PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 249 
margin and moderately convex anterior margin; anterior profile with gently con- 
cave sides; apical angle 35° to 40°; apex truncated, perforated by a minute 
foramen. Pseudointerarea broad and flat ; intertrough narrow and extending for 
the length of the valve. 
Measurements in mm.—Holotype, length 1.5, width 2.0, thickness 3.5. 
Type.—Holotype: 116812. 
Horizon and locality—Botetourt formation in Virginia: Field on the south 
side of the road, 0.2 miles east of Strasburg Junction station, Strasburg (15’) 
Quadrangle. 
Discussion—This species is distinguished from all the other conical forms 
described by the extreme thickness or elongation of the valve in the direction of 
the thickness. The beak is long and slender and the sides of the valve concave. 
It is probable that this form and C. alta belong to a new genus. Correct assign- 
ment will have to await the discovery of the brachial valve. 
This species is suggestive of C. ? alta but differs in its larger size and the 
slight curvature of the pedicle valve in lateral profile. 
CONOTRETA APICALIS Cooper, new species 
Plate 17, B, figures 15-28 
Shell of about medium size for the genus, thick, dull dark brown in color; 
obliquely conical in outline with the posterior side flattened ; shell margin nearly 
circular; height or thickness equal to the width. Surface marked by growth 
undulations and fine concentric lines. 
Pedicle valve with apical angle of 43°; lateral profile with strongly convex 
anterior margin; anterior profile with slightly convex lateral margins; beak 
acutely pointed; foramen minute, apical. Posterior margin in lateral profile 
gently concave; width of pseudointerarea about half the valve width. 
Brachial valve slightly longer than wide; gently convex in lateral profile with 
the greatest convexity located in the anterior part of the posterior third of the 
valve; anterior two-thirds somewhat flattened; anterior profile broadly convex, 
somewhat flattened medially and with short, gently sloping lateral slopes. 
Pedicle interior: Foraminal cavity deep; pallial sinuses numbering 3 on each 
side ; callosity just anterior to foraminal cavity small. Brachial interior with short 
and narrow triangular depression; propareas small; median ridge extending 
nearly to front margin, highest about one-half the length anterior to the posterior 
margin where it attains a sharp point. Posterior part of septum with a crescent- 
shaped smooth area located just anterior to the triangular depression. 
Measurements in mm.— 
Length Width Thickness 
Holotype (pedicle valve) ......... a 3.4 3.1 (posterior surface) 
Paratype (brachial valve 116813c). 2.5 2.6 ? 
Types.—Holotype: 116813a; figured paratypes: 116813b-g. 
Horizon and locality —Pratt Ferry formation (lower 3 feet) in Alabama: 0.2 
mile southeast of Pratt Ferry, Blocton (15’) Quadrangle. 
