Calycoceras guerangeri Zone
Base: The base of the zone is immediately below the first appearance of the index species (Gale, 1995).
Top: The top of the zone is immediately above the last occurrence of the index species (Gale, 1995).
Range of index species: The zone is coincident with the total range of the index species (Gale, 1995).
|Bivalvia:||Amphidonte obliquatum (locally abundant)|
|Echinoidea:||Holaster spp. (thin-shelled, fragmentary species)|
Faunal abundance & preservation: The zone is typically sparsely fossiliferous, and the fauna often fragmentary and poorly preserved.
Bio-markers: The middle of the zone contains a widely developed acme of the oyster Amphidonte obliquatum (Gale et al., 1999).
Age: Late Cenomanian.