Mississippian (Late Oseagean) Ammonoids from the New Providence Shale Member of the Borden Formation, North-Central Kentucky
The Mississippian ammonoids Polaricyclus conkini new species, P. ballardensis (Gordon, 1965), Winchelloceras knappi new species, and Cantabricanites? greenei (S. A. Miller, 1892) occur with Gnathodus texanus Zone conodonts near the base of the New Providence Shale Member of the Borden Formation in north-central Kentucky. Both ammonoids and conodonts indicate an early late Osagean (lower Keokuk equivalent) age corresponding to the middle or, more probably, the late Chadian (latest Tournaisian or early Vise´an) portion of the Fascipericyclus–Ammonellipsites Zone.
Journal of Paleontology, Vol. 78, No.6, 2004, 1128-1137.