Possible Clues:

• Rock on the Rhine
• Sounds as if the girl might lie on the rocks
• Siren learning with the French individual
• Fateful singer gets look about the French island
• Role for Marilyn
• Siren, said to dwell on a rock at the edge of the Rhine south of Koblenz
• Siren of German legend who lured boatmen in the Rhine to destruction
• The Spanish oiler went round this on the Rhine
• Sort of lonelier nameless nymph
• Rock singer learning what Romanians use for money