Answer:
Principle of superimposition states that in undisturbed rock layers, the oldest rocks are on the bottom and the youngest rocks are on the top. Phenomena of withering is behind this process. The rocks are withered due to the effect of water and air. The sediments or soil particles gets accumulated at another location. The layers of sediments gets compact with time and leads to the formation of rocks. The rocks being older are covered by layers of sediments with course of time. These sediments gets compact again forms new rocks. By this way the new young rocks are formed over the older rocks.