Related Clues:

• Heading to north island get firm, factual type of evidence?
• Isolated location of Ballard is definite
• Specific; definite
• Solid cloud seen at first over island
• Study island material
• Sand and cement
• Study on Mediterranean island building material
• Building material for many on a Greek island
• Solid sort kept by bird near island
• Conservative wet, formerly keeping it real
• Solid Tory found on island
• Real civilisation, initially where Zeus was born
• Not abstract
• Real, not abstract
• Material giving firm centre when poured