Across
- 5. the ages of an event
- 8. weather conditions
- 9. arrangement of rock layers
- 12. of the origin, history
- 14. or younger
- 15. of ice obtained from drilling
Down
- 1. break in the geologic record
- 2. age of an object
- 3. or a coprolite
- 4. in the past
- 6. rocks lie above older rocks
- 7. earth's long natural history
- 10. of an organism that lived long ago
- 11. break down into a stable isotope
- 13. time required for half of a sample