No idea

[grg1109]

I've found this...I've looked through my middle devonian books under Gastropod, Ammonite, Bivalve, Brachiopod...can't find it under any of them.   Pretty sure it's a mud mold...but, not 100%.   Comes from the Kashong Member, Hamilton Group, Middle Devonian, Seneca Cnty, NYS.

Thanks

Greg

Edited October 6, 2021 by grg1109

[ClearLake]

Don't you think it is the bivalve Grammysioidea?  It is both valves but the edges might be broken off (hard to tell in this single picture).  Probably is an internal mold.  The two beaks are in the lower center part of the picture.  Very neat looking.

[Fossildude19]

From "Devonian Paleontology of New York, by David Linsley, 1994"