Which layers within an archaeological site are generally considered the oldest?

The lowest layers

Archaeological sites are formed as a result of human activities such as producing, using, and discarding materials and structures. The continuous occupation of a place leads to the accumulation of occupational debris, forming a mound. When a site is temporarily or permanently abandoned, natural processes like wind and water erosion can alter the landscape. Layers of different colors, textures, and artifacts within these mounds indicate different periods of occupation. Typically, the most inferior layers are the most aged and the highest are the most recent."Sterile layers" refer to layers devoid of traces of human activity. Stratigraphy, the study of these layers, helps assign artifacts to specific cultural periods and establish the cultural sequence of a site.