Quarry is a mod that adds, well, a quarry biome. The biome consists of clay being the top layer, and 2-3 layers of coal. Animals can spawn in the quarry, but only around where the water has ran down to form puddles.
The biome is quite large and rocky, but is certainly a good place to be if you're struggling to find some clay or coal.
To install this mod, you will need Forge, once Forge is installed, drag the mod's .zip file to /mods/ folder inside your .Minecraft directory.
