502 W. UPHAM STAGES OF THE ICE AGE 



west coast of James Bay and along the Attawapishkat, Albany, and 

 Kenogami rivers, and that its fragments were found by him as far west 

 as to Lonely Lake and south to Lake Superior, 8 Farther to the southwest 

 and south I have observed fragments of it, usually measuring only a few 

 inches, but in some instances a foot or more in diameter, occurring very 

 rarely in the drift in the northeastern part of North Dakota, where the 

 largest piece ever found by me was about 30 miles south of the interna- 

 tional boundary and 50 miles west of the Eed River, and at numerous 

 localities in Minnesota, where it extends at least as far south as Steele 

 County, 75 miles south of Saint Paul and 1,000 miles southwest of its 

 outcrop north of James Bay. 



The drift travel so known, like the instances before cited, is referable 

 mainly to the Nebraskan glaciation and to a great Labradorian ice* cur- 

 rent, for the later Keewatin currents, during the Kansan and ensuing 

 glacial stages, could not permit drift derived from Hudson and James 

 bays to be borne so far to the west. Moreover, the far southward trans- 

 portation into southeastern Minnesota covered too great a distance to be 

 due to the Kansan and later glaciation, although it may partly be so 

 explained. After Nebraskan travel to northwestern Minnesota, the Steele 

 County boulder may have been carried southeast during Kansan time, 

 taking then a course nearly at right angles with its earlier journey. 



From a review of these notes of boulders carried far by glacial currents, 

 it appears that during an early part of Nebraskan time the Patrician 

 radial outflow reached west across northern Minnesota as well as south 

 across Michigan and Ohio. Afterward, probably during the greater part 

 of that very long stage, its directions of glacial flow respectively upon the 

 Keewatin and Labradorian areas in these States were nearly like the 

 currents of the later Kansan and Illinoian icefields. 



Chains of lakes in southern Minnesota, described in preceding pages, 

 show that the drift there was mostly deposited before a great recession of 

 the ice-sheet which is referred to the Aftonian stage. Three localities 

 .farther north in this State supply definite measures of the moderate thick- 

 ness of the drift referable in these places to the Kansan and later stages, 

 agreeing with the evidence of these lakes. 



At New Ulm, about 30 miles distant northward, the later drift sheet, 

 overlying a sand and gravel deposit- that is probably Aftonian, has a thick- 

 ness of 16 to 18 feet. Eushseba township, in Chisago County, about 50 

 miles north of Saint Paul and Minneapolis, has a surface sheet of till 10 



8 Geol. and Nat. Hist. Survey of Canada, Annual Report, new series, vol. ii. for 1886, 

 p. 36G ; compare Report of Progress for 1878-79, pp. 22, 23C. 



