undet. Ammonoidea
From the collection of Yale Peabody Museum. Free to download, adapt and use — no permission needed.
Geological context: Late Cretaceous, Fox Hills Fm, Trail City Mbr. Collection locality: float, 3 grassy knolls 1 mi W of McLaughlin-Little Eagle road, and 3.3 mi NNW of Little Eagle, Corson County, South Dakota, USA. Collected by James F. Mello, 1960. IP number 342947; lot count 1; taphonomy=concretion; accn=IPA.07048; associatedwith=IP.342949,IP.342950,IP.342951,IP.342952,IP.342954,IP.342966,IP.342967,IP.342969,IP.342977,IP.342978,IP.342983,IP.342985,IP.342994,IP.342991,IP.343003,IP.342948,IP.342953,IP.342955,IP.342956,IP.342957,IP.342958,IP.342959,IP.342960,IP.342961,IP.342962,IP.342963,IP.342964,IP.342965,IP.342968,IP.342970,IP.342971,IP.342972,IP.342973,IP.342974,IP.342975,IP.342976,IP.342979,IP.342980,IP.342981,IP.342982,IP.342984,IP.342986,IP.342987,IP.342988,IP.342989,IP.342990,IP.342992,IP.342993,IP.342995,IP.342996,IP.342997,IP.342998,IP.342999,IP.343000,IP.343001,IP.343002.
Yale Peabody Museum’s own description