Across
- 4. a younger piece of rock going through older ones
- 5. close to the time
- 8. the longest portion of geological time
- 10. rocks in layers with oldest at the bottom
Down
- 1. the amount of time it takes for half of the remaining isotope to decay to a daughter product
- 2. remain
- 3. a very long period of time
- 6. having to do with the earth
- 7. older pieces of rocks embedded in younger ones
- 9. precise time