152 GEOLOGY [Chap. IX 



Letter 501 open for news which would have interested you ; but I have 

 not forgotten you. Two days after receiving your letter, 

 there was a short leading notice about you in the Gardefiers' 

 Chronicle ; l in which it is said you have discovered a noble 

 crimson rose and thirty rhododendrons. I must heartily 

 congratulate you on these discoveries, which will interest the 

 public ; and I have no doubt that you will have made plenty 

 of most interesting botanical observations. This last letter 

 shall be put with all your others, which are now safe together. 

 I am very glad that you have got minute details about the 

 terraces in the valleys : your description sounds curiously like 

 the terraces in the Cordillera of Chili ; these latter, however, are 

 single in each valley ; but you will hereafter see a description 

 of these terraces in my Geology of S. America? At the 

 end of your letter you speak about giving ,up Geology, but you 

 must not think of it ; I am sure your observations will be 

 very interesting. Your account of the great dam in the 

 Yangma valley is most curious, and quite full ; I find that I 

 did not at all understand its wonderful structure in your 

 former letter. Your notion of glaciers pushing detritus into 

 deep fiords (and ice floating fragments on their channels), is 

 in many respects new to me ; but I cannot help believing 

 your dam is a lateral moraine : I can hardly persuade myself 3 

 that the remains of floating ice action, at a period so 

 immensely remote as when the Himalaya stood at a low level 

 in the sea, would now be distinguishable. Your not having 

 found scored boulders and solid rocks is an objection both to 

 glaciers and floating ice ; for it is certain that both produce 

 such. I believe no rocks escape scoring, polishing and 

 mammillation in the Alps, though some lose it easily when 

 exposed. Are you familiar with appearance of ice-action ? 

 If I understand rightly, you object to the great dam having 



1 The Gardeners' Chronicle, 1849, p. 628. 



2 Geological Observations, pp. 10 et passim. 



3 Hooker's Himalayan Journals, Vol. II., p. 121,1854. In describing 

 certain deposits in the Lachoong valley, Hooker writes : " Glaciers 

 might have forced immense beds of gravel into positions that would 

 dam up lakes between the ice and the flanks of the valley" (p. 121). 

 In a footnote he adds : " We are still very ignorant of many details of 

 ice action, and especially of the origin of many enormous deposits which 

 are not true moraines." Such deposits are referred to as occurring in 

 the Yangma valley. 



