In most places the mantle of regolith and soil does not continue to accumulate indefinitely. Sooner or later this loose material is picked up by erosion, transported downhill, deposited and lithified (turned into solid rock), to form a new group of rocks, sedimentary rocks. 

Sedimentary rocks are those rocks which are formed at the earth's surface. The primary source of materials which make up sedimentary rocks is all the loose weathering products that have been moved at the surface. In order to distinguish between in-place weathering products and the materials moved by erosion, the latter are given a new name: sediments.