PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 961 
Brachial valve gently convex in lateral profile ; anterior profile broadly convex, 
flattened in the median region and gently depressed at the middle ; umbo sulcate ; 
sulcus narrow but moderately deep, extending only to the valve middle ; anterior 
slope long, moderately steep; median region somewhat swollen; lateral slopes 
short but moderately steep. 
Measurements in mm.— 
Brachial Hinge 
Length length Width width Thickness 
Holotype WPis.’. 232 «5 11.3 10.1 II.I 9.0 5.2 
Paratype (117347a)... 8. 7.3 8.7 6.9 4.2 
Types——Holotype: 117350a; figured paratypes: 117347b, 117348a, 117349, 
117350b,c; unfigured paratypes: 117347a, 117348b, 117350d,e. 
Horizon and locality—Benbolt formation (lower) in Virginia: On the south 
side of Mount Hagan School, Hilton (T.V.A. 197-NW) Quadrangle; east bank 
of sinkhole, 300 feet south of Lakeview Church on Virginia Highway 71, Moll 
Creek (T.V.A. 196-SE) Quadrangle; 0.2 mile south of the middle fork of 
Moccasin Creek, 14 miles south of Hansonville, Hansonville (T.V.A. 205-SW) 
Quadrangle; 4 mile southeast of Richpatch, Eagle Rock (15’) Quadrangle. 
Discussion—At present no other species of this genus is known with which 
E. biconvexum can be compared. The species is easily recognized by its form, 
fine costellae, thick valves, and ponderous cardinalia. 
CRISTIFERINA Cooper, new genus 
(Latin crista, crest; fero, bear) 
Shell smail, less than 4 inch in width, subelliptical to subcircular in outline ; 
valves unequally convex, the brachial valve having less depth than the pedicle 
valve; anterior commissure gently sulcate; surface multicostellate, narrowly 
rounded, and strongly elevated, costellae increasing in number by intercalation. 
Pedicle valve with stout teeth having large fossettes; dental plates short and 
stout ; delthyrial cavity deep ; muscle area heart shaped; diductor scars protrud- 
ing anterior to the ends of the dental plates and forming 2 lobes at the front of 
the muscle field. Traces of somewhat divergent vascula media separated by a 
low median ridge appear in some specimens. 
Brachial interior with moderately long bladelike brachiophores having short, 
sharp crura protruding from their inner end; brachiophores supported by strong 
swelling of the notothyrial platform; sockets deep; no fulcral plates; cardinal 
process with short, grooved shaft, expanded myophore; surface of myophore 
with large, recurved median plate; median ridge strongly elevated. Adductor 
field small. 
Genotype.—Cristiferina cristata Cooper, new species. 
Discussion.—This genus is best recognized by its small size, strong costellae, 
deep pedicle valve and moderately convex brachial valve, and the character of 
the cardinalia, particularly the bizarre development of the cardinal process. As 
far as known the genus is rare. 
The exterior of Cristiferina is strongly suggestive of Paucicrura of the Decorah 
