The Cambrian succession of the Tingskullen drill core from northern Öland comprises Cambrian Series 2 and Miaolingian (Wuliuan Stage) siliciclastic strata. The major portion of the succession is represented by the Miaolingian Borgholm Formation, which, in ascending order, is subdivided into the Mossberga, Bårstad and Äleklinta members. The Äleklinta Member is barren of body fossils, whereas the Mossberga and Bårstad members are moderately to highly fossiliferous and biostratigraphically reasonably well constrained. Trilobites and agnostoids from the Bårstad Member are indicative of the Acadoparadoxides pinus Zone. The Mossberga Member has not yielded any zonal guide fossils but is tentatively assigned to the Eccaparadoxides insularis Zone. A δ13Corg curve throughout the Borgholm Formation shows a general positive trend up-section without any distinctive excursion, suggesting that the Wuliuan Acadoparadoxides (Baltoparadoxides) oelandicus Superzone (the ‘Oelandicus beds’) of Öland is younger than the negative Redlichiid–Olenellid Extinction Carbon isotope Excursion (ROECE), which is known from near the top of Stage 4 and close to the traditional ‘Lower–Middle Cambrian boundary’ in several parts of the world.
Ahlberg, P. 1989. Cambrian stratigraphy of the När 1 deep well, Gotland. Geologiska Föreningens i Stockholm Förhandlingar, 111, 137–148.
https://doi.org/10.1080/11035898909453786
Ahlberg, P., Axheimer, N., Babcock, L. E., Eriksson, M. E., Schmitz, B. & Terfelt, F. 2009. Cambrian high-resolution biostratigraphy and carbon isotope chemostratigraphy in Scania, Sweden: first record of the SPICE and DICE excursions in Scandinavia. Lethaia, 42, 2–16.
https://doi.org/10.1111/j.1502-3931.2008.00127.x
Ahlberg, P., Lundberg, F., Erlström, M., Calner, M., Lindskog, A., Dahlqvist, P. & Joachimski, M. M. 2019. Integrated Cambrian biostratigraphy and carbon isotope chemostratigraphy of the Grönhögen-2015 drill core, Öland, Sweden. Geological Magazine, 156, 935–949.
https://doi.org/10.1017/S0016756818000298
Asklund, B. & Thorslund, P. 1935. Fjällkedjerandens bergbyggnad i norra Jämtland och Ångermanland. Sveriges geologiska undersökning, C382, 1–110.
Axheimer, N. & Ahlberg, P. 2003. A core drilling through Cambrian strata at Almbacken, Scania, S. Sweden: trilobites and stratigraphical assessment. GFF, 125, 139–156.
https://doi.org/10.1080/11035890301253139
Babcock, L. E, Peng, S. C., Geyer, G. & Shergold, J. H. 2005. Changing perspectives on Cambrian chronostratigraphy and progress toward subdivision of the Cambrian System. Geoscience Journal, 9, 101–106.
https://doi.org/10.1007/BF02910572
Babcock, L. E., Robison, R. A., Rees, M. N., Peng, S. C. & Saltzman, M. R. 2007. The Global boundary Stratotype Section and Point (GSSP) of the Drumian Stage (Cambrian) in the Drum Mountains, Utah, USA. Episodes, 30, 84–94.
https://doi.org/10.18814/epiiugs/2007/v30i2/003
Babcock, L. E., Peng, S. C., Brett, C. E., Zhu, M. Y., Ahlberg, P., Bevis, M. & Robison, R. A. 2015. Global climate, sea level cycles, and biotic events in the Cambrian Period. Palaeoworld, 24, 5–15.
https://doi.org/10.1016/j.palwor.2015.03.005
Babcock, L. E., Peng, S. C. & Ahlberg, P. 2017. Cambrian trilobite biostratigraphy and its role in developing an integrated history of the Earth system. Lethaia, 50, 381–399.
https://doi.org/10.1111/let.12200
Barili, R., Neilson, J. E., Brasier, A. T., Goldberg, K., Bardola, T. P., de Ros, L. F. & Leng, M. 2018. Carbon isotopes, stratigraphy, and environmental change: the Middle–Upper Cambrian Positive Excursion (SPICE) in Port au Port Group, western Newfoundland, Canada. Canadian Journal of Earth Sciences, 55, 1209–1222.
https://doi.org/10.1139/cjes-2018-0025
Barrande, J. 1852. Système Silurien du Centre de la Bohême. I. Recherches paléontologiques, vol. 1 (Crustacés: Trilobites). Prague, Paris, xx + 935 pp.
https://doi.org/10.5962/bhl.title.14776
Bruton, D. L. & Harper, D. A. T. 2000. A mid-Cambrian shelly fauna from Ritland, western Norway and its palaeogeographical implications. Bulletin of the Geological Society of Denmark, 47, 29–51.
Buchardt, B., Nielsen, A. T. & Schovsbo, N. H. 1997. Alunskiferen i Skandinavien. Geologisk Tidsskrift, 1997(3), 1–30.
Calner, M., Lehnert, O., Wu, R. C., Dahlqvist, P. & Joachimski, M. M. 2014. δ13C chemostratigraphy in the Lower–Middle Ordovician succession of Öland (Sweden) and the global significance of the MDICE. GFF, 136, 48–54.
https://doi.org/10.1080/11035897.2014.901409
Conway Morris, S. & Rushton, A. W. A. 1988. Precambrian to Tremadoc biotas in the Caledonides. In The Caledonian–Appalachian Orogen (Harris, A. L. & Fettes, D. J., eds), Geological Society Special Publication, 38, 93–109.
https://doi.org/10.1144/GSL.SP.1988.038.01.07
Dahlqvist, P., Calner, M., Lehnert, O. & Ahlberg, P. 2013. A complete record of the ‘Lower’ Cambrian–Middle Ordovician succession of Öland, southern Sweden, based on the Tingskullen core. In Proceedings of the 3rd IGCP 591 Annual Meeting – Lund, Sweden, 9–19 June 2013 (Lindskog, A. & Mehlqvist, K., eds), pp. 74–76. Lund University.
Dawson, J. W. 1868. Acadian Geology. Second Edition. MacMillan and Company, London, 694 pp.
Edwards, C. T. & Saltzman, M. R. 2016. Paired carbon isotopic analysis of Ordovician bulk carbonate (δ13Ccarb) and organic matter (δ13Corg) spanning the Great Ordovician Biodiversification Event. Palaeogeography, Palaeoclimatology, Palaeoecology, 458, 102–117.
https://doi.org/10.1016/j.palaeo.2015.08.005
Epstein, A. G., Epstein, J. B. & Harris, L. D. 1977. Conodont color alteration – an index to organic metamorphism. US Geological Survey Professional Paper, 995, 1–27.
https://doi.org/10.3133/pp995
Erlström, M. 2016. Litologisk och geokemisk karaktärisering av berggrundsavsnitt på södra Öland – resultat från kärnborrning vid Grönhögen. SGU-rapport,15, 1–37.
Esteve, J. 2014. Intraspecific variability in paradoxidid trilobites from the Purujosa trilobite assemblage (middle Cambrian, northeast Spain). Acta Palaeontologica Polonica, 59, 215–240.
Faggetter, L. E., Wignall, P. B., Pruss, S. B., Newton, R. J., Sun, Y. & Crowley, S. F. 2017. Trilobite extinctions, facies changes and the ROECE carbon isotope excursion at the Cambrian Series 2–3 boundary, Great Basin, western USA. Palaeogeography, Palaeoclimatology, Palaeoecology, 478, 53–66.
https://doi.org/10.1016/j.palaeo.2017.04.009
Faggetter, L. E., Wignall, P. B., Pruss, S. B., Sun, Y., Raine, R. J., Newton, R. J., Widdowson, M., Joachimski, M. M. & Smith, P. M. 2018. Sequence stratigraphy, chemostratigraphy and facies analysis of Cambrian Series 2 – Series 3 boundary strata in northwestern Scotland. Geological Magazine, 155, 865–877.
https://doi.org/10.1017/S0016756816000947
Fan, R., Deng, S. H. & Zhang, X. L. 2011. Significant carbon isotope excursions in the Cambrian and their implications for global correlations. Science China Earth Sciences, 54, 1686–1694.
https://doi.org/10.1007/s11430-011-4313-z
Fatka, O., Knížek, F. & Kozák, V. 2015. Condylopyge Hawle et Corda, 1847 in the Příbram-Jince Basin (Barrandian area, the Czech Republic, Agnostida). Acta Musei Nationalis Pragae, B71, 103–109.
https://doi.org/10.14446/AMNP.2015.103
Fletcher, T. P., Theokritoff, G., Lord, G. S. & Zeoli, G. 2005. The early paradoxidid harlani trilobite fauna of Massachusetts and its correlatives in Newfoundland, Morocco, and Spain. Journal of Paleontology, 79, 312–336.
https://doi.org/10.1666/0022-3360(2005)079<0312:TEPHTF>2.0.CO;2
Geyer, G. 2019. A comprehensive Cambrian correlation chart. Episodes, 42, 321–332.
https://doi.org/10.18814/epiiugs/2019/019026
Geyer, G. & Corbacho, J. 2015. The Burlingiidae (Trilobita): revised generic composition, stratigraphy, and the first species from the early Middle Cambrian of West Gondwana. GFF, 137, 212–225.
https://doi.org/10.1080/11035897.2015.1027266
Geyer, G. & Shergold, J. 2000. The quest for internationally recognized divisions of Cambrian time. Episodes, 23, 188–195.
https://doi.org/10.18814/epiiugs/2000/v23i3/006
Geyer, G. & Vincent, T. 2015. The Paradoxides puzzle resolved: the appearance of the oldest paradoxidines and its bearing on the Cambrian Series 3 lower boundary. Paläontologische Zeitschrift, 89, 335–398.
https://doi.org/10.1007/s12542-014-0225-5
Hagenfeldt, S. 1994. The Cambrian File Haidar and Borgholm formations in the Central Baltic and south central Sweden. Stockholm Contributions in Geology, 43, 69–110.
Hawle, I. & Corda, A. J. C. 1847. Prodrom einer Monographie der böhmischen Trilobiten. Abhandlungen der Königlichen Böhmischen Gesellschaft der Wissenschaften, Prague, 5(5), 117−292.
Henderson, M. A., Serra, F., Feltes, N. A., Albanesi, G. L. & Kah, L. C. 2018. Paired isotope records of carbonate and organic matter from the Middle Ordovician of Argentina: intrabasinal variation and effects of the marine chemocline. Palaeogeography, Palaeoclimatology, Palaeoecology, 458, 107–130.
https://doi.org/10.1016/j.palaeo.2017.10.018
Henningsmoen, G. 1952. Early middle Cambrian fauna from Rogaland, SW Norway (Paradoxides oelandicus stage = 1c α). Norsk Geologisk Tidsskrift, 30, 13–31.
Hessland, I. 1955. Studies in the lihogenesis of the Cambrian and basal Ordovician of the Böda Hamn sequence of strata. Bulletin of the Geological Institution of the University of Upsala, 35, 35–109.
Holm, G. 1893. Sveriges kambrisk-siluriska Hyolithidæ och Conulariidæ. Sveriges geologiska undersökning, C112, 1–172.
Jaanusson, V. 1960. The Viruan (Middle Ordovician) of Öland. Bulletin of the Geological Institutions of the University of Uppsala, 38, 207–288.
Jaanusson, V. 1976. Faunal dynamics in the Middle Ordovician (Viruan) of Baltocandia. In The Ordovician System: Proceedings of a Palaeontological Association Symposium, Birmingham, September 1974 (Bassett, M. G., ed.), pp. 301–326. University of Wales Press and National Museum of Wales, Cardiff.
Jaanusson, V. 1979. Ordovician. In Treatise on Invertebrate Paleontology. Part A. Introduction (Robison, R. A. & Teichert, C., eds), pp. A136–A166. Geological Society of America and University of Kansas, Boulder, Colorado and Lawrence, Kansas.
Jaanusson, V. 1995. Confacies differentiation and upper Middle Ordovician correlation in the Baltoscandian basin. Proceedings of the Estonian Academy of Sciences, Geology, 44, 73–86.
Jaekel, O. 1909. Über die Agnostiden. Zeitschrift der Deutschen Geologischen Gesellschaft, 61, 380–401.
Kobayashi, T. 1939. On the agnostids (Part 1). Journal of the Faculty of Science, Imperial University of Tokyo, Section II, 5(5), 69–198.
Landing, E., Peng, S. C., Babcock, L. E., Geyer, G. & Moczydłowska-Vidal, M. 2007. Global standard names for the lowermost Cambrian Series and Stage. Episodes, 30, 287–289.
https://doi.org/10.18814/epiiugs/2007/v30i4/004
Lin, J.-P., Sundberg, F. A., Jiang, G., Montañez, I. P. & Wotte, T. 2019. Chemostratigraphic correlations across the first major trilobite extinction and faunal turnovers between Laurentia and South China. Scientific Reports, 9:17392, 1–15.
https://doi.org/10.1038/s41598-019-53685-2
Lindskog, A. & Eriksson, M. E. 2017. Megascopic processes reflected in the microscopic realm: sedimentary and biotic dynamics of the Middle Ordovician “orthoceratite limestone” at Kinnekulle, Sweden. GFF, 139, 163–183.
https://doi.org/10.1080/11035897.2017.1291538
Lindskog, A. & Young, S. A. 2019. Dating of sedimentary rock intervals using visual comparison of carbon isotope records: a comment on the recent paper by Bergström et al. concerning the age of the Winneshiek Shale. Lethaia, 52, 299–303.
https://doi.org/10.1111/let.12316
Linnarsson, J. G. O. 1869. Om Vestergötlands cambriska och siluriska aflagringar. Kongliga Svenska Vetenskaps-Akademiens Handlingar, 8(2), 1–89.
Linnarsson, G. 1876a. Geologiska iakttagelser under en resa på Öland. Geologiska Föreningens i Stockholm Förhandlingar, 3, 71–86.
https://doi.org/10.1080/11035897609448163
Linnarsson, G. 1876b. On the Brachiopoda of the Paradoxides Beds of Sweden. Bihang till Kongliga Svenska Vetenskaps-Akademiens Handlingar, 3, 1–34.
https://doi.org/10.5962/bhl.part.4014
Linnarsson, G. 1877. Om faunan i lagren med Paradoxides ölandicus. Geologiska Föreningens i Stockholm Förhandlingar, 3, 352–375.
https://doi.org/10.1080/11035897709446406
Malinky, J. M. & Berg-Madsen, V. 1999. A revision of Holm’s Early and early Mid Cambrian hyoliths of Sweden. Palaeontology, 42, 25–65.
https://doi.org/10.1111/1475-4983.00061
Martinsson, A. 1965. Aspects of a Middle Cambrian thanatotope on Öland. Geologiska Föreningens i Stockholm Förhandlingar, 87, 181–230.
https://doi.org/10.1080/11035896509448903
Martinsson, A. 1974. The Cambrian of Norden. In Lower Palaeozoic Rocks of the World. 2. Cambrian of the British Isles, Norden, and Spitsbergen (Holland, C. H., ed.), pp. 185–283. John Wiley & Sons, London.
Matthew, G. F. 1887. Illustrations of the fauna of the St. John Group. No. 4. – On the smaller-eyed trilobites of Division I., with a few remarks on the species of the higher divisions of the group. Canadian Record of Science, 2, 357–363.
Naimark, E. B. & Pegel, T. 2017. Revision of the Cambrian Agnostina (Trilobita?) from Russia. Paleontological Journal, 51, 1167–1248.
https://doi.org/10.1134/S0031030117110016
Nielsen, A. T. & Ahlberg, P. 2019. The Miaolingian, a new name for the ‘Middle’ Cambrian (Cambrian Series 3): identification of lower and upper boundaries in Baltoscandia. GFF, 141, 162–173.
https://doi.org/10.1080/11035897.2019.1621374
Nielsen, A. T. & Schovsbo, N. H. 2007. Cambrian to basal Ordovician lithostratigraphy in southern Scandinavia. Bulletin of the Geological Society of Denmark, 53, 47–92.
Nielsen, A. T. & Schovsbo, N. H. 2011. The Lower Cambrian of Scandinavia: Depositional environment, sequence stratigraphy and palaeogeography. Earth-Science Reviews, 107, 207–310.
https://doi.org/10.1016/j.earscirev.2010.12.004
Nielsen, A. T. & Schovsbo, N. H. 2015. The regressive Early-Mid Cambrian ‘Hawke Bay Event’ in Baltoscandia: Epeirogenic uplift in concert with eustasy. Earth-Science Reviews, 151, 288–350.
https://doi.org/10.1016/j.earscirev.2015.09.012
Nielsen, A. T., Weidner, T., Terfelt, F. & Høyberget, M. 2014. Upper Cambrian (Furongian) biostratigraphy in Scandinavia revisited: definition of superzones. GFF, 136, 193–197.
https://doi.org/10.1080/11035897.2013.878748
Nowicki, J. & Żylińska, A. 2019. The first occurrence of the earliest species of Acadoparadoxides outside West Gondwana (Cambrian; Holy Cross Mountains, Poland). Geological Magazine, 156, 1027–1051.
https://doi.org/10.1017/S0016756818000341
Peng, S. C., Babcock, L. E., Robison, R. A., Lin, H. L., Rees, M. N. & Saltzman, M. R. 2004. Global Standard Stratotype-section and Point (GSSP) of the Furongian Series and Paibian Stage (Cambrian). Lethaia, 37, 365–379.
https://doi.org/10.1080/00241160410002081
Peng, S. C., Babcock, L. E., Zuo, J. X., Lin, H. L., Zhu, X. J., Yang, X. F., Robison, R. A., Qi, Y. P., Bagnoli, G. & Chen, Y. 2009. The Global boundary Stratotype Section and Point (GSSP) of the Guzhangian Stage (Cambrian) in the Wuling Mountains, northwestern Hunan, China. Episodes, 32, 41–55.
https://doi.org/10.18814/epiiugs/2009/v32i1/006
Peng, S., Babcock, L. E. & Cooper, R. A. 2012. The Cambrian Period. In The Geologic Time Scale 2012 (Gradstein, F. M., Ogg, J. G., Schmitz, M. D. & Ogg, G. M., eds), pp. 437–488. Elsevier, Oxford.
https://doi.org/10.1016/B978-0-444-59425-9.00019-6
Raymond, P. E. 1913. Some changes in the names of genera of trilobites. The Ottawa Naturalist, 26, 137–142.
Robison, R. A. 1982. Some Middle Cambrian agnostoid trilobites from western North America. Journal of Paleontology, 56, 132–160.
Robison, R. A. 1995. Revision of the Middle Cambrian trilobite Agnostus acadicus Hartt. Journal of Paleontology, 69, 302–307.
https://doi.org/10.1017/S0022336000034636
Robison, R. A., Rosova, A. V., Rowell, A. J. & Fletcher, T. P. 1977. Cambrian boundaries and divisions. Lethaia, 10, 257–262.
https://doi.org/10.1111/j.1502-3931.1977.tb00619.x
Rushton, A. W. A. 1966. The Cambrian trilobites from the Purley Shales of Warwickshire. Monographs of the Palaeontographical Society, 120, 1–55.
Rushton, A. W. A. & Weidner, T. 2007. The Middle Cambrian paradoxidid trilobite Hydrocephalus from Jämtland, central Sweden. Acta Geologica Polonica, 57, 391–401.
Salvador, A. (ed.). 1994. International Stratigraphic Guide. 2nd Ed. International Union of Geological Sciences and the Geological Society of America, Trondheim, 214 pp.
Saltzman, M. R., Young, S. A., Kump, L. R., Gill, B. C., Lyons, T. W. & Runnegar, B. 2011. A pulse of atmospheric oxygen during the late Cambrian. National Academy of Sciences Proceedings, 108, 3876–3881.
https://doi.org/10.1073/pnas.1011836108
Sars, M. 1835. Über einige neue oder unvollständig bekannte Trilobiten. Oken Isis (or Encyclopedische Zeitung), 1835, 333–343.
Schiffbauer, J. D., Huntley, J. W., Fike, D. A., Jeffrey, M. J., Gregg, J. M. & Shelton, K. L. 2017. Decoupling biogeochemical records, extinction, and environmental change during the Cambrian SPICE event. Science Advances, 3(3), e1602158.
https://doi.org/10.1126/sciadv.1602158
Schovsbo, N. H. 2001. Why barren intervals? A taphonomic case study of the Scandinavian Alum Shale and its faunas. Lethaia, 34, 271–285.
https://doi.org/10.1080/002411601753293024
Sjögren, A. 1871. Bidrag till Ölands geologi. Öfversigt af Kongliga Vetenskaps-Akademiens Förhandlingar, 1871(6), 673–681.
Sjögren, A. 1872. Om några försteningar i Ölands kambriska lager. Geologiska Föreningens i Stockholm Förhandlingar, 1, 67–80.
https://doi.org/10.1080/11035897209443816
Šnajdr, M. 1957. O nových trilobitech z českého kambria. Věstnik Ústrědního Ústavu Geologického, 32, 235–244.
https://doi.org/10.3109/10520295709111629
Stouge, S. 2004. Ordovician siliciclastics and carbonates of Öland, Sweden. In International Symposium on Early Palaeozoic Palaeogeography and Palaeoclimate, September 1–3, 2004, Erlangen, Germany (Munnecke, A., Servais, T. & Schulbert, C., eds), Erlanger geologische Abhandlungen – Sonderband, 5, 91–111.
Sundberg, F. A., Karlstrom, K. E., Geyer, G., Foster, J. R., Hagadorn, J. W., Mohr, M. T., Schmitz, M. D., Dehler, C. M. & Crossey, L. J. 2020. Asynchronous trilobite extinctions at the early to middle Cambrian transition. Geology, 48, 441–445.
https://doi.org/10.1130/G46913.1
Terfelt, F., Eriksson, M. E. & Schmitz, B. 2014. The Cambrian–Ordovician transition in dysoxic facies in Baltica – diverse faunas and carbon isotope anomalies. Palaeogeography, Palaeoclimatology, Palaeoecology, 394, 59–73.
https://doi.org/10.1016/j.palaeo.2013.11.021
Tjernvik, T. 1956. On the early Ordovician of Sweden. Stratigraphy and fauna. Bulletin of the Geological Institutions of the University of Uppsala, 36, 107–284.
Wærn, B. 1952. Palaeontology and stratigraphy of the Cambrian and lowermost Ordovician of the Bödahamn core. Bulletin of the Geological Institution of the University of Upsala, 34, 223–250.
Walcott, C. D. 1908. Cambrian Geology and Paleontology, pt. 3 – Cambrian Brachiopoda, descriptions of new genera and species. Smithsonian Miscellaneous Collections, 53, 53–137.
Weidner, T. & Ebbestad, J. O. R. 2014. The early middle Cambrian agnostid Pentagnostus praecurrens (Westergård 1936) from Sweden. Memoirs of the Association of Australasian Palaeontologists, 45, 403–419.
Weidner, T. & Nielsen, A. T. 2009. The Middle Cambrian Paradoxides paradoxissimus Superzone on Öland, Sweden. GFF, 131, 253–268.
https://doi.org/10.1080/11035890903189827
Weidner, T. & Nielsen, A. T. 2014. A highly diverse trilobite fauna with Avalonian affinities from the Middle Cambrian Acidusus atavus Zone (Drumian Stage) of Bornholm, Denmark. Journal of Systematic Palaeontology, 12, 23–92.
https://doi.org/10.1080/14772019.2012.740080
Weidner, T., Rushton, A. W. A. & Ebbestad, J. O. R. 2014. A paradoxidid–agnostoid fauna from the mid-Cambrian (Stage 5) of the Caledonian Lower Allochthon on Tåsjöberget, Ångermanland, Sweden. GFF, 136, 513–530.
https://doi.org/10.1080/11035897.2014.888471
Westergård, A. H. 1922. Sveriges olenidskiffer. Sveriges geologiska undersökning, Ca18, 1–205.
Westergård, A. H. 1929. A deep boring through Middle and Lower Cambrian strata at Borgholm, Isle of Öland. Sveriges geologiska undersökning, C355, 1–19.
Westergård, A. H. 1936. Paradoxides œlandicus beds of Öland with the account of a diamond boring through the Cambrian at Mossberga. Sveriges geologiska undersökning, C394, 1–66.
Westergård, A. H. 1944. Borrningar genom alunskifferlagret på Öland och i Östergötland 1943. Sveriges geologiska undersökning, C463, 1–22.
Westergård, A. H. 1946. Agnostidea of the Middle Cambrian of Sweden. Sveriges geologiska undersökning, C477, 1–140.
Westergård, A. H. 1947. Nya data rörande alunskifferlagret på Öland. Sveriges geologiska undersökning, C483, 1–12.
Westergård, A. H. 1950. Non-agnostidean trilobites of the Middle Cambrian of Sweden. II. Sveriges geologiska undersökning, C511, 1–57.
Westergård, A. H. 1953. Non-agnostidean trilobites of the Middle Cambrian of Sweden. III. Sveriges geologiska undersökning, C526, 1–59.
Woods, M. A., Wilby, P. R., Leng, M. J., Rushton, A. W. A. & Williams, M. 2011. The Furongian (late Cambrian) Steptoean Positive Carbon Isotope Excursion (SPICE) in Avalonia. Journal of the Geological Society, London, 168, 851–861.
https://doi.org/10.1144/0016-76492010-111
Wotte, T., Strauss, H. & Sundberg, F. A. 2011. Carbon and sulfur isotopes from the Cambrian Series 2–Cambrian Series 3 of Laurentia and Siberia. Museum of Northern Arizona Bulletin, 67, 43–63.
Wu, R. C., Calner, M. & Lehnert, O. 2017. Integrated conodont biostratigraphy and carbon isotope chemostratigraphy in the Lower–Middle Ordovician of southern Sweden reveals a complete record of the MDICE. Geological Magazine, 154, 334–353.
https://doi.org/10.1017/S0016756816000017
Zenker, J. 1833. Beiträge zur Naturgeschichte der Urwelt. Organische Reste (Petrefacten) aus der Altenburger Braunkohlen-Formation, dem Blankenburger Quadersandstein, jenaischen bunten Sandstein und böhmischen Uebergangsbirge, mit 6 illuminirten Kupfertafeln. Mauke, Jena, 67 pp.
Zhao, Y. L., Peng, J., Yuan, J. L., Guo, Q. J., Tai, T. S., Yin, L. M., Parsley, L. R., Yang, Y. N., Yang, X. L. & Zhang, P. X. 2012. Stop 5: The Kaili Formation and Kaili Biota at the Wuliu-Zengjiayan section of Guizhou Province, China and proposed Global Standard Stratotype-section and Point (GSSP) of the unnamed Cambrian Series 3, Stage 5. Journal of Guizhou University (Natural Sciences), 29 (Supplement 1), 108–124.
Zhao, Y. L., Yuan, J. L., Babcock, L. E., Guo, Q. J., Peng, J., Yin, L. M., Yang, X. L., Peng, S. C., Wang, C. J., Gaines, R. R., Esteve, J., Tai, T. S., Yang, R. D., Wang, Y., Sun, H. J. & Yang, Y. N. 2019. Global Standard Stratotype-Section and Point (GSSP) for the conterminous base of the Miaolingian Series and Wuliuan Stage (Cambrian) at Balang, Jianhe, Guizhou, China. Episodes, 42, 165–184.
https://doi.org/10.18814/epiiugs/2019/019013
Zhu, M. Y., Babcock, L. E. & Peng, S. C. 2006. Advances in Cambrian stratigraphy and paleontology: integrating correlation techniques, paleobiology, taphonomy and paleoenvironmental reconstruction. Palaeoworld, 15, 217–222.
https://doi.org/10.1016/j.palwor.2006.10.016
Zhu, M. Y., Yang, A. H., Yuan, J. L., Li, G. X., Zhang, J. M., Zhao, F. C., Ahn, S. Y. & Miao, L. Y. 2019. Cambrian integrative stratigraphy and timescale of China. Science China Earth Sciences, 62, 25–60.
https://doi.org/10.1007/s11430-017-9291-0
Żylińska, A. & Masiak, M. 2007. Cambrian trilobites from Brzechów, Holy Cross Mountains (Poland) and their significance in stratigraphic correlation and biogeographic reconstructions. Geological Magazine, 144, 661–686.
https://doi.org/10.1017/S0016756807003366
