Lower Mississippian bi-valve id help

[JimB88]

I need help with this one. Ive been searching the internet; but there is precious little works on Lower Mississippian bivalves. So I thought Id turn to you guys either for an id or to point me in the direction of an expert in such things.

Its from the lower Mississipian epoch of the Carboniferous. The Fort Payne Chert, the black shale member (not sure if that has a name.)

 

 

 

Its fairly large for a bivalve from this time period.

 

Im not sure if they are related but Ive also been finding these. I believe its also a bivalve but I havnt found more than one valve. They are a lot more common than the bigger one.

With the similar concentric ribs, they may be younger versions; though the overall difference in shape makes me doubt it.

 

 

 

I appreciate any help you can give me.

[grandpa]

Are you certain of the age?  This sure looks like an inoceramid clam (Jurassic - Cretaceous).

[JimB88]

Just now, grandpa said:

Are you certain of the age?  This sure looks like an inoceramid clam (Jurassic - Cretaceous).

Yep, Its from TN near the border with KY, where there is no Mezozoic rocks. Plus Ive found some of the usual suspects from the Fort Payne in that layer (blastoids and trilos.)