Mantelliceras mantelli Zone

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Base: Base of the zone is mostly coincident with the base of the Chalk Group, except where earliest Cenomanian deposits comprise glauconitic sandstones (eg. locally in South-east Devon), where it is within the highest part of the Upper Greensand Formation.

Top: The top of the zone is immediately below the first appearance of Mantelliceras dixoni (Gale, 1995).

Range of Index species: Common in nominate zone, rare in overlying M. dixoni Zone (Wright & Kennedy, 1984).

Key Fauna:

Porifera: Stauronema carteri
Brachiopoda: Tropeothyris? carteri
Bivalvia: Aucellina spp.
Inoceramus anglicus
I. crippsi (locally abundant)
Ammonoidea: Hyphoplites spp.
Hypoturrilites gravesianus
Mantelliceras spp. (except M. dixoni)
Mariella spp.
Neostlingoceras carcitanense
Schloenbachia spp. (locally abundant)
Sharpeiceras spp.

Faunal abundance & preservation: Typically rich and phosphatised fauna near base of zone.

Bio-markers: (see under subzones)

Subzones: Mantelliceras saxbii

Sharpeiceras schlueteri

Neostlingoceras carcitanense

Age: Early Cenomanian