GLACIAL PHENOMENA. • 299 



to a cletermination of the question whether or not there 

 has heen an intermingling of different floras, sucli as is 

 thought would be attendant upon a cosmic winter, we 

 make the assertion that there has been no " intei'tropical 

 cold epoch." The question respecting the origin of the 

 principal deposits of the Amazonian Valley aiFects only a 

 theory, while the one of an intertroi^ical winter brings us 

 in relation to facts. No theory which militates against 

 facts, pronounced as such by our most accurate observers, 

 can j^rove subservient to the cause of truth. The fact of 

 the existence of ancient local glaciers in the tropics will 

 not admit of a hasty denial. Let us note some observa- 

 tions made by explorers of the valley. We make from 

 " A Journey in Brazil " the following quotation, which 

 gives the results of Prof. Agassiz's researches among the 

 serras of Ceara, near the picturesque little village of 

 Pacatuba : " On this very serra of Aratanha, at the foot 

 of which we happen to have taken up our quarters, the gla- 

 cial phenomena are as legible as in any of the valleys of 

 Maine, or in those of the mountain of Cumberland in 

 England. It had evidently a local glacier, formed by the 

 meeting of two arms, which descended from two depres- 

 sions, spreading right and left on the upper part of the 

 serra, and joining below in the main valley. A large 

 part of the medial moraine formed by the meeting of these 

 two arms can still be traced in the central valley. One 

 of the lateral moraines is perfectly preserved, the village 

 road cu.tting through it ; while the village itself is built 

 just within the terminal moraine, which is thrown up in a 

 long ridge in front of it. It is a curious fact that, in the 

 centre of the medial moraine, formed by a little mountain- 

 stream, making its way through the ridge of rocks and 

 bowlders, is a delicious bathing-pool, overgrown by 

 orange-trees and palms." Upon the side of the serra of 

 Erere, on the northern shores of the Amazons, opposite 



