Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-26T20:31:03.244Z Has data issue: false hasContentIssue false

Tremadocian (Lower Ordovician) sea-level changes and biotas on the Avalon microcontinent

Published online by Cambridge University Press:  14 July 2015

ED Landing
Affiliation:
1New York State Museum, 222 Madison Avenue, Albany, NY 12230, USA,
Richard A. Fortey
Affiliation:
2Department of Palaeontology, Natural History Museum, Cromwell Road, London SW7 5BD, U.K.

Abstract

The Chesley Drive Group, an Upper Cambrian-Lower Ordovician mudstone-dominated unit, is part of the Ediacaran–Ordovician cover sequence on the North American part of the Avalon microcontinent. The upper Chesley Drive Group on McLeod Brook, Cape Breton Island (previously “McLeod Brook Formation”), has two lithofacies-specific Tremadocian biotas. An older low-diversity benthic assemblage (shallow burrowers, Bathysiphon, phosphatic brachiopods, asaphid trilobites) is in lower upper Tremadocian green-gray mudstone. This wave-influenced, slightly dysoxic facies has Bathysiphon–brachiopod shell lags in ripple troughs. The upper fauna (ca. 483 +/- 1 Ma) is in dysoxic-anoxic (d-a), unburrowed, dark gray-black, upper upper (but not uppermost) Tremadocian mudstone with a “mass kill” of the olenid Peltocare rotundifrons (Matthew)—a provincial trilobite in Avalonian North America that likely tolerated low oxygen bottom waters. Scandodus avalonensis Landing n. sp. and Lagenochitina aff. conifundus (Poumot), probable nektic elements and the first upper Tremadocian conodont and chitinozoan reported from Avalon, occur in diagenetic calcareous nodules in the dark gray-black mudstone. An upper Tremadocian transition from lower greenish to upper black mudstone is not exposed on McLeod Brook, but is comparable to a coeval green-black mudstone transition in Avalonian England. The successions suggest that late late Tremadocian (probable Baltic Hunnebergian Age) sea level was higher in Avalon than is suggested from successions on other paleocontinents. The Tremadocian sea-level history of Avalon was a shoaling-deepening-shoaling sequence from d-a black mudstone (lower Tremadocian), to dysoxic green mudstone (lower upper Tremadocian), and back to black mudstone (upper upper Tremadocian).

Scandodus Lindström is emended, with the early species S. avalonensis Landing n. sp. assigned to the emended Family Protopanderodontidae. Triangulodus Van Wamel is considered a junior synonym of Scandodus. Peltocare rotundifrons is emended on the basis of complete specimens.

Type
Research Article
Copyright
Copyright © The Paleontological Society 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Albanese, G. L. and Aceñolaza, G. F. 2005. Conodontes de la Formación Rupasca (Ordovícico Inferior) en la Angosto de Chucalezna, Cordillera Oriental de Jujuy: neuvos elementos bioestratigraphicos para una localidad clásica del noroeste argentine. Ameghiniana, 42:330349.Google Scholar
Alcock, F. J. 1938. Geology of Saint John region, New Brunswick. Geological Survey of Canada, Memoir 216, 65 p.Google Scholar
Barr, S. M. and Raeside, R. P. 1986. Pre-Carboniferous tectonostratigraphic subdivisions of Cape Breton Island, Nova Scotia. Maritime Sediments and Atlantic Geology, 22:252263.Google Scholar
Barr, S. M. and White, C. E. 1996. Contrasts in late Precambrian–Early Paleozoic tectonothermal history between Avalon composite terrane sensu strictu and other possible peri-Gondwanan terranes in southern New Brunswick and Cape Breton Island, Canada, p. 95108. In Nance, R. D. and Thompson, M. D. (eds.), Avalonian and Related Peri-Gondwanan Terranes of the Circum-North Atlantic. Geological Society of America, Special Paper 304, 390 p.CrossRefGoogle Scholar
Barr, S. M., White, C. E., and MacDonald, A. S. 1992. Revision of upper Precambrian–Cambrian stratigraphy, southeastern Cape Breton Island. Geological Survey of Canada, Current Research, Part D, Paper 92-1D:2126.Google Scholar
Bassler, R. S. 1925. Classification and stratigraphic use of the conodonts. Geological Society of America Bulletin, 36:218220.Google Scholar
Bell, W. A. and Gorenson, E. A. 1938. Sydney Sheet, West Half. Geological Survey of Canada, Map. 360A.Google Scholar
Bergström, S. M. 1988. On Pander's Ordovician conodonts: distribution and significance of the Prioniodus elegans fauna in Baltoscandia. Senckenbergiana lethaea, 69:217251.Google Scholar
Brett, C. E., Speyer, S. E., and Baird, G. C. 1986. Storm-generated sedimentary units: tempestite proximality and event stratification in the Middle Devonian Hamilton Group of New York, p. 129156. In Brett, C. E. (ed.), Dynamic Stratigraphy and Depositional Environments of the Hamilton Group (Middle Devonian) in New York State, Part I. New York State Museum Bulletin 457, 156 p.Google Scholar
Bulman, O. M. B. and Rushton, A. W. A. 1973. Tremadoc faunas in central England. Bulletin of the Geological Survey of Great Britain, 43:140.Google Scholar
Burmeister, H. 1843. Die organization der Trilobiten. Berlin, 147 p.Google Scholar
Callaway, C. 1877. On a new area of Upper Cambrian rocks in south Shropshire, with a description of a new fauna. Quarterly Journal of the Geological Society of London, 33:652672.Google Scholar
Clark, D. L., Sweet, W. C., Bergström, S. M., Klapper, G., Austin, R. L., Rhodes, F. H. T., Müller, K. J., Ziegler, W., Lindström, M., Miller, J. F., and Harris, A. J. 1981. Treatise on Invertebrate Paleontology, Part W., Miscellanea, Supplement 2, Conodonta. Geological Society of America and University of Kansas, 202 p.Google Scholar
Dallmeyer, R. D., Doig, R., Nance, R. D., and Murphy, J. B. 1990. 40Ar/ 39Ar and U-Pb mineral ages from the Brookville Gneiss and Green Head Group: implications for terrane analysis and evolution of Avalonian “basement” in southern New Brunswick. Atlantic Geology, 26:247257.Google Scholar
de la Puente, G. S. and Rubenstein, C. V. 2007. The Ordovician chitinozoans from the western Gondwana margin, northwestern Argentina, p. 99105. In Díaz-Martínez, E. and Rábano, I. (eds.), 4th European Meeting on the Palaeontology and Stratigraphy of Latin America. Cuadernos del Museo Geominero, No. 8, Instituto Géologico y Minero de España, 2007.Google Scholar
de la Puente, G. S. and Rubenstein, C. V. 2009. Tremadocian chitinozoans and acritarchs from northwestern Argentina (western Gondwana). Reviews of Palaeobotany and Palynology, 154:6578.Google Scholar
Dean, W. T. and Martin, F. 1978. Lower Ordovician acritarchs and trilobites from Bell Island, eastern Newfoundland. Geological Survey of Canada Bulletin, 284, 35 p.Google Scholar
Drygant, D. M. 1974. Prostyle konodonty Silura i Nizov Devona Volyno-Podolya. Paleontologishe Siborny Lvov Universitaet, 10:6470.Google Scholar
Eichenberg, W. 1930. Conodonten aus dem Kulm des Harzes. Paläontologisches Zeitschrift, 12:177182.CrossRefGoogle Scholar
Fortey, R. A. 1990. Ontogeny, hypostome attachment and trilobite classification. Palaeontology, 33:529576.Google Scholar
Fortey, R. A. 2000. Olenid trilobites: the oldest known chemoautotrophic symbionts? PNAS, 97:65746578.Google Scholar
Fortey, R. A., and Owens, R. M. 1991. A trilobite fauna from the highest Shineton Shales in Shropshire, and the correlation of the latest Tremadoc. Geological Magazine, 128:437464.Google Scholar
Fortey, R. A., and Owens, R. M. 1992. The Habberley Formation: youngest Tremadoc in the Welsh Borderlands. Geological Magazine, 129:553566.Google Scholar
Fortey, R. A., Harper, D. A. T., Ingham, J. K., Owen, A. W., Parkes, M. A., Rushton, A. W. A., and Woodcock, N. H. 2000. A revised correlation of Ordovician rocks of the British Isles. Geological Society of London, Special Report No. 24, 83 p.Google Scholar
Furnish, W. M. 1938. Conodonts from the Prairie du Chien (Lower Ordovician) beds of the upper Mississippi valley. Journal of Paleontology, 12:318340.Google Scholar
Geyer, G., Elicki, O., Fatka, O., and Żylińska, A. 2008. Cambrian, p. 155202. In McCann, T. (ed.), The Geology of Central Europe. Vol. 1: Precambrian and Palaeozoic. Geological Soociety of London.Google Scholar
Gooday, A. J., Pond, D. W., and Bowser, B. S. 2002. Ecology and nutrition of the large agglutinated foraminiferan Bathysiphon capillare in the bathyal NE Atlantic: distribution within the sediment profile and lipid biomarker composition. Marine Ecology, Progress Series, 245:6982.Google Scholar
Harrington, H. J. and Leanza, A. 1957. Ordovician trilobites of Argentina. Special Publications of the Department of Geology, University of Kansas, 1, 276 p.Google Scholar
Harris, R. W. and Harris, B. 1965. Some West Spring Creek (Ordovician, Arbuckle) conodonts from Oklahoma. Oklahoma Geology Notes, 25:3447.Google Scholar
Hawle, I. and Corda, A. J. C. 1847. Prodrom einer Monographie der böhemischen Trilobiten. Abhandlungen kongligischen böhemischen Gesellschaft der Wissenschaften, 5:1176.Google Scholar
Hayes, A. O. 1948. Geology of the area between Bonavista and Trinity Bays, eastern Newfoundland. Geological Survey of Newfoundland Bulletin 32, 56 p.Google Scholar
Hayes, A. O. and Howell, B. J. 1937. Geology of Saint John, New Brunswick. Geological Society of America Special Papers, Number 5, 146 p.Google Scholar
Henningsmoen, G. 1957. The trilobite family Olenidae. Skrifter Utgitt av det Norske-Videnskaps-Akademie i Oslo. Matematisk-naturvidenskapelig Klasse 1, 303 p.Google Scholar
Henningsmoen, G. 1959. Rare Tremadocian trilobites from Norway. Norsk Geologisk Tiddskrift, 39:153174.Google Scholar
Henningsmoen, G. 1975. Moulting in trilobites, p. 179200. In Martinsson, A. (ed.), Evolution and Morphology of the Trilobita, Trilobitoidea and Merostomata. Fossils and Strata 4, 467 p.Google Scholar
Hutchinson, R. D. 1952. The stratigraphy and trilobite faunas of the Cambrian sedimentary rocks of Cape Breton Island, Nova Scotia. Geologial Survey of Canada, Memoir 263, 124 p.Google Scholar
Hutchinson, R. D. 1962. Cambrian stratigraphy and trilobite faunas of southeastern Newfoundland. Geological Survey of Canada, Bulletin 88, 156 p.Google Scholar
Jenness, S. E. 1963. Terra Nova and Bonavista Map-Areas, Newfoundland (2 D E1/2 and 2C). Geological Survey of Canada Memoir 327, 184 p.Google Scholar
Ji, Z., and Barnes, C. R. 1994. Lower Ordovician conodonts of the St. George Group, Port au Port Peninsula, western Newfoundland, Canada. Palaeontographica Canadiana 11, 149 p.Google Scholar
Johnson, K. A., Culver, S. J., and Kamola, D. L. 2005. Marginal marine Foraminifera of the Blackhawk Formation (Late Cretaceous, Utah). Journal of Foraminiferal Research, 35:5064.Google Scholar
Keppie, J. D. and Smith, P. K. 1978. Compilation of isotopic age data of Nova Scotia. Nova Scotia Department of Mines Report 78-4, 21 p.Google Scholar
Keppie, J. D., Nance, R. D., Murphy, J. B., and Dostal, J. 2003. Tethyan, Mediterranean, and Pacific analogues for the Neoproterozoic-Paleozoic birth and development of peri-Gondwana terrances and their transfer to Laurentia and Laurussia. Tectonophysics, 365:195219.Google Scholar
Kesling, R. V. and Chilman, R. B. 1975. Strata and megafossils of the Middle Devonian Silica Formation. University of Michigan Museum of Paleontology, Papers on Paleontology, 8, 408 p.Google Scholar
Klapper, G., Lindström, M., Sweet, W. C., and Zeigler, W. 1977. Catalogue of Conodonts, Vol. III. E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart.Google Scholar
Landing, E. 1980. Late Cambrian-Early Ordovician macrofaunas and phosphatic microfaunas, St. John Group, New Brunswick. Journal of Paleontology, 54:752761.Google Scholar
Landing, E. 1984. Skeleton of lapworthellids and the suprageneric classification of tommotiids (Early and Middle Cambrian phosphatic problematica). Journal of Paleontology, 58:13801398.Google Scholar
Landing, E. 1991. Upper Precambrian through Lower Cambrian of Cape Breton Island: faunas, paleoenvironments, and stratigraphic revision. Journal of Paleontology, 65:570595.Google Scholar
Landing, E. 1996. Avalon—Insular continent by the latest Precambrian, p. 2764. In Nance, R. D. and Thompson, M. (eds.), Avalonian and Related Peri-Gondwanan Terranes of the Circum-North Atlantic. Geological Society of America, Special Paper 304, 390 p.Google Scholar
Landing, E. 2004. Precambrian–Cambrian boundary interval deposition and the marginal platform of the Avalon microcontinent. Journal of Geodynamics, 37:411435.Google Scholar
Landing, E. 2005. Early Paleozoic Avalon-Gondwana unity: an obituary—response to “Palaeontological evidence bearing on global Ordovician-Silurian continental reconstructions” by R. A. Fortey and L. R. M. Cocks. Earth-Science Reviews, 69:169175.Google Scholar
Landing, E. 2007. East Laurentia 2007—a pre-meeting statement, p. 3, 4. In Landing, E. (ed), Ediacaran-Ordovician of East Laurentia—S. W. Ford Memorial Volume. New York State Museum Bulletin 510, 93 p.Google Scholar
Landing, E. and Murphy, J. B. 1991. Uppermost Precambrian(?)–Lower Cambrian of mainland Nova Scotia: faunas, depositional environment, and stratigraphic revision. Journal of Paleontology, 65:382396.Google Scholar
Landing, E. and Westrop, S. R. 1998. Cambrian faunal sequence and depositional history of Avalonian Newfoundland and New Brunswick: Field workshop, p. 575. In Landing, E. and Westrop, S. R. (eds.), Avalon 1997—The Cambrian Standard. Third International Field Conference of the Cambrian Chronostratigraphy Working Group and I.G.C.P. Project 366 (Ecological Aspects of the Cambrian Radiation). New York State Museum Bulletin 492, 92 p.Google Scholar
Landing, E. and Westrop, S. R. 2006. Early Ordovician faunas, stratigraphy, and sea-level history of the middle Beekmantown Group, northeastern New York. Journal of Paleontology, 80:958980.Google Scholar
Landing, E., Taylor, M. E., and Erdtmann, B.-D. 1978. Correlation of the Cambrian–Ordovician boundary between the Acado-Baltic and North American faunal provinces. Geology, 6:7578.Google Scholar
Landing, E., Westrop, S. R., and Knox, L. 1996. Conodonts, stratigraphy, and relative sea-level changes of the Tribes Hill Formation (Lower Ordovician), east-central New York. Journal of Paleontology, 70:652676.Google Scholar
Landing, E., Bowring, S. A., Fortey, R. A., and Davidek, K. L. 1997. U-Pb zircon date from Avalonian Cape Breton Island and geochronologic calibration of the Early Ordovician. Canadian Journal of Earth Sciences, 34:724730.Google Scholar
Landing, E., Westrop, S. R., and Kim, D. H. 2003. First Middle Ordovician biota from southern New Brunswick: stratigraphic and tectonic implications for the evolution of the Avalon continent. Canadian Journal of Earth Sciences, 40:715730.Google Scholar
Landing, E., Westrop, S. R., and Keppie, J. D. 2007. Terminal Cambrian and lowest Ordovician succession of Mexican West Gondwana—biotas and sequence stratigraphy of the Tiñu Formation. Geological Magazine, 144:909936.Google Scholar
Landing, E., Adrain, J. M., Westrop, S. R., and Kröger, B. J. In press. Tribes Hill-Rochdale formations in east Laurentia: proxies for Early Ordovician (Tremadocian) eustasy on a tropical passive margin (New York and west Vermont). Geological Magazine.Google Scholar
Lindholm, K. 1991. Ordovician graptolites in the early Hunneberg of southern Sweden. Palaeontology, 34:283328.Google Scholar
Lindström, M. 1955. Conodonts from the lowermost Ordovician strata of south-central Sweden. Geologiska Föreningens i Stockholm Forhandlingar, 76:517603.Google Scholar
Lindström, M. 1964. Conodonts. Elsevier Publishing Company, New York.Google Scholar
Lindström, M. 1971. Lower Ordovician conodonts of Europe, p. 2161. In Sweet, W. C. and Bergström, S. M. (eds.), Symposium on Conodont Biostratigraphy. Geological Society of America Memoir 127, 499 p. Google Scholar
Linnemann, U., Romer, R. L., Pin, C., Alexandrovski, P., Buła, Z., Geisler, T., Kachlik, V., Kremińska, E., Mazur, S., Motuza, G., Murphy, J. B., Nance, D. D., Pisarevsky, S. A., Schultz, B., Ulrich, J., Wiszniewska, J., Żaba, J., and Zeh, A. 2008. Precambrian, p. 21101. In McCann, T. (ed.), The Geology of Central Europe. Vol. 1: Precambrian and Palaeozoic. Geological Society of London, London.Google Scholar
Löfgren, A. 1978. Arenigian and Llanvirnian conodonts from Jämtland, northern Sweden. Fossils and Strata 13, 129 p.Google Scholar
Löfgren, A. 1997. Conodont faunas from the upper Tremadoc at Brattefors, south-central Sweden, and reconstruction of the Paltodus apparatus. GFF, 119:257266.Google Scholar
McLearn, F. H. 1915. The Lower Ordovician (Tetragraptus Zone) at Saint John, New Brunswick, and the new genus Protistograptus . American Journal of Science, Series 4, 40:4959.Google Scholar
Matthew, G. F. 1893. Illustrations of the fauna of the St. John Group, No. 7. Transactions of the Royal Society of Canada, 10(4):95109.Google Scholar
Matthew, G. F. 1901. New species of Cambrian fossils from Cape Breton. Bulletin of the Natural Historical Society of New Brunswick, 4:269286.Google Scholar
Matthew, G. F. 1903. Report on the Cambrian rocks of Cape Breton. Geological Survey of Canada, Publication 797.Google Scholar
Mellgren, J. S. and Eriksson, M. E. 2006. A model of reconstruction for the oral apparatus of the Ordovician conodont genus Protopanderodus Lindström, 1971. Transactions of the Royal Society of Edinburgh, Earth Sciences, 97:97112.Google Scholar
Miller, R. F. 1988. Catalogue of type fossils in the New Brunswick Museum. Publications in Natural Science of the New Brunswick Museum, 7, 75 p.Google Scholar
Miller, W. 1987. Giant Bathysiphon (Foraminiferida) from Cretaceous turbidites, northern California. Lethaia, 21:363374.Google Scholar
Miller, W. 2005. Giant Bathysiphon (Astrorhizina: foraminifera) from the Cretaceous Hunders Cove Formation, southwestern Oregon. Journal of Paleontology, 79:389394.Google Scholar
Miller, W. 2008. A Bathysiphon (foraminifera) ‘shell bed’ from the Cretaceous of northern California, USA: example of a parautochthonous macro-skeletal deposit in deep-sea turbidites. Palaeogeography, Palaeoclimatology, Palaeoecology, 260:342346.Google Scholar
Moberg, J. C. and Möller, H. 1898. Om Acerocarenzonen. Geologiska Föreningens i Stockholm Förhandlingar, 20:198290.Google Scholar
Mound, M. 1965. Two new conodont genera from the Joins Formation (lower Middle Ordovician) of Oklahoma. Biological Society of Washington Proceedings, 78:193200.Google Scholar
Müller, K. J. 1964. Conodonten aus dem Unteren Ordovicium von Sudkorea. Neues Jahrbuch der Geologie und Paläontologie, Abhandlungen, 119:93102.Google Scholar
Neilsen, A. T. 2004. Ordovician sea-level changes: a Baltoscandian perspective, p. 8493. In Webby, B. D., Paris, F., Droser, M. L., and Percival, I. G. (eds.), The Great Ordovician Biodiversification Event. Columbia University Press, New York, 484 p.Google Scholar
Nicholson, H. A. 1873. Contributions to the study of the errant annelids of the older Palaeozoic rocks. Royal Society of London Proceedings, 21:288290.Google Scholar
Nickolaisen, F. and Henningsmoen, G. 1985. Upper Cambrian and lower Tremadoc trilobites from the Digermul Peninsula, Finmark, northern Norway. Norges Geologiske Untersøkelse Bulletin, 400:149.Google Scholar
North American Commission on Stratigraphic Nomenclature. 1983. North American Stratigraphic Code. American Association of Petroleum Geologists Bulletin, 67:851875.Google Scholar
Owens, R. M., Fortey, R. A., Cope, J. C. W., Rushton, A. W. A., and Bassett, M. G. 1982. Tremadoc faunas from the Carmarthen District, South Wales. Geological Magazine, 119:138.Google Scholar
Pander, C. H. 1856. Monographie der fossilen Fische des silurischen Systems der russisch-baltischen Gouvernements. Konglische Akademie des Wissenschaften, St. Petersburg.Google Scholar
Poumot, C. 1968. Amphorchitina, Ollachitina, Valatachitina; tois noveaux genres de chitinozoaires de l'Erg oriental (Algérie-Tunisie). Bulletin du Centre de Recherche de Pau, 2:4555.Google Scholar
Ranger, M. J., Pickerill, R. K., and Fillion, D. 1984. Lithostratigraphy of the Cambrian?-Lower Ordovician Bell Island and Wabana Groups of Bell Island, Little Bell, and Kellys Islands, Conception Bay, eastern Newfoundland. Canadian Journal of Earth Sciences, 21:12451261.Google Scholar
Rast, N., O'Brien, B. H., and Wardle, R. F. J. 1976. Relationships between Precambrian and lower Palaeozoic rocks of the ‘Avalon Platform’ in New Brunswick, the northeast Appalachians and the British Isles. Tectonophysics, 30:315338.CrossRefGoogle Scholar
Robison, R. and Pantoja-Alor, J. 1968. Tremadocian trilobites from the Nochitlan region, Oaxaca, Mexico. Journal of Paleontology, 42:767800.Google Scholar
Rushton, A. W. A. 1982. The biostratigraphy and correlation of the Merioneth–Tremadoc Series boundary in North Wales, p. 4160. In Bassett, M. G. and Dean, W. T. (eds.), The Cambrian-Ordovician Boundary. National Museum of Wales, Cardiff.Google Scholar
Rushton, A. W. A. 1988. Tremadoc trilobites from the Skiddaw Group in the English Lake District. Paleontology, 31:677698.Google Scholar
Sageman, B. B., Wignall, P. B., and Kauffman, E. G. 1991. Biofacies models for oxygen-deficient epicontinental seas: tool for paleoenvironmental analysis, p. 3059. In Einsele, G., Ricken, W., and Seilacher, A. (eds.), Cycles and Environments in Stratigraphy. Springer-Verlag, New York.Google Scholar
Saja, D. B., Pfefferkorn, H. W., and Phillips, S. P. 2009. Bathysiphon (Foraminiferida) at Pacheo Pass, California: a geopetal, paleocurrent, and paleobathymetric indicator in the Franciscan complex. Palaios, 24:181191.Google Scholar
Salter, J. W. 1866. Appendix.on the fossils of North Wales. Geological Survey of Great Britain, Memoir, 3:240381.Google Scholar
Sars, G. O. 1872. Undersøgelser ofver Hardangerfjordens Fauna. Videnskaps-Selske Christiana, Förhandlingar, volume for 1871, p. 246255.Google Scholar
Sergeeva, S. P. 1963. Conodonts from the Lower Ordovician of the Leningrad region. Paleontologoskoy Zhurnal (2), 93108. (In Russian).Google Scholar
Sexton, A. J. 1985. Geology of the Sporting Mountain area, southeastern Cape Breton Island, Nova Scotia. Geological Survey of Canada, Precambrian Division, Open File Report 1236, 136 p.Google Scholar
Smith, M. P. 1991. Early Ordovician conodonts of East and North Greenland. Meddelelser om Grønland, 26:181.Google Scholar
Speyer, S. E. 1985. Moulting in phacopid trilobites. Transactions of the Royal Society of Edinburgh, Earth Sciences, 76:239254.Google Scholar
Speyer, S. E. and Brett, C. E. 1985. Clustered trilobite assemblages in the Middle Devonian Hamilton Group. Lethaia, 18:85103.Google Scholar
Streng, M., Mellbin, B. B., Landing, E., and Keppie, J. D. 2011. Linguliform brachiopods from the terminal Cambrian and lowest Ordovician of the Oaxaquia microcontinent (southern Mexico). Journal of Paleontology, 85:122155.Google Scholar
Sweet, W. C. and Bergström, S. M. 1972. Multielement taxonomy and Ordovician conodonts. Geologica et Palaeontologica, 1:2942.Google Scholar
Swinnerton, H. H. 1915. Suggestions for a revised classification of trilobites. Geological Magazine, 2:407496.CrossRefGoogle Scholar
Tanoli, S. K. and Pickerill, R. K. 1988. Lithostratigraphy of the Cambrian-Lower Ordovician Saint John Group, southern New Brunswick. Canadian Journal of Earth Science, 25:669690.Google Scholar
Van Ingen, G. 1914. Table of geological formations of the Cambrian and Ordovician Systems about Conception and Trinity Bays, Newfoundland. Princeton University Contributions to the Geology of Newfoundland, No. 4, 1 p.Google Scholar
Van Wamel, W. A. 1974. Conodont biostratigraphy of the Upper Cambrian and Lower Ordovician of north-western Öland, southeastern Sweden. Utrecht Micropaleontological Bulletins, 10, 126 p.Google Scholar
Walch, J. E. I. 1771. Die Naturgeschichte der Versteinerungen, zur Erläuterung der knorrischen Sammlung von Merkwürdigkeiten der Natur. Dritter Theil, Paul Jonathan Feistecker, Nürnburg, 235 p.Google Scholar
Walcott, C. D. 1884. Paleontology of the Eureka District. Monographs of the United States Geological Survey, 3.Google Scholar
Walcott, C. D. 1912. Cambrian Brachiopoda. Monographs of the United States Geological Survey, 51.Google Scholar
Webby, B. D., Cooper, R. A., Bergström, S. M., and Paris, F. 2004. Stratigraphic framework and time slices, p. 4148. In Webby, B. D., Paris, F., Droser, M. L., and Percival, I. G. (eds.), The Great Ordovician Biodiversification Event. Columbia University Press, New York, 484 p.Google Scholar
Weeks, L. J. 1947. Mira-Framboise, Richmond and Cape Breton Counties, Nova Scotia. Geological Survey of Canada Paper 47-17, 1 p.Google Scholar
Williams, H. and Hatcher, R. D. 1984. Suspect terranes and accretionary history of the Appalachian orogen. Geology, 10:530536.Google Scholar
Zeballo, F. J., Albanesi, G. L., and Ortega, G. 2008. New late Tremadocian (Early Ordovician) conodont and graptolite records from the southern South American Gondwana margin (Eastern Cordillera, Argentina). Geologica Acta, 6:131145.Google Scholar
Zhen, Y. Y., Percival, I. G., and Liu, J. B. 2006. Early Ordovician Triangulodus (Conodonta) from the Honghuayuan Formation of Guizhou, South China. Alcheringa, 31:191212.Google Scholar