Stone Age

The Stone Age was the first period in the prehistory of humankind, preceding the Bronze and Iron Ages and characterised by the creation and use of primitive tools, some of which had a point, and others a sharp edge for cutting. It was also during that period that humankind discovered fire and how to control it. (PROSE: A History of Humankind)

The First Doctor's first trip with Ian Chesterton and Barbara Wright was to Earth's Stone Age. (TV: An Unearthly Child)

A plot by the Prometheans involved using the ancestral memory of the image of the Sun to revert the minds of those on Earth back to the Stone Age. The Eleventh Doctor was able to reverse this by sabotaging the chameleon circuit in his TARDIS, so that the Blue Box image would be implanted into the ancestral memory of Earth's history. (COMIC: Hunters of the Burning Stone)

According to the Silence, they had ruled the Earth since the Stone Age. (TV: Day of the Moon)

The Twelfth Doctor chased, catching her up in the Stone Age. (PROSE: Dr. Twelfth)