1S46-1878] MI 1 I I.i VNEOl 



To J. D. Dana l*u« 561 



Down, Dec. 5th, 184';. 



I have not for some years been so much pleased as I have 

 just been by reading your most able discussion on coral reefs. 

 I thank you most sincerely for the very honourable mention 

 you make of me. 1 This clay I heard that the atlas has 

 arrived, and this completes your munificent present to me. 

 I have not yet come to the chapt< r on sub idence, and in that 

 1 fancy we shall disagree, but in the descriptive part our 

 agreement has been eminently satisfactory to me, and far 

 more than I ever ventured to anticipate. I consider that now 

 the subsidence theory is established. I have read about half 

 through the descriptive part of the Volcanic Geology* (last 

 night I ascended the peaks of Tahiti with you, and what 

 I saw in my slant excursion was most vividly brought before 

 me by your descriptions), and have been most deeply interested 

 by it. Your observations on the Sandwich craters strike mc 

 as the most important and original of any that I have read 

 for a long time. Now that I have read yours, I believe 1 saw 

 at the Galapagos, at a distance, instances of those most 

 curious fissures of eruption. There are many points of resem- 

 blance between the Galapagos and Sandwich Islands (even 

 to the shape of the mound-like hills) — viz., in the liquidity 

 of the lavas, absence of scoria-, and tuff-craters. Man)- of 

 your scattered remarks on denudation have particularly 

 interested mc ; but I sec that you attribute less to sea ami 

 more to running water than I have been accustomed to do. 

 After your remarks in your last very kind letter I could not 

 help skipping on to the Australian valleys, 3 on which your 

 remarks strike mc as exceedingly ingenious and novel, but 

 they have not converted me. I cannot conceive how the great 

 lateral bays could have been scooped out, and their sides 

 rendered precipitous by running water. 1 shall go on and 

 read every word of your excellent volume. 



1 United States Exploring Expedition during the Years 1S39 42 

 under the Command of Charles Wilkes, U.S.N. Vol. X.. & .. ; . by 

 J. D. Dana, 1849. 



* Part of Dana's Geology is devoted to volcanic action. 



s Ibid., pp. $2,6etseq.; " The Formation of Valleys, etc, in Now South 

 Wales." 



