Related Clues:
- 365 billion days, geologically
- Big stretch?
- A million millennia (Var.)
- Long geological span
- Two or more eras, in geologic time
- Largest geologic time division
- Long time-
- Longest division of geologic time
- It takes forever
- '___ Flux'
- Unimaginably long time (Var.)
- Proterozoic, for one
- Vast time unit
- Largest division of geologic time
- One billion years (Var.)