436 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
Pedicle valve in lateral profile gently convex in posterior half but gently to 
moderately concave in the anterior half. Beak inconspicuous, umbo slightly 
swollen ; fold variable extending anteriorly from beak to front margin or disap- 
pearing in the anterior half. Fold generally marked by a median costella stronger 
than surrounding ones. Region in front of cardinal extremities gently concave; 
flanks of shell separating concave median area from cardinal extremities generally 
gently convex. Interarea strongly apsacline to nearly procline, about equal in 
length to the interarea of the brachial valve. Delthyrium open. 
Brachial valve moderately convex in lateral profile; moderately convex in an- 
terior profile with center sulcate. Sulcus originating and generally extending as 
a shallow and narrow depression anteriorly to the front margin but disappearing 
posterior to the front margin in some specimens. Flanks bounding sulcus gently 
swollen with long gentle concave slope to cardinal extremities and with mod- 
erate slopes to the anterior margin. Interarea long, orthocline to apsacline and 
extending posterior to the pedicle beak. 
Pedicle interior with muscle field about as long as wide, not deeply impressed ; 
pallial marks not well developed. Brachial interior with short median ridge; 
ponderous cardinal process and strong development of excess shell about the 
cardinal process and brachiophores. 
Measurements in mm.— 
Brachial Hinge 
Length length Width width Thickness 
EVOMSEMOIE: 5 ik win nie tas si ibattinvwists cee 21.2 22.7 26.6 20.4 8.8 
Paratype (110484a).......... 20.3 21.0 25.0 28.4 8.1 
4 (104841). f 0 bc) 52 6.2 6.6 7.3 7.5 2.0 
. (TIO4B4S). omrsag st. 3 8.1 8.3 II.4 12.4 3.0 
% (1104840) sate an tee U7, 18.5 22.0 28.4 6.4 
° (IOASAD) nce. 8 ety 23.0 24.5 20.7 32.4 ey} 
* (OST Oa) Perrys ee 18.0 18.9 22.4 20.7 7.6 
3 CHTOSIOR)Y ne 21.0 22.5 24.4 22.2 7.5 
Types.—Holotype: 98212a; figured paratypes: 98212{,g, 110484b, 110488a,b, 
110519a,f, 116997b, 116998a; unfigured paratypes: 98212b-e, 110484a,c-1, 
11051Qb-e,g-t, 116997a,c,d. 
Horizon and locality—Wardell formation (shaly facies) in Tennessee: 1.1 
miles northeast of Lee Valley, Lee Valley (T.V.A. 171-NW) Quadrangle; 4 
mile west of Dodson Creek on the road from Acuff to Tennessee Highway 33, 
Maynardville (T.V.A. 145-SE) Quadrangle; valley west of Copper Ridge on 
Rogersville-Sneedville road, Lee Valley (T.V.A. 171-NW) Quadrangle; 4 miles 
northwest of Rogersville, Pressmens Home (T.V.A. 171-NE) Quadrangle; 
Davis store west of Eidson, Kyles Ford (T.V.A. 170-SE) Quadrangle. 
Dryden formation on Tazewell (T.V.A. 154-NE) Quadrangle in Tennessee: 
Lone Mountain to Tazewell road, 14 miles northeast of Lone Mountain; road 
along Little Sycamore Creek, 0.35 mile northeast of Halls School. 
Same horizon on Clinchport (T.V.A. 188-NW) Quadrangle in Virginia: At 
Mannville School; 20 feet below top on U. S. Highway 58, 4 mile west of Danl- 
