Editorial. 



The recent publication by the United States Geological Sur- 

 vey of monographs on the Mesabi, Vermilion, and Menominee iron- 

 bearing districts marks the approximate completion of a prolonged 

 and systematic study of the great Lake Superior ore-bearing series 

 and of the associated pre-Cambrian formations. There is yet to 

 appear a supplementary and final volume on the geology of the Lake 

 Superior region as a whole, which will bring together and correlate 

 the general conclusions and maps of the district monographs. It is 

 understood that this will be submitted for publication in 1905. 



This notable series of reports was formally inaugurated in the 

 late eighties by Dr. R. D. Irving, but was prefaced by his work on 

 the Wisconsin survey in the seventies and early eighties. Dr. Irving's 

 death in 1888, however, permitted him to see only the beginning of 

 the monographic work in the Penokee- Gogebic district. The further 

 execution of the plan fell to his associate, Dr. C. R. Van Hise, who, 

 during the past sixteen years, has carried it forward to its present 

 advanced stage. The first of the monographs to appear was the 

 Penokee- Gogebic monograph. No. XIX, published in 1892. The 

 field work for this was done jointly by Irving and Van Hise, but the 

 writing of the monograph fell largely to the latter. In 1895 appeared 

 the Marquette monograph, No. XXVIII, by Van Hise in collabora- 

 tion with Professor W. S. Bayley. This was followed in 1899 by the 

 appearance of the Crystal Falls monograph, No. XXXVI, by Pro- 

 fessors J. Morgan Clements, H. L. Smyth, W. S. Bayley, and C. R. 

 Van Hise; in 1903, by the Mesabi monograph, No. XLIII, by Dr. 

 C. K. Leith; and finally, during the past winter, by the Vermilion mon- 

 ograph. No. XLV, by Clements and the Menominee monograph, 

 No. XLVI, by Bayley, the latter having just come from the press. 

 Monograph V, on the copper-bearing rocks of Lake Superior, by 

 Irving, should also be mentioned, although it was published before 

 (1883) the inauguration of the plan for the comprehensive investiga- 

 tion of the iron-bearing districts. 



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