Further, he proposed that wherever uncontorted layers were exposed, the bottom layer was deposited first and was, therefore, the oldest layer exposed; each succeeding layer, up to the topmost one, was progressively younger.The Major Divisions of Geologic Time are shown here, arranged in chronological order with the oldest division at the bottom, the youngest at the top. Specifically, stratigraphy refers to the application of the Law of Superposition to soil and geological strata containing archaeological materials in order to determine the relative ages of layers.The Carbon14 technique has been and continues to be applied and used in many, many different fields including hydrology, atmospheric science, oceanography, geology, palaeoclimatology, archaeology and biomedicine. Isochron methods avoid the problems which can potentially result during radiometric testing.Be sure to see An Animated Isochron Diagram, or, Watching a Rock Age on an Isochron Diagram. Radiometric Dating from The Evolution Evidence Page.
He concluded, after studying rocks at many outcrops, that each layer represented a specific interval of geologic time.See more information about "Strata" Smith and his original geologic map of England.