Discoscaphites binodosus Subzone
This subzone is only currently used in northern England (Whitham, 1993).
Base: The base of the subzone is the base of the Sewerby Steps Marl (Whitham, 1993).
Top: The subzone equates with the youngest exposed chalk in northern England, and so its top is undefined.
Range of index species: The index ranges from a short distance above the base of the nominate subzone to the top of the exposed subzone (Whitham, 1993).
Faunal abundance & preservation: The subzone is quite fossiliferous, with a diverse fauna.
Bio-markers: Rare Offaster pilula occur at the base of the subzone, and several elements of the fauna have acmes in the top of the subzone, including: Sphenoceramus steenstrupi, Echinocorys spp. (tall, conical & large globose forms) and Baculites (Whitham, 1993).