Crab fossil maybe?

[water waders]

Hello!

My brother and I have gone to Big Brook in NJ a couple a times, and stumbled on this.

 

 

My brother is convinced it is a crab, while I am still on the fence about it.

I've done some searching online and never found any records of a whole crab shell, so it'll be nice to get some identification.

 

Thanks!

 

 

[ynot]

Welcome to TFF!

Looks like the internal cast of a clam shell.

These are called steinkerns.

[Ludwigia]

I agree with cast of a bivalve shell. Certainly not arthropod carapace, although it does have a similar shape at first glance.

[Rockwood]

I'm not sure, but the texture seems crabby to me.

Ghost shrimp claws from there sort of have a similar look. That is probably makes me think that.

[RJB]

Internal mold of clam.

 

RB

[water waders]

Thanks for all the help!

 

At least it wasn't just a rock haha