PARTI CHAZYAN AND RELATED BRACHIOPODS—COOPER 875 
TRIGRAMMARIA WILSONAE Cooper, new species 
Plate 263, B, figures 10-16 
Shell of about medium size for the genus, subrectangular in outline; wider 
than long and with the hinge narrower than the width at the middle; sides gently 
rounded ; anterior margin subnasute; anterior commissure narrowly uniplicate ; 
surface finely costellate, strong costellae alternating with up to 4 fine costellae. 
Pedicle valve uneven in lateral contour, the umbonal region gently convex but 
the anterior three-fourths gently concave; anterior profile broadly and gently 
concave; umbonal region gently convex; median region marked by a shallow 
and narrow sulcus that deepens toward the anterior margin; flanks bounding 
sulcus gently concave; sides slightly bent in the direction of the pedicle valve. 
Brachial valve gently convex in lateral profile and with the maximum con- 
vexity at about the middle; anterior profile broadly and moderately convex; 
beak marked by a smooth swollen spot; umbo marked by a shallow, narrow sul- 
cus that disappears at about the valve middle; median region swollen, the swell- 
ing extending to the lateral slopes which are short and steep; median fold origi- 
nating just anterior to the middle, narrowly rounded. 
Measurements in mm.—Holotype, length, 14.3, brachial length 13.9, midwidth 
16.9, hinge width 14.9, thickness 4.5, height 4.7. 
Type.—Holotype: 117753. 
Horizon and locality —Rockland formation (Napanee member) in New York: 
From a road cut on the east side of New York Highway 12 on the south side of 
Sugar River, 44 miles south-southeast of Port Leyden, Port Leyden (15’) 
Quadrangle. 
TRIGRAMMARIA WINCHELLI (Hall and Clarke) 
Plate 263, A, figures 1-9 
Strophomena winchelli HAtt and CLarKkE, Pal. New York, vol. 8, pt. 1, p. 344, pl. 9, figs. 10, 
12-14, 1892—-WINCHELL and SCHUCHERT, Geol. Minnesota, vol. 3, pt. 1, p. 394, pl. 31, 
fig. 11, 1895. Hatt and CrarkE, 48th Rep. New York State Mus., vol. 2, 1895, p. 344, 
pl. 4, figs. 31-33, 1805; 14th Rep. State Geol. New York for 1804, p. 344, pl. 4, figs. 31-33, 
1897.—RaascH in SHROCK and Raascu, Amer. Midland Nat., vol. 18, No. 4, p. 492, 
pl. 4, fig. 10, 1937. 
Types —Figured hypotypes: 117752a,b, 123280. 
Horizon and locality.—Platteville formation (McGregor member) in Minne- 
sota, Wisconsin, and Illinois. 
FURCITELLA Cooper, new genus 
(Latin furca, fork) 
Shells small, attaining a width of about 0.8 inch; generally wider than long; 
subrectangular in outline, with the hinge generally equal to or slightly less than 
the midwidth. Biconvex, but the valves unequal in convexity, the brachial valve 
having the greater convexity and the pedicle valve usually flattened to somewhat 
concave in the anterior half. Surface costellate, costellae subequal. Foramen 
large; pseudodeltidium strongly convex. Pseudopunctate. 
