Editing Silurian (section)

== History of study ==
{{Life timeline}}
The Silurian system was first identified by the Scottish geologist [[Roderick Murchison]], who was examining fossil-bearing sedimentary rock [[Stratum|strata]] in south [[Wales]] in the early 1830s. He named the sequences for a [[Celts|Celtic]] tribe of Wales, the [[Silures]], inspired by his friend [[Adam Sedgwick]], who had named the period of his study the [[Cambrian]], from a [[Latin]] name for Wales.<ref>See:
*  {{cite journal |last1=Murchison |first1=Roderick Impey |title=On the Silurian system of rocks |journal=Philosophical Magazine |date=1835 |volume=7 |pages=46–52 |url=https://babel.hathitrust.org/cgi/pt?id=umn.31951d01457537j&view=1up&seq=60 |series=3rd series |issue=37 |doi=10.1080/14786443508648654}}  From p. 48:  " … I venture to suggest, that as the great mass of rocks in question, trending from south-west to north-east, traverses the kingdom of our ancestors the Silures, the term "Silurian system" should be adopted … "
*  {{cite book |last1=Wilmarth |first1=Mary Grace |title=Bulletin 769: The Geologic Time Classification of the United States Geological Survey Compared With Other Classifications, accompanied by the original definitions of era, period and epoch terms |date=1925 |publisher=U.S. Government Printing Office |location=Washington, D.C., U.S. |page=80 |url=https://books.google.com/books?id=my7x_PBkpm4C&pg=PA80}}</ref> Whilst the British rocks now identified as belonging to the Silurian System and the lands now thought to have been inhabited in antiquity by the Silures show little correlation ([[wiktionary:cf|{{abbr|cf|compare}}]]. [[:File:Geologic map Wales & SW England EN.svg|Geologic map of Wales]], [[:File:Wales.pre-Roman.jpg|Map of pre-Roman tribes of Wales]]), Murchison conjectured that their territory included [[Caer Caradoc]] and [[Wenlock Edge]] exposures - and that if it did not there were plenty of Silurian rocks elsewhere 'to sanction the name proposed'.<ref>{{Cite journal |last=Murchison |first=Roderick |date=1835 |title=On the Silurian System of Rocks |url=https://www.biodiversitylibrary.org/item/20069#page/62/mode/thumb |journal=The London and Edinburgh Philosophical Magazine and Journal of Science |volume=Third Series, Vol. 7 |pages=46–52 |via=Biodiversity Heritage Library}}</ref> In 1835 the two men presented a joint paper, under the title ''On the Silurian and Cambrian Systems, Exhibiting the Order in which the Older Sedimentary Strata Succeed each other in England and Wales,'' which was the germ of the modern [[Geologic time scale|geological time scale]].<ref>{{cite journal |last1=Sedgwick |last2=Murchison |first2=R.I. |title=On the Silurian and Cambrian systems, exhibiting the order in which the older sedimentary strata succeed each other in England and Wales |journal=Report of the Fifth Meeting of the British Association for the Advancement of Science. § Notices and Abstracts of Miscellaneous Communications to the Sections. |date=1835 |volume=5 |pages=59–61 |url=https://www.biodiversitylibrary.org/item/252891#page/397/mode/1up}}</ref> As it was first identified, the "Silurian" series when traced farther afield quickly came to overlap Sedgwick's "Cambrian" sequence, however, provoking furious disagreements that ended the friendship.

The English geologist [[Charles Lapworth]] resolved the conflict by defining a new [[Ordovician]] system including the contested beds.<ref>{{cite journal |last1=Lapworth |first1=Charles |title=On the tripartite classification of the Lower Palaeozoic rocks |journal=Geological Magazine |date=1879 |volume=6 |pages=1–15 |url=https://books.google.com/books?id=JJpZAAAAYAAJ&pg=PA1 |series=2nd series |issue=1 |doi=10.1017/s0016756800156560|bibcode=1879GeoM....6....1L |s2cid=129165105 }} From pp. 13–14: "North Wales itself – at all events the whole of the great Bala district where Sedgwick first worked out the physical succession among the rocks of the intermediate or so-called ''Upper Cambrian'' or ''Lower Silurian'' system; and in all probability much of the Shelve and the Caradoc area, whence Murchison first published its distinctive fossils – lay within the territory of the Ordovices; … Here, then, have we the hint for the appropriate title for the central system of the Lower Palaeozoics. It should be called the Ordovician System, after this old British tribe."</ref> An alternative name for the Silurian was ''"Gotlandian"'' after the [[Geology of Gotland|strata of the Baltic island of Gotland]].<ref>The Gotlandian system was proposed in 1893 by the French geologist [[Albert Auguste Cochon de Lapparent]] (1839–1908): {{cite book|last1=Lapparent|first1=A. de|url=https://babel.hathitrust.org/cgi/pt?id=umn.31951d00130906i&view=1up&seq=180|title=Traité de Géologie|date=1893|publisher=F. Savy|edition=3rd|volume=2|location=Paris, France|page=748|language=fr}} From p. 748: ''"D'accord avec ces divisions, on distingue communément dans le silurien trois étages: l'étage inférieur ou ''cambrien'' (1); l'étage moyen ou ''ordovicien'' (2); l'étage supérieur ou ''gothlandien'' (3)."'' (In agreement with these divisions, one generally distinguishes, within the Silurian, three stages: the lower stage or ''Cambrian'' [1]; the middle stage or ''Ordovician'' [2]; the upper stage or ''Gotlandian'' [3].)</ref>

The French geologist [[Joachim Barrande]], building on Murchison's work, used the term ''Silurian'' in a more comprehensive sense than was justified by subsequent knowledge. He divided the Silurian rocks of [[Bohemia]] into eight stages.<ref>{{cite book |last1=Barrande |first1=Joachim |title=Systême silurien du centre de la Bohême |date=1852 |publisher=(Self-published) |location=Paris, France and Prague, (Czech Republic) |pages=ix–x |url=https://babel.hathitrust.org/cgi/pt?id=uc1.31210012884258&view=1up&seq=19 |language=fr}}</ref> His interpretation was questioned in 1854 by [[Edward Forbes]],<ref>{{cite journal |last1=Forbes |first1=Edward |title=Anniversary Address of the President |journal=Quarterly Journal of the Geological Society of London |date=1854 |volume=10 |pages=xxii–lxxxi |url=https://babel.hathitrust.org/cgi/pt?id=hvd.32044102915394&view=1up&seq=50}} See p. xxxiv.</ref> and the later stages of Barrande; F, G and H have since been shown to be Devonian. Despite these modifications in the original groupings of the strata, it is recognized that Barrande established Bohemia as a classic ground for the study of the earliest Silurian fossils.