PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 595 
with moderately steep slopes. Spondylium long and slender, constricted more or 
less strongly near the middle. Tongue long, truncated but strongly serrate. 
Brachial valve with much greater depth than the pedicle valve and with un- 
even lateral profile, the umbonal region swollen but the median and anterior 
regions only moderately convex ; anterior profile strongly bowed. Umbonal re- 
gion swollen and protruding somewhat posterior to the posterior margin. Me- 
dian region swollen. Fold low, rounded in anterior profile, originating near the 
middle; flanks swollen, with precipitous slopes. Interior with long and deep 
cruralium, thickened adductor field, and no median septum. 
Measurements in mm.— 
Brachial Hinge 
Length length Midwidth width Thickness 
Holotype (brachial valve)............ ? 9.6 12.4 ? ? 
Paratype (pedicle valve 117150f)..... 11.2 ? 14.2 3:2 ? 
¢ VERS A Ae 11.0 10.5 12.8 3.9 7.4 
- crs fyrraregs6bys. J 33 0.5 9.0 10.7 32 4.7 
ia (On Des rH BEEGS SG) 8% sts 9.4 9.4 10.4 3.2 5.5 
Types.—Holotype: 117159b; figured paratypes: 117159a,c,d,f, 117161, 
111328e, 111333b, 111334b, 111336b, 111338, 111347a, 118013b-f; unfigured 
paratypes: 111333a,c,d, 111334a,c,d, 111336a,c, I17159e, 118013a. 
Horizon and locality —Effna formation in Virginia: At McNutt Quarry, 12 
miles southwest of Bland, Burkes Garden (15’) Quadrangle; Porterfield Quarry, 
5 miles east of Saltville, Maccrady (T.V.A. 218-NW) Quadrangle; Tilson Mill, 
16 miles northeast of Marion, Nebo (T.V.A. 223-NW) Quadrangle. 
Edinburg formation (Liberty Hall facies) in Virginia: 4 miles southwest of 
Bland, Bland County; 1.8 miles S. 4° W. of Bethel Church, 5.9 miles due east 
of Harrisonburg, Harrisonburg (15’) Quadrangle. 
Chatham Hill formation in Virginia: 1.2 miles S. 31° E. of Sharon Springs, 
Burkes Garden (15’) Quadrangle. 
Botetourt formation in Virginia: I mile northwest of Lexington, Lexington 
(15’) Quadrangle. 
Edinburg formation (Cyrtonotella zone) in Virginia: In the ravine at the 
switch about § mile east of Strasburg Junction, Strasburg (15’) Quadrangle. 
Lower 3 feet of the Pratt Ferry formation in Alabama: 0.2 mile southeast of 
Pratt Ferry, Blocton (15’) Quadrangle. 
Lower Benbolt formation in Virginia: On the south side of Mount Hagan 
School, Hilton (T.V.A. 197-NW) Quadrangle. 
Discussion.—The species is suggestive of Parastrophina hemiplicata of the 
New York Trenton but is less costate and less tumid than is usual in that species. 
It is distinguished from P. triangulata by its larger size and elliptical outline. 
Willard proposed the name Parastrophia rotundiformis for P. rotunda Win- 
chell and Schuchert from the Prosser of Minnesota and Iowa which was preoccu- 
pied by Atrypa rotunda Sowerby when that species was assigned to the genus 
Parastrophia. Willard referred his Virginia specimens to the Prosser species, 
but a number of important differences exist. The Virginia specimens belong to 
