Related Clues:

• It started about 2 1/2 million years ago
• Very primitive
• Early tool-making time
• When bronze was replaced, historically
• Archaeological period
• Barney and Fred's time
• It began with the Paleolithic period
• Caveman's era
• Pre-Renaissance period
• Where the wild things are?
• It started around 1100 B.C.
• It began in Europe around 1200 B.C.
• When the Flintstones lived
• Historic toolmaking period
• Neolithic period