ch , ▁though ▁these ▁terms ▁are ▁now ▁ob sole te . ▁ ▁Out cro ps ▁The ▁rock ▁succession ▁is ▁exposed , ▁along ▁the ▁coast ▁sout heast ▁of ▁St ▁David s ▁and ▁in ▁particular ▁at ▁Sol va ▁where ▁the ▁out c rop , ▁though ▁largely ▁conce aled , ▁continues ▁in land . ▁A ▁cl iff ▁section ▁at ▁P orth ▁y ▁Rh aw ▁west ▁of ▁Sol va ▁provides ▁the ▁type ▁section . ▁Further ▁out cro ps , ▁though ▁less ▁well ▁exposed , ▁occur ▁n ortheast ▁of ▁New g ale ▁and ▁again ▁in ▁the ▁Wolf ' s ▁Castle ▁area . ▁ ▁Lith ology ▁and ▁strat ig raph y ▁The ▁Group ▁compr ises ▁over ▁two ▁hundred ▁meters ▁thick ness ▁of ▁mud st ones ▁and ▁sand st ones ▁together ▁with ▁a ▁bas al ▁con gl omer ate . ▁The ▁sand st ones ▁have ▁been ▁laid ▁down ▁as ▁tur bid ites . ▁Some ▁of ▁the ▁mud st ones ▁contain ▁t uff ▁hor iz ons ▁whilst ▁many ▁are ▁py rit ous ▁and ▁have ▁been ▁equ ated ▁with ▁the ▁C log au ▁Form ation ▁which ▁out cro ps ▁near ▁Har le ch , ▁both ▁indicating ▁that ▁the ▁floor ▁of ▁the ▁Wel sh ▁Bas in ▁was ▁o xygen - po or ▁and ▁the ▁waters ▁were ▁becoming ▁deeper . ▁Tr il ob ite ▁foss ils ▁are ▁recorded ▁throughout ▁the ▁sequence ▁whilst ▁the ▁sand st ones ▁of ▁the ▁upper ▁M ene v ian ▁contain ▁bra chi op od ▁foss ils . ▁ ▁References ▁ ▁Category : C amb rian ▁System ▁of ▁Europe ▁Category :