BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 34, pp. 679-702 , December 30. 1923 



PEE-CAMBRIAN FOLDING IN NORTH AMERICA ^ 



BY WILLIAM J. MILLER 



{Presented before the Society December 29, 1922) 



CONTENTS 



Page 

 Introduction 679 



General considerations 681 



Degree of folding of earlier pre-Cambrian rocks 681 



Post-Cambrian folding of pre-Cambrian rocks 683 



Lack of records for much of the continent 686 



Significance of the duration and subdivisions of the pre-Cambrian . . . 686 



Observed strikes of pre-Cambrian folding and foliation 688 



General statement 688 



Labrador, Nova Scotia, and New Brunswick 689 



Eastern Canada 689 



Quebec 689 



Ontario 689 



Manitoba 690 



Western Canada 690 



Eastern United States 691 



Northern New York 691 



New England 691 



Appalachian-Piedmont region 692 



Minnesota, Wisconsin, and Michigan 692 



Missouri and South Dakota 693 



Texas 693 



Arizona and New Mexico 694 



Nevada and Utah 694 



Colorado 695 



Wyoming 696 



Montana and Idaho 697 



Conclusions regarding the Cordilleran region 697 



General conclusions 698 



Discussion 699 



Introduction 



Any serious attempt to decipher the pre-Cambrian paleogeography of 

 the continents, even if only in broad outline, should be commended. Ai\ 



1 Manuscript received by the Secretary of the Society February 26, 1923. 



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