CONODNT BIOSTRATIGRAPHY NEAR THE MISSISSIPPIAN/PENNSYLVANIAN SYSTEM BOUNDARY IN WESTERN KENTUCKY
Conodonts are uncommon at the Manhattan Branch site and the Durham Chapel site produced only one indeterminate element. The former, however, included three juvenile Idiognathodus Pa elements indicating a Pennsylvanian age, which is not in agreement with 1960's mapping. Previous work at both sites by the Kentucky Geological Survey, however, has suggested that these rocks are basal Pennsylvanian. On the bases of limited evidence, a Morrowan or Atokan age seems most likely.
The undifferentiated Caseyville/Tradewater section produced 188 identifiable elements dominated by Idiognathodus. Most important stratigraphically are Idiognathoides (Morrowan/Atokan) and morphologies of Neognathodus that suggest a late Atokan age. Hindeodus and Idioprioniodus are rare; Diplognathodus is represented by a single specimen and Ubanites by one questionable element. Conodont biofacies associations of the Caseyville/Tradewater reflect a shallow shelf, marine environment of generally low to moderately elevated energy.