Maryland Geological Survey 467 



aperture nearly circular. Surface of cast marked by faint transverse 

 ridges and finer longitudinal striiie." Hall, 1859. 



" . . . . characterized : 1 by the sharply concentric lamellae of the sur- 

 face ; 2 by the broadly expanded aperture ; 3 by the well-defined median 

 ridge on the earlier parts of the shell, on which the striae have a pronounced 

 retral bend, the ridge being obsolete at the margin." Clarke, 1900. 



In the collection of Mr. George M. Boeder is to be found the only entire 

 specimen which the writer has seen from Maryland. The agreement with 

 Hall's description is very exact. 



Diameter of shell 6.2 cm. ; of aperture 4.75 cm. 



Occurrence. — Oriskany Formation, Ridgely Membeb. Williams 

 Road near Cumberland. 



Collections. — Maryland Geological Survey, George M. Roeder. 



[Ohern.] 



Order CTENOBRANCHIATA 



Suborder PLATYPODA 



Superfamily GYMNOGLOSSA 



Family PYRAMJDELLIDAE 



Genus LOXONEMA Phillips 

 LoXOXEilA FITCHI Hall 



Plate LXXIX, Fig. 7 



Loxunema fitchi Hall, 1859, Nat. Hist. N. Y., Pal., vol. ill. p. 296, pi. liv, figs. 9, 

 lltt. b, 1861. 



Description. — " Shell subfusiform, very gradually attenuate : volutions 

 seven or eight. Surface unknown." Hall, 1859. 



Volutions broadly arched, wide, suture deeply impressed. A few im- 

 perfect casts which may be from the Helderberg agree well with Hall's 

 description and figures. In the state of their preservation no further 

 features can be observed. 



Occurrence. — Helderberg Formation. Tonoloway. 



Collection. — ^laryland Geological Survey. 



[Ohern.] 



