Side A: Around 1867, along the shale cliffs of the lakeshore of Sheffield Lake, Jay Terrell found fossils of a “terrible fish” later named in his honor as Dinichthys Terrelli. This animal, now known as Dunkleosteus terrelli, was a massive arthrodire (an extinct, joint-necked, armor-plated fish) that lived in the Devonian sea, which covered much of eastern North America some 354-364 million years ago. Dunkleosteus was armed with an incredible set of shearing jaws and was clearly the top marine predator in the Devonian Period (the “Age of Fishes”).