Question

What's the difference between Root Fossil and Claw Fossil?

Answer 1

• Root Fossil becomes a Lileep.
• Claw Fossil becomes an Anorith.

These Pokemon can be resurrected from the Fossils at the Devon Corporation building in Rustboro City.

Source

Answer 2

The root fossil and claw fossil revive to pokemon. The root revives Lileep and the Claw fossil revives Anorith. Take them to the 2nd floor of the Devon Corp building in Rustboro City. The man near the back right will tell you he can revive them. Give it to him, walk around for a while, and you have your new Pokemon.