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The graptolite strata of the Ordovician in the hongyi area of Jiangxi were first discovered by Zhang Qianshen and others(1964). Subsequently, the Early Ordovician graptolite strata were report by Xiao Chengxie and others(1975) from Niupiwan-Niupilong at Guobu of Chongyi. From August to November, 1978, Xiao Chengxie, Xia Tianliang, Wang Zhaoyun and Zhou Chonggui made a detailed survey and mapping of the Ordovician Zhangmuqu section at Guobu and Baishi'ao section at Sishun, with a systematic collection of graptolites; in 1982, Xiao Chengxie, Chen Hongye and Xie Wenwei make a further investigation into the Baishi'ao section at Geobu, Baishi'ao at Sishun, etc., making observation on the Ordovician section and supplementary collection of graptolites. Later, the writers selected the better-preserved graptolite specimens from those collected in abundance by Xiao Chengxie and others over the past years, with a systematic description of the graptolites from the Ningkuoan of Early Ordovician Assigned to 45 genera, 7 subgenera, 168 species and subspecies, including 3 new species.
The Ningkuoan graptolites in the Chongyi area had been reported for several times(Yang et al., 1983; Li, 198; Xiao et al., 1985 erected two new subgenera, namely Oncograptus (Proncograptus) and Cardiograptus (Procardiograptus), and some new species. Some of the above-mentioned graptolites are revised in the book.
As a whole, the Early Ordovician strata in Chongyi area belongs to the graptolitic facies with rich graptolies, especially those of the Ningkuoan, Whick are more abundant, with more genera and species forming a complete graptolite sequence, and may be divided into 10 graptolite zones, providing valuable material for the precise correlation of the Ningkuoan graptolite zones with those of the same time in the world. On the other hand, the discovery of Isograptus together with its allied genera is of most essential significance to the exploration into some curcial problems such as the evolution, classification of graptolites. Statistics of the diversity of the graptolite fauna indicates that the high diversity just conincides with the major development stage of Isograptus and its allied genera, while the fauna with a lower diversity appeared in the replacement stage of the replacement stage of the faunas, in which the Anisograpti fauna, for example, was replaced by the Dichograpti fauna. Statistical data on changes of the graptolite fauna indicate that the fauna with a greater change appeared in Xinchang and Ningkuo stages and the Ningkuo and Hulo stages respectively; the latter is also the boundary between Lower and Middle Ordovician boundary between Llanvirnian and Llandelian, which represents the most distinct boundary in the development stage of organisms. In addition, this book also makes a detailed statistical analysis on the ningkuoan graptolite fauna in different places of the cirum-Pacific region, with their genera and species tabulated in a list for correlation. The common presence of many identical and some comparable in this and other place shows the close relationship among them. It also has been found thast in this region the Ningkuoan graptolite fauna is the most abundant among those of the circum-Pacific region. Moreover, this graptolite fauna can be taken as a typical representative of the Ningkuoan graptolites of the Pacific fauna.

 

 

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