Orthoceras were an early relative of the Ammonite and a member of the Nautiloid family. Later varieties became coiled for buoyancy unlike the straight shell of the Orthoceras which sunk more easily. Orthoceras fossils are around 395 million years old and found in Morocco.
Each one is polished on the top, with a flat underside. You get one of these wonderous fossils, as photo is to show natural variation. These are the largest size we do, measuring approximately 65mm to 100mm long by 35mm to 50mm wide.