Editing Nicolas Steno (section)

=== Geology and stratigraphy ===
[[File:Steno De Solido Dissertationis Prodromus 1669.jpg|thumb|upright|''De solido intra solidum naturaliter contento dissertationis prodromus'' (1669)]]
{{Main|law of superposition|principle of original horizontality|principle of lateral continuity}}
Steensen, in his ''Dissertationis prodromus'' of 1669 is credited with four of the defining principles of the science of [[stratigraphy]]. His words were:
# the [[law of superposition]]: "At the time when a given stratum was being formed, there was beneath it another substance which prevented the further descent of the comminuted matter and so at the time when the lowest stratum was being formed either another solid substance was beneath it, or if some fluid existed there, then it was not only of a different character from the upper fluid, but also heavier than the solid sediment of the upper fluid."
# the [[principle of original horizontality]]: "At the time when one of the upper strata was being formed, the lower stratum had already gained the consistency of a solid."
# the [[principle of lateral continuity]]: "At the time when any given stratum was being formed it was either encompassed on its sides by another solid substance, or it covered the entire spherical surface of the earth. Hence it follows that in whatever place the bared sides of the strata are seen, either a continuation of the same strata must be sought, or another solid substance must be found which kept the matter of the strata from dispersion."
# the [[principle of cross-cutting relationships]]: "If a body or discontinuity cuts across a stratum, it must have formed after that stratum."<ref>{{cite book |last=Steno |first=Nicolas |url=https://archive.org/details/cu31924012131458 |title=Nicolas Steno's Dissertation Concerning a Solid Body Enclosed by Process of Nature within a Solid: An English Version with an Introduction and Explanatory Notes |date=1916 |publisher=New York, Macmillan; London, Macmillan |translator-last1=Winter |translator-first1=John}} Pages 229–230.</ref>
These principles were applied and extended in 1772 by [[Jean-Baptiste L. Romé de l'Isle]]. Steensen's ideas still form the basis of stratigraphy and were key in the development of [[James Hutton]]'s theory of [[James Hutton#Search for evidence|infinitely repeating cycles]] of seabed deposition, uplifting, erosion, and submersion.{{sfnp|Brookfield|2004|p=116}}