This is a pretty decent gastropod specimen from the Panther Mountain formation (Devonian, Givetian stage) at Cole Hill, NY. It's a Bembexia sulcomarginata and retains a little of the original shell texture. The curved lines that are perpendicular to the shell spiral are key to identifying this species. Despite the presence of the shell texture, this is still considered a steinkern (or cast) of the specimen. It has a nice three dimensional shape and is missing just the tip of the spiral.
I've also found this genus in the Needmore Shale of Pennsylvania.