"Dryden Flags [Obsolete: use DRY]"@en . . "Dryden Shales [Obsolete: use DRY]"@en . "Change from dominantly arenaceous to dominantly argillaceous lithologies."@en . . . . "Dryden Flags Formation"@en . . "412.4"^^ . . "410.5"^^ . . . "DRY"@en . "Dryden Formation [Obsolete: use DRY]"@en . "Dryden Flags Formation"@en . "Brownish green shales and siltstones with a few sandstone bands; contains interbedded chert and rhyolitic to andesitic lava and ash at NJ 494 277, near Windyfield."@en . "stable"@en . . . . . "Removed by erosion."@en . "Approx. 260 metres in type section, but not seen; probably approx. 800 metres present in Castlehill (NJ 515 283) area."@en . "Mudstone and siltstone with subsidiary andesite, chert, rhyolite and sandstone. Stratified bedrock. Occurs onshore. Deposited during the Pragian Age (Devonian Period) (412.4-410.5 Ma BP)."@en .