262 



posterior end is conical and gaping behind. A crenulated 

 ventral margin; a straight cardinal line; prominent and 

 strongly-incurved beaks; prominent umbonal ridge, orna- 

 mented with an expansion of the test in continuation of 

 the truncated anterior end; external ligament; concentric 

 striae and strong- radii. — are characteristic features of this 



genus. 



CoNOr-ARDIUM XORMALE. 



Hall. 



Fig. 



181.) (Pal. N. Y., 

 Vol. VII.. p. Ill, 

 Pl.LXVm.) 



D is t i n g u ishiiig 

 Characters. — Large 

 size; trigonal out- 

 line; tapering pos- 

 terior end ; short, 

 distant radii, with 

 tine striji:' in the 

 interspaces ; concentric, undulating striiie. 



Found in the Encrinal limestone, at Section 5 (a frag- 

 ment). 



COXOCARDIUM EBORACEUM. Hall, (Fig. 182.) (Pal.N.Y., 

 Vol. VII., p. 412, PI. LXVIII.) 



Distinguishing Chamcters.— SnmW size, sub-ovate outhne; 

 o-entlv curvino- basal margin; slightlv concave truncated 



Fig. 181. Conocardium normale. The left side of a 

 large specimen (from Hall). 



Fig. 182. Conocardium eboraceum. Right and ventral views of a small specimen 

 enlarged, x 2 (from Hall). 



end; abruptly-contracted and nasute tapering end; con- 

 centric lamellose striae, and radiating plications, obscure on 

 the perfect test; radii continued beyond the concentric 

 lamin* at the margin as strong interlocking denticulations. 



