Further, he proposed that wherever uncontorted layers were exposed, the bottom layer was deposited first and was, therefore, the oldest layer exposed; each succeeding layer, up to the topmost one, was progressively younger.
The Major Divisions of Geologic Time are shown here, arranged in chronological order with the oldest division at the bottom, the youngest at the top. Specifically, stratigraphy refers to the application of the Law of Superposition to soil and geological strata containing archaeological materials in order to determine the relative ages of layers.
[ While this may be true, a shrub in Tasmania could be 40,000 years old.
See Oldest Living Organism.] The Sheffield Laboratory now has a continuous master sequence for England going back to about 5000BC. This article should be a "must read" for any person interested in factualy accurate information on dating methods.
Because fossils actually record the slow but progressive development of life, scientists use them to identify rocks of the same age throughout the world.Many of these links also appear where appropriate below.James Hutton and William Smith advanced the concept of geologic time and strengthened the belief in an ancient world.Cross-dating is a technique used to take advantage of consistencies in stratigraphy between parts of a site or different sites, and objects or strata with a known relative chronology.A specialized form of cross-dating, using animal and plant fossils, is known as biostratigraphy.