Across
- 4. the fauna from the Proterozoic eon
- 5. The oldest fossil
- 6. Formed during the Hadean eon
- 7. The smallest division of geologic time
- 10. The first age of the Phanerozoic eon
- 11. the gas released by Cyanobacteria
Down
- 1. The second eon
- 2. the age of reptiles
- 3. the period with an explosion of biodiversity
- 5. … Earth, when temperatures dropped during the Proterozoic
- 8. The first eon
- 9. The age of mammals