350 THE GEOLOGY OF T.HE LABRADOR COAST. 



with the upheaval or the Sub-Apennines of Italy, or Alps 

 of Valais. 



Professor Dana, in his " Manual of Geology," states 

 further important distinctions, such as the rise of land in 

 the high latitudes which had not before taken place since 

 Palaeozoic times, ushering in the period of great glaciers, 

 and thus serving, over one half of the surface of the 

 globe, to further separate this epoch from the Tertiary, 



Another feature of this period is the great uniformity 

 of climate over broad, continental areas, and the wide 

 distribution in space of certain species most characteristic 

 of the Quaternary Formation, Such are the occurrence, 

 on both hemispheres, of the musk-ox, the Siberian mam- 

 moth (-£". primigenius), and, among marine mollusca, of 

 Leda arctica Gray, Sars (^portlandicd), which is now re- 

 stricted to the circumpolar seas. 



General Conclusions. — To account for all the facts 

 which have been developed above, we must assume, — 



I. That the northern portion of North America, that 

 is, the boreal and arctic regions, stood at a much higher 

 level above the sea than now. We have given good 

 evidence that it stood at least three hundred and sixty 

 feet above that level in Labrador. It would be safe to 

 assume that the coast line stood at an elevation not fall- 

 ing short of six hundred feet. While this increase in the 

 height of the land would not materially change the 

 physiognomy of the continent north of the St. Lawrence 

 River and Gulf, where the tableland rises abruptly from 

 the ocean as in the arctic regions ; it would effect a 

 great alteration in the distribution of dry land south of 

 the parallel of 50° N. Should all the present sea-bottom 

 lying within the limits of the depth of one hundred 



