Silurian mollusk

[aek]

What type of mollusk is this? Oyster? Bivalve?Internal mold. Silurian Thanks for any help.

[RuMert]

Brachiopod?

[Misha]

Views from other angles and a scale would be very helpful

[aek]

@Misha @RuMert I don't think it's a brachiopod. Here's a couple more photos.

[RuMert]

Isn't it an internal mold with brachidium imprints? Just a guess

[aek]

@RuMertmAybe you're right. . @Tidgy's Dad do you have any idea if this is a brachipod or oyster internal mold?

[Tidgy's Dad]

Judging from the shape of the beak, what seem to be muscle scars and their position and shape, and the dentition, which looks taxodont to me, I'd say bivalve. 

[aek]

@Tidgy's Dad thank you!

[TqB]

I agree with @Tidgy's Dad, bivalve internal mould with very nice dentition.

[Kentuckiana Mike]

It reminds me of a Cretaceous Period Pterotrigonia thoracica pelecypod. I do not know if it had an ancestor that existed in the Silurian Period.