Pokémon Ruby and Sapphire/Route 111

Use the Go-Goggles to explore the desert of Route 111. In the northeast corner of the desert is a pair of fossils. Grab one of them (the other will sink). Take it to the Devon Corp and the researcher will determine it is a Pokémon. The Root Fossil turns into a Lileep, while the Claw Fossil turns into an Anorith.

At the southern tip of the desert is TM37 (Sandstorm).