378 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
Types.—Holotype: 116943a ; figured paratypes: 116941a,b, 116942 ; unfigured 
paratypes: 116943b,c. 
Horizon and locality—Bromide formation (Mountain Lake member—middle 
of bed 6) in Oklahoma: At Rock Crossing of Hickory Creek, center sec. 35, 
T.5 S., R. 1 E., Carter County ; McLish Ranch, sec. 24, T. 1 S., R. 7 E., Johns- 
ton County; Nebo, Murray County. 
Discussion.—This is a small, somewhat transverse form with fairly strong 
costellae. It is not to be confused with either of the other two Oklahoma species 
which are much larger and squarer forms. The small Benbolt and Hogskin 
species are more finely costellate than G. uncinata. 
GLYPTORTHIS UNIFORMIS Cooper, new species 
Plate 43, E, figures 18-21; plate 46, C, figures 11-17; plate 40, I, figures 45-51 
Shell of about medium size for the genus, wider than long; hinge narrower 
than the shell width at the middle; sides and anterior margin gently rounded; 
anterior commissure rectimarginate ; surface multicostellate, costellae numbering 
42 to 44; imbrications 3 to the millimeter. 
Pedicle valve unevenly convex in lateral profile with the maximum convexity 
in the posterior half; anterior half somewhat flattened; anterior profile nar- 
rowly rounded in the median part with flat and steep slopes to the margins; 
umbonal region gently swollen ; median and anterior regions somewhat flattened ; 
posterolateral slopes fairly long and gentle. Interarea short, nearly catacline. 
Brachial valve moderately convex in lateral profile with the most convexity 
in umbonal region; anterior profile broadly convex but with a median depres- 
sion ; umbonal region somewhat swollen ; sulcus originating at the umbo, expand- 
ing anteriorly where it occupies somewhat less than half the width; sulcus de- 
fined by marginal costellae larger than the surrounding ones; sulcus occupied by 
8 costellae, 2 secondary, 4 tertiary, the remainder implanted on the margin, 
flanks bounding sulcus gently swollen. 
Measurements in mm.— 
Brachial Hinge 
Length length Width width Thickness 
Holotype aeridsntnee 10.6 10.5 13.0 12.2 6.1 
Paratype (116944a).. 9.9 9.6 12.0+- 11.4 5.5 
Types—Holotype: 116945a; figured paratypes: 116944a, 116945b, 116946a,b; 
unfigured paratypes: 116944b,c. 
Horizon and locality.—Benbolt formation in Virginia: West slope of hill 4 
mile east of Cedar Point School, Hilton (T.V.A. 197-NW) Quadrangle; Rye 
Cove, Clinchport (T.V.A. 188-NW) Quadrangle; north side of U. S. Highway 
19, 12 miles southeast of Hansonville Post Office, Brumley (T.V.A. 205-SE) 
Quadrangle. 
Benbolt formation in Tennessee: At the road corner southwest of Fleanor 
Mill ; roadside 1.6 miles northeast of Heiskell, Powell Station (T.V.A. 137-SE) 
Quadrangle. 
