174 REVIEWS 



Comment. — Conclusions 5 and 6 are essentially in accord with conclusions reached 

 by United States geologists who have worked in this area, although differing in nomen- 

 clature and minor points. The same may be said of Conclusion 7 in the matter of 

 a greenstone being the oldest rock in the state, although Professor Winchell is alone 

 in calling it the earliest crust of the globe. From Conclusions 8, 9, 10, and 11 the 

 United States geologists dissent in toto. Adequate discussion of these conclusions 

 would involve covering the entire range of Minnesota geology. The reader is referred 

 to Monographs XLIII,^ and XLV,^ and to pp. 305-4343 of Part III of the Twenty- 

 first Anmial Report of the U. S. Geological Survey for such a discussion. 



N, H. Winchell. "Sketch of the Iron Ores of Minnesota," American 



Geologist, Vol. XXIX, pp. 154-62. 



Winchell briefly describes the iron ores of Minnesota, and incidentally sketches 

 their geological relations. No new points are added to those previously presented. 



Robert Bell. "Report on the Geology of the Basin of Nottaway River." 

 Annual Report of the Geological Survey of Canada for igoo, Vol. XIII, 

 Part K, IQ02. 



Bell describes and maps the geology of the basin of the Nottaway River. 

 Granites and gneisses referred to the Laurentian occupy the larger portion of the area. 

 They are for the most part intrusive into the crystalline schists referred to the 

 Huronian. Huronian rocks occur principally in a large area that is near the center of 

 the region, and in small areas north of the center of the region and south of Lake 

 Mistassini in the eastern part. The large tract of Huronian rocks forms a part of 

 the great belt of Huronian rocks extending continuously from the eastern side of Lake 

 Superior to Lake Mistassini, a distance of seven hundred miles. The Huronian may 

 be grouped in three classes, namely: (i) crystalline schists, together with some other 

 rocks forming a comparatively small proportion of the same series ; (2) massive green- 

 stones; and (3) granites. The schists embrace a considerable variety, but the greater 

 part of them are dark green and hornblendic or dioritic, and they often pass into more 

 or less massive greenstones, so that it becomes difficult to map the two varieties sepa- 

 rately. Dolomite, quartzite, arkose, conglomerate, and agglomerate are exceptional 

 occurrences. 



J. Burr Tyrrell and D. B. Bowling. "Reports on the Northeastern 

 Portion of the District of Saskatchewan and Adjacent parts of the Dis- 

 tricts of Athabasca and Keewatin," Annual Report of the Geological 

 Survey of Catiada for igoo, Vol. XIII, Parts F and FF, 1902. With 

 map. 



Tyrrell and Dowling report on the northeastern portion of the district of Sas- 

 katchewan, and adjacent parts of the districts of Athabasca and Keewatin, comprising 

 an area adjacent to the north end of Lake Winnipeg. The east, northeast, and northern 



^ C. K. Leith, "The Mesabi Iron-Bearing District of Minnesota," Monograph 

 XL HI, U. S. Geological Survey, 1903. 



*J. Morgan Clements, "The Vermilion Iron-Bearing District of Minnesota," 

 Monograph XLV, U. S. Geological Survey, 1903. 



3C. R. Van Hise, The Iron Ore Deposits of the Lake Superior Region, Twenty- 

 first Amtual Report of the U. S. Geological Survey, Part III, pp. 305-434. 



