PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 437 
boone Yard on road from Gate City to Speers Ferry; Lloyd Carter’s barn, 0.8 
mile northeast of school at Rye Cove; near new school at Rye Cove. 
Discussion—This species is characterized by its unequal costellae, generally 
well developed alate cardinal extremities, strong fold and sulcus for the genus, 
and the generally compressed form. No other species has this combination of 
characters. Chaulistomella superlata has some resemblance, but it is generally 
a proportionally wider species and has a more concave pedicle valve. None of 
the Oklahoma species is very similar because they have much more convex 
brachial valves and are generally not so strongly alate. 
This species is quite variable particularly in the hinge region. Some speci- 
mens are fairly quadrate in outline and have nearly rectangular or obtuse cardi- 
nal extremities. They are apparently extremes, prevented from developing their 
normal alate form by overcrowded living conditions. 
CHAULISTOMELLA LEBANONENSIS Cooper, new species 
Plate 65, E, figures 21-30; plate 60, E, figure 23 
Shell of about the usual size for the genus, about one-third wider than long. 
Cardinal extremities approximately a right angle, usually strongly rounded. 
Sides nearly straight or moderately strongly rounded; anterior margin gently 
rounded to subtruncate. Anterior commissure broadly uniplicate. Surface multi- 
costellate, 10 to 12 costellae occupying a space of 5 mm. at the front margin of 
an adult. Costellae narrowly rounded and separated by furrows narrower than 
the costellae. 
Pedicle valve gently convex in the umbonal region but flatly convex anteriorly ; 
fold varying from scarcely visible to fairly strong and extending from beak to 
anterior margin. Anterolateral regions flattened. Interior with large quadrate 
muscle area having large adjustor scars and large diductor impressions. Pallial 
impressions not strong. 
Brachial valve fairly strongly convex in lateral profile with the most convex 
part in the posterior half; anterior profile strongly convex with steep, flattened 
to slightly concave sides. Sulcus well defined to nearly obsolete. Posterolateral 
slopes steep; cardinal extremities deflected. Interarea shorter than the pedicle 
one, apsacline, not extended posterior to the posterior margin of the pedicle valve. 
Measurements in mm.— 
Brachial Hinge 
Length length Width width Thickness 
Holptype 's. eses fie TPs 17.9 18.0 23.6 19.6 9.2 
Paratype (pedicle valve 110533a).... 18.9 ? 24.9 22.5 ? 
re [nS I re? Pe 17.0 17.3 21.8 ? 6.0 
Types Holotype: 84024a; figured paratypes: 110523a, 110524a, 110533a, 
110534a; unfigured paratypes: 27286a, 84024b, 110523b, 110524b, 110533b-e, 
110534. 
Horizon and locality—Lebanon formation in Tennessee: At Lebanon, Wilson 
County ; Columbia, Maury Country: 3 miles east of Murfreesboro, Rutherford 
County ; cut on U. S. Highway 41, # mile south of Knox Branch, 9 miles south- 
