Geologic Time

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Across
  1. 3. the minerals in groundwater replace the minerals that make up the bodily remains after the water completely dissolves the original hard parts of the organism
  2. 5. a process of fossilization in which mineral deposits form internal casts of organisms.
  3. 6. determined by using radiometric dating.
  4. 7. no longer existing
  5. 10. sequence of layers of sedimentary rock
  6. 12. 252-66 million years ago
  7. 13. where only a thin carbon layer is left on a piece of shale
  8. 15. DNA found in tar and/or ice
Down
  1. 1. occurs when the organic matter is completely replaced by minerals and the fossil is turned to stone
  2. 2. the age of a rock layer (or the fossils it contains) compared to other layers
  3. 4. beginning about 66 million years ago and extending to the present
  4. 8. a fossil that is useful for dating and correlating the strata in which it is found.
  5. 9. 541 million years ago
  6. 11. a fossil of a footprint, trail, burrow, or other trace of an animal rather than of the animal itself.
  7. 14. things preserved in "amber"