KESUME OF LITERATURE. 93 



WiNCHELL, H. V. Report of field observations made during the season of 1888 

 in the iron regions of Minnesota: Seventeenth Ann. Rept. Geol. and Nat. Hist. 

 Survey of Minn., for 1888, 1889, Tpp. 77-1-15; see also The diabasic schists containing 

 the jaspilite beds of northeastern Minnesota: Am. Geologist, Vol. Ill, 1889, pp. 18-22. 



In the above H. V. Wincliell gives further observations on the iron 

 regions of Minnesota. On the Griants range the Animikie is found to rest 

 upon the syenite. There is a semicrystaUine rock between the two, which 

 grades into the syenite. The character of the transition is not metamorphic, 

 but rather fragmental, there appearing to be a certain amount of loose 

 crystalhne material which has resulted from the decay and erosion of the 

 syenite lying on top of this rock in the bed of the sea, upon and around 

 which the Animikie sediments were deposited. The coarse detritus grades 

 up into the fine detritus of the Animikie (p. 86). The Animikie beds are 

 found also to rest unconformably upon the upturned edges of the Keewatin 

 schists (p. 87). The same relations are found to prevail in the Birch Lake 

 region (p. 91). The gabbro containing ores in the vicinity of Kawishiwi 

 River are found to contain fragments of the Animikie slates and quartzites, 

 and is therefore of later origin (pp. 96-97). At Gunflint Lake the Animikie 

 rests unconformably upon the Keewatin (p. 104). The Keewatin schists 

 are largely of eruptive origin (p. 132). The contacts of the jaspilite with 

 the basic schists are abrupt and angular, and numerous fragments are found 

 contained in the schists. The jaspilite is regarded as a sedimentary forma- 

 tion, which was broken up and involved in the eruptions of Keewatin 

 time. The Huronian quartzite, associated with the magnetite, lying 

 unconformably upon the syenite, is believed to lie conformably upon the 

 Animikie slates (p. 133). 



Grant, Ulysses S. Report of geological observations made in northeastern 

 Minnesota during the summer of 1888: Seventeenth Ann. Rept. Geol. and Nat. Hist. 

 Survey Minn., for 1888, 1889, pp. 117-215. 



Li this report Grant gives an account of tlie geologic observations 

 made by him in northeastern Minnesota. 



North of Gunflint Lake the vertical Keewatin slates and Vermilion 

 crystalline schists, with an east and west strike, strike directly across a 

 range of immediately adjacent gneisses, the schists showing no evidence of 

 being twisted or bent within 200 feet of the gneiss. In the syenites of 

 Gunflint Lake are found fragments of schist, which indicate that the syenite 

 is eruptive later than the schists (p. 159). 



