PART 5 CHAZYAN AND RELATED BRACHIOPODS—COOPER 831 
Types.—Holotype: 117942a; figured paratypes: 117942c,d; unfigured para- 
type: 117942b. 
Horizon and locality—Lower Ward Cove formation in Tennessee: 3 mile 
southwest of Mount Eager Church, Hogskin Valley, Powder Springs (T.V.A. 
154-SW) Quadrangle. 
Discussion—This species is characterized by its angular lateral extremities, 
short geniculated area and distant costellae in a mat of fine cancellated costellae. 
This species is most like D. incrassata (Hall) of the New York Chazyan but is 
more distantly and more delicately ornamented. It is less strongly geniculated 
and less square in the cardinal extremities than D. geniculata, and differently 
ornamented. 
DACTYLOGONIA MARMORATA Cooper, new species 
Plate 217, F, figures 11-15 
Shell small for the genus, wider than long and with the hinge forming the 
widest part; sides gently rounded; anterior margin broadly rounded. Surface 
marked by a mat of fine costellae cancellated by fine concentric lines ; a few larger 
costellae 5 or 6 in number are present. More or less prominent concentric 
wrinkles mark the visceral region. 
Pedicle valve with visceral region extending for 5 to 7 mm. from the beak, 
gently convex in lateral profile ; angle of geniculation variable, usually near 95° ; 
trail variable, usually fairly long and steep. 
Visceral region of brachial valve gently concave; umbo concave; deepest at 
place of geniculation ; trail not so long as that of the pedicle valve. 
Measurements in mm.— 
Brachial ‘ Hinge Thick- Surface Trail 
Length length #Midwidth width ness length length 
Holotype“). 810. fis es 8.9 ? 11.8 12.9 ? 0.5 1.5 
Paratype (123265a)... 6.9 ? 10.6 12.1 ? 7.5 2.0 
" 123 2650)iiee) con 8.7 igs 16.7 ? 10.0 2.0 
* (123265d)... 8.4 ? 11.9 12.7 ? 11.0 3.0 
Types.—Holotype: 123265); figured paratypes: 123265a,c,d; unfigured para- 
type: 123265e. 
Horizon and locality—Murat formation in Virginia: 2 miles northwest of 
Lexington, Lexington (15’) Quadrangle. 
Discussion.—This is a species of moderate size somewhat resembling D. in- 
crassata or D., extensa in form. It differs from both of them in having moder- 
ately strong but irregular wrinkles on the visceral disk area. Dactylogonia palus- 
tris is also a somewhat wrinkled form but differs in its smaller size, more regular 
outline, shorter trail, and smaller visceral disk region. 
DACTYLOGONIA OBSOLETA (Butts) 
Plate 217, K, figures 32-34 
Rafinesquina obsoleta Butrs, Alabama Geol. Surv., Special Rep. 14, pl. 26, figs. 20, 30, 1926. 
Only two specimens of this species are known that preserve the outline and 
profile of the shell. As both are coarsely silicified, description of details of the 
