Limestone Pennsylvanian Mystery

[Lucid_Bot]

I have no idea what this is. It's unlike anything I have found. I split it out of Brush Creek Limestone today. Pennsylvanian Period, Glenshaw Formation. It's about 25 cm in circumference at the base. I would guess cephalopod, but it's much bigger than one's I've previously found. Help is appreciated, thanks!

Edited May 6, 2023 by Lucid_Bot
forgot formation

[Lucid_Bot]

This does look a bit like Glikmanius sp. (picture from @cngodles) :

Edit: I see this specimen is much smaller to mine.

Edited May 7, 2023 by Lucid_Bot

[cngodles]

The scale bar on my tooth there is 5 mm. I suspect it’s the steinkern of the cephalopod Poterioceras curtum, they grew to very large sizes and had a cone-like shape. That might be a siphuncle opening inside the smaller oval. It would be a smaller circular feature.

 

This is one below, but it’s skewed and smashed.

 

https://fossil.15656.com/catalog/specimen/CG-0500

Edited May 9, 2023 by cngodles

[Lucid_Bot]

9 hours ago, cngodles said:

I suspect it’s the steinkern of the cephalopod Poterioceras curtum, they grew to very large sizes and had a cone-link shape.

 

I think your right. It looks extremely similar to Poterioceras curtum, conical and large. Thank you for all your help.