undet. Bivalvia
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: various layers in road cut on E side of spur and on W side of old US 12 about .75 mi S of intersection with Wakpala road, N side of hill with Ridgeview 1954 bench mark, and 4.5 mi S of Mahto, Corson County, South Dakota, USA. Collected by Karl M. Waage, George Colton, 1949. IP number 561360; lot count 1; taphonomy=concretion; accn=IPA.07048; associatedwith=on same slab: IP.561363,IP.561726,IP.561718,IP.561720,IP.561722,IP.561731,IP.561662,IP.561353,IP.561719,IP.561721,IP.561723,IP.561724,IP.561725,IP.561727,IP.561728,IP.561729,IP.561730,IP.561732,IP.561733.
Yale Peabody Museum’s own description