226 



NEW YORK STATE MUSEUM 



are subject to variation by compression. In forms where this post- 

 umbonal slope is broader the shell approaches the Orthonota 

 solenoides Sow., 1 of which specimens are before us from the 



Goniophora curvata 



Upper Ludlow of iBradnor lane, Kingston. The latter shell, how- 

 ever, is broader and more produced behind and has a shorter and 

 more oblique hinge line. 



Lower Dez'onic. Balhousie, N. B. 



Sphenotus ellsi nov. 



Shell elongate, subrectangular, hinge line and lower margin 

 parallel. Beak at the anterior fourth of the hinge, anterior slope 



Sphenotus ellsi 



uncurved, anterior margin broadly rounded. Umbones not ele- 

 vated, flattened and divided by a sinus or cincture which traverses 



iMurchison. Siluria. Ed. 3. pi. 23, fig. 9. 



