Discoscaphites conradi w/ Negative

Hoploscaphites nicolletii Zone,

Trail City Member, Fox Hills Formation 

Upper Maastrichtian, Late Cretaceous 

South Dakota, USA

Fox Hills Formation Member, Zone and ammonite fauna

~ 66.5 MY

Trail City Member

upper Hoploscaphites nicolletii Range Zone

Protocardia-Oxytoma Assemblage Zone (also known as the transitional stage): Baculites larsoni, Discoscaphites conradi, D. gulosus, D. sp. cf. D. gulosus, D. rossae, Hoploscaphites nicolletii, H. spedeni, H. nebrascensis, Sphenodiscus beecheri, S. sp.

Upper nicolletii Assemblage Zone: Discoscaphites conradi, D. sp. cf. D. gulosus, Hoploscaphites nicolletii, Hoploscaphites spedeni, Sphenodiscus sp. (in pre 1996 publications called S. lenticularis), Trachybaculites columna