Related Clues:

• Narrow, steep-sided valley
• Indy 500 area
• Pendulum locale
• Kind of boss
• Coal source
• Orchestra setting
• Unwelcome fruit part, perhaps
• Unfathomable cavity, e.g.
• Large gully
• Deep valley
• Poe's pendulum setting
• Columbia River highlight
• Deep gorge
• Pendulum's place
• Orchestra's place, sometimes