17% 
this wide range because of any perfection of seed dissemination, nor 
because of occasional means of transportation. It has more probably been 
brought about by a former connection of these separate regions, Making 
them practically continuous. Such practical continuity may have been 
secured by means of the flooded rivers and swollen lakes of the Champlain 
period. This is not offered as a solution of all of the problems of plant 
distribution, but in the firm belief that in many of these problems the 
solution is to be sought in former physical conditions. 
It was the original intention that the present paper should also include 
a discussion of the species restricted to the southern tiers of cGounties, but 
the time required to work our former shore lines and water-levels for that 
region was too great. The preliminary work, however, seemed to indicate 
confirmation of the conclusions indicated in this paper. 
12—4966 
