Fossil Ammonites : General Information

Fossil Ammonites. First show in the late Silurian fossil record approx 400 Million Years ago. Most species of Ammonites lived between 240-64 Million years ago. All species of Ammonites died out by the end of the Cretaceous Period (65 Million Years Ago).<

Fossil Ammonite shells are usually planispirals, (coilded shells). As the Ammonite grew it added new and larger chambers to the open end of the shell. Fossil Ammonites moved by jet propulsion, similar to their nearest cephalopod living relative the Nautilus.

Ammonites appear on every continent and are therefore good index fossils, as it is often possible to link the rock layer in which they are found with particular geological time periods.

Fossil Ammonites are extinct marine animals which populated most pre-historic seas worldwide.

Ammonite Information : All species of Ammonites died out by the end of Cretaceous Period