272 PAL.EONT0LOGY OF NEW-YOEK. 



327. 8. GRAPTOLITHUS SAGITTARIUS. 



Pl. LXXIV. Figs. 1 a, b. 



Prionotus Sagittarius. Hisinger, Leth. Suecica, Supplement, 1S37, pag. 114, pl. 35, fig. fi. 

 Graptolithus Sagittarius. Poktlock, Geol. Rep. Londonderry, IS 13, pag. 3'20, pl. 19, figs. Sab. 



Stipe linear, straight or flexuous, extremely elongated, about one line in width, com- 

 pressed ; one side smooth and the other serrated ; teeth oblique, acute, distant about half 

 the width of the stipe. 



This species is readily distinguished from the preceding, by the regular strong serratures 

 on one side of the axis only. Specimens of eight or nine inches in length are of frequent 

 occurrence, and these are only fragments of much longer ones. It shows no apparent 

 increase or diminution of width in either direction, and neither the lower or upper termina- 

 tion has been observed. There is, apparently, a capillary axis near the smooth margin, and 

 the surrounding substance of the stipe is sometimes of considerable thickness. The character 

 is very uniform, showing, in a large number of specimens examined, no important deviation 

 from those figured. 



This species is distinguished from the G. cUntoni of New-York by its shorter and stronger 

 teeth, and by the same characters from G. murchisoni and G. sedgwickii of Europe. 



Fig. 1 a. A fragment of the slate, showing three nearly parallel stipes of this species. 

 Fig. 1 b. A magnified portion, showing the upper margin of the teeth to be nearly rectangular to the 

 direction of the stipe, while the lower side is oblique. 



Position and locality. This species occurs in the glazed and folded black slates on the 

 Norman's kill, near Albany ; in the town of Stuyvesant, and near Hudson, Columbia 

 county. 



328. 9. GRAPTOLITHUS TENUIS. 



Pl. LXXIV. Figs. 2 a - d. 

 Graptolithus tenuis. Portlock, Geol. Rep. Londonderry, pag. 319, pl. 19, fig. lab. 



Stipe very slender, filiform, straight or flexuous, with one side obscurely and distantly 

 serrated, the other side smooth. 



This species is readily distinguished from the preceding by the appressed, obscure, and 

 more distant serratures. The width in all the specimens examined is less than half that of 

 G. Sagittarius, and it often appears as if both sides were destitute of serratures. 



Fig. 2 a. Slender elongated stipes of tliis species, associated witli G. Sagittarius. 



Fig. 2 b. A portion of one of these magnified. 



Fig. 2 c. A small filiform stipe, gradually tapering and bent abruptly backwards. 



Fig. 2 d. A portion of the same magnified, showing the serratures of the same character as the preceding. 



Positio7i and locality. This species has been seen only in the black glazed slates of the 

 Norman's kill, near Albany. 



