Abstract: The Luanhe River, 1,200 kilometers long, flows through the Yanshan mountains into the Bohai Bay, with an annual water discharge of 4.55 billion cubic meters and sediment discharge of 19 million tons. An alluvial fan-delta, covering an area of 2,500 square kilometers, is formed at the foot of Yanshan mountains along the shore of Bohai Sea. The northern part of the complex consists of two upwairdfining post-glacial sedimentary sequences,in which no marine faunas are found; while in the southern part, the post-glacial formations are made up of an upward-fining sequence in the lowerpart and an upward-coarsing sequence in the upper part, both containing marine faunas. The lower part of the post-glacial sequence was deposited in the courseof transgression. With the rise of sea level and the datum plane in post-glacial time, sea water advanced into the land along the river valley. At the same time, accumulation of retrogressive deposits took, place in the lower reaches that filled in the river valley and formed the lower part of the sequence. The distance covered by retrogressive accumulations far excee dedthat of sea water. Marine faunas can only be found in the sequence within the reach of sea water, beyond which are continental beds without such fossils. Therefore, the transgressive sequences in the valley, with or withoutmarine faunas, are formed in a unified sedimentary process, so that the fluvial deposits in the north and the deltaic deposits in the south that constitute the upper part of the postglacial sequence are genetically related.