WAgrio Formation
WBacolet Formation
WBakken Formation
WBazhenov Formation
WBjorne Formation
WCaballos Formation
WCattamarra Coal Measures
WCerrejón Formation
WChipaque Formation
WCiechocinek Formation
WCleveland Shale
WDactyliocerassandstein Formation
WDoig Formation
WFómeque Formation
WFruitland Formation
WGuaduas Formation
WGuaratiba Group
WHorseshoe Canyon Formation
WItajaí-Açu Formation
WKimmeridge Clay
WKirusillas Formation
WKupferschiefer
WLos Molles Formation
WMacanal Formation
WOlder Parian Group
WPaja Formation
WPosidonia Shale
WTobago Volcanic Group
WVaca Muerta
WVilleta Group
WWasatch Formation
WWhitehill Formation
WWilcox Group