IllSTOKR'AL XOTIt'KS. 17 



puiiits with tlit'sc tlicitrisls, we can (lisi)eiiso all()<!;etlu'r 

 with tlu! iMtiteiitous chiin^fos in physical ^a'onrajihy involved 

 ill their \icws, and which arc iii»t iiecossary to explain 

 any <il" the other i)henoniena." 



The adih'uss then proceeds to deal with these ])oints in 

 the manner to lie stalecl in a snhstMpient chaptei'. 



Two years later, in l(S(i(), I prcjtared an account of all 

 that was known \\\) lo that date of tlrj fossil ])lants of the 

 niid-])leistocene IhmIs, the Leda clay of the Ottawa and 8t. 

 Lawrence valleys, e(|uivalent in a<i;e to the so-t-alled inter- 

 ylacial heds of western Canada. In this paper the 

 followini;- summary is *;iven of the climatal conditions 

 indicated : — 



" Xone of the ])lants from these mid-^tilacial beds is 

 projierly arctii' in its (Hsliihiition, ami the assemblage 

 may Ix; charactmized as a selection frt)m tiie ])resent 

 Canadian flora of some of the more hardy species having 

 the most northern range. (Ireen's Creek is in the central 

 part of Canada, near to the parallel of 4() , and an acci- 

 dental selection from its present llora, though it might 

 contain the same S[)ecies found in the nodules, W(nild 

 certainlv include with these, or instead of ."ome of them, 

 more southern forms. More especially the balsam poi)lar, 

 though that tree occurs ])lentiful!y on tlie Ottawa, would 

 not be so [)redonnnant. IJul such an assemldage of drift 

 plants nnght be furiushed l)y any American stream 

 llowing in the latitude of 50^ to oi")" north. If a stream 

 tlowing to the north, it might deposit these plants in still 

 more northern latitudes, as the McKenzie river does 

 now. If llowing to the south, it might dei)osit them to 

 the south of oO'. In the case of the Ottawa, the plants 

 could not have been derived from a more southern 

 locality, nor probably from one very far to the north. 

 3 



