Abstract: The Nihewan basin (senso lato), which has the most concentrated evidence for the earliest human dispersal to East Asia, is the key region for study of the relationship between early hominin evolution and environment in North China. However, research in past decades was concentrated in the eastern part of the basin. Yuxian basin, which preserves fluvio-lacustrine deposits and early human cultural remains, is located in the southeastern part of the Nihewan basin. From 2015, a systematic investigation was conducted by a team from the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Hebei Provincial Institute of Cultural Relics, and Yuzhou Museum. Many Paleolithic sites and archaeological remains were discovered from Jijiazhuang town, Yuxian basin. This paper gives a preliminary report on the Jijiazhuang site(JJZ) complex which was excavated in 2016. The newly discovered Jijiazhuang site complex (JJZ-A, JJZ-B, JJZ-C, and JJZ-D) is located in the north part of Jijiazhuang town in the Yuxian basin. It was discovered in 2003 and was excavated in 2016. A total of 76 m2 was exposed, with 190 stone artifacts and 178 fossil fragments recovered from the site. The stratigraphic profile comprises fluvio-lacustrine deposits of browngrey, brown-yellow, grey-green, and grey-black fine sand, silt, and clay, which is capped by loess. The archaeological materials were unearthed from the brown-grey and brown-yellow fine sands and silt. Study of the multiple evidence from archaeological materials (particularly the artifact conditions, debitage size distribution, orientation analysis, and inclination) from JJZ-B site indicates that the archaeological deposits were buried rapidly in shallow lake margin deposits of fine sands and silts that were minimally disturbed and subjected only to relatively low energy sheet wash. Lithic raw materials were procured ca. 6 km north of the site, with volcanic lava dominating the rock types, and siliceous dolomite and chert less common. Artifacts in the assemblage are relatively small to medium in size. The flaking technique is direct hard hammer percussion, although many small flake butts display a lip that suggests soft hammer flaking was probably used by the early humans. Modified pieces appear to be casually retouched by direct hammer percussion. The JJZ lithic assemblage shows relatively advanced technology compared with the Mode 1 industries in the Early Pleistocene assemblages in the Nihewan basin. The broken nature of the fossil fragments hinders an unambiguous identification of the species. Preliminary comparison with the stratigraphy in the Nihewan basin indicates that early humans colonized the site probably in the Middle Pleistocene. It can be inferred that the study of the Jijiazhuang site complex bears great significance on the research of human adaptive behavior and technological exchange in the Nihewan basin during the Middle Pleistocene.

Key words: lithtic artifacts; site formation; Middle Pleistocene; Jijiazhuang site complex; Yuxian basin