Related Clues:

• Ages on end
• Major stretches
• Time beyond measure
• Indefinitely long time
• Huge time stretch
• L-o-n-g time
• Dark __
• Geology period
• Census stats
• Lengthy time unit
• A long long time
• It's going to be quite a while
• Mellows, like wine
• Reacts to time
• Mellows, in a way