Across
- 2. The first amphibians appeared in this period
- 3. Arthropods started to colonize terrestrial biomes during this period
- 4. The era of fishes
- 6. The first mammals appeared in this period
- 9. The era of reptiles
- 10. Trilobites appeared in this period
Down
- 1. The first reptiles appeared in this period
- 5. The first birds appeared in this period
- 7. The era of mammals
- 8. The greatest mass extinction occured at the end of this period