Related Clues:

• Long geological stretch
• A billion years, to Hubble
• Lake fish
• Low-voiced singer
• Dog's age
• Eternity, seemingly
• Long period of time
• A month of Sundays
• Type of fish
• Prolonged period
• L-o-n-g stretch of time
• Hardly a falsetto
• 'Nozze di Figaro' part for Dr. Bartolo
• Looooong time
• Extremely long time period