Abstract: The Triassic in the Mount Songshan area is mainly distributed in Dajindian, Dongjindian and Lud.ian.It is represented by a sequence of purplish red to greyish green inland fluvial-lacustrine clastic rocks, with a total depositional thickneess up to 1203—1640 m, yielding abundant animal and plant fossils. This system displays conformable contacts with the underlying Permian Shiqianfeng Formation and is unconformably by the Tertiary. According to the lithologic features, biological assemblages and regional correlation, the Triassic of the area may be divided into the Lower Triassic Liujiagou Formation and Heshanggou Formation, the Middle Triassic Ermaying Formation and Youfangzhuang Formation and the Upper Triassic Chunshuyao Formation and Tanzhuang Formation.