Ammonites were shelled cephalopods that lived during the Jurassic and Cretaceous periods about 201-66 million years ago. Its believed the asteroid that hit the Earth 66 million years ago, ending the age of the dinosaur also caused ammonites to become extinct while other cephalopods like nautiluses survived. Their distinctive coiled shells are made of calcium carbonate and divided into chambers separated by thin walls called septa. Ammonites lived in a variety of marine habitats from shallow coastal waters to deep-sea environments. They fed on small fish, crustaceans, and other invertebrates. The name “Ammonite” is named after the Egyptian god Amun, who is often depicted as a ram with twisted horns.