Conodonts from the Upper Olentangy Shale (Upper Devonian, central Ohio) and stratigraphy across the Frasnian-Famennian boundary

The Upper Olentangy Shale of Ohio, a green pyritic shale interbedded with t hin dark gray shale beds, disconformably overlies the lithologically simila r Middle Devonian Lower Olentangy Shale. The muds were deposited in a quiet offshore environment on the distal margin of the Appalachian Basin during the Late Frasnian through Early Famennian. The Upper Olentangy Shale contai ns abundant and diverse conodonts of MN Zone 13 and the Middle triangularis Zone, The Frasnian-Famennian boundary is 4-8 cm below the base of the Huro n Shale at the Olentangy Shale type section in Delaware, Ohio. The boundary interval is a green shale containing a mixed highest Frasnian (e.g., Palma tolepis bogartensis, P. linguiformis) and lowest Famennian (e.g., P. delica tula, P. subperlobata, P. triangularis) conodont fauna. An ash horizon, pyr itic bed, finely laminated dark shale, and a thin green-blue shale comprise the upper 3 cm of the Olentangy, and contain a conodont fauna indicative o f the Middle triangularis Zone.