Clue: Billion-year time period
We have 1 possible answer for the clue Billion-year time period which appears 2 times in our database.
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Related Clues:
- Long time period
- Long interval
- 1,000,000,000 years
- One billion years, in geologic time
- Waiting period, it sometimes seems
- Division of geological time
- Long geological period
- An age
- It keeps going and going ...
- Many many years
- A million millennia
- Untold millennia
- The Phanerozoic, e.g.
- See 41 Down
- Era after era