FRASNIAN CONODONTS FROM THE CASHAQUA AND RHINETREET SHALES OF WESTERN NEW YORK, EQUIVALENT STRATA IN THE DOWELLTOWN MEMBER OF THE CHATTANOOGA SHALE IN TENNESSEE, AND BIOSTRATIGRAPHIC CONTROL IN RELATION TO NEW U/PB DATES OF THE BELPRE TEPHRA SUITE, APPALACHIAN BASIN, UPPER DEVONIAN (MIDDLE FRASNIAN), EASTERN NORTH AMERICA

The Belpre Tephra suite from the Chattanooga Shale in eastern Tennessee and the lower Rhinestreet Shale in western New York yielded high-precision CA-TIMS U-Pb zircon dates of 375.40 +/-0.126 Ma from “tephra 06” at Little War Gap, TN and 375.32 +/- 0.14 Ma from “tephra 7.67” at Eighteenmile Creek, NY. While these dates are identical within analytical error, the conodont zonation for the two localities does not correlate. The date yielding ash bed from the Chattanooga Shale at Little War Gap is MN 8 based on the co-occurrence of Ancyrognathus barba and Palmatolepis housei. The date yielding ash from the Rhinestreet Shale in Erie County, NY is older, MN 7, based on the occurrence of Ancyrognathus sp. L of Klapper and the the goniatite Naplesites inyx. A very diverse conodont fauna from the upper Cashaqua Shale supports the older biostratigraphic assessment of the strata in New York, this fauna includes Ancyrognathus ancyrognathoideus, Ancyrodella nodosa, Icriodus symmetricus, Palmatolepis bohemica, P. gatovskyi, P. punctata, P. reimersi, and P. spinata.