420 Canadian Record of Science. 



marine origin of the Erie clays, so widely distributed in 

 Ontario, I showed that there was some ground for the con- 

 clusion that the Alpine flora of the White Mountains of 

 New England, the boreal colonies of plants on the headlands 

 of Lake Superior, the sea-shore species now spread around 

 the Great Lakes, and the fossil plants of the Leda clays near 

 Ottawa had, probably, all — with regard to their present 

 localities — a contemporaneous origin, and were likewise 

 contemporaneous with the formation of the Erie clays. 

 Now, when it is observed that a very large majority of these 

 species, including all recognized in the Leda clays excepting 

 JPotentilla Canadensis and Populus balsamifera, are also found 

 in Europe, the conclusion is inevitable that this interming- 

 ling of the floras of the two continents of America and 

 Europe, must have taken place at or prior to the formation 

 of the Leda clays, unless Eastern Canada is to be regarded 

 as the centre of dispersion, and that the general flora of the 

 two continents can date back its origin to or anterior to 

 that time. The identity in species in Europe and America 

 is not, however, confined to certain of the plants hitherto 

 referred to, and to certain of the Arctic plants. There are 

 numerous others of temperate range not found in Japan, 

 which are common to the two continents of America and 

 Europe. Many of them have a general range from the 

 Atlantic to the Pacific, others again do not cross the Eocky 

 Mountains, whilst some, among them the following, do not 

 extend westward beyond Ontario and Quebec : — 



Drosera longifolia, L., (in Manitoba also.) 



Sagina procumbens, L. 



Spergularia rubra, Presl. 



Potentilla argentea, L. 



Circgea Lutetiana L. 



Myriophyllum verticillatum, L. 



Scrophularia nodosa, L. 



Veronica officinalis, L. 



Stachys palustris, L. 



Salsola Kali, L. 



Typha angustifolia, L. 



Naias flexilis, Rostk. 



Potamogeton gramineus, L. 



