PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 201 
Oklahoma: At Rock Crossing of Hickory Creek, about center sec. 35, T. 5 S., 
R.1 E., Criner Hills, Carter County. 
Discussion.—This species is characterized by the crowding of striae along the 
sides and its long slender form. It differs from L. lirata Cooper, new species, 
in its laterally confined striate ornamentation. 
LINGULELLA HURONENSIS (Billings) 
Lingula huronensis Bittincs, Canadian Nat. Geol., vol. 4, p. 433, fig. 9, 1859; Geol. Canada, 
p. 124, fig. 48, 1863—RayMonp, Ann. Carnegie Mus., vol. 7, p. 219, 1911.—SINCLAIR, 
Trans. Roy. Soc. Canada, ser. 3, vol. 30, sec. 4, p. 60, pl. 4, figs. 1-3, 1945.—WILSoN, 
Geol. Surv. Canada, Bull. 8, p. 19, pl. 1, figs. 14, 15, 1946. 
Types.—Lectotype: G.S.C. 1159; paratype: G.S.C. 11592. 
Horizon and locahity.—Black River, St. Joseph Island, Lake Huron. 
LINGULELLA ? HURONENSIS MINGANENSIS (Twenhofel and Whiting) 
Lingula huronensis Bituncs, Canadian Nat. Geol., vol. 4, p. 433, fig. 9, 1859. 
L. huronensis minganensis TWENHOFEL and WHITING, Geol. Soc. Amer. Special Pap. 11, 
Pp. 44, pl. 7, fig. 15, 1938. 
Type.—Holotype in Twenhofel Collection. 
Horizon and locality.—Basal Mingan formation, Mingan Islands, St. Law- 
rence River. 
LINGULELLA KINGSTONENSIS (Billings) 
Lingula kingstonensis Brttincs, Geol. Surv. Canada, Paleozoic fossils, vol. 1, p. 48, fig. 51 
(adv. sheets, 1862), 1865; Geol. Canada, p. 141, fig. 74, 1863. 
Types.—Lectotype (G. W. Sinclair, 1945): G.S.C. 1158; paratypes: G.S.C. 
1158a-c,e,f. 
Horizon and locality—Black River formation, near Long Island, near Kings- 
ton, Ontario, Canada. 
LINGULELLA LIRATA Cooper, new species 
Plate 2, C, figures 8, 9; plate 5, H, figures 20-25; plate 6, D, figures 16, 17; plate 11, B, 
figures 2-4; plate 28, F, figures 17-23 
Lingula lyelli WiLLaRp (not Billings), Bull. Mus. Comp. Zool., Harvard Coll., vol. 68, No. 6, 
p. 256, pl. 1, fig. 2, 1928. 
Elongate oval in outline, length slightly less than twice the width; lateral mar- 
gins very slightly convex and forming small shoulders where they join the pos- 
terolateral margins. Beak forming an angle of about 80°. Surface marked by fine 
elevated concentric lines which are crowded and prominent in the lateral and 
posterolateral regions on the lateral slopes but indistinct on the median part of 
the shell. Median region appearing smooth. 
Pedicle valve deepest at a point about one-third the length from the beak; 
anterior slope long and gentle; umbonal region narrowly swollen, the swelling 
extending for the whole length but becoming gentler anteriorly ; anterior profile 
moderately strongly convex. Posterolateral slopes short and steep. 
