Ironstone fossil

[Lone Hunter]

I could probably fill the back of a pickup truck with ironstone I've picked up for closer inspection because it looked like it may have fossil possibilities, have only found a few and this is one. Found in Grayson formation Tarrant co, first thought was ammonite impression but there's a second faint impression on opposite side that doesn't fit with that and the outline isn't right, or am I not imagining the overall shape correctly? 

[Rockwood]

That looks like a couple partial brachiopods molds.

Ties me for finds the last few days if it is. 

[Lone Hunter]

Might explain why I don't recognize it, I have yet to find any Brachiopods from there so not familiar with the shells.

[ClearLake]

Cretaceous brachiopods in north Texas are pretty limited with Kingena wacoensis being one of the few found and it is smooth.  Imprints of a bivalve (or two) are probably much more likely in my opinion.

[Lone Hunter]

5 hours ago, ClearLake said:

Cretaceous brachiopods in north Texas are pretty limited with Kingena wacoensis being one of the few found and it is smooth.  Imprints of a bivalve (or two) are probably much more likely in my opinion.

Thank you and I have to agree,  I've only found 2, this being one, I think, it came from Grayson also but since it's missing outer shell so I didn't know how to ID it.  Could this be what you referenced? 

[ClearLake]

9 hours ago, Lone Hunter said:

Could this be what you referenced? 

Yes, it looks like it to me.  Double check by flipping it over and see if the beak overhangs a bit and maybe even see the round pedicle opening.  This type of brachiopod is why they were often called "lamp shells", they look like the the old oil lamps (think Aladdin- haha).  

[Lone Hunter]

Yep that describes it exactly, thanks!  Always wondered what was the lamp shell term now I know.