Concoidal rock fracture or shell imprint/fragment?

[MrR]

Greetings all. I just took a quick trip to visit the area where caldigger lost his life one year ago today. It was a sad visit to his beloved "Meg Hill" Bakersfield, but it was a little "respecting" I had to do. I didn't do much prospecting, but did spend a few minutes checking tailing piles. One thing I found and took a picture of but didn't take home, is something that resembles some sort of shellfish fossil. Either that or it's just a concoidal fracture of a mineral that's present. I just figured I'd get some opinions. As I said, I left it in Bakersfield, but thought it somewhat image-worthy. Thanks for any input. Cheers.

 

[Rockwood]

My respect. Sad news to me.

I think this looks like the surface of a more dimensional layered structure. Perhaps layered concretion.