Related Clues:

• Geologic time division
• Amazingly long time
• An eternity
• Longish span
• DMV wait time, seemingly
• Nonspecific duration
• Quite a stretch
• Extended time
• Vast expanse of time
• Boundless time
• Geologic time unit
• A very long period of time
• 365 billion days, in astronomy
• Several eras
• It's quite a stretch