Across
- 5. molten rock flowing out of a volcano
- 6. a large crater left by a volcanic explosion
- 7. mastodon, mammoth or sabretooth
- 9. rain or snow
- 12. violent or sudden
Down
- 1. the source of a river
- 2. time when oldest rocks were formed
- 3. the study of earth
- 4. bringing in a supply of water for farming
- 8. impressions of ancient creatures
- 10. animals that don't have backbones
- 11. molten material below the earth's crust