The classical model of fluvial facies is constructed based on the two followingassumptions: 1) the river course is dominantly controlled by the bankfull discharge,and 2) the helicoidal flow is fully developed. However, investigations of modernsedimentary environments show that the discharge of the meandering stream ischangeable and that the flow around meander bends is not completely helicoidal.So the sedimentary patterns of rivers are highly varied various. The ancient steppedpoint-bar sediments are well developed in the Quan-3 Member in the SongliaoBasin. They are characterized by the development of two sequences of point-bardeposits which are in abrupt contact and separated by the purple-red or variegatedmudistones. The lower point bar deposits, 2--5m thick, show a normal rhythmsimilar to the classical model; the upper point-bar deposits also show a normalrhythm but contain more clay and the bedding is less developed.