Across
- 3. One of the first hominin fossils found
- 5. Process where elements break down
- 6. Used for short radioactive dating
- 7. Information about an organism's life
- 9. Formed when rocks lay on top of each other to form layers
- 10. Age of reptiles
- 11. Hard-shelled animals that lived in shallow seas
- 12. Age of Fish
- 14. The rate of radioactive decay
- 15. Formed when hot, molten rock crystallizes and solidifies
- 16. A theory of the creation of the universe
- 17. Formulated the theory of continental drift
- 18. Formed when rocks are subjected to high heat and high pressure
- 21. End of cretaceous, 65 MYA
- 23. When 50% of the species die out in a relatively short period of time
- 24. Age of mammals
Down
- 1. Single-celled organisms began
- 2. Early fish didn't have them
- 3. States that rocks on top are younger than rocks on the bottom
- 4. Used for long radioactive dating
- 8. First small dinosaurs appeared
- 13. Where new rock meets up with much older rocks
- 19. Only found on asteroids
- 20. 260 million years ago
- 22. 225 million years ago