Across
- 2. Superpositon is layers are stacks on eachother
- 4. a eon is a very long time period
- 5. Relative age is the estimated age of something
- 8. A long period of history
- 10. The mesozoic eon is the age of the first land species.
Down
- 1. Absolute age is the exact age of something
- 3. Pangaea is a supercontinent
- 6. time periods are short pieces of history.
- 7. The paleozoic eon was the first of the marine species
- 9. a person who studies the structure of Earth's history