Specifically, members of the Maclurites family fossilized in the Middle-Upper Ordovician Valcour formation (c. 460 mya) that was once the tidal shoreline of proto-North-America.
My attempt to reconstruct Maclurites in yarn! The fleshy bit doesn’t smush into the shell quite as well as I’d like and there’s no foot to this gastropod, but I hope I correctly captured the scale, the chirality of the shell and operculum, and the characteristic flat bottom of the fossil genus.
