Please help ID Lower Ordovician fossil.

[AJ58]

This fossil was found in Northeast Arkansas.Sandy wash.Lower Ordovician.

This fossil may not be common in this area it's the only one I have ever found.Thanks.  

 

 

[ynot]

Steinkern of a mollusc, not sure what mollusc though.

[AJ58]

Well I was hoping for something a little more unique than a steinkern.It looks like I have one half of one.I don't suppose it might be a Monoplacophora?

[ynot]

Sorry, I can not help any further on this one.

[BobWill]

It looks a bit like a Platyceras but I don't think they were around before the Silurian.

[AJ58]

How about Proteroconus eminense?

[Fossildude19]

Maybe a rostroconch? 

[minnbuckeye]

15 hours ago, ynot said:

Steinkern of a mollusc

 

Agree completely! Here is an example showing how different the Steinkern looks from the actual outer shell. Hence ID is difficult unless one knows the local species that exists in the area. And then, it is likely an educated guess vs a true guess.

 

 

Fig. 7  A different view of the Museum fossil, showing remnants of its actual shell, adhering to the “Steinkern” of the body-chamber. 

[AJ58]

I do agree that this is a Steinkern.Thanks for the ID. 

[Herb]

13 hours ago, AJ58 said:

Monoplacophora?

that would be my guess also