The Geologic Time Scale
Across
- 1. the parts of an era
- 4. an animal with a backbone
- 7. a warm blooded vertebrate that gives live birth
- 8. a time in which many species go extinct at the same time
- 10. the last era
- 11. scaly skin and lay tough leathery eggs
Down
- 1. the first era
- 2. animals without backbones
- 3. the three long units between Precambrian time and the present
- 5. lives in water and on land
- 6. the period of the humans
- 7. the middle era; time of the dinosaurs
- 9. the time of T-Rex