Bone or stone?

[Ruger9a]

Is this a bone or a stone?  It came from the Bone Beds of Shark Tooth Hill, Bakersfield, California.  Miocene.

[Rockwood]

It's not bone.

I think it could be calcareous algae though.

[JohnBrewer]

+1 for not bone

[Jdeutsch]

agree with Rockwood

Chlorellopsis

[caldigger]

It's the outer shell of a concretion.  The deposits are absolutely loaded with them.

Some but not most may contain a fossil bone as the nucleus.

I happened to break one open accessing an area and out popped a surprisingly well preserved vert. ( very rare to get one from a concretion in this good of shape I may add! ).

Usually the bone in these things turns to dust when exposed.

The majority of the concretions just contain clay balls in the center.

[Ruger9a]

Thanks guys.  I can pull another one from the unidentified draw. yes...…………..

[Ruger9a]

Caldigger, Love the vertebrate.  I don't seem to have that kind of luck. 

[MrR]

On 11/23/2019 at 8:37 AM, Ruger9a said:

Caldigger, Love the vertebrate.  I don't seem to have that kind of luck. 

 Ol' caldigger definitely has a bit of the luck. That said, he's also more like a human skip-loader than mere digger. He goes through a lot of material, but also has the know-how, perhaps instincts as well, to narrow down which is the proper material before he starts a-diggin'. Me, I just beat my head against walls of concretions, and such, hoping something interesting breaks loose. And all that does is compact the matrix even more to make the next guy's digging even harder, and an aching head for the drive home.