'(<a href="http://www.j-archive.com/media/2006-06-12_DJ_20.jpg" target="_blank">Cheryl of the Clue Crew shows a ribboned timeline on the monitor.</a>)  Named for the tiny time period that followed it, this interval covers 80% of geological time'
Precambrian
KNOW YOUR EARTH: Named for the tiny time period that followed it, this interval covers 80% of geological time
Named for the tiny time period that followed it, this interval covers 80% of geological time
Named for the tiny time period that followed it, this interval covers 80% of geological time
KNOW YOUR EARTH
Precambrian
KNOW YOUR EARTH