Across
- 4. compare ages of rock to other rocks around
- 8. slow change of living things over time
- 9. theory of origin of universe-13.7bya
- 10. hallow area in sediment
- 14. supercontinent
- 15. preserved remains or traces of living things
- 16. covers 88% of earth history
- 17. break in the earth's crust
- 19. at least 50% of the species die out in a short amount of time
- 20. solid copy of the shape of the organism
Down
- 1. lava hardens on the surface
- 2. 1.3 billion years-dates old things
- 3. exact number of years since rock was formed
- 5. record of life forms and geological events in Earth’s history
- 6. represents a type of organism that only lived briefly
- 7. lave cools beneath the surface
- 11. minerals fill in spaces and preserve it
- 12. information gathered about organisms past life
- 13. studies fossils and classifies them
- 18. hard-shelled animals that make great index fossils