No. 109.] 125 



Rhynchonella glans-fagea (n. s.). 



Pal. N.Y. Vol. iv. 



Shell broad ovate or subquadrate ; sides sloping from near the 

 middle to the beaks at an angle of about 85°; front rounded : 

 dorsal valve {he shorter, transversely arcuate or sloping from 

 the sides towards the middle, forming a shallow sinus involving 

 nearly the whole width of the shell ; beak not incurved : ven- 

 tral valve much the larger, very prominent and forming an 

 elliptic arch along the middle from beak to front, sloping at an 

 angle of about 80° towards the lateral margins ; beak extended 

 beyond the opposite, arched or incurved so as to bring the apex 

 above the plane of the centre of the other valve. Surface smooth, 

 or with faint concentric lines of growth. 



Geological 'position and locality. Schoharie grit, Albany and Schoharie 

 counties. 



6 5 



4 



3 

 1 



Rhtnchonella olans-fagea. 



Rhynchonella UNISULCATA. 



Pal. N.Y. Vol. iv. 



Atrypa unisulcata, Conrad : Ann. Rep. Geol. Surv. N.Y. 1841, p. 56. 



Shell subquadrangular, broader than long : dorsal valve rising 

 in the middle into an undefined mesial fold, along which a di- 

 stinct longitudinal sulcus extends quite to the apex of the beak ; 

 from this elevation the valve slopes laterally at an angle of about 

 90° quite to the anterior lateral extremities in front, but near 

 the cardinal margin it again curves upwards at the extremities 



