Sedimentary rocks are one of the three different classifications of rocks. Unlike the other two types of rocks that are formed through pressure and heat, sedimentary rocks are formed by the depositing of sediments on the surface of the Earth or under a body of water. The sediment particles are formed through the erosion of minerals and organic materials and the resulting sediments are carried by water, wind, and glaciers to a point of depositing. Also, dissolved minerals in water can precipitate as sediment to collect on the bottom of a body of water. Over time these sediments fuse together and form layered rocks on the surface of the Earth. The study of the different layers of sedimentary rocks can give important information about the geological history of a particular area.