550 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
Chatham Hill formation in Virginia: 1.2 miles S. 31° E. of Sharon Springs, 
Burkes Garden (15’) Quadrangle; Grayson Farm, 4 miles southwest of Bland, 
Bland County; on Virginia Highway 113, Marion-Chatham Hill Road, 6 miles 
north of Marion, Chatham Hill (T.V.A. 218-NE) Quadrangle; 150 feet above 
the black beds in Porterfield Quarry, 5 miles east of Saltville, Maccrady (T.V.A. 
218-NW) Quadrangle. 
Sevier shale in Tennessee: 4+ mile along the wagon road northwest of Bulls 
Gap, Bulls Gap (T.V.A. 171-SE) Quadrangle. 
Edinburg formation (Cyrtonotella bed) in Virginia: Along Tumbling Run 
14 miles southwest of Strasburg, Strasburg (15’) Quadrangle; ravine at switch 
s to 4 mile east of Strasburg Junction, Strasburg (15’) Quadrangle; Colliers 
Creek, $ mile north of the junction of Virginia Highways 251 and 612, west- 
southwest of Lexington, Rockbridge County ; Hiatt Run, 200 yards east of U. S. 
Highway 11, 3 miles north of Winchester, Winchester (15’) Quadrangle. 
Discussion.—This species is characterized by its large size and its numerous 
fine costellae. It attains the largest size of any species occurring in the Appa- 
lachian Valley. This species is quite suggestive of O. gouldi Ulrich and Cooper, 
but it does not attain the size of the largest specimens of the Oklahoma species. 
It is also somewhat more convex on the brachial side, has a narrower and more 
elevated fold, and is more umbonate in the brachial valve. The pedicle beak of 
O. gouldi is more incurved than that of O. multicostellata, and the ornamenta- 
tion is somewhat finer. 
Oxoplecia multicostellata is similar to O. nevadensis but differs in its some- 
what finer costellae, its somewhat larger proportions and more rounded outline. 
It has a more inflated umbonal region than the Nevada form and a less erect 
pedicle beak. Ovoplecia simulatrix is another large species with which O. multi- 
costellata might be confused, but it has different proportions, being a wider shell, 
and also is more strongly costellate. 
OXOPLECIA NEVADENSIS Cooper, new species 
Plate 102, E, figures 38-49 
Large for the genus, transversely and broadly elliptical in outline; sides some- 
what narrowly rounded ; anterior margin nearly straight; costellate ; sulcus with 
5 to 6 costellae, fold with 6 to 7, and flanks with 11 to 12. Intercalations irregular. 
Pedicle valve moderately convex in lateral profile and with the posterior por- 
tion somewhat swollen; anterior profile gently convex. Umbo smooth, sulcus 
originating abruptly at the anterior side of the umbo about 4 mm. anterior to the 
beak ; sulcus deep and narrow, occupying about one-third to one-half the width 
at the front margin; flanks flat to gently convex and with moderate slopes. Inter- 
area long, curved, apsacline. 
Brachial valve moderately convex in lateral profile and with moderately swol- 
len umbo ; anterior profile strongly convex. Fold originating on the umbo, fairly 
strongly elevated to the anterior margin and with abrupt sides; flanks moder- 
ately swollen and with moderately steep slopes. 
