1878.] 15 [Rathbun. 



report should properly follow the detailed account of the Devonian 

 deposits of the Amazonas, which forms a chapter of considerable 

 length in the first unpublished volume of the Geological Commission. 

 The death of Professor Hartt has, however, delayed the publication 

 of that work for a short time, and it has been deemed advisable to 

 issue this report on the fossils at once. It thus becomes necessary to 

 describe here in brief the localities where the species treated of in 

 this paper were obtained, and the character and relations of the 

 rocks in which they were found. 



Prof. Hartt discovered on the Morgan Expedition in 1870 the 

 interesting Devonian locality of Erere, near Monte Alegre, on the 

 Amazonas, where he procured the first Devonian fossils found east 

 of the Andes in South America. In the following year he revisited 

 Erere, and made large additions to his former collections from there. 

 This region he has fully described in the Bulletin of the Buflfalo 

 Society of Natural Science, for January, 1874 (pp. 201 to 235), and 

 in the same publication (pp. 236-261) I have given descriptions of 

 the Devonian Brachiopods obtained by him. In 1876, Mr. Orville A. 

 Derby, of the Brazilian Commission, accompanied by Dr. F. Jose 

 de Freitas and Mr. H. H. Smith of the same Commission, reexam- 

 ined the geology of Erere, and traced the Devonian formation for 

 some distance northward of that region, on the Rios Mascurii and 

 Curud, finding on each of these two rivers richly fossiliferous sand- 

 stones. Passing northward from Erere, the beds are crossed in de- 

 scending order, so that the deposits of Erere are newer in age than 

 those of the Rios Maecuru and Curua. 



The fossiliferous sandstones of the Rio Curud appear to be identical 

 with those on the Mscurii, although the characters of the beds at the 

 two places differ slightly; at the former locality they are fine in 

 texture and hard, while at the latter place they are coarse and 

 friable. At both of these localities, which are distant from one 

 another about twenty-five miles, the fossils are confined to a limited 

 series of beds. From the Mascurii locality to the Erere the distance 

 is about seventy-five miles, the thickness of the intervening deposits, 

 which are largely composed of beds of chert, being in the neigh- 

 borhood of one hundred feet. 



At Erere only three additional species of Brachiopods were found; 

 but on the Msecuru and Curua were discovered thirteen species new 

 to the Brazilian Devonian fauna, of which three species are identical 

 with New York State forms and the remainder, at least in part, new 



