vocab

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Across
  1. 2. younger rocks lie above older rocks
  2. 6. process, radioactive isotope
  3. 9. study of the original history
  4. 12. older or younger
  5. 14. weather conditions
Down
  1. 1. divide earth's long natural history
  2. 3. trace or remains
  3. 4. cylinder of ice
  4. 5. time required for half of a sample Radiometric-dating method determining the absolute age
  5. 7. geologic process
  6. 8. method of measuring
  7. 10. arrangement of rock layers
  8. 11. break in the geologic record
  9. 13. sedimentary rock by animal activity