Mineral Deposits or Fossils

[Rockpit]

I found some already opened nodules that I cleaned up.  I wasn't sure if these were fossils or just mineral deposits. 

 

 

[Scylla]

Probably concretions but where are they from?

[Fossildude19]

6 hours ago, Scylla said:

Probably concretions but where are they from?

Hey Gus,

Rockpit mentions Mazon Creek in the tags. (yeah,  ... I forget to look there, too!  ) 

These look like mineral stained concretions, to me. 

But I have a hard time making anything out of most Mazon nodules.   

There are very frequently duds, with no fossils, ... from what I have learned here on the Forum. 

 

@fossilized6s   @RCFossils

 

Regards,

[Scylla]

But if it is Mazon creek, I would wait until a Mazon expert chimes in on it. Some of those look like a smudge and end up being a jellyfish or something.

[abyssunder]

I'm no expert in the Mazon Creek fauna and flora, but for future reference I'll put here a link to a useful document, which explains a lot of things related to the M.C. nodules/concretions.

Fernandes, Andrea S. 2012. A geobiological investigation of the Mazon Creek concretions of northeastern Illinois, mechanisms of formation and diagenesis. Electronic Thesis and Dissertation Repository. Paper 398.

 

I'm wondering if couldn't be something like Lascoa mesostaurata, or maybe Essexella asherae preserved in the matrix.

(I'm referring to the second specimen.)

[fossilized6s]

Unfortunately these look like simple mineral staining to me. 

[Rockpit]

Thanks for all your input.  I thought they were probably just stains but then I saw some seed (first picture) and horseshoe crab (second) pictures online so I didn't know if that would match.  I've been trying to use Richardson's guide but I'm having a hard time comparing what I've found to the black and white pictures.  I also don't know if I should say what I think they could be because I don't want to plant ideas in anyone's mind.  The longer I look at things the more things I do and do not see.  It makes me bug eyed.