1846 LETTER FROM DARWIN 85 



C. DARWIN TO A. C. RAMSAY. 



DOWN, FARNBOROUGH, 

 loth October (18 46). 



DEAR SIR Having just read your excellent Memoir on De- 

 nudation, I have taken the liberty to send you a copy of my volume 

 on South America, finding that we have discussed some related 

 questions. I wish I had profited by your Memoir before publishing 

 my volume. I see that we entirely agree on the sea's great power 

 compared with ordinary alluvial action, and likewise on the fre- 

 quency of grand oscillations of level, and on several other points. 

 If you had time to read parts of my volume, I should much like 

 to discuss with you many cases, such as my notion of subsidence 

 being necessary for the formation of high sea-cliffs, as inferred from 

 the nature of the sea's bottom off them; likewise the horizontal 

 elevation of the Cordillera as inferred from the sloping gravel 

 fringes in the valleys ; the non-horizontality of lines of escarpments 

 round old bays, etc. etc. I grieve to see how diametrically 

 opposite our views are (I being a follower of Lyell) on the prob- 

 ability of great and sudden elevations of mountain - chains ; I 

 cannot but think that you would have estimated existing forces 

 as more than 'petty,' and entertained some doubt about their 

 being 'conflicting,' had you inspected with your own eyes the 

 wide area of recently elevated and similarly affected districts in 

 South America. There is much which I could say on this head, 

 but I will not intrude on you. 



May I ask whether you do not admit Mr. Hopkins's views of 

 mountain-chains being the subordinate effects of fractures con- 

 sequent on changes of level in the surrounding areas ; and does 

 not all the evidence which we possess tend to show that widely- 

 extended elevations are slow, and may we not infer from this that 

 the formation of mountain-chains is likewise probably slow ? I can- 

 not see any difficulty, after a line of fracture has been once formed, 

 in fluidified rock being pumped in by as many strokes, as it is 

 pumped out in a common volcano, and yet producing a sym- 

 metrical effect. But I much fear that I have cause to apologise 

 for having written at such unreasonable length ; the interest excited 

 in me by your Memoir must plead my excuse, and trusting that 

 you will forgive the liberty I have taken, I remain, dear sir, yours 

 faithfully, C. DARWIN. 



C. LYELL TO A. C. RAMSAY. 



MY DEAR SIR I have just been reading with great pleasure 

 your admirable and well-written essay on the Denudation of South 



