middle paleozoic sequence stratigraphy and ...

International Geoscience Programme (IGCP) Project 591 2nd Annual Meeting and 1st Foerste Symposium

MIDDLE PALEOZOIC SEQUENCE STRATIGRAPHY AND PALEONTOLOGY OF THE CINCINNATI ARCH: PART 1 CENTRAL KENTUCKY AND SOUTHERN OHIO Carlton E. Brett, Patrick I. McLaughlin, Thomas J. Schramm, Nicholas B. Sullivan, James R. Thomka Carlton E. Brett, Bradley D. Cramer, Tammie L.Gerke (eds.)

Cincinnati, Ohio, USA 22nd-23rd July, 2012

www.igcp591.org

International Geoscience Programme (IGCP) Project 591 2nd Annual Meeting and 1st Foerste Symposium

MIDDLE PALEOZOIC SEQUENCE STRATIGRAPHY AND PALEONTOLOGY OF THE CINCINNATI ARCH: PART 1 CENTRAL KENTUCKY AND SOUTHERN OHIO Carlton E. Brett1, Patrick I. McLaughlin2, Thomas J. Schramm3, Nicholas B. Sullivan1, James Thomka1 Carlton E. Brett1, Bradley D. Cramer4, Tammie L. Gerke1 (eds.) 1

Department of Geology, University of Cincinnati, Cincinnati, Ohio 45221-0013, USA. [email protected], [email protected], [email protected]

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Wisconsin Geological and Natural History Survey, Madison, WI 53705 [email protected] 3

Department of Geology and Geophysics, Louisiana State University, E235 Howe-Russell Geoscience Complex, Baton Rouge, Louisiana, 70803, USA. [email protected]

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Department of Geoscience, University of Iowa, Iowa City, IA 52242, [email protected]

Cincinnati, Ohio, USA 22nd-23rd July, 2012

www.igcp591.org

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DEDICATION: THIS GUIDEBOOK IS DEDICATED TO AUGUST F. FOERSTE

August Frederick Foerste taught for 38 years at Steele High School in Dayton, Ohio (just north of Cincinnati), but as an undergraduate at Denison University had already begun describing the geology and paleontology of the Dayton area. Upon his retirement, he was offered a professorship at the University of Chicago, but instead chose to spend the remaining years of his life as a Research Associate at the Smithsonian Institute. As we will see during this meeting, the Dayton area is critical to connecting the Ordovician and Silurian stratigraphy of the Appalachian Basin with that of the Illinois Basin, and his published works over more than three decades have served as the foundation for the stratigraphy of the tri-state region of Ohio, Indiana, and Kentucky. Whereas his stratigraphy has undergone regular revision, recent re-evaluation of the region has begun to demostrate that Foerste’s detailed work was truly incomparable.

The aim of this meeting, hosted on the campus of the University of Cincinnati, is to bring the IGCP 591 community to this critical area for Ordovician and Silurian stratigraphy of the paleocontinent of Laurentia. Additionally, the ability to see multiple epicratonic basins in one meeting is ideal for the 2012 annual theme of IGCP 591: Global Sea Level and Sequence Stratigraphy.

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Acknowledgements We are very grateful for the cooperation, knowledge, and insights gained from Don Bissett, Dan Cooper, Steve Felton, Ron Fine, Bill Heimbrock, Jack Kallmeyer, Jerry Rush and other members of the Cincinnati Dry Dredgers. The Cincinnati Dry Dredgers, North America’s oldest continuously existing amateur paleontological society, very generously supported student attendance at this meeting. In addition, the Geology Department of the University of Cincinnati has facilitated our research and presentation in many ways: we would like to thank Kate Cosgrove, Krista Smilek, Mike Menard, Tim Phillips, and Zhen Zhu Wan all helped in various ways in final preparations for the meeting. UC undergraduate students Joshua Brafford, Dom Haneberg-Diggs, Katherine Finan, Cheyenne Hassan, Cameron Schwalbach, Rachel Thomas, Evan Krekeler, and Sasha Mosser are acknowledged for field assistance and help in many ways. Our work has also benefited greatly from close interaction with colleagues and former graduate students: Sean Cornell, Brooks Ellwood, Steve Holland, Aaron House, Brenda Hunda, Pat McLaughlin, Susie Taha McLaughlin, Dave Meyer, Arnie Miller, Paul Potter, Colin Sumrall, and others Brett acknowledges research support from NSF Grant EAR0819715 and a grant from the Donors to the Petroleum Research Fund, American Chemical Society. Schramm acknowledges research support from the GSA Student Research Grant, Dry Dredgers Paul Sanders Award, and University of Cincinnati URC award. Dattilo acknowledges research support by grants from Indiana University-Purdue University Fort Wayne, from the Purdue Research Foundation, and the American Chemical Society Petroleum Research Fund Grant 50242-UNI8. The work has also benefitted from the contributions of undergraduate students Sasha Mosser, Aaron Morse, and Michael Blair. Tammie L. Gerke and Nicholas Sullivan provided expert assistance in drafting figures. We are also indebted to Tim Phillips, and Dominique Haneberg-Diggs who aided in preparation of diagrams. Walt Connolly of the University of Cincinnati’s copy center worked patiently with us in the duplication of these guides. Finally, Betty Lou Brett assisted in innumerable ways in the preparation of the guidebook and the meeting itself. This is a contribution to IGCP 591.

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TABLE OF CONTENTS DEDICATION………………………………………..……………………………...……………iv. ACKNOWLEDGMENTS……………………………………………………………...………….v. MIDDLE PALEOZOIC SEQUENCE STRATIGRAPHY AND PALEONTOLOGY OF THE CINCINNATI ARCH; by C.E. Brett, P.I. McLaughlin, N. Sullivan, J. Thomka Introduction…………………………………………………………………………...….1. Geologic Setting…………………………………………………………………………..1. Sequence Stratigraphy of Upper Ordovician to Middle Devonian Successions along the Cincinnati Arch……………………………………………………………9. Regional Stratigraphy………………………………………...………………………..11. Upper Ordovician (Mohawkian) Series……………………………………………….11. Upper Ordovician (Cincinnatian) Series……………………………………………....19. Silurian Period: Tutelo Supersequence………………………………………………..26. Kaskaskia Supersequence……………………………………………………………..38. Middle Devonian series…………………………………………..………………….. 39. Broad issues in Sequence and Event Stratigraphy in Mid-Continent Successions……………...……………………………………………………………… 39. References………………......…………………………………………………….……..46. IGCP 591 PRE-MEETING FIELD TRIP ROADLOG, DAY 1…………….………....…...…56. IGCP 591 PRE-MEETING FIELD TRIP STOP DESCRIPTIONS, DAY 1…………………66. STOP 1A. LONG ROADCUT ON I-75 S OF GEORGETOWN, KY. …………...……66. STOP 1B. CUTS ON IRONWORKS PIKE ROAD, DONERAIL, KY………………..66. STOP 2. CUTS ON I-75 AND KY 25 KENTUCKY RIVER, CLAYS FERRY, KY.…67. STOP 2A. CUTS ON I-75 S. OF BRIDGE OVER KENTUCKY RIVER GORGE……67. STOP 2B. CUTS ON I-75 N. OF BRIDGE OVER KENTUCKY RIVER GORGE…...68. STOP 2C. CUTS ALONG RTE. 2328 BELOW THE I-75 BRIDGE…………….…….68. STOP 2D. CUTS ALONG RTE. 2328 SOUTH OF THE I-75 BRIDGE……………….68. STOP 3A. CUTS ON KY RTE 627, BOONESBOROUGH, KY………………………70. STOP 3B. BOONESBOROUGH QUARRY ACCESS ROAD………………………...74. STOP 4. CUTS ON RTE 52 JUST WEST OF RTE 421, LAKE REBA, KY ………….74. STOP 5A. BP STATION ON RTE. 52; WACO, KY…………………………………...77. STOP 5B. DROWNING CUT WEST: LOWER PART………………………………...77. STOP 5C. DROWNING CUT WEST: UPPER PART………………………………....81. STOP 6. WINSTON JUNKYARD; SMALL CUT ON RTE 52………………………..85.

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OPTIONAL STOP. EMMANUEL BAPTIST CHURCH W IRVINE, KY……………87. STOP 7. BARE HILL SLOPE, NORTH IRVINE, KENTUCKY………………………87. STOP 8. FAULTED OUTCROP ON I-64 WEST OF SALT WELL CREEK…………90. STOP 9. CUTS ON EXIT 123 RAMP, EAST OF OWINGSVILLE, KY………….…..91. STOP 10. CUT WEST OF OWINGSVILLE MANOR REST HOME, OWINGSVILLE, KY………………………………………………………………...94. STOP 11. CUTS ON I-64; EAST OF LICKING RIVER ROAD, MOREHEAD, KY…………………………………………………………………………………….96. SUPPLEMENTAL ARTICLE: ORDOVICIAN STRATA OF THE TYPE NORTH AMERICAN MAYSVILLIAN STAGE by T. J. Schramm, C. E. Brett, B. F. Dattilo, and B.B. Ellwood Cincinnatian Sequence Stratigraphy………………………………………………….98. Maysvillian Stratigraphic Sequences……………………………………………..….101. Magnetic Susceptibility…………………………………………………………….....102. References………………………………………………………………………….......103. IGCP 591 PRE-MEETING FIELD TRIP ROADLOG, DAY 2………………………...…...106. IGCP 591 PRE-MEETING FIELD TRIP ROADLOG………………………………..…..…107. IGCP 591 PRE-MEETING FIELD TRIP STOP DESCRIPTIONS, DAY 2……….…….…112. STOP 1A. ROADCUTS RT. 11 EAST OF MAYSVILLE…………………….…...…112. STOP 1B. CUTS ON US RTE 62/68 …………………………………………...…..…112. STOP 2. CUTS ON AA HIGHWAY (KY RTE. 9) NEAR ORANGEBURG, KY.......123. STOP 3. CUT ON RT. 10, WEST OF CABIN CREEK, TOLLESBORO, KY……….124. STOP 4. HIGH ROADCUT ON NORTH SIDE OF AA HIGHWAY, CHARTERS, KY……………………………………………………………………126. STOP 5. CUTS ON AA HIGHWAY (RTE. 9/10) AT HERRIN HILL, KY………… 129. STOP 6A. CUT AT RTE 41 AND HULL ROAD, JACKSONVILLE, OHIO…..……132. STOP 6B. SHALE PIT, BRUSH CREEK RACEWAY, JACKSONVILLE, OHIO….134. STOP 7. ROADCUT ON RTE. 32 AT MEASLEY RIDGE, PEEBLES, OHIO..…….135.

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M iddle Paleozoic Sequence Str atigr aphy and Paleontology of the C incinnati A r ch Carlton E. Brett1, Patrick I. McLaughlin2, Nicholas Sullivan1 and James Thomka1 1

Department of Geology, University of Cincinnati, Cincinnati, OH 45221 Wisconsin Geological and Natural History Survey, Madison, WI 53705

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INTRODUCTION Middle Paleozoic rocks exposed in Kentucky and adjacent southern Ohio and Indiana have a long history of study. Early workers including Hall (1879, 1882); Linney (1882), Girty (1898), Butts (1915), and Foerste (1896, 1897, 1905, 1906, 1917,1929, 1931a,b, 1935), and Savage (1930) documented the faunas and stratigraphy of these rocks in considerable detail. Stratigraphic syntheses of Ordovician and Silurian stratigraphy were provided by Peterson, 1981; Shaver et al. 1986; and Droste and Shaver, 1986 a-f). Conodont studies of Rexroad et al. (1965, 1978), Rexroad (1980), and Rexroad and Kleffner (1981) provide a regional biostratigraphic framework for the Silurian (Conkin and Conkin, 1972, 1976, 1980; Conkin et al., 1973, 1976), and syntectonic sedimentation (Ettensohn, 1987, 1992, 2004). Moreover, recent quarrying activity and construction of major highways around the Tristate (Ohio, Kentucky, Indiana) area has provided a number of exceptionally well-exposed and accessible fossiliferous outcrops. In this excursion, we will examine several exposures of strata ranging in age from the Late Ordovician (Sandbian, Katian or Mohawkian through Cincinnatian in North American terminology) to the mid Silurian (Llandovery, Wenlock), and will use these sections to demonstrate the relationships between sequence stratigraphy, correlations, and the fossil record. In the present excursion we will explore aspects of sequence stratigraphy, fossil distribution, bioevents and taphonomy in relation to depositional processes in mixed siliciclastic-carbonate sequences of the classic middle Paleozoic of the Cincinnati Arch. We will demonstrate some predictable aspects of the paleontological record in relation to sequence stratigraphy and depositional environments. In addition, we will consider numerous remaining problems of correlation, biostratigraphy, taphonomy and the paleontology of bio-events. We will particularly emphasize patterns that can be discerned across time scales. The rocks of the Cincinnati Arch are structurally simple and exceptionally well exposed in hundreds of quarries, roadcuts and streambeds (Fig. 1). They are richly fossiliferous and show clearcut subdivision into depositional sequences in mixed siliciclastic-carbonate facies. Thus, they provide a natural laboratory for the study of the relationships of paleontology/taphonomy and sequence stratigraphy. GEOLOGIC SETTING The Cincinnati arch is a long-lived positive basement structure that was most recently active as a forebulge during the late Paleozoic (Ettensohn, 1992, 2008). Erosion of the center of the arch (Jessamine Dome) has exposed the oldest strata of the Tri-state region: the Upper Ordovician Sandbian High Bridge Group is exposed in fault blocks along the Kentucky River near Lexington and Frankfort, KY (Fig. 2).

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Figure 1. Map of the study area showing major Ordovician and Silurian outcrop areas. A) Paleogeographic map of study area showing sediment sources and prevailing storm wind tracts. B) Map of Tri-state area Indiana (W side), Ohio, and Kentucky (S), showing present outcrop distribution; note bullseye pattern in pale gray in center is crest of Cincinnati Arch outcrop belt of Upper Ordovician units. Words in pale gray indicate facies/environments, which shallow to the northwest from peritidal to deep subtidal. Figure courtesy of B. Datillo.

These strata reflect primarily deposition in marine environments along the westward edge of the Appalachian foreland basin and bordering interior platform. During the Late Ordovician to Middle Mississippian this region was the site of mixed shallow water carbonate platform and muddy shelf to basin margin deposition. As a result of four major orogenic pulses, the region intermittently received a supply of fine-grained siliciclastic muds and silts from the east and southeast. The exact mechanisms by which these extra basinal sediments were transported and deposited remain an important area of study. While it might be anticipated that areas several hundred kilometers from the hinterland would receive only minor and gradually deposited siliciclastic sediments, it is evident from the study of taphonomy that some muds and silts accumulated rapidly as rapid pulses of up to several centimeters of sediment in very brief intervals of time, no more than hours to days in duration. These sedimentary events may reflect either muddy plumes that were carried far offshore following major flood events or alternatively, bottom flows such as distal storm beds or turbidites in which previously deposited sediment from more proximal upslope regions was resuspended and carried in turbulent bottom flows.

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Figure 2. Regional basement structures and outcrop belts of eastern North America (modified from Ettensohn, 1992). Locally supplied carbonate sediments are abundant and diverse. They include micrite of uncertain origin, but probably supplied either via microbial precipitation or algal degradation, as well as abundant bioclasts representing skeletons of primarily invertebrate organisms, most notably corals, bryozoans, brachiopods, and crinoids. Intervals of bioclastic limestone deposition appear to have alternated with times of extensive carbonate mud deposition. This alternation may reflect both

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climatic and hydrodynamic effects. Deposition of lime-mud appears to be linked with warm, semiarid climates (see Patzkowsky and Holland, 1993), which favored microbial production of fine-grained carbonate sediment (Fig. 3). The abundance of micrite in some intervals such as the middle Silurian also suggests predominantly low energy environments in the interior of the Wabash platform. A scarcity of body fossils in many of these deposits remains enigmatic (see Peters, 2007); however, it may reflect low oxygen as well as slightly hypersaline conditions in the low-energy platform seaway. Moreover, certain units, such as the Waldron Shale, undergo very abrupt lateral transitions from richly fossiliferous facies to nearly barren, dark gray mudstones within just a few kilometers. This pattern suggests shallow water stratification such that denser and perhaps hypersaline, dysoxic water in slightly deeper topographic depressions did not mix freely with overlying oxic, normal marine water. Paleogeography: During the studied time interval, Late Ordovician to Middle Devonian, spanning approximately 100 million years (450 to 380 Ma), the field trip area lay predominantly in the southern subtropics, approximately 25-30° South latitude in the Late Ordovician and perhaps somewhat farther south about 35-40° S by Early Devonian time (Fig. 3). This was followed by rather rapid northward drift of the craton during the Carboniferous. A)

B)

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Figure 3. Paleogeographic globes for the (A) Late Ordovician (~450 Ma), (B) middle Silurian (~430 Ma), (C) Early Devonian (~400 Ma). (http://jan.ucc.nau.edu/~rcb7/mollglobe.html).

Climate: The Cincinnati Arch region lay within the subtropical hurricane-dominated belt throughout the Late Ordovician to Middle Devonian. Climates during this interval were predominantly warm and humid to arid (Scotese, 2001, 2009; Cocks and Torsvik, 2002). Beginning in the Late Ordovician, the local climate may have been intermittently semi arid and it is clear that during the Late Silurian, the region was prone to hypersalinity. Major evaporite deposits accumulated nearby in the Michigan Basin and northern Appalachian Basin. The tendency toward hypersalinity may have strongly influenced organism distribution at times. The paleogeographic evolution of eastern Laurentia (Fig. 3) during the Late Ordovician has been debated for some time (see introduction in Kolata et al., 2001 and Ettensohn et al., 2002a for review). The current consensus suggests that the Taconic Orogeny, which initiated in the late Middle Ordovician, was the result of a series of collisions of island arcs with the southern margin of Laurentia (Fig. 3; Stanley and Ratcliff, 1985; Rowley and Kidd, 1981; Bradley and Kidd, 1991)

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resulting in at least two, and probably three, Taconian tectophases (Ettensohn, 1992; Ettensohn and Brett, 1009. 2002). The Blountian Orogeny, representing the first tectophase, occurred during Sandbian (Turinian or Blackriveran) time and is recorded as foreland basin deposits in eastern Tennessee and Virginia. This first tectophase apparently had little regional effect, as most of Laurentia remained a shallow carbonate platform with little topographic relief throughout Turinian time (Cressman, 1973; Cressman and Noger, 1976; Keith, 1988; Kolata et al., 2001; Ettensohn et al., 2002a; Brett et al., 2004). The second (Vermontian) tectophase begins in the early Chatfieldian. The Turinian/Chatfieldian contact is marked by a widespread and well-studied K-bentonite, the Millbrig (Huff et. al, 1992). A major lithologic change occurs just above this contact: micritic facies, which typify much of the Mohawkian up to this point, change abruptly to mixed skeletal limestones and shale, a motif that endures throughout the remaining Ordovician. This shift in lithology has been attributed to a switch from tropical- to temperate-style carbonate production, induced by increased differentiation of the carbonate platform into a series of basins and arches (resulting in increased upwelling), increased turbidity, and sea level rise (Holland and Patzkowsky, 1996; Pope and Read, 1997). However, detailed regional studies (Cressman, 1973; McLaughlin et al., 2004; Brett et al., 2004) provide strong evidence for the last assertion. Facies mapping within individual Chatfieldian-Edenian unconformity-bound depositional sequences throughout broad portions of eastern North America suggest the presence of a peripheral foreland basin on the southern margin of Laurentia, but otherwise little differentiation of the craton during early Chatfieldian time. Recognition of the Guttenberg C13 isotopic excursion in early Chatfieldian (mid-Rocklandian) age strata of similar facies across most of eastern North America (Young et al., 2003) supports this interpretation. Through the remaining Chatfieldian Stage (early Katian) differential subsidence occurred in areas defined by known basement weakness (Black and Haney, 1975), resulting in development of a number of related topographic depressions and swells. Topography of the local seafloor was variably influenced by far-field tectonics associated with local crustal flexure and movement on deep-seated basement faults (Figs. 4, 5). During the Late Ordovician the Lexington platform extended from the Sebree Trough near the Kentucky-Indiana border in the west to the Taconic foreland basin in the east. The Sebree Trough extended from modern day western Tennessee to northern Ohio (Fig. 4; Kolata et al., 2001; Ettensohn et al., 2002a), where it eventually connected with the Taconic foreland basin during Edenian time (McLaughlin et al., 2004). The Lexington Platform included the area between the Sebree Trough and the Taconic foreland basin. During midChatfieldian time (early Shermanian) the Lexington Platform underwent rapid, tectonicallyinduced reconfiguration, including: 1) subsidence in the area of modern southern Kentucky and northernmost Tennessee (coincident with the position of the Cambrian age Rome Trough; Fig. 5), 2) uplift of a linear region extending from just west of Frankfort, Kentucky eastward to at least Winchester, Kentucky (perhaps as far as Virginia), and 3) increased subsidence and widening of the Sebree Trough. The reorganization of topography is attributed to far-field tectonic forces induced by an episode of increased thrust loading during the Vermontian tectophase and is coincident with an introduction of multiple widespread soft-sediment deformation horizons and Kbentonites on the Lexington Platform (see below; Fig. 10). The Sebree Trough and adjacent deeper portions of the Lexington Platform were largely in-filled during the Edenian when a major pulse of siliciclastic mud accumulation occurred across much of southern Laurentia. Ettensohn et al. (2002a) suggested that continued loading of the continental margin might have actually produced uplift/tilting of the foreland basin, resulting in this rapid redistribution of a large quantity of finegrained siliciclastics across a broad portion of the craton.

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Figure 4. Map of eastern Laurentia during the late Ordovician showing major tectonic and topographic features. Red box denotes study area. The Sebree Trough remained prominent into the early Cincinnatian (late Caradoc, middle Katian) during deposition of the Kope Formation. The latter shows a strong facies change from shallow mixed carbonate pack- and grainstones and siliciclastics typically assigned to the upper Clays Ferry Formation in the Jessamine Dome area to typical shale/mudstone dominated Kope Formation of the Cincinnati region, to dark shales commonly referred to as “Utica Shale” some 50 km northwest of Cincinnati. However, during the Edenian the trough appears to have become largey infilled such that facies of the upper Kope and Fairview formations are more nearly uniform from south to north although some increase in shale content in northern facies persists upward through Maysvillian (early Ashgill?) stage suggesting a gentle depression to the north-northwest. Late phases of erosion in the orogen produced the extensive Juniata-Queenston molasse wedge over much of eastern Laurentia, overfilling in the Taconic foreland. The reddish marginal marine to non-marine strata extended as far west as eastern Ohio and Kentucky as the Peachersville Member of the Drakes Formation. A late tectophase of the Taconic Orogeny, the Medina phase produced a new pulse of subsidence far west of the earlier basins during deposition of the Early Silurian (Rhuddanian-early Aeronian):

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Tuscarora-Medina clastic wedge (Ettensohn and Brett, 2002). Offshore silicclastics were largely confined to areas of the present Appalachian region, but muds spread as far west as Kentucky during deposition of the upper Brassfield and Noland formations. During the late Telychian, collision of Baltica with the northern part of Laurentia produced the Scandian phase of the Caledonian Orogeny (Cocks and Torsvik, 2002); however, a southward extension of this event may be recorded in the so-called Salinic Orogeny. This orogeny may have resulted from westward subduction and collision of Laurentia in the Maritime region with Avalonian terranes (Reading Prong; Fig. 3B). The Salinic occurred in two tectophases and created a new retroarc foreland basin with somewhat different orientation than the Taconic basins (Ettensohn and Brett, 1998).

Figure 5. Major basement structures of the eastern United States (modified from Thomas, 1991). A localized structural high was developed in the area from Frankfort to Winchester Kentucky. Upwarping of this region may reflect the presence of isolated fault blocks resulting from the intersection of two major fault systems, the Iapetan Kentucky River fault system and the Lexington fault zone, localized along the Proterozoic Grenville front (Ettensohn, 1992; Fig. 5). Likewise, the Taconic collision appears to have reactivated old zones of structural weakness, producing subsiding regions both south and north of the Lexington platform. In particular the narrow Sebree trough (10s of kilometers wide) in western Ohio, southeastern Indiana, and western Kentucky, formed a locus of deeper water sedimentation during the Chatfieldian to early Cincinnatian interval. This trough was an under-filled basin that accumulated dark shales and thin allodapic carbonates synchronously with the production of shallow water shoal facies in the Lexington platform. However, the trough

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was largely infilled with fine-grained siliciclastics (mainly black and dark gray graptolite bearing shale) by Maysvillian time. During the Late Ordovician into the Early Silurian far-field tectonics appear to have produced an area of regional uplift perhaps owing to structural inversion of pre-Grenvillian Mid-Continent rifts (Rast and Goodman, 1994). During the Silurian to Middle Devonian the study area was influenced by the presence of a north-northeast to south-southwest trending area of relative uplift the FindlayAlgonquin arch, which largely paralleled the trend of the pre-existing Sebree trough. This positive feature, a precursor of the present day Cincinnati arch, probably records the development of a forebulge in the midcontinent associated with tectonics in the eastern mountain belts. The presence of this structure is indicated by the thinning and partial truncation of early Silurian strata in the vicinity of Western Ohio and eastern Indiana (Fig. 6). An additional high area existed to the southeast, a precursor of the Waverley arch with a crest southeast of Maysville, Kentucky (Ettensohn, 1992).

Figure 6. NW-SE cross-section of Silurian sequences in southwestern Ohio showing convergence of multiple unconformities to the northwest. This evidence indicates the presence of an intermittently uplifted submarine high, the Algonquin-Findlay arch, a possible precursor of the Cincinnati Arch, during the Silurian.

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SEQUENCE STRATIGRAPHY OF UPPER ORDOVICIAN TO MIDDLE DEVONIAN SUCCESSIONS ALONG THE CINCINNATI ARCH General Sequence Stratigraphic Concepts Applied to Mixed Siliciclastic-Carbonate Sucessions: Upper Ordovician to Middle Devonian mixed siliciclastic-carbonate sequences exposed in the Cincinnati Arch and adjacent regions are divisible into a series of small- (0.5 to 2 meters thick and probably representing a few tens of thousands of years; fifth- and sixth-order), medial (3-10 meters thick and representing hundreds of thousands of years; fourth-order), and large-scale (typically 10 to 100 meters of 1 to a few million years duration; third-order) sedimentary cycles (Coe, 2005; Cateneanu, 2006; Fig. 7). These are interpreted in the context of sequence stratigraphy, following general concepts outlined by Sloss (1963; 1981);Vail et al. (1977), Van Wagoner (1991), Van Wagoner and Bertram (1995), and more recently updated in Coe (2005) and Cateneanu, 2006).

Figure 7. Idealized sequence stratigraphic successions for mixed silciciclastic-carbonate successions of differing temporal and thickness scales. Abbreviations: ETST: early transgressive systems tract; FSST: falling stage (regressive) systems tract; HST: highstand systems tract; LTST: late transgressive systems tract.

Each depositional sequence commences with a sharp, typically nearly planar erosion surface that is interpreted as a sequence boundary. In many cases, this surface demonstrably truncates subjacent strata forming a regionally angular unconformity. Certain of the unconformities well displayed in the Louisville area (e.g., Cherokee, Wallbridge, and Taghanic unconformities) are major megasequence bounding surfaces at which several million years are unrepresented (Sloss, 1963, 1981). Most of these disconformities are actually composite surfaces and reflect the convergence of separate unconformities onto relatively positive areas associated with the inner platform and/or

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forebulge. In many cases, for which the disconformity is minor, the surface displays a sharp contact between deeper and shallower water facies: a facies dislocation. Most all disconformities are actually E/T surfaces, i.e., combined lowstand erosion surfaces and transgressive ravinement (shoreface erosion) surfaces; the latter have erased any record of subaerial exposure in most cases. Transgressive systems tracts in mixed siliciclastic-carbonate successions are typified by compact skeletal pack- or grainstones and rudstones, a few meters thick, with stacked burrowed firmgrounds or hardgrounds. Such beds are typically enriched in stenotopic benthic taxa, such as corals, bryozoans, stromatoporoids and large crinoids. A second type of surface, which is easily identifiable in most middle Paleozoic sequences of the western Cincinnati Arch is a sharp contact between compact, usually skeletal, carbonates and overlying shaly, nodular carbonates or shales reflecting low energy, deeper water facies (Fig.7). These surfaces are commonly marked by hardgrounds with phosphatic or pyritic crusts, shelly lags or corrosion surfaces on older carbonates (McLaughlin and Brett, 2007; McLaughlin et al., 2008). In many cases there is evidence for further back-stepping and deepening of a few minor cycles above these surfaces; hence, they do not represent the true end of the TST, but rather a maximum sediment starvation surface (SMS), probably formed during maximum rate of sea-level rise, sequestering of siliciclastics and drowning of carbonate platforms. Interestingly, biostromes or small bioherms are typical of these intervals. Highstands are typified by deeper, offshore successions that show some tendency to shallow upward from deepest facies near their bases. For pure carbonates these changes may be recorded in thinly bedded skeletal hash and micritic limestone beds or simply as fine grained, tabular, silty dolomicrites, typically with abundant bioturbation and firmground horizons that may be accentuated by layers of chert nodules. In mixed siliciclastic carbonate sequences they may be very shaly, nodular carbonates. In deep, offshore facies, such as the parts of the Ordovician Utica Shale in the Sebree trough, these are mainly black shales, generally with knife sharp boundaries that reflect maximum sediment starvation and/or maximum flooding surfaces. A third type of boundary, developed in some sequences, is a somewhat irregular to channelized surface overlain by sandy skeletal carbonates (calcarenites), laminated calcisiltites, and, in some cases, quartz siltstones (Fig. 7). These erosive surfaces are not sequence boundaries, as they do not show evidence of subaerial exposure or major regional truncation. They lie well below identifiable sequence boundaries. These beds are typically sparsely fossiliferous except for highly abraded/corroded skeletal grains, though widely scattered, well-preserved fossils may occur. Such intervals are interpreted as falling stage (forced regressive) systems tracts (FSST) and their sharp basal surfaces as marine erosion surfaces associated with forced regression that focused wave and current erosion on the seafloor. They may include discrete, well-preserved traces such as escape traces, Planolites, Skolithos and others. In Devonian and younger successions silty beds are typically rich in Zoophycos; however, these traces are rare or absent in older sediments in the Cincinnati Arch region. Synsedimentary deformation is also particularly typical of these FSST packages and may include intervals of ball-and-pillow deformation, broken and rotated slabs, synsedimentary slumping, mud diapirs and flame structures. These are interpreted as seismically induced deformation related to foundering and minor slumping on slightly steepened ramps (Pope et al., 1997; McLaughlin and Brett, 2004). The mixture of rapidly deposited carbonate/clastic silts and interbedded thixotropic muds may have made these intervals especially prone to deformation during seismic shocking from local movement along basement faults associated with far-field tectonic stresses. Deformed beds are commonly cut by sequence boundaries.

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REGIONAL STRATIGRAPHY The following sections outline the stratigraphic units, from Upper Ordovician (Edenian) to Late Silurian, as seen of the Cincinnati Arch, as various sections around the Cincinnati Arch, Kentucky examined along the I-71 corridor. Figure 8 provides a generalized summary of this portion of the stratigraphic column. UPPER ORDOVICIAN (MOHAWKIAN) SERIES: SANDBIAN TO LOWER KATIAN (CARADOC) STAGES Tippecanoe (Creek) Megasequence M3-C6 The Upper Ordovician strata exposed near the crest of the Jessamine Dome in north-central Kentucky (Fig. 2, 3) are richly fossiliferous and record a broad spectrum of carbonate litho- and biofacies. This paper addresses facies, depositional environments, and sequence stratigraphy of the High Bridge Group, Lexington Limestone and immediately adjacent units. We illustrate the use of sequence and event stratigraphy, including hardgrounds, K-bentonites, and seismites, in interpreting the facies transitions. Upper Ordovician stratigraphy in the Jessamine Dome area has been the subject of many studies (see McLaughlin et al, 2004 for brief summary). The varying backgrounds of the authors have resulted in a variety of interpretations and a plethora of overlapping, named stratigraphic units. The most recent comprehensive lithostratigraphic works are those of Cressman (1973) and Weir et al. (1984) and the most recent large-scale sequence stratigraphic analyses were done by Holland and Patzkowsky (1996), Pope and Read (1997) and McLaughlin et al. (2004). In this paper, we incorporate aspects of the previous studies to form a base line upon which we have built a high-resolution sequence stratigraphic framework, incorporating repeated comparison of facies, cycle stacking patterns, and event beds between nearby outcrops/cores, throughout the entire study interval. The resulting sequence stratigraphic interpretation varies in many subtle, but fundamental aspects from those of previous authors, including: the motif of depositional sequences, the expression of systems tracts, the sedimentary record of sea level rise/fall and subsequent siliciclastic sediment starvation/influx, and recognition of multiple regional erosion surfaces (Fig. 8). Sequence M1- M3 (Camp Nelson and Oregon Formations) The High Bridge Group represents the oldest strata exposed in the Tristate region and is known from outcrops around the Kentucky River, including the picturesque “Palisades of the Kentucky River” south of Lexington and in cement mines around the Ohio River area. The High Bridge Group is generally assigned to the Turinian (Blackriveran of older usage) Stage in North America and corresponds to the upper part of the Sandbian Stage of international usage. These beds are equivalent to other well known micritic limestone successions in eastern North America, including the Black River Group in New York State, the Ridley-Lebanon-Carters succession in Tennessee, the Chickamauga Group in the Appalachians (including Moccasin reddish limestones) and the Plattin and Platteville-lower Decorah succession of the upper Mississippi Valley. It represents a peak time for shallow carbonate bank development in eastern Laurentia following exposure during development of the major Knox Unconformity (Fig. 8). Sequence M1- M3 (Camp Nelson and Oregon Formations) Overall, the succession comprises over 150 meters of micritic limestones and dolostones but only a maximum of 134 m is exposed at the Palisades. In the subsurface, the Camp Nelson is observed to conformably overlie the Wells Creek Formation (Whiterockian), comprising dolomitic, chert clast conglomerates, green and reddish shales that in turn overlie the major Middle Ordovician Knox Unconformity.

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Figure 8. Generalized time-stratigraphic chart of Ordovician strata of the Creek megasequence in eastern North America, showing major unconformities that separate 2nd order sequences. Note that prior to the Turinian (late Sandbian) most time is represented by unconformities. Typical colors of shales are shown in each sequence. Curve on right hand side shows general trends in carbon isotopes; note positive excursions in the Turinian to early Chatfieldian and in the Hirnantian.

The lower parts of the Camp Nelson succession remain poorly known but comprise a series of meter-scale cycles that include massive bioturbated, sparsely to moderately fossiliferous wackestones with thin packstones containing abundant gastropods, small brachiopods and leperditian ostracodes. Tops of cycles may show thin yellowish weathering dolomitic shales with desiccation cracks (Cressman and Noger, 1976; Kuhnhenn, et al., 1981). The upper portion of this major sequence is marked by a distinctive, meter-thick pale olive gray shale with desiccation cracks and possible stromatolitic lamination near the top. This shale is sharply overlain by fossiliferous argillaceous limestone that appears to record a new transgessive systems tract. This interval is followed by a second upward shallowing succession that culminates in laminated dolomitic wackestone, referred to as the Oregon Formation. The Oregon is typified by blotchy dark mottles (“leopard spots” or “Kentucky River marble”; Fig. 9) and includes abundant

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evidence of subaerial exposure including desiccation cracks and possible oxidation structures in the mottles; it is sparsely fossiliferous but yields some leperditian ostracods and gastropods (Kuhnhenn, et al., 1981).

Figure 9. Typical “leopard spot” lithology of Oregon Formation or “Kentucky River marble”; Boonesborough, KY.

Sequence M-4 (Tyrone Formation) The upper High Bridge Group consists of about 25 to 30 m of Tyrone Formation strongly micritic limestone mostly lime mudstones and wackestones commonly with fenestral fabrics. The Tyrone represents essentially sequence M4 of Holland and Patzkowsky (1996), but as with other successions it is probably divisible into two sequences as outlined below. The Tyrone also contains a number of thin K-bentonite beds, perhaps as many as 19 or 20 (Conkin and Conkin, 1983), including a cluster of three, prominently displayed at Boonesborough, KY, referred to as the 1st and 2nd Boonesborough K-bentonites, as well as two of the most widespread ash beds in the geologic record, the Deicke and Millbrig K-bentonites (Huff and Kolata, 1993; Kolata et al, 1996). The latter is typically at or near the top of the Tyrone although it is locally removed by erosion at the M4/M5 sequence boundary below the base of the Curdsville Member of the Lexington Limestone. The very important Millbrig K-bentonite has been dated using U/Pb radiometric dating of zircons at 453-454 Ma (Huff et al., 1992). The Millbrig has also been used to establish the base of the Chatfieldian Stage. The Tyrone appears to reflect a large-scale cycle. The basal portion comprises fosiliferous wackestones with abundant fossils including rugose corals, Tetradium, and gastropods and thin “birdseye” micritic limestones. At or just above the first Boonesborough K-bentonite, the appearance of argillaceous, desiccation cracked mudstones and calcareous-dolomitic shales signals the beginnings of a late highstand phase. The second Boonesbrough K bentonite and several other thin clay layers that may represent other ash horizons occur in the lower member. Following a small-scale cycle with a return to somewhat more offshore burrow mottled dolomitic limestones and dolostones (sometimes also assigned to the Oregon Formation), laminated and, locally desiccation-cracked shale and shaly dolostone succession, herein referred to as the “Herrington Lake member” (Fig. 10). The middle portion of the Tyrone comprises a highly argillaceous, unfossiliferouslaminated and locally desiccation cracked shale and shaly dolostone succession, herein referred to as the “Herrington Lake member” (Fig. 10).

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Figure 10. Middle shaly zone or “Herrington Lake” member overlain sharply by massive upper member of Tyrone Formation; Rt. 627 cut, Boonesborough, KY.

This shaly interval in the middle of the Tyrone is widespread and suggests a relatively strong input of siliciclastics at this time during a late highstand or falling stage of the lower Tyrone sequence; this portion of the section lying below the Diecke and Millbrig levels correlates approximately with the level of the red siliciclastic dominated Moccasin Formation in the southern Appalachians and may record progradation of mud and silt into the central Kentucky area from the Blountian orogenic belt in the southern Appalachian regions during base level lowering. The upper portion of the Tyrone includes the main upper cluster of K-bentonites and comprises the classic “birdseye” limestone facies, equivalent to the Lowville Limestone of New York State. This interval typically shows a triumverate of K-bentonites with the lower commonly brilliant green Deicke (Pencil Cave of Kentucky workers) separated by about 2-3m from a yellowish middle unnamed K-bentonite and that in turn separated by 2-3m from the important Millbrig K-bentonite (Fig. 11; Kolata and Huff, 1993). This upper Tyrone, which sharply overlies the Herrington Lake member at a discontinuity that may represent a sequence boundary (Fig. 10), comprises pale gray to white weathering micritic limestones (lime mudstones to wackestones); facies range from laminated to very fine grained “dove gray” micrites with typical fenestral fabrics (“lutites”) to burrow mottled wackestones. Beds adjacent to the Millbrig appear to be more highly fossiliferous and may even include biostromes of Tetradium as well as abundant leperditian ostracodes, some silicified, gasropods, nautiloids and other fossils. Hence, this portion of the section records deepening to offshore facies with the highstand. The uppermost beds of the Tyrone, apparently above the Millbrig are thick-bedded to massive micrites that may record a final minor sequence in the High Bridge Group. This succession might be equivalent to the Watertown Member of New York.

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Figure 11. Deicke K-bentonite within Tyrone Formation; overlain by fenestral micritic limestone. Rt. 27 roadcut, Camp Nelson, KY.

Sequence M5A (Curdsville-Logana Members of Lexington Limestone) The uppermost Sandbian age basal Lexington Limestone rests upon a major unconformity, which separates it from the underlying Tyrone Formation (Figs. 8, 12). This is a sharp, slightly wavy surface that demonstrably cuts out several meters of the upper Tyrone Formation (Cressman and Noger, 1976). The typically fenestral micrites of the upper Tyrone contain a series of useful markers in the form of K-bentonites (Huff et al., 1992; Conkin and Dasari, 1986) that demonstrate the regional truncation at the base of the Lexington (Cressman, 1973). The Curdsville is dominated by grainstone facies and contains multiple hardgrounds: it is designated the TST of the M5A sequence (McLaughlin et al., 2004). The Curdsville locally contains a diverse and well-preserved echinoderm fauna (see Sumrall and Deline, 2009), which was previously misconstrued as indicating a “Kirkfieldian age” (terminology of Kay, 1948). However, isotopic studies of Bergström et al. (2010) confirm that the Curdsville lies below the well-known GICE (Guttenburg isotopic excursion), which commences in the upper Curdsvillelower Logana; the Sandbian-Katian stage boundary also coincides approximately with this level. Thus, as predicted based upon sequence stratigraphy, the Curdsville and Logana record a TST-HST couplet of Rocklandian age, approximately equivalent to the Selby-Napanee succession of the classic New York-Ontario area. The upper contact of the Curdsville is inferred to represent a maximum starvation surface, overlain by shales and thin calcisiltites (lutites) of the Logana Member, interpreted as the HST of sequence M5A. The Napanee of New York and laterally correlative Logana have sometimes been interpreted as shallow lagoonal sediments. However, the regional distribution of these facies suggests a widespread deepening event, probably associated with the Nakkholmen transgressive event identified by Nielsen (2004). This is indicated by the occurrence of the major Guttenburg positive isotopic excursion in the Logana (Bergstrom et al, 2010). The FSST of the M5A sequence is recognizable as nodular packstones and calcarenites of the lowermost Grier in south-central Kentucky, but is more cryptic in other parts of the study area.

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Figure 12. Generalized lithostratigraphy and sequence stratigraphy of the Mohawkian: Chatfieldian Stage (lower Katian) strata in the Jessamine Dome area of central Kentucky.

The upper contact of the Curdsville is inferred to represent a maximum starvation surface, overlain by shales and thin calcisiltites (lutites) of the Logana Member, interpreted as the HST of sequence M5A. The Napanee of New York and laterally correlative Logana have sometimes been interpreted as shallow lagoonal sediments. However, the regional distribution of these facies suggests a widespread deepening event, probably associated with the Nakkholmen transgressive event identified by Nielsen (2004). This is indicated by the occurrence of the major Guttenburg positive isotopic excursion in the Logana (Bergstrom et al, 2010). The FSST of the M5A sequence is recognizable as nodular packstones and calcarenites of the lowermost Grier in south-central Kentucky, but is more cryptic in other parts of the study area. Sequence M5B (lower and middle Grier Members of Lexington Limestone) The lower Grier Member is a grainstone-dominated interval that lies disconformably upon the upper Logana or lowermost Grier and is interpreted as the TST of the M5B sequence. It is approximately equivalent to the Kirkfield (Kings Falls) grainstones of Ontarion and New York

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Figure 13. Contact of Sulfur Well and Stamping Ground members; note stromatoporoid about a meter above the contact; I-75 cut at Georgetown, KY.

(Brett et al., 2004). The lower Grier is sharply overlain by the middle Grier, an interval of shaly nodular Prasopora-rich packstones that exhibits well developed small-scale cyclicity. The middle Grier is designated as the HST of the M5B sequence. The M5B sequence has not been as intensely scrutinized as the surrounding sequences, primarily due to limited outcrop exposure; further study may reveal the presence of a FSST, but at this point no such unit has been discerned. Sequence M5C (upper Grier- Macedonia-Faulconer submembers) The upper Grier Member, dominated by skeletal grainstone facies is interpreted as the TST of the M5C sequence. It has a sharp contact with the underlying middle Grier, which may be unconformable. It is sharply overlain by Prasopora-rich shales and calcisiltites of the Macedonia member. The contact between these two units is marked by a mineralized hardground interpreted as the maximum starvation surface. The Macedonia bed (submember) forms the lower part of the HST and is sharply overlain by a shallowing upward succession of shaly nodular wacke-packstones of the Faulconer submember. The uppermost Faulconer is dominated by fenestral micrite facies in the southern part of the study area, interpreted as the FSST (Fig. 12). Sequence M6A (Salvisa-Cornishville-Brannon-Donerail) The Salvisa-Cornishville member rests on an erosion surface that truncates a few meters of the underlying Faulconer member in south-central Kentucky, and is interpreted as the TST of the M6A sequence. The heavily mineralized hardground that at the upper contact of the Salvisa-Cornishville is interpreted as the maximum starvation surface. The calcisiltite and shales of the overlying Brannon are interpreted as the HST; these beds are noted for extensively deformed zones (Fig. 14). The forced regression surface is a planar to channel-form erosion surface that marks the contact between the Brannon and the overlying informally named Donerail member.

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Figure 14. Deformed “pinstriped facies” interpreted as seismites in the Donerail member of Lexington Limestone; I-75 cut, Georgetown, KY.

Sequence M6B (Sulphur Well - Stamping Ground -Strodes Creek - Greendale - lower Devils Hollow Members) We interpret the sharp basal contact of the Sulphur Well on the Donerail as a sequence boundary (Figs. 12, 13). The Sulphur Well Member is interpreted as the TST of the M6B sequence. The closely spaced, commonly pyrite coated (rusty weathering) discontinuities near the top of the Sulphur Well Member are hardgrounds associated with sediment starvation. Clustering of these hardgrounds near the top of the Sulphur Well indicates a condensed section associated with a maximum starvation surface. The Stamping Ground, Strodes Creek, and Greendale together form a complex HST. The Sulphur Well and the Stamping together, and similarly the Strodes Creek and the Greendale together, can be considered TSTs and HSTs of smaller scale (4th-order) sequences. The FSST of the M6B sequence is designated as the calcarenites and laterally equivalent green desiccation-cracked mudstones of the lower Devils Hollow. Sequence M6C (upper Devils Hollow - Bromley Members) The widespread skeletal grainstones of the upper Devils Hollow Member are interpreted as the TST of the M6C sequence. A mineralized hardground at the top of the Devils Hollow is interpreted as a maximum starvation surface. The overlying Bromley Shale (lower shale, and the Peaks Mill limestone, and Gratz shaly submembers) form a complex HST. Like the underlying sequence, the upper Devils Hollow and lower Bromley Shale pair and, similarly, the Peaks Mill and Gratz pair, can be considered TSTs and HSTs of smaller scale (4th-order) sequences. The FSST of the M6C sequence is designated as the Locust Creek member, a fine-grained grainstone (calcarenite) with distinctive “pinstriped” lamination, possibly of tidal origin (Fig. 14). The grainstones are interbedded with thin calcareous mudstones and in nearly all localities in the Cincinnati Arch this 1-2 m thick interval shows extensive deformation in at least three levels. These deformed beds have been discussed in detail by McLaughlin et al. (2004) and are interpreted as seismites.

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Presumably, the loading of rapidly deposited carbonate sands and silts onto mud layers set up instabilities and during seismic shock events the layers were variably deformed into ball-andpillow to saucer-like masses separated by thin, breccia-filled, muddy diapirs. Many of the deformed layers are truncated at submarine erosion surfaces, some of which are bored hardgrounds, proving that the deformation of the sediments was penecontemporaneous with deformation and probably occurred on the seafloor. Similarly deformed beds appear characteristic of falling stage deposits in many sequences but they are perhaps best developed in M6C. UPPER ORDOVICIAN (CINCINNATIAN) SERIES Tippecanoe (Creek) Megasequence C1 to C7. Upper Ordovician: Cincinnatian Series The Upper Ordovician Cincinnatian (upper Katian: Caradoc and Ashgill) strata exposed along the western flank of the Cincinnati Arch comprise mixed shales, minor siltstones, shelly limestones and argillaceous dolostones. These strata have a complex terminology (Fig. 15); they are famed for their invertebrate fossil content, including diverse and spectacularly preserved corals, bryozoans, brachiopods, mollusks, trilobites and echinoderms (Meyer and Davis, 2009), which constitute a major component of the sedimentary rocks. Although reefs, per se, are minimally developed, biostromes are well developed at several levels, and time-averaged shell beds are exceptionally well represented in much of the succession. The Cincinnatian strata have been divided into seven third-order depositional sequences, referred to as C1-C3, by Holland and Patzkowsky (1993). In several instances these units can be further subdivided into distinct depositional sequences, which are herein temporarily labeled with A, B, C… designations, pending reconsideration of sequence nomenclature. Sequence C1. Point Pleasant-Kope Formation (Clays Ferry Formation) Sequence C1 (uppermost Chatfieldian-Cincinnatian; Caradoc or mid Katian) is represented by the Point Pleasant Limestone 5 to 10 m of skeletal grainstone and packstone and minor gray shale, and the shale dominated Kope Formation and laterally-equivalent upper part of Clays Ferry Formation. The overall sequence architecture of C1 is similar to that of the underlying M5 and M6 sequences, although the proportion of shale and siliciclastic silt is greatly increased. The Point Pleasant limestone has recently been studied and correlated in detail by McLaughlin and Brett (2007) who interpreted this skeletal carbonate as the LST-TST of sequence C1. The Point Pleasant rests sharply upon “pinstriped” (tidally laminated?) fine- to medium-grained calcarenites assigned by McLaughlin and Brett to the Locust Creek member and interpreted as the falling stage systems tract of subjacent sequence M6B. The grainstone-rich Point Pleasant member of the Lexington Limestone and the Fulton submember of the Kope Formation are designated as the TST of the C1 sequence. The thin (1-3 cm), but widespread pyrite- and conodont-rich Duck Creek bed at the top of the Fulton is designated as the maximum starvation surface. The overlying Kope Formation consists of up to 80 meters of medium to dark gray shale and thin bedded brachiopod, bryozoan and crinoidal pack- to grainstone; this interval has been subdivided into a series of six submembers on the basis of clustered limestones alternating with distinct intervals of thicker shale: “Big Shales” (Brett et al., 2003, 2008); these are, in ascending order, the Brent, Pioneer Valley, Snag Creek, Grand View, Grand Avenue, and Taylor Mill submemers (Brett and Algeo, 2001). These units and their component meter-scale limestone –shale cycles (numbered 1-40 following Holland et al., 1997), have proved to be widely traceable and they are interpreted as fourth-order cycles by Brett et al. (2003, 2008 and in this volume). Fossils provide an additional key to correlation. For example, the brachiopod Sowerbyella rugosa is particularly typical of the lower portion of the Kope, being especially common in the Brent and Pioneer Valley submembers.

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Figure 15. Generalized stratigraphic column of Upper Ordovician Lexington, and lower Cincinnatian strata, showing subsurface gamma ray profile, lithologic log, and faunal content. Abbreviations include: H-G: Hooke Gillespie submember, LBG: Lawrenceburg submember; LHQ: lower Hill Quarry beds, UHQ: upper Hill Quarry beds. Courtesy of B. Datillo.

The Kope shows distinct meter- and decameter-scale cyclicity (Tobin, 1982; Tobin and Pryor, 1981; Jennette and Pryor, 1993; Miller et al. 1997, 2001; Holland et al., 2000, Brett et al., 2003; Dattilo et al., 2008) has been extensively studied in terms of depositional environments and paleoecology, particularly gradient analysis (Holland et al., 2001; Miller et al., 2001; Brett et al., in this volume). The soft Kope shales have been eroded to form the steep hills and valleys of the Outer Bluegrass (Eden) region surrounding Cincinnati and in northern Kentucky. The shale-rich lower-middle Kope Formation is designated as a complex HST; however, the Kope actually may represent two third order cycles with the cluster of limestones referred to as Grand Avenue submember representing a second third order transgressive systems tract of C1B. A lower, more massive division of the Garrard Siltstone Formation in the Lexington platform area may record the falling stage (FSST) associated with the pre-Grand Avenue sea level drop in C1A. The overlying shale and siltstone-dominated upper Kope, Taylor Mill submember and laterally equivalent upper Garrard Siltstone are interpreted as the later HST to FSST of this sequence. Sequences C2 and C3: Fairview (Calloway Creek) and Grant Lake Formations Maysvillian age strata are represented by the Fairview Limestone and its lateral equivalent, the Calloway Creek Formation, in central Kentucky, and the McMillan Formation in Ohio and its lateral equivalents, the Grant Lake and Ashlock Formations in Kentucky. The lower interval (Fairview-Calloway Creek) is typified by bryozoan- and Rafinesquina-dominated brachiopod packstones, commonly with edgewise-brachiopod coquinas interbedded with thin shales and siltstones. The upper Miamitown Member is well developed in southern Ohio and southeastern Indiana (Holland, 1993; Holland et al., 2001; Holland and Patzkowsky, 2007; Fig. 15). These strata were originally assigned to Sequences C2 and C3 by Holland and Patzkowsky (1993); however, the lithostratigraphy of these Maysvillian strata and their sequence stratigraphyhave been recently thoroughly revised by Schramm (2011), who subdivided this succession into three third-order sequences. The first sequence includes the lower portion of the Fairview Formation and it is construed as having an LST/TST comprised of compact

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skeletal limestones (“Z” bed, North Bend submember of Mt. Hope Member) and a shaly, silty highstand; Wesselman and Reidlin submembers. Schramm (2011) interpreted the upper package of the Fairmont Member, and the overlying Miamitown Shale as parts of a second third-order sequence. Compact limestones at the base, informally termed Lawrenceburg submember, form the early TST, interbedded tabular limestones and shales formerly termed “Hill Quarry beds” were considered to represent a third order late TST to HST and the Miamitown was interpreted as FSST deposits. The McMillan or Grant Lake Formation in the Cincinnati region consists of thin, wavy nodular, bedded fossil fragmental limestones and minor shales of the Bellevue Member (Fig. 16). shales and thin-bedded brachiopod packstones of the Coryville Member (HST), and thin-bedded nodular pack- and grainstones of the Mt. Auburn Member (Terrill; TST). The upper, Mt. Auburn Member, is herein reinterpreted as the TST of sequence C4 (see below). Both the Bellevue and Mt. Auburn members are charactrized by large robust specimens of the brachiopod Vinlandostrophia (formerly Platystrophia) ponderosa. The laterally equivalent Grant Lake Formation in northern Kentucky includes a) locally well-developed cross-bedded crinoidal grainstones at the base overlain by b) thin-bedded, nodular packstones replete with V. ponderosa and Hebertella recognized as the lateral equivalents of Bellevue (TST) and Coryville (HST), respectively. In the southern Cincinnati Arch region, the Bellevue appears to pass laterally into pale greenish gray, laminated and rarely mudcracked dolosiltites of the Tate Member of Ashlock Formation, interpreted as a peritidal facies. This unit shows a retrogradation into nodular, shaly and brachiopod-rich facies, assigned to the Gilbert (or “Grant Lake” in a narrow sense) Member of the Ashlock and the latter locally passes upward into distinctively rhythmic, tabular bedded pale gray micritic wackestones and alternating dark gray shales, referred to as Stingy Creek Member.

Figure 16. Upper Fairview-Bellevue interval near Sherburne, Kentucky along Rt. 68.

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Sequences C4 to C6: Arnheim, Waynesville, Liberty and Whitewater Formations/Bull Fork and Drakes Formations The Richmondian Stage of the Cincinnatian Series commences with gray, silty shales and thin limestones termed Arnheim, Waynesville, Liberty, and Whitewater formations in Ohio (typically assigned to the Bull Fork and the Rowland Member of the Drakes Formation in Kentucky) consist of medium gray, brownish-weathering shale and brachiopod packstones. Sequence C4 Arnheim Formation Holland and Patzkowsky (1993) assigned a single unit, the Arnheim Formation, to sequence C4. However, reconsideration of the stratigraphy by Schramm (2011) indicates that the sequence should include both the Arnheim and the underlying Mt. Auburn Member and its equivlents. The Mt. Auburn near Cincinnati is a series of rubbly nodular to concretionary packstones rich in small phosphatic granules and containing an abundance of the brachiopod Vinlandostrophia ponderosa auburnensis as well as cephalopods and other mollusks. Farther to the southeast this interval contains at lest two small-scale cycles with grainstones alternating with nodular, shale biostromal wackestones; these beds locally yield abundant solenoporids and large, typically vuggy stromatoporoids. Still father to the south, these beds give way to pale olive gray laminate and desiccation cracked Terrill Member; highly analogous to the older Tate, the Terrill is interpreted as deposit of shallow lagoon to tidal flat environments. The Mt. Auburn and its equivalents form the lowstand to transgressive systems tract of sequence C4 as redefined herein. The Arnheim (Ohio) or lower Bull Fork (Kentucky) Formation comprises 21-30 m (70-100’) of interbedded medium dark greenish gray shale and skeletal pack- and grainstone that passes upward into nodular calcisitites and calcareous shale (Oregonian Member). The Arnheim is interpreted herein as the highstand systems tract of sequence C-4, the TST of which is represented by the Mount Auburn Formation. The lower Arnheim, Sunset Member and laterally equivalent Reba Member, shows the first incursion of several typical Richmondian taxa, including Leptaena richmondensis and Rhynchotrema dentatum, and Hiscobecus capax (see Holland and Patzkowsky, 2007). Its upper portion (Oregonia Member in Ohio) is a nodular argillaceous limestone and shale that contains abundant bryozoans, including Constellaria and Hallopora subnodosa. Sequences C 5A-C Holland (1993) originally assigned the entire Drakes Formation of Kentucky (Waynesville, Liberty, Whitewater and Saluda formations in Indiana and Ohio) into a single depositional sequence, C-5. However, recent work suggests that this succession is more complex and divisible into at least four sequence-motif units, corresponding to the a) Rowland (Waynesville, in part), b) Bardstown (Liberty-lower Whitewater), c) lower Saluda, and d) upper Saluda members. We herein term these divisions sequences C 5A, B, C, and D. Sequence C5A. Waynesville Formation-Rowland Member. The Waynesville Formation is complex and has been divided into three members in Ohio and Indiana: The Fort Ancient Member, most similar in aspect to the Kope Formation, is divisible into two cycles, each with a thick interval of soft clay shale (“butter shale” of collectors), separated by a thin cluster of limestones typically rich in the brachiopod Dalmanella meeki. The upper Fort Ancient “butter shale” termed the Treptoceras duseri shale by Frey (1987, 1988) in recognition of the abundance of this nautiloid cephalopod, is exceptionally rich in articulated trilobites Flexicalymene meeki and Isotelus sp. The middle Clarksville Member consists mainly of rather closely stacked pack- and grainstone beds exceedingly rich in Dalmanella (Frey, 1997); this may represent another third or fourth order transgressive package. Finally, the upper Blanchester Member, again is divisible into two more “butter intervals, similarly rich in articulated trilobites, separated by a limestone bundle rich in Rafinesquina, Strophomena, and other brachiopods. The

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limestone-rich bundle is overlain by a relatively thick shale interval. These are thought to be of approximately the same order of magnitude as the submembers of the Kope Formation. These subdivisions of the Waynesville appear to be traceable from northern Kentucky and southern Indiana, on the western side of the Cincinnati Arch, through south central Ohio (e.g. the well known outcrops at Caesar Creek in the Waynesville type area) and eastward to the MaysvilleFlemingsburg region of Kentucky, where they are mapped as parts of the Bull Fork Formation. To the south, the differentiation of the Waynesville members and submembers is less clearcut, as the interval passes into sparsely fossiliferous, calcareous to dolomitic mudstones and argillaceous wackestones dolostones of the lower Drakes Formation, Rowland Member. Ongoing research is attempting to recognize the major cycles. Present results suggest that the Rowland corresponds a shallow water succession between the lower and upper Marble Hill beds. This interval expands rapidly from a few meters near Bedford, Kentucky (type area of Marble Hill) to about 9-12 m of muddy limestone and mudstone about 20 km to the south. The latter interval persists with little thickness change to the south. South of Louisville this interval shows small-scale ripples, microbial lamination, and desiccation cracks, confirming a shallow, peritidal depositional environment. It is interpretated as a major (3rd order) TST. The base of the Waynesville Formation, though subtle and poorly exposed in the northern study area is an important sequence boundary globally and it corresponds approximately to the CaradocAshgill boundary of earlier usage (Holland and Patzkowsky, 1996), although recent interpretations place this stage boundary lower and near the top of the local Maysvillian Stage instead (S. Bergstrom, pers. com., 2012). The Waynesville Formation, where typically developed in Indiana/Ohio, and laterally equivalent so-called upper Bull Fork Formation in Kentucky commences with a basal compact bed, possibly correlative with the so-called Fisherville “reef” (coral biostrome) and lower “Marble Hill” gastropod-rich grainstone bed, up to 5 m thick, in northern Kentucky, which separates the Rowland Member from the underlying Bull Fork Formation in northern Kentucky. This bed, by itself, is considered to represent a TST by Holland (2009). More important, a major and previously unrecognized unconformity beneath the Rowland Member, correlative with the basal Marble Hill unconformity, appears to truncate the underlying Bull Fork units, possibly including the lower Waynesville Fort Ancient Member, and much of the underlying Arnheim-equivalent strata, until the Rowland rests on upper Maysvillian strata near Richmond, Kentucky. The middle-upper Waynesville (and laterally equivalent upper “Bull Fork”) fauna records a first return of many coral genera following prolonged outage of perhaps 5-6 million years in the late Chatfieldian to early Cincinnatian and may record a warming trend that ushered in the so-called Richmondian Invasion (Holland, 1997; Patzkowsky and Holland, 1993, 1996; Holland and Patzkowsky, 2007). Sequence C5B. Liberty –Whitewater Formation. The Liberty and lower Whitewater formations of Indiana and Ohio (Peterson et al., 1971; Peterson, 1981) consists of 11-15 m (35-50’) of fossiliferous packstones, grainstones, and mudstone, and, together, record a second third order sequence, here termed C5B. Locally, the base of the Liberty (or Bardstown member in Kentucky) is marked by a biostrome rich in both solitary rugosans and south of Louisville by colonial corals such as Cyathophylloides and Tetradium. A zone rich in the rugose coral Grewingkia, recognized in the Maysville area may correspond to the lower Bardstown or Otter Creek coral bed at the base of the Liberty Formation (or Bardstown Member of the Drakes Formation) on the west side of the Cincinnati arch. The latter appears to pass laterally in northern Kentucky into the upper Marble Hill grainstone.

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The Liberty, and essentially equivalent Bardstown Member of the Drakes Formation in Kentucky, comprises densely packed, shaly limestone, rich in whole and fragmentary valves of brachiopods, such as the strophomenids Strophomena, Leptaena, Eochonetes (formerly Sowerbyella) and Rafinesquina, the orthids Hebertella, and Platystrophia (Vinlandostrophia?), and the rhynchonellid Hiscobeccus capax. Solitary rugose corals (Grewingkia, Streptelasma) are abundant in some beds. This diverse fauna records a strong phase of the Richmondian Invasion (Holland, 1997; Holland and Patzkowsky, 2007). These shell-rich beds give way to blocky dolomitic mudstones of the lower Whitewater Formation. The latter, though rich in trace fossils (Planolites, Chondrites), is sparse in shelly fauna but includes moderately common bivalves. A basal calcarenite and overlying coral Bardstown biostrome are interpreted as a TST, whereas overlying beds are dominantly HST and the blocky, silty mudstone near the top represents FSST deposits. Sequence C5C. Lower Saluda submember of Drakes Formation. Along the west side of the arch the lower Saluda Member (lower Whitewater Formation in Indiana, in part) is sharply set off from the underlying dolomitic mudstones by an surface interpreted as a sequence boundary (Fig.17). A distinct interval with bryozoan-rich dolostones, referred to as the “Buckner bed” for excellent exposures at Buckner, Kentucky, is overlain by two or more closely spaced colonial coral biostromes (“Madison reef”). These fossiliferous beds are interpreted as a later TST/condensed section of sequence C5C and these beds, in turn, are overlain by a widespread, thin dark shale and dolostone succession interpreted as the highstand deposits; the latter may be truncated by an overlying erosion surface. Recent fieldwork in the region of Richmond and Waco, Kentucky (Drowning Creek) has led to recognition of possible equivalents of the Buckner bed: a dolomitic bryozoan-rich unit, which lies beneath green-gray shales and mudstones assigned to the Preachersville Member (see below).

Figure 17. Bardstown-Saluda members (of Drakes Formation) contact interval at Buckner, KY.

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Sequence C5D. Upper Saluda submember. From near Madison, Indiana to the western flank of the Cincinnati Arch, the upper submember of the Saluda Member consists of massive, rhythmically- laminated, desiccation cracked, pale orangebuff weathering, argillaceous dolostones up to 12 m (30-35’) thick (Fig. 18). The sharp base of this unit is newly interpreted as a fourth large-scale sequence boundary and the somewhat more burrowed, massive and less laminated dolostone immediately above may record an initial TST. The thick laminites likely reflect an aggradational early highstand systems tract.

A)

B)

Figure 18. Mudcracks (A) and vertical burrows in laminated dolosiltite of the Saluda Formation at Buckner, KY.

The laminated dolostone facies of the Saluda does not persist to the east side of the Cincinnati Arch. However, facies of the uppermost 5 meters of Drakes Formation, observed near Berea, KY appear to record a transition from upper Saluda to greenish gray, fossiliferous, shaly facies typical generally assigned to the Preachersville Member. Here, sparsely fossiliferous Drakes shales appear to be interbedded with laminated, Saluda-like, dolostones. These beds appear to overlie a bryozoan-rich interval correlative with the Buckner bed and a newly discovered bed of small Tetradium corals at the top of this succession my represent the Madison biostrome. To the east and southeast these dolomitic mudstone facies pass into greenish gray shales with minor maroon intervals typical of the Preachersville Member; increasing amounts of red mudstone are observed to the north and northeast into northern Kentucky and southern Ohio as the Preachersville passes laterally into the major Queenston-Juniata red bed succession of the Appalachian foreland basin. Sequence C6. Hitz beds and Elkhorn. The Saluda Member is, in turn, sharply overlain by moderately fossiliferous limestones and dolostones, variably referred to as the upper Whitewater or Hitz beds, near Madison, Indiana and at locations near Louisville, Kentucky. Small thrombolitic mounds occur on the upper surface of the basal 30-40 cm bed. Fossils in higher units include ramose bryozoans, small brachiopods and a distinctive small mollusk fauna. This fossiliferous carbonate is interpreted as the TST of Holland’s (1993) C6 sequence. Overlying younger strata are nearly everywhere truncated but may be recorded in bright green shale seen in the base of New Point Quarry in Indiana. In addition, higher Ordovician strata are represented pale cream to purplish colored and micritic limestone with abundant edgewise Rafinesquina, which is exposed in knobs, up to 3m high, surrounded by Silurian Brassfield Formation in the base of the quarry at Napoleon, Indiana. These mounds are interpreted as sea stacks (Mikulic et al., 2012; see also description of Napoleon quarry herein). Such strata have been removed at the Cherokee Unconformity nearly everywhere else. Ongoing

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work is attempting to clarify the age and relationships of these highest Cincinnatian strata (P. McLaughlin, unpublished data; T. Schramm, personal comm.). SILURIAN PERIOD: TUTELO SUPERSEQUENCE Cherokee Unconformity The Cherokee Unconformity separates the Creek (lower Tippecanoe) and Tutelo (upper Tippecanoe) megasequences (Fig. 19). The Silurian strata are subdivisible into a series of unconformity bound sequences, which can be correlated with those previously recognized in the Appalachian Basin (Brett et al., 1998; Brett and Ray, 2005). Sequence S-I: Brassfield Formation Brassfield Formation forms the basal Silurian unit of early Llandovery (Rhuddanian to Aeronian) and rests unconformably on Ordovician strata—typically the Preachersville Member of the Drakes Formation or, in the western Cincinnati Arch, the Saluda Dolostone. The contact, representing the Cherokee Unconformity is typically nearly planar, but locally, in the Louisville area the basal Brassfield locally occupies pockets or cavities cut into underlying Saluda carbonates (Fig. 20); these pods represent erosional remants of Brassfield as sinkhole fillings and in some high areas on the contact, the Brassfield is completely absent. The Brassfield of southern Ohio and north central Kentucky has been studied in detail by Gordon and Ettensohn (1984) who subdivided the formation into five unis. In the Dayton area an even older unit, the Centerville consisting of light weathering silty dolostone underlies the lower Brassfield (Belfast Member); the age relationships of the enigmatic unit remain unresolved and it may even be Upper Ordovician. The Centerville is a name first used by Foerste (1931) for shale and argillaceous dolostone located below the Brassfield Formation at three localities where the Belfast was absent in western Ohio. At a large quarry half a mile northeast of Centerville it was 0.75 , (2.5’) of indurated clay, according to Foerste (1935). Foerste (1935) recognized the Centerville beneath the Belfast near Lawshe and south of West Union. At most locations the base of the Brassfield is formed by a distinctive 1-3m interval, the Belfast Member (Foerste, 1935), comprising a sharp based basal glauconitic, highly bioturbated sandy dolostone with scattered rugose corals and brachiopods; this bed passes upward into sandy shales. It has yielded conodonts of the D. kentuckyensis zone (Cooper, 1975), suggesting an early Llandovery age. Belfast appears to represent a small-scale (4th order) sequence. In most areas of the southern and eastern Cincinnati Arch outcrop belt the Belfast is sharply overlain by the “cherty” member of the Brassfield. This is a 1-3m interval comprising massive sparsely fossiliferous dolostone with several rhythmic pale gray to cream colored chert beds and thin glauconitic zones. The latter passes upward into “thin bedded” and “shaly” members of the Brassfield (Fig. 21). The latter includes gray to maroon shales alternating with thin beds packed with distinctive, large, cogwheel crinoid columnals (Floricolumnus). Recent work shows that these beds are widely traceable at least from Richmond, Kentucky north to Dayton and probably belonged to a distinctive large camerate crinoid with a distally coiled stem (J. Thomka unpublished data). Together, the massive cherty member and thin-bedded shaly members appear to represent the TST and HST, respectively of a second fourth order sequence. The age is debatable but probably ranges from late Rhuddanian to early Aeronian. Throughout much of the study area from the southern Cincinnati Arch north to Highland County, OH, the shaly member is abruptly overlain by the upper massive member, an interval ranging up to about 1.5 m thick of hematitic, crinoidal grainstone, informally termed Rose Run member; (Fig.

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21). Locally, this unit also is reported to contain Floricolumnus “beads” (see McLaughlin et al., 2008). This bed is treated herein as the basal TST of overlying sequence S-II (see below).

Figure 19. Generalized chronostratigraphy and carbon isotopic curve for the Silurian stratigraphic succesion in eastern North America. Note subdivision into unconformity bound 3rd order sequences. Colors indicate predominant shale colors. Note strong positive carbon isotopic excursions in the early Sheinwoodian (“Ireviken”), Homerian (“Mulde”) and Ludfordian (“Lau”). In the Dayton region and western Ohio the Brassfield above the Belfast bed comprises a lower massive, pale yellowish gray to white, cross bedded, crinoidal, and locally cherty lower division, a thin middle shaly zone and an upper reddish to greenish gray, argillaceous pack- grainstone with local bioherms (“red Brassfield”). The age relationships of these two units are debatable but some evidence suggests that the red Brassfield is substantially younger Aeronian age and rests unconformably on the lower Brassfield. It may be correlative to the Rose Run unit, rare bead-like columnals have been reported (McLaughlin et al., 2008); however, the presence of the brachiopod Microcardinalia, reported by Berry and Boucot (1970) near Dayton suggests that the red Brassfield, may correlate with the Oldham Formation (Sequence IIB; see below).

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Figure 20. Saluda-“golden” Brassfield-Lee Creek Member contacts at Crestwood, KY.

A)

B)

Figure 21. A) Upper massive (Rose Run) member of Brassfield overlying shaly member of Brassfield and B) possible herringbone cross bedding in crinoidal limestone of “shaly member”; Owingsville Manor, Owingsville, KY. In the Dayton region and western Ohio the Brassfield above the Belfast bed comprises a lower massive, pale yellowish gray to white, cross bedded, crinoidal, and locally cherty lower division, a thin middle shaly zone and an upper reddish to greenish gray, argillaceous pack- grainstone with local bioherms (“red Brassfield”). The age relationships of these two units are debatable but some evidence suggests that the red Brassfield is substantially younger Aeronian age and rests unconformably on the lower Brassfield. It may be correlative to the Rose Run unit, rare bead-like columnals have been reported (McLaughlin et al., 2008); however, the presence of the brachiopod Microcardinalia, reported by Berry and Boucot (1970) near Dayton suggests that the red Brassfield, may correlate with the Oldham Formation (Sequence IIB; see below). The Brassfield along the western flank of the Cincinnati Arch near Louisville is thin (typically less than 1 m) yellow-orange crinoidal grainstone with scattered small rugose corals, brachiopods and other fossils. Conodonts of the Distomodus kentuckyensis Zone, together with brachiopod evidence, indicate a Llandovery possibly Aeronian age; as such this unit may be a correlative of the

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“red Brassfield” of Ohio. The Brassfield carries a relatively diverse fauna of brachiopods, small corals and other invertebrates, originally described by Foerste (1931, 1935). S-II: Noland Formation Sequences S-II and S-III, the lower and middle portions of the Clinton Group, recognized in the Appalachian Basin are absent in the Louisville area although portions of these are recorded in the Crab Orchard Group (typically called Crab Orchard Formation in Kentucky) of central Kentucky and southern Ohio. In the southern and eastern Cincinnati Arch these sequences are well represented by the Noland Formation (of the Crab Orchard Group). As in the classic Clinton of west central New York, the Noland can be subdivided into two fourth order depositional sequences. In our interpretation (Brett and Ray 2005) the lower sequence actually comprises the so-called Rose Run member (technically upper massive member of Brassfield Formation; Gordon and Ettensohn, 1984) and the overlying the Plum Creek Member. Rose Run is a compact hematitic and phosphatic crinoidal carbonate with internal hardgrounds. Near Hillsboro, Ohio the Rose Run comprises nearly 2 meters of cross-bedded hematitic grainstone; at its type section, near Owingsville, Kentucky, the Rose Run was formerly mined as an iron ore. As recognized by Gordon and Ettensohn (1984), the base of this unit is an important regional unconformity, although the occurrence of the distinctive crinoid “beads” (Floricolumnus) both below and within this bed suggests that the hiatus at this surface may not be great. The Plum Creek Member comprises 2-3 m of dark bluish gray clay shale. The two units are interpreted as a condensed TST and shaly HST, respectively. They are tentatively correlated with the Densmore Creek phosphate bed and Maplewood Shale, sequence S-IIA, of western New York State (Brett et al., 1998; Brett and Ray, 2005). Sparse evidence from brachiopods Cryptothyrella subquadrata and conodonts suggest that these units are of early Aeronian age. Anita Harris in McDowell, R. C. (1983) identified a specimen recovered from the Lulbegrud as Pterospathodus pennatus (now recognized as Pt. eopennatus, nominal species of the eopennatus Zone). So it is possible that the Lulbegrud is of early Telychian. The Oldham Dolostone and Lulbegrud Shale, together comprise a second sequence correlated with S-IIB, the Reynales Limestone and Sodus Shale in the Appalachian Basin. The Oldham consists of three meter-scale shale-fossiliferous (rugose corals, Leptaena) limestone cycles, the upper of which contains the stricklandiid brachiopod Microcardinalia, which suggests a late Aeronian age. The Lulbegrud is largely barren greenish gray shale. The Oldham may correlate with reddish reefal beds presently termed red Brassfield in western Ohio. Sequence S-III. Waco Formation (new) and Lee Creek Member Although originally defined as the upper unit of the Noland Formation, the base of the Waco interval is disconformable on underlying units and we therefore prefer to separate this unit as a distinct formation. In central to northeastern areas of the Cincinnnati Arch, an additional sequence boundary is recorded in the sharp base of the Waco Formation, which appears to be a regionally angular unconformity (Lukasik, 1988). Traced northwestward in the outcrop belt, the Waco oversteps lower units in the Noland Formation; Near West Union, Ohio only a remnant of the Oldham and the Plum Creek occur below the basal Waco carbonates and further north near Hillsboro in Highland County the Waco rests on shaly upper Brassfield with all of the Noland Formation truncated.

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The Waco consists of a basal member, up to a meter thick of glauconite rich carbonates, typically a two-part succession with a basal pale greenish gray dolostone with abundant favositid corals, a thin middle shale and an upper orange weathering dolostone typically with a distinct Teichichnusburrowed firmground at its base. The upper Waco consists of greenish gray shale and thin dolomitic packstones that are locally richly fossilferous with abundant fenestrate bryozoans, rugose and small tabulate corals and large crinoid columns. The Waco in Ohio has commonly been misidentified as Dayton but recent conodont studies (Kleffner et al, 2012; Sullivan, unpublished) indicate that the Waco carbonates are a distinct, substantially older unit; samples from Highland County have yielded conodonts of the Pt. eopennatus Zone, and hence the Waco is of mid Telychian age, while the Dayton belongs to the Pt. amorphognathoides amorphognathoides Zone; its basal erosion surface may overstep the Waco in the Dayton area. The Waco is tentatively correlated with the Wolcott-Sauquoit succession (Sequence S-III) in central New York. Shales presently assigned to the base of Estill Shale near Jacksonville in Adams County are early Telychian, probably Pterospathodus amorphognathoides angulatus Zone (Kleffner, 2000). We suggest that these shales actually belong to the upper shale member of the Waco. Along the western side of the Cincinnati Arch a thin, orange weathering dolostone, the so-called Lee Creek Member of the Brassfield, consists of pale, slightly greenish, buff weathering, dense dolostone with dark streaks that may represent indistinct hardgrounds. This unit is present in only some localities and is set off from the underlying unit by a subtle but distinctly unconformable contact, an erosion surface with minor relief (Fig. 20). Conodont studies of Nicoll and Rexroad (1968) indicate that the Lee Creek Member is actually of late Llandovery (Telychian) age (eopennatus Zone of current usage) and thus is separated from underlying strata by a substantial unconformity at which much of the Llandovery is missing. Regional studies (Lukasik, 1988; Brett et al., 1990; McLaughlin et al., 2008a, b) indicate that its basal surface is coextensive with a regionally angular unconformity that bevels successively older Silurian units in a northwestward direction from near conformity in the Appalachian Basin. As such the Lee Creek may be correlative with the basal carbonate of the Waco Formation to the southeast. Sequence S-IV. Dayton-Estill and Osgood Formation In the western Cincinnati Arch region, near Dayton, Ohio, the Waco Formation appears to be missing in most localities or represented simply by remnants of the Lee Creek Member. Here a new and somewhat comparable glauconitic carbonate, the Dayton Formation overlies beds typically assigned to the Brassfield at a second regionally angular unconformity. The Dayton comprises 1 to 4 m of pale greenish gray, glauconitic dolostone or dolomitic limestone rich in glauconite and typically showing stacked, phosphate stained hardgrounds. Recent conodont studies of the Dayton Formation (Kleffner et al. 2012) suggest that it belongs to the Pt. amorphognathoides amorphognathoides Zone of the latest Telychian. The Dayton is considered to represent the TST of sequence IV. Toward the Appalachian basin in southern Ohio and central Kentucky the Dayton rapidly becomes argillaceous and appears to pass into a zone of abundant glauconite granules and a distinctly reddish shale band that have been used in Kentucky to recognize the base of the Estill Shale Member (Rexroad et al., 1965) at a cryptic contact upon shales of the Waco Member. Recent study has revealed abundant conodonts that may help to resolve the age of this unit (N. Sullivan, unpublished data). The Estill Shale (sensu stricto) is up to 20 m thick and comprises greenish gray to maroon often banded claystone with thin siltstones and minor shell hash beds, particularly in the informal upper or Ribolt member. The Llandovery/Wenlock boundary is low in the informal upper member (Ribolt) of the Estill Shale at Measley Ridge according to McLaughlin et al. (2008) and is within the Upper Pterospathodus Zonal Group and Lower K. ranuliformis Zone (M. Kleffner, personal communication). In western New York the Llandovery/Wenlock boundary is either between the

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Rockway and Irondequoit (Cramer et al., 2006) or in the basal Irondequoit (M. Kleffner, personal communication). The Ribolt member also yields the ostracode Mastigobolbina typus providing a tie with the latest Telychian-earliest Wenlock M. typus Zone including the Williamson-Rockway and uppermost Rose Hill formations of the Appalchian basin. Near Louisville Sequence IV is represented by the ~10 m (30’) thick Osgood Shale. In Indiana, the Osgood is referred to as a member of the Salamonie Dolostone; however, in Kentucky the same interval is referred to as the Osgood Formation and that practice is followed herein. The interval formerly assigned to “Osgood” in the broad sense, has been subdivided into informal members: the lower shaly, middle carbonate and upper shaly units. These are correlated with units previously recognized in the Dayton area of Ohio and treated as distinct formations herein, such that the term Osgood Formation is restricted to the former lower shaly member, the thickest division. This interval consists mainly of rhythmically interbedded, medium gray shale and argillaceous dolostone that weathers pale orange-buff (Fig. 22). Recent studies indicate that the specific pattern of rhythmic carbonate-shale beds are extremely widespread permitting very high resolution correlations of the Osgood and its correlatives from the Rockway of New York and Ontario to the so-called lower Maddox Formation in Tennessee (Brett et al., in press; Thomka et al. 2012, unpublished data). These correlations further imply that the rhythmic carbonate-shale beds are of primary origin and record basin-wide fluctuations in sediment supply, enhanced by diagenesis. Just south of Louisville the lower few meters of the Osgood show alternating maroon and olive gray colored clay shale (Fig. 23). This interval grades laterally into the thicker gray and maroon colored Estill Shale further south at Bardstown, KY.

I Figure 22. Rhythmic bedding in Osgood Formation, with cluster of four distinct marker beds; I-71 cut near Crestwood, KY.

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Figure 23. Basal Osgood Shale showing red and green color bands at Mt. Washington, KY.

The Osgood Shale has been dated by conodonts as belonging to the Upper Pterospathodus Zonal group and Kockelella ranuliformis Superzone (which includes both the Lower and Upper K. ranuliformis Zones), spanning latest Llandovery to early Wenlock. Many of the limestones show trace fossils, including Chondrites and Planolites but the Osgood is otherwise sparsely fossiliferous, owing, in part to dolomitization. Upper parts of the formation show occasional pelmatozoan ossicles and near Napoleon, and Osgood, Indiana, where the unit is less strongly dolomitic, the Osgood Shale carries a moderately diverse fauna of brachiopods (Atrypa, Eospirifer, Leptaena, Coolinia), small bryozoans and echinoderms, of which the minute disparid crinoid Pisocrinus is particularly typical (Frest et al., 1999). This rather generalized fauna of the Osgood carries distinct elements not present in earlier Silurian and suggests incursion of faunal elements associated with a major highstand, which linked formerly isolated biogeographic regions. The Dayton and Osgood/Estill Shale are interpreted to represent, respectively, condensed TST, and somewhat more expanded, shaly HST of late Telychian-earliest Wenlock depositional sequence SIVB. This sequence is correlative with the Rockway succession in the Appalachian Basin. The basal unconformity with underlying strata records one of the largest transgression of the Silurian and it is associated with the onset of a major bioevent (Ireviken Event) and evidence for disturbance in the global carbon cycle as reflected in a major positive carbon isotopic excursion (also sometimes termed the “Ireviken excursion”, Cramer et al., 2006a). Sequence S-V. Bisher Formation; Lewisburg Limestone- Massie Shale In the southern and southeastern Cincinnati Arch, units above the Estill Shale have been removed by erosion, presumably at the Devonian Wallbridge and subsequent, superimposed unconformities, such that in places a 50 to 60 million-year unconformity exists between Famennian Ohio Shale and Telychian Estill Shale. Absence of higher Silurian units appears to reflect a regional arch in this area, possibly the precursor of the Waverly Arch. Possible erosional remnants of the Bisher Dolostone have been reported near Irvine, KY. These erosional remnants indicate that development of this positive feature post-dated Wenlock deposition though there is evidence that deposits of this age record shallower facies than those to the east or west of axis approximately connecting Herrin Hill, Ohio with Portsmouth, Ohio. 32

To the northeast, along the eastern rim of the Cincinnati Arch, in northeastern Kentucky and southern Ohio, the Bisher Formation, a typically thick bedded to massive or locally shaly dolostone, is inserted below the Silurian-Devonian systemic boundary. The Bisher Formation is a heterolithic unit that actually represents the dolomitized equivalents of several distinctive intervals. The basal 1 to 4 m of Bisher Formation has been termed the “ Cryptothyrella (Meristina) cylindrica bed” of central Ohio because of an abundance of the brachiopod Meristina cylindrica (formerly Cryptothyrella; Boucot in Rexroad et al., 1965). The basal Bisher at Measley Ridge is within the Upper K. ranuliformis Zone and samples from just 1 m above the base are within the Ozarkodina sagitta rhenana Zone. At both Herrin Hill, Kentucky and Measley Ridge, Ohio, this interval comprises a sharply based lower bed of brachiopod-bearing dolostone, a middle crinoidal limestone, rich in brachiopods and an upper calcareous siltstone interval with lenses of abundant brachiopods. Locally these beds contain a rich fauna including the nominal M. cylindrica, atrypid brachiopods, Striispirifer niagarensis, Coolinia and others strongly reminiscent of the fauna of the Irondequoit and lower Rochester formations in the Niagara region of New York. As with those units, the C. cylindrica Beds represent the transgressive systems tract of sequence S-V. In Highland County, Ohio the M. cylindrica bed is overlain by a distinctive shale and platy, argillaceous dolostone herein informally termed “shaly member” that is interpreted as highstand mudstones correlative with the Rochester Shale in New York (Brett and Ray, 2005); this correlation is corroborated by macrofaunal evidence (e.g. occurrence of Striispirifer niagarensis) and the occurrence of O. s. rhenana Zone conodonts at several locations in the shaly member (Kleffner in McLaughlin et al., 2008). At Measley Ridge the upper Bisher, also belonging to the rhenana Zone, comprises a thick succession of hummocky to swaley cross-stratified dolograinstones with zones of deformation. McLaughlin et al. (2008) interpreted this interval as an expanded highstand-falling stage, perhaps equivalent to the DeCew Dolostone at the top of Sequence V in the Appalachian Basin; this unusual facies may also reflect the shallow position of a local arch or positive area on the seafloor. In the western Cincinnati Arch the (lower) Osgood Shale is overlain by a thin, compact dolostone and dolomitic limestone, formerly termed “upper Osgood carbonate member” and even “Laurel Dolomite” in Ohio (McLaughlin et al., 2008; Brett et al., 2012; because of these terminological ambiguities this carbonate was reassigned to the informal “Lewisburg dolostone bed” by Kovach (1974; McLaughlin et al., 2008) The term is now formalized by Brett et al. (2012) (Fig. 24). Although the original fabric is largely altered by diagenesis, weathered surfaces indicate a pelmatozoan packstone to grainstone. Brachiopods, especially Atrypa, Meristina, and Whitfieldella are locally common. Near the top, small bioherms, apparently of algal/microbial boundstone and fistuliporoid bryozoans may extend upward from slightly below the Lewisburg contact into the overlying shale for up to 0.5 m and demonstrate the conformable nature of this contact. This limestone shows many similarities with the basal Bisher Formation “M. cylindrica bed” of central Ohio and with its apparent correlatives, the Irondequoit and Keefer Formations in the Appalachian basin, all of which contain an abundance of the nominal brachiopod Meristina cylindrica, which does not occur higher than the lower Rochester Shale in the Appalachian Basin. This would imply a Kockelella ranuliformis Zonal age for all of these units (Rexroad, 1980; Rexroad and Kleffner, 1984). However, the presence of the conodont Kockelella walliseri in the base of the Lewisburg dolostone is problematic (McLaughlin et al., 2008; Kleffner et al. 2012). This conodont has proven to appear diachronously in Gotland with respect to the Appalachian

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Basin (Cramer et al., 2011) and thus we suggest that its occurrence in the Lewisburg bed should be weighed against other evidence that indicates an older age assignment.

A)

B)

Figure 24. Lewisburg Dolostone overlain by Massie Shale and Laurel Formation. Closeup of the lower part of the Massie Shale sharply overlain by upper unit. Note thin carbonate beds in Massie Shale.

The 0.5 to 1.5 m Massie interval, formerly termed upper shaly member of the Osgood Formation (Fig. 24), is coextensive with a lithologically identical, dark gray shale, termed Massie Shale, in western Ohio from at least the Yellow Springs-Dayton area to the Indiana State line. The name Massie is extended into Indiana and Kentucky. Although this shale is locally strongly dolomitic, a few areas (e.g., Osgood and Napoleon, Indiana show unaltered facies that are richly fossiliferous (Brett et al., 2012) and these fossil assemblages show much in common, not only with the “upper Osgood Shale” of Indiana and with the shaly member of the Bisher to the southeast; the faunas of the Massie/”upper Osgood” have already been shown to share many unique taxa with the Rochester Shale of New York State and Ontario (Bassler, 1906, Tillman, 1964; Frest et al., 1999). Brett et al. (2012) also recognize an upper member within the Massie, which was previously mapped as part of the Laurel Formation. The latter is a massive unit with two informal divisions. The basal unit is tabular bedded dolomudstone or dolowackestone. Furthermore, recent work strongly suggests that the Massie is coextensive with the middle shaly member of the Bisher; however, this interpretation is at odds with the occurrence of K. walliseri in the Massie Shale. This would suggest an age for the Massie substantially younger than the shaly member of the Bisher, which is dated as O. s. rhenana (see discussion of Lewisburg bed, above). Ongoing work is directed at resolving this conflict. Sequence S-VI. Lilley Formation/Laurel Dolostone The Bisher is overlain by dolomitic grainstones and argillaceous dolostone and shales assigned in southwestern Ohio to the Lilley Formation. This interval actually shows two fourth order sequences, probably correlative with the Gasport and Goat Island formations of the Lockport Group in New York. The basal cross-bedded grainstone rests sharply on shaly upper Bisher beds and represents the Sequence VIA boundary: the base of the Lockport Group in Ontario and New York. A middle argillaceous zone, locally with small bioherms, represents the highstand. The upper Lilley likewise consists of a lower dolograinstone and an upper very shaly interval. A series of bioherms up to 2 m high extend upward from the contact into the overlying shale. The massive grainstone and shaly Lilley are tentatively correlated with the Goat Island and Vinemount Shale units of the Lockport Group. Correlation with the western Cincinnati Arch, however, has proved more controversial.

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Across a relatively narrow interval along the outcrop belt in Ohio, roughly from Leesburg northwest to Cedarville, there appear are relatively abrupt facies changes and very few outcrops, which make correlation of the Lilley with units in Greene County near Dayton somewhat problematical but regional detailed tracing of units strongly suggests that units of the Lilley can be matched with the Euphemia and Springfield (see below). Conversely, correlation of the units overlying the Massie Shale from Greene County and western Ohio into Indiana is relatively straightforward. The basal Laurel comprises a massive, vuggy dolostone termed Euphemia whereas the middle and upper Laurel consists of tabular bedded (“building stone beds”) lithofacies resembling the typical Springfield Dolostone of western Ohio. A sharp, and apparently erosive, contact separates the Massie Shale from the overlying 9-12 m (3040’) Laurel Dolostone (Fig. 25). The basal unit comprises massive vuggy dolostone, originally fine-grained grainstones and wackestones with layers of chert nodules that locally passes into limestone. Fossils are scarce at most sites, probably owing to diagenetic destruction, but in the vicinity of St. Paul, Indiana, where the Laurel is only slightly dolomitized, this interval yields a highly diverse and unique echinoderm fauna with over 60 species of crinoids, including many unique genera (Frest et al., 1999); brachiopods, bryozoans and corals are suprisingly infrequent. This interval may be coeval with the Euphemia Dolostone of Ohio (McLaughlin et al., 2008). The second unit is more tabular, medium-bedded, pale buff dolostone with a fine-grained sucrosic texture and white chert bands. This interval is sparsely fossiliferous, but yields articulated Gravicalymene trilobites. The distinctive lithological and taphonomic characteristics of this unit closely resemble those of the Springfield Dolostone of Ohio (Kleffner et al., 2012).

A)

B)

Figure 25. Laurel Dolostone displaying (A) basal tabular, middle vuggy (Euphemia Dolostone equivalent), and (B) upper tabular (Springfield Dolostone equivalent) informal divisions at a roadcut on the southwest side of Louisville.

Sequence S-VII. Limberlost oolite, Waldron Shale, Lower Louisville Formation The top of the Laurel islocally developed on a thin oolitic dolostone. Large favositid corals occur in this level, which is benched at Sellersburg Quarry. It is interpreted as a maximum starvation surface. In areas of the western Cincinnati Arch, the Laurel Formation proper is sharply if cryptically overlain by a very thin distinctive oolitic dolostone unit, ranging from millimeters to a few centimeters thick; this interval is correlated with the Limberlost Member (of Salamonie Dolomite). It appears to represent a basal transgressive lag deposit and passes gradationally upward into calcareous Waldron Shale; the latter contains very thin lenses of oolitic dolostone in its basal beds in some locations Elsewhere, the contact with the overlying Waldron Shale is abrupt and is

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developed as an encrusted hardground at the Waldron type section (Halleck, 1973), although it is obscured by “welded” overlying dolomudstone at Sellersburg. The Waldron Shale ranging from 1.2 to 4 m (4-13’) is a medium dark gray to greenish gray mudstone and argillaceous limestone. The Waldron Shale at Newsom Station, Tennessee yielded distinctive double peaks of positive δ13Ccarbonate values, which Cramer et al. (2005) identified as the Mulde excursion, previously documented in Gotland and elsewhere. Recent, isotopic studies have demonstrated a similar pattern in the Waldron of northern Kentucky (B. Cramer, pers com., 2009), confirming other paleontological and sequence stratigraphic evidence for the isochronous nature of the Waldron Shale over this region. Waldron Shale ranges from essentially barren to highly fossiliferous and the unit can vary between these extremes over relatively short distances (Feldmann, 1989). The rich fauna, where present, is typically highly diverse and includes more than 25 species of brachiopods, small rugose and favositid corals, fistuliporoid, fenestrate and ramose trepostome bryozoans, gastropods, small bivalves, trilobites and crinoids and other echinoderms. The Waldron has been famed as a source of exceptionally preserved Silurian fossils since its initial documentation by Hall (1879, 1882). Small micritic, fistuliporoid bryozoan bioherms occur locally up to about a meter above the base of the Waldron (Fig. 26). A second set of bioherms occurs in the upper meter of the Waldron, typically in small channel fills, which are lined with coarse skeletal rudstone or grainstone. A second set of bioherms occurs in the upper meter of the Waldron, typically resting upon grainstone lenses a few 10s of centimeters thick and a few meters wide that may represent small channel fills. Certain beds yield exceptionally well-preserved fossils including articulated trilobites and complete crinoid crowns; these have provided important insights into tiering and paleoecology (Peters and Bork, 1998, 1999; Watkins and McGee, 1998). These fossils indicate that Waldron muds accumulated in episodic pulses either owing to resuspension of muds during storms or because of offshore-directed mud plumes derived from strong flooding of coastal source areas.

A)

B)

Figure 26. A) Irregular beds mark the position of a bioherm within the Louisville Limestone (center of image) resting above a bioherm in the upper Waldron Shale at Stop 4. B) Profile of the argillaceous Wabash Formation and its contact with the Devonian at Atkins Quarry, Jeffersonville, Indiana.

The Waldron greenish gray mudstones are commonly very rich in euhedral pyrtic, which occurs as minor burrow fill replacements, as small nodules and as crusts on many fossils. The large cubic crystals as opposed to framboidal fine-grained pyrite point to a later diagenetic origin. Evidently

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sulfate reduction commenced at substantial depth within the Waldron muds (fossils are rarely if ever in-filled with pyrite framboids) and was followed by prolonged growth of pyrite crystals, which seem commonly to have nucleated on calcitic skeletons. Another intriguing feature of Waldron taphonomy is the tendency of enclosed, articulated brachiopods, and crinoids to occur as uncrushed, calcite-spar filled skeletons. The robust preservation of these fossils points to very early diagenesis of calcite fills within the enclosures of rapidly buried skeletal remains. The calcite diagenesis in this case appears to have predated pyritization and obviously occurred in the upper zones of the sediment. Sequence S-VIII? Peebles, Cedarville, Louisville and Wabash Formations In southern Ohio shaly beds of the Lilley Formation are abruptly overlain by massive vuggy dolostone containing lenses replete with pentamerid brachiopods. This interval, up to 20 m thick is identified as the Peebles Dolostone. Northwest of the critical zone of rapid transition the Peebles as such is not reported and, instead, another massive locally pentamerid-bearing dolostone referred to as the Cedarville occurs at the top of the Silurian succession. The Cedarville is locally highly fossiliferous and contains poorly preserved corals, crinoids, cystoids, and nautiloids and locally gastropods and megalomid bivalves typical of the Guelph fauna. The relationships of the Peebles with Cedarville Dolostone remain to be investigated. McLaughlin and Brett (in McLaughlin et al. 2008) suggest that Peebles and Cedarville are correlative facies and that the latter is equivalent to the Louisville of Indiana. Conversely, Cramer and Kleffner argue on the basis of similar carbon isotope patterns that the Waldron-Louisville succession is laterally equivalent to the Greenfield of Ohio. For the present, the issue remains unresolved and it will not be further investigated on this trip. On the western side of the Cincinnati Arch the Waldron Shale is overlain by the Louisville Formation Louisville varies from medium bedded to massive light gray wackestones, packstones, and grainstones. The basal beds are fossiliferous wackestones and packstones. The Louisville and adjacent units have recently been documented in considerable detail from the Atkins Quarry by Conkin (2002). The basal 3-4 m of the Louisville, assigned to the “Big Rock member” by Conkin (2002) is argillaceous, crinoidal, locally cherty dolostone which is divided into about three packages (cycles) by thin but prominent shale seams. Bioherms are locally present in the lower 2-3 m (Anderson, 1980). An interval of about 2 m of massive skeletal packstone, rich in pentamerid brachiopods (Conchidium?) is present about 3 m above the base of the Louisville. Silicified small pentamerids and rugose corals may dissolve out freely from this zone in strongly weathered outcrops. Although, this interval is assigned to the middle Big Rock member by Conkin, the sharp basal contact of the pentamerid limestone may represent a minor sequence boundary and the shell hash concentrates a TST. The overlying beds of this member consist of a series of rather even, medium bedded, medium to dark tan limestone beds, which were given names by quarrymen (“Granddad”, “Great Granddad” and “Three Foot” ledges, each about 30-40 cm thick. The lower of these beds is fossiliferous and contains small corals, The uppermost 3 m of the Big Rock Member is somewhat thicker bedded, and is glauconitic and pyritic somewhat fossiliferous wacke- to packstone containing abundant colonial rugosans such as Arachnophyllum. These beds may reflect highstand carbonate deposition.

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Higher beds in the Louisville, assigned by Conkin to the Shanks Quarry Member are flaggy (base) to very thick, bioturbated olive gray to bluish gray, sparsely fossiliferous dolostones (with names again reflecting their former use as curbing and paving stones because of a tendency to break into distinctive blocks: “Paving ledge”, “Blue Captain”, and “22 Inch ledge”). These facies are difficult to interpret because of the nearly complete absence of body fossils and sedimentary structures. They may reflect shallow burrowed lagoonal muds associated with regression. Dating of the Louisville is poorly constrained and recent attempts to extract conodonts from the unit have yielded no diagnostic taxa, but the presence of the pentamerids Rhipidium, as well as Kirkidium suggests an age of late Wenlock to early Ludlow (Berry and Boucot, 1970; Rexroad et al., 1978). The Wabash Formation, locally removed by erosion at the Wallbridge unconformity in the Louisville area, is about 5 m thick at Sellersburg, Indiana. It consists of alternating pale buff gray, argillaceous, blocky dolostones which carry only very sparse body fossils and burrows, alternating with light gray limestones with wacke- to packstone fabrics that contain abundant thin laminar stromatoporoids, favositid and halysitid tabluates, heliolitids, crinoid debris, brachiopods and other fossils. These beds typically contain alternating thin bands of bluish gray to cream-colored chert. A thin K-bentonite near the base of the Wabash Formation has yielded zircons, which are being processed for U/Pb dating. An early Ludlow age assignment of the Wabash is somewhat constrained by the occurrence of the brachiopod Kirkidium and the graptoloid Monograptus bohemicus in the (lower) Mississinewa Shale Member in northern Indiana (Berry and Boucot, 1970). In Ohio, the Upper Silurian Greenfield Dolostone, a peritidal to shallow subtidal unit, rests unconformably above the Cedarville and Peebles dolostones. We tentatively suggest that disconformity is coextensive with the Salina unconformity in the northern Appalachian Basin. The Greenfield, and overlying Tymochtee and Maumee formations of northern Ohio are presently under study but are beyond the scope of this paper. KASKASKIA SUPERSEQUENCE Louisville Paraconformity The Louisville Paraconformity is a local manifestation of the widespread Wallbridge Disconformity that defines the boundary between Sloss’s upper Tippecanoe (Tutelo) and Kaskaskia megasequences. In the vicinity of Louisville this disconformity is typically a planar surface separating underlying Silurian units (Wabash or Louisville Formations) from the overlying Middle Devonian Jeffersonville Limestone (Fig. 27). Given the estimated a late Wenlock to early Ludlow age (424 to 422 my) for underlying Silurian units and a relatively well established age of about 392 for the early Eifelian Jeffersonville Limestone, the magnitude of this unconformity is about 30 million years. During this interval the North American craton was largely exposed to karstification and erosion. Despite this magnitude of time and process the unconformity surface is nearly planar and reveals little evidence of erosion; indeed it is the classic example of a paraconformity: a cryptic disconformity. Fossiliferous limestones with abundant corals typically both underlie and overlie the unconformity making it difficult to locate in some outcrops. Those below are typically pale gray and contain a variety of Silurian corals including Halysites; the Jeffersonville basal beds are rather similar, but pinkish gray crinoidal pack- to grainstones with abundant substantially larger favositids and abundant rugose corals.

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A)

B)

Figure 27. A) The Louisville Paraconformity (at the hammer) contact between the Louisville and Jeffersonville formations in the Sellersburg Quarry, Indiana. B) Close-up of contact.

MIDDLE DEVONIAN SERIES Kaskaskia Megasequence: In Indiana the Silurian is unconformably overlain by the Jeffersonville Formation comprises some 11 m of fossiliferous limestone, primarily pack and grainstone with minor chert. These beds are exceptionally well exposed at the Falls of the Ohio in Clarksville Indiana and adjacent Louisville, KY. North of the Louisville area the Jeffersonville Formation interfingers with dolomitic peritidal facies (Geneva Dolostone; Droste and Shaver, 1986c; Hendricks et al., 1994). In the western to southern Cincinnati Arch in Kentucky the Givetian Beechwood or Boyle Formation and locally the overlying Portwood Formation carbonates rest unconformably on various Silurian units. The complex, locally karstic, unconformities in the vicinity of Waco and Irvine, Kentucky were discussed in detail by Brett et al., (2004). On the eastern flank of the Cincinnati Arch, the Middle Devonian unconformities are overstepped by higher erosion surfaces which have removed all earlier Devonian units such that Upper Devonian (Famennian) Ohio-New Albany Shale rests on Wenlock or Llandovery Bisher-Estill formations with a profound unconformity that in some areas exceeds 65 million years in duration. BROAD ISSUES IN SEQUENCE AND EVENT STRATIGRAPHY IN MID-CONTINENT SUCCESSIONS Problems of correlation and interpretation of sequences across different regions have obscured very widespread patterns that point to control by large scale allocyclic processes, including regional tectonics and eustasy that produce regional “layer cake” like patterns (Brett et al., 2007). Some problems in correlation are more apparent than real: the result of semantic differences and historical and/or philosophical differences in the subdivision and naming of units by insular geological surveys. Others result from patterns of complex facies change: condensation, and erosional cutout of units. All of these issues are well illustrated in the problem of correlation of units in the Upper Ordovician to Silurian of the Cincinnati Arch region. Resolution of these issues involves detailed sequence and event stratigraphy in outcrop and drill core as well as careful tracing of key surfaces and biostratigraphy.

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Paradox of TST Bias Although highstand deposits should have the widest geographic distribution and in some instances there is evidence that they once did we note that the intervals herein recognized as argillaceous deeper water deposits (e.g. Massie Shale Member) are typically far less extensive than are the shallow water coarse skeletal limestones. Indeed, units such as the Osgood-Laurel Dolostone, long recognized as mappable lithologic units are comprised of stacked TSTs of two or more sequences. In the latter case, the transgressive carbonates demonstrably merge as the argillaceous highstand deposits that separate them in the Appalachian Basin wedge out (Fig. 6). This is clearly seen in the pinchout/cutout of Silurian shales, such as the lower Estill, the upper Osgood (Massie) and the Waldron Shale, westward from Ohio into Indiana. This pinchout can be shown through careful outcrop/core study to be the result of both craton-ward thinning of the shaly HSTs and, more importantly, erosional truncation. This amalgamation results in a composite unit, which superficially appears to be an unbroken succession of thickened carbonate (Fig. 6). One interpretation of this succession might be that the shaly interval merely changes facies in an upramp direction into fossiliferous grainstone. But this is clearly not the case. In some of the westernmost exposures where the shales persist they retain much of their internal stratigraphy and remain a deeper shelf mudrock unit with offshore fossil assemblages adjacent to the region in which it is removed. Thus, although there are subtle facies changes within the highstand and general thinning owing to failure of clastic mud deposition, it is also clear that shaly facies-representing deeper water environments were once much more widespread. The paradox can be stated simply: one would predict that the deepest facies would record times of most extensive seaways and widest deposition. But in fact the pattern appears to be the opposite: shallower water facies are most extensive. It is just these shallower facies that one might expect to pinch out or merge into peritidal facies approaching area of uplift such as the Findlay-Algonquin Arch. But evidently, the shallowing in these areas was not sufficient to completely terminate deposition of such shallow shelf skeletal carbonate facies. Surely then they were also not sufficient to eliminate deposition during highstands either. This paradox also may be explained relatively simply. During falling stage and lowstands of sea level, the first deposits to become exposed to erosion were the immediately older highstands. The only partly consolidated muds and thin silts were readily stripped off during this interval.

A remaining question, however, is why the erosion frequently removed only the highstand muds and generally did not cut into the subjacent skeletal carbonates- thus, producing the stacking of these carbonates that is typical of cratonic successions. Our tentative explanation is as follows. These porous carbonate sediments were subject to early diagenetic cementation. However, they formed an indurated surface below which physical erosion could not penetrate. Of course, prolonged exposure of these carbonates in subaerial environments could, and in some cases did, lead to dissolutional karsting. But either this phenomenon was rare, and much of the erosion actually occurred in shallow, wave-agitated marine settings, or the evidence of karstification was obliterated when the upper surfaces of the corroded carbonates were subjected to transgressive ravinement during the up-ramp migration of the high energy surf zone. In either case, most surfaces were planar and show little relief other than stylolitization, which may have removed evidence of micro-karstic features.

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Biofacies, Tracking, and Bioevents Fossils are not randomly distributed in rocks. Rather, both the processes, which control ecological distribution and those that influence and bias fossil preservation, are linked to aspects of changing environment and sedimentation patterns. Fossil preservational and ecological information have great utility in reconstructing environments; however, this vast data source is often under-utilized by sedimentologists and sequence stratigraphers. Conversely, in many ways, sequence stratigraphy provides a heuristic model that links physical processes with predictable changes in the distribution of not only taxa but also biocontructional features, such as reefs, trace fossils, and shell beds and their modes of preservation (Brett, 1995, 1998; Witzke et al., 1996; Holland and Patzkowsky, 1996, 2007). In terms of taphonomy, there are strongly predictable trends that relate to changes in sedimentation during sedimentary cycles. Thus, for example many transgressive deposits include strongly reworked, variably disarticulated, whole and fragmented skeletal material. More important the fossils are strongly concentrated into thin to thick beds of shell, bryozoan, and pelmatozoan debris. In many cases, shells show evidence of corrosion and diagenetic alteration, including phosphatic impregnation and early cementation of steinkerns (especially seen in cephalopods), and dark staining (Kolbe et al., 2011). Hardground biotas and local biostromes typically signal breaks in sedimentation that permit colonization of the clean, relatively firm seafloors (McLaughlin et al., 2008). Conversely, early highstand deposits commonly feature fine-grained siliciclastics that may show sparse fossil assemblages. However, thicker shell beds (a few centimeters to decimeters in thickness) are widespread and appear to record periods of sediment starvation, perhaps associated with minor base level rise in small-scale cycles. Some mudstones may show spectacular obrution deposits such as the famed trilobite beds of the Corryville and Waynesville “butter shales” (Brett et al., 2012) and “log jams” of articulated crinoids and other multi-element echinoderms. These deposits indicate mud sedimentation was episodic and occurred in sometimes widespread. Falling stage deposits are typified by thicker, commonly silty to sandy deposits that are sparsely fossiliferous and have fewer and more widely-spaced shell beds. They may feature well-preserved fossils, typically as thin storm lags on the bases of event deposits, such as hummocky crosslaminated siltstones and sandstones. Hence, taphofacies are predictable within sequence stratigraphic frameworks and taphonomy may, in turn, inform sequence interpretations. The strata of the Cincinnati Arch also show numerous patterns of faunal change, some of which are correlated with facies changes and biases related to sequence stratigraphy (Holland, 2000) and others that appear to record extrinsic effects. In the Cincinnatian, a substantial amount of facies control on fossil distributions is apparent. Thus, fossil assemblages show well-documented gradients that have been quantified using gradient analysis techniques such as de-trended correspondence analysis (DCA) (Holland et al., 2001, Miller et al., 2001; Webber, 2002). One of the strongest gradients appears to be related to depth. Such studies provide quantitative support to earlier ideas of bathymetrically zoned, onshore-offshore faunal Benthic Assemblages, such as the Lingula, Pentamerus and Stricklandiid “communities”, which are recognizable in the Silurian of the Cincinnati Arch region. The correlatability of curves of DCA scores based on analysis of assemblages through vertical successions is suggestive of tracking of species and biofacies in response to shifting environments. Moreover, a degree of ecological stability has recently been documented by Holland and Patzkowsky (2004), Malizia and Stigall (2011), and Holland and Zaffos (2011). A majority of

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genera appear to maintain similar positions along quantified gradients (e.g., similar ranges of DC axis 1 scores). At broader time scales, Ordovician and Silurian faunas of the Cincinnati Arch appear to show blocks of relative stability, somewhat similar to the EE subunits documented by Brett and Baird (1995) for the Appalachian basin. For example, Holland and Patzkowsky (1997) documented patterns of abrupt change in brachiopod assemblages within the Upper Ordovician of the Cincinnati Arch, that appear to bracket blocks of related faunas comparable to EE sub-units. However, they did not find as much persistence within these EE subunits nor as high a proportion of change at boundaries as those documented in the pattern of “coordinated stasis” by Brett and Baird (1995) for the Silurian and Devonian of the Appalachian Basin. To some degree, these changes coincide with boundaries of 3rd order sequences and therefore may, in part, be artifacts of gaps in the record (see Holland, 2000). However, they are also in part a reflection of biological changes related to environmental/climatic changes. The change of fossil assemblages at the M4-M5 3rd order sequence boundary (e.g., at the Highbridge Group and Lexington Limestone boundary, approximately the Sandbian-Katian Stage boundary) is correlated with sedimentological changes such as a change from carbonates dominated by micrite to muddy phosphatic and shelly carbonates. Patzkowsky and Holland (1993) interpret this change as indicating a climatic shift from warm somewhat arid climates and mesotrophic conditions to cooler, perhaps wetter and more nutrient rich environments associated with the onset of the Taconic Orogeny, development of a foreland basin and possible upwelling. Certain major bioevents documented in the Ordovician-Silurian strata of the Cincinnati Arch region indicate extinction and/or incursion of faunas from other environments and provinces. For example, the Richmondian invasion, discussed by Holland (1997), Patzkowski and Holland (1996), Stigall (2010), and Dudei and Stigall (2010), reflects immigration of a suite of warmer water taxa including corals and stromatoporoids, derived from lower latitude settings to the northwest. Remarkably these taxa seem to have largely joined endemic taxa without major loss of endemic taxa. This incursion was probably facilitated by an episode of climatic warming in the early Ashgilll the so-called Boda Event. The global Hirnantian extinction was also probably related to rapid climatic cooling and sea level drop. The patterns of this extinction cannot be documented in detail in the Cincinnati Arch region because the Hirnantian record has been deleted by erosion at the Cherokee Unconformity at the Ordovician-Silurian systemic boundary. Although certain major common taxa were exterminated at this time (e.g., the brachiopod Rafinesquina and the trilobite Isotelus) recent studies suggest that the impact of this bioevent was not as severe in the Laurentian mid-continent as many other areas and, indeed, the early Silurian biotas are more diverse than those of the subjacent Richmondian (Zaffos and Holland, 2011). In similar manner recent studies suggest a strong incursion of taxa including certain brachiopods and a suite archaic blastozoan echinoderms (e.g., diploporan cystoids and coronoids) into the Laurentian midcontinent during the late Telychian (Frest et al., 1999, 2011; J. Thomka, unpublished data). This incursion may be related to a brief interval of climatic cooling which culminated in a short-lived glaciation episode in Gondwanaland in the early Wenlock (Caputo, 1998). This latter faunal shift is associated in time with the major global Ireviken bioevent (Jeppsson, 1997; Jeppsson and Calner, 2007) and a strong early Sheinwoodian positive carbon isotopic excursion, which indicates a disturbance of the global carbon cycle.

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The Non-Random Positioning of Bioherms and Biostromes Bioherms and biostromes in the local Paleozoic succession do not occur randomly in the section. Rather they form extensive tracts over vast areas, seemingly at approximately the same time. For example, in the Ordovician of the study area biostromes and small mounds (incorrectly termed “reefs” in some literature) occur at particular laterally extensive horizons. In the region around Louisville horizons rich in colonial rugose corals, tetradiids and stromatoporoids occur at distinct levels at the bases of sequences and apparently associated with transgressive systems tracts. These occur at the base of the Waynesville Formation (sequence C-5 of Holland, 1993), the Bardstown “reefs” at the base of the Liberty Formation (C-6), and the Madison “reef” in the transgressive base of the Whitewater Formation (C-7). The Hitz Member of the Whitewater Formation does not show major coral beds but does show small thrombolitic buildups. In the Silurian, small mounds or bioherms composed of dolomitized micrite with some relict fistuliporoid bryozoans and crinoid holdfasts occur at three specific widespread levels, one at the top of the red Brassfield. A second horizon of bioherms occurs at the upper contact of the widespread echinoderm packstone of the Lewisburg Formation and overlying Massie Shale. Likewise, a third level of very similar mounds occurs at the contact of the Laurel Dolostone and the Waldron Shale at a majority of outcrops in the Tristate area. What processes underlie these widespread “reef” and “thicketing” events”? One indication that these “reefs” are coeval over regions is that they may show lateral facies change within the context of mounded biogenic buildups. Clearly the buildup of organismal mounds must be the response to a widespread allogenic trigger. While some models may predict that reefal buildups would occur in shallow water during falling stages or lowstands, we find little evidence of such a positioning anywhere in the Paleozoic of the Appalachian basin of North American mid-continent. Rather, the mounds are initiated at sharply defined surfaces that show strong evidence of deepening: such as the contact between Osgood and Laurel grainstones and overlying Massie and Waldron mudstones, respectively. These clearly appear to record deepening episodes in which there is also a strong degree of sediment starvation. In shallower water facies, thrombolitic to stromatolitic buildups appear to be initiated in many places on hardgrounds. We would infer that these record periods of stabilization and cementation to form hard surfaces that afforded substrates for the buildups. Again, evidence strongly suggests that the mounds are associated with incipient sea level rise. Moreover, the exact positioning of the mound, starting surface may vary slightly depending upon the paleogeography of the basin. For instance, in the Irondequoit Formation coeval with the Lewisburg Formation, bioherms were initiated on lower carbonate unit near to the basin center, but in shallower areas a second episode of reefing occurs at the next higher and more major flooding surface. This implies that up-ramp locations were too shallow during the earlier phase of the transgression to permit mound formation, but that the latter areas only came into appropriate depths-or sufficient accommodation- to initiate the process of biohermal buildup later during the transgression. The synchronicity of biohermal development and its trigger is considered to reflect sea level rise at a sufficient rate, neither too rapid nor too slow, to permit buildup by carbonate forming organisms –mainly microbial or algal dominated communities, supplemented by skeletonized clonal animals, such as bryozoans, stromatoporoids and tabulates. We argue that this occurs for at least two reasons: First and foremost, the sequestration of terrigenous sediments during this time and perhaps the reduction in suspended fine carbonate sediments resulted in water of high clarity, favoring photosynthesizing organisms-algae and bacteria and perhaps photosymbiotic clonal animals. Second, the rise of base level at a rather rapid rate: centimeters per century may have elicited a response in photosensitive organisms to occupy elevated positions leading to a tendency toward upward mounding.

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The size of bioherms may relate to the rate of sea level rise. More rapid rates and/or influx of more turbid water may result in rapid drowning of incipient bioherms. Conversely, a more steady, gradual rate of rise, and/or cleaner water of carbonate banks may facilitate larger reefal development as is the case of the Gasport reefs that may extend upward for several meters and interfinger with surrounding sediments. In our model the bioherms are a signal of maximum starvation associated with episodes of most rapid rates of sea level rise. In this sense, some bioherms may be equivalent to thin phosphatic-glauconitic crusts and hardground surfaces at the tops of limestones. Indeed, in some cases, the discontinuity surface of the limestone top may become coincident with corrosion surfaces on the external surfaces of bioherms that were killed and draped with later deposited muds, rather than interfingering with them. A further implication of this interpretation is that biohermal buildups may represent relatively little of the total time interval of the full succession. In this sense they might be said to be a rare reflection of the “sediment starved systems tract”. Time-Specific Facies One of the remarkable findings of regional study of Paleozoic facies is the extent to which peculiar or unique features of the sedimentary record may occur at particular, relatively narrow time intervals. Many of these remain very incompletely understood but we note them here as a potentially fruitful indicator of environmental and perhaps climatic-oceanographic conditions that transcend local facies. A) Widespread glauconite beds: the late Llandovery condensed carbonates: e.g., Dayton show a preponderance of glauconitic, pyritic, heavily burrowed carbonates. Possible causes may include mildly reduced iron species present throughout the region associated with low organic input, low sedimentation rates, and pelletized sediments, suggesting a relationship to ironstones in the proximal Appalachian Basin. Likewise, there are very widespread intervals of reddish marine shales that suggest regional or even global times of oxidized conditions. B) Widespread intervals of rhythmically alternating carbonate and shale e.g. in the lower to mid Lexington Limestone and in the mid Silurian Osgood interval. The carbonates are not sharply set off from intervening shales but have fuzzy boundaries and clearly appear to be diagenetic. Fossils within the carbonate bands are typically less compressed than those in intervening shales implying early cementation of muddy sediments. These rhythmites locally seem to grade vertically or laterally into other types of rhythmic patterns such as dark gray and green shale and maroon-green shale rhythms. These appear all to be reflections of some type of primary oscillation perhaps in sediment supply or the relative concentration of allogenic muds to in situ production of carbonate sediments coupled with diagenetic redistribution of carbonate and enhancement of a subtle primary signature. We suspect that it reflects a regular oscillation possibly triggered by Milankovitch-driven climatic cycles. Still to be resolved is why at certain times (e.g., early Katian and latest Llandovery to early Wenlock) these effects are so well manifested in sediments. C) Banded chert-rich facies occur in the Silurian Brassfield, Laurel and Wabash Formations. These banded cream-colored cherts are highly distinctive and may reflect widespread input of silica and/or growth of siliceous organisms, mainly sponges. The formation of siliceous layers seems to record episodes of slow down in sedimentation in which dissolved silica became re-precipitated in the porous sediment filling of burrows in firmgrounds. These siliceous fillings show a gradation into chalky to buff weathering altered (early dolomitized) burrow fills. These burrowed horizons impart a distinct rhythmicity to these quiet water carbonates, which we would relate to the rhythmic nodular carbonates and marly shale noted above. The appearance of chalky alteration rinds may provide a subtle clue to a biogenic source of silica as opposed to input of siliceous ash. Opaline silica, the primary constituent of organism skeletal silica, is a scavenger of magnesium

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ions; the latter are released during recrystallization of the silica to cryptocrystalline quartz producing local dolomitization of surrounding carbonate sediment. Hence, this type of alternation may point to an opaline silica source. ACKNOWLEDGEMENTS We deeply appreciate the help from Tammie L. Gerke and Betty Lou Brett in finalizing this guidebook. The research for this report has been supported by NSF Grant EAR0819715 and a grant from the Donors to the Petroleum Research Fund, American Chemical Society.

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REFERENCES Anderson, R.L., 1980, Reef Structures in the Louisville Limestone (Silurian) in Bullitt County, Kentucky: Unpublished MS Thesis, University of Kentucky, Lexington, Kentucky, 48 p. Bassler, R.S., 1906, The bryozoan fauna of the Rochester Shale: United States Geological Survey Bulletin, v. 292, 137 p. Bergström, S.M., Schmitz, B., Saltzman, M.R., and Huff, W.D., 2010, The Upper Ordovician Guttenberg δ13C excursion (GICE) in North America and Baltoscandia: Occurrence, chronostratigraphic significance, and paleoenvironmental relationships, in Finney, S.C., and Berry, W.B.N., eds., The Ordovician Earth System: Geological Society of America Special Paper, v. 466, p. 37-68. Berry, W.B.N., and Boucot, A.J., 1970, Correlation of the North American Silurian Rocks: Geological Society of America Special Papers, v. 102, 298 p. Black, D.F.B., and Haney, D.C., 1975, Selected structural features and associated dolostone occurrences in the vicinity of the Kentucky River Fault System: Geological Society of Kentucky Annual Field Conference, 27 p. Bradley, D.C., and Kidd, W.S.F., 1991, Flexural extension of the upper continental crust in collisional foredeeps: Geological Society of America Bulletin, v. 103, p. 1416-1438. Brett, C.E., 1995, Sequence stratigraphy, biostratigraphy, and taphonomy in shallow marine environments: Palaios, v. 10, p. 597-616. Brett, C.E., 1998, Sequence stratigraphy, paleoecology, and evolution: Biotic clues and responses to sea-level fluctuations: Palaios, v. 13, p. 241-262. Brett, C.E., and Algeo, T.J., 2001, Sequence stratigraphy of Upper Ordovician and Lower Silurian strata of the Cincinnati Arch region, in Brett, C.E., and Algeo, T.J., eds., Field Trip Guidebook for 1999 Field Conference of the Society of Economic Paleontologists and Mineralogists, Great Lakes Section and Kentucky Society of Professional Geologists, p. 34-46. Brett, C.E., and Baird, G.C., 1995, Coordinated stasis and evolutionary ecology of SilurianDevonian faunas in the Appalachian Basin, in Erwin, D.H., and Anstey, R.L., eds., New Approaches to Speciation in the Fossil Record: Columbia University Press, New York, p. 285315. Brett, C.E., and Ray, D.C., 2005, Sequence and event stratigraphy of Silurian strata of the Cincinnati Arch region: Correlation with New York-Ontario successions: Proceedings of the Royal Society of Victoria, v. 117, p. 175-198. Brett, C.E., Algeo, T.J., and McLaughlin, P.I., 2003, Use of event beds and sedimentary cycles in high-resolution stratigraphic correlation of lithologically repetitive successions: The Upper Ordovician Kope Formation of northern Kentucky and southwestern Ohio, in Harries, P., and Geary, D., eds., High-Resolution Stratigraphic Approaches to Paleobiology: Kluwer Academic Press/Plenum Press, p. 315-350. Brett, C.E., Baarli, B.G., Chowns, T., Cotter, E., Driese, S., Goodman, W., and Johnson, M.E., 1998, Early Silurian condensed intervals, ironstones, and sequence stratigraphy in the Appalachian foreland basin, in Landing, E., and Johnson, M.E., eds., Silurian Cycles: Linking Dynamic Stratigraphy with Atmospheric, Oceanic, and Tectonic Changes: New York State Museum Bulletin, v. 491, p. 89-143. Brett, C.E., Cramer, B.D., McLaughlin, P.I., Kleffner, M.A., Showers, W.J., and Thomka, J.R., 2012, Revised Telychian-Sheinwoodian stratigraphy of the Laurentian mid-continent: Building uniform nomenclature along the Cincinnati Arch: Bulletin of Geosciences, v. 87. Brett, C.E., Goodman, W.M., and LoDuca, S.T., 1990, Sequences, cycles, and basin dynamics in the Silurian of the Appalachian foreland basin: Sedimentary Geology, v. 69, p. 191-244. Brett, C.E., McLaughlin, P.I., and Bazeley, J., 2008, Correlation and faunal analysis of the upper Clays Ferry and Garrard formations (Upper Ordovician: Edenian) in central Kentucky: Implications for sequence stratigraphy, in McLaughlin, P.I., Brett, C.E., Holland, S.M., and Storrs, G., eds., Stratigraphic Renaissance on the Cincinnati Arch: Implications for Upper

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Ordovician Paleontology and Paleoecology: Cincinnati Museum Center Scientific Contributions, v. 2, p. 112-136. Brett, C.E., McLaughlin, P.I., Cornell, S.R., and Baird, G.C., 2004, Comparative sequence stratigraphy of two classic Upper Ordovician successions, Trenton Shelf (New York-Ontario) and Lexington Platform (Kentucky-Ohio): Implications for eustasy and local tectonism in eastern Laurentia: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 210, p. 295-329. Brett, C.E., Zambito, J.J., IV, Hunda, B.R., and Schindler, E., 2012, Mid-Paleozoic trilobite Lagerstätten: Models of diagenetically enhanced obrution deposits: Palaios, v. 27, p. 326-345. Butts, C., 1915, Geology and mineral resources of Jefferson County, Kentucky: Kentucky Geological Survey Report, Series 4, v. 3, 270 p. Caputo, M. V. 1998. Ordovician-Silurian glaciations and global sea-level changes. In Landing, E. and Johnson, M.E., eds., Silurian Cycles, Linkages of Dynamic Stratigraphy with Atmospheric, Oceanic, and Tectonic Changes, New York State Museum Bulletin491:15-25. Catuneanu, O., 2006, Principles of Sequence Stratigraphy: Elsevier, Amersterdam, 375 p. Coe, A.L., ed., 2005, The Sedimentary Record of Sea-Level Change: Cambridge University Press, Cambridge, 287 p. Cocks, L.R.M. and Torsvik, T.H., 2002. Earth geography from 500 to 400 million years ago: A faunal and paleomagnetic review. Journal of the Geological Society, London, 159: 631-644. Conkin, J.E., 2002, Quarry Studies No. 1: Liters of Indiana Inc., Atkins Quarry, Jeffersonville, Indiana: University of Louisville Studies in Paleontology and Stratigraphy, 30 p. Conkin, J.E., and Conkin, B.M., 1972, Guide to the Rocks and Fossils of Jefferson County, Kentucky, Southern Indiana and Adjacent Areas: University of Louisville Reproduction Services, Louisville, 331 p. Conkin, J.E., and Conkin, B.M., 1976, Guide to the rocks and fossils of Jefferson County, Kentucky, southern Indiana and adjacent areas: University of Louisville Studies in Paleontology and Stratigraphy, 238 p. Conkin, J.E., and Conkin, B.M., 1980, Handbook to the strata and fossils of the Falls of the Ohio: University of Louisville Studies in Paleontology and Stratigraphy, 27 p. Conkin, J.E., and Conkin, B.M., 1983, Paleozoic metabentonites of North America, Part 2: Metabentonites in the Middle Ordovician Tyrone Formation at Boonesborough, Clark County, Kentucky: University of Louisville Studies in Paleontology and Stratigraphy, 47 p. Conkin, J.E., and Dasari, M.R., 1986, Capitol Metabentonite in the Trenton Curdsville Limestone of Central Kentucky: University of Louisville Studies in Paleontology and Mineralogy, 14 p. Conkin, J.E., Conkin, B.M., and Lipchinsky, Z.L., 1973, Middle Devonian (Hamiltonian) stratigraphy and bone beds on the east side of the Cincinnati Arch in Kentucky, Part 1: Clark, Madison, and Casey Counties: University of Louisville Studies in Paleontology and Stratigraphy, 45 p. Conkin, J.E., Conkin, B.M., and Lipchinsky, Z.L., 1976, Middle Devonian (Hamiltonian) stratigraphy and bone beds on the east side of the Cincinnati Arch in Kentucky, Part 2: The Kidds Store section, Casey County: University of Louisville Studies in Paleontology and Stratigraphy, 34 p. Cramer, B.D., Brett, C.E., Melchin, M.A., Männik, P., Kleffner, M.A., McLaughlin, P.I., Loydell, D.K., Munnecke, A., Jeppsson, L., Corradini, C., Brunton, F.R., and Saltzman, M.R., 2011, Revised chronostratigraphic correlation of the Silurian System of North America with global and regional chronostratigraphic units and δ13Ccarb chemostratigraphy: Lethaia, v. 44, p. 185202. Cramer, B.D., Kleffner, M.A., and Saltzman, M.R., 2006a, The Late Wenlock Mulde positive carbon isotope (δ13Ccarb) excursion in North America: GFF, v. 128, p. 85-90. Cramer, B.D., Saltzman, M.R., and Kleffner, M.A., 2006b, Spatial and temporal variability in organic carbon burial during global positive carbon isotope excursions: New insight from high

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resolution δ13Ccarb stratigraphy from the type area of the Niagaran (Silurian) Provincial Series: Stratigraphy, v. 2, p. 327-340. Cressman, E.R., 1973, Lithostratigraphy and depositional environments of the Lexington Limestone (Ordovician) of central Kentucky: United States Geological Survey Professional Paper 768, 61 p. Cressman, E.R., and Noger, M.C., 1976, Tidal-flat carbonate environments in the High Bridge Group (Middle Ordovician) of central Kentucky: Kentucky Geological Survey Report of Investigations 18, 15 p. Dattilo, B.F., Brett, C.E., Kirchner, B., and Tsujita, C., 2008, Sediment supply vs. storm winnowing in the development of muddy and shelly interbeds from the Upper Ordovician of the Cincinnati region: Candadian Journal of Earth Sciences, v. 45, p. 245-263. Droste, J.B., and Shaver, R.H., 1986a, Beechwood Member, in Shaver, R.H., Ault, C.H., Burger, A.M., Carr, D.D., Droste, J.B., Eggert, D.L., Gray, H.H., Hassenmueller, N.R., Hassenmueller, W.A., Horowitz, A.S. Hutchison, H.C., Keith, B.D., Keller, S.J., Patton, J.B., Rexroad, C.B., and Wier, C.E., eds., Compendium of Paleozoic rock-unit stratigraphy in Indiana—A revision: Indiana Geological Survey Bulletin, v. 59, p. 11-12. Droste, J.B., and Shaver, R.H., 1986b, Geneva Dolomite Member, in Shaver, R.H., Ault, C.H., Burger, A.M., Carr, D.D., Droste, J.B., Eggert, D.L., Gray, H.H., Hassenmueller, N.R., Hassenmueller, W.A., Horowitz, A.S. Hutchison, H.C., Keith, B.D., Keller, S.J., Patton, J.B., Rexroad, C.B., and Wier, C.E., eds., Compendium of Paleozoic rock-unit stratigraphy in Indiana—A revision: Indiana Geological Survey Bulletin, v. 59, p. 50-52. Droste, J.B., and Shaver, R.H., 1986c, Jeffersonville Limestone, in Shaver, R.H., Ault, C.H., Burger, A.M., Carr, D.D., Droste, J.B., Eggert, D.L., Gray, H.H., Hassenmueller, N.R., Hassenmueller, W.A., Horowitz, A.S. Hutchison, H.C., Keith, B.D., Keller, S.J., Patton, J.B., Rexroad, C.B., and Wier, C.E., eds., Compendium of Paleozoic rock-unit stratigraphy in Indiana—A revision: Indiana Geological Survey Bulletin, v. 59, p. 64-66. Droste, J.B., and Shaver, R.H., 1986d, North Vernon Limestone, in Shaver, R.H., Ault, C.H., Burger, A.M., Carr, D.D., Droste, J.B., Eggert, D.L., Gray, H.H., Hassenmueller, N.R., Hassenmueller, W.A., Horowitz, A.S. Hutchison, H.C., Keith, B.D., Keller, S.J., Patton, J.B., Rexroad, C.B., and Wier, C.E., eds., Compendium of Paleozoic rock-unit stratigraphy in Indiana—A revision: Indiana Geological Survey Bulletin, v. 59, p. 67-68. Droste, J.B., and Shaver, R.H., 1986e, Silver Creek Member, in Shaver, R.H., Ault, C.H., Burger, A.M., Carr, D.D., Droste, J.B., Eggert, D.L., Gray, H.H., Hassenmueller, N.R., Hassenmueller, W.A., Horowitz, A.S. Hutchison, H.C., Keith, B.D., Keller, S.J., Patton, J.B., Rexroad, C.B., and Wier, C.E., eds., Compendium of Paleozoic rock-unit stratigraphy in Indiana—A revision: Indiana Geological Survey Bulletin, v. 59, p. 144-145. Droste, J.B., and Shaver, R.H., 1986f, Speed Member, in Shaver, R.H., Ault, C.H., Burger, A.M., Carr, D.D., Droste, J.B., Eggert, D.L., Gray, H.H., Hassenmueller, N.R., Hassenmueller, W.A., Horowitz, A.S. Hutchison, H.C., Keith, B.D., Keller, S.J., Patton, J.B., Rexroad, C.B., and Wier, C.E., eds., Compendium of Paleozoic rock-unit stratigraphy in Indiana—A revision: Indiana Geological Survey Bulletin, v. 59, p. 147-148. Dudei, N.L., and Stigall, A.L., 2010, Using ecological niche modeling to assess biogeographic and niche response of brachiopod species to the Richmondian Invasion (Late Ordovician) in the Cincinnati Arch: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 296, p. 28-47. Ettensohn, F.R., 1987, Rates of relative plate motion during the Acadian Orogeny based on the spatial distribution of black shales: Journal of Geology, v. 95, p. 572-582. Ettensohn, F.R., ed., 1992a, Changing Interpretations of Kentucky Geology: Layer Cake, Facies, Flexure, and Eustacy: Ohio Division of Geologic Survey Miscellaneous Report 5, 184 p. Ettensohn, F.R., 1992b, Basin flexural models, in Ettensohn, F.R., ed., Changing Interpretations of Kentucky Geology: Layer Cake, Facies, Flexure, and Eustacy: Ohio Division of Geologic Survey Miscellaneous Report 5, p. 9-12.

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Ettensohn, F.R., 2004, Modeling the nature and development of major Paleozoic clastic wedges in the Appalachian Basin, USA: Journal of Geodynamics, v. 37, p. 657-681. Ettensohn, F.R., 2008, The Appalachian foreland basin in the eastern United States, in Miall, A., ed., The Sedimentary Basin of the United States and Canada: Elsevier, Amsterdam, p. 105-179. Ettensohn, F.R., and Brett, C.E., 1998, Tectonic components in third-order Silurian cycles: Examples from the Appalachian Basin and global implications, in Landing, E., and Johnson, M., eds., Silurian Cycles: Linkages of Dynamic Stratigraphy with Atmospheric, Oceanic, and Tectonic Changes: New York State Museum Bulletin, v. 491, p. 145-162. Ettensohn, F.R., and Brett, C.E., 2002, Stratigraphic evidence from the Appalachian Basin for continuation of the Taconian Orogeny into Early Silurian time: Physics and Chemistry of the Earth, v. 27, p. 279-288. Ettensohn, F.R., Hohman, J.C., Kulp, M.A., and Rast, N., 2002, Evidence and implications of possible far-field responses to the Taconian Orogeny: Middle-Late Ordovician Lexington Platform and Sebree Trough, east-central United States: Southeastern Geology, v. 41, p. 1-36. Feldmann, H.R., 1989, Taphonomic processes in the Waldron Shale, Silurian, southern Indiana: Palaios, v. 4, p. 144-156. Foerste, A.F., 1896, An account of Middle Silurian cores of Ohio and Indiana: Cincinnati Society of Natural History Journal, v. 18, p. 161-200. Foerste, A.F., 1897, A report on the geology of the Middle and Upper Silurian rocks of Clark, Jefferson, Ripley, Jennings, and southern Decatur Counties, Indiana: Indiana Department of Geology and Natural Resources Annual Report, v. 21, p. 213-288. Foerste, A.F., 1905, The classification of the Ordovician rocks of Ohio and Indiana: Science, new ser. 22, p. 149-152. Foerste, A.F., 1906, The Silurian-Devonian and Irvine formations of east-central Kentucky: Kentucky Geological Survey Bulletin, v. 7, 127 p. Foerste, A.F., 1917, Notes on Silurian fossils from Ohio and other central states: Ohio Journal of Science, v. 17, p. 187-204. Foerste, A.F., 1929, The correlation of the Silurian section of Adams and Highland Counties with that of the Springfield area: Ohio Journal of Science, v. 29, p. 168-169. Foerste, A.F., 1931a, The paleontology of Kentucky: II, the Silurian faunas of Kentucky: Kentucky Geological Survey Bulletin, v. 36, p. 169-212. Foerste, A.F., 1931b, The paleontology of Kentucky: III, the Silurian faunas of Kentucky: Kentucky Geological Survey Bulletin, v. 36, p. 236-320. Foerste, A.F., 1935, Correlation of the Silurian formations in southwestern Ohio, southeastern Indiana, Kentucky, and western Tennessee: Denison University Science Laboratory Bulletin, v. 35, p. 119-205. Frest, T.J., Brett, C.E., and Witzke, B.J., 1999, Caradocian-Gedinnian echinoderm associations of central and eastern North America, in Boucot, A.J., and Lawson, J.D., eds., Paleocommunities: A Case Study from the Silurian and Lower Devonian: Cambridge Press, New York, p. 638783. Frest, T.J., Strimple, H.L., and Paul, C.R.C., 2011, The North American Holocystites fauna (Echinodermata, Blastzozoa: Diploporita): Paleobiology and systematics: Bulletins of American Paleontology, v. 380, 141 p. Frey, R.C., 1987, The paleoecology of a Late Ordovician shale unit from southwest Ohio and southeastern Indiana: Journal of Indiana, v. 61, p. 242-267. Frey, R.C., 1988, The paleoecology of Treptoceras duseri (Michelinoceratida-Proteoceratidae) from the Late Ordovician of southwest Ohio, in Wolberg, D.L., ed., Contributions to the Paleozoic Paleontology and Stratigraphy in Honor of Rousseau H. Flower: New Mexico Bureau of Mines and Mineral Resources Memoir 44, p. 79-101. Girty, G.H., 1898, Description of a Devonian fauna found in east-central Kentucky: American Journal of Science, v. 6, p. 384-394.

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Gordon, L.A., and Ettensohn, F.R., 1984, Stratigraphy, depositional environments, and regional dolomitization of the Brassfield Formation (Llandoverian) in east-central Kentucky: Southeastern Geology, v. 25, p. 101-115. Hall, J., 1879, The fauna of the Niagara Group in central Indiana: 28th Annual Report of the New York State Museum of Natural History (for 1875), Museum Edition, p. 99-203. Hall, J., 1882, Descriptions of the species of fossils found in the Niagara Group at Waldron, Indiana: Indiana Department of Geology and Natural History, 11th Annual Report, p. 217-345. Halleck, M., 1973, Crinoids, hardgrounds, and community succession: The Silurian LaurelWaldron contact in Indiana: Lethaia, v. 6, p. 239-252. Hendricks, R.T., Ettensohn, F.R., Stark, T.J., Greb, S.F., 1994, Geology of the Devonian Strata of the Falls of the Ohio Area, Kentucky-Indiana: Stratigraphy, Sedimentology, Paleontology, Structure, and Diagenesis: Annual Field Conference of the Kentucky Geological Society, Kentucky Geological Survey, Lexington, 65 p. Holland, S.M., 1993, Sequence stratigraphy of a carbonate-clastic ramp: The Cincinnatian Series (Upper Ordovician) in its type area: Geological Society of America Bulletin, v. 105, p. 306322. Holland, S.M., 1997, Using time/environment analysis to recognize faunal events in the Upper Ordovician of the Cincinnati Arch, in Brett, C.E., and Baird, G.C., eds., Palentologic Events: Stratigraphic, Ecological, and Evolutionary Implications: Columbia University Press, New York, p. 309-334. Holland, S.M., 2000, The quality of the fossil record: A sequence stratigraphic perspective, in Erwin, D.H., and Wing, S.L., eds., Deep Time: Paleobiology’s Perspective: Paleobiology, v. 26 Supplement, p. 148-168. Holland, S.M., and Patzkowsky, M.E., 1996, Sequence stratigraphy and long-term lithologic change in the Middle and Upper Ordovician of the eastern United States, in Witzke, B.J., Ludvigsen, G.A., and Day, J., eds., Paleozoic Sequence Stratigraphy: Views from the North American Craton: Geological Society of America Special Paper 306, p. 117-130. Holland, S.M., and Patzkowsky, M.E., 1997, Distal orogenic effects on peripheral bulge sedimentation: Middle and Upper Ordovician of the Nashville Dome: Journal of Sedimentary Research, v. 67, p. 250-263. Holland, S.M., and Patzkowsky, M.E., 2007, Gradient ecology of a biotic invasion: Biofacies of the type Cincinnatian Series (Upper Ordovician), Cincinnati, Ohio region, U.S.A.: Palaios, v. 22, p. 392-407. Holland, S.M., and Zaffos, A., 2011, Niche conservatism along an onshore-offshore gradient: Paleobiology, v. 37, p. 270-286. Holland, S.M., Meyer, D.L., and Miller, A.I., 2000, High-resolution correlation in apparently monotonous rocks: Upper Ordovician Kope Formation, Cincinnati Arch: Palaios, v. 15, p.73-80. Holland, S.M., Miller, A.I., Dattilo, B.F., Meyer, D.L., and Dieckmeyer, S.L., 1997, Cycle anatomy and variability in the storm-dominated type Cincinnatian (Upper Ordovician): Coming to grips with cycle delineation and genesis: Journal of Geology, v. 105, p. 135-152. Holland, S.M., Miller, A.I., Dattilo, B.F., Meyer, D.L., and Dieckmeyer, S.L., 2001, The detection and importance of subtle biofacies within a single lithofacies: The Upper Ordovician Kope Formation of the Cincinnati, Ohio region: Palaios, v. 16, p. 205-217. Huff, W.D., Bergström, S.M., and Kolata, D.R., 1992, Gigantic Ordovician volcanic ash fall in North America and Europe: Biological, tectonomagmatic, and event-stratigraphic significance: Geology, v. 20, p. 875-878. Jeanette, D.C., and Pryor, W.A., 1993, Cyclic alternation of proximal and distal storm facies: Kope and Fairview Formations (Upper Ordovician), Ohio and Kentucky: Journal of Sedimentary Petrology, v. 63, p. 183-203.

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Jeppsson, L., 1997, The anatomy of the Mid-Early Silurian Ireviken Event and a scenario for P-S events". In Brett, C.E., Baird, G.C.. Paleontological Events: Stratigraphic, Ecological, and Evolutionary Implications. New York: Columbia University Press. pp. 451–492. Jeppsson, L. and Calner, M., 2007. The Silurian Mulde Event and a scenario for secundo—secundo events. Earth and Environmental Science Transactions of the Royal Society of Edinburgh 93 (02): 135–154. Kay, G.M., 1937, Summary of Middle Ordovician bordering Allegheny synclinorium: American Association of Petroleum Geologists Bulletin, v. 32, p. 1397-1416. Keith, B.D., 1988, Regional facies of the Upper Ordovician Series of eastern North America, in Keith, B.D., ed., The Trenton Group (Upper Ordovician Series) of Eastern North America: Deposition, Diagenesis, and Petroleum: American Association of Petroleum Geologists Studies in Geology, v. 39, p. 1-16. Kleffner, M.A., 2000, Conodont biostratigraphy, sequence stratigraphy, and oceanic event record of the Noland Formation and Estill Shale (Lower Silurian) of southern Ohio: Geological Society of American Abstracts with Programs, v. 32, p. 21. Kleffner, M.A., Cramer, B.D., Brett, C.E., Mikulic, D.G., Kluessendorf, J., and Johnson, T., 2012, Lower Silurian of western Ohio—The case of the disappearing Dayton, and unique Midwestern co-occurrence of pentamerid brachiopods with the Gravicalymene celebra Trilobite Association in the Springfield Formation, in Sandy, M.R., and Goldman, D., eds., On and Around the Cincinnati Arch and Niagara Escarpment: Geological Field Trips in Ohio and Kentucky for the GSA North-Central Section Meeting, Dayton, Ohio, 2012: Geological Society of America Field Guide 27, p. 1-18 Kolata, D.R., Huff, W.D., and Bergström, S.M., 2001, The Ordovician Sebree Trough: An oceanic passage to the Midcontinent United States: Geological Society of America Bulletin, v. 113, p. 1067-1078. Kolbe, S.E., Zambito, J.J., IV, Brett, C.E., Wise, J.L., and Wilson, R.D., 2011, Brachiopod shell discoloration as an indicator of taphonomic alteration in the deep-time fossil record: Palaios, v. 26, p. 682-692. Kovach, J., 1974, Stratigraphy and Paleontology of the Pentamerinid Brachiopods of the Niagaran Rocks of Western Ohio and Eastern Indiana: Unpublished PhD Dissertation, Ohio State University, Columbus, Ohio, 366 p. Kuhnhenn, G.L., Grabowski, G.J., Jr., and Dever, G.R., Jr., 1981, Paleoenvironmental interpretation of the Middle Ordovician High Bridge Group in central Kentucky, in Roberts, T.G., ed., Stratigraphy, Sedimentology: Geological Society of America Cincinnati Meeting Field Trip Guidebook, p. 1-30. Linney, W., 1882, Report on the geology of Lincoln County, Kentucky: Kentucky Geological Survey Bulletin, 36 p. Lukasik, M., 1988, Lithostratigraphy of Silurian Rocks in Southern Ohio and Adjacent West Virginia: Unpublished PhD Dissertation, University of Cincinnati, Cincinnati, Ohio, 401 p. Malizia, R.W., and Stigall, A.L., 2011, Niche stability in Late Ordovician articulated brachiopod species before, during, and after the Richmondian Invasion: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 311, p. 154-170. McDowell, R.C., 1983, Stratigraphy of the Silurian Outcrop Belt on the East Side of the Cincinnati Arch, with Revisions in the Nomenclature: Kentucky Geological Survey Professional Paper 1151-F, 27 p. McLaughlin, P.I., and Brett, C.E., 2007, Sedimentological, taphonomic, and biotic signatures of sea level rise in mixed carbonate-clastic successions: Case study of a widespread skeletal limestone interval from the Upper Ordovician of Kentucky-Ohio: Palaios, v. 22, p. 245-267. McLaughlin, P.I., Brett, C.E., Taha McLaughlin, S.L., and Cornell, S.R., 2004, High-resolution sequence stratigraphy of a mixed carbonate-siliciclastic, cratonic ramp (Upper Ordovician; Kentucky-Ohio, USA): Insights into the relative influence of eustasy and tectonics through

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analysis of facies gradients: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 210, p. 267-294. McLaughlin, P.I., Cramer, B.D., Brett, C.E., and Kleffner, M.A., 2008, Silurian high-resolution stratigraphy on the Cincinnati Arch: Progress on recalibrating the layer-cake, in Maria, A.H., and Counts, R.C., eds., From the Cincinnati Arch to the Illinois Basin: Geologic Field Excursions along the Ohio River Valley: Geological Society of America Field Guide 12, p. 119-180. Meyer, D.L., and Davis, R.A., 2009, A Sea Without Fish: Indiana University Press, Bloomington, 368 p. Mikulic, D.G., Kluessendorf, J., Thomka, J.R., and Norby, R.D., 2012, Ordovician sea stacks or Silurian caves: Unconformities and the Brassfield Limestone in Indiana: Geological Society of America Abstracts with Programs, North-Central Section, v. 44, p. 16. Miller, A.I., Holland, S.M., Dattilo, B.F., and Meyer, D.L., 1997, Stratigraphic resolution and perceptions of cycle architecture: Variations in meter-scale cyclicity in the type Cincinnatian: Journal of Geology, v. 105, p. 737-743. Miller, A.I., Holland, S.M., Meyer, D.L., and Dattilo, B.F., 2001, The use of faunal gradient analysis for intraregional correlation and assessment of changes in seafloor topography in the type Cincinnatian: Journal of Geology, v. 109, p. 603-613. Nicoll, R.S., and Rexroad, C.B., 1968, Stratigraphy and conodont paleontology of the Salamonie Dolomite and Lee Creek Member of the Brassfield Limestone (Silurian) in southeastern Indiana and adjacent Kentucky: Indiana Geological Survey Bulletin, v. 40, 92 p. Nielsen, A.T., 2004, Ordovician sea level changes: A Baltoscandian perspective, in Webby, B.D., Paris, F., Droser, M.L., and Percival, I.G., eds., The Great Ordovician Biodiversity Event: Columbia University Press, New York, p. 84-96. Patzkowsky, M.E., and Holland, S.M., 1993, Biotic response to a Middle Ordovician paleoceanographic event in eastern North America: Geology, v. 21, p. 619-622. Patzkowsky, M.E., and Holland, S.M., 1996, Extinction, invasion, and sequence stratigraphy: Patterns of faunal change in the Middle and Upper Ordovician of the eastern United States, in Witzke, B.J., Ludvigsen, G.A., and Day, J., eds., Paleozoic Sequence Stratigraphy: Views from the North American Craton: Geological Society of America Special Paper 306, p. 131-142. Peters, S.E., 2007, The problem with the Paleozoic: Paleobiology, v. 33, p. 161-185. Peters, S.E., and Bork, K.B., 1998, Secondary tiering on crinoids from the Waldron Shale (Silurian, Wenlockian) of Indiana: Journal of Paleontology, v. 72, p. 887-892. Peters, S.E., and Bork, K.B., 1999, Species-abundance models: An ecological approach to inferring paleoenvironments and resolving paleoecological change in the Waldron Shale (Silurian): Palaios, v. 14, p. 234-245. Peterson, W.L., 1981, Lithostratigraphy of the Silurian rocks exposed on the west side of the Cincinnati Arch in Kentucky: United States Geological Survey Professional Paper 1151-C, 29 p. Peterson, W.L., Moore, S.I., Palmer, J.E., and Smith, J.H., 1971, Geologic map of the LaGrange Quadrangle, Oldham County, Kentucky: United States Geological Survey Geologic Quadrangle Map GQ-901. Pope, M.C., and Read, J.F., 1997, High-resolution stratigraphy of the Lexington Limestone (late Middle Ordovician), Kentucky, U.S.A.: A cool-water carbonate-clastic ramp in a tectonically active foreland basin, in James, N.P., and Clarke, J.A.D., eds., Cool-water Carbonates: Society of Economic Paleontologists and Mineralogists Special Publication, v. 56, p. 410-429. Pope, M.C., Read, J.F., Bambach, R.K., and Hofmann, H.J., 1997, Late Middle to Late Ordovician seismites of Kentucky, southwest Ohio, and Virginia: Sedimentary recorders of earthquakes in the Appalachian basin: Geological Society of America Bulletin, v. 109, p. 489-503.

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Rast, N., and Goodman, P.T., 1994, Tectonic and sedimentary consequences of Late Proterozoic and Early and Mid-Paleozoic overthrusting in Kentucky and adjacent states: Northeastern Geology and Environmental Sciences, v. 17, p. 2-9. Rexroad, C.B., 1980, Silurian stratigraphy and conodont paleontology, southeastern Indiana: Field Trips from the Indiana University Campus for the 1980 Geological Society of America, NorthCentral Section Meeting, p. 63-83. Rexroad, C.B., and Kleffner, M.A., 1984, Field trip 5; The Silurian stratigraphy of east-central Kentucky and adjacent Ohio, in Rast, N., and Hay, H.B., eds., Field Trip Guides for the NorthCentral and Southeastern Geological Society of America Meeting, p. 44-65. Rexroad, C.B., Branson, E.R., Smith, O.M., Summerson, C., and Boucot, A.J., 1965, The Silurian formations of east-central Kentucky and adjacent Ohio: Kentucky Geological Survey Bulletin, v. 2, 34 p. Rexroad, C.B., Noland, A.V., and Pollock, C.A., 1978, Conodonts from the Louisville Limestone and the Wabash Formation (Silurian) in Clark County, Indiana and Jefferson County, Kentucky: Indiana Geological Survey Bulletin, v. 36, 19 p. Rowley, D.H., and Kidd, W.S.F., 1981, Stratigraphic relationships and detrital composition of the Middle Ordovician flysch of western New England: Implications for the evolution of the Taconic Orogeny: Journal of Geology, v. 89, p. 199-218. Savage, T.E., 1980, Devonian rocks of Kentucky: Kentucky Geological Survey Report, 6th Series, v. 33, 161 p. Schramm, T.J., 2011, Sequence Stratigraphy of the Late Ordovician (Katian), Maysvillian Stage of the Cincinnati Arch, Indiana, Kentucky, and Ohio, U.S.A.: Unpublished MS Thesis, University of Cincinnati, Cincinnati, Ohio, 215 p. Scotese, C.R., 2001, Atlas of Earth History, vol. 1: Paleogeography: PALEOMAP Project, University of Texas, Arlington, 52 p. Scotese, C.R., 2009, Paleogeographic map archive: PALEOMAP Project, University of Texas, Arlington, 52 p. Shaver, R.H., Ault, C.H., Burger, A.M., Carr, D.D., Droste, J.B., Eggert, D.L., Gray, H.H., Hassenmueller, N.R., Hassenmueller, W.A., Horowitz, A.S. Hutchison, H.C., Keith, B.D., Keller, S.J., Patton, J.B., Rexroad, C.B., and Wier, C.E., 1986, Compendium of Paleozoic rockunit stratigraphy in Indiana—A revision: Indiana Geological Survey Bulletin, v. 59, 203 p. Sloss, L.L., 1963, Sequences in the cratonic interior of North America: Geological Society of America Bulletin, v. 74, p. 93-114. Stigall, A.L., 2010, Using GIS to assess the biogeographic impact of species invasions on native brachiopods during the Richmondian Invasion in the Type-Cincinnatian (Late Ordovician, Cincinnati region): Palaeontologia Electronica, v. 13, 19 p. Stanley, R.S., and Ratcliff, N.M., 1985, Tectonic synthesis of the Taconian Orogeny in western New England: Geological Society of America Bulletin, v. 96, p. 1227-1250. Sumrall, C.D., and Deline, B., 2009, A new species of the dual-mouthed paracrinoid Bistomiacystis and a redescription of Edrioaster priscus from the Upper Ordovician Curdsville Member of the Lexington Limestone: Journal of Paleontology, v. 83, p. 135-139. Thomas, W.A. 1991. The Appalachian-Ouachita rifted margin of southeastern North America. Geological Society of America Bulletin 2, 537-553. Thomka, J.R., Brett, C.E., Cramer, B.D., McLaughlin, P.I., and Kleffner, M.A., 2012, Revised nomenclature and sequence stratigraphic interpretation of the middle Silurian (Telychian to Sheinwoodian) Osgood Formation in the Cincinnati Arch region: Geological Society of America Abstracts with Programs, North-Central Section, v. 44, p. 17. Tillman, C.G., 1961, Stratigraphy and Brachiopod Fauna of the Osgood Formation, Laurel Limestone, and Waldron Shale of Southeastern Indiana: Unpublished PhD Dissertation, Harvard University, Cambrigdge, Massachusetts, 233 p.

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Tobin, R.C., 1982, A Model for Cyclic Deposition in the Cincinnatian Series of Southwestern Ohio, Northern Kentucky, and Southeastern Indiana: Unpublished PhD Dissertation, University of Cincinnati, Cincinnati, Ohio, 483 p. Tobin, R.C., and Pryor, W.A., 1981, Sedimentological interpretation of an Upper Ordovician carbonate-shale vertical sequence in northern Kentucky, in Roberts, T.G., ed., Geological Society of America 1981 Annual Meeting Field Trip Guidebook, p. 1-10. Vail, P.R., Mitchum, R.M., and Thompson, S., III, 1977, Seismic stratigraphy and global changes of sea level, in Payton, C.E., ed., Seismic Stratigraphy—Application to Hydrocarbon Exploration: American Association of Petroleum Geologists Memoir, v. 26, p. 63-81. Van Wagoner, J.C., and Bertram, G.T., eds., 1995, Sequence Stratigraphy of Foreland Basin Deposits: American Association of Petroleum Geologists Memoir, v. 64, 487 p. Van Wagoner, J.C., Mitchum, R.M., Campion, K.M., and Rathmanian, V.D., 1991, Siliciclastic Sequence Stratigraphy in Well Logs, Core, and Outcrops: Concepts for High-Resolution Correlations of Time and Facies: American Association of Petroleum Geologists Methods in Exploration, v. 7, 55 p. Watkins, R., and McGee, P.E., 1998, Secondary tiering among Silurian epibionts in the Waldron Shale, Indiana: PaleoBios, v. 18, p. 12-20. Webber, A., 2002, High-resolution faunal gradient analysis and an assessment of the causes of meter-scale cyclicity in the type Cincinnatian Series (Upper Ordovician): Palaios, v. 17, p. 545555. Weir, G.W., Peterson, W.L., and Swadley, W.C., 1984, Lithostratigraphy of Upper Ordovician Strata Exposed in Kentucky: United States Geological Survey Professional Paper 1151-E, 121 p. Witzke, B.J., Ludvigson, G.A., and Day, J., eds., 1996, Paleozoic Sequence Stratigraphy: Views from the North American Craton: Geological Society of America Special Paper 306, 446 p. Young, S.A., Bergström, S.M., Holmden, C., Patterson, W.P., and Saltzman, M.R., 2003, Paleooceanographic aspects of the early Chatfieldian (upper Middle Ordovician) positive δ 13C excursion (GICE): Geological Society of America Abstracts with Programs, v. 35, p. 600. Zaffos, A., and Holland, S.M., 2012, Abundance and extinction in Ordovician-Silurian brachiopods, Cincinnati Arch, Kentucky and Ohio: Paleobiology, v. 38, p. 278-291.

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IGCP 591 PRE-MEETING: FIELD TRIP ROADLOG AND STOP DESCRIPTIONS FOR DAY 1

Figure 28. Route Map for Day 1. Field Trip in Central Kentucky. Stops comence at Lexington, KY and conclude at Morehead, KY (I-64) SW of Emerson. From Google Maps.

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R OA D L OG , DA Y 1 T otal Descr iption of R oute M ileage 0.0 0.1

Leave UC Geology-Physics Bldg; turn right on Clifton Avenue and keep LEFT Junction Martin Luther King Boulevard; TURN LEFT 1.0 Junction Central Parkway; stay in middle lane and continue across bridge over I-75; 1.1 KEEP RIGHT onto entrance ramp to I-75 southbound 3.6 Union Terminal (Cincinnati Museum Center) on left 4.7 Brent Spence Bridge over Ohio River; enter Commonwealth of Kentucky 6.5-6.7 “Cut-in-the-Hill” road cut on right side of I-75; exposes Edenian Kope Formation; note alternating shale/limestone cycles Florence Mall; site of famed edrioasteroid hardground in Coryville Member 20.3 Exit 175 for Big Bone Lick; famed “birthplace of American Vertebrate paleontology; abundant Pleistocene (