Maryland Gteological Survey 277 



radiating striae; convex valves; >^li£;litly sinuate basal margin; and 

 distinct cincture on right, which is not niaiked on the left valve. 



Length, 11 mm.; height, 6 mm. 



Occurrence. — Eomxky Formatiox, Ha5[ilton Member. East bank 

 Evitts Creek lielow Wolfe :\lill; B. & 0. R. R. cut at 21st Bridge. 



Collections. — Maryland CTCological Survey; ]^e\v York State ^luseum; 

 American ]\Iuseum of Natural History. 



Superfamily LUCINACEA 

 Family LUCINIDAE 



Genus PARACYCLAS Hall 



Paracyclas lirata Conrad 



Plate XXXIY, Figs. 11-14 



Posidonia lirata Conrad, 183S, Geol. Siirv. N. Y., An. Rep., p. 16, pi. [un- 

 numbered], fig. 12. 



Lucina (Paracyclas) lirata Hall and Whitfield, 1872, Twenty-fourth An. Rep. 

 N. Y. State Mus. Nat. Hist., p. 200. 



Paracyclas lirata Hall, 1885, Pal. N. Y., vol. v, pt. i, I^amellibranchiata ii, p. 

 441, pi. Ixxii, figs. 2-19; pi. xcv, fig. 19. 



Paracyclas lirata Clarke, 1903. N. Y. State Mus., Bull. 65, p. 483. 



Paracyclas lirata Grabau and Shimer. 1909, N. Am. Index Fossils, vol. i, n. 

 555, fig. 760b. 



Description. — "Shell of medium size, subcircular or l)roadly elliptical; 

 length a little greater than the height; margins regularly rounded; car- 

 dinal line short, less than half the length of the shell. Valves moderately 

 convex Iselow, becoming gibboits on the middle and above; beaks anterior 

 to the center, small, appressed, rising liut little above the hinge-line; 

 post-cardinal slope not defined. Surface marked by fine concentric striae, 

 and by strong subangiilar concentric ridges, which are more or less 

 sharply defined, depending upon the condition of the specimen and the 

 nature of the matrix in which the fossil is imbedded." Hall, 1885. 



Several specimens of medium size of this species were collected and one 

 of the large forms. These do not show any particular variation from the 

 forms figured from Xew Yorlc and are clearly tlint species. Their most 



