1913-] REGION ABOUT NATAL, BRAZIL. 449 



This material looks very much like that collected at Ponta de 

 Pedras, which is supposed to be Eocene.^ 



The only fossil which is common to both these localities is 

 Cardium soaresanum Rathbun. 



The general character of the beds shows them to have been de- 

 posited in an estuary. This indicates that such a condition existed 

 then as now along the coast of Brazil, i. e., a sunken coast. 



Cardium (Criocardium) soaresanum Rathbun. 



(Plate XX., Figs. 2 and 2a.) 

 Cardium soaresanum Rathbun. Proc. Bost. Soc. Nat. Hist., Vol. 



XVII., Rathbun, " Cretaceous Lamellibranchs of Pernambuco, 



Brazil," pp. 253-255, 1874. 

 Cardium {Criocardium) soaresanum Rathbun. Extract from Archi- 



vos do Museu Nacional do Rio de Janeiro, Vol. VII., C. A. 



White, " Cretaceous Paleontology of Brazil," p. 90, PI. VI., Fig. 



6, 7, 8, Wash. 1888. 

 Cardium {Criocardium) soaresanum Rathbun. Bull. Geol. Soc. Am., 



Vol. 13, p. 47, J. C. Branner, " Geology of the Northeast Coast 



of Brazil," 1902. 



This is the only species that may be identified in all the material 

 collected from the limestones of the region about Natal, Rio Grande 

 do Norte. Numerous casts were found in every fossil locality and 

 are easily recognized by the fine radial ribs, about 22 in number, 



be distinctly Cretaceous unless the fragmentary impresses of a broadly 

 turreted form showing some peculiar internal lirations should prove with 

 other material to be a true Nerinsea. The fauna bears some resemblance in 

 its little Chione forms to the Maria Farinha fauna, and though evidently 

 representing a phase I am unacquainted with, I should be inclined to regard 

 it as old Eocene. Still, as I said before there is not a single characteristic 

 form wherewith to prove this statement." 



The Journal of the Academy of Natural Sciences of Philadelphia, Vol. 

 XV., lately published, has a paper on some fossils found at Trinidad in the 

 northern part of South America. It settles the age of the Maria Farinha, 

 Olinda and Ponte de Pedras beds definitely as Midway Eocene (pp. 32-33). 

 The beds at Itapasaroca look precisely like those of the Midway Eocene beds, 

 and each contains Cardium soaresanum Rathbun. 



3 J. C. Branner, "Geology of the Northeast Coast of Brazil," Bull. Geol. 

 Soc. Am., Vol. 13, p. 47, 1902. 



