386 PALEONTOLOGY OF NEW YORK. 



can be compared. The specimens, showing the strong oblique folds on the 

 umbonal slope, were separated from the others, and designated as Cardiomorpha 

 undulala, as cited above ; a farther comparison shows that these are only old 

 individuals of the original species. 



Formation and locality. In the Portage group, six miles north-east of Port- 

 land Harbor, in Chautauqua county, N. Y. 



EDMONDIA, De Koninck. 1844. 

 Edmondia rhomboidea. 



PLATE LXIV, FIGS. 7, 8 ; AND PLATE XCV, FIGS. 15, 16. 



BdtHondia rhomboidea (Hall), S. A. MtLLUR. Cat. Am. Pal. Foss., p. 191. 1877. 



Pal. N. Y., vol. V, pt. 1. Plates and Explanations : PI. 64, figs. 7, 8. 1883. 



Shell small, rhomboid, sub-circular ; length a little greater than the height ; 

 pallial margin regularly rounded from the two extremities, with the posterior 

 end sometimes sub-truncate. Cardinal line short and straight. 



Valves regularly convex below, gibbous in the middle and above. 



Beaks at about the anterior third, large and prominent, incurved. Umbo- 

 nal angle obtuse above, merging into the general convexity of the shell. 



The surface of the cast preserves evidences of fine concentric striaB, 

 which are fasciculate on some portions of the shell, and of fine radii which 

 have been principally observed on the anterior half of the shell. 



There is a slight fold, indicating a lateral tooth, on the postero-cardinal 

 margin. Other characters of the interior unknown. 



The two specimens described measure respectively 22 and 23 mm. in 

 length, and 19 and 21 mm. in height. 



This species somewhat resembles E. Philipi, but it is usually a more nearly 

 circular and more gibbous form. 



Formation and localities. In the sandstones of the Chemung group, at Sala- 

 manca, and four miles north of Panama, N. Y. 



