Possible Clues:

• Fabled submerged city
• Pursuing retreating army, Stalin devastated continent?
• Connolly described some, in a work of some promise
• In Greek legend, a beautiful island buried in the sea
• Lost island from New Testament, one in map collection
• Fabled lost continent
• Sunken naval power, per Plato
• Down under island?
• Books I found among maps showing sunken land
• Legendary vanished island — mythical place