Most Silurian conodont biostratigraphies of the North American Midcontinent Basins and Arches region (NAMBA) were completed prior to significant revision of taxonomy and/or ranges of several conodonts important for lower Silurian (Llandovery and Wenlock) zonation by Lennart Jeppsson, Richard Aldridge, and Peep Männik during the last ten years.  As a result, correlations of lower Silurian strata in NAMBA, including those of Ohio and western New York, based on conodont biostratigraphies developed prior to 1997 need to be re-examined.  This study presents a revised conodont biostratigraphy and recently published and preliminary d¹³C_carb chemostratigraphy for lower Silurian strata of Ohio and western New York as a means to effect a revised correlation for those strata.

  The Distomodus kentuckyensis Zone, Pterospathodus eopennatus Superzone, Pt. celloni Superzone, Pt. amorphognathoides amorphognathoides Zonal group, Pt. procerus Superzone, Kockelella ranuliformis Superzone, Ozarkodina sagitta rhenana Zone, and K. walliseri Zonal group are developed in the lower Silurian, Brassfield Formation-Lilley Formation sequence, of southern Ohio.  The Peebles Dolomite lacks diagnostic conodonts. The D. kentuckyensis Zone, Pranognathus tenuis Zone, Pt. amorphognathoides amorphognathoides Zonal group, K. ranuliformis Superzone, and K. walliseri Zonal group are developed in the lower Silurian, Brassfield Formation-Laurel (of Ohio) Formation sequence, of west-central Ohio.  The Euphemia, Springfield, Cedarville, Waldron and Louisville formations lack diagnostic conodonts.  The D. kentuckyensis Zone, P. tenuis Zone, Pt. eopennatus Superzone, Pt. celloni Superzone, Pt. amorphognathoides amorphognathoides Zonal group, K. ranuliformis Superzone, Ozarkodina sagitta rhenana Zone, and K. walliseri Zonal group are developed in the lower Silurian, Neagha Shale-Goat Island Dolomite, of western New York.  The Eramosa Dolomite lacks diagnostic conodonts. The Sheinwoodian Ireviken Excursion is recorded in the lower Silurian, Estill-Lilley sequence, in southern Ohio; Osgood-Laurel (of Ohio) sequence, in west-central Ohio; and Irondequoit-Goat Island sequence, in western New York. The Homerian Mulde Excursion is recorded in the lower Silurian, Waldron-Louisville sequence, in west-central Ohio.