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[1]

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.