CHAPTER XII 



ENVIRONMENT OF THE TERTIARY FAUNAS OF THE PACIFIC 

 COAST OF THE UNITED STATES' 



RALPH ARNOLD 



CONTENTS 

 Introduction 

 Correlation Table 

 Acknowledgments 



The Eocene Period 



Relation of the Eocene to the Cretaceous 



Conditions immediately preceding and inaugurating the Eocene 



Distribution and character of sediments 



Conditions prevailing during the Eocene 



Orogenic movements and volcanic activity in the Eocene 



Climate during the Eocene 



The Oligocene Period 



The Oligocene a period of elevation 



Conditions of erosion and deposition 



Fauna and climate of the Oligocene 

 The Lower Miocene Period 



Conditions inaugurating the lower Miocene 



Distribution and character of sediments 



Conditions of deposition 



Volcanic activity in the lower Miocene 



Faunas and climate of the lower Miocene 



Period of diastrophism in the middle Miocene 



The Upper Miocene Period 



Distribution and conditions of deposition 



Erosion and volcanic activity 



Faunas and climate of the upper Miocene 



The Pliocene and Quaternary Periods 



Conditions of deposition and character of sediments 

 Diastrophism and volcanism in the Pliocene 

 Diastrophism in the Quaternary 

 Faunas and climate of the Pliocene and Pleistocene 



J Published by permission of the Director of the U. S. Geological Survey. 



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