154 PROF. E, HULL, LL.D., F.R.S., P.G.S., ON 



his great Avork still adheres to his original views, which find 

 support in the conclusions arrived at in the present paper. 

 FeAV will deny that, but for the Gulf Stream, the British 

 Islands and Northern Eiu'ope would now be subjected to 

 glacial conditions ; and with the aid of Professor Spencer's 

 researches I have attempted to show how such conditions 

 were brought about. 



Postscript. — Since the above Avas written, Mr. Warren 

 Upham, of the United States Geological Survey, has dealt 

 with this subject in an able paper communicated to the 

 Institute in the Session of 1890-7,* and corroborates gener- 

 ally the views of Prof. Spencer, and other American geolo- 

 gists, including Dana and Le Conte, regarding the former 

 great uprise of the continental lands at, or near the commence- 

 ment of the Glacial epoch; arriving at similar conclur-ions with 

 those of the author of this paper, but based mainly on the 

 view of the lowering of temperature due to such elevation. 

 In the paper here given to the Institute, I have endeavoured 

 to show how, in addition to the lowering of temperature clue 

 to elevation of land in the Northern Hemisphere, the deflec- 

 tion of the Gulf Stream must have also materially influenced 

 the climatic conditions. It need scarcely be stated that both 

 papers were written altogether independently of each other ; 

 but their agi'eement in the conclusions will be regarded as 

 confirmatory of the " epeirogenic " or " earth-movement " 

 hypothesis. 



The most able opponent of this hypothesis is Prof. James 

 Geikie, and I have re-read his elaborate communication to 

 this Institute,! dealing with this subject, in order to refresh 

 my memory as regards his views and arguments ; which 

 have also been dealt with by JMr. Warren Upham ; and as it 

 seems to me, in the main, successfully. J I cannot see, for 

 instance, upon what ground Prof. Geikie considers the 

 American uplift to have been long antecedent to the Pleisto- 

 cene epoch. Of course the uprise of the land around the 

 shores of the North Atlantic was gradual, and the accumula- 

 tion of snow and ice would also have been a very slow 

 process ; but both Spencer and Upham are agreed that this 

 uprise commenced with the close of the Pliocene period ; a 



* Upliam, " Causes of the Ice Age," Joxirn. Vkt. List., vol. xxix, p, 201 

 (1897). 



t Jhid., vol. xxvi. 



X Ibid., pp. 221 and 254, also vol. xxix, p. 237. 



