CONTENTS 



CHAPTER PAGE 



Introduction 1 



i.— how the history of the past is read . 7 

 II.— Divisions of life and time . . . .28 



III.— The era of invertebrates .... 58 

 IV.— The coming of vertebrates and the rise 



OF fishes 85 



V. — Great salamanders and their associates 113 



VI. — The reign of reptiles 143 



VII.— Early birds and mammals .... 177 



VIII. — Dragons of sea and air .... 194 



IX.— The rise of the mammals .... 220 



X.— The life of yesterday .... 251 



XI.— Looking backward 274 



Index 287 



