MOLLUSCA. . 637 



curve to the antetior and ventral margins, and more gently to the 

 postero-basal extremity; each valve with an angular, umbonal 

 ridge, that of the left valve much the more conspicuous; post- 

 umbonal slope of the right valve narrow, slightly concave, in- 

 flected to the hinge-line towards the beak ; that of the left valve 

 much broader, concave, sloping much more abruptly, not in- 

 flected. Surface of the right valve marked by rather regular, 

 moderately fine, rounded, concentric costse, which seem to ter- 

 minate at the umbonal ridge; the left valve marked by more or 

 less irregular concentric lines of growth which are not raised 

 into distinct, rounded ribs, and on the anterior portion of the 

 valve by a few indistinct radiating costse. 



On the internal casts the surface is smooth, the muscular im- 

 pressions are indistinct, and the beaks are widely separated and 

 erect. The general form and contour of the valves is the same. 



Remarks. — The specimens which have been used in the de- 

 scription of this species were collected by Mr. John M. Manley, 

 of New Brunswick, at Furman's clay pits, Sayreville, New Jer- 

 sey. They are of special interest because they were ■ collected 

 from near the base of the Raritan formation, at a horizon which 

 has rarely yielded invertebrate fossils. The species is a very 

 peculiar and distinct one, and is quite different from any other 

 Corhida in the faunas of the New Jersey Cretaceous beds. 



Formation and locality. — Raritan formation, Sayreville. 



Geographic distribution. — New Jersey. 



Corbula lorillardensis n. sp. 



Plate LXXIL, Figs. 9-14. 



Description. — The dimensions of an internal cast are: length, 

 10.5 mm.; height, 5.5 mm; thickness, 4 mm. Shell elongate 

 subovate in outline, broader in front than behind; the beaks 

 central or a little in front of the carter, broadly obtuse, a little 

 incurved ; right valve overlapping the left along the ventral mar- 

 gin. Anterior and posterior cardinal margins sloping downward 

 in front and behind the beak, meeting at an angle O'f about 142° ; 

 anterior margin regularly rounding from the cardinal into the 

 basal margin; basal margin long, gently convex; postero-basal 



