PHYSICAL HISTORY OF THE 
VALLEY OF THE AMAZONS. 
YEAR or two ago I published in the 
II “ Atlantic Monthly,” as part of a series 
of geological sketches, a number of articles on 
the glacial phenomena of the Northern hemi¬ 
sphere. To-day I am led to add a new chapter 
to that strange history, taken from the South¬ 
ern hemisphere, and even from the tropics 
themselves. 
I am prepared to find that the statement 
of this new phase of the glacial period will 
awaken among my scientific colleagues an 
opposition even more violent than that by 
which the first announcement of my views on 
this subject was met. I am, however, willing 
to bide my time; feeling sure that, as the 
theory of the ancient extension of glaciers in 
Europe has gradually come to be accepted by 
geologists, so will the existence of like phe¬ 
nomena, both in North and South America, 
* 
