With the death of Bukkit, I will no longer be supporting this plugin. If it still works for you, fantastic. If not, you are on your own. All the source will remain available on GitHub. Farewell, -DeltaHat
Subterranea is a modification of the Vanilla terrain generator that switches the above and below ground spaces so your world has 192 layers below sea level and 64 layers above. Great for Mole Man worlds.

worlds: [worldname]: generator: Subterranea[:options]
bukkit.yml example
worlds: world: generator: Subterranea:-giant-caves
Notes:
The Subterranea world generator supports a number of options. Options are passed into the generator using the [:options] string in the above examples. Always put a colon between the word Subterranea and the options string.
-underground-biomes: (true or false, default true) Enables or disables underground bionme creation
-silverfish: (true or false, default true) Enables or disables silverfish colony creation hidden in the stone.
-giant-caves: (default sxz=500,sy=175,cutoff=65,miny=40,maxy=160) Enables or disables the Giant Caves plugin. An optional configuration string can be passed into this option to configure the Giant Caves generator. See the Giant Caves documentation for a description of each setting and how it affects cave creation. You need to install Giant Caves for this to work!
-ore-multiplier: (default 3) Sets how many passes the ore populator should make over each chunk. A value of three keeps about the same or density as vanilla. A value above ten may significantly slow down chunk creation.
Subterranea is compatible with Giant Caves. To add Giant Caves to a Subterranea world, just add -giant-caves to the [:options] string.
To use Subterranea with Multiverse, use the following sequence of commands
mv create world_name NORMAL -g "Subterranea[:options]"
mv tp world_name
Notes:
Multiverse Example:
mv create DeepWorld NORMAL -g "Subterranea:-underground-biomes true -silverfish true -giant-caves sxz=500,sy=175,cutoff=65,miny=10, maxy=180"
Create a new Subterranea world called DeepWorld with underground biomes, silverfish, and gaint caves from layer 10 to layer 180
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