CONTmBUTIONS TO PALEONTOLOGY. 59 



and a large well-preserved specimen, with expanded aperture, 

 measures seven-eighths of an inch from the back of the dorsum to 

 the front of the aperture, and the aperture has a transverse diameter 

 of one inch and a half. 



This species resembles in form and surface-markings the B. deciissatus 

 of Fleming =-B. elegans and B. clathratiis of D'Orbigny, and B. can' 

 cellatus of Hall. 



This species is well marked, and readily distinguished from any other in 

 the formation, except the following species [B. lyra), which bears some 

 resemblance, but is more evenly expanded and with diiFerent surface mark- 

 ings. The broadly expanded aperture, with nearly smooth borders, is rarely 

 seen in ordinary specimens. In specimens of this character, however, the 

 dorsal band is sometimes much elevated near the front. 



Geological formation and locality. In the Hamilton group : Lake Erie 

 shore at Hamburirh, N.Y. 



BELLEEOPHON LYRxV ( n. s.). 



Shell subglobose; the last half of the body-volution very ventricose 

 and abruptly spreading towards the aperture, which is extremely 

 expanded and round-oval in form, a little wider than long. Peri- 

 stome distinctly sinuate in front. 



Surface marked by regular even revolving strise, which are wider 

 than the spaces between them; or the larger ones appearing to be 

 composed of two or three smaller ones, with a narrow scarcely 

 impressed line between. These striee are slightly undulating and 

 very distinct, to near the aperture, where they terminate in a 

 narrow smooth border, which is not thickened exteriorly. There 

 are no distinct transverse strise, though faint lines of growth are 

 visible under a lens. The dorsum is marked by an elevated carina, 

 which is crossed by distinct elevated arching and subimbricating 

 or lamelliform strise or ridges, at the distance of about two or 

 three in the space of a line. 



This species bears some resemblance to B. leda; but the aperture is more 

 equally and less abruptly expanded, and there are no conspicuous transverse 

 striae, while the revolving striae are broader, and the dorsal band elevated 

 into an obtuse carina with distant imbricating striae. Length of aperture 

 about seven-eighths of an inch, with a transverse diameter of an inch. 



Geological formation and locality. In the coarser shales of the Hamil- 

 ton group at Fultonham, Schoharie county, N.Y. 



1861.] 



