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Lower Cambrian acritarchs from northern Spain: the Precambrian-Cambrian boundary and biostratigraphic implications

Published online by Cambridge University Press:  01 May 2009

Teodoro Palacios
Affiliation:
Universidad de Extremadura, Facultad de Ciencias, Area de Paleontologia, 06071 Badajoz, Spain
Gonzalo Vidal
Affiliation:
Uppsala University, Micropalaeontological Laboratory, Institute of Palaeontology, Box 558, S-751 22 Uppsala, Sweden

Abstract

Acritarchs are reported from basal Cambrian rock units inthe Cantabrian region of northern Spain that are known to contain archaeocyathan and trilobite faunas. Biostratigraphic correlation of the Iberian sequences with other regions has been hampered by the strong provincialism of these faunas. However, this report of evidently cosmopolitan acritarch taxaestablishes the time equivalence of early Cambrian trilobite faunas from Iberia, Baltoscandia and the East European Platform (EEP). Our data suggest that the detrital deposition of the Lower Cambrian Herreria Formation embraces at least three (and possibly four) Lower Cambrian acritarch zones previously identified in the EEP, eastern Siberia, Baltoscandia, Scotland, Greenland, Svalbard and western North America. The early Cambrian transgression in northern Spain was probably initiated in Talsy times (Schmidtiellus mickwitzi trilobite Zone in Baltoscandia and the EEP), in part corresponding to the Dokidocyathus regularis archaeocyathian Zone of the Middle Tommotian in Siberia.

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Articles
Copyright
Copyright © Cambridge University Press 1992

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References

Brasier, M. D. 1979. The Cambrian radiation event. In The Origin of Major Invertebrate Groups (ed. House, M. R.), pp. 103–59. London, New York: Academic Press.Google Scholar
Brasier, M. D. 1982. Sea-level changes, facies changes and the Late Precambrian-Early Cambrian evolutionary explosion. Precambrian Research 17, 105–23.CrossRefGoogle Scholar
Brasier, M. D. 1990. Nutrients in the early Cambrian. Nature 347, 521–2.CrossRefGoogle Scholar
Brasier, M. D. & Cowie, J. W. 1989. Other areas: Northwest Canada; California, Nevada, and Mexico; Morocco, Spain, and France. In The Precambrian-Cambrian Boundary (eds Cowie, J. W. and Brasier, M. D.), pp. 105–14. Oxford University Press.Google Scholar
Brasier, M. D., PerejóN, A. & San José, M. D. DE 1979. Discovery of an important fossiliferous Precambrian-Cambrian sequence in Spain. Estudios de Geologia 35, 379–83.Google Scholar
Colbath, G. K. 1990. Palaeobiogeography of Middle Palaeozoic organic-walledphytoplankton. In Palaeozoic Palaeogeography and Biogeography (eds McKerrow, W. S. & Scotese, C. R.), pp. 207–13. Geological Society Memoir no. 12.Google Scholar
Comté, P. 1937. La série cambrienne et silurienne du León. Comptes Rendus de l' Académie des Sciences 202, 337–41.Google Scholar
Comté, P. 1938. La succession lithologique de formations cambriennesdu León. Comptes Rendus de l' Académie des Sciences 204, 181–3.Google Scholar
Comté, P. 1959. Recherches sur les terrains anciens de la CordillereCantabrique. Memorias del Instituto Geo-logico y Minero de España 60, 1425.Google Scholar
Conway Morris, S. 1987. The search for the Precambrian-Cambrian boundary. American Scientist 75, 156–67.Google Scholar
Cowie, J. W. & Brasier, M. D. (eds) 1989. The Pre-cambrian-Cambrian Boundary. Oxford University Press. 213 pp.Google Scholar
Cowie, J. W. 1989. Introduction. In The Precambrian-Cambrian Boundary (eds Cowie, J. W. and Brasier, M. D.), pp. 36. Oxford University Press.Google Scholar
Cramer, F. H. 1968. Silurian palynologic microfossils and paleolatitudes. Neues Jahrbuch für Geologie und Paläontologie, Monatshefte 10, 591–7.Google Scholar
Cramer, F. H. 1970 a. Distribution of selected Silurian acritarchs. Revista Espanola Micropaleontologia, Numero Extraordinario 1, 1203.Google Scholar
Cramer, F. H. 1970 b. Middle Silurian continental movement estimated from phytoplankton-facies transgression. Earth and Planetary Science Letters 19, 8793.CrossRefGoogle Scholar
Cramer, F. H. & Diez, M. D. C. R. 1972. North American Silurian palynofacies and their spatial arrangement: acritarchs. Palaeontographia B 138, 107–80.Google Scholar
Cramer, F. H. & Diez, M. D. C. R. 1974. Early Paleozoic palynomorph provinces and paleoclimate. In Paleographic Provinces and Provinciality (ed. Ross, C. A.), pp. 177–88. Society of Economic Paleontologists and Mineralogists, Special Publication no. 21.CrossRefGoogle Scholar
Crimes, T. P. 1987. Trace-fossils and the Precambrian-Cambrian boundary. Geological Magazine 124, 97119.CrossRefGoogle Scholar
Crimes, T. P. 1989. Trace fossils. In The Precambrian-Cambrian Boundary (eds Cowie, J. W. and Brasier, M. D.), pp. 167185. Oxford University Press.Google Scholar
Crimes, P. T. & Anderson, M. M. 1985. Trace fossils from Late Precambrian-Early Cambrian strata at south-Google Scholar
Crimes, P. T. & ANDERSON, M. M. 1985. Trace fossils from late Precambrian-Early Cambrian strata at southeastern Newfoundland (Canada): Temporal and environmental implications. Journal of Paleontology 59, 310–43.Google Scholar
Crimes, T. P., Legg, I., Marcos, A. & Arboleya, M. 1977. Late Precambrian-low Lower Cambrian trace fossils from Spain. In Trace Fossils 2 (eds Crimes, T. P. and Harper, J. C.), pp. 91139. Geological Journal Special Issue no. 9.Google Scholar
Debrenne, F. & Lotze, F. 1963. Die Archaeocyatha das Spanischen Kambriums. Akademie der Wissenschaft und der Literatur Abhandlungen der Natuswissen-schaftligen Klase 2, 107–44.Google Scholar
Debrenne, F. & Zamarreño, I. 1970. Sur la découverte d' Archéocyathes dans le Cambrien du NW de l'Espagne. Breviora Geologica Astúrica 14 (1), 111.Google Scholar
Debrenne, F. & Zamarreño, I. 1975. Sur la faune d'Archéocyathes de a Formatión Vegadeo et leur rapport avec la distribution des facies carbonates dans le NW de l'Espagne. Breviora Geologica Astúrica 19, (2), 1727.Google Scholar
Diez Balda, M. A. 1986. El Complejo Esquisto-Grau-váquico, las series paleozoicas y la estructura hercinica al Sur de Salamanca. Acta Salmanticensia, Secion de Ciencias 52, 1162.Google Scholar
Diez Balda, M. A. & Fournier Vinas, Ch. 1981. Hallazgo de acritarcos en el Complejo Esquisto-Grauváquico al Sur de salamamca. Acta GeologicaHisádnica 16 (3), 131–4.Google Scholar
Diez Balda, M. A., Vegas, R. & Gonzalez Lodeiro, F. 1990. Part IV, Central Iberian Zone. Structures. In Pre-Mesozoic Geology of Iberia (eds Dallmeyer, R. D. & Garcia, E. Martinez), pp. 172–88. Springer-Verlag.Google Scholar
Downie, C. 1982. Lower Cambrian acritarchs from Scotland, Norway, Greenlandand Canada. Transactions, Royal Society of Edinburgh, Earth Sciences 72, 257–85.Google Scholar
Eklund, C. 1990. Lower Cambrian acritarch stratigraphy of the Bårstad2 core, Ostergötland, Sweden. Geologiska Föreningens i Stockholm Förhandlingar 112, 1944.CrossRefGoogle Scholar
Fedonkin, M., Liñán, E. & Perejón, A. 1983. Icnofósiles de las rocas precámbrico-cámbricas de la Sierra de Cordoba, España. Boletin de la Real Sociedad Española Hostoria Natural (Geologia) 81, (1–2), 514.Google Scholar
Fombella, M. A. 1977. Acritarcos de edad Cambrico Medio inferior de la provincia de León. Revista Española de Micropaleontogia 9, 115–25.Google Scholar
Fombella, M. A. 1978. Acritarcos de la Formación Oville, edad Cambrico medio-Tremadoc, Provincia de León, España. Palinologia n° extraordinario, 1, 245–61.Google Scholar
Fombella, M. A. 1979. Palinologia de la Formación Oville al N y S dela Cordillera Cantña. Palinogia 1, 117.Google Scholar
Gamez, J. A., Neito, C., Gozalo, R., Liñán, E. Mandado, J. & Palacios, T. (in press). Bioestratigrafia del Cambrico de Borobia, Provincia de Soria. Cadenas Ibéricas Orientales. Cuadernos del laboratorio xeologico de Laxe (in press).Google Scholar
Gil Cid, M. D. & Jago, J. B. 1989. New data on the Lower Cambrian Trilobites of Cortijos de Malagon (Spain). Estudios de Geologia 45, 91–9.Google Scholar
Gil Cid, M. D. 1988. Redlichiidae del Cambrico inferior de Los Navalucillos(Toledo). Boletin Geológico Minero 99(4), 584–91.Google Scholar
Gil Cid, M. D., PerejóN, A. & San José, M. A. DE 1976. Estratigrafia y Paleontologia de las calizas cambricas de Los Navalucillos (Toledo). Tecniterrae 13, 119.Google Scholar
Glaessner, M. 1984. The Dawn of Animal Life-A Biohistorical Study, 244 pp. Cambridge University Press.Google Scholar
Gower, J. F. R., Denman, K. L. & Holyer, R. J. 1980. Phytoplankton patchiness indicates the fluctuation of mesoscale oceanic structure. Nature 288, 157–9.CrossRefGoogle Scholar
Grant, S.W. F. 1990. Shell structure and distribution of Claudina, apotential index fossil for the terminal Proterozoic. American Journal of Science 290 A, 261–94.Google Scholar
Hayes, J. M., Kaplan, I. R. & Wedeking, W. 1983. Precambrian Organic Geochemistry, Preservation of the Record. In Earth's Earliest Biosphere (ed. Schopf, J. W.), pp. 93134. Princeton University Press.Google Scholar
Hill, P. J. & Molyneux, S. G. 1988. Biostratigraphy, palynofacies and provincialism of Late Ordo-vician-Early Silurian acritarchs from northeast Libya. In Subsurface Palynostratigraphy of Northeast Libya (eds El-Arnauti, A., Owens, B. & Thusu, B.), pp. 2743. Benghazi: Garyounis University.Google Scholar
Jacobson, S. R. 1979. Acritarchs as paleoenvironmental indicators in Middleand Upper Ordovician rocks from Kentucky, Ohio and New York Journal of Paleontology 53, 1197–212.Google Scholar
Julivert, M. & Martinez Garcia, E. 1967. Sobre el contacto entre el Cámbrico y el Precámbrico en la parte meridional de la Cordillera Cantábrica y el papel del Precámbrico en la Orogénesis Hercinica. Acta Geologica Hispánica 2, 107–10.Google Scholar
Knoll, A. H. & Swett, K. 1987. Micropalaeontology across the Precambrian-Cambrian boundary in Spitsbergen. Journal of Paleontology 61, 898926.CrossRefGoogle Scholar
Knoll, A. H., Hayes, J. M., Kaufman, A. J., Swett, K. & Lambert, I. B. 1986. Secular variations in carbon isotope ratios from Upper Proterozoic successions of Svalbard and East Greenland. Nature 321, 832–8.CrossRefGoogle ScholarPubMed
Liñán, E. 1978. Bioestratigrai de la Sierra de Córdoba. Tesis doctoral de la Universidad de Granada, 191, 1212 (published).Google Scholar
Liñán, E. 1984. Introduction al problema de la Palaeo-geografia del Cambrico en Ossa-Morena. Cuadernos del laboratorio xeologico de Laxe 8, 283314.Google Scholar
Liñán, E. & Fernandez Carrasco, J. 1984. La formación Torreárboles y la Paleogeografia del limite Pre-cámbrico-Cambrico en Ossa-Morena (Flanco Norte de la alincación Olivenza-Monesterio). Cuadernos del laboratio xeologico de Laxe 8, 315–28.Google Scholar
Liñán, E. & Palacios, T. 1983. Aportaciones micro-paleontológicas para el conocimiento del limite Pre-cambrico-Cambrico en la Sierra de Córdoba, España. Communicacoes dos Servicos Geologicos de Portugal 69 (2), 227–34.Google Scholar
Liñán, E. & Palacios, T. 1987. Asociaciones de Pistas fosilesy microorganismos de pared orgánica del Proterozoico en las facies esquisto-grauváquicas del Norte de Caceres. Consecuencias regionales. Boletin de la Real Sociedad Española de Historia Natural (Geo-logia) 82, 211–32.Google Scholar
Liñán, E. & PerejóN, A. 1981. El Cambrico inferior de la ‘Unidad de Alconera’, Badajoz (SW de España). Boletin de la Real Sociedad Española de Historia Natural (Geologi) 79, 125–48.Google Scholar
Liñán, E. & Sdzuy, K. 1978. A trilobite from the Lower Cambrian of Córdoba (Spain), and its stratigraphical significance. Seckenbergiana Lethaea 59, 387–99.Google Scholar
Liñán, E. & Tejero, R. 1988. Las formaciones precambricas delantiforme de Paracuellos (Cadenas Ibéricas). Boletin de la Real Sociedad Española de Historia Natural (Geologia) 84, 3949.Google Scholar
Liñán, E., Palacios, T. & PerejóN, A. 1984. Precambrian-Cambrian boundary and correlation from southwestern and central part of Spain. Geological Magazine 121, 221–8.CrossRefGoogle Scholar
Lotze, F. 1945. Zur Gliederung der Varisziden der Iberischen Meseta. Feotektektonische Forschungen 6, 7892.Google Scholar
Lotze, F. 1956. Das Prakambrium Spaniens. Neues Jahr-buch für Geologie und Paläontologie Monatschefte 8, 373–80.Google Scholar
Lotze, F. & Sdzuy, K. 1961. Das Kambrium Spaniens. Teil I Stratigraphie. Akademie der Wissenschaft und der Literatur Abhandlungen der Natuswissenschaftilgen Klase 6–8, 1216.Google Scholar
Lowenstam, H. A. & Margulis, L. 1980. Evolutionary prerequistes for early Phanerozoic calcereous skeletons. Bio Systems 12, 2741.CrossRefGoogle Scholar
Macpherson, J. 1878. Sobre la existencia de la fauna primordial en la provincia de Sevilla. Anales de la Sociedad Española de Historia Natural 7, 281–4.Google Scholar
Marcos, A. 1973. Las series del Paleozoico inferior y la estructura herciniana del occidente de Asturias (NW de España). Trabajos de Geologia 6, 3113.Google Scholar
Moczydlowska, M. 1991. Acritarch biostratigraphy of the Lower Cambrian and the Precambian-Cambrian boundary in southeastern Poland. Fossils and Strata 29, 127 pp.Google Scholar
Moczydlowska, M. & Vidal, G. 1986. Lower Cambrian acritarch zonation in southern Scandinavia and southeastern Poland. Geologiska Föreningens i Stockholm Forhandlingar 108, 201223.CrossRefGoogle Scholar
Moczydlowska, M. & Vidal, G. 1988. Early Cambrian acritarchs from Scandinavia and Poland. Palynology 12, 110.CrossRefGoogle Scholar
Moczydlowska, M. & Vidal, G. (in press). Phytoplankton from the Lower Cambrian Laeså Formation on Born-holm, Denmark: biostratigraphy and palaeoenvironmental constraints. Geological Magazine.Google Scholar
Moreno, F., Vegas, R. & Marcos, A. 1977. Sobre la ecad de las series ordovicicas y cámbricas relacionadas con la discordancia ‘Sardica’ en el Anticlinal de Valdelacasa (Montes de Toledo, España). Breviora Geologica Asturica 20, 816.Google Scholar
Nautiyal, A. C. 1977. The paleogeographic distribution of Devonian acritarchs and biofacies belts. Journal of the Geological Society of India 18, 5364.Google Scholar
Palacios, T. 1983. Primeros microfósiles de pared orgánica extraidos en el olistostroma del Membrillar (Proterozoico superior del Centrode España). Revista Española de Micropaleontologia 60, 511–17.Google Scholar
Palacios, T. 1989. Microfósiles de pared orgánica del Proterozoico superior (Región Central de la Peninsula Ibérica). Memorias del Museo Paleontológico de la Universidad de Zaragoza 3, 191.Google Scholar
PerejóN., A. 1986. Bioestratigrafia de los Arqueociatos en España. Cuadernos de Geologia Ibérica 9, 213–65.Google Scholar
Perez Estaun, A. 1973. Datos sobre la sucesión estrati-gráfica del Precámbrico y la estructura del extremo sur del antiforme del Narcea (NW de España). Breviora Geologica Astúrica 17, 516.Google Scholar
Perez Estaun, A. 1978. Estratigrafia y estructura de la Rama S. de la zona Asturoccidental-Leonesa. Memorias del Instituto Geologico y Minero de España 92, 1150.Google Scholar
Pollard, R. T. & Regier, L. 1990. Large variations in potential vorticity at small spatial scales in the upper ocean. Nature 348, 227–9.CrossRefGoogle Scholar
Prado, C. 1855. Memoire sur la géologie d'Almaden, d'une partie de la Sierra Morena et des Montagnes de Tolède. Bulletin dela Société Géologique de France, Série 2, 12, 124, 182–204.Google Scholar
Quesada, C., Apalategui, O., Eguiluz, L., Liñán, E. & Palacios, T. 1990. Part V. Ossa-Morena Zone. 2. Stratigraphy. In Pre-Mesozoic Geology of Iberia (eds Dallmeyer, R. D. & Garcia, E. Martinez), pp. 252–8. Springer-Verlag.CrossRefGoogle Scholar
Robles, R. & Alvarez Nava, H. 1988. Los materials precambricos-cambricos del Domo de las Hurdes: Existencia de tres series sedimentarias separadas por discordancias, SO de Salamanca (Zona Centro Ibérica). II Congreso Geologico de España Granada Comunidad 1, 185–88.Google Scholar
Rovnina, L. V. 1981. Palynological Method to Determine the Level of Katagenesis of Organic Matter by Using Jurassic Deposits of Western Siberia. In Organic Maturation Studies and Fossil Fuel Exploration (ed. Brooks, J. G.), pp. 427432. Academic Press, London.Google Scholar
Rozanov, A. Yu. & Debrenne, F. 1974. Age of archaeo-cyathid assemblages. American Journal of Science 274, 833–48.CrossRefGoogle Scholar
Runnegar, B. 1982. The Cambrian explosion: animals or fossils? Journal of the Geological Society of Australia 29, 395411.CrossRefGoogle Scholar
San José, M. A. DE, Pieren, A. P., Garcia Hildalgo, F. J., Vilas, L., Herranz, P., Pelaez, J. R. & PerejóN, A. 1990. Part IV Central Iberian Zone. Ante-Ordovician Stratigraphy. In Pre-Mesozoic Geology of Iberia (eds. Dallmeyer, R. D. & Garcia, E. Martinez), pp. 147–59. Springer-Verlag.Google Scholar
Sdzuy, K. 1961. Das Kambrium Spaniens Teill II. Trilobiten. Akademie derWissenschaft und der Literatur Abhandlungen der Natuswissenschaftligen Klase, 6, 7, 8, 217408.Google Scholar
Sdzuy, K. 1969. Bioestratigrafia de la Griotte cámbrica de los Barrios de Luna (León) y de otras sucesiones comparables. Trabajos de Geologi 2, 4585.Google Scholar
Sdzuy, K. 1971. Acerca de la correlación del C´mbrico inferior en la Peninsula Ibérica. I Congreso Hispano-Luso Americano Geologia Economica Seccion 1, Geologia 2, 753–68.Google Scholar
Sdzuy, K. 1987. Trilobites de la base de la formación del Jalón (Cambrico inferior) de Aragon. Revista Española de Paleontologia 2, 38.Google Scholar
Sepkoski, J. J., 1979. A kinetic model of Phanerozoic taxonomic diversity II. Early Phanerozoic families and multiple equilibria. Paleobiology 5, 222–51.CrossRefGoogle Scholar
Sitter, L. U. 1961. Le Précambrien dans la Chaîne Cantabrique. Comptes Rendus de l'Académie des Sciences 9, 1253.Google Scholar
Stanley, S. M. 1976. Fossil data and the Precambrian–Cambrian evolutionary transition. American Journal of Science 276, 5676.CrossRefGoogle Scholar
Theokritoff, G. 1979. Early Cambrian provincialism and biogeographic boundaries in the North American region. Lethaia 12, 281–96.CrossRefGoogle Scholar
Towe, K. M. 1970. Oxygen–collagen priority and the early fossil record. Proceedings, National Academy of Sciences 65, 781–88.CrossRefGoogle Scholar
Towe, K. M. 1981. Biochemical keys to the emergence of complex life. in Life in the Universe (ed. Billingham, J.), pp. 297306. Cambridge, Mass.: MIT Press.Google Scholar
Truyols, J., Arbizu, M. A., Garcia Alcalde, J. L., Garcia Lopez, S., Arbizu, M. A. & Soto, F. 1990. Part II: Cantabrian and Palentian Zones. The Asturian-Leonese Domain (Cantabrian Zone). In Pre-Mesozoic Geology of Iberia (eds Dallmeyer, R. D. & Garcia, E. Martinez), pp. 1019. Springer-Verlag.Google Scholar
Valenzuela, J. I., Gamez, J. A., Liñán, E. & Sdzuy, K. 1990. Estratigrafia del Cámbrico de la Region de Brea. Cadena Ibérica Oriental. Boletin de la Real Sociedad Española de Historia Natural (Secion de Geologia) 85, 4554.Google Scholar
Vanguestaine, M. 1974. Espèces zonales d'Acritarches du Cambro–Trémadocien de Belgique et de l'Ardenne francaise. Review of Palaeobotany and Palynology 18, 6382.CrossRefGoogle Scholar
Vavrdová, M. 1974. Geographical differentiation of Ordovician acritarch assemblages in Europe. Review of Palaeobotany and Palynology 18, 171–6.CrossRefGoogle Scholar
Vavrdová, M. 1982. Phytoplankton communities of Cambrian and Ordovician age of Central Bohemia. Vestnik Ustredniho Ustavu Geologickeho 57, 145–55.Google Scholar
Vidal, G. 1985. Biostratigraphic correlation of the Upper Proterozoic and Lower Cambrian of the Fennoscandian Shield and the Caledonides of East Greenland and Svalbard. In The Caledonide Orogoen - Scandinavia and Related Areas, Part 1 (eds Gee, D. G. & Sturt, B. A.), pp. 331–8. John Wiley & Sons, Chichester.Google Scholar
Vidal, G. 1988. A palynological preparation method. Palynolgy 12, 215–20.CrossRefGoogle Scholar
Vidal, G. & Knoll, A. H. 1983. Proterozoic plankton. Geological Society of America, Memoir 30, 265–77.CrossRefGoogle Scholar
Vidal, G. & Nystuen, J. P. 1990. Lower Cambrian acritarchs and Proterozoic–Cambrian boundary in southern Norway. Norsk Geologisk Tidskrift 70, 191222.Google Scholar
Volkova, N. A. 1968. Acritarchs from Precambrian and Cambrian deposits in Estonia. In Problematics of Riphean and Cambrian of the Russian Platform, Urals and Kazakhstan (ed. Keller, B. M.), pp. 836. Academy of Sciences USSR, Nauka, Moscow (in Russian).Google Scholar
Volkova, N. A. 1969. Distribution of acritarchs in the north-eastern Poland. In Tommotian Stage and the Cambrian lower boundary problem (eds Rozanov, A.Yu. et al. ,), pp. 74–6. Nauka, Moscow.Google Scholar
Volkova, N. A., Kirjanov, V. V., Piscun, L. V., Paske–Viciene, L. T. & Jankauskas, T. V. 1983. Plant Microfossils. In Upper Precambrian and Cambrian Palaeontology of the East European Platform (eds Urbanek, A. and Rozanov, A. Yu.), pp. 746. War-szawa: Publishing House Wydawnictwa Geologiczne.Google Scholar
Wood, G. D. & Stephenson, J. T. 1989. Cambrian palynomorphs from the warm–water provincial realm, Bonneterre and Davis Formations of Missouri and Arkansas (Reelfoot Rift area): biostratigraphy, paleoecology and thermal maturity. In Field Guide to the Upper Cambrian of Southeastern Missouri: Stratigraphy, Sedimentology and Economic Geology (eds Gregg, J. M., Palmer, J. R. & Kurtz, V. E.), pp. 84102. Department of Geology and Geophysics, University of Missouri (Rolla), Geological Society of Amercia Field Trip (Annual Meeting).Google Scholar
Yin, Leiming, 1985. Microfossils of the Doushantuo Formation in the Yangtze Gorge district, western Hubei. Palaeontologia Cathayana 2, 229–49.Google Scholar
Zamarreño, I. 1972. Las Litofacies carbonatadas del Cambrico de la Zona Cantábrica (NW España) y su distribución paleogeográfica. Trabajos de Geologia 5, 1118.Google Scholar
Zamarreño, I. & Perejón, A. 1972. El nivel carbonatado del Cámbrico de Piedrafita (Zona Astur-Occidental Leonea, NW de España): Tipos de facies y faunas de Arqueociatos. Breviora Geologica Astúrica 20, 1732.Google Scholar