410 W. UPHAM ESKER NEAR WINNIPEG, MANITOBA 



the section on the southern side, near the axis of the esker, consists 

 mainly of sand, the depth of the pit there being 50 feet. 



The stratification here and throughout all the 4 miles of the esker is 

 approximately level, with occasional slight inclination eastward, but has 

 frequent disturbed or confused portions adjoining either side and wher- 

 ever very coarse gravel abounds. Torrential oblique bedding of the finer 

 layers is frequent, any nearly horizontal layer 1 to 2 feet or more in 

 thickness having often a secondary "flow and plunge structure,'^ or cross- 

 bedding, with dips from 10 to 30 degrees or rarely steeper, almost in- 

 variably inclining downward from west to east. 



Paleozoic limestones make up about 75 to 90 per cent of the gravel, 

 the remainder being Archean granites, gneiss, and schists ; and such pro- 

 portions are observed through the whole course of the esker. It is thus 

 known, by evidence of the cross-bedding and of the sources of the gravel 

 and sand, that this esker was deposited by a glacial river flowing east- 

 ward, deriving its drift from the part of the waning ice-sheet lying on 

 the west, where limestone formations cover large areas. 



Above the esker sand and gravel along this western mile a thin envelope 

 of true till, mostly continuous at the top of the sections both on the south 

 and north sides of the excavation, forms a most remarkable and in- 

 structive feature, which is presently to be fully described, with ensuing 

 discussions of its significance concerning the amount of the drift that 

 was englacial and finally superglacial, and in its bearing on the conditions 

 of deposition of eskers. 



Within the 22 years since my former observations here, this excava- 

 tion has been widened, and it has been continued about 300 feet south- 

 ward from its former eastern end. Then no considerable excavation had 

 been made along the farther course of this esker eastward; but at the 

 present time the aggregate removed from the eastern gravel and sand pits 

 probably exceeds the amount thus far taken from the excavation already 

 described, adjoining Birds Hill Station. About a quarter or a third part 

 of the whole esker has been removed. At the same rate, disregarding its 

 prospective increase on account of the present rapid increase of building 

 in Winnipeg, this esker will be almost completely removed during the 

 next 40 or 50 years. 



Plate 31, the frontispiece of this paper, comprises a map and sections 

 of this prolonged ridge, and of two noteworthy kames a few miles 

 east and southeast, called Moose Nose and Oak Hummock, which are 

 short and nearly round hills of similar material and origin as this esker. 

 The map also shows associated gravel plateaus, ridges, and hills on the 

 northeast. 



