GEOLOGY. 267 



elevated into a mountainous range of not less than 10,000 feet in 

 height ; a conclusion inadmissible, on account of the entire absence of 

 all independent geological evidence in support of it. The hypothesis 

 of case 3, Mr. Hopkins rejects for a similar reason. Case 4 is then 

 discussed at length. It is shown that glaciers of the required magni- 

 tude would in that case exist in the region of Western Europe, if in 

 addition to the absence of the gulf stream we suppose the existence of 

 a cold current from the north of a moderately refrigerating influence. 

 This latter current, however, might not be essential. The entire 

 diversion of the present gulf stream into some other channel, which is 

 required by this view of the subject, would be the necessary conse- 

 quence of that submersion of the North American continent, of which 

 we have such conclusive evidences during the glacial period ; for in 

 such case the current which sets into the Gulf of Mexico would mani- 

 festly continue in its north-westerly direction along the present valley 

 of the Mississippi and the range of the Rocky Mountains to discharge 

 itself into the Atlantic Ocean. This would correspond to the glacial 

 period on this side the Atlantic ; but along the new course of the 

 gulf stream there w r ould be a much w r armer climate than at present, 

 and that such a climate has there existed at a recent geological 

 epoch seems to be abundantly proved by vegetable remains which 

 have been found between Hudson's Bay and the Rocky Mountains, 

 precisely in the line which the warmer current would take. 



A subsidence of the American Continent, of less than 2,000 feet 

 would render the ocean continuous from the Apalachian chain, on the 

 east, to the Rocky Mountains on the west, and there seems reason to 

 believe that the subsidence may possibly have attained to a consider- 

 ably greater amount. Now, it is manifest that the gulf stream is 

 reflected in a north-easterly direction across the Atlantic, by the con- 

 tinent of North America, which arrests the north-westerly course by 

 which the current reaches the Gulf of Mexico. But when that con- 

 'tinent was submerged, as above supposed, the current would necessa- 

 rily continue its north-westerly course, and probably along the foot of 

 the Rocky Mountains directly into the Arctic Sea. This is the man- 

 ner in which it is conceived the gulf stream was diverted from the 

 shores of Western Europe. This diversion of the current is not to 

 be regarded as a mere hypothesis adopted to account for any particu- 

 lar tact, but as a necessary consequence of that submergence of the 

 North American continent. 



Again, if this enormous current discharged itself into the Arctic 

 Sea, it would seem extremely improbable that it should not give rise 

 to some great determinate counter-current out of that sea. Now it 

 appears highly probable that a considerable tract of land must have 

 existed at the period of which we are speaking in the present region 

 of north-eastern America, and Greenland. If this were the case, the 

 only practicable outlet for a great current from the Arctic Sea would 

 be across the submerged portion of northern Europe, or along the 

 present North Sea, between Greenland and Norway ; for the passage 

 through Behring's Straits, even with a considerable subsidence of the 



