. RESUME OF LITERATURE. 125 



and if the similarity were complete, the correlation would involve laying 

 too much stress on lithologic similarity of widely separated formations. 

 Professor Winchell's latest conclusion, that the Mesabi greensand is 

 volcanic and not organic, while entirely dissented from by others who have 

 studied this rock, in itself spoils his argument based on similarity. The 

 third argument in favor of the Cambrian age of the Animikie, based on the 

 extent of the ixnconformity beneath the Animikie, has little value when 

 unsupported by the other lines of evidence. Professor Winchell's conclusion 

 as to the Cambrian age of the Animikie strata is thus not adequately 

 sustained by the reasons given. The view that the Animikie is Upper 

 Huronian (pre-Cambrian) is the commonly accepted one. The evidence 

 favoring this view is summarized by Van Hise." 



Further comment on the above work would require reference to the 

 detailed observations made in northeastern Minnesota during four 3-ears by 

 the Lake Superior Division of the United States Geological Survej'. The 

 results of this work are published in this monograph. In g-eneral it may 

 be stated that now, as in the past, there is a divergence in the conclusions 

 reached by the Minnesota survey and by the United States Geological 

 Survey concerning the position and importance of the unconformities, the 

 correlation of series, and the nomenclature. 



1900. 



Coleman, A. P. Copper and iron regions of Ontario; with Report of the Ontario 

 Bureau of Mines, 1900, pp. 143-191. 



This paper deals incidentally with the Vermilion district (pp. 150-154). 

 Before the regular field work was begun in Ontario the author, accom- 

 panied by Prof Arthur B. Willmott, visited the Lake Superior iron ranges 

 of the United States. The Vermilion range was visited, among others, and 

 a few desultory observations concerning the mines and rocks in the vicinity 

 of the mines are recorded. 



Grant, U. S. Contact metamorphism of a basic igneous rock: Bull. Geol. Soc. 

 Am., Vol. II, 1900, pp. 503-510. 



Along the northern edge of the Great gabbro mass of northeastern 

 Minnesota there occur certain peculiar crystalline rocks. These have been 

 jDroduced by the contact action of the gabbro on rocks of varied lithologic 



"Correlation Papers, Archean and Algonkian, Bull. U. S. Geol. Survey No. 86; Principles of pre- 

 Cambrian geology: Sixteenth Ann. Rept. U. S. Geol. Survey, Pt. I, 1896, pp. 571-874. 



