Wow, the great finds of 2016 keep coming. Here is rare fossil find in that it is an intact Myalina clam fossil. One can still see some of the growth layers on the shell. Usually one only comes across one side of the shell.
It was found in the Edwardsville Formation of Floyd County, Indiana, USA. The fossil dates to the lower Carboniferous (Mississippian) Period. This next picture of one side of the shell is interesting in that it might the remains of a coral or bryozoan that attached to the exterior.