PART 1 CHAZYAN AND RELATED BRACHIOPODS—COOPER 413 
Measurements in mm.— 
Brachial Hinge 
Length length Width width Thickness 
1s 2S 9h cayerensteins el omnia grad tai 6.9 6.9 10.8 12.3 1:2 
Paratype “Cr r6o70c)o. . LP Basle 9.0 9.6 13.1 15.9 1.1 
K (pedicle valve 116970j) 7.7 ? 12.6 15.4 ? 
Types.—Holotype: 116970e; figured paratypes: 116970a,b,d,f,g,1,j ; unfigured 
paratypes: 116970c,h. 
Horizon and locality —Tulip Creek formation (152 feet above the basal sand) 
in Oklahoma: On the first creek east of U. S. Highway 77, SE{NENE sec. 25, 
T.2S., R.1E., Carter County ; West Spring Creek, 24 miles east of Pooleville, 
Murray County. 
Discussion—This species occurs in abundance in a few places. Generally 
young transverse specimens are far more abundant than adults. In the young 
form the species suggests V’. transversa, but it is generally smaller and less 
convex. 
VALCOUREA TRANSVERSA Cooper, new species 
Plate 72, D, figures 22-31; plate 76, B, figures 11-14 
Shell of about medium size for the genus; wider than long with the length 
ranging from one-half to two-thirds the width at the hinge; hinge wide, forming 
the widest part, often mucronate and with acute extremities ; sides oblique, nearly 
straight; anterior margin broadly curved; anterior commissure rectimarginate ; 
surface marked by costellae of unequal size, the large ones scattered among the 
finer ones, 3 or 4 in I mm. at the front margin; costellae crossed by strong, 
elevated concentric fila about 8 to the millimeter. 
Pedicle valve evenly and fairly deeply concave, with the greatest depth in the 
median region; umbo sharply folded; fold low, distinct to middle but obscure 
from there to anterior margin; posterolateral extremities just anterior to pos- 
terior margin slightly sulcate ; posterior margin forming a thickened and elevated 
rib; interarea long, strongly apsacline; pseudodeltidium long and strongly 
elevated. 
Brachial valve unevenly convex in lateral profile, the posterior third flattened 
to slightly concave, median third strongly convex, anterior third gently convex ; 
anterior profile broadly convex with the median region narrowly sulcate ; umbo 
flat to gently concave, fairly deeply and narrowly sulcate; sulcus extending for 
two-thirds the length but disappearing on the anterior slope; median region in- 
flated ; flanks somewhat depressed and with gentle slopes. 
Pedicle interior with deeply impressed muscle area with thickened margins, 
extending nearly to middle; brachial interior with stout brachiophores supported 
by callus deposit ; cardinal process with stout shaft and high-crested myophore. 
Measurements in mm.— 
Brachial Hinge 
Length length Width width Thickness 
Higigtyperceak ees.) Saas 9.8 10.2 15.2 19.0 2.5 
Paratype (116072b) |. 95 2s ashes 11.4 11.4 17.7 18.5 3.5 
“fi (BIG972a)) siete eres 11.9 11.9 17.5 19.6 3.6 
