304 The American Geologist. November, 1902 
Shell medium sized to large, of three to five volutions. 
The three volutions coil in a very low spire, 170°, but the 
fourth and fifth coil higher 120°. Umbilicus wide. Volutions 
circular at first but with increasing size they are increasingly 
modified becoming indented by contact for one-half the 
hight of the preceding volution; suture scarcely impressed; a 
narrowly rounded elevated keel lies midway between suture 
and peripher}' of the volution, and the periphery and the um- 
bilical margins appear inflated. Shell surface smooth except 
for slight irregular growth varices. These run transverse on 
the inner and under side, arch a little forward across the 
periphery and within the suture, but curve backward to a nor- 
rowly rounded sinus at the keel. 
This and the preceding species are very nearly alike as to 
growth varices, shape of aperture and the mature volutions 
generallv. Both have thick walls the interior rounded and 
gradually filled, or crossed by septal structures in the spire. 
Since both change the relative hight of the spiral during 
growth, tho' in reverse ways, a collection of fragments has the 
appearance of several related species. However these are the 
onlv euomphaloids evidenced in my collections from Hum- 
boldt, Iowa. They are the most abundant specimens. 
Bellerophon sublaevis Hall. 
Bellcrophon sublaevis Hall, 1857, Trans. Albany. Inst., vol. 4, p- 32; 
1856, Geol. Iowa, vol. i. p. 666, pi. 23, figs. 15 a-e. ; Whitfield, 1882, 
Bull. Am. Muse. Nat. Hist-, vol. i, p. 89, pi. 8, f. 6. 7.; White, 1882. 
Geol. Sur. Ind., nth rep. p. 359, pi. 40, f. 5-7.; Hall, 1883, Geol. 
Sur. Ind., I2th re^-, p. 371, pi. 31, f- 6. 7.; Keyes, 1894, Missouri 
Geol. Sur., vol. 5, p. 148. 
Several quite perfect, rather large specimens of a gradu- 
ally expanding, glolx>se, closely involute, thick shelled Bellero- 
phon, one and one-half inches and less in diameter, and an im- 
perfect one two and one-half inches wide but probably the 
same species were collected from the Humboldt oolite. The 
large size is the only observed difference from the Spergen 
Hill, Ind., specimens. 
Loxonema difficile n.sp 
Fig. 3 and 4-. 
The specimens in hand are excellent as compared to others 
of the Kinderhook formation, such as several unidentified 
