When archaeologist dig the ground why do they usually find older remains at lower level?

Archaeologists typically find older remains at lower levels due to the principle of stratigraphy, which states that in undisturbed layers of soil, the oldest materials are found at the bottom and the youngest at the top. Over time, sedimentation processes, such as erosion and deposition, cause new layers of soil to accumulate over older layers. This natural layering reflects the chronological sequence of human activity and environmental changes, allowing archaeologists to date and understand the context of the artifacts and remains they uncover.