69 
Remarks. The short hinge-line and spinose surface place this form in 
Hall and Clarke’s Fimbriate and Waagen’s Reticulariinae. It completely 
lacks the dental plates of pedicle valve and the median septum of each 
valve characteristic of Retieularia and thus falls within Gemmellaro’s 
genus Squamularia. 1 The muscle markings in the pedicle valve of our form 
are very faintly impressed, hardly noticeable except for the radiating lines. 
We have here apparently a transitional form connecting a plicate non- 
varicate shell with a non-plicate varicate one; a development from a plicate 
Mississippian spiriferoid shell to the typical Squamularia of the Pennsyl- 
vanian with its characteristic low, irregular varices and no plications. 
In form this species closely resembles Brachythyris chouteauensis 
Weller from the Kinderhook of Mississippi valley 2 and was first so identi- 
fied, for most of the specimens are exfoliated. In the following comparison 
with B. chouteauensis the Minnewanka species is placed in parenthesis. 
Length of pedicle valve 22 mm. (30 mm.), of brachial valve 20 mm. (26 
mm.); greatest width 24*5 mm. (32 mm.); length of hinge-line 13*5 mm. 
(19 mm.); thickness of shell 17 mm. (19 mm.), of pedicle valve 10 mm. 
(12 mm.), of brachial valve 7 mm. (7 mm.); plications upon fold and in 
sinus 2-4 (0-2), upon each lateral slope 8-11 (8-14). The Minnewanka 
form is slightly larger, with a greater convexity of the pedicle valve, and 
a stronger incurvature to the beak; plications are less prominent and less 
elevated; those of the lateral slopes are usually flat topped, with very 
narrow, abruptly depressed interspaces. An especially noticeable differ- 
ence is that the entire surface is spinose-striate (in B. chouteauensis the 
plications are broadly rounded and the surface lacks longitudinal strife) . 
Spirifer ? peculiaris Shumard has a much higher cardinal area of the 
pedicle valve, fewer plications (5-8) upon each lateral slope, and the sinus 
and fold smooth or with a single median plication in the sinus and a corres- 
ponding furrow in the top of the fold. (There appears to be some doubt 
as to the presence or absence of spines in this species.) Girty 3 places it 
under Retieularia with a question mark, because some exfoliated specimens 
from the Chouteau limestone of Missouri (the home of Shumard’s type) 
“appear to have possessed a finely lamellose-spinose surface.” Weller 4 
places the Missouri Chouteau limestone form of this species under Brachy- 
thyris, which genus lacks radiating strise. 
Specific name given because of the depressed plications; these are low, 
frequently flat topped, at times very obscure. 
Locality and Horizon. In the Minnewanka region in the Lower Mis- 
sissippian of section 2-24 (C), 29 (r). 
Genus, Eumetria Hall 
Eumetria marcyi (Shumard) 
1854. Terebratula marcyi Shumaid, Marcy’s Rep. U.S. Expl. Red River of 
Louisiana, p. 177, PI. 1, fig. 4; Retzia verneuiliana Hall, 1858, Trans. 
Albany Inst., vol. 4, p. 9; Hall, 1858, Geol. Iowa, vol. 1, pt. 2, 
p. 657, PI. 23, figs. 1 a-d; Eumetria verneuiliana Hall, 1883, 12th 
i Girty, U. S. Geol. Surv., Prof. Paper 16,p. 387, 1903. 
a State Geol. Surv. , 111. , Mon. 1, 1914, p. 373. PI. 57, figs. 4-11. 
* U.S. Geol. Surv., Mon. 32, pt. 2, 1899, p. 557. 
4 Geol. Surv., 111., Mon. 1, 1914, p. 381. 
