PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 427 
M. semtsulcata but differs in details of the costellae, more robust cross section, 
and more quadrate form. 
MULTICOSTELLA SAFFORDI (Hall and Clarke) 
Orthis ? saffordi Hatt and CLarKE, Pal. New York, vol. 8, pt. 1, pp. 218, 340, pl. 5A, 
figs. 38-40, 1892. 
Multicostella saffordi (Hall and Clarke) ScHucHERT and Cooper, Mem. Peabody Mus. Nat. 
Hist., vol. 4, pt. 1, p. 98, 1932. 
Although many specimens of Multicostella from eastern Tennessee appear in 
the National Collection and that of the Geological Survey, it has proved impos- 
sible to identify any of them with Hall and Clarke’s description of O. ? saffordi. 
Inasmuch as their specimen could have come from any one of numerous horizons 
and their description is so brief and noninformative, it is at present impossible 
to identify the specimen except to be sure that it is a Multicostella. The speci- 
men is said to have come from Knoxville, Tenn. This probably means that it 
could have been derived from an area of several miles radius from Knoxville, an 
area that includes beds from the Lenoir to the Sevier, but derivation from the 
Arline formation seems probable. 
Type.—Holotype: N. Y. State Mus. 7932/1. 
MULTICOSTELLA SEMISULCATA Cooper, new species 
Plate 64, D, figures 17-26; plate 71, G, figures 36-40 
Multicostella saffordi SCcHUCHERT and Cooper, (not Hall and Clarke), Mem. Peabody Mus. 
Nat. Hist., vol. 4, pt. 1, p. 98, pl. 8, figs. 23, 27, 1932. 
Shell large for the genus, wider than long; hinge as wide or wider than the 
width at the middle; valves subequally convex with the brachial valve slightly 
the deeper; sides rounded; anterior margin broadly rounded; anterior margin 
rectimarginate to broadly uniplicate; lateral commissure deflected toward the 
brachial valve in the posterior part; surface multicostellate ; costellae and striae 
about equal in width, costellae numbering about 8 in 5 mm. at the front of a 
large adult. 
Pedicle valve with unevenly convex lateral profile, the posterior half having 
a greater convexity than the anterior half which is flattened; anterior profile 
broadly triangular with the median area narrowly humped-up and with flat but 
moderately steep slopes to the margins. Umbonal and posteromedian region swol- 
len and forming a broad fold; anterior half somewhat flattened ; posterolateral 
slopes long and gentle ; interarea moderately long, apsacline ; interior with muscle 
field occupying posterior third. 
Brachial valve moderately convex in lateral profile, broadly convex in anterior 
profile; umbo gently swollen, sulcate; sulcus prominent but shallow in the pos- 
terior half, not defined on the anterior half; median and anteromedian areas 
somewhat swollen; slopes to margins gentle; interior with strongly thickened 
notothyrial platform, stout cardinal process. 
