48- 
Dielasma arkansanum Weller 
1914. Dielasma arkansanum Weller, 111. Geol. Surv., Mon. 1, p. 269, 
PI. 31, figs. 35-44; Mather, 1915, Bull. Sci. Lab., Denison Univ., 
18, p. 180, PI. 11, figs. 12-1 2b. 
Remarks. The somewhat crushed state of our single specimen makes 
the determination of place of greatest width difficult; it is surely not 
posterior to mid-length of shell and most probably some distance anterior 
to it. In length, breadth, and thickness, and in other proportions it is 
similar to D . arkansanum. It lacks the spatulate outline of D. subspatu- 
latum Weller. The absence of a distinct median sinus removes it from D. 
bovidens of the Pennsylvanian. 
Locality and Horizon. Lower Pennsylvanian of Arkansas. In the 
Minnewanka region in the Permian of section 1-14 (R). 
Genus, Spirifer Sowerby 
Spirifer whiineyi Hall 
1858. Spirifer whitneyi Hall, Geol. Surv., Iowa, 1, pt. 2, p. 502, PI. 4, fig. 2; 
Hall, 1867, Pal. New York, 4, pp. 243, 417; Spirifera whitneyi Hall, 
1883, Second Ann. Rept. N.Y. State Geologist, PI. 55, figs. 18, 19; 
Whiteaves, 1891, Contrib. to Can. Pal. 1, p. 222; Spirifer whitneyi 
Hall and Clarke, 1893, Pal. N.Y. 8, pt. 2, pp. 24, 57, PI. 30, figs. 
18, 19; Kindle, 1909 ?, U.S. Geol. Surv., Bull. 391, p. 24, PI. 8, 
figs. 2-5a; Haynes, 1916, Annals Carnegie Mus., vol. 10, p. 33, 
PI. 5, fig. 5, PI. 6, figs. 8-11. 
Remarks. The Minnewanka form agrees very closely with those from 
Iowa; it differs principally in its more alate outline and its fewer plications. 
This difference is, however, very slight. The majority at least of the 
specimens from Colorado and New Mexico, as described and figured by 
Kindle, under this name, are larger, more gibbous, subquadrate, the sides 
being almost vertical or with rounded cardinal extremities; these very 
probably belong to the variety monticola. S. whitneyi animosensis Girty 
is very similar in size and plications, but has a very high, flat, cardinal area, 
at times the beak incurved very slightly. Upon comparison with Haynes’ 
material from the Three Forks formation of Montana our specimens were 
noticeably in perfect agreement. 
Locality and Horizon. Upper Devonian of Iowa, and the Rockies. 
In the Minnewanka region in the Upper Devonian of sections 2-38 (r), 
45 (?); 4-5 (R). 
Spirifer whitneyi monticola Haynes 
1916. Spirifer whitneyi monticola Haynes, Annals Carnegie Mus., vol. 10, 
p. 36, PI. 6, figs. 1-7; cf. Spirifer whitneyi Kindle, 1909, U.S. Geol. 
Surv., Bull. 391, p. 24, PL 8, figs. 2-5a. 
