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XXXV. On the Erosion of Valleijs and Lakes ; a Reply to Sir 

 Roderick Murchison's Anniversary Address to the Geogra- 

 phical Society. By A. C. Ramsay, F.R.S.* 



AFTER the publication of my memoir "On the Glacial 

 Origin of certain Lakes in the Ice-worn regions of Europe 

 and North America," several eminent British and Continental 

 geologists, and some other persons who have only a general 

 literary acquaintance with physical geology, did me the honour, 

 in special memoirs, or in letters in newspapers, to express opi- 

 nions that my views were deserving of the strongest opposition. 

 To none of these opponents have I heretofore made any^ reply, 

 and some of them, I found, were dealt with by men who met 

 their arguments more ably perhaps than I could have done 

 myself. Besides, I considered that if my theory, as I believe, 

 be true, it would be sure in the long run to make its way just 

 in the slow and steady manner it seems to me to be now doing. 

 We all profess to appeal to nature, and "in nature there is no 

 opinion; there is truth in everything that is in nature; and in 

 man alone is error." To those who are not geologists in any 

 practical sense it would never occur to me to reply. Physical 

 geology, in the true meaning of the term, does not exist without 

 a thorough practical acquaintance with, and experience of, rocks 

 of all kinds on a large scale. The man who merely wanders 

 about a country and looks curiously at rocks, without a long 

 course of severe training, has no more scientific right to form a 

 definite opinion as to the causes that brought about the external 

 configuration of the land than the father of a family would have 

 to decide questions in comparative anatomy, because for half 

 his life he had daily carved beef, mutton, pork, fowls, and fish. 



Of late, however, an exceedingly authoritative protest against 

 my theory has been entered by Sir Roderick Murchison, in his 

 Anniversary Address to the Geographical Society, — an address 

 issued indeed to the geologists of Europe ; for the portion that 

 bears upon icy phenomena has been printed separately for special 

 distribution. It would almost be uncourteous on my part silently 

 to pass over the remarks of one who in his ow r n person has 

 attained the highest honours in the Geological and the Geogra- 

 phical Societies, and who is besides my oldest living geological 

 friend. " As a geologist, with wide experience, the President of 

 the geographers clearly states his conviction "f that my theory 

 of the origin of certain lakes and other theories of denudation 

 connected therewith, are so opposed to obvious facts, that, if 

 his conviction be well founded, the wonder seems to me that 



* Communicated by the Author. 



t Geological Magazine, No. 3, p. 127. 



