As a quick review, soil development is first predicated on the formation of the parent material. Parent material accumulates via the weathering of igneous, sedimentary, and metamorphic rocks. Igneous rocks are ones from volcanic activity, sedimentary rocks are formed from glacial deposits, water or wind action, and metamorphic rocks are ones formed from the other two types after undergoing extreme pressures and heat deep within the earth. These three types of rocks would require separate tutorials of their own for complete understanding. However, for now, just realize that these three rock types are the basis for the development of soil.