BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 25, pp. 179-204, PLS. 4-8 MARCH 30, 1913 



GEOLOGICAL SECTION ALONG THE YUKON-ALASKA 



BOUNDAEY LINE BETWEEN YUKON AND 



PORCUPINE RIVERS ^ 



BY D. D. CAIRNES 



(Presented before the Society December 28, 1912) 



CONTENTS 



Page 



Introduction 179 



Previous work 180 



Topography 180 



General geology 182 



General statement * 182 



Table of formations IS! 



Metamorphic rocks 184 



Pre-Cambrian ( ?) — Yukon group 184 



Dominantly sedimentary rocks 187 



Lower Cambrian or pre-Cambrian — Tindir group. . , 187 



Devono-Cambrian limestones and dolomites 190 



Devono-Ordovlcian shale — chert series 195 



Carboniferous 19v^ 



General 19^ 



Shale series , X9t) 



Racquet group 197 



Nation River formation I99 



Permo-Carboniferous ( ?) conglomerate 199 



Mesozoic-Pennsylvanian— Orange group 201 



Quaternary — superficial deposits 202 



Igneous rocks 203 



Summary and conclusions 203 



In"troduction 



During the field seasons of 1911 and 1912, the writer was employed 

 mapping and studying the geology along the 141st meridian (the Yukon- 

 Alaska International Boundary) between Porcupine and Yukon rivers, or 

 between latitudes 67° 25' and 64° 40', a distance of 191 miles. This work 



1 Manuscript received by the Secretary of the Geological Society of America November 

 18, 1913. 



Published with the permission of the Director of the Geological Survey, Canada. 



(179) 



