398 A JOURNEY IN BRAZIL. 
of a separate chapter. The reader will find occasional 
repetitions of facts already stated in the earlier part of 
the narrative ; but they are retained for the sake of giv- 
ing a complete and consistent review of the subject at 
this point of our journey, where it became possible to 
compare the geological structure of the Amazonian Val- 
ley with that of the southern provinces of Brazil and of 
those bordering on the Atlantic coast. 
THE existence of a glacial period, however much derided 
when first announced, is now a recognized fact. The 
divergence of opinion respecting it is limited to a ques- 
tion of extent ; and after my recent journey in the Ama- 
zons, I am led to add a new chapter to the strange history 
of glacial phenomena, taken from the southern 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 scien- 
tific 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 ex- 
tension 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, during the 
same epoch, be recognized sooner or later as part of a 
great series of physical events- extending over the whole 
globe. Indeed, when the ice-period is fully understood, 
it will be seen that the absurdity lies in supposing that 
climatic conditions so different could be limited to a small 
portion of the world's surface. If the geological winter 
