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                              Early Devonian Epoch
                        (Lower Devonian, Helderbergian)
 
                      From 416 +/- 2.8 To 397.5 +/- 2.7 Ma
 
  Start Defined By:  Graptolite, lowest occurrence of Monograptus uniformis.
  End Defined By:  Conodont, lowest occurrence of Polygnathus costatus 
     partitus; major faunal turnover.
 
  Start Based On:  Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
  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:               Devonian    (416 - 359.2)
  North American Stage: Ulsterian   (416 - 391.8)
 
 -- Preceeded By --
  Period:               Silurian      (443.7 - 416)
  Epoch:                Late Silurian (422.9 - 416)
  Sub-Epoch:            Pridoli       (418.7 - 416)
  Australian Stage:     Melbournian   (428.2 - 416)
  North American Stage: Cayugan       (421.3 - 416)
 
 -- Followed By --
  Epoch:         Middle Devonian (397.5 - 385.3)
  ICS Stage:     Eifelian        (397.5 - 391.8)
  Chinese Stage: Yingtangian     (397.5 - 391.4)
 
 -- Contains the Following Stages --
  ICS Stage:     Lochkovian     (416 - 411.2)
  ICS Stage:     Praghian       (411.2 - 407)
  ICS Stage:     Emsian         (407 - 397.5)
  Chinese Stage: Yujianian      (410 - 407)
  Chinese Stage: Lianhuashanian (416 - 413)
  Chinese Stage: Nagaolingian   (413 - 410)
 

This page was automatically generated from the GeoWhen database (version 1.1.0).  Please read the introduction regarding the accuracy and reliability of this information.  Comments, corrections, and additions can be sent to geowhen@robertrohde.com.  References to published academic literature are preferred.

Introduction

Geologic Timeline
(No Stages)

Geologic Timeline
(With Stages)

A-Z Stage List

Regional Information

Download Files


2003-2005 GeoWhen Database
Prepared By Robert A. Rohde


This page was last updated on Tuesday, January 18, 2005.