The complete Pokemon RBY pokedex, part 11

Pokémon Name: Rhyhorn
Type: Ground / Rock
Classification: Spikes Pokemon
Pokédex Number: 111
Ability: Rock Head and Lightningrod
Dream World ability: Reckless
Useful Attacks: Take Down
Location Found:
Diamond/Pearl: Route 227, Stark Mountain
Platinum: Routes 214 and 227, Stark Mountain, Victory Road
HG/SS: Victory Road, Safari Zone (Savannah); Pokewalker - Volcano Path
Black: Trade, Poke Transfer
White: White Forest (resident required: Shane)

High on attack and defense, low on special stats and speed. Its late evolution makes way for an even more powerful creature though, so trainers who plan to stick with the game have a chance to nab Rhydon and Rhyperior.

Evolution: To Rhydon at 42