226 WARREN UPHAM, ESQ., ON CAUSES OF THE ICE AGE. 



believe it, certainly. I observed in the valley of Aosta, on the 

 south side of Mont Blanc, where I went to find some of these 

 enormous boulders, the most distinct marks of striee, as they are 

 called, made on the rocks that flank the valley, and they were so 

 fresh that I said to myself, " It is impossible that these marks 

 could have been made 50,000, 40,000, or 30,000 years ago." They 

 looked to me as if they had not been made more than 100 years ; 

 and I made exactly the same observation in regard to the extensive 

 valley that leads from Reichenbach up to the Gemmi Pass. 

 There are portions of that valley, where the guide books point out 

 thei'e are strong marks of glaciation along the rocks and polished 

 surfaces, and I venture to saj that nobody could see those marks 

 and believe that they were 50,000 years old, or one-fifth part of 

 that age. I made some observations also in regard to some glacial 

 striae on what are called the glacial rocks in Cumberland, on the 

 plain that lies not far from the church at Ambleside. 



Professor Hull. — Yes, I think I was the first to describe it, 

 about thirty years ago ; it is reproduced in Lyell's Antiquity of 

 Man — from my original drawing in the Edinburgh New Philoso- 

 phical Journal. 



Mr. Joseph Brown, C.B. — It is not possible to suppose that the 

 marks are anything like 20,000, or even 10,000 years old. Rocks 

 wear away too fast for that, although some of them are the hardest 

 things in Nature. For that reason, I cannot bring myself to 

 believe that the Ice Age was so far back as some geologists 

 consider. I have held my mind in suspense all the time I have 

 been investigating the question, some fifty or sixty years, and I 

 cannot bring myself to believe that these marks and indications 

 are anything like so old as they are reputed to be. Although I 

 consider the paper which has been read to-day has thrown more 

 light on this very difficult question, as to the rocks and the cause 

 of the Ice Age, and how many thousands of years back it dates, 

 than any paper I have read for a long time, yet I find myself 

 unable to agree with one suggestioQ made by the author, whose 

 opinions on the subject are worth a great deal more than mine, 

 (for I do not put forward my observations as more than those of 

 an amateur) , and it is this : — I heard the Professor say that these 

 great submerged valleys that have been eroded outside the edge 

 of the great North American Continent, as well as some that 

 appeared to be eroded outside the African Continent, must have 



