orthoceras nautilus fossil is a genus of extinct nautiloid cephalopod restricted to middle ordovician aged marine limestones of

ancient animal archeology background baltic biology cephalopod closeup detail devonian dinosaur extinct fish fossil geology gray historical isolated jurassic macro mineral mollusc museum nature nautilus old orthoceras paleontology pattern period permian petrified polish prehistoric rock science sea sharp shell skeleton specimen squid stone sweden texture trilobite vintage white wildlife zoology