Related Clues:

• Deep crevice
• Backwoods parent
• Significant divide
• Yawning gorge
• A monster may have a big one
• "Gaping" gullet
• It's hard to get across
• Grand Canyon, notably
• It might be yawning
• Animal's gaping mouth
• Some breach, a small gorge
• Creature-feature opening
• Gaping pie-hole
• Huge difference between viewpoints, say
• Charles Martel's heading for great breach