Sedimentary Rocks
Sedimentary rocks are types of rocks that are made by the recycled material at the Earth's surface and in the bodies of water. Sedimentary rocks are taken away in layers as strata, making layers and layers on top of the surface. Sedimentary rocks are important sources of natural resources like coal, fossil fuels, drinking water or ores.
http://en.wikipedia.org/wiki/Sedimentary_rock