GASTROPODA. 259 



New York Oriskany, but very similar in size to the ones occurring at Cumberland, 

 Maryland. 



Horizon — Lower and upper beds. 



Figured specimens No. 27521, Walker Museum. 



Platyceras peregrinus sp. nov. 

 Plate 69, figures 13, 14 



Description — Only a fragmentary portion of one shell has been observed. Shell 

 depressed, discoidal, whorls probably not more than one; apex of spire incomplete, but 

 apparently obtuse; younger portion of the shell less compressed than later stages, the 

 more pronounced compression beginning rather suddenly about one-third the dis- 

 tance from the apex. Suggestions of parallel transverse undulations are present in the 

 older part of the shell. Character of aperture not observed. 



Remarks — -This form may be distinguished from all the other Platycerids present 

 in the fauna because of the strong lateral compression. Tn general shape the specimen 

 agrees best with Platyceras ccmpressum Clarke and Swartz, from the Chemung of 

 Maryland, but expansion of the whorl is more rapid in that form, and compression begins 

 closer to the apex. Some resemblance to Platyceras whitii Clarke, from the Devonian 

 of Para, is also suggested, but the dorsal ridge of that form is absent here. 



Horizon — Lower beds. 



Holotype No. 27517, Walker Museum. 



Platyceras planovolvis sp. nov. 

 Plate 70, figures 1-5 



Description — Shell medium to large, discoidal, consisting of 3 or 4 gradually but 

 rapidly expanding whorls, which in the majority of the specimens are closely coiled in 

 one plane; whorls contiguous with the exception of one or two specimens and in these 

 the outer volution is free; spire in same plane or very slightly depressed below body 

 volution. In cross section the whorls present a circular to an oval outline. 



Aperture entire, shape varying from sub-circular or transversely oval to longi- 

 tudinally oval, expanded, almost campanulate; outer lip of peristome extended, inner 

 contiguous with body volution. Upper side of body whorl slightly flattened to gently 

 and evenly convex. 



Surface marked by transverse striae, closely packed, and undulating. A few of 

 the specimens show traces of transverse ridges. 



Remarks — This is the most abundant species of the genus in the Little Saline 

 limestone and is distinct from all the associated species by reason of the character of 

 coiling in one plane. It is represented by the internal casts only; rarely these have por- 

 tions of the shell attached which reveal the surface features. The specimens present 

 a distinct variation in size, in outline of aperture, in rapidity of expansion of whorls, 

 and in amount of depression of spire, but all exhibit the same even manner of coiling in 

 one plane, and the expanded aperture. 



Horizon — Lower and upper beds. 



Holotype and Paratype No. 27526, Walker Museum. 



Platyceras reflexum Hall 

 Plate 69, figures 7-9 



1859. Platyceras reflexum Hall, Nat. Hist. N. Y. Pal., vol. 3, p. 477, pi. 120, figs. 1-7, 



1861. 

 1913. Platyceras reflexum Ohern, Geol. Surv., Md. Low. Dev., p. 473, pi. 83, figs. 5, 



6; pi. 84, figs. 1, 2. 



