Across
- 2. 541-252 million years ago, first amphibians and fish
- 3. Second largest time period
- 5. Smallest time period
- 6. 251.9 to 66.0 million years ago, age of the dinosaurs
- 7. Second to last smallest time period
Down
- 1. Representation of time based on rock record of earth
- 4. 66 million years ago, evolution of aniamls
- 8. Largest time period