Hello, friends.
I received some crumbly rocks, that are principally crinoidal limestone chunks from Rattvik, Dalarna County, Sweden from @Kasia
They are Late Ordovician in age, probably Boda Limestone, and when I boshed them I uncovered three brachiopods and this little specimen that I think is a bivalve.
I'm leaning towards Ctenodonta, but I don't know my bivalves very well, so I am asking for help. It's 8 mm wide at it's widest point.
Thank you very much for looking and elbow bumps for any suggestions.
Tim @Fossildude19?