fl^« PALAEONTOLOGY OF NEW-YORK. 



Spirt/era dupUcata. 



Dtltkfrii duplicate i Cokrad, Jonr. Acad. Nat. Science! Philaddphia, Vol. viii, pa. 201, pi. 14, f. 16. 

 M •• : Id. lb., referred to under S. granuli/era, page 223 of this volume. 



Since the precediug pages were sent to the press, 1 have observed, among soma 

 Bpccimcns from the coarser shales of the Hamilton group, the cast of a Spirifer 

 with duplicate mesial fold and angulated ribs, corresponding to the original de- 

 scription of S. dupUcata. The material at hand is not sufficient to determine \\a 

 specific value. 



Sptrifera corticosa. 



Spirifer eorticoia ; Hali,, Tenth Report on the State Cabinet, p. 160. 1857. 



Of this species, I have not obtained sufficient matei'ial to satisfy me of its claim 

 to specific distinction. A well-mai'ked ventral valve, which I have referred to this 

 species, still remains unidentified with any other species ; while two other M'ell- 

 marked individuals*, originally referred to the same, prove to be quite distinct 

 from this and every other species; so that in the present state of knowledge, I 

 propose to leave the specimens without illustration, and subject to future revision. 



Sptrifera tenias. 



Spirifer tenuit : Hju.l, Tenth Report on the Stale Cabinet, p. 162. 1867. 



The specimens on which this species was originally founded are silicified in wholo 

 or in part, and it is impossible to know satisfactorily what cfiect the silicification 

 and partial solution of the shell may have had in removing or modifying suifaoa 

 characters. This species is therefore left undetermined for the present. 



Spirifera pertenuts. 



Spirifer pertenuis .- Hall, Tenth Report on the State Cabinet, p. 163. 1867. 

 The specimens of this species are in a condition similar to the last, and ar« 

 consequently left for farther study. 



• These are probably not from the Ilamilton group, though given to mo as authentic. 



