Minecraft wiki entry for Superflat, associated text: Upon selecting "Superflat" in the World Type box, a new button appears underneath labeled "Customize". The customize menu starts with the "Classic Flat" preset of one layer of grass, two dirt layers, and then bedrock underneath. There are two buttons available to customize Superflat worlds, which include the "Remove Layer" button, used for removing unwanted types of layers, and the "Presets" button, used for selecting any of nine currently available presets.