60 



Mr. H. Woodward on the Tertiary Shells 



1866), to give to tlie geological world _j . . ^ 



a new readino: of this creat and won- . ^>>-' &; s a 

 • *^ — — — 



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 summary .^ 

 of them, in order to point out in what &, j 

 degree the wi'iter differs from them. o ''■}> 



In Prof. Hartt's recently published « 1 

 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 

 pei'iod, Avhich has left traces of depo- 

 sits in the province of Ceara and on 

 the Upper Punis. Here and there, 

 whether by denudations or by anterior 

 dislocations, one sees more ancient 

 rocks. Thus Major Coutinho has 

 found palasozoic Brachiopods in a rock 

 which forms the first cascade of the 

 Tapajos ; Carboniferous fossils have v^ 

 been collected on the banks of the g 

 rivers Guapore and Mamore, in Matto ^ 

 Grosso ; and, finally, at Manaos, Cou- § 

 tinho has recognized slates or i^hyl- ^ 

 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 drift." 



Annexed is a copy of the ideal 

 section of these later deposits by Prof, pq 

 Agassiz : — 



02 



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

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

 Triibner. 



t Bulletin de la Society G^ologique de France, 2*= sMe, t. xxv. p. 685. 



