Llandovery Sub-Epoch
From 443.7 +/- 1.5 To 428.2 +/- 2.3 Ma
Start Defined By: Graptolites, lowest occurrences of Parakidograptus
acuminatus and Akidograptus ascensus.
End Defined By: Imprecise. Between the base of acritarch biozone 5 and
extinction of conodont Pterospathodus amorphognathoides. May be near base
of Cyrtograptus centrifugus graptolite zone.
Start Based On: Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
End Based On: Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
-- Overlaps With --
Chinese Stage: Xiushanian (429 - 425.5)
North American Stage: Niagaran (438 - 421.3)
-- A Substage of --
Eon: Phanerozoic (542 - -5.5012e-005)
Era: Paleozoic (542 - 251)
Period: Silurian (443.7 - 416)
Epoch: Early Silurian (443.7 - 422.9)
-- Preceeded By --
Period: Ordovician (488.3 - 443.7)
Epoch: Late Ordovician (460.9 - 443.7)
ICS Stage: Hirnantian (445.6 - 443.7)
Australian Stage: Bolindian (450 - 443.7)
General Stage: Ashgill (449 - 443.7)
North American Stage: Cincinnatian (451 - 443.7)
-- Followed By --
Sub-Epoch: Wenlock (428.2 - 422.9)
ICS Stage: Sheinwoodian (428.2 - 426.2)
Australian Stage: Melbournian (428.2 - 416)
-- Contains the Following Stages --
ICS Stage: Rhuddanian (443.7 - 439)
ICS Stage: Aeronian (439 - 436)
ICS Stage: Telychian (436 - 428.2)
Australian Stage: Keiloran (443.7 - 433)
Australian Stage: Eildonian (433 - 428.2)
Chinese Stage: Longmaxian (443.7 - 438)
Chinese Stage: Shinulanian (438 - 433)
Chinese Stage: Baishaean (433 - 429)
North American Stage: Medinan (443.7 - 438)
Regional Stage: Alexandrian (443.7 - 436)
Regional Stage: Idwian (439 - 437.5)
Regional Stage: Fronian (437.5 - 436)
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