DARWIN ON ANCIENT GLACIERS. 343 



I found one with the lateral moraine quite 

 perfect, which Dr. Buckland did not see. Pray 

 if you have any communication with Dr. Buck- 

 land give him my warmest thanks for having 

 guided me, through the pubUshed abstract of 

 his memoir, to scenes, and made me under- 

 stand them, which have given me more de- 

 light than I almost remember to have experi- 

 enced since I first saw an extinct crater. The 

 valley about here and the site of the inn at 

 which I am now writing must once have been 

 covered by at least 800 or 1,000 feet in thick- 

 ness of solid ice ! Eleven years ago I spent a 

 whole day in the valley where yesterday every- 

 thing but the ice of the glaciers was palpably 

 clear to me, and I then saw nothing but plain 

 water and bare rock. These glaciers have 

 been grand agencies. I am the more pleased 

 with what I have seen in North Wales, as it 

 convinces me that my view of the distribution 

 of the boulders on the South American plains, 

 as effected by floating ice, is correct. I am 

 also more convinced that the valleys of Glen 

 Roy and the neighboring parts of Scotland 

 have been occupied by arms of the sea, and 

 very likely (for in that point I cannot, of 

 course, doubt Agassiz and Buckland) by gla- 

 ciers also. 



