Related Clues:

• A lo-o-ong time
• Two or more eras
• Very long stretch
• Geologist's measure
• Time on end
• Many, many moons
• Unit of Time
• Billion years, to a geologist
• Millennia upon millennia
• It seems like forever
• Many centuries
• Millions of years
• Big time?
• Countless years
• Years and years and years