414 PALEONTOLOGY OF NEW YORK. 



CONOCARDIUM CONCINNUM. 



PLATE LXVm, FIGS. 26, 27. 



CbMOOordiNm ooncinnttm. Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 68, figs. 26, 27. 



1883. 



Shell small, ovate-cuneate, gradually attenuate anteriorly. Posterior end 

 obliquely truncate along the umbonal angle. Post-cardinal slope slightly 

 concave and projecting at the junction of the valves. Valves marked by 

 numerous radii. Body of the shell, to near the anterior extremity, marked 

 by strong sub-equal radii, as preserved in the cast of the interior. 



This species is not very different in appearance from C. attenicatum, but the 

 ribs are coarser. 



Formation and localities. In the calcareous layers of the Hamilton group, at 

 Pratt's falls, Onondaga county, N. Y. ; and in the arenaceous beds of the same 

 group, from an unknown locality. 



CONOCARDIUM LIRATUM. 



PLATE LXVin, FIGS. 28, 29. 



Qmoeardium liratuin. Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations : PI. 68, figs. 28, 29. 1883. 



Shell small, trigonal ; length less than twice the height. Posterior slope very 

 broad, marked by about five sharp, distant, elevated plications. Anterior 

 part of the body abruptly contracted and marked by about twelve or more 

 finer plications. The entire surface is also marked by fine lamellose concen- 

 tric striae. Interior unknown. 



A specimen has a length of 11 mm. and a height of 6 mm. 



In general form this species resembles C. denticulatum, but is readily distin- 

 guished by the strong plications on the anterior portion. 



Formation and locality. In the Chemung group, Ithaca, N. Y. 



