Pewter City Gym
Description Of Pewter Gym:
The Pewter Gym is home to Leader Brock, a Rock-Type Pokemon User. His Gym is pretty basic, only having on trainer standing before him, and even this trainer can be bypassed by walking around him. If you do decide to battle this trainer as a warm-up to Brock, he has a Level 11 Diglett and Level 11 Sandshrew.
After defeating or bypassing this trainer, you can face Brock. Since he only carries around Rock-Type Pokemon, Brock will be a difficult battle because of their high defenses. However, Brock can be an easy defeat by using Water, Grass or Fighting Type Moves.
Brock's Pokemon: Level 12 Geodude & Level 14 Onix
After you defeat Brock, you'll receive the Boulder Badge and TM34 (Bide). You will also be allowed to use HM05 (Flash) outside of battle.