UTICA SLATE AND HUDSON-RIVER GROUP. 273 



329. 10. GRAPTOLITHUS SEXTANS (n.*p.). 



Pl. LXXIV. Figs. 3 a - «. 



Slender, bifurcating from the base ; branches linear, straight, serrated upon the outside ; 

 serratures oblique ; teeth sharp, and extended into a slender mucronate point. In perfect 

 specimens, two small setae extend from the base, one on each side. 



This small species appears to be quite distinct from either of the others. In a considerable 

 number of specimens examined, it bifurcates at the base, from beneath which two slender 

 spines or bristles proceed. The bifurcations are straight, and regularly diverging at an 

 angle of sixty degrees. The angular teeth on the outer margin always preserve a mucronate 

 point when perfect, and this character is sufficient for identifying small fragments. 



Fig. 3 a. A fragment of slate on which are two specimens of this species, with straight diverging 



branches. 

 Fig. 3 4. A portion of one of these magnified, showing the mucronate teeth. 

 Fig. 3 c. Specimen with larger branches. 



Fig. 3 A, d. Two specimens, showmg the appendages at the base. 

 Fig. 3 e. One of the last magnified. 



Position and locality. This species is known to me only in the black slates of the Norman's 

 kill, near Albany. {State Collection.) 



330. 11. GRAPTOLITHUS FURCATUS («.«;>.)• 



Pl. LXXIV. Figs. 4 a-/. 



Stipes slender, bifurcating near the base ; branches diverging, curved in the centre, and 

 converging towards the extremities ; stipe below the bifurcation serrated on both sides, 

 branches serrated on the outside ; teeth nearly as wide as the branches, rectangular, obtuse ; 

 inner side of the branches more obliqely serrated. 



This small and peculiar species is readily distinguished from either of the preceding, by 

 its curving bifurcations, and shape of the serratures. In a large number of specimens 

 examined, it preserves the form and character given in the figures, and a single branch 

 can be distinguished by a careful comparison. It differs in its mode of bifurcating from G. 

 ramosus, and is always smaller and narrower. 



Fig 4 a. An individual on the same stone with 3 d, showing the difference in form. 



Fig. 4 A. A magnified portion of the same. 



Fig. 4 c. A small specimen, with the branches more converging than usual. 



Fig. 4 d. A portion of the last magnified, showing no serratures on the inside of the branches. 



Fig. 4 e. Another specimen, similar in form to 4 c. 



Fig. Af. A part of the same magnified, showing serratures on the inside of the branches. 



Position and locality. In the glazed slates of the Norman's kill, near Albany, 

 ( Pal.«:ontology I 35 



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