Leptaena Brachiopod

UPDATE: I originally labeled this Megastrophia concava but Shamalama determined it was probably a Leptaena brachiopod instead.  After some more research, I agree.

Leptaena brachiopod found in the Jeffersonville Limestone of Clark County, Indiana.  This brachiopod existed in the Devonian Period.

Thanks to Mary Ann for letting me photograph it.