| Answer | Crossword Clue |
|---|---|
| EONS | Geologist's time scheme. |
| ERA | Geologist's time |
| EON | Geologist's time period |
| ERA | Geologist's time division |
| isorhythmic | in ancient prosody, equal in the number of time-units for thesis and arsis, as dactyl, spondee, anapaest; (in medieval motets) having a strict scheme of repeated rhythm independent of melodic repetition |
