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American Geological Institute (AGI), Alexandria, VA: Earth Science World. Images from the Earth Science World Image Bank, geoscience books, information on careers in the geosciences, and more. Go to: Interactive Geological Time Scale.

BBC News: Geological time gets a new period. The Ediacaran Period covers some 50 million years of ancient time on our planet from 600 million years ago to about 542 million years ago.

BBC Earth timeline.
This expired link is now available through the Internet Archive´s Wayback Machine.

Museum of Paleontology (UCMP), University of California at Berkeley: Web Lift for Geological Time. See also: The Geologic Time Scale in Historical Perspective.

Simon Biggs: Fossil Collections of the World. Check the rubric Geology Time Scale. Not updated for a long time.

Goran Bogicevic, Department of Regional Geology and Palaeontology, Faculty of Mininig and Geology at Belgrade, Yugoslavia: Boggy´s Geolinks. Scroll down to: "Stratigraphy", e.g. Triassic.

Jamie Boyer, The New York Botanical Garden:
The Paleoplant Website. An educational resource for students and teachers studying Earth's history, fossils, and evolution.
! Go to: Geologic Time.

School of Earth Sciences, University of Bristol:
Your Planet Earth.
A library of talks on earth sciences and evolutionary topics that may be of interest to earth sciences and education professionals as a basis for engagement and outreach shows in schools. Go to:
The History of Life. Powerpoint Presentation.
Geological Time. Powerpoint Presentations.
Websites outdated. Links lead to versions archived by the Internet Archive´s Wayback Machine.

The British Geological Survey (BGS):
BGS Education, The BGS Geological Timechart. Colourful reference material, for use in schools, colleges and the home, setting out the geological timescale and geochronological terms, used at the British Geological Survey.

Laurie Cantwell, (Montana State University), The Science Education Resource Center (SERC), Carleton College: Teaching Geoscience with Visualizations: Using Images, Animations, and Models Effectively, Geologic Time. This website highlights animations, images, interactive graphics and videos used to teach the concept of geologic time in an introductory geology course. Visualizations cover the specific topics of earth history, relative age dating and life through geologic time.
Website outdated. The link is to a version archived by the Internet Archive´s Wayback Machine.

ES Designs: Geologic Time Scale. This geologic time scale provides a directory of links to web pages for each time interval.

Deutsche Stratigraphische Kommission (German Stratigraphic Commission), im Deutschen Nationalkomitee (DNK), für die International Union of Geological Sciences (IUGS). In German.

J. Dodick and N. Orion (2006): Building an understanding of geological time: A cognitive synthesis of the "macro" and "micro" scales of time. PDF file, in C. Manduca and D. Mogk, eds., Earth and Mind: How Geologists Think and Learn about the Earth: Geological Society of America, p. 77-94.

Brandon Dugan and Carrie Masiello, Rice University, Houston, TX:
Evolution of the Earth. Lecture notes, Powerpoint presentations.
! You may navigate from here, e.g.:
Lecture 2, Dynamic and Evolving Earth.
Lecture 3, Dynamic and Evolving Earth. Many paleogeographical maps!
Lecture 8, Understanding Geologic Time.
Lecture 25, Late Paleozoic Earth History.

! Geological Society of America:
Geologic Time Scale.

Geology.com: Geologic Time Scale. A printable time line for the geological sciences.

! F.M. Gradstein and J.G. Ogg (2020): The chronostratigraphic scale. In PDF, In: The Geologic Time Scale 2020, Elsevier. See also here (Google books).

! F.M. Gradstein et al. (2012): On The Geologic Time Scale. In PDF, Newsletters on Stratigraphy, 45: 171–188. See also here.

! F.M. Gradstein et al. (2012): The Geologic Timescale 2012. Poster, in PDF. See also here..
Worth checking out: Table of contents volume 1 and 2!

F.M. Gradstein et al.(2012): The Geologic Time Scale 2012. Google books, see also here (Table of contents, Elsevier).

! F.M. Gradstein and J.G. Ogg (2009): The geological time scale. PDF file, In: S.B. Hedges and S. Kumar (eds.): The Timetree of Life (see here).

! Daniel Hauptvogel, Virginia Sisson et al. (2023), Department of Earth and Atmospheric Sciences at the University of Houston:
The Story of Earth: An Observational Guide 2e . Second edition (Pressbooks), Open access. You can download a printable PDF version.
Navigate from the content menue page. Note especially:
! Chapter 1: Geologic Time.

! S.B. Hedges and S. Kumar (2009): Discovering the Timetree of Life. PDF file, In: S.B. Hedges and S. Kumar (eds.): The Timetree of Life.
! See here.
These expired links are now available through the Internet Archive´s Wayback Machine.

! S.B. Hedges (2009): Life. PDF file, In: S.B. Hedges and S. Kumar (eds.): The Timetree of Life.
! See here.
These expired links are now available through the Internet Archive´s Wayback Machine.

! hhmi BioInteractive (The Howard Hughes Medical Institute (HHMI)).
BioInteractive is a leading provider of free classroom resources and professional development for high school and undergraduate biology educators.
! EarthViewer. This interactive module allows to explore the science of Earth's deep history, from its formation 4.5 billion years ago to modern times. Excellent!

! Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ.
The Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences is Germany’s national research center for the solid Earth Sciences. Go to:
! Stratigraphic Table of Germany Compact 2022 (STGC 2022). In PDF; currently provided by Bibliothek Wissenschaftspark Albert Einstein.

C. Huang et al. (2020): Cyclostratigraphy and astrochronology: Case studies from China. Open access, Palaeogeography, Palaeoclimatology, Palaeoecology, 560.

! International Commission on Stratigraphy (ICS).
The ICS is the largest and oldest constituent scientific body in the International Union of Geological Sciences (IUGS). Its primary objective is to define precisely global units (systems, series and stages) of the International Chronostratigraphic Chart. Go to:
! Chart.
Downloadable latest chart versions in PDF or JPG.

The Jackson School of Geosciences at The University of Texas at Austin.
Courses & Catalogs. Go to: Time Scales
Lecture notes, Powerpoint presentation.

! C. King (2022):
Exploring Geoscience across the globe. In PDF (42 MB), Excellent!
Provided by The International Geoscience Education Organisation (IGEO). Chapters that may be of interest:
Chapter 3.2 (starting on pdf-page 30): e.g. Relative dating, Absolute dating.
Chapter 4.1.2.2 (starting on pdf-page 56): e.g. Sedimentary processes.
Chapter 4.3 (starting on pdf-page 115): e.g. Atmospheric change.
Chapter 4.4.1 (starting on pdf-page 122): e.g. Evolution.

S.E. Lewis et al. (2005): Once in a Million Years: Teaching Geologic Time. Helping students understand the magnitude of geologic time. In PDF, American Inst. of Biological Sciences, Washington, DC.
See also here.

LithStrat (supported by the Österreichische Akademie der Wissenschaften). A lithostratigraphical database. Provided by the Internet Archive´s Wayback Machine. Go to: Richtlinien zur stratigraphischen Nomenklatur. A guide about stratigraphical nomenclature (in German). From Steininger & Piller (1999), Courier Forschungsinstitut Senckenberg, 209.

Andrew MacRae: Radiometric Dating and the Geological Time Scale. Circular Reasoning or Reliable Tools? This TalkOrigins site (a Usenet newsgroup devoted to the discussion and debate of biological and physical origins) discusses the way radiometric dating and stratigraphic principles are used to establish the conventional geological time scale.

! G.V. Middleton et al. (eds., 2003): Encyclopedia of Sediments and Sedimentary Rocks. In PDF (2759 PDF pages), Kluwer Academic Publishers, Dordrecht, The Netherlands.
See also here. Part of the book series: Encyclopedia of Earth Sciences Series (EESS).
! You can quickly navigate from the Table of contents (251 entries).

! J.G. Ogg et al. (2020): The triassic period. In PDF, Geologic Time Scale 2020, Volume 2: 903-953. See also here.
! Note the generalized synthesis of selected Triassic stratigraphic scales in Figs. 25.5-25.7!

Peabody Museum of Natural History, Yale University:
Geologic Time Scale. Powerpoint presentation.

Sue Rigby, Geology, Geophysics, Environmental Geoscience, Grant Institute, University of Edinburgh: COURSE MATERIALS. Go to: GEP COURSE MATERIALS, The Geological Time Scale. PDF file.

! Robert A. Rohde, International Commission on Stratigraphy (ICS):
GeoWhen Database. GeoWhen Database is an attempt to sort out the mess that man has made of the geologic timescale. This project aims to reconcile the international stratigraphic standards with many of the regional and archaic naming schemes that appear in the literature. The central stratigraphic classification and dates are based on the 2004 time scale endorsed by the International Commission on Stratigraphy (ICS) and documented in Gradstein, Ogg, Smith, et al., A Geologic Time Scale 2004.

S. Shen et al. (2022): How to Build a High-Resolution Digital Geological Timeline?. In PDF, Journal of Earth Science, 33: 1629-1632.

South Carolina Geological Survey.
Education and Outreach. Downloadable Earth Science Education presentations, posters, and handouts. Go to:
Geologic Time and Earth’s Biological History. Powerpoint presentation. Also available in PDF.

STRATA (provided by Society for Sedimentary Geology, SEPM).
SEPM’s stratigraphy open access web site is dedicated to helping people understand sedimentary geology, from the basics to the detailed. Superbly done! See especially:
Sediments & Rocks.
Depositional Analogues.
Paleontology.

! TimeScale Creator (by Geologic TimeScale Foundation). TimeScale Creator, a free JAVA package, enables you to explore and create charts of any portion of the geologic time scale from an extensive suite of global and regional events in Earth History. See also:
A. Lugowski (Computer Science Dept., Univ. Calif. Santa Barbara) and J. Ogg (Dept. Earth and Atmos. Sci., Purdue University): TimeScale Creator. Provided by the Internet Archive´s Wayback Machine.

U.S. Geological Survey:
! Geologic Time. Go to:
Major Divisions of Geologic Time, Etymology of geological time units.

! U.S. Geological Survey, Reston, VA: Geolex. Geolex is a search tool for lithologic and geochronologic unit names.

U.S. Geological Survey (USGS), Reston, VA: The Learning Web. A site dedicated to K-12 education and life-long learning. Go to: Mud Fossils, Major Divisions of Geological Time.
Now recovered from the Internet Archive´s Wayback Machine.

US Geological Survey and the National Park Service: USGS Geology in the Parks, What is Geologic Time?

USGS/Cascades Volcano Observatory, Vancouver, Washington: The Geologic Time Scale.

G.B. Vai (2007): A history of chronostratigraphy. PDF file, in: McGowran, B. (ed.): Beyond the GSSP: New Developments in Chronostratigraphy: Stratigraphy, 4: 173–185.

! Wikibooks, the open-content textbooks collection: High School Earth Science.
Contributed by John Benner et al. Worth checking out:
Evidence About Earth´s Past.
Earth´s History.

Wikipedia, the free encyclopedia:
Radiometric dating.
Geochronology.
List of geochronologic names.
Age of the Earth.
! Geologic time scale.
Global Boundary Stratotype Section and Point.

Wikipedia, the free encyclopedia:
! Timeline of the evolutionary history of life.

Wikipedia, the free encyclopedia:
! Global Boundary Stratotype Section and Point.
Category:Geochronologically significant locations.
Category:Geologic time scales of Earth.
Global Stratotype Section and Point (in German).

J. Witteveen (2024): Golden spikes, scientific types, and the ma (r) king of deep time. Free access, Studies in History and Philosophy of Science, 106: 70-85.