Across
- 4. A measurement of time equal to a billion years.
- 6. Comparing two rocks without the exact numbers of age.
- 7. The rue that if something comes into layers of rock that is younger than everything it cuts.
- 8. A layer or layers of rocks.
- 9. Rocks that help you compare different rocks.
Down
- 1. Anything rock that is inside of another rock is older than the outer rock.
- 2. The rule that in layers of rock the bottom layer is oldest and top is the yougest.
- 3. Helps you find the exact age of rock.
- 5. Comparing two rocks with exact numbers of age.
- 10. Remains of an organism that are recognized to show a period of time.