Fauna of the Morrow Group 
209 
toward the cardinal portions and more gently toward the an- 
terior and posterior margins, the middle portion of the valve 
slightly flattened dorsally; beaks rather depressed, convex, and 
placed nearer the anterior end than the middle. 
Surface of internal cast marked with distinct, concentric, 
irregular undulations which are less distinctly shown on the 
exfoliated surface of the valve. The distance from crest to 
crest of the undulations, throughout the middle of the valve, 
averages about 1.5 mm. 
Dimensions of the two imperfect specimens are approximately : 
length, 34.5 mm., 31.5 mm. ; height, 29.0 mm., 21.5 mm. ; con- 
vexity, 11.5 mm., 9.0 mm. 
Remarks. The material referred to this species consists of 
a somewhat incomplete cast of the interior of a left valve and 
an imperfect left valve of another individual which is strongly 
exfoliated, both from a single locality in the Kessler limestone. 
E. suhtruncata resembles E. aspinw alien sis but may be differen- 
tiated from it by the proportionately greater length, less elevated 
beaks, the dorsal flattening of the middle portion of the valve, 
and the nearly straight dorsal outline. 
Horizon and locality. Kessler limestone : East Mountain, Fay- 
etteville, Arkansas (Station 209). 
Edmondia maccoyii Hind? 
Plate XV, figure 10. 
1855. Edmondia scalaris. M’Coy, Brit. Pal. Foss, p. 502, pi. 3H, fig. 6. 
(non Venerupis scalaris M’Coy, 1844). 
Carboniferous limestone: Lowick, Northumberland, England. 
1888, Edmondia scalaris (pars). Etheridge, Brit. Foss., pt. i., Paleozoic, 
p. 284. 
1899. Edmondia MacCoyii. Hind, Brit. Carb. Lamell., vol. i., pt. iv., 
p. 329, pi. XXXVI., figs. 8, 23-30. 
Carboniferous limestone: Settle, Yorkshire; Thorpe Cloud, Castle- 
ton and Park Hill, Darbyshire; Narrowdale, Staffordshire; The 
Coomb and Lowick, Northumberland, England. 
Lower Limestone of Auchenskeith and Dockra, Scotland. 
Carnteel, Tyrone, Ireland. 
Millstone Grit series: Cayton Gill beds, near Harrogate, England. 
A left valve of an Edmondia from the Kessler limestone, pre- 
served as both an internal cast and external mold, neither of 
which is quite complete, is referred with a fair degree of con- 
