776 CRETACEOUS PALEONTOLOGY. 



clay-marl, near Swedesboro (177) ; Wenonah sand,- near Craw- 

 fords Corner (126*). 



Geographic distribution. — New Jersey. 



Volutoderma ovata Whitfield. 



Plate XCI., Figs. 20-21. 



1892. Volutoderma ovata Whitf., Pal. N. J., vol. 2 (Monog. 

 U. S. G. S., vol. 18), p. 91, pi. 10, figs. 3-4. 



Description. — -"Shell below a medium size, subovate in gen- 

 eral outline, being large above the middle of the length and 

 attenuated toward the base; spire short; its apical angle nearly 

 90° on the internal casts, with strong, rounded volutions and 

 very deep, strongly marked sutures; body volution proportion- 

 ally large, forming nearly the bulk of the cast; greatest diam- 

 eter a little below the shoulder and rapidly diminishing below; 

 aperture large, nearly straight on the inner margin, strongly 

 rounded above on the outer margin, and gently curved along the 

 lower two-thirds of the length; columella proportionally strong, 

 leaving a large cavity on removal, as seen in the cast ; marked by 

 two strong, very oblique plications or folds above the middle 

 of its length, the upper one of which is much the smaller ; volu- 

 tions marked by distant vertical folds only faintly seen on the 

 cast, and only on the upper portions when visible; on the inner 

 surface of the cast, between the volutions, the vertical plications 

 are strongly marked, as in all the species of the genus yet 

 observed; but I have not seen any remains of spiral lines as 

 on most of them, still, I presume they have existed." (Whit- 

 field). , I; 



Remarks. — This species differs from V. bipUcata in having 

 the greatest diameter of the outer volution higher up, so that 

 the shell contracts less rapidly below. The shell closely resem- 

 bles Volutomorpha gabbi Whitf., and it seems scarcely possible 

 that the two should be referred to different genera, as Whit- 

 field has done, although he seems to have considered the two 

 forms to be cogeneric at the time he wrote his description of 



