PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 575 
Measurements in mm.—Holotype, length 9.2, brachial length 8.5, width 10.2, 
hinge width 2.6, thickness 7.5. 
Type.—Holotype: 117993. 
Horizon and locality.— Bromide formation (Pooleville member—5o feet below 
the top) in Oklahoma: 0.1 mile southeast of the Observation Point on the Scenic 
Drive to Falls Creek, about I mile southeast of U. S. Highway 77, Murray 
County. 
Discussion.—This species is one of the partly costate species and is character- 
ized by 2 costae in the sulcus and 3 on the fold. It is suggestive of C. plicata 
(Schuchert and Cooper) but is a wider form with a somewhat wider apical angle. 
It is more strongly costate than C. obesa and C. ventricosa. 
CAMERELLA PARVA Billings 
Camerella parva Bituincs, Geol. Surv. Canada, Paleozoic fossils, vol. 1, p. 210, 1865. 
Types.—G.S.C. 
Horizon and locality—Table Head series (Logan’s divisions N, P) in New- 
foundland: 4 miles northeast of Portland Creek. 
CAMERELLA PENNSYLVANICA Cooper, new species 
Plate 118, E, figures 45-49 
Shell of about medium size for the genus, subpentagonal in outline; length and 
width about equal; posterolateral margins straight, forming an angle of 96°; 
sides rounded; maximum width at or near the middle; anterior margin trun- 
cated ; anterolateral margins short, gently curved. Surface paucicostate, posterior 
third smooth, anterior two-thirds costate, 4 costae on the fold, 3 in the sulcus, 
and 2 to 3 costae on the flanks. 
Pedicle valve less deep than the brachial one, moderately and fairly evenly con- 
vex ; anterior profile moderately convex ; umbonal and median regions inflated ; 
sulcus originating at about the middle, shallow and wide; tongue short, rounded ; 
flanks narrow, moderately swollen, and with steep slopes. Beak short and 
incurved. 
Brachial valve moderately convex but considerable curvature in the anterior 
half; anterior profile forming a highly convex dome with precipitous sides. Beak 
narrow; umbo and median region somewhat swollen; fold low and following 
closely the curve of the lateral profile; flanks fairly strongly swollen. 
~ Measurements in mm.—Holotype, length 10.8, brachial length 10.1, width 10.8, 
hinge width 1.6?, thickness 7.9. 
Type.—Holotype: 117142. 
Horizon and locality—Top of cherty beds in upper Row Park formation in 
Pennsylvania: In the field east of the railroad cut and on the north side of the 
Cumberland Valley RR., about 2 miles southwest of Marion, Chambersburg 
(15’) Quadrangle. 
Discussion.—This species is a partially costate form with obvious similarities 
to C. plicata (Schuchert and Cooper) but the apical angle is greater, the fold is 
