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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. -
A New Species of Gaudryceras (Ammonoidea, Gaudryceratidae) from the Lowest Maastrichtian of Hokkaido, Japan and Its Biostratigraphic Implications
Paleontological Research, vol. 17, no. 1, pp. 47–57, April 1, 2013 © by the Palaeontological Society of Japan doi:10.2517/1342-8144-17.1.47 A new species of Gaudryceras (Ammonoidea, Gaudryceratidae) from the lowest Maastrichtian of Hokkaido, Japan and its biostratigraphic implications 1 2 YASUNARI SHIGETA AND TOMOHIRO NISHIMURA 1Department of Geology and Paleontology, National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba, Ibaraki 305-0005, Japan (e-mail: [email protected]) 2Hobetsu Museum, 80-6, Hobetsu, Mukawa, Hokkaido 054-0211, Japan Received May 11, 2012; Revised manuscript accepted August 12, 2012 Abstract. Gaudryceras hobetsense sp. nov. is described from the Nostoceras hetonaiense Zone (= lowest Maastrichtian) of the Hobetsu area, south-central Hokkaido, Northern Japan. Its shell is characterized by fine lirae on early whorls, distant rounded or flat-topped, narrow band-like ribs on middle and later whorls, and frequent collar-like ribs on later whorls. The occurrence of this new species strongly suggests the presence of lowest Maastrichtian strata in southern Alaska, and sheds light on the age delineation of the chronologically poorly defined beds in northern and eastern Hokkaido. Key words: ammonoid, Cretaceous, Gaudryceras, Hobetsu, Hokkaido, Maastrichtian Introduction age (Shigeta et al., 2012). Because of the successive occurrence of several species and their restricted strati- The genus Gaudryceras de Grossouvre, 1894 is char- graphic ranges, Gaudryceras is an ideal ammonoid for acterized by an evolute shell with a wide, shallow umbi- precise biostratigraphic correlation of Maastrichtian licus, rounded venter and various ribbing styles. strata in the North Pacific realm. Although species of the genus ranging in age from late The biostratigraphic zonation scheme established for Albian to Maastrichtian are known worldwide (Kennedy the lowest Maastrichtian of Japan is based mainly on and Klinger, 1979; Hoffmann, 2010), their typical occur- ammonoids and inoceramid bivalves from the Hakobuchi rence is in the Tethyan and Indo-Pacific realms. -
GSSP) for the Base of the Cenomanian Stage, Mont Risou, Hautes-Alpes, France
21 by W.J. Kennedy1, A.S. Gale2, J.A. Lees3, and M. Caron4 The Global Boundary Stratotype Section and Point (GSSP) for the base of the Cenomanian Stage, Mont Risou, Hautes-Alpes, France 1 Oxford University Museum of Natural History, Parks Road, Oxford OX1 3PW, U.K. 2 Department of Palaeontology, The Natural History Museum, Cromwell Road, London SW7 5BP, U.K. and School of Earth and Environ- mental Sciences, University of Greenwich, Chatham Maritime Campus, Chatham, Kent ME4 4AW, U.K. 3 Research School of Geological and Geophysical Sciences, Birkbeck College and University College London, Gower Street, London WC1E 6BT, U.K. 4 Institut de Géologie, Université de Fribourg, CH-1700 Fribourg, Switzerland. Following the unanimous recommendation of the Inter- Grès Vert Supérieur etc., and taking the name from Touraine national Commission on Stratigraphy, the Global (Roman Turonia). Five years later, he realized that two distinct ammonite and rudist faunas were present, and he restricted the term boundary Stratotype Section and Point (GSSP) for the Turonian to beds corresponding to his third zone of rudists, yielding base of the Cenomanian Stage is defined at a level 36 “Ammonites lewesiensis, peramplus, Vielbancii, Woolgari, Fleuri- metres below the top of the Marnes Bleues Formation, a ausianus, Deverianus etc.”, “le plus beau type côtier étant très prononcé dans toute la Touraine, et nous donnerons à la partie level that corresponds to the the first appearance of the inférieure le nom d’étage Cénomanien, le Mans (Cenomanum), en planktonic foraminiferan Rotalipora globotruncanoides montrant à la fois le type sous-marin” (d'Orbigny, 1848–1851, p. -
Le Mans, France
High-resolution biostratigraphy and chemostratigraphy of the Cenomanian stratotype area (Le Mans, France) Delphine Desmares, Marc Testé, Bérengère Broche, Maxime Tremblin, Silvia Gardin, Loïc Villier, Edwige Masure, Danièle Grosheny, Nicolas Morel, Patrice Raboeuf To cite this version: Delphine Desmares, Marc Testé, Bérengère Broche, Maxime Tremblin, Silvia Gardin, et al.. High- resolution biostratigraphy and chemostratigraphy of the Cenomanian stratotype area (Le Mans, France). Cretaceous Research, Elsevier, 2020, 10.1016/j.cretres.2019.104198. hal-02328773 HAL Id: hal-02328773 https://hal.archives-ouvertes.fr/hal-02328773 Submitted on 23 Oct 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Journal Pre-proof High-resolution biostratigraphy and chemostratigraphy of the Cenomanian stratotype area (Le Mans, France) Delphine Desmares, Marc Testé, Bérengère Broche, Maxime Tremblin, Silvia Gardin, Loïc Villier, Edwige Masure, Danièle Grosheny, Nicolas Morel, Patrice Raboeuf PII: S0195-6671(19)30086-2 DOI: https://doi.org/10.1016/j.cretres.2019.104198 Reference: YCRES 104198 To appear in: Cretaceous Research Received Date: 1 March 2019 Revised Date: 12 July 2019 Accepted Date: 31 July 2019 Please cite this article as: Desmares, D., Testé, M., Broche, B., Tremblin, M., Gardin, S., Villier, L., Masure, E., Grosheny, D., Morel, N., Raboeuf, P., High-resolution biostratigraphy and chemostratigraphy of the Cenomanian stratotype area (Le Mans, France), Cretaceous Research, https:// doi.org/10.1016/j.cretres.2019.104198. -
Towards a Phylogenetic Classification of the Cretaceous Ammonites V
N.Jb. Geo\. Palaont. Abh. Stuttgart, Januar 1997 Towards a phylogenetic classification of the Cretaceous ammonites V. Euomphaloceratidae By M. R. Cooper, Durban With 5 figures in the text COOPER, M. R. (1997): Towards a phylogenetic classification of the Cretaceous ammo nites. V. Euomphaloceratidae. - N. Jb. Geo\. Palaont., Abh., 203: 1-21; Stuttgart. Abstract: Phylogenetic analysis of Euomphaloceratinae COOPER, 1978, a group within highly diversified and heterogeneous Acanthocerataceae, indicates a fundamental dichotomy which suggests promotion of this taxon to family rank with recognition of two subfamilies. Nominate Euomphaloceratinae comprise E. (Euomphaloceras), E. (Kanabiceras), Burroceras, Paraburroceras, P. (Pseudaspidoceras), P. (Ampakabites), and Morrowites, and Romaniceratinae subfam. nov. is made up of Schindewo/fites, Kameruno ceras, Codazziceras, Proromaniceras (Proromaniceras), P. (Obiraceras), Neomphaloceras, Yubariceras and Romaniceras (?with Shuparoceras as a subgenus). Zusammenfassung: Die phylogenetische Analyse der Euomphaloceratinae COOPER, 1978, einer Gruppe der hoch diversifizierten und heterogenen Acanthocerataceae, weist auf eine fundamentale Dichotomie innerhalb der Unterfamilie hin. Der Gruppe wird daher Familienrang verliehen und zwei Unterfamilien abgegrenzt. Die Nominat-Unter familie Euomphaloceratinae umfaBt E. (Euomphaloceras), E. (Kanabiceras), Burroceras, Paraburroceras, P. (Pseudaspidoceras), P. (Ampakabites) und Morrowites. Zur zweiten Unterfamilie Romaniceratinae subfam. nov. gehiiren Schindewo/fites, -
Phylogeny, Diversity, and Ecology of the Ammonoid Superfamily Acanthoceratoidea Through the Cenomanian and Turonian
PHYLOGENY, DIVERSITY, AND ECOLOGY OF THE AMMONOID SUPERFAMILY ACANTHOCERATOIDEA THROUGH THE CENOMANIAN AND TURONIAN DAVID A.A. MERTZ A Thesis Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 2017 Committee: Margaret Yacobucci, Advisor Andrew Gregory Keith Mann © 2017 David Mertz All Rights Reserved iii ABSTRACT Margaret Yacobucci Both increased extinction and decreased origination, caused by rising oceanic anoxia and decreased provincialism, respectively, have been proposed as the cause of the Cenomanian Turonian (C/T) extinction event for ammonoids. Conflicting evidence exists for whether diversity actually dropped across the C/T. This study used the ammonoid superfamily Acanthoceratoidea as a proxy for ammonoids as a whole, particularly focusing on genera found in the Western Interior Seaway (WIS) of North America, including Texas. Ultimately, this study set out to determine 1) whether standing diversity decreased across the C/T boundary in the WIS, 2) whether decreased speciation or increased extinction in ammonoids led to a drop in diversity in the C/T extinction event, 3) how ecology of acanthoceratoid genera changed in relation to the C/T extinction event, and 4) whether these ecological changes indicate rising anoxia as the cause of the extinction. In answering these questions, three phylogenetic analyses were run that recovered the families Acanthoceratidae, Collignoniceratidae, and Vascoceratidae. Pseudotissotiidae was not recovered at all, while Coilopoceratidae was recovered but reclassified as a subfamily of Vascoceratidae. Seven genera were reclassified into new families and one genus into a new subfamily. After calibrating the trees with stratigraphy, I was able to determine that standing diversity dropped modestly across the C/T boundary and the Early/Middle Turonian boundary. -
Mid-Cretaceous Ammonite Sequence for Western New Mexico Iv
iii Contents ABSTRACT 5 Genus Morrowites Cobban and Hook, n. gen. 9 Morrowites wingi (Morrow) 9 INTRODUCTION 5 M. depressus (Powell) 11 COMPOSITION OF MOLLUSCAN FAUNA 5 M. subdepressus Cobban and Hook, n. sp. 11 OCCURRENCE AND PRESERVATION OF FOSSILS 6 M. cf. M. dixeyi (Reyment) 12 STRATIGRAPHIC POSITION OF FOSSILS 6 Subfamily Euomphaloceratinae Cooper 13 COLLECTION LOCALITIES 7 Genus Kamerunoceras Reyment 13 Kamerunoceras turoniense (d'Orbigny) 13 FAMILY VASCOCERATIDAE H. Douvillé 14 SYSTEMATIC PALEONTOLOGY 7 Subfamily Vascoceratinae H. Douvillé 14 FAMILY BACULITIDAE GILL 7 Genus Neoptychites Kossmat 14 Genus Baculites Lamarck 7 Neoptychites cephalotus (Courtiller) 14 Baculites yokoyamai Tokunaga and Shimizu 7 Genus Fagesia Pervinquière 15 FAMILY MUNIERICERATIDAE WRIGHT 7 Fagesia superstes (Kossmat) 16 Genus Tragodesmoceras Spath 7 FAMILY C OLLIGNONICERATIDAE WRIGHT AND WRIGHT 16 Tragodesmoceras socorroense Cobban and Hook 7 Subfamily Barroisiceratinae Basse 16 FAMILY PLACENTICERATIDAE HYATT 8 Genus Cibolaites Cobban and Hook, n. gen. 16 Genus Placenticeras Spath 8 Cibolaites molenaari Cobban and Hook, n. sp. 16 Placenticeras cumminsi Cragin 8 REFERENCES 18 FAMILY ACANTHOCERATIDAE DE GROSSOUVRE 8 Subfamily Mammitinae Hyatt 8 Genus Mammites PLATES 1-14 21 Laube and Bruder 8 INDEX 50 Mammites nodosoides (Schluter) 8 TABLE 1—Mid-Cretaceous ammonite sequence for western New Mexico iv FIGURES 1—Location of study area 5 9—Histogram of size and body chambers of Neoptychites 2—External sutures of Mammites nodosoides (Schluter) 9 3— cephalotus (Courtiller) 14 Whorl sections of Morrowites wingi (Morrow) 10 4—External 10—Scatter diagram of breadth to diameter ratio of Neop- suture of Morrowites wingi (Morrow) 10 5—Whorl section and tychites 14 suture of Morrowites depressus 11—External sutures of Neoptychites cephalotus (Cour-tiller) 15 (Powell) 11 12—External suture of Fagesia superstes (Kossmat) 16 13— 6—External sutures of Morrowites subdepressus Cobban and Histogram of size of body chambers of Cibolaites molenaari Hook, n. -
Palaeontology and Biostratigraphy of the Lower Cretaceous Qihulin
Dissertation Submitted to the Combined Faculties for the Natural Sciences and for Mathematics of the Ruperto-Carola University of Heidelberg, Germany for the degree of Doctor of Natural Sciences presented by Master of Science: Gang Li Born in: Heilongjiang, China Oral examination: 30 November 2001 Gedruckt mit Unterstützung des Deutschen Akademischen Austauschdienstes (Printed with the support of German Academic Exchange Service) Palaeontology and biostratigraphy of the Lower Cretaceous Qihulin Formation in eastern Heilongjiang, northeastern China Referees: Prof. Dr. Peter Bengtson Prof. Pei-ji Chen This manuscript is produced only for examination as a doctoral dissertation and is not intended as a permanent scientific record. It is therefore not a publication in the sense of the International Code of Zoological Nomenclature. Abstract The purpose of the study was to provide conclusive evidence for a chronostratigraphical assignment of the Qihulin Formation of the Longzhaogou Group exposed in Mishan and Hulin counties of eastern Heilongjiang, northeastern China. To develop an integrated view of the formation, all collected fossil groups, i.e. the macrofossils (ammonites and bivalves) and microfossils (agglutinated foraminifers and radiolarians) have been studied. The low-diversity ammonite fauna consists of Pseudohaploceras Hyatt, 1900, and Eogaudryceras Spath, 1927, which indicate a Barremian–Aptian age. The bivalve fauna consists of eight genera and 16 species. The occurrence of Thracia rotundata (J. de C: Sowerby) suggests an Aptian age. The agglutinated foraminifers comprise ten genera and 16 species, including common Lower Cretaceous species such as Ammodiscus rotalarius Loeblich & Tappan, 1949, Cribrostomoides? nonioninoides (Reuss, 1836), Haplophragmoides concavus (Chapman, 1892), Trochommina depressa Lozo, 1944. The radiolarians comprise ten genera and 17 species, where Novixitus sp., Xitus cf. -
Bulletin of the British Museum (Natural History)
Origin, evolution and systematics of the dwarf Acanthoceratid Protacanthoceras Spath, 1923 (Cretaceous Ammonoidea) C. W. Wright Old Rectory, Seaborough, Beaminster, Dorset DT8 3QY W. J. Kennedy Geological Collections, University Museum, Parks Road, Oxford OX1 3PW Contents Synopsis ............. 65 Introduction ............. 66 Evolutionary origins ........... 66 Dimorphism ............. 67 Localities ............. 67 Stratigraphy ............. 68 Systematic descriptions ........... 68 Family Acanthoceratidae Hyatt ......... 68 Genus Protacanthoceras Spath ......... 68 Protacanthoceras tuberculatum Thomel ... .71 Protacanthoceras tuberculatum tuberculatum Thomel .. .71 Protacanthoceras tuberculatum Thomel mite subsp. nov. .... 74 Protacanthoceras tuberculatum Thomel devonense subsp. nov. ... 76 Protacanthoceras tuberculatum Thomel cyclopeum subsp. nov. ... 80 Protacanthoceras arkelli sp. nov. ........ 82 Protacanthoceras arkelli arkelli subsp. nov. ...... 84 Protacanthoceras arkelli verrucosum subsp. nov. ..... 86 Protacanthoceras tegulicium sp. nov. ........ 88 Protacanthoceras asgeirri sp. nov. ........ 90 Protacanthoceras bunburianum (Sharpe) ....... 91 Protacanthoceras proteus sp. nov. ........ 95 Protacanthoceras proteus proteus subsp. nov. ...... 95 Protacanthoceras proteus baylissi subsp. nov. ...... 96 Protacanthoceras imperatoris sp. nov. ....... 97 Other species previously referred to Protacanthoceras ...... 99 'Acanthoceras' cuspidum Stephenson ....... 99 ' Acanthoceras' aff. cuspidum Stephenson . .100 Ammonites tropicus Stoliczka -
The Gaudryceratid Ammonoids from the Upper Cretaceous of the James Ross Basin, Antarctica
The gaudryceratid ammonoids from the Upper Cretaceous of the James Ross Basin, Antarctica MARÍA E. RAFFI, EDUARDO B. OLIVERO, and FLORENCIA N. MILANESE Raffi, M.E., Olivero, E.B., and Milanese, F.N. 2019. The gaudryceratid ammonoids from the Upper Cretaceous of the James Ross Basin, Antarctica. Acta Palaeontologica Polonica 64 (3): 523–542. We describe new material of the subfamily Gaudryceratinae in Antarctica, including five new species: Gaudryceras submurdochi Raffi and Olivero sp. nov., Anagaudryceras calabozoi Raffi and Olivero sp. nov., Anagaudryceras subcom- pressum Raffi and Olivero sp. nov., Anagaudryceras sanctuarium Raffi and Olivero sp. nov., and Zelandites pujatoi Raffi and Olivero sp. nov., recorded in Santonian to Maastrichtian deposits of the James Ross Basin. The early to mid-Campan- ian A. calabozoi Raffi and Olivero sp. nov. exhibits a clear dimorphism, expressed by marked differences in the ornament of the adult body chamber. Contrary to the scarcity of representative members of the subfamily Gaudryceratinae in the Upper Cretaceous of other localities in the Southern Hemisphere, the Antarctic record reveals high abundance and di- versity of 15 species and three genera in total. This highly diversified record of gaudryceratins is only comparable with the Santonian–Maastrichtian Gaudryceratinae of Hokkaido, Japan and Sakhalin, Russia, which yields a large number of species of Anagaudryceras, Gaudryceras, and Zelandites. The reasons for a similar, highly diversified record of the Gaudryceratinae in these distant and geographically nearly antipodal regions are not clear, but we argue that they prob- ably reflect a similar paleoecological control. Key words: Ammonoidea, Phylloceratida, Gaudryceratinae, Lytoceratoidea, Cretaceous, Antarctica. María E. -
131. a Note on the Japanese Ammonites Belonging to the Caudryceratidae*
666 [Vol. 18, 131. A Note on the Japanese Ammonites Belonging to the Caudryceratidae*. By Taturo MATUMOTO. (Comm. by T. KATO,M.I.A., Dec. 12, 1942.) The Japanese fossils of the Gaudryceratidae, one of the important families of Cretaceous Ammonoidea, have been studied by H. Yabe and other Japanese paleontologists. I also had the opportunity of studying the material in connection with the biostratigraphic investi- gation on the Cretaceous deposits of Hokkaido and Karahuto. The following is a short note on the result of my study.' The numerous Japanese specimens so far examined are classified as follows. Family Gaydryceratidae. Genus Parajaubertella; Matumoto nov. P. kawakitana Matumoto nov. (genotype) Genus Anagaudryceras, Shimizu emend. A, sacya (Fortes) em. (genotype) A. sacya var. plicatocostata Matumoto MS. A. limatum (Yabe) A. yokoyamai (Yabe) A, ryugasense Matumoto MS. A. madraspatanum (Blanford) Genus Gaudryceras, Grossouvre em. G. denseplicatum (Jimbo) G. denseplicatum var. intermedia (Yabe) em. G. denseplicatum var. kawadai Matumoto MS. G. tenuiliratum Yabe em. G. tenuiliratum var. frequence Matumoto MS. G. tenuiliratum var. substriata Matumoto MS. G. tenuiliratum var. ornata Yabe G. striatum (limbo) (=? G, sachalinensis (Schmidt)) G. striatum var. paucistriata Matumoto MS. G. striatum var. picta Yabe G. striatum var. lata Matumoto MS. G. crassicostatum (Jimbo) G. subcostatum Matumoto MS. Genus Zelandites, Marshall em. Matumoto Z. odiensis (Kossmat) Z, odiensis var. lateumbilicata Matumoto MS. Z. mihoensis Matumoto Z. mihoensis var. capricornus Matumoto MS. Z. kawadai (limbo) em. Z. varuna (Forties) var. japonica Matumoto Z. sp. (n, sp. ?) A close investigation of the ontogenetic development enables us to elucidate the proper systematic position of species and genera. -
Codazziceras Ospinae (Karsten, 1858) from the Turonian (Upperᅢツᅡᅠcretaceous) of Colombia
Cretaceous Research 88 (2018) 392e398 Contents lists available at ScienceDirect Cretaceous Research journal homepage: www.elsevier.com/locate/CretRes Codazziceras ospinae (Karsten, 1858) from the Turonian (Upper Cretaceous) of Colombia * Pedro Patarroyo a, , Peter Bengtson b a Departamento de Geociencias, Universidad Nacional de Colombia, Cr. 30 N. 45-03, Bogota, Colombia b Institut für Geowissenschaften, Im Neuenheimer Feld 234, 69120 Heidelberg, Germany article info abstract Article history: The ammonite Codazziceras ospinae (Karsten, 1858) is described from sections in the Upper Magdalena Received 29 December 2016 Valley and San Francisco, south and north-west of Bogota, Colombia. Its co-occurrence with species of Received in revised form Hoplitoides von Koenen, 1898, and Coilopoceras Hyatt, 1903, places it stratigraphically in the lower to 30 March 2017 middle Turonian, in contrast to previous assignments to the upper Turonian to lower Coniacian. Three Accepted in revised form 2 April 2017 specimens come from the lower part of the Loma Gorda Formation (TuronianeConiacian) and one Available online 4 April 2017 specimen from the middle part of the La Frontera Formation (loweremiddle Turonian). The type species of the genus Codazziceras Etayo-Serna, 1979, is Lyelliceras scheibei Riedel, 1938, which Keywords: Codazziceras is a junior synonym of Ammonites Ospinae Karsten, 1858. If a new type species is to be selected, Turonian Codazziceras ospinae will be the obvious choice. Cretaceous © 2017 Elsevier Ltd. All rights reserved. Ammonites Colombia 1. Introduction formation, spanning the Turonian and Coniacian, as evidenced by ammonites and inoceramids (cf. Carvajal Gonzalez and Patarroyo, During field work with geology students of the Universidad 2007; Patarroyo, 2011).