108 A JOURNEY IN BRAZIL. 



America, of Azoic, Silurian, Devonian, and Carboniferous 

 formations, shored up against each other by the gradual 

 upheaval of the continent ; although, unquestionably, older 

 palaeozoic and secondary beds underlie, here and there, 

 the later formations. Indeed, Major Coutinho has found 

 palaeozoic deposits, with characteristic Brachiopods, in the 

 valley of the Rio Tapajos, at the first cascade, and car- 

 boniferous deposits have been noticed along the Rio 

 Guapore and the Rio Mamore. But the first chapter 

 in the valley's geological history about which we have 

 connected and trustworthy data is that of the cretaceous 

 period. It seems certain, that, at the close of the secondary 

 age, the whole Amazonian basin became lined with a cre- 

 taceous deposit, the margins of which crop out at various 

 localities on its borders. They have been observed along 

 its southern limits, on its western outskirts along the 

 Andes, in Venezuela along the shore-line of mountains, 

 and also in certain localities near its eastern edge. I well 

 remember that one of the first things which awakened 

 my interest in the geology of the Amazonian Valley was 

 the sight of some cretaceous fossil fishes from the province 

 of Ceara. These fossil fishes were collected by Mr. George 

 Gardner, to whom science is indebted for the most ex- 

 tensive information yet obtained respecting the geology 

 of that part of Brazil. In this connection, let me say 

 that I shall speak of the provinces of Ceara, Piauhy, and 

 Maranham as belonging geologically to the valley of the 

 Amazons, though their shore is bathed by the ocean and 

 their rivers empty directly into the Atlantic. But I 

 entertain no doubt that, at an earlier period, the north- 

 eastern coast of Brazil stretched much farther seaward 

 than in our day; so far, indeed, that in those times the 



