Minecraft wiki entry for Old_Customized, associated text: The default scenery is not seen in the finished world, because each biome has specific properties. Plains are flat, hills have small to medium elevations, extreme mountains are high mountain ranges, oceans have deep valleys, savannas and mesas have low mountains with flat plateaus, etc. Each biome type has an individual biome depth (Biome Depth) and an individual biome factor (Biome Scale) in order to perform the biome specific deformations.