Individual #Stone_Age  (archeology) the earliest known period of human culture, characterized by the use of stone implements
  instance of:  time_period
  part of:  prehistory
  part:  Eolithic_Age  the earliest part of the Stone Age marked by the earliest signs of human culture
  part:  Paleolithic_Age  second part of the Stone Age beginning about 750,000 years ago
  part:  Mesolithic_Age  middle part of the Stone Age beginning about 15,000 years ago
  part:  Neolithic_Age  latest part of the Stone Age beginning about 10,000 BC in the middle east (but later elsewhere)

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