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Conodonts as biostratigraphic tools for redefinition and correlation of the Cambrian–Ordovician Boundary

Published online by Cambridge University Press:  01 May 2009

J. F. Miller
J. F. Miller
Affiliation:
Geosciences Department, Southwest Missouri State University, Springfield, Missouri 65804–0089, U.S.A.
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Abstract

The Cambrian–Ordovician Boundary is recognized at different horizons on various continents by utilizing several fossil groups. Conodonts are abundant, diverse, and less provincial and facies-controlled than other fossils in this interval; many species are widespread and some are cosmopolitan. Strata representing the Cambrian–Ordovician Boundary interval from Asia, Australia, and North America can be correlated easily when those strata are from cratonal or shelf environments. Strata from slope facies have fewer conodonts, fewer taxa, and taxa may have different ranges compared with cratonal and shelf facies. It may be easier to correlate intercontinentally within cratonal/shelf facies than to correlate intracontinentally from cratonal/shelf facies to slope facies.

A new hierarchical arrangement of conodont interval zones and subzones is proposed for western North America. These include the Proconodontus tenuiserratus Zone, the P. posterocostatus Zone (new), the P. muelleri Zone (new), the Eoconodontus Zone (new, with Eoconodontus notchpeakensis and Cambrooistodus minutus Subzones), the Cordylodus proavus Zone (emended, with Hirsutodontus hirsutus, Fryxellodontus inornatus, and Clavohamulus elongatus Subzones), the Cordylodus intermedius Zone (new, with Hirsutodontus simplex and Clavohamulus hintzei Subzones), the Cordylodus lindstromi Zone (new), and Cordylodus angulatus Zone (new).

The boundary point for the base of the Ordovician System will be chosen so as to coincide with a correlatable conodont zonal boundary; other fossil groups will support correlation of this boundary point. Three alternative horizons are being considered. The base of the Cordylodus proavus Zone is the most distinctive but is regarded by some as older than is appropriate for the base of the Ordovician. The base of the Cordylodus intermedius Zone is recognizable by faunal changes in several evolutionary lineages at a level that is slightly younger than the presently recognized boundary in Australia, North America, and parts of Asia but slightly older than the base of the Tremadoc Series of Europe. The base of the C. lindstromi Zone can be recognized in most areas by the lowest occurrence of the nominate species, which is of questioned taxonomic validity and uncertain biostratigraphic utility; this horizon is closest to the base of the Tremadoc Series of Europe.

Choice of a stratotype section has been narrowed to the Cow Head Group in Newfoundland, eastern Canada; and to the Fengshan and Yehli formations in Jilin Province, northeastern China. The Cow Head Group was deposited on and near the base of the continental slope. Erosion by debrisslide breccias resulted in a significant hiatus near the boundary interval in the Broom Point sections, a condition contrary to guidelines for choice of boundary sections. This may be less of a problem in other sections, such as Green Point. The Dayangcha section in China was deposited on the outer part of a continental shelf and has acritarchs, conodonts, graptolites and trilobites. Additional study of the China section is needed to document fully the ranges of critical conodont taxa.

Type
Articles
Information
Geological Magazine , Volume 125 , Issue 4 , July 1988 , pp. 349 - 362
Copyright
Copyright © Cambridge University Press 1988

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References

Abaimova, G. P. 1971. New Early Ordovician conodonts from the southeastern part of the Siberian Platform. Paleontological Journal 5, 486–93.Google Scholar
Abaimova, G. P. 1972. Raschlenenie i korrelyatsiya Ordovikskikh otlozheniy yugo-vostoka Sibirskoy platformy po konodontam [Subdivision and correlation of Ordovician deposits from the southeastern part of the Siberian Platform based on conodonts]. Novosibirsk, Trudy Sibirskogo Nauchno-Issledovatel'skogo Instituta Geologii, Geofiziki i Mineral'nogo Syr'ya (SNIIGGIMS) 146, 65–7.Google Scholar
Abaimova, G. P. 1975. Rannerordovikskie konodonty srednego techniya r. Lena [Early Ordovician conodonts from the middle course of the Lena River]. Novosibirsk, Trudy Sibirskogo Naucho-Issledovatel'skogo Instituta Geologii, Geofiziki i Mimeral'nogo Syr'ya (SNIIGGIMS) 207, 137 pp., 10 pls.Google Scholar
Abaimova, G. P. 1978. Late Cambrian conodonts of central Kazakhstan. Paleontological Journal 12, 493–503, pls. VII–VIII.Google Scholar
Abaimova, G. P. & Markov, E. P. 1977. Pervye nakhodki konodontov Nizhnerordovikskoy Zony Cordylodus proavus na yuge Sibirskoy platformy [First-discovered Lower Ordovician conodonts from the Cordylodus proavus Zone on the southern Siberian Platform]. Moscow, Trudy Instituta Geologii i Geofiziki Akademii Nauk SSSR, Sibirskogo Otdeleniya 372, 86–94, pls. 14, 15.Google Scholar
Tai-xiang., An 1982. Study on the Cambrian conodonts from North and Northeast China. University of Tsukuba Science Reports of the Institute of Geoscience, Section B 3, 113–59.Google Scholar
Tai-xiang, An, Fang, Zhang, Wei-da, Xiang, You-qui, Zhang, Wen-hao, Xu, Hui-juan, Zhang, De-biao, Jiang, Chang-sheng, Yang, Lian-di, Lin, Zhang-tang, Cui & Xin-chang., Yang 1983. The Conodonts of North China and the Adjacent Regions. Beijing: Science Press. 223 pp., 33 pls.Google Scholar
Apollonov, M. K. & Chugaeva, M. N. 1982. Batyrbaisaiskiy razrez kembriya i ordovika v Malom Karatau (Yuzhnyy Kazakhstan) [Batyrbaisai section of the Cambrian and Ordovician at Malyi Karatau (South Kazakhstan)] Moscow: Izvestiya Akadamii Nauk SSSR, Seriya Geologicheskaya 1982 (4), 36–46.Google Scholar
Apollonov, M. K., Chugaeva, M. N. & Dubinina, S. V. 1984. Uppermost Upper Cambrian and Lower Ordovician in the Batyrbay Ravine; the Togusbay Suite along the Dongeleksay Stream. In Geology and Phosphorite in Maly Karatau Ridge, pp. 51–4. Guidebook for Excursion 045A, 27th International Geological Congress, Moscow.Google Scholar
Barnes, C. R. 1974. Ordovician conodont biostratigraphy of the Canadian Arctic. In Canadian Arctic Geology (ed. Aitken, J. D. Glass, D. J.), pp. 221–40. Calgary: Geological Association of Canada–Canadian Society of Petroleum Geologists, Special Volume.Google Scholar
Barnes, C. R. 1988. The proposed Cambrian–Ordovician global boundary stratotype and point (GSSP) in western Newfoundland, Canada. Geological Magazine 125, 381–414.CrossRefGoogle Scholar
Bruton, D. L., Koch, L. & Repetski, J. E. 1988. The Nærsnes section, Oslo Region, Norway: trilobite, graptolite, and conodont fossils reviewed. Geological Magazine 125, 451–5.CrossRefGoogle Scholar
Budge, D. R. & Sheehan, P. M. 1980. The Upper Ordovician through Middle Silurian of the eastern Great Basin. 1. Introduction, historical perspective and stratigraphic synthesis. Milwaukee Public Museum Contributions in Biology and Geology, No. 28, 26 pp.Google Scholar
Bultynck, P. & Martin, F. 1982. Conodontes et Acritarches de l'ordovicien inferieur et Acritarches du Silurien inferieur de la partie septentrionale de la cordillere argentine. Bulletin de l'Institut Royal des Sciences Naturelles de Belgique. Sciences de la Terre, Brusseles 53 (4), 1–21, 2 pls.Google Scholar
Burrett, C. F. & Findlay, R. H. 1984. Cambrian and Ordovician conodonts from the Robertson Bay Group, Antarctica and their tectonic significance. Nature 307, 723–25.CrossRefGoogle Scholar
Jun-yuan, Chen (ed.) 1986. Aspects of Cambrian–Ordovician Boundary in Dayangcha, China. Beijing: China Prospect Publishing House. 410 pp., 98 pls.Google Scholar
Jun-yuan, Chen & We-li., Gong 1986. Conodonts. In Aspects of Cambrian-Ordovician Boundary in Dayangcha, China (ed. Jun-yuan, Chen), pp. 93–223, pls. 17–54. Beijing: China Prospect Publishing House.Google Scholar
Jun-yuan, Chen, Yin-xi, Wang & Jie-dong., Yang 1986. Rare earth and other trace elements in biogenic apatite across the Cambrian–Ordovician boundary. In Aspects of Cambrian–Ordovician Boundary in Dayangcha, China (ed. Jun-yuan, Chen), pp. 61–71. Beijing: China Prospect Publishing House.Google Scholar
Cowie, J. W., Ziegler, W., Boucot, A. J., Bassett, M. G. & Remane, J. 1986. Guidelines and statutes of the International Commission on Stratigraphy (ICS). Courier Forschungsinstitut Senkenberg 83, 1–14.Google Scholar
Derby, J. R., Lane, H. R. & Norford, B. S. 1972. Uppermost Cambrian-basal Ordovician faunal succession in Alberta and correlation with similar sequences in the western United States. Proceedings of the 24th International Geological Congress, Montreal 7, 503–12.Google Scholar
Xi-ping., Dong 1986. Conodont-based Cambrian–Ordovician boundary at Huanghuachang of Yichang, Hubei. In Stratigraphy and Palaeontology of Systemic Boundaries in China: Cambrian–Ordovician Boundary (2) pp. 383–412, pls. I–III. Nanjing: Anhui Science and Technology Publishing House.Google Scholar
Druce, E. C. & Jones, P. J. 1971. Cambro-Ordovician conodonts from the Burke River structural belt, Queensland. Australia Bureau of Mineral Resources, Geology, and Geophysics, Bulletin 110, 158 pp., 20 pls.Google Scholar
Druce, E. C., Shergold, J. H. & Radke, B. M. 1982. A reassessment of the Cambrian–Ordovician boundary section at Black Mountain, western Queensland, Australia. In The Cambrian–Ordovician Boundary: Sections, Fossil Distributions, and Correlations (ed. Bassett, M. G. Dean, W. T.), pp. 193–209. National Museum of Wales, Geological Series No.3.Google Scholar
Dubinina, S. V. 1982. Konodontovye assotsiatsii pogranichnykh otlozheniy kembriya i ordovika Malogo Karatau (Yuzhnyy Kazakhstan) [The conodont associations of the Cambrian–Ordovician boundary sediments in Malyi Karatau (Southern Kazakhstan)] Moscow; Izvestiya Akademii Nauk SSSR, Seriya Geologicheskaya 1982 (4), 47–54.Google Scholar
Erdtmann, B.-D. 1988. The earliest Ordovician nematophorid graptolites: taxonomy and correlation. Geological Magazine 125, 327–48.CrossRefGoogle Scholar
Ethington, R. L. & Clark, D. L. 1971. Lower Ordovician conodonts in North America. In Symposium on Conodont Biostratigraphy (ed. Sweet, W. C. Bergström, S. M.), pp. 63–82, pls. 1, 2. Geological Society of America, Memoir 127.CrossRefGoogle Scholar
Ethington, R. L. & Clark, D. L. 1982. Lower and Middle Ordovician conodonts from the Ibex Area, western Millard County, Utah. Brigham Young University Geology Studies 28 (2), 122 pp., 14 pls.Google Scholar
Fåhraeus, L. E. & Nowlan, G. S. 1978. Franconian (Late Cambrian) to early Champlainian (Middle Ordovician) conodonts from the Cow Head Group, western Newfoundland. Journal of Paleontology 52, 444–71, 3 pls.Google Scholar
Fortey, R., Landing, E. & Skevington, D. 1982. Cambrian–Ordovician boundary sections in the Cow Head Group, western Newfoundland. In The Cambrian-Ordovician Boundary: Sections, Fossil Distributions, and Correlations (ed. Bassett, M. G. Dean, W. T.), pp. 95–129. National Museum of Wales, Geological Series No. 3.Google Scholar
Furnish, W. M. 1938. Conodonts from the Prairie du Chien beds of the Upper Mississippi Valley. Journal of Paleontology 12, 318–40, pl. 41, 42.Google Scholar
Hedberg, H. D. 1976. International Stratigraphic Guide. New York: John Wiley. 200 pp.Google Scholar
Hintze, L. F. 1982. Ibexian Series (Lower Ordovician) type section, western Utah, U.S.A. In The Ordovician System in the United States, Correlation Chart and Explanatory Notes (ed. Ross, R. J. Jr Bergstrom, S. M.), pp. 7–10. International Union of Geological Sciences, Publication 12.Google Scholar
Hintze, L. F., Miller, J. F. & Taylor, M. E. 1980. Upper Cambrian–Lower Ordovician Notch Peak Formation in western Utah. U.S. Geological Survey Open-File Report 80–776, Denver. 67 pp.Google Scholar
Hünicken, M. A., Suarez, R. & Sarmentio, G. N. 1982. Lower Ordovician conodonts from Argentina [abstract]. In Abstracts for IV International Symposium on the Ordovician System (ed. Bruton, D. L. Williams, S. H.), p. 25. University of Oslo Paleontological Contributions No. 280.Google Scholar
James, N. P. & Stevens, R. K. 1986. Stratigraphy and correlation of the Cambro-Ordovician Cow Head Group, western Newfoundland. Geological Survey of Canada Bulletin 366, 143 pp.Google Scholar
Johnson, J. G. 1979. Intent and reality in biostratigraphic zonation. Journal of Paleontology 53, 931–42.Google Scholar
Jones, P. J. 1971. Lower Ordovician conodonts from the Bonaparte Gulf basin and the Daly River basin, northwestern Australia. Australia Bureau of Mineral Resources, Geology and Geophysics, Bulletin 117, 80 pp., 9 pls.Google Scholar
Jones, P. J., Shergold, J. H. & Druce, E. C. 1971. Late Cambrian and Early Ordovician stages in western Queensland. Journal of the Geological Society of Australia 18, 1–32.CrossRefGoogle Scholar
Landing, E. 1982. Conodont biostratigraphy and thermal alteration indices of the upper St Charles and lower Garden City Formations, Bear River Range, northern Utah and southeastern Idaho. Denver: U.S. Geological Survey Open-File Report, 81–720. 29 pp.Google Scholar
Landing, E. 1983. Highgate Gorge: Upper Cambrian and Lower Ordovician continental slope deposition and biostratigraphy. Journal of Paleontology 57, 1149–87.Google Scholar
Landing, E., Barnes, C. R. & Stevens, R. K. 1986. Tempo of earliest Ordovician graptolite faunal succession: conodont-based correlation from the Tremadocian of Quebec. Canadian Journal of Earth Sciences 23, 1928–49.CrossRefGoogle Scholar
Landing, E., Ludvigsen, R. & von Bitter, P. H. 1980. Upper Cambrian to Lower Ordovician conodont biostratigraphy and biofacies, Rabbitkettle Formation, District of Mackenzie. Royal Ontario Museum, Life Sciences Contributions No. 126, Toronto. 42 pp.Google Scholar
Landing, E., Taylor, M. E. & Erdtmann, B.-D. 1978. Correlation of the Cambrian–Ordovician boundary between the Acado-Baltic and North American faunal provinces. Geology 6, 75–8.2.0.CO;2>CrossRefGoogle Scholar
LeMone, D. V. 1975. Correlation aspects of the Ordovician of the southwestern United States. In Exploration from the Mountains to the Basin (ed. Hills, J. M.), pp. 169–90. El Paso, Texas: El Paso Geological Society, 1975 Guidebook.Google Scholar
Yao-kun., Lin 1986. A new planktonic graptolite fauna. In Aspects of Cambrian–Ordovician Boundary in Dayangcha, China (ed. Jun-yuan, Chen), pp. 224–54, pls. 55–66. Beijing: China Prospect Publishing House.Google Scholar
Ludvigsen, R. & Westrop, S. R. 1985. Three new Upper Cambrian stages for North America. Geology 13, 139–43.2.0.CO;2>CrossRefGoogle Scholar
Miller, J. F. 1969. Conodont fauna of the Notch Peak Limestone (Cambro-Ordovician), House Range, Utah. Journal of Paleontology 43, 413–39, pls. 63–6.Google Scholar
Miller, J. F. 1970. Conodont zonation of the uppermost Cambrian and lowest Ordovician [abstract]. Geological Society of America, Abstracts with Programs for 1970 2, 624.Google Scholar
Miller, J. F. 1978. Upper Cambrian and lowest Ordovician conodont faunas of the House Range, Utah. In Upper Cambrian to Middle Ordovician Conodont Faunas of Western Utah (ed. Miller, J. F.), pp. 1–33. Southwest Missouri State University Geoscience Series 5.Google Scholar
Miller, J. F. 1980. Taxonomic revisions of some Upper Cambrian and Lower Ordovician conodont faunas with comments on their evolution. University of Kansas Paleontological Contributions, Paper 99, Lawrence. 44 pp., 2 pls.Google Scholar
Miller, J. F. 1984. Cambrian and earliest Ordovician conodont evolution, biofacies, and provincialism. In Conodont Biofacies and Provincialism (ed. Clark, D. L.), pp. 43–68. Geological Society of America, Special Paper 196.CrossRefGoogle Scholar
Miller, J. F. 1987. Upper Cambrian and basal Ordovician conodont faunas of the southwest flank of the Llano uplift, Texas. In Early and Late Paleozoic Conodont Faunas of the Llano Uplift Region, Central Texas – Biostratigraphy, Systemic Boundary Relationships, and Stratigraphic Importance (ed. Grayson, R. C. Jr), pp. 1–22. Guidebook for Field Trip 1, 1987 Meeting of South-Central Section, Geological Society of America.Google Scholar
Miller, J. F. & Kurtz, V. E. 1979. Reassignment of the Dolomite Point Formation of East Greenland from the Middle Cambrian to the Lower Ordovician based on conodonts [abstract]. Geological Society of America, Abstracts with Programs 11, 480.Google Scholar
Miller, J. F., Robison, R. A. & Clark, D. L. 1974. Correlation of Tremadocian conodont and trilobite faunas, Europe and North America [abstract]. Geological Society of America, Abstracts with Programs 6, 1048–49.Google Scholar
Miller, J. F., Taylor, M. E., Stitt, J. H., Ethington, R. L., Hintze, L. F. & Taylor, J. F. 1982. Potential Cambrian–Ordovician boundary stratotype sections in the western United States. In The Cambrian–Ordovician Boundary: Section, Fossil Distributions, and Correlations (ed. Bassett, M. G. Dean, W. T.), pp. 155–80. National Museum of Wales, Geological Series No. 3.Google Scholar
Müller, K. J. 1959. Kambrische Conodonten. Deutsche Geologische Gesellschaft, Zeitschrift 111, 434–85, pls. 11–15.CrossRefGoogle Scholar
Müller, K. J. 1973. Late Cambrian and Early Ordovician conodonts from northern Iran. Iran Geological Survey, Report 30, 77 pp., 11 pls.Google Scholar
Nogami, Y. 1966. Kambrische Conodonten von China, Teil 1: Conodonten aus den oberkambrischen Kusan–Schichten. Kyoto University College of Science Memoirs, Series B 32, 351–67, pls. 9, 10.Google Scholar
Nogami, Y. 1967. Kambrische Conodonten von China, Teil 2: Conodonten aus den hoch oberkambrischen Yencho-Schichten. Kyoto University College of Science Memoirs, Series B 33, 211–19, 1 pl.Google Scholar
Nowlan, G. S. 1985. Late Cambrian and Early Ordovician conodonts from the Franklinian Geosyncline, Canadian Arctic Islands. Journal of Paleontology 59, 96–122.Google Scholar
Özgül, N. & Gedik, I. 1973. New data on the stratigraphy and the conodont faunas of the Caltepe Limestone and the Seydisehir Formation, lower Paleozoic of central Taurus Range. Geological Society of Turkey Bulletin 16, 39–52, 1 pl.Google Scholar
Pander, C. H. 1856. Monographie der fossilen Fische des silurischen Systems der russisch–baltischen Gouvernements. Königliche Akademie der Wissenschaften, St Petersburg. x + 91 pp., 9 pls.Google Scholar
Yi-yuan., Qian 1986. Trilobites. In Aspects of Cambrian–Ordovician Boundary in Dayangcha, China (ed. Jun-yuan, Chen), pp. 255–313, pls. 67–82. Beijing: China Prospect Publishing House.Google Scholar
Robison, R. A., Rowell, A. J., Fritz, W. H., Kurtz, V. E., Miller, J. F., Norford, B. S., Palmer, A. J., Repetski, J. E., Stitt, J. H., Taylor, J. F. & Taylor, M. E. 1985. Comment [on ‘Three new Upper Cambrian stages for North America’]. Geology 13, 666–7.2.0.CO;2>CrossRefGoogle Scholar
Shaw, A. B. 1964. Time in Stratigraphy. New York: McGraw-Hill, 365 pp.Google Scholar
Shergold, J. H. 1980. Late Cambrian trilobites from the Chatsworth Limestone, western Queensland. Australia Bureau of Mineral Resources, Geology, and Geophysics, Bulletin 186, 181 pp.Google Scholar
Shergold, J. H. 1988. Review of trilobite biofacies distributions at the Cambrian–Ordovician Boundary Geological Magazine 125, 363–80.CrossRefGoogle Scholar
Stitt, J. H. 1977. Late Cambrian and earliest Ordovician trilobites, Wichita Mountains area, Oklahoma. Oklahoma Geological Survey, Bulletin 124, 79 pp., 7 pls.Google Scholar
Taylor, M. E. & Landing, E. 1982. Biostratigraphy of the Cambrian-Ordovician transition in the Bear River Range, Utah and Idaho, western United States. In The Cambrian–Ordovician Boundary: Sections, Fossil Distributions, and Correlations (ed. Bassett, M. G. Dean, W. T.), pp. 181–91. National Museum of Wales, Geological Series No. 3.Google Scholar
Taylor, M. E., Repetski, J. E. & Sprinkle, J. 1981. Paleontology and biostratigraphy of the Whipple Cave Formation and Lower House Limestone, Sawmill Canyon, Egan Range, Nevada. In Cambrian Stratigraphy and Paleontology of the Great Basin and Vicinity, Western United States (ed. Taylor, M. E. Palmer, A. R.), pp. 73–7. Guidebook for Field Trip 1, 2nd International Symposium on the Cambrian System.Google Scholar
Tipnis, R. S., Chatterton, B. D. E. & Ludvigsen, R. 1978. Ordovician conodont biostratigraphy of the southern District of Mackenzie, Canada. In Western and Arctic Canadian Biostratigraphy (ed. Stelk, C. R., Chatterton, B. D. E.), pp. 39–91, pls. 1–9. Geological Association of Canada, Special Paper 18.Google Scholar
Zhi-hao, Wang 1985. Conodonts. In Study on Cambrian-Ordovician Boundary Strata and its Biota in Dayangcha, Hunjiang, Jilin, China, pp. 27–34, 83–101. Beijing: China Prospect Publishing House.Google Scholar
Zhi-hao., Wang 1986. Late Cambrian and Early Ordovician conodonts from North and Northeast China with comments on the Cambrian–Ordovician boundary. In Stratigraphy and Paleontology of Systemic Boundaries in China: Cambrian–Ordovician Boundary (2), pp. 195–258, pls. I–XIV. Nanjing: Nanjing Institute of Geology & Palaeontology, Anhui Science and Technology Publishing House.Google Scholar
Wright, J., Miller, J. F. & Holser, W. T. 1987. Conodont chemostratigraphy across the Cambrian–Ordovician boundary: western United Stated and southeast China. In Conodonts: Investigative Techniques (ed. Austin, R. L.), pp. 256–83. London: Ellis Horwood.Google Scholar
Wright, T. O., Ross, R. J. Jr & Repetski, J. E. 1984. Newly discovered youngest Cambrian or oldest Ordovician fossils from the Robertson Bay terrane (formerly Precambrian), northern Victoria Land, Antarctica. Geology 12, 301–5.2.0.CO;2>CrossRefGoogle Scholar
Jun-ming, Zhao & Jun-yuan., Chen 1986. Lithofacies sequence. In Aspect of Cambrian-Ordovician Boundary in Dayangcha, China (ed. Jun-yuan, Chen), pp. 15–34. Beijing: China Prospect Publishing House.Google Scholar
Da., Zhao 1986. Conodonts. In Cambrian–Ordovician Boundary and its Interval Biotas, Southern Jilin, Northeast China. Journal of Changchun College of Geology, Special Issue of Stratigraphy and Palaeontology, Changchun 87–110, pls. 28–33.Google Scholar