PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 565 
Measurements in mm.— 
Brachial 
Length length Width Thickness 
Rinietysetes. santkias. oc) ea... 11.2 10.3 13.7 7.4 
Patsevne (TiF11Gd)). «= ..+ 04 Ti, 11.6 13.9 7.9 
= (Oe) See 10.6 10.2 12.4 6.8 
Types.—Holotype: 117130b; figured paratypes: 111106, I11110a, 117130a; 
unfigured paratypes: I11110b-d. 
Horizon and locality——Lincolnshire formation (Hogskin member) in Tennes- 
see: In the Sowerbyites zone, on road to Thorn Hill, 0.4 mile east of Red Hill, 
SW4NW subquad. of Avondale (T.V.A. 162-SW) Quadrangle; 2.1 miles south- 
west of Mount Eager Church, Hogskin Valley, Powder Springs (T.V.A. 
154-SW) Quadrangle; 1 mile southeast of Washburn, Dutch Valley (T.V.A. 
154-SE) Quadrangle; 3 miles west-southwest of Thorn Hill, Avondale (T.V.A. 
162-SW) Quadrangle; 2 miles southwest of Hall Crossroad, NW4 center sub- 
quad. of Fountain City (T.V.A. 146-SW) Quadrangle. 
Discussion.—This species is characterized by its fairly large size, 2 costae in 
the sulcus, and the lack of ornamentation on the posterior part. It differs from 
the bicostate C. edmundsoni in its larger size, less completely costate valves, and 
wider form. It differs from C. plicata, which it resembles in costation, by its 
different proportions, C. bicostata being wider than long. 
CAMERELLA BREVIPLICATA Billings 
Plate 115, E, figures 32-34 
Camerella breviplicata B1tt1ncs, Geol. Surv. Canada, Paleozoic fossils, vol. 1, p. 304, fig. 295, 
1865. 
Rhynchocamera breviplicata Billings, ULrtcH and Cooper, Geol. Soc. Amer. Special Pap. 13, 
Pp. 251, 1938. 
Type.—Holotype: G.S.C. 759. 
Horizon and locality Boulder in Mystic Conglomerate in Quebec: In Range 
6, Lot 20, Stanbridge Township. 
Discussion.—This is one species of a group common in the upper part of the 
Canadian which has a strongly inflated brachial valve but a smaller pedicle valve 
and is costate only at the anterior. 
CAMERELLA COSTELLATA Cooper, new species 
Plate 112, G, figures 34-41; plate 118, C, figures 20-29 
Shell fairly large for the genus, transversely and broadly elliptical in outline ; 
posterolateral margins straight, forming an angle of about 110°; greatest width 
slightly anterior to the middle; lateral margins narrowly rounded ; anterior mar- 
gin gently rounded. Anterior commissure somewhat narrowly uniplicate. Beaks 
and umbos smooth, anterior two-thirds costellate, with about 20 to 27 costae at 
the anterior margin, 5 to 7 in the sulcus. 
Pedicle valve evenly and strongly convex in lateral profile with the greatest 
convexity at about the middle; anterior profile broadly convex, with moderately 
