370 A. W. GRABAU — SILURO-DEVONIC CONTACT IN NEW YORK 



Rostral cavity of moderate depth : teeth strong and rounded, sup- 

 ported by two thin hut prominent dental lamella' which diverge hut 

 slightly and arise from the bottom of the valve. Beak apparently trun- 

 cated hy a circular foramen of moderate size. A strong, rather broad, 

 and not distinctly defined median elevation divides the muscular area, 

 which appears to he longitudinally striate. This ridge broadens forward 

 and at the same time hecomes more and more obsolete. The rostral 

 portion of the pedicle valve of this species is Btrongly compressed later- 

 ally, the sides converging uniformly. This gives the shell an elongate 

 appearance, while the actual length is but slightly greater than the 

 width. There is some variation in this, in some cases the length being 

 scarcely more than the width. 



Brachial valve somewhat less convex than pedicle, with the beak in- 

 curved beneath that of the pedicle valve. 



The ovoid form, very slightly diverging dental lamellae, and the median 

 ridge dividing the muscular impression distinguish this species from the 

 preceding one. 



RH YNCHONELL DID 



A single fragment has been found of a coarsely and angularly ribbed 

 brachiopod, with the ribs anterior!}'' incised for the reception of those 

 of the opposite valve. The ribs are too large and too angular to allow 

 reference to Whitfield's Rhynchonella .hydraulicum, from similar rock of 

 Greenfield, Ohio. In this latter species the ribs are rounded on top and 

 they are less coarse. The specimen was obtained at Akron, New York, 

 and is replaced b}' calcite. 



LOXONEMA t Si: 

 (Plate 22, figure ;>.) 



An internal mold showing nothing but the general outline of the 

 volutions and the form of the spire was obtained from the Manlius 

 limestone of Buffalo. Only four volutions remain, separated by rather 

 deep sutures. Whorls uniformly rounded. Angle of divergence between 

 11 and 12 degrees. From the imperfect state of preservation, even the 

 generic determination must be doubtful. 



PLEUROTOMARIA ■ SP. 



A trochiform gastropod, perhaps referable to this genus, was obtained 

 from the Manlius limestone of Buffalo. The specimen is very poorly 

 preserved, only partial molds remaining. The volutions, of which there 

 appear to have been 5 or 6, are rather low and somewhat flattened, with 



