•"11 PROCEEDINGS "I SEW Y<>UK MEETING. 



and occasionally, for the next 200 miles, sands, silts, and gravels Bimilar to those on the 



Porcupine il ■ it- bottom. Approaching 1 1 1 « • Stewart river, wide gravel terraces from 



30 i" LOO feet high border the river and recur at intervals all the way t" i bo Kink rapids 

 on Lewes river, below which point the bowlder clay, which has nol been seen since 

 leaving the Mackenzie, again makes it- appearance. Above this, ice groovings and 

 ings and all the other well-known marks of glaciation are everywhere evident. 

 I had m> opportunity of examining the plateau bordering the Yukon; but, judging 

 simply from the records of the ice age which the valley itself affords, it would appear 

 that the glacier which undoubtedly tilled the upper part of the valley of the Lewes 

 and moved northwards did n>>t descend below a point aboul 50 miles above the mouth 

 of the Pelly, or lat. 62° 50' N. Below this the deposits indicate a flooded valley, but 

 nothing else. 



B ore closing this paper ] should like to draw attention to a fact which may have 

 some bearing on the non-glaciated condition of p;irt of Alaska and the adjacent por- 

 tion of the North West territory of Canada, viz., that glaciers are unknown in the 

 Rocky Mountains north of the headwater- of the Athabasca, or about lat. 54° 2T. 

 North of this occasional patches of snow survive the summer in sheltered tmuks, hut 

 even these decrease in frequency with increasing latitude : and on the Peel river port- 

 age, in lat. »'»7 30' X.. the snow bad entirely disappeared hct'.ire the middle of July. 

 .\ -•.. in descending the Porcupine and ascending the Yukon, no snow was Been until 

 far up the Lewes, and no glaciers until the head water- of this stream were reached. 

 It follows from this that climatic changes which would extend the present glaciers 

 of the Bow and Saskatchewan far down their valley- might have little or no effect in 

 imposing glacial conditions on this more northern region. 



Geologk \i. Survey <>r Canada, December 24, 1889. 



The reading of tl.i- paper led t<> a continuation of the discussion on Alaska, 

 in which Alexander Winchell, W. M. Davis, I. < '. Russell, J. \V. Spencer, 

 ami ( l. K. ( rilberi participated. 



The next paper was entitled — 



POST-TERTIARY DEPOSITS OP MANITOB \ Wh I'll I. \ I >.l< >l \ I \< I TERRITOR1 E8 



OF NORTHWESTERN CANADA. 



r.V .i. B. TYRRELL. 



This communication was discussed by J. E. Mills, T. C. Chamberlin, N. 

 3. Shaler, W J McGee, J. W. Spencer, and Mr. Tyrrell. It is published 

 among the memoirs, forming pagi - 395 11" of this vol e. 



The substance of the next paper, read by Professor C. H. Hitchcock in 

 the absence of the author, is contained in the following abstract : 



\ MOB LINE OF Rl I RO< E88IOU I \ ONTA RIO. 



\;\ i;i.\ . Q. i ■KK.hK.KH K WEIGHT, 



[ Abstract \ 



This paper is principally occupied with the results of an investigation as t" the 

 character of the Oak Knolls in Whitchurch and King townships, York county, On- 



