geologic time scale

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Across
  1. 3. age of the rock layers in actual numbers
  2. 4. the era when dinosaurs lived
  3. 9. small pieces of rocks being found in different rock layers
  4. 10. age of rock layers with no exact numbers
Down
  1. 1. what scientists think the first living organism is
  2. 2. divides the earth up by living organisms
  3. 5. rocks layers on the bottom and younger rock layers on the top
  4. 6. scientist that studies fossils and rock layers
  5. 7. amount of time it takes an isotope to make a daughter product
  6. 8. bones of old animals found in rock layers