Across
- 4. Era when early life emerged
- 7. Measuring rates of decay of isotopes to determine the exact age of a rock or fossil
- 9. Era when rocks and plates formed
- 10. Time it takes for half of an isotope to decay
Down
- 1. Leftover traces of ancient organisms
- 2. Older fossils will be below younger fossils
- 3. Current Era
- 5. Era with chaotic conditions
- 6. newer rock layers are on top of older layers if not disturbed
- 8. Era of Dinosaurs