GASTEROPODA OP THE LOWEE GREEN MARLS. 131 



This species is the most elevated form found in the New Jersey marls 

 and is at the same time the most erect. It closely resembles Gyrodes altisjoira 

 of the same author, and in internal casts can be distinguished only by the 

 very slight flattening of the volution adjacent to the suture, and perhaps in 

 a very slightly greater rotundity of the body volution of that species. So 

 far as can be ascertained from the specimens in hand, there has been no 

 thickening of the columellar lip to form a callus or any marking on it what- 

 ever, and the substance of the lip has been rather thin. Mr.-Gabb compares 

 it with N. paludinceformis H. & M., from the Upper Missouri region, which 

 it very closely resembles, and speaks of its open umbilicus. This is not to be 

 considered as meaning a wide open umbilicus, but one not solid as in that 

 species. 



Formation and locality: In the Lower Green Marls at MuUica Hill, near 

 Burlington, near New Egypt, and other places in New Jersey. 



Genus AMAUROPSIS Morch. 



Amauropsis Mbekana, n. sp. 



Plate XVI, Figs. 22-25. 



Amauropsis paludinceformis (in part) Gabb: Synopsis, p. 38; Proc. Acad. Nat. 



Sci., PMla., 1876, p. 396. 

 Not Amauropsis paludinceformis (Hall and Meek) Meek: U. S. Geol. Surv. Terr., 



Invert. Pal., vol. 9, p. 318, PI. xix, Fig. 15. 

 Not Natica paludinceformis Hall and Meek: Mem. Am. Acad. Arts and Sciences, 



Boston, new series, vol. 5, p. 389, PL in, Fig. 3; D' Orb., Prod. Pal., 1850, 



vol. 2, p. 312. 



Shell of medium size, elongate-subovate ; spire moderately elevated, 

 only about two-thirds as high above the aperture as the length of the aper- 

 ture; volutions five or five and a half in the largest specimen; ventricose, 

 with distinct, well marked sutures, which are very slightly channeled; 

 body volution more distinctly ventricose than the others; axis solid; aper- 

 ture ovate, acute at the upper end, rounded and slightly effuse below; 

 out6r lip thin and sharp; columella somewhat thickened by the deposit of 

 the lip, and grooved below the margin of the deposit, but not umbilicate; 

 surface of the shell marked by proportionately strong, transverse lines of 



