Discoscaphites conradi half Natural, half Exposed Sutures

Hoploscaphites nicolletii Zone 

Trail City Member, Fox Hills Formation 

Upper Maastrichtian, Late Cretaceous 

South Dakota, USA

Fox Hills Formation Member, Zone and Ammonite Fauna

~ 69 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

lower Hoploscaphites nicolletii Range Zone

Limopsis-Gervillia Assemblage Zone: Discoscaphites conradi, Hoploscaphites nicolletii, H. spedeni, Sphenodiscus sp. (in older publications called S. lenticularis); equivalent to the upper Elk Butte Member of the Pierre Shale in north central SD where Discoscaphites and Sphenodiscus are extremely rare.

Lower nicolletii Assemblage Zone: Hoploscaphites nicolletii, H. spedeni