Fauna of the Morrow Group 
239 
1877. Platyceras Nebraseense. White, U. S. Geog. Surv. west of 100th 
Merid., vol. 4, p. 159, pL 12, figs. Sa^d. 
Carboniferous: Near Santa Fe, New Mexico. 
1884. Platyceras Nebrascense. White, 13th Ann. Rep. Geol. Surv. Ind., 
p. 159, pL 32, figs. 15,16. 
Coal Measures: Eugene, Edwardsport, and New Harmony, Indiana. 
1890. Capulus parvus. Keyes, Am. GeoL, vol. 6, p. 9. 
1890. Capulus parvus. Keyes, Proc. Acad. Nat. Sci., PhiL, p. 177, pL 2, 
figs. 14a~c. 
Upper Coal Measures: Indiana; Iowa; Nebraska; Kansas; and 
New Mexico. 
18'94. Capulus parvus, Keyes, Mo. Geol. Surv., vol. 5, p. 180, pi. 54, figs, 
5a"b. 
Upper Coal Measures: Kansas City, Missouri. 
1903. Platyceras parvum. Girty, Prof. Paper, U. S. Geol. Surv., No, 16, 
p. 461, pi. 10, figs. l“la, 2“2a. 
Lower and upper portions of Hermosa formation: San Juan region, 
Colorado. 
This species is the most characteristic one among the gastro- 
pods of the Morrow formations and has been identified from 
ten localities representing each of the fossiliferous horizons of 
the group. Considerable variation is displayed in the size and 
degree of curvature of the different individuals but all are refer- 
able to this common Pennsylvanian species. One specimen, in 
which the shell surface has been well preserved, is marked by 
numerous crowded and strongly sinuous lines of growth but 
in m.O'St cases the preservation is that of an internal cast. 
The half dozen specimens from station 210 are all dwarfed, 
the largest having a diameter of less than 10 mm. Some of 
them are evidently mature despite their small size. 
Horizon and locality. Hale formation: East Mountain, Fay- 
etteville, Arkansas (Stations 137 and 149). Brentwood lime- 
stone: near Fayetteville, Arkansas (Station 135) ; Sawney Hol- 
low, Oklahoma (Station 210), Kessler limestone: East Moun- 
tain, Fayetteville, Arkansas (Station 209). Morrow formation: 
near Tahlequah (Station 293), Choteau (Stations 295, 302, and 
306), and Ft. Gibson (Station 303), Oklahoma. 
