. "Crossdale Mudstone"@en . . "stable"@en . "Sharp upper boundary placed at the change from the mudstone-dominated Crossdale Mudstone overlain by the Accerhill Sandstone, a thickly bedded sandstone-dominated succession."@en . . . "Mudstone with subsidiary sandstone. Stratified bedrock. Occurs onshore. Deposited during the Arnsbergian Substage - to - Chokierian Substage (Carboniferous Period) (327-323 Ma BP)."@en . . "Crossdale Mudstone"@en . "CROM"@en . "Mainly blocky grey to dark grey laminated and fossiliferous mudstone, which becomes fissile on weathering. The mudstone contains siderite mudstone lenses and nodules at some levels. There are several thin marine bands composed of dark grey, platy mudstone with scattered oblate carbonate septarian nodules. Thin beds of sandstone are present and notably common in the uppermost few metres."@en . . "327.0"^^ . "Crossdale Shales [Obsolete: use CROM]"@en . "Sharp basal boundary placed at the change from the sandstone-dominated Silver Hills Sandstone to the overlying mudstone-dominated Crossdale Mudstone."@en . "323.0"^^ . "Crossdale Mudstone Formation [Obsolete: use SILS, CROM]"@en . . "14 to 23m in Crossdale; estimated 165m in Dolphinholme area."@en . .