Related Clues:
- Long time division
- Geological time span
- Span longer than an era
- Exceedingly long time
- Long time span
- Long time, geologically
- It may be after lunch
- Long geological stretch
- A billion years, to Hubble
- Coon's age
- What evolution might be measured in
- Dog's age
- Eternity, seemingly
- Long period of time
- A month of Sundays