Ammonite

Ammonites lived during the periods of Earth history known as the Jurassic and Cretaceous. Together, these represent a time interval of about 140 million years.Ammonites are the extinct relatives of sea creatures such as the modern nautilus. The Jurassic Period began about 201 million years ago and the Cretaceous Period ended about 66 million years ago. The ammonites became extinct at the end of the Cretaceous, at roughly the same time as the dinosaurs disappeared. However, we know a lot about them because they are commonly found as fossils formed when the remains or traces of the animal became buried by sediments that later solidified into rock.