Genuine Orthoceras Plate, Two Species

Two orthoceras fossils were found in a sea-bed matrix. Orthoceras ("straight horn") had a slender, elongated shell, with the middle of the body chamber transversely constricted, and a subcentral orthochoanitic siphuncle. The surface is ornamented by a network of fine lirae. 250 to 750 million years ago, the orthoceras mollusk lived in abundance during the Paleozoic Era. Orthoceras is a member of the class Cephalopoda and is closely related to the extinct giant Cephalopod and present-day chambered nautilus.