PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 923 
Measurements in mm.— 
Brachial Hinge 
Length length Midwidth width Thickness Height 
FEPOUGEG PE ates aloes oh. a siaiw's TS 13.6 GRE: 18.0 4.5 6.9 
Paratype (71350a)...... 15.1 5 17.3 16.6 ? 5.0 
Types.—Holotype: 117848a ; figured paratypes : 71350a,b, 117847a,c, 117848b ; 
unfigured paratypes: 117847b, 117848c-e. 
Horizon and locality—Carters formation in Alabama: In the Ovoplecia beds 
from the quarry 0.3 mile north of Gate City, Leeds (15’) Quadrangle; Cedar 
Mountain, 2 miles southwest of Argo, Birmingham (30’) Quadrangle. 
Dryden formation in Virginia: In the vicinity of Rye Cove, Clinchport 
(T.V.A. 188-NW) Quadrangle. 
Dryden formation in Tennessee: On the Lone Mountain to Tazewell road, 13 
miles northeast of Lone Mountain, Tazewell (T.V.A. 154-NE) Quadrangle; 
on Little Sycamore Creek, $ mile northeast of the west edge of the Howard 
Quarter (T.V.A. 162-NW) Quadrangle. 
Discussion.—This is a species of moderate size which is variable and without 
any one mark of distinction. It is about the size of O. bellula but differs from that 
species in convexity and character of ornamentation. It differs from O. trans- 
versa in being only moderately extended along the hinge and in having its con- 
vexity farther anterior than that of O. transversa which has its convexity near 
the middle. Opikina varia differs from O. minnesotensis in having its maximum 
convexity posterior to that of the Minnesota shell. 
OPIKINA WAGNERI (Okulitch) 
Rafinesquina wagneri OkuLitcH, Canadian Field Nat., vol. 49, No. 6, p. 98, pl. 1, fig. 5, 1935. 
Opikina wagnerit (Okulitch) Satmon, Journ. Paleont., vol. 16, No. 5, p. 506, pl. 87, figs. 19-27, 
1942.—WItson, Geol. Surv. Canada, Bull. 8, p. 94, pl. 8, figs. 14a, b, 1946. 
R. transitionalis (Okulitch) part, idem, p. 97, pl. 1, fig. 4 (not fig. 3), 1935. 
R. williamsi OxutircH, idem, p. 98, pl. 1, fig. 6, 1935. 
Type.—Holotype: Peter Redpath Mus., McGill Univ., Montreal. 
Horizon and locality—Leray = Chaumont formation in Quebec: At St. Vin- 
cent de Paul. 
OPIKINA in Canada 
Dr. Alice Wilson in 1944 described many species of Opikina from the Leray- 
Rockland beds of the Ottawa St. Lawrence Lowland. These species appeared 
first in Transactions of the Royal Society of Canada, ser. 3, vol. 38, sec. 4, 1944, 
and later in Geological Survey of Canada, Bull. 8, 1946. The species are listed 
below in alphabetical order. The first set of figures are the page and plate refer- 
ences to the Royal Society of Canada publication, and the second set of figures 
refer to the Geological Survey of Canada paper. 
Opikina ampla Wilson, p. 190, text fig. 10, No. 12, pl. 2, fig. 26. 
p. 89, text fig. 10, No. 12, pl. 6, fig. 29. 
O. gloucesterensis Wilson, p. 191, text fig. 10, No. 4, pl. 2, fig. 10. 
p. 80, text fig. 10, No. 4, pl. 6, fig. 20. 
