486 A JOURNEY IN BRAZIL. 
part of the destruction wrought by the sea on the north- 
eastern shore of this continent. I think it will be found, 
when the coast has been fully surveyed, that a strip of 
land not less than a hundred leagues in width, stretching 
from Cape St. Roque to the northern extremity of South 
America, has been eaten away by the ocean. If this be 
so, the Paranahyba and the rivers to the northwest of it, 
in the province of Maranham, were formerly tributaries 
of the Amazons ; and all that we know thus far of their 
geological character goes to prove that this was actually 
the case. Such an extensive oceanic denudation must 
have carried away not only the gigantic glacial moraine 
here assumed to have closed the mouth of the Amazonian 
basin, but the very ground on which it formerly stood. 
Although the terminal moraine has disappeared, there is, 
however, no reason why parts of the lateral moraines 
should not remain. And I expect in my approaching 
visit to Ceara to find traces of the southern lateral mo- 
raine in that neighborhood. 
During the last four or five years I have been engaged in 
a series of investigations, in the United States, upon the 
subject of the denudations connected with the close of the 
glacial period there, and the encroachments of the ocean 
upon the drift deposits along the Atlantic coast. Had 
these investigations been published in detail, with the ne- 
cessary maps, it would have been far easier for me to 
explain the facts I have lately observed in the Amazonian 
Valley, to connect them with facts of a like character on 
the continent of North America, and to show how re- 
markably they correspond with facts accomplished during 
the same period in other parts of the world. While the 
glacial epoch itself has been very extensively studied in 
