PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 193 
Figured specimens.—116790a,b. 
Horizon and locality—Blackford formation (shale below the ““Mosheim” but 
above the Knox dolomite) in Virginia: About 3 mile east of Rocky Point, Natu- 
ral Bridge Special (15’) Quadrangle. 
OBOLUS ? sp. 3 
Plate 0, F, figure 16; plate 11, A, figure 1 
Fragments of a large oboloid brachiopod occur infrequently in the debris from 
the Pratt Ferry limestone which indicate a new species of this genus. The ex- 
terior is characterized by strong, elevated, narrowly rounded and crowded con- 
centric lines. Not enough details of the interior are preserved to permit definite 
identification with Obolus. 
Figured specimens.—116791a,b. 
Horizon and locality.—Pratt Ferry limestone in Alabama: 0.2 mile southeast 
of Pratt Ferry, Blocton (15’) Quadrangle. 
OBOLUS ? sp. 4 
Plate 9, H, figures 20-22; plate 11, D, figures 6-8 
Fragments of an oboloid brachiopod taken from the residues resulting from 
the solution of the Pratt Ferry limestone indicate a new genus. The specimens 
have the usual oboloid outline, but the exterior is marked by rounded concentric 
ridges arranged in quincunx. Where the ridges intersect, pits are formed which 
are also arranged in quincunx. Inside the brachial valve is a short triangular 
area like that of Obolus formed by a fold of the shell. 
Figured specimens.—116792a-c. 
Horizon and locality.—Pratt Ferry limestone in Alabama: 0.2 mile southeast 
of Pratt Ferry, Blocton (15’) Quadrangle. 
OBOLUS ? sp. 5 
Plate 2, D, figures 10, 11 
This is a large species, 16.1 mm. long by 12.5 mm. wide. The single speci- 
men is rather broadly oval in outline with the greatest width at about the middle. 
The greatest depth is in the posterior half. The ornamentation consists of nar- 
rowly elevated, concentric, often somewhat wavy lines. The spaces between the 
concentric lines are very narrow in the posterolateral slopes but widen as they 
cross the median part of the valve where they are distant by a space slightly more 
than the thickness of the concentric line. On the posteromedian region the dis- 
tance between the concentric lines is greater in the posterior half than in the 
anterior half. 
Figured specimen.—1 16772. 
Horizon and locality —Effna limestone in Virginia: In a pasture along Vir- 
ginia State Highway 114, 11 miles east of the junction with Virginia State High- 
way 311 near Haymakertown, Roanoke (15’) Quadrangle. 
