Rock.
-Geodude
-Onix
-Cranidos
Geodude is a Rock/Ground Type, as is Onix. Cranidos is a pure Rock type.
where can i find the second gym in Pokemon platinum
In Pokémon Platinum, the 6th Gym Leader, Byron has Steel-type Pokémon. The Steel-type Pokémon that he has during the first match until you beat him are Magneton, Steelix and Bastiodon.
You can use the GTS in Pokemon Platinum after you get the first gym badge from the Oreburgh City gym.
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by beating the gym leader
The 6th Gym Leader in Pokemon Platinum is Byron in Canalave City. He specializes in Steel-type Pokemon and has a Steel based Gym that looks like a construction site.
Oreburgh city.
Get the first gym badge
first you pass the first five gyms then you either get your best fire type Pokemon or fighting or ground they are the most effective against steel type Pokemon then you pass it.
None of the gym leaders use Flying-type pokemon. If you want to face a Flying-type gym, you can battle against Winona in Ruby, Sapphire, Emerald, and the ORAS remakes. Sheβs located on the southwestern side of Fortree.
easy battle the ghost type gym
Roark, a Rock-type specializing Gym Leader, can be found in Oreburgh City (just like in Diamond and Pearl).