PART,,.£ CHAZYAN AND RELATED BRACHIOPODS—COOPER 557 
interspaces of about the same width as the costellae. Concentric fila numerous, 
about 5 in 1 millimeter near the middle. 
Pedicle valve moderately convex in lateral profile and with the greatest con- 
vexity in the umbonal region; sulcus originating 3 to 4 mm. anterior to the 
beak, widening gradually to the front margin where it occupies about one-half 
the width. Flanks bounding sulcus flattened, slopes to lateral margins moder- 
ately steep. Tongue moderately long, broadly rounded. Beak low, strongly in- 
curved; interarea moderately long ; apsacline. 
Brachial valve moderately convex in lateral profile but with a narrowly rounded 
umbo; anterior profile broadly and moderately convex; beak small, protruding 
slightly beyond the posterior margin. Fold originating on the strongly curved 
umbo, heightening anteriorly but only moderately elevated at the front margin. 
Flanks moderately convex but with steep slopes to the margins. 
Interior: Pedicle valve with nearly obsolete dental plates, and delthyrial cavity 
nearly filled with callus; foramen functional, minute; diductor scars flabellate. 
Brachial valve with long, curved cardinal process. 
Measurements in mm.— 
Brachial Hinge 
width 
Length length Width Thickness 
MMECLOEV PO sie b tiia.vs oo asia Ss5'e 8.8+ 8.7+ 12.8 ? 6.4 
Hypotype *( 817127). 00. ss 12.2 II.0 T5a0 10.0 9.5 
i (GO7500a) li. FPR 17.0 16.3 22.5 15.5 14.1 
Types.—Lectotype: 66175 ; figured hypotypes: 97599a, 117127; figured para- 
type: 117128. 
Horizon and locality—Lectotype from Chambersburg (Sinuites bed) 
(=Oranda in part) in Pennsylvania: 1 mile south of St. Thomas, Mercersburg 
(15’) Quadrangle; 1 mile north of Guilford Springs, 24 miles southwest of 
Chambersburg ; 34 miles north of Greencastle, Chambersburg (15’) Quadrangle ; 
Carlisle, Carlisle (15’) Quadrangle. 
Oranda formation in Virginia: Along the railroad 4 mile west of Strasburg ; 
U. S. Highway 11, 2 miles southeast of Strasburg; on Virginia Highway 55, 
0.4 mile west of U. S. Highway 11, north edge of Strasburg, Strasburg (15’) 
Quadrangle; north of the road 0.6 mile northwest of Linville Station, Broadway 
(15’) Quadrangle; Strickler Farm, junction of Virginia County Highways 961 
and 962, west of Edinburg; below the dam on the north branch of the Shenan- 
doah River, 14 miles north of Edinburg; on Bowman Farm, east of U. S. High- 
way II, about 1 mile south of Woodstock, Edinburg (15’) Quadrangle; 13 
miles east-northeast of Long Glade; just west of the junction of Virginia County 
Highways 617=910, and 777, 900 feet north-northwest of Green Mount Church, 
Broadway (15’) Quadrangle; Cedar Grove Church, 200 yards on Virginia 
County Highway 616 east of U. S. Highway 11, 35 miles southwest of Mount 
Jackson, Mount Jackson (15’) Quadrangle. 
Discussion.—The type lot of this species consists of four cotypes. Examina- 
tion of the specimens makes it clear that they come from different strata and 
that they are not the same species. One of the cotypes (pl. 49, fig. 11.) is said 
