1878.] 31 IRathbun. 



about one fourth the length of the lunge. A shallow, rounded me- 

 dian depression extends from the beak to the front margin. It is bor- 

 dered on each side by a rounded fold of about its own width, which, 

 however, descends much more rapidly on the outer side than on the 

 inner, to another much less defined depression, reaching quite to the 

 cardinal margin. From these lateral depressions outward the valve 

 is slightly convex, or forms a low, very broad fold which extends to, 

 and includes, the cardinal extremities. The margins of the shell 

 are made very sinuous by these foldings of the surface. Length 

 and breadth of the ventral valve each about 5.5 mm. Dorsal valve 

 unknown. 



This very small species of Spirifera resembles much S. rU.iparilis 

 Hall, of the Corniferous limestone of New York. It is readily dis- 

 tinguished from the North American form, however, by its smaller 

 size, greater proportionate length, flatter hinge-area and different 

 character of plications, etc. 



Only a few specimens were obtained; these were all found in the 

 sandstone of the Rio Maecurii. ( Geol. Comm., 1876.) 

 Ambocoelia (V) sp. indet. 



There were encountered in the fossiliferous sandstone beds of the 

 Rio Curua several very small spiriferoid shells, resembling much in 

 shape Ambocoelia umbonata Hall, of the Hamilton Group of New 

 York State. The specimens were all, however, in too imperfect 

 condition to permit of proper identification. 

 Cyrtina ( ?) Curupira Rathbun. 



Bull. Buff". Soc. Nat. Sci., i, no. 4, p. 242, pL x, 1874. 



Quite rare in the sandstone at Erere. (Morgan Exs., 1870 and '71.) 

 Retzia Jamesiana Hartt, MS. 



Rathbun, Bull. Buff". Soc. Nat. Sci., i, no. 4, p. 243, pi. x, 1874. 



A number of specimens of Retzia, identical with the R. Jamesiana 

 of Erere, were obtained from the Devonian sandstone of the Rio 

 Maecurii. From the same locality there are also other specimens, 

 differing from the above in having more prominent and subangular 

 plications, and a second variety has a much broader shell. It is 

 doubtful whether these two latter forms should be included in R. 

 Jamesiana or be separated from that species. 



Devonian sandstone, Erere. (Morgan Exs., 1870 and '71; Geol. 

 Coram., 1876.) Rio Mascuru. (Geol. Comm., 1876.) 

 Retzia Wardiana Hartt, MS. 



Rathbun, Bull. Buff. Soc. Nat. Sci., i, no. 4, p. 245, pi. x, 1874. 



