| Answer | Crossword Clue |
|---|---|
| AEON | Part of the earth's history |
| EON | Period in the earth's history |
| EON | Phanerozoic ... (current period in the earth's history) |
| PERMIAN | Period marked by the largest mass extinction in earth's history |
| AREA | Part of the earth's surface. |
| IONOSPHERE | Part of the earth's atomosphere. |
| SIAL | Part of the earth's crust |
| PLATE | Part of the earth's crust |
| PLATE | Part of the earth's outer layer |
