in the Pleistocene and Post- Pleistocene. 17 



In his first publication Professor Fernald had given much 

 weight to the suggestions derived from Penck and Daly, — that 

 the ice of the continental glaciers abstracted so much water 

 from the ocean that an emergence would be expected of part 

 of the continental shelves. But against this cause as an agent 

 operative in this instance it is to be noted that in direct propor- 

 tion as the climate became warmer and the ice withdrew such 

 an emergence would have disappeared. The character of the 

 flora suggests, however, that the migration to the present 

 isolated localities must have taken place during a period of 

 climate even warmer than the present and at a time after the 

 ice sheets had given up their water. This aspect tends to rule 

 out the availability of the hypothesis that emergence was con- 

 trolled only by the level of the ocean water as controlled in 

 turn by glaciation. In response to questions by the writer 

 regarding the indications of the plants as to the climatic con- 

 ditions which would favor their migration and successful com- 

 petition with other floras, Professor Fernald, under date of 

 January 15, 1915, wrote a letter, which because of its great 

 value on the problem of recent crustal movements is quoted 

 here nearly entire. 



Botanical Evidences. .-■»- A Preliminary Statement of Results 

 of Studies on the Northeastward Distribution of the Coastal 

 Plain Flora, by M. L. Fernald : 



The question you raise, of the probable period and climatic 

 conditions of the migration of southern coastal plain plants to 

 Newfoundland, is one on which there is now accumulating a vast 

 amount of evidence. Since I published a preliminary statement 

 of the case I have had parts of two seasons in Newfoundland 

 where I secured much more similar material, a season divided 

 between Prince Edward Island and the Magdalen Islands, which 

 have a flora much more southern than boreal, with many New 

 Jersey Pinebarren species, a summer on Cape Cod and Black 

 Island, where there are still larger proportions of such cases. 

 One of my research students, Mr. Harold St. John, has spent a 

 season on Sable Island, getting evidence in the same line, and 

 another season on the Magdalen Islands, and he is now working 

 on the results as his doctor's thesis. Another graduate student, 

 Mr. Sidney F. Blake, has spent a season on Northumberland 

 Strait and the sands of northeastern New Brunswick, where he 

 secured further material upon which his thesis will be based. 



Briefly, we have in southern Newfoundland (south of the North 

 Peninsula) a large number of species of southern origin, some 

 even of tropical affinity. Further, on the shores of Dawson's 

 warm Acadian Bay (see Dawson, Canadian Nat., ser. 2, vii, p. 277, 

 1875), including the region from Cape Breton to the south side 

 of Baie des Chaleurs, i.e., eastern Nova Scotia, eastern New 



Am. Jour. Sci. — Fourth Series, Vol. XL, No. 235. —July, 1915. 



. 



