Orthoceras Fossils are a time capsule of an extinct marine animal from over 400 million years ago. They were a squid-like creature similar to the present day Chambered Nautilus. Instead of being spiraled as the Chambered Nautilus or the related fossil the ammonite they were straight and cone shaped. They are found from several inches long to over six feet long. They propelled themselves taking in water and then forcefully squirting the water out.