扬子地台中部兰维恩至兰代洛世几丁虫生物地层

本文系统介绍了湖北宜昌普溪河、黔北遵义和四川酉阳丁市兰维恩世至兰代洛世地层中几丁虫的分布发育规律，指出扬子地台中部兰维恩世至兰代洛世的几丁虫自下而上可划分为Ｃｙａｔｈｏｃｈｉｔｉｎａｊｅｎｋｉｎｓｉ，Ｃｏｎｏｃｈｉｔｉｎａｃｏｎｕｌｕｓ，Ｅｉｓｅｎａｃｋｉｔｉｎａｕｔｅｒ和Ｌａｇｅｎｏｃｈｉｔｉｎａｄｅｕｎｆｆｉ等４个生物带，讨论了各几丁虫生物带的时代意义，此外还对几丁虫化石进行了图示和描述。

LLANVIRIAN AND LLANDEILIAN CHITINOZOAN BIOSTRATIGRAPHY IN CENTRAL YANGTZE PLATFORM

Systematic study of Llanvir to Llandeilo chitinozoans collected from Puxihe of Yichang,W.Hubei,Dingshi of Youyang,SE Sichuan and Hailong of Zunyi,N.Guizhou in Central Yangtze platform,shows that 4 chitinozoan biozones:Cyathochitina jenkinsi,Conochitina conulus,Eisenackitina uter and Lagenochitina deunffi biozones can be recognized in ascending order.The stratigraphic range of each biozone,its assemblage characteristics and relationship with graptolite and conodont biozones and equivalent chitinozoan biozones in other areas of the world are discussed.It is found that the base of E.uter biozone is basically concided with the FAD of Nemagraptus gracilis at Puxihe section,while the latter has been suggested as a mark to define the base of revised Caradoc Series.