Help needed for a newbie

[Reascat]

Hi, this is my first post, so I hope I don’t omit any important information. My daughter has found this fossil at a quarry near Matlock in Derbyshire, UK, and we would love to know what it is! It’s 3.5 cm length, we were thinking it might be a bivalve but aren’t sure. Thanks so much in advance for your help! 

 

Sarah

[Ludwigia]

Any chance of getting a sharper photo? It's hard to make out any details.

[Reascat]

Any better?

[Fossildude19]

Welcome to the Forum.  

Can we get a size measurement on this item? 

 

Cropped, enlarged, brightened, and rotated:

  

 

 

My first thought was bivalve, but locals may have some more insight -  

 

@JohnBrewer   @TqB

 

[Reascat]

Thank you! It’s 3.5 cm in length 

[Mioplosus_Lover24]

 

Not a local, but looks kind-of like a gastropod cross-section as you can see some "chambers".

[Fossildude19]

I'm not seeing any chambers, but I do see growth lines, similar to some bivalves.   

 

Just found this online: 

 

[Ludwigia]

It really is hard to tell, but I'm leaning toward gastropod.

[TqB]

I'm pretty sure it's a bivalve. Identifying Carboniferous ones is a specialist task but it looks something like Posidoniella or Posidonia.

[Reascat]

Thanks so much everyone for your help.  Sadly the quarry she found the fossil in is now closed to the public as they are going to use the land to build a housing estate on it, it was full of fossils, we found lots of Crinoid stems and fossilised shells, such a shame!