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.The most common relative dating method is stratigraphy.Other methods include fluorine dating, nitrogen dating, association with bones of extinct fauna, association with certain pollen profiles, association with geological features such as beaches, terraces and river meanders, and the establishment of cultural seriations.Cultural seriations are based on typologies, in which artifacts that are numerous across a wide variety of sites and over time, like pottery or stone tools.
Relative dating is different from absolute dating in which specific dates are assigned to geologic events (we will discuss absolute dating techniques later).
This principle presumes that the oldest layer of a stratigraphic sequence will be on the bottom and the most recent, or youngest, will be on the top.
The earliest-known hominids in East Africa are often found in very specific stratigraphic contexts that have implications for their relative dating.
The concept derives from the geological use of the idea that sedimentation takes place according to uniform principles.
When archaeological finds are below the surface of the ground (as is most commonly the case), the identification of the context of each find is vital in enabling the archaeologist to draw conclusions about the site and about the nature and date of its occupation.
This idea is known as Plutonism, in reference to the God of the deep underworld.