Unknown Potential Mollusk Fossil

[bencoulter]

Recently found this fossil in Capitola Beach, California. I found an abundance of fossilized shells in the area, but this one looked dissimilar. Anyways, is it possible that this is just a disfigured shell? Or is it something else? Thanks for your time! 

[Rockwood]

It's not at all clear, but you might consider the shape of an isognomon hinge.