. "Reef Limestone [Obsolete]"@en . . "330.9"^^ . . "GFLS"@en . . "Limestone with subsidiary dolostone. Stratified bedrock. Occurs onshore. Deposited during the Asbian Substage (Carboniferous Period) (337-330.9 Ma BP)."@en . "c.100m"@en . "Massive \"reef\" limestones overlain by dark grey mudstones and thin argillaceous limestones of the Teilia Formation."@en . "337.0"^^ . "Knoll reef limestones comprising highly fossiliferous, massive, pale, fine-grained, recrystallised and locally dolomitised limestones with abundant calcite-lined former cavities with internal geopetal sediment (stromatactis). Contains a rich brachiopod and goniatite fauna. During the time of late Asbian carbonate platform development in North Wales a series of knoll reefs formed along, and serve to define, the platform margin. The knoll reef facies interdigitate with platformal facies on one side, and resedimented basinal facies of the Craven Group on the other."@en . . "Knoll Reef [Obsolete: use GFLS]"@en . . . . "Graig Fawr Limestone Member"@en . . "Graig Fawr Limestone Member"@en . "stable"@en . "Entry of massive \"reef\" limestones above well bedded Loggerheads Limestone; also passes laterally southwards into the Loggerheads Limestone, and passes laterally northwards into the Prestatyn Limestone Formation (Craven Group)."@en . .