620 CRETACEOUS PALEONTOLOGY. 



area; all the ribbed portion of the shell is also marked by strong, 

 regular, concentric costse, somewhat stronger in the depressions 

 between the ribs than upon the ribs themselves. 



Remarks. — But two specimens of this beautiful little species 

 have been observed, casts of the interior of the shell and impres- 

 sions of the exterior. It is possible that other specimens may- 

 have attained a larger size. The species may be recognized 

 by its beautifully cancellated anterior and posterior regions sep- 

 arated by the smooth median area. These markings are pro- 

 portionally much stronger than in L. metastriata, with the con- 

 trast between the extremities and the median portion of the 

 shell much greater ; besides its smaller size the species also differs 

 from L. metastriata in the greater slope of the cardinal margins, 

 and the lower position oif the greatest anterior and posterior ex- 

 tremities of the shell. The hinge characters of the shell have not 

 been observed, the generic identification being based solely upon 

 its general form and ornamentation. 



Formation and locality. — ^Woodbury clay, Lorillard (102), 

 near Matawan (103). 



Geographic distribution. — New Jersey. 



Linearia contraota Whitfield. 



Plate LXX., Fig. 13. 



1886. Linearia contractaWhiti., Pal. N. J., vol. i (Monog. U. 

 S. G. S., vol. 9), p. 167, pi. 23, fig. 5. 



Description. — "Shell small and moderately convex, transversely 

 ovate in outline, broad in front and abruptly contracted behind 

 the beaks, the anterior end forming about three-fifths of the 

 shell's length. Beaks small and inconspicuous. Anterior end 

 broadly rounded and the posterior more narrowly rounded. 

 Basal line broadly curved. Surface of the shell as seen in a 

 matrix, marked by fine radiating- strise which extend over the 

 entire surface, but are less, strongly developed on the middle of 

 the valve. Also marked by fine concentric grooves parallel to 

 the margin of the shell." (Whitfield.) 



