| 许杰教授对笔石的研究 |
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| 引用本文：穆恩之.1986.许杰教授对笔石的研究[J].地球学报,8(1):5-20. |
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| 中文摘要:文章系统记述了许杰教授在笔石学研究领域内所做的大量工作:论述了他的名著《长江下游之笔石化石》的科学及实践意义;阐述了他在笔石地层、笔石演化分类、笔石体的复杂化、笔石的发源中心问题诸方面所做的突出贡献。 |
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| PROF. XU JIE'S RESEARCH WORK ON GRAPTOLITHINA |
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| Abstract:Prof. Xu Jie's(Singwu C. Hsu) a famous geologist and palaeontologist, has been studying stratigraphy and palaeontology for more than fifty years. His research work on graptolites with their related strategraphy is particuliarly important in building up a foundation for further study of the graptolites and the graptolite-bearing strata in China.Since 1930, Prof. Xu has published a series of valuable papers on grap-tolites, and also reported and described a great number of graptolite species and established many graptolitic formations and graptolite zones.In his monograph entitled "THE GRAPTOLITES OF THE LOWER YANGTZE VALLEY" (1934), the most imporatnt work on the graptolites of China, Prof. Xu described in detail more than 90 species and subspecies of Ordovician and Silurian graptolites belonging to 19 genera, all species with remarkable illustrations in very fine figures drawn by himself.The Tanchiachiao, Ningkuo, Hulo and Yuchian formations with graptolite zonations in southern Anhui and western Zhejiang proposed by Prof. Xu have formed the foundation for the study of Ordovician stratigraphy in south China, with the Tremadocian graptolites of the Tanchiachiao formation, the Arenigian and Llanvirnian graptolites of the Ningkuo formation, the Llandeilian and Caradocian graptolites of the Hulo formation and the Ashgillian graptolites of the Yuchian formation as the main representtiaves of the graptolite fauna of the S. China Type.In Central China (or the Yangtze Region), the Tremadocian graptoliets of the Ichang formation were first described by Prof. Xu (Hsu and Ma, 1948), who consequently established the Acanthograptus sinensis zone in the upper part of the formation, which includes the graptolites belonging to the grap-tolite fauna of the C. China Type. He also described the Silurian graptolites of the Kaochiapien formation in the Lower Yangtze Region and a few species from the Lung mac hi formation in the Upper Yangtze Region.In Northwest China Prof. Xu described two important Lower Ordovician graptolite faunas from Tsaidam, Qingkai and Guozigou, Xinjiang, both with closer relation to the graptolites of the Ningkuo formation of S. China,belonging to the S. China Type. In his study 18 forms belonging to 10 genera were described from the Lower Ordovician of Tsaidam with the following three characteristic features recognized. 1) This fauna comprises a considerable number of forerunners; 2) It consists of a number of thin and delicate forms; 3) It appears to bear a distinct regional character. His description also includes 55 Lower Ordovician species belonging to 16 genera of the Guozigou Area with three graptolite zones established in ascending order: 1) the T. (E.) approximatus zone, 2) the D. "protobifidus" zone and 3) the Oncograptus upsilon-Cardiograptus morsus Zone, among which the last graptolite assemblage zone is similar to the Isograptus caduceus zone of Texas, N. America, comprising the elements mainly of the Oncograptus zone (N5) and the Cardiograplus zone (N6) in association with some species of the D. abnorms zone (N4) and G. austrodentatus zone (N7) of S.China and Australia. Prof. Xu is of the opinion that the Oncograptus upsilon-Cardiograptus morsus zone as well as the I. caduceus zone is a peculiarly mixed zone, in which the graptolites are not endemic forms, but are immigrant from the faunal center located in S. China to Australia.Prof. Xu discussed thorougkly the evolution and classification of the families Phyllograptidae, Sinograptidae, Glossograptidae, etc. Based on the characters of the thecae and the arrangement of the stipes in Trigonograptus, he compared this genus with Phyllograptus and placed it in the family Phyllograptidae in 1934. Later in 1964, after a careful examination of the Trigo-noraptus specimens in relief, he found that the genus is composed of four stipes just as Pseudotrigonograptus, the latter being considered as syuomymous with Trigonograptus, and therefore he pointed out that Trigonograptus (recently replaced by Pseudotrigonograptus) is evolved from Phyllograpius due to the lateral expanansion in the apertural portion of the thecae. |
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