undet. Mollusca
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: concs., south-facing bluff just E of Whitehorse-Timber Lake road, and 6 mi NW of Whitehorse, Dewey County, South Dakota, USA. Collected by Karl M. Waage, 1957. IP number 317524; lot count 1; taphonomy=concretion; accn=IPA.07048; associatedwith=on same slab: IP.317524,IP.317556,IP.317557,IP.317558,IP.317559,IP.317560,IP.317561,IP.317562,IP.317563,IP.317564,IP.317565,IP.317566,IP.317567,IP.317568,IP.317569,IP.317570,IP.317571,IP.317572,IP.317525,IP.317526,IP.317527,IP.317528,IP.317529,IP.317530,IP.317531,IP.317532,IP.317533,IP.317534,IP.317535,IP.317536,IP.317537,IP.317538,IP.317539,IP.317540,IP.317541,IP.317542,IP.317543,IP.317544,IP.317545,IP.317546,IP.317547,IP.317548,IP.317549,IP.317550,IP.317551,IP.317552,IP.317553,IP.317554,IP.317555.
Yale Peabody Museum’s own description