CHAPTER VII. 



THE DRIFT. 



The Vermilion district, like all the rest of the Lake Superior region, was 

 overridden by the great ice sheets of Glacial time. The tendency of the 

 glacial action during the advance of the ice sheet was, of course, to reduce 

 this district to a general level, to round the hills, and produce striae upon 

 the rock surfaces, thus marking the direction of its movement. In its retreat 

 this process of leveling was continued by the filling in of the pre-Glacial 

 valleys with morainal deposits. While it is known from the researches of 

 the glacialists that the Lake Superior region, and of course that part of it 

 here discussed, was covered several times by ice sheets, we can recognize 

 in the Vermilion district the effects of the ice only during the last or Wis- 

 consin stage of the Glacial epoch, to which consequently belong all of the 

 deposits which will be briefly described. 



According to Prof J. E. Todd, the glacial deposits of northeastern 

 Minnesota can be referred "to two great lobes of the ancient ice sheet, a 

 shorter one moving southwest through the Lake Superior Basin, and a longer 

 one moving around this from the noi'theast to the west and southwest."" 



In oi'der that the reader may get a clear idea of the glacial history of 

 the Vermilion district, it may be well to make some general statements 

 concerning the glacial history of that portion of Minnesota which is adjacent 

 to but outside of the district considered in this paper. Extending in an 

 approximately northeasterly direction through northeastern Minnesota there 

 is a height of land which forms the watershed between the hydrographic 

 basins of Lake Superior on the south, belonging to the continental St. 

 Lawrence basin, and between the basin of the Rainy River and Lake of the 

 Woods, which belongs to the great Hudson Bay basin on the north. This 



a A revision of the moraines of Minnesota, by J. E. Todd: Am. Geol., Vol. XVIII, 1896, pp. 

 225-226, a paper read at the August meeting of the American Association for the Advancement of 

 Science, before Section E, Geology and Geography. Also, Am. Jour. Sci., 4th ser., Vol. VI, 1898, 

 p. 473. 



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