This picture shows Emericeras emerci (large spiral ammonite), Hamulina (shaped like a paperclip), Acrioceras (smaller version of Hamulina) and Costidiscus, the more familiar disc-shaped ammonite. These date to approximately 125 million years old in the Lower Cretaceous and were found at Alpes de Hautes Provence in France. They demonstrate quite how varied the ammonite form became.
Photo credit to Michael Schmidt.
