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
[Illustration: Plate 1
GEOLOGIC TIME SCALE]
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