PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 591 
ing sulcus prominent and subangular. Flanks concave to slightly convex and 
with steep slopes to the margins. 
Brachial valve equal in depth to or slightly deeper than the pedicle valve, gently 
convex in lateral profile and with the greatest curvature at the umbo; moderately 
convex in anterior profile. Fold originating at the middle, somewhat narrowly 
rounded, moderately elevated. Flanks strongly rounded and with steep slopes to 
the margins. 
Interior: Pedicle valve provided with an elongate spondylium supported by a 
septum that extends from the beak for fully a third the length. Cruralium of 
brachial valve short, supported by a septum extending from the beak nearly to 
the middle of the valve. 
Measurements in mm.— 
Brachial 
Length length Width Thickness 
PAI OYE ao, «hielo eile nus me 2 28 6.2 5.9 6.5 4.3 
Earapgne, CUUEZIOA) 6 oss aie ees ding we 6.5 6.4 7.4 3.3 
“ Crr1greeyes Tae 5.6 5.4 6.0 3.1 
Types.—Holotype: 111310b; figured paratype: 111310a; unfigured paratypes: 
1113 0c-f. 
Horizon and locality—Bromide formation (Pooleville member-O-roplecia 
gouldi zone) in Oklahoma: At Rock Crossing of Hickory Creek, about center 
sec, 35, (.5 5., R. tE., Criner Hills, Carter County, 
Discussion—These interesting little shells have been tentatively placed in the 
genus Neostrophia because of their camarelloid interiors and the strong rounded 
fold of the brachial valve. They differ from known Neostrophia in their small 
size and lack of anterior plication other than the median fold. 
NEOSTROPHIA SUBCOSTATA Ulrich and Cooper 
Plate 120, B, figures 7-16 
Neostrophia costata UtricH and Cooper, Journ. Paleont., vol. 10, No. 7, p. 631, 1936; Geol. 
Soc. Amer. Special Pap. 13, p. 252, pl. 56G, figs. 18, 22-31, 35, text fig. 14, 1938. 
Types.—Holotype: 66309a ; paratypes: 66309b-f. 
Horizon and locality.— Boulder in the Mystic conglomerate in Quebec, Canada: 
Range 6, Lot 20, Stanbridge Township, near Mystic. 
NEOSTROPHIA ? sp. 1 
Plate 120, C, figs. 17, 18 
Shell small, pentagonal in outline ; greatest width anterior to the middle; valves 
subequally convex ; surface smooth. Pedical valve with a shallow sulcus originat- 
ing just posterior to the middle. Brachial valve with a rounded, low fold set off 
from the flanks by shallow, narrow grooves. Fold often with small median groove 
and sulcus with faint median costa. Both valves with a long median septum. 
Measurements in mm.—Brachial valve, length 4.3, width 3.8. 
Figured specimens.—117176a,b. 
