Soul Sand Valley

The Soul Sand Valley is a biome located in the Nether. It consists of a large cavern with fossils and many different blocks.

Description
A Soul Sand Valley is a large, cavern or grotto-like biome that is extensive and cuts through the Nether's usual terrain. Notable features of the biome are exposed fossils in various shapes and sizes, large amounts of lava, blue fog, large spires made of basalt and soul fire. The biome itself consists of soul sand, basalt and soul soil.

The only mobs that can spawn in a soul sand valley are skeletons, ghasts and endermen.