Oysters/clams Duck Creek/Fort Worth?

[Shaun-DFW Fossils]

I don’t find these too often, and rarely can they be extracted in a way that looks good (in my limited experience), but these two were found as shown already separated on all sides. The bigger one is REALLY big compared to those I usually find. I placed a smaller one found in the same spot right next to it for comparison. I tried to use Lance Halls northtexasfossils site to find something similar and there’s a Pennsylvanian specimen that sort of looks similar, but many of his pics aren’t loading properly so I don’t know if I overlooked a likely candidate. Any ideas? This is Tarrant county TX, a spot where I can find exposure of kiamichi clay and Fort Worth formation as well as duck creek. 

Edited November 25, 2023 by Shaun-DFW Fossils

[hadrosauridae]

Not oysters, those are Inoceramus clams.  Like you have seen, the actual shell is extremely thin and fragile, and rarely survives.  Most of the time all you find are the negative impressions, so to have some complete steinkerns of them is still a great find!

[DPS Ammonite]

Inoceramids. More research of form and knowledge of formation they are from is needed to see if these are Inoceramus or a sister genera.

You can see some of the circled shell on the internal molds. If you flip these pieces over and see an impression of the other shell of the animal then you have a steinkern.

[Shaun-DFW Fossils]

8 minutes ago, DPS Ammonite said:

Inoceramids. More research of form and knowledge of formation they are from is needed to see if these are Inoceramus or a sister genera.

You can see some of the circled shell on the internal molds. If you flip these pieces over and see an impression of the other shell of the animal then you have a steinkern.

 

8 minutes ago, DPS Ammonite said:

Inoceramids. More research of form and knowledge of formation they are from is needed to see if these are Inoceramus or a sister genera.

You can see some of the circled shell on the internal molds. If you flip these pieces over and see an impression of the other shell of the animal then you have a steinkern.

Thank you both for sharing the knowledge you’ve acquired! And for the correction, I hate when I get seemingly simple things wrong, but I’m learning more every day..