CHAPTER I. 



By W. S. Bayley. 



GEOLOGICAL EXPLORATIONS AND LITEPtATURE. 



l^hat portion of the Lake Superior region knoNvn as the JIarquette iron 

 range was bronght to the notice of geologists Ijy the early navigatoi-s of 

 the lakes during the first quarter of the present century, and to the indus- 

 trial connnunity in the year 1850, when the surveyors of the Chip])ewa 

 land district announced the discovery of great masses of iron ore in the 

 valley of the Carj) River. The literature which deals with the geologv of 

 the district far exceeds in volume that devoted to all the other iron-ore- 

 producing areas in Michigan, Minnesota, and Wisconsin taken together. 

 This is due to the early discovery of the district, to its importance as an 

 ore producer, to its comparatively easy accessibility, and to the fact that its 

 geology is so complicated as to have afforded data for manv different theories 

 concerning it. These theories have given rise to frequent and sometimes 

 violent discussions, and though many have been proved untenable, they 

 have done mneli toward the development of correct notions of the origin 

 and the geological relationships of the various rocks occurring in the district. 



The history of the literature on the Marquette district may be divided 

 into four jjeriods, as follows: The first extending from the year 1820 to 1850, 

 the date of the appearance of Foster and Whitney's joint report; the second 

 beginning in 1850 and ending with the establishment of the Michigan survey 

 in 1870; the third beginning in 1870 and ending with the publication of 

 Rominger's report in 1881; and the fourth embracing the time that has 

 elapsed since 1881. 



