Pelecypods in limestone are fairly uncommonly preserved but I do have two examples that I've found in the Kalkberg Limestone near Schohaire. The first is what I believe is an Actinopteria communis based on the radial rays that decorate the shell surface and the "ear" that is typical of the Pterineidae. The shell is incomplete so I don't have too much more detail to work with.
The other is a rough cast that has the shape of a pelecypod but no other diagnostic details that would help to identify it.
The Kalkberg formation is Devonian in age (Lockhovian to Pragian stage).