The successive accumulation of cultural layers in Zhongba and Zhongbaodao sites is unique in the Three Gorges Region, which is a result of joint action of nature and human activities. Zhongba and Zhongbaodao sites formed first on the paleo-alluvial fan or piedmont terrace to gradually evolved into on the river islands in the broad valley. The exceptional physiognomy and depositional condition are the natural base of successive development of the two sites′ cultural layers. The salt industry, planting and fishing activities that appeared here ever since a long time ago were the internal driving force of durative human activities, which constitutes the human factor of the successive deposits of cultural layers. The perceptions of resources and environment of “Zhongba Man” and “Zhongbaodao Man” were the results that interacted between mankind and environment during the long survival practice, and instead of hindering or interrupting the continuity of the two sites′ human activities, the flood layers or flood deposits contained in the cultural layers turned into the important physical factors in promoting or firming the successive accumulation of cultural layers. 
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