Fronian Regional Stage
From 437.5 To 436 +/- 1.9 Ma
End Defined By: Brachiopods, just above extinction of Eocoelia intermedia
and below lowest succeeding species Eocoelia curtisi. Near base of
Monograptus turriculatus graptolite zone.
End Based On: Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
-- 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)
Sub-Epoch: Llandovery (443.7 - 428.2)
ICS Stage: Aeronian (439 - 436)
Australian Stage: Keiloran (443.7 - 433)
Chinese Stage: Shinulanian (438 - 433)
North American Stage: Niagaran (438 - 421.3)
Regional Stage: Alexandrian (443.7 - 436)
-- Preceeded By --
Regional Stage: Idwian (439 - 437.5)
-- Followed By --
ICS Stage: Telychian (436 - 428.2)
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