AN ABSTRACT OF THE THESIS OF William Frederick Koch IIfor the degree of Doctor of Philosophy in Geology presented on December 8, 1978 Title: BRACHIOPOD PALEOECOLOGY, PALEOBIOGEOGRAPHY, AND BIOSTRATIGRAPHY IN THE UPPER MIDDLE DEVONIAN OF EASTERN NORTH AMERICA: AN ECOFACIES MODEL FOR THE APPALACHIAN, MICHIGAN, AND ILLINOIS BASINS Abstract approved; Signature redacted for privacy. A. J, Boucot Articulate brachiopod communities sensitive to environmental factors, especially depth and distance from shore, are described from the upper Middle Devonian (upper Eifelian and Givetian; Cazenovia, Tioughnioga, and Taghanic stages of eastern North America) of eastern North America. The Subrensselandia, Cupularos- trum, Mediospirifer, Tropidoleptus, Devonochonetes, Mucrospirifer, Atrypid-Strophodontid, Ambocoeliid, Pacificocoelia, Truncalosia, and Camarotoechia Communities are described from the Hamilton Group of the Appalachian and Illinois Basins. The Cupularostrum, Rhipido thyris, Orthospirifer, Tropidoleptus, Mucrospirifer, Elytha, Spinatrypa, Hypothyridina-Ambocoeliid, Rhys s ochonetes, and Leio- rhynchus Communities are described from the Tully Formation of the Appalachian Basin. The Subrensselaxdia, Stringocephalus, Rhipidothyris, Cupularostrum, Atrypid- Gypidulinid, Devonochonetes, Cyrtina-Athyris, Camarotoechia, and Longispina Communities are described from the sub-Taghanic Traverse Group of the Michigan Basin. The Rens selandia, Chonetid, Pentamerella- Orthospirifer- Cranaena, Spiriferid-Atrypid, Mucrospirifer, Emanuella, and Leiorhynchus Communities are described from the Cedar Valley Formation and correlative strata exclusive of the Appalachian Basin. The Subrens s elandia, Tropidoleptus, Mucrospirifer- Pholidostrophia, Atrypid- Gypidulinid, Chonetid- Leptaena, Br evi s pirife r, Emanu ella, and Warrenella Communities are described from the Dundee and Rogers City Formations and correlative strata exclusive of the Appalachian Basin. The evolution of these brachiopod communities is traced from the Emsian through the early Famennian by assigning related commu- nities to Community Groups. The temporal changes in the Community Groups are discussed in terms of the constituent genera and communi- ties,Communities not assigned to Community Groups are also con- sidered. The Leptaena- Schizophori.a As semblage Zone is defined to include strata correlative with the Union Springs and Cherry Valley Formations of New York. The Fjmbrispirifer-PentagoniaAsemblage Zone is defined to include strata correlative with the Centerfield Mem- ber of New York. The Rhyssochonetes-Hypothyridina Assemblage Zone is defined to include strata which correlate with the Tully Forma- tion of New York.These assemblage zones are the basis for detailed correlation of the upper Middle Devonian strata of eastern North America. The late Middle Devonian fauna of eastern North America represents a mixture of older Eastern Americas Realm and Old World Realm faunas; many older Eastern Americas Realm stocks died out during the earlier Eifelian.Other Old World Realm genera migrated into the Eastern Americas Realm during transgressions associated with the Leptaena- Schizophoria and Rhy s sochonetes - Hypothyridina Assemblage Zones; these genera distinguish these zones from older and younger rocks. The Eastern Americas Realm of the late Middle Devonian is divisible into two subprovinces. The Appohimchi Subprovince occu- pies the Appalachian and Illinois Basins and the clastic shelf to the east of the Appalachian Basin.The Michigan Basin-Hudson Bay Low- land Subprovince occupies a broad carbonate platform extending from Michigan west to Iowa and north to Hudson Bay.Provinciality between these subprovinces rose from the base of the Cazenovia to a peak at the time of the deposition of the Skaneateles Formation, fell during the Fimbrispirifer-Pentagonia As semblage Zone, rose during the upper Tioughnioga, and declined sharply during the Taghanic. The Fimbrispirifer-Pentagonia Assemblage Zone is associated with a transgression and change in current patterns which allowed Appohimchi genera to migrate onto the Michigan carbonate platform. Profiles of depositional topography are constructed for several intervals of late Middle Devonian time.Shelf (undathem), slope (clinothem), and basinal (1 ondathem) deposits are distinguished on these profiles.Chains of communities occur along these profiles. Benthic Assemblages 1 and 2 are on the shelf,Benthic Assemblage 3 ranges from shelf through slope,Benthic Assemblage 4 from slope to basin, and Benthic Assemblage 5 is basinal.Migrations of community chains and shelf margins correspond to transgressionsand regres sions.Biostratigraphic and lithostratigraphic data allow tracing of seven transgressive-regressive events overmuch of eastern North America; these cycles can be used to refine correlationsbased on other stratigraphic techniques. Brachiopod Paleoecology, Paleobiogeography, and Biostratigraphy in the upper Middle Devonian of Eastern North America: An Ecofacies Model for the Appalachian, Michigan, and Illinois Basins by William Frederick Koch II A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Completed December 8, 1978 Commencement June 1979 ACKNOWLEDGEMENTS I wish to greatly thank Arthur J. Boucot for his support and assistance in all, aspects of this study.I thank J. Granville Johnson for many discussions of the ideas presented in this study.To Keith F. Oles, Andrew G. Carey, Jr., and Henry A. Froelich go thanks for critically reviewing this manuscript and for helpful com ments on my work. Especially great thanks go to G. Arthur Cooper for his assis tance during the summers I spent examining collections at the United States National Museum. Discussions with Dr. Cooper were of the highest value in understanding the stratigraphy and paleontology of the upper Middle Devonian rocks of eastern North America. Also I thank Frederick J. Collier for his assistance at the United States National Museum and William A. Oliver for the helpful discussions of Devonian paleobiogeography. Thanks are also due to Lawrence V. Rickard for discussions of the Middle Devonian stratigraphy of New York and to John Innes for discussions of Pennsylvania stratigraphy.I thank A. W. Norris for the permission to examine collections from the James Bay region at the Institute of Petroleum and Sedimentary Geology in Calgary. Great thanks go to John M. Dennison for discussions of this study and for information on the Middle Devonian stratigraphy of Maryland, Virginia, and West Virginia.I thank Michael R. House for examining ammonites which I collected. Thanks are due to Donald G. Mikulic for showing me the out- crops of the Milwaukee and Lake Church Formations in Wisconsin. Special thanks go to Jed Day for assisting me in the field during the summer of 1977.Similarly, I thank Thomas L. DeKeyser for many hours of stimulating discussions on all aspects of paleontology and sedimentary geology; especially for his help in the development of many ideas on ecofacies modeling.I also thank Thomas J. De Vries for his assistance, particularly in the paleobiogeographic modeling. This study was partially financed by a Grant-In-Aid of Research from Sigma Xi, the Scientific Research Society of North America. Support also was provided through a graduate scholarship from the Standard Oil Company of California, for which I was nominated bythe Graduate Committee of the Oregon State University Geology Depart- ment. TABLE OF CONTENTS INTRODUCTION 1 Limits of Study 2 Previous Studies 4 METHODS OF STUDY 12 BRACHIOPOD COMMUNITY PALEOECOLOGY 15 Brachiopod Communities of the Hamilton Group in the Appalachian and Illinois Basins 19 Brachiopod Communities of the Tully Limestone and Correlative Strata in the Appalachian Basin 34 Brachiopod Communities of the Sub- Taghanic Traverse Group of the Michigan. Basin 42 Brachiopod Communities of the Cedar Valley Limestone and Correlative Strata Outside of the Appalachian Basin 52 Brachiopod Communities of the Dundee and Rogers City Limestones and Correlative Strata Outside of the Appalachian Basin (Leptaena-Schizophoria Assemblage Zone) 58 COMMUNITY EVOLUTION 66 Rensselandiid Community Group 66 Orthospirifer Community Group 67 Devonochonete s Community Group 74 Elytha Community Group 77 Atrypid- Gypidulinid Community Group 81 Ambocoelild Community Group 82 Evolutionary Relationships of Unassigned Communities 83 BIOSTRATIGRAPHY 89 Leptaena-Schizophoria Assemblage Zone 90 Fimbrispirifer-Pentagonia As semblage Z ohe 94 Rhyssochonetes-Hypothyriina Assemblage Zone 96 PALEOBIOGEOGRAPHY 99 Mixture of Eastern Americas Realm and Old World Realm Faunas in the Upper Middle Devonian of Eastern North America 101 Migrations of Old World Brachiopods intothe Eastern Americas Realm During the Late Middle Devonian 102 Provinciality Within the Eastern AmericasRealm 104 Transition Zone Between the Appohimchi andMichigan Basin-Hudson Bay Lowland Subprovinces 117 Boundary Between the Appohimchi Subprovinceand the Michigan Basin-Hudson Bay Lowland Subprovince 118 Boundary Between the Eastern AmericasRealm and the Old World Realm During the Late MiddleDevonian 125 AN ECOFACIES MODEL 130 Fossils and Rocks: A Shelf to Basin Profile 130 Regional Correlation through Local Changesof Sea Level 147 Summary The Late Middle Devonian of Eastern North America 157 REFERENCES CITED 170 Appendix1Locations of Collections 182 Hamilton Group Atrypid Str ophodontid Community 183 Mucrospirifer Community 196 Ambocoeliid