Underground Biomes Mod 1.7.2/1.6.4/1.5.2

Description:

Overhauls the underground experience with Underground Biomes that define the rock types and ores present.
These biomes occur differently to the surface biomes making exploration underground more interesting.
Adds 57 new blocks using 12 block IDs and 1 new item (so far):

8 types of...
Underground Biomes Mod 1.7.2/1.6.4/1.5.2 - http://www.8minecraft.org/underground-biomes-mod/