﻿302 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



9. The evidences of depression consist of: 



(a) The open bays: Rio de Janeiro and Bahia. 



(b) The partly choked-up bays, such as Santos and Victoria. 



(c) The coast lakes formed by the closing of the mouths of estuaries such as Lagoa 

 Manguaba, Lagoa do Norte, Jiquia, Sinimbu, etc. 



(d) Embayments altogether filled up. 



(e) The islands along the coast are nearly all close in shore and have the appearrance 

 of having been formed by depression of the land. 



(/) The buried rock channels at Parahyba, now filled with mangrove swamps and 

 mud, show a depression of at least twelve metres since those channels were cut. 

 (g) Wind-bedded sand below tide level on Fernando de Noronba. 



10. The evidences of elevation consist of: 



(a) Elevated sea beaches especially well shown about the Bay of Bahia, and along 

 the coast of the State of Bahia. 



(6) Marine terraces about Ilheos in the State of Bahia. These are about eight 

 metres above tide level. 



(c) Horizontal lines of disintegration about one metre above high tide in granites 

 and gneisses at and about Victoria, State of Espirito Santo. 



{d) Burrows of sea urchins so far above low tide that sea urchins can not now live 

 in them. These are well shown at Pedras Pretas on the coast of Pernambuco. 



11. Of the two movements the depression has been much the greater and was the 

 earlier. 



12. The great depression probably took place in early Pliocene times. 



Additional evidence in support of the submergence of the Brazilian 

 coast is given by O. P. Jenkins.^ 



That the last dominant shift in the position of the strand line in 

 eastern Brazil was by submergence, it seems to me, is incontrovertible, 

 and that the Brazilian reefs are merely growing on the surface of a 

 submerged continental shelf is too obvious to need defense. In these 

 relations the Brazilian reefs accord with all other American offshore 

 reefs, perhaps with the exception of the Barbadian reef specially 

 mentioned on page 301. Professor Branner dates the submergence 

 whereby the BraziUan harbors were brought into being, as PUocene; 

 whereas the submergence in the other areas discussed is clearly 

 Recent. Without definite evidence I should not be justified in giving 

 the drowning a later date than that assigned to it by Professor Branner; 

 but I now know that I assigned too great antiquity to some physio- 

 graphic features I considered about the same time that he was engaged 

 on his work on the BraziUan stone reefs ; for instance, the higher Cuban 

 terraces are Pleistocene and not Phocene, as I said in the Cuba report 

 previously cited. May not the antiquity of the submergence of the 

 Brazihan coast be less than Professor Branner inferred? May not 

 both the submergence and the minor uplift following it be post- 

 Pleistocene in age ? Should the two events mentioned be geologically 

 Recent, the shore-line history of Brazil would parallel that of eastern 

 Central America. 



1 Jenkins, O. P., Geology of the region about Natal, Rio Grande do Norte, Brazil, Amer. Philos. Soc. 

 Proc, vol. 52, pp. 431-465, 1913. 



