PART CHAZYAN AND RELATED BRACHIOPODS—COOPER 707 
field. Adjustor scars long and slender, located on the outside margin of the 
muscle field just inside the lateral ridge. Diductor impressions long and slender 
extending for fully a third the length of the valve. Adductor impressions form- 
ing an oval field with the pointed end extending into the callus filling the posterior 
end of the delthyrial cavity. Pallial impressions deeply entrenched in the shell ; 
the main vascula media extending from the anterior ends of the diductor scars 
for a short distance and then branching. Vascula media separated by a low, wide 
thickening of the shell. A second pallial trunk originates at about the anterior 
end of the adjustor scar. Ovarian impressions small. 
Brachial interior with a stout median ridge extending to about the middle of 
the valve where its end is thickened and elevated. Brachial processes short and 
stubby (?) ; notothyrial cavity filled by callus and notothyrial platform occupied 
by a large cardinal process with bulbous shaft when viewed from the pedicle 
valve side. In posterior view the process is a thin, elevated median ridge inti- 
mately grown with the chilidium. Adductor impressions elongate, thickened at 
the front edge of the anterior scar which lies inside the posterior smaller scar. 
A pallial trunk extends anteriorly on each side of the median ridge. 
Measurements in mm.— 
Brachial Hinge 
Length length Width width Thickness 
PAOUILV BS | ois cies ec idesete oe vcore 10.5 9.0 11.6 13.6 1.5 
Paratype  CLUTOZOL) cas «sie oles wc 9.1 8.3 12.3 14.8 1.8 
ee ( BEFO7O-1) 09...) 22 22. 12.3 ? 13.6 16.4 ? 
, (7573812) sree .7 12.4 11.9 14.0 15.5 2.1 
Types——Holotype: 111070m; figured paratypes: 111070f-i,p, 117380, 
117381a-c; unfigured paratypes: 111070a-e,j,k,n,o, 117381d-n. 
Horizon and locality—Arline formation on Concord (T.V.A. 138-SW) and 
Louisville (T.V.A. 138-SE) Quadrangles in Tennessee: 4 mile southeast of 
Friendsville ; 5 miles southeast of Knoxville; 100 yards southwest of the Negro 
Cemetery, 4 mile northeast of Friendsville; 1 mile northeast of Friendsville. 
Fetzer tongue in Tennessee: At the road bend 0.6 mile south-southeast of 
Harrison-Chilhowie Academy, Walden Creek (T.V.A. 156-SW) Quadrangle ; 
1.3 miles south of Sevierville, Pigeon Forge (T.V.A. 156-SE) Quadrangle. 
Arline formation in Virginia: In the quarry at Marion, Marion (T.V.A. 
218-SE) Quadrangle. 
Discussion.—This species is characterized by moderate size, thin shells, fairly 
strongly resupinate profile, and generally a somewhat narrowly rounded anterior 
margin as well as a wide and often alate hinge and cardinal extremities. It differs 
from P. subtransversa in its more elongate outline and from P. resupinata in its 
thinner shell, generally smaller size, and more narrowly rounded anterior margin. 
PALAEOSTROPHOMENA SUBTRANSVERSA Cooper, new species 
Plate 168, C, figures 11-23 
Shell wider than long, with the contour of Strophomena; cardinal extremities 
acutely angular, auriculate; anterior margin broadly rounded; lateral margins 
