undet. Bivalvia

Geological context: Late Cretaceous, Marias River Sh, Kevin Mbr. Collection locality: lower of 2 limestone concretion layers in lower part of Kevin, N bank of Marias River, along US Rt 15, & about 6.5 mi SSW of Shelby, Toole County, Montana, USA. Collected by Neil H. Landman, Susan M. Kidwell, 1978. IP number 390723; lot count 1; accn=IPA.07111; associatedwith=on same slab: IP.852216,IP.851941,IP.851942,IP.851943,IP.851944,IP.851945,IP.851946,IP.851947,IP.852005,IP.851952,IP.851953,IP.851954,IP.852011,IP.852012,IP.852013,IP.852014,IP.852015,IP.852016,IP.852017,IP.852018,IP.851979,IP.851980,IP.851981,IP.851982,IP.852023,IP.852024,IP.852025,IP.852022,IP.851983,IP.851984,IP.851985,IP.851986,IP.852026,IP.852027,IP.852028,IP.852029,IP.852030,IP.852031,IP.852032,IP.851987,IP.851988,IP.851989,IP.852033,IP.851990,IP.851991,IP.851992,IP.851993,IP.851994,IP.851995,IP.851996,IP.851997,IP.851998,IP.851999,IP.852000,IP.852001,IP.852002,IP.852003,IP.852034,IP.852035,IP.852036,IP.852037,IP.852038,IP.