Geology gave the world the gift of time: not just the measly millennia counted by old civilizations, but millions of years and billions of years, more years than anyone could count. It made even the absurdly long sacred chronologies of the Hindus look reasonable. And as we explored all that time, we figured out how to organize it into structures of time, hierarchies of time periods with, eventually, actual dates assigned to them. That's what this week's "Who Wants to Be a Geo-Whiz?" quiz is about: geologic time. Now don't dawdle, you've only got a week.