Devonochonetes coronatus is a species that I know well from Givetian aged deposits in Pennsylvania and New York. Below is a specimen from the Silica Shale (Devonian, Givetian stage) near Sylvania, OH. It follows the form that I have used in the past to ID similar shells: Large size, rectangular shape, 1 valve covex while the other is concave. The specimen below has partially been replaced with Pyrite (darker areas) which is why it has a mottled appearance.
Compare this to specimens I've found in the Centerfield mbr. of the Ludlowville Formation of New York and the Mahantango Formation of Pennsylvania.