Unknown Circular Upper Ordovician Fossil

[Kyleigh Hope]

Hello, this slab is from the Kope Formation, particularly Upper Alexandria sub-member within Delhi Township, Ohio.

 

I am unsure if these rounded "structures" are bryozoans, echinoderms, or brachiopods, but i'm leaning more toward bryozoans.

 

Fauna on the slab include:

-Cincinnaticrinus, Ectenocrinus

-Retrosirostra OR Dalmanella (hard to distinguish)

-Bythopora

-Isotelus, Flexicalymene

-Ambonychia

 

If anyone has an idea as to what the round objects are, please comment! Thank you!

 

EDIT: I now believe these are individual cephalopod chambers that were filled with hash. I credit a fellow UC student!!! Now I wonder if anyone else thinks similarly.

Edited November 6, 2022 by Kyleigh Hope
Found possible ID but want more confirmation.

[Rockwood]

6 hours ago, Kyleigh Hope said:

I now believe these are individual cephalopod chambers that were filled with hash. I credit a fellow UC student!!! Now I wonder if anyone else thinks similarly.

The shape doesn't present a lot of hard evidence, but I can't think of another tube shape from the time period that seems more likely. The darker material that lines the inside could be cameral deposits ?