Editing Geologic time scale (section)

=== Formulation of a modern geologic time scale ===
The apparent, earliest formal division of the geologic record with respect to time was introduced during the era of Biblical models by [[Thomas Burnet (theologian)|Thomas Burnet]] who applied a two-fold terminology to mountains by identifying "''montes primarii''" for rock formed at the time of the 'Deluge', and younger "''monticulos secundarios"'' formed later from the debris of the "''primarii"''.<ref name="Burnet_1681">{{Cite book |last=Burnet |first=Thomas |title=Telluris Theoria Sacra: orbis nostri originen et mutationes generales, quasi am subiit aut olim subiturus est, complectens. Libri duo priores de Diluvio & Paradiso |publisher=G. Kettiby |year=1681 |location=London |language=la}}</ref><ref name="Fischer_20093"/> [[Anton Moro]] (1687–1784) also used primary and secondary divisions for rock units but his mechanism was volcanic.<ref name="Moro_1740">{{Cite book |last=Moro |first=Anton Lazzaro |url=https://books.google.com/books?id=03RBAAAAYAAJ |title=De'crostacei e degli altri marini corpi che si truovano su'monti |date=1740 |publisher=Appresso Stefano Monti |language=it}}</ref><ref name="Fischer_20093"/> In this early version of the [[Plutonism]] theory, the interior of Earth was seen as hot, and this drove the creation of primary igneous and metamorphic rocks and secondary rocks formed contorted and fossiliferous sediments. These primary and secondary divisions were expanded on by [[Giovanni Targioni Tozzetti]] (1712–1783) and [[Giovanni Arduino (geologist)|Giovanni Arduino]] (1713–1795) to include tertiary and quaternary divisions.<ref name="Fischer_20093"/> These divisions were used to describe both the time during which the rocks were laid down, and the collection of rocks themselves (i.e., it was correct to say Tertiary rocks, and Tertiary Period). Only the Quaternary division is retained in the modern geologic time scale, while the Tertiary division was in use until the early 21st century. The Neptunism and Plutonism theories would compete into the early [[19th century]] with a key driver for resolution of this debate being the work of [[James Hutton]] (1726–1797), in particular his ''[[Theory of the Earth]]'', first presented before the [[Royal Society of Edinburgh]] in 1785.<ref name="Hutton_1788">{{Cite journal |last=Hutton |first=James |date=1788 |title=X. Theory of the Earth; or an Investigation of the Laws observable in the Composition, Dissolution, and Restoration of Land upon the Globe . |url=https://www.cambridge.org/core/product/identifier/S0080456800029227/type/journal_article |journal=Transactions of the Royal Society of Edinburgh |language=en |volume=1 |issue=2 |pages=209–304 |doi=10.1017/S0080456800029227 |s2cid=251578886 |issn=0080-4568}}</ref><ref name="Hutton_1795v1">{{Cite book |last=Hutton |first=James |url=https://www.gutenberg.org/ebooks/12861 |title=Theory of the Earth |year=1795 |volume=1 |location=Edinburgh}}</ref><ref name="Hutton_1795v2">{{Cite book |last=Hutton |first=James |url=https://www.gutenberg.org/ebooks/14179 |title=Theory of the Earth |year=1795 |volume=2 |location=Edinburgh}}</ref> Hutton's theory would later become known as [[uniformitarianism]], popularised by [[John Playfair]]<ref name="Playfair_1802">{{Cite book |last=Playfair |first=John |url=http://archive.org/details/NHM104643 |title=Illustrations of the Huttonian theory of the earth |date=1802 |publisher=Neill & Co |others=Digitised by London Natural History Museum Library |location=Edinburgh}}</ref> (1748–1819) and later [[Charles Lyell]] (1797–1875) in his ''[[Principles of Geology]]''.<ref name="Lyell_1832v1">{{Cite book |last=Lyell |first=Sir Charles |url=https://books.google.com/books?id=mmIOAAAAQAAJ |title=Principles of Geology: Being an Attempt to Explain the Former Changes of the Earth's Surface, by Reference to Causes Now in Operation |date=1832 |publisher=John Murray |volume=1 |location=London |language=en}}</ref><ref name="Lyell_1832v2">{{Cite book |last=Lyell |first=Sir Charles |url=https://books.google.com/books?id=TlwPAAAAYAAJ |title=Principles of Geology: Being an Attempt to Explain the Former Changes of the Earth's Surface, by Reference to Causes Now in Operation |date=1832 |publisher=John Murray |volume=2 |location=London |language=en}}</ref><ref name="Lyell_1834v3">{{Cite book |last=Lyell |first=Sir Charles |url=https://books.google.com/books?id=UrIJAAAAIAAJ |title=Principles of Geology: Being an Inquiry how for the Former Changes of the Earth's Surface are Referrable to Causes Now in Operation |date=1834 |publisher=John Murray |volume=3 |location=London |language=en}}</ref> Their theories strongly contested the 6,000 year age of the Earth as suggested determined by [[James Ussher]] via Biblical chronology that was accepted at the time by western religion. Instead, using geological evidence, they contested Earth to be much older, cementing the concept of deep time.

During the early 19th century [[William Smith (geologist)|William Smith]], [[Georges Cuvier]], [[Jean Baptiste Julien d'Omalius d'Halloy|Jean d'Omalius d'Halloy]], and [[Alexandre Brongniart]] pioneered the systematic division of rocks by stratigraphy and fossil assemblages. These geologists began to use the local names given to rock units in a wider sense, correlating strata across national and continental boundaries based on their similarity to each other. Many of the names below erathem/era rank in use on the modern ICC/GTS were determined during the early to mid-19th century.