| Answer | Crossword Clue |
|---|---|
| ERA | Paleozoic or Precambrian |
| ERAS | Paleozoic and Precambrian |
| ERAS | Precambrian and Paleozoic |
| archaean | noting or pertaining to rocks of the Archeozoic portion of the Precambrian Era |
| archean | noting or pertaining to rocks of the Archeozoic portion of the Precambrian Era |
| paleozoic | Of, relating to, or denoting the era between the Precambrian eon and the Mesozoic era |
| azoic | (formerly) noting or pertaining to the Precambrian Era, esp. that part formerly believed to precede the first appearance of life; Archean |
