LAMELLIBRANCHIATA. 415 



CONOCARDIUM RELIQUUM. 



PLATE LXVIII, FIG. 33. 



Cmiocardium reliquum. Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations : PI. 68, fig-. 33. 1883. 



The specimen is the impression of the posterior end, marked by fine radii. 

 The original specimen is not accessible for description. A cast from the origi- 

 nal is recorded as coming from the Chemung group. Locality unknown. 



CONOCARDIUM TEGULUM. 



PLATE LXVIII, FIGS. 30, 31. 



Cunocardium tegulum. Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 68, figs. 30, 31. 1883. 



The original specimen is not accessible for description. The figures illustrate 

 all that is known regarding its characters. The specimen is recorded as from 

 the Niagara group. Locality unknown. 



CONOCARDIUM INCEPTUM. 



PLATE UCVIII, FIG. 32. 



Gmocardiwn ineeptum. Hall. Pal. N. Y., vol. iii, p. 491. 1859. 



" rttgotum, " Pal. N. Y., vol. v, pt. 1. Plates and Exjilanations ; PI. 68, fig. 32. 1883. 



Shell small, sub-ovate. Body of the shell gibbous or ventricose, marked by 

 six or seven strong rounded plications. Posterior extremity truncate, its 

 special characters unknown. Anterior end short, gaping; inner margin 

 marked by a few strong denticulations. Surface of the anterior portion can- 

 cellated by fine radiating and concentric striae, the latter extending over the 

 strong plications and marking the interspaces. 



In the general surface characters it is very similar to C. denticulatum, but 

 the anterior end is comparatively shorter and more abruptly contracted at 

 the extremity ; the ribs on the body of the shell are more rounded. 



The specimen described has a length of 20 mm. 



Formation and locality. In the shaly limestone of the Lower Helderberg 

 group, Albany county, N. Y. 



