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Geology 105: History of Life
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Geologic Time Scale

Geologic Time Scale

This Geologic Time Scale provides a directory of links to web pages for each time interval.

The links focus on:

  • general information on the time period
  • paleogeography for the period
  • representative fossils of the period

Help Maintain This Site
Eon Era Period Age at Base*
Phanerozoic Cenozoic Quaternary 1.6 Ma
Tertiary 65 Ma
Mesozoic Cretaceous 140 Ma
Jurassic 205 Ma
Triassic 250 Ma
Paleozoic Permian 290 Ma
Carboniferous 355 Ma
Devonian 410 Ma
Silurian 438 Ma
Ordovician 510 Ma
Cambrian 540 Ma
Precambrian Proterozoic Vendian 680 Ma

2500 Ma
Archean 3960 Ma
Hadean 4550 Ma
* Ma = million years ago

Links to the other Geologic Time Scales on the web:

Many of the links on the directory pages were found by members of the Spring 1998 "History of Life" course at San Francisco State University.

Updated: 4/15/99
Site Design by: ES Designs
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