Principle of Faunal Succession

The observation that fossilized flora and fauna succeed each other vertically in sedimentary rock in a specific, reliable order that can be identified over wide horizontal distances, so strata can be identified and dated by the fossils they contain. Named for the English geologist William Smith, who documented it in the first decade of the 19th century concurrently with Cuvier and Brongniart in France, it joins the law of superposition in fixing the time sequence of sedimentary rocks, and its refined practice is biostratigraphy. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/