122 GEOLOGY [Chap. IX 



Letter 482 Alpine insects ; but he is wrong in thinking that there is any 

 necessary connection of tropics and large insects — videlicet — 

 Galapagos Arch., under the equator. Small insects swarm in 

 all parts of tropics, though accompanied generally with large 

 ones. 



Thirdly, he appears influenced by the absence of newer 

 deposits on the old area, blinded by the supposed necessity of 

 sediment accumulating somewhere near (as no doubt is true) 

 and being preserved — an example, as I think, of the common 

 error which I wrote to you about. The preservation of 

 sedimentary deposits being, as I do not doubt, the exception 

 when they are accumulated during periods of elevation or of 

 stationary level, and therefore the preservation of newer 

 deposits would not be probable, according to your view that 

 Ramsay's great Palaeozoic masses were denuded, whilst slowly 

 rising. Do pray look at end of Chapter II., at what little I 

 have said on this subject in my S. American volume. 1 



I do not think you can safely argue that the whole 

 surface was probably denuded at same time to the level of 

 the lateral patches of Magnesian conglomerate. 



The latter part of the paper strikes me as good, but 

 obvious. 



I shall send him my S. American volume, for it is curious 

 on how many similar points we enter, and I modestly hope 

 it may be a half-oz. weight towards his conversion to better 

 views. If he would but reject his great sudden elevations, 

 how sound and good he would be. I doubt whether this 

 letter will be worth the reading. 



Letter 483 To C. Lyell. 



Down [Sept. 4th, 1849]. 

 It was very good of you to write me so long a letter, 

 which has interested me much. I should have answered it 

 sooner, but I have not been very well for the few last days. 

 Your letter has also flattered me much in many points. I 

 am very glad you have been thinking over the relation of 

 subsidence and the accumulation of deposits ; it has to me 

 removed many great difficulties ; please to observe that I 



1 The second chapter of the Geological Observations concludes with a 

 Summary on the Recent Elevations of the West Coast of South America, 



(P- 53). ' 



