Vertebrae or Concretions?

[gdsfossil]

Still learning my formations.  Found these close to the bottom of the Dakota Sandstone formation in Kansas.  

[Plantguy]

Looks to be either a fragmented cobble which has come apart (see arrows I added in your picture showing pieces shed from it) or perhaps a concretion. 

Seems to show lots of finer grained material all around it of different sizes as well. Are those all surface rocks or are they/some embedded in a matrix/the formation? Is that a conglomerate? Did you collect any concretions from this area? Any have fossils? I bought a couple concretions awhile back that had some very nice plant fossils....

 

This article discusses a basal conglomerate in Kansas

1 January 2007The Cretaceous basal conglomerate in Kansas

Daniel F. Merriam

Author Affiliations +

Transactions of the Kansas Academy of Science, 110(3):179-186 (2007). https://doi.org/10.1660/0022-8443(2007)110[179:TCBCIK]2.0.CO;2

 

https://bioone.org/journals/transactions-of-the-kansas-academy-of-science/volume-110/issue-3/0022-8443(2007)110[179%3ATCBCIK]2.0.CO%3B2/The-Cretaceous-basal-conglomerate-in-Kansas/10.1660/0022-8443(2007)110[179:TCBCIK]2.0.CO;2.full

 

Regards, Chris 

Edited December 5, 2020 by Plantguy
added photo

[LordTrilobite]

Looks a bit lumpy. Which makes me think these are not bones. But bones can often have concretions on them. Sometimes entirely enclosing them. Closeups would be helpful. The best way to tell is if you can find a broken piece. In a cross section you'll see bone structure if it's really bone.

[ParkerPaleo]

+1 for looking at a cross section of any nodule.  I worked on the Silvisaurus skull from the Dakota sandstone when I was at KU.  It definitely had a concretion (with lots of iron) around it.