The stratigraphical position of the Middle Jurassic (Bathonian) Stonesfield Slate of Stonesfield, Oxfordshire, UK

Abstract

Cored boreholes recently drilled at Stonesfield, and sections in disused shafts, indicate that the Stonesfield Slate was formerly mined from three levels within the Taynton Limestone Formation. The ‘slate’ can no longer be regarded as a member of the Sharp's Hill Formation, as this is separated from the overlying Taynton Limestone Formation by the newly defined Charlbury Formation. The status of the Sharp's Hill Formation is reviewed and a revised definition is presented. A type horizon of the Procerites progracilis ammonite Biozone of the Bathonian Stage cannot be designated, but the Charlbury and Taynton Limestone formations, which yield the diagnostic fauna, are attributed to the zone.