loiva Carboniferous Formations — Sardeson. 305 
specimens figured by Weller* tho' not better than the L. yandel- 
lanum Hall from Spergen Hill, Ind., a species which is con- 
spicuous perhaps because of it's good perservation. Compar- 
ed to this one, the specimenjs from Humboldt are ten diameters 
larger tho' of so nearly the same taper that inferior specimens 
might be taken for the same species in spite of size in view of 
the fact that some others which were firjst described from 
Spergen Hill fossils were based on minute or immature shells. 
Girtyt and Keyes % also have figured specimens of Loxonema 
without names, but near enough geologically to deserve men- 
tion here. 
The shell of L. difficile //. sp. is large, of 15 or less volu- 
tions, gradually expanding to a length of 12 cm. with apical 
angle of near 25". Each volution is impressed by one half the 
preceding- one measuring from the superior suture to the lower 
inner angle. Counting ten units in that distance, the surface 
is distinctly concave for two units, equally convex for the next 
two, strongly convex crossing the periphery for the fifth unit 
to the line of the inferior suture, thence gently convex below 
but rounding narrowly to the imperforate columella. The di- 
ameters measured vertically and transversely are nearly equal 
but obliquely the bight and width are as 8 to 5. The suture is 
distinct. Surface smooth except for fine growth varices which 
run sigmoidally, the backward curve above the periphery be- 
ing about half as deep as wide, the forward curve below it be- 
ing equally deep tho' with longer radius. The shell thickness 
is rather uniform in the spire and the internal cavity changes, 
gradually from subangular to oval. 
Seven specimens w^ere found at Humboldt and at Rut- 
land, in the Kinderhook strata. 
Murchisonia sp. indet. 
One specinuen was found at Rutland, la. It is an entire 
shell rolled in a pisolith, and discovered in section by grinding. 
It is 18 mm. long with acute apex, and 12 volutions of which 
the last is six mm. across, measuring obliquely. A marked 
angulation lies below the middle and the suture is distinct. The 
columella is minutely perforate. The surface is not shown. 
* Kinderhook Faunal Studie.«; Trans. Acad., St. Louif, vol. ix, x, xi. 
t Monogr. 32, U. S. G. S., pi. 66, f. 9. 
t Missouri Geol. Sur., vol. v, pi. 55, f. 2. 
