Across
- 3. A major division of geological time,
- 8. were marked by major
- 9. into periods
- 11. age of mammals
- 12. and early Mesozoic
- 13. a animal without a backbone
- 14. A major division of geological time that
- 15. on Earth and existed during the late
- 16. A division of geological time that is a
Down
- 1. age of reptiles
- 2. age of ancient life
- 4. into eras
- 5. a subdivision of an eon and is itself
- 6. of time the divisions on the geologic time
- 7. a animal with a backbone
- 8. of an era
- 10. A supercontinent that included most
- 11. in life on earth