Geologic Time Scale

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Across
  1. 2. Era with more complex life forms and dinosaurs
  2. 6. When older rock is surrounded by younger rock
  3. 7. Second time chunk (Mesozoic)
  4. 8. When species die off
  5. 9. When younger rock cuts across older rock
  6. 12. Era when Pangaea formed,life developed
  7. 13. Fourth time chunk (Holocene)
Down
  1. 1. Earth's geological history
  2. 3. Era with large mammals and humans
  3. 4. A rock layer is older or younger than another rock layer
  4. 5. Largest time chunk
  5. 10. Dating rock by the decay of radioactive isotope
  6. 11. Third time chunk (Jurassic)
  7. 12. Eon that marks Earth's beginning