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根据对湖北宜昌王家湾、黄花场、分乡以及新近发现的远安苟家垭奥陶系与志留系界线剖面生物地层、层序地层和化学地层的综合研究将该区最晚奥陶纪到最早志留纪的化石带自下而上重新厘定为Nankinolithus带,Dicellograptus complexus带,Paraorthograptus pacificus带,Nor-malograptus bohemicus-N.extraordinarius带,Hirnantia-Kinnella带,Glyptograptus? persculp—tus带,Akidograptus ascensus带,Parakidograptus acuminatus带和Orthograptus vesiculosus带,其中Paraorthograptus pacificus带可分为Pararetiograptus sinensis亚带,Tangyagraptus typicuas和Diceratograptus mirus亚带。指出目前尚无可靠证据证明国际奥陶系与志留系界线层型剖面,即英格兰Dob’s Linn剖面P. acuminatus带底部与该种首次出现（FAD）的层位一致。建议将英国Ashipill统改为阶,内部分两个亚阶,其上部“Hirnantian”亚阶和O/S界线应分别下移到P.pacificus带底部和G.?persculptus带底界。前者的底界与晚奥陶世Nankinolithus带顶部海退事件（NRE）后海侵所形成的最大海泛面的位置基本一致;后者与古冈瓦纳超大陆中部冰盖快速消融所引起的全球海退/海侵时间（HRE）和铱、碳同位素异常以及海洋及大气地球化学状况的突然改变相吻合,?
According to the integrated study of biostratigraphy, sequence stratigraphy and chemical stratigraphy of the Wangjiawan, Huanghua, Yixiang, Yichang, Hubei Province and recently discovered Ordovician-Silurian boundary line of the Yuan’an Goujiaya Project, the earliest Ordovician in the area was the earliest The Silurian fossil zones were reconstructed from bottom to top as Nankinolithus zone, Dicellograptus complexus zone, Paraorthograptus pacificus zone, Nor-malograptus bohemicus-N.extraordinarius zone, Hirnantia-Kinnella zone, Glyptograptus persculpus tus zone, Akidograptus humus zone, Parakidograptus acuminatus and Orthograptus vesiculosus, among which Paraorthograptus pacificus can be divided into Pararetiograptus sinensis, Tangyagraptus typicuas and Diceratograptus mirus. It is pointed out that there is no reliable evidence that the boundary line between the Ordovician and Silurian stratigraphic stratigraphy, that is, the bottom of the P. acuminatus belt in the Dob’s Linn section of England, is consistent with the first occurrence of this species (FAD). It is proposed that the British Ashipill be changed into an order with two sub-levels in its interior. The upper “Hirnantian” suborder and the O / S boundary should be moved downwards to the bottom of P.pacificus and to the bottom of G.?persculptus, respectively. The bottom boundary of the former is basically consistent with the position of the largest sea surface formed by transgression after the NRE of the Nankinolithus belt in the Late Ordovician. The latter is similar to that of the global sea surface caused by rapid melting of the Gondwana supercontinent Recurrence / transgression times (HREs) coincide with abrupt changes in iridium, carbon isotope anomalies, and ocean and atmospheric geochemistry.