NJ Cretaceous stream joint bone or just concretion?

[Fishinfossil]

This just looked bizarre compared to any other concretions with such smoothness and the perfectly scalloped out area. Could it be dino bone of some sort?

 

 

 

?

[Rockwood]

Sorry. The look is of fracturing and weathering not bone.

[val horn]

I am not sure what to make of it,  The shape looks alot like a navicular bone, but rockwood is correct in that I dont see bone texture.  Maybe @Shellseeker or @Harry Pristis will have a more definitive opinion.

[pachy-pleuro-whatnot-odon]

Neither internal structure nor external surface look like bone to me... Rather, the ripples on the surface suggest a cryptocrystalline rock.

[Fishinfossil]

Thanks for all your input.