Devonian of New York

Overview

Modified from the Preface, by Charles A. Ver Straeten

The Devonian Period represents an approximate 60-million-year time span of Earth history (419.0–359.3 million years ago; Becker et al., 2020). It is sometimes termed “The Age of Fishes,” as all major groups of fishes, extant and extinct, existed during this time. Devonian strata are found on all the continents. Some of the key events and processes of theDevonian include: the large-scale colonization of land by Life for the first time, including the first forests, forest ecosystems, and first land vertebrates; several significant global mass extinctions; a shift from greenhouse to icehouse global climate during the Late Devonian; deposition of extensive dark gray to black, organic-rich shale through burial of large volumes of organic-rich material in black shales, decreasing the concentration of CO₂ in Earth’s atmosphere; high sea level and extensive flooding of continental areas; and significant economic deposits, including petroleum and natural gas.

In the 48 years since publication of L. V. Rickard’s (1975) Correlation of the Silurian and Devonian Rocks in New York charts, various high-resolution stratigraphic analyses, employing sequence-, bio-, event-, chemo-, and magnetostratigraphic approaches—sometimes at bed-by-bed scale—along with more refined correlation and geochronologic dating following the discovery of many more airfall volcanic tephras, have led to new understandings of the Devonian succession in the state. All of this permits the authors of this volume to produce a new Devonian stratigraphic synthesis for New York, laid out in a forthcoming time-rock chart that will be published by the Paleontological Research Institution.

Since the mid-nineteenth century, Devonian strata in New York have been considered the North American standard, and remain a key global reference section studied and referred to by geologists worldwide. Based on new GIS data, Devonian rocks are visible at the surface or buried beneath soil and glacial to post-glacial sediment across 40% of New York State (50,535 km² out of a 125,894 km² area; 9,512 mi² out of a 48,608 mi² area).

The first reports of Devonian rocks in New York date back to 1664, and possibly as early as 1627 (Wells, 1963). Subsequent early observations, largely by explorers, general naturalists, and Amos Eaton, the first New York State geologist, eventually led to the establishment of a New York State Geological Survey by the New York State Legislature and Governor William Marcy in 1836 (Aldrich, 2000). Investigations of the New York Devonian, beginning with the first Survey and subsequent work up through the 1960s, led to the publication of two Devonian correlation charts by Dr. Lawrence (Larry) Rickard in 1964 and revised in 1975.

Stratigraphic philosophies applied to sedimentary rock successions by geologists at the New York State Geological Survey/State Museum and other researchers have, at least in part, long differed from those used in some other places. Some stratigraphic units, commonly at group- to formation level, are allostratigraphic/chronostratigraphic/time-rock units (e.g., Cooper, 1930a,b, 1933, 1934). They are in part delineated by biostratigraphic fossil data and distinct marker units, and more recently via high-resolution event correlations and sequence stratigraphic relationships. In many situations, these units cut across facies changes; they are not lithostratigraphic units, where age and time-rock correlation are irrelevant. In addition, other stratigraphic units, such as members, provide lithostratigraphic information.

Rickard’s 1964 and his later 1975 Correlation of the Devonian Rocks in New York charts were very significant resources for Devonian research, from their first publication in the 1960s up to the present. Around the mid-2000s, about 35 years after publication of Rickard’s 1975 chart, the very active group of New York Devonian geologists and paleontologists began discussions on intervals where numerous refinements had been made in the stratigraphy and other aspects which, if published, were scattered in various journals, books, and fieldtrip guidebooks. The discussions also pointed to strata that remained poorly understood and undocumented.

The first significant step toward this new three-volume set and forthcoming chart was a theme session at the 2013 meeting of the Northeastern Section of the Geological Society of America. The session, Refining the Iconic New York Devonian: A New Time-Rock Synthesis, comprised 13 talks and one poster that laid out core elements of most of the chapters in this volume. The intervening years permitted additional fieldwork, analyses, fine tuning, and importantly provided time for more extensive research into two less known intervals, presented in the final two chapters of Volume 3.

Too often, a great amount of knowledge is lost to future workers on the retirement or passing of veteran researchers. Rickard’s 1964 and 1975 charts included only a minor amount of explanatory text. One important, agreed-upon purpose of this volume has been to include extensive detail that is rarely publishable in modern outlets, beyond some fieldtrip guidebooks. To that end, this publication includes extensive, in depth papers that the new, forthcoming correlation chart is based on. In addition, some chapters also present a review of chiefly post-1970 geologic and paleontologic/paleobiologic research, and correlations beyond the state of New York.

Prime examples of such in-depth coverage within this volume are found in chapters tapping the tremendous knowledge of Carlton Brett and Gordon Baird, which they have accumulated over nearly five decades of research each. In this volume, their and others’ knowledge, data, and questions will be available for current as well as future researchers and investigations.

The authors in this volume comprise a group of researchers, most of whose efforts are largely to fully focused on the Devonian strata in New York, and on their implications for the Devonian Period regionally to globally. Of the 20 authors in this volume, seven are serving members of the International Subcommission on Devonian Stratigraphy, an organization within the International Commission on Stratigraphy, comprised of approximately 100 elected members from over 30 countries world-wide.

The aims of this volume are fivefold: 1) to update the Rickard (1975) Correlation of the Silurian and Devonian Rocks in New York; 2) to provide detailed explanations and formal proposals of post-1975 stratigraphic changes, absent in Rickard’s 1964 and 1975 correlation charts; 3) to preserve detailed knowledge about units not generally published, especially in the case of the authors with more extensive careers; 4) in some chapters, to present reviews of other geological and paleontological aspects of the strata, chiefly focused on post-1970/post-Rickard (1975) research; and 5) in some chapters, to present correlations of strata beyond the boundaries of New York State.

The three volumes of Devonian of New York consists of twelve chapters. Following this brief Preface and a Dedication to Lawrence (Larry) V. Rickard (Ver Straeten, 2023a [Vol. 1, Dedication]), Chapter 1 of the first volume of Devonian of New York examines the hybrid stratigraphic philosophy and practice that has long been applied to Devonian strata in New York. This is followed by overviews of the Devonian Period, of the Devonian in North America/Laurentia, and a history of Devonian research in New York State, concluding with a stage-by-stage overview of the succession (Ver Straeten, 2023b [Vol. 1, Ch. 1]).

Chapter 2 of Volume 1 presents a different view of the lower Lower Devonian Lochkovian Stage Helderberg Group in the state, sharply contrasting with the long-standing Rickard model (Ebert and Matteson, 2023 [Vol. 1, Ch. 2]). Chapter 3 then examines middle to upper Lower Devonian strata of the Pragian and Emsian stages, including the Oriskany, Esopus, and Schoharie formations in New York State, and their correlative strata along the Appalachian Basin outcrop belt (Ver Straeten, 2023c [Vol. 1, Ch. 3]). Chapter 4 continues upward into the lower Middle Devonian, of the Eifelian Stage Onondaga Limestone and the Eifelian and lower Givetian Stage Marcellus subgroup, as defined in New York State. The chapter also presents correlation of these strata circumbasinally around the Appalachian Basin outcrop belt (Ver Straeten et al., 2023 [Vol. 1, Ch. 4]).

Volume 2 of Devonian of New York continues through the Middle Devonian in three chapters. The first chapter examines the middle to upper Hamilton Group (Givetian Stage) across central to western New York. These strata comprise one of the most detailed successions in the Devonian, with shell bed to shell bed correlation across broad stretches of the state. These strata have, and continue to provide, a highly proven field lab for testing various geological and paleontological questions, such as sequence stratigraphic models, and Punctuated Equilibrium in evolution (Brett et al., 2023 [Vol. 2, Ch. 1]). Chapter 2 examines much less known marine Hamilton strata in eastern New York, presents old and new data and correlations, and outlines pathways for further research (Bartholomew and Ver Straeten, 2023 [Vol. 2, Ch. 2]). Finally, in this volume, Baird et al., 2023a [Vol. 2, Ch. 3]) present a new synthesis of the Tully and Geneseo formations and correlatives, up to the Middle-Upper Devonian boundary.

Volume 3 of the Devonian of New York examines various aspects of the Upper Devonian marine strata of the Frasnian and Famennian stages in New York State. In Chapter 1, Over et al. (2023 [Vol. 3, Ch. 1]) lay out current understandings of Frasnian stratigraphy in western and central New York, with details of the bio- and sequence stratigraphy. Chapter 2 (Bush et al., 2023 [Vol. 3, Ch. 2]) outline new correlations between shallow- and-deep water facies proximal to the Frasnian-Famennian boundary. In Chapter 3 Smith and Jacobi (2023 [Vol. 3, Ch. 3]) examine the complexities of intra-and extrabasinal processes on chiefly Famennian-age strata in western New York. Chapter 4 of Volume 3 examines the uppermost Devonian strata and global events in western New York that includes strata in northwestern Pennsylvania and northern Ohio to reach the Devonian-Carboniferous boundary in the northern Appalachian Basin (Baird et al., 2023b [Vol. 3, Ch. 4]). Volume 3 concludes with a chapter on the Devonian terrestrial system in New York, with overviews of various aspects of the geology, paleobiology, and the state of knowledge of the largest remaining frontier of the Devonian in New York and across the eastern United States (Ver Straeten, 2023d [Vol. 3, Ch. 5]).

Rickard’s 1964 and 1975 charts provided an overall structure of the New York Devonian to guide the explorations and extensions of many geologists and paleontologists. We hope this volume leaves a trove of knowledge, questions, and goals to stimulate future research and researchers in New York and beyond.

There are many people to thank for assisting with the forthcoming revision of Rickard’s (1975) Correlation of the Devonian Rocks in New York, and the accompanying text in these three volumes. The authors and co-editors all deeply thank the Paleontological Research Institution (PRI) for publishing this voluminous collection and for taking on technical editing, most notably PRI Director Warren Allmon, PRI’s Editor-In-Chief of Bulletins of American Paleontology, Jonathan Hendricks, and Associate Editor Elizabeth Hermsen. We also deeply thank the numerous collaborators, mentors, discussion partners, students, assistants, and other researchers who have lent their efforts and knowledge to building this new synthesis. Additional thank yous to those researchers who constructed the stratigraphic and other geologic and paleontologic foundations upon which we build, beginning in the mid 18th to early 19th centuries and continuing even to today. And to various organizations who funded various aspects of the new research over the many decades. Finally, the lead editors of this volume, Chuck Ver Straeten, Jeff Over, and Don Woodrow, express their deep gratitude to the authors, associate editors Diana Boyer, Amanda Colosimo, and Jim Ebert, and to the reviewers who generously gave their expertise and time to improving this volume, with an added thank you to those who reviewed the longer chapters. They include two anonymous reviewers, Thomas Becker, Thomas Berg, Diana Boyer, Rainer Brocke, Andrew Bush, James Ebert, Nancy Hasenmueller, Philip Heckel, Jon Inners, Gerald Kloc, Richard Lindemann (three reviews), George MacIntosh, Patrick McLaughlin, Anne Raymond, Rudy Slingerland, Michael Trippi, Jeffrey Trop, and Michael Whalen. Finally, a bow of great appreciation to Lawrence (Larry) Vroman Rickard, whose efforts inspired 48 years of research since publication of his 1975 chart, Correlation of the Devonian Rocks in New York.

Preface

by Charles A. Ver Straeten. Pp. 1–5, DOI: 10.32857/bap.2023.403.01.

Dedication: To Dr. Lawrence (Larry) V. Rickard

by Charles A. Ver Straeten. Pp. 7–10, DOI: 10.32857/bap.2023.403.02.

Chapter 1: An introduction to the Devonian Period and the Devonian in New York State and North America

by Charles A. Ver Straeten. Pp. 11–102, DOI: 10.32857/bap.2023.403.03.

Abstract. The Devonian strata in New York State were the standard section for North America for over 100 years, and remain a significant reference for regional to global correlation and research. Since publication of L. V. Rickard’s (1975) New York Devonian correlation chart, various higher-resolution stratigraphic analyses have been employed, sometimes at bed-by-bed scale. These include sequence-, bio-, event-, chemo-, and other -stratigraphic approaches, along with increasingly finer-resolution geochronologic dating of airfall volcanic tephras. Results have led to many new interpretations and insights of the succession. The purpose of this three-volume work is to produce a new Devonian stratigraphic synthesis for New York State, and to record, often in detail, current knowledge of the succession, and various other geologic and paleontologic aspects of it for current and future research and discussion. The purpose of this chapter is to provide overviews of the Devonian Period, the Devonian of North America (“Laurentia”), the Devonian of eastern Laurentia, and the Devonian of New York State. Furthermore, this review extends beyond the sedimentary rock and paleobiological record, and beyond the United States, Canada, and northern Mexico, to also summarize aspects of Devonian orogenesis, metasedimentary foreland basin fill, silicic igneous activity, complexities of terranes of Mexico and Central America, and Appalachian faunas that extended into South America.

The Devonian Period as a whole encompasses 60 million years of time, approximately 419 to 359 million years ago. During that time, shallow seas covered large continental areas; climate was warmer globally than our current climate, during the late stage of a global greenhouse climate. By the end of the Devonian, that warm climate was descending into a time of global icehouse conditions, with widespread glaciation. The positions of modern continental masses were much different. During the Devonian Period, Life first fully colonized the land, led by primitive spore-bearing plants, small arthropods, and apparently by the Middle Devonian, the first tetrapod (“four-legged”) animals, which evolved from bony fishes. Decimeter-tall plants at the beginning of the period had evolved to tree-size forms by the Middle Devonian, approximately 30 million years later, and Earth’s first forest ecosystems arose.

Devonian strata are widespread around the ancient continent “Laurentia,” which approximately corresponds to modern North America). At that time, Laurentia straddled the equator, with New York State and the Appalachian region somewhat north of 30° south latitude. Shallow epicontinental seas covered large but varying amounts of the continent over the period. Mountain belts formed on the eastern, northern, and western margins of Laurentia, due to plate tectonic collisions with smaller continental masses, exotic terranes, and volcanic island arcs. Through the Early to Middle Devonian, seas in western and eastern Laurentia were separated by a “transcontinental arch,” and generally had distinctly different marine faunas. In the latest Middle Devonian, sea level transgressed over the land barrier of the Laurentian Transcontinental Arch and the Canadian Shield, and those marine faunas mixed, leading to a more global cosmopolitan fauna in the Late Devonian. Anomalously, however, Early and Middle Devonian Laurentian shallow marine faunas are found in Devonian rocks in Central and South America, which were part of the southern Gondwana continent, generally thought to be separated from Laurentia by oceanic water depths at that time.

During the Devonian, eastern Laurentia was an active tectonic margin, related to continent-continent collisions with various terranes/smaller continental masses. The Caledonian, Acadian, and Neoacadian orogenies resulted in compressional and some transpressional tectonics, and the uplift of an extensive mountain belt from east Greenland to Alabama and Georgia. Crustal loading of the orogen in eastern Laurentia led to subsidence and formation of a retroarc Acadian-Neoacadian Foreland Basin, which was initially filled with marine waters, followed by gradual overfilling to above sea level by massive volumes of synorogenic sediments from the east. The resulting lands were the site of some of the earliest forests on Earth, preserved at several sites in New York State, and forest ecosystems. Large-scale deformation, seismic activity, and metamorphism in the mountain belt were accompanied by igneous processes, including explosive eruption of felsic volcanic ash and other material, collectively termed “tephra,” also sometimes termed ash or tuff layers, or if diagenetically altered, sometimes termed bentonite, K-bentonite, metabentonite, or tonstein layers. These explosive Devonian eruptions sent volcanic tephra high into the atmosphere, and easterly winds spread airfall volcanic “tephra layers” across the eastern United States. Meanwhile, rock decay in the mountains led to the erosion, transport, and deposition of massive volumes of clays, silt, sand, and gravel into the Acadian-Neoacadian Foreland Basin, and beyond.

Devonian rocks in New York are found at or just below the surface across approximately 40% of the state (~50,500 km²/19,500 mi²). The strata are generally undeformed and gently dipping, and while often covered by soil, glacial sediments, and vegetative cover, are relatively widely found in natural and man-made exposures. Three relatively thin intervals of carbonates are accompanied by eastward thickening wedges of synorogenic mudrocks, sandstones, and minor conglomerates. The history of geological and paleontological observation and study in New York began in the late 18th century. The first professional geologists appeared in the early 19th century. Since the advent of the first geological survey of New York State in 1836, the Devonian Period (nearly termed the “Erian Period” for New York’s Devonian-age rocks) has been the focus of a great volume of research which continues today.

The Devonian succession in New York includes strata from all seven stages of the period, with erosional gaps of small to major significance. In addition to a range of marine facies, nearly one quarter of the entire area of Devonian bedrock in the state was deposited in terrestrial settings, with massive volumes of siliciclastic sediments shed off of Acadian-Neoacadian highlands to the east, that also feature the fossils of Earth’s oldest known forest ecosystems. The stratigraphic philosophy in New York has long evolved toward a hybrid classification, wherein groups, formations, and bed-level units are largely time-rock/allostratigraphic to occasionally chronostratigraphic, with lithostratigraphy often ascribed to member-level divisions (e.g., Pragian to Givetian strata, middle Lower to upper Middle Devonian). However, in some intervals, such as Frasnian strata (lower Upper Devonian), group-level units are time-rock units, and formation-level units within groups are largely lithostratigraphic.

Forty-eight years of research since Rickard’s (1975) New York Devonian correlation chart permits development of a new, more refined chart (forthcoming), and also permits a new synthesis of Devonian rocks and fossils in New York, presented in this work of twelve chapters, with additional digital appendices.

Chapter 2: Lithostratigraphy, multi-taxa biostratigraphy, and sequence stratigraphy of the Helderberg Group (Přídolí–Lochkovian) in New York State

by James R. Ebert and Damon K. Matteson. Pp. 103–151 (including 1 plate), DOI: 10.32857/bap.2023.403.04.

Abstract. Historically, the Helderberg Group has been an important unit including some of the earliest paleontologic and stratigraphic studies in North America. Once interpreted as a series of coeval facies, most formations and even some members of the Helderberg Group are separated by disconformities and regionally angular unconformities. The Green Vedder Member (new) is defined within the Manlius Formation and the Dayville Member is reassigned from the Coeymans to the Manlius Formation. The name Ravena member of the Coeymans Formation is abandoned because it coincides entirely with the redefined Coeymans Formation. Two new members, Jefferson Heights and Leeds Gorge, are recognized within the New Scotland Formation. A cluster of tephra beds occurs in the Kalkberg Formation, the upper Jefferson Heights and lower Leeds Gorge members of the New Scotland Formation. Strata formerly described as an “upper tongue of the Kalkberg Formation” are referred to as the Old Stone Fort Member (new) of the Becraft Formation. The Deansboro, formerly a member of the Coeymans Formation, is raised to formational rank owing to its physical and biostratigraphic separation from the Coeymans Formation. Reef-bearing strata may still comprise a part of the Deansboro Formation or may be removed and referred to as the Mosquito Point Formation (new). Strata that overlie the Deansboro Formation in central New York that had been regarded as part of the Kalkberg Formation differ lithologically and are significantly younger than the Kalkberg. They are therefore redefined as the Buckley Mill Formation (new).

Major unconformities occur between the Chrysler Member of the Rondout Formation and the Thacher Member of the Manlius Formation (Mine Lot Falls Unconformity), between the Thacher and Green Vedder members of the Manlius Formation (Clockville Unconformity), and between the Green Vedder Member and the Olney and Dayville members (Terrace Mountain Unconformity). The Columbia Center Unconformity separates the Olney from the overlying Dayville Member. The Howe Cave Unconformity marks the base of the Coeymans Formation and is basin-wide in its extent. The Punch Kill Unconformity caps the Coeymans Formation and is onlapped by four subunits of the Kalkberg Formation. The Getman Corners Unconformity marks the base of the Deansboro Formation and erosionally separates this unit from the Helderberg Group.

The Silurian–Devonian boundary interval (base of the Lochkovian Stage) occurs in the upper portion of the Green Vedder Member of the Manlius Formation. The co-occurrence of scyphocrinitid loboliths and a positive δ¹³C excursion (Klonk Event) in facies that represent deeper, dysoxic conditions characterize the boundary interval. The Judds Falls Bentonite Bed is constrained to the middle Lochkovian (upper bohemica Zone) by a somewhat diverse chitinozoan fauna. A mid- to late Lochkovian age for the Becraft and Alsen formations is indicated by chitinozoans. Additional chitinozoan data suggest that the Lochkovian–Pragian boundary occurs in the Port Ewen Formation. Pragian conodonts from the Deansboro Formation mark a maximum age for the bioherms that have been grouped with the Deansboro. A Pragian age is also likely for the Buckley Mill Formation that overlies the Deansboro Formation, but chitinozoan studies from this unit are not yet completed. Seven epiboles of various crinoids and cystoids are recognized and are important marker horizons in the revised stratigraphy.

The sequence stratigraphic framework of the Helderberg Group suggests that the stratigraphic architecture is strongly controlled by episodic, tectonically-driven subsidence produced by crustal loading during a pre-Tectophase I episode of Acadian orogenesis. During deposition of the Thacher Member of the Manlius Formation, maximum subsidence occurred in the region around Cherry Valley, New York. During deposition of the overlying Green Vedder Member, a low arch developed in this region, separating two sub-basins. The Cherry Valley Arch disappeared during deposition of the Dayville Member of the Manlius Formation and maximum subsidence was centered near Columbia Center, New York. The Cherry Valley Arch was reactivated and broadened to extend between Cherry Valley and the area around West Berne during deposition of the Elmwood through Jamesville members of the Manlius Formation. The Cherry Valley Arch disappeared as subsidence increased during deposition of overlying Helderberg units. Post-Manlius formations document eastward migration of the axis of maximum subsidence and bathymetric axis of the basin through time. This pattern reversed during deposition of the lower part of the Becraft Formation in which deeper water facies (Old Stone Fort Member) were deposited in the Schoharie region and shallower environments developed in the Hudson Valley. This transposition was short-lived as maximum subsidence migrated into the Hudson Valley region once again and persisted during deposition of the upper Becraft and the overlying Alsen and Port Ewen formations. The newly developed sequence stratigraphy and biostratigraphy in the Appalachian Standard Succession (New York State) enable revised correlations within the Central Appalachian Basin.

Chapter 3: The Port Jervis, Oriskany, Esopus, and Schoharie formations, and equivalents: Pragian and Emsian strata of New York

by Charles A. Ver Straeten. Pp. 153–204, DOI: 10.32857/bap.2023.403.05.

Abstract. Middle to upper Lower Devonian strata in New York are comprised of seven formations, in four distinct vertical packages. They were deposited over an interval of approximately 18.2 million years. The lowest strata (lower Pragian-age Port Jervis Limestone) occur only in the Tristates area, southeastern New York. Overlying upper Pragian-age units are the largely co-eval Oriskany Sandstone, Glenerie Cherty Limestone, and Connelly Conglomerate. Overlying synorogenic siliciclastics of the Esopus Formation (lower Emsian-age) are restricted to eastern to east-central New York. Overlying upper Emsian strata of the correlative Schoharie and Bois Blanc formations comprise mixed siliciclastic-carbonate and carbonate strata, respectively, with some quartz arenites, especially across central New York. These New York units, and their correlatives across the Appalachian Basin outcrop belt, areexamined and summarized.

In nearly all of New York, some to all of these strata are absent at an erosional unconformity. The Tristates area at the meeting of New York, New Jersey, and Pennsylvania is the only area of the outcrop belt where deposition was continuous through this time. To the overall north and west, a major Paleozoic sea level lowstand Å} crustal flexure during the Acadian orogeny led to development of an amalgamated series of unconformities, focused around the sub-Oriskany Wallbridge Unconformity. Maximum development of the unconformity in New York occurs in the west-central part of the state. In terms of sequence stratigraphy, the entire succession comprises six or seven major, third-order sequences. This includes two likely Pragian sequences, and five distinct Emsian-age sequences, all of which appear to be global. A series of altered airfall volcanic tephras occur in the lower part of the Esopus Formation; a few additional discrete airfall tephras are known from the Schoharie Formation. Faunal differences distinguish the four vertical packages of strata. Too little biostratigraphic data, however, continues to limit the accuracy of pinpointing stage boundaries in the New York and Appalachian Basin strata.

Chapter 4: Lower Middle Devonian (Eifelian–lower Givetian) strata of New York State: The Onondaga Formation and Marcellus Subgroup

by Charles A. Ver Straeten, Carlton E. Brett, Gordon C. Baird, Alexander J. Bartholomew, and D. Jeffrey Over. Pp. 205–280, DOI: 10.32857/bap.2023.403.06.

Abstract. Lower Middle Devonian strata (Eifelian to lower Givetian stages) of New York are identified under the names Onondaga and Marcellus. As has been New York practice for over 80 years, they represent time-significant allostratigraphic units, which to some degree cut across lithologic boundaries. The Onondaga Formation is a relatively tabular, limestone-dominated unit throughout New York. Strata thin from both east and west into more basinward facies in the central part of the state. In contrast, the (revised) “Marcellus subgroup” forms an eastward-thickening and coarsening wedge of siliciclastic-dominated facies. Marcellus-equivalent strata range in thickness from less than seven meters in the western New York subsurface to an estimated maximum thickness of 580 meters in the Hudson Valley, eastern New York.

Few stratigraphic revisions have been proposed for the Onondaga Formation since 1975, beyond minor revisions to two members associated with the abandonment of the informal, former Clarence member, chert-rich facies in western New York. In contrast, the term “Marcellus” has been raised in New York State from formation to subgroup status, with three formation-level units: a lower Union Springs and coeval upper Marcellus Oatka Creek and Mount Marion formations. The latter two represent correlative basinal dark shales and proximal dark shales to shoreface sandstones, respectively. Overall, following Cooper’s classic 1930s stratigraphy of one formation with 11 members, 13 members are now recognized in the Marcellus subgroup; two in the Union Springs Formation and 11 in the upper Marcellus Oatka Creek and Mount Marion succession.

Onondaga and Marcellus strata form three third-order depositional sequences, which feature three very distinct faunas. The sequences, termed Devonian Sequences Ic, Id, and Ie (alternatively Eif-1, Eif-2, and Eif-Giv) consist, respectively of 1) lower to middle Onondaga; 2) upper Onondaga and Union Springs; and 3) coeval Oatka Creek and Mount Marion formations, except where upper Mount Marion strata are not yet clearly distinguished form lower Skaneateles equivalents in eastern New York. The fossil assemblages of the Eifelian to lower Givetian have been subdivided into three “faunas” or ecological-evolutionary subunits. The oldest of the three faunas, the Onondaga Fauna, is succeeded by the Stony Hollow Fauna in shallow facies of the upper Union Springs and lowermost Mount Marion-Oatka Creek formations. The Stony Hollow Fauna is, in turn, succeeded by the classic Middle Devonian Hamilton Fauna throughout the remainder of upper Marcellus strata and Hamilton strata above.

Numerous post-1970 studies have examined the stratigraphy, petrology, sedimentology, basin analyses, paleobiology, and geochemical characters of the Onondaga Formation and Marcellus subgroup. Overviews of these studies are presented herein. In the Appalachian Basin, the correlatives of these units across have been assigned the same names, Onondaga and Marcellus, in eastern Pennsylvania. More argillaceous Onondaga-correlative strata form the upper part of the Needmore Formation from central Pennsylvania to the vicinity of Highland and Pocahontas counties, in Virginia and West Virginia, respectively (Selinsgrove to the informal “calcareous shale and limestone” members). Continuing southwest along the Virginia-West Virginia border, Onondagacorrelative strata are replaced by chert and shale-dominated strata in the upper part of the Huntersville Formation.

South of New York in the Appalachian Basin, the term “Marcellus” is applied lithostratigraphically, not allostratigraphically, so that lowest strata assigned the term Marcellus may variously range from lower Eifelian (middle Onondaga-equivalent, e.g., Frankstown, Pennsylvania) to correlative with the base of the Marcellus in New York. Similarly, youngest strata assigned to the Marcellus in Pennsylvania and southward may range from upper Eifelian Union Springs-equivalent (below proximal sandstones of the Turkey Ridge Member, central Pennsylvania) to lower Givetian, post-Marcellus black shales correlative with at least the Skaneateles Formation of New York in distal, basinward areas. From Highland County, Virginia, and adjacent West Virginia to the southwest, Marcellus strata are assigned to the lower part of the Millboro Shale, Finally, in southwestern Virginia and adjacent West Virginia, strata termed Marcellus in New York occur in lower parts of an interval sometimes termed “New Albany Shale” but shown by their correlation to be equivalent to upper Onondaga or lower Marcellus strata, based upon airfall volcanic tephras.

Chapter 1: Stratigraphy and facies of the middle and upper Hamilton Group (Middle Devonian; Givetian) in New York State and adjacent areas

by Carlton E. Brett, Gordon C. Baird, James J. Zambito IV, and Alexander J. Bartholomew. Pp. 1–195, DOI: 10.32857/bap.2023.405.01.

Abstract. The Middle Devonian (lower–middle Givetian) Hamilton Group of New York State is an iconic unit in North America, which has contributed many key concepts in stratigraphy, sedimentary geology, paleoecology, and evolution. This interval comprises a 100- to 1200-m-thick clastic wedge, shed westward from the Acadian Mountains, with thin but persistent carbonates. Despite the rich and diverse invertebrate fauna that consists of more than 300 species of corals, bryozoans, brachiopods, mollusks, echinoderms, and trilobites, the age of the Hamilton Group is rather poorly constrained in terms of chronostratigraphy owing to the rarity of biostratigraphically useful conodonts and goniatites. The upper part of the Hamilton Group that is the focus of this paper apparently belongs to the Polygnathus timorensis to middle Polygnathus ansatus Conodont chronozones. The middle to upper Hamilton Group in New York State comprises three formations—the Skaneateles, Ludlowville, and Moscow—each defined as an interval delimited with a sharply based fossiliferous limestone-calcareous siltstone; these formations are interpreted as containing condensed transgressive deposits overlain by thicker highstand to falling-stage shales, mudstones/siltstones, and sandstones. The eastern equivalents of these formations are dominated by fine-grained sandstones and siltstones and include two formations: the Panther Mountain Formation, equivalent to the Skaneateles and Ludlowville formations combined, and the Cooperstown Formation, equivalent to the Moscow Formation. In the present paper, we review, revise and update a hierarchical framework of lithostratigraphic subdivisions of these formations, including 24 members (four new), 50 submembers (more than half newly proposed or redefined; 14 informal at this time), and more than 80 named beds, both formal and informal. This refined lithostratigraphy provides an excellent framework for studying high-resolution sequence stratigraphy. As defined herein, members and most submembers represent high-frequency depositional sequences with basal shell-rich carbonates and abrupt flooding surfaces that mark the bases of highstand deposits. Not only are most of the members and submembers traceable across western and central New York, but also to a lesser extent into adjacent regions that include southern Ontario, Ohio, the Michigan Basin, and northeastern Pennsylvania. Nevertheless, much work on correlation remains to be done in eastern New York and central Pennsylvania, where local progradation of siliciclastics and expansion of successions obscures many of the finer scale features.

Chapter 2: Marine strata of the middle to upper Hamilton Group (Middle Devonian, lower Givetian), eastern outcrop belt in New York State

by Alexander Bartholomew and Charles A. Ver Straeten. Pp. 197–258, DOI: 10.32857/bap.2023.405.02.

Marine strata of the Middle Devonian Hamilton Group in eastern New York State consist of a thick succession of synorogenic basinal to shoreface sediments. Initial basinal dark to black shales grade upward through increasingly coarse, sand-dominated facies. Beginning in Marcellus (early Givetian-age) strata in the Hudson Valley, these marine facies grade upward and laterally into terrestrial strata. This major transition occurs diachronously with higher strata undergoing transition to terrestrial facies progressively further westward. Time-rock/allostratigraphic relationships in these rocks have long remained poorly understood. This chapter examines older and recent observations and presents new interpretations and hypotheses on the correlation of these strata. The purposes of this work are to: 1) better constrain the position of the marine to terrestrial transition in upper the Marcellus subgroup strata; 2) better constrain the contact “interval” of the marine Mount Marion-Panther Mountain formations; 3) present current knowledge and hypotheses about the Panther Mountain Formation; 4) discuss the presence of two intervals of unique fauna, each consisting of an epibole of the brachiopod Schizophoria King, 1850 in southern Albany County and northeastern Greene County together with correlation of these intervals southward into Ulster County; 5) discuss basal strata of the upper Hamilton Cooperstown Formation through Schoharie to Greene counties; and finally, 6) present an overview of development of the Hamilton Group between Kingston, Ulster County and Port Jervis, Orange County, where New York, New Jersey, and Pennsylvania meet. Methods utilized include reviews of older reports, new findings, sequence stratigraphy, correlation of distinct marker units, some faunal assessment (e.g., Schizophoria fauna intervals and other faunal associations, including a coral-rich bed), and some lithologic indicators of relative depths (e.g., thin, decimeter-scale conglomerates). The synthesis and resulting interpretations presented in this chapter are more tentative than in some chapters; however, the authors attempt herein to lay the groundwork for future research.

Chapter 3: Tully Formation and pre-Frasnian Genesee Group succession

by Gordon C. Baird, James J. Zambito IV, and Carlton E. Brett. Pp. 259–378, DOI: 10.32857/bap.2023.405.03.

Abstract. Strata between the middle Givetian Moscow Formation and the newly recognized Givetian-Frasnian zonal stage boundary, at or near the top of the Lodi Member (Penn Yan Formation of the Genesee Group), include limestone-dominated strata of the Tully Formation and coeval siliciclastic deposits of the Gilboa Formation, overlain by progradational, siliciclastic deposits of the Geneseo Formation-Lodi Member succession. The Tully and Gilboa formations, the type expression of the North American provincial Taghanic Stage, correspond to the Polygnathus ansatus–“Ozarkodina” semialternans international conodont zones, and the Global Taghanic Biocrisis interval. The lower, pre-Frasnian part of the Genesee Group, corresponding to the successive hermanni (former hermanni-cristatus Zone), disparilis, and norrisi conodont zones, recorded the onset of a major Acadian tectophase (Tectophase 4; see Ver Straeten, 2023a [Vol. 1, Ch. 1]), timed with coincident deepening of the Devonian foreland basin and major global sea level-rise.

The Tully Formation limestone in western and central New York State is an anomalous deposit of dominantly fine grained, medium to dark gray limestone that contrasts greatly with underlying Hamilton Group siliciclastic deposits and overlying progradational siliciclastic facies of the Genesee Group. Tully Formation deposits in western and central New York accumulated on a shallow platform. However, these deposits grade eastward and southward into the equivalent thicker siliciclastic Gilboa Formation, preserved within a structural trough or, possibly, a small-scale orogen-ward migrating basin, in eastern New York and central Pennsylvania that served as a “clastic trap” for siliciclastic sediments which failed to reach the platform. Diachronous basal Geneseo deposits record the westward regional onlap of basinal black mud deposits onto an east-sloping submarine ramp. The Geneseo Formation recorded geologically rapid subsidence and development of a shelf-slope break that imparted a strong control on sedimentary magnafacies.

The Tully Formation largely displays distinctly clean carbonate deposits in central New York; the Gilboa Formation is herein applied to coeval eastern (shoreward) siliciclastic facies. Post-Gilboa, Geneseo-equivalent onshore divisions, which include the Unadilla Formation, Sherburne Formation, Otego Formation, and Otselic Formation, are, herein, delineated. Most member-scale units of the Tully- and Geneseo-correlative formations, described herein, correspond to divisions based on discontinuity-floored marine sequence and subsequence concepts.

Chapter 1: The Frasnian strata—lower Upper Devonian—of New York State

by D. Jeffrey Over, Gordon C. Baird, and William T. Kirchgasser. Pp. 1–28, DOI: 10.32857/bap.2023.407.01.

Abstract. Frasnian strata of New York are within the Genesee (in part), Sonyea, West Falls, and Java (in part) groups, consisting of strata that grade from terrestrial clastics in the east to offshore dark-colored shale and pelagic limestone in the west. These strata contain tephra beds, brachiopods, conodonts, goniatites, spores, and other flora and fauna that allow global correlation and recognition of zonal and stage boundaries. Five third-order cyclic packages are recognized by distinct black shale to gray shale groups that are recognized within corresponding strata of the Burket and Harrell shale formations in Pennsylvania, the Flynn Creek and Dowelltown members of the Chattanooga Shale Formation in the southern Appalachian Basin, the Blocher and Selmier members of the New Albany Shale Formation in the Illinois Basin, and the Squaw Bay Limestone Formation and Norwood and Paxton members of the Antrim Shale Formation in the Michigan Basin.

Chapter 2: Stratigraphy of the Frasnian-Famennian boundary interval in shallow-marine paleoenvironments of New York and north-central Pennsylvania (Wicoy–Caneadea formations, Upper Devonian)

by Andrew M. Bush, J. Andrew Beard, Sarah K. Brisson, Jaleigh Q. Pier, and Michael T. Hren. Pp. 29–46, DOI: 10.32857/bap.2023.407.02.

Abstract. The Frasnian-Famennian boundary interval is exposed in New York State in an outcrop belt that stretches from Lake Erie eastward to Steuben County, continuing into Pennsylvania. Recent biostratigraphic examination of brachiopods and conodonts suggested that the shallower water sections to the east have been miscorrelated with the deeper water sections to the west. Revised correlations place the Upper Kellwasser extinction event (Frasnian-Famennian boundary) within the Canaseraga Formation and the Lower Kellwasser extinction event (Pipe Creek Formation) above the Wiscoy Formation. We review these revised correlations and provide additional support based on δ¹³Corg profiles from several sections. We also define new members in the Wiscoy Formation (Rossburg Member) and Canaseraga Formation (Hornell, Elkhorn Creek, and Crooked members) that should facilitate discussions of faunal and paleoenvironmental changes associated with the Frasnian-Famennian extinctions in the Appalachian Basin.

Chapter 3: Upper Frasnian and Famennian stratigraphy in western New York State

by Gerald J. Smith and Robert D. Jacobi. Pp. 47–111, DOI: 10.32857/bap.2023.407.03.

Abstract. The upper Frasnian and Famennian Devonian stratigraphy in central and western New York State is comprised of the upper Frasnian West Falls and Java groups and the Famennian Canadaway, Conneaut, and Conewango groups. The Devonian stratigraphic correlation chart compiled by Rickard (1975) has been the general standard for the Frasnian and Famennian section in central and western New York. However, Rickard’s (1975) chart predates sequence stratigraphy, more sophisticated biostratigraphic and δ13Corg studies, and the recognition of numerous faults that offset the “layer-cake” stratigraphy. Our detailed field studies at over 2,000 sites that involved sedimentology, sequence stratigraphy, structure, and ichnology promoted the identification and tracing of key marker beds in central and western New York State. These studies encouraged a revision and refinement of the units and correlations that were represented in the Rickard (1975) stratigraphic chart. Revisions to Rickard’s (1975) Devonian stratigraphic chart include: abandoning the Perrysburg and Forty Bridge formations; reinstating units that Rickard (1975) omitted in his compilation, including the South Wales, Canaseraga, Rushford, Machias and Cuba formations, as well as theSalamanca Member; and proposing new East Sixtown, Gorge Dolomitic, Higgins, and West Lake members of the Caneadea Formation. We revised seven other units; fifteen units remain unchanged. A consequence of this new stratigraphy is a more robust depositional history for the Upper Devonian in central and western New York State. The Upper Devonian stratigraphic units of New York State record the transition from deeper-water shales and turbidite sandstones to terrestrial sands and shales as the Acadian Foreland Basin filled and the shoreline moved farther westward through time. The westward march of the shoreline was not steady, however, and was controlled by the usual interplay of 1) basin subsidence and fault block motion, 2) sediment supply, and 3) eustatic variation. The last of the Devonian black shale deposition occurred in the Frasnian/Famennian. The Frasnian is typified by offshore deposition, including turbidities. In contrast, the sedimentary structures and ichnofacies observed indicate the Famennian stratigraphy represented a shallower, offshore-to-nearshore depositional environment. The occurrence of storm influenced/modified bedding becomes ubiquitous in units of the upper Canadaway, Conneaut, and Conewango groups. Exposures of the Conneaut and Conewango typically are comprised of the thicker, fine sandstone packets. Fewer outcrops upsection result in less definitive correlations. Correlations in the Conneaut and Conewango are dependent on the presence of marker beds that contain distinctive lithologies such as red shales and beds containing white quartz pebbles.

Chapter 4: Late Famennian Conneaut Group to basal-Mississippian stratigraphic succession and geochronology, New York/Pennsylvania borderland and Lake Erie region

by Gordon C. Baird, John A. Harper, D. Jeffrey Over, Joseph T. Hannibal, Scott C. McKenzie, and Irving H. Tesmer. Pp. 113–209, DOI: 10.32857/bap.2023.407.04.

Abstract. Upper Famennian strata, including a time slice from the international Palmatolepis marginifera conodont Zone to the Protognathodus kockeli conodont Zone, and part of the Cheiloceras ammonoid Zone, upward to the topmost Acutimitoceras ammonoid Zone at the Devonian-Carboniferous boundary, are well exposed in the southern part of the western New York Southern Tier region and in adjacent Pennsylvania and northern Ohio. This interval includes offshore marine to paralic deposits in the Conneaut and Conewango groups in New York and correlative Chadakoin and Venango formations in northwest Pennsylvania, as well as strata comprising parts of the Chagrin Member of the Ohio Shale in Ohio. Terrestrial deposits, time-equivalent to the Conneaut and Conewango groups, are represented by the Catskill Formation in north-central Pennsylvania.

Offshore marine-to-paralic units in the post-Conewango Group–pre-Cuyahoga Group time slice are exposed mainly in northwest Pennsylvania and northern Ohio. In Ohio, they include, in ascending order, the Cleveland Member of the Ohio Shale, the Bedford Shale, and the Berea Sandstone. In northwest Pennsylvania they include the “Drake Well Formation,” Knapp Formation, Corry Formation and the newly proposed divisions within the expanded Berea Formation succession. Coeval terrestrial deposits in Pennsylvania are represented by a lower portion of the Huntley Mountain Formation and by the Spechty Kopf Formation. The Mississippian Subsystem commences with transgressive dark shale deposits of the Orangeville Formation of the Cuyahoga Group in Ohio.

The post-Conewango Group time slice was dominated by major oscillations in climate during the global Dasberg Event and Hangenberg Biocrisis, with associated changes in sea level during the latest Devonian. In Ohio, the Dasberg transgression is marked by the overspread of oxygen-deficient, black shale facies recorded by the Cleveland Member of the Ohio Shale. It is marked by an upward change into non-red, nearshore marine and terrestrial deposits of the Oswayo, Huntley Mountain, and Spechty Kopf formations in New York and Pennsylvania. The aftermath of the initial Hangenberg Biocrisis is recorded by sparsely fossiliferous deposits of the Bedford and Berea formations. One or more subsequent episodes of glaciation produced deposits of diamictite in eastern Pennsylvania and Maryland and a major lowstand disconformity along the base of the Cussewago Sandstone-Berea Formation succession across Pennsylvania and Ohio. Mississippian deposits commence with the transgressive overspread ofdark, offshore shales of the Sunbury Member of the Orangeville Formation in Ohio, which grade eastward (shoreward) into neritic marine deposits in the central Pennsylvania region.

Chapter 5: The Devonian terrestrial system of New York

by Charles A. Ver Straeten. Pp. 211–330, DOI: 10.32857/bap.2023.407.05.

Abstract. Late 18th to early 19th century reports on the rocks of the Catskill Mountains in eastern New York were followed by over 180 years of geological and paleobiological studies of the Devonian terrestrial succession, in the state and up and down eastern North America. Yet, nearly 230 years later these estimated ca. 2.4 km- (1.5 mi-) thick, homogenous strata remain a largely unknown frontier in many ways.

Studies of Devonian terrestrial strata in New York over the last century include two different stratigraphic frameworks. The first, by George Chadwick (1930s–1940s), focused on the Catskill Front to the vicinity of Slide Mountain, highest peak in the Catskills. The second, by Fletcher and Rickard in the 1960s to mid-1970s, attempted to create a broader, more geographically inclusive chronostratigraphic nomenclature throughout the entire Catskills outcrop belt. Recent work indicates that in the field this latter model, based on thick lithosomes of red and gray rocks and conglomerates, is problematic. It can be seen as representing a “second draft” stratigraphic framework, in need of additional work and refinement. At this time, however, too little is known as to how to better ground the existing stratigraphy, or to propose a sound alternate stratigraphic framework for the Catskills succession.

Other major foci in the Devonian terrestrial of New York include paleobotany (1950s–today), petrography (1960s–1980s), fluvial systems (1970s–1990s), and terrestrial arthropods (1980s–2000s). Broader paleobiological studies, in part associated with the Red Hill site in northern Pennsylvania, burgeoned in the 1990s and continue today. Recent Catskills terrestrial research of impact is perhaps largely paleobiological and includes the first complete Eospermatopteris (“Gilboa”) tree, mapping of wellpreserved forest floors, and increasing research on paleosols.

Difficulties in research of Devonian terrestrial strata in New York include: the lateral discontinuity of terrestrial facies and the lack of documented, distinctive marker beds for correlation; little biostratigraphic and geochronologic control; extensive cover in sometimes rugged terrain; too few researchers, and a need for greater cross-disciplinary perspectives and communication.

The purpose of recent and ongoing research by the author is multifold. First to systematically gather various data, such as event deposits, petrography, detrital zircon dating, and palynological biostratigraphy, top to bottom through the succession, initially in the classic Catskill Front to the vicinity of Slide Mountain, in the New York State Department of Conservation “Slide Mountain Wilderness” of the Catskill Park. Second within that succession, to better document depositional history, provenance, and biostratigraphy, and to know the succession more closely. Through this, the larger goal is to test the existing stratigraphic framework and try to ground that stratigraphy in the regional rock record better, or to develop a new stratigraphic framework.

Key issues that remain largely unresolved in Devonian terrestrial strata of New York include: lack of a well-tested, viable, and correlatable stratigraphic framework; a general lack of chronostratigraphic data from palynological/microvertebrate biostratigraphy and radiometric ages from altered air fall volcanic tephra beds; and no systematic documentation of the vertical Catskill succession. Other future studies could include lateral, interstate/province comparisons of variations in provenance/drainage evolution along the Acadian (Acadian-Neoacadian) Foreland Basin and its subbasin known as the Appalachian Basin, via petrography, detrital mineral dating and other methods.