Can anyone identify these bivalves?

[Cgs928]

Hello all,

Could anyone confirm or refute the identifications that I assigned to these?

[Fossildude19]

Hmm. Where were these found?

 

I'm not seeing any diagnostice features on these.  

Can we get pictures of the other sides?

 

Cropped and brightened:

 

 

     

[Cgs928]

These are from the Glen Rose Formation in Spring Branch, Texas. Sadly these seem to both be molds and lacking any shell characteristics. 

[DPS Ammonite]

The first bivalve is probably not Palaeoneila oweni because it is too elongated. Palaeoneila oweni occurs in the Pennsylvanian rocks of Texas (Jacksboro) and not in the Cretaceous. I agree with Cyprimeria sp. for the second. However, I do not think that Cyprimeria occur in the 110 mya Glen Rose Formation since Cyprimeria first appeared about 100 million years ago.

 

EDIT: Other sources indicate that Cyprimeria occur in Walnut and Goodland Formation that are 105-108 mya. An expert in Texas fossils will have to ID species and let us know if they can be found in the Glen Rose Fm.