Condodont biostratigraphy has been established for complete sections of the Mifflintown, Wills Creek, and Tonoloway formations along the Wills Mountain anticline in the Central Appalachians. Beds in the Central Appalachians formerly called the Rochester Formation have been renamed the Cosner Gap Member of the Mifflintown Formation. The type section of the unit is at Cosner Gap, northwest of Maysville, Granty Count, West Virginia. Use of the name, Rochester Fornation is restricted to the New York section.

The succession of conodont faunas described for these formations range from latest Wenlock through Pridoli in age. The fauna includes 46 form species assignable to the form genera Hindeodella, Ligonodina, Lonchodina, Neoprioniodus, Ozarkodina, Panderodus, Plectospathodus, Spathoenathodus, and Trichonodella. Sixteen new form species are described and twelve of these are named: Ligonodina brevis, Ozarkodina edithae mariae, Q. typica intermedia, O. serrata, Q. sinuosa, O. ziegleri crassatoides, Spathognathodus bicornutus, S. primus highlandensis, S. primus multidentatus, S. tillmani, S. walliseri, and Synprioniodina lowryi. One platform species, possibly representing a new form genus, occurs in the upper Tonoloway Formation. The important European forms Spathognathodus sagitta bohemicus., S. snajdri, S. crispus, and S. steinhornensis eosteinhornensis, are reported for the first time from the Central Appalachians. Eleven multi-element conodont species are recognized using open nomenclature.

The faunas of the S. sagitta bohemicus, S. snajdri, S. crispus, and S. steinhornensis eosteinhornensis zones correlate with the sagitta, snajdri horizon of the siluricus, crispus, and eosteinhornensis zones of Walliser. The S. bicornutus and S. tillmani zones are tentatively correlated with Walliser's crassa and latialatus zones. The ploeckensis Zone of Walliser was not identified, but its stratigraphic position would be similar to that of the unzoned interval of the middle third of the McKenzie Member of the Mifflintown Formation.