Sphenoceramus (Inoceramus) lingua Zone
This zone is only currently used in northern England (Whitham, 1991) because the standard zonal equivalents (Offaster pilula Zone & ? G. quadrata Zone pars) cannot be recognised.
Base: The base of the zone is placed at marl SY23 of Whitham (1993).
Top: The I. lingua Zone is the youngest exposed zone in the Chalk Group of northern England, and thus its top is undefined.
Range of index species: The index ranges from within the M. testudinarius Zone, through the U. anglicus Zone, to the top of the nominate zone (Whitham, 1993; Mitchell, 1995).
|Porifera:||locally abundant & well preserved sponges|
|Sphenoceramus (Inoceramus) lingua|
Faunal abundance & preservation: The zone is quite richly fossiliferous, and there are local concentrations of sponges, echinoids and bivalves.
Bio-markers: In the lower part of the zone Sphenoceramus pinniformis is common, with acmes of the oyster Pseudoperna boucheroni and large domed Echinocorys associated with a rich fauna of well preserved sponges, forming the famous Flamborough Sponge Beds (Whitham, 1993). In the middle of the zone is a further, un-named, sponge bed, above which Sphenoceramus patootensis occurs, with rare Offaster pilula, and pyramidate morphotypes of Echinocorys (Whitham, 1993). In the top of the zone, Discoscaphites binodosus occurs with Baculites, Micraster glyphus, M. schroederi, Sphenoceramus steenstrupi and conical and globose morphotypes of Echinocorys (Whitham, 1993).
Subzones: Discoscaphites binodosus Subzone