Terry.] 



74 [December 21, 



here, lie would say that there was evidence of a great disturbance, 

 even in this neighborhood, at the time in question. The tertiary beds 

 of Martha's Vineyard are tilted up at a high angle, and there are 

 facts indicating that the uplifting took place not far from the begin- 

 ning of the ice period. The strike of the beds suggests that the 

 agency was also submarine; that thus the waves of the Atlantic were 

 probably greatly heated, and the conditions furnished for immense 

 evaporation. 



The question raised in regard to the evidence of glacial agency in 

 Brazil, requires a moment's notice. As to the statement that the 

 extension of the glacier hypothesis to that region is one of the great- 

 est objections to it, he would merely say, that whether the extension 

 be justifiable or not, it in no wise militates against the existence of 

 ice agency in New England. As he had never visited the region, he 

 was not prepared to discuss features which can be adequately under- 

 stood only after the closest examination. The presumption, of 

 course, is that Professor Agassiz has only spoken after due considera- 

 tion, and that he is abundantly able to defend his view of the matter. 



The former occurrence of ice agency in the basin of the Amazons 

 being granted, it may be asked whether it were synchronous with the 

 existence of drift agency in North America. After all he could learn 

 on the subject, the observations thus far made seemed to him insuffi- 

 cient for the decision of the question whether the drift agency of the 

 northern hemisphere was simultaneous with that of the southern, or 

 subsequent to it. For that reason, while he might sometimes speak 

 of one set of cosmical agencies, and sometimes of another, he was 

 indisposed to say, because he did not know, just which prevailed ; 

 only that, under given circumstances, they were abundantly sufficient 

 for the production of the facts requiring an explanation. 



In respect to the assertion that, the bottom of Lake Superior being 

 lower than the surface of the ocean, ice could not have moved from 

 that basin seaward, he would say that the implied objection seems 

 to rest on a misapprehension of the condition of things during 

 the ice period. Let us remember that the ice, for instance, 

 on the north shore of the lake was probably from five to 

 ten thousand feet in thickness; that it was pressed by a portion 

 equally thick, if not thicker, adjoining it on the north, and this by 

 another and another ; that the basin, which was probably far more 

 shallow at the beginning of the ice period, would be filled with ice, 

 and greatly deepened, because of the immense force pressing from 



