172 THE CANADIAN NATURALIST. P la y 



Hudsonia ericoides, Linn. Euphorbia polygonifolia, Linn. 



II. tomentosa, Xutt. Xaias major, All. 



Hibiscus moscheutos, Linn. Ruppia maritima, Linn. 



Lathyrus maritimus, Bigel. Triglochin maritimum, Linn. 

 Atriplex hastata, Linn. T. palustre, Linn. 



Salicornia herbacea, Linn. Scirpus maritimus, Linn. 



Polygonum avicnlare, Linn. Galamagrostis arenaria, Loth. 



var. httorale, Link. Leptochloa fascicularis, Gray. 

 Hordcum jubatum, Linn. 



It is to be observed that some of these plants have a very 

 extended inland range, whilst others are apparently distributed over 

 very limited areas. Hudsonia tomentosa, Lathyrus maritimus, 



and Triglocltu/ maritimum are, perhaps, the most widely diffused. 

 It is conceived that this peculiar distribution owes its origin to 

 successive changes in the physical aspect of the province during 

 the post-pliocene epoch, and the gradual adaptation of the plants 

 to the new conditions in which they were, by force of circumstances, 

 placed; and further, that these plants indicate the probable 

 existence of a much more extensive maritime flora which flourished 

 on the ocean shores during this epoch. I have already briefly 

 detailed my views on the subject in this journal. I may, however, 

 here explain, that it has not yet been satisfactorily established, 

 what in post-pliocene times were the conditions of land and water 

 in what is now known as Western Canada. The precise age, 

 and the marine or lacustrine origin of the Erie clays, which are 

 largely developed there, are yet involved in some uncertainty from 

 the absence of any fossil evidence; nor is it yet known what 

 relations they bear to the marine sands and clays of Eastern 

 Canada, although they may have been contemporaneously de- 

 posited. If, however, I am correct in referring the origin of the 

 distribution of the inland maritime flora to the post-pliocene epoch, 

 it will furnish an argument for the marine character of such 

 deposits as are coeval with those of the eastern sections of the 

 province referable to this epoch. If the Great Lakes were in 

 these distant and yet comparatively recent times, bodies of salt- 

 water, or if they were united into one vast inland sea, as, judging 

 from geological evidence, was probably the case, we can readily 

 account for the migration of the sea-shore species along the coasts. 

 And if these seas or united seas gradually became fresh-water. 

 it docs not require much stretching of the imagination to picture 

 the struggle for life which must have taken place among these 

 wanderers from the ocean coast, in consequence flf. the gradual 



