PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 723 
terior profile; umbo moderately swollen and somewhat narrowed at the beak; 
median region moderately swollen and with steep anterior and posterior slopes 
of about equal proportions ; lateral slopes moderately long and moderately steep ; 
interarea long and orthocline. Interior with narrow diductor scars and moder- 
ately large callosities at, or slightly anterior to, the middle. 
Brachial valve moderately concave, maximum concavity anterior to the middle ; 
mumbo concave, the concavity produced anteriorly nearly to front margin as a 
shallow, poorly defined sulcus. Flanks bounding sulcus in posterior somewhat 
flattened. Anterior third fairly strongly geniculated. Interior with short blade- 
like brachiophores and thick cardinal process; median ridge low, elevated an- 
teriorly ; adductor field small. Pallial trunks moderately impressed. 
Measurements in mm.— 
Brachial Mid- Hinge Surface  Thick- 
Length length width width length ness Height 
FIGIGHY PE” 62. Peladis wos 20.9 17.3 27.0 28.4 25.5 5.0 6.9 
Paratype (117430)... 21.5 18.6 27.4 29.2 25.6 4.4 6.4 
Types.—Holotype: 117431a; figured paratypes: 117431b,c; measured para- 
type: 117430. 
Horizon and locality—Lenoir formation (base of Billingsaria zone) in Ten- 
nessee: On both sides of east-west road leading into marble quarry, 1 mile north- 
east of Friendsville, Concord (T.V.A. 138-SE) and Louisville (T.V.A. 138-SE) 
Quadrangles. 
Discussion—For differences between this species and T. medius see discussion 
under that species. 
TITANAMBONITES sp. 1 
Plate 177, B, figure 11 
This is a large specimen coming from the massive limestone above the Mac- 
lurites beds and below the Pratt Ferry formation, which approaches T. amplus 
(Raymond) in size but is shorter, more rounded in lateral profile, and seems to 
have a greater height than specimens from McMullens, Tenn. 
Figured specimen.—117432. 
Horizon and locality—“‘Lenoir” (part with Christiania= Little Oak) in Ala- 
bama: 0.2 mile southeast of Pratt Ferry, Blocton (15’) Quadrangle. 
Genus SOWERBYITES Teichert, 1937 
Sowerbyites TEICHERT, Rep. 5th Thule Exped., 1921-24, vol. 1, No. 5, p. 66, 1937. 
Externally like Sowerbyella forming a semicircle in outline, interareas well 
developed on both valves; hinge wide; surface marked by costellae of two sizes. 
Delthyrium partially closed by a rudimentary pseudodeltidium. 
Pedicle interior with muscle field occupying most of the median portion of the 
valve. Diductor impressions divergent, exceptionally long, extending anterior 
to the middle. Adductor impressions small, located within the delthyrial cavity. 
Adjustor impressions located outside the diductors, elongate, separated from 
them by a more or less well developed ridge. Teeth moderately large, composed 
