ABSTRACT

Microfossils are recovered and reported for the first time from the 'Silurian subsurface of Ohio (from the Stray "Clinton"-"Packer Shell" stratigraphic interval). A conodont biostratigraphy is developed for the two units. The Stray "Clinton" contains a conodont fauna (ie., Ozarkodina hassi, 0. oldhamensis, Icriodella deflecta) typical of the late middle Llandovery (Silurian, Fronian, C1-C3), and is a nearshore marine deposit. The "Packer Shell" contains a conodont fauna (ie., Pterospathodus celloni, P. amorphognathoides) typical of the late Llandovery (Telychian, C5-C6), and is also a nearshore marine deposit. The Stray "Clinton"-"Packer Shell" contact is an unconformity.

The Stray "Clinton" and "Packer Shell" are correlated with Ohio Valley-Great Lakes Region Silurian strata about which detailed information of the conodont distribution is available. The Stray "Clinton" correlates with the lower Noland Formation of east-central Kentucky and southern Ohio, and with the middle and upper part of the formation designated as the Reynales Formation at the Niagara Gorge. The "Packer Shell" correlates with the uppermost Noland Formation (uppermost Waco or Dayton Limestone Members) of east-central Kentucky and southern Ohio, and with the lower Rockway Dolomite Member of the Irondequoit Formation at the Niagara Gorge.