228 Systematic Paleontology — Middle Devonian 



Nucula bellistriatns Clarke, 1903, N. Y. State Mus., Bull. 65, p. 459. 

 Nucula bellistriata Grabau and Shimer, 1909, N. Am. Index Fossils, vol. 1, 

 p. 395, fig. 503e. 



Description. — " Shell of medmm size, broadly ovate, usually somewhat 

 wider behind; length about one-fourth greater than the height; basal 

 margin regularly curving; posterior end broad and rounded; anterior 

 end short, declining rapidly from the beaks, and abruptly rounded belov? ; 

 cardinal line oblique and arcuate. Valves convex, gibbous on the umbo ; 

 beaks at about the anterior fourth, appressed, rising above the hinge-line, 

 directed forward ; umbonal slope rounded, extending from the beaks in an 

 arching direction, to above the post-basal extremity. Surface marked by 

 fine, regular, sharp, concentric striae, which do not appear to be aggre- 

 gated into fascicles, but are sometimes interrupted, and the surface 

 undulated by strong varices of growth." Hall, 1885. 



The Maryland specimens are mostly somewhat smaller than the figured 

 specimens from New York and again their proportionate length is hardly 

 so great. Still it is thought that they belong to this species which is 

 distinguished by its outline, position of the beak and regular concentric 

 striae, while some of the specimens show varices of growth as represented 

 on figs. 2, 6 and 7 of pi. xlvi of the Palaeontology of New York. The 

 internal impression represented by figures 4 and 5 was identified as this 

 species by Dr. Grabau, and it is essentially smooth with the exception 

 of the conspicuous anterior and posterior muscular impressions which 

 are somewhat wrinkled, the beaks are distant and a thin sharp ridge marks 

 the hinge-line from the anterior to the posterior muscular impression. 



Length, 7-15 mm.; height, 6-12 mm. 



Occurrence. — Romney Formation. Hamilton Member. B. & 0. 

 R. R. cut at 21st Bridge ( ?) . Williams Road, 14 mile east of Queen City 

 Hotel, Cumberland; on National Road, % mile west of Tonoloway Ridge; 

 on Oldtown Road, east of Maryland Ave., Cumberland; east bank of 

 Evitts Creek below Wolfe Mill ; along Flintstone Creek in Gilpin; 1 mile 

 north of Romney, W. Va. 



Collections. — Maryland Geological Survey; New York State Museum; 

 American Museum of Natural History. 



