WOODWORTH: GEOLOGICAL EXPEDITION TO BRAZIL AND CHILE. 12] 
If one reads Chapter X on the Plains and valleys of Chile in Dar- 
win’s Geological observations, he will find the author convincing 
himself that the sea rather than the rivers now coming out of the 
Andes is accountable for nearly every detail of the land form,— not 
only the passes in the mountains and the valleys sculptured in the 
mountain mass but also the plains of waterworn detritus particularly 
where rounded pebbles are found. 
This statement tallies with the general belief of the school of 
geologists of the period in which Darwin formed his concepts. It was 
naturally easy for him to admit terraces of any origin and marine 
shells on the surface at lower levels along the coast of Chile as evidence 
of elevation when he had found to his own satisfaction that the sea 
had beaten against the high Andes where no recent marine shells are 
found. ‘This much is necessary for the reader to understand in weigh- 
ing the conclusions which may be presented concerning the elevation 
of the coast of Chile. 
It is only just to Darwin, however, to show from his own writings 
how he abandoned the views he entertained concerning topographic 
signs of elevation on the coast of South America when in later years 
similar problems came to his attention in the British Islands. 
Darwin (Francis Darwin, 1903, 2, p. 191) wrote Lyell in 1861,— 
“T return Jameson’s capital letter. I have no comments, except to 
say that he has removed all my difficulties, and that now and for 
evermore I give up and abominate Glen Roy and all its belongings. 
It certainly is a splendid case, and wonderful monument of the old 
ice period. ... How many have blundered over those horrid shelves!” 
Again in 1868, Darwin (Francis Darwin, 1903, 2, p. 211) wrote 
Croll,— “I was formerly a great believer in the power of the sea in 
denudation, and this was perhaps natural, as most of my geological 
work was done near sea-coasts and on islands. 
“But it is a consolation to me to reflect that as soon as I read Mr. 
Whittaker’s paper on the escarpments of England, and Ramsay and 
Juke’s papers, I gave up in my own mind the case; but I never realized 
the truth until reading your papers just received. How often have 
I speculated in vain on the origin of the valleys in the chalk platform 
round this place, but now allis clear.” Still he clung to his interpreta- 
tion of terraces and of shells on the surface in South America. As late 
as 1872, Darwin wrote Lyell (Francis Darwin, 1903, 2, p. 164-165),— 
“It seems to me very cool in Agassiz to doubt the recent upheaval 
of Patagonia, without having visited any part of it; and he entirely 
misrepresents me in saying that I infer upheaval from the form of the 
land, as I trusted entirely to shells embedded and on the surface. 
