THE DEVONIAN/CARBONIFEROUS BOUNDARY AND THE HOLOTYPE OF SIPHONODELLA SULCATA (HUDDLE 1934) IN THE UPPER NEW ALBANY SHALE, ILLINOIS BASIN, SOUTHERN INDIANA

The upper New Albany Shale in southern Indiana consists of the Jacobs Chapel, Henryville, Underwood, and Falling Run beds (descending order) within the upper Clegg Creek Member, and the Ellsworth Member. Bispathodus aculeatus aculeatus, Branmehla bohlenana, Br. inornata, Cryptotaxis culminidirecta, Palmatolepis glabra ssp., Pa. gracilis gracilis, and Protognathodus sp. were recovered from the upper Clegg Creek below the Falling Run Bed and indicate the Devonian praesulcata Zone. The holotype of Siphonodella sulcata (Huddle, 1934) is from locality 9 of Huddle (1934), this site along US Alt. 31 is now covered and the holotype has been lost. Indiana Geological Survey Drill Hole (SDH) 324, eight km to the northwest of locality 9 contains diminutive specimens of Bispathodus, Branmehla, Polygnathus communis communis, and Si. sulcata indicative of the lowest Carboniferous sulcata Zone. The sulcata Zone conodonts occur in association with the brachiopods Subglobosochonetes seymorensis, Rhipidomella newalbaniensis, Schuchertella sp., Rhynchopora prisca, and Sphenospira sp. cf. S. alta. A remarkable concentration of conodonts associated with lingulid brachiopods - Langella? sp. - was also reported from the black shale of the Henryville Bed in the SDH 324 core. The Henryville contains numerous conodonts concentrated in laminae within the black shale, including Bispathodus, Po. c. communis, Pseudopolygnathus sp., Si. sulcata, Si. duplicata, Si. cooperi, and Si. sandbergi indicative of the sandbergi Zone. The holotype Siphonodella sulcata likely came from a conodont-rich horizon in the Henryville Bed. The Devonian-Carboniferous Boundary is placed at the base of the Ellsworth Member, and the base of the Falling Run Bed in the Clegg Creek Member; a significant disconformity is present between the greenish-gray shales of the Ellsworth and Henryville Bed, and where the Ellsworth is absent, at the top of the upper Clegg Creek black shales at the base of the Falling Run Bed or base of the Henryville Bed.