"Culver Chalk Formation And Portsdown Chalk Formation (Undifferentiated)"@en . "Bedrock. Occurs onshore. Formed during the Campanian Age (Cretaceous Period) (83.7-72.2 Ma BP)."@en . . . . . "stable"@en . . . "CPCK"@en . "Culver Chalk Formation And Portsdown Chalk Formation (Undifferentiated)"@en . . "72.2"^^ . . "83.7"^^ .