After a dinosaur died, it had to be buried underground.The dinosaur was covered with soil or sand so the bones did not rot.
Over time, layers of sediment piled up on top of the dead dinosaur.
These sediments put pressure on the dinosaur's bones.
This pressure caused them to gradually harden.
After a dinosaur died, it had to be buried underground.
The dinosaur was covered with soil or sand so the bones did not rot.
Over time, layers of sediment piled up on top of the dead dinosaur.
These sediments put pressure on the dinosaur's bones.
This pressure caused them to gradually harden.