<正>At about 173 ka BP of the late period of mid-Pleistocene, the second terrace of the river had been formed as a result of uplift happening in Shangshan area because of the cli-mate, sea level change and tectonic action. Between 173?75 ka BP, aeolian deposited on the terrace, a layer of reticulate red clayey soil about 80?100 cm thick deposited and developed under the warmer and higher temperature. In the last glacial period, the drop of the tem-perature and the decrease of the precipitation induced the dust-storms increased, A layer of Xiashu loess about 1.0?1.5 m thick accumulated on Shangshan terrace in the last glacial, which has the reticulate red clayey soil buried. At the beginning of the Holocene (11500 a BP?), temperature went higher gradually and precipitation got more, the pre-persons moved on the Shangshan terrace (11,400?8600 a BP), which is one of the most important archaeo-logical sites, and can connect the paleolithic culture with Neolithic culture. It could be as-sumed from the results that the lower reaches of the Yangtze River are the home of rice cul-tivation, too. The lower place to the west of the Shangshan site experienced the two cycles process of the fluvial facies and the lacustrine facies, indicating that the water source of the pre-historical Shangshan is the river water or lake water. Two AMS 14C age proved the water source disappeared more than 1000 years ago.
