670 CRETACEOUS PALEONTOLOGY. 



1868. Margarita abyssina Con., Cook's Geol. N. J., p. 728. 

 1892. Margarita abyssina Whitf., Pal. N. J., vol. 2 (Monog. 



U. S. G. S., vol. 18), p. 133, pi. 17, figs. 1-5. 

 1905. Margarita abyssina Johns., Proc. Acad. Nat. Sci. Phil. 



(1905), p. 20. 



Description. — "Shell small, not exceeding half an inch in its 

 greatest diameter; spire moderately elevated, the apical angle 

 being about 70° or 75"; volutions four to four and a half, very 

 ventricose, giving a circular section when broken across; suture 

 deep and well marked, while the whorls in the internal cast are 

 closely appressed and slightly imbedded into^ each other, showing 

 the shell to- be thin; also' seen where 'the cast rests partially in 

 the matrix, the space left by the removal of the shell where no 

 compression has occurred being barely perceptible; umbilicus 

 broad and open, showing several of the volutions within; sur- 

 face marked by very fine, even, spiral lines over the entire shell, 

 with an apparent stronger line on the periphery, and crossed by 

 finer lines of growth which are bent backward in crossing the 

 volution, cancellating the stirface." (Whitfield.) 



The dimensions of a rather large individual are: height, 9 

 mm. ; maximum diameter, 10 mm. 



Remarks. — In the recent collections this species has been ob- 

 served from both the Merchantville and the Navesink formations. 

 The internal casts from the two' horizons seem toi be identical, 

 except that the Navesink individuals attain a somewhat larger 

 average size. The surface markings have been observed only 

 on the Merchantville specimens. It is not possible to determine 

 from Gabb's description from which horizon his type specimens 

 were obtained, the only locality given by him being Burlington 

 County. 



Formation and locality. — Merchantville clay-marl, Lenola 

 (163) ; Woodbury clay, Crosswicks (168) ; Navesink marl, Mid- 

 dletown (113^), near Crawfords Corner (126''), near Freehold 

 (133), near Walnford (148-), Crosswicks Creek (149, 147^, 

 147'', 1Q5), near Jacobstown (150) ; Tinton beds, Tinton Falls 

 (no).' 



