EXISTING GLACIERS AND WISCONSIN GLACIATION 689 



Milk River Valley, where, however, they had but relatively small exten- 

 sion. The relations of these spillways show that the thickness of ice in 

 the North Fork Valley must have been about 1,000 feet just east of the 

 mountain front. 



Saint Mary River Valley and its tributaries were occupied with ice 

 which formed a glacier of large size, extending northward across the 

 49th parallel. The main stream heading, where now lie the Blackfeet 

 and Red Eagle glaciers, thus had a length of about 35 miles south of the 

 international boundary, and extended an undetermined distance north- 

 ward over the plain of southern Alberta. The main tributaries occu- 

 pied the valleys of Red Eagle, Boulder, Swiftcurrent, and Kennedy 

 creeks. Glacial drift was found on the slope of Singleshot Mountain up 

 to 1,275 feet above the foot of Upper Saint Mary Lake, and the position 

 of the lateral moraine just below the crest of Saint Mary Ridge on the 

 east shows that the surface of the glacier stood about 1,350 feet above 

 the level of Lower Saint Mary Lake. 



West of Chief Mountain is Belly River Valley. Heading at the Conti- 

 nental Divide, 10 to 12 miles south of the 49th parallel, where are now 

 Chaney and neighboring glaciers, a considerable stream of ice extended 

 northward onto the plain of southern Alberta. Still farther west a large 

 glacier issued from the valley west of the north end of the Lewis Range, 

 in which is now Waterton Lake. The extent of this stream of ice in 

 Alberta was not determined, but its depth is known to have been con- 

 siderable, for ledges smoothed and striated by this glacier were found 

 on the mountain slope about 1,700 feet above the head of Waterton Lake. 



The fresh and unmodified character of all the phenomena resulting 

 from this extensive mountain glaciation indicates that it is probably to 

 be correlated with the last of the great extensions of the Keewatin ice- 

 sheet, that of the Wisconsin stage of glaciation, and this correlation is 

 assumed in the present discussion. The purpose of this present paper 

 is not, however, the discussion of this later well known glaciation, but 

 the description of certain deposits which indicate that the Lewis and 

 Livingston ranges were subjected to glaciation at another and much 

 earlier stage. 



the north and south forks of Cut Bank Creek, and the name "Two Medicine Ridge" to 

 the ridge north of Lower Two Medicine Lake. The name "Toint Mt.," which is printed 

 on the map on the ridge hetween Swiftcurrent and Boulder creeks, is applied by the 

 people of the region to the mountain to the southwest for which the map shows the 

 name "Altj^n Mt." It is proposed to transfer the name "I*oint Mt." to this peak and to 

 designate the ridge between Swiftcurrent and Boulder creeks as "Boulder Ridge." The 

 ridge north of Swiftcurrent Creek will be referred to as "Swiftcurrent Ridge." The 

 name "Kennedy Ridge" will be ai)pli("d to the rid.uo willi two crests north of North Fork 

 of Kennedy Creek. 



