Methods of dating ancient fossils
Hutton, a Scottish geologist, first proposed formally the fundamental principle used to classify rocks according to their relative ages.He concluded, after studying rocks at many outcrops, that each layer represented a specific interval of geologic time.For each dating or chronological method there is a link in the box at right to take you to that section of this page.
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.Trees from the same species, growing in the same area or environment will be exposed to the same conditions, and hence their growth rings will match at the point where their lifecycles overlap.Earth's oldest living inhabitant "Methuselah" at 4,767 years, has lived more than a millennium longer than any other tree.Keyed to the relative time scale are examples of index fossils, the forms of life which existed during limited periods of geologic time and thus are used as guides to the age of the rocks in which they are preserved.William "Strata" Smith, a civil engineer and surveyor, was well acquainted with areas in southern England where "limestone and shales are layered like slices of bread and butter." His hobby of collecting and cataloging fossil shells from these rocks led to the discovery that certain layers contained fossils unlike those in other layers.