Early Silurian Epoch
(Lower Silurian)
From 443.7 +/- 1.5 To 422.9 +/- 2.5 Ma
Start Defined By: Graptolites, lowest occurrences of Parakidograptus
acuminatus and Akidograptus ascensus.
End Defined By: Imprecise. Just below base of local acritarch Leptobrachion
longhopense range zone. May be near base of Neodiversograptus nilssoni
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 --
Australian Stage: Melbournian (428.2 - 416)
Chinese Stage: Guandian (425.5 - 422)
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)
-- 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 --
Epoch: Late Silurian (422.9 - 416)
Sub-Epoch: Ludlow (422.9 - 418.7)
ICS Stage: Gorstian (422.9 - 421.3)
-- Contains the Following Sub-Epochs --
Sub-Epoch: Llandovery (443.7 - 428.2)
Sub-Epoch: Wenlock (428.2 - 422.9)
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