CONTRIBUTIONS TO PALiEONTOLOtjY. 181 



10 11 12 13 



14 



Fig. 18 & 11. Dorsal and profile views of Camartum typum : 12, interior of the ventral valve^ 

 13, longitudinal section; a, rostral cavity; s, transverse arching septum, or "shoe- 

 lifter" process of King; t, teeth. 



Fig. 14 & 15 illustrate th^ exterior form and characters of Meristella muUicosta of the Ha- 

 milton group, and may be considered as illustrating the general external characters 

 of the genus. 



— ■^♦^ « •*> 



DESCRIPTIONS OF NEW SPECIES OF FOSSILS, 



CaiKFLY FROSI THE HAMILTON GROUP OF WEStfiRX NEW-YORK- 



LINGULA LIGEA(n.s.). 



Shell narrow elliptical; length equal to twice the width; sides regularly curving; 

 extremities subequal; margins of the valves thickened. Surface marked by fine 

 concentric strias, and by a few obscure or obsolete radiating striae. The more 

 convex valve shows, along the inner margin, a narrow shallow groove as if the 

 edge of the opposite valve closed just within its margin. 



The shell is of more equal width throughout and more symmetrically oval, and 

 IS much larger than the £,. spatulata of the Genesee slate. 



Geological formation and locality. In the shales of th€ upper part of the Ha- 

 milton group, on the shore of Seneca lake; and near the base of the Portage group, 

 ^t the falls below Trumansburgh, N.York. 



LINGULA PAL^FORMIS ( n.s.). 

 SSell broadly subovate, convex at the umbo and depressed below, the length a 

 little greater than the greatest width, rapidly expanding for about two-thirds 

 the length of the shell, below which it is abruptly rounded : shell thick. Surface 

 marked by strong concentric lamcUose striae, and, in the exfoliated surface, by 

 fine radiating striae. 



Geological formation and locality. In the shales of the Hamilton group, as- 

 sociated with numerous known fossils, in a loose fragment of rock in the valley 

 south of Cayuga lake. 



