Shuidonggou is one of the most important Upper Paleolithic sites in North China. Due to the presence of rich human remains,animal fossils,abundant sporopollen and unique geological sequence,it is the type site for Late Pleistocene to Holocene human occupation and environmental change in the Ningxia-Inner Mongolia region. Many scholars suggest that the site should be named the "Shuidong-gou Formation" of Late Pleistocene in North China. Dating results indicate that ancient human activities at the site took place 30―24 ka (Marine Isotope Stage MIS 3). The climate at that time was warmer and moister than present day,and adequate precipitation led to the formation of water pack depressions where broad-leaf trees and sparse forest vegetations,as well as herbivorous animals flourished,mak-ing the area suitable for early human hunting,gathering and survival. The Neolithic human occupation happened 9―5 ka at the site,while similar environmental conditions with MIS3 occurred. The absence of human activity record in the region during the Last Glacial Maximum (MIS2) suggests that the envi-ronment was too harsh for humans to live there.
