THE CAMBRIAN AND ORDOVICIAN STRATA IN THE QUEERQUEKE AND YAERDANG MOUNTAINS, XINJIANG

In 1981, the authors measured complete and continuous Cambrian and Ordovician sections and collected a lot of fossils in the Queerqueke and Yaer- dang mountains in Xinjiang. On the basis of fossil assemblages and lithologic associations, stratigraphic division and correlation were made. The deposition that took place between the Cambrian and Ordovician in the area was contin- uous. In the sections the authors discovered the Jiangnan-type fauna——the Late Cambrian Hedinaspic-Charchaqia-Lotagnostus-Westergaardites assemblage ——and the Early Ordovician Hysterolenus zone, which confirms that the contact betweeen the Upper Cambrian and the Lower Ordovician is conforma- ble. The actual materials show that the Cambrian and Ordovician strata in the area are completely developed, distinct in sequence and simple in structure. Therefore, the area is one of the ideal areas for studying the Cambrian and Ordovician strata and their boundary.