Across
- 12. The longest division of geologic time
- 14. the theory that the outer rigid layer of the earth is divided into a couple of dozen
- 17. the process of gradual change and events
- 19. preserved remains, impression, or trace
- 20. the process where organisms better adapted to their environment tend to survive
- 21. units of time in years
Down
- 1. Cenozoic,Mesozoic
- 2. a form of relative dating
- 3. first formulated in Darwin's book "On the Origin of Species"
- 4. chronological dating
- 5. The geologic age of a fossil {non specific}
- 6. the diversity in gene frequencies
- 7. various crystalline or glassy rocks
- 8. the changes of rocks
- 9. layers called beds or strata
- 10. forcing a body of igneous rock between existing formations
- 11. useful for dating and correlating the strata
- 13. eroded by wind, water, or other natural agents
- 15. The change in inherited traits over successive generations
- 16. a person who studies the history of life
- 18. the movement of magma onto the surface of the earth through volcano craters