<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>1405-3322</journal-id>
<journal-title><![CDATA[Boletín de la Sociedad Geológica Mexicana]]></journal-title>
<abbrev-journal-title><![CDATA[Bol. Soc. Geol. Mex]]></abbrev-journal-title>
<issn>1405-3322</issn>
<publisher>
<publisher-name><![CDATA[Sociedad Geológica Mexicana A.C.]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S1405-33222016000300429</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Cambrian Stratigraphy of San José de Gracia, Sonora, Mexico: El Gavilán Formation, a new lithostratigraphic unit of middle Cambrian open shelf environment]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Cuen-Romero]]></surname>
<given-names><![CDATA[Francisco Javier]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Valdez Holguín]]></surname>
<given-names><![CDATA[José Eduardo]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Buitrón]]></surname>
<given-names><![CDATA[Blanca Estela]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Monreal]]></surname>
<given-names><![CDATA[Rogelio]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Sundberg]]></surname>
<given-names><![CDATA[Frederick]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Montijo González]]></surname>
<given-names><![CDATA[Alejandra]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Minjarez Sosa]]></surname>
<given-names><![CDATA[Ismael]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Universidad de Sonora Departamento de Geología ]]></institution>
<addr-line><![CDATA[Hermosillo Sonora]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Universidad de Sonora Departamento de Investigaciones Científicas y Tecnológicas ]]></institution>
<addr-line><![CDATA[Hermosillo Sonora]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,Universidad Nacional Autónoma de México Instituto de Geología Departamento de Paleontología]]></institution>
<addr-line><![CDATA[CDMX ]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af4">
<institution><![CDATA[,Show Low High School  ]]></institution>
<addr-line><![CDATA[Show Low AZ]]></addr-line>
<country>USA</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>12</month>
<year>2016</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>12</month>
<year>2016</year>
</pub-date>
<volume>68</volume>
<numero>3</numero>
<fpage>429</fpage>
<lpage>441</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S1405-33222016000300429&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S1405-33222016000300429&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S1405-33222016000300429&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract: An approximately 600 m interval of Cambrian strata is exposed near the town of San José de Gracia, Sonora, Mexico. This succession is divided into four formations, one of which is proposed here as a new formal stratigraphic unit: El Gavilán Formation, following the rules of the North American Commission on Stratigraphic Nomenclature. The new nomenclature reflects substantial lithologic differences, particularly in the middle Cambrian strata in comparison with other Cambrian rocks exposed in other parts of the state. The Proveedora Formation consists of bioturbated, fine-grained quartz arenite with ichnofossils; the Buelna Formation consists of interbedded limestone and sandstone, with abundant trilobites of either the ?Bristolia mohavensis or ?Bristolia insolens Zone (Series 2?, Stage 4?); the Cerro Prieto Formation is a highly recrystallized oolitic limestone with fragments of ?Amecephalus arrojosensis at the base, suggesting the A. arrojosensis Biozone (Series 2?; Stage 4?); and the El Gavilán Formation consists of interbedded limestone and intensely fractured red shale, with abundant fauna of the upper part of the Mexicella mexicana Zone, Albertella highlandensis Subzone, Ptychagnostus praecurrens Zone (open shelf) (Series 3?, Stage 5?). The Cambrian rocks of Sonora were deposited in the occidental part of the North American craton during the early and middle Cambrian, when Laurentia must have been constituted by terrestrial masses near the paleoequator, aligned in an east-west direction, providing the right conditions for an abundant invertebrate marine fauna.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen: Una sucesión estratigráfica del Cámbrico de aproximadamente 600 m de espesor aflora en San José de Gracia, Sonora, México. Esta sucesión está dividida en cuatro formaciones, una de las cuales se propone aquí como una nueva unidad estratigráfica formal: la Formación El Gavilán, siguiendo las reglas de North American Commission on Stratigraphic Nomenclature. La nueva nomenclatura refleja diferencias litológicas substanciales, particularmente en los estratos del Cámbrico medio en comparación con otras rocas cámbricas expuestas en otras ubicaciones del estado. Las formaciones Proveedora, Buelna, Cerro Prieto y El Gavilán constituyen una sucesión detrítico-carbonatada, la cual se expande sobre una porción considerable del Cámbrico inferior y medio en la Loma El Chihuarruita. Un amplio rango de ambientes de depósito se encuentra representado por la sucesión cámbrica en esta región, mostrando algunos cambios en comparación con las formaciones cámbricas del área de Caborca. La Formación Proveedora está compuesta por cuarzoarenita de grano fino con bioturbación e icnofósiles; la Formación Buelna consiste de una intercalación de caliza y arenisca, con abundante fauna del Cámbrico Serie 2?, Piso 4?, asignada a la Zona de ?Bristolia mohavensis o ?Bristoliainsolens ; la Formación Cerro Prieto es una caliza oolítica fuertemente recristalizada y con fragmentos de ?Amecephalusarrojosensis en su base, sugiriendo la Zona de Amecephalusarrojosensis (Serie 2?; Piso 4?); y la Formación El Gavilán consiste en una intercalación de caliza y lutita de color rojo intensamente fracturada, con abundante fauna del Cámbrico Serie 3?, Piso 5?, asignada a la parte superior de la Zona de Mexicellamexicana , Subzona de Albertellahighlandensis , Zona de Ptychagnostus praecurrens (plataforma abierta). Las rocas cámbricas de Sonora fueron depositadas en la parte occidental del cratón norteamericano, durante el Cámbrico temprano y medio. En estas épocas, Laurentia debió constituir masas terrestres cercanas al ecuador, alineadas en dirección este-oeste, proporcionando las condiciones que favorecieron una abundante fauna de invertebrados marinos.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Cambrian]]></kwd>
<kwd lng="en"><![CDATA[Stratigraphy]]></kwd>
<kwd lng="en"><![CDATA[Sonora]]></kwd>
<kwd lng="en"><![CDATA[Mexico]]></kwd>
<kwd lng="es"><![CDATA[Cámbrico]]></kwd>
<kwd lng="es"><![CDATA[Estratigrafía]]></kwd>
<kwd lng="es"><![CDATA[Sonora]]></kwd>
<kwd lng="es"><![CDATA[México]]></kwd>
</kwd-group>
</article-meta>
</front><back>
<ref-list>
<ref id="B1">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[El Cámbrico Temprano y Medio de San José de Gracia, Sonora Central, México]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Almazán-Vázquez]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<source><![CDATA[Unión Geofísica Mexicana]]></source>
<year>2002</year>
<volume>22</volume>
<numero>2</numero>
<issue>2</issue>
</nlm-citation>
</ref>
<ref id="B2">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Notas sobre el Paleozoico mexicano]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Álvarez]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
</person-group>
<source><![CDATA[Boletín de la Asociación Mexicana de Geólogos petroleros]]></source>
<year>1949</year>
<volume>1</volume>
<page-range>47-56</page-range></nlm-citation>
</ref>
<ref id="B3">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Babcock]]></surname>
<given-names><![CDATA[L.E.]]></given-names>
</name>
<name>
<surname><![CDATA[Robison]]></surname>
<given-names><![CDATA[R.A.]]></given-names>
</name>
</person-group>
<source><![CDATA[Taxonomy and paleobiology of some Middle Cambrian Scenella (Cnidaria) and hyolithids (Mollusca) from western North America]]></source>
<year>1988</year>
<volume>121</volume>
<page-range>1-22</page-range></nlm-citation>
</ref>
<ref id="B4">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Estratigrafía del Terciario y Geocronología (K - Ar) del área sur de San José de Gracia, Sonora central, México]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Bartolini]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
<name>
<surname><![CDATA[Morales-Montaño]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Damon]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
</person-group>
<source><![CDATA[Geological Society of America]]></source>
<year>2001</year>
<volume>24</volume>
</nlm-citation>
</ref>
<ref id="B5">
<nlm-citation citation-type="confpro">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Beraldi-Campesi]]></surname>
<given-names><![CDATA[H.]]></given-names>
</name>
<name>
<surname><![CDATA[Buitrón]]></surname>
<given-names><![CDATA[S.B.]]></given-names>
</name>
<name>
<surname><![CDATA[Cuen]]></surname>
<given-names><![CDATA[R.F.]]></given-names>
</name>
<name>
<surname><![CDATA[Montijo]]></surname>
<given-names><![CDATA[G.A.]]></given-names>
</name>
</person-group>
<source><![CDATA[Oncolitos del Cámbrico inferior de la región de San José de Gracia, Sonora]]></source>
<year>2013</year>
<conf-name><![CDATA[ VIIICongreso Latinoamericano de Paleontología]]></conf-name>
<conf-loc> </conf-loc>
</nlm-citation>
</ref>
<ref id="B6">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Buitrón]]></surname>
<given-names><![CDATA[B.E.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Las rocas sedimentarias del Paleozoico inferior de México y su contenido biótico]]></article-title>
<person-group person-group-type="editor">
<name>
<surname><![CDATA[Gutiérrez Marco]]></surname>
<given-names><![CDATA[J.G.]]></given-names>
</name>
<name>
<surname><![CDATA[Saavedra]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Rábano]]></surname>
<given-names><![CDATA[I.]]></given-names>
</name>
</person-group>
<source><![CDATA[Paleozoico inferior de Ibero-América]]></source>
<year>1992</year>
<page-range>193-201</page-range><publisher-name><![CDATA[Universidad de Extremadura]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B7">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Buitrón]]></surname>
<given-names><![CDATA[B.E.]]></given-names>
</name>
<name>
<surname><![CDATA[Almazán]]></surname>
<given-names><![CDATA[V.E.]]></given-names>
</name>
<name>
<surname><![CDATA[Mendoza]]></surname>
<given-names><![CDATA[M.C.]]></given-names>
</name>
</person-group>
<source><![CDATA[Gogia spiralis el eocrinoide de mayor antigüedad (Cámbrico temprano) de México]]></source>
<year>2004</year>
<volume>24</volume>
<numero>2</numero>
<issue>2</issue>
</nlm-citation>
</ref>
<ref id="B8">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Buitrón]]></surname>
<given-names><![CDATA[B.E.]]></given-names>
</name>
<name>
<surname><![CDATA[Vachard]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
<name>
<surname><![CDATA[Clausen]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
<name>
<surname><![CDATA[Gómez]]></surname>
<given-names><![CDATA[E.C.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Moluscos del Cámbrico (Hyolithida, Syssoiev, 1957) de San José de Gracia, Sonora, Noroeste de México]]></article-title>
<person-group person-group-type="editor">
<name>
<surname><![CDATA[Félix Pico]]></surname>
<given-names><![CDATA[E.F.]]></given-names>
</name>
<name>
<surname><![CDATA[Bertsch]]></surname>
<given-names><![CDATA[H.]]></given-names>
</name>
<name>
<surname><![CDATA[Campay]]></surname>
<given-names><![CDATA[R.C.]]></given-names>
</name>
</person-group>
<source><![CDATA[Reunión Internacional de Malacología]]></source>
<year>2011</year>
</nlm-citation>
</ref>
<ref id="B9">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Cirett]]></surname>
<given-names><![CDATA[G.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Aguilar]]></surname>
<given-names><![CDATA[R.F.]]></given-names>
</name>
</person-group>
<source><![CDATA[Características geológicas e hidrogeoquímicas del Valle de Ures, Sonora, México]]></source>
<year>1989</year>
<publisher-loc><![CDATA[Sonora, México ]]></publisher-loc>
<publisher-name><![CDATA[Universidad de Sonora]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B10">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Stratigraphy near Caborca, northwest Sonora, Mexico]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Cooper]]></surname>
<given-names><![CDATA[G.A.]]></given-names>
</name>
<name>
<surname><![CDATA[Arellano]]></surname>
<given-names><![CDATA[A.R.V.]]></given-names>
</name>
</person-group>
<source><![CDATA[Bulletin American Association Petroleum Geologists]]></source>
<year>1946</year>
<volume>30</volume>
<page-range>606-11</page-range></nlm-citation>
</ref>
<ref id="B11">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Cambrian Stratigraphy and Paleontology near Caborca, northwestern Sonora, México]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Cooper]]></surname>
<given-names><![CDATA[G.A.]]></given-names>
</name>
<name>
<surname><![CDATA[Arellano]]></surname>
<given-names><![CDATA[A.R.V.]]></given-names>
</name>
<name>
<surname><![CDATA[Johnson]]></surname>
<given-names><![CDATA[J.H.]]></given-names>
</name>
<name>
<surname><![CDATA[Okulitch]]></surname>
<given-names><![CDATA[V.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Stoyanow]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Lochman]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
</person-group>
<source><![CDATA[Smithsonian Miscellaneous Collections]]></source>
<year>1952</year>
<volume>119</volume>
<page-range>1-184</page-range></nlm-citation>
</ref>
<ref id="B12">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Cooper]]></surname>
<given-names><![CDATA[G.A.]]></given-names>
</name>
<name>
<surname><![CDATA[Arellano]]></surname>
<given-names><![CDATA[A.R.V.]]></given-names>
</name>
<name>
<surname><![CDATA[Johnson]]></surname>
<given-names><![CDATA[J.H.]]></given-names>
</name>
<name>
<surname><![CDATA[Okulitch]]></surname>
<given-names><![CDATA[V.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Stoyanow]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Lochman]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
</person-group>
<source><![CDATA[Geología y Paleontología de la región de Caborca, norponiente de Sonora]]></source>
<year>1956</year>
<publisher-name><![CDATA[Universidad Nacional Autónoma de México]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B13">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Cuen]]></surname>
<given-names><![CDATA[R.F.]]></given-names>
</name>
</person-group>
<source><![CDATA[Sobre la Estratigrafía y Paleontología del Cámbrico del área de San José de Gracia, Sonora central]]></source>
<year>2012</year>
<publisher-loc><![CDATA[Sonora, México ]]></publisher-loc>
<publisher-name><![CDATA[Universidad de Sonora]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B14">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Faunas marinas de invertebrados del Cámbrico temprano y medio en la parte central del estado de Sonora, México]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Cuen]]></surname>
<given-names><![CDATA[R.F.]]></given-names>
</name>
<name>
<surname><![CDATA[Almazán-Vázquez]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Montijo]]></surname>
<given-names><![CDATA[G.A.]]></given-names>
</name>
<name>
<surname><![CDATA[Minjárez]]></surname>
<given-names><![CDATA[S.I.]]></given-names>
</name>
<name>
<surname><![CDATA[Grijalva]]></surname>
<given-names><![CDATA[N.F.]]></given-names>
</name>
<name>
<surname><![CDATA[Monreal]]></surname>
<given-names><![CDATA[S.R.]]></given-names>
</name>
<name>
<surname><![CDATA[Schwennicke]]></surname>
<given-names><![CDATA[T.]]></given-names>
</name>
<name>
<surname><![CDATA[Ochoa]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
</person-group>
<source><![CDATA[Unión Geofísica Mexicana]]></source>
<year>2009</year>
<volume>29</volume>
<numero>1</numero>
<issue>1</issue>
</nlm-citation>
</ref>
<ref id="B15">
<nlm-citation citation-type="confpro">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Cuen]]></surname>
<given-names><![CDATA[R.F.]]></given-names>
</name>
<name>
<surname><![CDATA[Montijo]]></surname>
<given-names><![CDATA[G.A.]]></given-names>
</name>
<name>
<surname><![CDATA[Minjárez]]></surname>
<given-names><![CDATA[S.I.]]></given-names>
</name>
<name>
<surname><![CDATA[De la O]]></surname>
<given-names><![CDATA[V. M.]]></given-names>
</name>
<name>
<surname><![CDATA[Buitrón]]></surname>
<given-names><![CDATA[S.B.]]></given-names>
</name>
<name>
<surname><![CDATA[Sundberg]]></surname>
<given-names><![CDATA[F.]]></given-names>
</name>
</person-group>
<source><![CDATA[La biota del Cámbrico de San José de Gracia, Sonora: Consideraciones bioestratigráficas, sistemáticas y paleogeográficas]]></source>
<year>2012</year>
<conf-name><![CDATA[ XXXVSemana Cultural]]></conf-name>
<conf-loc> </conf-loc>
</nlm-citation>
</ref>
<ref id="B16">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Chancelloriia Walcott, 1920 y Reticulosa Reid, 1958 del Cámbrico medio de San José de Gracia, Sonora, México]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Cuen]]></surname>
<given-names><![CDATA[R.F.]]></given-names>
</name>
<name>
<surname><![CDATA[Beresi]]></surname>
<given-names><![CDATA[M.S.]]></given-names>
</name>
<name>
<surname><![CDATA[Montijo]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Buitrón]]></surname>
<given-names><![CDATA[B.E.]]></given-names>
</name>
<name>
<surname><![CDATA[Minjárez]]></surname>
<given-names><![CDATA[I.]]></given-names>
</name>
<name>
<surname><![CDATA[De la O]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Palafox]]></surname>
<given-names><![CDATA[J.J.]]></given-names>
</name>
</person-group>
<source><![CDATA[Boletín de la Sociedad Geológica Mexicana]]></source>
<year>2013</year>
<volume>65</volume>
<page-range>581-90</page-range></nlm-citation>
</ref>
<ref id="B17">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Folk]]></surname>
<given-names><![CDATA[R.L.]]></given-names>
</name>
</person-group>
<source><![CDATA[Petrology of sedimentary rocks]]></source>
<year>1965</year>
<publisher-loc><![CDATA[Austin, Texas ]]></publisher-loc>
<publisher-name><![CDATA[Hemphill Publishing Company]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B18">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Haldeman]]></surname>
<given-names><![CDATA[S.S.]]></given-names>
</name>
</person-group>
<source><![CDATA[Supplement to number one of a "Monograph of the Limnidae, or freshwater univalve shells of North America," containing descriptions of apparently new animals in different classes, and the names and characters of the subgenera in Paludina and Anculosa]]></source>
<year>1840</year>
<publisher-loc><![CDATA[Philadelphia ]]></publisher-loc>
</nlm-citation>
</ref>
<ref id="B19">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Huerta-Ruiz]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
</person-group>
<source><![CDATA[Moluscos del Cámbrico (Hyolithida, Syssoiv, 1957) de San José de Gracia, Sonora. Consideraciones bioestratigráficas, Paleoecológicas y Paleogeográficas]]></source>
<year>2011</year>
<publisher-loc><![CDATA[México ]]></publisher-loc>
<publisher-name><![CDATA[Universidad Nacional Autónoma de México]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B20">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[New Cambrian trilobite genera from northwest Sonora, Mexico]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Lochman]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
</person-group>
<source><![CDATA[Journal of Paleontology]]></source>
<year>1948</year>
<volume>22</volume>
<page-range>451-64</page-range></nlm-citation>
</ref>
<ref id="B21">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[The Cambrian succession of central Sonora: Tectonic implications (abstract)]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Maytorena-Silva]]></surname>
<given-names><![CDATA[J.F.]]></given-names>
</name>
<name>
<surname><![CDATA[Esparza-Yañez]]></surname>
<given-names><![CDATA[F.A.]]></given-names>
</name>
</person-group>
<source><![CDATA[Geological Society of America]]></source>
<year>1990</year>
<volume>22</volume>
<numero>3</numero>
<issue>3</issue>
</nlm-citation>
</ref>
<ref id="B22">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[First report of Gogia (Eocrinoidea - Echinodermata) from the Early - Middle Cambrian of Sonora (México), with biostratigraphical and palaeoecological comments]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Nardin]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Almazán-Vázquez]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Buitrón-Sánchez]]></surname>
<given-names><![CDATA[B.E.]]></given-names>
</name>
</person-group>
<source><![CDATA[Geobios]]></source>
<year>2009</year>
<volume>42</volume>
<page-range>233-42</page-range></nlm-citation>
</ref>
<ref id="B23">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Palmer]]></surname>
<given-names><![CDATA[A.R.]]></given-names>
</name>
<name>
<surname><![CDATA[Halley]]></surname>
<given-names><![CDATA[R.B.]]></given-names>
</name>
</person-group>
<source><![CDATA[Physical stratigraphy and trilobite biostratigraphy of the Carrara Formation (Lower and Middle Cambrian) in the southern Great Basin]]></source>
<year>1979</year>
</nlm-citation>
</ref>
<ref id="B24">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Middle Cambrian Eocrinoids from Western North America]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Robison]]></surname>
<given-names><![CDATA[R.A.]]></given-names>
</name>
</person-group>
<source><![CDATA[Journal of Paleontology]]></source>
<year>1965</year>
<volume>39</volume>
<page-range>355-64</page-range></nlm-citation>
</ref>
<ref id="B25">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Condiciones paleoambientales de depósito de las formaciones cámbricas del área de Caborca, Sonora]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Rivera-Carranco]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<source><![CDATA[Revista del Instituto de Geología]]></source>
<year>1988</year>
<volume>07</volume>
<page-range>22-7</page-range><publisher-name><![CDATA[Universidad Nacional Autónoma de México]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B26">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Seilacher]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Biogenic Sedimentary Structures]]></article-title>
<person-group person-group-type="editor">
<name>
<surname><![CDATA[Imbrie]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Newell]]></surname>
<given-names><![CDATA[N.]]></given-names>
</name>
</person-group>
<source><![CDATA[Approaches to Paleoecology]]></source>
<year>1964</year>
<page-range>296-316</page-range><publisher-loc><![CDATA[New York ]]></publisher-loc>
<publisher-name><![CDATA[Wiley]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B27">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Stewart]]></surname>
<given-names><![CDATA[J.H.]]></given-names>
</name>
<name>
<surname><![CDATA[McMenamin]]></surname>
<given-names><![CDATA[M.A.]]></given-names>
</name>
<name>
<surname><![CDATA[Morales-Ramírez]]></surname>
<given-names><![CDATA[J.M.]]></given-names>
</name>
</person-group>
<source><![CDATA[Upper Proterozoic and Cambrian Rocks in the Caborca Region, Sonora, Mexico - Physical Stratigraphy, Biostratigraphy, Paleocurrent Studies, and Regional Relations]]></source>
<year>1984</year>
</nlm-citation>
</ref>
<ref id="B28">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Neoproterozoic and Cambrian strata of Sonora, México. Rodinian Super continent to Laurentian Cordilleran Margin]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Stewart]]></surname>
<given-names><![CDATA[J.H.]]></given-names>
</name>
<name>
<surname><![CDATA[Amaya-Martinez]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Palmer]]></surname>
<given-names><![CDATA[A.R.]]></given-names>
</name>
</person-group>
<source><![CDATA[Geological Society of America]]></source>
<year>2002</year>
<volume>36</volume>
<page-range>9-15</page-range></nlm-citation>
</ref>
<ref id="B29">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Sundberg]]></surname>
<given-names><![CDATA[F.A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Delamaran biostratigraphy and Lithostratigraphy of the southern Nevada]]></article-title>
<person-group person-group-type="editor">
<name>
<surname><![CDATA[Hollingsworth]]></surname>
<given-names><![CDATA[J.S.]]></given-names>
</name>
<name>
<surname><![CDATA[Sundberg]]></surname>
<given-names><![CDATA[F.A.]]></given-names>
</name>
<name>
<surname><![CDATA[Foster]]></surname>
<given-names><![CDATA[J.R.]]></given-names>
</name>
</person-group>
<source><![CDATA[Museum of Northern Arizona, Bulletin]]></source>
<year>2011</year>
<volume>67</volume>
<page-range>174-85</page-range></nlm-citation>
</ref>
<ref id="B30">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Early and Mid Cambrian trilobites from the outer-shelf deposits of Nevada and California, USA]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Sundberg]]></surname>
<given-names><![CDATA[F.A.]]></given-names>
</name>
<name>
<surname><![CDATA[McCollum]]></surname>
<given-names><![CDATA[L.B.]]></given-names>
</name>
</person-group>
<source><![CDATA[Palaeontology]]></source>
<year>2003</year>
<volume>46</volume>
<page-range>945-86</page-range></nlm-citation>
</ref>
<ref id="B31">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Cambrian geology and Paleontology IV: 06, Middle Cambrian Spongiae]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Walcott]]></surname>
<given-names><![CDATA[C.D.]]></given-names>
</name>
</person-group>
<source><![CDATA[Smithsonian Miscellaneous Collections]]></source>
<year>1920</year>
<volume>67</volume>
<page-range>261-364</page-range></nlm-citation>
</ref>
<ref id="B32">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Wilson]]></surname>
<given-names><![CDATA[J.L.]]></given-names>
</name>
</person-group>
<source><![CDATA[Carbonate facies in geologic history]]></source>
<year>1975</year>
<publisher-name><![CDATA[Springer]]></publisher-name>
</nlm-citation>
</ref>
</ref-list>
</back>
</article>
