Across
- 1. the second largest time period
- 4. the newer rocks will be on top
- 5. the age of a layer is compared to others
- 7. the layer on the bottom
- 9. used for dating and correlation of the strata
- 10. the layer on the top
Down
- 2. some elements decay into daughter products
- 3. the remains of a prehistoric animal
- 6. the biggest time period on the scale
- 8. the time it takes for half of a layer to decay