Geological time scale

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Across
  1. 2. 1st eon of earth, Earth looked "hellish" at this time.
  2. 5. longest time frame totaling half a billion years or more.
  3. 6. period where plants dominated the Earth to the point that there wasn't enough Carbon Dioxide to keep the plants alive.
  4. 9. is a method used to determine the age of rocks and fossils by comparing them to other materials in their vicinity.
  5. 10. Each totaling millions of years, 99 defined.
Down
  1. 1. Gaps in the geologic record due to erosion. They represent missing time in the rock layers.
  2. 3. Totaling tens to one hundred million years (Jurassic)
  3. 4. is a method used to determine the exact age of a rock or fossil in years.
  4. 5. Each totaling tens of millions of years, 34 epochs.
  5. 7. Each totaling several hundred million years (Cenozoic)
  6. 8. the youngest rocks are at the top, and the oldest rocks are at the bottom.