Chronometric dating relative dating
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.
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.
Unfortunately, the wood from the pueblos did not fit into Douglass's record, and over the next 12 years, they searched in vain for a connecting ring pattern, building a second prehistoric sequence of 585 years.
In 1929, they found a charred log near Show Low, Arizona, that connected the two patterns.
For more information on stratigraphy and how it is used in archaeology, see the Stratigraphy glossary entry.
Seriation, on the other hand, was a stroke of genius.
First used, and likely invented by archaeologist Sir William Flinders-Petrie in 1899, seriation (or sequence dating) is based on the idea that artifacts change over time.
Not only that, it varies regionally, such that all trees within a specific species and region will show the same relative growth during wet years and dry years.
Each tree then, contains a record of rainfall for the length of its life, expressed in density, trace element content, stable isotope composition, and intra-annual growth ring width.