LAMELLIBEANCHIATA OF THE LOWER MARLS. 165 



and very depressed convex. Beak small, appressed, and situated considerably 

 nearer to the posterior end. Anterior end rounded, gradually sloping from 

 the beak to near the point of greatest length; basal margin broadly curved, 

 and the posterior end truncate below, and obliquely sloping, with a slight 

 convex curvature, from tlie beaks to the postero-cardinal angle. Postero- 

 umbonal slope flattened, and mai'ked by a very faint angulation of the 

 surface. Surface of the shell marked by fine but regular, increasing, flat- 

 tened, concentric ridges, which are separated by narrow impressed lines, and 

 are abruptly bent upward in crossing the umbonal ridge. 



The shells are all broken at the apex and along the postero-cardinal 

 mai'gin, so that the hinge features are not perfectly seen. I have drawn a 

 figure of them of about twice the natural size, as well as I can make them 

 out. The characters are so very obscure that I shall not undertake to 

 discuss their relations from what I can see of them. Dr. Stoliczka in speaking 

 of it considers it as very closely related to the genus Angulus, another 

 division of the TeUinidce, but the specimens which I have seen do not afford 

 material for comparison. 



Formation and locality. — Mr. Conrad's types were from Alabama. The 

 specimens used in the above description are marked Haddonfield, New Jer- 

 sey, and are borrowed from the collection of the Academy of Natural Sci- 

 ences, Philadelphia. They are much smaller than that figured by Mr. Con- 

 rad. There are some internal casts from the micaceous clays beneath the 

 Lower Marls at the Rev. Gr. C. Schanck's pits near Marlborough, New Jersey, 

 which I have referred to the same species, as they have the same form and 

 a few of the surface markings, but they show none of the internal features. 



Genus LINEARIA Courad, 1871. 



(Am. Jour. Conch., Vol. VI, p. 73.) 



Linearia metastriata. 



Plate XXIII, Figs. 6 and 7. 



Linearia metastriata Conrad. J. A. K. Sci., new ser., Vol. IV, ji. 279, PI. XLVI, 

 Fig. 7. Gabb, Synopsis, p. 137. Meek, Cheek-list, p. 14. Also as generic 

 illustration, Am. Jour. Conch., Vol. VI, jjp. 73 and 74, PI. Ill, Fig. 11. 



Shell small, the largest individual seen (a cast) measures a little more 

 than an inch in its transverse diameter. Form of the shell broadly and 



