What have I got in this rock?

[njguy]

I originally posted this under what is it, but suggestions lead me to repost this here with the hope of getting better specifity and value of such an object. I found this on a beach at the jersey shore. It's about 3 1/2" width height and depth. I can't tell if it's a fossil or a cement formation that wrapped around a couple of crabs. The stone is hard and smooth like a real rock though. It doesn't rub away like cement should. But I'm no expert on cements. The creature features feel hard as stone too. I'd appreciate your thoughts.

[SnakemanBill]

Looks like you found yourself a nice crab fossil in concretion.

[Goldmanford]

Looks like you found yourself a nice crab fossil in concretion.

My opinion, too! Nice find! Don't know value though.

[njguy]

Any idea as to the age and value of such an object?

[LanceHall]

Great fossil crab!

[njguy]

So what kind of crab has a lobster like tail/flipper? I can't seem to find one on record. The ones I am finding have horizontal lines in the female's flippers (if looking at it with a top view front to back) These at the same view are vertical in that same orientation. I'm sure this isn't a new or unknown species so any extra eyes on this would be helpful. Thanks.

[lordpiney]

did you find it on Sandy Hook? ive read of others finding smiler fossils there. there's a very good chance that it is a lobster. check this out.
http://www.geo.hunter.cuny.edu/bight/fossil.html