ORDOVICIAN FAUNAS. 173 
GONIOPHORA CARINATUS (Hall). 
Plate XI., Fig. 23. 
1847. Modiolopsis carinatus Hall, Pal. N. Y., vol. I., p. 160, pl. 35, 
figs. 11 a-c. 
Description.—Shell small, subovate in outline, angular posteriorly. 
Anterior margin sharply rounded; basal margin nearly straight or 
slightly convex; postero-basal extremity acutely angular; posterior 
margin obliquely truncate, meeting the hinge-line in an obtusely 
rounded angle; cardinal margin straight, subparallel with the basal 
margin. Beaks small, incurved, elevated above the hinge-line, situ- 
ated at about the anterior fourth of the total length of the shell. 
Umbonal ridge usually describing a slight, sigmoidal curve, sharply 
angular or carinate; the post-umbonal slope concave, sometimes with 
a slight, nearly-obsolete ridge extending from the beak to the middle 
of the truncate posterior margin. Antero-basal slope convex, with a 
slight, ill-defined, shallow sinus extending from the beak obliquely 
backward to near the middle of the basal margin. Surface marked 
by rather strong, more or less irregular, concentric lines of growth. 
The dimensions of the largest specimens observed, a left valve, are: 
length, 14 mm.; height, 7 mm.; convexity, 3.5 mm. 
Remarks.—This little shell is rather uncommon in the Trenton 
fauna of New Jersey, but may be easily distinguished from any of 
its associates by its strongly-carinate umbonal ridge. It was originally 
described as a species of Modiolonsis, but it clearly does not belong 
in that genus, and there seems to be no reason for considering it to be 
generically distinct from Goniophora, which is more characteristically 
a Devonian genus. 
AMPHINURA. 
CHITON ? sp. 
Plate XIIL., Figs. 9-10. 
A single plate, probably the posterior terminal one, has been ob- 
served in the New Jersey collections, which probably belongs to one 
of the Chitons. Its true generic reference is uncertain, but doubtless 
