4C4 '' ' L&Ob TOLOQY OF \ All YORK. 



The septa are thin, somewhat thickened and imbricating at the margins. 

 Suture-lines distinct, hut not deeply impressed. The siphunele is unknown. 



The lest and surface-marking are unknown. 



The internal cast preserves the septal markings ; but it is so much 

 \wathered that no indications of surface-markings are preserved. The 

 fragment, measured from the umbilicus to the periphery, at the last septum, 

 has a diameter of forty-five mm. The septa at the base of the lobes are 

 distant from each other nine mm. 



The absence of an open umbilicus leaves the comparison of this species, in 

 its external form and features, with G. uniangularis and G. discoideus. In the 

 direction of the septa it differs conspicuously from these, and in this feature it 

 differs from any form here described. 



Formation and locality. In the Portage or lower part of the Chemung group, 

 at Ithaca, N. Y. 



GONIATITES PATERSONI. 

 PLATKS LXXII, FIGS. 1-5; I. XXIV, FIG. 15. 



Goniatitfs Patergoni, Hall. Thirteenth Rep. N. Y.'state Cab. Nat. Hist., p. 99, figs. 9, 10. 1860. 

 Twenty-Seventh 11.-).. N. V. State Cab. Nat. Hist,, p.. 136. 1876. 

 " " Illustrations Of Devonian Fossils : Cephalopoda, pi. 72, figs. 1-5. 1876. 



Shell large, discoid ; the thickness of the disc equal to a little more than one- 

 third the lateral diameter of the shell in young and medium-sized specimens. 

 Volutions about four, the outer ones embracing the inner to the depth of one- 

 half or more of their dorso-ventral diameter. Umbilicus of moderate width, 

 exposing all the inner volutions. Transverse section somewhat semi-ellip 

 tical, with the lateral faces convex near the base, slightly concave beyond 

 the middle of the width, and abruptly rounded at the apex or periphery 

 The base is deeply indented by the preceding volution, and subauriculate at 

 the baso-lateral angles. The enlargement of the volutions is very gradual in 

 the young state, and more rapidly increasing as the shell advances in age. 

 From the third to the fourth volution the increase is from a diameter of 

 fifteen mm. to thirty-one mm. in a single turn. 



