CONTENTS 



CHAPTER PAGE 



I. General Principles 1 



II. General Principles — Concluded 23 



III. Origin and pre-Geologic History of the Earth .... 35 



IV. The Archeozoic Era 40 



V. The Proterozoic Era 47 



VI. The Cambrian Period 56 



VII. The Ordovician (Lower Silurian) Period 77 



VIII. The Silurian (Upper Silurian) Period 103 



IX. The Devonian Period 120 



X. The Mississippian (Lower Carboniferous) Period . . . 143 



XI. The Pennsylvanian (Upper Carboniferous) Period . . . 158 



XII. The Permian Period 180 



XIII. Summary of Paleozoic History 194 



XIV. The Triassic Period 201 



XV. The Jurassic Period 219 



XVI. The Cretaceous Period 236 



XVII. Summary of Mesozoic History 274 



XVIII. The Tertiary Period 281 



XIX. The Quaternary Period 328 



