60 



Mr. H. Woodward on the Tertiary Shells 



1866), to give to the geological world 

 a new reading of this great and won- 

 derful region. 



It would be impossible, in the length 

 of an article such as the present, to 

 enter fully into Prof. Agassiz's views ; 

 but it is essential to give a summaiy 

 of them, in order to point out in what 

 degree the writer differs from them. 



In Prof. Hartt's recently published 

 work* on Brazil, a resume is given of 

 a paper by Prof. Agassiz and Dr. Cou- 

 tinhof from which we extract the fol- 

 lowing description and section : — 



" Prof. Agassiz thinks that the 

 whole valley of the Amazons was 

 formed at the end of the Cretaceous 

 period, which has left traces of depo- 

 sits in the province of Ceara and on 

 the Upper Punis. Here and thei-e, 

 whether by denudations or by anterior 

 dislocations, one sees more ancient 

 rocks. Thus Major Coutinho has 

 found palaeozoic Brachiopods in a rock 

 which forms the first cascade of the 

 Tapajos ; Carboniferous fossils have 

 been collected on the banks of the 

 rivers Guapor^ and Mamorc, in Matto 

 Grosso ; and, finally, at Mandos, Cou- 

 tinho has recognized slates or phyl- 

 lades in a very inclined position, and 

 beneath the formations of red sand- 

 stone of the Amazonian valley. 



" Prof. Agassiz supposed that during 

 the Tertiary period the Amazonian 

 region was above water, and that the 

 sandstones and clays that now fill it 

 are di-ift." 



Annexed is a copy of the ideal 

 section of these later deposits by Prof. 

 Agassiz : — 



■t>»> M S H M 



pq 



* Scientific Results of a Journey in Brazil, by Louis Agassiz. Geology 

 and Physical Geography of Brazil. By Ch. Fred. Hartt. London, 1870. 

 Triibner. 



t Bulletin de la Soci^t*? G^ologique de France, 2" st'rie, t. xxy. p. 685. 



