Related Clues:

• 'This holy, hard one is heavy (5)'
• 'A holy one, but hard (5)'
• The holy one is the hard one
• Sling ammo
• Castle-building material
• Director of 'JFK,' 'Nixon' and 'W.'
• Lake skipper?
• With 42-Across, time of cavemen
• See 5
• See 3
• See 1
• See 19
• See 21
• See 7
• See 23