RESUME OE LITERATURE. 83 



Keewatin by Lawson. It embraces the mica-schists and hornblende- schists 

 of Vermilion Lake and their equivalents, and lies between the graywackes 

 on the one side and the basal syenites and granites on the other. 



Adjacent to Vermilion Lake are hematite ores associated with jasper, 

 which are inclosed in a greenish magnesian schist, the bedding of Avhich 

 stands vertical. This schistose rock is probably of igneous origin, and in 

 its relations to the jasperoid rocks it fills all their cavities, overlying thein 

 unconformably, and holding fragments of the jasper, all indicating its later 

 origin. This igneous rock passes into a chlorite- schist, and this into the 

 sericite-schists and graywackes, which show unmistakable evidence of an 

 aqueous arrangement (pp. 219-221). The jasperoid is a sedimentary rock 

 (p. 245 et seq.) and not an eruptive, as has been supposed by Wadsworth 

 The rock was not, however, deposited in its present coiidition. The beds 

 have been upturned, folded, crushed, and affected by intense chemical 

 action. The ore is regarded as a result of chemical or metasomatic change. 

 The ore is a hard hematite and of such good quality as to warrant a guar- 

 ■\ntee of 67 per cent or more of iron, and 0.06 per cent or less of phosphorus. 



i'he general succession from above downward is as follows: (1) Grabbro. 



"_') Diabasic dolerite. These rest unconformably upon the lower members. 



(3) Reddish gneiss and syenite, which includes the Misquah Hills, White 

 Iron Lake and the Giants range (Mesabi heights). This is a case of a 

 fusion of sedimentary beds in situ, although it is not generally complete. 



(4) Graywacke, sericite-schist, argillite, quartzite, and jaspilite, which occur 

 about Vermilion Lake. (5) Mica-schist, hornblende -schist, and diorite — the 

 Vermilion group. (6) Mica-schist and granite, veined with syenite and 

 granulite. (7) Lower syenites and gneisses, generally regarded as Lauren- 

 tian. Nos. 3 to 7 are conformable, and Nos. 4 to 7 graduate into each other 

 (p. 355). 



The author states it as his opinion (p. 356) that there is reason for 

 believing that the Animikie rocks overlie the greenstone (No. 2) and 

 underlie the gabbro (No. 1) of the above succession. 



isss. 



WiNCHELL, N. H. Sixteenth Ann. Rept. Geol. and Nat. Hist. Survej!- Minn., 

 for 1887, 1888, pp. 13-129. 



Winchell, as customary, publishes in the annual report his field notes 

 for the preceding year, giving an abundance of details about the rocks of 



