woar

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Across
  1. 5. subdivision of an era
  2. 8. states that younger rock is found above older rock when comparing sedimentary rock layers
  3. 10. refers to the information provided by all the discovered fossils throughout earths history
  4. 13. subdivision of a eon
  5. 14. a fossilized piece of evidence of an organisms activity
  6. 15. occurs when a species dies out and no longer lives on the planet
  7. 16. very large division of geologic time usually referred to as the longest division of time
  8. 17. a common fossil found in ment areas from a specific time. used to help identify the age of other formations
Down
  1. 1. the system of time measurement involving the formation and changes to earth
  2. 2. method of determining the age based on measuring radioactive elements
  3. 3. fossil that froms when organic material is pressed between layers of rock
  4. 4. fossil that forms when minerals solidify into rock around the shape of the original organisms. leaving a cavity behind
  5. 6. fossil that forms when organic material is trapped in ice, rock, amber or tar
  6. 7. the branch of science involving the physical composition and history of earth
  7. 9. age determination of the age of a rock based on the surrounding evidence
  8. 11. fossil that forms when a mold is filled with sediment and hardens into the shape of that organism
  9. 12. remains or impression of an organism preserved in petrified rock
  10. 13. subdivision of a period shortest division of geologic time