The scholar most associated with the rules of stratigraphy (or law of superposition) is probably the geologist Charles Lyell.The basis for stratigraphy seems quite intuitive today, but its applications were no less than earth-shattering to archaeological theory.It was now possible to assign a calendar date to archaeological sites in the American southwest for over 1000 years.
His research culminated in proving that tree ring width varies with annual rainfall.
Using local pine trees, Douglass built a 450 year record of the tree ring variability.
Clark Wissler, an anthropologist researching Native American groups in the Southwest, recognized the potential for such dating, and brought Douglass subfossil wood from puebloan ruins.
For example, JJA Worsaae used this law to prove the Three Age System.
For more information on stratigraphy and how it is used in archaeology, see the Stratigraphy glossary entry.