Brachiopod or maybe coral?

[Elkhorn]

Fossil found in Sierra County New Mexico in a wash located in the Monticello Canyon. Geological determination for this area is documented as Cretaceous - Mississippian.

We have found horn coral and some type of sea sediment rock in the wash. Would like to have an opinion on this fossil embedded in rock.

[Fossildude19]

Welcome to the Forum. 

Maybe a stromatolite, or some stromatoporoid? 

 

[Elkhorn]

I wondered if it might be stromatolite. I have resource material from the local library listing taxa reported from exposures west of the Rio Grande in the area where this was found.  Stromatolite was not listed.  Perhaps no stromatolite was discovered during the previous excavations. It does have some features that resemble strom.

[jikohr]

It kinda looks like the inarticulate brachiopod Orbiculoidea to me. At least in the first and third picture. Is the fossil just on the surface like a shell or does it go through the rock?

[supertramp]

8 hours ago, Elkhorn said:

I wondered if it might be stromatolite. I have resource material from the local library listing taxa reported from exposures west of the Rio Grande in the area where this was found.  Stromatolite was not listed.  Perhaps no stromatolite was discovered during the previous excavations. It does have some features that resemble strom.

Check for "oncolytic stromatolites" (maybe simply "oncolites" on your legends) 

ciao

[FranzBernhard]

9 hours ago, Fossildude19 said:

stromatolite, or some stromatoporoid?

 

9 hours ago, Elkhorn said:

stromatolite

 

1 hour ago, jikohr said:

inarticulate brachiopod Orbiculoidea

 

36 minutes ago, supertramp said:

"oncolytic stromatolites" (maybe simply "oncolites" on your legends)

That´s a tricky one!

@Elkhorn, are you able to discern if it is 3D or 2D? In other words, do you think its more like a 3D-object (something solid, sphere-like) or more like a 2D-object (something like a "shell")?

First pic looks more like a "shell", other pics more like a "sphere" in its widest sense. Tricky - but that´s good!

Franz Bernhard

[DPS Ammonite]

Unlikely to be a stromatoporoids as they mostly disappeared by the Mississippian. Algal structures such as oncolites and stromatolites are a good guess. What is the rock type? Limestone? Do you see any identifiable clasts or crystals in the rock? Are there any identifiable fossils in the rock other that the purported stromatolites? They also could be fragments of layered cave deposits.