undet. Mollusca
From the collection of Yale Peabody Museum. Free to download, adapt and use — no permission needed.
Geological context: Late Cretaceous, Medicine Bow Fm. Collection locality: W of Rawlins, Wyoming, USA. IP number 316066; lot count 1; taphonomy=concretion; institutional specimen number 27763; accn=YPM.07580; associatedwith=on same slab: IP.316066,IP.316067,IP.316068,IP.316069,IP.316070,IP.316071,IP.316072,IP.316073,IP.316074,IP.316075,IP.316076,IP.316077,IP.316078,IP.316079,IP.316080,IP.316081,IP.316082,IP.316083,IP.316084,IP.316085,IP.316086,IP.316087,IP.316088,IP.316089,IP.316090,IP.316091,IP.316092,IP.316093,IP.316094,IP.316095,IP.316096,IP.316097,IP.316098,IP.316099,IP.316100,IP.316101,IP.316102,IP.316103,IP.316104,IP.316105,IP.316106,IP.316107,IP.316108,IP.316109,IP.316110,IP.316111,IP.316112,IP.316113,IP.316114,IP.316115,IP.316116,IP.316117,IP.316118,IP.316119,IP.316120,IP.316121,IP.316122,IP.316123,IP.316124.
Yale Peabody Museum’s own description