undet. Scaphitidae
From the collection of Yale Peabody Museum. Free to download, adapt and use — no permission needed.
Geological context: Late Cretaceous, Fox Hills Fm, lower Trail City Mbr. Collection locality: float, butte-like toe of SE-trending spur and adjoining outcrops and float areas, "Happy Hill", SE of Bench Mark Church, and about 6 mi WSW of Little Eagle, Corson County, South Dakota, USA. Collected by Karl M. Waage, 1959. IP number 316613; lot count 1; taphonomy=concretion; accn=IPA.07048; associatedwith=on same slab: IP.316613,IP.316617,IP.316618,IP.316619,IP.316620,IP.316621,IP.316622,IP.316624,IP.316625,IP.316626,IP.316627,IP.316628,IP.316629,IP.316630,IP.316631,IP.316632,IP.316636,IP.316637,IP.316639,IP.316640,IP.316642,IP.316643,IP.316644,IP.316638,IP.316633,IP.316614,IP.316615,IP.316616,IP.316623,IP.316634,IP.316635,IP.316641.
Yale Peabody Museum’s own description