Earth history

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Across
  1. 2. a solid inorganic substance of natural occurrence
  2. 3. long and distinct period of history with a particular feature of characteristic
  3. 4. how long the earth has exsisted
  4. 7. matter that settles to the bottom of a liquid
  5. 12. the idea that rock layers get older the closer they are to the bottom
  6. 13. lighter than most rocks its size(pores)
  7. 14. minerals resistance to being scratched
  8. 15. represents ancient sea water
Down
  1. 1. inside rocks (granite)
  2. 5. walk on planet earth
  3. 6. rocks form when existing rock changes due to heat an or pressure
  4. 8. forms when something gets compacted or cemented together
  5. 9. process of finding relationships between rock layers and different locations
  6. 10. formed when molten rock cools and hardens
  7. 11. reminisce or trace of a plant or animal embedded in a rock