Related Clues:

• Longish span of time
• Millennia on end
• Bronze and Iron, e.g.
• Ever so long
• Eternity, at Eton
• Geological span
• '-- Flux'
• Becomes drinkable, perhaps
• Time of operation
• Grows old gracefully
• Certain shift
• Geologic divisions
• Iron and Bronze, e.g.
• ''___ Flux''
• Billion years (Var.)