418 



W. UPHAM ESKER NEAR WINNIPEG, MANITOBA 



flowing from the melting ice-sheet, mostly in its waning stages at the end 

 of the Glacial period, was thought out and published by D. Hummel and 

 N. 0. Hoist in Sweden and Prof. N. H. Winchell and the present writer 

 in the United States.'* 



Along the course of this gravel and sand ridge of Birds Hill a stream 

 poured from the glacial melting and attendant rains, walled on each side 

 by yet remaining tracts of the retreating continental ice-sheet, which 

 gradually rose to greater heights westward and northward. The very 

 plentiful limestone pebbles and the slight easterly dips of many portions 

 oi the esker beds demonstrate that this small river flowed southeast and 

 east. 



Wherever belts of marginal moraine hills or low hillocks and ridges are 

 typically developed, as they have been traced and mapped continuously 

 across more than half of our continent, from Cape Cod and Long Island 

 to the northwestern plains of Alberta, with much interlocking and wide 

 diversity of topographic expression and drift material, these moraines 

 always include, within any district of much extent, considerable accumu- 

 lations of stratified gravel and sand, frequently amassed separately from 

 the marginal till and boulders, so that they form kames, that is, low 

 mounds and knolls or sometimes prominent hills, and occasionally eskers, 

 which are prolonged kames, associated with the other and more strictly 

 moraine hills of till. 



Birds Hill and the contiguous kames. Moose Nose and Oak Hummock, 

 may be referred in general to glacial streams temporarily existing at 

 rome time during the stage of the receding ice-sheet when the Itasca 

 moraine in Minnesota was heaped along its boundary ; but on the area of 

 Lake Agassiz all the moraine belts that cross it are indistinctly or quite 

 interruptedly recognizable. These fluvial hills of gravel, with overlying 

 and underlying till, are the most noteworthy drift accumulations that are 

 found in the probable course of the Itasca moraine on this lacustrine area. 



* The early studies of Hummel and Hoist, in 1874-1876, on the eskers of Sweden, 

 where this class of drift formations has more extensive development than anywhere else 

 in the World, are cited by Prof. James Geikie in "The Great Ice Age," second edition, 

 3877. pp. 414, 415. 



N. H. Winchell : Geological and Natural History Survey of Minnesota, Second Annual 

 Report, for 1873, p. 194. 



Warren Upham : On the origin of kames or eskers in New Hampshire. Proceedings 

 of the American Association for the Advancement of Science, vol. xxv, for 1876, pp. 216- 

 225 ; Geology of New Hampshire, vol. iii. 1878, pp. 12-14. 



Consult also the IT. S. Geological Siirvey Monograph xxxiv. 1899, The glacial gravels 

 of Maine and their associated deposits, by Prof. George H. Stone, treating of the region 

 having the longest and most abundant eskers in North America. 



