426 THE VERMILION IRON-BEARING DISTRICT. 



height of land may be subdivided into several minor ridges following the 

 general trend indicated. During its greatest advance the Lake Superior 

 lobe and the ice lobe to the north, called by Elftman" the Eainy lobe, were 

 confluent. As the ice receded these lobes became separated, their separa- 

 tion being determined by the high land just mentioned as lying north of 

 Lake Superior. For a time they were close together, forming an inter- 

 lobular moraine. As they receded and became more widely separated, each 

 formed independent moraines.'' Between these moraines there occurred 

 V-shaped areas, with the apex of the V pointing to the northeast, the arms 

 becoming more widely separated as they are followed to the west. 



No deposits of the Lake Superior lobe are known in the Vermilion 

 district. There has been recognized, however, and described by Upham," 

 a great moraine deposited by the Rainy lobe, which has been named by 

 him the Vermilion moraine. Moreover, the records of strise collected by 

 Upham ^ and inserted on his map in the same article show the direction of 

 the ice flow to have been in the main to the south-southwest, varying from 

 S. 10° to S. 50° W., and seem to corroborate Todd's division of the ice sheet 

 in this region into the two lobes as mentioned above. Since Upham's work 

 this Vermilion moraine has been further described and more accurately 

 delimited by Elftman."" No special study of the glacial deposits of the 

 Vermilion district has been made by the United States geologists, as the 

 work in this district was primarily undertaken with the object of deter- 

 mining the pre-Glacial geology. Nevertheless, observations made in the 

 course of the survey enable us to add a little to the knowledge of the course 

 in d'etail of this moraine. These observations have been made use of, and 

 accordingly the moraine has been traced as is shown on the accompanying 

 map (fig. 23. At the time of the formation of the moraine the ice in the 

 northeastern portion of the district passed over this east end of the Giants 

 range, and the moraine was deposited to the south of it. As we follow 



" The geology of the Keweenawan area in northeastern Minnesota, by A. H. Elftman; Am. GeoL, 

 Vol. XJ^I, Feb., 1898, p. 108. 



"Todd, op. cit, Am. Jour. Sci., 4th ser., Vol. VI, 1898, p. 473; Elftman, op. cit., pp 90-108. 



c Preliminary report of field work during 1893 in northeastern Minnesota, chiefly relating to the 

 glacial drift, by Warren Upham; Geol. Nat. Hist. Survey of Minnesota, Twenty-second Ann. Kept., 

 1893, pp. 18-66. 



f* Upham, op. cit., pp. 38-40. 



« Elftman, op. cit., p. 94. 



