward and grades 

to clastic rocks along strike· of the Cahaba syncline. 

A similar pattern prevails along the Coosa synclinorium (fig. 2), where the southwest-thinning Bangor Limestone Tongue of the Floyd Shale is mostly 

weathered chert on the northwest limb and mostly 

limesrtone along the Coosa deformed belt. 

Oolitic limestone is most abundant along the 

linear isopaoh maximum across the southwestern 

part of the East Warrior platform (fig. 3); along 

the same area, the formation oontains three separate 

massive oolitic limestone units, each as much as 

12 m thick (Jones, 1928, p. 13; Thomas, 1972a, p. 

49). Farther northeast on the East Warrior platform, oolitic limestone units appear thinner and less 

extensive, and both oolitic and bioclastic limestones 

are generally in thick beds or large lenses, which are 

cross bedded. 

On the East Warrior platform, the Bangor is 

overlain by the Pottsville Formation. The contact is 

within a succession that includes (in ascending 

order) limestone, maroon and g.reen mudstone, carbonaceous shale and thin-bedded sandstone, and the 

characteristic thiock massive sandstone of the lower 

Pottsville. Thickness of fine clastic rocks between the 

top of the limestone succession and the mass.ive 

sandstone is generally less than 20 m but varies 

locally. Various components of the gradational succession are not everywhere present, and locally the 

massive sandstone appears. to rest directly on the 

limestone. The succession indicates that the BangorPottsville contact is gradational, but channels are 

suggested where the masS'ive sandstone rests on 

lim·estone. However, the possible channels appear to 

be local, and the ·contact app·arently is not a regional 

unconformity (Thomas 1972a, p. 94). 

FLOYD SHALE 

The Floyd S.hale is a dark -gray clay shale that 

constitutes the lower part of t~he southwestern Mississippian clastic sequence. In the Black Warrior 

basin, the Floyd grades upward into the Parkwood 

Formation, and the upper part of the Floyd grades 

northeastward into the Bangor Limestone (fig. 2). 

The Floyd and Parkwood grade northeastward into 

the Bangor along an irregular southeast-trending 

line near the southwestern edge of the East Warrior 

platform; however, an extensive tongue of the lower 

part of the Floyd Shale extends far northeast beneath the Hartselle Sandstone as the Pride Mountain Formation. Sandstone units characteristic o.f 

the Pride Mountain extend southwest into the lower 

Floyd. Along Appalachian synclines, where the Mississippian System is thicker than it is in the Black 

Warrior bas.in, the Floyd-Parkwood contact rises 

northeastward above the most extensive Bangor 

Limestone, and the Floyd Shale intervenes between 

the Parkwood and the Bangor (fig. 2). The clastic 

facies extends much farther northeast along Appalachian synclines than it does on the East Warrior 

platform. In the Coosa synclinorium, the Floyd includes a southwest-thinning tongue of Bangor Limestone, as well as the northeast, southeast, and southwest limits of the Hartselle Sandstone (fig. 2). The 

Floyd Shale extends northeast to the end of exposures in the Coosa synclinorium. 

The Floyd Shale is predominantly dark-gray clay 

shale. Siderite nodules are s.cattered through the sequence. Parts of the shale sequence are calcareous 

and include shaly, argillaceous limestone beds. Within the Floyd in the Black Warrior basin, a limestone 

tongue o.f the lower Bangor contains dark-gray 

chert. 

Around the southwest end of the Coosa synclinorium, the lower Floyd Shale includes beds less than 

3 m thick of dark-gray argillaceous limestone that 

contains abundant fenestrate bryozoans, echinoderm columnals, and brachiopods. Farther southwest, south of the Black Warrior basin on the 

Pickens-Sumter anticline, the lower part of the 

Floyd contains limestone units that attain an aggregate thickness of about 60 m. At the northeast end 

of the Coosa deformed belt and southeast of Lookout syncline, the Floyd contains relatively thick 

lim·es·tone units; however, complex structure obscures the stratigraphic position of the limestones. 

To the east in Georgia, the lower part of the Floyd 

Shale contains a limestone tongue equivalent to the 

Tuscumbia and (or) Monteagle, and the Floyd is 

overlain by a tongue of the Bangor Limestone. The 

Ji.mestones in the Floyd of eastern Alabama may be 

equivalent to either or both limestone tongues within 

the clastic sequence in Georgia. 

PRIDE MOUNTAIN FORMATION AND 

HARTSELLE SANDSTONE 

The Pride Mountain Formation and Hartselle 

Sandstone constitute a laterally extens-ive tongue of 
MISSISSIPPIAN STRATIGRAPHY OF ALABAMA Ill 

shale and sandstone that extends from the lower part 

the Floyd Shale and pinches. out northeastward into 

the carbonate facies between the Monteagle and Bangor Limestones (figs. 2, 3). Thickness of the tongue 

is generally less than 110m. The clastic tongue contains four separate sandstone units, o.f which the 

lower three are in the Pride Mountain Formation 

and the upper is the Hartselle Sandstone. Each of 

the four sandstone units. is broadly linear in distribution and trends southeast, parallel with the major 

facies boundaries across the southwestern part of 

the East Warrior platform. Each of the linear sandstones pinc.hes out southeastward along trend. The 

Pride Mountain .sandstone units are thin or absent 

in the Appalac.hian fold and thrust belt southeast 

of the Birmingham anticlinorium. The Hartselle 

Sandstone extends as far southeast as the northwest 

limb of the Coosa synclinorium. 

The southwest and southeast limits of the four 

sandstones are within the gray shale of the lower 

part of the dastic facies. By de,finition, the Pride 

Mountain includes the shale and sandstone succession below the Hartselle Sandstone ; beyond the 

limit of Hartselle Sandstone, beds equivalent to the 

Pride Mountain are included in the lower part of the 

Floyd Shale (fig. 2). Sandstone units of the Pride 

Mountain extend farther southwest than the Hartselle and are, therefore, included in the Floyd Shale. 

The area of the lower sandstone unit is relatively 

wide and extends from the East Warrior platform 

southwestward into the Black Warrior basin. The 

middle and upper units are confined to narrow area8 

on the platform; however, northwest along trend, 

both extend across the platform edge into the Black 

Warrior basin. Farther west in the Black Warrior 

basin in Mississippi, the sandstones .have a more 

blanketlike distribution (Thomas, 1972b, p. 98; 

1974, p. 196). The three sandstone units. in the 

Pride Mountain pinch out northeastward into a shale 

succession that, farther northeast, grades into the 

Monteagle Limestone beneath the Hartselle Sandstone. 

The Pride Mountain (lower Floyd) sandstones 

are characteristically quartzose; however, the sand-

.stone units commonly contain beds of partly sandy 

bioclastic limestone. ·Locally the sandstone grades 

laterally to limestone. The lower beds of the Pride 

Mountain (lower Floyd) are generally shaly and 

(or) oolitic Hmestone, and locally the lower sandstone unit is interbedded with the basal limestone. 

The sandstone units grade laterally to thin-bedded 

or shaly argillaceous sandstone and shale. The units 

locally consist of very fine grained sandstone in 

ripple-laminated beds and lenses less than 5 em 

thick._ Clay laminae and beds of shale alternate with 

the thin sandstone beds. In some places, the laminae 

are disrupted by abundant burrows, and the bed 

surfaces are marked by numerous trails. Locally, 

channel-filling conglomerate at the base of a sandstone unit contains clasts of limestone, claystone, 

and sandstone as much as 10 em in diameter and 

fragments of corals, bryozoans, and brachiopods 

(Thomas, 1972a, fig. 13). Near the northeast limit 

of each sandstone, lithology and thickness vary 

locally. 

Apart from the sandstone units, the Pride Mountain Formation consists of gray clay shale and includes .calcareous shale and shaly argillaceous limestone. The calcareous rocks generally contain abundant fossils of bryozoans and brachiopods. Parts of 

the shale succession contain abundant siderite 

nodules. Plant fragments are scattered in some of 

the shale beds (Butts, 1927, p. 12). 

The Hartselle Sandstone is the thickest and most 

extensive of the s·a}\dstone units on the East Warrior 

platform. Maximum thickness o.f the formation is 

more than 45 m along a narrow southeast-trending 

area across the southwestern part of the East Warrior platform. The linear area of maximum thickness is parallel with and only 18 km northeast of the 

southwest limit of the sandstone. Northeast of the 

well-defined linear thick sandstone, the formation 

thins irregularly eastward. Limited data suggest 

other discontinuous southeast-trending isolith maxima separated by broad areas of thinner sandstone 

(Beavers and Boone, 1976, p. 11). Farther east, 

the sandstone thins -gradually and pinches out eastward between the Monteagle and Bangor Limestones. Near the east limit of sandstone, the Hartselle includes lenses of alternating thin laminae of 

quartzose sandstone and oolitic bioclastic limestone. 

Where the Hartselle overlies the thin east-pinching 

tongue of Pride Mountain shale, sandstone fills 

channels nearly 1 m deep, and where the Hartselle 

overlies the Monteagle Limestone, the upper limestone beds are sandy. Thickness o.f sandstone varies 

abruptly near the east limit; possibly, some sandstone lenses are isolated farther east within the carbonate facies. Eastward beyond the limit of sandstone, the Hartselle :horizon within the limestone 

succession may be marked by a thin bed of shale and 

(or) locally by crossbedded lenses and channeled 

limestone beds. In north-central Alabama, the Hartselle Sandstone grades upward to the Bangor Lime- ,_ 
112 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

stone through a few meters of calcareous clay shale 

and argillaceous limestone. 

The Hartselle Sandstone is generally a · lightcolored fine-grained quartzose sandstone. In northwestern Alabama, the formation includes two major 

facies: thick-bedded crosslaminated matrix-free 

sandstone and thin-bedded ripple-la·minated sandstone that has a terrigenous matrix and muds.tone 

interbeds (Beavers and Boone, 1976, p. 11). The 

Hartselle is characterized generally by thick-bedded 

crossbedded sandstone. S.ome beds are ripple 

marked, and thin-bedded ripple-laminated sandstone 

locally is marked by trails. Flat clay pebbles less 

than 3 em in diameter are scattered in the sandstone beds at some localities. Beds of shale and 

shaly sandstone make up a small proportion of the 

formation. Whole and fragmented fossils of brachiopods, bryozoans, and blastoids are common locally. 

Plant foss:ils, .including tree segments as much as 

60 em long and 15 em across, are imprinted on sandstone and shale beds. Large tree fragments, including a stump, were collected from the Hartselle of 

northwestern Al~bama (McCalley, 1896, p. 171-

176). 

Near the southwest end of the Lookout syncline 

and in the area farther north, the Pride Mountain 

Formation grades northeastward to the Monteagle 

Limestone, and the Hartselle pinches out northeastward within the carbonate facies. Along the Coosa 

synclinorium, where the clastic facies extends farther northeast, the Hartselle Sandstone pinches out 

northeastward within the shale succession in the 

lower part of the clastic facies. 

PARKWOOD FORMATION 

The Parkwood Formation is a succession of alternating units of shale and sandstone and is divisible 

into four cyclic intervals. Part of each cycle is 

dominated by sandstone; however, shale interbeds 

are ·common. Generally, the sandstone grades up into 

a dominantly shale unit, which grades up into a 

ihigher sandstone. Where the formation is thick, 

each cycle commonly includes more than 100 m of 

beds. Some sandstone units are locally more than 30 

m thick, and sandstone generally constitutes 15-40 

percent of the formation. The base of the formation 

is defined as the base of the lowest sandstone unit, 

and because the lower sandstone units successively 

pinch out northeastward, the base of the formation 

ascends stratigraphically in that direction. Aggregate thickness of sandstone and total thickness of 

the formation generally increase southwestward. 

The Parkwood Formation pinches out northeastward along an irregular, southeast-trending line 

that extends across the East Warrior platform and 

into the Appalachian fold and thrust belt (figs. 2, 

3). Along the Appalachian synclines, where the 

clastic facies is thickest, the Parkwood extends 

much farther northeast than on the East Warrier 

platform (figs. 2, 3). On the southeast limb of the 

Sand Mountain syncline and in Lookout syncline, 

Parkwood strata blend northeastward with clastic 

rocks of the southwest-thinning Pennington Formation, and the northeastern limit of Parkwood clastic 

sedim·ents is obscure. The Parkwood extends northeast to the up-plunge end of the Coosa synclinorium 

and the northeast end of the Coosa deformed belt. 

The sandstones are characteristically very fine to 

fine grained, argillaceous, and micaceous, but some 

are more quartzose. Flattened clay pebbles less than 

3 em in diameter are locally abundant. Beds range 

from thin and shaly to thick bedded and from planar 

to lens shaped. Ripple marks are relatively common, 

and some of the sandstones are crossbedded. Some 

beds and lenses are characterized by flaser bedding. 

Burrows and trails mark some beds. Thin clay partings and clay shale beds are common. 

Between the sandstone units are intervals of gray 

clay shale, silty clay shale, and mudstone. Nodules 

and thin nodular beds of siderite are common 

throughout but apparently are most abundant in the 

lower part of the formation. Silty laminae within 

the shales are locally interrupted by abundant 

burrows. 

Contacts of sandstone units with underlying and 

overlying clay shales are commonly gradational. 

Locally, sandstone units rest on s·ooured basal contacts, and sandstone fills shallow channels in the 

underlying shale. Lenses of clay-pebble and limonite-concretion conglomerate mark the bases of 

some sandstones, but other channel-filling sandstones are not conglomeratic. 

Extensive tongues o.f limestone extend from the 

Bangor Limestone southwest into the shale-dominated parts o.f the Parkwood. Argillaceous, bioclastic, and cherty limestones and rare oolitic limestone compose the tongues. Calcareous mudstone and 

maroon and green mudstone beds are associated 

wi.th the limestone beds. 

Marine fossils are abundant locally. The limestone 

beds contain abundant brachiopods, bryozoans, and 

echinoderms. Shale units locally contain abundant 

molds of braohiopods, pelecypods, and bryozoans. 

Poorly preserved molds o.f brachiopods and bryo-
MISSISSIPPIAN STRATIGRAPHY OF ALABAMA I13 

zoans are included in some of the sandstone beds, 

and molds of echinoderm columnals are widely 

scattered. 

Carbonaceous shale and sandstone containing 

small plant fragments are common in the upper 

part of the formation. Large plant fossils are preserved locally in sandstone. Carbonaceous shale near 

the top o.f the formation contains thin beds of clayey 

coal. The ·coal beds and the greatest concentration of 

carbonaceous sandstone and shale are in the upper 

75 m of the Parkwood in the Cahaba syncline. 

Across the Black Warrior basin and southwest 

edge o.f the East Warrior platform, the Parkwood 

grades northeastward laterally into· the Bangor 

Limestone. Along the .Appalachian synclines, the 

lower Parkwood grades northeastward into the 

Floyd Shale, which constitutes a transitional facies 

between the Parkwood and the Bangor. The Parkwood is overlain by a thick massive unit of quartzose 

sandstone, quartz-pebble conglomerate, and carbonaceous sandstone, which marks the base of the 

Pottsville Formation. In some places, the basal 

Pottsville sandstone fills erosional channels cut several meters into the underlying Parkwood beds, but 

at other localities, the contact is planar and appears 

conformable. 

PENNINGTON FORMATION 

The Pennington Formation is a succession of 

shale, mudstone, sandstone, dolostone, and limestone 

that overlies part of the Bangor Limestone in northeastern Alabama (figs. 2, 3). In the ·area northwest 

o.f the Wills Valley anticline, the clastic succession 

grades westward to limestone of the upper Bangor, 

but farther south along Appalachian structures, the 

Pennington merges southwes.tward with the northeast-wedging Parkwood clastic sequence. Along and 

northwest of the Sequatchie anticline, the base of 

the Pennington is marked by dull-gray, micrograined dolostone interbedded with maroon, green, 

and gray mudstone. The distinctive dolostone interval is virtually coextensive with the succeeding 

clastic rocks, but the dolos.tone extends. farther west 

into the limestone sequence. Southeast of the Sequatchie anticline, the dolostone is not commonly 

exposed and the lower part o.f the Pennington is 

gray shale and maroon and green mudstone. 

The Pennington Form·ation is predominantly gray 

clay shale. Maroon and green mudstones generally 

make up less than 10 percent o.f the total thickness. 

The formation contains beds o.f bioclastic, oolitic, 

and micritic limestones, typical of the Bangor 

Limestone, and the proportion o.f limestone increases 

westward. Toward the east, beds of very fine to finegrained generally argillaceous sandstone are common in the upper part of the Pennington. The sandstone beds generally are complexly overlapped lenses 

or . crossbeds ; and, in part, the sandstone grades 

laterally to mudstone. The sandstone is generally 

carbonaceous, and plant fragments are common. The 

sandstone-bearing succession commonly includes 

carbonaceous shale and thin shaly coal beds, which 

are generally less than 3,0 em thick. In eastern Alabama, one coal bed apparently grades laterally within a few tens of meters to a nodular bed o.f siderite 

that contains brachiopods and gastropods. Thickness 

of coal beds is greater to the northeast in Georgia 

and Tennessee, and some beds in the same stratigraphic position have been mined. The interval of 

sandy carbonaceous beds thickens eastward in Alabama to more than 30 m, and farther northeast, 

the equivalent succession is separated from the 

Pennington as the Raccoon Mountain Formation in 

Tennessee. 

The Pennington Formation overlies the lower part 

of the Bangor Limestone and grades laterally westward into the upper Bangor. 'The Pennington is 

overlain by massive sandstone of the lower Pottsville Formation. The coal-bearing upper Pennington 

(or Raccoon Mountain) appears to be gradational 

upward to the Pottsville. Prob3Jbly no major unconformity separates the Pennington and the Pottsville, 

although channel filling marks the base o.f the Pottsville sandstone in a few places. 

BIOSTRATIGRAPHY 

The Maury Shale contains abundant conodonts. 

The formation evidently encompasses three assemblage zones (Siphonodella isosticha-S. cooperi zone, 

Gnathodus semiglabe'r-Pseudopolygnathus multistriata zone, and Bactrognathus-Polygnathus communis zone) of the late Kinderhookian and early 

Valmeyeran (Drahovzal, 1967, p. 12). 

The Fort Payne Chert of northern Alabama contains the characteristic Keokuk forms, Spirifer 

logani and Brachythyris suborbicularis, and thus is 

correlative with at least the Keokuk of the Mississippi Valley (Drahovzal, 1967, p. 14). Fossils representative o.f Kinderhook, Fern Glen, Burlington, and 

Keokuk have been ·Collected from the Fort Payne 

Chert at several places in Alabama (Butts, 1926, p. 

166-167). Butts (1926) evidently included the 

Maury Shale with the Fort Payne, and, exclusive 

of the basal shale and associated limestone beds, the 
I14 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Fort Payne is equivalent to Keokuk (Drahovzal, 

1967, p. 14). 

The Tuscumbia Limestone in Alabama is equivalent to the Warsaw, Salem, and St. Louis of the Mississippi Valley (Drahovzal, 1967, p. 14). The lower 

Tuscumbia in northern Alabama contains a Warsaw-Salem fauna, including M arginirugus magnus, 

Reticularia setigera, and Spirifer bifurcatus; the 

upper part of the Tuscumbia contains a St. Louis 

fauna, characterized by Lithostrotionella castelnaui 

and Lithostrotion proliferum (Drahovzal, 1967, p. 

14). In northwestern Alabama, the St. Louis coral 

fauna is found only in small areas, and Butts ( 1926, 

p. 175) concluded that the St. Louis is absent except 

locally. 

The Pride Mountain Formation includes the units 

for which Butts ( 1926), on the basis of fossil 

faunas, extended the identification of the Ste. Genevieve, Bethel, Gasper, Cypress, and Golconda formations from the Mississippi Valley to Alabama 

(T·homas, 1972a, p. 26). The lower limestone unit 

of the Pride Mountain is recognized as equivalent to 

Ste. Genevieve because it locally contains abundant 

lnfiatia infiata (Productus infiatus) (Drahovzal, 

1967, p. 16). Butts (1926, p. 187-189) identified the 

Gasp~r by the presence of Campophyllum gasperense, 

Chonetes chesterensis, Talarocrinus, and other forms. 

Butts (1926, p. 184) correlated the underlying sandstone (now the lower sandstone unit of the Pride 

Mountain) with the Bethel Sandstone because it is 

overlain by limestone containing fossils "of lower 

Gasper age." However, the characteristics of Talarocrinus above :the sandstone in Alabama are more like 

those of the Renault than those of the Paint Creek 

in the Mississippi Valley, and the sandstone may be 

as old as Aux Vases (Drahovzal, 1967, p. 16). Butts 

(1926, p. 192) identified the Golconda on the basis 

of Camarophoria explanata, and he (p. 189) correlated the underlying sandstone (now the upper 

sandstone unit of the Pride Mountain) with the 

Cypress Sandstone on the basis of stratigraphic 

position. A goni.atite fauna from the lower part of 

the Pride Mountain Formation in northwestern Alabama includes Goniatites granosus, N eoglyphioceras 

subcirculare, Girtyoceras limatum, and Lyrogoniatites sp. cf. L. utahensis ( Drahovzal, 1972, p. 34-

35) ; comparison with sparse· goniatites from the 

Illinois section and with conodont ranges suggests 

a Homhergian age (J. A. Drohovzal, oral com.mun., 

1978). 

The lower part of the Monteagle Limestone· of 

northeastern Alabama contains a Ste. Genevieve 

fauna, characterized by Platycrinites penicillus 

(Platycrinus huntsvillae) (Butts, 1926, p. 182; 

Drahovzal, 1967, p. 16). The upper part of the 

Monteagle contains a Gasperian fauna, including 

Chonetes chesterensis (Drahovzal, 1967, p. 18). 

Golconda equivalents have not been found in the 

Monteagle in Alabama (Drahovzal, 1967, p. 19); 

however, Butts (1926, p. 191) reported Pterotocrinus capitalis from the section farther northeast 

in Tennessee. 

The· Hartselle Sandstone has been correlated with 

the Hardinsburg Sandstone of Illinois on the. basis 

of stratigraphic position between beds containing 

Golconda and Glen Dean faunas (Butts, 1926, p. 

195). 

The lower part of the Bangor Limestone contains 

a Glen Dean fauna, including Prismopora serrulata, 

Pentremites pyramidatus, and Pentremites brevis 

(Butts, 1926, p. 199). More recent work has confirmed the correlation of lower Bangor with Glen 

Dean on the basis of Pterotocrinus depressus and 

Pentremites robu.stus-maccalliei (Drahovzal, 1967, 

p. 20) as well as nonfenestrate bryozoans (McKinney, 1972). The age of the upper part of the Bangor 

is less well established. Pterotocrinus tridecbrachiatus from near the top of the Bangor in northcentral Alabama indicates correlation with the Kinkaid Limestone of Illinois (Drahovzal, 1967, p. 21). 

Drahovzal (1967, p. 21) reported a blastoid fauna, 

tentatively identified as Pentremites laminatus, that 

by correlation with conodont zones in Arkansas suggests correlation of the highest Mississippian beds in 

Alabama with the Grove Church Formation of the 

Mississippi Valley. 

The Floyd Shale contains fossils at few places. 

Butts (1926, p. 204) reported brachiopod-bryozoan 

faunas that indicate an age range of at least Gasper 

to Glen Dean. Rock-stratigraphic correlations show 

that the Floyd grades laterally into units of the carbonate facies between the Tuscumbia and the lower 

part of the Bangor. 

Fossils have been collected from several outcrops 

of the Parkwood Formation in the Appalachian fold 

and thrust belt. Butts ( 1926, p. 206) reported a collection from the Parkwood Formation that was "a 

mixture of Pennsylvanian and Mississippian fossils" 

and listed Derbya kaskaskiensis and Huste.dia mormoni, Pennsylvanian forms, and Spirifer leidyi and 

Reticularia setigera, Mississippian forms. The lower 

part of the Parkwood contains Mississippian fossils 

such as Archimedes and Fenestella tenax (Butts, 

1926, p. 206). A collection from a sandstone in the 
MISSISSIPPIAN STRATIGRAPHY OF ALABAMA 115 

upper part of the Parkwood is probably of Pennsylvanian age, but G. H. Girty (in a communication 

quoted by Butts, 1927, p. 13) expressed caution 

about the age assignment. The collection includes 

such forms as Spi1·i[er 1·ockymontanus, Composita 

subtilita, and Deltopecten occidentalis (Butts, 1926, 

p. 206; 1927, p. 13). Fossil plants of Pocahontas 

age have been reported from the upper part of the 

Parkwood (Moore and others, 1944, p. 686). On the 

basis of these data from outcrops along Appalachian 

structures, the lower part of the Parkwood has been 

considered Mississippian and the upper part, Pennsylvanian (Butts, 1927, p. 13; Culbertson, 1963a, 

p. E49; Wanless, 1975, p. 23). 

The Parkwood clastic facies grades laterally into 

the Bangor Limestone, and the two facies intertongue across a wide area. The rock-stratigraphic 

relationship suggests that the Parkwood and Bangor 

are temporally equivalent. However, the Bangor contains a well-documented Mississippian fauna, and 

time equivalence of Bangor and Parkwood is incompatible with the reported Pennsylvanian fossils 

of the upper Parkwood along Appalachian synclines. 

PoSISibly, differences in faunas of the Parkwood and 

Bangor reflect paleoecologic controls rather than 

time-stratigraphic controls. 

On the basis of rock-stratigraphic relationship, 

the Pennington Formation is considered to be equivalent to the upper part of the Bangor Limestone 

(Thomas, 1972a, p. 89). 

In a detailed investigation of crinoids in Mississippian rocks in Alabama, Burdick (1971) recognized three successive crinoid zones, in ascending 

order, the Platyc1-inites penicillus zone, Talarocrinus 

zone, and Agassizocrinus cf. A. conicus zone. The 

Platycrinites penicillt(,S zone is distinctive of Ste. · 

Genevieve; Tala1·oc1·inus, of lower Chesterian; and 

Agassizocrinus cf. A. conicus, of middle and upper 

Chesterian. T~he crinoid zones have been defined for 

the Mississippi Valley region, and Burdick (1971) 

found that in the Alabama section, the three zones 

are mutually exclusive. In Alabama, the Platycrinites penicillus zone is in the lower part of the Monteagle Limestone in northeastern Alabama and in 

the Pride Mountain Formation of northwestern 

Alabama (Burdick, 1971, p. 19). The Talarocrinus 

zone is recognized in the upper part of the Monteagle and in the Pride Mountain (Burdick, 1971, 

p. 20). The Agassizocrinus cf. A. conicus zone in 

Alabama is found as low as the hase of the Hartselle 

Sandstone and extends through the stratigraphically 

higher beds of the Hartselle, Bangor, and Pennington formations (Burdick, 1971, p. 21-22). 

BASE OF POTTSVILLE AND PROBLEM OF 

MISSISSIPPIAN -PENNSYLVANIAN BOUNDARY 

The lower part of the Pottsville Formation in 

northern Alabama is a massive quartzose sandstone 

and quartz-pebble conglomerate. Conglomeratic beds 

locally include carbonized plant fragments and siderite pebbles. The sandstone unit is as much as 200m 

thick but that includes a persistent middle shale 

interval (Culbertson, 1963a, fig. 193.1). 

Traditionally, the base of the Pottsville in Alabama has been regarded as part of a regional unconformity beneath the massive sandstone. The upward 

succession from prodelta shales of the Floyd, to distributary-front and marine-bay sandstones and 

shales of the Parkwood, and to delta-plain and barrier sandstones of the Pottsville suggests continuous 

sedimentation rather than a major unconformity. 

Channel fillings at the bas~e of the massive sandstone 

may reflect local channels within the delta plain. 

The Pennington-Pottsville contact may be interpreted similarly. Where the Pottsville overlies the 

Bangor Limestone, the gradational interval is relatively thin, but the succession commonly includes 

components of an upward transition from shallowmarine limestone to deltaic and coastal clastic sediments. The geographic extent of the Bangor Limestone is limited by Mississippian clastic facies that 

prograded onto the carbonate shelf from t.he southwest (Parkwood) and northeast (Pennington). Continuation of those processes evidently resulted in 

more widespread progradation o.f the overlying 

Pottsville sediments to completely cover the area of 

Bangor Limestone depos,ition in north-central Alabama. Thus, the contact o.f the Pottsville with the 

underlying Mississippian System can be regarded 

as part of a depositional continuum rather than as 

part o.f a regional unconformity. 

The base of the massive sandstone at the base of 

the Pottsville commonly has been considered to mark 

the approximate position of the Mississippian-Penn, 

sylvanian boundary. In part, that age assignment is 

based on the assumption of a regional unconformity 

coincident with a systemic boundary. In Alabama, 

Mississippian rocks are clearly documented by biostratigraphic data. Beds above the base of the massive sandstone of the lower Pottsville contain plant 

fossils, palynomorphs, and some invertebrate fossils 

that are of Pennsylvanian age (B~tts, 1926, p. 213; 

Upshaw, 1967). However, available biostratigraphic 
116 THE l\IISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

\ 

\ 

' 

A 

\ 

\ 

\ 

\ 

\ 

\ 

' 

\ 

8 \ 

\ 

\ 

' 

\ 

o\ 

\ 

\ 

\ 

\ 

FIGURE 5.-Generalized lithofacies and paleogeographic maps of Mississippian rocks in Alabama. Approximate stratigraphic position of each map is shown by letter on cross sections in figure 2. 

data do not precisely define the Mississippian-Pennsylvanian boundary. 

Available data indicate that the stratigraphically 

highest part of the Bangor is of M.ississi.ppian age. 

In northeastern Alabama, the Pennington Formation grades into the upper part of the Bangor and 

thus appears to be equivalent to the Bangor. Farther northeast, the upper pa·rt of the Pennington 

apparently is continuous with the Raccoon Mountain 

Formation in Tennessee, and the Raccoon Mountain 

Formation commonly is ·considered to be Pennsylvanian (Culbertson, 1963b; Milici, 1974, p. 118). 

These correlations do not conform to a single timestratigraphic surface at the systemic boundary. 

Spores frO'm a coal bed in the Raccoon Mountain 

Formation of Alabama have "definite Chesterian 

affinities" (Wilson, 1965, p. 49), and invertebrate 

fossils from equivalents of the Raccoon Mountain 

Formation in the northeast corner of Alabama are 

Mississippian ( M.ilici, 197 4, p. 118) . 

Faunas of the Bangor Limestone are characteristic Mississippian forms; however, Butts ( 1926, 

p. 206; 1927, p. 13) reported both Mississippian and 

Pennsylvan.ian fossils from the Parkwood. A Mississippian fauna .in the Bangor and the reported 

Pennsylvanian fossils in the Parkwood seem incompatible with the observation that the Parkwood and 

Bangor formations intertongue both in the Black 

Warrio•r basin and in Appalachian synclines. Possibly the differences in the faunas re•flect the dif-
. ,.. MISSISSIPPIAN ··STRATIGRAPHY OF ALABAMA 117 

-·--·----------------- --.;.;;------/~- \ ::::;MONTEAGLE- , · 

' .::::::·BANGayRr/ '/ I .::::::: .' lv 

·Approximate limit of preservation .::::::::: <;~ .• · 

I FLOYD 

...... 

~ 1 ,...-

pI 

I 

I 

I 

I 

I 

I PARKWOOD 

~ ... ~ /? // 

/ 

\ 

\ 

I 

\ 

E \ 

\ 

\ 

\ 

I 

\ 

CARBONATE 

SHELF 

BANGOR 

\ 

\ 

I 

\ 

F \ 

\ 

\ 

\ 

I 

\ 

H \ 

\ 

\ 

·, 25 50 75 100 KILOMETERS 

Fort Payne-Tuscumbia, B: Floyd/lower Pride Mountain/Monteagle. C. Floyd/middle Pride Mountain/Monteagle. D. 

Floyd/upper Pride Mountain/Monteagle. E. Floyd/Hartselle/Monteagle-Bangor. F. Lower Parkwood (example of prograding sandstone) /Bangor. G. Parkwood (example of limestone tongue) /Bangor/lower Pennington. H. Upper Parkwood (example of prograding sandstone) /Bangor/upper Pennington. 

ferent sedimentary environments. Outcrops along 

the C31haba syncline offer the best opportunity for 

detailed study of the relative importance of paleoeco,logy and biostratigraphic position in controlling 

variations in local fossil faunas of the Bangor and 

Parkwood. Fossilferous units include the limestone of the Bangor as well as both shale and sandstone ocf the Parkwood. Along the Cahaba syncline, 

stratigraphic positions o.f the different faunas. may 

be mapped accurately with respect to. both vertical 

succession and facies. 1bounda:ries. Detailed studies 

could provide understanding of time-dependent 

variations in the faunas o.f :both the carbonate and 

clastic facies as well as ti-me correlation between the 

faunas of the two intertonguing fades. The problem 

of biostratigraphic identification of the Mississippian-Pennsylvanian boundary is a common one, and 

the outcrops ·along the Oahaba syncline provide an 

opportunity fo·r a significant contribution to understanding of that problem. 

DEPOSITIONAL AND TECTONIC FRAMEWORK 

The Fort Payne-Tuscumbia chert and cherty limestone suocession reflects deposition on a broad shallow-marine· shelf on the East Warrior platform 
I18 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

(fig. 5A). On the southwest in the Bl:ack Warrior 

basin, the Fort Payne-Tuscumbia is thinner, and 

vertical differentiation of two rock types is indistinct. Thinning off the platform may be a result of 

less rapid accumulation of bioclastic sediment in 

lower energy environments, and possi.bly the thinner 

section in the basin represents the same time span 

as the thicker section on the platform. Alternatively 

thinning may be a result of lateral gradation of the 

upper part of the Tuscumbia into the northeast .. 

prograding clastic facies. Another suggested alternative is that thinning results from an unconformity at the top of the Tuscumbia (Welch, 1959). 

Toward the southeast, the Fort Payne-Tuscumbia 

thins off the East Warrior platform into Appalachian synclines, and the entire cherty unit pincJhes 

out locally. Interbeds of limestone in the Floyd 

Shale suggest that the Fort Payne-Tuscumbia 

grades vertically and laterally southeastward into 

the clastic facies. Higher on the East Warrior platform toward the northeast, dolostone interbeds are 

more common. In northwest Georgia, the dolostone 

is associated with quartz geodes containing relict 

anhydrite (Chowns, 1972, p. 90). The suggested 

sabkha environment (Chowns, 1972, p. 90) is on the 

presumably highest supratidal part of the platform. 

The oolitic and bioclastic limestones of the Monteagle and Bangor indicate high-energy environments on a shallow-marine shelf (fig. 5). The massive crossbedded units are lraterally discontinuous, 

and interbeds of lime mudstone and shaly limestone 

suggest deposit.ion in protected areas between carbonate bars. The prolific marine invertebrate fauna 

includes ·corals, echinoderms, brachiopods, and bryozoans. Thick units of oolitic limestone in the Monteagle are limited to northeastern Alabama, but in 

the Bangor, massive linear units of oolitic limestone 

across the southwestern part of the East Warrior 

platform suggest a high-energy shelf-edge system 

(fig. 5G). Southwest of the oolite shelf, the Bangor 

Limestone tongues reflect lower energy environments in the Black Warrior basin, and components 

of a shelf, ramp, and basin sequence can be identified (Scott, 1976, p. 720). The southwestward gradation from carbonate to clasti'c facies extends into 

the Appalachian synclines, but the limestones suggest low·er energy environments, presumably in 

deeper water in contemporaneous synclines· off the 

southeastern ed'ge of the shelf. 

The clastic facies on the southwest is composed of 

a prograding succession of prodelta shales (Floyd) 

and delta-front sandstones· (Parkwood). The clastic 

facies makes up most of the Mississippian System 

in the Black Warrior basin and along the deeper 

Appalachian synclines. A tongue of shale and sandstone (Pride Mountain and Hartselle) extends from 

the lower part of the clastic facies northeastward 

onto the East Warrior platform, where the Mississippian is otherwise dominated by the carbonate facies. 

The Pride Mountalin and Hartselle include four 

sandstone units that are broadly linear in distribution and that trend southeast across the southwestern part of the East Warrior platform (figs. 5B, 5C, 

5D, and 5E). The sandstone units in the Pride 

Mountain contain limestone beds and locally grade 

laterally to limestone. Toward the northeast, the 

Pride Mountain sandstones grade into marine shales 

that, farther northeast, are· replaced by oolite bars 

of the Monteagle (figs. 5B, 5C, and 5D). In contrast, the Hartselle Sandstone extends eastward and 

pinches out within the carbonate facies. Toward the 

southw·est, the linear sandstones pinch out into gray 

shale of the Floyd. N orthwestw,ard along trend, the 

linear s·andstones extend across the platform edge 

and into the Black Warrior basin in Mississippi,· 

where the sandstones are more blanketlike 

(Thomas, 1972:b, p. 98; 1974, p. 196). The linear 

sandstones end southeastw.ard along trend in the Appalachian fold and thrust belt (figs. 5B, 5C, 5D, and 

5E) . Although that aspect of sand distribution may 

be a function of the sediment-dispersal system, evidently the linear sandstones were limited mainly to 

the shallow platform and did not extend far southeast into the contemporaneously subsiding Appalachian synclines. Contemporaneous slump faults in 

the basal beds of the Hartselle Sandstone indicate 

paleoslopes in the direction of structural dip on both 

limbs of the Birmingham antidinorium (Thomas, 

1968). 

Sedimentary structures in the Pride MountainHartselle sandstones indicate a variety of depositional processes characterized by high-energy environments. Tidal channels are indicated by local rockclast conglomerate. Lateral and vertical associations 

of rock types and sedimentary structures ih the 

Hartselle of northwestern Alabama indicate th~ effects of both longshore and tidal currents (Beav~rs 

and Boone, 1976, p. 12). Tree fossils, especially the 

stump reported from the Harts·elle (McCalley, 1896, 

p. 171-176), suggest partly forested areas. Shells of 

marine organisms are concentrated locally in the 

high-energy sands. Near the ,eastern· limit of Hartselle Sandstone, sandstone and oolitic bioclastic lime-
MISSISSIPPIAN STRATIGRAPHY OF ALABAMA 119 

stone are jnterlaminated in crossbedded highenergy bar deposits. 

The linear shapes of the Pride Mountain-Hartselle sandstone units and distribution of the sandstone relative to that of the major carbonate and 

clastic facies suggest deposition as a succession of 

bar or barrier sand complexes (Thomas, 1972a, 

p. 105; 197 4, p. 200). The linear sandstones are 

within a clastic tongue that extends northeastward 

from the lower part o.f the Floyd Shale, and the 

Floyd is overlain by the Parkwood Formation, 

which contains northeastwardly prograding deltaic 

sandstones. However, the Parkwood sandstones are 

evidently younger than the Pride Mountain and 

Hartselle sandstones, and the source of the Pride 

Mountain and Hartselle sands is not conclusively established. Swann (1964, p. 653) suggested that sand 

supplied through the Illinois basin by the Michigan 

River system prograded as far south as the Black 

Warrior basin. Regardless of the source of sand, the 

Pride Mountain-Hartselle sandstones are distributed 

along the boundary between the regional carbonate 

and clastic facies, and the orientation of the linear 

sandstones suggests a high-energy environment near 

the southwestern edge of the East Warrior platform. 

The more blanketlike sandstones in the Black Warrior basin in Mississippi are interpreted to be 

marine sands. More precise definition of .environments represented by the linear sandstones will result from better understanding of their relation to 

facies in the Floyd Shale on the southwest, of the 

system of sand supply, and of sedimentary features 

within the sandstones. 

Along the Coosa synclinori urn, the Bangor Limestone Tongue in the Floyd Shale demonstrates intertonguing of the clastic and carbonate facies. Farther 

east in Geo·rgia, the clastic sequence contains two; 

limestone tongues-a tongue of Bangor Limestone 

and a lower limestone tongue in the Floyd Shale in 

the stratigraphic position of the Tuscumbia and 

(or) Monteagle. The lower limestone may extend 

southwest as far as the northeast end of the Coosa. 

deformed belt, but there it evidently grades southwestward to the shale facies in a pattern similar to 

the southwestward gradation from Monteagle Limestone to shale on the East W ani or platform. 

Along the Pickens-Sumter anticline south of the 

Black Warrior basin in the subsurface in west-central Alabama, the lower part of the Floyd Shale includes limestone beds (figs. 5B, 5C, and 5D) that are 

in the same stratigraphic position as the sandstone 

units in the Floyd and Pride Mountain on the East 

Warrior platform, but no genetic relationship is apparent. Possibly the limestones denote a local carbonate shoal associated with a contemporaneous 

Pickens-Sumter anticline; alternatively, they may 

mark the northern edge of a more extens·ive carbonate shelf that extends farther south into the fold 

and thrust belt. 

The Floyd Shale constitutes a prodelta mud deposit that grades upward into deltaic sediments of 

the Parkwood Formation. Parkwood sandstones are 

interpreted to be delta-front and distributary sediments that are interbedded with marine-bay shale 

and mudstone (figs. 5F, 5G, and 5H). Distribution 

of the sandstones suggests northeastward prograding from a sediment source southwest of the Black 

Warrior basin of western Alabama and eastern Mississippi. The more sandy part of each of the Parkwood cydes reflects a major episode of delta prograding. The shaly parts of the Parkwood include 

interdistributary-bay sediments and contain extensive tongues of the Bangor Limestone which denote 

transgression and delta destruction. Bay-fill fine 

clastic sediments generally grade upward to distributary-front sandstones. A few of the sandstones 

were deposited on scoured surfaces evidently in 

small distributary channels. Most Parkwood sediments are in the marine-delta front and interdis-· 

tributary-bay facies; little of the succession suggests 

delta-plain deposits. Sedimentary features and fossil 

faunas of the Parkwood suggest a near-shore marine ·environment (Whisonant, 1970, p. 141). Interdistributary marsh deposits in the locally carbonaceous uppermost beds o.f the Parkwood 

represent the highest preserved part of the delta 

complex. Later Parkwood sandstones are more extensive than older ones, and the upper part o.f the 

Parkwood progrades northeastward onto the southwestern edge of the East Warrior platform. The 

Parkwood grades upward into conglome·rate, sandstone, shale, and coal of the Pottsville Formation, 

which progrades northeastward farther than the 

Parkwood and overlies the Bangor Limestone on the 

East Warrior platform. 

The Floyd-Parkwood clastic facies is much thicker 

and extends farther northeast along the Appalachian synclines than in the Black Warrior basin and 

East Warrior platform. The same general pattern 

of cyclical delta progradation and transgression is 

recognizable within the Parkwood Formation in the 

synclines. The greater thickness and extent of the 

I 

clastic facies .suggest that the synclines subsided 

contemporaneously with Mississippian deposition 
I20 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

and that the structural troughs provided channels 

along which sediment was selectively transported 

northeastward. Distribution of sandstone in the 

Parkwood in the Cahaba syncline does not parallel 

that in the Coosa synclinorium. Sections in the Cahaba syncline generally ~contain about 50 percent 

more sandstone than sections ac·ross strike in the 

Coosa synclinorium; however, the total thickness of 

the section in the Coosa synclinori urn averages 25 

percent greater than that in the Cahaba syncline. 

These distribution patterns suggest contemporaneous downwarp of two separate synclines. Northeastward prograding of the Parkwood, northeastward decrease in sandstone, and southwestward 

thinning of the Bangor Limestone are co.mpatible 

with the interpretation that the clastic s·ediment was 

transported longitudinally northeastward along the 

synclines from a source on the southwest. Thus, a 

regionally consistent pattern of northeastward progradation and a provenance ·On the southwest are indicat·ed for the Floyd-Parkwood clastic sediments in 

both the Black Warrior basin and the Appalachian 

syndines (Thomas, 1972a; 197 4, p. 203). 

Other interpretations have been propos.ed for location of the provenance and dispersal system of 

Parkwood clastic sediments. Crossbedding in Parkwood sandstones in the Cahaba and Coosa synclines 

shows significant modes toward both the northnorthwest and the south-southwest (Whisonant, 

1967, p. 1871). Citing the interpretation of crossbedding and heavy-mineral data indicative of a 

m.etasedimentary provenance, Whisonant (1967, p. 

1872) postulated possible northwestward transport 

from a sediment source on the southeast in the Appalachian Piedmont. However, that provenance location and transport direction are not supported by 

the regional distribution of the Parkwood clastic 

facies and the equivalent carbonate facies. Furthermore, Carrington (1967, 1972) concluded that some 

metas·edimentary rooks in the Piedmont represent 

Parkwood-equivalent sediments. 

Another alternative for the Parkwood dispersal 

syste.m is derived from regional studies of the Michigan River system deltaic s~ediments in the Illinois 

basin (Swann, 1964). Swann (1964, p. 653) suggested that at some times the Michigan River system p·rograded southward from the Illinois basin 

and transported sediment to the northeastern edge 

of the Ouachita trough and the western part of the 

Black Warrior basin. Welch (1971) concluded that 

Mississippian sandstones in the Black Warrior basin 

were supplied from the north, probably through the 

Illinois basin. That interpretation requires that 

Parkwood deltaic sediments prograded southward or 

southeastward into the Black Warrior basin. 

In no~theastern Alabama, the Pennington Formation constitutes a clastic facies that prograded 

southwestward onto the carbonate-shelf sediments 

of the Bangor Limestone (figs. 5G, 5H). Evidently 

the location of the facies boundary was not influenced by ·a shelf ·edge. The dolostone unit in the 

lower Pennington suggests a supratidal shelf that 

was subsequently covered by shallow-marine fine 

clastic sediments (fig. 5G). The shallow-marine 

mudstone and limestone are supplanted farther east 

by sandstone, shale, and carbonaceous beds that represent marine bays, small bars, and coastal lagoons 

and marshes (fig. 5H). Lateral gradation of a coal 

bed to brachiopod-bearing siderite, and interfingering of bar sandstone with marine shale, suggest 

small-scale environmental features on a plain nearly 

at sea level. The Pennington is overlain by massive 

sandstones of the Pottsville Formation which constitute a coarser fraction of the southwest-prograding clastic complex. The Pottsville extends beyond 

the Pennington clastic succession and overlies the 

Bangor Limestone fa·rther west. 

Provenance and dispersal studies of Pottsville 

sandstones in Alabama hav,e implications. for interpretations of underlying Mississippian clastic sediments. Crossbedding in the basal Pottsville sandstones of northeastern Alabama indicates transport 

toward the west or southwest (Tanner, 1959, p. 224; 

Schlee, 1963, p. 1446; Chen and Goodell, 1964, p. 70; 

Metzger, 1965, p. 27). This direction is most persistent in northeastern Alabama, where the Pottsville overlies the Pennington clastic facies, and beyond the western limit of the Pennington, where the 

Pottsville progrades over the Bangor Limestone. 

In Northwestern Alabama, crossbedding orientation 

is more diverse (Schlee, 1963, pl. 1; Metzger, 1965, 

p. 27). On the basis of geometry of beach and barrier-island sandstones of the basal Pottsville, Hobday (1974, p. 223) concluded that two sediment supply systems (from the northeast and from the 

south) merged in north-central Alabama. Compositional variation in Pottsville sandstones of central 

Alabama indicates a source on the south (Davis and 

Ehrlich, 197 4, p. 177). These interpretations may 

be assembled to suggest that the Pottsville of Alabama includes two components that converged on 

the East Warrior platform from the northeast and 

from the south. Thus, the northeast-prograding 

Parkwood continues upward into one component of 
MISSISSIPPIAN STRATIGRAPHY OF ALABAMA 121 

the Pottsville and the southwest-prograding Pennington continues upward into the other component. 

Mississippian clastic rocks in Alabama are parts 

of two regional clastic wedges in the AppalachianOuachita structural system (Thomas, 1974, p. 206; 

1977). The Floyd-Parkwood-Pottsville clastic sequence is part of a large-scale clastic wedge centered 

on the Ouachita structural salient. The Mississippian-Pennsylvanian clastic sequence extends from 

Alabama westward in the subsurface across the 

Black Warrior basin in Mississippi toward the 

Ouachita Mountains, where the thickness is much 

greater than that in the Black Warrior basin. The 

wedge includes a lower unit of shale (Stanley of 

Ouachita Mountains; F.loyd of Black Warrior basin) 

and an overlying succession of .sandstone and shale 

(Jackfork-Atoka of Ouachita Mountains; ParkwoodPottsville of Black Warrior basin). Depositional 

features of the Ouachita sediments indicate a deepwater flysch environment (Cline, 1960, p. 100; 1970, 

p. 100), whereas the thinner sequence on the east 

in the Black Warrior basin comprises a prograding 

delta system (Thomas, 1974, p. 200). The indicated 

dispersal pattern suggests a common source area 

southeast of the Ouachitas and southwest of the 

Black Warrior basin (Thomas, 1974, p. 202; 1976, p. 

337). 

Similarly, the southwest prograding Pennington 

clastic facies in northeastern Alabama is evidently 

at the southwestern fringe of a large-scale clastic 

wedge centered farther northeast (Thomas, 1977, 

p. 1258). The center of that wedge appears to be 

within the Tenness,ee structural salient, probably in 

southwestern Virginia, where the Pennington is 

much thicker and coarser than it is in Alabama. 

Regional facies relations indicate that Upper Mississippian clastic sediments prograded southwestward 

along the App,alachians in Tennessee (Ferm and 

others, 1972, fig. 3). In Alabama, the Pennington at 

the fringe of the wedge grades southwestward into 

the carbonate facies. The overlying southwest-prograding Pottsville clastic sequence extends farther 

west and southwest above the Bangor Limestone. 

Mississippian-Pennsylvanian clastic wedges prograde from southwest and northeast onto the shallow-marine carbonate facies in the Bangor Limestone in north-central Alabama. Each of the two 

converging clastic wedges is centered on a regional 

structural salient (Ouachita and Tennessee salients), and the intervening carbonate facies is within 

a regional structural recess in Alabama (Thomas, 

1977). 

The Black Warrior basin and East Warrior platform are reflected in distributions of thickness and 

facies throughout the Mississippian System. However, the Fort Payne-Tuscumbia rocks show gradual southwestward change, whereas the younger 

Bangor and Parkwood facies reflect a relatively 

abrupt change at the platform edge. Possibly the 

East Warrior platform and the western edge of the 

platform became more pronounced in the later Mississippian. Facies and thickness of the Mississippian 

System indicate contemporaneous subsidence of the 

Appalachian synclines southeast of the East Warrior platform. 

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-- 1963b, Pennsylvanian nomenclature in northwest 

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E57. 

Davis, M. W., and Ehrlich, Robert, 1974, ·Late Paleozoic 

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122 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

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--- 1972, The lower Carboniferous ammonoid genus 

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Jones, W. B., 1928, Summary report on the building limestones of the Russellville district: Alabama Geol. Survey Circ. 8, 36 p. 

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McKinney, F. K., 1972, Nonfenestrate Ectoprocta (Bryozoa) 

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Metzger, W. J., 1965, Pennsylvanian stratigraphy of the 

Warrior basin, Alabama: Alabama Geol. Survey Circ. 

30, 80 p. 

Milici, R. C., 1974, Stratigraphy and depositional environments of Upp.er Mississippian and Lower Pennsylvanian 

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in Briggs, Garrett, ed., Carboniferous of the southeastern United States: Geol. Soc. America Spec. Pap.er 

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chart 6.] 

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Bull., v. 74, ·no. 12, p. 1439-1451. 

Scott, G. L., 1976, Deposition, facies patterns, and hydrocarbon potential of Bangor Limestone (Mississippian), 

northern Black Warrior basin, Alabama and Mississippi 

[abs.]: Am. Assoc. Petroleum Geologists Bull., v. 60, 

no. 4, p. 720. 

Smith, E. A., 1879, Report of progress for 1877 and 1878: 

Montgomery, Ala., Alabama Geol. Survey, 138 p. 

--- 1890, Geological structure and description of the valley regions adjacent to the Cahaba coal field, Pt. 2 of 

Squire, Joseph, Re·port on the Cahaba coal field: Alabama Geol. Survey [Spec. Rept. 2], p. 133-180. 

--- 1892, Sketch of the geology of Alabama: Birmingham, Ala., Roberts and Son, 36 p. 

--- 1894, Geological map of Alabama: Montgomery, Ala., 

Alabama Geol. Survey Map 1. 

Swann, D. H., 1964, Late Mississippian rhythmic sediments 

of Missis1sippi Valley: Am. Assoc. Petroleum Geologists 

Bull., v. 48, no. 5, p. 637-658. 

Tanner, W. F., 1959, The importance' of modes in crossbedding data: Jour. Sed. Petrology, v. 29, no. 2, p. 

221-226. 

Thomas, W. A., 1968, Contemporaneous normal faults on 

flanks of Birmingham anticlinorium, central Alabama: 

Am. Assoc. Petroleum Geologists Bull., v. 52, no. 11, 

pt. 1, p. 2123-2136. 

--- 1972a, Mississippian stratigraphy of Alabama: Alabama Geol. Survey Mon. 12, 121 p. 

--~ 1972b, Regional Paleozoic stratigraphy in Mississippi 

between Ouachita and Appalachian Mountains: Am. 

Assoc. Petroleum Geologists Bull., v. 56, no. 1, p. 81-106. 

--- 1973, Southwestern Appalachian structural system 

beneath the Gulf Coastal Plain: Am. Jour. Sci., v. 273-

A, p. 372-390. 

--- 1974, Converging clastic· wedges in the Mississippian 

of Alabama, in Briggs, Garrett, ed., Carboniferous of 

the southeastern United States: Geol. Soc. America ·Spec. 

Paper 148, p. 187-207. 

--- 1976, Evolution of Ouachita-Appalachian continental 

margin: Jour. Geology, v. 84, p. 323-342. 

--- 1977, Evolution· of Appalachian-Ouachita salients 

and recesses from reentrants and promontories in the 

continental margin: Am. Jour. Sci., v. 277, p. 1233-

1278. 

Upshaw, C. F., 1967, Pennsylvanian palynology and age relationships in the Warrior basin, Alabama, in A field 

guide to Carboniferous detrital rocks in northern Alabama-Geol. Soc. America, Coal Div., 1967 Field Trip: 

University, Ala., Alabama Geol. Soc., p. 16-20. 

Wanless, H. R., 1975, Appalachian region, in McKee, E. D., 

and Crosby, E. J., coordinators, Introduction and regional analyses of the Pennsylvanian System, Pt. 1 of 

Paleotectonic investigations of the Pennsylvanian System in the United States: U.S. Geol. Survey Prof. Paper 

853, pt. 1, p. 17-62. 

Welch, S. W., 1958, Stratigraphy of Upper Mississippian 

rocks above the Tuscumbia Limestone in northern Alabama and northeastern Mississippi: U.S. Geol. Survey 

Oil and Gas Inv. Chart OC-58. 

--- 1959, Mis1sissippian rocks of the northern part of· 

the Black Warrior basin, Alabama and Mississippi: 

U.S. Geol. Survey Oil and Gas Inv. Chart OC-62. 

--- 1971, Awakening the Black Warrior basin: Oil and 

Gas Jour., v. 69, no. 4, p. 155-163. 

Whisonant, R. C., 1967, Direction of upper Paleozoic currents, central Alabama: Am. Assoc. Petroleum Geologists Bull., v. 51, no. 9, p. 1870-1873. 

--- 1970, Paleoecology ~nd depositional environments of 

the Parkwood Formation, central Alabama: Southeastern Geology, v. 12, no. 2, p. 135-149. 

Wilson, R. L., 1965, Pennsylvanian stratigraphy and sedimentation of the northern part of Sand Mountain, Alabama, Georgia, and Tennessee: Knoxville, Tenn., Univ. 

Tennessee, unpub. Ph.D. dissert. 
PENNSYLVANIAN STRATIGRAPHY OF ALABAMA 

CONTENTS 

Page 

Abstract ---------------------------------------------------------------- l2~ 

Introduction ------------------------------------------------------------- 23 

Distribution -------------------------------------------------------------- 23 

Stratigraphy ------------------------------------------------------------- 24 

Subinterval A1 ------------------------------------------------------- 28 

Plateau field ----------------------------------------------------- 29 

VVarrior field ---------------------------------------------------- 30 

Cahaba field ----------------------------------------------------- 30 

Coosa field ------------------------------------------------------- 30 

Subinterval A2 ------------------------------------------------------- 31 

VVarrior field ---------------------------------------------------- 31 

Cahaba field ----------------------------------------------------- 32 

Northeastern Coosa field ------------------------------------------ 32 

Southwestern Coosa field ----------------------------------------- 32 

Interval B ---------------------------------------------------------- 33 

VVarrior field --------------------------------------------------- 33 

Cahaba field ----------------------------------------------------- 33 

Coosa field ------------------------------------------------------- 34 

Coal resources ----------------------------------------------------------- 34 Selected references _ _ _ _ __ _ _ _ __ _ __ _ __ _ _ _ __ ___ __ _ __ _ _ _ _ _ _ _ ____ _ __ __ _ __ __ _ __ _ 35 

ILLUSTRATIONS 

FIGURE 6. Columnar sections showing position of coal beds and sandstone members of the Pottsville formation 

Page 

in Alabama-----------------------------------·-------------------------------------------- 126 

TABLE 

TABLE 1. A list of selected taxa. from Pennsylvanian strata of the VV arrior basin, Alabama 127 

III 
THE MISSISSIPPIAN AND PENNSYLVANIAN (CARBONIFEROUS) SYSTEl'viS 

IN THE UNITED STATES-ALABAMA AND MISSISSIPPI 

PENNSYLVANIAN STRATIGRAPHY OF ALABAMA1 

By W. EvERETT SMITH 2 

ABSTRACT 

Pennsylvanian strata crop out in the northern half of 

Alabama and underlie ~uch of the State at depth. Folding 

and faulting and subsequent erosion of the southern Appalachians have resulted in isolation of several outcrop areas 

termed the Warrior, Coosa, Cahaba, and Plateau coal fields. 

General subdivisions of the rock sequence have been made 

on the basis of coal groups, floral zones, and lithology. The 

most recent classification system was proposed by H. R. 

Wanless, who used the terminology subinterval A1, and subinterval A~ and interval B (youngest). Major rock types 

include sandstone, siltstone, shale, mudstone, underclay, and 

bituminous coal. The c-oal is generally ranked as high volatile A to low volatile and ranges from 3 to 15 percent of 

ash and less than 2 percent of sulfur. Estimates of State 

coal reserve's range from 13.9 billion short tons to 35.5 billion .short tons. The several coal fields are generally con- _ 

sidered to have been part of a major depositionaJ basin 

during Pennsylvanian time; however, the fields VarY greatly 

in sediment thickness and lithologi~ pattern-s, and most coal 

beds have not been correlated· with certainty between the 

fields. Most of the Penn~ylvanian rocks in Alabama probably are early (Pocahontas) and middle ( N·ew River) Pottsville in age. Time transgression of lithologic units in a 

northeastern direction appears likely, sediment sources being primarily to the south and east. 

INTRODUCTION 

This paper summarizes basic geologic information 

and concepts thus far acquired on Pennsylvanian 

rocks in Alabama. Because of its summary nature, 

the paper makes all too brief reference to the geologic data and only passing comment or inference on 

many fundamental concepts and issues. The published information on the Alabama Pennsylvanian 

System is relatively sparse, and important published 

reports are no·w practically inaccessable to many investigators. The writer wishes to call attention early 

in this discussion to the recently published comprehensive work on the Pennsylvanian System in the 

1 Publication approved by the State Geologist. 2 Geological Survey of Alabama, P. 0. Drawer 0, University, Alabama 36486. 

United States by McKee, Crosby, and others (1975) 

which includes discussions of Pennsylvanian rocks in 

the southern Appalachians by Wanless (1975). 

Few geologists have given sufficient attention to 

Pennsylvanian rocks in Alabama to acquire insight 

to the whole system. It was only in the 1870's that 

interest in the coal beds in the Pennsylvanian focused 

attention on these rocks, and from this early period 

until the early 1900's, geologic investigations of the 

Pennsylvanian rocks were essentially descriptions of 

the coal-bearing horizons. In this respect, Henry 

McCalley (1891, 1898, 1900) did much of the first 

field investigations and prepared descriptive reports. 

Prouty (1912) and Butts (1907, 1910, 1911, 1926, 

1927, 1940) were also early contributors. In recent 

years, Rothrock (1949), Culbertson (1964), Ferm 

(Ferm and Ehrlich, 1967; Horne, Ferm, and others, 

1976), Metzger (1961, 1965), and Thomas (1972) 

have contributed information on stratigraphy, paleoecology, and tectonism. Recently, many geologists 

again have given attention to local stratigraphy of 

Pennsylvanian rocks in connection with exploration 

for and development of coal. 

The stratigraphic nomenclature used in this paper 

has not been reviewed by the Geologic Names Committee of the U.S. Geological Survey. The nomenclature used here conforms with the current usage 

of the Geological Survey of Alabama. 

DISTRIBUTION 

Rocks of Pennsylvanian age crop out in northern 

Alabama and underlie much of the State at depth. 

Folding and faulting and subsequent erosion of th~ 

southern Appalachians have resulted in isolation of 

several different outcrop areas which are herein referred to as coal fields. 3 Four major fields are the 

3 Some geologists now refer to these areas as coal basins or use the term "basin" synonymously with the term "field," although it should be 

recognized that the two terms in the strictest sense carry different connotation~<. 

123 
124 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Warrior, Plateau, Coosa, and Cahaba. 

The Warrior field (Mellen, 1947; McCalley, 1898, 

1900; Metzger, 1965; Wanless, 1975) is the largest 

outcrop area of Pennsylvanian rocks in Alabama, 

comprising approximately 12,680 km2 in the northwestern quarter of the State. Mellen (1947) proposed that the Warrior basin be defined as a triangular area of approximately 35,000 sq mi of normal Paleozoic sediments bounded on the north by 

Tennessee, on the southeast by the southwestplunging Appalachian Mountains of Alabama, and 

on the southwest by the buried Ouachita Mountains 

of eastern Arkansas and northern Mississippi. Mellen (1947) noted that this area, whether or not correctly described as a basin, has been one of great 

negative epeirogenic tendency. 

Physiographically, the area of the Warrior field 

not covered by Coastal Plain sediments is part of the 

Cumberland Plateau. The field is bounded on the 

north by the southern flank of the Nashville dome 

and on the southeast by folds and thrust faults of 

the Sequatchie Valley anticline and faulted anticlines of the Bessemer-Birmingham valley. On the 

southwest, in the subsurface the field may be limited 

by concealed thrust faults (Wanless, 1975; Kidd, 

1976). Strata of the Warrior field dip south and 

thicken in the same direction. The field is structurally less complex than other areas in the State, but 

gentle folds, large-scale joint features, and normal 

and reverse faults of significant magnitude are 

found in the field. Sediments in the Warflior field 

include eight4 coal groups ha,ving more than 20 

minable beds in some part of the field. Gas is being 

produced from Missi,ssippian horizons underlying 

the field in northwestern Alabama. 

The Plateau field is the name given to several 

coal-bearing plateau areas in northeast Alabama 

similarly divided by eroded anticlines. The field in-

. eludes more than 11,660 km2 including Lookout 

Mountain, Blount Mountain, Altoona Mountain, Sand 

Mountain (Raccoon Mountain), West Sand Mountain, and many small remnant mountains in extreme 

northeastern Alabama. Some geologists also include 

in the Plateau field certain areas that other geologists consider the northern part of the Warrior 

field, particularly those outcrop areas of coal beds 

below the Black Creek coal bed. The Pennsylvanian 

4 Six coal groups were recognized by McCalley (1900), including the 

Brookwood, Gwin, Cobb, Pratt, Horse Creek (including the Mary Lee 

coal), and Black Creek. In recent years, the Utley coal group has been 

recognized. In addition, the term "J group" has been used by some 

geologists and miners, in reference to the J, K, L, and M beds which 

are below the Black Creek coal group in the Blue Creek basin. 

rocks in the Plateau region contain more than 25 

coal beds. 

The Coosa field is a folded and faulted synclinorium, which includes approximately 725 km2 • It is 

about 96 km long, about 8 km wide and contains 

more than 15 coal beds of mineable thickness. The 

Cahaba field southeast of Birmingham includes an 

area of approximately 906 km2 and contains about 

60 coal beds. The several coal fields are considered 

to have been more or less continuous during Pennsylvanian time; however, the fields vary greatly in 

rock thickness and lithologic patterns, and most coal 

beds have not been correlated with certainty between the fields. 

In the subsurface, Pennsylvanian rocks in Alabama have been identified as far south as Marengo 

County (Kidd, 1976). South of central Marengo 

County, these rocks have not been identified; they 

are apparently covered by thrust-faulted older rocks 

(Kidd, 1976). This thrust faulting is hypothesized 

to have been generally toward the northwest and 

generally along a line extended from southern Bibb 

County through southern Sumter County and into 

Mississippi. Kidd (1976) also indicated thrust faulting of older sedimentary rocks over Pennsylvanian 

rocks in southern Greene and northern Sumter 

Counties. Kidd's map of the configuration of the top 

of. the Pennsylvanian rocks in west-central Alabama 

(Kidd, 1976) shows a dip to the southwest into Mississipi. 

South of the Appalachian Valley and Ridge province in Alabama, Pennsylvanian-age rocks appear 

to be terminated, possibly by thrust-faulted older 

sedimentary rocks or by metamorphic rocks. 

STRATIGRAPHY 

White, as reported by Butts (1927), showed that 

the lower-middle Pottsville boundary in West Virginia is approximately at the horizon of the Black 

Creek coal in the Alabama Warrior coal field. Read, 

as reported by Metzger (1965), identified and determined the ages of plant remains in the uppermost 

exposed beds of the Warrior field (above the guide 

coal seams) to be latest early New River. Thus, most 

of the Pennsylvanian rocks in Alabama probably 

are early (Pocahontas) and middle (New River) 

Pottsville in age. Palynology studies by Upshaw 

(1967) are in accord with these age assignments, 

although Upshaw (1967) pointed out that precise 

age equivalents cannot be established because detailed palynological studies of Pocahontas and New 

River type sections have not been made. Upshaw 
PENNSYLVANIAN STRATIGRAPHY OF ALABAMA 125 

further suggested that beds older than the lowest 

Pottsville of the type area (and older than the lowest Morowan of Arkansas) may be included in the 

Pottsville Formation of Alabama. West of Alabama, 

in the subsurface of Mississippi, beds of Kanawha 

age are included with the Pottsville unit and contain 

abundant Laevigatosporites ovalis in association 

with Endosporites globifermis (Upshaw, 1967, p. 

18). The studies by Upshaw show time transgression of lithologic units to be all in a northeastern 

direction. Ferm and Ehrlich (1967) supported this 

concept of time transgression of lithologic units. 

Butts ( 1926, p. 206) assigned all Pennsylvanian 

rocks in Alabama (except those of the Erin Shale) 

to the Pottsville Formation. He considered the 

Parkwood to be part of the Mississippian sequence 

and placed the base of the Pennsylvanian in Alabama at the base of the Brock coal bed, which he 

judged to be at a horizon in the lower Pottsville 

Formation as low as the lowest Pennsylvanian 

throughout the Appalachian coal fields. He noted 

however that the upper Parkwood may include a mixture of Pennsylvanian and Mississippian fossils, and 

that no sharp line of division appears within the 

Parkwood that would serve as a division line between the Mississippian and Pennsylvanian (See 

discussion by Thomas, this chapter for detailed discussions of Mississippian-Pennsylvanian boundary.) 

Culbertson ( 1963, p. 49 ; 1964) defined the top of the 

Parkwood as being at the base of sandstone members at the base of the Pottsville Formation, including the Shades Sandstone Member in the Cahaba 

and Coosa fields, the Boyles Sandstone Member in 

the Warrior field, and the Lower Conglomerate (McCalley, 1891) in the Plateau field (fig. 6). 

Wanless ( 1975) considered the upper part of the 

Parkwood Formation to be within the Lower Pennsylvanian. According to Butts (1926) and Wanless, 

the Erin Shale (phyllite in the metamorphic Talladega Series) is apparently of Pennsylvanian age, 

although its relationship to other Pennsylvanian 

rocks is undetermined. 

The Pennsylvanian Subcommittee, R. C. Moore, 

Chairman (Moore and others, 1944), has assigned 

most of the Pennsylvanian rocks in Alabama to the 

Morrow Series (Lower Pennsylvanian) which includes Read's (according to Moore, and others, 

1944) floral zone of N europteris pocahontas and 

M a'riopteris eremopteroides, floral zone of M ariopteTis Pottsvillea and Aneimites, and floral zone of 

MaTiopteris pygmaea. The subcommittee assigned 

uppermost Pennsylvanian rocks in the Cahaba and 

I 

Warrior fields to the Kanawha Series (which include 

Read's (according to Moore and others, 1944) floral 

zone of Cannophyllites and floral zone of N europteris 

tenuifolia) . 

McCalley ( 1900) proposed a classification of the 

Pennsylvanian rocks of Alabama based on six coal 

groups, using the lowest coal within each group as 

the base. Metzger ( 1965) proposed a similar system 

of subdivision but suggested that the most persistent coal bed in each group rather than the lowermost bed be used as the group market. Neither McCalley or Metzger assigned specific names to the 

various subdivisions, although Metzger, to facilitate 

discussion of the sediments, designated the units 

from oldest to youngest as stratigraphic intervals 

A, B, C, D, E, F, and G. 

Wanless' ( 1975) discussion of the Alabama Pennsylvanian, which is a part o.f a comprehensive discussion of the Pennsylvanian System of the United 

States (McKee, Crosby, and others, 1975) uses the 

classification system set up in that report and classifies Alabama's Pennsylvanian rocks as interval A 

(containing subintervals A1. and A2) and interval B 

(youngest). This classification system has been used 

in the present discussion. 

Fossils in the Pennsylvanian sequence of Alabama 

are relatively abundant. Fossil flora are the most 

abundant, but ·zones of marine invertebrates also 

are found. Butts ( 1926) reported at least four fossiliferous horizons (presumably excluding fossil 

flora associated with many of the coal beds) in the 

Warrior field and listed the more common forms (as 

identified by G. H. Girty) as follows: 

Lingula carbonaria 

Schizophoria n. sp. (very common) 

Derbya crassa 

Productus coTa 

semireticulatus 

M arginifera muricata 

Spirifer rockymontanus 

llustedia mormoni 

C omposita sub til ita 

Solenopsis solenoides? 

A viculopecten hertzeri 

rectilateralis 

Deltopecten occidentalis 

M yalina swallowi 

P leuTop hoTus tropidop horus 

Schizodus aff. symmetricus 

Edmondia aff. E. gibbosa 

Leda bellistriata 
EXPLANATION 

B 

Coal bed 

r::::1 

L::J 

Sandstone 

till 

Shaly sandstone 

~ Conglomeratic sandstone 

or conglomerate 

Coal bed or member 

correlation lines 

Paleobotanical correlations of 

David White (Butts, 1927, p. 14) 

NOTE: Coal bed names in parentheses on Column 3 are those used in this report 

f~ 

INDEX MAP OF NORTH ALABAMA 

lookout Mountain 

Plateau coal field 

(N. M. Denson and 

R. K. Hose, written communication, 1960, and 

N. M. Denson in 

Coulter, 1947, 

p. 5) 

2 Northeastern part of 

Warrior coal field 

(Composite section from 

outcrops) 

3 

Blount Mountain 

Plateau coal field 

(Modified from A. M. Gibson 

in McCalley, 1891, p. 114) 

ao,tes Sandstone Member 

Umamed coalbedo 

Reid Gap coal bed 

4 Northeastern part of 

Coosa coal field 

(Rothrock, 1949, fig. 2 

and p. 27 and 28) · 

~ Hammond coal bod Br-coalbod 

} Fourth conclomet'llle 

Coal City coal bod 

Inman coal bod 

Broken Ar,.,., coal bed 5 Marion coal bod central part Of 

> Bibby coal zone Warrior. coal field 

(Compos1te sect1on: 

Brown coal bod lower 2,900 feet 

eam coal bed from core of 

H~bolham coal bed Southern Nat Gas 

Fotrview coal bod Phelan Sheppard 

-coal bod 1 well; upper part 

,u~fl:r"'" from outcrops) 

Lower Chapman coal bod 

Unnamed coal bod 

Unnamed coal bod 

Umamed coal bod 

Pinetandstanemomber 

of Pottsville 

I 

I 

I 

I 

I 

I 

/I 

~/ Blue c{eek Basin 

Warrior coal field / 

7 

Southwestern part of 

Cahaba coal field 

(Butts, 1940) 

_, Maylene coal bod 

•r Ma~ coal bod 

8 Stein coal bod Southwestern part of 

/ 

I 

I 

'/ 

/ 

/ 

/ 

Upper 0opooc1 coal bod Coosa coal field 

Lower Dopood coal bod (Butts, 1927) 

eatva..,a>albed 

Thif. unnamed coal bed 

(Modified from Semmes,/ 

1929, fig. 36) / ' ~Strap! Ridp coal bod StraistttRidaetandstonemomber / 

' / 

/ 

/ 

,/ 

/ 

/ 

lue Creek coat bed / 

'1---------t·•··•· 

Wolf Ridae coal bed Wolf Ridae tandstone member 

Howard coal bod 

Nivens coal bed 

Clowa>al bod 

Pinetandstonemomber 

Cumingham coal bed 

Shades sandstone member 

FIGURE 6.-Columnar sections showing position of coal beds and sandstone members of the Pottsville formation in Alabama (from Culbertson, 1964). 

........ 

~ 

~ 

1-3 

::r: 

t:=j 

a:: 

1-1 

00 

00 

1-1 

00 

00 

1-1 

""d 

""d 

1-1 

> z 

> z 

t1 

""d 

t:=j 

z 

z 

00 

~ 

t-t 

<: 

> z 

1-1 

> z 

00 

~ 

00 

1-3 

t_:l:j 

a:: 

00 

1-1 

z 

1-3 

::r: 

t:=j 

q 

z 

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t:=j 

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t:=j 

00 
PENNSYLVANIAN STRATIGRAPHY OF ALABAMA 127 

Y oldia oweni 

Anthracomya (Naiadites) elongata 

E stheria·· dawsoni 

Butts (1926) noted that except for the last two 

fossils, most of the species seem to range through 

the full thickness of the Pennsylvanian sequence, 

although they are not restricted to the Pennsylvanian elsewhere in the United States. 

Metzger (1965, p. 13) listed the following forms 

from an exposure in the Warrior field: 

Stereostylus sp. 

F enestrellina 

Lingula carbonaria Swallow 

Orbiculoidea capuliformis (McChesney) 

Chonetes choteauensis Mather 

Desmoinesia nana (Meek and Worthen) 

Dictyoclostus sp. 

Juresania ovalis Dunbar and Condra 

Linoproductus insinuatus? ( Girty) 

Schizophoria oklahomae Dunbar and Condra 

resupinoides (Co~) 

sp. 

Spirifer occidentalis Girty 

Wellerella osagensis (Swallow) 

Dentalium sp. 

Plagiog~ypta sp. 

Bellerophon crassus Meek and Worthen 

Euphemites carbonarius (Cox) 

Phymatopleura nodosus (Girty) 

Pseudozygopleura ro-thi Knight 

Straparolus (Amphis capha) reedsi Knight 

Trepospira depressa Cox 

W orthenia sp. 

Gastrioceras sp. 

Liroceras liratum ( Girty) 

Pseudorthoceras sp. 

Asta,rtella newberryi Meek 

A viculopinna sp. 

Cypricardinia carbonaria Meek 

Dunbar ella knig hti Newell 

Edmondia gibbosa (McCoy) ? 

Nucula anadontoides Meek 

sub1·otunda Girty 

Nuculana meekana (Mark) 

s.p. 

Parallelodon tenuistriatus (Meek and Worthen) 

Pteria sp. 

Schizodus affinis Herrick 

cuneatus? Meek 

Paladin sp. 

Crinoid stems 

Thuroholia sp. 

Fish teeth, undeterntined 

Butts (1926) listed fossil flora as Lepidodendron 

sp., Lepidodendron obovotum, sigillaria 1namilloris 

calamites suckowii, N europteris smithii, Pecopteris 

buttsii, and Alethopteris lonchitica. 

McKee ( 1975) studied Pennsylvanian sedimen~ 

tary rock-fossil relationships in part of the Warrior field. Several unpublished studies by major oil 

com'Panies reportedly have been made of Pennsylvanian palynology in the Warrior field. Upshaw 

(1967) recognized more than 90 species of palynomorphs in the Pennsylvanian sedimentary rocks 

of the Warrior field and found species of Lycospora 

and Densosporites to be numerically dominant in 

most samples. In addition, he pr<>vided a partial list 

of forms from several stratigraphic positions within 

the Pottsville sequence (table 1). 

TABLE 1.-A list of selected taxa from Pennsylvanian 

strata of the Warrior basin, Alabama 

[From Upshaw, 1967] 

Taxa 

Knoxisporites dissidius Neves ----------- Proprisporites laevigatus Neves --------- Trinidulus diamphidios Felix and Paden __ Tricidarisporites fasciculatus (Love) 

Sullivan and Marshall ---------------- Convolutispora florida Hoffmeister, 

Staplin and Malloy ------------------- Reinschospora speciosa (Loose) Schopf, 

Wilson and Bentall -------------------

Bellispores nitidus (Horst) Sullivan -----

Densosporites irregularis Hacquebard 

and Barss ---------------------------- Crassispora kosankei ( Potonio and 

Kremp) Bhardwaj -------------------- Knoxisporites triradiatus Hoffmeister, 

Staplin and Malloy ------------------- Knoxisporites stephanephorus Love ------ Lycospora uber (Hoffmeister, Staplin 

and Malloy) Staplin ------------------ Lycospora noctuina Butterworth and 

Williams ----------------------------- Savitrisporites nux (Butterworth and 

Williams) Sullivan ------------------- Florinites visendus (Ibrahim) Schopf, 

Wilson and Bentall ------------------- Wilsonites sp. (100-160 microns) --------

Cirratriradites saturni (Ibrahim) 

Schopf, Wilson, and Bentall ----------- Tantillus triquetrus Felix and Burbridge __ 

Ahrensisporites querickei (Horst) 

Potonie and Kremp ------------------- Cristatisporites indignabundus (Loose) 

Potonie and Kremp -------------------

Schulzospora rara Kosanke --------------

Camptotriletes superbus Neves -----------

Discernisporites irregularis Neves --------

Reinschospora triangularis Kosanke ------

Apiculatisporis variocorneus Sullivan ___ _ 

Laevigatosporites ovalis Kosanke ---------

Dictyotriletes bireticulatus Ibrahim ------

Sample locality 1 

(1) (2) (3) 

X 

X 

X 

X 

X X 

X X 

X X 

X X 

X X 

X X 

X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X 

X X 

X X 

X 

X 

1 ( 1) Below the Black Creek coal including some units assigned to 

the Parkwood Formation by Culbertson (1968); (2) Black Creek coal 

to Brookwood coal; and (8) above the Brookwood coal. 
I28 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

SUBINTERVAL A1 

Rocks included in subinterval A1 are those of the 

upper part of the Parkwood Formation and those of 

the lower part of the Pottsville Formation. The 

upper boundary of subinterval A1 is considered by 

Wanless (1975) to be at the base of the Black Creek 

coal group or the equivalent Harkness coal bed. 

Culbertson (in Wanless, 1975, p. 29) gives reasons 

why subinterval A1 is equivalent to floral zones 4 

and 5. A·ocording to Culbertson (in Wan1ess, 1975, 

p. 29), some workers have mistakenly assumed that 

the lower part of the Pottsville Formation, as defined by White (according to Butts, 1927), below 

the Black Creek coal group or the equivalent Harkness coal bed, includes o_nly floral zone 4. No wellestablished floral-zone fossils mark the top or the 

base of subinterval A1 (Wanless, 1975). Wanless 

has discussed distribution and thickness of strata 

in subinterval A1, the northern extent of which may 

have been in the general vicinity of the present Tennessee River. 

Sedimentary rocks of subinterval A1 are considered . 

to occur in all the coal fields in Alabama and may be 

represented by the Erin Shale (Wanless, 1975) 

within the metamorphic Talladega Series. Subinterval A1 strata are absent on the Plateau remnants in 

northeastern Alabama but are present south of the 

Tennessee River. Thomas (1972) has measured approximately 44 m of Parkwood sediment at Isbell 

quarry in Franklin County, northwest Alabama, but 

the thickness of Parkwood strata here that can be 

assigned to subinterval A1 is unknown. From northern Alabama, subinterval A1 sedimentary rocks 

thicken southeastward to a maximum of more than 

510 m near Birmingham. Subinterval A1 sedimentary rocks range in thickness from 900 m to more 

than 1,500 m in the Cahaba coal field ; in the Coosa 

coal field, they are about 1,500 m thick. In Sumter 

County in the southern part of the Warrior field, a 

thickness of 489 m has been reported (Wanless, 

1975). Metzger (1965, p. 10) called attention to 

thinning of the rocks in subinterval A1 and suggested that inasmuch as the area of thinning is 

directly in line with the later formed Blountsville 

or Sequatchie anticline, the sedimentation might 

have been controlled by local tectonic activity even 

in early Pottsville time. 

Subinterval A1 strata consist of mudstone, claystone, siltstone, sandstone, conglomerate, and thin 

coal beds. Sandstone generally is more abundant 

than the other types of sedimentary rocks in northcentral Alabama and is generally less abundant in 

basins that include thousands of feet of strata 

(Wanless, 1975). The Parkwood Formation includes 

both orthoquartzitic sandstone and graywacke sandstone as well as a considerable volume of gray 

slightly silty shale. Rocks herein referred to as belonging to subinterval A1 have often been referred 

to informally as "the lower unproductive zone" in 

reference to the relatively few thin coal beds within 

the sequence. 

Ferm (Ferm and Ehrlich, 1967), in discussing the 

general petrology of Pennsylvanian sedimentary 

rock in Alabama, classified most of the coarser sediments as lower rank graywacke and reported varying proportions of strained and sheared (metamorphic) quartz, sodic feldspar, a great variety of lowgrade micaceous metamorphic rock fragments, and 

some detrital volcanic fragments. Heavy minerals 

include staurolite, kyanite, epidote, garnet, muscovite, chlorite, tourmaline, and zircon. Studies by 

Ferm (Ferm and Ehrlich, 1967) also show that components of finer grained sedimentary rocks are similar to those of the coarser grained rocks but include 

a considerable amount of illite and lesser kaolinite. 

Ferm (Ferm and Ehrlich, 1967) also stated that 

quartz content of the low-rank graywackes diminishes from north to south. 

The number of coal beds in subinterval A1 is 

greatest in the southern Plateau field (Blount Mountain) and in the Coosa and Cahaba fields. These fields 

contain as many as 15 coal beds, but maximum cumulative thickness is only 4.5 to 5.8 m (Wanless, 

1975). The number of beds decreases to the west 

and northwest. Wanless (1975) pointed out that the 

average thickness of coal beds in Alabama is remarkedly less than the average thickness of similarage sediments in the Pocahontas field of Virginia, 

although the environments of coal deposition were 

similar. Culbertson (1964) showed stratigraphic 

position of the coal bed~ and sandstone members in 

the lower Pottsville (fig. 1). 

Wanless ( 1975) suggested an easterly or southeasterly sources for subinterval A1 sediments, citing 

pattern of grain-size distribution and crossbedding 

(Schlee, 1963, p. 1448). Metz.ger (1965) interpreted 

crossbedding data to indicate that the predominant 

flow of s·edimentary detritus in theW arrior field was 

from northeast to southwest, that flow direction in 

the northeastern part of the Warrior field was to the 

southwest, and that flow direction in the western 

part of the field was to· the west. Wanless (1975) 

gave the opinion that the moderately coarse grained 

rock in north-central Alabama suggests there was a 
PENNSYLVANIAN STRATIGRAPHY OF ALABAMA I29 

nearby land area, prob~bly east or southeast of 

present outcrops, and that .the pattern of grain size 

distribution is consistent with an easterly source for 

sediments, as inferred by cross-bedding measure .. 

ments (Schlee, 1963, p. 1448). Ehrlich (1965; Davis 

and Ehrlich, 197 4, p. 177) postulated a southern 

source on the basis of distribution of unstable minerals, an apparent increase from south to north in 

relative percentage of quartz in the low-rank graywackes, and a southward thickening and increasing 

proportion of sandstone in the sedimentary sequence. Ferm (Ferm and Ehrlich, 1967) observed 

that this source area may have extended into the 

Ouachita orogenic belt. Hobday (1974, p. 223) on 

the basis of geometry of basal Pottsville beach and 

barrier-island facies, concluded that two distinct 

sources may have existed in the lower Pennsylvanian clastic rocks in northern Alabama, one in the 

northeast and the other to the south. 

Individual beds or lithologic units in the Pottsville 

sequence are laterally discontinuous, and, at present, data are insufficient to delineate accurately the 

lateral distribution of even major lithologic units. 

Many workers now accept, as a working hypothesis, 

the concept of prograding delta systems to explain 

the variations in lithology and distribution patterns. 

Ferm and Ehrlich (1967) suggested that lower 

Pottsville and Parkwood orthoquartzite's can be attributed to a beach-barrier system, which separated 

deltaic from offshore facies and became much 

broader as progradation proceeded from the "geosynclne" on to the "shelf"; they further suggested 

that some of the Parkwood graywacke sandstone 

apparently represents local overriding of the barrier 

system by rapidly prograding deltaic deposits, 

whereas other Parkwood graywac~es p·robably represent sediment that was transported through barrier passes to accumulate in offshore bars below the 

zone of intensive wave action. 

PLATEAU FIELD 

Insufficient work has been done to define boundaries of subintervals AH A2 and interval B in the 

Plateau field; Wanless (197·5) noted, however, that 

subinterval A1 strata are abs·ent in the Plateau field 

north of the Tennessee River but appear in the field 

south of the river. Because of this lack of stratigraphic detail, the description of the Plateau field in 

this paper is given here under dis·cus.sion of subinterval A1 strata. 

Strata on Blount Mountain in the Plateau field 

consists of four principal conglomerate members: 

the First, Second, Third, and Fourth Conglomerates 

(Gibson, 1891, 1893). Although Gibson has provided considerable detail on strata of the Plateau 

field, his two reports, as Culber.ts·on ( 1964) observed, are often in conflict or are inconsistent with 

regard to thickness of strata. In brief, the stratigraphic sequence in the Plateau field may be described as, follows: .the First conglomerate, correlated by Butts ( 1910) as the equivalent of the 

Boyles Sandstone Memher in the W arrio.r field, lies 

at the base of the Pottsville sequence and is estimated to be as much as 30 m thick. The First Conglomerate is overlain by a shale, sandstone, and coal 

sequence estimated to be about 70 m thick. This 

variable sequence is overlain by the Second Conglomerate, estimated to be as much as 45 m thick. 

stone, and coal beds, reported by Gibson to be either 

The Second Conglomerate is overlain by shale, sand240 m thick and containing 11 coal beds (Gibson, 

1891, p. 114) or 728 m thick and containing 25 coal 

beds (1893, p. 29). This coal-bearing sequenc·e is 

overlain by the Third Conglomerate, which may be 

as much as 45 m thick. The Third Conglomerate is 

overlain .by shale, sandstone, and coal beds reported 

by Gibson to be either 67 m thick and containing 4 

coal beds (Gibson, 1891, p. 114), or 342m thick and 

containing 15 coal beds (Gibson, 1891, p. 29). This 

sequence is overlain by the Fourth Conglomerate, 

which was reported by Gibson ( 1893, p. 22) to consist of an upper section 3 to· 4.5 m thick, a second 

section a:bout 12 m thiok, and a lower section about 

30 ·m thick. The Fourth Conglom·erate is. reported to 

be about 15m beneath the highest strata exposed on 

Blount Mountain. Gibson ( 1893, p. 29) reported 

this strata in T. 12 S., R. 3 E., to consist of shale, 

t.hin- and thick..;bedded sandstone, clay, ironstone, 

underclay, and coal beds. 

Many of the coal beds are thin and discontinuous 

on Blount Mountain. The Howard and Caskie coal 

beds are between the Firs,t and Second Conglomerates. The Swansea, Washington, and several unnamed coal beds lie between the Second and Third 

Conglomerates. According to Culbertson (1964), the 

Swansea is also know as the "Inland" and "Jagger" 

coal beds. The Swansea is reported to be as much 

as 1m thick and has been mined along the northwest edge of Blount Mountain (Culbertson, 1964). 

The Altoona or "Underwood" and Woodward coal 

· beds are between the Tihrd and Fourth Conglomerates, the Woodward being immed.iately underneath 

the Fourth Conglomerate. The Altoona is about 

76 em thick and has been mined on the surface as 
I30 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

well as underground. The Bynum coal bed directly 

overlies the Fourth Conglomerate in a small area on 

Blount Mountain in T. 12 S., R. 3 W., but is generally 

too thin to be mined independently (Culbertson, 

1964, p. 315). 

The section on Lookout Mountain in the Plateau 

field, as described by Culbertson (1964), includes 

the Lower Conglomerate, overlain by a thin sequence 

(about 30m thick) of shale, sandstone, and coal 

beds, including the Underwood coal bed and Upper 

Cliff coal beds. These units are overlain by the 

Upper Conglomerate, which is overlain by a series 

of shale, sandstone, and coal beds, including the 

Sewanee coal bed and the Tatum coal bed. Culbertson (1964) noted that a coal bed termed the Castle 

Rock (Cliff) coal bed underlies the Lower Conglomerate. 

WARRIOR FIELD 

The Boyles Sandstone Member is a basa1l conglomeratic orthoquartzite sandstone in the Warrior field; 

it ranges from 60 to 213 m in thickness, as indicated 

from oil and gas test-hole logs. This unit is interbedded with varying amounts of gray shale, thinbedded micaceous sands.tone, and locally, one or 

more thin coal beds (Culbertson, 1964). The lower 

part of the Boyles. Sandstone Member is generally 

conglomeratic and the upper part, nonconglomeratic, 

although conglomeratic lenses are reported in the 

upper part in a few localities. The Boyles forms 

steep bluffs along the northern edge of the Warrior 

field, prominent ridges along the southeastern edge 

of the field, and the ridges bordering the· Sequatchee 

Valley. The unit is thinnest along the southeast 

margin of the Warrior field and reportedly thickens 

westward and southwestward in the subsurfac-e. 

The Boyles Sandstone Member usually includes a predom-inantly shaly unit, which has been used by some 

workers to divide the Boyles into two· unnamed 

sandstone units. According to Culbertson (1964), 

the Boyles can be divided into a third sandstone unit 

at a few places in the Warrior field, such as along 

the southeast edge of the· Blue Creek basin. In severai other places in the Warrior field, Culbertson 

(1964) observed that the intervening shaly unit 

either has graded to sandstone, has been cut out 

by the overlying sandstone bed, or is insignificantly 

thin. The upper boundary of the Boyles Sandstone 

Member in the Warr.ior field .is indistinct at some 

localities where the orthoquartzite beds grade upward to dark micaceous sandstone beds. 

In the Blue Creek basin of the Warrior field, approximately 600 m of strata beneath the Black 

Creek coal group includes several coal beds. A 

coal bed locally called the Polecat in Marion and 

Winston Counties may be equivalent to the Sapp 

(Culbertson, 1964). The J, K, L, and M beds are 

reported to be persistent throughout the basin. The 

J bed is reported to be about 90 m below the Black 

Creek coal bed and to have an average thickness 

across the bas.in of 76 em (Culbertson, 1964, p. 

B21). 

CAHABA FIELD 

Subinterval A1 in the Cahaba field includes the 

Shades Sandstone Member at the bottom and extends upwa~d to· the botto·m of the Harkness coal 

bed. The Shades Sandstone Member is considered 

the equivalent of the Boyles Sandstone Member of 

the Warrior field and is generally overlain by a shale 

sequence, which separates it from the Pine Sandstone Member. Culberton (1964) correlated the Pine 

Sandstone Member with sandstone sequences in the 

upper part of the Boyles Sandstone Member of the 

Warrior field. Two sandstone units, the Chestnut 

Sandstone Member and the Rocky Ridge Sandstone 

Member and several coal beds occur in the interval 

between the Pine Sandstone Member and the upper 

boundary (base of Harkness coal bed) of subinterval A1 in the Cahaba field, (Culbertson, 1964, p. 

B36). The Chestnut ranges from 30 to 60 m in 

thickness and is a quartzose sandstone that makes 

a prominent ridge along the entire Cahaba field 

(Culbertson, 1964). The Chestnut is separated from 

the underlying Pine Sands.tone Member by 150 to 

240 m of strata, which is mostly shale and which 

contains the Gould coal bed (Butts, 1927, p. 14; 

1940, p. 11). The Rocky Ridge Sandstone Member is 

a thick-bedded conglomeratic quartzose sandstone 

about 15 to 30 m thick that J.ies about 730 m above 

the Chestnut Sandstone Member in the interval between the Buck and Pump coal beds (Culbertson, 

1964, p. B36) . 

COOSA FIELD 

The Shades and Pine Sandstone Members constitute the lower part of the Pennsylvanian sequence 

in the Coosa field. The Shades is a sparsely conglomeratic quartzose sandstone about 60 m thick 

separated from the Pine Sandstone Member by about 

60 to 90 m of shale and fine-grained sandstone (Rothrock, 1949). About 1,450 m of strata overlies the 

Pine, and no specific upper boundary of subinterval 

A1 sediments has been identified. 
PENNSYLVANIAN STRATIGRAPHY OF ALABAMA I31 

SUBINTERVAL Az 

In Alabama, the middle part o.f the Pottsville 

Formation is considered to be subinterval A2. In 

the Plateau field, only the lower par:t of subinterval 

A2 is recognized, although the lower boundary in 

this field is ill defined. Subinterval A2 in Alabama 

may include flo·ral zone 5 fossils in its lower part 

near the Black Greek coal group (Wanless, 1975), 

as inferred 'by occurrence of floral zone 5 near the 

Battle Creek coal bed in the Gizzard Formation in 

Tennessee, a unit apparently corr·elative with Alabama subinterval A2 sed:imentary rocks. Wanless 

( 1975) stated that floral zone 6, characterized by 

M areopte1·is pygmaea and N europteris tennesseana 

was reported above the Mary Lee coal in the Warrior field by White (according to Butts, 1927, p. 

15). In addition, the Wadsworth coal in the Cahaba 

field (Butts, 1927) has yielded thi.s flora. The Erin 

Shale (phyllite), in the Talladega. metamorphic 

ser.ies in Clay County may include strata of subinterval A2, according to Wanless (1975). Wanless 

( 1975) observed that in the Alabama. coal basins, 

the sandstones of subinterval A2 are less easily distinguished from those overlying them than they are 

in Tennessee and northward. 

The upper part o.f the Pottsville Formation in 

Alabama is mostly strata of subinterval A2 and is 

characterized by sandstone, siltstone, mudstone, 

underclay, co·al beds, shale, and ~ones of marine and 

brackish-water fossils. Culbertson (1964) described 

the rocks as a somewhat rythmical sequence; however, Wanless sugges·ted that although a semblance 

of cyclic sedimentation may appear in a given stratigraphic section, such cycles are only apparent when 

the patterns o.f lateral and vertical distribution of 

the sedimentary rocks are studied. Shale is the predominant rock type, ranging from medium. gray 

and silty to grayish black and carbonaceous. Shale 

may grade vertically and laterally to· argillaceous 

gray siltstone and gray to tan very fine grained 

sandstone. Ripple marks are commonly preserved 

in the siltstone and fine-grained sandstone. Interbeds of shale, siltstone, and sandstone are common. 

Siderite or ankerite concretions, usually less than 7 

em in maximum diameter are common in the shale. 

Sider:ite may occur as a lens as much as 30 em thick 

and more than a meter in diameter, and at some 

localities, layers of siderite less than 2.5 em thick 

are interbedded with the shale (Culbertson, 1964). 

Sandstones frequently have sedimentary structures 

(crossbedding, ripple and current marks) and are 

massive to thick bedded, fine to coarse grained, and 

well indurated. Thickness o.f the sandstones varies 

laterally and is as much as 30 m. Culbertson 

(1964) pointed out that the sandstones differ from 

the orthoquartzite sandstone beds of the Boyles 

Sandstone Mem·ber (within subinterval A1) in that 

they are darker gray and contain mica, clay, and 

carbonaceous material, including coalified plant 

fragments. 

WARRIOR FIELD 

Subinterv·al A2 strata in the Warrior field includes· 

the Black Creek coal bed at the ·bottom and the 

Brookwood coal group at the top. As noted earlier, 

the thin succession of rocks capping Plateau regions 

north of the Tennessee River (northern part of the 

Plateau field in northeastern Alabama) consists 

I largely or entirely of the lower part of subinterval 

A2 (Wanless, 1975). From this outcrop area, these 

strata thicken southward. From west-central 

Walker Gounty to northe·m Tuscaloosa County, the 

sequence thickens. in a distance of 30 km from 153 

m to 646 m (Wanless, 1975). W·anle:ss noted that 

the sparse well data in Pickens .and Sumter Counties 

indicate that south of the belt of rapid thickness 

change, subinterval A2 strata appear to be uniform 

in .thickness. 

The more prominent sandstone beds in subinterval 

A2 rocks in the Warrior field have been named as 

sandstone members and include, from oldest to 

youngest, the Bremen, Lick Creek, Camp Branch, 

and Raz-burg. Many linear channel-fill s·andstones 

occur in the Pottsville, and Culbertson ( 1964) has 

provided some general information on distribution. 

of one of the channels within the Pratt group. New 

stratigraphic and lithologic data are being rapidly 

accumulated from the Warrior field through ongoing 

coal exploration and coal m:ining and through exploration for gas and petroleum. In the near future 

it may be possible to begin .studies of the distribu-. 

tion of some o.f the lithologic units within the 

Pottsville. 

Subinterval A2 rocks in the Warrior field include 

the major coal beds of that field. These beds are 

·grouped into seven coal groups, which are, from 

oldest to youngest: Black Creek, Mary Lee, Pratt, 

Cobb, Gwin, Utley and Brookwood. Of the more 

than 25 coal beds within these groups, not all are 

persistent or of sufficient average thickness to be 

mined. Bituminous coal beds and underclays are 

regionally more persistent in the warrior field than 

are most o.f the other lithologic units. Clay, s.ilt1 stone, and siderite partings in the ·coal range from 
I32 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

a few centimeters to as much as 3 m in thickness 

(Culbertson, 1964). The individual coal beds may 

pinch out, ·Coalesce, or split. The coal underclay 

generally lacks bedding features, is light gray, and 

frequently shows root marks (stigmaria) (Culbertson, 1964). 

CAHABA F'IELD 

Wanless (1975) places subinterval A2 strata in the 

Cahaba field from the base of the Harkness coal bed 

to the base of the Y eshic coal bed. Pennsylvanian 

strata reach a maximiUm thickness of 2, 7 40 m and 

are described by Culbertson (1964) as consisting of 

a lower part (Shades Sandstone Me·mber and Pine 

Sandstone Member previously mentioned as. belonging to subinterval A1 strata), a middle part consisting of shale, sandstone, and .commercial coal beds, 

and an upper part .consisting of thick conglomerate 

beds and commercial coal beds. Culbertson (1964) 

defined the middle part as lying between the Pine 

Sandstone Membe·r and the Straven conglomerate 

(fig. 6, locality 7). 

A unique conglomerate memher, the Straven, 

occurs in the upper part of subinterval A2 sedimentary rocks in the Cahaba field. The Straven Conglomerate· Mem,ber is characterized by large pebble:S 

and .cobbles as much as 20.3 em in diamete·r and a 

higher portion of pebbles to matrix. Culbertson 

(1964) gave thickness of this conglomerate as 9 to 

32 m in the Montevallo and Maylene basins of the 

Cahaba field. Butts (1910, .p. 10) indicated that the 

Straven thins to the north, and suggested (Butts, 

l940, p. 13) that the pebbles were derived from 

erosion of the· W axahak:hee Slate, Brewer Phyllite, 

Wash Creek Slate, W·eisner Quartzite·, and Copper 

Ridge Dolomite, exposures, of which are a few kilometers southeast of the Cahaba field. Culbertson 

(1964) reported that more than 35 coal beds occur 

in the 1,950 m-thick "productive" part of the sequence, which he defines as lying above the Gould 

coal bed. Of these, more than 22 beds are between 

the Harkness and Yeshic coal heds. Coal beds included in this interval are, in order of decreasing 

age: Wadsworth, Big Bone, Pump, Buck, Youngblood, Clark, Gholson, Quarry, Smithshop, Lower 

Thomp:son, Up·per Thompson (Upper and Lower 

Tihompson separated by Straven Conglom·erate), 

and Helena. 

NORTHEASTERN COOSA FJoELD 

Wanless ( 197·5) did not specify the lower boundary of subinterval Az strata in the Coosa field;. he 

designated the top of subinterval Az as the bottom 

of the Brewer coal bed. A specific upper boundary 

of the "middle barren part" was not suggested by 

Culbertson (1964). 

In northeastern Coosa field, Culbertson (1964), 

p. B45) described the strata as being divisible into 

three parts-a lower part consisting of the Shades 

and Pine Sandstone Members, a middle barren part, 

and an upper coal-bearing part. Culbertson's 

"middle barren part" is not the exact equivalent of 

subinterval Az strata as defined by Wanless ( 1975). 

In the Wattsville basin of northeastern Coosa 

County, Rothrock ( 1949) estimated a total .thickness of Pennsylvanian strata of about 1,650 m. Here, 

Rothrock (1949) reported Pennsylvanian strata 

above the· Pine Sandstone Member as being 1,440 

m thick, including in the lower 840 m, lenticular 

beds of sandstone, siltstone, and ·claystone that 

locally contain three nonpersistent coal beds generally less than 30 em thick. Overlying this sequence 

(Rothrock, 1949, p. 23) is 600 m of coal-bearing 

strata which consists chiefly of fine- to medium.-

grain sandstone, carbonaceous claystone, and siltstone inter·bedded with coal beds. 

Culbertson (1964) recognized 14 named beds of 

bituminous coal in northeastern Coosa County (fig. 

6, locality 4), which vary in areal extent. Within 

this sequence of coal-bearing strata, about 60 m 

above the Coal City coal bed, is a 45-m-thick .sandstone bed containing scatter·ed quartz pebbles. This 

is the Fourth or upper conglomerate of Gibson 

( 1895, p. 79). The Brewer coal bed, the botto.m of 

which .marks the top of subinterval A2 strata, lies 

above the Fourth Conglomerate. 

SOUTHWESTERN COOSA FIELD 

Butts (1927) r·eported Pennsylvanian strata in 

the Yellow Leaf Basin of southwestern Coosa field 

as 2,220 m thick, of which 1, 7 40 m -consists of strata. 

overlying the Pine Sandstone Member. Of this 1,740 

m, the lower 1,140 m is composed of shale and sandstone and contains two main sands·tone membersthe Wolf Ridge and .Straight Ridge-and seven coal 

beds. The remaining 600 m (an undetermined thickness of which probably includes interval B strata) 

consists of shale and thin sandstone. The Wolf Ridge 

Sandstone Member is about 360 m above the Pine 

Sandstone Member and is 15 to 30 m thick. The· 

Straight Ridge Sandstone Member is about 244 m 

above the Wolf Ridge Sandstone Member. Of the 

seven coal beds, most are thin. Prouty (1912) measured a section in Yellow Leaf Basin of southwest-
PENNSYLVANIAN STRATIGRAPHY OF ALABAMA I33 

ern Coosa basin and gave the following data on the 

coal beds observed above the second conglomerate 

(Pine Sandstone): Glow, 15 to 76 em; Double Ridge, 

7 to 40 em ; Straight Ridge, 20 to 60 em; Martin, 15 

to 365 em; Marker, 0 to 15 em; and unnamed coal 

bed, 7 to 30 em. In addition, Butts ( 1927, p. 19) 

reported a coal bed named the Cunningham as 2m 

thick. Culbertson ( 1964) is o.f the opinion that this 

thickness is confined to a very small area. 

INTERVAL B 

Wanless (1975) noted that rocks of Interval B 

are characterized by extraordinary lithologic com.-

plexity in the Appalachian region and that the sandstones within the interval are generally less conglomeratic, finer grained, and less quartzose. than 

those of Interval A. Interval B strata have not been 

adequately defined in the Warrior, Coosa, and 

Chahaba basins, although Wanless (1975), p. 35) 

suggested some lower boundaries of rocks in these 

regions. Interval B is considered to· include floral 

zones 7 and 8 of Read and Mamay (1964). Zone 

7 is characterized by M egalopteris spp., which are 

found in the basal part of Interval B. Zone 8 is 

charaterized by N eu'ropteris tenuifolia (Wanless, 

1975). 

During Interval B time, according to· Wanless 

(1975, p. 39), the Appalachian and Black Warrior 

basins were bordered on the southeast by tectonically deformed highlands that probably extended 

from P.hiladelphia, Pa., to Georgia and were the 

probable principal source of the detrital sediments. 

Wanless (1975, p. 40) suggested that, in general, 

Interval B in the Appalachian area consists largely 

of fluviatile and deltaic deposits that accumulated 

on a surface of very low relief. In Alabama, however, coarser detrital sediment appears to have been 

derived from nearby elevated land areas south of the 

Cahaba and Coosa fields. The southern Cahaba field 

is among the few areas in the Appalachians that 

show much conglomerate in upper Pennsylvanian 

strata (Wanless, 1975, p. 40). This conglomerate 

was described by Butts ( 1940) . 

WARRIOR FIELD 

In the Warrior field, Wanless (1975) considers 

all Pennsylvanian rocks above the Brookwood coal 

group to be within Interval B and has tentatively 

traced these rocks in western Alabama and Mississippi on the basis of electric logs. These strata occur 

only in the subsurface, as the Brookwood coal group 

is the highest outcropping unit in the Warrior field. 

Interval B strata in the Warrior field have not been 

studied sufficiently to· permit their classification. 

Upshaw (1967, p. 18) noted that to the west in the 

subsurface of Mississippi, beneath the Cretaceous 

overlap, beds of Kanawha age are included with the 

Pottsville Formation. The upper boundary of Interval B in the Warrior field is considered to be the 

unconformable Cretaceous contact. 

CAHABA FIELD 

White (quoted by Butts, 1927, p. 14) suggested a 

boundary between middle and upper Pottsville 

strata in the Cahaba field, and Wanless ( 1975) 

referred to the rocks containing White's upper 

Pottsville as Interval B. In this field, Wanless 

( 1975) considers all Pennsylvanian strata, including 

and younger than. the Yeshic coal, to· be within 

Interval B (Wanless, 1975, p. 35). The upper 

boundary of Interval B in the Cahaba field is the 

contact with unconformably overlying Cretaceous 

rocks (Wanless, 1975). 

Butts ( 1940) showed approximately 725 m of 

sandstone and shale interbedded with coal beds overlying the Y eshic coal in the Cahaba field. Culbertson (1964, p. B-37) called attention to the many 

test holes drilled during 1957 in the Montevallo and · 

Maylene bas,ins of the Cahaba field and estimated 

that 10 to 20 percent of the upper Pottsville sequence .consists of fine-grained, thin-bedded micaceous sandstone, shale, underclay, and about 20 coal 

beds. In addition, Culbertson (1964, p. B37) estimated that more than 50 percent of the upper Pottsville sequence consists of fine- to coarse-grained 

sandstone :in beds as much as 30m thick, a remaining 25 percent consisting o.f conglomerate and conglomeratic sandstone. Several coal beds, including 

the Y eshic, Montevallo, and Maylene, and some thin 

coal beds occur in the interval of the Cahaba field 

strata ·considered by Wanless to be Interval B. Culbertson (1964) has provided a general description 

of the stratigraphy of this interval. The Montevallo 

coal bed is 115 to 131 m above the Yeshic bed (the 

bottom of which is considered to. be the lower boundary of Interval B) in the Maylene, Dry Creek, and 

Montevallo basins. Between the Montevallo and Maylene coal beds in the ·Maylene basin is a sequence 

of sandstone, conglomerate, and shale that averages 

about 390 m in thickness and in places contains as 

many as 15 coal beds. Wanless ( 1975, p. 39) stated 

that nearly twice this number of coal beds could be 

shown in southern Cahaba field if all the seperate 

benches are considered. Many of these coal beds are 
I34 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

reported to be 35 em thick and locally as much as 

1.2 m thick. Butts (1927, fig. 5) named seven beds 

in the interval between the Montevallo and Maylene 

coal beds, including, in ascending order, the Airshaft, Dogwood (upper and lower), Stein, Luke, 

Wooten, and Lovelady. The Maylene coal consists of 

an upper and lower bed, the lower bed being 2 to 

12 m below the upper. A coal bed called the Polecat 

is about 60 to 75 m above the Maylene and is the 

highest coal bed in the Pennsylvanian s.equence in 

the Cahaba field (Culbertson, 1964). 

COOSA FIELD 

In the Coosa field, Pennsylvanian strata including the Brewer coal bed and rocks above it, is considered by Wanless (1975, p. 35) as Interval B. The 

upper boundary of the interval is considered to be 

the unconformable contact between the overlying 

Cretaceous sedimentary rocks. Culbertson (1964) 

termed the upper 600 m of the Pennsylvanian sequen·ce in northeastern Coosa field as the "upper 

coal bearing part," near the top of which is the 

Brewer coal. The thickness of Interval B strata in 

the northeastern Coosa field, as inferred from the 

work of Rothrock ( 1949, p. 3) may be slightly more 

than 30 m, although Wanless (1975, p. 38) has interpreted the thick sequence of strata in the Wattsville basin in northeastern Coosa field as being entirely in Interval A. Within the Interval B sequence 

in northeastern Coosa County is the Hammond coal, 

which reaches a maximum thickness of 231 em 

(Culbertson, 1964, p. B49). 

Studies suJficient to delineate the lower boundary 

of Interval B have not been made in southwestern 

Coosa County. Wanless (1975, p. 38) referred to a 

thickness of 115 m of strata in the southern part of 

the Coosa field as Interval B strata. 

COAL RESOURCES 

The Pennsylvanian-age coal in Alabama is generally high-grade banded "bright" bituminous that 

is ranked as high volatile A to low volatile. Most 

of the coal is high volatile A bituminous. Ash content generally ranges from 3 to 15 percent, and sulfur content is usually less than 2 percent (Culbertson, 1964, p. B51). Culbertson (1964, p. B53) stated 

that the rank of Alabama coals increases generally 

from northwest to southeast and suggested that the 

probable cause for this is such interacting factors 

as the variation of amount of horizontal comp-ression, oomyosition of the coal, and weight of overlying beds during maximum depth of burial of the 

coal. 

Many studies, based on field exploration programs 

have been made of Alabama coal resources. Most of 

these studies have been restricted to relatively small 

properties or to a small part of a coal field and are, 

for the most part, unpublished. Segments of the coal 

fields have been dealt with on a larger scale by the 

Geological Survey of Alabama (Daniel, 1969a, 

1969b; Daniel and Fies 1971; Neathery and others, 

1969a, 1969·b). Various studies have been made of 

coal reserves, notably those by McCalley ( 1886) , 

Warrio-r coal field; Campbell (1913, 1929), Warrior, 

Cahaba, and Coosa fields; Squire ( 1890, p. 13), 

Cahaba field; Butts (1907, p. 113·; 1911, p. 143), 

Cahaba field; Prouty (1909, p. 923), Coosa field; 

Jones (1929, p. 25), Coosa field; Rothrock (1949, p. 

88), Coosa fi·eld; Culbertson (1964) and Ward and 

Evans (1977), Warrior field. The various investigators have used a wide range of criteria in making 

their estimates of reserves, and the comparison of 

estimates is, therefore, difficult. Campbell (1929) 

estimated that the original reserves of coal in Alabama total 67,570 million short tons in beds that 

are 35 em or more thick and that are under less 

than 3,000 feet of overburden. Culbertson (1964) 

estimated that coal reserves remaining in Alabama 

total 13,753.8 million short tons in beds that are 

35 em or more thick and that are under less than 

914 m of overburden. Culbertson gave figures for the 

separate fields as follows: Warrior field, 11,904.6 

million short tons or 86 percent of the State coal; 

Cahaba field, 1,766.3 million short tons or 13 percent of the State total; Coosa field, 41.4 million short 

tons or about 0.3 percent of the State total; Plateau 

field, 41.5 million short tons or about 0.3 percent 

of the State total. Culbertson (1964) noted that 

his estimates are considerably lower than those 

made by Campbell because: ( 1) reserves were not 

calculated for large areas where data were not 

available; (2) test-hole data from the Warrior field 

indicate a westward thinning of minable coal; and 

( 3) assumptions (made by Culbertson) concerning 

thicknesses of coal away from areas of proved thickness are conservative. Ward and Evans (1977) 

have estimated total remaining reserves at 35 

billion short tons with a recoverable reserve estimate of 18.4 billion short tons. At the time of this 

writing, the Geological Survey of Alabama is preparing estimates of the total State reserves based 

on latest available coal data. 
PENNSYLVANIAN STRATIGRAPHY OF ALABAMA 135 

SELECTED REFERENCES 

Butts, Charles, 1907, The northern part of the Cahaba coal 

field, Alabama: U.S. Geol. Survey Bull. 316-a, p. 76-115. 

--- 1910, Description of the Birmingham quadrangle 

[Alabama]: U.S. Geol. Survey Geol. Atlas, Folio 175, 

24 p. 

--- 1911, The southern part of the Cahaba coal field, 

Alabama: U.S. Geol. Survey BulL 431-b, p. 89-146. 

--- 1926, Geology of Alabama-The Paleozoic rocks: 

Alabama Geol. Survey Spec. Rept. 14, p. 40-230. 

--- 1927, Description of the Bessemer and Vandiver 

quadrangles [Alabama]: U.S. Geol. Survey Geol. Atlas, 

Folio 221, 22 p. 

--- 1940, Description of the Montevallo and Columbiana 

quadrangles [Alabama]: U.S. Geol. Survey Geol. Atlas, 

Folio 226~ 20 p. 

Campbell, M. R., 1913, The coal reserves of the United 

States in The coal resources of the world: Internat. 

Geol. Cong., 12th, Toronto, 1913, v. 1, p. lxiii-lxiv; v. 2, 

p. 525-539. 

--- 1929, Coal resources of the United States: Washington, D.C., U.S. Geol. Survey press release. 

Carrington, T. J., 1967, ·Talladega Group of Alabama, in A 

field guide to Carboniferous detrital rocks in northern 

Alabama-Geol. Soc. America, Coal Div., 1967 Field 

Trip: University Ala., Alabama Geol. Soc., p. 24-27. 

Coulter, D. M., 1947, Coking coal deposits on Lookout Mountain DeKalb and Cherokee Counties, Alabama: U.S. 

Bu/ Mines Rept. Inv. 4030, 89 p. 

Cropp, F. W., 1960, Pennsylvanian spore floras from the 

Warrior basin, Mississippi and Alabama: Jour. Paleontology, v. 34, no. 2, p. 359-367. 

--- 1963, Pennsylvanian spore succession in Tennessee: 

Jour. Paleontology, v. 37, no. 4, p. 900-916. 

Culbertson, W. C., 1963, Correlation of the Parkwood Formation and the lower members of the Pottsville Formation in Alabama: U.S. Geol. Survey Prof. Paper 450-E, 

p. E47-E50. 

--- 1964, Geology and coal resources of the coal-bearing 

rocks of Alabama: U.S. Geol. Survey Bull. 1182-B, p. 

B1-B79. 

Daniel, T. W., Jr., Clarke, 0. M., Jr., and Szabo, M. W., 

1969, Mineral resources map of Winston County, Alabama: Alabama Geol. Survey Map 74, including text. 

Daniel, T. W., Jr., and Fies, M. H., 1970, Strippable coal in 

the Fabius area, Jackson County, Alabama: Alabama 

Geol. Survey Bull. 96, 97 p. 

Davis, M. W., and Ehrlich, Robert, 1974, Late Paleozoic 

crustal composition and dynamics in the southeastern 

United States, in Briggs, Garrett, ed., Carboniferous of 

the southeastern United States: Geol. Soc. America 

Spec. Paper 148, p. 171-185. 

Ehrlich, Robert, 1964, Field trip guidebook to the Pottsville 

Formation in Blount and Jefferson Counties, Alabama: 

University, Ala., Alabama Geol. Soc., 9 p. 

--- 1965, The geologic evolution of the Black Warrior 

detrital basin: Baton Rouge, La., Louisiana State Univ., 

unpub. Ph.D. dissert. . 

Ferm, J. C., and Ehrlich, Robert, 1967, Petrology and stratigraphy of the Alabama coal fields, in A field guide to 

Carboniferous detrital rocks in northern AlabamaGeoL Soc. America, Coal Div., 1967 field trip: University, Ala., Alabama Geol. Soc., p. 11-15. 

Gibson, A. M., 1891, Report on the coal measures of Blount 

County, in McCalley, Henry, Report on the coal measures 

of the plateau region of Alabama: Alabama Geol. Survey [Spec. Rept. 3], p. 114-122, 189-215. 

--- 1893, Report on the coal measures of Blount Mountain: Alabama Geol. Survey [Spec. Rept. 5], 80 p. 

--- 1895, Report upon the Coosa coal field: Montgomery, 

Ala., Alabama Geol. Survey, 1~3 p., maps. . 

Hobday, D. K., 1969, Upper Carbomferous shorehne systems 

in northern Alabama: Baton Rouge, La., Louisiana. 

State Univ., unpub. Ph.D. dissell't. 

--- 1974 Beach and barrier-island facies in the upper 

Carboniferous of northern Alabama, in Briggs, Garrett, 

·ed., Carboniferous of the ·southeastern United States: 

Geol. Soc. America Spec. Pape·r 148, p. 209-224. 

Horne, J. C., Ferm, J. C., and others, 1976, A field guide to 

Carboniferous littoral deposits in the Warrior basin: 

New Orleans, Louisiana Geol. Soc., 80 p. (Guidebook 

for field trip held in conjunction with annual AAPG/ 

SEPM Convention, New Orleans, La., May 23-26, 1976.) 

Jones, ,V. B., 1929, Summary report on the Wattsville basin 

of the Coosa coal field: Alabama Geol. Survey Circ. 6, 

48 p. 

Kidd, J. T., 1976, Configuration of the top of the Pottsville 

Formation in west-central Alabama: Alabama State Oil 

and Gas Board Map 1. 

McCalley, Henry, 1891, Report on the coal measures of the 

plateau region of Alabama: Alabama Geol. Survey 

[Spec. Rept. 3], 238 p. 

--- 1886, On the Warrior coal field: Alabama Geol. Survey [Spec. Rept. 1], 571 p. 

--- 1898, Map of the Warrior coal basin with columnar 

sections of formations so far as it carries workable 

coals: Montgomery, Ala., Alabama Geol. Survey. 

--- 1900, Report on the Warrior coal basin: Alabama 

Geol. Survey [Spec. Rept. 10], 327 p. 

McGlamery, Winnie, 1955, Subsurface stratigraphy of northwest Alabama: Alabama Geol. Survey Bull. 64, 503 p. 

McKee, E. D., Crosby, E. J., and others, 1975, Paleotectonic 

inv·estigations of the Pennsylvanian System in the 

United States: U.S. Geol. Survey Prof. Paper 853, 3 v.: 

pt. 1, 349 p.; pt. 2, 192 p.; pt. 3, 60 pls. 

McKee, J. W., 1975, Pennsylvanian sediment-fossil relationship,s in part of the Black Warrior basin of Alabama: 

Alabama Geol. Survey Circ. 95, 42 p. 

Mellen, F. F., 1947, Black Warrior basin, Alabama and 

Mississippi: Am. Assoc. Petroleum Geologists Bull., v. 

31,no. lO,p. 1801-1816. 

Metzger, W. J., 1961, Pennsylvanian stratigraphy of the 

Warrior basin, Alabama: Urbana, Ill., Univ. Illinois, 

Ph.D. thesis, 154 p. 

--- 1965, Pennsylvanian stratigraphy of the· Warrior 

basin, Alabama: Alabama Geol. Survey Circ. 30, 80 p. 

Moore, R. C., chairman, and others, 1944, Correlation of 

Pennsylvanian formations of North America: Geol. Soc. 

America Bull., v. 55, no. 6, p. 657-706 [Correlation 

chart 61]. 

Neathery, T. L., and others, 1969a, Mineral resources map 

of DeKalb County, Alabama: Alabama Geol. Survey 

Map 85, including text. 

--- 1969b, Mineral resources map of Etowah County, 

Alabama: Alabama Geol. Survey Map 86. 
136 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Prouty, W. F., 1909, The Coosa coal field of Alabama: Eng. 

Mining Jour., v. 88, p. 921-923. 

--- 1912, Map of the Coosa coal field: [Montgomery, 

Ala.] Alabama Geol. Survey Geol. Map. 

Read, C. B., and Mamay, S. H., 1964, Upper Paleozoic floral 

zones and floral provinces of the United States: U.S. 

Geol. Survey Prof. Paper 454-K, 35 p. 

Rothrock, H. E., 1949, Geology and coal resources of the 

northeast part of the Coosa coal field, St. Clair County, 

Alabama: Alabama G.eol. Survey Bull. 61, pts. 1 and 2, 

163 p. 

Schlee, J. S., 1963, Early Pennsylvanian currents in the 

southern Appalachian mountains: Geol. Soc. America 

Bull., v. 74, no. 12, p. 1439-1451. 

Squire, Joseph, 1890, Report on the Cahaba coal field: Montgomery, Ala., Alabama Geol. Survey, 131 p. (Includes 

Map of Cahaba coal field and adjacent regions, by 

Joseph Squire and Henry McCalley.) 

Thomas, W. A., 1972, Mississippian stratigraphy of Alabama: Alabama Geol. Survey Mon. 12, 121 p. 

Upshaw, C. F., 1967, Pennsylvanian palynology and age relationships, in A field guide to Carboniferous detrital 

rocks in northern Alabama-Geol. Soc. America, Coal 

Div., 1967 field trip: University, Ala., Alabama Geol. 

Soc., p. 16-20. 

U.S. Bureau of Mines, 1949, Logs of diamond drill holes, Appendix, in Toenges, A. L., and others, Investigation of 

coal deposits in the Fairview and Coal City basins, Coosa 

field, St. Clair County, Alabama: U.S. Bur. Mines Tech. 

Paper 719, p. 53-96. 

Wanless, H. R., 1967, Regional setting of the Alabama coal 

basins, in A field guide to Carboniferous detrital rocks 

in northern Alabama-Geol. Soc. America, Coal Div., 

1967 field trip: University, Ala., Alabama Geol. Soc., 

p. 5-10. 

--- 1975, Appalachian region, in McKee, E. D., and 

Crosby, E. J., coordinators, Introduction and regional 

analys·es of the Pennsylvanian System, Pt. 1 of Paleotectonic· investigations of the Pennsylvanian System in 

the United States: U.S. Geol. Survey Prof. Paper 853, 

pt. 1, p. 17-62. 

Ward, W. E., III, 1977, Jointing in a selected area of the 

Warrior coal field, Alabama: University, Ala., Univ. 

Alabama, unpub. Master's thesis. 

Ward, W. E., III, and Evans, F. E., Jr., 1977, Coal-its importance to Alabama: Alabama Geol. Survey Inf. Ser. 

53, p. 1-26. 
CARBONIFEROUS OUTCROPS OF MISSISSIPPI 

CONTENTS 

Page 

Albstract ----------------------------------------------------------------- 137 

Introduction ------------------------------------------------------------- 37 

History ------------------------------------------------------------------ 38 

Geological setting --------------------------------------------------------- 40 

Carmack Limestone _ __ _ __ _ __ _ _ _ _ _ ___ ___ ____ ___ _ ____ _____ _ _ ____ _ _ _ _ _ __ _ _ _ _ 41 

Iuka Formation ---------------------------------------------------------- 42 

Tuscumbia Limestone _____________________ -------------- ___ __ __ _____ ___ __ 42 

Allsobrook Formation ____ ------------------------------------- ___ ------ ___ 42 

Alllsboro Sandstone --------------------------------------------~---------- 43 

Southward Pond Formation ----------------------------------------------- 43 

Southward Springs Formation ------------------------------------~-------- 43 

Southward Bridge Formation ---------------------------------------------- 43 

Forest Grove Formation -------------------------------------------------- 44 

Highland Church Sandstone Member ----------------------------------- 44 

Selected references ------------------------------------------------------- 44 

ILLUSTRATIONS 

Page 

FIGURE 7. Map showing distribution of Mississippian outcrops in Mississippi ------------------------------- 137 

8. Correlation chart of the Mississippian rocks of Mississippi ---------------------------------------- 39 

III 
THE :MISSISSIPPIAN AND PENNSYLVANIAN (CARBONIFEROUS) SYSTEMS 

IN THE UNITED STATES-ALABAMA AND MISSISSIPPI 

CARBONIFEROUS OUTCROPS OF MISSISSIPPI 

By ALVIN R. BICKER, JR.1 

ABSTRACT 

Carboniferous outcrops in Mississippi are restricted both 

in areal extent and stratigraphic content. Outcrops of Paleozoic rocks are present only in Tishomingo County in the 

northeastern corner of the State. The Carboniferous outcrops include rocks of the Kinderhook, Osage, Meramec, and 

Chester Series of Mississippian age. Although Pennsylvanian 

rocks are present in the subsurface approximately 25 miles 

to the south, none are exposed. 

INTRODUCTION 

The Carboniferous outcrops of Mississippi are restricted to strata of Mississippian age. Late Carboniferous- or Pennsylvanian-age sedimentary rocks are 

present only in the subsurface. Mississippian outcrops are limited to Tishomingo County in the northeastern corner of the State, adjacent to Alabama and 

T·ennessee (fig. 7). Tishomingo County is rectangular, its long axis trending north. It is approximately 

37 miles long and approximately 15 miles wide. The 

county is bounded on the north by the State of Tennessee and the Tennessee River. The eastern boundary is the Mississippi-Alabama State line. 

Most of the Carboniferous outcrops are in the 

northern and eastern parts of the county, along the 

Tennessee River and its tributaries, where overlying 

Cretaceous-age sediments or more recent terraces 

have been eroded. Major tributaries where Carboniferous strata are exposed are Yellow Creek, Indian 

Creek, Bear Creek, and tributaries of Bear Creek, 

mainly Little Bear, Pennywinkle, and Cripple Deer 

Creeks. A few isolated exposures are present in the 

southwestern part of Tishomingo County in the 

drainage system of Mackeys Creek and its tributaries. Mackeys Creek is a tributary of the Tombigbee River, which drains south. Mackeys Creek valley 

1 Mississippi Geological, Economic, and Topographical Survey, Jackson, 

Miss. 39216. 

90' 

50 100 KILOMETERS 

89' 

--~ 

Clllp OF MEXICO 

I 

I 

I 

I 

I 

I 

_L 

I 

I 

I 

I 

I 

FIGURE 7.-Distribution of Mississippian outcrops in 

Mississippi. 

will be the route of the Tennessee-Tom big bee Waterway in this part of Tishomingo County. 

The stratigraphic nomenclature used in this paper 

has not been reviewed by the Geologic Names Committee of the U.S. Geological Survey. The nomen137 
138 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

clature used here conforms with the current usage of 

the Mississippi Geological, Economic, and Topographical Survey. 

HISTORY 

Although previous writers had briefly referenced 

Paleozoic strata as being present in Mississippi, 

Harper (1857) was the first to specifically discuss 

the Paleozoic beds in the State. He reported Carboniferous strata in Tishomingo and Itawamba Counties as extending into the State from neighboring 

Alabama. The only part of the Carboniferous that 

Harper recognized, he designated Mountain Limestone; he considered that this unit consisted of limestone, sandstone, chert (hornstone), and clay. 

Harper recognized and labeled some faunal species 

contained in the limestone and clay. 

Hilgard (1860) (fig. 8) more correctly delineated 

the stratigraphic horizon of the Carboniferous 

strata. He stated that, on the basis of faunal identification, the greater part of the Mississippian outcrops 

were within the limits of the Warsaw and Keokuk 

Limestones. He further stated that observations 

were insufficient to •separate those beds belonging to 

each group. Hilgard, as Harper had earlier, did not 

indicate specific locations of Mississippian outcrops 

as far south as ltawamba County; however, both 

authors indicated Mississippian strata within the 

county on their respective charts or geologic maps. 

Hilgard believed that the Orange Sand overlay the 

Carboniferous in most places; the Tuscaloosa Group 

had not heen designated at that time. However, he 

pointed out that data from water wells suggested 

that the Eutaw Group overlay the Carboniferous at 

certain localities in Tishomingo County. In his introductory paragraph, Hilgard noted diverse dips of the 

Miss.issip·pian strata and ·contemplated the probability of folds extending into Mississippi from Alabama 

and Tennessee. 

Between 1860 and 1905, the area of Paleozoic outcrops must have been obs·erved by other geologists, 

but records of their visits are difficult to find. During 

a visit to northeast Mississippi in the· year 1884, 

Johnson (Smith and Johnson, 1887) noted the presence of gravel, lignite, and clay, which he assigned 

to a formation below the Eutaw. These beds of 

gravel, clay, and lignite were identified by Smith and 

Johnson (1887) as belonging to the Tuscaloosa Formation of Cretaceous age. 

Crider (1906), in a paper on the geology and 

mineral resources of the State, described some of the 

Paleozoic outcrops.. Crider may not have observed 

I outcrops in ~he entire area he desi~nated as containing Paleozoic. As Harper and Hllgard had shown 

earlier, Crider indicated that Paleozoic outcrops extended far south in Itawamba County. The idea of 

Paleozoic rocks being present at the surface in Itawamba County persisted until 1930, when Morse 

restricted the Paleozoic outcrops to Tishomingo 

County. Crider differentiated more of the Paleozoic 

strata than had previous writers. On the basis of 

faunal evidence collected along Yell ow Creek in sees. 

15 and 22, T. 1 S., R. 10 E., in northern Tishomingo 

County and identified by Charles Schuchert and 

E. M. Kindle, Crider was able to identify the oldest 

Paleozoic strata as lower Devonian, correlative with 

the New Scotland of N·ew York. Crider's description 

I 

of an outcrop on Whetstone Creek indicates that he 

recognized other beds that he ·considered to be Devonian in age, but he did not identify the formation. 

Although Crider was influenced by McCalley (1896) 

in his assignment of Mississipp-ian strata, he neglected or chose not to recognize the upper beds as 

the Devonian black shale. Crider identified the lowest Carboniferous strata as the Tullahoma Formation and correlated it with the Tullahoma or Lauderdale chert, as had McCalley of the Alabama Survey. 

He identified the principal materials of the formation as highly siliceous fragmental chert, pulverized 

silica, an.d residual clay. Overlying the Tullahoma 

Formation, Crider recognized a highly fossiliferous 

limestone as the St. Louis Limestone. He suggested 

that a member of the upper part of this interval is 

equivalent to the Ste. Genevieve of Missouri. Crider 

identified the Chester Formation as the uppermost 

Carboniferous in Mississippi. The formation is rep"' 

resented by limestone, sandstone and shale. The one 

section described is near Mingo in southern Tishomingo County. 

Lowe (1919), in a report on the general geology of 

the State, briefly discussed the Paleozoic strata. 

Lowe assigned the name Yell ow Creek beds to the 

Devonian strata underlying the Mississippian. He 

stated that the beds at certain levels consisted of 

dark limestone containing fauna of Devonian age 

that are correlative with those of the New Scotland. 

Immediately overlying the Devonian, Lowe identified the Carboniferous strata as the Lauderdale 

Chert. General locations of outcrops were given. 

Lowe was the first to report the use of the name Tuscumbia for those beds overlying the Lauderdale 

chert that are correlative with the St. Louis. For the 

strata in the Chester series., Lowe used the name 

Hartselle Sandstone, as had the Alabama Survey. In 

this report is the only indication of the Carbonifer-
:2 ALABAMA ALABAMA (/) w w HILGARD CRIDER LOWE MORSE WELCH !;; a: BUTTS THOMAS 

> w 1860 1906 1915 1930 1959 1926 1972 (/) (/) 

PARKWOOD PARKWOOD 

FORMATION FORMATION I-------·-

PENNINGTON PENNINGTON 

FORMATION FORMATION 

BANGOR 

LIMESTONE 

w 

KHARTSELLE' 

_. CHESTER~N cHESTER HARTSELLE FOREST GROVE FLOYD HARTSELLE < :I: 

FORMATION SANDSTONE FORMATION SHALE SANDSTONE (/) I ~NDSTO~>- HIGHLAND CHURCH GOLCONDA 0 MEMBER FORMATION > SOUTHWARD BRIDGE ~I CYPRESS· g PRIDE 

FORMATION SANDSTONE u. MOUNTAIN 

z SOUTHWARD SPRINGS GASPER ~, FORMATION 

< SANDSTONE FORMATION 

a: SOUTHWARD POND BETHEL ~I MONTEAGLE a.. FORMATION SANDSTONE ~I LIMESTONE (/) AlLSBORO SANDSTONE STE. GENEVIEVE (/) ALSOBROOK FORMATION LIMESTONE i (/) f------ 1----------t-----..,..---f-------·-

!!2 

:2 · WARSAW ST. LOUIS TUSCUMBIA IUKA TUSCUMBIA TUSCUMBIA I TUSCUMBIA MERAMECIAN LIMESTONE LIMESTONE LIMESTONE FORMATION LIMESTONE LIMESTONE 1/ LIMESTONE 

1------

OSAGEAN KEOKUK TULLAHOMA LAUDERDALE 

LIMESTONE FOR!\11ATION CHERT FORT PAYNE 

CHERT 

r----- 1--------- FORT PAYNE 

CARMACK FORT PAYNE CHERT 

LIMESTONE CHERT 

KINDERHOOKIAN 1--------- MAURY 1--------

WHETSTONE SHALE CHATTANOOGA 

BRANCH SHALE CHATTANOOGA SHALE MAURY 1--------- SHALE t-------- SHALE 

FIGURE B.-Correlation chart of the Mississippian rocks of Milssissippi. 

MC NAIRY COUNTY 

TENNESSEE 

RUSSELL 

1972 

-.....w 

FORT PAYNE 

FORMATION 

UPPER 

)· FORT PAYNE 

( FORMATION 

I LOWER 

lfHATTANOOG~- SHALE 

-----

THIS 

PAPER 

FOREST GROVE 

FORMATION 

HIGHLAND CHURCH MEMBER 

SOUTHWARD BRIDGE 

FORMATION 

SOUTHWARD SPRINGS 

SANDSTONE 

SOUTHWARD POND 

FORMATION 

ALLSBORO SANDSTONE 

ALSOBROOK FORMATION 

TUSCUMBIA 

LIMESTONE 

v IUKA FORMATION 

CARMACK 

LIMESTONE 

1--------- CHATTANOOGA 

SHALE 

1---------

·0 

> 

~ 

·t:d 

0 

z 

1-4 

"%j 

tzj 

~ 

0 

.q 

rJl 

0 

d 

1-3 

0 

~ 

0 

'"d 

rJl 

0 

l'%j 

is: 

1-4 

rJl 

rJl 

1-4 

rJl 

rJl 

1-4 

'"d 

'"d 

1-4 

1--1 

~ 

(,0 
140 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

ous strata that supposedly crop out in southern Itawamba County; Lowe stated that a sandstone member crops out on Bull Mountain Creek in northern 

Monroe County and adjacent regions. 

The most complete record of Paleozoic rocks that 

crop out within Mississippi was given by Morse 

(1930). Many of the outcrops that Morse reported 

have since been partly or entirely inundated by the 

water of Pickwick Lake. Most of those that are 

partly in undated are so isolated that they are best 

reached by water. Most of the Devonian outcrops 

have been completely inundated; only a few feet of 

Devonian strata is visible· above water level at isolated locations. Morse nam·ed the upper part o.f the 

Devonian the Whetstone Branch. The type locality 

is a small stJ~eam by the same name in sec. 31, T. 1 

S., R. 11 E. Although Morse considered the Whetstone Branch to be in part correlative with the Chattanoo:ga and to be Devonian in age, he reported the 

presence of fauna indicative of early Mississippian 

age in the upper section of the formation. He was 

skeptical o.f assigning the· upper section to the Missrissipian because he could not recognize· a stratigraphic break between the upper and lower sections ; 

therefore, he as·signed the s~ection to the Devonian. 

Morse gave the lower part of the Mississippian 

the name Carmack, stating that the formation is 

largely Kinderhookian in age. He recognized pronounced unconformities at the base and top of the 

Carmack. He included all strata overlying the Carmack, between the Carmack and the base of the 

Chester, in the Iuka Terrane (now luka Form~­

tion), a unit consisting mostly o.f residual material 

in the form of clay and chert fragments. Outcrops 

included by Morse in the Iuka that contain unleached material are present only in western Alabama near the Mississippi State line. In Mississippi, 

strata of both the Fort Payne and Tuscumbia Formations were included in the Iuka Terrane by 

Morse. That part of the Iuka which Morse described 

in the south wall o.f Cripple Deer Creek, contained 

faunal evidence that indicated a St. Louis age. Other 

writers used the nam·e Tuscumbia for correlative 

strata in Alabama and the subsurface of Mississippi. 

Overlying his Iuka Terrane, Morse (1930) identified strata of the Chester Group, which he divided 

into six formations and to which he assigned names. 

In ascending order, these formations were the Alsobrook, Allsboro, Southward Pond, Southward 

Springs, Southward Bridge, and Forest Grove. Some 

of the formations are restricted, both at the outcrop and in the subsurface, and the names proposed 

by Morse are used only locally by few geologists. The 

uppermost Mississippian out~rops described by 

Morse were o.f the Highland Church Sandstone 

Member of the Forest Grove Formation. The most 

southerly outcrops of Highland Church that Morse 

desc;ribed are in T. 7 S., R. 9 E., in the southwest 

part of Tishomingo County. The Highland Church is 

correlative with the Hartselle of Alabama; many 

geologists working in both areas prefer the name 

Hartselle when describing the strata in Mississippi. 

Russell, during geological investigations for a propos·ed nuclear generating plant site for the Tennessee Valley Authority (1977), mapped an area 

in cooperation with TV A geologists in northern 

Tishomingo County. The area was designated as 

the Yellow Creek Plant Site. The site encompasses 

an area within a 5-mile radius centered in sec. 35, 

T. 1 S., R. 10 E. Russell and others (1972) previously had mapped quadrangles immediately to the 

north in Tennessee and had retained formational 

names in use in that State for strata present at the 

Yellow Creek Site. Russell showed the Chattanooga 

to be Devonian and Miss'i·ssippian in .age. The Mis.-

s.issippian section overlying the Chattanooga had 

been designated the _:fort Payne Formation. Russell 

divided this section infu the Lower Fort Payne and 

the Upper Fort Payne. The Lower Fort Payne is 

correlative with the strata ~hat Morse designated as 

the Carm.ack; the Upper Fort Payne is equivalent 

to the lower part of Morse's Iuka Terrane. 

T.his paper is. presented as a f'"Jide to those who 

may have some inter~st in the Carboniferous outcrops within the State of Mississippi. It does not 

attempt to alter the nomenclature of the Mississippian s.trata or to resolve differences in nomenclature as used by different investigators. Formational 

names used herein are those deemed most satisfactory for the facies that appear at the surface in 

Mississippi. 

GEOLOGICAL SETTING 

Most geologists assign a Devonian and Mississippian age to the Chattanooga Shale. Morse ( 1930) 

gave the name Whetstone Branch to these sedimen.tary rocks and stated that faunal evidence indicated the lower part of the section to be undoubtedly 

Devonian. Although at some localities, the upper 

part of the formation appears to be closely associated with the Mississippian, Morse could not identify an unconformity within the section; therefore? 

he included the whole section in the Devonian. 
CARBONIFEROUS OUTCROPS OF MISSISSIPPI I41 

The Car.mack Limestone, as named by Morse is 

the lowermost Mississippian strata. It unconf·ormably overlies the Chattanooga in some areas of outcrop. At several localities. along the west bank of 

Pickwick Lake between Yell ow Creek and Indian 

Creek in sec. 30, T. 1 S., R. 11 E., gently dipping 

thin-bedded Carmack Limestone can be seen above 

highly ·Contorted more steeply dipping Chattanooga 

strata. The unconformable relationship between the 

Carmack and the Chattanooga is not a·s apparent at 

the few outcrops that are visible at other localities 

This is due in part to the small thickness of Chattanooga that is exposed above the water level of Pickwick Lake. In the most extreme northern outcrops, 

the Carmack Limestone overlies strata of Early 

Devonian age. In his cliff section, in sec. 22, T. 1 S., 

R. 10 E., Morse (1930, p. 21) showed the Carmack 

Limestone to overlie Devonian strata to which he 

assigned the name Island Hill. TV A geologists 

( 1977) as·signed the same De·vonian strata to the 

Ross Formation and showed that the Lo·wer Fort 

Payne of Mississitppdan age overlies the Devonian 

unconformably. 

The Mississippian is overlain by rocks of Cretaceous age or •by Quaternary terrace materials. 

Cretaceous strata overlap the Mississippian and are 

present at the outcrop. except in those localities 

where erosion has removed the Cretaceous strata 

and fluvial Qua·ternary sediments have been deposited. In the northernmost outcrops, sediments 

of the Eutaw Group of Cretaceous age overlie the 

Carmack Limestone. Southward, succeedingly older 

Cretaceous sediments are in contact with progressrively younger Mississippian beds. At the· southe·rnmost outcrops, strata of the Tuscaloosa Group overlie the Hartselle or Highland Church Sandstone 

Member of the Ches·ter Series. 

The Missis·sippian outcrops are near the eastern 

edge of the Mississippi Embayment, a southwardplunging structural trough that formed in Late 

Cretaceous-early Tertiary ·time. The axis of the 

trough coincides roughly with the present course of 

the Mississippi River. Post-Paleozoic te·ctonics and 

the overlying younger sediments obscured much of 

the evidence of late Paleozoic struotural movement. 

Lower Mississippian rock types suggest deposition 

on a broad relatively stable shelf. Regional dip of 

the outcrops is to the south and southeast, showing a 

homoclinal fe3!ture having minor undulations. This 

feature may have been a broad shelf south of the 

Pas·cola arch, a :positive feature between the Ozark 

and Nashville domes. Northward u.pdip· thinning of 

pre-Mississippian strata suggests a po.sitive feature 

to· the north, on which the Miss.issippian strata onlapped, and indicates the presence of the Pascola 

arch at the time of Mississippian deposition. 

Although faults. have not been ·mapped in the outcrop area, the location and attitude of some of the 

Miss·issippian strata is highly .suggestive of faulting. 

In addition, meager subsurface control indicates 

faulting involving M.ississ,ippian strata in the southcentral part o.f Tishomingo County. This interpreted 

faulting is probably post-Mi·ssissippian; however, 

additional information is needed before a more accurate date can be assigned. 

CARMACK LIMESTONE 

The name Carmack Limestone was. introduced by 

Morse (1930) for that strata overlying the Devonian-age Chattanooga (Whetstone Branch). The 

strata are correlative with the basal Fort Payne of 

Alabama (Butts, 1926; Thomas, 1972a) and the 

Lower Fort Payne of Tennessee (Russell and others, 

1972). Also correlative, in part, is the St. Joe Formation, the basal member of the Iowa Series, which 

is downdip in the subsurface (Welch, 1959). The 

name Fort Payne has been used in the oil industry. 

Carmack Limestone is preferred herein because of 

the lithologic difference between these strata and 

those of the basal Fort Payne of Alabama. Thomas 

r~ported the Fort Payne of Alabama to consist of 

finely crystalline to· microcrystalline siliceous limestone and smoky chert (the chert content o.f fresh 

rock being 50 percent), whereas the Carmack is 

predominantly a thin-bedded fine-grained, shaly 

limestone. When fresh, the limestone is usually gray 

to dark gray, weathering to brownish gray. 

At the surface, the formation has a maximum 

thickness of 100 feet. Morse ( 1930) described 81.5 

feet of Carmack at the cliff section. before its inundation by Pickwick Lake. Other outcrops contain intervals that are covered by colluvial material, and 

the entire thickness o.f the Carmaok section cannot 

be observed. Data from test wells within the outcrop area ·Substantiate the maximum thickness ass:igned to the outcrop sections. Apparently the formation thins southward in the subsurface. Data 

from a test well in sec. 23, T. 3 S., R. 10 E., shows 

the formation to be 50 feet thick. 

Outcrops of Carmack are numerous along the 

shoreline of the main body o.f Pickwick Lake, the 

Yellow Creek Embayment, and in the valleys of 

·streams that drain into the lake. Outcrops of the 
I42 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Carmack are not visible south of the latitude of sec. 

16, T. 2 S., R. 11 E. 

IUKA FORMATION 

The name Iuka Terrane was introduced by Morse 

( 1930) to include that section of Mississippian 

strata between the underlying Carmack Limestone 

and the base of the overlying rocks o.f the Chester 

series. The unit is now ca.Iled the Iuka Formation. 

The section is correlative writh the Fort Payne Chert 

and the Tuscumbia Limestone of Alabama (Thomas, 

1972a) and, !in part, with the Upper Fort Payne of 

Tennessee (Russell and others, 1972). In Mississippi, the formation consists of s~mall to large blocks 

of residual chert interbedded w,ith residual clay; in 

some localities, it contains beds of amorphous srilica. 

The residual chert is the result of leaching of the 

calcium carbonate fraction o.f the original formation. In the northern outcrops., the formation is the 

residual material resulting from leaching of the 

truncated Fort Payne. To the south, the material 

present in the outcrops is progressively younger. 

In the latitude o.f sec. 15, T. 4 S., R. 11 E., the formation contains residual material who.se faunal content identifies this part of the Iuka as being correlative with the Tuscumbia Limestone. Because of the, 

lithologic similarities and insufficient faunal content, 

the two for·mations cannot be differentiated at the 

surface where they are present in their residual 

state. 

Morse (1930) stated that at a few outcrops, evidence of pre-Chester erosion at the top of the Iuka 

indicates an unconformity. Subsurface data from 

oil test wells. in sees. 15 and 21, T. 4 S., R. 11 E .. , 

suggest the presence of the unconformity. The 

southernmost well, in sec. 21, has competent bedded 

material that can be differentiated :into the resp·ective Fort Payne and Tuscumbia Formations. Other 

well data in the vicinity include a stratigraphic section that contains residual Iuka mater,ial (-probttbly 

Tuscumbia equivalent) underlying Chester beds, 

suggesting possible pre-Chester leaching. 

Thickness of the Iuka in the northern area o.f outcrop is approximately 100 feet. Near the· southern 

edge of the outcrop, the formation has a thickness 

o.f 200 feet. 

TUSCUMBIA LIMESTONE 

Morse ( 1930) chos·e not. to differentiate the Tuscumbia Limestone from the Iuka Terrane, although 

he recognized a few thin limestone beds present at 

the surface in the southern part of the· Iuka outcrop. Even though Morse identified the materials 

as correlative with the Tuscumbia or St. Louis 

Limestone, he included ,it with the Iuka. 

In 1970, a limestone quarry was opened in sec. 

22, T. 4 S., R. 11 E., in the area of outcrop of chystalline limestone that Morse ( 1930) included in the 

I uka. The quarry sho.ws a comp~tent section of crystalline limestone that should be correlative with the 

Tuscumbia Limestone. 

T:he limestone is light gray, medium to coarse 

crystalline, and contains m·any fossil imprints and 

light-gray ·chert. Scattered joints and small void 

spaces are filled with asphaltic material. 

The full thickness of the limestone has not been 

exposed, nor has the underlying contact been 

reached. However, test-hole data indicate that the 

Tuscumbia in this area is more than 100 feet thick. 

The formation dips to the south, and in the latitude 

of the T:ishomingo-Itawamba County boundary, subsurface data show the Tuscumbia section to be 70 

feet thick. 

Surface exposures that can be identified as Tuscumbia Limestone are restricted to the vaUey of 

Cripple Deer Creek. 

ALSOBROOK FORMATION 

Morse ( 1930) assigned the basal 85 feet of the 

Chester Ser,ies to the Alsobrook Formation. The 

formation is correlative with the St. Genevieve of 

Alabama (Butts, 192.6) or the basal section of the 

Pride Mountain o.f Alabama (Thomas, 1972a). The 

type locality and most exposures are east of the 

Mississippi-Alabama State line near the small village of Allsboro. 

The formation, as described by Morse ( 1930), 

consists of 8 feet of highly fossiliferous limestone 

overlain by 44 feet of green clay shale. Overlying the 

shale is a sandstone bed 36 feet thick, which in turn 

is overlain by a 5-foot bed of clay shale. Faunal 

content of the limestone dearly indicates a Chester 

age for the basal limestone. 

In Mississippi, outcrops of the Alsobrook Formation are restricted to- the valley of Cripple Deer 

Creek, where widely scattered small outcrops of 

thin beds of Mmestone are overlain by gre·en shale. 

The limestone does not ·contain faunal evidence .that 

would definitely indicate the age of the strata; however, the .stratigraphic position of the limestone 

relative to the nearby Tuscumbia Limestone 

strongly suggests a basal Chester section. The sandstone de·signated the Cripple Deer Sandstone Member ,is nort present at the surface in Mississip·pi. Sub-
CARBONIFEROUS OUTCROPS OF MISSISSIPPI !43 

surface data from a test well on the divide immediately south of Cripple Deer Creek, includes a sandstone section at the stratigraphic position of the 

Cr.ipple Deer. This sandstone member appears to he 

correlative with the Lew.is Sandstone, which produces hydrocarbons to the south in Monroe County, 

Miss. 

ALLSBORO SANDSTONE 

The 3-foot section of sandstone above the Alsobrook Formation at the type locality was designated 

the Allsboro Sandstone by Morse (1930). The Allsboro, together with the Cripple Deer Sandstone 

:Member, is correlative with the Bethel of Alabama 

(Butts, 1926) and with the lower sandstotie member 

of the Pride Mountain of Alabama (Thomas, 1972a). 

The type locality in Alabama is the same as that 

given for the Alsobrook Formation; other outcrops 

of Allsboro Sandstone described are also in Alabama. 

Isolated outcrops of sandstone within the valley of 

Cripple Deer Creek may be Allsboro, but exact 

stratigraphic position of these outcrops is undetetmined. Most of the Paleozoic beds are covered by 

Cretaceous sand and gravel, which prevents an accurate assessment of their position. 

Morse described the Allsboro Sandstone at the 

type locality as being dark gray, coarse grained, and 

containing a petroleum residue. Other de1scriptions 

indicate that the sandstone varies in thickness and 

character at different localities. Although this variation was noted by Morse (1930, p. 131), he still chose 

to separate the Allsboro Sandstone from the Cripple 

Deer Sandstone Member. The variation suggests a 

facies change, which may indicate that perhaps the 

Allsboro and the Cripple Deer should have been 

included in the same unit. 

SOUTHWARD POND FORMATION 

Overlying the Allsboro Sandstone is a shale se- · 

quence separated by thin beds of limestone. The entire sequence is approximately 75 feet thick; the intervening limestone beds are 9, 1, and 3 feet thick. 

Morse (1930) designated this section as the Southward Pond Formation and assigned the limestone 

beds the designations A, B, and C. The section is 

correlative with the Gasper Formation of Alaba.ma 

(Butts, 1926) and with that part of the Pride Moun 

tain between the lower sandstone unit and· the middle sandstone unit (Thomas, 1972a). 

Both the limestone and shale are extremely fossiliferous and at different localities afford the best 

collecting of Paleozoic fauna of all the· Mississippian 

strata. The basal limestone is a dark-gray, very 

oolitic, highly fossiliferous, slightly asphaltic unit 

that is distinctive and easily recognized. The middle 

and upper limestone beds are dark-gray crystalline 

fossiliferous units but are not as easily recognizable 

as· the lower limestone unit. The shale units are 

usually green, fossiliferous, and at some localities 

very limy. 

The type locality is near the northwest part of 

Cypress Pond, a low swampy area that was an old 

meander of Bear Creek, in sec. 17, T. 5 S., R. 11 E. 

At the time of Morse's investigation, the low area 

was named Southward Pond. Other outcrops of the 

Southward Pond Formation are in the valley of 

Pennywinkle Creek and at several scattered outcrops in McDougle Creek in the western part of 

Tishomingo County. The outcrops in Pennywinkle 

Creek afford the best fossil-collecting area in the 

Paleozoic outcrop belt. 

SOUTHWARD SPRINGS FORMATION 

Overlying the Southward Pond Formation is a 

sandstone section that Morse (1930) designated the 

Southward Springs Sandstone and that is now called 

the Southward Springs Formation. The Southward 

Springs is correlative with the Cypress of Alabama 

(Butts, 1926) and with the middle sandstone unit 

of the Pride Mountain Formation (Thomas, 1972a). 

Outcrops of the Southward Springs are restricted 

to the area north and south of Cypress Pond. Outcrops north of the pond are in the southwest quarter 

of sec. 8, T. 5 S., R. 11 E.; outcrops south of the 

pond are in sec. 18. 

The northern exposure consists of 26 feet of shaly 

sandstone and ~andy shale, yellowish buff, weathering to yellowish red. The upper part of the section 

is calcareous and fossiliferous. At the southern exposure, only about 15 feet of the section can be 

observed. Both exposures are covered partly by colluvium, and the entire section cannot be seen. Fossils from both exposures are mainly brachiopods. 

The stratigraphic position of the Southward' 

Springs Formation suggests that the sandstone is 

correlative with the Evans sand, which produces 

hydrocarbons in Itawamba and Monroe Counties, 

south of the outcrop area. 

SOUTHWARD BRIDGE FORMATION 

South of Cypress Pond, near the abandoned 

bridge crossing Bear Creek, in the valley wall of the 

creek, is an exposure of alternating shale, sandy 

shale, and limestone, which Morse (1930) desig-
144 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

nated the Southward Bridge Formation. The Southward Bridge Formation is correlative with the 

Golconda of Alabama (Butts, 1926) and with the 

upper part of the Pride Mountain Formation 

(Thomas, 1972a) . 

The whole interval is not exposed at Southward 

Bridge. The upper limestone member is missing 

here but is present a short distance upstream in 

the Bear Creek valley. The basal shale section is 

black, carbonaceous, and contains thin limestone 

beds. Upper shale intervals are blue-gray, calcareous, sandy, and fossiliferous. The limestone members are bluish gray, massive, fine crystalline, and 

fossiliferous. Thickness of the entire interval is 

approximately 90 feet. The limestone members are 

4 to 6 feet thick, and the intervening shale beds are 

as much as 40 feet thick. 

The larger outcrops of the Southward Bridge 

Formation are in the valley of Bear Creek in T. 5 S., 

R. 10 and 11 E. However, in western Tishomingo 

County, small outcrops are present in the bed of 

McDougle Creek in sec. 5, T. 5 S., R. 10 E. At this 

location, greenish-gray shale and brown crystalline 

fossiliferous limestone can be observed in the bed 

of the creek. Colluvial material covers much of the 

area, and only thin beds of Paleozoic rocks are 

visible. 

FOREST GROVE FORMATION 

HIGHLAND CHURCH SANDSTONE MEMBER 

The section of shale, shaly sandstone, and sandstone overlying the uppermost limestone member of 

the Southward Bridge Formation was named the 

Forest Grove Formation by Morse (1930). A persistent massive sandstone at the top of the interval 

has been designated as the Highland Church Sandstone Member. The basal part of the Forest Grove 

Formation has been correlated with the Golconda 

of Alabama (Butts, 1926) or with the upper part 

of the Pride Mountain (Thomas, 1972a). The massive Highland Church is correlative with the Hartselle Sandstone of Alabama (Butts, 1926, Thomas, 

1972a). 

The basal section below the massive Highland 

Church contains alternating beds of gray to darkgray, sandy, slightly calcareous shale and thin beds 

of fine-grained sandstone. Both the shale and sandstone may contain fossils at some localities. Lithology of the massive Highland Church is generally 

consistent throughout its outcrop area. The sandstone is generally light colored, well sorted, fine to 

medium-grained, locally calcareous, and fossiliferous. 

Outcrops of the Highland Church and the underlying shale of the Forest Grove are numerous in the 

valley of Bear Creek in T. 5 and 6 S., R. 10 and 

11 E. Outcrops of the Highland Church are present 

also in the valley of Mackeys Creek in southwestern 

Tishomingo County in S. 26, T. 6 S., R. 9 E. The 

outcrops of Highland Church in Mackeys Creek are 

the most southerly and the youngest Mississippian 

strata present at the surface. 

Thickness of the combined interval of the basal 

Forest Grove and the overlying Highland Church 

is approximately 125 feet. At the outcrop, only 25 

to 30 feet of Highland Church and as much as about 

50 feet. of the basal Forest Grove can be observed. 

Data from core holes in the area of Mackeys Creek 

show the Highland Church to be 47 feet thick and 

the basal Forest Grove to be 77 feet thick. 

Toward the south in the subsurface, the Highland 

Church and Forest Grove, like much of the Chesterage strata, pinch out or are not identifiable because 

of facies changes. In the latitude of central Itawamba County, the Highland Church-Forest Grove 

section probably grades into the marine carbonate, 

the Bangor limestone, and is not present as a separate identifiable unit. 

SELECTED REFERENCES 

Bramlette, M. N., 1925, Paleozoic formations penetrated by 

wells in Tishomingo County, northeastern Mississippi: 

U.S. Geol. Survey Bull. 781, p. 1-10. 

Butts, Charles, 1926, The Paleozoic rocks, in Geology of Alabama: Alabama Geol. Survey Spec. Rept. 14, p. 41-230. 

Crider, A. F., 1906, Geology and mineral resources of Mis-

!Sissippi: U.S. Geol. Survey Bull. 283, 99 p. 

Harper, Lewis, 1857, Preliminary report on the geology and 

agriculture of the State of Mississippi: Jackson, Miss., 

350 p. 

Hilgard, E. W., 1860, Report on the geology and agriculture 

of the State of Mississippi: Jackson, Miss., 391 p. 

Johnson, V. C., 1975, Fracture patterns· of the Yellow Creek 

area, Mississippi: Southea,stern Geology, v. 16, no. 3, 

p. 173-177. 

Lowe, E. N., 1919, Mississippi, its geology, geography, soil, 

and mineral resources: Mississippi Geol. Surve,y Bull. 

14, 346 p. 

McCalley, Henry, 1896, On the Tennessee Valley region, Pt. 

1 of Report on the valley regions of Alabama (Paleozoic strata): Alabama Geol. Survey [Spec. Rept. 8], 

436 p. 

McGlamery, Winnie, 1955, Subsurface 'stratigraphy of northwest Alabama: Alabama Geol. Survey Bull. 64, 503 p. 

Milhous, H. C., 1959, Well logs in Tennessee: Tennessee Div. 

Geology Bull. 62, 606 p. 

Moore, G. K., and Harris, H. B., 1962, Geologic map of 

Colbert County, Alabama: Alabama Geol. Survey Map 

20. 
CARBONIFEROUS OUTCROPS OF MISSISSIPPI 145 

Morse, W. C., 1930, Paleozoic rocks: Mississippi Geol. Survey Bull. 23, 212 p. 

Peace, R. R., Jr., 1963, Geologic map of Franklin County, 

Alabama: Alabama Geol. Survey Map 22, text. 

Russell, E. E., Wilson, C. W., Jr., and Jewell, J. W., 1972, 

Geologic map and mineral resources summary of the 

Pickwick quadrangle, Tennessee: Tennessee Div. Geology 

Geol. Map GM 24-SW. 

Smith, E .A., and Johnson, L. C., 1887, Tertiary and Cretaceous strata of the Tuscaloosa, Tombigbee, and Alabama Rivers: U.S. Geol. Survey Bull. 43, 189 p. 

Tennessee Valley Authority, 1977, Yellow Creek nuclear 

plant, geology and seismology: Tennessee Valley Authority Prelim. Safety Analysis Rept., Sec. 2.5, 69 p. 

Thomas, W. A., 1972a, Mississippian stratigraphy of Alabama: Alabama Geol. Survey Mon. 12, 121 p. 

--- 1972b, Regional Paleozoic stratigraphy in Mississippi 

between Ouachita and Appalachian Mountains: Am. 

Assoc. Petroleum Geologists Bull., v. 56, no. 1, p. 81-

106. 

Welch, S. W., 1959, Mississippian rocks of the northern 

part of the Black Warrior basin, Alabama and Mississippi: U.S. Geol. Survey Oil and Gas Inv. Chart OC62, with text. 

Wilson, C. W., Jr., 1949, Pre-Chattanooga stratigraphy in 

central Tennessee: Tennessee Div. Geology Bull. 56, 

407 p. 
The Mississippian and Pennsylvanian 

(Carboniferous) Systems in the United StatesMichigan 

By GARLAND D. ELLS 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1110-J 

Prepared in cooperation with the 

Geological Survey Division 

Michigan Department of Natural Resources 

Historical review and summary of areal, stratigraphic, 

structural, and economic geology of Mississippian and 

Pennsylvanian rocks in Michigan 

UNITED STATES GOVERNl\1ENT PRINTING OFFICE, WASHINGTON 1979 

CONTENTS 

Page 

Abstract ----------------------------------------------------------------- J1 

Introduction ------------------------------------------------------------- 1 

Early geological work ----------------------------------------------------- 2 

Mississippian System ______ ----------------------------------------------- 2 

Mississippian Formations _ _ _ __ __ __ _ _ __ __ __ _ _ ____ __ _ _ _ _ _ _ __ _ _ _ _ __ _ ___ __ 7 

Pennsylvanian System ---------------------------------------------------- .9 

Pennsylvanian Formations _ _ ___ _ _ __ _ _ _ _ __ __ _ _ ___ _ _ _ __ __ __ __ _ _ _ _ _ _ _ _ _ _ _ 10 

Mississippian-Pennsylvanian environments of deposition --------------------- 12 

Economic products ----- ________ ------------------------------------------- 14 

Outcrop localities --------------------------------------------------------- 15 

References cited ---------------------------------------------------------- 16 

ILLUSTRATIONS 

Page 

FIGURE 1. Map showing distribution of Mississippian, Pennsylvanian, and remnant Jurassic bedrock in the Southern 

Peninsula of Michigan ------------------------------------------------------------------------ J3 

2. Map of the northwest-trending Howell anticline ----------------------------------------------------- 6 

TABLE 1. 

2. 

TABLES 

Mississippian nomenclature, 194 7-64 _______________________________________________________________ _ 

Pennsylvanian nomenclature, 1861-1975 ------------------------------------------------------------

III 

Page 

J4 

10 
THE MISSISSIPPIAN AND PENNSYLVANIAN (CARBONIFEROUS) 

SYSTEMS IN THE UNITED STATES-MICHIGAN 

By GARLAND D. ELLS1 

ABSTRACT 

The Michigan basin covers about 315,968 km2

• (122,000 

sq mi). On the west it is bounded by the Wisconsin arch and 

Wisconsin dome, and to the north by the Canadian shield. 

To the southwest it is separated from the Indiana-Illinois 

basin by the Kankakee arch, and to the southeast it is cutoff 

from the Appalachian basin by the Findley and Algonquin 

arches. The basin contains Cambrian, Ordovician, Silurian, 

Devonian, Mississippian, Pennsylvanian, and remnant Jurassic sediments. Pleistocene glacial drift, as much as 366 m 

(1,200 ft) thick, blankets virtually all bedrock. 

Carboniferous rocks, generally separated into Mississippian and Pennsylvanian in Michigan, form most of the. bedrock surface. The combined thickness of these rocks is about 

1,158 m (3,800 ft). Because of limited outcrops and the fact 

that the complete sequence cannot be studied in outcrop, 

Carboniferous rocks are best known from subsurface investigations made possible from thousands of well records. 

Though formation names have been derived from outcrop 

localities, the thickness and characteristics of the rock units 

have been determined by subsurface studies. 

Studies have shown that Mississippian rocks are of marine 

origin, were deposited under different environments of deposition, and that an erosional unconfonnity of considerable 

magnitude separates Mississippian strata from those of the 

overlying Pennsylvanian sy.stem. Pennsylvanian rocks are 

terrestrial and marine and were deposited under several 

modes of environment. The original extent and thickness of 

Pennsylvanian rocks in Michigan is unkown. Also dissected 

and partly eroded before Pleistocene glaciation, they are now 

confirmed to the basin interior and cutoff from correlative 

rocks in other basins. Before Pleistocene glaciation, Jurrassic 

sediments were deposited over part of the eroded surface. 

Most of Michigan's Carboniferous studies have been made 

with the objective being the exploitation of the contained 

resources. The nomenclature applied to these rocks has been 

guided to a considerable extent by the needs of industry 

rather than from an academic point of view. Regional and 

inter-basin correlations have been made on the basis of 

fossil assemblages and similar lithologies. Terms such as 

"Red Rock," "Triple Gypsum," "Stray Sandstone," serve a 

useful purpose in the search for economic products. Economic 

products currently extracted from Michigan's Mississippian 

rocks include shales, limestone, sandstone·, gypsum, natural 

brines, oil and natural gas, and in some areas, freshwater. 

In the past Pennsylvanian rocks have provided bituminous 

coal and small amounts of natural brines. Current economic 

products are shales and freshwater supplies. 

INTRODUCTION 

The basin-shaped characteristics of the depositional province known as the Michigan basin have 

been recognized for nearly 140 years. The basin, 

as generally defined, includes the Southern Peninsula and eastern part of the Northern Peninsula, 

eastern Wisconsin, northeastern Illinois, northern 

Indiana, northeastern Ohio, and western Ontario. 

The basin covers about 315,968 km2 (122,000 sq mi), 

part of which is covered by Lakes Michigan, Huron, 

St. Clair, and the Michigan part of Lake Erie·. The 

basin is flanked on the west by the Wisconsin arch 

in central Wisconsin and its northern extension the 

Wisconsin dome; on the north and northeast by the 

Canadian shield ; on the east and southeast by the 

Algonquin arch in Ontario and the Findlay arch in 

northern Ohio; and on the southwest by the Kankakee arch in northern Indiana and northeastern 

Illinois. 

Nearly all_Paleozoic systems are present in the 

basin as well as an area of remnant Mesozoic rock. 

Except for small scattered outcrops, the bedrock 

surface of the basin is covered with glacial drift deposited during the Wisconsin stage of the Pleistocene. The drift is as much as 366m (1,200 ft) thick 

in some areas, especially where parts of thick terminal moraines may overlie preglacial valleys. Mississippian, Pennsylvanian, and Jurassic sediments 

form most of the truncated bedrock surface of the 

Southern Peninsula. Not all formations outcrop. 

Those that do are of small extent, are widely scattered, and limited to areas of thin drift. 

The stratigraphic succession of rocks in the Michigan basin is best known from subsurface studies 

made possible from the records of thousands of oiland gas-well borings and other types of wells drilled 

over the years. Because of limited outcrops which 

seldom expose more than a few meters of vertical 

1 Geological Survey Di.vision, Michigan Department of Natural Resources, 

Lansing, Mich. 48909. 

J1 
J2 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

section, even in manmade openings such as quarries, 

most of the Mississippian and Pennsylvanian rock 

units have been measured from well-record studies. 

The formation names were derived from localities 

where the rocks wer·e first noted and ~studied. 

Complete sections of Mississippian and Pennsylvanian rocks are not found in outcrop, nor are the 

contacts between formations visible at the surface. 

The combined thickness of these rocks is about 1,158 

m (3,800 ft). Because of shifting depocenters during 

several periods of sedimentation, erosional unconformities between Mississippian, Pennsylvanian, 

and Jurassic rock, and erosion before Pleistocene 

time, the combined thickness is not found in any 

one locale. The distribution of Carboniferous and 

Jurassic bedrock beneath unconsolidated Pleistocene glacial deposits is shown in figure 1. 

Because of the mantle o.f glacial drift, the events 

following deposition of Carboniferous rocks are not 

well known. Subsurface investigations show that a 

major unconformity exists at the top of Mississippian rocks, at the top of Pennsylvanian rocks that 

overiie the Mississippian, and at the top of a small 

area of Jurassic sediments that immediately overlie 

a part of the eroded Pennsylvanian section. The 

truncated bedrock surface was scoured and modified 

by continental glaciers during the Pleistocene 

Epoch. Studies show that the preglacial bedrock 

surface was greatly incised by valley systems whose 

major tributaries led to larger preglacial valleys 

now occupied by Lakes Michigan and Huron. Bedrock elevations suggest two stages of uplift as 

evidenced by peneplained surfaces. On the basis of 

deformation of the Lake Algonquin shoreline, one 

of several ancient Great Lakes shorelines, an unwarp has been postulated for much of the northeastern part of the Southern Peninsula. The up•warp 

of the land took place in response to withdrawal of 

the Pleistocene ice sheet (Stanley, 1945, pp. 11-13). 

Present-day stream channels are incised in glacial 

drift and follow a haphazard pattern which may be 

influenced by glacial features ·such as moraines. In 

a few areas, where drift is thin, streams cut through 

bedrock and may be channeled through part of their 

course in preglacial valleys. 

The stratigraphic nomenclature used in this paper 

has not been reviewed by the Geologic Names Committee of the U.S. Geological Survey. The nomenclature used here conforms with the current usage 

of the Geological Survey Division, Michigan Department of Natural Resources. 

EARLY GEOLOGICAL WORK 

The Geological Survey of Michigan was instituted 

by legislative act in 1838. Douglass Houghton, 

Michigan's first State Geologist, made his first report to the Legislature in 1838. The sequence of 

Carboniferous rock which he was able to identify 

was simply referred to as Upper Sandstones and 

Coal Measures. With the discovery of coal in 1835 

(Cohee and others, 1950) and the drilling of wells 

for brine to be used in the salt-making process, a 

considerable nomenclature soon began to ·develop 

for Carboniferous formations. A prominent and 

later State Geologist, Alexander Winchell, introduced in 1869 the term "Mississippian group" for 

the Carboniferous limestones of the Mississippi 

River Valley. Not until 1901, however, was the 

term Mississippian used to designate a part of Carboniferous rocks in Michigan. In 1901, Alfred Lane, 

another State Geologist, introduced the terms Pennsylvanian and Mississippian and referred both to 

the Carboniferous. But in Lane's 1904 report, both 

terms were dropped in favor of Carboniferous, only 

to reappear again in 1908. The term Carboniferous 

remained in general Survey usage until 1933. It 

was then considered obsolete and finally replac.ed by 

Mississippian and Pennsylvanian designations. 

Rocks now defined as Mississippian and Pennsylvanian have been variously subdivided and grouped 

by the Survey. Until 1901, most rock divisions now 

classified as Mississippian were classified as Devonian. After that date, the stratigraphic boundary between Devonian and Mississippian rocks became 

better defined and has remained virtually the same 

since then. The stratigraphic nomenclature applied 

to Mississippian and Pennsylvanian rocks from 1837 

to 1956 has been documented in chart form (Martin 

and Straight, 1956). 

MISSISSIPPIAN SYSTEM 

Early and Late Mississippian rocks are recognized 

in the Michigan basin. Early Mississippian rocks of 

Kinderhookian age include most of the· Bedford 

Shale, the Berea Sandstone, Sunbury Shale, and 

Coldwater Shale. The Coldwater Shale grades upward into the Marshall Sandstone without an apparent time break, and is considered to be of Osagian age. The remaining Mississippian rocks include the Michigan Formation and the overlying 

Bayport Limestone. The Michigan Formation, which 

overlies the Marshall Sandstone, ap·pears to grade 

upward from the Marshall without a break in sedimentation. The Bayport Limestone, the stratigraph-
0 

I I I I I I I I I I 

100 

I 

0 50 100 KILOMETERS 

EXPLANATION 

Upper Jurassic 

- Pennsylvanian 

~ ),®~! I Upper M~lssq,pian 

• Lower M~lssq,pian 

[j@@ Devonian 

- Upper Silurian 

MICHIGAN J3 

~ ~ 

43°'~~~~--~~~gg~~~~~~~~~~~~~~~~~~~~~ 

ERIE 

FIGURE !.-Distribution of Mississippian, Pennsylvanian, and remnant Jurassic bedrock in the Southern Peninsula of 

Michigan. Jurassic rocks overlie a part of the Pennsylvanian section and are limited to the basin interior. Outermost bedrock areas of the Southern Peninsula are Devonian except for a small area of Upper Silurian strata near the 

western end of Lake Erie. Distribution of bedrock units adapted from Kelley (1968). 
J4 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

TABLE !.-Mississippian nomenclature, 1947--64 

1956 

Martin and Straight 

Series Group Formation Series 

Maramec Bayport-Au Gres 

Limestone 

Osage Michigan 

Meramecian 

"Michigan Stray" 

Napoleon Sandstone 

Marshall Osagian 

Lower Marshall 

Sandstone 

Iowan Coldwater Shale 

~ Richmondville- 0 

0 Coldwater Sandstone ~ 

Q) Coldwater Limestone "0 

1:: "Red Rock" ~ 

Kinderhookian 

Sunbury 

Berea 

Bedford 

Ellsworth 

ically highest Mississippian rock identified in 

Michigan, likewise appears to lie conformably on 

the Michigan Formation. Both are classified as 

Meramecian or Late Mississippian. 

No break in sedimentation is apparent from Devonian into Mississip.pian time (Cohee and others, 

1951); thus the boundary between the two systems 

is obscure and not well defined lithologically. The 

boundary is believed to be within the basal fe.w feet 

of the Bedford Shale in eastern Michigan and the 

upper part of the Ellsworth Shale of western Michigan. An unconformity of considerable magnitude 

cuts across Mississippian formations in Michigan. 

Pennsylvanian sediments were deposited on this 

eroded surface and were in turn eroded. Table 1 

shows the nomenclature commonly applied to Mississippian rocks in Michigan from 1947 to present. 

Contact with underlying rocks.-In the Appalachian basin the Devonian-Mississippian boundary is 

in the basal few feet of the Bedford Shale. The Bedford Shale, Berea Sandstone, and Sunbury Shale of 

the Appalachian region can be projected into the 

1964 

Ells and others 

Group Formation Member 

Bayport Limestone 

"Triple Gypsum" Grand Rapids Michigan Brown Limestone 

"Stray Sandstone" 

Napoleon (Stray 

Sandstone Member) 

Marshall Marshall Sandstone 

Coldwater Shale Coldwater Lill)estone 

Coldwater Weir Sandstone 

"Red Rock" 

Sunbury Shale 

Berea Sandstone 

Bedford Shale 

Ellsworth Shale 

Michigan basin with considerable confidence, although these formations no longer connect with the 

Michigan bas.in. On this basis, and because of the 

lack of evidence to the contrary, the boundary in 

Michigan is also placed in the basal few f.eet of the 

Bedford (DeWitt, 1970, p. G 10). 

In the eastern sector of the Southern Peninsula, 

the Bedford Shale, the overlying Berea Sandstone, 

and the Sunbury Shale subcrop in a narrow band 

beneath the glacial drift and then offshore in Lake 

Huron. North of Saginaw Bay (fig. 1) they turn 

inland and again subcrop beneath glacial drift. No 

outcrops of these rocks are found in the Michigan 

basin. 

In eastern Michigan the gray Bedford Shale lies 

directly on the black, radioactive Antrim Shale o.f 

Devonian age (Chautauquan). The Antrim as defined in eastern Michigan is a facies of most of the 

greenish-gray Ellsworth Shale of western Michigan. 

The Bedford and the Berea and Sunbury formations 

above it thin in a westward direction and merge 

laterally into the upper approximately 30m (100ft) 

of the Ellsworth Shale. 
MICHIGAN J5 

Contact with overlying rocks.-In the central part 

of the basin, Mississippian rocks are overlain by 

sedimentary rocks of Pennsylvanian age which were 

deposited on an erosion surface. A sizable area of 

remnant Jurassic rock overlies a part of the Pennsylvanian (fig. 1). According to Cohee (1965), part 

of these Jurassic sedimentary rocks overlap onto 

Mississippian strata. Where not immediately overlain by Pennsylvanian or Jurassic rock, Mississippian strata are immediately overlain by Pleistocene 

glacial deposits. The extent of pre-Pennsylvanian 

erosion and the amount of sediments that may have 

been removed is unknown. Though now isolate~ 

within the Michigan basin, the continuation of certain Lower and Upper Mississippian rocks into 

adjacent regions outside the defined limits of the 

Michigan basin is well established (Cohee and 

others, 1951). 

To the northwest, in the western part of the 

Upper Peninsula, small outliers of Middle and Upper 

Ordovician, Middle Silurian, and Middle Devonian 

rocks are found at Limestone Mountain in Houghton County (Case and Robinson, 1915). Now completely surrounded by Precambrian rock, these outliers show that Paleozoic sediments extended far to 

the north of their present limits in the Michigan 

basin. Though Mississippian rocks are now found 

only in the Southern Peninsula, possibly they, too, 

once extended far north of their present lim~ts. 

Devonian and Mississippian strata were deposited 

in northeastern Illinois as shown by their preservation in fault blocks in the Des· Plaines Disturbance, 

an area north of Chicago, Ill. (Willm.an,. 1962). Except for such isolated locales, these· strata were 

largely truncated during erosion of the pre-Pennsylvanian surface. 

According to subsurface data, several hundred 

feet of Mississippian rocks were eroded from anticlines in the vicinity of Saginaw Bay before deposition of Pennsylvanian rocks. The erosional episodes 

before Pleistocene glaciation were no doubt complex. The preglacial drainage systems that carried 

sediments away from the central part of the Michigan basin are not well established in some areas as 

well control is lacking. In areas of abundant well 

control, pregla'Cial valleys lead into the valleys now 

occupied by the Great Lakes. 

Structural e v e n t s involving Carboniferous 

rocks.-Throughout most of the Michigan basin, 

anticlines trend in a northwest direction. Early 

recognition of this fact was useful in the development of the State's oil and gas industry. Oilfield 

studies show that most anticlines in Michigan were 

developed during several stages of folding beginning, in Middle Ordovician time and continuing, intermittently, into Mississippian. Structure mapping 

of numerous Mississippian formations and marker 

beds show similar folding. Michigan's stratigraphically youngest Mississippian formation, the Bayport Limestone, varies in thickness because of the 

erosional unconformity which separates it from the 

overlying Pennsylvanian rock. Presumably the Bayport Limestone, and other Mississipp·ian strata 

which may have been deposited above it but later 

eroded, was also folded. 

Faults have been observed in Pennsylvanian rocks 

and must also occur in Mississippian rocks. Subsurface investigations show that faulting has taken 

place along the fl.anks of such structures as the 

Howell-Northville anticlines and others included in 

the Washtenaw anticlinorium (Ells, 1969) ; Fractures, brecciation, and steep dips which may suggest faulting, have been observed in Ordovician, 

Silurian, and Devonian rocks, but have not been reported in Mississippian sediments associated with 

thes·e structures. 

Along the Howell anticline near the Howell gas 

storage field, more than 305 m (1,000 ft) o.f structural movement has ta~en place .. Over the crest and 

higher part of the structure, in certain areas, the 

Berea Sandstone is eroded and found im.mediately 

beneath the glacial drift (Ells, 1969). At the northern end of the structure, Pennsylvanian strata are 

found on both sides of the feature, and it is likely 

that they, too, were folded and later eroded. The 

Howell anticline is the most prominent structure 

in this area of en echelon folds. Recent studies 

(Wanless and Shideler, 1975) ·suggest that at the 

beginning of Morrow time, the anticlinal areas stood 

above the surrounding depositional plain as a 

monadnock several hundred feet high, but was 

buried by the ·end of Morrow time. 

Up·per Silurian (Cayugan) salt beds have been 

dissolved in places. along the west edge of the Howell 

anticline. Solution of salt and subsidence of certain 

formations appear to have taken place mainly during Devonian time. Solution channels are probably 

related to fractures associated with the fault zone. 

Some evidence exists that Mississippian rocks as 

high in the sequence as the Sunbury Shale were 

affected in areas of greater subsidence. Contours on 

the top of this formation show closed depressions 

over areas of probable salt removal. 

Igneous and metamorphic rocks.-There is no 

evidence in the Michigan basin of igneous actiivty 

during Mississippian and Pennsylvanian time. A 
J6 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

45°'4---------JL+-~~~~--+-----------r-----~--

r 1 1 1 1 

0 I I I I I 

100 MILES 

I 

0 50 100 KILOMETERS 

ERIE 

FIGURE 2.-The northwest-trending Howell anticline is one of the most prominent structures associated with the 

Washtenaw anticlinorium, a region containing several similar-trending structural features that plunge basinward. See 

figure 1 for areal bedrock geology associated with this feature. Counties having outcrops of Mississippian or Pennsylvanian rock are outlined. 
MICHIGAN J7 

bentonite zone has been noted in Middle Devonian 

rocks in the basin (Baltrusaitis, 1974) but no ash 

beds have been found in Mississippian or Pennsylvanian rocks. Rocks of both systems show no signs 

of alteration that might be related to metamorphism. 

MISSISSIPPIAN FORMATIONS 

As mentioned earlier, no break in sedimentation 

is apparent from Late Devonian into Mississippian 

time. The boundary between the two systems is 

within the basal part of the Bedford Shale which 

immediately overlies the Antrim Shale of Devonian 

age (Chautauquan) in eastern Michigan and the 

upper part of its correlative, the Ellsworth Shale of 

· western Michigan. 

Bedford Shale.-The Bedford Shale and the overlying Berea Sandstone were first identified in Michigan from a well in southeastern Michigan (Rominger, 1876). These form,ations subcrop beneath the 

glacial drift and have not been identified at the surface in Michigan. They are correlated with the Bedford, Berea, and Sunbury of Ohio on the basis of 

lithology and stratigraphic position. They are not 

continuous from Michigan into Ohio, having been 

eroded from. the Findlay arch in northwestern Ohio 

and in Ontario, Canada. The Bedford is a silty, gray 

shale containing numerous stringers of Berea-type 

sandstone. The upper part of the Berea contains 

Bedford-type shale stringers; thus the Bedford and 

Berea are frequently treated as a single formation. 

Gam.ma ray-neutron logs show these features but 

also show a definite separation between the two 

formations. The Bedford is as much as 61 m (200 

ft) thick in eastern Michigan but thins westward 

and merges into the upper part of the Ellsworth 

Shale. 

Berea Sandstone.-The Berea Sandstone in Michigan has been divided into three lithologic units 

(Cohee and others, 1951). The lower unit is light 

gray, fine grained, dolomitic sandstone which is 

silty and shaly, cemented with s.ilica and dolomite, 

and is micaceous and pyritic. The middle unit is 

friable, fine grained sandstone composed of angular 

quartz grains. The upper unit is lithologically similar to the lower unit but is less shaly and pyritic.· 

The Berea is thickest around Saginaw Bay. Like the 

underlying Bedford Shale, the Berea thins westward, and about mid-basin it merges into the upper 

part of the Ell:sworth Shale. The thin facies found 

in the upper part of the Ellsworth is sometimes 

referred to as "Berea." 

The Bedford Shale and Berea Sandstone o.f northea·stern Ohio and northwestern Pennsylvania are 

associated with deltaic deposition (DeWitt, 1970). 

As the same formations are correlated with similar 

rocks occupying the same stratigraphic position in 

Michigan, the inference is that they are also a part 

of the same deltaic system. Acco·rding to Cohee 

(1965), the clastic materials making up the Bedford 

and Berea formations came from Onta.rio and the 

Canadian shield and were carried into the eastern 

side of the Michigan basin as deltaic deposits. The 

name commonly applied to the part of the Southern 

Peninsula east of Saginaw Bay, where these rocks 

are thickest and best formed, is "the thumb." Accordingly, Cohee named the Bedford-Berea deltaic 

deposits the Thumb Delta. The Sunbury Shale, 

normally not considered a part of the deltaic deposits, lies immediately above the Berea Sandstone. 

Sunbury Shale.-The Sunbury Shale is more 

widespread within the basin and is thickest in the 

same general area of the basin as the Bedford and 

Berea formations. More than 30m (100ft) thick in 

the Saginaw Bay region near Lake Huron, the Sunbury is a black to dark-brown shale lithologically 

similar to the Antrim of Devonian age. First identified by Lane in 1909 from well cuttings, it is known 

in Michigan only from subsurface studies. It extends over most of the Southern Peninsula, but thins 

and grades into gray and greenish-gray shales in 

the top part of the Ellsworth Shale in places in the 

western and southwestern part of the State. 

Coldwater Shale.-The Coldwater Shale is one of 

the most widespread and thickest of Mississippian 

formations. Predominantly a gray to· bluish-gray 

shale, it is about 396 m (1,300 ft) thick in the 

central part of the basin. Named by Lane in 1895 

from small exposures along the Coldwater River 

near Coldwater, Mich., other small outcrop's are 

found at places in Branch and Hillsdale Counties 

and along the shores of Lake Huron in Huron and 

Sanilac Counties. The Coldwater Shale extends 

beneath the drift into no·rthern Indiana and northwestern Ohio. It is correlated with the Borden 

Group of Indiana and Illinois and the Cuyahoga 

Group of Ohio. 

In the western part of the basin, the Coldwater 

Shale is similar to upper parts of the underlying 

Ellsw;orth Shale. The two formations are separated 

by a useful· marker bed referred to as Coldwater 

"Red Rock." From 3-6 m (10-20 ft) thick, it consists of red limestone, red shale, dolomite, and 

glauconitic dolomite. It can be traced eastward above 

the black Sunbury Shale but does not extend everywhere within the eastern part o.f the basin. The 

Goldwater "Red Rock" may be equivalent to the 
JS THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Rockford Limestone of Indiana and Illinois (Cohee 

and others, 1951). But according to Lineback (1970, 

p. 35) the Rockford Limestone is not found in the 

Michigan basin. 

Several facies have been identified within the 

Coldwater Shale sequence but cannot be traced 

acl'loss the basin. In an area of western Michigan, 

an argillaceous dolomite zone com.monly referred 

to as the "Coldwater Lime" or "Speckled Dolomite" 

is about 91 m (300 ft) above the base of the shale 

(Hale, 1941). This zone grades eastward into shale. 

On the eastern side of the basin several sandstone 

beds are found in the upper part of the Coldwater 

Shale and may correlate with scattered surface exposures near Richmondville in Sanilac County. A 

silty sandstone interval near the base has been 

called the Weir Sandstone, but like most of these 

lenticular sandstone beds, it does not ·extend for any 

great distance in the subsurface. The small exposures .of Coldwater Shale are not representative of 

the sequence as known in the subsurface. In the 

subsurface the Coldwater grades upward into _the 

Marshall Sandstone, thus making the contact between the two formations difficult to define in most 

areas. 

Marshall Sandstone.-The Marshall Sandstone, 

which overlies the Coldwater Shale, is frequently 

divided into two members: the lower Marshall and 

the Napoleon Sandstone. The Marshall Sandstone 

was named by Winchell in 1861 from outcrops 

around Marshall, Calhoun County, Mich. At an earlier date ( 1838), Douglass Houghton, Michigan's 

first State Geologist, had named the upper part of 

the Marshall, the Napoleon Sandstone, from exposures around Napoleon, Jackson County, Mich. In 

1900, Lane designated these rocks as the upper 

Marshall Sandstone. The Napoleon persists as a 

member bed, though there is little need for such 

a designation. 

Because of the indefinite contact between the 

Marshall and underlying Coldwater Shale in most 

parts of the basin, thickness values assigned to the 

entire Marshall section range. from 46 to 122 m 

( 150 to 400 ft) . Electric-log studies sho·w better 

definition of the Goldwater Shale-Marshall Sandstone contact than ordinary well-cutting investigations. The Marshall also has silty shale beds that can 

be best traced by use of electric logs of the gammaray type. 

The Marshall Sandstone also has affinities with 

the overlying Michigan Formation. The basal part 

of the Michigan Formation intergrades with the 

upper Marshall, particularly in the central part of 

the basin. A sandstone, most frequently referred to 

as the "Stray Sandstone" and assigned to the basal 

part of the Michigan Formation, overlies and interfingers with the lithologically similar sandstone, 

the Marshall. The boundary between the two sandstones is not easily determined. In the past the 

"Stray," which produces gas, has been compared 

with "shoestring sands," or sandbars, such as those 

in Oklahoma and Kansas (Ball and others., 1941). 

Modern logging techniques and more abundant well 

control suggests a variable but blanket-type deposit 

rather than isolated, linear sandbars. The underlying Marshall, which also produces gas in a few 

fields, is a blanket-type sandstone body. The socalled "Stray" can be traced into the Napoleon Sandstone of the outcrop area. Evidently there was little, 

if any, break in deposition from Marshall time into 

Michigan Formation time. 

The Marshall Sandstone is confined to the Southern Peninsula and apparently was removed from a 

much larger area by pre-Pleistocene erosion. According to Cohee and others (1951), the Marshall 

Sandstone overlying the Coldwater Shale is probably the time equivalent to the upper p·art of the 

Borden Group (Osage) of northern and southern 

Indiana. 

Mi;chigan Formation.-The Michigan Formation, 

now cut off from correlative rocks in other States, 

consists of gray to dark-gray and greenish-gray 

shale, thin beds of limestone, dolomite, sandstone, 

and anhydrite and gypsum. Originally called Michigan Salt Group by Winchell (1861), the formation . 

was described from exposures at Grand Rapids, 

Kent County, and from exposures along the shore 

of Tawas Bay on the west side of Saginaw Bay. Although brines are found in the porous parts of the 

formation, no bedded halite has been found in the 

thousands of wells which have now penetrated the 

section. The name was eventually changed to Michigan Formation. 

As previously noted, the basal sandstone of the 

Michigan Formation intergrades with the upper 

Marshall in the· central basin. Some geologists have 

described these basal sandstones as reworked Marshall (Newcombe, 1933) thus implying an erosion 

surface between the "Stray" sandstone and the 

upper Marshall, or Napoleon Sandstone. The Michigan Formation, now confined to the central part of 

the basin and .cut off from correlative strata in adjacent basins, is believed to be lower Meramac in 

age. The thickness of this formation is about 183 m 

(600ft). 
MICHIGAN J9 

Facies changes are evident within the Michigan 

Formation. Depositional pinchout of shale beds or 

merging of shale beds into sandstones is common. 

However, several key beds show widespread continuity and are useful in mapping subsurface structures. The stratigraphically lowest marker bed, referred to as "brown lime" or "brown dolomite.,'' is 

about 4.5 m (15 ft) thick and is found from 30 to 

46 m (100 to 150 ft) above the "Stray Sandstone" 

in the central basin areas. Another marker, referred 

to as "Triple Gyp zone" (Wolcott, unpub. data, 

1948) consists of three anhydrite beds separated 

by thin shale stringers. This zone, about 9 m (30 ft) 

thick and about 12 m ( 40 ft) above the "brown 

lime," is especially evident in electric logs of the 

gamma ray .. neutron type. Other anhydrite beds may 

be traced for considerable distances. 

Bayport Limestone.-The Bayport Limestone is 

the youngest Mississippian rock identified in Michigan. Originally called Point Au Gres Limestone from 

small outcrops on the west shore o.f Saginaw Bay 

(Douglass, 1841), better exposures were found 

around Bayport, Huron County, Mich., so the name 

was changed to Bayport Limestone in 1899 by Lane. 

Scattered outcrops are found in several areas of the 

basin but the best exposures are found in quarries 

in Eaton, Huron, and Arenac Counties. 

The Bayport is light buff to brown and contains 

chert, frequently in spherical-shaped forms along 

certain bedding planes. The basal part may be 

arenaceous or may contain thin sandstone beds in 

some regions. The thickness is variable and generally less than 30 m (100 ft). According to thickness maps (Cohee and others, 1951), the Bayport 

has been completely removed by pre-Pennsylvanian 

erosion from several areas of the central part of the 

basin. 

The Bayport is considered to be conformable on 

the Michigan Formation and is treated as a formation of the Grand Rapids Group. The fauna indicates correlation of the Bayport Limestone with the 

upper p·art of the St. Louis Limestone· and the Ste. 

Genevieve Limestone of the Mississippi Valley 

(Newcom.be, 1933). Newcombe also states that the 

beds can be compared approximately with the Maxville Limestone of Ohio. The Bayport is now isolated and cut off from. its correlative sections in 

adjacent basins. 

PENNSYLVANIAN SYSTEM 

Pennsylvanian rocks cover an area of approximately 29,784 km2 (11,500 sq mi) in the central 

basin (fig. 1). The sequence has been variously divided by different geologists since the coal-bearing 

measures were first discovered near Jackson, Jackson County, in 1835. The most extensive nomenclature was formulated by Lane in 1901, 1905, and 

1908 when Michigan coal was an important resource. 

Studies were made by Kelly (1933, 1936) in which 

the cyclothemic nature of the strata was recognized. 

A more recent evaluation of Michigan's Pennsylvanian sequence wa!s made by Wanless and Shideler 

(1975) who derived most of the thickness and 

lithology data from logs o.f oil-well borings. The 

nomenclature used in 1861 and at various times 

through 1975 is shown in table 2. Because Michigan 

coal measures have little economic imp,ort at this 

time, and records of wells that penetrate these rocks 

are not definitive in detail, Pennsylvanian rocks are 

commonly divided into a Saginaw Formation (Pottsville Series) and an overlying Grand River Formation (Conemaugh Series). The Parma Sandstone, 

long considered the basal formation of the Pennsylvanian section, cannot be traced throughout the 

basin. Because of its very restricted occurrence, it 

is treated as an unnamed unit of the Saginaw 

Formation. 

Outcrops of Pennsylvanian strata are extremely 

limited in the Michigan basin because of the thick 

cover of Pleistocene glacial drift. A concentration 

of outcrops is found along the Grand River near the 

town of Grand Ledge, Eaton County, and along the 

Grand River valley in the City of Jackson, Jackson 

County. Most of the knowledge of Michigans' Pennsylvanian section has come from study of coal borings (Andrews and Huddle, 1948; 'Cohee and others, 

1950), from data gathered from c·oal mines and 

open pits when they were in operation, and from a 

large number of oil-well borings. These studies concentrated on the coal resource. 

Subsurface studies show erosional unc·onformities 

at the top and base of the Pennsylvanian section, so 

the thickness values vary over different parts of the 

basin. Thicknesses range from as much as 91 to 152 

m (300 to 500 ft) in the Saginaw Bay region to 

more than 213m (700ft) farther west in the basin 

(Cohee and others, 1951). Thickness determinations 

are complicated by similar lithologies of sedimentary 

rocks of Jurassic age which overlie part of the 

Pennsylvanian section and by the Michigian Formation-Bayport Limestone of Mississippian age 

which underlies the section·. 
JlO THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

PENNSYLVANIAN FORMATIONS 

The most definitive stratigraphic studie·s of Michigan's Pennsylvanian system are probably those by 

Kelly (1930, 1931, 1933, 1936). Kelly recognized the 

cyclical nature of the many strata and the unconformities which separate many of them. He referred 

to the coal-bearing interval as the Saginaw Group 

and presented evidence that the Verne Limestone 

was a comparatively persistent member and a convenient place to divide the Saginaw Group into preand post-Verne cyclical formations (table 2). Occasionally the Verne Limestone can be recognized in 

well cuttings obtained by cable-tool drilling, but in 

general pre-Verne and post-Verne cyclical formations are difficult to correlate for any distance. 

Therefore the Saginaw is treated as a single formation. The Parma Sandstone, long considered the 

basal formation of the Pennsylvanian, is now treated 

as an unnamed unit of the Saginaw Formation because of its restricted occurrence and doubtful correlation from region to region. The uppermost division of the Pennsylvanian referred to by Kelly 

(1936) as the Grand River Group, is mainly a sandstone interval and is treated as a single formation. 

Saginaw Formation.-The aggregate thickness of 

Pennsylvanian rocks is probably 213-229 m (700-

750 ft). Most o.f this thickness is assigned to the 

Saginaw Formation. The Saginaw is composed of 

material of freshwater, brackish water, and marine 

origin. It consists of sandstones, shales, coal, and 

limestones. According to Kelly (1936, p. 165), and 

others, individual strata vary in charact~r and 

thickness within relatively short distances. Numerous unconformities have disrupted cyclothem sequences and in places the complete sequence appears 

to have been removed by erosion. Co·al beds are thin 

and discontinuous. Recent investigations (Kalliokoski and Welch, 1976), using primarily water-well 

and oil-well records, show that very few coal occurrences are outside of the six-county area surrounding the tip of Saginaw Bay. This six-county region 

represents less than half of the areal distribution of 

Pennsylvanian rocks shown in figure 1. 

TABLE 2.-Pennsylvanian nomenclature in Michigan, 1861-1975 

1861 1876 1895 1901 1905 1908 1909 1912 1931 1933 

Winchell Rominger Lane Lane Cooper Cooper Lane Smith Newcombe Kelly 

Wood- Q; 

"Red Beds" 

"Red Ionia 

Wood- Wood- Woodville Woodville ville Wood- Beds" .~ Q. Sandstone a: :l 

ville ville absent in absent in Ionia ville Wood- , e Eaton 

Bay County Tuscola County sug- ville E~ Sandstone 

gested ~ Woodville 

Sandstone 

Reese Coal 

Salzburg Rider Unionville Coal 

Salzburg Coal Salzburg Rider 

Upper Rider Upper Rider Salzburg Coal Post-Verne 

en Lower Verne a.. Cyclical w Coal Upper Verne Coal Upper 1 Rider ::::> ~ormations a: 0 

Jack- w Upper Verne ~ Lower Verne Rider 

~ Lower Verne Rider a: en ~ Coal Coal son Coal z measures measures Coal ~ Middle Rider ~ Lower Verne Coal a Lower Verne Coal Saginaw Saginaw Saginaw 

~ Verne 

Group ~ Saginaw Coal en Middle Rider ~ Middle Rider z ~ ~ Pre-Verne < Saginaw Coal Saginaw ~oa I < en Lower Aider en Cyclical Lower Aider Lower Aider Lower Coal Formations 

Lower Coal Lower Coal 

Bangor Rider Bangor Rider 

Bangor Coal Bangor Coal 

Parma 

doubtfully Parma probably 

Parma Part:na Parma Parma represented in Parma Parma Parma restricted to 

Tuscola County southern area 
MICHIGAN J11 

Grand River Formation.-The Saginaw Formation is considered to be overlain in most areas by 

sandstones referred to as the Grand River Formation. Grand River sandstones, thought of as a group, 

include in ascending order the Woodville (Winchell, 

1861), Eaton (Kelly, 1936), and Ionia (Lane, 1909). 

These sandstones are very similar. Little evidence 

exists to show that they represent a vertical succession of strata as used in the group sense. Laterally, they do not yield to precise correlation. 

The Grand River Formation consists predominantly of coarse sandstones with conglomeratic beds 

near the base. The sandstones are chie·fly quartz 

cemented by siliceous or ferruginous material. Small 

amounts o.f feldspar and heavy minerals such as 

zircon and tourmaline are present. The formation 

is as much as 30 m (100 ft) thick. Red and brown 

colors and in some places purplish coloration are 

charactedstic of the beds. According to Kelly .(1936, 

p. 210) the various characteristics o.f the Grand 

River sandstones indicate that it was of freshwate·r 

origin, that much of the formation was due to river 

TABLE 2.-Continued 

1964 1975 

Ells and others Wanless and Shideler 

.. Interval Formation Named Unit Q) c: Ionia Sandstone 

~ ·~ Eaton 

-g e Sandstone c Grand River 

~af Woodville Formation 

Sandstone 

Verne 

Limestone 

Member 

z 

0 B 

~ :E 

a: 

0 Verne Saginaw Verne u.. 

~ Limestone Formation Coal 

z 

~ (/) 

A Saginaw 

Coal 

Parma 

Sandstone 

Member 

deposition, and that some of the beds are channel 

sandstones. 

Contact with underlying rocks.-The basin was 

uplifted and eroded in Late Mis-sissippian time. The 

Coldwater Shale (Kinderhook) and Marshall Sandstone (Osage ) of Early Mississippian age, and the 

Michigan Formation and Bayport Limestone 

(Meramac) of Late Mississippian age were eroded 

from some of the more prominent anticlinal folds. 

In most areas, Pennsylvanian strata lie on the 

eroded surface of the Michigan Formation or the 

Bayport Limestone. In areas where these Late Mississippian rocks were completely removed, Pennsylvanian strata may lie directly on the eroded surface of the Marshall Sandstone. According to Cohee 

and others ( 1951) the last folding took place after 

deposition of Pennsylvanian sediments had ceased. 

A buff limestone in the lower part of the Saginaw 

Formation in the central part of the basin (Isabella 

County) is said to be well enough defined on electric logs of that area to indicate that structure of 

the Pennsylvanian rocks in general conforms to the 

underlying Mississippian strata (Cohee and others, 

1951). 

The Howell anticline, one of the major structures 

in the Michigan basin, is a complex, faulted, structural feature which plunges to the northwest (fig. 

2). It was elevated and the crest stripped of Mississippian strata down to the Berea Sandstone 

(Kinderhook) in the Howell region, Livingston 

County (Ells, 1969). Along the southeasteriy strike 

of the structure., successively older strata subcrop 

beneath Pleistocene glacial drift. Pennsylvanian 

rocks are not recognized over the crestal part of the 

structure except at its northern terminus in Livingston County. Presumably Pennsylvanian rocks 

extended over at least most of the anticlinal area 

but were removed by erosion. Acc-ording to Wanless 

and Shideler (1975, p. 64), the Coldwater Shale of 

Early Mississippian age underlies the central part of 

the Howell structure. They state that this elevated 

area app_arently stood above the depositional plain 

as a monadnock several hundred feet high and was 

not buried until about 122 m (400 ft) of Lower 

Pennsylvanian sediment (table 2, interval A) had 

accumulated around it. By the end of interval A 

time the monadnock was buried. 

Michigan's Pennsylvanian rocks are restricted to 

the interior of the basin and isolated from the coal 

basins of Ohio and Illinois. Because of post-Pennsylvanian erosion, the total thickness and original 

areal distribution of these rocks within the basin is 

unknown. An extensive study was made by Kelly 
J12 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

(1936, pp 172-76) of Michigan's Pennsylvanian 

marine fauna, most of which is found in the Verne 

Limestone. He concluded that the embayment in 

which the Verne marine member was deposited 

originally extended from at least the vicinity of 

Bay City southwestward in a direction approximating the long axis of Saginaw Bay (fig. 1). The extension of the embayment outside the State of Michigan was said to be toward Indiana, Illinois, and 

Iowa rather than toward Ohio. According to Wanless and Shideler (1975, p. 68), during the time that 

the Verne Limestone was. being deposited in the 

Michigan ·basin, the Seville of northern Illinois and 

the Mercer of northern Ohio were being deposited. 

The exact positions. of the seaways are not known. 

Pennsylvanian clays are found in solution cavities 

in Silurian strata near Kankakee and Joilet in 

northeastern Illinois (Willman, 1962, p. 63). The 

presence of these clays would seem to support the 

concept of an ·embayment which once extended 

northeastward across the present Kankakee arch 

and into the Michigan basin. 

Contact with overlying rocks.-A sizable area of 

pre-Pleistocene but post-Pennsylvanian sediments 

immediately overlies part of the beveled Pennsylvanian surface. Largely confined to the western and 

northern Pennsylvanian subcrop region (fig. 1), 

these sediments consist of poorly consolidated red 

mudstones, greenish-gray mudstones, .sandstones, 

and gypsum, frequently of the selenite variety. 

These rocks app~rently do not crop out anywhere in 

the Michigan basin so are known only from subsurface studies. Once classified as "Permo~Carboniferous Red Beds" (Newcombe, 1931) and then as 

Pennsylvanian (Kelly, 1936), they are now classified 

as Late Jurassic (Kimmeridgian) age (A. T. Cross, 

oral commun., 1964) on the basis of spores collected 

from well cuttings. A formal nom.enclature has not 

been established for these Jurassic sedimentary 

rocks; they are simply referred to as "red beds." 

The red beds contain spores shown by Cross (1966) 

to be similar to those in the Fort Dodge Gypsum of 

Iowa.·· 

The· original extent and thickness of the "red 

beds" in the Michigan basin is unknown. Though 

mainly overlying Pennsylvanian strata, red-bed 

sediments directly ov·erlie the eroded surface of the 

Michigan Formation in some peripheral areas, and 

are thus confused with these Mississippian strata. 

Red mudstones and gypsum have also been included 

in the upper part of the Pennsylvanian section in 

the. subsurface (Kelly, 1936; Wanless and Shidler, 

1975, pp 68-69). The base or contact of these 

Jurassic sedimentary rocks with underlying Mississippian and Pennsylvanian rocks is not everywhere 

easily identified. Rocks assigned to the "red bed" 

interval are poorly consolidated and frequently subject to caving and lost circulation problems in drilling. Because of these conditions, well cuttings are 

few and do not necessarily reflect an accurate vertical succession of strata. They may include a mixture 

of Mississippian or Pennsylvanian sediments. 

A study by Cohee and others (1951) of well logs 

and samples. in the area of "red beds" showed much 

variation in thickness and an uneven distribution. 

This suggested that "red bed" sediments were deposited in topographic depressions, possibly under 

conditions of subaerial erosion, after deposition of 

Pennsylvanian rocks in Michigan had ceased. Hereported thicknesses of 91-122 m (300--400 ft) in some 

subcrop sectors. Cohee and others (1951) also r~ 

ported that investigations for water supplies in certain areas in Michigan showed that "red beds" were 

limited to topographic lows in the bedrock surface. 

There is some indication that the source of information was unintentionally misquoted and that "red 

beds" are confined to topographic highs rather than 

lows. 

Except for small, widely scattered outcrops of 

various age assignments, the bedrock surface of the 

Michigan basin is covered by Pleistocene glacial 

drift. The glacial drift directly overlies Pennsylvanian rocks except for those are31s directly overlain 

by remnant Jurassic sedimentary rocks which, in 

turn, are also covered. 

MISSISSIPPIAN-PENNSYLVANIAN 

ENVIRONMENT OF DEPOSITION 

All of Michigan's Mississip·pian rocks were· accumulated in a marine environment. Largely shales 

and sandstones, they are about 914 m (3,000 ft) 

thick. At different times, sediments appear to have 

been supplied from eastern, western, and northern 

sources, causing intertonguing of sedim·ents or 

lateral blending of them. No obvious break in sedimentation is apparent from Late Devonian ( Chautauquan) time through Late Mississippian (Meramecian) time, although Middle Mississippian rocks 

have not been identified. Mississippian :strata were 

apparently subject to a variety of depositional environments while they were accumulating in the 

basin. 

On the eastern side of the Michigan basin, the 

Bedford Shale and overlying Berea Sandstone are 

. invariably interpreted as deltaic deposi.ts which 
MICHIGAN J13 

merge westward into the Ellsworth Shale. The Ellsworth Shale was probably derived from a western 

source. The Sunbury Shale, immediately overlying 

the Berea Sandstone, is dark brown to black and is 

thickest in eastern Michigan. This shale, of either 

shallow ·Or deep-water deposition, represents a different depositional environment from. that of the 

underlying Berea and Bedford forma;tions. The thinning of the Sunbury formation in a general east to 

west direction across the basin, provides. some evidence that the unit represents a transgressive-regressive depos.itional cycle within Michigan. 

The Coldwater Shale, about 396m (1,300 ft) thick 

in the central part of the basin, contains thin lenticular siltstones and sandstones, thin limestones, and 

thin beds of limonite nodules. Several lateral facies 

within the sequence· suggest probable transgressiveregressive episodes. Over much of the basin the 

upper part of the Coldwater is characterized by an 

increasing number of thin siltstone or sandstone 

beds separated by thin shale beds. The alternating 

nature of these beds foreshadows the deposition of 

the Marshall Sandstone. 

The Marshall Sandstone, which grades up·ward 

from the Coldwater Shale fo·rmation, also contains 

Coldwater-type shales in parts of the basin. Shales 

and silty shales pinch out within the sandstone sequence or merge with sandstone strata. Some beds 

within the Marshall contain shell coquinas which 

may be indicative· of shallow-water or shoreline 

deposition. In ~som·e areas where the Marshall grades 

into the overlying Michigan Formation, a thin 

sandy dolomite or limestone is found at the top· of 

the Marshall. 

Following deposition of the Marshall Sandstone, 

the basin continued to receive clastic material but 

became mor·e restricted. During this phase, sediments now assigned to the Michigan Formation 

were deposited. The formation, about 183 m ( 600 

ft) thick is made up of shale beds, anhydrite beds, 

and lesser numbers of sandstone, dolomite, and 

limestone beds. Several of the anhydrite· beds and 

at least one of the limestone beds within the formation hav·e widespread lateral continuity within the 

basin. The youngest Mississippian unit, the Bayport 

Limestone, is. conformable with the underlying 

Michigan Formation and represents a return to 

more normal marine conditions. The Bayport is very 

irregular in thickness and distribution becaus·e of 

erosion during post-Bayport pre-Pennsylvanian uplift near the close of Mississippian time. 

Pennsylvanian rocks in the Michigan basin are 

primary clastics. deposited upon an eroded surface 

of Mississippian rocks. Sedim·ents were deposited 

under deltaic and swamp conditions, some of which 

resulted in thin coal beds. Cyclic deposition is evident within the coal-bearing interval, and marine 

inundations are evident as shown by fossiliferous 

limestones. Unconformities which cut out parts of 

cyclothems ap·pear to be frequent. Channel sandstones which suggest deposition by river systems 

have been identified. Red and green :shales and 

gypsum have been identified as Pennsylvanian in 

parts of the basin. But as similar rock assemblages 

are found in the Michigan Formation which underlies p·arts of the Pennsylvanian sequence, the age 

of these rocks may be misidentified. The upper nonc.oal bearing part of the Pennsylvanian is mainly 

sandstone. The source area f.or these and the underlying clastics is consider·ed to be eastern and northern highlands. 

The original thickness and extent of Pennsylvanian rocks once covering Michigan is unknown. 

The Verne Limestone, which is carbonaceous and 

has an abundant marine fauna, has been correlated 

with the Seville Limestone of Illinois and a part 

of the Me·rcer Formation of Ohio. A seaway of unknown dimensions undoubtably connected the Michigan, Illinois, and Appalachian. basins. Following 

deposition of Pennsylvanian rocks in the Michigan 

basin, the region was uplifted and eroded. Erosion 

was severe and the Pennsylvanian surface was 

heavily dissected by stream valleys. The thickest 

sections of Pennsylvanian rock with a maximum 

of about 229 m (750 ft) are found in the central 

part of the basin. The entire Pennsylvanian section 

is now confined to the interior of the basin and isolated from correlative rocks in other depositional 

basins. A remnant section of Jurassic-age rocks 

overlies a part of the Pennsylvanian sequence. 

These rocks ar·e overlain by Pleistocene glacial drift. 

The presence of Mesozoic rocks in Michigan is 

of special interest. Now remote from other Mesozoic 

strata, these remnant Late Jurassic sedimentary 

rocks overlie a part of the eroded Pennsylvanian 

surfac-e and overlap onto parts of the e·roded Mississippian rocks. In turn, they· were app·arently 

eroded before Pleistocene glaciation· and burial 

beneath Pleistocene glacial deposits. Formerly 

classfied as "Permo-carboniferous Red Beds" and 

later as Pennsylvanian "Red Beds," they have now 

been identified on the basis of palynologic evidence. 

The lithology of these red beds, possibly as much as 

122m (400ft) thick, consists of poorly consolidated 

red and green clays and shales, sandstones, and some 

gypsum .. The stratigraphic order of these different 
J14 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

lithologi·es is uncertain. The lower boundary is also 

uncertain because similar lithologies have been, or 

are, included in underlying Mississippian or Pennsylvanian formations. Palynologic studies do confirm their age assignment at least down to the controversial lower boundary. Whether these sediments 

accumulated in depressions as valley fill or in playa 

lakes as suggested by Cohee (1965), or are confined to Pennsylvanian topographic highs, or covered a much larger part of the Michigan basin, 

awaits further r·esearch. 

ECONOMIC PRODUCTS 

Valuable resources have been extracted from 

Michigan's Mississippian and Pennsylvanian rocks 

for many year.s. Though no metallic ores are found 

in either system, certain Mississippian formations 

have supplied shales suitable for use in cement and 

brick and tHe man ufaeture; :sandstones and limestones for construction and aggregate us·e; natural 

saline brines used in salt and chemical manufacture ; 

and gypsum for use in various gypsum-based products. Mississippian rocks, primarily the .sandstones, 

have also produced significant volumes of natural 

gas and petr.oleum. In certain areas of the State, 

Mississippian sandstones al1so are valuable and important sources of freshwater. Michigan's Pennsyivanian rocks, have fewer usable mineral resources, but were once important as a source of coal. 

In the early days of salt production (1860) from 

the evaporation of brines, brines from basal Pennsylvanian formations were us·ed along with those 

from Upper Mississippian sandstones. The Pennsylvanian brines were subsequently abandoned in 

favor of the more concentrated salines of the underlying Mississippian sandstones. Pennsylvanian rocks 

are also the source of shales for brick and tile manufacture. In years past, sandstones were quarried at 

a few locales for building stone. In certain areas of 

the State, the upper part of the Pennsylvanian section serves as an important source of freshwater. 

The economic products currently extracted from 

Carboniferous rocks and other informative data are 

summarized. 2 

Sandstones .-Mississippian sandstones (Napoleon 

Sandstone member of the Marshall Sandstone) are 

quarried at. three locations near Napoleon, Jackson 

County, Mich. The product is rough and dressed 

dimension stone which is used in various construell Information on economic products other than petroleum and natural 

gas supplied by Milton Gere, Economic Geologist, Geological Survey Division, Michigan Department of Natural Resources. 

tion projects. 'Curr.ent production has. averaged 

about 5,000 short tons ( 4,500 t) per year over the 

past 3 years. Historically, a number of quarries 

have been operated in the past throughout the outcrop area of the Marshall-Napoleon Sandstone in 

the southern part of the State. Small amounts of 

Pennsylvanian sandstone (Ionia Sandstone-Grand 

River Formation) were once quarried at Ionia, Ionia 

County, and possibly at other areas. 

Shale.-Pennsylvanian shales from the Saginaw 

Formation are quarried in three locations. The shale 

mined in Clinton and Eaton County is ground and 

used in the manufacture of vitrified field and sewer 

tile. That produced in Shiawassee County is ground 

and used to manufacture bricks. The annual production from these operations in both 1974 and 1975 

amounted to 100,000 short tons (90,000 t). In the 

past, Pennsylvanian shales were also quarried in 

Ingham and Jackson counties for use in brick and 

tile manufacturing. 

Limestones.-Mississippian Bayport Limestone 

has been quarried for many years in several parts 

of the State. Currently seven quarries are in operation. From. quarries in Arenae, Eaton, Huron, 

and Jackson Counties, limestone production in 1974, 

1975 and 1976 ranged from more than 1.1 to nearly 

1.4 million short tons ( 1.26 million t) . Most of the 

limestone is used as construction aggregate but 

some of high purity is us.ed in the beet-sugar refining process. 

Gypsum.-Gypsum beds of the Michigan Formation (Late Mississippian) have been mined for more 

than 100 years. Presently five gypsum mines are in 

operation; two shallow underground mines in Kent 

County and three open-pit operations in Iosco 

County. Annual production figures have been kept 

since 1868. Before 1868, 146,528 short tons (131,875 

t) were mined. Total gypsum. mined in Michigan 

through 1975 is 66,162,294 tons (59,546,065 t). The 

largest recorded annual tonnage was produced in 

1973 when 1,882,257 tons (1,694,032 t) were mined. 

Most of the gypsum is exported out of the State for 

processing. Michigan has ranked in first place in 

the United States in the production of gypsum in all 

but 7 years since 1945, and in at least second place 

since 1926. 

Petroleum and natural gas.-Mississippian rocks 

have produced significant amounts of petroleum and 

natural gas. The State's first commercial oil field was 

discovered in Berea Sandstone reservoir rocks at 

Saginaw, Mich. in 1925. In 1925 and 1926, 100 percent of the State's oil production, 98,000 barrels, 

came from this field. In 1927, production from the 
MICHIGAN J15 

Berea Sandstone was 434,000 barrels. In the same 

year, however; o.il was discovered in Devonian formations, and exploration for Mississippian Berea 

Sandstone accumulations became less important. 

Since 1927, other Berea reservoirs have been found. 

Annual oil production from thes·e rocks continues 

to decrease and amounted to only 22,921 barrels in 

1976. Total cumulative Mississippian oil production 

through 1976 amounted to 2,546,556 barrels. 

Until recent years, the Michigan Stray-NapoleonMarshall sandstones were the principal Mississippian gas-producing reservoir rocks. The first recorded gas production was in 1931 when 46,232 Mcf 

(thousand cubic feet) was reported. By 1947, annual production was recorded as 19,817,437 Mcf. 

Since that year, production has declined each year 

and amounted to only 169,433 Mcf in 1976. Total 

cumulative Mississippian gas production through 

1976 amounts to 213,538,591 Mcf. Though most of 

the larger Mississippian gas traps appe·ar to have 

been found, smaller accumulations, are occasionally 

found. 

Most of the larger Mississippian, Michigan StrayNapoleon-Marshall gas pools have been converted to 

underground gas-storage reservoirs. Owned and 

operated by gas utility companies, Michigan utilities 

have pioneered the conversion of suitable oil and 

gas traps to natural gas storage. Fifteen Mississippian gas pools, yielding from more than a billion to 

as much as nearly 52 billion cubic feet of native 

gas before conversion, are now in active use. 

F'reshwater reservoirs.-Where Mississippian and 

Pennsylvanian rocks have been flushed of naturally 

occurring brines, the sandstone'S serve as freshwater 

reservoirs or aquifers. Covered by varying thicknesses of glacial drift, these areas are found mainly 

around the subcrop margins in the southern part 

of the basin. Down-dip toward the center of the 

basin they become progressively saline. 

Natural brines.-Natural brines from Mississippian rocks, primarily the Marshall Sandstone, were 

once extensively used for the manufacture of salt 

(NaCl) and other chemical products. Whereas most 

brines used in Michigan's extensive chemical industry are now produced from Devonian or Silurian 

rocks, virtually all Marshall Sandstone brine wells 

have been abandoned and plugged. 

Coal.-Bituminous coal, though not now produced, 

was mined from various coal beds in the Saginaw 

Formation for more than 100 years. As many as 38 

coal mines were in operation at one time during the 

years 1905, 1906, and 1908. Volume of coal production fluctuated; the largest annual tonnage was produced from 37 mines which were in operation in 

1907. The tonnage that year was 2,035,855 tons 

(1,832,270 t). Coal production figures exist for 1860 

through 1953 and for the year 1975. From 1947 

through 1952 only one mine was in operation and 

this was closed in 1952. Total Michigan coal production has amounted to 46,316,580 short tons 

( 41,684,922 t). Production data for the year 1975 

relate to the reopening of a small open-pit mine 

where a small amount of cannel coal was removed 

and sold locally for fireplac.e fuel. Currently no coal 

is actively mined in the State. · 

There has been some renewed interest in Michigan's coal reserves. A recent U.S. Bureau of Mines 

open-file report (Kalliokoski and Welch, 1976, p. 

30) places Michigan coal reserves at approximately 

126.5 million short tons (113.9 million t). The bulk 

of Michigan's coal is only accessible through underground mining. Coal seams are thin, generally less 

than 1 m (3 ft), and frequently discontinuous. 

Water problems and possible hazards associated with 

oil- and gas-test borings throughout many parts of 

the coal-bearing region impose additional limitations to underground mining. Near-surface coal 

seams usually require the removal of large volumes 

of glacial drift and rock overburden. Present-day 

economics and environmental C·onsiderations do not 

favor the revival of Michigan's coal industry. 

OUTCROP LOCALITIES 

A blanket of Pleistocene glacial drift covers all 

the bedrock surface of Michigan. Mississippian and 

Pennsylvanian rocks are exposed at the surface in 

a few locales, but the outcrops are small in vertical 

and lateral extent. Exposures of Mississippian rocks 

are found in 12 of the 68 Southern Peninsula Counties, namely: Arenac, Branch, Calho1:1n, Eaton, Hillsdale, Huron, Iosco, Jackson, Kent, Ogemaw, Sanilac, 

and Tuscola. Pennsylvanian outcrops are found in 

Arenac, Calhoun, Clinton, Huron, Ingham, Ionia, 

Jackson, Saginaw, and Shiawassee Counties. A list 

of reported exposures and type localities of Michigan's Mississippian and Pennsylvanian rocks in the 

aforementioned counties has been docum·ented by 

Martin and Straight (1956, pp. 198-243). The location of these counties is shown in figure 2. 

Quarries or mines afford the best opportunity to 

view partial sections of Michigan's Mississippian 

and Pennsylvanian rocks and to collect fossils. A 
J16 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

selected list of quarries and possible fossil-collecting 

localities follows 3 : 

Coldwater Shale (Mississippian) : 

1. Old abandoned Wolverine Portland Cement Co. shale 

pit. Located approximately 2 miles south and 2 

miles west of Coldwater, Mich., in the C NW% 

sec. 32, T. 6 S., R. 6 W., Branch County. 

2. Old abandoned Peerless Portland Cement Co. shale 

pit. Located approximately 2 miles south and 0. 7 

miles east of Union City, Mich., in the SE%, NE% 

NE 14 sec. 16, T. 5 S., R. 7 W., Branch County. 

3. Old abandoned grindstone quarries in and about the 

community of Grindstone City, Mich., in sec. 25, 

T. 19 N., R. 13 E., Huron County. 

Marshall Sandstone (Mississippian) : 

1. Long abandoned Hanover quarry, approximately 1 

mile south and 1.6 miles west of Hanove·r, Mich. 

Located in the NE14 NW% sec. 31, T. 4 S., R. 2 

W., Jackson County. 

2. Active quarry located approximately 0.5 miles east 

of Napoleon, Mic·h. in the NW% NE% sec. 6, T. 

4 S., R. 2 E., Jackson County. 

Michigan Formation (Mississippian): 

1. Gypsum quarries of the Michigan Gypsum Co. 

Located approximately 4 miles south and 2 miles 

east of Whittemore, Mich. in the C SW% sec. 25, 

T. 21 N., R. 5 E.; C N% NW14 and C S% sec. 31, 

T. 21 N., R. 6 E., Iosco County. 

2. Gypsum quarry of National Gypsum Co. Located approximately 2 ~iles east and 1.1 mile north of 

National City, Mich., in sec. 35, T. 22 N., R. 6 E., 

Iosco County. 

3. Gypsum quarry of the United States Gypsum Co. 

Located just west of Alabaster, Mich. in sec. 27, 

T. 21 N., R. 7 E., Iosco County. 

Bayport Limestone (Mississippian): 

1. Limestone quarry of Wallace Stone Co. Located approximately 2.5 miles east and 1 mile south of 

Bayport, Mich. in sees. 5 and 6, T. 16 N., R. 10 E., 

Huron County. 

2. Limestone quarry of Arenac County Road Commission. Located approximately 2.5 miles and 2 miles 

east of AuGres, Mich. Located in the NW14, Sec. 

5, T. 19 N., R. 7 E., Arenac County. 

3. Limestone quarry of Cheney Limestone Co. Located 

approximately 1 mile west and 0.1 mile north of 

Bellevue, Mich., in theSE% NE% sec. 29, T. 1 N., 

R. 6 W., Eaton County. 

Saginaw Formation (Pennsylvanian): 

1. Shale pits of the Grand Ledge Clay Products Co. 

One pit is located about 1.5 miles northwest of 

Grand Ledge, Mich. in the SW1,4 NE% sec. 3, 

T. 4 N., R. 4 W., Eaton County. Another pit is 

located about 2.5 miles northwest of Grand Ledge 

in the NE% SW14 sec. 34, T. 5 N., R. 4 W., 

Clinton County. 

2. Shale pits of Michigan Brick Inc·. Located about 1.5 

miles northeast of Corunna, Mich. in the E% of 

sec. 22, T. 7 N., R. 3 E., Shiawassee County. 

3 Selection of quarry sites prepared by H. 0. Sorensen, Economic Geologist, Geological Survey Division, Michigan Department of Natural Resources. 

Grand River Formation (Pennsylvanian): 

1. Exposures of Eaton Sandstone are found along the 

north bank of the Grand River in the northwest 

part of the town of Grand Ledge. Also in the 

immediate vicinity are abandoned pits and quarries showing exposures of Eaton Sandstone, several thin coal seams, Verne Limestone, underclays, 

and shales assigned to the Saginaw Formation or 

Saginaw Group of Kelly (1936). 

2. Exposures of Ionia Sandstone, also a part of the 

Grand River Formation are found in old abandoned quarries, approximately 3.5 miles east of 

Ionia, Mich., near the south banks of the Grand 

River in the SW14 NW14 sec. 23, T. 7 N., R. 6 

W., Ionia County. 

REFERENCES CITED 

Andrews, D. A., and Huddle, J. W., 1948, Analyses of Michigan, North Dakota, South Dakota, and Texas coals: U.S. 

Bur. Mines Tech. Paper 700, p. 1-4, 32-41. 

Ball, M. W., Weaver, T. F., Crider, H. D., and Ball, D. S., 

1941, Shoestring gas fields of Michigan, in Levorsen, 

A. I., ed., Stratigraphic type oil fields: Tulsa, Okla., Am. 

Assoc. Petroleum Geologists, p. 237-266. 

Baltrusaitis, E. J., 1974, Middle Devonian bentonite in Michigan basin: Am. Assoc. Petroleum Geologists Bull., v. 58, 

no. 7, p. 1323-1330. 

Case, E. C., and Robinson, W. I., 1915, The geology of Limestone Mountain and Sherman Hill in Houghton County, 

Michigan: Michigan Geol. Survey Pub. 18, Geol. ser. 

15, p. 165-181. 

Cohee, G. V., and Underwood, L. B., 1944, Maps and sections 

of the Berea sandstone in Eastern Michigan: U.S. Geol. 

Survey Oil and Gas Inv. Map OM-17. 

Cohee, G. V., Burns, R. N., Brown, Andrew, Brant, R. A., and 

Wright, Dorothy, 1950, Coal Resources of Michigan: 

U.S. Geol. Survey Circ. 77, 56 p. 

Cohee, G. V., Macha, Carol, and Holk, Margery, 1951, Thickness and lithology of Upper Devonian and Carboniferous 

rocks in Michigan: U.S. Geol. Survey Oil and Gas Inv. 

Chart OC-41, 5 sheets, 19 p. 

Cohee, G. V., 1965, Geologic history of the Michigan basin: 

Washington Acad. Sci. Jour., v. 55, no. 9, p. 211-223. 

Cooper, W. F., 1906, Geological report on Bay County: Michigan Geol. Survey, Ann. Rept. 1905, p. 135-426. 

---1909, Report on the geology of Tuscola County, Mich.; 

Paleozoic geology: Michgan Geol. Survey, Rept. 1908, 

p. 175-196. 

Cross, A. T., 1966, Palynologic evidence of Mid-Mesozoic age 

of Fort Dodge (Iowa) gypsum [abs.]: Geol. Soc. America, Ann. Mtg., San Francisco, Calif., 1966, Program, p. 

46. 

DeWitt, Jr., Wallace, 1970, Age of the Bedford Shale, Herea 

Sandstone, and Sunbury Shale in the Appalachian and 

Michigan basins, Pennsylvania, Ohio, and Michigan: 

U.S. Geol. Survey Bull. 1294-G, p. G1-Gll. 

Douglass, C. C., 1841, Michigan Legal Document, v. 1, no. 2, 

4th Ann. Rept. of State Geologist for 1840, p. 545-551. 

Ells, G. D., 1969, Architecture of the Michigan basin, in 

Michigan Basin Geological Society Ann. Field Excursion, East Lansing, Mich., 1969, Studies of the Precambrian of the Michigan basin: p. 60-88. 
MICHIGAN J17 

Ells, G. D., Kelley, R. W., Hardenberg, H. J., Johnson, L. D., 

and Sorensen, H. 0., 1964, Stratigraphic succession in 

Michigan, Paleozoic through Recent, Chart 1: Michigan 

Geol. Survey Div. 

Hale, Lucille, 1941, Study of sedimentation and stratigraphy 

of lower Mississippian in western Michigan: Am. Assoc. 

Petroleum Geologists Bull., v. 25 no. 4, p. 713-723. 

Kalliokoski, J., and Welch, E. J., 1976, Magnitude and quality 

of Michigan's coal reserves: U.S. Bur. Mines open-file 

report, OFR-102-76. 

Kelley, R. W., 1968, Bedrock of Michigan: Michigan Geol. 

Survey, Small Scale Map 2. 

Kelly, W. A., 1930, Lower Pennsylvanian faunas from Michigan: Jour. Paleontology, v. 4, no. 2, p. 129-151. 

---1931, A review of the stratigraphy of the Saginaw 

Formation: Michigan Acad. Sci. Paper, v. 14, p. 453-469. 

---1933, Pennsylvanian stratigraphy near Grand Ledge, 

Michigan: Jour. Geology, v. 41, pt. 1, p. 77-89. 

---1936, The Pennsylvanian system of Michigan: Michigan Geol. Survey Pub. 40, Geol. ser. 34, pt. 2, p. 149-226. 

Lane, A. C., 1895, The geology of Lower Michigan with 

reference to deep borings: Michigan Geol. Survey, v. 5, 

pt. 2, 100 p. 

---1901, [Suggested changes in nomenclature of Michigan 

formations]: Michigan Miner, v. 3, no. 10, p. 9. 

---1909, Notes on the geological section of Michigan; 

Part II, From the St. Peters up: Michigan Geol. Survey, 

Report 1908, pt. 2, p. 43-105. 

Lineback, J. A., 1970, Stratigraphy of the New Albany Shale 

in Indiana: Indiana Geol. Survey Bull. 44, 73 p. 

Martin, H. M., and Straight, M. T., 1956, An index of the 

geology of Michigan, 1823-1955: Michigan Geol. Survey 

Pub. 50, 461 p. 

Newcombe, R. B., 1931, Map of areal geology of Michigan, 

southe·rn peninsula: [Lansing, Michigan Geol. Survey 

Division]. 

---1933, Oil and gas fields of Michigan: Michigan Geol. 

Survey Pub. 38, Geol. ser. 32, 293 p. 

Rominger, C. L., 1876, Geology of the Lower Peninsula: 

Michigan Geol. Survey, v. 3, pt. 1, 225 p. 

Smith, R. A., 1912, Michigan coal, Mineral resources of 

Michigan: Michigan Geol. Survey Pub. 8, ser. 6, p. 

257-303. 

Stanley, G. M., 1945, Geology of the Mackinac Straits region: 

Michigan Geol. Survey Pub. 44, Geol. ser. 37, 204 p. 

Wanless, H. R., and Shideler, G. L., 1975, Introduction and 

regional analyses of the Pennsylvanian System, pt. 1 of 

McKee, E. D., and others, Paleotectonic investigations 

of the Pennsylvanian System in the United States: U.S. 

Geol. Survey Prof. Paper 853, p. 63-70. 

Williman, H. B., 1962, The Silurian strata of northeastern 

Illinois in Michigan Basin , Geol. Soc.; Silurian rocks of 

the southern Lake Michigan area-Ann. Field Conference, 1962: Lansing, Michigan, p. 61-68. 

Winchell, Alexander, 1861, First biennial report of the progress of the geolocial survey of Michigan-lower peninsula: Lansing, Michigan Geol. Survey, 339 p. 
The Mississippian and Pennsylvanian 

(Carboniferous) Systems in the United StatesIndiana 

By HENRY H. GRAY 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1110-K 

Prepared in cooperation with the 

Indiana Geological Survey, 

Department of Natural Resources 

Historical review and summary of areal, 

stratigraphic, structural, and economic 

geology of Mississippian and 

Pennsylvanian rocks in Indiana 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1979 

FIGURE 1. 

2. 

3. 

4. 

5. 

CONTENTS 

Page 

Abstract ----------------------------------------------------------------- ]{1 

Introduction ------------------------------------------------------------- 1 

Some basic facts ----------------------------------------------------- 1 

History of geologic work and evolution of nomenclature ------------------ 3 

Geologic setting _________________________________________________ ---- _ 5 

Acknowledgments ---------------------------------------------------- 6 

The Devonian-Mississippian boundary and earliest Mississippian rocks -------- 7 

The Mississippian System _ __ _ _ _ _ __ _ _ _ _ _ _ __ _ _ __ __ __ _ _ __ _ __ _ _ _ _ _ _ _ ____ __ _ ___ 7 

Borden Group -------------------------------------------------------- 7 

Sanders and Blue River Groups ---------------------------------------- 9 

West Baden and Stephensport Groups and unnamed Upper Chesterian group 10 

Age and correlation of Mississippian rocks ------------------------------ 11 

The Mississippian-Pennsylvanian unconformity ------------------------------ 11 

The Pennsylvanian System ------------------------------------------------ 12 Raccoon Creek Group _ _ _ _ _ _ _ _ _ _ _ _ _ _ ____ _ _ _ __ _ _ _ _ _ _ ___ _ _ _ _ _ __ _ ____ _ _ _ __ 13 

Carbondale Group ---------------------------------------------------- 14 

McLeansboro Group -------------------------------------------------- 15 

Age and correlation of 'Pennsylvanian rocks ----------------------------- 16 

References cited ---------------------------------------------------------- 17 

ILLUSTRATIONS 

Map of Indiana showing distribution of Mississippian and Pennsylvanian rocks -----------------------

Evolution of Mississippian rock-unit nomenclature in southwestern Indiana ---------------------------

Evolution of Pennsylvanian rock-unit nomenclature in Indiana --------------------------------------

Columnar section showing exposed Mississippian rocks in Indiana -----------------------------------

Columnar section showing exposed Pennsylvanian rocks in Indiana -----------------------------------

lll 

Page 

]{2 

4 

5 

8 

13 
THE MISSISSIPPIAN AND PENNSYLVANIAN (CARBONIFEROUS) 

SYSTEMS IN THE UNITED STATES-INDIANA1 

By HENRY H. GRAY2 

ABSTRACT 

Rocks of the Mississippian System are widespread in 

southwestern Indiana, where they reach a maximum exposed 

thickness of about 600 m .. All parts of the period are represented, but the lowest series, the Kinderhookian, is very 

thin. Early Valmeyeran rocks consist of shale and siltstone; 

later Valmeyeran rocks are a sequence of limestone formations. Rocks of the Chesterian Series contain repeated 

alternations of limestone, sandstone, and shale. 

The lower boundary of the Mississippian System is in a 

black shale sequence, is faunally determined, and has no 

phy.sical expression. The upper boundary is a disconformity 

which has relief as great as 100 m. Mississippian rocks we·re 

uplifted, tilted, and erosionally beveled before deposition of 

Pennsylvanian sediments, so that Pennsylvanian rocks rest 

on youngest Mississippian rocks at the southern border of 

Indiana and on progressively older rocks northward. 

Rocks of the Pennsylvanian System are widespread in 

southwestern Indiana, where they reach a maximum thickness of 500 m. Repeated cyclic sequences of sandstone, shale, 

coal, and limestone characterize the entire system, but subtle 

vertical distinctions may be perceived. In rocks of the Morrowan and Atokan Series, sandstone is the prominent rock 

type, and beds of coal are thin and local. The Desmoinesian 

Series, in which 1shale is dominant, contains five major commercial beds of coal. The Missourian Series also consists 

mainly of shale, but beds of coal are scattered and thin. Rocks 

of latest Pennsylvanian (Virgilian) age are not represented 

in Indiana. 

INTRODUCTION 

SOME BASIC FACTS 

From the time of the first systematic geologic inves·tigations in Indiana (Owen, 1838, 1839), it has 

been clear that rocks which in many other parts of 

the world are assigned to a single geologic system, 

the Carboniferous, here are divided into two lithologically distinct parts by a locally and regionally 

conspicuous unconformity. Classic study areas from 

1 Published by pet·mission of the State Geologist, Indiana Geological 

Survey, Department o.f Natural Resources, Bloomington, Ind. 47401. 

D Head Stratigrapher, Indiana Geological Survey, Department of Natural 

Resources, Bloomington, Ind. 47401. 

which evolved the concept of the Mississippian System for the lower o.f these divisions are not far to 

the west; classic study areas from which evolved the 

concept of the Pennsylvanian System for the upper · 

of these divisions are not far to the east. These two 

systemic terms have had increasingly common usage 

in Indiana for nearly 100 years, and they will be 

used in this report. 

Rocks of the Pennsylvanian Sy~stem underlie an 

area of nearly 19,000 km2 in southwestern Indiana, 

or about one-fifth of the State's total area (fig. 1). 

The rocks constitute a dominantly clastic sequence 

of shale, siltstone·, and sandstone, and intercalated 

thin but widespread beds of clay, coal, black shale, 

and limestone. Their maximum thickness is about 

500 m near the southwest corner of the State; their 

mean thickness, however, is about half that figure, 

so that these rocks have a total volume of about 

5,000 km3 • From these rocks is produced a large 

share of the State's mineral wealth. The total value 

of raw-mineral comm:odities produced from Pennsylvanian rocks in Indiana in 1976 was about $300 

million (Indiana Geological Survey, 1977). Nearly 

all thi:s value was derived from coal, which was 

mined mostly by stripping; of less·er value were oil, 

clay and shale, sandstone, and limestone. 

Most of the area underlain by Pennsylvanian 

rocks is covered by residual soil or by younger unconsolidated deposits, which include till of Wisconsinan and Illinoian (late Plei:stocene) ages and associated outwash sand and gravel, glacial lake silt 

and clay, loess, dune sand, and Holocene alluvium. 

Thickness of this cover is as much as 45 min buried 

valleys near the confluence of the Wabash and Ohio 

Rivers, but ov·er large areas the cover is less than a 

meter to a few meters thick. Scattered exposures of 

the bedrock are distributed throughout the area, but 

most of the larger exposures are found in the upland along the eastern margin of the outcrop belt 

and in strip mines that follow the crop line of the 

Kl 
K2 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

EXPLANATION 

McLeansboro Group 

Shale, sandstone, limestone, 

and thin coal 

wt~~mml Carbondale Group 

Shale, sand~one, limestone, 

clay, and coal 

l\\\\\\\\\;~1\\l\\ll[\\~ ·Raccoon Creek Group 

Shale, sandstone, limestone, 

clay, and coal 

,,:.,,,~,I·JI!oo:~J::,,_ .. :IIII:II 

West Baden and Stephensport Groups 

and unnamed upper Chesterian Group 

Shale, sandstone, and limestone 

Sanders and 

~ Blue River Groups 

Limestone 

Rockford Limestone and Borden Group 

(south); Coldwater Shale (north) 

Siltstone, shale, ~nd thin limestone 

New Albany Shale (south); 

Antrim and Ellsworth Shales (north) 

Black and greenish-gray shale 

0 

Ordovician, Silurian, and Middle 

Devonian rocks 

Wisconsinan glacial boundary 

Boundary of older glaciations 

I 

/ 

0 50 

0 50 100 KILOMETERS 

00 

I 

I /./ 

} 

I 

I 

I 

100 MILES 

FIGURE 1.-Map of Indiana showing distribution of Mississippian and Pennsylvanian rocks. 
INDIANA K3 

major beds of coal in a north-northwest trend across 

the midsection of the belt. 

The contact between rocks of the Pennsylvanian 

System and underlying rocks is a well-defined unconformity whose surface, as reconstructed from 

outcrop and subsurface data, has the aspect of a 

southwest-sloping plateau entrenched as much as 

50 to 100 m by integrated systems of southwesttrending consequent stream valleys. Because of local 

relief on the unconformity, Pennsylvanian rocks in 

any given area may rest on several older formations, 

but a regional trend also exists because the older 

rocks were slightly tilted and erosionally beveled 

before deposition of basal Pennsylvanian sediments. 

As a result, Pennsylvanian rocks rest on youngest 

Mississippian rocks at the southern extremity of the 

outcrop area and on progressively older rocks 

northward. Along the main outcrop belt, the unconformity truncates almost the entire Mississippian System; in scattered outliers to the northeast, 

Pennsylvanian rocks lie on black shale of late Devonian age. 

Rocks of the Mississippian System are at the bedrock surface in southwestern Indiana in an area 

of about 18,000 km:! (fig. 1). They underlie Pennsylvanian rocks in the area previously described, 

and in northern Indiana they are at the bedrock 

surface in an additional area of nearly 4,000 km:!. 

Thus, in all they underlie slightly more than 40,000 

km:!, or a little more than two-fifths of the State. 

These rocks are divisible into three lithologically distinct parts. The upper part, which compris·es repeated cyclic sequences of sandstone, shale, and 

limestone, and the middle part, which consists principally of limestone of many textural varieties, are 

restricted to southwestern Indiana. The lower part, 

a clastic sequence of siltstone and shale, is present 

in both northern and southwestern Indiana. 

In the southwestern outcrop area, Mississippian 

rocks are thickest near the Ohio River, where they 

attain a thickness of 600 m. They thin progressively 

northward, mainly as a result of the truncation 

earlier described, so that in west-central Indiana 

they are only about 100 m thick. In northernmost 

Indiana, their maximum thickness is about 200 m. 

The total volume of Mississippian rocks in Indiana 

is about 11,000 km\ and the total value of rawmineral commodities produced from these rocks in 

1976 was about $60 million (Indiana Geological Survey, 1977). Mississippian rocks are the major 

source of oil in Indiana (Carpenter and others, 

1975, p. 43). Also of importance are limestone (used 

principally for crushed stone, cement, and dimension stone), gypsum, shale, and sandstone. 

In their northern area of occurrence (fig. 1), Mississippian rocks are entirely covered by glacial deposits; not a single exposure is known. Much of the 

southwestern area also is covered, although more 

thinly, by the same kinds of unconsolidated deposits 

that cover adjacent areas of Pennsylvanian rocks. 

In much of south-central Indiana, however, Mississippian rocks underlie only thin residual deposits 

and loess. Exposures thus are rather com.mon, especially in large quarries in the lim.estone belt that 

trends northwestward .from the Ohio River to 

c~entral western Indiana. 

Rocks in southwestern Indiana dip west-southwest at the rate of about 5 m/km away from the 

crest o.f the Cincinnati arch near the eastern border 

of the State and toward the axis of the Illinois 

basin. A few normal faults that ha~e displacements 

as great as 60 m are known, mostly along the 

Wabash River near the southwest corner of the 

State. Rocks in northern Indiana dip northward at 

a similar rate toward the center of the Michigan 

basin. 

HISTORY OF GEOLOGIC WORK AND EVOLUTION 

OF NOMENCLATURE 

The history of geologic study of these rocks is 

long, and only a few of the works on which the 

present overview is based may be mentioned. Some 

of the important schemes of stratigraphic classification that have be·en used in this area are outlined in 

figures 2 and 3. Evolution of the nomenclature was 

discussed in detail by Cumings (1922), and more 

recently a brief review and an updating were presented in Shav'er and others (1970). 

Serious original research into Indiana geology began in 1837, when pioneer geologist David Dale 

Owen was appointed State Geologist and was instructed to make a 1-year survey that later was extended for an additional year (Owen, 1838, 1839). 

Owen's reports were printed many times; the most 

widely available version, which was considerably 

revis,ed from earlier printings, is the 1859 printing 

(Owen, 1859a, b). Cumings (1922, p. 475) credited 

Owen as being the first geologist in American to 

recognize the twofold nature of the Carboniferous 

System, although, in a sense, Owen's classification 

was m·erely derived from the Mountain LimestoneCoal Measures scheme that had come into use in 

Europe, where 9wen had been schooled. By 1859, 

Owen had refined and restated the definition of his 

"sub-carboniferous group" so that it almost exactly 
K4 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

Current usage Series 

Owen, 1859 a,b .Hopkins, 1904 Cumings, 1922; modified from Shaver and others, 1970 

Logan, 1932 

Group Formation 

Negli Creek Limestone 

--

Siberia I r:: 

.!!! 

-- I -- -- :; 

I E 

Limestone co 

z ---

Tar Springs Sandstone Tar Springs Formation 

Archimedes Glen Dean Limestone Glen Dean Limestone r:: 

.!!! 

and Huron Limestone, Hardinsburg Sandstone Hardinsburg Formation Q) 

Pentremital Sandstone, and Shale Golconda Limestone Haney Limestone ti 

Limestones Q) 

Stephensport .t:: 

c. Indian Springs Shale u ::I Big Clifty Formation 

e Cypress Sandstone (!) Beech Creek Limestone Beech Creek Limestone Ill 

::I 

e Elwren Formation Elwren Formation 

.e! Reelsville Limestone Reelsville Limestone ·c r:: 

0 Sample Sandstone West Baden Sample Formation co 

-€ 

Q) 

Ill 

co Beaver Bend Limestone Beaver Bend Limestone > ~ 

.c Mooretown Sandstone Bethel Formation ::I 

(/) Paoli Limestone Paoli Limestone 

Mitchell Ste. Genevieve Limestone Blue River Limestone Ste. Genevieve Limestone 

Barren St. Louis Limestone St. Louis Limestone 

Limestone Bedford Oolitic Limestone Salem Limestone Salem Limestone r:: 

Harrodsburg Sanders 

Harrodsburg Limestone Harrodsburg Limestone E 

Limestone Q) 

Ramp Creek Formation > 

Q) 

Knobstone 

Edwardsville Formation. Edwardsville 

I 

E r:: 

-- iii co 

or Knobstone Floyds Knob Formation Formation > 'iii 

Sub-carboniferous Shale Borden '(ij 

--- --- r:: 

Sandstone 5 

New Providence Formation New Providence Shale 0 

I-

--- Rockford Goniatite Limestone Rockford Limestone 

--

Rockford Limestone ~ 

Black Bituminous 

Aluminous Slate New Albany Shale New Albany Shale New Albany Shale Chaut. Fam. 

FIGURE 2.-Evolution of Mississippian rock-unit nomenclature in southwestern Indiana. Minor boundary changes are not 

indicated. Units marked-either received no name or received names that have been shown to be not useful. Kind.= 

Kinderhookian, earliest Mississippian. Chaut.=Chautauquan, Fam.=Famennian, latest Devonian. 

included what now constitutes the Mississippian 

System (fig. 2). He further recognized and described (Owen, 1859a, p. 20-23) a threefold lithologic division of the "sub-carboniferous group." 

D. D. Owen embarked on another survey in 1859, 

but he died before the work was finished, and it 

was completed by his brother Richard (Owen, 1862). 

This report includes a section by Leo Lesquereux 

( 1862) specifically describing the Coal Measures of 

Indiana. A few years later, a State geological survey was established as a continuing organization 

that has functioned, though the name has changed 

several times, until the present. Much of the research on the stratigraphy of Mississippian and 

Pennsylvanian rocks in Indiana has been done under the aegis of this organization. 

In the early years, the Indiana Geological Survey 

concentrated on preparation of areal reports. In 

1895, however, a new State Geologist, W. S. Blatchley, brought with him a "plan for taking up each of 

the great natural resources of the State" (Blatchley, 1897, p. 6). Backed by a corps of able assistants, 

many of whom later became nationally known, he 

produced a series of reports that remained definitive 

for many years. Worthy of mention in the present 

context are studies of the Carboniferous sandstones 

(Hopkins, 1896; Kindle, 1896), the famous dimension limestone (Hopkins and Siehenthal, 1897; 

Cumings and others, 1906), coal (Ashley, 1899, 

1909), the lower Carboniferous (Ashley and Kindle, 

1903), and the first detailed geologic map of the 

State, toward which many of the earlier studies 

were directed (Hopkins, 1904). Also during this 

period, two folio reports on the coal-bearing area 

were prepared by the U.S. Geological Survey to add 

to the then rapidly expanding Geologic Atlas o.f the 
INDIANA K5 

Owen, 1859 a,b; Ashley, 1899, 1909 

Cumings, 1922; 

Shaver and others, 1970 Series 

Lesquereux, 1862 Division Coal Logan, 1932 

Group Formation Member 

:~:~h If Mattoon Merom Sandstone c: c: c: .!!! co co :; ·c: 

Livingston Limestone :.c: co 

e 0 .r. 

IX Bond Cl Cl) c. 0 ::::1 Cl) 

.g co ~ Q) 

c: Shoal Creek Limestone E ci5 co Q) 

Q) c: ..J Patoka 0 (,) 

~ u 

VIII Shelburn West Franklin Limestone 

Shelburn 

VII VII Danville Coal 

VI VI Dugger 

Petersburg Hymera Coal 

Coal Measures v Q) c: 'iii c: v '0 Springfield Coal co co c: Petersburg ·c: 'iii 0 Q) Q) c: .Q c: IV 5 .r. .!!! Cl '(5 iii 

IV Survant Coal ~ E .r. <i: Cl) c. Q) 

lila Staunton Linton 0 1ii 

Colchester Coal Q) 

Ill ~ 

Ill Seelyville Coal 

II II Staunton 

Perth Limestone 

Brazil ~ 

Q) Minshall Coal c: ~ co 

u Brazil ~ 

c: ~ 

~ 

c: Lower Block Coal 

0 

0 ~ 

I (,) ·:;: (,) Lead Creek Limestone Cl) co 

0:: ~ 

0 c: c: 

Mansfield 

Q.. co co Mansfield Pinnick Coal ~ ·;:: 

::::1 

0 E r 

t French Lick Coal co ~ z 

FIGURE 3.-Evolution of Pennsylvanian rock-unit nomenclature in Indiana. 

United States (Fuller and Ashley, 1902; Fuller arid 

Clapp, 1904). 

The impetus of the Blatchley organization was 

not maintained, however, and the focus of geologic 

research shifted to Indiana University. Perhaps because the Ashley reports on coal were so thorough, 

faculty and students turned their attention mainly 

to the Mississippian rocks. Notable among these 

studies were those of Malott (1915, 1919, 1925, 

1952) and Stockdale (1931, 1939). The present era 

of activity in the study of Indiana geology began 

when C. F. Deiss be,came Stat~e Geologist in 1946. 

In addition to renewed emphasis on mapping (Perry 

and Smith, 1958; Melhorn and Smith, 1959; Gray 

and others, 1960; Hutchison, 1960, 1976; Sunderman, 1968), interest has been extended into the 

vast store of subsurface data (Pinsak, 1957; Sullivan, 1972), and a series of Coal Investigations Maps 

has been prepared in cooperation with the U.S. 

Geological Survey (Friedman, 1961; Hutchison, 

1958; Kottlowski, 1954, 1959, 1960; Waddell, 1954; 

Wier, 1950, 1951, 1954a). 

The current definitive statewide geologic maps of 

Indiana consist of a series of Regional Geologic Maps 

published by the Indiana Geological Survey with 

the cooperation of geologists in adjacent States. 

Each of these maps covers an area of 1 o in latitude 

by 2° in longitude and shows both bedrock and unconsolidated deposits on a scale of 1: 250,000 Principal areas of outcropping Mississippian and Pennsylvanian rocks are shown on the Danville (Wayne, 

Johnson, and Keller, 1966), Indianapolis (Wier and 

Gray, (1961), Vincennes (Gray, Wayne, and Wier, 

1970), and Louisville (Gray, 1972) quadrangles. 

GEOLOGIC SETTING 

Indiana lies astride the northwestward extension 

of the Cincinnati arch, a broad, gentle structural rise 
K6 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

that divides the basins adjoining on the north, east, 

and west. Mississippian rocks in the Michigan basin 

are no closer to their Illinois basin counterparts 

than 150 km; Pennsylvanian rocks are separated by 

twice that distance. The early Paleozoic history of 

this structural feature is elusive, but by mid-Paleozoic time an arch in this general geographic position 

clearly was influencing sedimentation. In the late 

Paleozoic, this feature dominated the pal,eogeographic and paleotectonic patterns. During Mississippian and Pennsylvanian time, an arch separated 

the Michigan and Illinois basins so effectively that 

their depositional histories are quite distinct. Since 

the Pennsylvanian, these areas have been relatively 

stable tectonically so that the present structure 

fairly adequately portrays the tectonic framework 

that influenced late Paleozoic sedimentation. 

In southwestern Indiana, the Devonian-Mississippian transition is plac·ed near the top of a black 

shale, the New Albany Shale (fig. 2; Lineback, 1970, 

fig. 16). In northern Indiana, the transition is near 

the top of the Ellsworth Shale, which itself is transitional from the underlying black Antrim Shale to 

the overlying greenish-gray Coldwater Shale. Thus, 

the close of the Devonian Period is not marked by 

any obvious tectonic event in this area-yet there 

was a change in the character of the sediment, from 

black mud indicative of stagnant bottom conditions 

to greenish-gray mud that represents more oxygenated bottom conditions; this change m1arks the 

beginning of a prograding deltaic sequence that in 

turn reflect uplift of a source area far to the north 

and east. During earliest Mississippian time, however, the sedimentation rate remained exceedingly 

slow, so that the entire Kinderhookian Epoch is 

represented by scarcely more than a meter of shale 

and limestone (fig. 4). 

Early in Valmeyeran time, a great delta composed 

mainly of silt was built along the eastern margin 

of the Illinois basin, but the prograding deltaic 

wedge failed to fill the basin. Carbonate-rock units 

not represented at the surface in Indiana succeeded 

the deltaic silt in deeper parts of the basin (Lineback, 1969), and it was not until middle Valmeyeran 

time that the deep basin was filled to overflowing. 

For the later half of Valmeyeran tim-e, normal 

shelf-type shallow-water carbonate sedimentation 

was dominant. 

A strong terrigenous influence again prevailed as 

the Chesterian E-poch began. Clastic materials 

poured into the Illinois basin from the northeast 

(Potter and others, 1958, Swann, 1964). These sediments ,appear to have bypassed the Michigan basin, 

which may have been full to the brim at the time. 

Vaccilating shorelines, deltas, and shallow seas are 

recorded by the deposits, in which terrigenous clastic and indigenous carbonate deposits alternate to 

form a pattern that has been called rhythmic 

(Swann, 1964). Clearly, at this time an approximate 

balance had been achieved between the rates of sedimentation and of subsidence. At the very end of 

Mississippian time or during earliest Pennsylvanian, the recently deposited sediments were slightly 

uplifted and tilted gently toward the west. Erosion 

shaped the newly emergent land into a surface of 

gently rolling uplands that here and there were 

rather sharply entrenched by consequent streams. 

As the Illinois basin subsided slightly, deposition 

once more began about middle Morrowan time (fig. 

5). A cyclic sedimentation pattern again is evident, 

but sediments are more continental than before; 

thus, few sediments represent offshore marine conditions and more are typical of deltaic and fluvial 

conditions (Wanless and others, 1970). Notable, 

though volumetrically m.inor, are deposits associated 

with coal-swamp environments. Beds of coal, underclay, and black roof shale are distributed throughout the Pennsylvanian rocks of Indiana, but the 

principal beds of coal are of Desmoinesian age. 

Rocks of the Pennsylvanian System constitute the 

youngest bedrock in Indiana. Permian rocks have 

not been identified in the Illinois basin ; Cretaceous 

rocks are known in southern and western Illinois 

(Willman and others, 1975, p. 205-206) but have 

not been found in Indiana. Some scattered occurrences of chert· gravel are provisionally assigned to 

the Miocene or Pliocene (Lafayette Gravel, Shaver 

and others, 1970, p. 86-87; Luce Gravel, Ray, 1965, 

p. 17-21), but the geologic materials that overlie 

Pennsylvanian rocks in most areas are glacially related deposits of late Pleistocene age. 

The stratigraphic nomenclature used in this paper 

has not been reviewed by the Geologic Names Comm.ittee of the U.S. Geological Survey. The nomenclature used here conforms with the current usage of 

the Indiana Geological Survey. 

ACKNOWLEDGMENTS 

Among the many colleagues. to whom I am grateful for critical review and assistance in preparing 

this report are C. H. Ault, D. D. Carr, A. S. Horowitz, H. C. Hutchinson, R. L. Powell, C. B. Rexroad, R. H. Shaver, and C. E. Wier. 
INDIANA K7 

THE DEVONIAN-MISSISSIPPIAN BOUNDARY 

AND EARLIEST MISSISSIPPIAN ROCKS 

In southern and western Indiana, the DevonianMississippian boundary is recognized within and 

near the top of the New Albany Shale (fig. 4). 

This formation consists predominantly of brownishblack partly dolomitic shale that contains as much 

as 20 percent by weight organic matter. Greenishgray shale and mudstone that contain very little 

organic matter make up a lesser part of the formation. Rather uniformly about 35 m thick in the outcrop belt (fig. 1), the New Albany Shale thickens 

westward in the subsurface (Lineback, 1970). 

Deposition of the Albany Shale began late in 

middle Devonian time and ended in middle Kinderhookian (early Mississippian) time. Conodont assemblages representative of two of the six zones of 

the standard upper Devonian sequence of Germany (Zones to! and toll!) are recognized in the 

lower and middle parts of the New Albany Shale, 

and assemblages indicative of early Mississippian 

age (Zones cui and cull) are known from the 

uppermost 0.5 m of the formation. From this and 

other faunal evidence, the Devonian-Mississippian 

boundary in southern Indiana can be· placed about 

0.6 to 1.8 m below the top of the New Albany Shale, 

but the boundary has no physical expression and 

cannot be m,ore precisely located because definitive 

faunas do not occur at critical stratigraphic positions (Lineback, 1970, p. 39). 

In northernmost Indiana, rocks equivalent to the 

New Albany Shale include the Antrim Shale, a 

brownish-black shale that is much like the New Albany, and the overlying Ellsworth Shale, a greenishgray shale that has a transitional zone of interbedded brownish-black and greenish-gray shale at 

the base. T.ogether, these two formations are about 

60 m thick near the margin of the Michigan basin. 

Because of the thick glacial cover, these rocks are 

nowhere exposed. Sparse subsurface data ·suggest 

that the upper part of the Ellsworth Shale can be 

traced eastward into rocks in Ohio that are assigned to the Bedford Shale and the Berea Sandstone, and therefore is Mississippian in age. 

Earliest Mississippian rocks in southern Indiana 

constitute many thin named beds in the uppermost 

part of the New Albany Shale. These include, in 

ascending order, a 6-cm bed of phosphatic nodules, 

the Falling Run Bed; a 12-cm. bed of greenish-gray 

shale, the Underwood Bed; a 25-cm bed of black 

fissile shale, the Henryville Bed; and a 12-cm bed 

of greenish-gray glauconitic mudstone, the Jacobs 

Chapel Bed (Lineback, 1970, p. 27-29). None of 

these units is geographically extensive, but they are 

of interest because of the shifting environments 

that they suggest and because of the rich and varied 

faunas that they contain. Included are conodonts, 

scolecodonts, bryozoans, crinoids, brachiopods, gastropods, pelecypods, arthropods, fish, plants, and 

associated ichnofossHs. An especially diverse conodont fauna has been found in the Jacobs Chapel Bed 

(Rexroad, 1969). All faunas indicate a Kinderhookian age. 

Overlying the New Albany Shale, and forming a 

distinctive marker bed that separates the New Albany from the Borden Group above, is the Rockford 

Limestone (fig. 4). This formation, which commonly 

is about a meter thick, is a greenish-gray micritic 

dolomite (Lineback, 1970, p. 35). It has a fairly 

abundant and varied conodont fauna from which a 

latest Kinderhookian to earliest Valmeyeran ( Osagean) age has been determined (Rexroad and Scott, 

1964), but possibly the most interesting elements in 

the otherwise spars·e fauna are the several species 

of goniatites and nautiloids that have been known 

since ~the time of Verneuil (1847). Recent collections from sites in two widely separated areas have 

also been described ( Gutschick and Treckman, 

1957; Lineback, 1963). 

The Rockford Limestone is overlain by the New 

Providence Shale (fig. 4). The contact is a disconformity of very low relief, so that in some places the 

Rockford is missing and the New Providence rests 

directly on uppermost parts of the New Albany 

Shale (Lineback, 1970, p. 35-37). 

THE MISSISSIPPIAN SYSTEM 

Earliest Mississippian rocks, which represent 

Kinderhookian and part of Valmeyeran time, are 

very thin and have for convenience been discussed 

in connection with the Devonian-Mississippian 

boundary. The greater thickness of the Mississippian System in Indiana comprises three nearly equal 

parts: a clastic s·equence (Borden Group) that is 

Valmeyeran in age a carbonate rock sequence 

(Sanders and Blue River Groups) that is Valmeyeran and earliest Chesterian in age and a m.ixed 

clastic-carbonate cyclic sequence (West Baden and 

Stephensport Groups and an unnamed group) that 

is Chesterian in age (fig. 4) . 

BORDEN GROUP 

The most comprehensive study of the Borden 

Group is that of Stockdale (1931) who identified 
K8 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

~ 

~ Vl 

>- Vl 

z 

nh 

z 

<( 

a.. 

CJ) 

CJ) 

CJ) 

DEV. 

Vl 

w 

ffi 

Vl 

1---

z 

<( 

0:: 

w 

ICJ) 

w 

:::L 

u 

'----

z 

<( 

a: 

w 

>-

w 

.....J 

<( 

> 

VlVlVJ 

wa: 

zw 

:.<:1-

uw 

~! 

---~ 

=-~~ .. ~. 

~--=-~ Unnamed group 

500-~_§ --=----

300 

- ·······~ 

~ =~----------------~ 

~;.::~·-_____ T:_~r-~_~_;i~-~-s--.L-----1 ------=l 

: ::=.~· .. ::· ., .. '• .... ·. · .. 

·-t Stephensport 

Group 

West Baden 

Group 

Paoli Limestone 

Ste. Genevieve 

Limestone 

St. Louis 

Limestone 

Salem 

Limestone ~ c. 

~~~~ Q)::::l 

------l"ge 

Harrodsburg Limestone ~ <!l 

= 

= = . Ramo Creek Formation 

~--··;- .. z=·· 200 -:=~_:_:_:·.· .. ·.:: 

Edwardsville 

Formation 

0 

~-:-:-:-...:..:..:..-:-:-:-...:..:..:.. .. ~-:-:-:-..:..:..._--::-:..:..:.:... 

~·. 

- -_-_-=---:: 

Borden 

Group 

New. Providence 

Shale 

Rockford Limestone 

New Albany Shale 

FIGURE 4.-Columnar section showing exposed Mississippian Rocks in Indiana. K.=Kinderhookian. 

in the group five formations and a large number of 

lithic units that he designated facies and within 

which he recognized many members. Only a few 

of his names are still in use but his study remains 

a repository of factual da.ta. The Borden Group represents a late and distal tongue of the great Catskill-Mauch Chunk delta system of the northern 

Appalachians but most of the sediment that was 

deposited in the Illinois basin pr·obably had a northeastern source (Swann and others 1965). 

The Borden Group comprises a rather straightforward prodelta-delta sequence. The green-gray 

and red-brown soft New Providence Shale represents the prodelta deposits; the overlying sequence 

of siltst.ones (fig. 4) varies from clay poor and 

sandstonelike to clay rich and shalelike and is regarded as deltaic. Kepferle (1977), in a recent study 

of a siltstone member in the lower part of the group, 

concluded that the siltstone is a turbidite that was 

deposited by west-southwest currents in relatively 

deep water at the base of a deltaic slope. Higher 

members of the group represent associated slope 

and platform deposits. 

Toward the top of the Borden Group are a few 

thin and discontinuous beds of coarsely crinoidal 

limestone. In some places, similar rocks form small 

reefy masses as much as 3 km across and 20 m 

thick. These masses were referred to as bioherms 

by Stockdale (1931) in what was one of the earliest 

applications of the term. Bioherms near Crawfordsville have been known for many years because of 

the abundance and variety of crinoids and other 

fossils that they contain (Lane, 1973). 

Maximum thickness of Borden rocks is about 250 

m near the center of the State, which was an apparent major locus of sediment influx into the Illinois basin. The deltaic siltstone beds which constitute the greater part of the group, dip westward at a 

rate that is significantly greater than the true regional dip. In this way, the siltstones record initial 

dip of at !<east 3 m/km, which is consistent with an 

abrupt westward depositional thinning shown by the 

group. The Borden delta, therefore, is restricted to 

the margin of the basin; in the central part of the 

basin, only about 20 m of prodelta shale represents 

the Borden Group. This classic example of a sediment-starved basin, in which off-delta water depths 

may have reached 300m, was documented by Lineback (1969), who also described the sequence of 

partial basin fills of successive limestone units that 

followed the close of Borden deposition. 
INDIANA K9 

The clay-poor siltstone beds of the Borden Group, 

particularly those in the upper part of the group, 

ar·e resistant to erosion, so that the group is expressed physiographically as scenic uplands of considerable relief, thorough dissection, and steep slopes 

that have many exposures. Equivalent rocks in 

northern Indiana are referred to the Coldwater 

Shale, a greenish-gray slightly silty shale similar to 

the New Providence Shale. This formation is 150 

m thick at the northeast corner of the State and is 

the youngest bedrock in the Indiana part of the 

Michigan basin. 

SANDERS AND BLUE RIVER GROUPS 

The mid-Mississippian limestone sequence-the 

"Barren Limestones" ·of Owen (1859a)-begins at 

the base with a complex succession of microrudites 

and biosparit~es that gradually give way upward to 

packstones and grainstones.a 

These, in turn, are overlain by a thick series of 

micrites that in part ·are fossiliferous and pelletiferous. Low among the micrites are beds of gypsum, 

anhydrit~e, and micritic dolomite. Higher, som.e 

oolites appear, and toward the top· of the sequence 

are thin beds of calcareous sandstone and siltstone 

that presage ·clastic depositional conditions to follow. 

The Sanders Group (fig. 4) is at the base of this 

sequence and includes mainly coarsely textured 

types of limestone; some geode-bearing silty dolomite is interbedded near the base. This gr.oup 

ranges in exposed thickness from about 50 m near 

the Ohio River to a wedge edge in west-central Indiana (Nicoll and Rexroad, 1975). The thinning is 

partly depositional but ultimately is due to truncation beneath Pennsylvanian rocks. Downdip into 

the subsurface, the group thickens abrup·tly as a 

complement to the thinning of the underlying rocks 

that belong to the Borden delta. Thickness as great 

as 140 m has been recorded near the southwest 

corner of the State, where the group includes additional rock units that a~e not present at the outcrop. 

At the top of the Sanders Gr·oup is the famous 

Salem Limestone. This formation is not, as is sometimes stated, an oolite; instead, it is a packstone to 

grainstone composed of sand-sized lime-coated fossil 

fragm!ents. The prominent cross-stratification and 

lack of terrigenous detritus suggest deposition as a 

shallow shoal remote from shore (Carr and others, 

1966). The texture and composition of this rock 

3 Because no scheme of classification yet proposed is fully satisfactory 

for the wide variety of carbonate rock types in the Mississippian System 

of Indiana, selected terms from the classifications of Folk (1959) and 

Dunham (1962) have been used. 

make it ideal for cutting and carving, and for many 

years it has been one of the premier building stones 

of the world (Rooney, 1970). Abundant among the 

microfauna of the Salem is the guide fossil Endothyra (Globoendothy'ta) baileyi (Hall), and in many 

places a diversified but diminutive megafauna is 

found. Especially notably is the Spergen Hill locality, which has been known for more than 100 

years. Early monographic treatments of this fauna 

are those of Whitfield (1882) and Cumings and 

others (1906). 

The Blue River Group (fig. 4) crops out from the 

southern boundary of the State, where the group 

is 150 m thick, northwestward about 200 km into 

west-central Indiana where it is truncated by the 

Mansfield Formation. In the subsurface the group 

is somewhat thicker. It consists mainly of micritic 

limestone, but oolite, sandy limestone (calcarenite), 

and chert of several types are prominent. Associated 

with gypsum and anhydrite in the lower part of 

the group are micritic dolomite and thin beds of 

black, gray, and gre·en-gray shale. The ·evaporite 

deposits are eco·nomically important in the subsurface (French and Rooney, 1969), but they are poorly 

represented on the outcrop. In places in the northern 

part of the outcrop area, beds of limestone breccia 

occur at the evaporite po·sition. 

The gypsum-bearing rocks indirectly give ris·e to 

a group of mineral springs that center on French 

Lick and West Baden, towns. that retain vestiges 

of the era when "taking the waters" was a popular 

pastime. Many other mineral spring localities are 

known, but the major sulfate water springs in Indiana lie nearly •On a north-northwest line within 

about 40 km of French Lick. Along this line the 

gypsum beds lie at a depth of about 100 m. Gypsum. 

and anhydrite are of wide extent downdip from the 

springs, but are thin and sporadic updip·. The interface between the gypsum and the sulfate-:water system is irregular and de·eply embayed. Probably it is 

slowly progressing westward be·cause of the constant removal of gypsum by solution. 

In the upper part of the Blue River Group, true 

oolite is the subdominant lithology. As described by 

Carr (1973), this rock type commonly occurs as 

lenticular bodies about 2 km wide by 6 km long by 

5 m thick. Inner parts of these bodies are composed 

of moderately porous grain-supported oolite; outer 

parts are of less porous oolite that is cemented by 

sparry calcite. Chemically, the rock is an exceedingly 

pure limestone that assays more than 98 percent 

calcium carbonate. In the subsurface, these oolitic 
K10 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

bodies are important reservoirs for petroleum; at 

the surface they are quarried for use as an industrial chemical. As modern analogs, Carr ( 1973) suggested the carbonate sand bodies of shallow marine 

shelf areas in the Bahamas banks. 

WEST BADEN AND STEPHENSPORT GROUPS AND 

UNNAMED UPPER CHESTERIAN GROUP 

Three groups in the upper part of the Mississippian System consist principally of terrigenous 

clastic rocks., and thus they are distinct from the 

underlying mid-Mississippian limestone sequence. 

The lowermost, the West Baden Group (fig .4), is 

about 35 m thick in the outcrop· area (Gray and 

others, 1960). It consists of five formations, three 

of which are clas.tic and include sandstone, shale, 

siltstone, and mudstone, and two of which are biomicritic to oomicritic limestone. N~ear the base of 

the group in the Bethel Formation are beds of shaly 

coal as much as 5 em. thick, the oldest ·coal in 

Indiana. 

Although the limestone formations of the West 

Baden Group are of normal marine origin, they are 

less continuous laterally than might be expected of 

such rocks. Gray and Perry ( 1956) found that in 

places the Reelsville Limestone is absent as the result of facies change. Hrabar and Potter (1969) and 

Sullivan (1972) related similar anomalies to the 

West Baden clastic belt, a branching, irregularly 

linear area 3 to 10 km wide that can be traced from 

the outcrop southwestward for about 80 km and in 

which the limestone formations are replaced laterally by sandstone and other clastic rocks. In a fe·w 

places the transition is abrupt, but more commonly 

jt is gradual and is accompanied by thickening of 

the limestone bed along with increasing content of 

noncarbonate material toward the clastic belt. Strips 

of sandy shale a kilometer or so in width normally 

separate the limestone bed laterally from the axial 

sandstone body. 

The West Baden clastic belt is a distributary of 

Swann's (1963) Michigan Rive·r, an important feature of late Paleozoic geography. The belt marks 

the locus of virtually continuous clastic sedimentation that took pla.ce ·oontemporaneously with deposition of the alternating clastic and carbonate rock 

units that typically are recognized in the West 

Baden Group. The limestone formations were deposited when the rate of clastic supply was regionally diminished, so that clastic dep•osition was limited 

to the distributary belt; the clastic formations represent times when terrigenous sediment was introduced in greater quantity and dispersed more widely. The geographic position of the clastic belt remained stable throughout West Baden time. 

The Stephensport Group (fig. 4) is about 45 m 

thick in the outcrop area (Gray and others, 1960) 

and consists of five formations. The limestone formations, which are more continuous and more prominent in this group than in the West Baden Group, 

include biomicrite, oomicrite, biosparit1e, and oosparite. Among the abundant and varied faunas are 

pentremites (Galloway and Kaska, 1957), crinoids 

(Horowitz, 1965), bryozoans (Utgaard and Perry, 

1960; Perry and Horowitz, 1963), and conodonts 

(Rexroad, 1958; Rexroad and Jarrell, 1961). The 

clastic formations consist of gray shale, siltstone, 

mudstone, and evenly stratified fine-grained sandstone. The sandstone beds also are more continuous 

than those of the West Baden Group· and are notable 

cliff formers, so that the outcrop area of the Stephensport Group includes some of the most rugged 

terrain in southern Indiana. 

The cyclic alterations of clastic- and limestonedominated rock units that typify Chesterian deposition are best shown in the Stephensport Group. In 

general, the clastic units represent marine regresS'ions and the limestone uni.ts represent transgressions. The Big Clifty Formation and the overlying 

Haney Limestone in the middle of the Sibephensport 

Group make up such a regressive-transgressive 

couple. The lower two-thirds of the Big Clifty is an 

evenly stratified fine-grained sandstone of remarkable lateral extent along the outcrop (it is less continuous in the subsurface). It has a wavy upper 

contact that resembles megaripples and is succeeded 

upward in turn by thin. marly mudstone, olive-gray 

and red-brown mudstone and shale, and gray shale 

that toward the top contains increasing numbers 

of fenestrate bryozoans and conularids. This sequence suggests a beach and barrier sand followed 

by a lagoonal mud that finally becomes fully marine. 

The biomicrites, bios:parites, and oosparites of the 

overlying Haney Lim,estone represent a set of closely related shallow marine shelf and shoal environments (Vincent, 1975). Other comparable couples 

among the Chesterian rocks may be similarly, 

though not identkally, interpreted. 

Uppermost Chesterian rocks in southern Indiana 

have been described by Malott (1925) but have received no formal group· na.me. 4 They are here con4 After this paper was submitted for publication, these upper Chesterian rocks were descnbed and their nomenclature was discussed in H. H. Gray, 

1978, Bl!ffalo Wa~low Group-Upper Chesterian (Mississippian) of south- ern Indiana: Indiana Geol. Survey Occasional Paper 25, 28 p. 
INDIANA K11 

sidered an unnamed group that consists mainly of 

shale and that reaches a maximum thickness of 80 

m near the Ohio River. About 70 km to the north, 

however, the group is truncated by the disconformity at the base of the Pennsylvanian System, so 

that areally this is the most restricted of the Mississippian groups. 

This group consists predominantly .of blue-gray, 

green-gray, and olive-gray shale and mudstone in 

which are interspersed a few beds of sandstone and 

many beds of limestone (fig. 4). Some of the limestone beds, which rarely are as much as a meter 

thick, represent tongues of much thicker limestone 

formatioons to the west. A thick and local sandstone 

member near the base of the group forms prominent 

cliffs and box canyons, but for the most part the 

group is topographically expressed as steep, smooth 

slopes beneath caprock ledges of Pennsylvanian-age 

sandstone. Formational terminology that is used for 

equivalent rocks in most of the Illinois basin 

(Swann, 1963) is not applicable here. For a discussion of. some of the problems raised thereby, see 

Shaver and others (1970, p. 175-176). 

Among the limestones of the unnamed group are 

thin beds of micritic dolomite that may indicate a 

sterile penesaline environment, but normal marine 

carbonate and shaly carbonate deposits containing 

bryozoan-brachiopod faunas that have not been 

studied are widely present. Conodont faunas of 

some of the limestones have been described by Rexroad and Nicoll (1965). 

AGE AND CORRELATION OF MISSISSIPPIAN ROCKS 

Many schemes have existed for the subdivision of 

Mississippian rocks by age; the Indiana Geological 

Survey follows the Illinois State Geological Survey 

in the usage (from oldest to youngest) of Kinderhookian, Valmeyeran (formerly Osagean and Meramecian) , and Chesterian for epoch and s~eries terms. 

The Kinderhookian-Valmeyeran boundary is about 

midway in the thin Rockford Limestone,. as shown 

by conodont zonation (Rexroad. and Scott, 1964). 

The Valmeyeran-Chesterian boundary is placed at 

the bas~e of the Paoli Limestone (fig, 4), following 

the reasoning pres·ented by Swann (1963, p. 17-20), 

who based his determination in part on the distribution of Plat1}c?·inites penicillus, a guide fossil found 

in the Ste. Genevieve Limestone, and Tala1·ocrinus, 

which occurs in the Paoli Limestone and in younger 

Chesterian rocks. 

Only a few paleontologic studies of Mississippian 

:nocks in Indiana have attempted correlation with 

the European standard sections. Horowitz and 

Perry (1961) concluded, on the basic of crinoid 

faunas, that the Glen Dean Limestone probably is 

cLose to the Visean-Namurian boundary; from 

studies elsewhere, Mamet and Skipp (1971), on the 

basis of calcareous Foraminifera, would place this 

boundary between the Haney and Glen Dean Limestones. In parts of Europe, the Tournaisian-Visean 

boundary is placed within the zone of Syringothyris. 

In Indiana, this form is found in the Borden Group 

just below the Edwardsville Formation (Cumings, 

1922, p. 493; Stockdale, 1931, p. 191), but on the 

basis of Mamet and Skipp's (1971) criteria, this 

boundary should be placed somewhat higher, probably at the base of the Harrodsburg Limestone. 

THE MISSISSIPPIAN-PENNSYLVANIAN 

UNCONFORMITY 

In the Midwestern United States, rocks of the 

Pennsylvanian System overlie older rocks at an unconformable contact that is second in regional importance only to the unconformity that separates 

Paleozoic from Precambrian rocks. In Indiana, this 

surface is a disconformity-that is, the uneven surface of contact is prominent but the strata above 

and below are virtually parallel. The crenelated line 

of outcrop of this disconformity trends from the 

Ohi.o River in a north-northwest direction some 300 

km to west-central Indiana (fig. 1). The disconformity surface extends from this line southwestward across an area of nearly 19,000 km2 • 

This disconformity has long been recognized as a 

buried ancient land surface that is mostly gently 

rolling, but that is entrenched, in some places quite 

deeply, by a s1et of subparallel valleys that trend 

southwestward entirely across the Illinois basin. 

The shape of this surface in part of Illinois was 

documented by Siever (1951). Similar documentation for Indiana does not exist, but Bristol and 

Howard (1971) prepared a so-called sub-Pennsylvanian paleogeologic map that oovers much of the 

Illinois basin and that strikingly portrays the 

major valleys on the disconformity surface. 

The full scope of the disconformity cannot be appreciated except through subsurface studies, but 

many aspects of it are well displayed on the outcrop. In a railroad cut near Shoals (Gray and others, 

1957, p. 14-16), the disconformity is almost continuously exposed for nearly 300 m and clearly 

shows a small valley with relief of at least 20 m. 

Basal Pennsylvanian rocks here include sedimentary 

iron ore and sandstone, and rest on three formations 

of the Stephensport Group. Similar though less 

striking exposures may be observed at other places 
K12 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

nearby (Gray and others, 1960, p. 29-35). In most 

places, however, the disconformity must be visualized on the basis of scattered data. For example, a 

valley about 35 m deep, 2 to 3 km wide, and more 

than 5 km long was mapped by Malott (1931), using only outcrop data. Quartz pebble conglomerate 

is an important part of the fill in this valley. Some 

of the deepest entrenchment is implied by isolated 

outliers 10 to 20 km from the main outcr.op area 

(Malott, 1946) . These outliers commonly are very 

porous sandstone, and where they rest on limestone 

they probably have been solutionally l·owered, mostly during Cenozoic time, as has a sandstone channelfill associ~ted with the Bethel Formation in Kentucky (Indiana University, 1969). 

North of the Wisconsinan drift boundary (fig. 1), 

the crop line of the Mississippian-Pennsylvanian disconformity is mostly covered, but there also the 

disconformity is a surface of considerable relief 

(Esarey and others, 1950). The valleys of Sugar 

Creek, Raccoon Creek, and their tributaries, most of 

which have been superimposed from a late Wisconsinan (late Pleistocene) drift surface and so have 

created many young valleys having extensive rock 

exposures, show the disconformity well. On a very 

local scale, in walking up the beds of some of these 

creeks, one can cross and recross the MississippianPennsylvanian contact every few steps. Exposures 

in Shades State Park and just downstream along 

Sugar Creek show basal sandstone of the Mansfield 

Formation in contact with the Harrodsburg Limestone and siltstone of the Borden Group. Fifteen 

kilometers downdip to the west is a small inlier of 

the St. Louis Limestone that represents a hill about 

75 m high on the disconformity surface. 

Also observable at the outcrop is the regional 

truncation of the Mississippian rocks by those of 

the basal Pennsylvanian. Youngest Mississippian 

rocks underlie the Pennsylvanian near the Ohio 

River, but northward the disconformity gradually 

slices through 400 m of section. In scattered outliers to the northeast ·Of the north end of the main 

Pennsylvanian outcrop, the entire Mississippian 

column is missing, and Pennsylvanian rocks rest on 

the New Albany Shale. 

Although the disconformity is a profound and 

striking feature wherever it is well expos~ed, many 

of the rocks of the two sys!Uems are not readi1y identifiable with one system or another on a lithologic 

basis alone. Coal of respectable thickness, sedimentary iron ore, and nonstratified gray mudstone and 

clay are indicative .of the Pennsylvanian System and 

biomicrite, biosparite, and red-brown and greengray shale and mudstone are indicative of the Mississippian, but the more common kinds of shale and 

sandstone of the two systems are less distinct. In 

many shales of Pennsylvanian age, however, micas, 

carbonaceous materials, carbonized plant impressions, and siderite nodules are somewhat abundant 

than in otherwise similar rocks of Mississippian age. 

Many Pennslyvanian sandstones are somewhat coarser grained and more micaceous, and contain more 

abundant plant molds than do most Mississippian 

sandstones. Quartz pebbles, which in places are scattered through the basal sandstone beds of the Pennsylvanian System, also are useful indicators. These 

and other criteria were discussed by Atherton and 

others (1960) and Gray (1962). 

The fauna of the youngest Mississippian rocks in 

Indiana clearly indicates an age very close to the 

end of Mississippian time. Somewhat younger 

Chesterian rocks are known from southern Illinois 

(Swann, 1963, p. 42-45; Collinson, Rexroad, and 

Thomp~son, 1971, p. 387-388). In contrast, the oldest 

identified Pennsylvanian florule from Indiana is 

from beds about 30 m above the base of the system 

and is placed by Read and Mamay (1964, p. K6-7) 

at their Zone 4-Zone 5 transition, below which in 

the central Appalachians there is a considerable s·ection of Pennsylvanian rocks. Thus, it appears that 

basal Pennslyvanian rocks in Indiana are somewhat 

to considerably younger than oldest known Pennsylvanian rocks, and that the greater part of the hiatus 

represented by the unconformity belongs to Pennsylvanian time. 

THE PENNSYLVANIAN SYSTEM 

Coal constitutes only about 1 percent of the Pennsylvanian System in Indiana, but its economic impact has caused it to dominate stratigraphic work 

on these rocks since the earliest days of geologic 

research. The three nearly equal parts into which 

the system may be divided, principally on the basis 

of coal content, are more subtle than those of the 

Mississippian, and geologists have not generally 

found it useful to er~ect a semiformal class.ification 

such as that once used in the northern Appalachians 

in which "productive" and "barren" measures alternate. Nevertheless, a "productive" part of the 

system, which is Desmoinesian in age and which includes the thickest and most extensive beds of coal 

and widespread beds of limestone as well, may 

rather readily be identified (fig. 5). Below this, in 

rocks of Morrowan and Atokan age, sandstone is 

·somewhat more prominent than in the rest of the 
INDIANA K13 

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a: 

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300 

200 

100 

Mattoon 

Formation 

Bond 

Formation 

Patoka 

Formation 

Shelburn 

Formation 

Dugger 

Formation 

Petersburg 

Formation 

Linton 

Formation 

Staunton 

Formation 

Brazil 

Formation 

Mansfield 

Formation 

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FIGURE 5.-Columnar section showing exposed Pennsylvanian 

rocks in Indiana. 

system, and beds of coal and limestone are relatively thin and discontinuous. Above, in rocks of late 

Desmoinesian and Missourian age, shale is the 

dominant rock type, and only thin and local beds of 

coal and limestone are found. Rocks of latest Missourian and Virgilian age are not found in Indiana. 

Formational nomenclature was slow to be applied 

to the Pennsylvanian rocks of Indiana (fig. 3), and 

even today is not applied strictly in accord with the 

precepts set forth in the Code of Stratigraphic 

Nomenclature, which calls for successive formations 

to be lithologically homogeneous and distinct one 

from another (American Commission, 1970, Art. 

6). Contributing to this state of affairs are the following factors. First, by far the greater part of 

the Pennsylvanian System consists of a somewhat 

limited variety of common clastic rock-types-a few 

kinds each of sandstone, siltstone, shale, and clay. 

Truly distinctive lithologies are few. Second, the 

clastic rocks are interspersed with coal, limestone, 

chert, and sedimentary iron ore in repetitive cyclic 

sequences. Sequences that are seemingly identical 

may in fact be far apart stratigraphically. Third, 

lateral facies changes may be abrupt. Within short 

distances, individual beds and whole cyclic sequences 

may change in character so completely that they 

are scarcely recognizable. In consequence~ formations in the Pennsylvanian System in Indiana are 

defined with reference to thin beds of coal and limestone used as key beds. As a further complication 

to traditional stratigraphic study, floral and faunal 

distributions are strongly facies controlled, so that 

fossil sequences that are effective for age determination or interregional correlation are sparse. These 

difficulties are shared with equivalent rocks both in 

the Appalachians, where the Pennsylvanian System 

has a more continental aspect, and in the midcontinent, where marine sequences are better developed. 

RACCOON CREEK GROUP 

Rocks that constitute approximately the lower 

one-quarter of the Pennsylvanian System in Indiana 

are assigned to the Racoon Creek Group (fig. 5). 

This group is extremely variable in thickness, 

primarily as a result of the disconformable relationship at its base. In the northern part of the outcrop 

area (fig. 1), the Raccoon Creek Group is 30 to 

100 m thick (Hutchison, 1961) ; at the southern 

edge of the outcrop belt it is 150 to 200 m thick 

(Hutchison, 1959, 1971a) ; and in the subsurface 

at the southwest corner of the State, it is 300 m 

thick (Shaver and others, 1970, p. 137). Most of 

the increased thickness results from additional beds 
K14 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

at the base of the group. Thus, beds in the lower 

part of the group in the southern outcrop area are 

not found to the north, and beds near the base of 

the group in the subsurface are not represented on 

the outcrop. 

The lower part of the Raccoon Creek Group is 

designated the Mansfield Formation (fig. 5). Most 

of the variation in thicknes,s shown by the group is 

assignable to this formation. As described from outcrop data (Gray, 1962), about 60 percent of the 

Mansfield Formation is sandstone, mostly evenly 

stratified to cross stratified; 22 percent is gray 

shale, and 14 percent is siltstone, mudstone, and 

clay. The rest includes small amounts of black shale, 

coal, limestone, chert, and sedimentary iron ore. 

Many of the sandstones are somewhat coarser 

grained and texturally less mature than those in the 

Mississippian formations. They contain significant, 

though small, amounts of clay as grain coatings, as 

matrix, and as discrete sand-size grains, some of 

which appear to be clots or aggregates and some of 

which probably are degraded shale fragments. Many 

of the sandstone beds are prominent cliff-formers, 

but most of the other rocks are less well exposed. 

In the lower part of the Mansfield Formation near 

French Lick are beds of clay-bonded, slightly friable 

siltstone that are characterized by an exceptional 

smooth and uniform stratification. These rocks, 

which are used to make sharpening stones and are 

known as the Hindostan Whetstone Beds, cleave so 

perfectly that in quarrying they oommonly are 

lifted out, by wedging, in sheets about 0.5 m wide 

by 2 m long by 2 em thick. From their earliest use 

in 1821, some whetstones were exported to Europe 

(Carr and Hatfield, 1975, p. 11), but production 

now has almost ceased, and stratigraphic interest in 

the whetstones overshadows their ec·onomic value. 

Extending over an area of 20 km along strike by 5 

km wide, in a zone about 15 m thick and marked 

above and below by thin but traceable beds of coal 

(Gray and others, 1960, p. 24-27), this unique 

lithology long has invited environmental interpretation as a lacustrine, lagoonal, or flood-plain deposit. In addition to the varvelike stratification, 

evidence includes a variety of delicate tracks and 

trails (Owen, 1859b, p. 17; Gray, 1962, p. 14), an 

assemblage of fossil plants (Kindle, 1896, p. 354-

355), and large standing stumps of Lepidodendron 

(Kindle, 1896, p. 349-350). 

Maps and other regional interpretations by Wanless (1955; 1975, p. 75) imply that the Hindostan 

Whetstone Beds constitute an isolated unit that is 

older than any other Pennsylvanian deposit in the 

Illinois basin. Although these beds contain a flora 

that apparently is older than any other Pennsylvanian flora yet studied in the basin, the beds are 

not an isolated occurrence. Rocks stratigraphically 

equivalent to the whetstone and to the marker beds 

of coal above and below have been traced northward for a few kilometers to where they are terminated by a facies change, and southward about 

60 km to the Ohio River (Gray, 1962, p. 31). In 

the subsurface, where equivalent beds have been 

widely recognized (Hutchison, 1964, 1967, 1971b), 

they are underlain by 40 m or more of Pennsylvanian rocks. Included among these older rocks are 

a few beds of coal. The floras of this part of the 

Pennsylvanian System have not been studied, and 

probably among them are floras as old as the flora 

of the Hindostan Whetstone Beds, or older. 

The principal producing beds of coal in the Racooon Creek Group are those of the Brazil and Staunton Formations (fig. 5). Although local in extent 

and commonly no more than a meter thick, these 

have been mined by both underground and stripping methods. The Lower and Upper Block Coal 

Members of the Brazil Formation are of special 

interest. These are nonagglome,rating and low in 

sulfur content, and their ash has a high fusion 

point. These properties placed them in demand for 

blacksmithing from the time of their discovery, 

about 1850. By 1870, the Block coals were being 

used as a direct charge in six Indiana blast furnaces, but by 1895 the last of these had ceased operation (Wayne, 1970) and these coals were then relegated mainly to domestic use. Also in the Brazil 

Formation, a waxy cuticular "paper coal" has been 

reported (Neavel and Guennel, 1960). 

Many of the coal beds in the Staunton Formation 

are associated with marine deposits and characteristically have a relatively high sulfur content (Wier, 

1973, fig. 9). The bed that marks the top of this 

formation and of the Raccoon Creek Group, the 

Seelyville Coal Member (fig. 5) , is the lowest of the 

five most continuous and most productive beds of 

coal in Indiana. 

CARBONDALE GROUP 

Four of the five most productive beds of coal in 

Indiana are included in the Carbondale Group (fig. 

5) . Along the outcrop this group does not vary 

much from its average thickness of about 100 m, 

although the three formations that make up the 

group are themselves quite variable. These formations are, in ascending order, the Linton, Petersburg, and Dugger Formations. Each is bounded at 
INDIANA K15 

the top by a widespread and thick bed of coal that 

is stratigraphically defined as a member (fig. 3). A 

few of the less extensive beds that are of stratigraphic importance also are defined as members. 

The Carbondale Group extends across southwestern Indiana from the Ohio River north-northwestward to the Illinois Staibe line just north of Terre 

Haute (fig. 1). This belt of outcrop fairly well defines the area of intensive strip mining (Powell, 

1972) ; areas of underground mining lie within and 

west of the outcrop belt. Of the 1.3 x 10° metric tons 

of coal that has been produced in Indiana through 

1970, nearly 90 percent has come from the Carbondale Group (Wier, 1973). 

The Linton Formation ranges from 15 to 40 m 

in thickness, and averages about 25 m (fig. 5). This 

variation is due partly to sandstone lenses, which 

in places are as thick as 20 m, near the base of 

the formation. Closely overlying the sandstone, or 

overlying gray shale or clay where the sandstone is 

absent, is the Colchester Coal Member (fig. 3), a 

thin but widespread bed that is an important stratigraphic marker both in Illinois and in Indiana. 

Other major Indiana coals, notably the Seelyville 

and Survant Coal Members (fig. 3), are absent or 

are less well represented in Illinois. 

Just above the Colchester Goal Member is one of 

two thin black shale beds that have been the 

object of probably the most intensive study of Pennsylvanian paleoenvironm.ental conditions in the Illnois basin. Zanger! and Richards.on (1963), primarily in search of exquisitely preserved vertebrate 

remains (notably sharks), painstakingly excavated 

three sites, stratum by stratum. One of these sites 

was in the black shale overlying the Colchester 

Coal Member ; the other two were in an older black 

shale in the Staunton Formation. These authors 

perceived the black shale environment as mainly 

shallow-water lagoonal, influenced by adjacent delta 

and shoreline sedim,entation, and toxic, not as much 

a result of salinity variations (from marine to 

brackish to fresh) as it was a result of the presence 

of a flotant, a floating mat of vegetation that inhibited wave action and that contributed to anaerobic 

conditions in the water beneath it. The varied faunas 

appear to be death a·ssemblages; animals floated or 

swam from more favorable environments associaked 

with open water west of the studied sites into the 

restricted environments, where they died. Decay was 

slight and burial was swift. 

The Petersburg Formation (fig. 5) is 25 to 50 m 

thick and averages about 35 m. It consists principally of shale and sandstone and includes at its 

top the Springfield Coal Member, from which for 

many years has come about half of the coal produced 

in Indiana (Wier, 1973, p. 28). Commonly, this member is 1 to 2m thick, but it attains 4 m in one small 

area (Shaver and others, 1970, p. 170). Like most 

Indiana coals, it is bright-banded high-volatile bituminous coal. Its heating value on an as-received 

basis typically is about 6,400 calories per gram, and 

its ash content is about 10 percent. Because its average sulfur content is just over 3 percent (Wier, 

1973, p. 14), recent exploratory effort has .been directed toward defining areas of lower sulfur. The 

Springfield Coal Member commonly has a marine 

shale roof, but where the roof rock is nonmarine, 

the sulfur content of the coal is relatively low. Coal 

balls from this member contain beautifully preserved plant materials (Benninghoff, 1943) ; some 

also contain a marine invertebrate fauna (Boneham, 

1976). 

The Dugger Formation (fig. 5), which ranges 

from 25 to 50 m and averages 40 m in thickness, 

includes four named lim·estone members and four 

named coal members (Shaver and others, 1970, p. 

49). The Alum Cave Limestone Member near the 

base of the formation is a widely traceable marine 

marker bed, but the other limestones appear to be 

of limited areal extent. Near the middle of the formation are two thin coal members, one of which 

probably is equivalent to the Herrin Coal, a principal mined coal in Illinois; neither of thes•e beds is 

presently commercial in Indiana, however. The 

Hymera and Danville Coal Me·mbers in the upper 

part of the formation are widely recognized in the 

northern part of the Indiana coalfield and are 

thought to be equivalent to two beds, locally called 

the Lower and Upper Millersburg Coals, in the 

southern part of the field (Shaver and others, 1970, 

p. 41-42, 74-75). The correlation is uncertain because continuity of the beds is interrupted by a belt 

of clastic sediments that probably is contemporaneous with coal dep·osit1on. Some of the underlying beds, notably the Springfield Coal Member, also 

are discontinuous in the same area, and thus the 

clastic belt may represent a persistent route of sediment transport into the Illinois basin. The margins 

of the clastic belt are marked by splits, cutouts, and 

changes in the character of the coals. 

McLEANSBORO GROUP 

The upper part of the Pennsylvanian System in 

Indiana, constituting more than half of the system 

in rock thickness, has been something of an enigma 

to stratigraphers. The area of outcrop in southwest-
K16 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

ern Indiana is thickly loess covered, so that expos-~ 

ures are few and far apart; faulting and rapid 

southward thickening of the formations complicate 

geologic interpretation; and the rocks are not productive of coal or other economic minerals that 

would provide impetus for study. In earlier work, 

serious misoorrelations were made, notably in respect to the Merom Sandstone Member (fig. 3). The 

definitive study of these rocks is a doctoral dissertation (Wier, 1955) that has not been published, but 

conclusions from this study have been incorporated, 

with emendations as required by newer data, into 

the current "Compendium of Rock-Unit Stratigraphy 

in Indiana" (Shaver and others, 1970), and that 

volume is the basis for much of the discussion pre- I 

sented here. 

All the rocks in the Pennsylvanian System above 

the top of the Danville Coal Member of the Dugger 

Formation are assigned to the McLeansboro Group I 

(fig. 5), which consists, in ascending order, of the 

Shelburn, Patoka, Bond, and Mattoon Formations. 

The full thickness of the group in the central part 

of the Illinois bas:in is about 400 m, but in Indiana 

its maximum known thickness is 250 m. 

The Shelburn Formation (fig. 5) is the most 

widely p~res'ent and best known formation in the 

McLeansboro Group. It can be traced from near 

Evansville on the Ohio River to the Illinois State 

line a little north of Terre Haute (fig. 1). Its thickness ranges from 20 to 80 m and averages about 45 

m. A thick sandstone member is present in places 

near its base; the re,st of the formation consists 

principally of shale and siltstone and includes thin 

and discontinuous beds of coal. The West Franklin 

Limes,tone Member at the top of the formation is an 

important marker bed in Indiana and consists of 

one to three thin beds of limestone separated by 

shale. Total thickness of this member is about 5 m. 

In Illinois, according to Willman and others (1975, 

p. 167, 194), the West Franklin m'ember is represented by three or more named members that span 

the lower half of the M~odesto Formation. 

The Patoka Formation is recognized in six counties in southwestern Indiana, but in most of this 

area it is the youngest Pennsylvanian formation 

and is not present in its full thickness. Where the 

entire formation is fiound, it is 30 to 50 m thick. 

Bounded at the bottom by the top of the West 

Franklin Limestone Member and at the top by the 

base of the Shoal Creek Limestone Member (fig. 3), 

the Patoka Formation consists principally of shale 

but includes several named __ sandstone, limestone, and 

coal members. Earlier miscorrelations of some of 

these members now have been corrected (Wier, 

1955; Wier and Girdley, 1962). Most of these members are of limited areal extent; only one, the Inglefield Sandstone Member near the base of the formation, is recognized in Illinois (Willman and others, 

1975, p. 196), where rocks equivalent to the Patoka 

Formation are assigned to the upper part of the 

Modesto Formation. 

The Bond Formation (fig. 5) includes rocks between the base of the Shoal Creek Limestone Member and the top of the Livingston Limestone Member (fig. 3), both of which are important marker 

beds throughout much of the Illinois basin. This 

forma-tion consists principally of shale and siltstone 

but includes one named sandstone m1ember near its 

base and also contains one thin coal member and 

one limestone member. Because of faulting and 

erosion, the entire f,ormation is present in Indiana 

in only two rather limited and widely separated 

areas. Its thickness is about 45 m (Shaver and 

others, 1970, p. 20). The formation has a wide distribution in Illinois, where many members are 

recognized that have not been identified in Indiana. 

All Pennsylvanian rocks in Indiana above the top 

of the Livingston Limestone Member are assigned 

to the Mattoon Formation. Near the base of this 

formation is a prominent sandstone, the Merom 

Sandstone Member (fig. 3). Nearly all the thick 

sandstone m1embers in the McLeansboro Group have 

at one time or another been identified as the Merom 

(see, for example, Malott, 1948) ; this member is 

now known to be present in Indiana only near the 

type locality in western Sullivan County and in the 

Mumford Hills area in northwestern Posey County 

(Wier, 1960; Shaver and others, 1970, p. 109). In 

the former area only about 12 m of the Mattoon 

Formation is pres,ent; in the latter area the formation rea~ches its maximum thickness in Indiana 

of about 45 m. These are the youngest Pennsylvanian rocks, and the youngest bedrock, in Indiana; 

somewhat younger rocks are present in Illinois 

where the Mattoon Formation reaches its maximum thickness of nearly 200 m near the center of 

the Illinois basin (Willman and others, 1975, p. 198). 

AGE AND CORRELATION OF PENNSYLVANIAN ROCKS 

Although plant megafossils have been reported 

fDom Pennsylvanian rocks in Indiana since the days 

of Owen (1859a, p. 43), f,ew definitive studies have 

been made. Collections reported by Lesquereux 

(1880), C. D. White (in Kindle, 1896, p. 354-355), 
REFERENCES CITED K17 

Jackson (1917), and Benninghoff (1943) constitute 

nearly all the earlier work. An overvi~ew by Canright 1959) summarized the earlier studies and 

briefly listed genera recognized from 93 collecting 

sites. In the most thorough study yet published, 

Wood (1963) reported 86 species in a single flora 

from the Brazil Formation ; both late Pottsvillian 

e:11nd Alleghenian forms were included, however, and 

after extensive discussion of the distribution of 

many of the taxa elsewhere, Wood concluded (p. 

28-30) that the fl.ora cannot be used for precise age 

determination. Similarly, Read and Mamay (1964, 

p. K7) indicated that the flo·ra of the Hindostan 

Whetstone Beds is transitional between their floral 

zones 4 and 5. Thus, the value of plant megafossils 

for precise age determination has not yet be1en 

established in the Pennsylvanian System of Indiana. 

Miospores fr:om the coal beds were studied by 

Guennel (1952, 1958), who was convinced of their 

value in correlation, at least on a local basis, and 

who also suggested some regional correlations. He 

did not, however, attempt to design a zonal scheme 

or to assign standard age designations. 

Whereas floral studies look eastward to the Appalachian area, faunal studies look wes.tward to the 

midcontinent. Fifteen limestone members are named 

in the Pennsylvanian System of Indiana, and nearly 

all thes1e contain marine invertebrate macrofossils 

or microfossils. Again, however, definitive studies 

are few, but some success in age determination and 

interregional correlation has been achieved through 

study of the microfauna of some of the older limestones. St. Jean ( 1957), on the basis of a foraminiferal faunule, established an early Desmoinesian 

age for a limestone in the Staunton Formation. 

Thompson and Shaver (1964), considering both 

fusulinids and ostracodes, suggested a correlation 

with type Morrowan rocks for several limestone 

beds in the upper part of the Mansfield Formation. 

Shaver and Smith (1974) confirmed both the above 

correlations and assigned the Brazil Formation, 

mostly by default of definitive faunas, to the Atokan 

Series. Microfossils from higher Pennsylvanian 

limestone beds have not been studied, hut megafossils were listed by Wier (1955), who concluded 

(p. 64) that the West Franklin Limestone Member 

probably is latest Desmoinesian in age. 

No definitive. studies relating the Pennsylvanian 

rocks of Indiana to European standard sections have 

been made. The age assignments in European terms 

shown in figure 3 follow the p·rovisional correlations 

presented by McKee (1975, p. 2). 

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---1909, Supplementary report to the report of 1898 on 

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Atherton, Elwood, and others, 1960, Differentiation of Caseyville (Pennsylvanian) and Chester (Mississippian) sediments in the Illinois basin: Illinois State Geol. Survey 

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Benninghoff, W. S., 1943, Preliminary report on a coal 

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52, p. 62-68. 

Blatchley, W. S., 1897, Introductory: Indiana Dept. Geology 

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K18 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

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---1972, Geologic map of the 1 o X2o Louisville Quadrangle, Indiana, showing bedrock and unconsolidated 

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Gray, H. H., Wayne, W. J., and Wier, C. E., 1970, Geologic 

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40 p. 

---1958, Miospore analysis of the Pottsville coals of 

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1148-1153. 

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---1904, Geological map of Indiana: Indiana Dept. 

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miles equals 1 inch. 

Hopkins, T. C., and Siebenthal, C. E., 1897, The Bedford 

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K20 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

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Fieldiana-Geology Mem., v. 4, 352 p. 
The Mississippian and Pennsylvanian 

(Carboniferous) Systems in the United StatesIllinois 

By ELWOOD ATHERTON and JAMES E. PALMER 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1110-L 

Prepared in cooperation with the 

Illinois State Geological Survey 

Historical review and summary of areal, 

stratigraphic, structural, and economic 

geology of Mississippian and 

Pennsylvanian rocks in Illinois 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1979 

FIGURE 1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

11. 

12. 

13. 

14. 

CONTENTS 

Page 

~bstract ----------------------------------------------------------------- L1 

Introduction ------------------------------------------------------------- 1 

The Mississippian System ------------------------------------------------- 1 

Stratigraphy --------------------------------------------------------- 4 

Kinderhookian Series -------------------------------------·-------- 4 

Valmeyer an Series _____________________________ ---------- _ _ __ _ ___ 6 

Chesterian Series ------------------------------------------------- 12 

Paleontology --------------------------------------------------------- 16 

Environment of deposition -------------------------------------------- 17 

Tectonic development ------------------------------------------------- 18 

Economic products _________ -- __________ - ---- ____ ---------------------- 19 

The Pennsylvanian System ------------------------------------------------ 21 

Boundaries of the Pennsylvanian System ------------------------------- 22 

General characteristics of Pennsylvanian strata ------------------------- 22 

Stratigraphy --------------------------------------------------------- 22 

~bsaroka Sequence ----------------------------------------------- 22 

Morrovvan Series ------------------------------------------------- 22 

~tokan Series ---------------------------------------------------- 25 

Desmoinesian Series ---------------------------------------------- 30 

Missourian Series ------------------------------------------------ 32 

Virgilian Series _ ------------------------------------------------- 32 

Cyclothems in Illinois stratigraphy ------------------------------------ 35 

Paleontology --------------------------------------------------------- 35 

Morrovvan Series ------------------------------------------------- 35 

~tokan Series ---------------------------------------------------- 37 

Desmoinesian Series ---------------------------------------------- 37 

Missourian Series ___________________ ------ __ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ 38 

Virgilian Series _ _ _ __ _ _ _ _ __ _ _ _ _ __ _ ___ _ _ _ __ _ _ _ _ _ _ _ _ _ __ _ _ __ _ _ _ _ _ _ __ _ 38 

Environments of deposition -------------------------------------------- 38 

Tectonic development ------------------------------------------------- 40 

Economic products __ ------------------------------------------------- 41 

References cited ---------------------------------------------------------- 41 

ILLUSTRATIONS 

Counties of Illinois ------------------- __ -----------·--- _________________ ;_ _______________________ _ 

~real extent of the Mississippian System --------------------------------------------------------- Columnar section of Kinderhookian Series __________________________ ;. _______ -------- _____ ----- ____ _ 

Thickness of Kinderhookian Series --------------------------------------------------------------- Thickness of Valmeyeran Series ____________________________________________________ ------ ______ _ 

Columnar sections of Valmeyeran Series ---------------------------------------------------------- Cross section shovving Borden Siltstone delta ___________________________________________ ----- ______ _ 

Thkkness of Chesterian Series -------------------------------------------------------------------

Columnar section of Chesterian Series ------------------------------------------------------------ Paleogeography during Chesterian sedimentation ________________________________________________ _ 

Major tectonic features of Illinois ______________________________________________________________ _ 

Development of classification of Pennsylvanian System ·---------------------------------------------

Paleogeologic map of sub-Pennsylvanian Chesterian surface ----------------------------------------

Thickness of Pennsylvanian System --------------------------------------------------------------

m 

Page 

L2 

3 

4 

5 

7 

8 

10 

13 

14 

18 

20 

21 

23 

24 
IV 

FIGURE 15. 

16. 

17. 

18. 

19. 

20. 

21. 

22. 

CONTENTS 

Classification of Pennsylvanian System __________________________________________________________ _ 

Extent of Caseyville Formation ______________ ----- ______________________________________________ _ 

Combined thickness of Caseyville, Abbott, and Spoon Formations ----------------------------------- Thickness of Carbondale Formation ______________________________________________________________ _ 

Thickness of Modesto Formation _ ------------------- _______ --------------------------------------

Thickness of Bond Formation -------------------------------------------------------------------- of Mattoon Formation ________________________________________________________________ _ 

Arrang-ement of lithologic units in a cyclothem -----------------------------------------------------

Page 

L26 

28 

29 

31 

33 

34 

36 

37 
THE MISSISSIPPIAN AND PENNSYLVANIAN (CARBONIFEROUS) 

SYSTEMS IN THE UNITED STATES-ILLINOIS 

By ELWOOD ATHERTON1 and JAMES E. PALMER1 

ABSTRACT 

The Carboniferous equivalents in Illinois consist of two 

systems separated by an angular unconformity. The Mississippian System includes 40 formations grouped into 3 series. 

It is more than 975 m thick in southern Illinois and thins 

northward. Limestone is the dominant rock type. During 

formation of the sub-Pennsylvanian unconformity, valleys 

as deep as 140 m were cut in the top of the Mississippian. 

The Pennsylvanian System includes about 140 named members, grouped into 7 formations and 5 series, and is about 

760 m thick, it has a maximum composite thickness of more 

than 1,000 meters. About half of the system is shale and twofifths is sandstone and siltstone; extensive coal seams are 

a distinctive feature. A great thickness of rock was eroded 

during formation of the unconformity on the top of the 

Pennsylvanian. In the Mississippian, invertebrate fossils 

abound in most of tRe limestone and calcareous shale; in the 

Pennsylvanian, plant fossils are abundant in the coal and 

shale, and marine invertebrate fossils in the limestone. The 

Mississippian includes a siltstone delta built out into fairly 

deep water (about 300 m), but most of the strata were 

deposited in relatively shallow water. During the Pennsylvanian, the surface fluctuated above and below sea level, 

and ·extensive coal swamps formed at a number of horizons. 

The major tectonic event during the Carboniferous in Illinois was the subsidence of the autogeosynclinal Illinois 

basin; the maximum subsidence centered near the southern 

tip of the State. Oil in the Mississippian and coal in the 

Pennsylvanian are the major economic products. 

INTRODUCTION 

The Carboniferous ·equivalents in Illinois ·consist 

o.f the Mississippian and Pennsylvanian Sy.stems. 

The Mississippian is estimated to consist of about 

35 ·percent .sha:le and siltstone, 10 percent sandstone, 

and 55 percent limestone and dolomite, nearly all 

deposited in a shallow marine environment. The 

Pennsylvanian is estimated to consist of about 50 

percent shale, 40 percent sandstone and siltstone, 5 

percent limestone, 1 to 2 :percent coal, and the remainder, .including siderite and chert, less than 1 

percent. The environment alternated from marine 

to nonmarine in many cycles, and extensive coal 

1 Illinois State Geologico! Survey, Urbana, Ill., 61801. 

swamps are a distinctive feature, particularly dur-

.ing the Pennsylvanian. The two systems are differentiated in Illinois not only by the overall character 

of their sediments and fossils, but also by the angular unconformity that sep·arates them. 

Illinois, an area of 146,020 km2 , is divided into 

102 counties (fig. 1), surveyed on a rectangular 

grid system q,f townships. The stratigraphy of Illinois 1is summarized in Willman and others (1975), 

which is the source of most of the information and 

illustrations given here. The literature of Illinois 

geology through 1965 is indexed in Willman and 

others ( 1968) . 

The stratigra·phic nomenclature used in this paper 

has not been reviewed by the Geologic Names Committee of the U.S. Geological Survey. The nomenclature used here conforms with the current usage of 

the Illinois State Geological Survey. 

THE MISSISSIPPIAN SYSTEM 

The Mississippian System is named for exposures 

that extend for about 650 km in the Mississippi 

River val.ley along the western margin of Illinois. 

Mississippian rocks occur .in the ·subsurface over 

the southern two-thirds o.f the State, where they 

are overlain mostly by Pennsylvanian rocks. In the 

western part of the State, the Mississippian rocks 

are covered by glacial till, and in southernmost Illinois, they are concealed by Cretaceous gravel and 

sand. Outcrops occur mainly in the bluffs of the 

Mississippi, Illinois, and Ohio Rivers that border 

and bisect the State. 

The Mississippian System attains a thickness of 

·a little more than 975 m in southern Illinois (fig. 

2). Northward thinning is partly due to deposition 

and is partly the result of erosional truncation during formation of a prominent sub-Pennsylvanian 

unconformity. During Mississippian time, the Illinois basin was open so.uthward between the Ozark 

and Nashville positive areas so that many formaL1 
L2 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

~ ~ ~ -----,---r---lf--,-----r-r 

1 I 2! 3 14! 5 i6 

_ _j_l _ _l_-,__l_lT __ j_ __ 

42° -~ j 8 l I ~- ~ 1---'""l"'"- - -i 11 I 12 1 ,3 1 

s ! 10 L ~--t-l.J 14 

,J--T_j_ __ -r-- -~ 21 \ -l._l : 

/ I I r------1 23 '"-l 

15 I I 18 I I I ---~ 17 I -~ 20 22 I r -----, 

~--1_]--l---J~:l .--j_- r--J 32 \ 

--1 I ~ 28 : I I I 

I

I II 26 r-- -7---_l~ 31 IT ___ I 

24 I 25 I i 29 (__.., 30 l--- II I 33 : 

l _r---~ / . _j l I I I .- T -- I '-1 I Ll-,_,..1 T __ ..J I 

I

I 35 I 36 ,r---- 37 i 38 I 39 L_l-----l 

34 r·· I r-----; I ___ j----{_ ;' 44 ~---Lr-----,~~ l : 

r

' - 42 ~-7-~,.-- ,_,.,.,J 46 Ll 47 j II 49 II 50 I \ , __, I I ---1 

40 L' 41 'i-~--~~:JLL_'--~ I 48 L---~---~J I -~ 1 r-- 56 1 • -~ ----....~ t~· , 54 _r- 1 r--t 5s ~ : l 53 \ I I I ,...-1' 59 I 51 \52 L, 1 ~ ~--t 57 ~----

r--Li1 _l __ r-i 55 I 1-....._j 65 ~--[: 60i 61 I I' L __ - ....--~ 64 ~----1 I ~ l I 66 I 67 

y-.,-_rrl 62 j· 63 I --~---L.---~--- \ 68 I I I II I I 

r-l ____ _Lrr--1 71 , 72 I 73 • 74 

L 70 II LT ____ ll I 

69 I I ,.-----' 1-----lr---

-----.-j----J...-j 76 1 11 r 1a i 79 

I 75 i ~----<..---.__+--

\, so ~---../--~---~ 83 la4)B5 

·,_ I 81 I 82 I I ) 86 ( _l J r· __ l __ J....__ r--- -r----

. 87 i 88 ~----~1 90 i 91 I ) 89 I 

)------1 _j----L-

, 92 ,-93- i 94 l 95 

~-j_-.---+--.L-, 50 100 KILOMETERS • 96 l 97 i 98 I 99 

Adams 40 

Alexander 100 

Bond 70 

Boone 4 

Brown 41 

Bureau 18 

Calhoun 60 

Carroll 7 

Cass 43 

Champaign 49 

Christian 55 

Clark 67 

Clay 77 

Clinton 75 

Coles 65 

Cook 14 

Crawford 74 

Cumberland 66 

De Kalb 11 

De Witt 47 

Douglas 58 

Du Page 13 

Edgar 59 

Edwards 84 

Effingham 72 

Fayette 71 

Ford 39 

Franklin 89 

Fulton 36 

Gallatin 95 

Greene 61 

Grundy 22 

Hamilton 90 

Hancock 34 

Hardin 99 

Henderson 24 

Henry 17 

Iroquois 33 

Jackson 92 

Jasper 73 

Jefferson 82 

Jersey 68 

Jo Daviess 1 

Johnson 97 

Kane 12 

Kankakee 32 

Kendall 21 

Knox 26 

Lake 6 

La Salle 20 

Lee 10 

Livingston 31 

Logan 46 

McDonough 35 

McHenry 5 

Mclean 38 

Macon 56 

Macoupin 62 

Madison 69 

Marion 76 

Marshall 28 

Mason 44 

Massac 102 

Menard 45 

Mercer 16 

Monroe 86 

Montgomery 63 

Morgan 53 

Moultrie 57 

Ogle 8 

Peoria 29 

Perry 88 

Piatt 48 

Pike 51 

Pope 98 

Pulaski 101 

Putnam 19 

Randolph 87 

Richland 78 

Rock Island 15 

St. Clair 80 

Saline 94 

Sangamon 54 

Schuyler 42 

Scott 52 

Shelby 64 

Stark 27 

Stephenson 2 

Tazewell 37 

Union 96 

Vermilion 50 

Wabash 85 

Warren 25 

Washington 81 

Wayne 83 

White 91 

Whiteside 9 

Will 23 

Williamson 93· 

Winnebago 3 

-""\--l .. -r--~ 1 00 (1 01 1 02 ' 

' '\ ~ I 

Lawrence 79 Woodford 30 

FIGURE !.-Counties of Illinois. 
ILLINOIS 

EXPLANATION 

-600- Isopach-contour interval 

60 meters 

[!i!i!i!i!~!~!~!~!~!~!~!l Outcrop area 

l=rr~:~:r~~ Subcrop area (Top eroded beneath :·:·:·:·:·:·:·:·:· Pennsylvanian or, in south, 

Cretaceous rocks) 

E Eroded 

OC:::::Ee==--3=:::~2i:O==:JE=3=::::340 MILES 

0 20 40 KILOMETERS 

E3 E3 

FIGURE 2.-Areal extent of the Mississippian System in Illinois. Thickness is shown where upper Chesterian 

strata are present (Willman and others, 1975). 

L3 
L4 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

tions originally· thickened southward well beyond 

theri·r present extent. Post-Mississippian uplift 

closed off the Illinois basin on the south, however, 

and erosion truncated the uptilted strata in southernmost Illinois. 

In Illinois, the system is divided into three series. 

The lowermost, the Kinderhookian, consists mainly 

of normal marine fine-grained clastic sedimentary 

rocks. The ~relatively thick Valmeyeran, in the 

middle, includes biogenic limestone along the outer 

edges of the ba.s:in in western and nor·thwestern 

Illinois but is represented by a thick siltstone delta 

in southwestern and ·central-eastern Illinois. The 

Chesterian Series, at the top, is thick and ·consis~ts 

of limestone-shale and sandstone-shale formations 

that represent deltaic sediments deposited in p·atterns that are transitional to the cyclothems of the 

Pennsylvanian. Between the Mississippian and the 

Pennsylvanian is a major unconformity where valleys as deep as 135 m have been -cut into Chesterian 

sedimentary rocks. 

Fossils are abundant .in the M~ississippian. Productid and spiriferid brachiopods are useful for biostratigraphic zonation of much of the sy.s.tem. Blastoids, crinoids, and calcareous foraminifers provide 

a practical basis for correlation of Valmeyeran and 

Chesterian strata, and conodonts are the basis for 

biostratigraphic zonation throughout ·the system. 

Tectonic activity, associated mainly with the 

Ozark uplift, controlled depositional patterns of the 

Kinderhookian and closed the epoch with broad uplift in western Illinois. Shallowing of the seas during 

Valmeyeran and Chesterian time culminated with 

widespread post-Mississippian erosion. 

STRATIGRAPHY 

KINDERHOOKIAN SERIES 

The Kinderhookian Series consists mainly of silty 

marine shale overlain by the widespread Chouteau 

Limestone (fig. 3). The series, only 50 m thick at 

its maximum in western Illinois, is very thin in the 

eas·tern and southern parts of the Illinois basin 

(fig. 4). The shale of the Kinde·rhookian is combined 

with that of the underlying Devonian to constitute 

the New Albany Group. The base of the series 

commonly occurs within the shale sequence and can 

be identified only by paleontolog·ical means. 

"Glen Park" Formation.-The "Glen Park" Formation of Illinois was at one time called the "Hamburg Oolite.'! It is not the same age as the type 

Glen Park of Missouri, the former being Mississippian and the latter Devonian, but a new name has 

not yet been introduced. It occurs only in western 

GROUP 

North Hill 

New Albany 

New Albany 

New Albany 

+ 

NORTHWESTERN REGION 

FORMATION 

Starrs Cave Limestone 

Prospect Hill Siltstone 

McCraney Limestone 

Hannibal Shale 

COLUMNAR 

SECTION 

~-----­ '"" -_-_-_ -_ -_-_ J----_-_ ------ 1------------

~-----_-_-:-_-_-_ 

=-= -=-:=:-=-=-

1 1 1 

1 l I 

I I I 

I I I 

I I I 

I I I 

I I I 

I I I 

I I I 

I I I 

I 1 1 

1 1 r 

.,_-_-_-_-_-_:_ --_________ _ ,_-_ -_-_-_-_-_ ,_---_-_-_-_:-

f----_ -_ ---_--: 

.,_-_ -_-_ -_ -_-_ f--_ -_-_-_ -_-:. 

.,_-_-_-_-_-_-_ .,_-_ -_-_-_ --.-

....... ----.::::::--=--::::.. 

------

----

.,__ ---=---= I-- __::::::::.- -

r---

---

.,__-_--

---

1--- -:-----:... 

f----

--

1---- ~---=--

.,__-- -- -----

.,__ ------= 

WESTERN AND CENTRAL REGION 

I I I 

Chouteau Limestone 1 1 l 1 

Hannibal Shale 

I I I 

.,_ ---- ___ _ ----

----=-=. 

.,___ =--

Nutwood Shale ~ --_--:, 

Member '"=-----=--

"Glen Park" 

~-----= 

= J_----=---..J..-

----1. -=_...1...-::.==-

-.J... 

o 1 o 1 o 1o 

olololn 

EASTERN AND SOUTHERN REGION 

Chouteau Limestone l l 

--- ---- 1-----

Hannibal Shale ~-------- .,___ ---=-- 1---- ---=--

THICKNE~,S 

(METERS, 

0-3 

6-7.5 

6-12 

6-30 

0-21 

0-21 

0-12 

0-6 

Q-9 

FIGURE 3.-Columnar section of the Kinderhookian Series 

(Willman and others, 1975). 
EXPLANATION 

-15- Isopach-contour 

interval 7.5 

meters 

_,; Outcrop areas and 

areas truncated 

by Pennsylvanian 

rocks 

E Eroded 

0 20 40 ·MILES 

E-3 E3 I 

0 20 40 KILOMETERS 

H HI 

ILLINOIS 

FIGURE 4.-Thickness of the Kinderhookian Sedes (Willman and others, 1975). 

L5 
L6 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

and ~central IHinois and is exposed in bluffs along ' 

the Miss·issippi and lo·wer Illinois Rivers, where its 

thicknes~s is less than 8 m. It is a highly variable 

unit, and ·conglomerate, sandstone, fine-grained limestone, oolite, siltstone, and shale represent nearshore facies. The contact with the underly~ing Devonian appears to be erosional. 

Hannibal Shale.-The Hannibal Shale is a green 

to gray argillaceous siltstone grading to sHty shale. 

In western Illinois, a siltstone facies about 12 m 

thick was once differentiated as the English River 

Formation, but the name has been dropped. In the 

southern part of the outcrop area, a lens of black 

shale is differentiated as the Nutwood Member. The 

Hannibal thins eastward from a maximum thickness of about 30 m in western Illino·is. In eastern 

Illinois it is very thin or absent and is difficult to 

distinguish from the underlying Devonian Saverton 

Shale. 

Chouteau Limestone.-The Chouteau Limestone is 

J.i.ght brownish to greenish gray and lithographic to 

very fine grained. Locally, it is a fine-grained dolomite, and ·in a narrow belt it is red or pink. It is 

widespread across central and southern Illinois. 

Generally, it :is 3 to 6 m thick, but it thickens to 

nearly 24m locally in western Illinois. Its extensive 

occurrence, contact with overlying and underlying 

shale, and distinctive "kick" on electric logs make 

it an excellent marker bed in subsurface studies. 

Normally, it is conformable on the Hannibal Shale, 

but .in southwestern Illinois locally it overlaps the 

Hannibal and lies unconformably on Devonian to 

Ordovician formations. The name "Rockford," appHed to the formation in Indiana, was used for 

a while in southeastern Illinois, but the older name, 

"Chouteau," is now accepted fo:r all Illinois. 

North Hill Group .. -The North Hill Group includes the McCraney Limestone at the base, the 

Prospect Hill Siltstone, and the Starrs Cave Limestone. It is extensive dn Iowa, but in Illinois it is 

confined to a narrow belt east of the Mississippi 

River. It correlates with the Chouteau Limesfone 

and is conformable on the Hannibal Shale, but it 

~is unconformably overlain by the Burlington Limestone. 

V ALMEYERAN SERIES 

The Valmeyeran Series is the thickest of the three 

Mississippian series (fig. 5). I:t includes rocks ~contemporaneous with the section from the base of the 

Meppen Limestone to the top of the Levias Member 

of the Renault Limestone (fig. 6). The Valm·eyeran, 

especially the lower part, shows important facies 

changes (fig. 7) described later in the section "Environment of Deposition." 

M eppen Limestone Formation. - The Mep.pen 

Limestone is dolomitic limestone, or calcareous dolomite that commonly contains many calcite geodes. It 

occurs in western Illinois from Calhoun County to 

Monroe County and has a maximum thickness of 

about 7 m. It is unconformable on the Chouteau, and 

is conformably ove.rlain by the Fern Glen Formation. It was formerly called Sedalia in Illinois because of litholog.ic similarity to the Sedalia of Missouri, but the ·conodont faunas .show that the Missouri Sedalia is Kinderhookian, whereas the Illinois 

Meppen is Valmeyeran. 

Fern Glen Formation.-The Fern Glen Formation 

consists of red and green calcareous shale and of 

gray, green, and red limestone and dolomite that is 

partly argillaceous. Occurring in southwestern 

Illinois from Randolph County north to Jersey 

County and northeastward to Champaign County, 

the formation generally is less than 15 m thick, but 

in a few small areas it approaches 30 m. It overlaps 

the Mepp·en to rest on rocks as old as the Ordovician 

Maquoketa Shale Group and grades laterally and 

vertically into the Burlington Limestone. 

Burlington Limestone F01·mation.-The Burlington Limestone occupies an irregular triangular area 

in western Illinois from. Henderson County on the 

northwest to Jackson County on the south and 

Iroquois County on the ea~st. Cropping out in the 

Mississippi River bluffs from Quincy to near Alton, 

Ill., the Burlington commonly is 30 to 45 m thick, 

but locally is as much as 60 m. To the southeast, it 

thins abruptly against the Borden Siltstone. In 

northwestern Illinois, the Burlington is very pure, 

coars·ely crY'stalline, light-gray limestone containing 

a few beds of dolomitic limestone. Chert is common, especially in the middle and upper parts of the 

formation. Large crinoid stems are abundant, and 

some beds are almost entirely crinoid debris. 

Farther south, the Burlington becomes more cherty, 

crystalline limestone becomes less abundant, and 

fine-grained beds are more common. In the southern 

part of its ~extent, the Burlington and the overlying 

Keokuk are difficult to discriminate, except by their 

fossils; thus, they are generally referred to as the 

Burlington-K·eokuk Limestone. The Burlington is 

conformable on the Fern Glen and Meppen ·and overlaps them. to lie· unconformably on older strata. 

Keokuk Limestone Formation.-The Keokuk 

Limestone occupies much the same area as the Burlington and is 18 to 24 m thick over most of its extent. It is fossiliferous cherty limestone interbedded 
EXPLANATION 

---300--Isopach--contour interval 

60 meters 

• Outcrop area 

E 

. . 

. . . 

. . . 

0 

Subcrop area (Top eroded 

beneath Pennsylvanian) 

Eroded 

20 40 MILES e--=3r---T--~~~--~--~) 

0,........._2-r-0---.-...;.,40 Kl LOM ETERS H HI 

ILLINOIS 

FIGURE 5.-Thickness of the Valmeyeran Series. Thickness is shown where Chesterian strata are present (Willman and others, 1975). 

L7 
LS THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

with fine-grained limestone, argillaceous dolomite, 

and calcareous gray shale. The Keokuk is generally 

thinner bedded and darker than limestone, of the 

Burlington, and the shale partings are more numerous. Both formations are mainly biocalcarenites. In 

the type region, the lower 9 m of the Keokuk is very 

cherty and is differentiated a's the Montrose Chert 

M~em.ber. 

Borden Siltstone Formation.-The Borden Siltstone is gray to greenish-gray siltstone, glauconitic 

in part, grading to silty shale. The maximum thickness is about 200 m. The siltstone was deposited in 

a delta that enters Illinois in the vicinity of Edgar 

County in east-central Illinoi's and extends almost 

to the southwest border. Lenses of co~arse siltstone 

and very fine s~andstone near the base of the Borden 

are informally called the "Carper sand." A similar 

lens in central Illinois centering on Christian County 

is differentiated as the Bilyeu Member. The Bilyeu 

reaches a thickness of 45 m.; a part extends westward beyond the Borden and into the Warsaw Shale 

as· a member of the Warsaw. To the northwest, the 

Borden is separated from the Warsaw Shale by a 

vertical cutoff at the edge of the Burlington-Keokuk. 

To the south and east, the Borden is separated from 

the equivalent Springville Shale by a vertical cutoff along the line where the siltstone thins to less 

than 30m. 

Springville Shale Form.ation.-The Springville 

Shale is greenish-gray to dark brownish clayey 

shale. Locally, it is mottled red and green and has 

been informally called the "calico shale." The 

Springville is equivalent to the Borden but was deposited in deeper water. Near Jonesboro in Union 

County, the basal part of the Springville is differentiated as the State Pond Member. The member is a 

greenish-gray, soft, glauconitic shale containing 

phosphate nodules and is only about 40 em thick. 

The member is a deepwater equivalent of the Fern 

Glen, Burlington, and Keokuk Limestones. 

Fort Payne Formation.-The Fort Payne Formation is dark, very fine grained, siliceous, cherty limestone. Extending from the Ohio River to southwestern Clark County, the formation occurs only in 

southeastern Illinois and is rarely exposed. Slightly 

more than 180 m thick at the southern end of Pope 

County on the Ohio River, it thins northward and 

westward. The Fort Payne was deposited in a deepwater basin bordered by the foreset slopes of the 

Borden Siltstone delta in southern Illinois and overlies the Springville Shale, the Chouteau Limestone, 

or the lower part of the foreset slope of the Borden 

delta. 

WESTERN ILLINOIS 

FORMATION MEMBER COLUMNAR THICKNESS 

SECTION (METERS I 

I t::. I~ 

St. Louis I t::. I 

Limestone J I 12-54 

It::. I 

/ / Salem 

""" Limestone olo 0 IO D-12 

Sonora ·...,...:...·.·.~·. Q-1B / - I'. - Warsaw .,. Shale ,____,..__..:: 12-30 

- 8 8 

Keokuk £:.1 !::./!::. 18-24 Limestone Montrose Chert t::.t::.t::.lt::.t::.t::. 9 

I t::. /t::. 

!::./!::. It::. 

Burlington t::.l t::. It::. 30-60 Limestone t::. I t::./t::. 

t::.,_l t::. J t::. 

I I 

Fern Glen " I I v D-24 

Meppen " --=cji' R .= £:. ;::::=- v 0-6 Limestone / ®/ 

A 

FIGURE 6.-Columnar section of the Valmeyeran 

Series in Illinois (Willman and others, 1975). 

Ullin Limestone Forrmation.-The Ullin Limestone is mainly a light-colored bryo·zoan and crinoidal limestone. In southern Illinois, its maximum 

thickness is slightly more than 240 m in northern' 

Hamilton County, and it is generally thick in a belt 

running northeast and southeast of that location. 

It thins away from this belt and pinches out to the 

northwest along an irregular line running from 

Jersey County to Champaign County. The Ullin 

overlies the Fort Payne Formation, but where the 

Fort Payne is absent it overlies the Borden, Springvine, Warsaw, or Chouteau Formations. Generally, 

it can be divided into two members, the Ramp Creek 

Limestone Member, which is cherty, argillaceous 

limestone 0 to 150 m thick, and the Harrodsburg 

Limestone Member, which consists of light-colored 

bryozoan and crinoidal debris that is generally 

lighter colored, coarser·grained, less cherty, and les.s 

argilla~ceous than the underlying Ramp Creek. More 

than 240 m thick in Hamilton County, the Harrodsburg thins northward and pinches out at the margin 

of the Ullin. The two members are similar in many 

places, ~and, in about one-third of the extent of the 

Ullin, they cannot be differentiated. The Ullin filled 

deepwater trenches between the foreset slope of the 

Borden delta and the depositional slope of the Fort 

Payne Formation. 

Warsaw Shale Formation.-The Warsaw Shale 

consists of fossiliferous gray shale containing interbedded argillaceous limestone. Quartz geodes are 

common and locally abundant. The Warsaw grades 
FORMATION 

Aux Vases Sandstone 

Ste. Genevieve 

Limestone· 

54m-90m 

St. Louis 

Limestone 

Solem 

Limostone 

105m-120m 

Ullin Limestone 

27m-45m 

Borden 

Silts ton a 

• Thlcknooo In Monroo Countv 

CENTRAL ILLINOIS 

MEMBER 

Rosiclare · 

Sends to no 

COLUMNAR 

SECTION 

Joppa 7 7 

Karnak Limestone .

0 .

1 • ~ • 1. 0 . 

THICKNESS 

(METERS) 

10.5-13.5 

9-18 

6-9 

Sper Mountam J o T o I o 1\ Sandstone o o I o o _l o I \'--__ __, 0-12 

oTooloo Fredonia ··1 J Limestone ] 0 I o 

*Rocher 

*Chalfin 

*Fults 

*Kidd 

Harrodsburg 

Limestone 

Ramp Cr'eek 

Limestone 

Bilyeu 

0-45m 

B 

T I 

7 7 

I £:,. l 

T l 

I I £:,. 

I J 

1 1 

7 / 0 I 0 lo 

T 0 J 0 

0 I 0 J 0 

1 0 1 0 

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• 0 ••• 0. 

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••••••• 0 

....... 

........ 

======-=-= 

========= 

33-48 

54-120 

3-21 

7.5-18 

7.5-10.5 

Q-6.7 

18-30 

9-1!? 

3G-195 

ILLINOIS 

FIGURE 6.-Continued. 

FORMATION 

SOUTHERN ILLINOIS 

MEMBER COLUMNAR 

SECTION 

L9 

THICKNESS 

(METERS) 

1----R....:.e_na_ul_r_u_m_es_to_n_e_+--~Limr.;l~~~~~~;;ne:--...// : · ·. · ·. · ·. · ·. · ·. · ·. · i'\.'-_.0-3 __ -1 

Aux Vases Sandstone s:~~~c~~~~ / .'. · .. ·~ .. ·. ·. . 6-12 

1-----------+--J-op_p_a-~-/ o Ia o I o Ol\ 6-12 

Karnak . 

0 . ~ I? ? ? '----9--12--1 

Ste. Genevieve 

Limestone 

30m-60m 

St. Louis 

Limestone 

Salem 

Limestone 

Ullin 

Limestone 

45m-240m 

Fort 

Payne 

Springville Shale 

Limestone ]/ . Ia . 0 l·o . '\. 

s~;n~s~~~~ain o o I o o Ia 1\.'---_1._5-3_---l 

I . ·/ ·. Fredonia 0 1 0 Ia Limestone ·T 1 

Harrodsburg 

Limestone 

Ramp Creek 

Limestone 

t::. I 6. I 

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I I 

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I I £:,. I I 

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ol o o Ia o 

o ala ojo 

ala OIO·o 

0 0 I 0 0 j_O 

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6.6.16. 6.J6. 

t::.lt::.t::.lt::.t::. 

6. A_l A t::.jA 

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t:.Ait:.ATA 

AIAt:.lt:.A 

A t::.l £:,.A I A 

Alt:.AIAt:. 

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t:.IAAit:.A 

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t::.lt::. t::.Jt::. £:,. 

A AI A A It:. 

t::.l £:,. £:,. I A £:,. 

State Pond B-0.4 \.. ~--==-

c 

36-42 

9B-150 

3B-150 

B-240 

B-150 

B-185 

0-30 
L10 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

WEST 

METERS 

[

60 

30 

0 

EAST 

Borden Siltstone 

Limestone 

Springville Shale 

FIGURE 7.-Diagrammatic east-west cross section across central Illinois showing the Borden Siltstone delta (from Lineback, 1968) . 

eastward into the Borden Siltstone, from which it 

is separated by a vertical cutoff. It is nearly 30 m 

thick in western Illinois, where it crops out in the 

bluffs along the Mississippi and Illinois valleys and 

thickens to about 90 m in east-central Illinois. The 

corkscrew-like axes of Archimedes are very abundant. The Warsaw is overlain by the Sonora Formation or by the Ullin, Salem, or St. Louis 

Limestones. 

Sonora Formation.-The Sonora Formation includes: sandstone, generally light buff, dolomitic, 

argillaceous, and fine grained; shale, generally 

greenish gray and sandy; dolomite, sandy to argillaceous, and sparsely fossiliferous. The lithology 

varies laterally and vertically, and is characteristically sandy. The Sonora is about 0.6 to 6 m thick and 

crops out in the bluffs of the Mississippi and its 

tributaries in Adams and Hancock Counties. Both 

Salem and St. Louis overlie the Sonora, and the 

latter contact varies from conformable to erosional. 

The Sonora grades laterally into· the Salem Limestone and the upper part of the Warsaw Shale. 

Salem Limestone Formation.-The Salem Limestone is mainly crossbedded biocalcarenite composed 

of fossil fragments, endothyrid foraminifers and 

other small fossils, and oolites or oolitic-like overgrowths. Minor components include sucrosic dolomite, dolomitic limestone, chert, sandstone, anhydrite, and gypsum. More than 150 m thick in northern White County, it thins to a line running from 

Jersey to Douglas County with only patches of 

Sal~em northwest of this zero line. The Salem overlaps the Ullin to lie on the Warsaw Shale or Sonora 

Formation. The upper part of the Salem grades 

laterally into the overlying St. Louis Limestone. In 

the outcrop area in western Randolph, Monroe, and 

St. Clair Counties the Salem is divided into four 

members: the Kidd (at the base), the Fults, the 

Chalfin, and the Rocher. 

St. Louis Limestone Formation.-The St. Louis 

Limestone is typically a micritic to lithographic, 

cherty limestone, light to dark gray and brownish 

gray. It also includes beds of dolomite and evaporite 

deposits. One to three beds of gypsum and anhydrite 

occur extensively in the northern part of the· subsurface St. Louis. Limestone breccias in the outcrop 

areas are regarded as indicatjng the former presence of evaporite layers. The St. Louis is about 150 

m thick in southeaste·rn Illinois, but it thins to the 

north and northwest to less than 60 m before being truncated by pre-Pennsylvanian erosion along a 

line running west from Edgar County to Mason and 

Cass Gounhes and then south along the Illinois 

River to Alton. Several large outliers are in the area 

from Fulton to Hancock and Adams Counties. The 

St. Louis is well exposed at Alton and north along 

the Illinois Valley and the Mississippi Valley south 

of St. Louis from St. Clair through Monroe to western Randolph Counties. Another good exposure is 

along the Ohio River in Hardin County in southeastern Illinois. Abundant sinkholes usually characterize the outcrop area of the St. Louis. In general, the St. Louis is darker, more cherty, finer 

grained, and much less oolitic than the overlying 

Ste. Genevieve Limestone. Locally, at the top of the 

formation, strata of St. Louis-type lithology are interbedded and intergrade with strata of Ste. Genevieve-type lithology, so that placement of the forma-
ILLINOIS L11 

tion boundary is somewhat arbitrary. The contact 

is placed below the lowest prominent oolitic bed. 

Ste. Genevieve Limestone Formation.-The Ste. 

Genevieve Limestone is mainly limestone in· massive 

beds, much of which is oolitic and crossbedded. 

Some of the oolite is coarse and notably porous. In 

some oil fields, it is a reservoir rock and is informally called "McClosky lime." The lim,estone is generally light gray or light olive gray, but some oolitic 

rock is nearly white, and some of the lower part of 

the formation is gray or brownish gray. Chert is 

less abundant than in the St. Louis Limestone. Thin 

beds and lenses of sandstone and sandy limestone, 

som·e of which are widely traceable, occur mainly 

in the upper half of the formation. Locally, the limestone at the base of the formation is sandy, and near 

its western border the base is conglomeratic and 

rests unconformably on the eroded top of the St. 

Louis Limestone. The Ste. Genevieve is about 91 m 

thick in southern Illinois and is more than 61 m 

thick in south-central Illinois, thinning to the north 

and west to less than 30 m .. It crops out from near 

Alton and St. Louis south along the Mississippi 

Valley and from Union County eastward across 

southern Illinois to Hardin County. Much of the 

formation is abundantly fossiliferous. The contact 

with the 1overlying Aux Vases Sandstone is conformable, but is marked by a series of downward 

steps to the west as limestone beds in the upper part 

of the Ste. Genevieve grade westward into sandstone of the Aux Vases. The Ste. Genevieve is divided into four members. 

The Fredonia Limestone Member is mainly light 

gray, oolitic, crossbeddeti, and crinoidal limestone, 

but it includes some darker, lithographic limestone 

beds like those in the St. Louis. The Fredonia is generally 24 to 30 m thick, but north of Effiingham 

County it thins rapidly to 6 m or less. The Spar 

Mountain Sandstone Member consists of sandstone 

and siltstone that grade to sandy or silty limestone. 

Locally, in the northern part of its extent, the sandstone is coarser than elsewhere and the sand grains 

are better rounded. The member extends throughout 

most of the area of the Ste. Genevieve. Its thickness is erratic, ranging from about 3 to 12 m, and 

the greater thicknesses are generally in the north. 

In the western part of the basin, where the overlying Karnak Member thins out, the Spar Mountain 

grades laterally into the Aux Vases Sandstone and 

is separated from it by a vertical cutoff. The Karnak 

Limestone Member is a persistent unit about 3 to 

11 m thick, except that in western Washington 

County it wedges out into the Aux Vases Sandstone. 

The Joppa Member has a varied lithology, including beds of limestone, dolomite, sandstone, and 

shale, in part red and hematitic. It is 6 to 15 m 

thick. The Joppa is recognized in southeastern 

Illinois where limestone beds are present in the 

interval, but to the north and west the limestone 

beds thin out into sandstone regarded as Aux Vases. 

Aux Vases Sandstone Formation.-The Aux 

Vases Sandstone consists of sandstone·, siltstone, 

minor amounts of shale, and, locally, a little dolomite and limestone. The •sandstone is light gray to 

greenish gray, calcareous, and grades to coars,e siltstone. Locally, it is pink or red and hematitic. In 

southern Illinois, where the Joppa Member is recognized, the Aux Vases is commonly 6 to 12 m thick. 

To the north and west of this ar·ea, the Aux Vases 

includes Joppa equivalents and is correspondingly 

thicker, being about 18 to 24 m. In a small area 

where the Karnak is absent, the Aux Vases includes Spar Mountain equivalents and is 40 to 49 m 

thick. The thickness map of the Aux Vases shows 

discontinuities that reflect the areas where the base 

of the Aux Vases is stepped down. The, Rosiclare 

Sandstone Member is the main body of the Aux 

Vases in southeastern Illinois where it overlies the 

Joppa Member of the Ste. Genevieve. 

Renault Limestone Formation.-The Renault 

Lim~estone is a relatively thin but extensive formation. It averages about 2.5 m thick, thickening 

s·outhward to 6 to 9 m and reaching slightly more 

than 12 m in Johnson County. The Renault consists 

of two members: the Levias Limestone Member, a 

relatively pure limestone, Valmeyera.n in age; and 

the Shetlerville Limestone M,ember, a more or less 

sandy lim.estone, Chesterian in age. The Levias is a 

medium- to coarse-grained, white, oolitic limestone, 

containing some pink and light green ooliths. The 

basal 1 or 2 m are sandy. It is best developed in 

Hardin County in southeastern Illinois, where it 

commonly is 3 to 8 m. thick, but it is less easily 

distinguished outside Hardin County and is recognized only sporadically north of Lawrence County 

and west of Franklin County. It contains Platycrinites penicillus, a fossil crinoid marking the 

uppermost part of the Valmeyeran Series. The 

Shetlerville Member is mostly brownish-gray or 

dark-gray limestone, partly ·oolitic, and somewhat 

sandy. The basal contact is sharp and may be unconformable. The member is about 5 to 6 m thick in 

the vicinity of Hardin County, and it makes up 

most, or all, of the Renault outside that area. The 

crinoid Tala'rocrinus is present, and marks the lower 

part o.f the ·cheste·rian Series. The Popcorn Sand-
L12 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

stone Bed in the base of the Shetlerville is dominantly sandstone. It has some shale and impure 

limestone and is about a ·meter thick. It occurs 

locally in Hardin County but is rarely found in 

Illinois outside that area. 

CHESTERIAN SERlE'S 

The Chesterian Series occupies the Illinois basin 

(fig. 8) from De Witt County on the north to the 

northern part of Johnson County on the south, and 

from Indiana on the east to within a few miles of 

the Mississippi River on the· west. The series 

thickens southward to about 450 m in northern 

Johnson County. Nearly all the formations thicken 

southward to their truncated edges. The series is 

beveled by the sub-Pennsylvanian erosion surface. 

The outcrop belt extends along the Mississippi Valley from near Alton in western Madison County, 

southward to Union County, and thence ·eastward 

to Hardin County and the Ohio River. To the north 

and east of the vicinity of Alton, the margin of the 

Chesterian is overlapped by the Pennsylvanian System. The Chesterian includes 19 named formations 

plus the Shetlerville Member of the Renault Formation at the base (fig. 9). The Aux Vases Sandstone, long considered the basal formation of the 

Chesterian, is excluded, because it is below the top 

of the Valmeyeran Platycrinites penicillus Zone. 

Yankeetown Sandstone Formation.-The Yankeetown Sandstone is chert and cherty sandstone at the 

type section, but in the subsurface in western Illinois it is a sandstone and shale unit. To the northeast, in Washington County, it becomes a thick sandstone, and to the southeast it changes to a limestone 

·and shale unit. Although only about 6 m thick in the 

outcrop area, the Yankeetown thickens to about 30 

m in southwestern Illinois but is only about 18 m 

thick over much of its extent. 

Paint Creek Group.-The Paint Creek Group consists of the Downeys Bluff, Bethel, and Ridenhower 

Formations. The name is used in western Illinois 

where the Bethel, normally a sandstone, is a shale. 

Downeys Bluff Limestone Formation.-The 

Downeys Bluff Lim~estone is white to light-brownish 

gray and crinoidal. Pink chert replaces many of the 

crinoid segments, especially in western Illinois. In 

southernmost Illinois, the Downeys Bluff consists 

of two benches s·eparated by a thin shale, and g·enerally is 6 to 9 m thick. The upper bench is typically cherty and the lower is slightly silty or very 

finely sandy. Farther north, the Downeys Bluff consists of only the upper of the two benches, generally 

is 2 to 3 m. thick, but locally is 3 to 6 m thick. 

West Baden Group.-The West Baden Group consists of the Bethel, Ridenhower, and Cypress Formations. The name is used in part of southeastern 

Illinois, where the Ridenhower is dominantly sandstone and difficult to separate from the sandstone 

formations above and below . 

. Bethel Sandstone Formation.-The Bethel Sandstone generally is 6 to 12 m thick in the northern 

and western part of its extent and thickens southeastward to about 30 m in northeastern Gallatin 

County. Dominantly sandstone, the Bethel grades to 

shale in western Illinois. The sandstone generally 

is slightly coarser grained than the other Chesterian 

sandstones. Locally, it includes a few small quartz 

pebbles and a basal conglomerate of limestone and 

shale pebbles. A prominent 5-m bed of red clay 

occurs along the outcrop belt in southwestern 

Illinois. 

Ridenhower Formation.-The Ridenhower Formation is mainly shale, but also includes beds of 

limestone and sandstone that locally are thick. The 

limestone is diversified and has sandy, oolitic, crinoidal, and lithographic varieties. The proportion of 

limestone in the formation is greatest in western 

Illinois, and the proportion of sandstone is greatest 

in southeastern Illinois. The formation generally is 

6 to 12 m thick, but at several places it is more· than 

24 m. In some parts of central and eastern Illinois, 

the formation divides into three members-the 

Beaver Bend Limestone (below), the Sample Sandstone, and the Reelsville Limestone-but in most of 

Illinois, these members cannot be recognized. 

Cypress Sandstone Fm·mation.- The Cypress 

Sandstone in western Illinois is generally less than 

24 m thick, but in eastern Illinois it is more than 

37 m thick and locally more than 61 m thick. 

Typically, the lower half to three-fourths of the 

formation consists of one or two bodies of massive 

sandstone. The upper part of the Cypress is more 

shaly than the lower; typically it is shale interbedded with thin to moderately thick sandstone and 

siltstone lenses. A fairly extensive red shale occurs 

about 3 m below the top of the Cypress. A thin coal 

occurs near the top of the Cypress in extreme 

southern Illinois. In northern and western Illinois, 

where the Cypress is relatively thin, the formation 

is nearly all shale, and has a high proportion of red 

and green shale. 

Golconda Group.-The Golconda Group is a limestone-shale unit, ·consisting of the Beech Creek 

Limestone (below), the Fra:ileys Shale, and the 

Haney Limestone. A sandstone member is locally 

present in the Fraileys Shale. 
ILLINOIS 

EXPLANATION 

-240- Isopach-contour~ ~~~..,..:::yL-..._~__;~--1---t::Jcf:::;=~"\\ 

0 20 

lnterval30 

meters 

0 20 40 KILOMETERS 

E3 E3 I 

FIGURE B.-Thickness of the Chesterian Series (Willman and others, 1975). 

Ll3 
L14 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

en 

w 

a: 

w 

en 

z 

<(. 

~ 

w 

len 

w 

X 

u 

w 

0 

<( 

+-

en 

COLUMNAR 

SECTION 

b. lA lb. I' 

MEMBER FORMATION 

GROVE CHURCH 

Goreville 

Cave Hill KINKAID· 

Negli Creek 

~ ~ ... f==J"'·Q~'-,:.1.,:;):1--T---F-o_~-:-:-:-tio_·n __ -1 

DEGONIA 

CLORE 

~ 

> .....J 

w •· .. : ::·:: · • • PALESTINE 

P:)~::· ~-;;':.·a-~ ....... ·..+. ·--:-------+-------.., 

..... 

:.·· 

.·.·.:· . . : .·.: : 

( 

Allard 

Scottsburg 

Walche 

MENARD 

r 

WA~ TERSBURG 

VIENNA 

TAR SPRINGS 

GLEN DEAN 

·HANEY 

. ··.·.:···· .. I ~g>:, .. /,: 

::E 

HARDINSBURG 

~ ~ <:0? ·'-r---------------~ FRAILEYS 

~ ({::·:j~~:::=.<f~):===B=ig=C=Ii=fty==;::;:f---::==-:--=:=--1 ~ BEECH CREEK 

GROUP <( ~ 

W. E. ::Eo ~~ 

~ 0 

-

(3 

z 

0 

u 

...J 

0 

(!) 

w 

0.. 

0 

0.. 

CYPRESS 

~ .,.5~{·\:\\.~.;..:1~ ---R-e-el-sv-i-lle---1---------+---~ ~<(* ~ ~ <::: 

·~c~~··~.::~~~~-~~:J~~~S~a~m~p~le~==:+---R-ID_~_N_H_o_w_E_R~ Beaver Bend 

0 .·.:·:· .. ·.··' BETHEL 

~~~~~~ .. ~·~::~~:~·~·r·~~h-~-----------~-------------~ "'-l A ..l:::""' "\. DOWNEYS BLUFF 

~\\:)3\ YANKEETOWN 

1---4----1. . . . . . . . 'tl Shelterville 

Levi as 

Rosiclare 

RENAULT 

z 

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AUX VASES 

STE. GENEVIEVE 

Fredonia 

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um 

t 

BIO-ZONES 

1----

FIGURE 9.-Columnar section of the Chesterian Series (from Swann, 1963) showing biozones 

(from Collinson and others, 1971). In the columnar section, the blank areas are shale. 
ILLINOIS L15 

0/caw Gr·oup.-The Okaw Group consists of five 

formations from the Beech Creek through the Glen 

Dean Limestone. The Okaw is used only in western 

Illinois in an area having small limestone outcrops 

that are Haney or Glen Dean but that are difficult 

to differentiate. 

Beech CTeek Limestone Fo'tmation.-The Beech 

Creek Limes.tone ·is a relatively thin but persistent 

unit, commonly called the "Barlow lime." The lower 

part is argillaceous, dark brownish gray, dense to 

subHthographic limestone. The upper part is Hght 

brownish gray, fossiliferous, and ooHtic in part. 

The Beech Greek thickens northward in contrast 

w·ith the other Chesterian formations, which thicken 

southward. I.t is as much as 12 m thick in the north, 

but in Hardin County, •in the south, it is shaly and 

locally absent or too thin to identify. 

F1··aile11s Shale FoTmation.-The Fraileys Shale is 

as much as 30 m thick in Williamson County and 

thins northward to about 9 or 12 m thick before 

being beveled by the sub-Pennsylvanian eros·ion surface. It is dominantly shale, has sporadic limestone 

beds and, locally, a sandstone member. Most of the 

shale is dark gray; however, in the ·southern part of 1 

the Illinois basin, a persistent red shale occurs 1 

or 2 m below the top of the Fraileys. Much of the 

limestone consists of lenses of fossil detritus, in 

part containing abundant red, orange, or green 

fossil fragments. The Big Clifty Sandstone Member 

enters Illinois from the east and thins out westward 

within a few tens of kilometers. The membe.r is 

usually about 5 to 6 m thick and occurs near the 

middle of the Fraileys, or less commonly near the 

base. 

Haney Limestone Formation.-Haney Limestone 

is about 30 m thick in southern Illinois and thins 

northward to less than 5 m. It is mainly limestone 

and some interbedded shale. The limestone is coarse 

grained, fossiliferous, and much of it is oolitic. In 

Randolph County, a 6-m bed of white oolite is informally named the "Marigold Oolite." To the northwest the Haney grades to a shale that is difficult to 

differentiate from the Fraileys or the Hardinsburg. 

H a1·dins bu1·g Sandstone F oTmation.-Hardinsburg Sandstone has a thick-bedded sandstone facies 

and a thin-bedded shale and shaly sandstone facies. 

Much of the sandstone is light gray and very fine 

grained. In the thick bodies, the sandstone may be 

white and fine grained; in the thin bodies it may be 

gray or green and finer grained, in places grading 

to siltstone. About 10 m o.f red, green, and dark 

gray shale containing thin beds and nodules of red 

and brown, lithographic limestone and dolomite lie 

at the base of the Hardinsburg. Locally, this shale 

is cut out by an erosional surface that commonly 

separates it from the overlying sandstone facies so 

that sandstone rests directly on the Haney Limestone. In southeastern IUino•is, the Hardinsburg is 

18 to 25 m thick; to· the northwest it thins to about 

6 to 12m. 

Glen Dean Limestone FoTmation.-Shale separates 

the Glen Dean Limestone in the south into upper 

and lower limestone units. In the north only the 

lower unit generally persists, and the formation is 

correspondingly thinner. The limestone is coarse 

grained and fossiliferous; parts are oolitk, and 

some strata are cherty. In the south, the Glen Dean 

is 20 to 25 m thkk. In the north, where only the 

lower limestone unit ois present, the formation thins 

to only 2 to 6 m. 

TaT SpTings Sandstone FoTmation.-The Tar 

Springs Sandstone is nearly all sandstone, white to 

light gray, very fine to fine grained, and mostly 

friable but containing some well-cemented layers. 

Also present are: shale, dark gray and slightly carbonaceous; sHts.tone, mediurri to dark olive gray; and 

shaly sandstone, light to dark olive gray. Near the 

southern border of the Tar Springs, thin beds of 

coal occur locally near the top and middle of the 

formation. The thickness of the Tar Springs generally ranges from 23 to 40 m in thickness, but the 

maximum 'is more than 45 m. Near its northwestern 

border it thins to about 15 m. 

Vienna Limestone FoTmation.-The Vienna Limestone is a thin limestone, mainly dark brownish gray 

and very fossiliferous. Much chocolate-brown chert 

is present in the outcrop, but chert is rare in the 

subsurface. The maximum thickness of the Vienna 

is about 9 m near its southern edge. About 48 km 

to the north, it thins to about 3 m; over most of 

its extent, it is ahout 1 m thick. 

WalteTsbu?·g Formation.-The Waltersburg Formation is mainly dark gray, slightly carbonaceous 

shale, 'in part silty and sandy. A thin seam of coal 

is present locally near the top of the formation 

close to it~s southern border. Sandstone strata in the 

outcrop are characteristically well jointed. The 

Waltersburg generally is 15 to 23m thick, but at the 

west it thins to less than 12 m and thickens to 36 

m :in a small area in Wayne County. 

Menard Limestone Formation.-The Menard 

Limestone generally is 30 to 45 m thick in the southern, 24 to 30 m in the central, and 14 to 18m in the 

northern and northwestern parts of its extent. The 

limestone is argillaceous, dark brownish gray to 

brown and buff, fine grained to lithographic, oolitic 
L16 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

in part, and cherty in part. Fine-to-coarse dark 

rounded grains .give many beds a characteristic 

.speckled appearance. The shale is calcareous, dark 

gray, and fossiliferous. 

The Menard :is .readily divided into .three limestone members. The Walche at .the base 1is 1 to 3 m 

thick and occurs only in the southern part of the 

basin. The Scottsburg overlaps the Walche to the 

north, is 9 to 12 m thick in the south, and thins 

northward to about 2 m. The Allard thins from 

about 9 m in the south to 3 m in the north. The 

shale strata separating these members, and overlying the Allard, are not named units. The shale 

above the Allard is about 6 to 9 m thick in the south 

and 3 to 6 m in the no·rth. Locally, especially in 

the north, the sub-Palestine erosion surface cuts 

into this shale and in places entirely through it. 

Palestine Sandstone Formation.-The Palestine 

Sandstone includes sandstone, shale, and siltstone. 

Much of the sandstone is gray, very fine grained, 

and more or less shaly. The sandstone in the thicker 

bodies is Hght gray to white and coarser grained. 

The shale is dark gray and generally silty to sandy. 

Much of this rock .is slightly carbonaceous. In western Illinois, a thin .coal is at the top of the Palestine at several localities. The Palestine tends to 

thicken slightly southward. Commonly it is 15 to 

18 m thick, and it is thickest where massive, channel-,phase sandstone bodies are present. 

Clore Formation.-The Clore Formation is mainly 

shale throughout most of its extent, but the proportion of limestone increases southward. About 12 

to 18 m thick near its northern and northwestern 

borders, it thickens southward to about 36 m in 

northern Johnson County. In many places the Clore 

is thinned by sub-Degonia channels; in some areas 

sub-Pennsylvanian channels cut into, or through, 

the Clore. 

The Clore includes three members. The Cora 

Limestone Member (below), which consists of interbedded limestone and shale containing locally, 

sandstone lenses, -is about 4 to 13 m thick. The Tygett Sandstone Member, which -is sandstone containing minor amounts of shale, is 6 to 9 m thick 

over much of its extent. The Ford Station Limestone 

Member, which is limestone interbedded with shale 

and rare lenses of sandstone, is 6 to 15 m thi·ck. 

Degonia Sandstone Formation.-The Degonia 

Sandstone typically includes two beds of massive 

sandstone. The upper overlaps the lower, and locally 

both are absent. The shale in the Degonia is gray to 

dark gray, but red at the top of the formation. Thin 

seams of coal occur locally' near the .top and middle 

of the Degonia in southwestern Illinois. The thickness of the formation ranges from 45 min western 

Illinois to as little as 6 m in the southeast. SubPennsylvanian channels cut the Degonia into two 

large and many small areas. 

Kinkaid Limestone Formation.-The Kinkaid 

Limes·tone is about 30 m thick in the north, thickening southward to about 51 m near its southern 

edge. Pre-Pennsylvanian erosion has cut the Kinkaid into many isolated areas. The thick upper and 

lower limestone members apparently were highly 

res·istant to erosion because they cap the Chesterian 

over faJirly large areas. Many slump blocks of the 

limestone are known to occur in the subsurface on 

the slopes of steep-walled sub-Pennsylvanian 

valleys. 

The Kinkaid is divided into three members. The 

Negli Creek Limestone Member (at the base) is a 

massive limestone, cherty, brownish gray, containing scattered coarse fossil grains. The member is 

11 m thick in Franklin County in the south and 5 m 

thick in Effingham County in the north. The Cave 

Hill Shale Member is a limestone and shale unit in 

which the· proportion of limestone increases southward. The basal part is shale, dark gray, and locally 

black. The lower third of the member contains some 

silty shale, a little siltstone, and locally shaly sandstone. The middle part of the member contains a 

variety of carbonate rocks interbedded with a little 

shale. The upper part consists of calcareous dark 

gray and greenish gray shale above and red and 

green shale below. The Goreville Limestone Member is massive and resistant to erosion like the 

N egli Greek, but -it is less extensive and is more 

dissected by pre-Pennsylvanian erosion. Average 

thickness of the Goreville is about 9 m, and thickness ranges from about 8 m in the north to nearly 

15 m in the south. 

Grove Church Shale Formation.-The Grove 

Church Shale, the uppermost formation in the Chesterian Series in Illinois, occurs only in patches in 

southern Illinois in Johnson, Pope, and SaHne Co:unties. An unknown, but probably large, part was 

eroded before the Pennsylvanian was deposited in 

the area. The Grove Church is a gray, fossiliferous 

shale containing interbedded fossiliferous limestone. 

The maximum thickness known is about 20 m in 

northern Johnson County. 

PALEONTOLOGY 

The Mississippian System is named for exposures 

along the western margin of Illinois, and its fossils 

in this State have been intensively studied. The 
ILLINOIS L17 

shale of the Kinderhook~ian Series is relatively unfoss:iliferous, except for spores and conodonts, but 

the Chouteau Limestone ( =Rockford of Indiana) 

at the to~p of the series is famous for its cephalopod 

fauna; part of .this fauna is earliest Valmeyeran in 

age. Fossils are abundant and varied in most of the 

lrimestone and calcareous shale of the Valmeyeran 

and Chesterian Series. Brachiopods are numerous, 

and some formations consist mainly of crino,idal 

debris. Fenestrate bryozoan debris is a•bundant in 

some beds. Archimedes with ,its corks·crewHke axes 

-is so common in some strata that the term "Archimedes limestone" was applied to several stratigraphic uhits in some early reports. Composita 

trinuclea is the commonest M1ississi.ppian brachiopod 

of southern IHinois. Endothyrids are abundant in 

the Salem Limestone. The coral assemblage zone 

Lithostrotionella castelnaui ( = 11Lithostrotion canadensis") and L. p-rolifeTttm is generally equivalent to 

the St. Louis Limestone. Conodonts are common to 

abundant and provide a basis for biostratigraphic 

zonation. More than 20 charact~ristk conodont 

faunas have been recognized in North Ameflican 

Mississippian rocks. In the Chesterian, plant megafossils are found in parts of the sandstones, and 

spores have been described from the thin coals and 

carbonaceous layers. 

ENVIRONMENT OF DEPOSITION 

The Kinderhookian Series thickens westward, and 

the stiltstone component is thickest in western Illinois, suggesting that the main source of sediment 

was wes.t of Illinois. At the base of the series, a 

local eros.ional unconfo·rmity that has about half a 

meter of rel,ief on the top of the· Devonian suggests 

a relatively sho·rt interval of emergence. Oolitic I~imestone of the "Glen Park" at the base of the series 

in central Illinois and oolitic limestone of the thin 

Starrs Cave at the top of the series in extreme 

western Illinois indicate shallow water at these 

times and places. The water may have been deeper 

to the south and east where the series is thinner. 

Here the amount of sedi,ment going into the basin 

may have lead to the "starved" condition that developed later. The close of the K-inderhookian is 

marked by a minor eros•ional unconform.ity at the 

base of the Budington Limestone in northwestern 

Illinois. 

Ea.rly in Valmeyeran time, as the Illinois basin 

sank, important facies ·differences developed in the 

sediments (fig. 7) . In western and northern Illino·is 

where the water was shallow, fossiliferous limestone 

(Burlington-Keokuk) was deposited that built up a 

thick carbonate bank. To the south and east, mud 

was slowly depo;;ited in the deepening basin 

(Springville Sha'le and basal Borden). A siltstone 

delta (Borden Siltstone) encroached from the northeast into this sediment-starved bas,in where water 

depths are estimated to have been from 183 to 305 

m (Lineback, 1968). The deep ... water basin, marginal to the delta on the southeast and south, was 

filled by the cherty, very siliceous Fort Payne Fo·rmation and the bryozoan-rich Ullin Limestone. 

After the delta had ,built up to about the level of 

the top of the Burlington-Keokuk bank, mud and silt 

swept westward across the surface of the Keokuk to 

be deposited in western Illinois as the Warsaw 

Shale. 

Carbonate deposit.ion prevailed during the rest of 

Valmeyeran time. The water was generally shallower than before, the shoreline was to the north, 

and water was deeper to. the south. At times, the 

environment approached the sabkha-type, and evaporites and oolites were deposited. This was a time 

of extensive deposition of thi.ck limestone formations. 

Of the several types of rock composing the Salem, 

the most abundant and characteristic are fine- to 

ooarse~gra•ined calcarenite and fossil-fragmental 

limestone. CoHed Fo·raminifera, such as Globoendothyra, and other small fossils are abundant. Oolites 

and oolitic overgrowths are locally common. The 

former presence of local evapor,ite deposits is suggested by the brecciation of the overlying St. Louis 

Limestone. Beds of extra fine grained dolomite in 

the Salem also suggest a shallow-water environment. 

The St. Louis Limestone also was depos,ited in 

shallow water. Typically, the limestone is very fine 

gra;ined to lithographic and is locally brecciated; the 

dolomite is extra fine grained. Oolitic rock is much 

less common, and the carbonate is generally darker 

and more cherty :in the St. Louis than in the underlying Salem or overlying Ste. Genevieve Limestone. 

Disseminated anhydrite and some fairly thick beds 

of gypsum and anhydrite occur. The transition from 

gypsum to anhydrite is related to depths of burial; 

below 450 m the evaporite is princ-ipally anhydrite. 

The Ste. Genevieve Limestone was depos~ited in a 

shallow-water environment that favored the deposition of oolitic limestone in lenticular or barlike 

bodies at several levels. A few thin strata of sandy 

limestone, sandy ·calcarenite, or sandstone are fairly 

wide,ly traceable, foreshadowing the alternation of 

sandstone and limestone characteristic o.f the Cnesterian. 
LIS THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

The Aux Vas·es Sandstone shows a facies relation 

with the upper part of the Ste. Genevieve Limestone 

in southwestern Illinois. Limestone strata in the 

upper part of the Ste. Genevieve thin and grade into 

sandstone in this area, so that the base of the Aux 

Vases is stepped down to ,include the thicker sand. 

The sand in the A ux Vases probably came from the 

north or northeast rather than from the Ozark area 

itself. 

The Levias Limestone Member in southeastern 

Illinois was deposited in clear, shallow water. Except for the basal few centimeters that are sandy, 

the limestone is a relatively pure, coarse-grained 

ooUte. The break with the overlying Chesterian is 

minor and is marked by an erosional surface of very 

slight relief and sandy beds at the base· of the 

Shetlerville Member. 

The Chesterian Series is characterized by an alternation of sand-shale formations and limestoneshale formations in an irregularly ,cyclical succession. This cyclicity is explained as resulting from 

the shifts of an east-southeast to west-northwest 

trending shoreline (fig. 10). When the sea transgressed northward, limestone was ,laid down in the 

IHinois ·basin; when the sea retreated, sand was 

deposited. The location of major sand bodies is a 

consequence of lateral shifts in the position of the 

distrihutaries of the river that carried sediment into 

the basin from the north. This river has been named 

the Michigan River (Swann, 1963); it may have 

brought sediment from northeastern Canada, but 

the location of the source is not definitely kno-wn. 

This picture of the paleogeography during Chesterian time developed from a study of features in 

the sandstone that indicate the direction of paleocurrents. Detailed mapping of the thickness of sandstone in several of the Chesterian formations has 

shown the position of the distributaries of the 

Michigan R~iver (Potter, 1963). Changes in the rate 

of ~sediment supply have been attributed (Sw~ann, 

1964) to climatic control rather than tectonic ,control, and sediment yield has been controlled mainly 

by rainfall in the source area. Shoreline position 

was dependent on the shifting balance between the 

rate of sedimentation and the rate of sinking of 

the basin. 

In general, the Chesterian formations, except for 

the Beech Creek Limestone, thicken southward to 

their truncated edges in southern Illinois; the proportion and thickness of the limestone in the limestone-shale for~mations also increase southward. The 

Hm.es.tone strata in the lower part of the Chesterian 

(~Glen Dean and older) are generaHy lighter colored 

'\ SHALE \ l \ -.r-, ( ... ;· / ~cu-9-9~ ~ .... ~ I ~~ , t-t~. ,,..~· ,r' f 

v&-"-.;; IQ ) ,.S, ) o ,) ~ LIMEsToNE , INDIANA / r ""'- ~~~ ~_<'-·J'.-,...v '- CINCINNATI 

....,\, ( KENTUCKY S~OAL 

OZARK )1 • .-· 

SHOAL ~·' ( 

.... "" \ -·~I / , '\f\.( ,..) 

150 KILOMETERS \ 

\. 

FIGURE 10.-Paleogeography at an intermediate stage during 

Chesterian sedimentation (from Swann, 1963). 

and purer than the limestone :in the uprper part 

(Vienna and younger), and the amount of oolitic 

rock is much greater in the older formations. A coal 

swamp environment developed several times during 

the Chesterian. Thin coals occur in Jackson and 

Hardin Counties at the top of the Palestine Sandstone; in Johnson, Pope, and Hardin Counties at the 

top of the Waltersburg Sandstone; and in the southern part of the Illinois basin, at ,the top and near 

the middle of the Tar Springs and Cypress Sandstones. 

TECTONIC DEVELOPMENT 

The major tectonic event in Illinois during the 

Mississippian Period was the sinking of the Illinois 

basin which was greatest in southermost Illinois. 

During thi:s period (and until the post-Pennsylvanian development of the Pas.cola arch) the Illinois 

basin was open to the south, and the maximum 

sinking during this time 'is southwest of the, deepest 

part of the present basin. 

At the dose of the Devonian Period, the tectonic 

break was very minor, and local emergence was 

indicated by an erosional surface on the top of the 
ILLINOIS L19 

Louisiana Limestone (uppermost Devonian). A 1 

slight break between Kinderhookian and Valmeyeran Series is recorded along the western edge of the 

Illinois basin, where the Meppen Limestone (basal 

Valmeyeran) rests unconformably on the Chouteau 

Limestone (Kinderhookian). Absence of the Chouteau north of a line running from Cwlhoun County 

to the northeast may be a result of a slight upwa·rping of the Sangam·on arch (fig. 11) at the 

close of the Kinderhookian, accompanied by truncation of the Chouteau. Slight doming of the Ozark 

reg.ion at this time was followed by overlap of the 

Valmeyeran onto rocks as old as Ordovician. 

During the earlier part of Valmeyeran time in 

western Illinois, where the· sea was shallower than 

it was farther south and east, buildup of the Burlington-Keokuk carbonate bank kept in balance with 

the sinking basin. Sinking outpaced sedimentation 

in eastern and southern Illinois, and that part of the 

basin became sediment-starved until the Borden 

Siltstone Delta was built out into the basin from the 

northeast. Near the close of the Valmeyeran, slight 

warping of the Ozark region is su.gg·ested by local 

erosion surfaces and by overlaps near the top and 

base of the Ste. Genevieve Limestone at the southwest edge of the Illinois basin. 

The base of the Chesterian is marked by local 

erosion surfaces and by sandy beds. The base of the 

Cypress Sandstone tends more nearly to parallel the 

bedding of older units than it does the overlying 

Beech Creek Limestone, suggesting slight warping 

of parts of the ba.sin during Cypress tim·e. This, 

and similar, very minor nonparallelism of older and 

younger strata in the Chesterian, may be attributable to the differential compaction and draping of 

younger beds over thick sandstones. Howev·er, an 

abrupt thinning from west to east of the interval 

between the Downeys Bluff and the Beech Creek 

Limestones in the southern part of Crawford 

County in southeastern Illinois is more probably a 

result of local upwarping than of differential compaction. This monoclinal feature may be an early indication of the La Salle anticlinal belt. Other than 

this monocline, thickness maps of individual Chesterian and older Mississippian formations show no 

indication of contemporaneous development of the 

La Salle anticlinal belt. This major structural feature of Illinois mainly began during the interval of 

erosion that followed Chesterian deposition in the 

area. 

ECONOMIC PRODUCTS 

Oil.-As of December 31, 1976, the estimated original oil-in-place in Illinois was 8,968,692,000 barrels 

(1,220 million metric tons) ; the estimated ultimate 

recovery was 3,205,329,000 barrels ( 437 million 

metric tons) . Of this Illinois oil, all Paleozoic, 

6,766,392,000 barrels (922 million metric tons), or 

75.4 percent of the original oil-in-place, and 2,582,-

443,000 barrels (352 million metric tons), or 80.6 

percent of the estimated ultimate recovery, is from 

reservoirs in Mississip.pian strata. 

A little more than 60 percent of the cumulative 

production of Mississippian oil is from sandstones 

in the Chesterian Series, and nearly half this p·roduction is contributed by the Cypress Sandstone. 

Of the other Chesterian sandstones, the Yankeetown 

("Benoist"), Bethel, Tar Springs, and Waltersburg 

are the most important contributors. A little l·ess 

than 40 percent of the cumulative p·roduction is 

from the Valmeyeran Series, and almost all this is 

from ne·ar the top of the series. Of this oil from the 

Valmeyeran, the Aux Vases Sandstone contributes 

about one-third, and the Ste. Genevieve Limestone 

about three-fifths. The most important res.ervoirs 

are in lenses of coarse oolitic limestone (McClosky 

lime) at several levels in the Fredonia Member of 

the Ste. Genevieve. Relatively small amounts of oil 

com·e from the Spar Mountain Sandstone Member 

of the Ste. Genevieve and from the Salem and Ullin 

Lim·estones. 

Gas.-Production of natural gas in lllinois in 

1976 was 1,556 million cubic feet ( 44 million cubic 

meters) , of which only about one-sixth was from the 

Mississippian. Almost all th~ Mississippian gas production was from Chesterian sandstones. Eight of 

39 active underground natural gas storage projects 

in· Illinois use reservoirs in Mississippian rocks, 

but none of thes·e 8 are among the relatively large 

projects in Illinois. 

Fluorspar.-Illinois leads the other States in the 

production of fluorspar. In 1976, production was 

129,000 metric tons. All the ore mined came from 

Hardin and Pope Counties in southern Illinois. The 

ore occurs in fissure v·eins and bedded replacement 

deposits in strata near the base of the Chesterian 

and near the top of the Valmeyeran Series. 

Lead, zinc, and silver.-The fluorspar ore mined 

in Hardin and Pope Counties is treated to recover 

zinc, lead, and silver. In 1974, 3,720 metric tons of 

zinc, 44 7 metric tons of lead, and a small amount of 

silver were recovered. 

Stone.-Stone production in Illinois in 1976 was 

55,100,000 metric tons. Of this .total, almost all 
L20 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

EXPL.ANA TION 

Fault 

+Anticline 

+Syncline 

-+- Monocline 

OE=::::3:=:::2:E0=::3:::=:J40. MILES 

0 20 40 KILOMETERS F3 f+li I 

Herscher 

Dome 

FIGURE 11.-Major tectonic features of Illinois. The Sangamon arch was a Paleozoic 

structure obscured by later structural movement. 
ILLINOIS L21 

crushed and broken limestone and dolomite, about 

one-sixth is from the Mississippian, and most of 

this is from the Valmeyeran. The middle part of 

the Mississippian System-from the top of the New 

Albany Shale Group, or the Borden Siltstone where 

present, up to the lowest sandstone or shale of 

Chesterian or late Valmeyeran age-is sometimes 

called the "Mississippi lime," or, more formally, the 

"Mam.moth Cave Lim·estone Megagroup." This 

mega.group is an important source of limestone in 

Illinois, where it crops out along the western and 

southern borders of the State. 

THE PENNSYLVANIAN SYSTEM 

INTRODUCTION 

The name "Pennsylvanian" was used in 1906 in 

the first report of the pres.ent Illinois State Geological Survey. The terms "Coal Measures" and 

"Upper Carboniferous," which were used before 

1906, were gradually abandoned in later reports 

(fig. 12) The Pennsylvanian was classified as a 

series until it was recognized as a system in about 

Worthen S. Weller DeWolf Shaw and Savage Wanless 

1875 1906 1910 1912 1929, 193.la 

Formations 

subdivided 

into cyclical 

Upper Upper units called "Suites"; 

later called 

Mcleansboro Mcleansboro "Cyclical 

Formation Formation Formations" 

Shoal Shoal 

Creek Creek 

Limestone Limestone Mcleansboro 

Formation 

rJl 

w z a: 

;::) ~ 

rJl z No. 6 coal oct oct w ~ :!E > Petersburg rJl Formation 

< z 

z Carbondale Carbondale 0 w No. 5 coal Formation Formation u Q. 

LaSalle 

Formation 

No. 2 coal 

Lower Lower 

Pottsville Pottsville Pottsville 

Formation Formation Formation 

1925. Rock strata of the Pennsylvanian System lie 

at or near the surface in 86 of the 102 counties in 

Illinois, or in about two-thirds of the total area 

(95,291 of a total 146,020 km2 ). 

Although Pennsylvanian strata of Illinois are 

commonly covered by unconsolidated Pleistocene 

glacial deposits, they are well exposed in various 

parts of the State in river valleys, stream valleys, 

and artificial cuts made during mining and construction of highways or railroads. Pennsylvanian strata 

. are also exposed along the Illinois, Kaskaskia, W ahash, Sangamon, Spoon, and Embarras Rivers, and 

other smaller rivers ~nd their tributaries. Erosion 

by streams ·emptying into the Mississippi and 

Illinois Rivers 'in western Illinois has produced 

numerous exposures. Many excellent exposures also 

occur in sbuthern Illinois beyond the limits . of 

Pleistocene glaciation. However, the single most important source of information· concerning the Pennsylvani~n System is the samples, records, and data 

at the Illinois State Geological Survey of many 

thousands of coal, oil, and water test holes. 

Wanless and Wanless Kosanke and others 

1939 1960 J. M. Weller J. M. Weller Willman and others 1932 1940 1975 

Mattoon Formation 

Cyclical units 

called 

"Cyclothems" Millersville Limestone 

Member 

Bond Formation Mcleansboro Mcleansboro Mcleansboro Shoal Creek Limestone Group Formation Group Member 

Modesto Formation 

Anvil Rock 

Sandstone Danville (No. 7 J Coal Member 

Carbondale 

Formation 

Carbondale Carbondale Kewanee Formation Group Group 

Colchester (No. 2 J Coal Member 

Palzo 

Sandstone 

Spoon Formation 

Tradewater 

Group 

Pottsville Bernadotte Sandstone 

Formation Grindstaff Member 

Sandstone Abbott Formation McCormick 

Group 

Caseyville Pounds Sandstone 

Group Member 

Caseyville Formation 

FIGURE 12.-Development of the classification of the Pennsylvanian System in Illinois (from Kosanka and others, (1960). In 

Wanless (1939) and Weller (1940), the McLeansboro and Carbondale Groups were divided into cyclothems, and the 

Caseyville and Tradewater Groups in. southern Illinois were divided into seven formations. In several reports from 1940 

to 1950, the base of the McLeansboro was put at the top of the No. 6 Coal. Cyclothems are retained in a separate cyclical classifications. Units bounding the groups and formations are in ita·lics (Willman and others, 1975). 
L22 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

BOUNDARIES OF THE PENNSYLVANIAN SYSTEM 

A major angular unconformity separates the Mississippian System from the Pennsylvanian System 

in Illinois. The configuration of the erosion· surface 

separating the two systems has been studied extens-ively by workers at the Illinois State Geological 

Survey (Siever, 1951; Wanless, 1955; and Bristol 

and Howard, 1971). They identified a series of 

broad southwestward-trending valleys as much as 

140 m deep and commonly several kilometers wide 

that evidently were formed by subaerial erosion 

(fig. 13). 

A post-Pennsylvanian, pre-Pleistocene erosion 

surface that defines the upper limit of Pennsylvanian 

deposits in Illinois. was formed by pre-Pleistocene 

stream erosion and later was modified by Pleistocene glaciation and Holocene stream erosion. Gulfian 

(Upper Cretaceous) rocks overlie Pennsylvanian 

strata in a small area in Adams, Pike, and Brown 

Counties in western Illinois. 

GENERAL CHARACTERISTICS OF PENNSYLVANIAN 

STRATA 

Pennsylvanian strata attain a maximum thickness 

of about 760 m in Wayne County, southeastern 

Illinois (fig. 14). If thickest sections are considered 

for each formation, the composite thickness of 

strata is about 1,000 m. The formations are generally thickest in southeastern Illinois and become 

thinner toward northern and northwestern Illinois. 

Som·e lower strata of the Pennsylvanian System 

are present only in southern and central Illinois and 

are overlapped by younger formations in the north. 

At some locations on the La Salle anticline, the thre·e 

lowest formations (Caseyville, Abbott, and Spoon) 

are absent and the St. Peter Sandstone (Middle 

Ordovician) directly underlies the Colchester (No. 

2) Coal, which is at the base of the Carbondale 

Formation. In the area of Rock Island and Mercer 

Counties in extreme northwestern Illinois, however, 

the three lowest formations of the Pennsylvanian 

System are well developed. -

About 90 to 95 percent of the Pennsylvanian 

Syste·m in Illinois consists of dastic rocks. Siltstone, 

shale, and underclay constitute about 40 ·percent of 

the lower part o.f the system and 65 to 70 percent of 

the middle and upper parts. In the lower part, sandstone constitutes about 60 percent of the strata; in 

the middle and upper parts, it constitutes only 

about 25 percent of the strata. Limestone is rare in 

lowermost Pennsylvanian strata but in some areas 

oonstitutes as much as 5 to 10 percent of the upper 

two-thirds of the system. Limestone is especially 1 

common in the Bond Formation, where individual 

beds as .much 15 m thick .have been recognized. 

Coal, one of the least abundant lithk units of the 

Pennsylvanian System, constitutes no mo·re than 2 

percent of rock strata in most areas. 

More than 500 units of sandstone, siltstone, shale, 

limestone, coal, and clay are distinguishable in the 

Pennsylvanian strata of Illinois (Willman and 

others, 1975). The abruptness and great number 

of verticail ·changes in lithology indicate that 

changes in depositional environment were rapid. 

Some of the coal, underclay, and limestone, although 

rather thin, are the most persistent lateral units of 

the Pennsylvanian System. If Indiana and Kentucky 

are included, several coal and limestone beds can 

readily be correlated over a distance of about 560 

km in the Illinois basin. On the basis of these marker 

beds, intervening strata that show substantial 

lateral variations can also be correlated over considerable distances. 

STRATIGRAPHY 

ABSAROKA SEQUENCE 

The Absaroka Sequence, which was named for the 

Absaroka Mountains in northeastern Wyoming and 

southern Montana, includes the Pennsylvanian System of Illinois. The base of the sequence :is the· major 

unconformity at the hase of the Pennsylvanian System in Illinois, and the top of the sequence is the 

major unconformity at the base of the Cretaceous 

System (Willman and others, 1975). The Absaroka 

Sequence, represented only by Pennsylvanian-age 

strata in Illinois, consists predominantly of clastic 

sediments and .contains numerous minor unconformities produced through erosion by deeply entrenched 

valley systems and by entrenchment o.f river distributaries in deltaic sediments. 

MORROWAN SERIES 

The type exposure of the Morrowan Ser·ies is on 

Hale Mountain, Washington County, Ark., near the 

oommunity of Morrow, for whkh the series was 

named. Both nonmarine and marine strata are included in the series. In Illinois, the Morrowan 

Series includes only the Caseyville Formation (Willman and others, 1975) (fig. 15). 

McCormick Group.-The McCormick Group in 

Illinois includes strata of the Caseyville and Abbott 

Formations, which extend from the base of the 

Pennsylvanian to the top of the Bernadotte Sandstone Member. The group derives its name from 

exposures near M.cCormick, Pope County, in southern Hlinois. The McCormick Group has a maximum 
ILLINOIS 

SUB-PENNSYLVANIAN I 

VALLEYS '-"'·""'--...---r·""'~ 1. Benton-Fairfield ~ 

2. ·Enfield / 

3. Evansville r---1.....--, 

4. Farina ______ ,-) L.. .. ,_ __ _ 

5. Gorham 

6. GrayvilleLawrenceville 

7. Inman ' 8. luka 

9. Mattoon \ 

10. Mt. Vernon- \ 

Ste. Marie --L. ____ T ____ 

11. Taylorville I 12. Toledo 

13. Vandalia 

14. Walpole 

r--J--1 --- I 

I 

I 

I 

r---L-------~:~4----J.~---: '._J 

(' 

~ 

',, ~) 

1-

'r-· 

I 

;' 

~ 

1'\ / ,, . 

',\ 

'"' _,_ .. ,.,- '"'· . .._, ... , 

-....._,., 

\:/ 

EXPLANATION, 

CHESTERIAN MAP UNITS 

• Grove Church Shale through f.'_, 

Kinkaid Formation \ 

h<<J Degonia Sandstone through \\. / 

Menard Limestone . ~ i 1 

~mmm11 WaJtersbuJY Formation through ,-)_ ____ ""' I _ 1 

·:·:·:·:·:·:·:·:·:·: Glen Dean Limestone ( f) ----i_,-... _~('·----·'\.,, k:t~:~:t~d Hardinsburg Sandstone through t

1 

( ,-~ '-., '\ 

Renault Limestone \ ( / ... _ ,....._ 

\ ( ,' "---.. ... __ '! \ 

\ [\"'v/ "' j ) 

\,~ \\ '----

FIGURE 13.-Paleogeologic map of sub-Pennsylvanian Chesterian surface in Illinois (from Howard, in 

press). 

L23 
L24 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

EXPLANATION 

-36o- lsopach---<ontour interval 

60 meters 

' Small outlier 

E Eroded 

OE:::::::=::r:==:::E20~:::r::::=::j40 MILES 

0 20 40 KILOMETERS f"":3 t==:1 I 

FIGURE 14.-Thickness of the Pennsylvanian Sy.stem. 

area 
ILLINOIS L25 

thickness of at least 180 m in ·southern Illinois, 

but it thins northward to about 60 m and is absent 

in large areas of western and northern Illinois. The 

McCormkk Group consists of about 50 to 60 percent sandstone, about 40 percent or more sandy 

·shale, and a few thin nonpersistent limestones and 

coals. The sandstones ·commonly form cliffs, are extensively cross bedded, and contain a. high percentage o.f quartz. 

The McCormick Group is predominantly devoid o.f 

animal fossils, although a few calcareous sandstones 

and shale zones and one limestone mem:ber that .contain marine 'invertebrate fossi.ls .have been recognized. Log ··casts of Lepidodendron sp., Calamites 

sp., and Sigilla·ria sp. are common in fine-grained 

sandstone· of the lower part o.f the McCormick 

Group. 

Caseyville FormaUon.-The Caseyville Formation 

was named by Owen ( 1856, p. 48) for the community of Caseyville on the Ohio River in southwestern 

Union County, Ky., which is near the site of the 

ty.pe locality. Rock •sections for definition o.f the 

formation were "measured from outcrops on the 

Illinois shore of the Ohio River between the mouth 

of the Saline River and Gentry's Landing below 

Battery Rock" in Hardin County (Lee, 1916, p. 

15-16). Strata from the base of the Pennsylvanian 

System to the top of the Pounds Sandstone Member 

are included 'in the Caseyville F-ormation. 

The Caseyvi.Ue Formation is commonly about 100 

m thick in southern Illinois. Where the formation 

has filled pre-Pennsylvanian bedrock valleys, it may 

be as much as 150 m thick. The Caseyville Formation was deposited only in southern and southeastern 

Illinois and in parts of Mercer and Rock Island 

Counties in northwestern Illinois, where it locally 

attains a thickness of more than 30 m (fig. 16). It 

is overlap·ped by the Abbott Formation; maximum 

combined thickness of the Caseyville, Abbott, and 

Spoon Formations in southern Illinois is more than 

360 m (fig. 17). 

Sandstone is the most common constituent of the 

Caseyville Formation, but the formation also contains abundant siltstone and shale. Because o.f local 

variations in lithology, ind-ividual beds of the formation ·Can usually be traced only for short distances. 

The sandstones are ·predominantly quartzos·e and 

contain very little clay or mica. Quartz granules 

and pebbles, usually less than 12 mm in diameter, 

are scattered throughout the sandstones and may 

be in local deposits of conglomerate. Individual 

sandstones may be as ·much as 30 m thick and 

commonly display prominent, rather uniform crossbedding with dip to the west, south, or southwest, 

parallel to the direction of elongation of the sand 

bodies (Willman and others, 1975). 

Shale, silt shale, and siltstone beds are common in 

the Caseyville Formation. Most are medium to dark 

gray where unweathered and orange .brown on 

weathered surfaces. Coarse siltstone and fine-grained 

sandstone beds are commonly ripple bedded. Shale 

associated with the coals is usually dark. In northwestern Illinois, the Caseyville is composed of 

medium-gray to dark-gray brittle shale interbedded 

with silty shale and, in a few places, a clean quartz 

sandstone. 

Although several thin and lenticular coals are 

present in the Caseyville Formation, only the Gentry 

Coal Member of southeastern Illinois has been 

named. At least seven impure coals that are individually as much as 60 em thick have been recognized in the Caseyville Formation o.f Rock Island 

and Mercer Counties. 

The Caseyville Formation, in contrast with 

younger Pennsylvanian strata, contains almost no 

l-imestone beds. The Sellers Limestone Member, 

which is known fro·m only one exposure near Sellers 

Landing, Hardin County, Ill., on the west bank of the 

Ohio River, is the only named limestone member; 

it contains a variety of invertebrate marine fossils. 

Other recognized members o.f the Caseyville Formation are the Lusk Shale, the Wayside Sandstone, 

the Battery Park Sandstone, the Drury Shale, and 

the Pounds Sandstone. 

The Caseyville Formation of Illinois is correlative with the lower part of the Mansfield Formation 

of Indiana and all but the upper 1 or 2 m o.f the 

Caseyville Formation of Kentucky. Three State 

parks in southern Illinois and several parks in 

western Kentucky and Indiana are in Caseyville 

outcrop areas of outstanding natural beauty. The 

high sandstone cliffs and associated rugged topography form so~e of the most scenic areas o.f the 

Midwest. 

ATOKAN SERIES 

The Atokan Series in Illinois includes only !strata 

of the Abbott Formation of the McCormick Group. 

The lower and upper boundaries o.f the series are 

established at the top of the Pounds Sandstone 

Member and the top of the Bernadotte Sandstone 

Member, respectively. Although fossil-bearing strata 

are present in the Atokan Series in Illinois, they 

are not used to define its boundaries (Willman and 

others, 1975). 
L26 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

~~ e CENTRAL AND NORTHERN AND EASTERN AND (1)'- LL SOUTHERN WESTERN SOUTHEASTERN 

~ .E Greenup Limestone 

Woodbury Limestone ! i CD C:: 

Gila Lir!lestorie (I) "' 

Reisner Limestone 

z 

~ Bogota Limestone 

Cl = 

a: 

> Trowbridge Coal 25 

c Effingham Limestone 

8 

ti 

:E 50 METERS 

Shumway Limestone 

Q.. Omega· Limestone Bonpas Limestone 

::l Calhoun Coal Calhoun Coal 

0 

a: Shelbyvile Coal (!) 

0 Opdyke Coal Merom Sandstone (E) a: Dix Limestone 

0 McDeary's Bluff Coal (SE} 

lXI Cohn Coal Cohn Coal (E) C/) 

z z Friendsville Coal (SE} 

~ Millersville Limestone Livingston Limestone (EJ 

<( 

w a: 

-1 ::I Coffeen Limestone 0 u (/) witt Coal Reef Limestone 

.::!: (/) -c 

c Rat Creek Coal Aannigan Coal :E 0 Bunje Limestone (SW} II) 

Sorento Limestone Little Vermilion Limestone· 

McWain Sandstone Mt. Carmel Sandstone 

Shoal Creek Limestone La Salle· Limestone Shoal Creek Limestone 

New Haven Coal New Haven Coal 

Macoupin Limestone Hall Limestone Macoupin Limestone 

Womac Coal Womac Coal 

Burroughs Limestone (SW} Inglefield Sandstone 

Carlinvale Limestone 

Cramer Limestone Cramer Limestone 

Chapel (No. 8) Coal Chapel (No. 8) Coal Chapel (No. 8) Coal 

Trivoli Sandstone Trivoli Sandstone Trivoli Sandstone 

z 0 

"Iii <( Cl) Scottville Limestone Exline Limestone T -c 

(/) 0 Athensvile Coal (SW) 

w :E 

z Lake Creek Coal (S) Lonsdale Limestone 0 West Franklin Limestone. 

:E · Pond Creek Coal (SJ Gimlet Sandstone _L (/). Rock Branch Coal (SW) 

w De Graff Coal (Sj 0 

t Piasa Lim est one Farmington Shale 

FIGURE 15.-Classifica tion of the Pennsylvanian --Sys-tem;-·-ln-the-g.rn.phic.....col.u_mll,_"l!!~.mk space indicates gray shale. 

Named members are listed to the right of the graphic· column.- · · -- -

Abbott Formation.-The type section of the Abbott Formation of the McCormick Group is defined 

from exposures near Abbott Station on the Illinois 

Central Gulf Railroad, Pope County, Ill. Only the 

prominent s~andstones and some coals of the Abbott 

Formation have been' named. Because the bordering 

sandstone members may be missing locally, hoth the 

top and the base of the Ahbott Formation are commonly difficult to identify in the subsurface. 

The Abbott Formation overlaps the Caseyville 

Formation and is the basal Pennsylvanian formation throughout much of Illinois. The Abbott is overlapped by the Spoon Formation in northern and 

northeastern Illinois and on some prominent anticlinal structures. Thickness of the Abbott Formation ranges from a maximum of 100m in southern 

Illinois to less than 30 m in western Illinois. 

The Abbott Formation is a transitional unit between the underlying Cas·eyville Formation and 

younger strata. Basal sandstones of the Abbott 

.closely resem,ble those of the Caseyville Formation, 

whereas middle and upper Abbott sandstones are 

generally thinner, contain more interstitial day and 

mica; and contain no more than a few quartz 
lLLINOIS L27 

SOUTHWESTERN AND NORTHERN AND EASTERN. WESTERN 

Danville (No. 7) Coal ·oanville (No. 7) Coal . Danville (No. 7) Coal 

Galum Limestone 

Allenby Coal 

Bankston Fork Limestone Bankston Fork Limestone 

Anvi Rock Sandstone Copperas Creek Sandstone 

Lawson Shale · 

Conant Limestone Conant Limestone 

Jamestown Coal Jamestown Coal 

Brereton Limestone Brereton Limestone Brereton Limestone 

Anna Shale Anna Shale Anna Shale 

Herrin (No. 6) Coal Herrin (No. 6) Coal Herrin (No. 6) Coal 

Spring Lake Coal 

Big Creek Shale Vermiionvile Sandstone 

Briar Hill (No. 5 A) Coal f!Jia,.ffil (No. SA) Coal 

Canton Shale Canton Shale Geinon Shale St. David Limestone St. David Limestone St. David Limestone 

Dykersburg Shale Harrisburg (No. 5) Coal ·Springfield (No. 5) Coal Harrisburg (No. 5) Coal 

Covel Conglomerate 

a.. Hanover Limestone Hanover Limestone 

Excello Shale Excello Shale Excello Shale :J Summum (No. 4) Coal Summum (No.4) Coal Summum (No. 4) Coal 

0 z Roodhouse Coal Breezy H II Limestone 

a: :!: Kerton Creek Coal 

(!) Pleasantview Sandstone Pleasantview Sandstone Pleasantview Sandstone (/) 

w Purington Shale Shawneetown Coal w z Shawneetown Coal Lowell Coal 

w 0 Oak Grove Limestone Oak Grove Limestone 

z. ·~ Mecca Quarry Shale ~t~c~r~~r~a~~~ne Mecca Quarry Shale 

<t (/) 

~ w Francis Creek Shale 0 Cardiff Coal 

w Colchester (No. 2) Coal Colchester (No. 2) Coal Colchester (No. 2) Coal 

~ Browning Sandstone 

Palzo Sandstone :~neV~ann~:~ne 

Seelyvile Coal Seelyvile Coal 

· De Koven Coal Greenbush Coal 

Davis Coal Wiley Coal 

Seahorne Limestone Seahorne Limestone Vergennes Sandstone. 

Stonefort Limestone 

Wise _Ridge Coal 

Mt. Rorah Coal De Long Coal 25 

Creal Springs Limestone 

Murphysboro Coal 

Granger Sandstone 

Brush Coal 50 METERS 

Hermon Coal Seville Limestone 

Rock Island (No. 1) Coal 

Berriadotte Sandstone 

·Rocks present only in subsurface. 

Delwood Coal Pope Creek Coal Local o~·field names h&Ye been used informally. 

z 

< 

:.;: Finnie Sandstone 

0 walis Coal Tarter Coal 1-

< Manley Coal a.. 

:J Grindstaff SandStone Babylon Sandstone 0 

a: Reynoldsburg Coal (!) 

~ Pounds Sandstone u 

~ CD Gentry Cool (southeast) :! a: II) 

t' 0 z ~ Sellers Limestone (southeast) 

u < 0 u 3: ·~ 0 

a: 25 

a: Battery Rock Sandstone 

O· 

~ 

50 METERS 

FIGPRE 15.--Continued. 
L28 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

EXPLANATION 

Q Boundary of Pennsylvanian System 

0 20 40 MILES 

E3 E""3 

o' 20 40 KILOMETERS 

t=1 t=1 I 

FIGURE 16.-Extent of the Caseyville Formation (from Wanless, 1955). 
EXPLANATION 

-180- Isopach-contour interval 

60 meters 

F:::::::::}::::] Outcrop area 

.. Small outlier 

E Eroded 

0 20 40 MILES 

0 20 40 KILOMETERS 

E3 E3 I 

ILLINOIS 

FIGURE 17.-Combined thickness of the Caseyville Formation (from Wanless, 1955). 

L29 
L30 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

granules and pebbles. Coals are generally thicker 

and more .persistent in. the Abbott Formation than 

in the underlying Caseyville but not as well developed or extensive as in younger formations. The 

uppermost sandstones of the Abbott Formation are 

siniilar to the r·elatively impure sandstones of the 

overlying Spoon Formation. 

Named members of the Abbott Formation are the 

Reynoldsburg Coal, Grindstaff Sandstone, Babylon 

Sandstone, Manley Goal, Willis Coal, Tarter Coal, 

Finnie Sandstone, Delwood Coal, and Pope Creek 

Goal. The Abbott Formation is equivalent to the 

upper part of the Mansfield and virtually all the 

Brazil Formation of Indiana, and to the· upper 1 

or 2 m of the Caseyville Formation and the lower 

part of the Tradewater Formation in western 

Kentucky. 

DESMOINESIAN SERIES 

The Desmoinesian Series comprises the Spoon and 

Carbondale Formations of the Kewanee Group and 

the lower part of the Modesto Formation of the 

McLeansboro Group. 

Kewanee Group.-The Kewanee ·Group consists of 

the Spoon and Carbondale Formations and is named 

for Kewanee, Henry County, in western Illinois, 

where the two formations are well exposed. The 

Kewanee ·Group overlies the Abbott Formation in 

normal sequence, but in northern and northeastern 

Illinois, where the Abbott is missing, the unit lies 

on strata ranging in age from. Valmeyeran (Middle 

Mississippian) to Champlainian (Middle Ordovician). 

More than 99 percent of the mapped coal reserves 

of Illinois are contained in the Kewanee Group. The 

well-developed cyclothems and the broad extent of 

many relatively thin lithologic units (marine limestone, black fissile shale, coal, and underclay) are 

distinctive of the Kewanee Group. 

Spoon Formation.-The Spoon Formation of the 

Kewanee Grou1J is defined from exposures in a road 

and railroad cut in western Fulton County, Ill. 

(NW1,4 sec. 22, T. 6 N., R. 1 E.), near the 8poon 

River, from which the name of the formation is 

derived. The base of the formation is defined as the 

top of the Bernadotte Sandstone of western Illinois 

or the Murray Bluff Sandstone of southern Illinois. 

The upper boundary of the formation is the base of 

the Colchester (No. 2) Coal (fig. 12). The formation is as much as 100 m thick in southern Illinois, 

but it thins substantially in northern and western 

Illinois, where it ranges from 1 or 2 m to less than 

30 m in thickness. The lowermost extensive limestones and coals of the Pennsylvanian System are 

in the Spoon Formation, but they are generally 

thinner than similar units of overlying Pennsylvanian strata. The sandstone of the Spoon Formation contains more mica and day than the sandstone of the underlying Abbott Formation and reflects a gradual decrease in ·sediment maturity that 

is continued in younger Pennsylvanian strata. The 

coals are neither as thick nor as persistent as those 

of the Carbondale Formation but are markedly 

thicker and more extensive than those of the Abbott 

Formation. The Spoon Formation correlates with 

the uppermost part of the Linton Formation in Indiana and with the U1Jper part of the Tradewater 

Formation and the lower part of the Carbondale 

Formation in western Kentucky. The named members of the formation include 18 coals, 5 limestones, 

and 5 sandstones (fig. 15). 

Carbondale Formation.-T.he Carbondale Formation of the Kewanee Group is named for Carbondale, 

Jackson County, Ill., which is near outcrops of the 

formation in southern Illinois. Three outcrops in 

Fulton County, western Illinois (SE1,4NE1,4 sec. 1, 

T. 7 N., R. 4 E.; NW%,NE1,4NW1,4 sec. 20, T. 8 N., 

. R. 3 E.; and SW. cor. sec. 21, T. 8 N., R. 3 E.) were 

established by Kosanke and others (1960, p. 34 and 

46) as the type sections for the formation. The base 

of the Colchester (No·. 2) Coal is defined as the base 

of the .Carbondale Formation, and the top of the 

Danville (Nn. 7) Coal marks the upper boundary. 

The gray silty shales and sandstones display 

abrupt lateral variations in thickness and are largely 

responsible for variations in thickness of strata. between the coals and other persistent units. The formation is more than 120 m thick near outcrop areas 

in southern Illinois but is less than 45 m thick in 

western and northeastern Illinois (fig. 18). 

Sandstones of the Carbondale Formation commonly are deposited in elongated channel systems 

and may be as much as 30 m thick. Thinner sheettype deposits are also common. The sandstones, 

which are slightly more argillaceous than sandstones of the Spoon Formation, are classified as subgraywackes. Gray silty shale is the most abundant 

rock unit in the Carbondale Formation. Sideritic 

nodules and bands are abundant in the shales. The 

relatively thin but widespread marine limestones 

are gray to dark gray, argillaceous, and fossiliferous. Black fissile shales, usually less than 60 em 

thick, are associated with the marine limestones and 

commonly contain a marine- to brackish-water invertebrate fauna similar to that in the limestones. 

A light gray, nodular limestone, usually devoid of 
EXPLANATION 

-60- Isopach-contour interval 

7.5 meters 

I\%\\\}\\\\\%J Outcrop area 

E Eroded 

0 20 40 MILES 

0 20 40 KILOMETERS 

EE33=EE33:::J 

ILLINOIS 

E 

FIGURE 18.-Thickness of the Carbondale Formation (Willman and others, 1975). 

L31 
L32 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

marine fossils, occurs in the basal part of the widespread underclays. 

The principal coals of Illinois, the· Herrin (No. 

6), the Springfield-Harrisburg (No. 5), the Colchester (No. 2), and the Danville (No. 7), listed 

in order of economic importance, are within the 

Carbondale Fo·rmation. The lower 15 m of the 

Sturgis Formation and the upper part of the Carbondale Formation of western Kentucky correlate 

with the Carbondale Formation. In Indiana, approximately the same interval of strata as in Illinois 

is assigned to the Carbondale Formation. The named 

members of the formation in Illinois include 14 

coals, 9 limestones, 9 shales, 5 sandstones, and 1 

conglomerate (fig. 15). 

McLeansboro Group.-The McLeansboro Group 

consists of thr,ee formations-the Modesto, Bond, 

and Mattoon-and includes all Pennsylvanian strata 

in Illinois above the top of the Danville (No. 7) 

Coal, which is the base of the group. The group is 

named for the city of McLeansboro, Hamilton 

County. The type section consists of 247 m of Pennsylvanian strata in a diamond drill core from a test 

hol·e near McLeansboro (SE1/t.SW%,SW14NE1!t. sec. 

25, T. 4 S., R. 5 E.). An additional 120 m of strata 

younger than those in the type section drill hole 

have been recognized in the deeper part of the 

Illinois basin in J asp,er County, and still younger 

strata have been identified in western Kentucky. 

Coals of the McLeansboro Group· are gene·rally 

thinner and less extensive than those of the Kewanee 

Group. Coals as thick as 1 m have been reported, 

although most are less than 30 em. thick. Limestones 

are generally thicker, more numerous, more predominantly marine, and less argillaceous than those 

of the Kewanee Group. Rock strata of the McLeansboro Group are also known by the same name in 

Indiana and correlate with all but the lowest part 

of the Sturgis Formation of Kentucky. 

Modes to Formation.-The type locality for the 

Modesto Formation comprises four outcrops described by Payne (1942) and Ball (1952) near 

Modesto, Macoupin ·County, where nearly all of the 

formation is exposed. The base of the Modesto Formation is the top of the Danville (No. 7) Coal, and 

the formation extends to the base of the Shoal Creek 

Limestone Member or La Salle Limestone Member. 

The Modesto Formation is about 140 m thick in 

southern Illinois but thins to about 60 m in northern Illinois and to less than 40 m in the vicinity of 

the La Salle anticline in east-central Illinois (fig. 

19). The coals of the Modesto Formation are generally thinner than those of the underlying Carbondale Formation, but are widespread. The limestones are generally thicker and less argillaceous, 

and some are commonly associated with red claystone and shale. Much of the Modesto Formation 

consists of gray shale, although channel sandston~ 

dep-osits are as much as 24 m thick in some areas. 

The Modesto Formation correlates with part of the 

Sturgis Formation of western Kentucky and the 

Patoka Formation of Indiana. The named members 

of the formation include 8 coals, 10 limestones, 3 

sandstones, and 1 shale (fig. 15). 

MISSOURIAN SERIES 

The Missourian Series of the Pennsylvanian System is named for the State of Missouri and includes 

rocks in Illinois from the top of the Trivoli Sandstone Member to a position 1 or 2 m below a coal 

that underlies the Shumway Limestone Member. 

The upp·er part of the Modesto Formation, all the 

Bond Formation, and about half of the Mattoon 

Formation are included in the Missourian Series. 

Bond Formation.-The Bond Formation of the 

McLeansboro Group is named for Bond County in 

southwestern Illinois. Seven separate outcrops in 

Bond, Christian, and Montgomery Counties constitute the type section. The Bond Formation averages about 75 m thick; it ranges in thickness from 

less than 45 m in eastern Illinois to m.ore than 90 

m in southeastern Illinois (fig. 20). The base of the 

Bond Formation is defined a.t the base of Shoal 

Creek Limestone Member, or the La Salle Limestone 

Member, and its upper boundary is the top of the 

Millersville or Livingston Limestone Member. Substantial parts of the formation consist of calcareous 

clays and limestone. The bounding limestone members are the thickest and include the purest limestones in the Pennsylvanian System of Illinois. The 

upper limestone is as much as 15 m thick and the 

lower limestone is locally as much as 9 m thick; 

both are extensively quarried. Gray shale is the most 

abundant lithic constituent of the formation, but 

thick channel sandstones are also abundant locally. 

Red claystones and shales occur in the Bond Formation and are best developed in northern Illinois. 

The formation correlates with a part of the Sturgis 

Formation in western Kentucky and is also called 

"Bond" in Indiana. The named members of the formation include nine limestones, three coals, and two 

sandstones (fig. 15). 

VIRGILIAN SERIES 

The Virgilian Series of the Pennsylvanian System 

consists of all strata above a position 1 or 2 m below 
EXPLANATION 

-60- Isopach-contour interval 

7.5 meters 

l\\\[\[\[f\\[[\\\%1 Outcrop area 

E Eroded 

0 20 40 MILES 

EE3=3::~--::EE3=3:=:J 

0 20 40 KILOMETERS 

E3 E3 I 

ILLINOIS 

E 

FIGURE 19.-Thickness of the Modesto Formation (Willman and others, 1975). 

L33 
L34 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

EXPLANATION 

--45- Isopach--contour interval 

7.5 meters 

[\:\]\:\]\\\:\:d Outcrop area 

E Eroded 

0 

0 20 

E3 E3 

E 

E 

FIGURE 20.-Thickness of the Bond Formation (Willman and others, 

1975). 
ILLINOIS L35 

the coal that is just below the Shumway Limestone 

Member. It includes the youngest Pennsylvanianage rocks in Illinois. 

Mattoon Formation.-The Mattoon Formation of 

the McLeansboro Group is named for the city of 

Mattoon, Coles County, Ill., which is located in the 

general outcrop area of the formation. The base of 

the formation is the top of the Millersville o·r Livingston Limestone Member; its upper boundary is 

an erosion surface largely covered by Pleistocene 

glacial deposits. No type section has been designated 

for the formation. A reference section for the lower 

90 m of the formation has been defined in Illinois 

State Geological Survey Control Well 191, an oil 

test boring from Clay County on file at the Survey 

(Kosanke and others, 1960, p. 49, 83, and 84). The 

greatest thickness of strata of the Mattoon Formation in Illinois, slightly more than 180 m., is in 

Jasper County in the central part of the Illinois 

basin (fig. 21) . 

The Mattoon Formation consists la.rgely of thick 

gray shales, several well-developed sandstones, black 

fissile ~hales, limestones, coals, and underclays. Most 

geologic data on the formation are derived from 

drill holes, since outcrops are widely scattered and 

exposed sections are relatively thin. The limestone 

units and coals of the Mattoon Formation are believed to be at least as persistent as others of the 

McLeansboro Group, but their extent cannot be determined from the limited information available. 

Several tan argillaceous limestones less than ll/2 m 

thick contain only ostracodes and spirorbis. Others, 

including the Omega and Greenup Limestone Members, contain abundant marine fossils and are 

moderately thick. 

The Mattoon Formation is equivalent to the upper 

part of the Sturgis Formation in Kentucky, but 

more than 200 m of strata younger than the youngest Mattoon rocks are present in the Sturgis Formation. The lowermost 45 m of Mattoon strata extend into Indiana. The named members of the formation include 10 limestones, 7 coals, and 1 sandstone (fig. 15). 

CYCLOTHEMS IN ILLINOIS STRATIGRAPHY 

The first clear description of cycles of strata that 

are now termed "cyclothems" was presented by 

Udden (1912) for an area in western Illinois n~ar 

Peoria. He recognized a succession of strata, including coal, which was repeated almost perfectly 

four times. Subsequent s~tudies indicated that repeated sequences of sedimentary strata characterize 

large parts of the Pennsylvanian System from at 

least western Pennsylvania to northern Texas. 

These sequences were first referred to simply as 

"cycles of sedimentation" by Udden (1912) and 

Weller (1930, 1931). Wanless and Weller believed 

a special term was needed for these cycles and in 

1932 (p. 1003, footnote) proposed the term "cyclothem" to designate "a series of beds deposited during a single sedimentary cycle of the type that prevailed during the Pennsylvanian Period." The term 

won immediate acceptance and was soon in widespread use. 

Although the idealized cyclothem sequence (fig. 

22) is rarely complete, the units that are present 

retain the same relative position in sequence. Cyclothems have their greatest use in Illinojs stratigraphy 

in aiding determination of the genetic significance 

of units and in detailed correlation and field mapping of Pennsylvanian strata. 

The cyclothem was removed from the rock-stratigraphic classification of the Illinois State Geological 

Survey in 1960 (Kosanke and others, 1960) and is 

now included as a separate cyclical classification. 

PALEONTOLOGY 

Most information concerning paleontology of the 

Pennsylvanian System has been obtained from limestone, coal, black carbonaceous shale, and underclay 

lim·estone. Sandstone and siltstone locally may contain plant impressions and fragments, but are commonly nonfossHiferous. 

The most common invertebrate macrofossils are 

brachiopods, crino,id.s, gastropods, and pelecypods. 

Corals, cephalopods, trilobites, foraminifers, bryozoans, and worms are also present. Biostratigraphic 

zones in the Pennsylvanian in Illinois are based on 

fusulinids, ostracodes, and spores. Floral zones for 

Illinois and other parts of the United States were 

described by Read and Mamay (1964). 

Coal-bearing Pennsylvanian strata of Illinois 

have been fairly precisely correlated from spores 

and pollen in the coals. Palynological studies of 

other lithologic units have not been extensive, however. Major time-stratigraphic intervals are delineated by their most abundant spore taxa and by 

the occurrrence of certain genera ·and species that 

have relatively short stratigraphic ranges. Coals in 

the Illinois basin can generally be closely correlated 

by the study of spores. 

MORROW AN SERIES 

Marine fossils are rare in the Morrowan Serie~ 

of Illinois, but a Morrowan fauna has been recog-
L36 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

EXPLANATION 

-150- Isopach-contour 

interval 30 meters 

E Eroded 

0 20 

0 20 

E3 E3 

E 

E 

~~----~--~-----+-----,----~ 

FIGURE 21.-Thickness of the Mattoon Formation (Willman and others, 1975). 
ILLINOIS L37 

Shale-Gray, sandy at top; contains marine fossils and 

sideriti.c concretions, particularly in lower part 

Shale-Black, hard, fissile; contains large spheroidal 

concretions and marine fos_sils 

,___. _ _.__.....A.4 limestone -Contains marine fossils 

Shale-Gray, silty; pyritic and sideritic concretions and 

plant fossils common at base; marine fossils rare 

Coa~locally contains claystone or shale partings 

Underclay-Gray, darker at top, calcareous in lower part 

limestone-Argillaceous, commonly nodular or in 

discontinous beds 

Shale-Gray, sandy 

Sandstone-Fine grained, micaceous; occurs as 

nonchannel ripple-bedded facies gradational at base, 

or as channel facies with erosional base 

FIGURE 22.-Arrangement of lithologic units in a cyclothem 

(from Willman and Payne, 1942). 

nized in an exposure o.f the Sellers Limestone Member in southeastern Illinois. 

The compression plant fossils, N europteris tennesseeana and Mariopteris pygmaea of the Morrowan Series are in Zone 6 of Read and Mamay 

( 1964). The roof shale of the Baldwin coal, which 

occurs in the Morrowan type section of Arkansas, 

contains a plant-impression flora similar to that 

above the Gentry Goal Member in southeastern Illinois. The relative ages of strata within the Morrowan Series in Illinois can best be determined from 

spores, which are abundant in Morrowan Series 

rocks of Illino,is, especially in the coals. The Morrowan Series is dominated by the genus Lycospora, 

which in some coals .constitutes as much as 80 percent o.f the spore population. Spores of herbaceous 

lycopods-Densosporites, Cristatisporites, and Radiizonates-are also abundant. 

ATOKAN SERIES 

W.here marine rocks are abundant, the Atokan 

Series is commonly characterized as the two subzones of the earliest fusiform fusulinids, Profusulinella and Fusulinella, and the top is defined as the 

strata below the first appearance of Fusulina and 

W edekindellina; .some confusion has developed because Fusulina has been reported in the Atokan of 

the ty,pe area in Arkansas. 

Plant fossils for the Atokan Series are in Zone 

7, Megalopteris spp. and in Zone 8, Neuropteris 

tenufolia of Read and Mamay (1964). Spore assemblages are the best means for correlating the Atokan 

strata in Illinois with Atokan strata of other areas. 

They are of greater diversity and their genera are 

more abundant and more evenly distributed than in 

the Morrowan Series. Laevigatosporites, Calamites, 

Florinites, and Punctatisporites increase in the upper part at the expense of Lycospora, which with 

Densosporites-especially D. annulatus and Cristatisporites indignibundus-is common in the lower 

part of the Atokan. Certain species of Radiizonates 

and Torispora are useful in defining the upper part. 

DESMOINESIAN SERIES 

Fusulinids are abundant in many of the limestones 

in Illinois, and the Desmoinesian Series is defined as 

the Fusulina Zone. Fusulina is confined to the Des-

.moinesian Series except for one reported occurrence 

in Atokan rocks of Arkansas. Several other invertebrates, such as M esolobus, Chaetetes, and Prismopora, are seldom found above the top of the Desmoinesian, and certain of their species are confined to this series. The upper boundary is difficult 

to determine in much of Illinois, because an interval 

at the top o.f the Desmoinesian and the base o.f the 

Missourian is barren of fusulinids. 

N europteris 'tarinervis in Floral Zone 9 and 

Neuropteris flexuosa and Pecopteris spp. in Zone 10 

of Read and Mamay (1964) are included in the Desmoinesian Series. In Illinois, this series ·Contains the 

thickest and most widespread coals, and Lycospo'ra 

is the dominant spore. This genus abruptly disappears at the top of the Desmoinesian. Thymospora 

pseudothiessenii, which appears in the bottom third, 

also disappears at the top of the Desmoinesian. 

Densosporites occurs only in the lower half of the 

Desmoinesian, and Schopfites is diagnostic of approximately the middle third. A marked ·change in 

the spo.re flora is found at the Desmoinesian-Missourian boundary. 
L38 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

MISSOURIAN SERIES 

The Missourian Series is characterized by earlier 

forms of the genus Triticites, which is the subgenus 

Kansanella of Thompson. Floral zones are not as 

well defined in Illinois; where the Missourian and 

the overlying Virgilian together constitute Zones 

11 and 12 (zone of Odontopteris sp.) (Read and 

Mamay, 1964). Delineation of the ranges of spore 

taxa in the Missourian and Virgilian Series has not 

been determined with the same degree of accuracy 

as in the remainder of the Pennsylvanian because 

the stratigraphic relation of many of the coals has 

not been worked out in detail. Small spores of ferns 

and seed ferns, many less than 30 ~-tm in diameter, 

are prolific in most of the Missourian and Virgilian 

coals. The taxa are ·Classified as Punctatisporites 

minutus, Laevigatosporites minut1ts, and .species of 

Cyclogranisporites and Apicu,latisporis. Endosporites is abundant in many of the coals. 

VIRG ILIAN SERIES 

The Virgilian Series includes strata containing 

fusulinids of the genus Triticites that are more advanced than the subgenus Kansanella found in lower 

strata. The upper limit is .placed just below the first 

appea.rance of the Permian genera Pseudoschwagerina and (or) Schwagerina, but neither have been 

found in the Illinois basin. The spores and plantcompression fossils 'in V·irgilian rocks of Illinois 

are not well known. 

ENVIRONMENTS OF DEPOSITION 

Pennsylvanian-age strata of the Illinois basin 

were deposited in a slowly subsiding trough that 

remained open to the south until post-Pennsylvanian 

time. The trough was bounded on the east by the 

Cincinnati arch and on the .southwest by the Ozark 

uplift. The present dosed basin was formed through 

uplift of the Pascola arch after close of the Pennsylvan!a.!l Period and sometime prior to late in Cretaceous time, as indicated by the presence of late 

Cretaceous strata of the Gulfian Series in southern 

Illinois, which unconformably overlie uplifted Pennsylvanian strata. . 

At the beginning of Morrowan time, the area 

that is now the Illinois basin was crossed by a series 

of southwestward flowing streams whose valleys 

were cut to depths as much as 140m. below adjacent 

uplands (fig. 13). These streams deposited large 

quantities of dastic .sediments of the Caseyville Formation in the southern part of the Illinois basin, 

which was then open to the south. Medium- to 

coarse-grained sandstone containing s·cattered white 

quartz pebbles was deposited .in the stream channels, which apparently underwent substantial lateral 

shifting of •position during sedimentation. Mudstone, siltstone, and shale were deposited on floodplains adjacent to ·channels and also in lakes, 

marshes, and deltas. 

Sandstone of the Caseyville Formation is highly 

quartzose and was evidently derived from reworked 

older Paleozoic strata. Distinctive characteristics of 

the Caseyville Formation are extreme local variability of strata and the predo·minance of mediumand coarse-grained ·clastic deposits. 

Both channel-fill and sheetlike sandstones were 

deposited in Illinois during the Atokan Epoch. The 

channel sandstone apparently filled numerous fluvial 

and distributary channels of deltas. Crossbedding 

orientations suggest that most coarse clastic deposits 

were derived from an easterly source. Sheetlike 

sandstone may have been deposited largely as interdistributary sands of deltas, or as upper delta plain 

deposits. The Bernadotte Sandstone Member of 

western Illinois is a typical sheetlike sandstone that 

contains abundant root (Stigmaria) impressions; 

this indicates that it served as a soil for vegetation 

that produced the Rock Island (No. 1) Coal. Darkgray ·mudstones of both northwestern and southern 

Illinois contain clay ironstone concretions and appear to have formed in inter-distributary bays and 

lagoons. Atokan-age sediments show a progressive 

increase in clay and mica content; this indicates that 

source areas may have been stripped of sedimentary 

cover and that micaceous metamorphic rocks were 

supplying detritus. 

Minor marine transgressions occurred only in the 

eastern part of the Illinois basin during Atokan 

time. The Fulda and Ferdinand Limestone Members 

of the Mansfield Formation in Indiana and at least 

two unnamed limestone beds in western Kentucky 

were deposited in these seas. No equivalent strata 

are known in Illinois. 

Depositional environments of the Desmoinesian 

Epoch refle.ct a marked transition from relatively 

irregular fluviatile-deltaic process·es to remarkably 

uniform regional cycles in which nearly identical 

depositional environments extended without interruption for hundreds of kilometers, virtually the 

full extent of the Illinois basin at times. During 

Desmoinesian time, more marine transgressions occurred in the Illinois basin than in the Appalachians, 

and more nonmarine strata were deposited than in 

areas to the west (Wanless, 1975, p. 85). Accordingly, the nature and variability of Pennsylvanian 

System cyclic sedimentation is better developed in 
ILLINOIS L39 

the Illinois ·basin than elsewhere in the United 

States. 

Because the trans,gressions and regressions were 

relatively uniform, a single generalized depositional 

sequence that characterizes depositional environments of much of the Desmoinesian Epoch in the 

Illinois bes:in was described by Wanless (1975, p. 

85). 

Beginning with a time of maximum transgression, marine lime mud was deposited eastward from 

northern Missouri and Iowa into .the Illinois basin; 

where it graded laterally into clay muds of a broad 

gently sloping shoreline that may have extended 

nearly parallel to the Cincinnati arch. At numerous 

point.s landward from the shoreline, streams fed 

clastic deposits into shallow seas and buried the 

recently deposited lime mud; construction began 

of a broad platform of interassociated prodelta and 

deltaic deposits on which a large coal swamp would 

later be established. Basal deposits of this unit were 

commonly phosphatic nodules and some fossil detritus, which graded upward into dark shale and 

fine, evenly laminated siltstone. 

In some areas, mud of the advancing shelf-deltaic 

complex was eroded by river distributaries, and 

streams later filled some of the eroded channels with 

sand. As the constructional period ended, the broad 

shelf probably stood at or near sea level. Vegetation 

developed on exposed clay or sand and in shallowwater areas. In extensive areas where the water 

table was sufficiently high, peat accumulated. 

Closely following peat accumulation in some parts 

of the Illinois basin was the deposition of irregular 

bodies of gray mudstone or shale. This deposition 

preceded the reestablishment of a complex marine 

environment. The gray shale occurs in lenses and 

pods, which in some areas apparently are randomly 

distributed but elsewhere are adjacent to large 

fluvial distributary channels. The gray shale bodies 

show evidence of erosion prior to burial by overlying marine strata. The lowermost 1 or 2 m of the 

gray shale locally contain impressions and casts of 

tree trunks, apparently in position of original 

growth, and woody fragments and inclusions, which 

suggests rapid burial of a. peat swamp. 

The gray shale seems to be predominantly of nonmarine origin; the shale evidently formed in association with fluvial processes (such as crevasse 

splays and natural levees) and as lacustrine deposits 

of ponded areas that existed relatively briefly before 

complete submergence of the peat swamps. 

Following local deposition of the gray shale and 

limited erosion, possibly by the transgressing seas, 

the first sediment deposited was a black organic-rich 

mud that became a highly fissile, nonplastic carbonaceous shale. The shale commonly contains fish 

remains, inarticulate brachiopods, conodonts, and 

pectinoid pelecypods. The black shale is generally 

not present where the underlying gray shale exceeds 

8 m in thickness. This fact suggests a maximum 

water depth of about 8 m during deposition. 

After deposition of the black mud, a deeper 

marine environment developed. Deposits from that 

environment were generally lighter colored, more 

calcareous sediments that gradually changed to 

marine lime muds as water depth increased, thus 

completing the cycle. Advancement of prodelta mud 

initiated a new but similar cycle of deposition. ·Although many basic similarities can be recognized 

in the different cycles of deposition, no two are 

identical. The recognition of specific differences between individual cycles allows reliable correlation 

.of individual beds over distances of several hundred 

kilometers. 

At the beginning of the Missourian Epoch, the 

east-central part of the United States appears to 

have been more emergent than at any other time 

during the Middle Pennsylvanian (Wanless, 1975, 

p. 88). The Illinois region was subjected to erosion 

by many meandering rivers, whose channels were 

la·ter filled with sand. As many as eight successive 

deltas, which consisted predominantly of mudstone 

and sandstone apparently derived from the northeast or north, were formed during the early part of 

the· Missourian Epoch. No data are available concerning deltaic sedimentation late in Missouri time, 

but as many as six or seven deltas appear to have 

formed. 

Numerous widespread marine transgressions, 

which resulted in the deposition of the thickest 

Pennsylvanian-age marine limestone of I.Ilinois, are 

distinctive of the Missourian Epoch. Wanless ( 1975, 

p. 89) correlated these limestones with thicker 

limestone of the Forest City basin in the northern 

midcontinent region and limestones of the northern 

Appalachian basin, and he believed them to represent eastward transgressions of the sea for at least 

1,600 km. 

Mudstone and sandstone deposits of the Virgilian 

Epoch resemble those of the Missourian Epoch and 

probably represent continued deposition of fluviatile or deltaic channel deposits overlying prodelta 

mudstone (Wanless, 1975, p. 91). At .Ieas~t seven 

marine transgressions, probably from the west, occurred during Virgilian time, but the limestones 
L40 THE MISSISSIPPIAN AND PENNSYLVANIAN SYSTEMS IN THE UNITED STATES 

are commonly thin and are not as extensive as those 

deposited during the Missourian Epoch. 

No record is available of rock strata in Illinois 

that may have been deposited in latest Pennsylvanian or later time, prior to deposition of Upper Cretaceous strata in southern Illinois. A strongly downfaulted graben in western Kentucky opposite Shawneetown, Ill., contains 640 m of rock strata that 

lie above the Shoal Creek Limestone Member 

(Palmer, 1976). The uppermost 460 m of these 

strata are not present in Illinois, and data from 

current studies suggest that the strata, in part, may 

be of Permian age (T. M. Kehn, oral commun., 

1977). Damberger (1971) estimated that the depth 

of burial of the Herrin (No. 6) Coal Member in 

southeastern Illinois may have been 1,370 m or more. 

Because the present maximum thickness of strata 

overlying the No. 6 Goal in Illinois is about 400 m, 

more than 970 m of rock strata may have been 

removed by erosion. 

TECTONIC DEVELOPMENT 

Most major structural features of Illinois originated or had important growth and development 

during •the Pennsylvanian Period. The systematic 

thinning or thickening of strata in the vicinity of 

active structures provides most evidence of growth. 

The buried erosion surface developed upon Mississippian-age strata in the Illinois basin, which was 

mapped by Bristol and Howard (1971), also gives 

evidence of tectonic ac•tivity. 

The La Salle anticlinal belt consists of about 25 

anticlines, synclines, and domes extending from La 

Salle County in northern Illinois to Lawrence 

County in southeastern Illinois, a distance of more 

than 320 km. 

Old Pennsylvanian-age rocks deposited directly 

upon strongly uplifted and beveled late Mississippian strata indicate substantial tectonic movement 

along the La Salle anticlinal belt during the hiatus 

preceding deposition of the Pennsylvanian System. 

Clegg ( 1965) reported progressive movement 

throughout Pennsylvanian time and an interval of 

intensive uplift of all Pennsylvanian strata, that 

took place in either very late Pennsylvanian or postPennsylvanian time. 

Much of the area of the La Salle anticlinal ·belt 

must have been a ·peninsula or archipelago during 

early Pennsylvanian time because no Caseyville-age 

strata were deposited, and the Abbott and Spoon 

Formations are much thinner there than elsewhere 

(fig. 17). The ·Carbondale Formation also shows 

moderate thinning (fig. 18). Relatively thick marine 

limestone of the Modesto and Bond Formations, 

which pass entirely across the anticlinal belt, indicate complete submergence of the area late in 

Pennsylvanian time. The crests of higher anticlinal 

and domed structures were truncated by stream 

erosion and are now covered by Pleistocene glacial 

deposits. 

The Du Quoin monocline and associated Salem 

and Louden anticlines extend along the western 

margin of the Fairfield basin for nearly 160 km. The 

monocline forms a hinge line seperating gently dipping strata to the west from more deeply dipping 

rocks at the western margin of the Fairfield Basin. 

The monocline has local structural relief of about 

150 m at the horizon of the Herrin (No. 6) Coal, 

and more than 300 m in rocks of late Mississippian 

age. 

The Du Quoin monocline did not develop until 

after deposition of youngest Chesterian Series 

strata; maximum growth appears to have occurred 

during early and middle Pennsylvanian time. The 

monocline was active during deposition of both the 

No. 5 and No. 6 Coals and influenced coal thicknesses. The western limit of thick No. 5 Coal generally occurs at the margin of the monocline. The 

eastern boundary of thick No. 6 Coal in southcentral Illinois is along the axes of the Salem and 

Loudon anticlines, which are located on the northern 

extension of the Du Quoin monocline in south-central Illinois. However, in southern Illinois the monocline appears not to have influenced thickness of 

the No. 6 Coal, possibly because no differential 

movement occurred during deposition of the coal. 

Some large structures, such as the Centralia and 

Assumption anticlines, underwent major growth 

and uplift before deposition of Pennsylvanian 

strata, and some continued to grow during the 

Pennsylvanian Period. Others, including the Salem 

and Louden anticlines and deeper structures within 

the Fairfield basin, appear to have completed all 

growth and development after deposition of Pennsylvanian strata. The Illinois basin remained open 

to the south until after deposition of the youngest 

of the Pennsylvanian strata. 

The southern part of the Illinois basin was 

strongly uplifted sometime after deposition of 

youngest Pennsylvanian strata and prior to deposition of oldest Upper Cretaceous rocks. This uplift 

was more than 3,000 m at the crest of the Pascola 

arch, located about 160 km south of the southern 

boundary of Illinois,. and diminished northward. The 

southern margin of Illinois was uplifted about 

760 m. 
ILLINOIS . L41 

The precise age and duration of this uplift is unknown, but may have continued over a long period 

because stratigraphic studies indicate that the Pascola arch was nearly continuously eroded to base 

level during uplift. 

Major compressional thrusting of strata from the 

south or southeast and some concurrent uplift produced the Rough Creek-Shawneetown-Cottage Grove 

fault system and Hicks dome. This deformation occurred during the interval of uplift of the southern 

part of the Illinois basin and may have been associated with the uplift. 

ECONOMIC PRODUCTS 

Coal.-At least 75 coals have been identified in 

the Pennsylvanian System of Illinois. Coals underlie 

about 65 percent of the land area of the State. Resource estimates have been completed for about 25 

coals that are considered to be of minable· thickness 

(.more than 70 em thick), and approximately 20 of 

the coals have been mined commercially. 

A total of nearly 147 billion metric tons of coal 

in the category of identified resources has been determined from mine, drill-hole, and outcrop data. 

These resources constitute the largest deposit of 

identified bituminous coal in any State in the United 

States. 

Approximately 53 million metric tons of coal were 

produced by Illinois mines in 1976, and total production from 1833 to the end of 1976 was about 4.2 

billion metric tons. As of 1977, 60 mines were in 

operation in Illinois, the largest number of which 

are in the southern part of the State. 

Illinois coal extends through the complete range 

of the high volatile bituminous coals. The central 

and northern part of the State is underlain by high 

volatile C bituminous coal. Rank increases progressively southeastward; a small area in southeastern 

Illinois contains high volatile A bituminous coal. Illinois coal generally has a high sulfur content (3 to 

5 percent), although several areas have been identified where coal has a sulfur content of 0.5 to 1.5 

percent. 

Oil.-The first major oil fields in Illinois, discovered at shallow depths in Pennsylvanian rocks 

along the La Salle anticline, were developed between 

1903 and 1913 and resulted in annual production of 

33.1 million barrels ( 4,500,000 metric tons) in 1!no. 

Since these early discoveries, approximately 600 oil 

fields have been discovered in Illinois, and 85, or 

about 14 percent, produce oil from Pennsylvanian 

rooks. Oil has been obtained fro·m 14 productive 

zones in the Modesto, Carbondale, Spoon, Abbott, 

and Caseyville Formations. 

Original oil-in-place in Pennsylvanian rocks is 

estimated to be about 1.6 billion barrels (218,000,-

000 metric tons). Total oil production through 1975 

was about 390 million barrels (53 million metric 

tons). Ultimate recovery of oil from Pennsylvanian 

rocks is estimated to total 431 million barrels (59 

million metric tons) . 

Gas.-Of 82 relatively small gas fields that have 

been discovered in Illinois, 38 have produced gas 

from Pennsylvanian rocks. Two hundred forty-one 

million cubic meters of gas, or about 34 percent 

of estimated total commercial gas production for 

Illinois, has been produced from rocks of the Pennsylvanian System. 

Limestone.-More than 20 limestone beds of the 

Pennsylvanian System, some of which are more than 

8 m thick, underlie much of the State. Thirty-four 

active quarries produced about 8.2 million metric 

tons of limestone from Pennsylvanian rocks in 

1975. Although production of limestone from Pennsylvanian rocks is relatively small, many quarries 

are of considerable economic importance locally, 

because they are in areas where no other sources of 

limestone are readily available. 

Clay .-Clay from Pennsylvanian rocks of Illinois 

has been used for brick manufacture since about 

1818 and for tile, building block, sewer pipe, terra 

cotta, flue liners, stoneware, refractories, bonding 

clays for foundry sands, and lightweight aggregate. 

In 1975, slightly more than 907,000 metric tons 

of clay were produced from the Pennsylvanian System for brick and tile manufacture and for use as 

lightweight aggregate. Buff-burning deposits, which 

are restricted to the Spoon and Abbott Formations, 

yield clay at the northern and western margins of 

the Illinois basin. In the central part, extensive deposits of red-burning clay and shale are essentially 

unlimited sources of common clay. 

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