PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 731 
grooves in the lamellae. Where the lamellae have been stripped off, the orna- 
mentation consists of fine and strong costellae. About 11 strong costellae occupy 
a space of 5 mm. at the front, and from 3 to 7 fine costellae occupy the space be- 
tween the stronger ones. A few specimens with oblique wrinkles along the 
posterior margin. 
Pedicle valve only slightly convex in the young but becoming moderately con- 
vex in lateral profile in old shells. Greatest convexity just anterior to the middle. 
Anterior slope somewhat steeper than the posterior one. Umbonal region a little 
inflated, beak not prominent but protruding very slightly posterior to the pos- 
terior margin. Posterolateral slopes gently concave and moderately steep. Inter- 
area apsacline, slightly curved. 
Brachial valve gently concave with the greatest concavity in the anterior third 
or half. Umbo sulcate, sulcus poorly defined to about middle of valve where it 
is lost; cardinal extremities sulcate; interarea short, hypercline; lateral areas 
gently concave. 
Interior of pedicle valve with moderately strong callosities at the anterior ends 
of the diductor scars and located at or slightly anterior to the middle. Interior 
of brachial valve with strong median septum and well-developed lateral septa. 
Measurements in mm.— 
Brachial Hinge 
Length length Midwidth width Thickness 
Hypotype (117415g)......... Tr2 10.0 17.4 21.0 22 
i (itT4068)) 0a. 3 12.6 5 17.5 17.8+ 2.8 
bf ( TEEAGGE A, 80). 5 fk 9.9 8.7 13.4 14.8+ 2.3 
c (UI74008 beni oO. ..% 10.5 9.6 17.0 18.9+ 2.8 
os EE ZAC 2, 8 ias8 13.2 II.9 19.9 23.0 ? 
Types.—Figured hypotypes: 111796a-c,e,f, 117409a-c,e, I17410a, I17411Ib, 
117412b, 117413a,b, 117414a-c, 117415a,b,e,¢,i,j, 123252a,b; measured hypotypes 
111496a,f. 
Horizon and locality——Lincolnshire formation in Virginia: Near Goodwins 
Ferry on New River, Giles County ; 1,000 feet north of road along Buffalo Creek, 
24 miles west of Murat, Rockbridge County; at the Dunkard Church, 6 miles 
north of Buchanan, Natural Bridge Special (15’) Quadrangle; 1.8 miles S. 4° 
W. of Bethel Church, 5.9 miles due east of Harrisonburg, Harrisonburg (15’) 
Quadrangle; 4 mile northeast of the junction of Virginia County Highways 602 
and 725, Augusta-Rockbridge County line. 
Same formation in Tennessee: In Clinch Valley, 0.2 mile southwest of Shiloh 
Church, near the center of the northwest subquad., Pressmens Home (T.V.A. 
171-NE) Quadrangle ; # mile southwest of Mount Eager Church, Hogskin Val- 
ley, Powder Springs (T.V.A. 154-SW) Quadrangle; 90 to 120 feet above the 
“Mosheim” limestone on U. S. Highway 25E, 1 mile north of Indian Creek, 
Howard Quarter (T.V.A. 162-NW) Quadrangle; on U. S. Highway 25E north 
of Thorn Hill, Avondale (T.V.A. 162-SW) Quadrangle; 4 mile north of Eidson, 
Kyles Ford (T.V.A. 170-SE) Quadrangle; at Red Hill north of road 44 miles 
west-southwest of Thorn Hill, Avondale (T.V.A. 162-SW) Quadrangle. 
