Across
- 1. describes all the events on Earth's history
- 3. age of dinosaurs, time of intense tectonic, climatic and evolutionary activity
- 7. newer rock layers will be on top of older ones
- 8. rate of decay of the isotope
- 9. assumption of age (law of superposition)
- 10. represent a specific period of time to help them find an age
Down
- 2. gives age in actual years
- 4. any feature that cuts across a sequence of rocks is younger than everything it cuts.
- 5. oldest layer
- 6. youngest layer