Silurian Conodonts from Wills Mountain Anticline, Virginia, West Virginia, and Maryland

Conodont biostratigraphy is established for complete sections of the Mifflintown, Wills Creek, and Tonoloway Formations along the Wills Mountain anticline in the central Appalachian Mountains. The Rochester Member is renamed the Cosner Gap Member of the Mifflintown Formation.

The succession of conodont faunas described for these formations ranges in age from latest Wenlock through Pridoli. The fauna includes 46 forms (species) assignable to the form genera Hindeodella, Ligonodina, Lonchodina, Neoprioniodus Ozarkodina, Panderodus, Plectospathodus, Spathognathodus, and Trichonodella. Sixteen new form species and subspecies are described, and twelve of these are named: Ligonodina brevis, Ozarkodina edithae mariae, O. typica intermedia, O serrata, O. 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 Appalachian Mountains. Eleven multielement conodont species are recognized using open nomenclature.

Spathognathodus primus and S. sagitta bohemicus lineages in the fauna are important in delimiting six local concurrent range zones. Three zones are described for the Mifflintown Formation: the S. sagitta bohemicus, S. bicornutus, and S snajdri Zones. Three zones are described for the Wills Creek and Tonoloway Formations: the Spathognathodus tillmani, S. crispus, and S. steinhornensis eosteinhornensis Zones. The Gedinnian form Icriodus woschmidti does not appear lower than the base of the New Creek Limestone or, possibly, the upper few meters of the Keyser Limestone.

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

Published: January 01, 1975