1867.] DRUMMOND — DISTRIBUTION OF PLANTS. 1 To 



change in at least one of those conditions, hitherto so apparently 

 es.sential to their very existence. As year followed year, and the 

 lakes became imperceptibly more fresh, successive individuals 

 of some of the species would, as it were insensibly, become more 

 and more reconciled to the new conditions, whilst, perhaps, 

 most of the species would gradually diminish in both numbers 

 and luxuriance, and finally, unable to perform those functions 

 necessary for their reproduction, would die, and thus completely 

 disappear from the lake coasts. As the lakes receded to their 

 present limits, the survivors, lured by the presence of the waters, 

 would follow, leaving, however, some of their number around the 

 saline springs of New York State and elsewhere. These sur- 

 vivors probably constitute a more hardy race than their fellows on 

 the ocean coast. This would seem to be illustrated by the more 

 northern inland range of some, the extended diffusion along the 

 lake margins of others, and the adaptation of all to new 

 conditions. 



These inland maritime plants have only as yet been detected on 

 or near the shores of broad lakes, and extensive bays, on the 

 borders of large swamps, or in the immediate vicinity of salt 

 springs and •• salt licks, " showing the marked preference which 

 these little ramblers still retain for the neighbourhood of saline 

 waters or for homes near the lake or bog margin, in which the saline 

 element alone is wanting to render complete. It is further to be 

 observed that the greatest number of species exist around, or at 

 smaller sheets of water, not far from the shores of lake Ontario, 

 the lake which, of all our inland, fresh-water seas, is much the 

 nearest to, in fact, almost adjoins what formed in post-pliocene 

 times, the ocean coast, and to the shores of which the first migra- 

 tion of sea-shore plants was probably effected. 



The animal kingdom affords illustrations of a distribution 

 analogous to that indicated by these little inland maritime plants. 

 Dr. Leconte has recognized upon the north shores of Lake 

 Superior, insects of a sea-shore type ; and in fresh-water lakes in 

 Norway have been observed two marine crustaceans whose 

 presence is attributed to a submergence and subsequent rise of 

 the land during the post-tertiary epoch, and a change in the 

 conditions of the waters of the lake from a state of saltness 

 to that of freshness, which these species survived. 



There is a probability that many existing species of plants in 

 Canada can date their period of creation as far back as t lie post- 



