Across
- 2. the three long units between Precambrian Time and now
- 3. the pieces that make up Earth's outer layer
- 6. magma that has pushed itself into rock that cooled and hardened
- 7. study of the structure of Earth and the forces that make and shape Earth
- 8. the very slow movement of plates
- 9. molten material under Earth's surface
- 12. states that Earth's plates move slowly in various directions
- 16. break in Earth's crust
- 17. warm blooded vertebrate that feeds its young milk
- 18. series of processes that builds, destroys, and changes rocks
Down
- 1. what magma becomes when it reaches Earth's surface
- 2. the breaking down of rocks
- 4. lava that cools and hardens on a rock surface
- 5. tiny particles of matter
- 7. record of life forms and geologic events in Earth's history
- 10. an animal that lives of both land and water
- 11. subdivision of eras
- 13. half the time it takes for radioactive atoms to decay
- 14. organisms with scaly skin and lay tough, leathery eggs
- 15. piece of rock contained in another rock