Across
- 2. any piece of rock that has become included in another rock
- 5. calendar of events in earths history
- 6. a fossil which is useful for dating
- 8. unstable atomic nucleus looses energy by radiation
- 9. determining an age on a specific time scale
- 10. a geologic feature must be younger than any rock across which it cuts
Down
- 1. a geographical age starting with the presence of humans
- 3. law of geochronology
- 4. a layer of material, naturally or artificially formed
- 7. determining the relative order of past events