Abstract: Refitting of chipped stone artifacts is an increasingly common research method in China. Grouping artifacts into raw material units is always the first step as the preparation for refitting. Refitting studies are very time consuming and sometimes only little is found to be fitted together. However, the units formed in the refitting process still yield useful information. We discuss minimum analytical nodules (MAN) and their analysis approach (MANA) as a means of further understanding site formation process, technological organization and mobility at the Xujiacheng site. The site buried in the Malan Loess overlying the second terrace of the Shuiluo River in Zhuanglang County, Gansu Province. Archaeological materials were mainly unearthed from the 4th and 5th layers. The assemblage used in this paper focuses on the 346 stone artifacts which were unearthed from the 4th layers. 11 different raw material nodules were identified including 124 stone artifacts. The minimum analytical nodules analysis shows that the distribution pattern of stone artifacts in the main archaeological layers were resulted from in situ stone flaking and retouch. The interruption is much stronger on the border between different layers. The stone artifacts have strong expedient characteristics. Basing on the limited area, it is difficult to separate different types of activity areas within the site. The MAN could not be refitted completely, suggesting some artifacts were moved in or removed from the site. The implications are that occupants of Xujiacheng primarily employed relatively short foraging trips around the local site, and there were likely several living centers coexisted in this area. MANA is applicable to assemblages that contain materials which are highly variable in color and texture. Limited by the lithic materials which were dominated by quartz and granite and small excavated area which is around 20m2, this research does not show all the potential of MANA. Future studies should combine all potentially useful methods together as a means of building more robust theory to get more information on lithic technology, site formation, spatial organization and human mobility.

Key words: Xujiacheng Paleolithic site, Minimum Analytical Nodule Analysis, Site formation, Spatial utilization, Organization of mobility