Geologic Time (Popularity: )
http://pubs.usgs.gov/gip/geotime/ USGS on-line publication about the relative and radiometric geologic time scales, age of the earth, index fossils, and related topics.
Berkeley Geochronology Center (Popularity: )
http://www.bgc.org/ Non-profit scientific research institution dedicated to establishing the history of the Earth, its various inhabitants, and its interactions with the ...