4 io CRETACEOUS PALEONTOLOGY. 



outer margin indicating a strong and abrupt thickening of the 

 valves with a crenulated border; radiating lines indicating mod- 

 erately fine striae show on nearly all parts of the cast, but strongest 

 on the postero-basal section." (Whitfield.) 



The dimensions of Whitfield's type of this species are : length, 

 25.5 mm.; height, 15.5 mm.; thickness, 13.5 mm. 



Remarks. This species is not uncommon at some localities in 

 the Merchantville clay, but it is usually poorly preserved. In 

 fact, three of the species referred to the genus Cibota by Whit- 

 field, but here transferred to Area, A. rostella, A. uniopsis and 

 A. obesa are more or less alike in many respects, and in their 

 condition of preservation in the New Jersey collections it is not 

 possible to determine with certainty whether they may not be 

 different manifestations of a common species. For the present, 

 however, the three species may be considered as distinct, although 

 there may be some doubt, in many cases, as to the correct identi- 

 fication of the imperfect specimens from the New Jersey beds. 



Formation and locality. Merchantville clay-marl, Lenola 



(163). 



Geographic distribution. New Jersey. 



Area quindecemradiata Gabb. 



Plate XXXIV., Figs. 2-3. 



1860. Area quindecemradiata Gabb, Proc. Acad. Nat. Sci. Phil., 

 1860, p. 95, pi. 2, fig. 2. 



1860. Cibota multiradiata Gabb, Proc. Acad. Nat. Sci. Phil., 



1860, p. 95, pi. 2, fig. i. 



1861. Area quindecemradiata Gabb, Synop. Moll. Cret. Form., 



P- 153 (9i). 

 1861. Cibota multiradiata Gabb, Synop. Moll. Cret. Form., p. 



165 (109). 

 1861. Area altirostris Gabb, Proc. Acad. Nat. Sci. Phil., 1861, 



P- 3 2 5- 

 1861. Cueullaa transversa Gabb, Proc. Acad. Nat. Sci. Phil., 



1 86 1, p. 326. 



1864. Area altirostrata Meek, Check List Inv. Foss. N. A., 

 Cret. and Jur., p. 8. 



