470 J. E. Todd — Revision of the Moraines of Minnesota. 



7. Dover Moraine, extending into southern Kandiyohi 

 County. 



8. Bergus Falls Moraine, which passes Fergus Falls and 

 extends into Morrison County. 



9. Leaf Hills Moraine, forming with the preceding the main 

 portion of the Leaf Hills and extending into northern Todd 

 and Morrison Counties, thence east-northeast nearly to Grand 

 Marais on the north shore of Lake Superior. 



10. The Itasca Moraine which surrounds Lake Itasca, runs 

 south of Leach and Pokegoma Lakes nearly to Grand Portage 

 on Lake Superior. 



11. Mesabi Moraine, which separates the two portions of 

 Red Lake, lies along the divides of Cass and Winnibigoshish 

 Lakes, thence forms the so-called Mesabi range and strikes 

 Lake Superior at Pigeon Point. 



12. Vermillion Moraine, which lies south of Net, Pelican 

 and Vermillion Lakes. 



The following objections present themselves to this inter- 

 pretation : 



First, it assumes that latitude had more to do with the move- 

 ment of the ice sheet than altitude. This is contrary to what 

 we learn either from the movements of existing ice sheets in 

 Greenland and Alaska, or in the case of the Dakota and 

 Michigan lobes of the Pleistocene ice. It is true almost with- 

 out exception that in the zone of ablation the ice seeks the 

 lowest levels with a persistence nearly equal to that of water. 

 There can be no question that the ice, at least in its later 

 stages, lay in the zone of ablation rather than in the zone of 

 accumulation. The scheme presented above shows little or 

 none of this rule. The ice is represented as vacating the Lake 

 Superior basin and the Red River valley much sooner than it 

 did the elevated region around Itasca. The abrupt rise along 

 the northwest shore of Lake Superior of more than a thousand 

 feet seems not to have exerted any perceptible influence on the 

 direction of the Leaf Hills and Itasca Moraines. In the Mesabi 

 Moraine southeast of Red Lake we lind it rising from about 

 1200 feet at Red Lake to more than 1400 feet on a divide 

 without apparently responding to the influence of the surface 

 at all. In fact, instead of running westward down the slope, as 

 would be analogous to known cases, Mr. Upham represents it 

 as turning eastward so as to form a reentrant angle. 



Second, it does not represent the ice as retiring in the 

 proper direction to explain the formation of the early stages of 

 Lake Superior, when it formed beaches 500 feet above the 

 present lake around its western end and discharged through 

 the St. Croix River. Nor is it in harmony with the subse- 

 quent or contemporaneous retreat of the edge of the ice dur- 



