Ammonites are tiny shelled creatures that scientists say lived in the oceans, billions of years ago. Considering that no one has ever seen one alive, we think we know a lot about them.

Why do scientists think they existed? Ammonites were once plentiful, say scientists, and we know this because their fossils can be found in many places. Although ammonites are sea-creatures, the sites where the fossils are found are no longer seas. We now find them in rocks!

Denise Balmer is a geologist and she visited Year 7 at Trevelyan School to explain what else ammonite fossils can tell us about the past.