51 



an obscure sinus a little in front of the middle ; hinge slightly ascending 

 backwards, to a point just behind the mid-length. From this point the 

 posterior margin descends, with a straight or gently concave slope, to the 

 posterior angle, which is situated at about one-third the whole height of 

 the shell. Beaks small, closely incurved, almost in contact with each 

 other, at about one-half the height of the shell ; below them the anterior 

 extremity projects two or three lines- From the beak a strong sigmoid 

 angulation extends to the posterior angle. The surface above this is 

 gently concave, and below gently convex. A broad, shallow, barely per- 

 ceptible depression extends from the beak to the ventral margin, which it 

 reaches just behind the middle. Greatest depth of the valve a little in 

 front of the middle. Depth of both valves at this point (in a specimen 

 about two inches long) one inch. 



Locality and Formation. — Indian Cove, Gasp^; Gasp^ limestone, 

 No. 8. 



Collector.— 'K, Bell. 



Grammysia Canadensis. 



Plate 4, fig. 3. 



Description. — Transversely sub-ovate ; posterior extremity obliquely 

 truncated ; dorsal and ventral margins sub-parallel, slightly converging 

 posteriorly ; umbones moderate, rounded, occupying about one-third the 

 height; most projecting point of the anterior extremity situated at about 

 half the height of the shell. The upper posterior angle is obtusely 

 rounded, about one-fifth the length in front of the lower angle, which 

 latter is narrowly rounded or obtusely angular, and just above the line of 

 the ventral margin. The posterior edge, between these two angles, is 

 gently convex, somewhat straight in the middle. Dorsal margin, slightly 

 arched, almost straight, gently curving over the posterior angle, more 

 abruptly rounded at the umbones. • Ventral margin, nearly straight or 

 ^slightly concave in the posterior two-thirds ; the remainder, at first gently, 

 and then somewhat abruptly rounded up to the anterior angle, between 

 which and the umbo there is a concave notch. Length, about twice 

 the height ; the greatest height a little in front of the mid-length. The 

 valves are moderately convex, obliquely flattened from the umbones 

 to the posterior half of the ventral margin. A rounded ridge com- 

 mences at the beaks, and runs obliquely downwards and backwards 

 towards the middle of the ventral margin, before reaching which it be- 

 <;omes obsolete. On each side of this ridge there is a narrow sulcus. A 

 moderately strong rounded angulation extends from the beak, just bilow 



