Abstract: Gansu Province is the first place in China where Paleolithic artifacts with clear stratigraphy were found. Most of these early finds were located in the eastern loess plateau, in the eastern part of the province. This report presents the result of a series of Paleolithic reconnaissance work conducted by the IVPP and the Gansu Provincial Institute of Archeology in 2009 in the Longxi Basin of the middle part of Gansu Province. Stone artifacts and mammalian fossils from 16 new localities were collected,14 of which were confirmed with clear stratigraphy and another 2 found in uncertain contexts with typical Paleolithic artifacts. Stone artifacts included flakes(n=96), chunks(n=64) and chips(n=33), followed by cores(n=26) and retouched items(n=8). Raw material was primarily quartz probably collected by ancient peoples from the adjacent riverbed. Hard hammer percussion was the main flaking technique, followed by bipolar flaking. Scrapers were modified on flakes by hard hammer percussion on a single surface. A small point with bifacial retouch was also found and through technological characteristics it exhibits close ties with the flake tool tradition in North China. Stratigraphic observations and preliminary AMS 14C dating suggests that these newly discovered localities were formed in two stage: L1S1(60/59～28 kaBP) and L1L1(27～10 kaBP). The middle part of Gansu Province is an important area that is abundant with Paleolithic sites. Among the 16 localities, the Xujiacheng1, Shixiakou1 and Shixiakou2 localities show the archeological value for further excavation from their clear stratigraphy and plentiful artifacts. In recent years almost 50 Paleolithic sites have been found in this limited area, and as a result it has become a key region of human dispersal and occupation in northwestern China during the late Pleistocene, which will provide valuable clues for interpreting human adaptive behavior, migration, and interaction with the environment in this area.

Key words: Paleolithic; Longxi Basin; Shuiluo River; Qingshui River; Late Pleistocene