474 PALEONTOLOGY OF NEW-YORK. 



Platjceras subiiodosum ( n. s.). 



Plate CXV. Fig. 7. 

 Shell spiral, consisting of about a single volution which is nearly in the 



same plane : volution rapidly expanding from the apex, and somewhat 



quadrangular, being flattened on the sides and back, with an obscure 



row of subdued nodes along each angle. 



The specimen is a cast, preserving in one part an impi-ession of the shell, which 

 is transversely striate, with the strise undulating or tortuous at the nodes. 



This species is quite distinct from tlie preceding, in form of volution, arrangement 

 of nodes, etc. 



Fig. 7. View of the upper side of the spire. 



Geological position and locality. In the Oriskany sandstone : Schoharie county. 



Platyccras i^ebliai'di. 



Plate CXVII. Fiq. 1 - 10. 

 Platyceras gebhardi : Conbad. See page 312 of this volume. 



The specimens figured on Plate cxvii were obtained several years after the figures 

 on Plate Lvi had been engraved, and serve to establish more fully the character of 

 the species, as well as to prove its existence in the Oriskany sandstone. 



The specimens of this series are very interesting; showing some forms where the 

 peristome is free, and others where it is spread over the convexity and adhering to 

 the preceding volution, even so far as to be recurved; forming in fact a columellar 

 lip, and leaving a distinct umbilicus as shown in figures 1, 2, 4 & 5. In a single 

 specimen of large size, not figured, the peristome adheres to the volution, and the 

 convexity of the latter is shown projecting within the otherwise symmetrical aper- 

 ture. In another specimen of medium size, the peristome is so closely incorporated 

 with the adjacent volution as to leave only a callosity on the lower half; while 

 below the volution the peristome is a little recurved, and the shell deeply umbili- 

 cate. In this specimen, the continuity of the peristome would hardly be suspected 

 or observed. 



Fig. 1 a, b. A young shell, in which the peristome is closely adhering to the body whorl. 



Fig. 2. A similar specimen with the preceding. 



Fig. 8 a, 6. A larger individual of the same character.* 



