全球中奥陶统及奥陶系第三个阶、大坪阶的界线层型剖面和点位(GSSP)确定后,文中作者对宜昌黄花场剖面弗洛阶上部Oepikodus ewe带牙形刺生物地层序列进行再研究.通过对红花园组上部一大湾组下段一些关键层位中牙形刺样品的补充采集和牙形刺标本的系统检查,研究牙形刺属种垂向分布特征,修订一些牙形刺属种的首现层位.讨论Stolodus stola,Lundodus gladiatus,Oepikodus intermedius,Oepikodus communis,Trape-zognathusdiprion,Baltoniodus cf.B.triangularis等重要的多分子器官种分类问题.识别出Baltoniodus trian-gularis(Lindstr6m)的先驱:Baltoniodus cf.B.triangularis(Lindstrom)与Baltoniodus triangularis(Lindstrom)的区别.描述新建化石带属种,包括Baltoniodustriangularis(Lindstrom).认为Oepikodus evae带上部时限范围内并未见Oepikodus ewe分子,所以与国际地层指南(2000)关于间隔带和延限带的含义相悖.据此,厘定了原Oepikodus evae带的含义.并以牙形刺带分子首现为标志,将大湾组下段自下而上划分为3个间隔带,分别为:O.evae带,Trapezognathus diprion带和Baltoniodus cf.B.triangularis带.其中Trapezognathus diprion带和Baltoniodus cf.B.triangularis带为新建化石带.