OF DENISON UNIVERSITY. 
35 
lar, instead of gently curved. Specimens from about loo feet above 
conglomerate II have much larger posterior ears but otherwise remain 
nearly the same. The right valve does not usually have the exception- 
al form referred to by Meek but posseses the usual strong sinus under 
the anterior ear. The surface of the valve is less strongly marked 
than the left which is exquisitely ornamented with alternate radiating 
and keeled concentric striae. As we have already proposed the term 
gramillensis for the form first above described, we may suggest rush- 
villensis for the second, since it is there abundant at the top of the ex- 
posure. These may be regarded as named varieties or formae. 
r 
GRAMMYSIA OVATA, Sp. n. 
(Plate III, Fig. 12) 
Shell of medium size, quite ventricose, convexity being consider- 
ably greater than the heig'it, and greatest tumidity near the umbo 
length to height as 80-45; general outline sharply ovate, acute poster- 
iorly ; anterior margin short, with a deeply impressed lunule ; hinge 
margin gently curved, escutcheon well defined ; lower margin a long 
sweeping curve passing by a sudden fiexture into the dorsal margin 
produced ; beaks incurved almost over the anterior margin ; surface 
striate, Length, 40 mm., height, 23 mm., ventricosity, 26 mm. 
Upper part of division III, Newark, etc 
GRAMMYSIA FAMELICA, Sp. n, 
(Plate VI, Fig. 5.) 
Shell apparently never attaining medium size for the genus, sub- 
oval in outline, moderately convex; height to length as ii to 15; 
greatest convexity near the upper third ; beaks very prominent, in- 
curved, situated rather more than one-third the length from the front 
margin ; lower (basal) margin a very shallow curve, meeting the ob- 
liquely truncated posterior margin rather acutely and curving more 
rapidly to the intersection with the anterior margin at about one-half 
the height of the shell ; anterior margin nearly straight or somewhat 
concave; the escutcheon not distinct, lunule distinct, though short; 
beak enrolled over the hinge-line which is less than one-half the entire 
length; post-umbonal slope scarcely defined. Surface marked by 
