LAMELLIBRANCHIATA. 4G3 



SOLEMYA, Lamarck. 1818. 



( Janeia, King. 1850. ) 



SoLEMYA (Janeia) vetusta. 



PLATE Xl.VlI, FIGS. 53-55; aNU PLATE XCIV, FIG. 10. 



iSolenuia (Jaiieia) vetusta, Mkkk. Proc. Acad. Nat. Sci., Phila., p. 10. 1871. 



Pal. Ohio, vol. 1, p. 206, pi. 18, tig-. 4. 1873. 

 Yoldiaf volvulus. Hall and Whitfield. Twenty-fourtli Ann. Rep. N. Y. State Mus. Nat. Hist., p. 190. 



1872. 

 " " " Hall. Pal. N. Y., vol. v, i)t. 1. Plates and Explanations : 



PI. 47, tigs. 53-.55. 1883. 



Shell of medium size, elongate-elliptical ; length more than twice the height; 

 basal margin very gently curved. Posterior extremity rounded. Cardinal 

 line nearly straight, or gently arcuate. Anterior end large, narrower than 

 the posterior, rather abruptly rounded at the extremity, carrying on its upper 

 margin a distinct fold. 



Valves moderately convex below, scarcely gibbous in the upper portion. 



Beaks inconspicuous, situated anterior to the middle. 



Surface marked by regular, distinct, laiiiellose, undulating, concentric 

 striae, which are crossed by distant radiating lines, between which the con- 

 centric striae curve downward. 



Three specimens measure respectively 26, 27 and 35 in length, and 11, 12 

 and 15 mm. in height. 



A careful examination has shown that this species is closely allied to 

 SoLEMYA, and we have not a sufficient knowledge of the interior structure to 

 separate it from that genus. 



Formations and localities. In the cherty layers above the Hydraulic beds, at 

 the falls of the Ohio, in strata referred to the Hamilton group. It is cited by 

 Mr. Meek as occurring in the Corniferous limestone, at Dublin, 0. 



