The Extract.
The Extract is the floating land that was added in minecraft by firefox4, as of 1.1 it is now removed but will come back in the next update.
Origin
On the ChunkLands page there is a picture of a floating island that became The Extract.
Antlion Hill
There is also a new type of land yet to be added. It is a chunk risen, similar to the ChunkLands, but the stone and coal ore is replaced with cobblestone, and moss cobblestone, dirt is clay, and grass is sand, this area is probably going to be called Antlion Hill but however it is now unlikely to be added.
Gallary
The Extract viewed up close.
The Antlion Hill.