1887.] NATURAL SCIENCES OF PHILADELPHIA. 19 



marginal umbo, exhibits most delicate concentric lines of growth 

 with ruffled edges, in addition to which also faint radial striae 

 emanating from the umbo are observable. 



Other similarly rounded specimens of Oholella show fine con- 

 centric striation, but in comj^arison with the former may be 

 considered smooth. Also more oval-shaj)ed specimens of Oholella 

 occur. 



The genns Orthis, in a form similar to Orthis pepinensis is 

 likewise represented; another form resembles Kutorgina sculjytilis 

 Meek. Small shells of the shape of Leptmna are also found, 

 and one specimen similar to Metojitoma. 



Some slender stems, consisting of shining carbonaceous matter, 

 seem to belong to Grapholites. Finally I have to mention yet 

 the occurrence of a form of Theca or Hyolites, of the same 

 appearance as Theca primordialis figured by Hall. As I intend 

 to examine this locality myself, as soon as the season allows, I 

 expect to be able to give before long a more complete exhibition 

 of the fauna inclosed within these slate-rocks. 



