18 THK ICK A(iK F\ CANADA. 



AV(! iiiav, tlu'iuforo, sut'cly assuiiii' that tlio I'cfiincration 

 iiulicatetl l)y these, plants would plaeo the royiou hnrderiiiL; 

 the Ottawa in nearly the same jHisition with that of the 

 south coast of Lahrador frontinj^on the uulf of St. [.awrence 

 at pre.sent. The aUsenee of all tla^ nioic aretie si)eeies 

 oceurrint,' in Labrador, should j»erha]is induce us to infer 

 a somewhat more mild elimate than this [and also indi- 

 cates the prohahle existence of the arctic llora to the 

 northward throughout the pleist(»cene ]terio(l]." 



"The moderate amount of refrij^'eration thus required, 

 would, in my opinion, accord very well with the ])rolial)le 

 conditions of climate deduciljle from the circumstances in 

 which the fossil plants in ([uestion occur. At the same time 

 when they wei'e deposited, the sea Mowed uj) the Ottawa 

 valley to a height of 2U0 to 400 feet al>ove its i>resent 

 level, and the valley of the St. Lawrence was a wide arm 

 of the sea, open to the arctic current. Uiuler these 

 conditions the immense (juantities of drift ice from the 

 northward, and the removal of the great heating surface 

 now presented hy the low lands of Canada and New 

 England, nuist have given for the Ottawa coast of that 

 period a summer temperature very similar to that at 

 present experienced on the Labrador coast, and with this 

 conclusion the marine remains of the Leda clay, as well 

 as the few land moUusks whose shells have been found in 

 the beds containing the ])lants, and which are species still 

 occurring in Caiuula, ])erfectly coincide. 



"The climate of that jjortion of Canada above water at 

 the time when these plants were imbedded, may safely be 

 assumed to have been colder in sunnuer than at present, 

 to an extent equal to about 5° of latitude, and this 

 refrigeration may be assumed to correspond with the 

 requirements of the actual geographical changes implied. 



