| Answer | Crossword Clue |
|---|---|
| MIOCENE | Period of the Age of Mammals. |
| JURASSIC | Middle period of the Age of Dinosaurs |
| MESOLITHIC | Characteristic of a transitional period in the Stone Age |
| TRIASSIC | Period when mammals first appeared |
| JURASSIC | Period when birds and mammals appeared |
| TEENS | Coming-of-age period |
