Sciponoceras gracile Zone

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This zone is only currently used in northern England (Whitham, 1991), and in some areas has in part been replaced by the standard ammonite zonal equivalents (= M. geslinianum & N. juddii zones) for this part of the Cenomanian (Gaunt et al., 1992).

Base: The base of the zone is the sub-Black Band (s.l.) erosion surface (Whitham, 1991).

Top: The top of the zone is placed at an un-named chalky marl, locally c. 0.5 m below the lowest acme of the inoceramid bivalve Mytiloides (Whitham, 1991).

Range of index species: The index was not recorded by Whitham (1991)

Key fauna:

Brachiopoda: Monticlarella jefferiesi
Orbirhynchia multicostata
O. wiesti
Bivalvia: Inoceramus pictus
Oxytoma seminudum
Belemnoidea: Praeactinocamax plenus
Vertebrata: fish debris

Faunal abundance & preservation: The zone is rather poorly fossiliferous, and the fauna of low diversity.

Bio-horizons: Praeactinocamax plenus occurs at two closely spaced horizons below the Black Band s.s., in the lower part of the zone (Wood & Mortimore, 1995).

Age: Late Cenomanian