404 CRETACEOUS PALEONTOLOGY. 



in the opposite direction. Muscular impression large, the pos- 

 terior one bordered by a slightly elevated lamella on the anterior 

 margin. Surface of the shell marked by radiating lines, strongest 

 on the anterior end and faintest on the middle of the valve ; also 

 by concentric lines which cross them and form slight pustules at 

 the junctions." (Whitfield.) 



The dimensions of an internal cast are : length, 6 mm. ; height, 

 3.5 mm. 



Remarks. This is a rare form and has been observed in the 

 recent collections of the Survey only in the Woodbury clay near 

 Matawan. The species has previously been known only from 

 the Woodbury clay near Haddonfield, and because of the small 

 size of the shells Whitfield has suggested that the very few 

 specimens known might be young individuals of some larger 

 species. The occurrence of the species near Matawan, however, 

 with essentially the same dimensions as the original specimens, 

 and the entire absence of any larger individuals anywhere, would 

 seem to indicate that these specimens were adult. 



Formation and locality. Woodbury clay, near Matawan 

 (103), near Haddonfield (183). 



Geographic distribution. New Jersey. 



Genus BREVIARCA Conrad. 



Breviarca saffordi (Gabb). 

 Plate XXX., Figs. 21-24. 



1860. Area saffordi Gabb, Jour. Acad. Nat. Sci. Phil., 2d ser., 



vol. 4, p. 397, pi. 68, fig. 37. 



1861. Area Saffordi Gabb, Synop. Moll. Cret. Form., p. 153 



(97). 

 1864. Area Saffordi Meek, Check List Inv. Foss. N. A., Cret. 



and Jur., p. 9. 



1868. Trigonarca Saffordi Con., Cook's Geol. N. J., p. 725. 

 1872. Breviarca Saffordi Con., Proc. Acad. Nat. Sci. Phil. 



(1872), p. 55, pi. 2, fig. 3. 

 1875. Trigonarca (Breviarca) Saffordi Con., Kerr's Geol. N. 



Car., App. A., p. 3. 



