436 



A JOURNEY m 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 Cear4 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 

 tbese investigations been published in detail, with the ne- 

 cessary maps, it would have been far easier for me to 

 explain the fects 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 



