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addition the rocks have been compressed more or less closely by a 

 force acting in an east-west direction. 



This report represents a vast mass of most detailed examination in 

 the field and in the laboratory, the completed form of which is to be 

 expected as a monograph of the U. S. Geological Survey. With this 

 will be issued maps, on the scale of four inches to the mile, showing 

 all outcrops and other details of structure and of topography. As 

 already stated, this report is the first successful attempt to present the 

 structure of the Marquette iron-bearing district, an area which has been 

 much studied before, but most of whose problems have remained 

 unsolved. While there are a few minor points yet unsettled, the major 

 questions have been answered. ^\vt. whole is a practical and success- 

 ful application of the advanced methods and principles of structural 

 geology applied to nonfossiliferous rocks, which methods and principles 

 have been so masterfully presented by the senior author. 



U. S. Grant. 



