Editing Ordovician (section)

==Subdivisions{{anchor|Subdivisions}}==
{{anchor|Tremadocian}}
In 2008, the [[International Classification for Standards|ICS]] erected a formal international system of subdivisions for the Ordovician Period and System.<ref>Details on the Dapingian are available at {{Cite journal| first1 = X.| first2 = S.| first3 = X.| first4 = Z.| first5 = C.| title = Dapingian Stage: standard name for the lowermost global stage of the Middle Ordovician Series| journal = [[Lethaia]]| volume = 42| issue = 3| pages = 377–380| last1 = Wang| year = 2009| doi = 10.1111/j.1502-3931.2009.00169.x| last2 = Stouge| last3 = Chen| last4 = Li| last5 = Wang}}</ref> Pre-existing Baltoscandic, British, Siberian, North American, Australian, Chinese, Mediterranean and North-[[Gondwana]]n regional stratigraphic schemes are also used locally.<ref>{{cite web |title=The Ordovician Period |url=https://ordovician.stratigraphy.org/period |website=Subcommission on Ordovician Stratigraphy |publisher=International Commission on Stratigraphy |access-date=7 June 2021 |date=2020 |archive-date=11 May 2022 |archive-url=https://web.archive.org/web/20220511072916/https://ordovician.stratigraphy.org/period |url-status=live }}</ref>

=== Global/regional correlation ===
{| class="wikitable"
|+ Approximate correlation of Ordovician regional series and stages<ref>{{Citation |last1=Goldman |first1=D. |title=The Ordovician Period |date=2020 |url=https://linkinghub.elsevier.com/retrieve/pii/B9780128243602000206 |work=Geologic Time Scale 2020 |pages=631–694 |access-date=2023-06-08 |publisher=Elsevier |language=en |doi=10.1016/b978-0-12-824360-2.00020-6 |isbn=978-0-12-824360-2 |last2=Sadler |first2=P.M. |last3=Leslie |first3=S.A. |last4=Melchin |first4=M.J. |last5=Agterberg |first5=F.P. |last6=Gradstein |first6=F.M. |archive-date=2023-01-06 |archive-url=https://web.archive.org/web/20230106135352/https://linkinghub.elsevier.com/retrieve/pii/B9780128243602000206 |url-status=live }}</ref>
|-
! [[Series (stratigraphy)|ICS series]] !! [[Stage (stratigraphy)|ICS stage]] !! British series!! British stage !! North American series !! North American stage !! Australian stage !! Chinese stage 
|-
| rowspan="10" |[[Upper Ordovician]] || [[Hirnantian]] || rowspan="4"| [[Ashgill series|Ashgill]]|| [[Hirnantian]] || rowspan="5" | Cincinnatian|| Gamachian|| rowspan="3" | Bolindian|| [[Hirnantian]]
|-
| rowspan="5"|[[Katian]] || Rawtheyan|| rowspan="2" | Richmondian|| rowspan="2" | Chientangkiangian
|-
| Cautleyan
|-
| Pusgillian|| Maysvillian
| rowspan="3" |Eastonian
| rowspan="7" |Neichianshanian
|-
| rowspan="6" |[[Caradoc series|Caradoc]] || Streffordian|| Edenian
|-
| Cheneyan
| rowspan="4" |Mohawkian
| rowspan="2" |Chatfieldian
|-
| rowspan="4" |[[Sandbian]] || rowspan="2" | Burrellian|| rowspan="4" |Gisbornian
|-
| rowspan="2" |Turinian
|-
| rowspan="2" | Aurelucian
|-
| rowspan="6" |[[Whiterockian]]
| rowspan="5" |
|-
| rowspan="5" |[[Middle Ordovician]]|| rowspan="3" |[[Darriwilian]]|| rowspan="2" |Llanvirn|| Llandeilo|| rowspan="3" | [[Darriwilian]]
| rowspan="3" |[[Darriwilian]]
|-
| Abereiddian
|-
| rowspan="7" |[[Arenig]]|| rowspan="2" | Fennian
|-
| rowspan="2" |[[Dapingian]]
|Yapeenian
| rowspan="2" |[[Dapingian]]
|-
| rowspan="3" |Whitlandian
|Rangerian
|Castlemainian
|-
| rowspan="9" |[[Lower Ordovician]]
| rowspan="4" |[[Floian]]
| rowspan="9" |Ibexian
| rowspan="3" |Blackhillsian||Chewtonian
| rowspan="4" |Yiyangian
|-
| rowspan="2" |Bendigonian
|-
| rowspan="2" | Moridunian
|-
| rowspan="2" |Tulean
| rowspan="5" |Lancefieldian
|-
| rowspan="5" | [[Tremadocian]]|| rowspan="5" |[[Tremadocian|Tremadoc]] || rowspan="2" | Migneintian|| rowspan="5" | Xinchangian
|-
| rowspan="2" |Stairsian
|-
| rowspan="3" |Cressagian
|-
| rowspan="2" | Skullrockian
|-
|Warendan
|}

=== British stages and ages ===
The Ordovician Period in Britain was traditionally broken into Early (Tremadocian and [[Arenig]]), Middle ([[Llanvirn Series|Llanvirn]] (subdivided into Abereiddian and Llandeilian) and [[Llandeilo Group|Llandeilo]]) and Late ([[Caradoc Series|Caradoc]] and Ashgill) epochs. The corresponding rocks of the Ordovician System are referred to as coming from the Lower, Middle, or Upper part of the column.

The Tremadoc corresponds to the ICS's Tremadocian. The Arenig corresponds to the Floian, all of the Dapingian and the early Darriwilian. The Llanvirn corresponds to the late Darriwilian. The Caradoc covers the Sandbian and the first half of the Katian. The Ashgill represents the second half of the Katian, plus the [[Hirnantian]].

==== Ashgill ====
The Ashgill Epoch, the last epoch of the British Ordovician, is made of four ages: the Hirnantian Age, the Rawtheyan Age, the '''Cautleyan''' Age, and the Pusgillian Age. These ages make up the time period from c. 450 Ma to c. 443 Ma.

The Rawtheyan, the second last of the Ashgill ages, was from c. 449 Ma to c. 445 Ma. It is in the Katian Age of the ICS's [[Geologic Time Scale]].