PART | E CHAZYAN AND RELATED BRACHIOPODS—COOPER 539 
TRIPLESIA sp. 1 
Plate 121, D, figure 13 
A single imperfect pedicle valve of this unusual genus was taken in the black 
limestones of the Whitesburg formation at Bulls Gap. The specimen is 6.7 mm. 
long and has the same distance as its maximum width. The sulcus originates at 
about the valve middle and widens and deepens rapidly. The sulcus is bounded 
by short, somewhat obliquely curved folds. The beak is moderately long and 
shows two short divergent dental plates through the translucent shell. The 
median region is moderately swollen. 
Figured spectmen.—117097. 
Horizon and locality.—Whitesburg formation in Tennessee: 14 miles west of 
Bulls Gap, Bulls Gap (T.V.A. 171-SE) Quadrangle. 
Genus OXOPLECIA Wilson, 1913 
Oxoplecia Witson, Victoria Mem. Mus. Bull., vol. 1, pp. 81-86, 1913.—ULricH and Cooper, 
Journ. Paleont., vol. 10, No. 5, p. 337, 1936. 
OXOPLECIA ABNORMIS Cooper, new species 
Plate 104, G, figures 39-44 
Shell small, transversely elliptical in outline with narrowly rounded lateral 
margins and truncated front margin. Greatest width at about the middle; unipli- 
cate. Surface costellate, with 2 costellae occupying the sulcus and 3 on the fold. 
Flanks marked by 8 costellae produced by the bifurcation and implantation of 2 
or 3 primary costellae on each side of the fold and sulcus. 
Pedicle valve gently convex in lateral profile with the greatest curvature in the 
umbonal region. Sulcus originating just anterior to the umbo and widening an- 
teriorly to occupy about one-third the valve width at the front margin. Flanks 
bounding sulcus gently convex; posterolateral slopes to cardinal extremities 
steep. Interarea apsacline, moderately long and narrow. 
Brachial valve strongly convex in lateral profile and with the greatest con- 
vexity in the posterior half. Umbonal region full but not conspicuous. Fold origi- 
nating just anterior to the umbo, low throughout its length. Flanks bounding 
fold gently convex in profile, with moderate slopes to the margins. 
Measurements in mm.—Holotype, length 8.8, brachial length 7.8, width 13.4, 
hinge width 7.0?, thickness 5.8. 
Type.—Holotype: 110842. 
Horizon and locality—Effna formation in Virginia: I mile east of Tilson Mill, 
16 miles northeast of Marion, Nebo (T.V.A. 223-NW) Quadrangle. 
Discussion.—This species is best distinguished by its narrowly and trans- 
versely elliptical outline which sets it off from any other species described herein. 
The species occurs with Oxoplecia holstonensis but differs from that species in 
ornamentation, development of fold and sulcus, and convexity of valves as well 
as outline. 
