Devonian Period- C. 460 Million Years Old This plate contains one specimen of Orthoceras, which have been polished to reveal the inner segmented chambers of the shell. Fossils known as orthoceras, are extinct, nautiloid cephalopods, meaning “Straight Horn”, that lived more than 400 million years ago. Belemnites and Squids belong to a diverse group of cephalopods, characterized by an internal, long, straight, conical chambered shell enclosed entirely by soft muscular tissues. Cephalopods lived inside of their shell and had tentacles used to grab food and used jet propulsion, squirting water to move. Nice example with good detail. Matrix: 140mm x 213mm approx Orthocerus: 85mm to 140mm length approx