Huang Baoren, Huang Xinggen
The Ostracoda recorded in this paper was collected by Huang Xinggen etc from the second terrace of southern bank of Sanggan River near southeastern Wenquantun Village and southwestern Jijiaying Village of Zhoulu County of Hebei Province, during Their surveying earthquake geology in this river valley in 1969-1970(Fig.1).The Ostracode fossils identified by the writers are included in 5 families, 9 genera, 12 species, among them 1 new species and 1 uncertain species. The associative Gastropoda identified by Yi Wen are also listed in the stratum table.According to the sediments and the fossil vertical distributions, the section can be divided into 3 segments in descending order as following (Fig.2, Tab.1):III segment, including 1-4 beds, subclay to subsandyclay, absent ostracodes.II segment, including 5-10, 17 and 11 beds, sediments rather fine, various small beds, strong curved structure, with abundent ostracodes.I segment, including 12-16 beds, main silt, the age of upper bed is 11030 ± 150 years according to 14C. Absent ostracodes, but yield some Gastropoda (Fig.2, Tab.1).Abundent fossil ostracodes are yield in the curved strata. Their genera belong to living forms which live in fresh water in Asia, Europe and North America.Their geological range are from Cenozoic era to recent.Cypris pubera Muller was first known in recent fresh water in Britsh, and was found recent water in Xizang too. Genus Notodromas occurred in the Quaternary of Qingzang Plateau and in the recent ditches in Hengduang Mountain.According to the living ecology of these fossil ostracode genera the deposit environment of curved strata undoubtedly belongs to continental fresh water and in rather cold weather.The age of the curved strata is slightly less than 11030 ± 150 years by 14C and belong to late Pleistocene according to the stratum sequence and fossil ostracodes. This strata was first named the Jijiaying Formation by the writers.
