76 ROYAL SOCIETY OF CANADA 



the entire collection, seems to point to the local abundance of the tree. 

 Like the larch, it is a well-known element of thé Don flora, while its 

 somewhat extended range in latitude does not permit us to draw final 

 conclusions as to climatic conditions, except as it is associated with other 

 types of more pronounced adaptation. 



Eeference to previous summaries ^ will show that the majority of 

 the plants represented in the present collection are characteristic of 

 the warmer climate of the Don period, while only one — Larix americana 

 — is also characteristic of the Scarborough period, and one^ — Vallisneria 

 spiralis — is exchtsively known through former collections to the mild 

 climate of the Green's Creek period. Of the two new representatives 

 of the flora, both are quite compatible with a mild or even warm climate, 

 and therefore offer no evidence in opposition to previous conclusions 

 respecting the climate of the Don period. 



^ Kept. B.A.A.S., Bradford, 1900, Pleist. Flora & Fauna, p. 1. 



