REVISED MIDDLE TO UPPER AERONIAN AND TELYCHIAN (LOWER SILURIAN) CONODONT BIOSTRATIGRAPHY FOR THE EASTERN PORTION OF THE MIDWESTERN BASINS AND ARCHES REGION (NEW YORK, OHIO, KENTUCKY, AND INDIANA)

Middle to upper Aeronian and Telychian strata throughout the eastern portion of the Midwestern Basins and Arches region (MBA) in New York, Ohio, Kentucky, and Indiana are assignable to five conodont zones or superzones. The Neagha Shale and Reynales Limestone of New York, red Brassfield of Ohio, golden Brassfield of Indiana, and possibly Oldham Limestone of Kentucky are within the middle Aeronian Pranognathus tenuis Zone. The Lower Sodus Shale of New York is within the upper Aeronian or possibly lower Telychian Distomodus staurognathoides Zone. The Merritton Limestone, Sauquoit Shale, Wolcott Furnace Hematite, and Wolcott Limestone and possibly the Upper Sodus Shale of New York, the Waco Formation of Ohio, the Lulbegrud Shale and Waco Formation of Kentucky, and the Lee Creek Formation of Indiana are within the Telychian Pterospathodus eopennatus Superzone. The lower part of the Williamson Shale of New York, including the Second Creek Phosphate, is within the Telychian Pterospathodus celloni Superzone. The Westmoreland Hematite, Willowvale Shale, upper part of the Williamson Shale, Rockway Dolostone and possibly Dawes Sandstone of New York, Dayton Formation, lower part of Osgood Formation, and Estill Shale (except for upper part) of Ohio, the Estill Shale (except for upper part) and lower part of Osgood Formation in Kentucky, and lower part of Osgood Formation in Indiana are within the upper Telychian Pterospathodus amorphognathoides amorphognathoides Zonal group. Two significant unconformities are recognized throughout the eastern portion of the MBA, at the base of strata assigned to the Pt. eopennatus Superzone, and at the base of strata assigned to the Pt. a. amorphognathoides Zonal group. Strata assigned to the conodont zones represented by those unconformities, the D. staurognathoides Zone and Pt. celloni Superzone, are currently only recorded from the west-central New York region of the eastern portion of the MBA.