Maryland Geological Survey 229 



Ndcula lirata (Conrad) 

 Plate XXV, Figs. 6-8 and 9, 10 ( ?) 



Nuculites lirata Conrad, 1842, Jour. Acad. Nat. Scl. Phila., vol. viil, p. 250, 



pi. XV, flff. 7. 

 Nucula lirata Hall, 1S70, Prelim. Notice Lamellibranchiata 2, p. 3. 

 Nucula lirata Hall, 1885, Pal. N. Y., vol. v, pt. i, Lamellibranchiata ii, p. 316, 



pi. xlv, figs. 5, 11, 15, 17-22, 24, 25; pi. xciii, fig. 5. 

 Nucula lirata Clarke, 1903, N. Y. State Mus., Bull. 65, p. 462. 

 Nucula lirata Grabau and Shimer, 1909, N. Am. Index Fossils, vol. i, p. 395, 



fig. 503d. 



Description. — "Shell of medium size, ovate-triangular; length from 

 one-third to one- fourth greater than the height; basal margin regularly 

 curving, more abruptly rounded at the posterior extremity; cardinal 

 margin slightly arcuate, gradually sloping toward the posterior; anterior 

 end short, subtruncate, usually abruptly rounded. Valves very gibbous, 

 ventricose in the umbonal region ; beaks, at the anterior third or fourth 

 of the length of the shell, distant, elevated, rising considerably above 

 the hinge-line; umbo very prominent. Test thick, marked by regular, 

 strong, subangular concentric undulations, which are crossed by extremely 

 fine radiating striae." Hall, 1885. 



This species is represented by but few specimens in Maryland ; but one 

 from the bank of Evitts Creek below Wolfe Mill, has the shape of this 

 species; its heavy concentric imdulations, part of which show fine con- 

 centric striae on their surface; wliile the best preserved portions of the 

 shell show the very fine radiating striae. There are internal impressions 

 from western Mar3dand and Pattersons Creek, West Virginia, which 

 apparently belong to this species. The complete impression is much 

 thicker than that of N. hellistriata, and the muscular impressions al- 

 though larger are smooth and scarcely so prominent. It is difficult to 

 determine whether these internal impressions belong to iV". lirata or N. 

 randalli and one was sent to Dr. Grabau who wrote " I should prefer N. 

 lirata but it is very difficult to decide. The form agrees better with that 

 species." It is to be remembered, however, that Hall figured a much 

 larger and more gibbous specimen than any of these, which is given as N. 



