How do get cradily in Pokemon ruby?

When in the desert, search for the fossils. when you find them, choose the "Root fossil", NOT the "Claw fossil". then go to the Devon corp. building in rustboro city. In the second floor, talk to the guy to the lower right. then answer "yes" on his question. go leave the building, make room for an extra Pokemon, and go back to the guy in the building. he will give you a lvl. 20 Lileep. Train him to lvl. 40, and he will evolve into Cradily.