This also works with stone tools which are found abundantly at different sites and across long periods of time.Stratigraphic dating is based on the principle of depositional superposition of layers of sediments called strata.Stratigraphy is a key concept to modern archaeological theory and practice.Modern excavation techniques are based on stratigraphic principles.
Relative dating is different from absolute dating in which specific dates are assigned to geologic events (we will discuss absolute dating techniques later).
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.
If archaeologists know how pottery styles, glazes, and techniques have changed over time they can date sites based on the ratio of different kinds of pottery.
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.