154 
PHYSICAL HISTORY OF THE 
during the same epoch, be recognized sooner 
or later as part of a great series of physical 
events extending over the whole globe. In¬ 
deed, when the ice-period is fully understood, 
it will be seen that the absurdity lies in 
supposing that climatic conditions so intense 
could he limited to a small portion of the 
world’s surface. If the geological winter ex¬ 
isted at all, it must have been cosmic; and it 
is quite as rational to look for its traces in the 
Western as in the Eastern hemisphere, to the 
south of the equator as to the north of it. 
Impressed by this wider view of the subject, 
confirmed by a number of unpublished inves¬ 
tigations which I have made during the last 
three or four years in the United States, I 
came to South America, expecting to find in 
the tropical regions new evidences of a bygone 
glacial period, though, of course, under differ¬ 
ent aspects. Such a result seemed to me the 
logical sequence of what I had already ob¬ 
served in Europe and in North America. 
On my arrival in Rio de Janeiro, — the port 
at which I first landed in Brazil, — my atten¬ 
tion was immediately attracted by a very pe¬ 
culiar formation, consisting of an ochraceous, 
