Ostrea glabra
From the collection of Yale Peabody Museum. Free to download, adapt and use — no permission needed.
Geological context: Late Cretaceous, Fox Hills Fm. Collection locality: horizon OY (Oyster Shell Bed), upper Fox Hills, 3 mi S of Rattlesnake Butte, along Grand River, Corson County, South Dakota, USA. Collected by William L. Russell, 1926. IP number 70249; lot count 1; accn=IPA.07388; associatedwith=IP.340458,IP.340459,IP.340460,IP.340461,IP.340462,IP.340463,IP.340464,IP.340465,IP.340466,IP.340467,IP.340468,IP.340469,IP.340470,IP.340471,IP.340472,IP.340473,IP.340474,IP.340475,IP.340476,IP.340477,IP.340478,IP.340479,IP.340480,IP.340481,IP.340482,IP.340483,IP.340484,IP.340485,IP.340486,IP.340487,IP.340488,IP.340489,IP.340490,IP.340491,IP.340492,IP.340496,IP.340498,IP.340499,IP.340500,IP.340501,IP.340502,IP.340503,IP.340504,IP.340505,IP.340506,IP.340507,IP.340508,IP.340510,IP.340511,IP.340512,IP.340513,VP.059375,IP.340493,IP.340494,IP.340495,IP.340497,IP.340448,IP.340449,IP.340450,IP.340451,IP.340452,IP.340453,IP.340454,IP.340455,IP.340456,IP.340457.
Yale Peabody Museum’s own description