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