THE PEAT CLISTASE. 



401 



referred to in previous reports and publications, but it may be repeated at this 

 time that the definite and abundant occurrence of Madura aurantiaca, Juni- 

 perus mrginiana, Quercus obtimloha, Quercus oblongifolia, Asimina triloba, 

 Chamaecyparis sphaeraidea, and Fraxinus guadrangukita points without ques- 

 tion to the prevalence of a much warmer climate than now prevails, while, on 

 the other hand, the equally abundant occurrence of boreal types at Scarborough 

 points to the existence of a colder climate at the time these deposits were laid 

 down. It is therefore clear that in the region of Toronto during Pleistocene 

 time there were at least two distinct periods, characterized, on the one hand, by 

 a climate equivalent to that of the middle United States at the present day, 

 and, on the other hand, a climate equivalent to that of northern Quebec and 

 Labrador. According to stratigraphical evidence obtained by Professor 

 Coleman, these changes followed the recession of the ice sheet in the order given, 

 from which we are to conclude that the climate of the Don Valley is now inter- 

 mediate between that of the first and second periods, approaching the former. 

 "On the other hand, again, the flora of Green's Creek and Besserer's, as also 

 that of Montreal, is practically identical with that now existing in the same 

 locaUties. It thus represents a climate colder than that of the Don period, 

 but somewhat warmer than that of the Scarborough period, but present 

 evidence does not enable us to ascertain if these deposits were laid down before 

 or after the Scarborough deposits. The following smnmaiy will probably 

 assist in conveying a clearer idea of the distinctive differences in the vegetation 

 of these three periods: 



Species. 



Abies balsamea 



Acer pleistocenicum 



" saccharinvun 



" spicatum 



Algae sp 



Alnus sp 



Asimina triloba 



Betula lutea 



Brasenia peltata 



Bromus ciliatus 



Carex aquatilis 



" magellanica 



" reticulata 



Chara alba 



Chamaecyparis sphaeroidea 



Crataegus punctata 



Cyperaceae sp 



Drosera rotundif olia 



Elodea canadensis 



Encyonema prostratum . . . , 



Equisetum limosum 



" acirpoides 



sp 



" sylvaticum 



Eriocaulon sp 



Fontinalis sp 



Fucus digitatus 



Fraxinus quadrangulata . . . . 



" sambucifolia 



" americana 



Don 



period, 



warm 



climate. 



X 

 X 



X 

 X 

 X 

 X 



Scar- 

 borough 

 period, 



cold 

 climate. 



Green's 

 Creek 



period, 

 mild 



climate. 



X 

 X 



X 

 X 

 X 



X 

 X 

 X 

 X 

 X 

 X 



X 



X 



