Eatonia medialis is a small brachiopod that has a relatively low profile to it's shell. The brachial valve is round and convex but not arched very high. There is a low profile ridge with three or four plications which corresponds to a shallow sulcus on the pedicle valve. The pedicle valve is slightly convex near the umbo, concave at the sulcus and flat along the margins. The specimen below was found in the Kalkberg Limestone near Shoharie, NY (Devonian, Lockhovian to Pragian stage).
Compare this specimen to one I found in the Licking Creek formation of Virginia which is equivalent in age to the Kalkberg formation of New York.