Answer:

pliocene

Answer	Crossword Clue
PLIOCENE	Tertiary Period epoch
PLIOCENE	About 5 million years ago
PLIOCENE	Of a geological period.

PLIOCENE	Geological period.
PLIOCENE	Geological epoch
PLIOCENE	Epoch from 10 to 2 million years ago
PLIOCENE	Epoch from two to five million years ago
PLIOCENE	Epoch when the landmasses of North and South America joined
PLIOCENE	Last epoch of the Tertiary period