VOLUME XXIII NUMBER 8 



THE 



JOURNAL OF GEOLOGY 



NOVEMBER-DECEMBER 1915 



A REVISION OF THE SEQUENCE AND STRUCTURE OF 



THE PRE-KEWEENAWAN FORMATIONS OF THE 



EASTERN GOGEBIC IRON RANGE OF 



MICHIGAN 



R. C. ALLEN 

 State Geologist of Michigan 



AND 



L. P. BARRETT 



Assistant Geologist, Michigan Geological Survey 



INTRODUCTORY STATEMENT 



This paper is a brief presentation of the main results of recent 

 studies of the geology of the Gogebic iron range in Michigan from 

 T. 47 N., R. 45 W., east to Gogebic Lake, a distance of 16 miles. 



Former interpretations of the geology are based almost entirely 

 on early investigations of the United States Geological Survey^ 

 recently summarized in Monograph 52. Prior to this work four 

 years of study of the pre-Cambrian of the region south and east 

 of Gogebic Lake to the Iron River district, including 38 townships 

 adjacent in northern Wisconsin, by the senior writer and his 

 assistants had failed to estabhsh a satisfactory basis of correlation 

 with the rocks of the Gogebic Range. Inasmuch as recent drilling 

 for iron ore has supplied important information, unavailable to 



' C. R. Van Hise and R. D. Irving, Monograph ig, U.S. Geol. Survey. 

 Vol. XXIII, No. 8 689 



