PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 405 
men. The median lobe always bears a strong carina, a feature not present in 
closely related genera such as Multicostella and Campylorths. 
As far as present knowledge goes, Valcourea typifies the Marmor, Ashby, and 
lower part of the Porterfield stages. It appears first in the upper part of the 
Upper Pogonip of Nevada, is abundant in the Crown Point formation of New 
York, the Lenoir of Tennessee, the Lincolnshire and Whistle Creek formations of 
Virginia. The stratigraphically highest specimens known occur in the lower part 
of the Bromide of Oklahoma, the lower Eureka of Nevada, and the Long Point 
series of Newfoundland. The genus is thus an excellent guide to a narrow band 
of the geological column. 
VALCOUREA ANGULATA (Phleger) 
Plectambonites angulatus PHLEGER, Bull. S. California Acad. Sci., vol. 32, pt. 1, p. 17, pl. 1, 
fig. I, 1933. 
Horizon and locality.—Barrel Spring formation California: In Barrel Spring 
Canyon, Inyo Mountains. 
VALCOUREA AUSTRINA Cooper, new species 
Plate 75, B, figures 6-27 
Valcourea strophomenoides Butts, Virginia Geol. Surv. Bull. 52, pt. 2, p. 41, pl. 73, figs. 1-8, 
1942. 
Shell fairly large for the genus; hinge forming the widest part; cardinal ex- 
tremities acute, occasionally auriculate. Anterior commissure broadly sulcate. 
Lateral margins faintly convex, sloping anteromedially. Anterior margin broadly 
rounded. Surface multicostellate, with 17 to 19 costellae in 5 mm. at the front 
margin of a valve 13 mm. long. Costellae narrowly rounded, strongly elevated. 
Pedicle valve gently convex in the posterior third to half ; gently to moderately 
deeply sulcate in the anterior half to two-thirds. Fold short, narrow, subcarinate, 
extending to about the middle of the valve where it is lost. Anteromedian sector 
depressed into a sulcus varying in depth on different individuals from barely 
perceptible to moderately deep. Flanks on each side of fold slightly convex in 
posterior half; flanks on each side of sulcus in anterior portion flat to gently 
concave. Cardinal extremities slightly depressed toward the brachial valve. In- 
terarea short, strongly apsacline. Pseudodeltidium short. 
Brachial valve moderately and evenly convex in lateral profile; in anterior 
profile the valve is humped up in the middle but flattens somewhat to the mar- 
gins by a gentle descent. Sulcus, short, shallow, inconspicuous in most cases, be- 
coming obsolete or faint in some specimens anterior to the middle. Anterior 
half to third thrown into a low, broad fold corresponding to the broad pedicle 
sulcate region. Flanks bounding fold and sulcus gently convex. Area between 
flanks and deflected cardinal extremities gently concave. 
Muscle field of pedicle valve large, subrectangular at the front ; diductor tracks 
large. Subperipheral rim strong. 
