Unravel the Mystery of Geological Span – Can You Solve the Crossword Clue?

1. A long period of time in geological history.
2. A sub-division of a geological eon.
3. Characterized by distinct climate and geology.
4. The Phanerozoic includes three of these.
5. The largest division of geological time.
6. Ends with a mass extinction event.
7. A period of time in which major geological and biological changes occur.