BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 VOL. 13, PP. 253-266 AUGUST 6, 1902 



GEOLOGICAL RECONNAISSANCES IN SOUTHEASTERN 



ALASKA * 



BY ALFRED HULSE BROOKS 



{Presented before the Society January 2, 1902) 



CONTENTS 



Page 



Introduction 253 



Geography 254 



Geology 256 



Stratigraphy , ■ 256 



Summary 261 



Correlation 264 



Introduction 



During the summer of 1901 the writer, assisted by Mr Corey C. Bray- 

 ton, spent about two months in making a preliminary reconnaissance of 

 the Ketchikan mining district, and later about one month in a more 

 general reconnaissance of other parts of southeastern Alaska. The re- 

 sults of this work are to be published by the U. S. Geological Survey in 

 a report entitled " Preliminary Report on the Ketchikan Mining District 

 of Southeastern Alaska.' 1 In view of the little that is known of this 

 region, it has seemed worth while to abstract the more important con- 

 clusions bearing on the general geology of the region. 



A few small areas in this region have been studied in some detail and 

 many facts have been gathered, but almost no attempt has been made 

 to correlate them. The work of the Canadian geologists, however, near 

 the boundary and in British Columbia has added to the knowledge of 

 the stratigraphic succession and of some of the larger structural fea- 

 tures. Every worker in the field must acknowledge his indebtedness to 

 Dr George M. Dawson, f who has contributed so much to our knowledge 

 of the geology and resources of the northwestern part of v our continent. 



* Published by permission of the Director of the United States Geological Survey, 

 f Geo. M. Dawson : Report on an exploration in the Yukon district, N. W. T., and adjacent por- 

 tions of British Columbia. Ann. Rept. Geol.'and Nat. Hist. Survey, Canada, 1887, part B. 



XXXVIII— Buli,. Geol. Soc. Am., Vol. 13, 1901 (253) 



