70 PALAEONTOLOGY OF NEW JEESEY. 



sandstone, rather unlike any other fossil which I have seen from New Jersey, 

 but is distinctly marked "N. J." in the collection of the Academy of Natural 

 Sciences, Philadelphia, in what I take to be Mr. Conrad's writing; while it 

 is also marked "type." I am inclined to infer from the above facts, and 

 the close resemblance it bears to Dr. Morton's figure, that the specimen is 

 Morton's type, and that it came from Delaware rather than Kew Jersey ; 

 also that the figure in the "synopsis" has been reversed by the lithographer, 

 making a right valve with the characters pertaining to a left valve in this 

 w-ay. The shell is so unlike any other known New Jersey species that 

 there can be no difficulty in recognizing it. I am somewhat inclined to 

 think the species belongs to the group to which Mr. Meek applied the generic 

 name Oxytoma, but in the absence, or rather imperfection of the anterior part 

 of the hinge line, I am not positive. 



Formation and locality. — Probably from Delaware, although distinctly 

 marked on the label "N. J." in the collection of the Academ}^ of Natural 

 Sciences, Philadelphia. The position in the series not determined. 



Pteria navicula, u. s. 

 Plate XIV, Fig. 8. 



Shell of small size, the greatest length being less than half an inch ; 

 very oblicpie and angularly ventricose, the height scarcely more than half 

 the length. Hinge line nearly as long as the body of the shell, mucronate 

 and slightly prolonged ar the posterior extremity, which is separated from 

 the body of the shell by a slight sinuosity. Anterior wing, if any, not 

 preserved on the specimen; but the shell, although somewhat imperfect, 

 does not appear to have been winged on the anterior side. Posterior 

 extremity of the body of the (left) valve obtusely pointed, and the anterior 

 end narrowly rounded from the extremity of the cardinal line. Basal line 

 broadly curved, gi'adually descending from the anterior end to about the 

 posterior third of the length, where it again rises to the extremity. Beaks 

 small, rising a little above the hinge line, and prominently ventricose. 

 Surface of the shell marked only by concentric striae, so far as can be 

 determined from the partially exfoliated individual. Eight valve unknown. 



There is only a single left valve of the species known so far, but the 

 form is so decided that there is no possibility of confounding it with any 



