PART I CHAZYAN AND RELATED BRACHIOPODS—-COOPER 995 
Types.—Holotype: 117337a; figured paratypes: 117337b, 117338c,d, 
117339a,b; unfigured paratypes: 117337c-j, 117338a,b,e. 
Horizon and locality—Cave Creek formation in Virginia: Along the L. and 
N. RR., 100 yards south of the water tank at Hagan, Rose Hill (T.V.A. 
161-NE) Quadrangle; on U. S. Highway 58, 34 miles east of Cumberland Gap, 
Wheeler (T.V.A. 153-SE) Quadrangle. 
Nealmont formation (upper shaly bed, Conradella fauna) in Lewistown (15’) 
Quadrangle, Pennsylvania: At southern (old) quarry of the National Lime 
Company, Naginey; Reedsville. 
Discussion —This species is suggestive of P. minuscula but may be distin- 
guished by its strongly rounded form and the deep but narrow sulcus of the 
brachial valve. It also suggests P. sp. 1 from Black River rocks in New York. 
This unnamed species is like P. sulcata in having a prominent sulcus on the 
brachial valve. The two may ultimately prove to be the same. 
PIONODEMA TENNESSEENSIS Cooper, new species 
Plate 162, B, figures 7-12 
Shell of about medium size for the genus, wider than long, subrectangular in 
outline ; lateral margins gently rounded ; anterior margin broadly rounded; hinge 
wide but narrower than the greatest shell width which is at about the middle. 
Anterior commissure nearly rectimarginate to gently uniplicate. Costellae mod- 
erately strong, fairly even, about 3 to the millimeter at the anterior margin. 
Pedicle valve having about the same depth as the brachial one, strongly con- 
vex in lateral profile, and strongly convex in anterior profile. Beak large, ele- 
vated, incurved; umbo swollen and with steep lateral slopes; median region 
swollen ; anterior slope convex and fairly steep. Median region slightly flattened 
in the anterior third; lateral slopes short and steep. Interarea long, curved, 
apsacline. 
Brachial valve fairly strongly convex in lateral profile with the maximum 
depth at about the middle; anterior profile broadly and fairly strongly convex ; 
umbo fairly deeply but narrowly sulcate, the sulcus extending to the middle or 
slightly anterior to that point; umbo and median region tumid; lateral slopes 
steep. 
Measurements in mm.— 
Brachial Hinge 
Length length Width width Thickness 
Boletype isu. chile ROe baa. 12.2 11.3 13.4 10.7 7.7 
Paratype: (117340) 2 andes 13.9 12.9 15.4 10.7 10.1 
a CIIZSUOE) oc rouse sk 11.7 11.0 13.7 9.8 6.0 
« Cnegsugd)) 6. HO), 22 oe 8.9 8.6 II.I 9.5 5.9 
Types.—Holotype: 117340a; figured paratype: 117340c; unfigured paratypes: 
117340b,d. 
Horizon and locality—Hermitage formation in Tennessee: On the east side 
of U. S. Highway 70S-41 near its junction with Spence Lane 4.2 to 4.3 miles 
southeast of Nashville, Hermitage (15’) Quadrangle. 
