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Stratigraphy and Paleontology of Mid-Cretaceous Rocks in Minnesota and Contiguous Areas
Stratigraphy and Paleontology of Mid-Cretaceous Rocks in Minnesota and Contiguous Areas GEOLOGICAL SURVEY PROFESSIONAL PAPER 1253 Stratigraphy and Paleontology of Mid-Cretaceous Rocks in Minnesota and Contiguous Areas By WILLIAM A. COBBAN and E. A. MEREWETHER Molluscan Fossil Record from the Northeastern Part of the Upper Cretaceous Seaway, Western Interior By WILLIAM A. COBBAN Lower Upper Cretaceous Strata in Minnesota and Adjacent Areas-Time-Stratigraphic Correlations. and Structural Attitudes By E. A. M EREWETHER GEOLOGICAL SURVEY PROFESSIONAL PAPER 1 2 53 UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1983 UNITED STATES DEPARTMENT OF THE INTERIOR JAMES G. WATT, Secretary GEOLOGICAL SURVEY Dallas L. Peck, Director Library of Congress Cataloging in Publication Data Cobban, William Aubrey, 1916 Stratigraphy and paleontology of mid-Cretaceous rocks in Minnesota and contiguous areas. (Geological Survey Professional Paper 1253) Bibliography: 52 p. Supt. of Docs. no.: I 19.16 A. Molluscan fossil record from the northeastern part of the Upper Cretaceous seaway, Western Interior by William A. Cobban. B. Lower Upper Cretaceous strata in Minnesota and adjacent areas-time-stratigraphic correlations and structural attitudes by E. A. Merewether. I. Mollusks, Fossil-Middle West. 2. Geology, Stratigraphic-Cretaceous. 3. Geology-Middle West. 4. Paleontology-Cretaceous. 5. Paleontology-Middle West. I. Merewether, E. A. (Edward Allen), 1930. II. Title. III. Series. QE687.C6 551.7'7'09776 81--607803 AACR2 For sale by the Distribution Branch, U.S. -
Palaeontology and Stratigraphy of the Inoceramid Species from the Mid-Turonian Through Upper Middle Coniacian in Japan
Acta Geologica Polonica, Vol. 48 (1998), No.4, pp. 435-482 Palaeontology and stratigraphy of the inoceramid species from the mid-Turonian through upper Middle Coniacian in Japan MASAYUKI NODAl & TATSURO MATSUMOT02 IFukagochi 5kumi, Oita 870-0881, Japan 2c/O Department of Earth & Planetary Science, Kyushu University 33, Fukuoka 812, Japan ABSTRACT: NODA, M. & MATSUMOTO, T. 1998. Palaeontology and stratigraphy of the inoceramid species from the mid-Turonian through upper Middle Coniacian in Japan. Acta Geologica Polonica, 48 (4),435-482. Warszawa. Upper Cretaceous strata are weIl exposed in many areas of Japan, although good exposures through the Turonian/Coniacian boundary are not common. This paper focuses on six areas in Hokkaido, Shikoku and Kyushu and documents the stratigraphical distributions of inoceramid species. These data are used to summarise the stratigraphical ranges of Turonian/Coniacian taxa in Japan. In part 1 of the paper, 17 species are described, with some biometric data and phylogenetic interpretation. These species are: Inoceramus (1noceramus) hobetsensis NAGAO & MATSUMOTO, I. (1.) teshioensis NAGAO & MATSUMOTO, 1. (1.) iburiensis NAGAO & MATSUMOTO, I. (1.) tenuistriatus NAGAO & MATSUMOTO, I. (1.) pedalionoides NAGAO & MATSUMOTO, I. (1.) lusatiae ANDERT, I. (1.) uwajimensis YEHARA, I. (Cremnoceramus) rotun datus FIEGE, I. (Cr.) ernsti HEINZ, I. (Cr.) deformis MEEK, I. (Cr.) lueckendorfensis TRaGER, I. (Platyceramus) tappuensis nom. nov., I. (Pl.) szaszi NODA & UCHIDA, I. (Volviceramus) koeneni MULLER, Mytiloides incertus (JI!VlBO), M. mytiloidiformis (TRaGER), and M. sublabiatus (MULLER). In part 2, the stratigraphical distribution and correlation of these species are discussed. INTRODUCTION boundary problem (MATSUMOTO & NODA 1985; NOD A 1992, 1996; NOD A & UCHIDA 1995). -
TREATISE ONLINE Number 48
TREATISE ONLINE Number 48 Part N, Revised, Volume 1, Chapter 31: Illustrated Glossary of the Bivalvia Joseph G. Carter, Peter J. Harries, Nikolaus Malchus, André F. Sartori, Laurie C. Anderson, Rüdiger Bieler, Arthur E. Bogan, Eugene V. Coan, John C. W. Cope, Simon M. Cragg, José R. García-March, Jørgen Hylleberg, Patricia Kelley, Karl Kleemann, Jiří Kříž, Christopher McRoberts, Paula M. Mikkelsen, John Pojeta, Jr., Peter W. Skelton, Ilya Tëmkin, Thomas Yancey, and Alexandra Zieritz 2012 Lawrence, Kansas, USA ISSN 2153-4012 (online) paleo.ku.edu/treatiseonline PART N, REVISED, VOLUME 1, CHAPTER 31: ILLUSTRATED GLOSSARY OF THE BIVALVIA JOSEPH G. CARTER,1 PETER J. HARRIES,2 NIKOLAUS MALCHUS,3 ANDRÉ F. SARTORI,4 LAURIE C. ANDERSON,5 RÜDIGER BIELER,6 ARTHUR E. BOGAN,7 EUGENE V. COAN,8 JOHN C. W. COPE,9 SIMON M. CRAgg,10 JOSÉ R. GARCÍA-MARCH,11 JØRGEN HYLLEBERG,12 PATRICIA KELLEY,13 KARL KLEEMAnn,14 JIřÍ KřÍž,15 CHRISTOPHER MCROBERTS,16 PAULA M. MIKKELSEN,17 JOHN POJETA, JR.,18 PETER W. SKELTON,19 ILYA TËMKIN,20 THOMAS YAncEY,21 and ALEXANDRA ZIERITZ22 [1University of North Carolina, Chapel Hill, USA, [email protected]; 2University of South Florida, Tampa, USA, [email protected], [email protected]; 3Institut Català de Paleontologia (ICP), Catalunya, Spain, [email protected], [email protected]; 4Field Museum of Natural History, Chicago, USA, [email protected]; 5South Dakota School of Mines and Technology, Rapid City, [email protected]; 6Field Museum of Natural History, Chicago, USA, [email protected]; 7North -
Correlation of Albian European and Tethyan Ammonite Zonations and the Boundaries of the Albian Stage and Substages: Some Comments
Correlation of Albian European and Tethyan ammonite zonations and the boundaries of the Albian Stage and substages: some comments Hugh G. Owen Owen, H.G. Correlation of Albian European and Tethyan ammonite zonations and the boundaries of the Albian Stage and substages: some comments. — Scripta Geol., Spec. Issue 3: 129-149, 5 figs., Lei• den, December 1999. H.G. Owen, Department of Palaeontology, The Natural History Museum, Cromwell Road, London SW7 5BD, England (UK). Key words: Early Cretaceous, Albian Stage, ammonite zonation, European and Tethyan faunal provinces Although the so-called 'standard' ammonite zonation of the Albian contains index species which occur in the Tethyan province, the scheme largely reflects the faunal succession in the European fau• nal province with its endemic sonneratiinid and hoplitinid faunal elements. Workers in the Tethyan province, stretching from South America in the west to Australia in the east, including southern Africa, Madagascar and India, face problems in the correlation of their successions with this so-called 'standard' scheme. There are other problems in that the succession of hoplitinid ammonites used in the biostratigraphy of European Albian sediments allows a far more detailed zonation to be made than in the case of some of the longer time-ranging Tethyan forms. This paper comments on propos• als made recently for the delimiting of the base of the Albian Stage, and the Middle and Upper Sub- stages, based on ammonite faunas. New information which affects the Albian ammonite zonation in the European faunal province and its correlation with the Tethyan province is discussed. The current hierarchical framework of zones and subzones used in the European faunal province may prove to be unsatisfactory in interprovincial correlation and particularly if the lower boundary of the Albian Stage was placed within the current Leymeriella tardefurcata ammonite Zone, instead of at its base. -
Biodiversità Ed Evoluzione
Allma Mater Studiiorum – Uniiversiità dii Bollogna DOTTORATO DI RICERCA IN BIODIVERSITÀ ED EVOLUZIONE Ciclo XXIII Settore/i scientifico-disciplinare/i di afferenza: BIO - 05 A MOLECULAR PHYLOGENY OF BIVALVE MOLLUSKS: ANCIENT RADIATIONS AND DIVERGENCES AS REVEALED BY MITOCHONDRIAL GENES Presentata da: Dr Federico Plazzi Coordinatore Dottorato Relatore Prof. Barbara Mantovani Dr Marco Passamonti Esame finale anno 2011 of all marine animals, the bivalve molluscs are the most perfectly adapted for life within soft substrata of sand and mud. Sir Charles Maurice Yonge INDEX p. 1..... FOREWORD p. 2..... Plan of the Thesis p. 3..... CHAPTER 1 – INTRODUCTION p. 3..... 1.1. BIVALVE MOLLUSKS: ZOOLOGY, PHYLOGENY, AND BEYOND p. 3..... The phylum Mollusca p. 4..... A survey of class Bivalvia p. 7..... The Opponobranchia: true ctenidia for a truly vexed issue p. 9..... The Autobranchia: between tenets and question marks p. 13..... Doubly Uniparental Inheritance p. 13..... The choice of the “right” molecular marker in bivalve phylogenetics p. 17..... 1.2. MOLECULAR EVOLUTION MODELS, MULTIGENE BAYESIAN ANALYSIS, AND PARTITION CHOICE p. 23..... CHAPTER 2 – TOWARDS A MOLECULAR PHYLOGENY OF MOLLUSKS: BIVALVES’ EARLY EVOLUTION AS REVEALED BY MITOCHONDRIAL GENES. p. 23..... 2.1. INTRODUCTION p. 28..... 2.2. MATERIALS AND METHODS p. 28..... Specimens’ collection and DNA extraction p. 30..... PCR amplification, cloning, and sequencing p. 30..... Sequence alignment p. 32..... Phylogenetic analyses p. 37..... Taxon sampling p. 39..... Dating p. 43..... 2.3. RESULTS p. 43..... Obtained sequences i p. 44..... Sequence analyses p. 45..... Taxon sampling p. 45..... Maximum Likelihood p. 47..... Bayesian Analyses p. 50..... Dating the tree p. -
Palaeontology of the Middle Turonian Limestones of the Nysa Kłodzka Graben
Palaeontology of the Middle Turonian limestones of the Nysa Kłodzka Graben... Geologos 18, 2 (2012): 83–109 doi: 10.2478/v10118-012-0007-z Palaeontology of the Middle Turonian limestones of the Nysa Kłodzka Graben (Sudetes, SW Poland): biostratigraphical and palaeogeographical implications Alina Chrząstek Institute of the Geological Sciences, Wrocław University, Maksa Borna 9, PL 50-204 Wrocław, Poland; e-mail: [email protected] Abstract The ammonites Lewesiceras peramplum Mantell and ?Lewesiceras sp. are reported from the Upper Cretaceous in the Nysa Kłodzka Graben; they date from the Middle Turonian and ?Coniacian, respectively. The Middle Turonian lime- stones of the Stara Bystrzyca quarry contain an abundant assemblage of inoceramids (Inoceramus cuvieri Sowerby and I. lamarcki Parkinson) and other bivalves, including oysters, as well as brachiopods and trace fossils. Micropalaeonto- logical data show the presence of foraminifers and siliceous sponge spiculae, bryozoans, ostracods and fragments of bivalves and gastropods. The Middle Turonian calcareous deposits belongs to the upper part of the Inoceramus lamarcki Zone (late Middle Turonian) and were deposited on a shallow, subtidal offshore shelf. They overlie the Middle Turo- nian Bystrzyca and Długopole Sandstones, which represent foreshore-shoreface delta deposits. The fossil assemblage suggests a moderate- to low-energy, normal-salinity environment with occasionally an oxygen deficit. Keywords: Middle Turonian, Sudetes, Nysa Kłodzka Graben, ammonites, inoceramids, biostratigraphy 1. Introduction Stara Bystrzyca quarry. It is, with its diameter of approx. 45 cm, probably the biggest ammo- Representatives of the ammonite genus nite ever found in Nysa Kłodzka Graben and Lewesiceras are most typical of the Middle-Late probably also in the Sudety Mountains (Fig. -
Annotated Catalogue of Marine Squamates (Reptilia) from the Upper Cretaceous of Northeastern Mexico
Netherlands Journal of Geosciences — Geologie en Mijnbouw | 84 - 3 | 195 - 205 | 2005 Annotated catalogue of marine squamates (Reptilia) from the Upper Cretaceous of northeastern Mexico M.-C. Buchy1-*, K.T. Smith2, E. Frey3, W. Stinnesbeck4, A.H. Gonzalez Gonzalez5, C. Ifrim4, J.G. Lopez-Oliva6 & H. Porras-Muzquiz7 1 Universitat Karlsruhe, Geologisches Institut, Postfach 6980, D-76128 Karlsruhe, Germany; current address: Geowissenschaftliche Abteilung, Staatliches Museum fur Naturkunde, Erbprinzenstrasse 13, D-76133 Karlsruhe, Germany. 2 Department of Geology and Geophysics, Yale University, P.O. Box 208109, New Haven, Connecticut 06520-8109, USA. 3 Geowissenschaftliche Abteilung, Staatliches Museum fur Naturkunde, Erbprinzenstrasse 13, D-76133 Karlsruhe, Germany. 4 Universitat Karlsruhe, Geologisches Institut, Postfach 6980, D-76128 Karlsruhe, Germany. 5 Museo del Desierto, Saltillo, Coahuila, Mexico. 6 Universidad Autonoma de Nuevo Leon, Facultad de Ciencias de la Tierra, Linares, Nuevo Leon, Mexico. 7 Museo Historico de Muzquiz, Muzquiz, Coahuila, Mexico. * Corresponding author. Email: [email protected] Manuscript received: November 2004; accepted: March 2005 Abstract Recent work in the Upper Cretaceous of northeastern Mexico has produced a diversity of vertebrate remains. For specimens referable to Squamata, both old and new, an annotated catalogue is here provided, wherein are summarised the geological context and morphological features of each specimen. All specimens appear to represent marine squamates, including an aigialosaur-like reptile preserving integumentary structures, several vertebrae possibly representing mosasauroids, the first Mexican mosasaur known from significant cranial material, an isolated mosasaur mandibular fragment, and the holotype of Amphekepubis johnsoni (considered to belong to Mosasaurus). These discoveries are auspicious and should deepen our understanding of palaeobiogeographic and evolutionary patterns. -
Abbreviation Kiel S. 2005, New and Little Known Gastropods from the Albian of the Mahajanga Basin, Northwestern Madagaskar
1 Reference (Explanations see mollusca-database.eu) Abbreviation Kiel S. 2005, New and little known gastropods from the Albian of the Mahajanga Basin, Northwestern Madagaskar. AF01 http://www.geowiss.uni-hamburg.de/i-geolo/Palaeontologie/ForschungImadagaskar.htm (11.03.2007, abstract) Bandel K. 2003, Cretaceous volutid Neogastropoda from the Western Desert of Egypt and their place within the noegastropoda AF02 (Mollusca). Mitt. Geol.-Paläont. Inst. Univ. Hamburg, Heft 87, p 73-98, 49 figs., Hamburg (abstract). www.geowiss.uni-hamburg.de/i-geolo/Palaeontologie/Forschung/publications.htm (29.10.2007) Kiel S. & Bandel K. 2003, New taxonomic data for the gastropod fauna of the Uzamba Formation (Santonian-Campanian, South AF03 Africa) based on newly collected material. Cretaceous research 24, p. 449-475, 10 figs., Elsevier (abstract). www.geowiss.uni-hamburg.de/i-geolo/Palaeontologie/Forschung/publications.htm (29.10.2007) Emberton K.C. 2002, Owengriffithsius , a new genus of cyclophorid land snails endemic to northern Madagascar. The Veliger 45 (3) : AF04 203-217. http://www.theveliger.org/index.html Emberton K.C. 2002, Ankoravaratra , a new genus of landsnails endemic to northern Madagascar (Cyclophoroidea: Maizaniidae?). AF05 The Veliger 45 (4) : 278-289. http://www.theveliger.org/volume45(4).html Blaison & Bourquin 1966, Révision des "Collotia sensu lato": un nouveau sous-genre "Tintanticeras". Ann. sci. univ. Besancon, 3ème AF06 série, geologie. fasc.2 :69-77 (Abstract). www.fossile.org/pages-web/bibliographie_consacree_au_ammon.htp (20.7.2005) Bensalah M., Adaci M., Mahboubi M. & Kazi-Tani O., 2005, Les sediments continentaux d'age tertiaire dans les Hautes Plaines AF07 Oranaises et le Tell Tlemcenien (Algerie occidentale). -
Synecology of an Unusual Late Cretaceous Inoceramid-Spondylid Association from Northern Italy (*)
Ann. Mus. civ. Rovereto Sez.: Arch., St., Sc. nat. Vol. 11 (1995) 327-338 1996 ANNIE V. DHONDT & IGINIO DIENI SYNECOLOGY OF AN UNUSUAL LATE CRETACEOUS INOCERAMID-SPONDYLID ASSOCIATION FROM NORTHERN ITALY (*) NNIE HONDT GINIO IENI Abstract - A V. D & I D - Synecology of an unusual Late Cretaceous inoceramid-spondylid association from Northern Italy. A large specimen of the Santonian inoceramid Cladoceramus undulatoplicatus (F. ROEMER) was found in the Scaglia Rossa Veneta formation at Passo del Brocon, Trento, N. Italy. Both valves of this inoceramid are covered with numerous iso-oriented specimens of Spondylus fimbriatus GOLDFUSS. The distribution of the spondylids is explained by the upright position of the living inoceramid specimen. Key words: Bivalvia, Inoceramidae, Spondylidae, Santonian, Northern Italy, Palaeoecology. NNIE HONDT GINIO IENI Riassunto - A V. D & I D - Sinecologia di una inconsueta associazione inoceramo-spondili nel Cretaceo superiore dell'Italia settentrionale. Nella Scaglia Rossa Veneta di età santoniana di Passo del Brocon (Trento) è stato rinvenuto un grande esemplare di Cladoceramus undulatoplicatus (F. ROEMER). Entrambe le valve di questo inoceramide sono rivestite di numerosi esemplari isorientati di Spondylus fimbriatus GOLDFUSS. La distribuzione degli spondilidi permette di ipotizzare per linoceramide una posizione di vita verticale. Parole chiave: Bivalvia, Inoceramidae, Spondylidae, Santoniano, Italia settentrionale, Paleoecologia. (*) This paper was presented at the Second International Congress on Palaeoecology (Nanjing, China, August 30 - September 3, 1991), the Proceedings of which have not been published. Work supported by the Italian M.U.R.S.T. (grants to I. Dieni). 327 INTRODUCTION When studying the ecology of organisms extinct to-day it is often difficult to understand their life habits. -
Bedrock Geology of Round Rock and Surrounding Areas, Williamson and Travis Counties, Texas
Bedrock Geology of Round Rock and Surrounding Areas, Williamson and Travis Counties, Texas Todd B. Housh Bedrock Geology of Round Rock and Surrounding Areas, Williamson and Travis Counties, Texas Todd B. Housh Copyright 2007 Todd B Housh, PhD, PG Round Rock, TX 78664 Cover photograph: The “Round Rock,” an erosional pedestal of Edward’s limestone that marked the low‐water crossing of Brushy Creek by the Chisholm Trail. 2 Table of Contents Introduction 5 Tectonic History 6 Previous Studies 8 Other Geologic Constraints 9 Stratigraphy 9 Comanche Series Fredericksburg Group Walnut Formation 10 Comanche Peak 10 Edwards 12 Kiamichi 13 Washita Group Georgetown 14 Del Rio 15 Buda 16 Gulf Series Woodbine Group Pepper 16 Eagle Ford Group 17 Austin Group 19 Taylor Group 21 Tertiary and Quaternary Systems Plio‐Pleistocene to Recent 22 Structure 23 Acknowledgements 27 Bibliography 28 Appendix 1. Compilation of sources of other geologic information. 34 Appendix 2. Localities of note to observe important geologic 40 features in the Round Rock Area. Appendix 3. Checklist of Cretaceous and Pleistocene fossils 45 3 4 Bedrock Geology of Round Rock and Surrounding Areas, Williamson and Travis Counties, Texas Todd B. Housh Introduction The purpose of this study was to produce a map of the bedrock geology of the city of Round Rock, Texas and its environs and to evaluate the geologic structure of the area. Most of the City of Round Rock lies within the Round Rock 7.5 minute quadrangle, Williamson County, Texas1, although parts of the city also lie within the Pflugerville West 7.5 minute quadrangle, Travis County, Texas2 and the Hutto 7.5 minute quadrangle, Williamson County, Texas3. -
Redalyc.Lamnoid Vertebrae from the Agua Nueva Formation (Upper
Revista Mexicana de Ciencias Geológicas ISSN: 1026-8774 [email protected] Universidad Nacional Autónoma de México México Blanco Piñon, Alberto; Shimada, Kenshu; González Barba, Gerardo Lamnoid vertebrae from the Agua Nueva Formation (Upper Cretaceous: Lower Turonian), northeastern Mexico Revista Mexicana de Ciencias Geológicas, vol. 22, núm. 1, 2005, pp. 19-23 Universidad Nacional Autónoma de México Querétaro, México Available in: http://www.redalyc.org/articulo.oa?id=57222102 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Revista Mexicana de Ciencias Geológicas,Lamnoid v. vertebrae 22, núm. from1, 2005, the Aguap. 19-23 Nueva Formation, NE Mexico 19 Lamnoid vertebrae from the Agua Nueva Formation (Upper Cretaceous: lower Turonian), northeastern Mexico Alberto Blanco-Piñón1,*, Kenshu Shimada2,3, and Gerardo González-Barba4 1 Centro de Investigaciones en Ciencias de la Tierra, Universidad Autónoma del Estado de Hidalgo, Carretera Pachuca-Tulancingo Km. 4.5. Pachuca, Hidalgo. Mexico. 2 Environmental Science Program and Department of Biological Sciences, DePaul University, 2325 North Clifton Avenue, Chicago, Illinois 60614, USA. 3 Sternberg Museum of Natural History, Fort Hays State University, Hays, Kansas 67601, USA 4 Departmento de Geología, Universidad Autónoma de Baja California Sur, Apartado.Postal 19B, 23080 La Paz, Baja California Sur, Mexico. * [email protected] ABSTRACT A partial vertebral series of a lamniform shark (Chondrichthyes: Elasmobranchii) occurred in the “Vallecillo fish Member” of the Agua Nueva Formation (Upper Cretaceous: Lower Turonian) at Vallecillo, Mexico. -
The Oldest Stratigraphic Record of the Late Cretaceous Shark Ptychodus Mortoni Agassiz, from Vallecillo, Nuevo León, Northeastern Mexico
Revista Mexicana de Ciencias Geológicas ISSN: 1026-8774 [email protected] Universidad Nacional Autónoma de México México Blanco Piñon, Alberto; Garibay Romero, Luis M.; Alvarado Ortega, Jesús The oldest stratigraphic record of the Late Cretaceous shark Ptychodus mortoni Agassiz, from Vallecillo, Nuevo León, northeastern Mexico Revista Mexicana de Ciencias Geológicas, vol. 24, núm. 1, 2007, pp. 25-30 Universidad Nacional Autónoma de México Querétaro, México Available in: http://www.redalyc.org/articulo.oa?id=57224103 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Revista Mexicana de Ciencias Geológicas, v. 24,The núm. oldest 1, 2007, record p. of 25-30 Ptychodus mortoni 25 The oldest stratigraphic record of the Late Cretaceous shark Ptychodus mortoni Agassiz, from Vallecillo, Nuevo León, northeastern Mexico Alberto Blanco-Piñón1,*, Luis M. Garibay-Romero2,3, and Jesús Alvarado-Ortega2 1 Centro de Investigaciones en Ciencias de la Tierra, Universidad Autónoma del Estado de Hidalgo, Apdo. Postal 1-288, Admón. 1, 42001 Pachuca, Hidalgo, Mexico.. 2 Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 México, D.F., Mexico. 3 Universidad Autónoma de Guerrero, Unidad Académica de Ciencias de la Tierra, Ex-Hacienda de San Juan Bautista, Taxco el Viejo, Guerrero. Mexico. * [email protected] ABSTRACT In this paper we report the oldest geologic world record of Ptychodus mortoni, from the Vallecillo Member (Agua Nueva Formation), at Vallecillo, Nuevo León, northeastern Mexico.