636 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
Tennessee Highway 16, 3.6 and 5.1 miles northwest of Shelbyville; 3 miles 
southwest of Woodbury. In Sequatchie Valley, Bledsoe County, Tenn.: Cedar 
Ridge, 1 mile southeast of Litton, Sequatchie Valley, Pikeville Special (15’) 
Quadrangle. In Smith County, Tenn.: At the east end of the bridge on U. S. 
Highway 70N over Round Lick Creek at Rome. In Maury County, Tenn.: At 
Columbia. 
Camp Nelson formation in Kentucky: At 140 to 150 feet, High Bridge, 
Harrodsburg (30’) Quadrangle. 
ROSTRICELLULA COSTATA Cooper, new species 
Plate 130, B, figures 9-17 
Camarotoechia plena ? Butts, Alabama Geol. Surv., Special Rep. 14, pl. 22, figs. 4, 5, 1926. 
Shell small for the genus, triangular to subpentagonal in outline; valves sub- 
equal in depth; beak slightly obtuse; sides nearly straight to slightly rounded ; 
anterolateral extremities narrowly rounded and forming location of greatest 
width ; front margin truncated. Surface costate, 3 costae generally occupying the 
sulcus, 4 on the fold, and 6 on the flanks. 
Pedicle valve moderately convex in lateral profile with the greatest convexity 
located in the umbonal region ; posterior half very gently convex ; sulcus originat- 
ing about 3 mm. anterior to the beak, broad and shallow, occupying about two- 
thirds the width at the front ; tongue short, narrowly rounded toward the brachial 
valve, serrate but square in front. Sulcus bounded on each side by a strongly 
elevated angular costa higher than the costae of the sulcus and the flanks, which 
are narrow and steep-sided. 
Brachial valve moderately convex in lateral profile with the greatest curva- 
ture located in the anterior part. Posterior half sulcate with the sulcus broad 
and shallow and bounded by narrowly rounded flanks. At about the middle, 
24 mm. from the beak of the brachial valve a fold develops out of the posterior 
sulcus in the form of 2 depressed costae flanked by a costa strongly elevated 
above those of the fold and the flanks on each side. Slopes to margins nearly 
vertical and flat-sided ; flanks bounding sulcus narrowly rounded. 
Interior: A single specimen shows a well-developed muscle field in the pedicle 
valve located anterior to the short dental plates. The field is trapezoidal in out- 
line with a straight front margin. Individual scars not distinguishable. 
Measurements in mm.— 
Brachial 
Length length Width Thickness 
I GIOEV IG! 2s cicoeipinta ny ae pinto cin es Mat 5.2 4.9 5.6 4.2 
Paratype’ (71486) -253.0) Jghee ta 6.0 5.5 5.9 5.0 
a CYUTACODN tre nate tis eee es 6.0+ 5.9 6.6 4.0 
Types.—Holotype: 111460a; unfigured paratype: 111460b; measured para- 
type: 71486. 
Horizon and locality—Lenoir formation in Alabama: 2 miles west-southwest 
of Pratt Ferry, Blocton (15’) Quadrangle. 
