Abstract: The lithologic association of the Chuanlinggou Formation consists mainly of shales. According to the lithology and lithofacies association, vertical facies sequence and change in thickness, three areas may be distinguished: the northwest area, transitional area and southeast area. The lithologic association of the northwest area is composed mainly of mudstone with thin-bedded fine sandstone ,49-62m thick; that of the transitional area, mudstone and fine sandstone with two beds of medium-to coarse-grained sandstone varying in thickness from 60 to 240m, with a total thickness of 600m; that of the southeast area, mainly mudstone-shale,> 530m thick. Laterally they interfinger each other and their sedimentary environment belongs to the barrier island-lagoon system of microtidal coastal type (tidal range 0-2m).