(Gym leaders theme here, not mine)

Dane

Team:
Baltoy (20): Psybeam, Mud-Slap, Rapid Spin, Rock Tomb

Phanpy (20): Defense curl, Rollout, Hidden Power, Body slam

Diglett (20): Bulldoze, Sucker punch, Sand attack, astonish

Hippoptas (20): Sand tomb, Crunch, Yawn, Body slam

Garglittle (20): Wing attack, magnitude, screech, scratch

Sandslash (23): Pin missle, Rollout, Dig, Metal claw

Rewards when you beat him: The mountain charm, TM for Earthquake, some ingredients, a fossil of choice, and a pokejob

The pokejob he offers is a fossil hunting expedition, which may allow your pokemon to gather fossils from out of regions.