382 



NORTH AMERICAN INDEX FOSSILS. 



Hamilton : New York, Virginia. 

 24. G. lirata Hall. (Fig. 486, d.) 



Devonic. 



Fig. 486. a, b, Grammy sia nodocostata ; c, G. obsoleta ; d, G. lirata; e,f, G. 

 arcuata ; g, G. circularis, left valve, partly denuded of shell, showing muscle scars 

 andpallial line ; A, G. communis ; i, G. undata, a small left valve. (Pal. N. Y., V.) 



