Cro-Magnon

Cro-Magnons were a proto-human species. Circa 40000 BC, a Cro-Magnon tribe made first contact with a Neanderthal tribe.

The Fifth Doctor hoped to observe the point of first contact between the Neanderthals and the Cro-Magnons. He failed to witness the event, not realising that his observation of them was the cause of the first contact. (PROSE: Observation)