328 Systematic Paleontology 



SCIIUCHEKTELLA WOOLWOKTIIANA (Hall) 



Plate LX, Figs. 4-9 



Strophomena woolworthana Hall, 1857, Tenth Ann. Rept. N. Y. State Cab. 



Nat. Hist., p. 48, figs. 1, 2. 

 Strophomena woolworthana Hall, 1859, Nat. Hist. N. Y., Pal., vol. iii, p. 192, 



pi. xvii, figs, la-1/, 2a-2c, 1861. 

 Orthothetes woolworthanus Hall and Clarke, 1892, ibidem, vol. viii, pt. i, p. 



255, pi. ix, figs. 25-31. 



Description.- — " Shell seniielliptical, often extremely elongate. Ventral 

 valve concave towards the front and flat on the lateral margins, depressed 

 convex near the beak: beak small, and scarcely rising above the edge of 

 the valve. Dorsal valve convex, most elevated near the front, and 

 flattened towards the umbo : beak not projecting. Hinge-line straight, 

 equal to the greatest width of the shell. Area linear, conspicuous, partly 

 common to both valves. Foramen broadly triangular, partially or en- 

 tirely closed. 



" Surface finely striated. Striae round, crowded, simple, increasing by 

 interstitial addition, concentrically crossed by closely arranged striae and 

 a few distant lines of growth. 



" Ventral valve marked interiorly by a broad flabellate vascular area, 

 which is partially limited by the dental lamellae : teeth strong, projecting 

 more or less into the interior of the valve ; in old shells, less conspicuous. 

 Dorsal valve with vascular area strongly marked : cardinal process deeply 

 bifid, and each division again trilobate upon the exterior side; lateral 

 lamellas curving as in Orthis." Hall, 1859. 



This variable species occurs in large and snuill specimens, all apparently 

 mature, as in New York. 



Occurrence. — Heldeeberg Formation, Coeymans Mei^iber. Keyser, 

 West Virginia; Dawson, Devil's Backbone, Corriganville, Maryland. 

 New Scotland ]\Iember. Dawson, Miller's Spring near Cumberland, 

 Corriganville, Devil's Backbone, Maryland; Cherry Eun, Cedar Cliff, 

 West Virginia. Becraet Member. Shale zone at 21st Bridge, Mary- 

 land ; Cherry Run, West Virginia; Warren Point, Pennsylvania. 



Collections. — Maryland Geological Survey, U. S. National Museum 



