Hoploparia gabbi is a lobster that is found in the Navesink formation of New Jersey. I found it in the Ramanessin creek near Marlboro, NJ. This is only a partial fossil of the whole animal as it's missing the legs, claws and tail but it's still fairly rare to find even this much.
Ventral (top) surface
The Navesink was lain down in the latest Cretaceous (Masstrichtian stage) as a layer of sediment that was (at that time) moderately deep water.