Layers

Surface
The surface includes the Forest, Dungeon, Desert, Corruption, Meteorite, and Ocean biomes. This layer has a dirt only backdrop.

Usually spans from +0ft upwards.

Contains:
 * Wood
 * Soil - Dirt, Mud, Sand, Clay, Stone
 * Ore - Iron, Copper, Silver (rare), Gold (rare)
 * Gems - (Very Rare)

Underground
The underground contains the Underground, Dungeon, Underground Jungle, and Corruption biomes.

Usually this layer begins at the -0ft mark and expands downward to around -850ft.

Contains:
 * Soil - Dirt, Mud, Sand, Clay, Stone
 * Ore - Iron, Copper, Silver (uncommon), Gold (uncommon)
 * Gems - (Rare)
 * Glowing Mushrooms - (Rare)

Caverns
The cavern layer contains the Cavern Layer, Dungeon, and Underground Jungle biomes.

Usually this layer begins at the -850ft mark and expands downward to around -3000ft.