TABLE OF CONTENTS 



INTRODUCTORY AND EXPLANATORY 



Use of scientific names, ix; estimates of age of earth, x; restora- 

 tions by Mr. Knight, x; Works of Reference, xi. 



I. FOSSILS, AND HOW THEY ARE FORMED 



Definition of fossils, 1; fossils may be indications of animals or 

 plants, 1; casts and impressions, 2; why fossils are not more 

 abundant, 3; conditions under which fossils are formed, 4; enemies 

 of bones, 4; Dinosaurs engulfed in quicksand, 5; formation of 

 fossils, 6; petrified bodies frauds, 6; natural casts, 7; leaves, 8; 

 incrustations, 9; destruction of fossils, 9; references, 10. 



11. THE EARLIEST KNOWN VERTEBRATES 



Methods of interrogating Nature, 11; thickness of sedimentary 

 rocks, 12; earliest traces of life, 13; early vertebrates diflncult of 

 preservation, 13; armored fishes, 14; abundance of early fishes, 

 15; destruction of fish, 16; carboniferous sharks, 19; known 

 mostly from teeth and spines, 19; references, 21. 



III. IMPRESSIONS OF THE PAST 



Records of extinct animals, 23; earliest traces of animal life, 23; 

 formation of tracks, 24; tracks in all strata, 24; discovery of 

 tracks, 25; tracks of Dinosaurs, 26; species named from tracks, 27; 

 footprints aid in determining attitude of animals, 29; tracks at 

 Carson City, 30; references, 31. 



IV. RULERS OF THE ANCIENT SEAS 



Ichthyosaurs and Plesiosaurs, 33; The Mosasaurs, 35; history of 

 the first known Mosasaur, 36; jaws of reptiles, 37; extinction of 

 Mosasaurs, 41 ; the sea-serpent, 41 ; Zeuglodon, 42; its habits, 43; 

 Koch's Hydrarchus, 44; bones collected by Mr. Schuchert, 45; 

 abundance of sharks, 47; the great Carcharodon, 47; arrange- 

 ment of sharks' teeth, 48; references, 49. 



