892 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
larger ones separated by only I or 2 of the finer ones and numbering 2 or 3 to 
the millimeter at the front margin. Entire surface covered by fine fila which 
cancellate the finer costellae in the posterior and median parts, especially those 
of the brachial valve. 
Pedicle valve somewhat variable in lateral profile, usually fairly evenly and 
moderately convex and with the maximum convexity at the middle; anterior 
profile moderately domed. Beak small and inconspicuous ; umbonal region gently 
swollen; median region fairly strongly swollen with anterior and lateral slopes 
moderately steep. Pseudodeltidium short; interarea short. 
Brachial valve moderately concave in lateral profile, the maximum concavity 
somewhat anterior to the middle; umbo concave; median region gently concave 
to nearly flat; sides and anterior third deflected gently to moderately in the 
direction of the brachial valve. Chilidium large and convex. Interior with long- 
shafted, erect cardinal process lobes, slightly thickened notothyrial platform, 
shallow sockets, and subdued adductor ridges. 
Measurements in mm.— 
Brachial Hinge 
Length length Midwidth width Thickness 
Holotype ¢ is. 2 os ames 38.4 36.4 44.7 42.5 8.4 
Paratype (117764)... 30.6 36.9 48.0 ? 6.3 
Types.—Holotype: 117766a; figured paratypes: 117764, 117765; unfigured 
paratypes: 117766b. 
Horizon and locality—Bromide formation (Mountain Lake member) in Okla- 
homa: From the top of the green shale on the east side of the cut on Oklahoma 
Highway 18, 1.8 miles south of Sulphur, Murray County; 4 miles south of 
Davis, Murray County; Valcourea zone on Spring Creek, N} sec. 17, T. 2 S., 
R. 1 W., Murray County; Sowerbyites bed, same as preceding; west Spring 
Creek, east of Pooleville, Murray County; west of Nebo store, sec. 22, T. 2 S., 
R. 3 E., Murray County; middle of the east line of sec. 33, T. 2 S., R. 2 E., 
2 miles northeast of Springer, Carter County ; + mile west of U. S. Highway 77, 
sec,; 25, 1.2 5,.,.R.1, E., ‘Carter, County. 
Discussion——This species is characterized by large size, strong convexity, 
particularly in the anterior half, and moderately strong ornamentation. Of de- 
scribed species it is most like M. obesa of the Arline formation of Tennessee. It 
differs however in the lateral profile of the pedicle valve which is more evenly 
convex in the Tennessee species, in a less concave brachial valve and somewhat 
stronger ornamentation. The profile of M. bella is also less regular than that of 
M. champlainensis. 
MACROCOELIA CHAMPLAINENSIS (Raymond) 
Rafinesquina champlainensis RaAymMonp, Bull. Amer. Paleont., vol. 3, p. 37, pl. 18, figs. 5, 6, 
1902; Ann. Carnegie Mus., vol. 7, No. 2, p. 233, figs. 6-9, III. 
Horizon and locality—Crown Point formation in New York: At Crown 
Point, Chazy, Valcour Island, Plattsburg (15’) Quadrangle. 
Same formation in Vermont: On Isle la Motte, Plattsburg (15’) Quadrangle ; 
South Hero, Rouses Point (15’) Quadrangle. 
