VOLUME XXVII NUMBER 3 



THE 



JOURNAL OF GEOLOGY 



APRIL-MAY igiQ 



THE BUILDING OF THE COLORADO ROCKIES 



ROLLIN T. CHAMBERLIN 



The University of Chicago 



CONTENTS 



Introduction 



The Colorado Rockies 



History of the Main Range 



Laramide Diastrophism 



Early Tertiary Folding 



Peneplanation 



Upbowing 



Erosion and Glaciation 

 The Lyons-Grand River Section 

 The Shortening of the Crust 

 The Elevation of the Folded Tract 

 The Thickness of Folded Shell 

 General Discussion and Conclusions 



PART I 



INTRODUCTION 



Many phases of geology involve little more than an under- 

 standing of vi^hat has taken place at or near the surface of the 

 earth. They can thus be studied more or less directly. A study 

 of diastrophism, however, involves in addition a consideration of 

 what has taken place at greater depths. The visible mountain 

 range is but the outward expression of more deeply operating forces. 



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