The Unova region seems to be a sort of parallel to the Kanto region. These games were the first since the original games to release Pokemon not related to any other previous generation. Also there are many different evolutionary lines in the newest generation games that are very similar to the ones native to Kanto, like Roggenrola and its evolutionary relatives being the Unova version of the Geodude line.
Roggenrola looks like a small rock with feet. It’s primarily colored blue, though has a yellow center that could be considered an eye. It has light brown feet and another rock the same color on top of its head. It appears to be based off from a geode, geographical rock formations that are normally made up of some sort of crystal surrounded in limestone, or other type of rock related to limestone. According to its pokedex entries, Roggenrola’s ear is a hexagonal shape. Because it was compressed underground, its body is as hard as steel. They were apparently discovered a hundred years in an earthquake fissure. Inside each one is an energy core. Roggenrola has the lowest special defense of any rock-type. Its name is most-likely a play on the term “rock and roll”.
Once Roggenrola reaches level 25, it evolves into Boldore. Boldore seems to be made up of many different bluish colored rocks that have coral colored crystals sticking out from them and shares a few characteristics (like its large ‘arms’) with crabs. According to its pokedex entries, when Boldore overflow with power, the orange crystals on its body glow. It looks for underground water in caves. It is said that because its energy was too great to be contained, the energy leaked and formed orange crystals. Boldore’s name appears to be a corruption of the word “boulder”, and seems to be a combination of the words ‘boulder’, ‘bold’ (for being outstanding and larger), and ‘ore’ (a type of rock that contains metals, which is most-likely a reference to its type).
Like the Geodude line, Boldore reaches its final form, Gigalith, through trade. It is the first and only rock-type Pokemon since Generation I to evolve through trade without any extra conditions. Gigalith, like its pre-evolution, seems to be made up of large slabs of bluish rocks. Crystals are buried in the rocks and it is suspected that Gigalith is based off from crystal formations. Unlike its pre-evolutions, though, Gigalith has four leg-like limbs. Its pokedex entries state that the solar energy absorbed by its body’s orange crystals is magnified internally and fired from its mouth. Compressing the energy from its internal core lets it fire off an attack capable of blowing away a mountain. Its name seems to be a combination of the words ‘giga’, ‘Goliath’ (a colossal man described in different biblical verses who was considered unbeatable) and ‘lithos’ (a Greek word meaning “stone”).