Interesting rock or fossil?

[Ofap]

Found in a creek. Interesting textures and shapes for a rock. 

 

[Fossildude19]

Looks like conchoidal fractures in a rock, to me.

[Ofap]

9 hours ago, Fossildude19 said:

Looks like conchoidal fractures in a rock, to me.

Yes, it is conchoidal shaped but I would expect a smooth surface from a conchoidal fracture. It is difficult to tell from photos but the surface is textured and the only smooth surface is at the end of the “stumped” piece that protrudes the rock. 

[Fossildude19]

The stump is either a nodule/concretion,  or a mineral vein that runs through the rock. The entire piece is extensively weathered.

I see no bone texture, no bilateral symmetry, and no bone morphology.

Interesting geologic oddity, I would say.

[Plantguy]

I think its a rock as well. Initially thought maybe it could be some cetacean bulla as they tend to fracture like that.

 

The circular ring makes me wonder whats going on there...That ring with the internally radiating pattern almost looks like cross sections of belemnites I have but maybe

its purely mineral.

What age rock could this be from? I dont know the geology there...did some collecting in Charles county 50 years ago but that seemed to be Paleozoic aged gravels and critters where I was...

Regards, Chris