Orthoceras

The fossils commonly known as Orthoceras are extinct "straight-shelled" cephalopods that lived during the Upper Devonian period around 370 million ...

The fossils commonly known as Orthoceras are extinct "straight-shelled" cephalopods that lived during the Upper Devonian period around 370 million ...

Orthoceras was an ancient cephalopod that lived about 370 million years ago. The name means straight horn, referring to the characteristic long, st...

Ammonites first appeared about 240 million years ago, though they descended from straight-shelled cephalopods called bacrites that date back to the...