158 C. IV. Hayes — Expedition through tli.e Yukon District. 



glaciated high up their sides, and it is probable that those de- 

 tached southern portions of the interior plateau already de- 

 scribed were not wholly covered by ice, even Avhen the Cordil- 

 leran glacier had its greatest extension. The absence of a 

 terminal moraine along the northern limit of the glaciated area 

 would indicate that the Kluantu valley was filled by ice from 

 comparatively small streams bearing little moraine material. 



Southward from the Kluantu valley, records of former ice 

 action continued to the coast, but the giaciation was by no means 

 so intense as one might be inclined to expect from the high 

 latitude of the region and the great altitude of the neighboring 

 mountains. The marks of this former general giaciation have 

 been removed from many of the river valleys, or at least greatly 

 obscured by more recent glaciers which have but lately with- 

 drawn from the valleys. 



It seems probable that at the period of maximum giaciation 

 the relative amounts of precipitation on the northern and 

 southern sides of the St Elias mountains were much the same 

 as at present, and then as now by far the greater ice drainage 

 was toAvard the south. Some measure of the relative volume of 

 the ice streams flowing in the two directions may be obtained 

 from the relative amounts of moraine" material which they have 

 left. On the north, as already stated, there is no terminal 

 moraine— only a comparatively thin sheet of boAvlder clay. 

 South of the mountains, on the other hand, a deposit of morainal 

 . material at least several thousand feet in thickness Avas accumu- 

 lated on the sea bottom in front of the glacier and is now shoAvn, 

 according to Russell, in the recent uplift forming the Chaix hills. 



Connecting upon the map the points which have been de- 

 termined by various observers as the northern limit of the 

 glaciated area in the Yukon basin, the position of the Cordil- 

 leran ice sheet at the period of its greatest extension is approxi- 

 mately outlined. Striated rock surfaces Avere observed by Daw- 

 son on the Pelly down to the point at which it crosses the 136th 

 meridian and on the LcAves as far north as 61° 40'. Although 

 he does not regard these as strictly limiting points, still, in the 

 light of facts observed on the plateau southwest of the Pelly- 

 LcAves confluence, the former at least may safely be regarded as 

 such. McConnell and Russell considered the limit of giaciation 

 on the LcAves to be near the mouth of Little Salmon river, and 

 ' my OAvn observations led me to think it is at least as far north 



