| Answer | Crossword Clue |
|---|---|
| IRONAGE | Period marked by increased smelting |
| BRONZEAGE | Period marked by copper use |
| ERA | Period marked by distinctive character |
| PLATEAUAEON | Geologic period marked by tablelands? |
| BOOMORBUST | Like a period marked by economic extremes |
| PERMIAN | Period marked by the largest mass extinction in earth's history |
