"Bude Sandstones [Obsolete: use BF]"@en . "Morchard-Type Culm [Obsolete: use BF]"@en . . "BF"@en . . . . . "The upper boundary is taken at an angular unconformity, where breccias of the Exeter Group rest upon sandstone and subordinate mudstone of the Bude Formation."@en . "Sandstone with subsidiary mudstone and siltstone and trace ironstone. Stratified bedrock. Occurs onshore. Deposited during the Langsettian Substage - to - Bolsovian Substage (Carboniferous Period) (319-310 Ma BP)."@en . . "Bideford Formation"@en . "stable"@en . . . . "310.0"^^ . . "On the north Cornwall and north Devon coast, the base is taken at the top of the Hartland Quay Shale, the uppermost of the named goniatite-bearing mudstones in the underlying Crackington Formation. Inland, where the Hartland Quay Shale cannot be mapped in pervasively folded terrain, as it is too thin, the base is taken at the incoming of softer, siltier thick-bedded sandstones of the Bude Formation above the dominantly thin- to medium-bedded sandstones and mudstones of the underlying Crackington Formation. \r\n\r\nIn north Devon, south of Bideford, the base is taken at the sharp incoming of over 100 m of grey mudstones and siltstones with two thin anthracitic coals (culm) above the cross-bedded thick-bedded Cornborough Sandstone that caps the top of the underlying Bideford Formation. Thick-bedded sandstone with internally massive beds typical of the Bude Formation, appear above these mudstones and siltstones."@en . "At least 1290 m calculated on the north Cornwall and north Devon coast."@en . "Middle Culm [Obsolete: use BF, SME]"@en . "Bude Formation"@en . . "Cockington Beds [Obsolete: use CKF, BF]"@en . "Grey thick-bedded, somewhat argillaceous and silty sandstones, in laterally discontinuous internally massive beds 1-5m thick and commonly amalgamated into units up to 10m thick. When weathered the sandstones become buff and friable. Very thick beds of slumped and destratified strata are also present. Grey mudstones occur as interbeds up to 1m thick but locally packets of darker mudstone up to 20m thick with thin ironstone beds and bundles of thin sandstones are present, especially in the upper part of the Formation. Five named beds of black sulphurous \"shales\" with goniatite-bearing calcareous nodules occur within the Formation. Thin units of thin- to medium-bedded siltstones with Xithosurid trails are also present. \r\n\r\nDeposited in a large-scale freshwater lake situated on a broad shelf. Sandstone deposition was within storm wave base and by river-fed turbidity currents. Also, there was probably deltaic progradation across part of the basin late in its development. The goniatite-bearing mudstones represent periodic marine invasions."@en . . . "319.0"^^ . . "Greencliff Beds [Obsolete: use BF]"@en . "Bude Formation"@en .