VALLEY OF THE AMAZONS. 
zonian deposits are due to the immense size 
of the basin enclosed, and the identity of the 
materials contained in it. 
A glance at any geological map of the world 
will show the reader that the Valley of the 
Amazons, so far as any attempt is made to 
explain its structure, is represented as contain¬ 
ing isolated tracts of Devonian, Triassic, Ju¬ 
rassic, cretaceous, tertiary, and alluvial de¬ 
posits. As is shown by the above sketch, this 
is wholly inaccurate; and whatever may be 
thought of my interpretation of the actual phe¬ 
nomena, I trust that, in presenting for the 
first time the formations of the Amazonian 
basin in their natural connection and sequence, 
as consisting of three uniform sets of compar¬ 
atively recent deposits, extending throughout 
the whole valley, the investigations here re¬ 
corded have contributed something to the re¬ 
sults of modern geology. 
THE END. 
