PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 301 
Types.—Holotype: 110108a; figured paratype: 110108b. 
Horizon and locality—Oranda formation in Virginia: 4 mile west of Stras- 
burg, Strasburg (15’) Quadrangle; 0.6 mile northwest of Linville Station, 
Broadway (15’) Quadrangle. 
Discussion.—This species is characterized by its large size, deep sulcus, and 
the manner of implantation of the costae occupying the sulcus. It is of about 
the size of P. globularis but differs in having 4 costae in the sulcus rather than 
2. It suggests P. uniplicata, but that species has only 2 costae in the sulcus. 
PTYCHOPLEURELLA UNIPLICATA Cooper, new species 
Plate 49, H, figures 41-44 
Shell of about usual size for the genus, subrectangular in outline; sides nar- 
rowly rounded; anterior commissure sulcate; anterior margin nearly straight. 
Pedicle valve unequally convex in lateral profile, the posterior third somewhat 
concave, the anterior two-thirds flattened to gently convex; median costa raised 
to form a low fold; flanks flattened and sloping gently to the margins, marked 
by 6 costae. 
Brachial valve moderately convex in lateral profile with the maximum con- 
vexity at about the middle; anterior profile broadly convex but with the median 
region sulcate; sulcus deep and wide, occupied by 2 costae intercalated about 
I mm. anterior to the beak; flanks bounding sulcus fairly strongly convex ; pos- 
terolateral slopes steep. 
Measurements in mm.— 
alot pe .Cnedicle Walwe ELIOT 10a ) «:0's.s, hae aia spun: a aqe’gis 0 Meete 5.2 7.2 
Paratype (uractial valve LEOLIOD) .. Acc nas sae ene one anre 3.7 4.7 
Types.—Holotype: 110110a; figured paratype: I10110b. 
Horizon and locality.—Benbolt formation in Virginia: 14 miles west of Rye 
Cove, Clinchport (T.V.A. 188-NW) Quadrangle. 
Discussion.—This species is suggestive of P. sulcata from the Oranda forma- 
tion of Virginia, but the pedicle valve is more convex and the brachial valve has 
only 2 costae occupying the sulcus. The species is uncommon in the Benbolt 
formation. 
Family ANOMALORTHIDAE Ulrich and Cooper, 1936 
Orthacea having a sessile spondylium. 
Genus ANOMALORTHIS Ulrich and Cooper, 1936 
Anomalorthis Utricu and Cooper, Journ. Paleont., vol. 10, No. 7, p. 622, 1936; Geol. Soc. 
Amer. Special Pap. 13, p. 126, 1938. 
This genus is fairly common in the upper part of the Pogonip formation in 
Nevada and the Swan Peak formation of Utah. In Oklahoma Anomalorthis is 
abundant in the Oil Creek formation which is the correlate of the high Pogonip. 
It is also known from an undescribed species from the Joins formation of Okla- 
homa. This species is considerably coarser in its costellation than the Oil Creek 
species. 
