114 PALEONTOLOGY OF NEW JERSEY. 



the shell at right angles with the lunule, exhibiting a tendency to being no- 

 close, especially near the lunule; lunule marked by ten or twelve transverse- 

 ribs; cardinal margin somewhat incurved, anterior end subtriangular, basal 

 sinuous and deeply serrate, posterior regularly rounded ; internally, hinge- 

 teeth small; muscular impressions deep; pallial line entire; a small tooth- 

 like ridge or process extends along the middle of the alation, as in T. alcc- 

 formis.'" 



The above description is in some particulars rather incomprehensible,, 

 from the reversal of the anterior and posterior of the shell, as usually given 

 by other authors. If these are considered it is much more lucid; and in 

 the same way that which is termed the lunule would be the area bordering 

 the cardinal line. The species very closely resembles what young individ- 

 uals of T. tJwracica must have been, but appears to possess more ribs pro- 

 portionately for the size of the specimens. At the typical locality (Eufaula,. 

 Ala.) the specimens are always quite small, and considerably prolonged 

 behind, with the basal margin strongly denticulated b}' the projection of 

 the ribs The small cast figured has a larger number of ribs proportionally 

 than have those from near Red Bank, one of which is also figured, and is 

 more distinctly removed specifically from 1\ tJioraclca Morton. 



Formation and locaUty. — In the micaceous cla5's of the Lower Marl 

 Beds, at the "crossing of the West Jersey Railroad at a creek between Red 

 Bank and Gloucester, N. J.," and in the green marls in Monmouth County. 

 The former are from the collection of the Academy of Natural Sciences of 

 Philadelphia, and the latter from the collection at Rutgers College. 



Trigouia cerulia, n. sp. 

 Plate XIV, Fig. 7. 



Shell small or below a medium size, moderately convex on the valves 

 and of a triangularly-ovate outline. Beak small, appressed, obtusel}- pointed 

 and erect; posterior hinge-line long and slightly concave ; posterior end 

 narrow and rounded ; anterior end broadly rounded ; basal line a little gib- 

 bous in the middle, but otherwise forming a continuous line with the ante- 

 rior and posterior margin.^. Surface of the shell covered by coarse elevated 

 ribs, Avhich are flattened on their surfaces over a large part of the shell, but 



