【作者】 徐光洪； 赖才根；

【Author】 Xu Guanghong (Yichang Institute of Geology and Mineral Resources,Chinese Academy of Geological Sciences) Lai Caigen (Institute of Geology,Chinese Academy of Geological Sciences)

【机构】 中国地质科学院宜昌地质矿产研究所； 中国地质科学院地质研究所；

【摘要】 <正>前言长江三峡东部地区三游洞群(王钰,1938,138页)历来被视为晚寒武世的"哑"地层。1979年徐光洪于该群顶部发现一层头足类化石层;1980年,地质科学院宜昌地质矿产研究所和地质研究所又在该群下部发现数层三叶虫化石层。该层所含的头足类化石在本区尚属首次发现,并且对研究头足类的演化发展和地层的划分对比方面,亦具有重要意义。本文仅对这些问题作些初步探讨。更多还原

【Abstract】 The Sanyoudong Group(Wang Yu,1938,p.138) widely distributed in t he Yangtze Gorge,was known as a"barren"stratigraphical unit until conodonts were found in 1978.Next year a cephalopod-bearing bed was discovered from the top of this gToup by Xu Guanghong.Further,in 1980 a few trilobite-bearing beds were found from the lower part of the same group,by both the Yichang Institute of Geology and Mineral Resources and the Institute of Geology.They also made a second collection of cephalopods.Now this group is subdivided into three formations—the Xilingxia,Wuduhe and Xinping Formations(in desdending order).The last formation contains middle Cambrian trilobites.更多还原