PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 839 
larger costellae numbering 11 or 12 with short intercalations of large costellae 
at the front. These are separated from each other by 8 or possibly more fine 
costellae. Concentric elements are not conspicuous. The foramen is large. The 
brachial umbo is narrowly swollen and smooth, matching a smooth area in the 
vicinity of the pedicle foramen. 
Measurements in mm.—117610, length 8.1, brachial length 7.6, midwidth 10.9, 
hinge width 11.9, thickness 1.7, surface length 9.0, height 1.9. 
Figured specimen.—117610. 
Horizon and locality —Effna formation in Virginia: At Porterfield Quarry, 
5 miles east of Saltville, Maccrady (T.V.A. 218-NW) Quadrangle. 
DACTYLOGONIA sp. 6 
Plate 218, FE, figures 15, 16 
Shell large for the genus, wider than long, with the hinge forming the widest 
part. Pedicle valve gently convex in lateral profile, mostly so in the anterior 
quarter which forms an inconspicuous trail. Umbonal and median region some- 
what narrowly swollen to form a low but inconspicuous fold on the posterior 
three-quarters ; sides with short and steep slopes. Brachial valve concave, with 
the maximum concavity located just anterior to the middle; visceral region gently 
concave ; trail moderately long. 
Measurements in mm.— 
Brachial Hinge Thick- Surface Trail 
Length length Midwidth width ness length length 
Pedicle valve (117611a)... 12.5 ? 17.9 21.6 ? 14.0 2.0 ? 
Brachial valve (117611d)..  ? 14.3 24.6? 203 ? 16.0 6.0 
Figured specimen.—117611a; measured specimen: 117611d. 
Horizon and locality—Probably Benbolt formation (30 feet above the 225-foot 
marble) in Tennessee: At Eidson, Kyles Ford (T.V.A. 170-SE) Quadrangle. 
Discussion.—This species is a flatly convex one, not like any of those de- 
scribed. Its ornamentation is suggestive of D. alternata, but it is not so strongly 
geniculated. 
DACTYLOGONIA sp. 7 
Plate 217, G, figures 16-19 
Shell of about medium size for the genus, wider than long, transversely sub- 
rectangular. Surface marked by fine radial lines crossed by fine concentric 
lines. Visceral region of pedicle valve nearly flat in lateral profile, slightly con- 
vex in anterior profile. Place of geniculation about 8 mm. anterior to the beak; 
angle of geniculation about 115°. Trail short. Foramen large. Visceral region of 
brachial valve gently concave; umbo and median region of visceral area sulcate. 
Measurements in mm.—117612a, length 11.6, brachial length 10.2, midwidth 
17.2, hinge width ?, thickness 2.2, surface length 13.5, trail length 5.0. 
Figured specimens.—117612a,b. 
Horizon and locality—Whistle Creek formation in Virginia: Foot of Brushy 
