Fossils and Geologic Time Scale

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Across
  1. 4. bones, teeth, and shells can be preserved this way
  2. 7. 'recent life', what earth looks like today
  3. 8. this happens when water dissolves the original solid material and replaces them with mineral matter such as calcite,silica, pyrite,and hematite
  4. 9. petrified wood is the most well known of this process
  5. 13. the earliest era between the three; where life first started on earth
  6. 15. special fossils called this indicate to geologists the boundaries in geologic time
Down
  1. 1. most accurate form of dating, also called radiometric dating
  2. 2. this law helps scientists determine the age of fossils,relatively speaking
  3. 3. the process by which all substances of plants and animals decay,except carbon
  4. 5. having no living members; no longer in existence
  5. 6. if two different rock strata in different areas on Earth contain the same index fossils,then the strata are probably the same age
  6. 10. this can trap animals and preserve their bodies to where we can see it today
  7. 11. provides indirect evidence of life in the past rather than the body of the animal itself
  8. 12. this is excreted from certain plants, which is thought to protect them from insects and seals off plant injuries
  9. 14. dinosaurs lived in this era