Ordovician System Stratigraphic Study Depositional environments and sequence stratigraphy of upper Ordovician epicontinental deep water deposits, eastern Iowa and southern Minnesota (Abstract) Carbonate component chemostratigraphy and depositional history of the Ordovician Decorah Formation, Upper Mississippi Valley (Abstract) Does the Ordovician "Guttenberg Event" Carbon Isotope Excursion Extend Shoreward into the Detrital Shale Belt of the Decorah Formation? (Abstract) Regional Relations of Galena Group Strata (Ordovician) in the Mississippi Valley Area, Minnesota, Iowa, Illinois, and Missouri (Abstract)