Part 1

BUREAU OF ECONOMIC GEOLOGY The University of Texas at Austin Austin, Texas 78712 John T. Lonsdale, Director

Guidebook 2

TEXAS FOSSILS: An Amateur Collector’s Handbook

By William H. Matthews III

November 1960 Second Printing, July 1963 Third Printing, August 1967 Fourth Printing, June 1971 Fifth Printing, November 1973 Sixth Printing, April 1976 Seventh Printing, November 1978 Eighth Printing, September 1981 Ninth Printing, August 1984

Contents

Page Introduction 1 What are fossils? 3 The study of fossils 4 Paleobotany 4 Invertebrate paleontology 4 Vertebrate paleontology 4 Micropaleontology 4 Preservation of fossils 5 Requirements of fossilization 5 Missing pages in the record 5 Different kinds of fossil preservation 7 Original soft parts of organisms 7 Original hard parts of organisms 7 Calcareous remains 10 Phosphatic remains 10 Siliceous remains 10 Chitinous remains 10 Altered hard parts of organisms 10 Carbonization 10 Petrifaction or permineralization 10 Replacement or mineralization 10 Replacement by calcareous material 11 Replacement by siliceous material 11 Replacement by iron compounds 11 Traces of organisms 11 Molds and casts 11 Tracks, trails, and burrows 14 Coprolites 14 Gastroliths 14 Pseudofossils 14 Dendrites 14 Slickensides 16 Concretions 16 Where and how to collect fossils 17 Collecting equipment 17 Where to look 19 How to collect 20 Cleaning and preparation of fossils 21 How fossils are named 21 The science of classification 21 The units of classification 22 Identification of fossils 23 Use of identification keys 23 Identification key to main types of invertebrate fossils 26 List of Texas colleges offering geology courses 27 Cataloging the collection 31 How fossils are used 31 Geologic history 33 Geologic column and time scale 33 The geology of Texas 34 Physiography 35 Trans-Pecos region 35 Texas Plains 35 High Plains 35 North-central Plains 37 Edwards Plateau 37 Grand Prairie 37 Llano uplift 37 Gulf Coastal Plain 37 Geology 37 Precambrian rocks 40 Paleozoic rocks 40 Cambrian 40 Ordovician 40 Silurian 40 Devonian 40 Mississippian 41 Pennsylvanian 41 Permian 41 Mesozoic rocks 42 Triassic 42 Jurassic 42 Cretaceous 42 Cenozoic rocks 43 Tertiary 43 Quaternary 43 Main types of fossils 44 Plant fossils 44 Classification of the plant kingdom 44 Division Thallophyta 44 Division Bryophyta 44 Division Tracheophyta 44 Animal fossils 48 Phylum Protozoa 48 Class Sarcodina 48 Order Foraminifera 48 Order Radiolaria 48 Phylum Porifera 49 Phylum Coelenterata 49 Class Anthozoa 49 Subclass Zoantharia 50 Order Rugosa 50 Order Scleractinia 50 Order Tabulata 50 Phylum Bryozoa 50 Phylum Brachiopoda 54 Class Inarticulata 54 Class Articulata 56 Phylum Mollusca 56 Class Gastropoda 59 Class Pelecypoda 59 Class Cephalopoda 66 Subclass Nautiloidea 66 Subclass Ammonoidea 75 Subclass Coleoidea 78 Order Belemnoidea 78 Phylum Annelida 78 Phylum Arthropoda 78 Subphylum Trilobitomorpha 78 Class Trilobita 78 Subphylum Crustacea 80 Class Ostracoda 80 Phylum Echinodermata 80 Subphylum Pelmatozoa 81 Class Cystoidea 81 Class Blastoidea 81 Class Crinoidea 81 Subphylum Eleutherozoa 82 Class Asterozoa 82 Subclass Asteroidea 82 Subclass Ophiuroidea 82 Class Echinozoa 82 Subclass Echinoidea 82 Subclass Holothuroidea 85 Phylum Chordata 85 Subphylum Hemichordata 85 Class Graptolithina 85 Subphylum Vertebrata 86 Superclass Pisces 87 Class Agnatha 87 Class Placodermi 87 Class Chondrichthyes 87 Class Osteichthyes 87 Superclass Tetrapoda 89 Class Amphibia 89 Class Reptilia 89 Cotylosaurs 89 Turtles 89 Pelycosaurs 89 Therapsids 89 Ichthyosaurs 95 Mosasaurs 95 Plesiosaurs 95 Phytosaurs 95 Crocodiles and alligators 95 Pterosaurs 95 Dinosaurs 95 Order Saurischia 97 Suborder Theropoda 97 Suborder Sauropoda 97 Order Ornithischia 97 Suborder Ornithopoda 97 Suborder Stegosauria 97 Suborder Ankylosauria 97 Suborder Ceratopsia 100 Class Aves 100 Class Mammalia 100 Subclass Allotheria 100 Subclass Theria 100 Order Edentata 100 Order Carnivora 102 Order Pantodonta 102 Order Dinocerata 102 Order Proboscidea 102 Order Perissodactyla 104 Horses 104 Titanotheres 104 Chalicotheres 106 Rhinoceroses 106 Order Artiodactyla 106 Entelodonts 106 Camels 106 Books about fossils 108 General works 108 Nontechnical and juvenile 108 Collecting helps 108 Reference works 109 Selected references on Texas fossils 109 Glossary 111 Index 115

Illustrations

Figures— Page 1. Sketch of a coprolite—fossilized animal excrement 14 2. Sketch of a gastrolith—the gizzard stone of an ancient reptile 14 3. Dendrites—a typical pseudofossil 14 4. Types of symmetry in a fossil coral 24 5. Bilateral symmetry in fossil brachiopod 24 6. A brachiopod showing specimen number and accompanying label 31 7. Two types of micropaleontological slides 32 8. Typical Pennsylvanian crinoidal limestone 41 9. Typical Texas Foraminifera 49 10. Typical radiolarians 49 11. Morphology and principal parts of corals 50 12. Two types of bryozoans 50 13. Morphology and principal parts of articulate brachiopods 54 14. Lingula, a typical inarticulate brachiopod 56 15. Kingena wacoensis, a common Cretaceous brachiopod 56 16. Morphology and principal parts of gastropod shells 60 17. Morphology and principal parts of a typical pelecypod shell 65 18. Morphology and principal parts of the pearly nautilus 75 19. Characteristic features of the various types of cephalopod sutures 75 20. Types of typical fossil annelid worms 78 21. Morphology and principal parts of trilobites 80 22. Two extinct attached echinoderms, Pentremites and Caryocrinites 81 23. Typical modern crinoid, or “sea lily,” showing principal parts 81 24. Graptolites 86 25. Sketches of mastodon and mammoth teeth 104 26. Two views of a typical fossil horse tooth 104

Plates— Page 1. Geologic time scale Frontispiece 2. Types of fossil preservation 8 3. Silicified brachiopods dissolved from Permian limestones of the Glass Mountains, Brewster County, Texas 12 4. Dinosaur tracks in limestone in bed of Paluxy Creek near Glen Rose, Somervell County, Texas 15 5. Fossil collecting equipment 18 6-8. Fossil identification charts 28-30 9. Physiographic map of Texas 36 10. Geologic map of Texas 38-39 11. Geologic range of the major groups of plants and animals 45 12. Fossil plants—thallophytes and tracheophytes 46 13. Fossil plants—tracheophytes 47 14. Paleozoic sponges and sponge spicules 51 15. Pennsylvanian corals 52 16. Cretaceous and Tertiary corals 53 17. Pennsylvanian bryozoans and Cambrian and Mississippian brachiopods 55 18, 19. Pennsylvanian brachiopods 57, 58 20. Pennsylvanian gastropods 61 21. Pennsylvanian and Cretaceous gastropods 62 22, 23. Tertiary gastropods 63, 64 24. Pennsylvanian pelecypods 67 25-28. Cretaceous pelecypods 68-71 29-31. Tertiary pelecypods 72-74 32. Pennsylvanian and Cretaceous cephalopods 76 33. Cretaceous cephalopods 77 34. Fossil arthropods 79 35. Fossil starfishes, crinoids, and holothurian sclerites 83 36. Cretaceous echinoids 84 37. Primitive armored fish, shark teeth, and conodonts 88 38. Comparison of the dinosaurs 90 39. Comparison of Mesozoic flying and swimming reptiles 91 40. Pelycosaur, cotylosaur, and a primitive amphibian 92 41. Swimming reptiles 93 42. Phytosaur and flying dinosaurs 94 43. Skull of Phobosuchus, from Cretaceous of Trans-Pecos Texas 96 44. Saurischian dinosaurs 98 45. Ornithischian dinosaurs 99 46, 47. Cenozoic mammals 101, 103 48. Tertiary mammals 105 49. Cenozoic mammals 107

ERA PERIOD EPOCH CHARACTERISTIC LIFE CENOZOIC “Recent Life” QUATERNARY 1 MILLION YEARS Recent Pleistocene TERTIARY 64 MILLION YEARS Pliocene Miocene Oligocene Eocene Paleocene MESOZOIC “Middle Life” CRETACEOUS 70 MILLION YEARS JURASSIC 45 MILLION YEARS TRIASSIC 50 MILLION YEARS PALEOZOIC “Ancient Life” PERMIAN 55 MILLION YEARS CARBONIFEROUS PENNSYLVANIAN 30 MILLION YEARS MISSISSIPPIAN 35 MILLION YEARS DEVONIAN 55 MILLION YEARS SILURIAN 20 MILLION YEARS ORDOVICIAN 75 MILLION YEARS CAMBRIAN 100 MILLION YEARS PRECAMBRIAN ERAS PROTEROZOIC ERA ARCHEOZOIC ERA APPROXIMATE AGE OF THE EARTH MORE THAN 3 BILLION 300 MILLION YEARS

Texas Fossils An Amateur Collector’s Handbook

William H. Matthews III

INTRODUCTION

Almost everyone has seen the fossilized remains of prehistoric plants or animals. These might have been the skeleton of a gigantic dinosaur, the petrified trunk of an ancient tree, or the shells of snails or oysters that lived in the great seas that covered Texas millions of years ago.

Each year more and more people are learning that these fossils are more than mere curiosities. Instead, they are realizing that a good collection of fossils provides much information about the early history of our earth, and that fossil collecting can be a most enjoyable, fascinating, and rewarding hobby. It is for these people that Texas Fossils was written.

This publication is primarily an amateur collector’s handbook and as such offers many suggestions and aids to those who would pursue the hobby of fossil collecting. It tells, for example, what fossils are, where and how to collect them, and how they are used. Suggestions are made as to how the specimens may be identified and catalogued, and there are discussions and illustrations of the main types of plant and animal fossils. Included also is a simplified geologic map of Texas and a brief review of the geology of the State.

Texas Fossils is not a comprehensive study of the paleontology of Texas. Rather, it deals primarily with the more common species that the average collector is likely to find. These fossils are illustrated in the plates and figures, and these illustrations should be of some help in identifying the specimens in one’s collection. Included for completeness, however, are sketches and descriptions of some of the more rare and unusual fossils, and, for general interest, there are illustrations and descriptions of many of the extinct reptiles and mammals that once inhabited this State.

In addition, a group of selected references has been included for the reader who wishes to know more about earth history and paleontology. Many of these publications provide references of a more technical nature for the more advanced or serious collector, and some of them list excellent collecting localities.

A minimum of technical terminology has been used, but terms not commonly found in dictionaries, or which have not been explained in the text, are defined in the glossary (pp. 111-114).

Many people have helped in the planning, preparation, and completion of Texas Fossils, and their help is gratefully acknowledged: Dr. Keith Young, The University of Texas; Dr. Harold Beaver, Baylor University; and Professor Jack Boon, Arlington State College, offered helpful suggestions and information on Cretaceous fossils; Professors Richmond L. Bronaugh, Baylor University, and Jack T. Hughes, West Texas State College, provided information on vertebrate collecting localities; Professor Fred Smith, Texas A&M College, supplied data on Tertiary collecting localities and fossils which were used in illustrations; Dr. Saul Aronow and Professor Darrell Davis, Lamar State College of Technology; Dr. Jules DuBar, University of Houston; and Dr. Samuel P. Ellison, The University of Texas, made valuable suggestions which have been incorporated into the manuscript.

Special thanks are due Drs. John T. Lonsdale, L. F. Brown, Jr., and Peter U. Rodda, Bureau of Economic Geology, who critically read the manuscript and contributed greatly to the presentation of the material; Dr. John A. Wilson, The University of Texas, who read the section on vertebrate fossils and made invaluable suggestions and criticisms; Miss Josephine Casey, who edited the manuscript; and Mr. J. W. Macon, who prepared the maps and charts.

Thanks are due also to Dr. G. A. Cooper, United States National Museum, who prepared Plate 3 especially for this publication, and to R. T. Bird and the American Museum of Natural History for photographs used in Plates 4 and 43. Plates 38 and 39 were provided through the courtesy of Dr. J. W. Dixon, Jr., and the Geology Department of Baylor University. The other photographs were prepared by the writer. To Sarah Louise Wilson, Lamar State College of Technology, the writer gratefully acknowledges her tireless and painstaking efforts in preparing the many fine drawings which make up the balance of the illustrations.

WHAT ARE FOSSILS?

Fossils are the remains or evidence of ancient plants or animals that have been preserved in the rocks of the earth’s crust. Most fossils represent the preservable hard parts of some prehistoric organism that once lived in the area in which the remains were collected.

The word fossil is derived from the Latin word fossilis, meaning “dug up,” and for many years any unusual object dug out of the ground was considered to be a “fossil.” For this reason some of the earlier books dealing with fossils include discussions of rocks, minerals, and other inorganic objects.

There is much evidence to indicate that man has been interested in fossils since the very earliest times, and fossil shells, bones, and teeth have been found associated with the remains of primitive and prehistoric men. It is quite possible that the owners of these objects believed that they possessed supernatural powers, such as healing properties or the ability to remove curses.

During the earliest periods of recorded history, certain Greek scholars found the remains of fish and sea shells in desert and mountainous regions. These men were greatly puzzled by the occurrence of these objects at such great distances from the sea, and some of them devoted considerable time to an explanation of their presence.