INTRAFORMATIONAL CORRUGATED ROCKS 



WILLIAM J. MILLER 



Smith College, Northampton, Massachusetts 



CONTENTS 



Introduction 



DiPPERENTlAL MOVEMENT ACCOMPANYING ThRUST FAULTING 



Differential Movement Accompanying Normal Faulting 



Differential Movement Accompanying Regional Folding 



Differential Squeezing Accompanying Regional Folding 



Differential Movement Under the Action of Gravity 



Subaqueous Gliding or Slumping 



Action of Ice 



Differential Weighting 



Crystallization and Hydration 



Pressure of Intruding Magmas 



Action of Magmatic Injection 



Magmatic Flowage 



INTRODUCTION 



It is the purpose of this paper to enter into a general discussion 

 of intraformational contorted rocks, with emphasis upon the modes 

 of origin of the different types. During the last eighty years various 

 examples have been described, but it is surprising how few are the 

 cases which have been discussed in sufl&cient detail to furnish the 

 data necessary for their classification on the basis of origin. Evi- 

 dently these interesting and often puzzling structures have not 

 received the attention which they deserve. In the present attempt 

 to make a tentative genetic classification of intraformational corru- 

 gations, examples, mainly from American localities, are given to 

 illustrate the various t3Apes. Because of the lack of certain critical 

 data, it is difficult or impossible to be very sure of the proper 

 classification of some of the cases. 



DIFFERENTIAL MOVEMENT ACCOMPANYING THRUST FAULTING 



Excellent examples of corrugated strata between practically 

 imdisturbed strata occur in the walls of the postglacial gorge at 



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