235 



of the Amazonas litliological characters are not much to be trusted 

 in the identification of formations. 



li. Series of beds not well exposed ; at x are thin bands of coarse, 

 red sandstone and iron-stone. 



i. The lowest rocks seen were a thick bed of fine, very dark gray 

 clay. 



Not a single fossil was fonnd in the Parauaquara beds, so that 

 their geological age is undetermined. My own decided opinion that 

 they are newer than the Cretaceous and probably of Tertiary must 

 be taken for what it is worth, until the question is settled by pa- 

 laeontological evidence. 



The following paper by Mr. Rathbun on the Brachiopoda of the 

 Devonian of Erere is the result of a long and careful study of the 

 collections under my direction. At my request Mr. Rathbun took 

 a suite of the fossils to Cambridge, Mass., and compared them with 

 the collection in the Museum of Comparative Zoology. Prof. 

 Agassiz received him with the greatest kindness, and gave him 

 every facility for the examination of specimens. I have also to ex- 

 press my thanks to Mr. T. Cary, business manager of the Museum, 

 and to my old friend Prof. 0. H. St. John, for aid rendered to Mr. 

 Rathbun. 



Prof. Hall has since kindly examined the collection, and I am 

 much indebted to him for allowing Mi'. Rathbun to compare the 

 Brazilian fossils with New York types in his collection. My 

 thanks are also due to Mr. Whitfield for his courtesy in aiding 

 in these comparisons. 



I have published a very condensed sketch of the geology of the 

 Erere-Parauaquara district in the Transactions of the American 

 Geographical Society, and the sketch-map at the head of this paper 

 first appeared in that volume, but is now republished with several 

 important changes. 



