Description: This nodule contains the distinctive plates that composed the cephalic shield of Coccosteus, a Placoderm (armored fish) of the Devonian. This specimen comes from an old collection; the quarry was closed in 1972. Fossils of Coccosteus have been found in Europe and North America, primarily in freshwater deposits, with a maximum size of some 40 cm. They did not possess true teeth, but rather bony plates which were kept sharp by continual grinding of the upper and lower jaw plates against each other. The largest of the placoderms was Dunkleosteus, a monster at over 6 meters in length. The placoderms dominated the seas for some 60 million years before going extinct at the end of the Devonian.