PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 553 
Horizon and locality—Benbolt formation in Virginia: On east bank of a sink- 
hole 300 feet south of Lakeview Church on Virginia Highway 71, Moll Creek 
(T.V.A. 196-SE) Quadrangle; 0.2 mile south of the middle fork of Moccasin 
Creek, 14 miles south of Hansonville, Hansonville (T.V.A. 205-SW) Quad- 
rangle. 
Discussion.—This is a rare species in the Benbolt formation, where it occurs 
with the large O. multicostellata. The O. parva is typified by its small size and 
rotund form. In these respects it is like O. holstonensis, but its ribbing is too 
strong to be confused with that species. It is narrower, more rotund, and more 
strongly costellated than O. planiventra and O. recta. 
OXOPLECIA PENNSYLVANICA Cooper, new species 
Plate 104, C, figures 12-19 
Shell of about medium size for the genus, wider than long, broadly subellipti- 
cal in outline with rounded sides and short hinge. Strongly uniplicate. Flanks 
marked by 7 to 9 broad, subangular to rounded costae with intercalations near 
the anterior margin ; fold marked by 4 strong costae; sulcus marked by 3 major 
costae. 
Pedicle valve moderately convex in lateral profile and with the maximum 
curvature just posterior to the middle; anterior profile fairly strongly convex. 
Umbonal region swollen; sulcus originating 2 to 3 mm. anterior to the beak, 
narrow and deepening anteriorly ; tongue moderately long and narrowly rounded ; 
flanks bounding sulcus flattened to gently convex and with steep lateral slopes. 
Brachial valve fairly evenly and fairly strongly convex in lateral profile and 
with the umbonal region the most inflated part; anterior profile fairly strongly 
convex; fold originating on the anterior side of the umbo, narrow and fairly 
strongly elevated anteriorly where its sides are steep. Flanks moderately swollen 
and with steep lateral slopes. 
Measurements in mm.— 
Brachial Hinge 
Length length Width width Thickness 
PaOlOb ype ed PARE, VOL 10.4 10.0 12.9 7.4 8.1 
PoC G DE ck. vf Peictads. alae or.a 4 WON 13.9 12.7 15.5 sfh iP 9.0 
Types.—Holotype: 117119a; unfigured paratype: 117119b. 
Horizon and locality Dark shale originally referred to Rodman member of 
the Nealmont formation but now called Salona formation (base) in Pennsy]l- 
vania: At Bellefonte, Bellefonte (15’) Quadrangle; 4 mile north-northwest of 
Oak Hall, Bellefonte (15’) Quadrangle; old quarry 1 mile north-northeast of 
Bellefonte, Bellefonte (15’) Quadrangle; 4 mile north of Roaring Springs, Hol- 
lidaysburg (15’) Quadrangle. 
Discussion.—This species is one of the strongly costellated forms. It suggests 
O. magnaplicata more than any other species, but it is less umbonate and less 
convex in the brachial valve and has a more erect beak on the pedicle valve and 
a longer interarea. 
