Yehlangian,Upper Permian or Lower Triassic?

<正> The Yehlangian of Ting and Graban includes the Paoan shale,the Yülungshanlimestone,the Feihsienkuan shale and the Sanchiao limestone.In their opinion theseformations would represent the Upper Permian of south-western China.The presentpaper tries to show that both by their stratigraphical relation and their faunal contentsthe Yülungshan limestone and the Feihsienkuan shale belong undoubtedly to the LowerTriassic and that the Sanchiao limestone is much younger,probably of Upper Triassicage.The Paoan shale is the only true Upper Permian formation.If the termYehlangian is to be retained,it should be redefined as a general term for the LowerTriassic of south-western China,including only the Yülungshan limestone,the Feihsien-kuan shale and their exact equivalents.