principle of original horizontality example

It is the first of Smith's laws, which were formally published in Strata Identified by Fossils (1816–1819). In the English-language literature, the law was popularized by William 'Strata' Smith, who used it to produce the first geologic map of Britain.

The law of superposition was first proposed in 1669 by the Danish scientist Nicolas Steno, and is present as one of his major theses in the groundbreaking seminal work Dissertationis prodromus (1669). These findings can inform the community on the fossil record covering the relevant strata, to determine which species coexisted temporally and which species existed successively in perhaps an evolutionarily or phylogenetically relevant way. To illustrate the practical applications of superposition in scientific inquiry, sedimentary rock that has not been deformed by more than 90° will exhibit the oldest layers on the bottom, thus enabling paleontologists and paleobotanists to identify the relative ages of any fossils found within the strata, with the remains of the most archaic lifeforms confined to the lowest. This is paramount to stratigraphic dating, which requires a set of assumptions, including that the law of superposition holds true and that an object cannot be older than the materials of which it is composed.

In its plainest form, it states that in undeformed stratigraphic sequences, the oldest strata will lie at the bottom of the sequence, while newer material stacks upon the surface to form new deposits over time. The law of superposition is an axiom that forms one of the bases of the sciences of geology, archaeology, and other fields pertaining to geological stratigraphy.

Principle of original horizontality example