MOLLUSCA. 807 



obscurely marked on the cast by a few rather broad spiral lines, 

 which externally, as indicated by impressions, are narrow im- 

 pressed lines. 



Remarks. — The type specimens of A. cretacea, A. ovoidea and 

 A. forbesiana, are all from the Navesink marl, and a careful con- 

 sideration of all these specimens, as well as numerous others, 

 has led to the conclusion that they all represent a single species, 

 for which the prior name A. cretacea must be adopted. Whit- 

 field's type of A. subovoides is also the type of Gabb's A. ovoidea. 

 The several specimens which have been studied are somewhat 

 variable as regards the proportional height of the spire, the 

 diameter of the shell and in the strength of the columellar fold, 

 but none of these variations appear to^ be constant- enough or 

 strongly marked enough toi be considered as oi specific value. 

 The species sometimes attains a large size, as indicated by the 

 dimensions oi the large individual given above, but the more 

 usual size oi the species is that of the smaller individual whose 

 dimensions are given. Besides occurring in the Navesink marl, 

 the species has been recognized in the recent collections of the 

 Survey, only in the Wenonah sand. 



Pormation and locality:. — ^Wenonah sand, near Crawfords Cor- 

 ner (126^); Navesink marl, Atlantic Highlands (108), Cross- 

 wicks Creek (149). 



Geographic distribution. — New Jersey. 



Actaeon gabbana Whitfield. 

 Plate XCIX., Figs. 7-8. 



i860, Actceonina biplicafa Gabb, Proc. Acad. Nat. Sci. Phil. 



(i860), p. 93, pi. 2, fig. 13. (Not Actaeon biplicata 



D'Orbigny.) 

 1861. Actaeonina biblicata Gabb, Synop. Moll. Gret. Form., p. 



94 (38)- 

 1864. Solidula biplicata Meek, Check List Inv. Foss. N. A., 



Cret. and Jur., p. 17. 

 1868. Solidula biplicata Con., Cook's Geol. N. J., p. 728. 

 1876. ActcEon biplicata Meek, Rep. Inv. Cret. and Tert. Foss. 



Up. Mo., pp. 281 and 282. 



