Possible Clues:

• Incomplete map collection somehow isn't showing ancient continent
• Objectors adopting URL, say, of Fantasy Island
• Legendary long-lost island
• Fictitious place social worker discovered in a sick list
• Mythical continent
• Fictitious place in book about redistribution of tin
• Island once shown by name? It is back in maps
• Mythical lost land
• Fabulous place TV department reviewed in maps
• Fabled sunken realm