PBS
Pbs Learning Media: The Wall of Time
This illustrated timeline from the Lunar and Planetary Institute provides a journey through four-and-a-half billion years of time from the birth of our solar system to its current existence today.
University of California
Ucmp: Web Geological Time Machine
The Museum of Paleontology at Berkeley offers an online geological time machine which allows you to catch a glimpse of ancient eras in earth's history. Click into an "Era" to learn about its stratigraphy, life forms, localities, and...
Other
Western Oregon University: Earth System Science: Geologic Time [Pdf]
An 81-page slideshow that looks at the principles of geology with respect to relative dating, at different concepts describing geological processes, at absolute age and radiometric dating, at the eons and eras in the geologic time scale,...
Estrella Mountain Community College
Online Biology Book: Paleobiology: The Late Paleozoic
College-level biology book covers the Late Paleozoic geologic time period in Earth's history. See photographs of fossil evidence from that era in addition to diagrams to help with understanding.
Sophia Learning
Sophia: Paleozoic Era
A brief overview illustrating the Paleozoic era in Earth's geologic history.