274 The Founders of Geology LECT. 



inenon, but must have resulted from some general lowering 

 of temperature. He coupled with this deduction certain 

 theoretical statements regarding former climates and faunas, 

 which have not been supported by subsequent research. 



The main conclusions which the Swiss naturalist drew, 

 so greatly interested him that he spent part of five suc- 

 cessive summers investigating the vestiges of the old 

 glaciers, and the operations of those of the present time. 

 He convinced himself that the great extension of the ice 

 was connected with the last great geological changes on 

 the surface of the globe, and with the extinction of the 

 large pachyderms, whose remains are so abundant in 

 Siberia. He believed that the glaciers did not advance 

 from the Alps into the plains, but rather that ice once 

 covered all the lower grounds, and finally retreated into 

 the mountains. 



Having arrived at these conclusions from studies in his 

 native country, Agassiz was naturally desirous to see how 

 far his views could be tested or confirmed in a region far 

 removed from any existing glaciers. Accordingly, in the 

 year 1840, three years after his address at Neufchatel, he 

 had an opportunity of visiting Britain, and took advantage 

 of it to examine a considerable part of Scotland, the north 

 of England, and the north, centre, west, and south-west of 

 Ireland. The results of this investigation were of remark- 

 able influence in the progress of glacial geology. Agassiz 

 demonstrated the identity of the phenomena in Britain 

 with those in Switzerland, and claimed "that not only 

 glaciers once existed in the British Islands, but that large 

 sheets (nappes) of ice covered all the surface." 1 



1 Proc. Geol. Soc. vol. iii. (1840), p. 331. 



